Search

Weaning is one of the most stressful events in the pig's life, which disrupts physiological balance and leads to oxidative stress. It is reported that glucose oxidase supplementation could alleviate oxidative stress in animals by increasing the concentration of antioxidant enzymes in vivo. The purpose of this study was to evaluate the effects of dietary supplementation of Aspergillus niger-expressed glucose oxidase (AN-GOX) on growth performance, nutrient digestibility, faecal microbiota, faecal gas emission and serum antioxidant enzyme parameters in weaning pigs. A total of 120 21-day-old weaning pigs [(Yorkshire ×Landrace) × Duroc] with an initial body weight of 6.54 ± 0.55 kg were used in a 21-day experiment (phase 1, days 1-7; phase 2, days 8-21) with a completely randomized block design. Pigs were randomly divided into 4 treatment groups with 6 replicate pens per treatment and 5 pigs per pen (2 barrows and 3 gilts). Dietary treatments were corn-soybean meal-based basal diet supplemented with 0, 0.01, 0.03 or 0.05% AN-GOX (1000 unit/g). The results of this study showed that average daily gain during days 1-7 and 1-21 and the concentrations of serum glutathione peroxidase and glutathione increased linearly at graduated doses of AN-GOX increased in the diet. However, dietary supplementation of AN-GOX had no effects on the apparent nutrient digestibility, faecal microbiota and faecal gas emission. In conclusion, supplementing AN-GOX to the diet of weaning pigs ameliorated weaning stress, which manifested as the increase in serum antioxidant enzyme levels, thus improving growth performance. The suitable dosage of AN-GOX used in the diet of weaning pigs was 0.05%.

Subsequent to escape from intense herbivory in the native range, invasive plants are expected to reduce allocation to costly anti‐herbivory defences and have greater competitive ability than co‐occurring native species. Given that invasive alien plants often occur in open habitats where light is less limited, it is reasonable to hypothesize that invasive plants should express high concentrations of gibberellins that enable them to allocate more biomass to roots, and thus have higher competitive ability than native plants. To test this prediction, we grew five congeneric pairs of invasive alien plants and native plants under two levels of nutrient availability (low versus high) and treated a half of the plants with a gibberellin biosynthesis inhibitor, paclobutrazol. Paclobutrazol significantly decreased aboveground, belowground and total biomass of the test plants. Interestingly, the effects on belowground biomass were significantly stronger for invasive plants than for native plants. A similar pattern was found for total biomass (marginally significant effect p = 0.0592). Additionally, paclobutrazol decreased root mass fraction for invasive plants, but tended to increase it for native plants. Our findings suggest that plant hormones can differently regulate biomass allocation of invasive and native plants, and thus contribute to greater growth of invasive plants compared to native plants.

This study was conducted to investigate the effects of supplementing glucose oxidase (GOX; 1000 unit/g) to the diet of growing pigs on growth performance, apparent nutrient digestibility, faecal bacteria counts, and serum antioxidant enzyme parameters. A total of 200 growing pigs [(Yorkshire × Landrace) × Duroc] with an initial body weight of 23.3 ± 0.33 kg were used in a 42-day trial. Pigs were randomly allotted to four dietary treatments with 10 replicate pens per treatment and five pigs (mixed sex) per pen based on the initial body weight. The dietary treatments consisted of the basal diet (control), control + 0.01% GOX, control + 0.02% GOX, or control + 0.03% GOX. One unit of GOX concentration is defined as the amount of enzyme which oxidises 1 μmol β-D-glucose per minute to D-gluconic acid and hydrogen peroxide at 37 °C and pH5.5. Body weight on day 42 (p = .035), average daily gain during days 22–42 (p = .001) and 1-42 (p = .001), average daily feed intake during days 22–42 (p = .008) and 1–42 (p = .020), apparent nitrogen digestibility on day 42 (p = .029), apparent energy retention on day 42 (p = .032), and the concentrations of serum glutathione peroxidase (p = .044) and glutathione (p = .032) on day 42 increased linearly at graduated doses of GOX increased in the diet. Therefore, supplementing GOX to the diet of growing pigs could improve the apparent nutrient digestibility and serum antioxidant enzyme parameters in a dose-dependent manner, thus improving growth performance. In this study, the suitable dosage of GOX used in the diet of growing pigs was 0.03%.Highlights Feeding growing pigs with GOX containing diet has beneficial effects on the growth performance Dietary supplementation of GOX could improve the apparent nutrient digestibility in growing pigs The antioxidant status of growing pigs has improved by GOX supplementation.

In Saccharomyces cerevisiae under conditions of nutrient stress, meiosis precedes the formation of spores. Although the molecular mechanisms that regulate meiosis, such as meiotic recombination and nuclear divisions, have been extensively studied, the metabolic factors that determine the efficiency of sporulation are less understood. Here, we have directly assessed the relationship between metabolic stores and sporulation in S. cerevisiae by genetically disrupting the synthetic pathways for the carbohydrate stores, glycogen (gsy1/2Δ cells), trehalose (tps1Δ cells), or both (gsy1/2Δ and tps1Δ cells). We show that storage carbohydrate-deficient strains are highly inefficient in sporulation. Although glycogen and trehalose stores can partially compensate for each other, they have differential effects on sporulation rate and spore number. Interestingly, deletion of the G1 cyclin, CLN3, which resulted in an increase in cell size, mitochondria and lipid stores, partially rescued meiosis progression and spore ascus formation but not spore number in storage carbohydrate-deficient strains. Sporulation efficiency in the carbohydrate-deficient strain exhibited a greater dependency on mitochondrial activity and lipid stores than wild-type yeast. Taken together, our results provide new insights into the complex crosstalk between metabolic factors that support gametogenesis.

The effect of cropping regime on nitrogen (N) uptake in two coexisting plant grass species (Avena sativa and Agropyron cristatum) was investigated. The two grass species were cultivated by monocropping or intercropping. 15N-labeling was used to examine N uptake of NH4+ versus NO3− at 0–5 cm and 5–15 cm soil depths. The aboveground and total biomass of intercropped A. sativa was 1.3 times greater than monocropped A. sativa. The biomass of A. cristatum did not change between cropping systems. In the 0–5 cm soil layer, uptake of NO3− by A. sativa was 0.5 times less in the intercropped system than in the monocropped system, whereas uptake of NO3− by A. cristatum was 2.0 times more in the intercropped system. In the 5–15 cm depth, intercropping did not change N uptake by A. sativa but decreased NO3− uptake to 0.6 times by A. cristatum. Complementarity in N uptake between A. sativa and A. cristatum in the upper 0–5 cm soil layer is conducive to biomass accumulation. Intercropped A. sativa and A. cristatum does not compete strongly for soil resources and can alter their N uptake patterns to optimize biomass production.

The Novel Defense Hypothesis predicts that introduced plants may possess novel allelochemicals which act as a defense against native generalist enemies. Here, we aim to test if the chemicals involved in allelopathy in the invasive plant Wedelia trilobata can contribute to higher resistance against generalist herbivore and pathogen enemies by comparing with its native congener W. chinensis in controlled laboratory conditions. The allelopathic effects of the leaf extract from W. trilobata on the generalist enemies were also assessed. We showed that the larvae of two moth species preferred W. chinensis over W. trilobata. The growth rate of larvae feeding on W. trilobata leaves was significantly lower than those feeding on W. chinensis leaves. When detached leaves were inoculated with phytopathogens, the infected leaf area of W. trilobata was significantly smaller than that of W. chinensis. In addition, the leaf extract of W. trilobata also effectively inhibited the growth of the larvae and the mycelial growth of the phytopathogens. Our results indicate that the defenses of invasive W. trilobata against generalist herbivore and pathogen enemies are stronger than that of its native congener, which may be attributed to the allelopathic effects. This study provides novel insights that can comprehensively link the Novel Defense, Behavioral Constraint and Enemy Release hypotheses. These combined hypotheses would explain how invasive plants escape from their natural specialist enemies, where their allelopathic chemicals may deter herbivorous insects and inhibit pathogen infection.

Simple Summary In bumblebee colonies, the authority of male reproduction is not entirely controlled by the queen. Workers who lose mating ability could also produce haploidy males. The conflict over the reproduction of males in bumblebee colonies becomes more evident compared to the higher eusocial honeybees. However, the reproductive characteristics of worker-born males in bumblebees remain unclear. Here, we evaluated the body size and reproductive ability of males produced by worker and queen in Bombus terrestris. Smaller size and slighter individuals’ weight but equally high sperm viability was found in worker-born males compared to that of queen-born males. Moreover, worker-born males performed as excellently as queen-born males in copulation and colony development of the mated queens, such as queen egg laying, colony foundation, and colony size. This study contributes the new knowledge of the reproductive biology of eusocial bees. Abstract Queen-worker conflict over the reproduction of males exists in the majority of haplodiplioidy hymenpteran species such as bees, wasps, and ants, whose workers lose mating ability but can produce haploid males in colony. Bumblebee is one of the representatives of primitively eusocial insects with plastic division labor and belongs to monandrous and facultative low polyandry species that have reproductive totipotent workers, which are capable of competing with mother queen to produce haploid males in the queenright colony compared to higher eusocial species, e.g., honeybees. So, bumblebees should be a better material to study worker reproduction, but the reproductive characteristics of worker-born males (WMs) remain unclear. Here, we choose the best-studied bumblebee Bombus terrestris to evaluate the morphological characteristics and reproductive ability of WMs from the queenless micro-colonies. The sexually matured WMs showed smaller in forewing length and weight, relatively less sperm counts but equally high sperm viability in comparison with the queen-born males (QMs) of the queenright colony. Despite with smaller size, the WMs are able to successfully mate with the virgin queens in competition with the QMs under laboratory conditions, which is quite different from the honeybees reported. In addition, there was no difference in the colony development, including the traits such as egg-laying rate, colony establishment rate, and populations of offspring, between the WM- and the QM-mated queens. Our study highlights the equivalent reproductive ability of worker-born males compared to that of queens, which might exhibit a positive application or special use of bumblebee rearing, especially for species whose males are not enough for copulation. Further, our finding contributes new evidence to the kin selection theory and suggests worker reproduction might relate to the evolution of sociality in bees.

SummaryInvasive plant species often exhibit greater growth and lower anti-herbivory defense than native plant species. However, it remains unclear how nutrient enrichment of invaded habitats may interact with competition from resident native plants to affect growth and defense of invasive plants.In a greenhouse experiment, we grew five congeneric pairs of invasive and native plant species under two levels of nutrient availability (low vs. high) that were fully crossed with simulated herbivory (clipping vs. no-clipping) and competition (alone vs. competition).Invasive plants produced more gibberellic acid, and grew larger than native species. Nutrient enrichment caused a greater increase in total biomass of invasive plants than of native plants, especially in the absence of competition or without simulated herbivory treatment. Nutrient enrichment decreased leaf flavonoid contents of invasive plants under both simulated herbivory conditions, but increased flavonoid of native plants under simulated herbivory condition. Nutrient enrichment only decreased tannins production of invasive species under competition. For native species, it enhanced their tannins production under competition, but decreased the chemicals when growing alone.The results indicate that the higher biomass production and lower flavonoids production in response to nutrient addition may lead to competitive advantage of invasive species than native species.

SummaryUnion of two gametes to form a zygote is a defining event in the life of sexual eukaryotes, yet the mechanisms that underlie cell-cell fusion during fertilization remain poorly characterized. Here, in studies of fertilization in the green alga, Chlamydomonas, we report identification of a membrane protein on minus gametes, Minus Adhesion Receptor 1 (MAR1), that is essential for the membrane attachment with plus gametes that immediately precedes lipid bilayer merger. We show that MAR1 forms a receptor pair with previously identified receptor FUS1 on plus gametes, whose ectodomain architecture we find is identical to a sperm adhesion protein conserved throughout plant lineages. Strikingly, before fusion, MAR1 is biochemically and functionally associated with the ancient, evolutionarily conserved eukaryotic class II fusion protein HAP2 on minus gametes. Thus, the integral membrane protein MAR1 provides a molecular link between membrane adhesion and bilayer merger during fertilization in Chlamydomonas.

We previously reported that chaetoglobosin A (ChA) exhibits a great potential in the biocontrol of nematodes and pathogenic fungi. To improve the production of ChA, a CRISPR-Cas9 system was created and applied for eliminating potential competitive polyketide products. One of the polyketide synthase encoding genes, Cgpks11, which is putatively involved in the biosynthesis of chaetoglocin A, was disrupted. Cgpks11 deletion led to the overexpression of the CgcheA gene cluster, which is responsible for ChA biosynthesis, and a 1.6-fold increase of ChA. Transcription of pks-1, a melanin PKS, was simultaneously upregulated. Conversely, the transcription of genes for chaetoglocin A biosynthesis, e.g., CHGG_10646 and CHGG_10649, were significantly downregulated. The deletion also led to growth retardation and seriously impaired ascospore development. This study found a novel regulatory means on the biosynthesis of ChA by CgPKS11. CgPKS11 affects chaetoglobosin A biosynthesis, growth, and development in Chaetomium globosum.

Invasion by alien plants is frequently attributed to increased resource availabilities. Still, our understanding is mainly based on effects of single resources despite the fact that plants rely on multiple resources. How multiple resources affect success of alien plants remains largely unexplored. Here, with two common garden experiments, one in China and one in Germany, we tested whether nutrient and light availabilities affected the competitive outcomes between alien and native plants. We found that under low resource availabilities or with addition of only one type of resource aliens were not more competitive than natives. However, with a joint increase of nutrients and light intensity, aliens outcompeted natives. Our finding indicates that addition of multiple resources could greatly reduce the number of limiting factors (i.e. niche dimensionality), and that this favors the dominance of alien species. It also indicates that habitats experiencing multiple global changes might be more vulnerable to plant invasion.

Artificial light at night (ALAN) has been and still is rapidly spreading, and has become an important component of global change. Although numerous studies have tested its potential biological and ecological impacts on animals, fewer have tested its impacts on plants, and very few studies have tested whether it affects alien and native plants differently. Furthermore, common plant species, and particularly common alien species, are often found to benefit more from additional resources than rare native and rare alien species. Whether this is also the case with regard to increasing light due to ALAN is still unknown.Here, we tested how ALAN affects the performance of common and rare alien and native plants directly and indirectly via flying insects. We grew five common alien, six rare alien, five common native and four rare native plant species under four combinations of two ALAN (no ALANvsALAN) and two insect-exclusion (no exclusionvsexclusion) treatments, and compared their biomass production.We found that common plant species, irrespective of whether they are alien or native, produced significantly more biomass than rare species, particularly under ALAN. Furthermore, alien species tended to show a slightly stronger positive response to ALAN than native species (marginally significant origin × ALAN interaction,p= 0.079).Our study shows that common plant species benefited more from ALAN than rare ones. This might lead to shifts in plant diversity and vegetation composition, further propelling global biodiversity decline, when ALAN becomes more widespread. In addition, the slightly more positive response of alien species indicates that ALAN might increase the risk of alien plant invasions.

Human-mediated introduction of plant and animal species into biogeographic ranges where they did not occur before has been so pervasive globally that many ecosystems are now co-invaded by multiple alien plant and animal species. Although empirical evidence of invaders modifying recipient ecosystems to the benefit of other aliens is accumulating, these interactions remain underexplored and underrepresented in heuristic models of invasion success. Many freshwater ecosystems are co-invaded by aquatic macrophytes and mollusks and at the same time experience nutrient enrichment from various sources. However, studies are lacking that test how nutrient enrichment and co-invasion by alien herbivores and plant species can interactively affect native plant communities in aquatic habitats. To test such effects, we performed a freshwater mesocosm experiment in which we grew a synthetic native macrophyte community of three species under two levels of nutrient enrichment (enrichment vs. no-enrichment) treatment and fully crossed with two levels of competition from an invasive macrophyte Myriophyllum aquaticum (competition vs. no-competition), and two levels of herbivory by an invasive snail Pomacea canaliculata (herbivory vs. no-herbivory) treatments. Results show that herbivory by the invasive snail enhanced above-ground biomass yield of the invasive macrophyte. Moreover, the invasive herbivore preferentially fed on biomass of the native macrophytes over that of the invasive macrophyte. However, nutrient enrichment reduced above-ground biomass yield of the invasive macrophyte. Our results suggest that eutrophication of aquatic habitats that are already invaded by M. aquaticum may slow down invasive spread of the invasive macrophyte. However, herbivory by the invasive snail P. canaliculata may enhance invasive spread of M. aquaticum in the same habitats. Broadly, our study underscores the significance of considering several factors and their interaction when assessing the impact of invasive species, especially considering that many habitats experience co-invasion by plants and herbivores and simultaneously undergo varous other disturbances including nutrient enrichment.

SummaryNitrogen (N) is an essential mineral nutrient necessary for plant growth and has been considered a crucial factor influencing invasion success. Former studies mainly focused on responses of alien plants to different levels of N availability. However, in natural soils, N comes in different forms. Few experimental studies have explored responses of naturalized alien species to different N forms, and whether such responses are related to their naturalization success globally.We selected 22 common herbaceous species native to Germany that have all become naturalized and thus been introduced elsewhere in the world. We grew these species under six different N conditions that differed in the amount or form of N, and assessed their growth performance in a greenhouse experiment.We found that plants produced more biomass when grown under high N levels than under low N levels, and when N was provided in inorganic form than when provided in organic form. Neither biomass production nor promiscuity to different N forms was related to naturalization success of the species. However, the biomass response to inorganic N, relative to organic N, was stronger for the widely naturalized species than for the less widely naturalized ones.Our study shows that although the widely naturalized alien species were not more promiscuous than the less widely naturalized species, they took more advantage of the inorganic-N forms. This indicates that naturalization success might be partly driven by a species’ ability to take advantage of increased inorganic N levels.

Numerous studies have highlighted the role of nutrient availability and fluctuations therein for invasion success of alien plants. Others also highlighted the role of herbivores in invasion success. However, how herbivory and the level and fluctuations in nutrient availability interact in driving alien plant invasion into resident communities remains largely unexplored.We grew eight invasive alien species as target species in pot□mesocosms with five different synthetic native communities in a three-factorial design with two levels of nutrient availability (low vs high), two levels of nutrient fluctuations (constant vs pulsed) and two levels of herbivory (with vs without).The relative biomass production of the alien target plants decreased in response to an increase in nutrient availability, and increased in response to the presence of herbivores. Furthermore, herbivory could interact with changes in nutrient availability and nutrient fluctuations to affect the dominance of the alien target species (a marginally significant interaction; 90% CIs: [0.125, 2.712]).Our multispecies experiment indicates that herbivory could mediate the interactive effect of nutrient enrichment and variability in nutrient supply on invasion of alien plants into native communities. Therefore, we recommend that studies testing the fluctuating resources hypothesis should also consider interactive effect of other trophic levels.

Although many studies have tested the direct effects of drought on alien plant invasion, less is known about how drought affects alien plant invasion indirectly via other groups of organisms such as soil fauna. To test for such indirect effects, we grew single plant of nine naturalized alien target species in pot-mesocosms with a native community of five native grassland species under four combinations of two drought (well-watered vs drought) and two soil-fauna-inoculation (with vs without) treatments. We found that drought decreased the absolute and the relative biomass production of the alien plants, and thus reduced their competitive advantage in the native community. Drought decreased the abundance of soil fauna, particularly the soil mites, but did not affect abundance and richness of soil herbivores. Soil-fauna inoculation increased the biomass of the native plant community and thereby decreased the relative biomass production of the alien species. The increased invasion resistance due to soil fauna, however, tended (p = 0.09) to be stronger for plants growing under well-watered conditions than under drought. Our multispecies experiment thus shows that soil fauna might help native resident communities to resist alien plant invasions, but that this effect might be diminished by drought.

Simple Summary Bumblebees and honeybees are well known as the dominant and most important pollinators in natural and agricultural ecosystems. The quality characteristics of their colonies depend greatly on the reproductive ability/quality of the parents (queens and drones). Male bees, despite their exclusive reproductive role and ability to determine colony quality, have been less considered than female bees, especially bumblebees. We reviewed the current studies on environmental factors and inherent characteristics that affect the mating success and fecundity of male honeybees and bumblebees. Temperature, nutrients, pesticides, body size, weight and age affect reproduction in male bees and consequently the progeny colony quality. However, more studies, especially in male bumblebees, are still needed to address the impacts of these factors in detail to confront the requirements of agricultural pollination and declining wild bee pollinators worldwide. Abstract Bumblebees and honeybees are very important pollinators and play a vital role in agricultural and natural ecosystems. The quality of their colonies is determined by the queens and the reproductive drones of mother colonies, and mated drones transmit semen, including half of the genetic materials, to queens and enhance their fertility. Therefore, factors affecting drone fecundity will also directly affect progeny at the colony level. Here, we review environmental and bee-related factors that are closely related to drone reproductive ability. The environmental factors that mainly affect the sperm count and the viability of males include temperature, nutrients and pesticides. In addition, the inherent characteristics of male bees, such as body size, weight, age, seminal fluid proteins and proteins of the spermathecal fluid, contribute to mating success, sperm quality during long-term storage in the spermathecae and the reproductive behaviors of queens. Based on the results of previous studies, we also suggest that the effects of somatotype dimorphism in bumblebee males on sperm quality and queen fecundity and the indispensable and exploitable function of gland proteins in the fecundity of males and queens should be given more attention in further studies.

The fungal products dibenzodioxocinones promise a novel class of inhibitors against cholesterol ester transfer protein (CEPT). Knowledge as to their biosynthesis is scarce. In this report, we characterized four more dibenzodioxocinones, which along with a previously described member pestalotiollide B, delimit the dominant spectrum of secondary metabolites in P. microspora. Through mRNA-seq profiling in gα1Δ, a process that halts the production of the dibenzodioxocinones, a gene cluster harboring 21 genes including a polyketide synthase, designated as pks8, was defined. Disruption of genes in the cluster led to loss of the compounds, concluding the anticipated role in the biosynthesis of the chemicals. The biosynthetic route to dibenzodioxocinones was temporarily speculated. This study reveals the genetic basis underlying the biosynthesis of dibenzodioxocinone in fungi, and may facilitate the practice for yield improvement in the drug development arena.

The ginkgo biloba extract (GBE) nanoparticles were successfully prepared by adopting the liquid anti‐solvent precipitation (LASP) method to enhance the antioxidant activity and oral bioavailability of GBE. Under the optimum preparation conditions, the particle size of GBE nanoparticles had reached 76.90 nm. Moreover, the antioxidant activity and intestinal transmittance of GBE nanoparticles were tested before and after the simulated in vitro digestion, which were both significantly higher than that of raw GBE. Significantly, the AUC₍₀→ₜ₎ value of flavonoids and terpene lactones in GBE nanoparticles were 2.20 and 2.24 times of that in raw GBE, respectively. What cannot be ignored was that the residual amount of ethanol and n‐hexane meets the safety standards for food.

It is frequently assumed that species capable of fast nitrogen (N) acquisition under different N‐availability conditions should have a higher establishment success after their introduction into new regions. However, few experimental studies have explicitly tested this. Our multispecies experiment tested whether global naturalization success of plant species native to Central Europe is related to a high N‐acquisition ability. We selected 41 common herbaceous species native to Germany that have all become naturalized, and thus been introduced, elsewhere. Twenty‐two of these species are widely naturalized and 19 are less widely naturalized. We grew the 41 grassland species, sampled in Germany, under low and high N‐conditions in a greenhouse experiment, and assessed their N‐acquisition abilities. Although the widely naturalized species grew faster on average, they had a significantly lower N‐uptake rate than the less widely naturalized ones. The widely naturalized species, however, had a marginally significantly higher root‐mass fraction. Despite these differences, the total plant N‐content did on average not differ between the two groups of species. However, N‐addition tended to increase the total plant N‐content more for the widely naturalized species than for the less widely naturalized species. Nitroge addition also increased biomass production and N‐uptake rate, and decreased the root‐mass fraction of plants, but these responses did not differ between widely and less widely naturalized species. We conclude that although fast‐growing species tend to have a higher global naturalization success than slow‐growing species, the naturalization success of plants is not necessarily related to a high N‐acquisition ability. A plain language summary is available for this article.

Artificial light at night has rapidly increased during the last century, and could potentially affect many ecological processes, from individuals via communities to entire ecosystems. Recent research has shown that artificial light at night may not only affect the behavior of animals but also growth of plants and vegetation composition. However, it is not known yet whether artificial light at night may also affect other global change components such as plant invasions.Here, we tested how naturalized alien plants respond to artificial light at night, and particularly whether widely naturalized species differ from less‐widely naturalized species in their response to artificial light at night. We grew nine taxonomically related pairs of widely naturalized and less‐widely naturalized species alone and in competition, with native plants with and without artificial light at night.We found that in the competition treatment, artificial light at night significantly increased the total biomass production per pot, but not the biomass ratio between the naturalized alien plants and the native competitors. Interestingly, although the less‐widely naturalized species produced overall significantly less biomass than the widely naturalized species, there was a trend that the less‐widely naturalized species increased their biomass more strongly in response to artificial light at night than the widely naturalized species did (P = 0.07).Synthesis. Our study shows that although widely naturalized plants produce more biomass than less‐widely naturalized plants across different environmental conditions, they took less advantage of artificial light at night. This suggests that artificial light at night might lead to increased spread of currently less‐widely naturalized species, at least when artificial light at night continues to increase. published

Phytase is an enzyme that has the ability to release phosphorous (P) from phytate by hydrolyzing inositol-phosphate linkages. Recently, thermostable phytases have gained great consideration because the reduction in phytase activity was found when exposed to heat during feed pelleting. In this study, the effects of the granular thermostable phytase (Aspergillus niger) on growth performance and nutrient utilization of broilers were investigated. A total of 96 21-day-old Arbor Acres broilers were randomly distributed into six treatments including basal diet (control) and basal diet supplemented with 500, 1,000, 2,000, 4,000, 8,000 U of phytase/kg. In general, the metabolizable energy (ME) and the apparent and true availability of dry matter (DM), organic matter (OM), ether extract (EE), crude protein (CP), and amino acids (AA) showed both linearly (p

We investigated the effects of housing systems and dietary glucose oxidase (GOD) on the growth performance and intestinal health of Beijing You chickens (BYC). The experiment was designed as a factorial arrangement of 2 housing systems × 2 dietary treatments. Chickens were fed a basal diet or a diet with 200 U/kg GOD and were reared on the floor with deep litter or in the cages. Compared with the litter floor groups, the decreased average daily feed intake of 1 to 42 d, decreased feed conversion ratio (FCR), improved average daily gain of 42 to 77 d, and the whole period were identified in the cage rearing groups (P < 0.05). The FCR of 42 to 77 d and the whole period, the 42-d ileal pH, and 77-d jejunal and ileal pH decreased with the supplement of GOD (P < 0.05). Additionally, 16S rRNA gene of ileum contents was sequenced by high-throughput sequencing. Sequencing data indicated that the Firmicutes phylum of 42 d and the Bacteroidetes phylum were significantly higher in the litter group with GOD supplement (P < 0.05). The jejunal Occludin, Mucin-2 mRNA expression levels were higher in the litter floor groups than those in the cage rearing groups on 42 d (P < 0.05). The Mucin-2 and TNF-α mRNA expression levels increased with cage rearing on 77 d (P < 0.05). The Occludin and TLR-4 mRNA expression levels increased with the supplementation of GOD on 77 d (P < 0.05). Moreover, the upregulation effects of Occludin and ZO-1 mRNA expression levels were more obvious in the litter floor group fed with GOD diet on 77 d (P < 0.05). The serum endotoxin content of 42-day-old cage rearing groups were higher than that of the litter floor groups, and the serum endotoxin content significantly decreased with the supplement of GOD on 77 d. The results indicated that the litter floor systems were beneficial to the development of intestinal barrier junction in the early stage, but the cage systems were more conducive to the growth performance of BYC. The dietary GOD could inhibit the harmful bacteria and promote the beneficial bacteria, which might be related to the improvement of the growth performance and intestinal barrier function.

International audience; China has many habitats supporting a wide diversity of bumblebees, some species of which are limited in distribution to the Tibet Plateau. The high-altitude Tibet Plateau, which has low air density as well as extremely low temperatures, strains the energy requirements for flight in most insects. However, high-altitude bumblebees have adapted to the harsh conditions of this type of habitat. Bumblebees are a particular group of insect pollinators that exclusively utilize carbohydrates from flowers for energy to sustain flight. Here, gene expression was compared between low-altitude species and Bombus longipennis, and the genes upregulated in B. longipennis were involved in aerobic metabolism, such as the oxidative phosphorylation and citric acid cycle (TCA cycle) pathways. Furthermore, a conjoint analysis of the transcriptomes of six bumblebee species from the high-altitude Tibet Plateau and two bumblebee species from the low-altitude North China Plain showed that 19 genes were commonly upregulated in high-altitude species. Among these 19 commonly upregulated genes, Pfk1 was enriched in multiple glycometabolic pathways, which are the main energy pathways in bees; this upregulation enhanced the aerobic and anaerobic glycolysis processes to produce more ATP molecules to supply energy for high-altitude bumblebee flight under severe cold conditions. In addition, glycolysis was enhanced by two other genes, Rac1 and AAC2. Relative quantitative real-time PCR was used to verify that the three genes Pfk1, Rac1, and AAC2 were upregulated in the six main bumblebee species inhabiting the Tibet Plateau.

Bombus pyrosoma is one of the most abundant bumblebee species in China, with a distribution range of very varied geomorphology and vegetation, which makes it an ideal pollinator species for research into high-altitude adaptation. Here, we sequenced and assembled transcriptomes of B. pyrosoma from the low-altitude North China Plain and the high-altitude Tibet Plateau. Subsequent comparative analysis of de novo transcriptomes from the high- and low-altitude groups identified 675 common upregulated genes (DEGs) in the high-altitude B. pyrosoma. These genes were enriched in metabolic pathways and corresponded to enzyme activities involved in energy metabolism. Furthermore, according to joint analysis with comparative metabolomics, we suggest that the metabolism of coenzyme A (CoA) and the metabolism and transport of energy resources contribute to the adaptation of high-altitude B. pyrosoma. Meanwhile, we found many common upregulated genes enriched in the Toll and immune deficiency (Imd)signaling pathways that act as important immune defenses in insects, and hypoxia and cold temperatures could induce the upregulation of immune genes in insects. Therefore, we suppose that the Toll and Imd signaling pathways also participated in the high-altitude adaptation of B. pyrosoma. Like other organisms, we suggest that the high-altitude adaptation of B. pyrosoma is controlled by diverse mechanisms.

A conserved open reading frame, dps, is described in Pestalotiopsis microspora, sharing a remarkable similarity with fungal diterpene synthases whose function is less studied. Loss-of-function approach manifested that dps was necessary for the growth and the development of the fungus. A deletion strain, dpsΔ, showed a fundamental retardation in growth, which could deliberately be restored by the addition of exogenous sterols to the media. Gas chromatography–mass spectrometry analysis confirmed the loss of the ability to produce certain sterols. Thus, the tolerance and the resistance of dpsΔ to several stress conditions were impaired. Secondary metabolites, such as the polyketide derivative dibenzodioxocinones, were significantly diminished. At the molecular level, the deletion of dps even affected the expression of genes in the mevalonate pathway. This report adds knowledge about fungal diterpene synthases in Pestalitiopsis microspora.

Glutamylation, introduced by TTLL enzymes, is the most abundant modification of brain tubulin. Essential effector proteins read the tubulin glutamylation pattern, and its misregulation causes neurodegeneration. TTLL glutamylases posttranslationally add glutamates to internal glutamates in tubulin C-terminal tails (branch initiation, through an isopeptide bond), and additional glutamates can extend these (elongation). TTLLs are thought to specialize for initiation or elongation, but the mechanistic basis for regioselectivity is unknown. We present cocrystal structures of murine TTLL6 bound to tetrahedral intermediate analogs that delineate key active-site residues that make this an elongase. We show that TTLL4 is exclusively an initiase, and through combined structural and phylogenetic analyses, engineer TTLL6 into a branch-initiating enzyme. TTLL glycylases add glycines posttranslationally to internal glutamates, and we find that the same active-site residues discriminate between initiase and elongase glycylases. These active-site specializations of TTLL glutamylases and glycylases ultimately yield the chemical complexity of cellular microtubules.

Allelopathy (i.e. chemical interactions between plants) is known to affect individual performance, community structure and plant invasions. Yet, a quantitative synthesis is lacking. Here, we performed a meta-analysis of 384 studies that measured allelopathic effects of one species (allelopathy plant) on another species or itself (test plant). Overall, allelopathy reduced plant performance by 25%, but the variation in allelopathy was high. The type of method affected the allelopathic effect: compared to leachates, allelopathy was more negative when residues of allelopathy plants were applied, and less negative when soil conditioned by allelopathy plants was applied. The negative effects of allelopathy diminished with study duration, and increased with concentrations of leachates or residues. Although allelopathy was not significantly related to lifespan, life form or domestication of the interacting plants, it became more negative with increasing phylogenetic distance. Moreover, native plants suffered more from leachates of naturalised alien plants than from leachates of other native plants. Our synthesis reveals that allelopathy could contribute to success of alien plants. The negative relationship between phylogenetic distance and allelopathy indicates that allelopathy might contribute to coexistence of closely related species (i.e. convergence) or dominance of single species. published

Allelopathy (i.e. chemical interactions between plants) is known to affect individual performance, community structure and plant invasions. Yet, a quantitative synthesis is lacking. We performed a meta-analysis of 385 studies that measured allelopathic effects of one species (allelopathy plant) on another species or itself (test plant). Overall, allelopathy reduced plant performance by 25%, but the variation in allelopathy was high. Type of method affected allelopathic effect. Compared to leachates, allelopathy was more negative when residues of allelopathy plants were applied, and less negative when soil conditioned by allelopathy plants was applied. The negative effects of allelopathy diminished with study duration, and increased with concentrations of leachates or residues. Although allelopathy was not significantly related to life span, life form and domestication of the interacting plants, it became more negative with increasing phylogenetic distance. Moreover, native plants suffered more negative effects from leachates of naturalized alien plants than of other native plants. Our synthesis reveals that allelopathy could contribute to success of alien plants. The negative relationship between phylogenetic distance and allelopathy indicates that allelopathy might drive coexistence of close-related species (i.e. convergence) or dominance of single species.

Peptidoglycan recognition proteins (PGRPs) play an important role in the defense against invading microbes via the recognition of the immunogenic substance peptidoglycan (PGN). Bees possess fewer PGRPs than Drosophila melanogaster and Anopheles gambiae but retain two important immune pathways, the Toll pathway and the Imd pathway, which can be triggered by the recognition of Dap-type PGN by PGRP-LCx with the assistance of PGRP-LCa in Drosophila. There are three isoforms of PGRP-LC including PGRP-LCx, PGRP-LCa and PGRP-LCy in Drosophila. Our previous study showed that a single PGRP-LC exists in bumblebees. In this present study, we prove that the bumblebee Bombus lantschouensis PGRP-LC (Bl-PGRP-LC) can respond to an infection with Gram-negative bacterium Escherichia coli through binding to the Dap-type PGNs directly, and that E. coli infection induces the quick and strong upregulation of PGRP-LC, abaecin and defensin. Moreover, the Bl-PGRP-LC exhibits a very strong affinity for the Dap-type PGN, much stronger than the affinity exhibited by the PGRP-LC from the more eusocial honeybee Apis mellifera (Am-PGRP-LC). In addition, mutagenesis experiments showed that the residue His390 is the anchor residue for the binding to the Dap-type PGN and forms a hydrogen bond with MurNAc rather than meso-Dap, which interacts with the anchor residue Arg413 of PGRP-LCx in Drosophila. Therefore, bumblebee PGRP-LC possesses exclusive characteristics for the immune response among insect PGRPs.

Sixty year ago, Elton proposed that diverse communities are more resistant to biological invasion. However, still little is known about which processes could drive this diversity-invasibility relationship. Here we examined whether plant-soil feedback on alien invaders is more negative when the soil originates from multiple native species. We trained soils with five individually grown native species, and used amplicon sequencing to analyze the resulting bacterial and fungal soil communities. We mixed the soils to create trained soils from one, two or four native species. We then grew four alien species separately on these differently trained soils. In the soil-conditioning phase, the five native species built species-specific bacterial and fungal communities in their rhizospheres. In the test phase, it did not matter whether the soil had been trained by one or two native species. However, the alien species achieved 11.7% less aboveground biomass when grown on soils trained by four native species than on soils trained by two native species. Our results showed for the first time, that plant-soil feedback could be a process that contributes to the negative relationship between diversity and invasibility.

While most alien species fail to establish, some invade native communities and become widespread. Many of these communities have been invaded by multiple aliens, suggesting that aliens may cause invasional meltdowns. Here, we tested whether and how a third plant species affects the competitive outcome between alien and native plants through its soil legacy. We first conditioned soil with one of ten species (six natives and four aliens) or without plants. Then, we grew on these 11 soils, five aliens and five natives without competition, and with intra- or interspecific competition (all pairwise alien-native combinations). We found that aliens were not more competitive than natives when grown on soil conditioned by other natives or on non-conditioned soil. However, aliens were more competitive than natives on soil conditioned by other aliens. Although soil conditioning rarely affected the strength of competition between later plants, soil conditioned by aliens changed the competitive outcomes by affecting growth of aliens less negatively than that of natives. Microbiome analysis confirmed this finding by showing that the soil-legacy effects of one species on later species were less negative when their fungal endophyte communities were less similar; and that fungal endophyte communities were less similar between two aliens than between aliens and natives. Our study suggests that coexistence between aliens and natives is less likely with more alien species. Such invasional meltdown is likely mediated by spill-over of fungal endophytes, some of which are pathogenic.

Lethal infections by strains of the highly-pathogenic avian influenza virus (HPAIV) H5N1 pose serious threats to both the poultry industry and public health worldwide. A lack of confirmed HPAIV epitopes recognized by cytotoxic T lymphocytes (CTLs) has hindered the utilization of CD8(+) T-cell–mediated immunity and has precluded the development of effectively diversified epitope-based vaccination approaches. In particular, an HPAIV H5N1 CTL-recognized epitope based on the peptide MHC-I–β2m (pMHC-I) complex has not yet been designed. Here, screening a collection of selected peptides of several HPAIV strains against a specific pathogen-free pMHC-I (pBF2*1501), we identified a highly-conserved HPAIV H5N1 CTL epitope, named HPAIV–PA(123–130). We determined the structure of the BF2*1501–PA(123–130) complex at 2.1 Å resolution to elucidate the molecular mechanisms of a preferential presentation of the highly-conserved PA(123–130) epitope in the chicken B15 lineage. Conformational characteristics of the PA(123–130) epitope with a protruding Tyr-7 residue indicated that this epitope has great potential to be recognized by specific TCRs. Moreover, significantly increased numbers of CD8(+) T cells specific for the HPAIV–PA(123–130) epitope in peptide-immunized chickens indicated that a repertoire of CD8(+) T cells can specifically respond to this epitope. We anticipate that the identification and structural characterization of the PA(123–130) epitope reported here could enable further studies of CTL immunity against HPAIV H5N1. Such studies may aid in the development of vaccine development strategies using well-conserved internal viral antigens in chickens.

While most alien species fail to establish, some invade native communities and become widespread. Our understanding of invasion success is derived mainly from pairwise interactions between aliens and natives, while interactions among more than two species remain largely unexplored. Here, we experimentally tested whether and how a third plant species, either native or alien, affected the competitive outcomes between alien and native plants through its soil legacy. We first conditioned soil with one of ten species (six natives and four aliens) or without plants. We then grew on these 11 soils five aliens and five natives without competition, or with intra- or interspecific competition. We found that aliens were not more competitive than natives when grown on soil conditioned by other natives or on non-conditioned soil. However, aliens were more competitive than natives on soil conditioned by other aliens (that is, invasional meltdown). Soil conditioning did not change competitive outcomes by affecting the strength of competition between later plants. Instead, soil conditioned by aliens pushed competitive outcomes towards later aliens by affecting the growth of aliens less negatively than that of natives. Microbiome analysis verified this finding, as we showed that the soil-legacy effects of a species on later species were less negative when their fungal endophyte communities were less similar, and that fungal endophyte communities were less similar between two aliens than between aliens and natives. Our study reveals invasional meltdown in multispecies communities and identifies soil microorganisms as a driver of the invasion success of alien plants. published

Sixty year ago, Charles Elton posed that species-rich communities should be more resistant to biological invasion. However, still little is known about which processes could drive the diversity-invasibility relationship. Here we examined whether soil-microbes-mediated apparent competition on alien invaders is more negative when the soil originates from multiple native species. We trained soils with five individually grown native species, and used amplicon sequencing to analyze the resulting bacterial and fungal soil communities. We mixed the soils to create trained soils from one, two or four native species. We then grew four alien species separately on these differently trained soils. In the soil-conditioning phase, the five native species built species-specific bacterial and fungal communities in their rhizospheres. In the test phase, it did not matter for biomass of alien plants whether the soil had been trained by one or two native species. However, the alien species achieved 11.7% (95% CI: 3.7% ~ 20.1%) less aboveground biomass when grown on soils trained by four native species than on soils trained by two native species. Our results revealed soil-microbes-mediated apparent competition as a mechanism underlying the negative relationship between diversity and invasibility. published

Arbor Acre (AA) broilers were used as the research object to investigate whether glucose oxidase (GOD) has preventive and relieving effects on necrotic enteritis. The experiment was designed as a factorial arrangement of 2 dietary treatments × 2 infection states. Chickens were fed a basal diet or a diet with 150 U/kg GOD, and were challenged with Clostridium perfringens (Cp) or sterile culture medium. In our study, Cp challenge led to intestinal injury, as evidenced by reducing the average daily gain and the average daily feed intake of AA broilers of 14 to 21 d (P < 0.05), increasing the intestinal jejunal lesion score (P < 0.05), reducing the jejunal villi height and villi height/crypt depth (P < 0.05), upregulating the mRNA expression levels jejunal IFN-γ (P < 0.05). The dietary GOD had no significant effects on the growth performance of each growth period, but significantly decreased the ileal pH, increased the height of villi and the ratio of villi height to crypt depth (P < 0.05) and the expression levels of Occludin and Zonula occludens-1 (ZO-1) at d 21. Moreover, dietary GOD and the Cp challenge significantly altered the composition of 21-d ileal microbiota. The Cp challenge decreased the relative abundance of genus Lactobacillus (P = 0.057), and increased the relative abundance of genus Romboutsia (P < 0.05) and genus Veillonella (P = 0.088). The dietary GOD tended to increase the relative abundance of genus Helicobacter (P = 0.066) and decrease the relative abundance of genus Streptococcus (P = 0.071). This study has shown that the supplementation of GOD could promote the integrity of intestinal barrier and the balance of ileal microbiota, but the effects of GOD on NE broilers and its application in actual production need to be further confirmed.

Background The canonical heterotrimeric G protein-cAMP/PKA pathway regulates numerous cellular processes in filamentous fungi. Chaetomium globosum, a saprophytic fungus, is known for producing many secondary metabolites, including cytotoxic chaetoglobosin A (ChA), as well as abundant cellulase and xylanase. Results Here we report on the functional characterization of this signaling pathway in C. globosum. We blocked the pathway by knocking down the putative Gα-encoding gene gna1 (in the pG14 mutant). This led to impaired cellulase production and significantly decreased transcription of the major cellulase and xylanase genes. Almost all the glycohydrolase family genes involved in cellulose degradation were downregulated, including the major cellulase genes, cel7a, cel6a, egl1, and egl2. Importantly, the expression of transcription factors was also found to be regulated by gna1, especially Ace1, Clr1/2 and Hap2/3/5 complex. Additionally, carbon metabolic processes including the starch and sucrose metabolism pathway were substantially diminished, as evidenced by RNA-Seq profiling and quantitative reverse transcription (qRT)-PCR. Interestingly, these defects could be restored by simultaneous knockdown of the pkaR gene encoding the regulatory subunit of cAMP-dependent PKA (in the pGP6 mutant) or supplement of the cAMP analog, 8-Br-cAMP. Moreover, the Gα-cAMP/PKA pathway regulating cellulase production is modulated by environmental signals including carbon sources and light, in which VelB/VeA/LaeA complex and ENVOY probably work as downstream effectors. Conclusion These results revealed, for the first time, the positive role of the heterotrimeric Gα-cAMP/PKA pathway in the regulation of cellulase and xylanase utilization in C. globosum. Electronic supplementary material The online version of this article (10.1186/s12934-018-1008-6) contains supplementary material, which is available to authorized users.

1.It is frequently thought that global environmental changes, and especially the concomitant changes in environmental variability, could further increase the success of invasive species in native resident communities. However, very few studies explicitly tested this, and it remains unknown whether invasive and non‐invasive alien species respond differently to resource fluctuations in resident communities.2.We grew ten invasive and ten non‐invasive species as target species in pot‐mesocosms with four different synthetic native resident communities under six nutrient treatments differing in overall nutrient availability and temporal fluctuations in nutrient supply (constant low, constant high, gradual increasing, gradual decreasing, single large pulse, multiple smaller pulses). With the exception of plants in the constant low treatment, the plants were supplied the same total amount of nutrients during the experiment. We tested whether high nutrient availability and fluctuations in nutrient supply increased performance of both invasive and non‐invasive alien plants within native resident communities, and whether invasive ones benefited more than non‐invasive ones.3.We found that the increase in biomass in response to nutrient addition was stronger for invasive than for non‐invasive alien species. However, as the native competitors benefited even more from nutrient addition, the relative biomass of the alien target plant species, particularly the non‐invasive ones, decreased. When the nutrient supply gradually increased, biomass of alien targets as well as native competitors decreased compared to the plants in the constant nutrient supply treatment. Surprisingly, when nutrients were supplied as a single large pulse, the absolute and relative biomass of the alien target plants decreased. The reduction in relative biomass was even stronger for invasive than for non‐invasive alien species, and a similar pattern was found when nutrients were supplied as multiple smaller pulses.4.Our results confirm previous findings that invasive alien species benefit more from nutrient addition than non‐invasive alien species. However, in contrast to previous findings, our results suggest that nutrient fluctuations can suppress biomass of alien plants relative to that of natives, at least when the natives are themselves very successful, common species. published

Peptidoglycan recognition protein SA (PGRP-SA) is a key pattern recognition receptor in the insect innate immune system. PGRP-SA can bind to bacterial PGN and activate the Toll pathway, which triggers the expression and release of antimicrobial peptides to prevent bacterial infection. Here, we report the first structure of Apis mellifera PGRP-SA from Hymenoptera at 1.86 A resolution. The overall architecture of Am-PGRP-SA was similar to the Drosophila PGRP-SA; however, the residues involved in PGN binding groove were not conserved, and the binding pocket was narrower. This structure gives insight into PGN binding characteristics in honeybees.

Background: HOX transcript antisense RNA (HOTAIR) is a long non-coding RNA (lncRNA) widely involved in the progression of numerous malignancies. Whereas, the potential molecular mechanism of HOTAIR involved in cervical cancer progression is still needed to be elaborated. Methods: The expression of HOTAIR and miR-143-3p were detected in cervical cancer tissues and cells by qRT-PCR. MTT and flow cytometry analysis were performed to measure cell proliferation and apoptosis. Bioinformatics, Dual-Luciferase reporter and RIP were used to analyze the possible correlation between HOTAIR, miR-143-3p and BCL2. The expression of Bax and BCL2 was detected by western blot. Mice xenograft model was established to confirm the role of HOTAIR on tumor growth in vivo. Results: HOTAIR expression was elevated while miR-143-3p expression was reduced in cervical cancer tissues and cell lines. HOTAIR knockdown suppressed proliferation and enhanced apoptosis in cervical cancer cells. Moreover, HOTAIR could function as a sponge for miR-143-3p. The inhibitory effect of HOTAIR knockdown on cervical cancer cells growth was abolished following decrease of miR-143-3p expression. Furthermore, HOTAIR promoted BCL2 expression by modulating miR-143-3p. BCL2 overexpression attenuated the tumor-suppressive effect of miR-143-3p in cervical cancer. Finally, the carcinogenicity of HOTAIR was validated in mice. Conclusions: HOTAIR promoted cervical cancer cell growth by modulating BCL2 via miR-143-3p, hinting a novel regulatory mechanism and potential therapeutic target in cervical cancer.

Nitrogen (N) deposition and land use are likely to alter plant phenology, with subsequent effects on community structure and ecosystem function. Phenological responses of three early-flowering species, Anemone trullifolia var. linearis, Caltha scaposa, and Trollius farreri to N addition and hay mowing were investigated in a Tibetan alpine meadow over three years. N addition significantly delayed the first flowering time of A. trullifolia var. linearis (by 11.7 days) and C. scaposa (by 11.1 days), but did not affect that of T. farreri. Mowing prolonged the first flowering time and first fruiting time by 4.7 and 7.4 days across all three species. Significant interactions between mowing and N addition on reproductive phenology characteristics were detected. Mowing induced changes in the first and last flowering times were 6.5 and 4.3 days earlier in the N addition plots than those in the N non-addition plots. The changes in reproductive time were mainly attributed to the variations in standing litter in each treatment, i.e. reproductive phenology (timing of flowering and fruiting) was positively associated with litter accumulation. Our results indicate that N deposition and land use can affect plant phenology by changing the accumulation of standing litter in Tibetan alpine meadows.

For the conservation of wild pollinators, instead of surveying the whole community, one or more indicator species can be used as monitoring targets for long-term conservation. China, the richest country in terms of bumblebee species with 125 species, was selected here to investigate the indicator species of the different biogeographic regions of bumblebees. Four principal biogeographic regions of bumblebee species, i.e., South China, North-Northeast China (North China), the Mongolian Plateau and surrounding mountains (Mongolian Plateau) and the Tibetan Plateau and surrounding mountains (Tibetan Plateau), were revealed by Ward's agglomerative cluster analysis. The role of climatic factors in defining the biogeographic regions was found to be greater than those of topographical factors and their joint effects. We found that 14, 13, 12 and 12 species were associated with the regions of South China, North China, the Mongolian Plateau and the Tibetan Plateau, respectively. In addition, among these species, seven (Bombus atripes, B. bicoloratus, B. breviceps, B. eximius, B. flavescens, B. montivagus and B. trifasciatus), five (B. deuteronymus, B. patagiatus, B. pseudobaicalensis, B. tricornis and B. ussurensis), ten (B. armeniacus, B. confusus, B. cryptarum, B. cullumanus, B. hortorum, B. muscorum, B. ruderarius, B. soroeensis, B. subterraneus and B. terrestris) and four species (B. kashmirensis, B. personatus, B. rufofasciatus and B. waltoni) were identified as important indicator species for South China, North China, the Mongolian Plateau and the Tibetan Plateau, respectively. Furthermore, we identified specific areas for targeted bumblebee diversity monitoring in each region. This study highlights the bioregionalization and the identification of indicator species of bumblebee pollinators for long-term monitoring in conservation.

C1q contains three globular domains (C1qgD) that are the key functional component of the classical complement system. C1qgD can interact with important immune molecules, including IgG and C-reactive protein (CRP) to form defense systems to protect animals. Here, the first non-mammalian structure, zebrafish C1qA globular domain (Dare-C1qAgD) was solved. Although the overall architecture of Dare-C1qAgD is similar to human C1qA, residues involved in C1qBgD, C1qCgD, and CRP binding are somewhat different while residues involved in IgG binding are not present in zebrafish. The structure gives insight into how human and fish C1qA evolved from an ancestral protein.

The lack of a peptide-swine leukocyte antigen class I (pSLA I) complex structure presents difficulties for the study of swine cytotoxic T lymphocyte (CTL) immunity and molecule vaccine development to eliminate important swine viral diseases, such as influenza A virus (IAV). Here, after cloning and comparing 28 SLA I allelic genes from Chinese Heishan pigs, pSLA-3*hs0202 was crystalized and solved. SLA-3*hs0202 binding with sβ2m and a KMNTQFTAV (hemagglutinin [HA]-KMN9) peptide from the 2009 pandemic swine H1N1 strain clearly displayed two distinct conformations with HA-KMN9 peptides in the structures, which are believed to be beneficial to stimulate a broad spectrum of CTL immune responses. Notably, we found that different HA-KMN9 conformations are caused, not only by the flexibility of the side chains of residues in the peptide-binding groove (PBG), but also by the skewing of α1 and α2 helixes forming the PBG. In addition, alanine scanning and circular-dichroism (CD) spectra confirmed that the B, D, and F pockets play critical biochemical roles in determining the peptide-binding motif of SLA-3*hs0202. Based on biochemical parameters and comparisons to similar pockets in other known major histocompatibility complex class I (MHC-I) structures, the fundamental motif for SLA-3*hs0202 was determined to be X-(M/A/R)-(N/Q/R/F)-X-X-X-X-X-(V/I) by refolding in vitro and multiple mutant peptides. Finally, 28 SLA-3*hs0202-restricted epitope candidates were identified from important IAV strains, and two of them have been found in humans as HLA-A*0201-specific IAV epitopes. Structural and biochemical illumination of pSLA-3*hs0202 can benefit vaccine development to control IAV in swine. IMPORTANCE We crystalized and solved the first SLA-3 structure, SLA-3*hs0202, and found that it could present the same IAV peptide with two distinct conformations. Unlike previous findings showing that variable peptide conformations are caused only by the flexibility of the side chains in the groove, the skewing of the α1 and α2 helixes is important in the different peptide conformations in SLA-3*hs0202. We also determined the fundamental motif for SLA-3*hs0202 to be X-(M/A/R)-(N/Q/R/F)-X-X-X-X-X-(V/I) based on a series of structural and biochemical analyses, and 28 SLA-3*hs0202-restricted epitope candidates were identified from important IAV strains. We believe our structure and analyses of pSLA-3*hs0202 can benefit vaccine development to control IAV in swine.

MHC class I (MHC I)–restricted virus-specific CTLs are implicated as critical components in the control of this naturally occurring lentivirus and in the protective immune response to the successfully applied attenuated equine infectious anemia virus vaccine in the horse. Nevertheless, the structural basis for how the equine MHC I presents epitope peptides remains unknown. In this study, we investigated the binding of several equine infectious anemia virus–derived epitope peptides by the ability to refold recombinant molecules and by thermal stability, and then by determining the x-ray structure of five peptide–MHC I complexes: equine MHC class I allele (Eqca)-N*00602/Env-RW12, Eqca-N*00602/Gag-GW12, Eqca-N*00602/Rev-QW11, Eqca-N*00602/Gag-CF9, and Eqca-N*00601/Gag-GW12. Although Eqca-N*00601 and Eqca-N*00602 differ by a single amino acid, Eqca-N*00601 exhibited a drastically different peptide presentation when binding a similar CTL epitope, Gag-GW12; the result makes the previously reported function clear to be non–cross-recognition between these two alleles. The structures plus Eqca-N*00602 complexed with a 9-mer peptide are particularly noteworthy in that we illuminated differences in apparent flexibility in the center of the epitope peptides for the complexes with Gag-GW12 as compared with Env-RW12, and a strict selection of epitope peptides with normal length. The featured preferences and unconventional presentations of long peptides by equine MHC I molecules provide structural bases to explain the exceptional anti-lentivirus immunity in the horse. We think that the beneficial reference points could serve as an initial platform for other human or animal lentiviruses.

Sphingomyelin phosphodiesterase (SMPD) is a hydrolase that plays a major role in metabolic reactions involving sphingomyelin. Here, we describe an analysis of the cDNA sequence and gene structure of SMPD in bumblebee (Bombus lantschouensis). The expression of SMPD in different tissues and at different developmental stages and reproductive statuses was examined by real-time polymerase chain reaction (PCR). The results showed that the SMPD cDNA has a length of 2000 bp and contains an open reading frame (ORF) of 1,801 nucleotides that encodes a polypeptide of 599 amino acids. The full-length SMPD gene is 4228 bp and contains eight exons and seven introns. A comparative analysis revealed that the SMPD gene sequence in B. lantschouensis shares high sequence identity with those in other Bombus species. The SMPD gene is expressed broadly in various tissues and presents higher transcript levels in the ovary, midgut, and epidermis and thoracic tissues. Among the different developmental stages, the highest expression of SMPD was detected at the Pw pupal stage (pupae with an unpigmented body cuticle and white eyes), and the expression of this gene decreased from the Pp (pupae with pink eyes) to the Pdd (dark-eye pupae with a dark-pigmented cuticle) stages. In addition, SMPD expression was significantly upregulated after female egg laying. In conclusion, our results show that the bumblebee SMPD gene might play a key role at the Pw developmental stage and in female oviposition.

Adipokinetic hormone receptor (AKHR) was regarded as the crucial regulator of lipid consuming, but now has been renewed as a pluripotent neuropeptide G protein-coupled receptor. It has been identified in all sequenced bee genomes from the solitary to the eusocial. In the current study, we try to clarify the transitions of AKHR on lipid utilization and other potential functions from solitary to eusocial bees. The results showed that the AKHRs were divided into different groups based on their social complexity approximately. Nevertheless, the critical motifs and tertiary structures were highly conserved. As to the post-translational modifications, the eusocial possessed more phosphorylation residues and modification patterns, which might be due to the necessity of more diverse functions. These results suggest that AKHRs are highly conserved on both primary motifs and tertiary structures, but more flexible on posttranslational modifications so as to accommodate to more complicated eusocial life.

The peptidoglycan recognition protein SAs (PGRP-SAs) from Bombus ignitus (Bi-PGRP-SA), Apis mellifera (Am-PGRP-SA), and Megachile rotundata PGRP-SA (Mr-PGRP-SA) exhibit an intrinsic ability to preferentially bind to Dap-type peptidoglycan (PGN) from Bacillus subtilis rather than Lys-type PGN from Micrococcus luteus. This ability is more analogous to the binding exhibited by PGRP-LCx and PGRP-SD than to that exhibited by PGRP-SA in Drosophila. Moreover, Bi-PGRP-SA and Am-PGRP-SA share greater sequence identity with Drosophila PGRP-LCx than with PGRP-SD and retain several conserved contact residues, including His37/His38, His60/His61, Trp66/Trp67, Ala150/Ala151, and Thr151/Thr152. However, the corresponding contact residue Arg85 is not a major anchor residue in bees (e.g., bumblebees, honeybees, and leaf-cutting bees), and an in silico analysis indicated that the residues Thr151/Thr152 and Ser153/Ser154 of Bi-PGRP-SA and Am-PGRP-SA are deduced to be anchor residues. In addition, the nonconserved residues Asp67 in Bi-PGRP-SA and Mr-PGRP-SA and His68 in Am-PGRP-SA are deduced to be involved in the binding to Dap-type PGNs in bumblebees, honeybees, and leaf-cutting bees. We conclude that the structures and specificities of PGRP-SAs in bees are more analogous to those of PGRP-LCx than to those of Drosophila PGRP-SA. This phenomenon might be explained by the fact that the evolutionary clade of Hymenoptera is more ancient than that of Diptera.

Cell-fate decisions are central to the survival and development of both uni- and multicellular organisms. It remains unclear when and to what degree cells can decide on future fates prior to commitment. This uncertainty stems from experimental and theoretical limitations in measuring and integrating multiple signals at the single-cell level during a decision process. Here, we combine six-color live-cell imaging with the Bayesian method of statistical evidence to study the meiosis/quiescence decision in budding yeast. Integration of multiple upstream metabolic signals predicts individual cell fates with high probability well before commitment. Cells "decide" their fates before birth, well before the activation of pathways characteristic of downstream cell fates. This decision, which remains stable through several cell cycles, occurs when multiple metabolic parameters simultaneously cross cell-fate-specific thresholds. Taken together, our results show that cells can decide their future fates long before commitment mechanisms are activated.