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Articles Corrected proof have been peer-reviewed and accepted, which are not yet assigned to volumes/issues, but are citable by Digital Object Identifier (DOI).
Research Paper
Cultivation of gut microorganisms of the marine ascidian Halocynthia roretzi reveals their potential roles in the environmental adaptation of their host
Yang Yang, Yuting Zhu, Haiming Liu, Jiankai Wei, Haiyan Yu, Bo Dong
, Available online  , doi: 10.1007/s42995-022-00131-4
Abstract(84) HTML PDF Springerlink
It has long been known that abundant symbiotic bacteria exist in the tunic and gut of marine ascidians, and that these play crucial roles in host development, physiological metabolism, and environmental adaptation. However, the identity, roles and functions of these symbiotic bacteria are known for only a few strains. In this study, we isolated and cultivated 263 strains of microorganisms from the intestine of the marine ascidian Halocynthia roretzi through a combination of aerobic and anaerobic culture approaches. Most cultivated species, both aerobic and anaerobic, from ascidian stool samples belonged to the genus Bacillus based on 16S rDNA sequencing identification and phylogenetic assays. The distribution of cultured bacteria varied with seasonal changes in environmental conditions. To explore the functions of cultured bacteria, we screened out a strain of Serratia sp. whose extracts showed high antibacterial activity against aquatic pathogens. These findings revealed the potential roles of gut microorganisms in ascidian defense and environmental adaptation, thus providing insights into the interaction and co-evolution between gut bacteria and their hosts.
Integrative studies on the taxonomy and molecular phylogeny of four new Pleuronema species (Protozoa, Ciliophora, Scuticociliatia)
Mingjian Liu, Yujie Liu, Tengteng Zhang, Borong Lu, Feng Gao, Jing Gu, Saleh A. Al-Farraj, Xiaozhong Hu, Weibo Song
, Available online  , doi: 10.1007/s42995-022-00130-5
Abstract(86) HTML PDF Springerlink
The ciliate genus Pleuronema comprises approximately 30 nominal species and has been reported in freshwater, brackish water, and marine habitats. Nevertheless, recent studies have indicated that there might be a large undiscovered species diversity. In the present work, four new Pleuronema species, namely P. foissneri sp. nov., P. parasmalli sp. nov., P. parasalmastra sp. nov., and P. paraorientale sp. nov., collected from Shenzhen, southern China, was investigated using taxonomic methods. The diagnosis, description, comparisons with morphologically related species and detailed morphometric data are supplied for each. The small subunit ribosomal RNA (SSU rRNA) gene of the four new species is sequenced and their molecular phylogeny is analyzed. The SSU rRNA gene tree shows that Pleuronema is polyphyletic comprising several separate clades. All four new species cluster consistently with P. orientale KF206429, P. puytoraci KF840520 and P. setigerum FJ848874 within the core Pleuronematidae+Peniculistomatidae clade. Phylogenies of Pleuronematidae-related taxa are also discussed.
An efficient method for chitin production from crab shells by a natural deep eutectic solvent
Wen-Can Huang, Dandan Zhao, Changhu Xue, Xiangzhao Mao
, Available online  , doi: 10.1007/s42995-022-00129-y
Abstract(28) HTML PDF Springerlink
Crab shells are an important feedstock for chitin production. However, their highly compact structure significantly limits their use for the production of chitin under mild conditions. Here, a green and efficient approach using a natural deep eutectic solvent (NADES) to produce chitin from crab shells was developed. Its effectiveness in isolating chitin was investigated. The results showed that most proteins and minerals were removed from crab shells and the relative crystallinity of the isolated chitin reached 76%. The quality of the obtained chitin was comparable to chitin isolated by the acid–alkali method. This is the first report on a green method for efficient chitin production from crab shells. This study is expected to open new avenues for green and efficient production of chitin from crab shells.
Hypolipidemic effect of chromium-modified enzymatic product of sulfated rhamnose polysaccharide from Enteromorpha prolifera in type 2 diabetic mice
Xinyu Wang, Han Ye, Jiefen Cui, Yongzhou Chi, Ruizhi Liu, Peng Wang
, Available online  , doi: 10.1007/s42995-022-00127-0
Abstract(52) HTML PDF Springerlink
Sulfated rhamnose polysaccharide (SRP) derived from Enteromorpha prolifera is a metal-ion chelating agent that could potentially be used to treat diabetes. The aim of our study was to determine the effect of a variant of SRP on DIABETES. First, we synthesized and characterized SRPE-3 chromium(Ⅲ) [SRPE-3-Cr(Ⅲ)] complex using an enzymatic method. The maximum chelation rate was 18.2% under optimal chelating conditions of pH 6.0, time 4 h, and temperature 60 ℃. Fourier transform infrared spectroscopy results showed important sites for Cr(Ⅲ)-binding were O–H and C=O groups. We then studied the hypolipidemic effects of SRPE-3-Cr(Ⅲ) on type 2 diabetes mellitus (T2DM) induced by a high-fat, high-sucrose diet (HFSD). Decreased blood glucose content, body fat ratio, serum TG, TC, LDL-C, and increased serum HDL-C were observed after treatment with SRPE-3-Cr(Ⅲ). In addition, SRPE-3-Cr(Ⅲ) significantly reduced leptin, resistin, and TNF-α levels, and increased adiponectin contents relative to T2DM. Histopathology results also showed that SRPE-3-Cr(Ⅲ) could alleviate the HFSD-lesioned tissues. SRPE-3-Cr(Ⅲ) also improved lipid metabolism via a reduction in aspartate aminotransferase, alanine aminotransferase, fatty acid synthase, and acetyl-CoA carboxylase activities in the liver. SRPE-3-Cr(Ⅲ) at low doses exhibited better lipid-lowering activities, hence, could be considered to be a novel compound to treat hyperlipidemia and also act as an anti-diabetic agent.
Metabolic tuning of a stable microbial community in the surface oligotrophic Indian Ocean revealed by integrated meta-omics
Zhang-Xian Xie, Ke-Qiang Yan, Ling-Fen Kong, Ying-Bao Gai, Tao Jin, Yan-Bin He, Ya-Yu Wang, Feng Chen, Lin Lin, Zhi-Long Lin, Hong-Kai Xu, Zong-Ze Shao, Si-Qi Liu, Da-Zhi Wang
, Available online  , doi: 10.1007/s42995-021-00119-6
Abstract(284) HTML PDF Springerlink
Understanding the mechanisms, structuring microbial communities in oligotrophic ocean surface waters remains a major ecological endeavor. Functional redundancy and metabolic tuning are two mechanisms that have been proposed to shape microbial response to environmental forcing. However, little is known about their roles in the oligotrophic surface ocean due to less integrative characterization of community taxonomy and function. Here, we applied an integrated meta-omics-based approach, from genes to proteins, to investigate the microbial community of the oligotrophic northern Indian Ocean. Insignificant spatial variabilities of both genomic and proteomic compositions indicated a stable microbial community that was dominated by Prochlorococcus, Synechococcus, and SAR11. However, fine tuning of some metabolic functions that are mainly driven by salinity and temperature was observed. Intriguingly, a tuning divergence occurred between metabolic potential and activity in response to different environmental perturbations. Our results indicate that metabolic tuning is an important mechanism for sustaining the stability of microbial communities in oligotrophic oceans. In addition, integrated meta-omics provides a powerful tool to comprehensively understand microbial behavior and function in the ocean.
Metagenomic analysis reveals wide distribution of phototrophic bacteria in hydrothermal vents on the ultraslow-spreading Southwest Indian Ridge
Hong Chen, Deng Hui Li, Ai Jun Jiang, Xue Gong Li, Shi Jun Wu, Jian Wei Chen, Meng Jie Qu, Xiao Qing Qi, Jie Dai, Rui Zhao, Wei-Jia Zhang, Shan Shan Liu, Long-Fei Wu
, Available online  , doi: 10.1007/s42995-021-00121-y
Abstract(258) HTML PDF Springerlink
Deep-sea hydrothermal vents are known as chemosynthetic ecosystems. However, high temperature vents emit light that hypothetically can drive photosynthesis in this habitat. Metagenomic studies have sporadically reported the occurrence of phototrophic populations such as cyanobacteria in hydrothermal vents. To determine how geographically and taxonomically widespread phototrophs are in deep-sea hydrothermal vents, we collected samples from three niches in a hydrothermal vent on the Southwest Indian Ridge and carried out an integrated metagenomic analysis. We determined the typical community structures of microorganisms found in active venting fields and identified populations of known potential chlorophototrophs and retinalophototrophs. Complete chlorophyll biosynthetic pathways were identified in all samples. By contrast, proteorhodopsins were only found in active beehive smoker diffusers. Taxonomic groups possessing potential phototrophy dependent on semiconductors present in hydrothermal vents were also found in these samples. This systematic comparative metagenomic study reveals the widespread distribution of phototrophic bacteria in hydrothermal vent fields. Our results support the hypothesis that the ocean is a seed bank of diverse microorganisms. Geothermal vent light may provide energy and confer a competitive advantage on phototrophs to proliferate in hydrothermal vent ecosystems.
Contrasting patterns of bacterial communities in the rearing water and gut of Penaeus vannamei in response to exogenous glucose addition
Lei Huang, Haipeng Guo, Zidan Liu, Chen Chen, Kai Wang, Xiaolin Huang, Wei Chen, Yueyue Zhu, Mengchen Yan, Demin Zhang
, Available online  , doi: 10.1007/s42995-021-00124-9
Abstract(497) HTML PDF Springerlink
Supplementing exogenous carbon sources is a practical approach to improving shrimp health by manipulating the microbial communities of aquaculture systems. However, little is known about the microbiological processes and mechanisms of these systems. Here, the effects of glucose addition on shrimp growth performance and bacterial communities of the rearing water and the shrimp gut were investigated to address this knowledge gap. The results showed that glucose addition significantly improved the growth and survival of shrimp. Although the α-diversity indices of both bacterioplankton communities and gut microbiota were significantly decreased by adding glucose, both bacterial communities exhibited divergent response patterns to glucose addition. Glucose addition induced a dispersive bacterioplankton community but a more stable gut bacterial community. Bacterial taxa belonging to Ruegeria were significantly enriched by glucose in the guts, especially the operational taxonomic unit 2575 (OTU2575), which showed the highest relative importance to the survival rate and individual weight of shrimp, with the values of 43.8 and 40.6%, respectively. In addition, glucose addition increased the complexity of interspecies interactions within gut bacterial communities and the network nodes from Rhodobacteraceae accounted for higher proportions and linked more with the nodes from other taxa in the glucose addition group than that in control. These findings suggest that glucose addition may provide a more stable gut microbiota for shrimp by increasing the abundance of certain bacterial taxa, such as Ruegeria.
Linear polyketides produced by co-culture of Penicillium crustosum and Penicillium fellutanum
Guihong Yu, Peng Sun, Reyilamu Aierken, Chunxiao Sun, Zhenzhen Zhang, Qian Che, Guojian Zhang, Tianjiao Zhu, Qianqun Gu, Mingyu Li, Dehai Li
, Available online  , doi: 10.1007/s42995-021-00125-8
Abstract(206) HTML PDF Springerlink
Two new polyketides, penifellutins A (1) and B (2), possessing a 22 carbon linear skeleton, were isolated from a co-culture of the deep-sea-derived fungi Penicillium crustosum PRB-2 and Penicillium fellutanum HDN14-323. Meanwhile, two esterification products of 1, penifellutins C (3) and D (4), were obtained because compound 1 could be esterified spontaneously when stored in methanol. Their configurations were difficult to determine because of chiral central crowdedness, structural flexibility and instability. As such, we solved this issue by comprehensively using Mo2(OAc)4-based CD experiments, density functional theory calculation of 13C NMR, DP4 + probability analysis and many chemical reactions, including making acetonide derivative, Mosher's method, PGME method, etc. Compounds 1 and 2 show obvious inhibitory activity on the liver hyperplasia of zebrafish larvae at a concentration of 10 μmol/L, while 3 and 4 show no activity, indicating that two carboxyls in the structure are important active sites.
Metagenomes of polyamine-transforming bacterioplankton along a nearshore–open ocean transect
Xinxin Lu, Kai Wang, Xiaozhen Mou
, Available online  , doi: 10.1007/s42995-021-00114-x
Abstract(874) HTML PDF Springerlink
Short-chained aliphatic polyamines (PAs) have recently been recognized as an important carbon, nitrogen, and/or energy source for marine bacterioplankton. To study the genes and taxa involved in the transformations of different PA compounds and their potential variations among marine systems, we collected surface bacterioplankton from nearshore, offshore, and open ocean stations in the Gulf of Mexico and examined their metagenomic responses to additions of single PA model compounds (putrescine, spermidine, or spermine). Genes affiliated with PA uptake and all three known PA degradation pathways, i.e., transamination, γ-glutamylation, and spermidine cleavage, were significantly enriched in most PA-treated metagenomes. In addition, identified PA-transforming taxa were mostly the alpha and gamma classes of Proteobacteria, with less important contributions from members of Betaproteobacteria, Actinobacteria, Bacteroidetes, Cyanobacteria, Firmicutes, and Planctomycetes. These findings suggest that PA transformations are ubiquitous, have diverse pathways, and are carried out by a broad range of the bacterioplankton taxa in the Gulf of Mexico. Identified PA-transforming bacterial genes and taxa were different among nearshore, offshore, and open ocean sites, but were little different among individual compound-amended metagenomes at any specific site. These observations further indicate that PA-transforming taxa and genes are site-specific and with high similarities among PA compounds.
Application of enzymes as a feed additive in aquaculture
Qingping Liang, Mingxue Yuan, Liping Xu, Elia Lio, Fang Zhang, Haijin Mou, Francesco Secundo
, Available online  , doi: 10.1007/s42995-022-00128-z
Abstract(52) HTML PDF Springerlink
Modern aquaculture must be sustainable in terms of energy consumption, raw materials used, and environmental impact, so alternatives are needed to replace fish feed with other raw materials. Enzyme use in the agri-food industry is based on their efficiency, safety, and protection of the environment, which aligns with the requirements of a resource-saving production system. Enzyme supplementation in fish feed can improve digestibility and absorption of both plant- and animal-derived ingredients, increasing the growth parameters of aquacultural animals. Herein we summarized the recent literature that reported the use of digestive enzymes (amylases, lipases, proteases, cellulases, and hemicellulases) and non-digestive enzymes (phytases, glucose oxidase, and lysozyme) in fish feed. In addition, we analyzed how critical steps of the pelleting process, including microencapsulation and immobilization, can interfere with enzyme activity in the final fish feed product.
The role of bacterial signaling networks in antibiotics response and resistance regulation
Yuying Li, Tao Feng, Yan Wang
, Available online  , doi: 10.1007/s42995-022-00126-1
Abstract(59) HTML PDF Springerlink
Excessive use of antibiotics poses a threat to public health and the environment. In ecosystems, such as the marine environment, antibiotic contamination has led to an increase in bacterial resistance. Therefore, the study of bacterial response to antibiotics and the regulation of resistance formation have become an important research field. Traditionally, the processes related to antibiotic responses and resistance regulation have mainly included the activation of efflux pumps, mutation of antibiotic targets, production of biofilms, and production of inactivated or passivation enzymes. In recent years, studies have shown that bacterial signaling networks can affect antibiotic responses and resistance regulation. Signaling systems mostly alter resistance by regulating biofilms, efflux pumps, and mobile genetic elements. Here we provide an overview of how bacterial intraspecific and interspecific signaling networks affect the response to environmental antibiotics. In doing so, this review provides theoretical support for inhibiting bacterial antibiotic resistance and alleviating health and ecological problems caused by antibiotic contamination.