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Identification of geographical origin is of great importance for protecting the authenticity of valuable agri-food products with designated origins. In this study, a robust and accurate analytical method that could authenticate the geographical origin of Geographical Indication (GI) products was developed. The method was based on elemental profiling using inductively coupled plasma mass spectrometry (ICP-MS) in combination with machine learning techniques for model building and feature selection. The method successfully predicted and classified six varieties of Chinese GI rice. The elemental profiles of 131 rice samples were determined, and two machine learning algorithms were implemented, support vector machines (SVM) and random forest (RF), together with the feature selection algorithm Relief. Prediction accuracy of 100% was achieved by both Relief-SVM and Relief-RF models, using only four elements (Al, B, Rb, and Na). The methodology and knowledge from this study could be used to develop reliable methods for tracing geographical origins and controlling fraudulent labeling of diverse high-value agri-food products.

Background Rice is an important staple food that is consumed around the world. Like many foods, the price of rice varies considerably, from very inexpensive for a low-quality product to premium pricing for highly prized varieties from specific locations. Therefore, like other foods it is vulnerable to economically motivated adulteration through substitution or misrepresentation of inferior-quality rice for more expensive varieties. Objective In this article we describe results of a research project focused on addressing potential food fraud issues related to rice supplies in China, India, Vietnam, and Ghana. Rice fraud manifests differently in each country; therefore, tailored solutions were required. Method Here we describe a two-tiered testing regime of rapid screening using portable Near Infrared technology supported by second tier testing using mass spectrometry-based analysis of suspicious samples. Results Portable Near Infrared spectroscopy models and laboratory-based Gas Chromatography-Mass Spectrometry methods were developed to differentiate between: high-value Basmati rice varieties and their potential adulterants; six Geographic Indicated protected rice varieties from specific regions within China; various qualities of rice in Ghana and Vietnam; and locally produced and imported rice in Ghana. Furthermore, an Inductively Coupled Plasma-Mass Spectrometry method was developed to support the Chinese rice varieties methods as well as a Liquid Chromatography Quadrupole Time-of-Flight Mass Spectrometry method for quality differentiation in Vietnam. Conclusions/Highlights This two-tier approach can provide a substantially increased level of testing through rapid screening outside of the laboratory with the reassurance of corroborating mass spectrometry-based laboratory analysis to support decision making.

Combinatorial biosynthesis of 5/5/6 type polycyclic tetramate macrolactams (PoTeMs) was achieved in an engineered ikarugamycin (5/6/5 type) producer by introducing a set of 5/5/6 type PoTeM biosynthetic genes from Streptomyces griseus. This study supports the idea that PoTeMs share a common polyene tetramate precursor generated by the hybrid polyketide synthase/nonribosomal peptide synthetase enzymes. The X-ray crystal structure of pactamide G (7) sets an example for resolving the absolute configuration of 5/5/6 type PoTeMs.

Extracts from Antarctic-derived Penicillium chrysogenum CCTCC M 2020019 showed potent antibacterial bioactivities. We report herein the isolation of chrysonin (1), a new compound containing a pair of enantiomers 6S- and 6R-chrysonin (1a and 1b) featuring an unprecedented eight-membered heterocycle fused with a benzene ring. Compound 2, a mixture consisting of a new zwitterionic compound chrysomamide (2a) and N-[2-trans-(4-hydroxyphenyl) ethenyl] formamide (2b) in a ratio around 1 : 2.8, was isolated together with seven known compounds 3–9. Chemical structures of all compounds were determined by comprehensive spectroscopic analyses. The isolated compounds were evaluated for antimicrobial, cytotoxic and alpha-glucosidase inhibition activities. Chrysonin (1) showed moderate alpha-glucosidase inhibitory activity. The dominant product xanthocillin X (4) displayed potent inhibition activities against Gram-negative pathogens Acinetobacter baumannii, Klebsiella pneumoniae, and Pseudomonas aeruginosa with MIC values at 0.125 μg mL−1. Xanthocillins X (4) and Y1 (5) also showed significant cytotoxicities against four cancer cell lines with IC50 values ranging from 0.26 to 5.04 μM. This study highlights that microorganisms from polar regions are emerging as a new resource for the discovery of natural products combating human pathogens.

The aim of this study was to investigate the impact of mycotoxin binders on the determination of aflatoxins in maize and maize gluten using various analytical methods, including ELISA, HPLC and LC-MS/MS. Three types of commercially available mycotoxin binders, yeast cell wall, mineral, and a mixture of mineral and bacterium, were investigated at inclusion levels of 0.1%, 0.2% and 0.4%. The binders were added to maize and maize gluten contaminated with aflatoxins at concentrations between 6.9 and 26.7 μg kg-1. The samples were analysed and the values were compared with corresponding controls (samples without binders) using ANOVA. The yeast cell wall binder had no significant effect (p=0.05) on the concentration of aflatoxins measured in either maize or maize gluten at any of the three inclusion levels, regardless of which analytical method was used. The mineral binder and the mixed mineral and bacterium binder had no significant effect (p=0.05) on the measured aflatoxin concentrations in either maize or maize gluten at any of the three inclusion levels when analysis was conducted using LC-MS/MS. Inclusion of these binders resulted in significant lower (p

Remote sensing science and technology is a technology for observing the earth from space developed in 1960. After more than half a century of development, remote sensing has become the main means of obtaining space information and is widely used in earth sciences and related fields. Remote sensing has not only been widely used in earth sciences and related fields, but also has expanded from traditional applications to the field of social public services. The increase in image resolution directly leads to a significant increase in the amount of remote sensing data, and the demand for geographic information also increases significantly. The coastal areas are mainly hilly landforms and densely populated cities, resulting in the structure of the overlying atmospheric boundary layer with unique distribution patterns and changing laws, which affects the ability of atmospheric diffusion, sparseness, and removal. Their composition is very complex, and the decomposition process is different from ordinary pollutants. Under difficult terrain and coastal conditions, it is affected by the particularity of boundary layer turbulence and related meteorological processes. Their concentration shows the complex characteristics of time and space distribution. As the economy grows, people’s demand for cars is also increasing. For companies with different types of vehicles, vehicle management has become an important task in company activities. The challenge for companies is to understand the driver’s condition in time, take reasonable steps to drive, use the vehicle, provide information about the use of the vehicle, and reduce maintenance costs.

Knowledge on the distribution of plankton species is fundamental to understand planktonic ecosystem structure and function. To understand the difference of tintinnid vertical distribution pattern in the Bering Sea and the Arctic Ocean and their connection through the Bering Strait, we reported the vertical distribution of tintinnid assemblages from the Bering Sea to the Arctic Ocean. Bering Sea-dominant species (Codonellopsis frigida, Ptychocylis obtusa, Parafavella spp., Acanthostomella norvegica) had abundance peak in the upper 50 m. In the Arctic Ocean, abundance peak of dominant species (P. urnula) occurred in surface and deep chlorophyll a maximum layers. Salpingella acuminata and S. faurei occurred from 50 to 80 m in Bering Sea and Arctic Ocean oceanic waters. Bering Strait-dominant species (P. acuta, Parafavella spp., A. norvegica) occurred from the surface to the bottom. Both S. acuminata and S. faurei were absent in Bering Strait at depths shallower than 120 m. Bering Sea-dominant species (C. frigida, P. obtusa, Parafavella spp., A. norvegica) disappeared successively northward. Ptychocylis urnula occurred in the northern part of Bering Strait at depths exceeding 50 m. The size of P. acuta (only occurring in Bering Strait) was between that of P. urnula and P. obtusa. Bering Sea-dominant species had wide temperature but narrow salinity ranges (32.7–33.3); their successive northward disappearance might reflect difference in the salinity tolerance. Ptychocylis urnula had a wide salinity but narrow temperature range in the Arctic Ocean. Its distribution through Bering Strait is likely limited by temperature (− 1.8 to 1.2 °C). The vertical distribution of S. acuminata and S. faurei might correlate with depth. Our results contribute to a better understanding of the vertical distribution of the microbial food web and serve as a baseline for future studies on the pelagic community change in the Arctic.

As mariculture expands offshore in response to the increasing demand for seafood, a new set of ecological concerns arises. We report on presented phosphate and silicate deficiencies in spring in the Zhangzi Island area, northern Yellow Sea, used for farming scallops. Silicon limitation was observed at up to 77.3% of stations, with an average silicate concentration as low as 1.7 μM in March 2014. Average phosphate concentration decreased from 0.12 to 0.05 μM from March to May. Stoichiometric ratios and absolute concentrations indicate that 78%–90% of stations showed phosphate limitation. Correspondingly, the phytoplankton community shifted from predominately diatoms to dinoflagellates. The higher frequency of nutrient limitation in farmed areas, compared with unseeded areas and northern Yellow Sea in general, imply intensified bottom-up controls on scallop production. The “bottle-neck” effect of limited food availability in spring suggests that carrying capacity was originally overestimated, when calculated from annual primary production.

Today, most students in coastal cities in China were born after the 1990s. They have been spoiled by the older generation since they were young. They grew up under the protection of their parents. Most of them are flowers in the greenhouse. Now, they have entered the university, carrying the double expectations of society and family. All these pressures, such as learning knowledge, improving skills, etc., come and make them feel confused. Strong self-esteem, personal resistance, and more or less selfish combination of these factors have a huge impact on the psychology of students in coastal cities. In view of the current situation, this article expounds the importance of mental health education for students in coastal cities, clarifies the current problems and causes of mental health in colleges and universities, and puts forward countermeasures and suggestions to solve these problems. The corresponding drop in seawater temperature is an important thermodynamic index that affects coastal climate. This paper selects the environmental climate data of a given coast at 21 locations on a given coast from 1972 to 2020, combines the intermediate data of ERA, and uses a comprehensive analysis method to study the climatic characteristics of sea fog on a given coast. Two dates in ERA-Interim and ICOADS were used to compare and analyze the spatial distribution of coastal sea temperature field from 1984 to 2018 and the temporal and spatial distribution characteristics of coastal marine climate environment. Based on artificial intelligence algorithms, this article successfully optimized the original prediction model and effectively improved the prediction accuracy of the model. The final forecasting model can not only be applied to forecasting, but also because after improving it, it can make efficient and highly accurate forecasts based on a wide range of economic and other fields of data.

The fungus strain SCSIO 40433 was isolated from an Arctic-derived glacier sediment sample and characterized as Tolypocladium cylindrosporum. A new compound, cylindromicin (1), and seven known secondary metabolites (2–8) were isolated from this strain. The chemical structures of these compounds were elucidated by comprehensive spectroscopic analyses. Cylindromicin (1) featured a 3,4-dihydro-2H-pyran skeleton. The absolute configuration of compound 1 was assigned via interpretation of key Nuclear Overhauser Effect Spectroscopy (NOESY) correlations and Electronic Circular Dichroism (ECD) calculation. Cylindromicin (1) exhibited significant tyrosinase inhibition activity. This study highlights Polar fungi as a potential resource for new bioactive natural products.

In this study, an ELISA-based method was observed to overestimate quantification of peanut in three wheat flour-based dry matrices (both raw and cooked). A reliable method using liquid chromatography tandem mass spectrometry (LC-MS/MS) was developed to quantify peanut accurately in these matrices. This method simplified both sample preparation and quantification compared with previous approaches, by digesting peanut proteins without reduction and alkylation and using Ara h 1 to build calibration curves. A significantly increased amount of peanut peptides was detected by heating the extracts. The sensitivity and linearity were superior to most commercial ELISA kits. The limit of quantification (LOQ) was 0.31 mg/kg total peanut in wheat flour and the linear range was between 0.3 and 40 mg/kg. This LC-MS/MS method could be applied as a confirmatory method for peanut allergen management when positive ELISA results raise suspicion of contamination.

Polycyclic tetramate macrolactams (PTMs) are widely distributed in nature and are generated from a compact biosynthetic pathway. Bioinformatics analysis of the draft genome sequence of marine-derived Streptomyces sp. SCSIO 40060 revealed the presence of a putative PTM-encoding biosynthetic gene cluster (BGC). Comparison of this PTM BGC with those from the databank by genome mining suggests that Streptomyces sp. SCSIO 40060 should produce PTMs with a 5/6/5 type of carbocyclic ring. Subsequently, a 40-L scale of cultivation of Streptomyces sp. SCSIO 40060 led to the isolation and characterization of four known PTMS, ikarugamycin (1), epoxyikarugamycin (2), capsimycin (3), capsimycin C (4), and three new PTMs, hydroxyikarugamycins A–C (5–7). The planar structures of 5–7 were assigned by comprehensive spectroscopic analysis and the absolute configurations of 5 and 6 were unequivocally determined by X-ray diffraction analysis. The absolute structure of 7 was deduced by comparing ECD spectra of 5–7. Capsimycin (3) showed antimicrobial activity against methicillin-resistant Staphylococcus aureus with a MIC value of 16 μg/mL and displayed cytotoxicity against several cancer cell lines with IC50 values ranging from 2.62 to 6.87 μM.

Zooplankton abundance, biovolume and taxonomic composition in Jiaozhou Bay and the adjacent coastal Yellow Sea were evaluated using ZooScan measurement of samples collected by net towing every August from 2005 to 2012. Zooplankton abundance and biovolume ranged from 1 938.5 to 24 800 ind./ m3 and 70.8 to 1 480.1 mm3 /m3 in Jiaozhou Bay and 73.1 to 16 814.3 ind./m3 and 19.6 to 640.7 mm3 /m3 in the coastal Yellow Sea. Copepods were the most abundant group in both regions, followed by Noctiluca scintillans and appendicularians in Jiaohzou Bay, and chaetognaths and Noctiluca scintillans in adjacent coastal Yellow Sea. Over the study period, the most conspicuous hydrographic change was an increase in water temperature. Meanwhile, a general decrease in zooplankton abundance was observed, particularly in copepod populations. Based on redundancy analysis (RDA), the warming trend was the key environmental factor influencing to decrease of copepod abundance. The proportion of small-sized copepods increased while the mean size of all copepods decreased, in significant correlation with water temperature. Our results indicate that zooplankton, particularly copepods, are highly sensitive to change in water temperature, which is consistent with predicted impacts of warming on aquatic ectotherms. Due to their dominance in the zooplankton, the decline in copepod size and abundance could lead to an unfavourable decrease in energy availability for predators, particularly planktivorous fish.

Much has been written on annual variation of tintinnid assemblages although the mechanism causing the annual variation has been poorly studied either in form of species richness or Lorica Oral Diameter (LOD) size-classes. In the present study, a 10-year (May 2003 to December 2012) survey on species occurrence, abundance, and LOD variation of the tintinnid ciliates was conducted in Jiaozhou Bay, western Pacific. In contrast to previous studies, we found summer peaks in tintinnid species richness in Jiaozhou Bay validated by multi-year investigations. We studied phenology of every tintinnid species and explored the mechanism causing the annual variation. The hypothesis was that tintinnid species richness has a winter baseline, to which warm water species added with the progress of the season. We defined the occurrence types of each species, and found there was only one cold occurrence type species. There was no overlap of cold occurrence type and warm occurrence type in the transitional period between winter and summer. The second aim of this study was to explore annual variations in tintinnid assemblages in form of LOD and redundant species. The species frequency distribution patterns among LOD size-classes were similar all year round. The abundance frequency distribution pattern in LOD size-classes could be divided into two phases: cold phase and warm phase with exception of May and September. The portion of redundant species was about 50% in every month. Our result help understand and predict annual variation of tintinnid assemblages in terms of species richness and LOD in world oceans.

Seasonal variations in numerical abundance, cell diameter and population carbon biomass of the heterotrophic dinoflagellate Noctiluca scintillans were studied for 10 years from 2004 to 2013 in Jiaozhou Bay and adjacent coastal Yellow Sea, China, and their ecological functions were evaluated. In both areas, N. scintillans occurred throughout the year and demonstrated an essentially similar seasonality; the cell abundance increased rapidly from the winter minimum to an annual peak in late spring and early summer, and decreased gradually toward the autumn-winter minimum. The peak abundance differed by years, and there was no consistent trend in long-term numerical variations. The cell diameter also showed a seasonal fluctuation, being larger in spring and early summer than the other seasons. Estimated carbon biomass of N. scintillans population reached to a peak as high as 90.3 mg C/m3, and occasionally exceed over phytoplankton and copepod biomass. Our results demonstrate that N. scintillans in northwestern Yellow Sea displays the seasonal phenology almost identical to the populations in other temperate regions, and play important trophic roles as a heterotroph to interact with sympatric phytoplankton and copepods.

The reaction of enamine compounds with the Togni reagent in the presence of CuI afforded β-trifluoromethylated enamine intermediates, which were converted directly to biologically interesting trifluoromethylated 2H-azirines by an iodosobenzene (PhIO)-mediated intramolecular azirination in a one-pot process.

Ice decline is believed to benefit the pelagic food chain in Arctic shelf ecosystems, but the impacts of ice decline are usually difficult to detect owing to the overlap of ice decline with natural variability. To evaluate the responses of zooplankton communities to sea ice reduction in the Chukchi Sea, we combined zooplankton samples collected in the early summers of 2003, 2008, 2010, and 2012 and compared the inter-annual changes in the subregions with various physical and biological characteristics. Three geographically separate communities were identified by a hierarchical cluster analysis. The Bering Sea water influenced the central (CCS) and south (SCS) Chukchi Sea communities, which had total abundances that were approximately ten times higher than that of the north (NCS) Chukchi Sea community, and the inter-annual variability was dramatic. The SCS and CCS shared dominant taxa of Calanus glacialis, Pseudocalanus spp., barnacle larvae (nauplii and cypris), and Oikopleura vanhoffeni, while Pacific and neritic species were recognized as the dominant species in only the SCS. The inter-annual variations in the dominant species assemblages can be explained by the variability in oceanic circulation and the counteractions between copepods and barnacle larvae. Despite the numerical fluctuations, an increase in the average abundances in the Pacific-influenced region and the summer establishment of the C. glacialis population are proposed to be the most pronounced responses to ice decline. The NCS, which is governed by cold Arctic water, was characterized by low abundances and a constant dominant taxa assemblage. This area was also characterized by the presence of the high Arctic species Calanus hyperboreus and a lack of barnacle larvae. The total abundance of the NCS doubled from 2003 to 2008, while the community structure remained consistent. These results indicate that sea ice reduction has a positive effect on the zooplankton community, but heterogeneity is the main obstacle to the detection of the zooplankton community in the Western Arctic Ocean.

Picoplankton distribution around the Zhangzi Island (northern Yellow Sea) was investigated by monthly observation from July 2009 to June 2010. Three picoplankton populations were discriminated by flow cytometry, namely Synechococcus, picoeukaryotes and heterotrophic prokaryotes. In summer (from July to September), the edge of the northern Yellow Sea Cold Water Mass (NYSCWM) resulting from water column stratification was observed. In the NYSCWM, picoplankton (including Synechococcus, picoeukaryotes and heterotrophic prokaryotes) distributed synchronically with extremely high abundance in the thermocline (20 m) in July and August (especially in August), whereas in the bottom zone of the NYSCWM (below 30 m), picoplankton abundance was quite low. Synechococcus, picoeukaryotes and heterotrophic prokaryotes showed similar response to the NYSCWM, indicating they had similar regulating mechanism under the influence of NYSCWM. Whereas in the non-NYSCWM, Synechococcus, picoeukaryotes and heterotrophic prokaryotes exhibited different distribution patterns, suggesting they had different controlling mechanisms. Statistical analysis indicated that temperature, nutrients (NO3– and PO43–) and ciliate were important factors in regulating picoplankton distribution. The results in this study suggested that the physical event NYSCWM, had strong influence on picoplankton distribution around the Zhangzi Island in the northern Yellow Sea.

Shelf-basin advection is essential to subsistence of the Arctic copepod Calanus hyperboreus population in high basin area. Its abundance, population structure and body size in pelagic layer were investigated with samples collected over a large range in the western Arctic Ocean during summer 2003, to evaluate the geographical variation in recruitment pattern. Calanus hyperboreus was absent from the shallow areas of the Chukchi Sea and most abundant in the slope area between the Chukchi Sea and Chukchi Abyssal Plain (CS-slope). Total abundance varied between 1 110.0 and 5 815.0 ind./m2 in the CS-slope area and ranged from 40.0 to 950.0 ind./m2 in the other areas. Early stages (CI–IV) dominated in the CS-slope area, whereas CV and adult females were frequently recorded only in deep basin areas. Geographical difference of prosome length was most evident in CIII, with average ranging from 2.48 to 2.61 mm at the CS-slope stations and 2.16–2.37 mm at the others. Abundance of early developmental stages (CI–CIV) correlated positively with Chl a concentration, but negative correlation was observed in late stages (CV–adult). Our results indicated that C. hyperboreus can benefit from primary production increase through accelerated development in the first growth season and the productive CS-slope area is a potential source for slope-basin replenishment.

A new oxidative system of tert-butyl hydroperoxide (TBHP)/azodiisobutyronitrile (AIBN) has been used for the first time for a convenient, metal-free synthesis of substituted 2-aminothioazoles from active methylene ketone derivatives and thiourea. The reaction is postulated to proceed via an oxidative cyclization initiated by a radical process and followed by a condensation reaction.

Studies of strobilation of scyphozoan polyp populations in the field are essential for determination of the natural seasonal period of ephyra release and for predicting the size of medusa populations, but they have rarely been conducted. We set up experimental polyp colonies of 3 scyphozoans (Aurelia coerulea, Nemopilema nomurai, Rhopilema esculentum) on settling plates in Jiaozhou Bay, China, and monitored them at 2-7 d intervals for 8 mo (December 2012 to August 2013). Polyps of A. coerulea survived, even proliferating by budding during the entire period, while those of N. nomurai and R. esculentum experienced high mortality and died out after strobilation. Strobilation in all 3 species occurred from late winter to early summer, but the exact timing, duration, frequency, strobilation percentage, and disc numbers strobila(-1) differed by species. A. coerulea started strobilation earliest, on 25 February (temperature: 3.9 degrees C), and persisted for 105 d until 9 June (18.1 degrees C). N. nomurai strobilated from 28 March to 9 June (6.4-18.1 degrees C), with some performing a second, less conspicuous strobilation from 6 May to 9 June (12.0-18.1 degrees C). R. esculentum strobilated last, from 15 April to 8 July (9.0-21.5 degrees C). Greater polyp population resilience in A. coerulea over N. nomurai and R. esculentum can be attributed, at least in part, to persistent propagation by budding, which may facilitate the annually recurring medusa blooms of A. coerulea observed in the region. The latter 2 species may give rise to medusa blooms only when their vulnerable polyps have survived well. Due to the later strobilation, R. esculentum ephyrae may be susceptible to competition for food with and predation by post-ephyra stages of A. coerulea and N. nomurai.

The use of bivalve aquaculture to mitigate eutrophication in coastal waters has been proposed for years. As nitrogen overenrichment is usually accompanied by comparative shortages in silicate and phosphate, bivalve cultivation integrated with artificial fertilization may exhibit better nitrogen removal performance than bivalve cultivation alone. During a 15-day mesocosm experiment in a nitrogen-eutrophicated, phosphate-limited coastal pond, the nitrogen fixation in oyster tissue under rice husk ash (RHA)1 fertilized conditions was 10 times higher than that in the oyster-only treatments with the same density. Meanwhile, the concentrations of dissolved inorganic nitrogen (DIN) and particulate nitrogen (PN) in the combined oyster-fertilization treatments decreased by 87.0% and 57.2%, respectively. Compared with the RHA fertilization treatments, the net DIN consumption was significantly lower and decreased with the oyster density in the oyster-only treatments. The dissolved N/Si ratio decreased from 1.44 to 1.01 and 0.93 in the control and fertilization treatments, respectively, whereas in the oyster-only treatments, it increased to 3.74 at low density and 29.15 at high density. Our results indicate that oyster cultivation can stimulate the regeneration of nitrogen in dissolved forms and intensify relative silicate shortages. The integration of RHA fertilization mediated silicate shortage and helped maintain a balanced dissolved N/Si ratio. Moreover, the combined oyster-RHA fertilization enhanced nitrogen removal efficiency and biomass accumulation and increased the feasibility of oyster cultivation as a cost-effective nitrogen reduction measure.

Polycyclic tetramate macrolactams (PTMs) are a growing class of natural products and are derived from a hybrid polyketide synthase (PKS)/non-ribosomal peptide synthetase (NRPS) pathway. PTM biosynthetic gene clusters are conserved and widely distributed in bacteria, however, most of them remain silent. Herein we report the activation of a PTM gene cluster in marine-derived Streptomyces pactum SCSIO 02999 by promoter engineering and heterologous expression, leading to the discovery of six new PTMs, pactamides A-F (11-16), with potent cytotoxic activity upon several human cancer cell lines. In vivo gene disruption experiments and in vitro biochemical assays reveal a reductive cyclization cascade for polycycle formation, with reactions sequentially generating the 5, 5/5 and 5/5/6 carbocyclic ring systems, catalysed by the phytoene dehydrogenase PtmB2, the oxidoreductase PtmB1, and the alcohol dehydrogenase PtmC, respectively. Furthermore, PtmC was demonstrated as a bifunctional cyclase for catalyzing the formation of the inner five-membered ring in ikarugamycin. This study suggests the possibility of finding more bioactive PTMs by genome mining and discloses a general mechanism for the formation of 5/5/6-type carbocyclic rings in PTMs.

Samples were collected monthly from the sea area around Zhangzi Island, northern Yellow Sea, from July 2009 to June 2010. Vertical net towing was used to examine spatial and temporal variability in zooplankton abundance and biomass. Overall, Calanus sinicus and Saggita crassa were the dominant species found during the study period, while the amphipod Themisto gracilipes was dominant in winter and spring. Vast numbers of the ctenophore species of the genus Beroe were found in October and November. It was not possible to count them, but they constituted a large portion of the total zooplankton biomass. Zooplankton species diversity was highest in October, and species evenness was highest in April. Zooplankton abundance (non-jellyfish) and biomass were highest in June and lowest in August, with annual averages of 131.3 ind./m³ and 217.5 mg/m³, respectively. Water temperature may be responsible for the variations in zooplankton abundance and biomass. Beroe biomass was negatively correlated with other zooplankton abundance. Longterm investigations will be carried out to learn more about the influence of the environment on zooplankton assemblages.

Polycyclic tetramate macrolactams (PTMs) biosynthetic gene cluster are widely distributed in different bacterial types, especially in Streptomyces species. The mining of the genomic data of marine-derived Streptomyces sp. SCSIO 40010 reveals the presence of a putative PTM-encoding biosynthetic gene cluster (ptm&prime, BGC) that features a genetic organization for potentially producing 5/5/6 type of carbocyclic ring-containing PTMs. A fermentation of Streptomyces sp. SCSIO 40010 led to the isolation and characterization of six new PTMs 1&ndash, 6. Comprehensive spectroscopic analysis assigned their planar structures and relative configurations, and their absolute configurations were deduced by comparing the experimental electronic circular dichroism (ECD) spectra with the reported spectra of the known PTMs. Intriguingly, compounds 1&ndash, 6 were determined to have a trans-orientation of H-10/H-11 at the first 5-membered ring, being distinct from the cis-orientation in their known PTM congeners. PTMs 1&ndash, 5 displayed cytotoxicity against several cancer cell lines, with IC50 values that ranged from 2.47 to 17.68 &micro, M.

Background Reports of incidents associated with the misrepresentation of food products as well as the adulteration of their composition leading, at times, to significant public health impacts are being recorded. Objective This paper aims at summarizing the outputs of three workshops dedicated to the theme “Global Understanding of Food Fraud” (GUFF), held in Quebec City in Canada (April 2017), Beijing in the People’s Republic of China (October 2017) and Dubai in the United Arab Emirates (October 2018). Method Based on the contributions made at these workshops, the paper reviews current knowledge related to food fraud shared by experts and stakeholders representing the food industry sector, food regulators both domestically and internationally and scientists from Academia. It also discusses approaches available to the industry across the food supply chain to predict, prevent, and possibly mitigate food fraud, inclusive of targeted and non-targeted methods of analysis. Results and Conclusions The paper offers a discussion on areas warranting the mobilization of efforts and resources of the food stakeholder community to reach consistent and accessible guidance on food fraud prevention, validated analytical methods along with an increased emphasis on prevention in food regulatory measures targeting food fraud. Further development is needed to reach consistent and accessible guidance on food fraud prevention, validated analytical methods, along with an emphasis on food fraud prevention. Highlights Food fraud is receiving increased attention from consumers, regulators, and industry. International food fraud experts were invited to three workshops. Contributions and conclusions from the workshops are reported and discussed.

The spatial variation in size structure of mesozooplankton and its relationship with environmental factors were studied from January 2006 to December 2010 in Jiaozhou Bay. The spatial body-size patterns of zooplankton differed significantly from the inner to the outer bay, and have a significant correlation with environmental variables, especially nutrients, salinity and water depth. The abundance of total zooplankton and small size ranks presented a decreasing gradient from the inner to the outer part, and was positive correlated with nutrients and negative with salinity, while the abundance of large size ranks exhibited an opposite gradient, and was positive correlated with water depth and negative with nutrients. The size spectra slope and size diversity were generally low in the inner part and closely related to body size ranks. Our results suggest that size structure patterns of zooplankton showed a clear spatial pattern and significantly associated with environmental factors in marine ecosystems.

A ctenophore Pleurobrachia globosa Moser, 1903, recognized as a warm water species, showed abrupt population rise since the year 2000 in a temperate bay–the Jiaozhou Bay (JZB), a coastal bay in northern China, >1100 km north from the reported native habitat. Using hundreds of surveys in the JZB and the adjacent Yellow Sea (YS), we examined the population fluctuations over the recent 20 years, possible links between abundance and environmental factors, and the reproductive strategies. In the JZB, P. globosa mainly appeared from August to December each year, reaching the maximum abundance of 170 ind. m−3 in August 2008. A general warming trend continues in the JZB during the recent two decades, with the alternating of warm and cool periods. Temperature is recognized as a primary driver of abundance variations, with significantly higher abundance levels in warmer years than in cooler years. The population uses either larval reproduction or adult reproduction almost exclusively in the JZB, with unknown mechanisms. High abundance can result from both reproductive strategies. Larval reproduction distinguishes itself from adult reproduction by significantly smaller parent size, egg size and clutch size, explaining the short-size dominated population in several surveys. Clutch size is positively related to body size and temperature. The geographical range of the YS population reached to ~39°N in June 2014, indicating a northward expansion since the late 1990s, together with other evidences from the JZB and the Bohai Sea. While the successful establishment could be driven primarily by warming, lack of competitors and predators as well as the particular life history strategies also contributed. Issues of the vectors for introduction, local overwintering population, and regulatory mechanism of reproductive strategy need to be addressed in further studies.

In this study, the complete mitochondrial genome of Graphium doson was recovered through Illumina sequencing data. This complete mitochondrial genome of G. doson is 15,285 bp in length and has a ba...

The aim of this paper is to develop a boundary control for attenuating the vibration of a flexible beam and string system in the presence of input restriction. To this end, a boundary control is developed to attenuate the vibration and mitigate the effect of the restricted input employing smooth hyperbolic tangent function. Under the proposed control, the stability of the controlled system is achieved through rigorous analysis without resorting to discretization of the system infinite-dimensional model, and the controlled system is ensured to be asymptotically stable. Finally, the simulations verify the results.

Tryptophan dimers (TDs) are an important class of natural products with diverse bioactivities and share conserved biosynthetic pathways. We report the identification of a partial gene cluster (spm) responsible for the biosynthesis of a class of unusual TDs with non-planar skeletons including spiroindimicins (SPMs), indimicins (IDMs), and lynamicins (LNMs) from the deep-sea derived Streptomyces sp. SCSIO 03032. Bioinformatics analysis, targeted gene disruptions, and heterologous expression studies confirmed the involvement of the spm gene cluster in the biosynthesis of SPM/IDM/LNMs, and revealed the indispensable roles for the halogenase/reductase pair SpmHF, the amino acid oxidase SpmO, and the chromopyrrolic acid (CPA) synthase SpmD, as well as the positive regulator SpmR and the putative transporter SpmA. However, the spm gene cluster was unable to confer a heterologous host the ability to produce SPM/IDM/LNMs. In addition, the P450 enzyme SpmP and the monooxygenase SpmX2 were found to be non-relevant to the biosynthesis of SPM/IDM/LNMs. Sequence alignment and structure modeling suggested the lack of key conserved amino acid residues in the substrate-binding pocket of SpmP. Furthermore, feeding experiments in the non-producing ΔspmO mutant revealed several biosynthetic precursors en route to SPMs, indicating that key enzymes responsible for the biosynthesis of SPMs should be encoded by genes outside of the identified spm gene cluster. Finally, the biosynthetic pathways of SPM/IDM/LNMs are proposed to lay a basis for further insights into their intriguing biosynthetic machinery.

Lysine acetylation regulates gene expression through modulating protein-protein interactions in chromatin. Chemical inhibition of acetyl-lysine binding bromodomains of the major chromatin regulators BET (bromodomain and extra-terminal domain) proteins, has been shown to effectively block cell proliferation in cancer and inflammation. However, whether selective inhibition of individual BET bromodomains has distinctive functional consequences, remains only partially understood. In this study, we show that selective chemical inhibition of the first bromodomain of BET proteins using our newly designed small molecule inhibitor, Olinone, accelerated the progression of mouse primary oligodendrocyte progenitors towards differentiation, while inhibition of both bromodomains of BET proteins hindered differentiation. This effect was target-specific, as it was not detected in cells treated with inactive analogues and independent of any effect on proliferation. Therefore, selective chemical modulation of individual bromodomains, rather than use of broad-based inhibitors may enhance regenerative strategies in disorders characterized by myelin loss such as aging and neurodegeneration.

Large-scale macro-algal blooms ofUlva prolifera(also called green tides) have appeared each summer since 2008 in the western Yellow Sea. In this study, we investigated the temporal variability in zooplankton community in the western Yellow Sea and its possible links to green tides using data from a long-term plankton survey off the coast of Qingdao, China. Environmental conditions observed in the study area during the green tide period (GTP: June–August, 2008–2013) were compared to the non-green tide period (NGTP: June–August, 2005–2007), to support the contention that variations observed in zooplankton community may be attributed to the green tides, as opposed to natural climatic or environmental variations. Zooplankton assemblage structure observed during the GTP was then compared to the NGTP. Significant variations were detected both in zooplankton abundance and assemblage structure between the two defined periods. The abundance of zooplankton, mainly copepods, was significantly decreased during the GTP. Meanwhile, the relative abundance of copepods decreased by approximately 10% and that of gelatinous zooplankton, including appendicularians, chaetognaths, and medusae, almost doubled (ca. increased by 6.4%). The dominant species of meroplankton completely changed, specifically, polychaeta, and echinoderm larvae were more dominant than decapod and bivalve larvae. With regard to zooplankton size structure, the NGTP showed a higher size diversity with more small-sized organisms, while the GTP showed a lower size diversity in the community. According to general linear models, the interannual variation in summer zooplankton abundance was significantly correlated with green tides. These results indicate that the temporal changes in zooplankton community may have a close link to the green tides.

An increase in marine artificial constructions has been proposed as a major cause of jellyfish blooms, because these constructions provide additional substrates for organisms at the benthic stage (polyps), which proliferate asexually and release a large amount of free-swimming medusae. These hard surfaces are normally covered by fouling communities, the components of which have the potential to impede the proliferation of polyps. In this study, we report an in situ experiment of polyp survival of four large scyphozoan species found in East Asian marginal seas that were exposed to biofouling, a universal phenomenon occurring on marine artificial constructions. Our results showed that the polyps of three species (Nemopilema nomurai, Cyanea nozaki, and Rhopilema esculentum) attached to the artificial surfaces were completely eliminated by biofouling within 7-8months, and only those of moon jellyfish (Aurelia sp.1) in the upper layers could multiply on both artificial materials and other organisms (e.g., ascidians and bryozoans). Fouling-associated competition and predation and suppressed asexual reproduction of podocysts were observed to contribute to the loss of polyps. This study shows that the natural distribution of polyps is defined by the biofouling community that colonizes the surfaces of artificial constructions. Consequently, the contribution of marine constructions to jellyfish bloom is limited only to the ability of the jellyfish species to reproduce asexually through budding and inhabit solid surfaces of fouling organisms in addition to inhabiting original artificial materials. We anticipate that fragile polyps will colonize and proliferate in harsh environments that are deleterious to biofouling, and we propose special attention to polyps in antifouling practices for excluding the possibility that they occupy the available ecological space.

Tintinnids are planktonic ciliates that play an important role in marine ecosystem. According to their distribution in the world oceans, tintinnid genera were divided into several biogeographical types such as boreal, warm water, austral and neritic. Therefore, the oceanic tintinnid assemblage could be correspondingly divided into boreal assemblage, warm water assemblage and austral assemblage. The purpose of this study was to investigate the characteristics of boreal tintinnid assemblage in the Northwest Pacific and the Arctic, and to identify the connection between boreal tintinnid assemblage and neighboring assemblages. Surface water samples were collected along a transect from the East China Sea to the Chukchi Sea in summer 2014. According to the presence of boreal genera and warm water genera, three tintinnid assemblages (the East China Sea neritic assemblage, the Japan Sea warm water assemblage, and the boreal assemblage) were identified along the transect. The boreal assemblage extended from the Chukchi Sea to the waters north of the Soya Strait. Densities peaks occurred at stations in the two branches of the Alaska Current and decreased both northward and southward. The densities were

Caerulomycin A (CRM A 1) belongs to a family of natural products containing a 2,2'-bipyridyl ring core structure and is currently under development as a potent novel immunosuppressive agent. Herein, we report the functional characterization, kinetic analysis, substrate specificity, and structure insights of an aminotransferase CrmG in 1 biosynthesis. The aminotransferase CrmG was confirmed to catalyze a key transamination reaction to convert an aldehyde group to an amino group in the 1 biosynthetic pathway, preferring l-glutamate and l-glutamine as the amino donor substrates. The crystal structures of CrmG in complex with the cofactor 5'-pyridoxal phosphate (PLP) or 5'-pyridoxamine phosphate (PMP) or the acceptor substrate were determined to adopt a canonical fold-type I of PLP-dependent enzymes with a unique small additional domain. The structure guided site-directed mutagenesis identified key amino acid residues for substrate binding and catalytic activities, thus providing insights into the transamination mechanism of CrmG.

Polycyclic tetramate macrolactams (PTMs), a widely distributed class of structurally complex natural products exhibiting diverse biological activities, share a tetramate-containing macrocyclic lactam ring fused to a subset of carbocyclic rings. More than 30 naturally occurring PTM members have been reported. Representative members include ikarugamycin, HSAF, and alteramides. The emerging significance of PTMs in medicinal applications has raised attentions on their biosynthetic studies. These studies have unveiled the unexpected conservation of compact PTM biosynthetic loci in phylogenetically diverse bacteria and elucidated mechanisms for key steps in PTM biosynthesis. PTMs were demonstrated to be derived from the common origin of a hybrid polyketide synthase (PKS)/nonribosomal peptide synthetase (NRPS) pathway, in which the PKS portion was iteratively used to generate two separate polyketide chains. A common tetramate-containing polyene intermediate was proposed to be the final product of all PTM PKS/NRPS assembly lines. Subsequently, a set of oxidoreductases acted in a not yet clearly understood way to dictate the manner of cyclizations to yield different polycycle ring systems in PTMs. The only well studied example was the formation of the inner fivemembered ring in ikarugamycin, which was catalyzed by an alcohol dehydrogenase via a [1 + 6] Michael addition. Nonetheless, these studies have illustrated the extraordinary simplicity of nature's art in the biosynthesis of PTMs with complex structures and paved the way to further expand the structural diversity of the family of medicinally relevant PTMs by genome mining and combinatorial biosynthesis.