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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
Expanding our understanding of marine viral diversity through metagenomic analyses of biofilms
Wei Ding, Ruojun Wang, Zhicong Liang, Rui Zhang, Pei-Yuan Qian, Weipeng Zhang
, Available online  , doi: 10.1007/s42995-020-00078-4
Abstract(1133) HTML PDF Springerlink
Recent metagenomics surveys have provided insights into the marine virosphere. However, these surveys have focused solely on viruses in seawater, neglecting those associated with biofilms. By analyzing 1.75 terabases of biofilm metagenomic data, 3974 viral sequences were identified from eight locations around the world. Over 90% of these viral sequences were not found in previously reported datasets. Comparisons between biofilm and seawater metagenomes identified viruses that are endemic to the biofilm niche. Analysis of viral sequences integrated within biofilm-derived microbial genomes revealed potential functional genes for trimeric autotransporter adhesin and polysaccharide metabolism, which may contribute to biofilm formation by the bacterial hosts. However, more than 70% of the genes could not be annotated. These findings show marine biofilms to be a reservoir of novel viruses and have enhanced our understanding of natural virus-bacteria ecosystems.
High chromosomal evolutionary dynamics in sleeper gobies (Eleotridae) and notes on disruptive biological factors in Gobiiformes karyotypes (Osteichthyes, Teleostei)
Simião Alefe Soares da Silva, Paulo Augusto de Lima-Filho, Clóvis Coutinho da Motta-Neto, Gideão Wagner Werneck Félix da Costa, Marcelo de Bello Cioffi, Luiz Antônio Carlos Bertollo, Wagner Franco Molina
, Available online  , doi: 10.1007/s42995-020-00084-6
Abstract(688) HTML PDF Springerlink
The order Gobiiformes is made up of more than 2200 species, representing one of the most diverse groups among teleost fishes. The biological causes for the tachytelic karyotype evolution of the gobies have not yet been fully studied. Here we expanded cytogenetic data for the Eleotridae family, analyzing the neotropical species Dormitator maculatus, Eleotris pisonis, Erotelis smaragdus, and Guavina guavina. In addition, a meta-analytical approach was followed for elucidating the karyotype diversification versus biological aspects (habitat and egg type) of the Gobiiformes. The species E. smaragdus and E. pisonis present 2n = 46 acrocentric chromosomes (NF = 46), D. maculatus 2n = 46 (36sm + 4st + 6a; NF = 86), and G. guavina, the most divergent karyotype, with 2n = 52 acrocentric chromosomes (NF = 52). Besides numeric and structural diversification in the karyotypes, the mapping of rDNAs and microsatellites also showed noticeable numerical and positional variation, supporting the high chromosomal evolutionary dynamism of these species. In Gobiiformes, karyotype patterns which are more divergent from the basal karyotype (2n = 46a) are associated with characteristics less effective to dispersion, such as the benthic habit. These adaptive characteristics, connected with the organization of the repetitive DNA content in the chromosomes, likely play a synergistic role in the remarkable karyotype diversification of this group.
A new hypotrich ciliate, Oxytricha xianica sp.nov., with notes on the morphology and phylogeny of a Chinese population of Oxytricha auripunctata Blatterer & Foissner, 1988(Ciliophora, Oxytrichidae)
Jingyi Wang, Tengteng Zhang, Fengchao Li, Alan Warren, Yanbo Li, Chen Shao
, Available online  , doi: 10.1007/s42995-020-00089-1
Abstract(714) HTML PDF Springerlink
The morphology and infraciliature of the new hypotrichous ciliate, Oxytricha xianica sp.nov., and a Chinese population of Oxytricha auripunctata Blatterer & Foissner, 1988, are investigated using live observation and protargol staining.Oxytricha xianica defined by the body size 85-130 μm × 30-50 μm in vivo, the typical oxytrichid 18 frontoventral-transverse cirri, cortical granules absent, undulating membranes reduced or absent, three caudal cirri, dorsal kineties in Oxytricha pattern, and two ellipsoidal macronuclear nodules.The Chinese population of O.auripunctata differs slightly from other populations in the arrangement and color of cortical granules and position of anterior end of dorsal kinety 4.Phylogenetic analyses based on SSU-rDNA sequences support the assertion that O.auripunctata belongs to Oxytricha and Oxytrichidae.
Reproductive biology of female sawcheek scorpionfish, Brachypterois serrulata (Richardson, 1846) (Teleostei; Scorpaenidae) from Visakhapatnam Coast, India
Muddula Krishna Naranji, Govinda Rao Velamala, Kandula Sujatha
, Available online  , doi: 10.1007/s42995-020-00083-7
Abstract(879) HTML PDF Springerlink
We examined the reproductive biology of sawcheek scorpionfish, Brachypterois serrulata, collected from Visakhapatnam fish landing center (fishing area covered 16.98°-20.20°N, 82.19°-86.53°E). We studied the annual reproductive cycle, fecundity, size at first maturity, mode of spawning with periodical changes and histological preparations. Size distribution and size at sexual maturity were calculated as 108 mm TL for females. The mean gonado somatic index values of female increased rapidly from January to December, and reached its peak during January and February. The fecundity of the fish species is determined by the size and weight of the individuals. The fecundity varied from 1896 to 20, 488, with an average of 5721.90 ova.
Growth, serum biochemical parameters, salinity tolerance and antioxidant enzyme activity of rainbow trout (Oncorhynchus mykiss) in response to dietary taurine levels
Ming Huang, Xiaogang Yang, Yangen Zhou, Jian Ge, D. Allen Davis, Yunwei Dong, Qinfeng Gao, Shuanglin Dong
, Available online  , doi: 10.1007/s42995-020-00088-2
Abstract(727) HTML PDF Springerlink
This study evaluated the effect of dietary taurine levels on growth, serum biochemical parameters, salinity adaptability, and antioxidant activity of rainbow trout (Oncorhynchus mykiss). Four diets were formulated with taurine supplements at 0, 0.5, 1, and 2% w/v (abbreviated as T0, T0.5, T1, and T2, respectively). Rainbow trouts (initial weight of 80.09 ± 4.72 g) were stocked in tanks (180 L capacity), and were fed these diets for six weeks and subsequently underwent salinity acclimation. Physiological indicators were determined before salinity acclimation at 1, 4, 7, and 14 days afterwards. Results showed that there were no significant differences in growth performance (final mean weight ranged from 182.35 g to 198.48 g; percent weight gain was between 127.68% and 147.92%) of rainbow trout in freshwater stage, but dietary taurine supplement significantly increased serum-free taurine content. After entering seawater, the Na+-K+-ATPase activity of T2 group returned to its freshwater levels, and the serum cortisol content was significantly higher than T0 and T0.5 groups. At the end of this experiment, the liver superoxide dismutase activity in the T0 and T0.5 groups was significantly lower than in the T1 and T2 groups, and the liver catalase in the T0 group was the lowest whereas that in the T2 group was the highest. Muscle malondialdehyde content was the highest in the T0 group, and the lowest in the T2 group. Based on the results of this study, supplement of dietary taurine (0.5-2%) enhanced the salinity tolerance in rainbow trout, which increased with the higher taurine concentration.
Visual detection of tropomyosin, a major shrimp allergenic protein using gold nanoparticles (AuNPs)-assisted colorimetric aptasensor
Tushar Ramesh Pavase, Hong Lin, Maqsood Ahmed Soomro, Hongwei Zheng, Xiaxia Li, Kexin Wang, Zhenxing Li
, Available online  , doi: 10.1007/s42995-020-00085-5
Abstract(414) HTML PDF Springerlink
A gold nanoparticle-based label-free colorimetric assay was developed to detect the shrimp allergenic protein tropomyosin (TM), an important biomarker responsible for severe clinical reactivity to shellfish. In a gold nanoparticles (AuNPs)-tropomyosin-binding aptamer (TMBA) complex, the aptamer adsorbs onto the surface of AuNPs and dissociates in the presence of TM. In addition, AuNPs tend to aggregate in the presence of ionic salt, revealing a color change (i.e., wine-red to purple/blue) with a shift in the maximum absorption peak from 520 nm. In the presence of specific binding TM, the aptamer folds into a tertiary structure where it more efficiently stabilizes AuNPs toward the salt-induced aggregation with a hypsochromic shift in the absorption spectra compared to the stabilized AuNPs by aptamer alone. Based on the aggregation and sensitive spectral transformation principle, the AuNPs-based colorimetric aptasensor was successfully applied to detect TM with a range of 10-200 nmol/L and a low detection limit of 40 nmol/L in water samples. The reliability, selectivity, and sensitivity of the aptasensor was then tested with food samples spiked with TM. The observed detection limit was as low as 70 nmol/L in shrimp, 90 nmol/L in tofu, and 80 nmol/L in eggs, respectively. We anticipate the proposed AuNPs-based colorimetric aptasensor assay possesses a high potential for the easy and efficient visual colorimetric detection of TM.
Hepatic cecum: a key integrator of immunity in amphioxus
Baozhen Qu, Shicui Zhang, Zengyu Ma, Zhan Gao
, Available online  , doi: 10.1007/s42995-020-00080-w
Abstract(737) HTML PDF Springerlink
The vertebrate liver is regarded as an organ essential to the regulation of immunity and inflammation as well as being central to the metabolism of nutrients. Here, we discuss the functions that the hepatic cecum of amphioxus plays in the regulation of immunity and inflammation, and the molecular basis of this. It is apparent that the hepatic cecum performs important roles in the immunity of amphioxus including immune surveillance, clearance of pathogens and acute phase response. Therefore, the hepatic cecum, like the vertebrate liver, is an organ functioning as a key integrator of immunity in amphioxus.
The parasitic dinoflagellate Hematodinium infects marine crustaceans
Caiwen Li, Meng Li, Qian Huang
, Available online  , doi: 10.1007/s42995-020-00061-z
Abstract(464) HTML PDF Springerlink
Hematodinium is a type of parasitic dinoflagellate that infects marine crustaceans globally. The parasite lives mainly in the hemolymph or hemocoels of affected hosts, and results in mortalities due to malfunction or loss of functions of major organs. In recent years, the parasite had developed into an emerging epidemic pathogen not only affecting wild populations of economically valuable marine crustaceans in western countries but also the sustainable yield of aquaculture of major crabs in China. The epidemics of the parasitic diseases expanded recently in the coastal waters of China, and caused frequent outbreaks in aquaculture of major crab species, especially Portunus trituberculatus and Scylla paramamosain. In addition, the pathogen infected two species of co-cultured shrimps and multiple cohabitating wild crabs, implying it is a significant threat to the sustainable culture of commercially valuable marine crustaceans. In particular, the polyculture system that is widely used along the coast of China may facilitate the spread and transmission of the pathogen. Thus, to provide a better understanding of the biological and ecological characteristics of the parasitic dinoflagellate and highlight important directions for future research, we have reviewed the current knowledge on the taxonomy, life cycle, pathogenesis, transmission and epidemiology of Hematodinium spp. Moreover, ecological countermeasures have been proposed for the prevention and control of the emerging infectious disease.
Co-culture: stimulate the metabolic potential and explore the molecular diversity of natural products from microorganisms
Xiao-Yue Peng, Jin-Tao Wu, Chang-Lun Shao, Zhi-Yong Li, Min Chen, Chang-Yun Wang
, Available online  , doi: 10.1007/s42995-020-00077-5
Abstract(166) HTML PDF Springerlink
Microbial secondary metabolites have long been considered as potential sources of lead compounds for medicinal use due to their rich chemical diversity and extensive biological activities. However, many biosynthetic gene clusters remain silent under traditional laboratory culture conditions, resulting in repeated isolation of a large number of known compounds. The co-culture strategy simulates the complex ecological environment of microbial life by using an ecology-driven method to activate silent gene clusters of microorganisms and tap their metabolic potential to obtain novel bioactive secondary metabolites. In this review, representative studies from 2017 to 2020 on the discovery of novel bioactive natural products from co-cultured microorganisms are summarized. A series of natural products with diverse and novel structures have been discovered successfully by co-culture strategies, including fungus-fungus, fungus-bacterium, and bacterium-bacterium co-culture approaches. These novel compounds exhibited various bioactivities including extensive antimicrobial activities and potential cytotoxic activities, especially when it came to disparate marine-derived species and cross-species of marine strains and terrestrial strains. It could be concluded that co-culture can be an effective strategy to tap the metabolic potential of microorganisms, particularly for marine-derived species, thus providing diverse molecules for the discovery of lead compounds and drug candidates.