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[Display omitted] • Fourteen natural compounds including two new compounds were isolated from P. hastata. • All the compounds were investigated for α -glucosidase inhibitory activity in vitro. • Compound 11 acts as a noncompetitive inhibitor to α -glucosidase. A phytochemical investigation of Phymatopteris hastata led to the isolation of fourteen natural compounds, including a novel protocatechuic acid methyl ester, [protocatechuic acid methyl ester-4- O -(6′- O -protocatechuoyl)- β - d -glucopyranoside, 1 ], and one enantiomeric pair of new dihydroflavones (2a/2b), together with twelve known compounds (3 ∼ 14). The structures of the new compounds were elucidated following a comprehensive analysis of spectroscopic data from HR-ESI-MS, 1D and 2D NMR, and optical rotatory dispersion (ORD), as well as acidic hydrolysis. Compounds 1 , 2 , 4 , 7 , 9 , 10 , 12 , and 13 were isolated from P. hastata for the first time. All compounds isolated from P. hastata were investigated for their α-glucosidase inhibitory activity in vitro. Compound 11 showed a significant α -glucosidase inhibitory activity (IC 50 value of 88 ± 3.6 μg/mL) and acted as a noncompetitive inhibitor. [ABSTRACT FROM AUTHOR]

• This study demonstrates that the Muscovy duck reovirus (MDRV) p10.8 protein is one of many viral non-structural proteins that induces both cell cycle arrest and apoptosis. • Our results suggest that p10.8-induced apoptosis in cultured cells occurs by the nucleoporin Tpr/p53-dependent and Fas/caspase 8-mediated pathways. • Cdc20 is required for the Muscovy duck reovirus p10.8-induced cell cycle arrest and apoptosis. • Molecular chaperone CCT2 and CCT5 are required for stabilization of Cdc20 for p10.8-mediated both cell cycle arrest and apoptosis. This study demonstrates that the Muscovy duck reovirus (MDRV) p10.8 protein is one of many viral non-structural proteins that induces both cell cycle arrest and apoptosis. The p10.8 but not σC is a nuclear targeting protein that shuttles between the nucleus and the cytoplasm. Our results reveal that p10.8-induced apoptosis in cultured cells occurs by the nucleoporin Tpr/p53-dependent and Fas/caspase 8-mediated pathways. Furthermore, a compelling finding from this study is that the p10.8 and σC proteins of MDRV facilitate CDK2 and CDK4 degradation via the ubiquitin-proteasome pathway. We found that depletion of Cdc20 reversed the p10.8- and σC- mediated CDK4 degradation and p10.8-induced apoptosis, suggesting that Cdc20 plays a critical role in modulating p10.8-mediated cell cycle and apoptosis. Furthermore, we found that depletion of chaperonin-containing tailless complex polypeptide 1 (CCT) 2 and CCT5 reduced the level of Cdc20 and reversed the p10.8- and σC-mediated CDK4 degradation and p10.8-induced apoptosis, indicating that molecular chaperone CCT2 and CCT5 are required for stabilization of Ccd20 for mediating both cell cycle arrest and apoptosis. This study provides mechanistic insights into how p10.8 induces both cell cycle arrest and apoptosis. [ABSTRACT FROM AUTHOR]

Highlights • MDRV infection induces ER stress in DF-1 cells and ducking livers. • Severe ER stress-induced by MDRV leads to apoptosis. • The MDRV p10.8 protein disassociates the Bip/IRE1 complex and increases the phosphorylated form of IRE1 to activate XBP1. • The MDRV p10.8 protein induces ER stress, resulting in apoptosis via the Bip/IRE1/XBP1 pathway. Abstract In the present study, the mechanisms underlying Muscovy duck reovirus (MDRV) p10.8 protein-induced ER stress and apoptosis in DF-1 cells and Muscovy duckling hepatic tissues were explored. On the fifth day post-infection, an increase in the mRNA levels of binding immunoglobulin protein (Bip) and X-box binding protein (XBP1), activation of XBP1/s, and an increase in percentage of apoptotic cells were observed in Muscovy duckling livers. The use of ER stress inducer Tunicamycin and ER stress inhibitor Tauroursodeoxycholic acid demonstrated that MDRV induces apoptosis via ER stress, leading to apoptosis. The use of Tunicamycin increased viral protein synthesis while Tauroursodeoxycholic acid reduced viral protein synthesis, suggesting that MDRV induces ER stress benefiting virus replication. The MDRV p10.8 is the major protein to induce ER stress and apoptosis. We found that p10.8 promotes the conversion of XBP1/u to XBP1/s and expands ER diameter, and increases the percentages of apoptotic cells in DF-1 and duckling liver tissues. To investigate the mechanism underlying the MDRV p10.8-induced ER stress and apoptosis, Western blot, siRNA, and co-immunoprecipitation (Co-IP) assays were performed. We found that the MDRV p10.8 protein up-regulates Bip, p-IRE1, XBP1s, and cleaved-caspase 3. Co-IP results reveal that the MDRV p10.8 protein disassociates the Bip/IRE1 complex. Inhibition of IRE1 by 4-methyl umbelliferone 8-carbaldehyde (4u8c) dramatically reversed the MDRV p10.8-modulated increase in levels of XBP1s and cleaved-caspase 3. Knockdown of XBP1 by siRNA reversed the increased level of p10.8-modulated cleaved-caspase 3. The present study provides mechanistic insights into the MDRV p10.8 protein induces ER stress, resulting in apoptosis via the Bip/IRE1/XBP1 pathway in DF-1 cells and duckling livers. [ABSTRACT FROM AUTHOR]

The transgenic alga lba of Chlamydomonas reinhardtii yielded H 2 with 50%–180% higher than the control strain. Further experiments showed that photosynthetic rates and photosynthetic reaction center II's photochemical capacities of the transgenic algae obviously decreased 33.4%–85.9% and 30.0%–51.7%, respectively, compared with those of the control. On the contrary, respiration rates of the transgenic algae significantly increased, with 40.0%–200.0% higher than those of the control. Furthermore, starch contents of the transgenic algae were also improved significantly by 79.1%–592.8% compared with the control. Therefore, the reason of H 2 yield improvement of the transgenic alga lba is not only due to its decrease of photosynthetic capacity and increase of the respiration rate, but also due to the metabolic changes related to starch metabolism, photosynthesis and respiration which is possibly caused by hetero-expression of lba gene in chloroplasts of C. reinhardtii , indicating the potential of utilization of lba gene to improve hydrogen yield of micro-green algae. [ABSTRACT FROM AUTHOR]

Abstract Nostoc flagelliforme is a terrestrial cyanobacterium whose exopolysaccharides have been found to have antioxidant, antivirus, and antitumor properties. Alkaline conditions could effectively increase the polysaccharide yield of N. flagelliforme. In this study, to explore the potential mechanism underlying this effect, the physiological and proteomic changes in N. flagelliforme under alkaline conditions were determined. The polysaccharide accumulations of N. flagelliforme were examined in alkaline and neutral cultures, and proteomic analysis was carried out to identify candidate proteins related to polysaccharide accumulation under alkali stress. Comparison of proteins from cells grown in pH 7.5 and 9.0 media, using two-dimensional electrophoresis (2-DE), enabled the identification of seven proteins related to polysaccharide secretion, which showed significant differences in abundance. The differential expression of those proteins led to metabolic changes, including glycolipid and peptidoglycan accumulation and reduced chlorophyll synthesis. Meanwhile, photosynthesis and Rubisco activity were increased in high-pH conditions, with variable fluorescence/maximal fluorescence (Fv/Fm) and Rubisco activity being 1.24- and 2.50-fold those of the control, respectively. The activities of enzymes related to polysaccharide production ranged from 1.15- to 1.83-fold those of the control, suggesting that the mechanism by which alkaline conditions promote polysaccharide accumulation in N. flagelliforme is to redirect carbon flow into the sugar nucleotide synthesis pathway. Furthermore, the activities of antioxidant enzymes, such as superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD), in N. flagelliforme increased in the pH 9.0 treatment, reaching 3.0-, 3.9- and 2.7-fold of the control, respectively. These results provide a new foundation for study of the mechanism of polysaccharide accumulation and the response of N. flagelliforme to alkaline conditions. Highlights • The polysaccharide production of N. flagelliforme was increased under alkaline conditions. • Seven proteins related to polysaccharide secretion were identified. • Photosynthesis and Rubisco activity increased under high-pH conditions. • The activities of enzymes involved in polysaccharide production were enhanced. • Oxidoreductase activity in N. flagelliforme was increased under alkaline conditions. [ABSTRACT FROM AUTHOR]

Stenoloma chusanum is a traditional Chinese medicine with very high total flavonoid content (TFC) and the total phenolic content (TPC). To explore its phytochemicals and potential in therapeutic applications, the antioxidant activity and tyrosinase inhibitory activity of S. chusanum fractions prepared by extraction with petroleum ether (PF), chloroform (CF), ethyl acetate (EF), n -butanol (NF) and water fractions (WF) as well as their flavonoid profiles were investigated. All these five fractions contained appreciable quantities of flavonoids and phenols, but the EF fraction was richest one with TPC and TFC values of 385.5 mg gallic acid equivalents/g and 746.8 mg rutin equivalents/g, respectively. The EF, NF, and CF fractions showed significant antioxidant activity, presumably due to their high flavonoid and phenol contents. All five fractions also caused dose-dependent inhibition of tyrosinase activity, and the PF fraction was a stronger inhibitor than the positive control inhibitor arbutin. However, the compounds responsible for this activity are currently unknown. These fractions’ chemical profiles were analyzed by LC/MS, revealing that their most abundant secondary metabolites were flavonoids and alkaloids. The EF and NF fractions contained similar compounds, including flavonols, flavones, isoquinolines, filicinic acid, and gigantecine. Further work on S. chusanum to isolate these compounds and explain the mechanisms responsible for their antioxidant activity and anti-tyrosinase activity is warranted. [ABSTRACT FROM AUTHOR]

Stenoloma chusanum is a traditional Chinese medicinal herb with a very high total flavonoid content (TFC). The seasonal dynamics of the TFC and total phenolic content (TPC) in S. chusanum , as well as antioxidant activity, were investigated. The TFC and TPC showed clear seasonal dynamics, reaching their maxima (24.63 ± 1.34% and 9.58 ± 0.41%, respectively) in February. The TFC and TPC in the aerial parts of the plant were much higher than those in the subterranean parts; however, the antioxidant activities of the extracts from the subterranean parts were slightly higher than those from the aerial parts. Moreover, the extracts exhibited higher inhibition against tyrosinase than against arbutin (the positive control). The extract from S. chusanum collected in February was associated with the highest proliferation and apoptosis of K562 cells. The phytochemicals in the extract were analyzed using LC-MS, and were found to comprise of 12 flavonoids, five alkaloids, one sesquiterpenoid and one phenypropanoid. In conclusion, S. chusanum exhibits multiple bioactivities; these results could contribute to the therapeutic application of the plants in indigenous medicine. [ABSTRACT FROM AUTHOR]

Chlamydomonas reinhardtii cc124 and Azotobacter chroococcum bacteria were co-cultured with a series of volume ratios and under a variety of light densities to determine the optimal culture conditions and to investigate the mechanism by which co-cultivation improves H 2 yield. The results demonstrated that the optimal culture conditions for the highest H 2 production of the combined system were a 1:40 vol ratio of bacterial cultures to algal cultures under 200 μE m −2 s −1 . Under these conditions, the maximal H 2 yield was 255 μmol mg −1 Chl, which was approximately 15.9-fold of the control. The reasons for the improvement in H 2 yield included decreased O 2 content, enhanced algal growth, and increased H 2 ase activity and starch content of the combined system. [ABSTRACT FROM AUTHOR]

Three algae strains— Chlamydomonas reinhardtii hemHc-lbac (transgenic), cc124 and cc503—were co-cultured with Bradyrhizobium japonicum to improve H 2 production. The maximum H 2 productions of the three different co-cultures were 3.5-fold, 17-fold and 4.4-fold of the pure algal cultures. Meanwhile, the biomass of each of the algae strains was increased by B . japonicum . Furthermore, the respiratory rates of the co-cultures were 1.4-fold, 1.2-fold and 2.6-fold higher than the controls, respectively; the in vitro maximum hydrogenase activities of the co-cultures were 1.1-fold higher, equal to 2.4-fold higher than those of the controls, respectively, and the in vivo maximum hydrogenase activities of the co-cultures were 1.5-fold, 3.8-fold and 2.1-fold higher than the controls, respectively. The maximum starch content of the co-cultures were 8.3-fold, 8.4-fold and 4.4-fold higher than the content of the controls, respectively. Therefore, B . japonicum improved the H 2 production of the co-cultures by increasing the biomass, respiratory rates, hydrogen activity and starch content of the co-cultures relative to those of pure algae cultures. [ABSTRACT FROM AUTHOR]

[Display omitted] • Identifying the interactions of land use functions (LUFs) is of great significance for ecologically fragile areas. • Construct a comprehensive quantitative evaluation index system of land use functions (LUFs) in Lanzhou-Xining urban agglomeration (LXUA) from the perspective of "production-living-ecological" function. • Identify the trade-offs and synergy of LUFs in LXUA, and explored the spatio-temporal influencing factors of LUFs in LXUA at different scales. Identifying the interactions of land use functions (LUFs) is of great significance for alleviating the contradiction between human and land, and promoting sustainable use of land resources. However, few studies concerned the interactions of LUFs in urban agglomerations of ecologically fragile areas in China at a fine scale. In this study, we constructed a quantitative and visualized evaluation system of LUFs that conforms to three primary functions, ten sub-functions, and nineteen indicators of Lanzhou-Xining urban agglomeration (LXUA) in the upper reaches of the Yellow River basin based on the production-living- ecological functions. Then, the comprehensive evaluation method, hot spot analysis, and geographic weighted regression (GWR) model were used to identify the interactions among LUFs and influencing factors of LXUA from 2000 to 2020 at the county and grid scales. The results show that the LXUA is dominated by ecological function (EF), and EF and living function (LF) showing a "U" shaped change feature, while production function (PF) show an inverted "U" shaped change feature. Meanwhile, the cold spots and hot spots of PF and EF present the spatial characteristic of "overall dispersion and local aggregation", while the LF has no cold spots, and the hot spots present the spatial characteristic of "point-axis". Moreover, the PF and LF are in a synergistic relationship at two scales, with complementarity in space, while the EF and PF and the PF and LF are both in a trade-offs relationship, with overlap in space. Finally, socioeconomic development factors have remarkable impact on LUFs at the county scale, while LUFs at the grid scale is the comprehensive result of natural conditions, socioeconomic factors, accessibility and political factors. The results can provide references for the LXUA to differentiated design the land use policy, and provide empirical case for other ecologically fragile areas to alleviate the trade-offs of LUFs. [ABSTRACT FROM AUTHOR]

To investigate the effects of Hericium erinaceus polysaccharide (HEP) on immunity in Muscovy duck reovirus (MDRV)-infected ducklings and explore its mechanism of action, an MDRV contact-infection model was established. Then, we investigated the influence of HEP on morphology of main immune organs in MDRV-infected ducklings by HE staining, while antioxidant capacity (T-AOC, MDA), serum protein levels (TP, ALB, GLO), complement levels (C 3 , C 4) and antibody levels (IgA, IgM, IgG) were detected. Apoptotic indexes (apoptosisi rate and FAS-L) were also quantified by TUNEL method and immunohistochemical staining. Meanwhile, FADD and CytC (apoptosis-related genes), were tested by quantitative RT-PCR. Results showed that HEP could reduce the injuries of immune organs caused by MDRV. Additionally, HEP markedly diminished MDA (p < 0.01), while significantly increased T-AOC, TP, ALB, GLO, C 3 , C 4 , IgA, IgM and IgG (p < 0.01 or p < 0.05). Then, HEP shifted apoptosis time to an early MDRV-infected stage and reduced apoptosis at later MDRV-infected stage. This was associated with changes of FADD and CytC. Collectively, our data suggested that HEP could reduce the immunesuppression by many ways, such as decreasing organs' injuries, improving antioxidant capacity, serum proteins levels, antibody levels and complement levels, while diminish the apoptosis by lowering the FADD and CytC. Unlabelled Image • Hericium erinaceus polysaccharide (HEP) can regulate immunity of Muscovy duckling. • HEP induced apoptosis in early infected-stage, then reduced apoptosis. • HEP promoted apoptosis by activating Cytochrome c. • HEP inhibited apoptosis by inhibiting Fas-associated death domain and Cytochrome c. [ABSTRACT FROM AUTHOR]

Hericium erinaceus polysaccharide (HEP) is a bioactive substance present in the fruiting bodies of H. erinaceus. Previously we have shown that HEP can repair the intestinal injury caused by Muscovy duck reovirus (MDRV) infection in Muscovy ducklings. To examine the effect of HEP on intestine mucosal MDRV immunity and explore its possible mechanisms, an MDRV contact-infection model in the Muscovy ducklings was established. Transcriptome sequencing analysis was then performed to investigate the mechanism of action of HEP on intestine mucosal MDRV immunity. During the infection, the expression levels of genes involved in cellular activities (protein translation and binding, cytokine interaction, and adhesion molecules activities) in the infected ducklings were increased. The expression levels of adhesion molecules (α4β7, LFA-1) and chemotaxis cytokine receptors (CCR7, CCR9, and CCR10) were also significantly upregulated. Following HEP treatment, cellular activities and cytokines upregulated to various degrees play crucial roles in the immune defenses and antiviral activities of Muscovy ducklings. ELISA analysis results were consistent with the results of the transcriptome analysis. Overall, our results provide a basis for further studying the underlying mechanisms of HEP in regulating mucosal immunity and for the clinical application of HEP in controlling MDRV infection in the Muscovy duck industry. • Sequence information in the Muscovy duck remains scant, and this study enriches the available data in the Muscovy duck. • HEP regulates the lymphocyte homing in Muscovy ducklings in response to MDRV infection. • Our results provide a basis for the clinical application of HEP in controlling MDRV infection in the Muscovy duck industry. [ABSTRACT FROM AUTHOR]

A comparative study was performed to investigate the differences in plasma pharmacokinetics (PKs) and tissue residues of trimethoprim (TMP) between silky fowls and 817 broilers. The 2 breeds of chickens received compound sulfadiazine suspension by gavage at 20 mg/kg (measured as TMP). Blood and tissue samples were collected at predetermined time points. The concentrations of TMP in plasma and tissue samples were determined by a validated high-performance liquid chromatography (HPLC) method. The plasma concentration-time data were subjected to noncompartment analysis by WinNonlin program (Pharsight Co., Mountain View, CA). The mean plasma concentrations of TMP in silky fowls were significantly lower than those in 817 broilers at all time-points. Significant differences were also observed between silky fowls and 817 broilers in maximum concentration (C max), area under the curve from time 0 to 24 h (AUC 0 → 24 h), apparent volume of distribution (V d), and total body clearance (Cl B). Silky fowls had significantly higher muscle TMP concentrations and longer tissue residual time than 817 broilers. The tissue concentration of TMP followed the order of leg muscle > breast muscle > liver, which was obviously different from that of 817 broilers. The half-lives of TMP in the leg muscle, breast muscle, and liver of silky fowls were 31.42, 10.78, and 0.38 d, respectively. The current withdrawal time (WDT) was not sufficient to prevent violative residues of TMP in the edible tissues of silky fowls, and a WDT much longer than 8 d might be required. [ABSTRACT FROM AUTHOR]

• The histopathological effects of Muscovy duck reovirus was examined in vivo. • The virus degrades the morphology and function of the small intestinal mucosa. • The virus alters the local density of immune-related cells. • The virus also alters the secretion of immune-related factors. Muscovy duck reovirus (MDRV) causes serious immunodeficiency in the intestinal mucosa, although the underlying histopathological mechanisms remain unclear. Thus, we investigated the impact of MDRV infection on intestinal morphology using hematoxylin and eosin staining. Immune-related cells were also quantified by staining with hematoxylin and eosin, toluidine blue, and periodic acid-Schiff stain, or by immunohistochemistry and cytochemistry for lectin. Similarly, CD4+ and CD8+ cells were quantified by flow cytometry, and the expression of several immune-related molecules was quantified by radioimmunoassay. We found that MDRV clearly damaged the intestinal mucosa, based on tissue morphology, villus length, villus width, intestinal thickness, villus height/crypt depth ratio, and villus surface area. MDRV also altered the density or distribution of lymphocytes, mastocytes, and goblet cells in the small intestinal mucosa, as well as microfold cells in Peyer's patches. In addition, MDRV markedly depleted CD4+ cells from the intestinal mucosa and lowered the CD4+:CD8+ ratio in peripheral blood. Moreover, MDRV diminished the levels of secretory IgA and mucosal addressin cell adhesion molecule-1 (p < 0.01), but elevated those of histamine and nitric oxide (p < 0.01 or p < 0.05). Finally, MDRV significantly suppressed IL-1β, IL-4, IL-5, and IL-8 levels (p < 0.01 or p < 0.05) mid-infection. Collectively, our data suggest that MDRV severely damages the structure and function of the intestinal mucosa by modulating immune cells and immune-related factors, thus leading to local immunodeficiency. Our findings lay the foundation for further research on the pathogenesis of MDRV. [ABSTRACT FROM AUTHOR]

Identifying early signs of anthropogenic disturbances in protected areas is critical for determining overuse, safeguarding natural beauty, protecting biodiversity, and sustaining resource use and economy. Assessing disturbances to aquatic systems of such areas is challenging due to the low-dose, diffused, and cumulative nature of disturbances; high risk at iconic sites; and difficulty of linking human activities with degradation. Using Jiuzhaigou Nature Reserve as an example study to overcome such challenges, we developed an approach that integrated human activities known to impact aquatic systems to calculate a holistic disturbance index for assessing the extent of human uses at scales of entire reserve and individual sub-watersheds. We linked human disturbance index with benthic algae and macroinvertebrate indicators of individual waterbodies to identify early signs of degradation. We conducted in situ nutrient experiments and intensive sampling of biota at iconic sites with early signs of degradation to provide direct linkage between tourist activities and eutrophication, and to pinpoint mechanisms of how human disturbances have resulted in such degradations. We found that the human disturbance index significantly correlated with benthic algae and macroinvertebrate indicators, and Jiuzhaigou is largely in healthy condition. For the two identified iconic sites with early signs of degradation, intensive tourist activities at observation and rest areas of Five-Color Lake seemed to link to extra amount of nitrogen input into the lake and resulted in overgrowth of phytoplankton and filamentous algae during summer peak tourist months. Extra amount of phosphorus input from tourism activities at Pearl Shoal seemed the cause of changes in substrate colors and of shifts in attached moss and algal communities. Our example study demonstrates that early signs of degradation can be visually observed and should be further assessed by measuring water quality and sensitive biological indicators at high risk areas of a waterbody during summer and peak tourist seasons. Sensitive biological indicators (e.g., intolerant diatom and macroinvertebrates) are better indicators than nutrient concentrations because of rapid assimilation of nutrients by algae and macrophytes. Our assessment approach and findings of studying Jiuzhaigou have broad applications to other protected areas for determining overuse, and hence for making science-based policy and taking adequate management actions to prevent overuses. [ABSTRACT FROM AUTHOR]

To elucidate the effect of Hericium erinaceus polysaccharide (HEP) on the intestinal mucosal immunity in normal and Muscovy duck reovirus (MDRV)-infected Muscovy ducklings, 1-day-old healthy Muscovy ducklings were pretreated with 0.2 g/L HEP and/or following by MDRV infection in this study, duodenal samples were respectively collected at 1, 3, 6, 10, 15 and 21 day post-infection, tissue sections were prepared for observation of morphological structure and determination of intestinal parameters (villus height/crypt depth ratio, villus surface area) as well as counts of intraepithelial lymphocytes (IELs), goblet cells, mast cells. Additionally, dynamics of secretory immunoglobin A (sIgA), interferon-γ (IFN-γ) and interleukin-4 (IL-4) productions in intestinal mucosa were measured with radioimmunoassay. Results showed that HEP significantly improved intestinal morphological structure and related indexes, and significantly inhibited the reduction of intestinal mucosal IELs, goblet cells and mast cells caused by MDRV infection. Furthermore, HEP significantly increased the secretion of sIgA, IFN-γ and IL-4 to enhance intestinal mucosal immune functions. Our findings indicate that HEP treatment can effectively repair MDRV-caused injures of small intestinal mucosal immune barrier, and improve mucosal immune function in sick Muscovy ducklings, which will provide valuable help for further application of HEP in prevention and treatment of MDRV infection. [ABSTRACT FROM AUTHOR]

Zooplankton play an important role in the pelagic food web as a mediator of nutrient and energy fluxes. Understanding factors determining zooplankton abundance, composition, and dispersal provides information needed for improving plankton dynamic predictions and enhancing effective water resource management and biodiversity conservation. We studied zooplankton dispersal and identified factors influence zooplankton composition and abundance under a unique in situ environment with four connected water types from the natural river to a man-made main canal, then interior canal-web, and finally lake that have different flow regimes. We found that, after seven years creation of the water system and zooplankton community development, the main canal, interior canal-web, and lake had 53%–64% zooplankton taxa similar to their water origin river but that each water type was represented and dominated by different zooplankton taxa. Our optimal model identified three key local factors that affected the difference in zooplankton abundance and composition among the four water types: Chlorophyll a concentration, turbidity, and salinity. We concluded that both zooplankton dispersal through watercourse and species sorting by local factors were important for structuring communities in our study system. Since most studies on dispersal and influence of local factors on zooplankton assemblages in new environment have been done largely in temporal ponds, our findings provide unique insights on how zooplankton communities are jointly regulated by their species dispersal origins and local environmental factors in newly created canals and lakes. [ABSTRACT FROM AUTHOR]

Twenty compounds were isolated from the fern of Pyrrosia davidii (Baker) Ching. These compounds included three steroids (1 , 2 , and 3), one pigment (4), eleven flavonoids (5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , and 15), two terpenoids (16 , 17), one phenolic acid (18), and two fatty acids (19 , 20). The structures of the compounds were determined by comparison of measured NMR spectroscopic data with previously reported data. Except for Compound 1 and 11 , all the compounds were isolated for the first time from Pyrrosia davidii (Baker) Ching, and Compounds 6 , 9 , 17 , 19 , and 20 were isolated for the first time from the genus Pyrrosia Mirbel. The chemotaxonomic significance of these compounds was discussed. • Eighteen compounds were isolated from the fern of Pyrrosia davidii for the first time. • Compounds 6 , 9 , 17 , 19 , and 20 were isolated from the genus Pyrrosia Mirbel for the first time. • The chemotaxonomic significance of these isolates was discussed. [ABSTRACT FROM AUTHOR]

Avian Leukosis Viruses (ALVs) are associated with neoplasias, immune suppression and reduced performance in chicken flocks. In the present study, a naturally occurring recombinant strain of ALV (FJ15HT0) was isolated from an infected flock of Chinese “Hetian” chickens, and was subsequently identified as an exogenous ALV by immuno-fluorescence assay (IFA), PCR and following entire proviral DNA nucleotide sequencing. This isolate is revealed as a novel recombinant virus, lacking viral oncogenes, with the gp85 (93.4%) of subgroup B, the U3 (92.1%) and R (95.2%) region of subgroup J, the U5 (93.8%) region and 5′UTR (95.7%) of subgroup C, as well as the gp37 (90.6%) and 3′ (92.2%) of ALV-E. The simulative congenital infection with this isolate in SPF chickens resulted in significant weight loss ( P < 0.05) and a significant reduction in the humoral immune response to the live NDV vaccine ( P < 0.05), but not to the inactive AIV-H 5 vaccine ( P > 0.05). Foci of lymphocytomas were observed in tissues of congenitally infected chickens at 11 weeks post-hatch, demonstrating the acute oncogenicity of the isolate. [ABSTRACT FROM AUTHOR]

Flavonoid extracts of fern are conductive to phylogeny and genesiology as well as pharmacological activities. Ferns are widely distributed in Tianmu Mountain. Flavonoid concentrations and antioxidant activity in extracts of 49 ferns from Tianmu Mountain were investigated and analyzed. The result showed that the total flavonoid contents of 49 ferns ranged from 3.3 to 191.7 mg/g (w/w). Total flavonoid contents and antioxidant activity of fern allies were lower than those of filicinae. Woodwardia japonica a contained the highest flavonoid content (191.7 mg/g). The results also showed that most of ferns from Tianmu Mountain had strong antioxidant activity. The extracts from A. rhomboidea showed the highest DPPH scavenging activity, while extracts from W. japonica a showed the highest ABTS scavenging activity. The flavonoid contents of ferns are affected by ecological factors. In general, ferns living under dimmer sunshine have higher flavonoid contents and stronger ABTS scavenging activity than those living under strong sunshine. The ferns grown in trees, high altitude and high latitude contain higher flavonoid concentrations, whereas the ferns grown in soil, high altitude contain higher antioxidant activity. [ABSTRACT FROM AUTHOR]

Park managers in nature reserves need scientifically defensible and operationally feasible ecological indicators to better manage protected areas for both nature conservation and tourism. Such needs are much more urgent in karst aquatic ecosystems where spectacular natural scenic wonders attract millions of visitors to natural areas with streams and lakes that are particularly vulnerable to nutrient pollution. To identify a set of biotic indicators of phosphorus (P) pollution in a karst stream, we conducted an in situ P enrichment experiment in a nearly pristine karst stream located at a UNESCO world heritage site in China. Our results show that both benthic algal assemblages and macroinvertebrates were sensitive to P enrichment. Changes in diatoms (e.g., Achnanthidium minutissimum, Delicata delicatula ) and macroinvertebrates (e.g., collectors) were indicative of P enrichment. The color change of travertine bryophyte beds from creamy white to green was largely due to increase in filamentous green algae such as Zygnema sp., which may provide a visual cue for P enrichment and pollution. Our findings, in conjunction with further studies that directly link these indicators with human disturbance (e.g., tourist activities) throughout the park, could improve the operation of park managers in minimizing tourist-induced nutrient pollution and in operationalizing these indicators in the current environmental monitoring and assessment program. [ABSTRACT FROM AUTHOR]

Zooplankton in river systems have seldom been studied in the context of metacommunity ecology. Spatial factors (e.g., river connectivity, directionality, and man-made dams) may play a key role in influencing the metacommunity structure of rotifers because of their small body size and weak mobility. In contrast, local environmental factors (e.g., physicochemical habitat) may be more important to crustaceans due to their larger body size and stronger mobility. We sampled zooplankton and environmental factors during wet and dry seasons from 47 sites along the Ying River in China to assess the roles of the spatial and environmental factors in structuring zooplankton metacommunities. We used Moran’s eigenvector map and asymmetric eigenvector map to model the influences of river connectivity, directionality, and man-made dams on zooplankton metacommunity structure. We then used partial redundancy analysis to identify individual and interactive effects of spatial and environmental factors on both the entire zooplankton assemblages and two zooplankton groups of different body sizes and mobility. A total of 101 taxa were identified and taxa richness was higher in the wet season (72) than in the dry season (58). Zooplankton assemblages were primarily dominated by rotifers. For the dry season, environmental factors such as total nitrogen, water temperature, and pH explained a significant portion of variation in zooplankton community; river connectivity was more important than river directionality to zooplankton metacommunity structure. For the wet season, spatial factors were more influential than environmental factors such as dissolved oxygen and water transparency; river directionality played an important role in influencing the spatial structures of both environmental condition and zooplankton metacommunity. We also found significant effects of man-made dams on zooplankton metacommunity structure. Spatial factors are more influential in structuring small body size and weak mobility rotifer communities, while environmental factors are more important in determining the variation of crustaceans due to their larger body size and stronger mobility. We concluded that river connectivity and directionality should be considered as key factors for better understanding the spatial processes of planktonic passive dispersers in river networks. Our study provides new insight on understanding riverine zooplankton metacommunity ecology and contributes to the knowledge of river ecosystem health monitoring and management. [ABSTRACT FROM AUTHOR]

The pro- and inflammatory cytokines fail to effectively inhibit FAdV-4, which has always puzzled us. In the current study, the data determined that the mRNA levels of interferons were significantly enhanced in the livers and LMH cells from 24 h to 72 h post FAdV-4 infection. But the viral load of FAdV-4 was still significantly increased, which meant that FAdV-4 evaded innate immune response. We additionally revealed that the protein levels not mRNA levels of PKR were degraded in host cell at 48 h post FAdV-4 infection. Moreover, the results of over expression and silent expression of PKR revealed that PKR could inhibit FAdV-4 proliferation. These results indicated that FAdV-4 degraded the protein levels of PKR to evade innate immune response. We also found that the protein degradation levels of PKR induced by FAdV-4 were recovery in LHM cells after treatment with proteasome inhibitor MG132, and ubiquitin-specific proteases inhibitor DUB-IN-1. Furthermore, our current data presented that FAdV-4 52/55 K protein directly interacted with PKR and degraded it determined by Co-immunoprecipitation and immunofluorescence. We also determined that 52/55 K protein triggered PKR degradation, and the degradation of PKR could be recovery in LHM cells after treatment with MG132, or DUB-IN-1, respectively. Finally, our data demonstrated that 52/55 K protein was a ubiquitylase that could directly degrade PKR protein in host cells via the ubiquitin-proteasome pathway. Therefore, the current study firstly revealed that FAdV-4 52/55 K protein played the key role in triggering PKR degradation by ubiquitin-proteasome system pathway to escape from innate immunity response. • FAdV-4 degrades PKR protein to evade effective innate immunity. • We elucidated 52/55 K protein of FAdV-4 triggers the degradation of PKR protein in host cells. • The ubiquitin–proteasome system mediates the degradation of PKR protein-induced by 52/55 K protein was further explored. [ABSTRACT FROM AUTHOR]

[Display omitted] • Temperature threshold affect the final factors included in the predictive model. • The increase of trace elements could be the key factor causing cyanobacterial blooms. • Accurate long-term prediction can be achieved with less field data by using our model. Harmful cyanobacterial blooms damage aquatic ecosystems and pose a threat to human health. To identify key factors causing cyanobacterial blooms in eutrophic shallow lakes, we analyzed cyanobacterial and physicochemical water samples of 12 sites collected monthly from December 2012 to December 2019 in Dianshan Lake. We found that the rapid growth of cyanobacteria was limited by a temperature threshold. When the air temperature was below 18 °C, the sampled physicochemical factors could not make difference in cyanobacterial abundance regardless the values of these parameters. However, when the air temperature was above 18 °C, the measured physicochemical factors played important roles in influencing cyanobacterial abundance. We developed a data-driven predictive model for cyanobacterial blooms based on seven-year data from Dianshan Lake using multiple logistic regression. Such a model could be easily used to predict cyanobacterial blooms. Our weight analysis of model parameters indicated that dissolved substances other than TN and TP are the key factor determining cyanobacterial blooms in nitrogen and phosphorus rich shallow freshwater lakes once air temperature is above 18 °C. Eutrophic shallow lakes are prone to cyanobacterial blooms, and unwashed data analysis may mask key factors determining cyanobacterial blooms, which obscures the prediction of cyanobacteria blooms. Our results are helpful to uncover the real causes of the blooms of eutrophic shallow lakes in China and elsewhere, and hence improve the understanding and management in controlling cyanobacterial blooms. [ABSTRACT FROM AUTHOR]

With increasing human population and urbanization, tourism in natural reserves and other protected lands is growing. It is critical to monitor and assess the impacts of tourism on ecosystem health. However, there is a general lack of information on biological communities in natural reserves of developing countries and of tools for assessing human impacts. In the present study, we investigated macroinvertebrate assemblages in nine lakes in Jiuzhaigou Natural Reserve of China. Both benthic (20 dips of D-net) and light-trap samples (2 h) were collected at each lake and all benthic specimens and adults of Ephemeroptera, Plecoptera, and Trichoptera (EPT) were identified and counted. Water temperature and water quality variables were measured on site or in the Lab. Seventy taxa were recorded and dominated by dipterans and caddisflies. Light traps contributed 47% of taxa richness and 66% of EPT richness at the lakes. Detrended Correspondence Analysis showed that water temperature and tourism index were strongly associated with the changes of assemblage composition. Taxa richness and EPT richness calculated for the composite samples (benthic + light trap) were well fit with Poisson generalized linear model (adjusted R 2 = 0.83 and 0.85, respectively), generally decreasing with increasing elevation, tourism index, and total-N. Tourism index was ranked as the top predictor for EPT richness based on multiple model weights, and elevation for taxa richness. In comparison, when based on benthic samples, neither of the metrics could be fitted with the seven environmental variables selected. These findings highlight the benefit of combined use of the sampling methods for lake monitoring and offered an analytical guide to developing biological indicators of lake ecosystem health in protected areas. [ABSTRACT FROM AUTHOR]

Fern species have been classified as traditional Chinese medicinal herbs. However, the phytochemicals and bioactivities of most fern species were rarely explored. Herein, we examined the total flavonoid contents, in vitro antioxidant potential and acetylcholinesterase inhibitory activity of the extracts from 15 fern species in Yunnan Province of China. The total flavonoid contents ranged from 4.67 to 125.88 mg/g (w/w, dry weight). Their antioxidant potentials were evaluated by the radical scavenging, superoxide anion scavenging, and reducing power, which indicated that most of the extracts from these fern species showed very strong radical and superoxide anion scavenging ability. However, among these 15 fern species, only five extracts from Pyrrosia petiolosa , Polypodiodes amoena , Araiostegia imbricate , Pseudodrynaria coronans , and Pilea nummulariifolia showed acetylcholinesterase inhibitory activity. The polyphenol profiles of Lemmaphyllum carnosum with highest total flavonoid content were identified as dehydroagastol, bufotalin, chlorogrnic acid, monogalloyl-glucose, luteolin 7- O -β- d -gluscoside, kaempferol 3- O -α- l -rhamnopyr-anoside, myricetin 3- O -rhamnoside, quercetin 3- O -galactoside, apigenin 7- O -glucoside, and Woorenoside II. [ABSTRACT FROM AUTHOR]

The seasonal dynamics of the total flavonoid contents in various parts of Dryopteris erythrosora , a traditional Chinese medicinal fern, and their antioxidant activity were investigated. The total flavonoids content in various parts of D. erythrosora showed an obvious seasonal dynamic change. The total flavonoid contents in stems (from 4.3% to 12.5%) were much higher than that in leaves with an average content of 2.01%. In spring, the total flavonoid contents in stems were relatively low, but increased rapidly from summer to winter. However, the seasonal dynamics of total flavonoid contents in leaves showed different model. The total flavonoid contents in the stems showed a negative correlation with that in the leaves from January to July. The correlation coefficient of about −0.7 was obtained. The antioxidant activity of the extracts also altered in proportion to the change of total flavonoid contents. In general, the extracts from stems always showed highest antioxidant potentials and it was suggested that the stems can be used as crude medicine. [ABSTRACT FROM AUTHOR]

• Cyanobacteria impacted plankton bio-diversity and resource use efficiency. • No clear relation between cyanobacteria and phytoplankton absolute abundances. • Cyanobacteria had opposite relation with phytoplankton and zooplankton bio-diversities. • Cyanobacteria increased total algae and cladocerans RUEs. • Cyanobacteria decreased phytoplankton and rotifers RUEs. Cyanobacterial blooms are global threats to freshwater ecosystem functioning, human health, and ecoservices. We assessed impacts of cyanobacterial bloom intensity on plankton ecosystem functioning using eukaryotic phytoplankton and zooplankton indicators and associated key physicochemical data collected from four seasons of two years at 24 evenly distributed sites in Lake Taihu that has year-around cyanobacterial blooms. Our analyses involved comparison of four site-groups with different bloom intensities and analyzing all sampling sites together using comparison, hierarchical partitioning analysis, generalized additive mixed model, and structural equation model. We found that cyanobacterial abundance positively associated with TP and temperature (negatively with TN:TP), while phytoplankton positively associated with TN. There was an inverse relation trend between relative abundances of phytoplankton and cyanobacteria, but there was no clear trend between absolute abundances of phytoplankton and cyanobacteria. Rotifers were most dominant when cyanobacteria were unabundant, while cladocerans presented higher abundance when cyanobacteria were in high abundance. Phytoplankton functional richness and species richness negatively and zooplankton functional richness and species richness positively associated with cyanobacterial bloom intensity. Cyanobacterial bloom intensity negatively associated with resource use efficiencies (RUEs) of phytoplankton and rotifers, and positively associated with RUE of cladocerans. Our analytical approach of integrating comparison of site-groups and analyzing all sites together uncovered how cyanobacterial bloom intensity shifted and altered physicochemical and biological conditions and plankton ecosystem functioning, and identified the mechanism and strength of the interactive linkages among physicochemical and biological indicators. Although our results may be different from oligotrophic lakes or reservoirs, our findings provide new insights in understanding the impacts of cyanobacterial bloom intensity on the dynamics of plankton communities and ecosystem functioning for polymictic eutrophic lakes, which may have broad application in enhancing the knowledge of this subject and provides the science base for managing polymictic eutrophic lake water quality and ecosystem functioning. [ABSTRACT FROM AUTHOR]

Highlights: [•] Flavonoids contents and bioactivities of extracts from 19 species of ferns were investigated. [•] Antioxidant activities of flavonoids extracts from these ferns showed a weak relationship with its total flavonoid contents. [•] The extract from D. cylindrica and S. chusanum significantly inhibited AChE activity. [•] S. frondosa with very low total flavonoids content showed highest inhibition against A549 cells. [ABSTRACT FROM AUTHOR]

Highlights: [•] Characterization of flavonoids-rich extract from Davallia cylindrica. [•] Flavonoids-rich extract from D. Cylindrica showed similar antioxidant activities with rutin. [•] Flavonoids-rich extract from D. Cylindrica showed cytotoxic effects on A549 cells. [ABSTRACT FROM AUTHOR]

• F1 protein of FAdV-4 could nucleus localization in LMH cells, and the P 26 in NLS was required for F1 protein nucleus entry. • We elucidated the time rule of F1 protein subcellular localization in nucleus of LMH cells. • The importin alpha 1 is required for F1 protein nucleus entry. • F1 protein subcellular localization in nucleus was conducive to the proliferation of FAdV-4. Fiber-1 protein (F1) is the structural protein of Fowl Adenovirus serotype 4 (FAdV-4), which could recondite the receptors of host cytomembrane. In this study, we firstly determined that F1 protein located in nucleus of LMH cells after infection with FAdV-4. We additionally revealed that F1 protein had a classic NLS, and the NLS was required for F1 nucleus entry, which was intently associated to the 26th Pro in NLS. The time rule result indicated that some F1 proteins firstly positioned in the nucleus 6 h posttranfection, and it entirely located in the nucleus 12 h posttranfection, then it ordinarily placed in cytoplasm 18 h posttranfection by means of microscopic fluorescence observation and Western Blotting. Then after transfection with pCI-neo-flag-F1 or infection with FAdV-4, the importin alpha 1 was once investigated whether or not it was required for F1 protein nucleus entry through immunofluorescence and/or Co-IP, results demonstrated that the F1 protein and importin alpha 1 co-located in the nucleus 6 h and 12 h posttranfection. The tiers of F1 protein vicinity in nucleus have been additionally investigated after knockdown expression or overexpression of importin alpha 1, and the results further revealed that importin alpha 1 used to be required for F1 protein nucleus entry. Finally, the function of F1 protein nucleus entry was investigated by qPCR, RT-PCR and Western Blotting, and the results revealed that F1 protein nucleus location was conducive to the proliferation of FAdV-4. In summary, we firstly reveal that the F1 protein of FAdV-4 locates in nucleus infected with FAdV-4, and confirm that importin alpha 1 binds to the NLS of F1 protein to nucleus localization, which promotes the proliferation of FAdV-4. [ABSTRACT FROM AUTHOR]

Abstract: Three bacteria, named L2, L3 and L4, were isolated from contaminated cultures of Chlamydomonas reinhardtii strain cc849 in laboratory. The phylogenetic analysis based on 16S rDNA sequences showed that L2, L3 and L4 belonged to genus Stenotrophomonas, Microbacterium and Pseudomonas, respectively. The co-cultivation of isolated L2, L3 and L4 with purified algae, respectively, demonstrated that moderate bacterial concentration did not affect algal growth significantly but improved algal H2 production obviously. The maximal H2 yields were gained by the co-culture of algae with L2 or L4, about 4.0 times higher than that of the single algal culture. Increased respiration rate or O2 consumption was the main reason for the enhancement of H2 yield of the co-cultures. [Copyright &y& Elsevier]

Highlights: [•] A simple approach to produce H2 from Taihu Lake Microcystis spp. blooms is described. [•] Efficient H2 production occurred in the dark and was inactivated by light. [•] Efficient H2 production resulted from reduced O2 content and enhanced H2ase activity. [•] A post-treatment strategy is proposed to turn algal bloom waste into useful products. [ABSTRACT FROM AUTHOR]

Abstract: The profiles and bioactivities of flavonoids extracted from Dryoathyrium boryanum (Willd.) Ching were investigated. The total flavonoids content in extract from D. boryanum is about 145.8mg/g. By means of HPLC–DAD–ESI–MS, the main flavonoids in D. boryanum were tentatively identified as 3-hydroxyphloretin 6′-O-hexoside, quercetin-7-hexoside, apigenin7-O-glucoside, luteolin 7-O-glucoside, apigenin 7-O-galactoside, acacetin 7-O-(α-D-apio-furanosyl) (1→6)-β-d-glucoside, 3-hydroxy phloretin 6-O-hexoside, luteolin-6-C-glucoside. 0.21mg/ml flavonoids extract from D. boryanum showed very strong superoxide anion radical scavenging potential, which is higher than that of rutin (0.25mg/ml). The extract (0.21mg/ml of flavonoids) from D. boryanum exhibited similar DPPH scavenging potential with that of rutin (0.25mg/ml). However, rutin (0.25mg/ml) showed a significantly higher reducing power and ABTS scavenging potential than that of 0.21mg/ml flavonoids extract from D. boryanum. It had no effect on acetylcholinesterase. D. boryanum can be considered as a medicinal plant and the flavonoids from D. boryanum are excellent antioxidants. [Copyright &y& Elsevier]

Abstract: The profiles and bioactivities of flavonoids extracted from Dryopteris erythrosora were investigated. The total flavonoid content in full plant of D. Erythrosora is about 14.33%. The main flavonoids in D. Erythrosora were identified as gliricidin 7-O-hexoside, apigenin7-O-glucoside, quercetin 7-O-rutinoside, quercetin 7-O-galactoside, keampferol 7-O-gentiobioside, keampferol-3-O-rutinoside, myricetin 3-O-rhamnoside and quercitrin by means of HPLC-DAD–ESI-MS. Flavonoids (0.36mg/ml) extract from D. erythrosora showed similar 2,2-diphenyl-1-picrylhydrazyl free radical (DPPH ), 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) radical (ABTS ), superoxide anion scavenging potential and ferric reducing antioxidant potential (FRAP) with that of rutin (0.80mg/ml). However, the antioxidant power by FRAP assay of 0.36mg/ml flavonoids extract from D. erythrosora was much weaker than that of 0.80mg/ml rutin. Moreover, the flavonoids extract from D. erythrosora showed obvious cytotoxic effects on A549 cells. The antioxidant activities of flavonoids extracts from 69 ferns showed a significant reciprocal proportion to the total flavonoids contents. The flavonoids extract from D. erythrosora exhibited a dose-dependent inhibition against acetylcholinesterase. Moreover, the anticancer activity slightly increased with improving antioxidant potential of fern flavonoids. Fern flavonoids are excellent function foods. [Copyright &y& Elsevier]

Abstract: Co-cultivation of Bradyrhizobium japonicum with Chlamydomonas reinhardtii strain cc849 or the transgenic strain lba, which was hetero-expressed the gene of the soybean leghemoglobin apoprotein Lba in chloroplasts of the strain cc849, in Tris–acetate-phosphate (TAP) or TAP-sulfur free media, improved H2 yield. H2 production was 14 times and growth was 26% higher when strain lba and B. japonicum were co-cultured, as compared with cultivation of the algal strain alone under the same conditions. The increase in respiration rate or fast O2 consumption by about 8 times in the co-cultures was the major reason for the improvement. [Copyright &y& Elsevier]

Abstract: To identify genes important for the photoproduction of H2 of Chlamydomonas reinhardtii, random insertional mutants, by the ble gene encoding the enzyme with zeomycin resistant properties, were screened for clones with changed H2 production. One of the mutants, denoted T1, with 7.8-fold of H2 yield and about 23% of respiration rate increased compared with the parental strain cc849 was obtained among the zeomycin-resistant transformants. The photosynthetic rate and Fv/Fm, the efficiency of PSII primary photochemistry of T1 declined. Therefore, the photosynthesis/respiration capacity ratio (P/R ratio) of T1 was reduced compared with strain cc849. However, the growth of the mutant T1 was not inhibited, indicating that T1 was a good mutant for further studies of the genes improving H2 yield by lowering the photosynthetic capacity and/or enhancing the respiration capacity in C. reinhardtii, and had potential to be used in further improvement of H2 generation by further biotechnological approaches. [Copyright &y& Elsevier]

Abstract: Treatment with NaHSO3 induces a 10-fold increase in H2 photoproduction in the filamentous N2-fixing cyanobacterium Anabaena sp. strain PCC 7120. However, it is unclear whether this treatment also increases H2 photoproduction in green alga. In this study, treatment with 13mM NaHSO3 resulted in about a 200-fold increase in H2 production in Chlamydomonas reinhardtii, and this increase was most probably the result of reduced O2 content and enhanced hydrogenase activity. Compared to the conventional strategy of sulfur deprivation, NaHSO3 treatment results in a higher maximum rate of H2 photoproduction, greater efficiency of conversion of light energy into H2, shorter half-time to produce the maximum accumulated H2 levels, and reduced costs because no centrifugation is involved. We therefore conclude that NaHSO3 treatment is an efficient, rapid, and economic strategy for improving photobiological H2 production in the green alga C. reinhardtii. [Copyright &y& Elsevier]

Abstract: According to the codon bias in the chloroplast genome of Chlamydomonas reinhardtii, the codon-optimized coding regions of both the ferrochelatase gene, hemH, from Bradyrhizobium japonicum and the leghemoglobin gene, lba, from Glycine max were synthesized de novo and transferred into the chloroplast of C. reinhardtii. The expression level of hemH-lba protein was improved by 6.8 folds in the codon-optimized transgenic alga compared with the non-optimized one under both normal and anaerobic conditions. H2 yield was 22% and the respiration rate was 44% higher in the codon-optimized transgenic algal cultures than those of the non-optimized ones, and was 450% and 134% higher than those of the control cultures, respectively. The transcript levels of hydA1 and hydA2 in the hemH-lba transgenic alga were also more stable and higher than those of the control alga. These results demonstrate that codon optimization increased the expression level of hemH-lba protein in the chloroplast of C. reinhardtii and improved algal H2 yield by enhancing the respiration rate resulting in low O2 content in the medium and up regulation of the expression of hydA1 and hydA2 in cells, thereby confirming the potential of the utilization of leghemoglobins for H2 production in green algae. [ABSTRACT FROM AUTHOR]

Abstract: An ORF cDNA fragment of one of leghemoglobin genes, lba was cloned from Glycine max and transferred into chloroplasts of Chlamydomonas reinhardtii. More rapidly O2 consumption, lower O2 content and higher H2 output were monitored in the transgenic algal cultures than those in WT cultures either in S-free or S-containing medium. Maximum expression of lba in the transgenic algae consisted with the time when minimal O2 contents and maximal H2 evolution occurred. The highest H2 production achieved in sulfur-free medium for both algal cultures. When restoring sulfate in the medium, H2 production in the transgenic algal cultures kept steadily around 130–145μl per bottle while that in WT cultures decreased gradually from 98μl per bottle at 12.5μM sulfate to 40μl per bottle at 100μM sulfate. The results indicated that heteroexpression of lehemoglaobin genes in chloroplasts of green algae improved H2 yield by decreasing O2 content in the medium. This protein had potential to be used in improvement of H2 production in green algae. [ABSTRACT FROM AUTHOR]