A Gram-stain-negative, rod-shaped bacterial strain, JC4T, was isolated from a freshwater sample and determined the taxonomic position. Initial identification based on 16S rRNA gene sequences revealed that strain JC4T is affiliated to the genus Mucilaginibacter with a sequence similarity of 97.97% to Mucilaginibacter rigui WPCB133T. The average nucleotide identity and digital DNA-DNA hybridization values between strain JC4T and Mucilaginibacter species were estimated below 80.92% and 23.9%, respectively. Strain JC4T contained summed feature 3 (C16:1 ω7c and/or C16:1 ω6c) and iso-C15:0 as predominant cellular fatty acids. The dominant polar lipids were identified as phosphatidylethanolamine, one unidentified aminophospholipid, one unidentified phospholipid, and two unidentified lipids. The respiratory quinone was MK-7. The genomic DNA G+C content of strain JC4T was determined to be 42.44%. The above polyphasic evidences support that strain JC4T represents a novel species of the genus Mucilaginibacter, for which the name Mucilaginibacter aquariorum sp. nov. is proposed. The type strain is JC4T (= KCTC 92230T = LMG 32715T).

Freshwater lakes and ponds present an ecological interface between humans and a variety of host organisms. They are a habitat for the larval stage of many insects and may serve as a medium for intraspecies and interspecies transmission of viruses such as avian influenza A virus. Furthermore, freshwater bodies are already known repositories for disease-causing viruses such as Norwalk Virus, Coxsackievirus, Echovirus, and Adenovirus. While RNA virus populations have been studied in marine environments, to this date there has been very limited analysis of the viral community in freshwater. Here we present a survey of RNA viruses in Lake Needwood, a freshwater lake in Maryland, USA. Our results indicate that just as in studies of other aquatic environments, the majority of nucleic acid sequences recovered did not show any significant similarity to known sequences. The remaining sequences are mainly from viral types with significant similarity to approximately 30 viral families. We speculate that these novel viruses may infect a variety of hosts including plants, insects, fish, domestic animals and humans. Among these viruses we have discovered a previously unknown dsRNA virus closely related to Banna Virus which is responsible for a febrile illness and is endemic to Southeast Asia. Moreover we found multiple viral sequences distantly related to Israeli Acute Paralysis virus which has been implicated in honeybee colony collapse disorder. Our data suggests that due to their direct contact with humans, domestic and wild animals, freshwater ecosystems might serve as repositories of a wide range of viruses (both pathogenic and non-pathogenic) and possibly be involved in the spread of emerging and pandemic diseases.

This work investigates the role of hydrogen sulfide (H2S) in the browning and regulating the antioxidant defensive system in fresh-cut Chinese water chestnuts. The samples were fumigated with 0, 10, and 15 μl L-1 of H2S and stored at 10°C for 8 days. The results indicated that the H2S treatment significantly inhibited the browning of fresh-cut Chinese water chestnuts, reduced superoxide anion ( O 2 · - ) production rate and H2O2 content accumulation, promoted the increase of total phenol content, and enhanced activities of catalase (CAT), superoxide dismutase (SOD), ascorbate peroxidase (APX), and glutathione reductase (GR) (P < 0.05). On the other hand, phenylalanine ammonia lyase (PAL), polyphenol oxidase (PPO), and peroxidase (POD) activities remained at a low level in the H2S treatment (P < 0.05). This result suggested that H2S treatment might be a promising approach to inhibit browning and prolong the shelf life by enhancing oxidation resistance and inhibiting browning enzyme activity of fresh-cut Chinese water chestnuts during storage. Among them, the 15 μl L-1 H2S treatment had the best effect on fresh-cut Chinese water chestnuts.

Chromium is considered as one of the most common ubiquitous pollutants in the aquatic environment, but the pure metallic form is absent naturally. There are three oxidation states in case of Chromium viz., Cr (II), Cr (III), Cr (VI). Among which Cr (II) is most unstable. Cr (III) and Cr (VI) are the stable oxidation state of Chromium in the environment. Being one of the commonly used metals Chromium and its particulates enter the aquatic medium through effluents discharged from different industries like textiles, tanneries, electroplating workshops, ore mining, dyeing, printing-photographic and medical industries. Among these, hexavalent chromium is considered as the most toxic form because it readily passes cellular membranes and then reduced to trivalent form. This trivalent chromium combines with several macromolecules including genetic material inside the cytosol, and is ultimately exposes the toxic and mutagenic alterations due of chromium toxicity. Chromium is taken up either through gastrointestinal tract or respiratory tract. The amount varies depending upon the medium and the form of chromium. In this review, an attempt has been made to accumulate the mammoth available data regarding impact of chromium on fresh water fishes into a systematic representation. The main objective of the review is to provide a future guideline for the scientific community and public officials involved in health risk assessment and management ensuring a better environmental condition for human health.

Macrobioerosion is a common process in marine ecosystems. Many types of rock-boring organisms break down hard substrates, particularly carbonate rocks and calcareous structures such as dead corals and shells. In paleontology, the presence of rocks with boreholes and fossil macroboring assemblage members is one of the primary diagnostic features of shallow marine paleo-environments. Here we describe a silicate rock-boring organism and an associated community in submerged siltstone rock outcrops in Kaladan River, Myanmar. The rock-boring mussel Lignopholas fluminalis is a close relative of the marine piddocks, and its borings belong to the ichnospecies Gastrochaenolites anauchen. The neotectonic uplift of the area leading to gradual decrease of the sea level with subsequent shift from estuarine to freshwater environment was the most likely driver for the origin of this community. Our findings highlight that rocks with macroborings are not an exclusive indicator of marine paleo-ecosystems, but may also reflect freshwater habitats.

Sugarcane bagasse is a vast lignocellulosic byproduct generated in the industry with ~50% humidity (1 kg dry matter associated with 1 kg water). Although the presence of water brings deleterious consequences for combustion, storage and sugar extraction, the location of water in fresh bagasse remains unknown. In this work, we use synchrotron X-ray microtomography for non-invasive 3D imaging of fresh bagasse particles, which allows the visualization of intraparticle water. The sclerified fiber cells in the sheaths surrounding xylem vessels are often found full of water. We suggest this can be juice preserved from the native stalks as many sclerified fibers seem to keep their structural integrity despite the mechanical action during sugarcane crushing. The microtomograms of fresh bagasse also shows mineral particles adhered to biomass surfaces, with adhesion presumably favored by the presence of water. In summary, this work unveils the location of water in fresh bagasse, solving an old mystery of sugarcane technology.

The energy shortage and clean water scarcity are two key challenges for global sustainable development. Near half of the total global water withdrawals is consumed by power generation plants while water desalination consumes lots of electricity. Here, we demonstrate a photovoltaics-membrane distillation (PV-MD) device that can stably produce clean water (>1.64 kg·m-2·h-1) from seawater while simultaneously having uncompromised electricity generation performance (>11%) under one Sun irradiation. Its high clean water production rate is realized by constructing multi stage membrane distillation (MSMD) device at the backside of the solar cell to recycle the latent heat of water vapor condensation in each distillation stage. This composite device can significantly reduce capital investment costs by sharing the same land and the same mounting system and thus represents a potential possibility to transform an electricity power plant from otherwise a water consumer to a fresh water producer.

The genus Streptomyces under phylum actinobacteria has been recognized as a prolific source for the production of bioactive secondary metabolites. An actinobacterial strain designated as DST103 isolated from a wetland fresh water sediment of Tamdil Lake, Mizoram, Northeast, India was identified as Streptomyces cyaneofuscatus (KY287599) using 16SrRNA gene sequencing which shares 99.87% sequence similarity with Streptomyces cyaneofuscatus NRRL B-2570 T . The strain showed broad spectrum antimicrobial activities against Gram negative bacteria (Escherichia coli MTCC 739 and Pseudomonas aeruginosa MTCC 2453), Gram positive bacteria (Micrococcus luteus NCIM 2170 and Staphylococcus aureus MTCC 96) and yeast pathogen Candida albicans MTCC 3017). The methanolic extract of the strain DST103 exhibited highest antimicrobial activity against E. coli (IC50 = 2.10 μg/mL) and minimum activity against S. aureus (IC50 = 43.63 μg/mL). Five antibiotics [trimethoprim (18 μg/g), fluconazole (6 μg/g), ketoconazole (18 μg/g), nalidixic acid (135 μg/g), and rifampicin (56 μg/g)] were detected and quantified using ultra-performance liquid chromatography (UPLC-ESI-MS/MS). Further, biosynthetic potential genes [polyketide synthases type II, non-ribosomal peptide synthetases, and aminodeoxyisochorismate synthase (phzE)] were also detected in strain DST103 which may possibly be responsible for the production of antimicrobial compounds. Additionally, gas chromatography-mass spectrometry analysis showed the presence of four volatile compounds which might be responsible for their diverse biological activity. The present study revealed the presence of bioactive compounds in strain DST103, which may be a promising resource for the discovery of novel bioactive metabolites against wide range of pathogens.

Pollutants in aquatic food are a major global concern for food safety and are a challenge to both national and international regulatory bodies. In the present work, we have reviewed available data on the concentrations of polycyclic aromatic hydrocarbons (PAH), persistent organic pollutants, metals, and microplastics in freshwater and marine fish in Nigeria with reference to international maximum levels for contaminants in food and the potential risk to human health. While most of the contaminant levels reported for fish do not imply any health issues, iron and lead may represent potentially toxic levels in fish from specific areas. Studies on PAHs in marine fish are scarce in Nigeria, and the main focus is on the environmental pollution caused by PAHs rather than on their presence in food. The findings suggest that the consumption of smoked Ethmalosa fimbriata poses a higher potential carcinogenic risk than the other fish species that were investigated. Most of the other studies on PAHs in smoked fish are focused on the smoking method, and little information is available on the initial level of PAHs prior to the smoking process. Metal contamination in fish appeared to be affected by mineral deposits in the environment and industrial effluents. In general, heavy metal levels in fish are below the maximum levels, while there is limited data available on POPs of relevance to food safety in fish from Nigeria, particularly in terms of dioxins, brominated flame retardants, and fluorinated compounds. Furthermore, there is currently limited information on the levels of microplastics in fish from Nigerian waters. This work revealed the need for a more systematic sampling strategy for fish in order to identify the most vulnerable species, the hot spots of contaminants, and applicable food safety control measures for fish produced and consumed in Nigeria.

Due to its extreme salinity and high Mg concentration the Dead Sea is characterized by a very low density of cells most of which are Archaea. We discovered several underwater fresh to brackish water springs in the Dead Sea harboring dense microbial communities. We provide the first characterization of these communities, discuss their possible origin, hydrochemical environment, energetic resources and the putative biogeochemical pathways they are mediating. Pyrosequencing of the 16S rRNA gene and community fingerprinting methods showed that the spring community originates from the Dead Sea sediments and not from the aquifer. Furthermore, it suggested that there is a dense Archaeal community in the shoreline pore water of the lake. Sequences of bacterial sulfate reducers, nitrifiers iron oxidizers and iron reducers were identified as well. Analysis of white and green biofilms suggested that sulfide oxidation through chemolitotrophy and phototrophy is highly significant. Hyperspectral analysis showed a tight association between abundant green sulfur bacteria and cyanobacteria in the green biofilms. Together, our findings show that the Dead Sea floor harbors diverse microbial communities, part of which is not known from other hypersaline environments. Analysis of the water's chemistry shows evidence of microbial activity along the path and suggests that the springs supply nitrogen, phosphorus and organic matter to the microbial communities in the Dead Sea. The underwater springs are a newly recognized water source for the Dead Sea. Their input of microorganisms and nutrients needs to be considered in the assessment of possible impact of dilution events of the lake surface waters, such as those that will occur in the future due to the intended establishment of the Red Sea-Dead Sea water conduit.

N-Acyl homoserine lactone (AHL) serves as signaling molecule for quorum sensing (QS) in Gram-negative bacteria to regulate various physiological activities including pathogenicity. With the aim of isolating freshwater-borne bacteria that can cause outbreak of disease in plants and portrayed QS properties, environmental water sampling was conducted. Here we report the preliminary screening of AHL production using Chromobacterium violaceum CV026 and Escherichia coli [pSB401] as AHL biosensors. The 16S rDNA gene sequence of isolate M009 showed the highest sequence similarity to Pantoea stewartii S9-116, which is a plant pathogen. The isolated Pantoea sp. was confirmed to produce N-3-oxohexanoyl-L-HSL (3-oxo-C6-HSL) through analysis of high resolution mass tandem mass spectrometry.

Rapid adaptation to novel environments may drive changes in genomic regions through natural selection. However, the genetic architecture underlying these adaptive changes is still poorly understood. Using population genomic approaches, we investigated the genomic architecture that underlies rapid parallel adaptation of Coilia nasus to fresh water by comparing four freshwater-resident populations with their ancestral anadromous population. Linkage disequilibrium network analysis and population genetic analyses revealed two putative large chromosome inversions on LG6 and LG22, which were enriched for outlier loci and exhibited parallel association with freshwater adaptation. Drastic frequency shifts and elevated genetic differentiation were observed for the two chromosome inversions among populations, suggesting that both inversions would undergo divergent selection between anadromous and resident ecotypes. Enrichment analysis of genes within chromosome inversions showed significant enrichment of genes involved in metabolic process, immunoregulation, growth, maturation, osmoregulation, and so forth, which probably underlay differences in morphology, physiology and behavior between the anadromous and freshwater-resident forms. The availability of beneficial standing genetic variation, large optimum shift between marine and freshwater habitats, and high efficiency of selection with large population size could lead to the observed rapid parallel adaptive genomic change. We propose that chromosomal inversions might have played an important role during the evolution of rapid parallel ecological divergence in the face of environmental heterogeneity in C. nasus. Our study provides insights into the genomic basis of rapid adaptation of complex traits in novel habitats and highlights the importance of structural genomic variants in analyses of ecological adaptation.

To understand the physiological and molecular endocrine changes that occur in response to a salinity challenge, we transferred rainbow trout from fresh water to an ion-poor or 24‰ saltwater treatment for 14 days. An increase in gill Na(+), K(+)-ATPase (NKA) activity in salt water was associated with higher mRNA expression for the NKA α1b subunit. In contrast, there was little change in gill NKA activity following transfer to ion-poor water, but the mRNA expression of NKA α1a was significantly elevated. Endocrine signals were assessed by measuring plasma cortisol concentrations and by quantifying changes in mRNA extracted from the gill for glucocorticoid receptors 1 and 2 (GR1 and GR2), mineralocorticoid receptor (MR), growth hormone receptor (GHR1), and prolactin receptor (PrlR). Cortisol increased after transfer to ion-poor and salt water, but both GR and MR mRNA in the gill showed little change. PrlR mRNA was significantly higher when fish were transferred to the ion-poor water and GHR1 mRNA was elevated during the saltwater challenge. This study demonstrated an increase in gill PrlR mRNA that parallels the changes in gill NKA α1a when rainbow trout were transferred to a lower salinity level. Furthermore, the increase in gill GHR1 mRNA supports the importance of GH for seawater acclimation as there is a corresponding increase in the expression of gill NKA α1b, the saltwater isoform. GH and Prl, therefore, may differentially determine the function of cortisol in both fresh- and saltwater ionoregulation.

Magnetotactic bacteria (MTB) are of considerable interest because of their importance in the manufacture of various bioinspired materials. In order to find out the status of magnetotactic bacteria at three different sediment in Czech Republic, samples collected from both standing and running freshwaters were subjected to molecular diversity analysis by using 16S rRNA gene approach. Total community DNA from sediment sample was isolated and used for PCR, cloning and sequence analysis. Of the 24 analyzed sequences, six clones are closely related to Magnetobacterium sp. affiliated with the Nitrospira phylum which showed the dominance of Magnetobacterium phylotypes in the sample. This study will provide useful insight about the community structure of MTB in this particular geographical region. However more detailed and specific studies are warranted in order to properly assess the community structure of MTB's in fresh water sediments.

Interest in novel ligninolytic bacteria has remained topical due to, in part, the maneuverability of the bacterial genome. Conversely, the fungal genome lacks the dexterity for similar maneuverability thus, posing challenges in the fungal enzyme yield optimization process. Some impact of this situation includes the inability to commercialize the bio-catalytic process of lignin degradation by fungi. Consequently, this study assessed some fresh water bacteria isolates for ligninolytic and peroxidase properties through the utilization and degradation of model lignin compounds (guaiacol and veratryl alcohol) and the decolourization of selected ligninolytic indicator dyes; Azure B (AZB), Remazol Brilliant Blue R (RBBR) and Congo Red (CR). Bacterial strains with appreciable ligninolytic and peroxidase production potentials were identified through 16S rDNA sequence analysis and the nucleotide sequences deposited in the GenBank. About 5 isolates were positive for the degradation of both guaiacol (GA) and veratryl alcohol (VA) thus, accounting for about 17% of the test isolates. Similarly, AZB, RBBR and CR were respectively decolorized by 3, 2 and 5 bacterial strains thus, accounting for 10%, 7% and 17% of the test isolates. Two of the test bacterial strains were able to decolourize AZB, RBBR and CR respectively and these bacterial strains were identified as Raoultella ornithinolytica OKOH-1 and Ensifer adhaerens NWODO-2 with respective accession numbers as KX640917 and KX640918. Upon quantitation of the peroxidase activities; 5250 ± 0.00 U/L was recorded against Raoultella ornithinolytica OKOH-1 and 5833 ± 0.00 U/L against Ensifer adhaerens NWODO-2. The ligninolytic and dye decolourization properties of Raoultella ornithinolytica OKOH-1 and Ensifer adhaerens NWODO-2 marks for novelty particularly, as dyes with arene substituents were decolourized. Consequently, the potentials for the industrial applicability of these test bacterial strains abound as there is a dearth of information on organisms with such potentials.

Phytonutrients and pigments present in cyanobacteria act as antioxidants, which facilitate the formation of body's defense mechanism against free radical damage to cells. The aim of this investigation was to study the total phenolic content (TPC), total flavonoid content (TFC), antioxidant activity, phycobiliproteins (PBPs), and active compounds in four cyanobacterial species, that is, Oscillatoria sp., Lyngbya sp., Microcystis sp., and Spirulina sp. isolated from fresh water bodies of Sri Lanka. In this study, Lyngbya sp., showed highest TPC (5.02 ± 0.20 mg/g), TFC (664.07 ± 19.76 mg/g), and total PBPs (127.01 mg/g) value. The ferric reducing antioxidant power (FRAP) was recorded highest in Oscillatoria sp. (39.63 ± 7.02), whereas the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity was also reported the highest in Oscillatoria sp. (465.31 ± 25.76) followed by Lyngbya sp. (248.39 ± 11.97). In FTIR spectroscopy, Lyngbya sp. does not show any N-H stretching band which is ultimately responsible for the inhibition of antioxidant activity. The study revealed that Lyngbya sp. and Oscillatoria sp. can be an excellent source for food, pharmaceutical, and other industrial uses.

Gram-negative bacilli of the genus Aeromonas are primarily inhabitants of the aquatic environment. Humans acquire this organism from a wide range of food and water sources as well as during aquatic recreational activities. In the present study, the diversity and distribution of Aeromonas species from freshwater lakes in Malaysia was investigated using glycerophospholipid-cholesterol acyltransferase (GCAT) and RNA polymerase sigma-factor (rpoD) genes for speciation. A total of 122 possible Aeromonas strains were isolated and confirmed to genus level using the API20E system. The clonality of the isolates was investigated using ERIC-PCR and 20 duplicate isolates were excluded from the study. The specific GCAT-PCR identified all isolates as belonging to the genus Aeromonas, in agreement with the biochemical identification. A phylogenetic tree was constructed using the rpoD gene sequence and all 102 isolates were identified as: A. veronii 43%, A. jandaei 37%, A. hydrophila 6%, A. caviae 4%, A. salmonicida 2%, A. media 2%, A. allosaccharophila 1%, A. dhakensis 1% and Aeromonas spp. 4%. Twelve virulence genes were present in the following proportions--exu 96%, ser 93%, aer 87%, fla 83%, enolase 70%, ela 62%, act 54%, aexT 33%, lip 16%, dam 16%, alt 8% and ast 4%, and at least 2 of these genes were present in all 102 strains. The ascV, aexU and hlyA genes were not detected among the isolates. A. hydrophila was the main species containing virulence genes alt and ast either present alone or in combination. It is possible that different mechanisms may be used by each genospecies to demonstrate virulence. In summary, with the use of GCAT and rpoD genes, unambiguous identification of Aeromonas species is possible and provides valuable data on the phylogenetic diversity of the organism.

Fish gills represent a complex organ composed of several cell types that perform multiple physiological functions. Among these cells, ionocytes are implicated in the maintenance of ion homeostasis. However, because the ionocyte represents only a small percent of whole gill tissue, its specific transcriptome can be overlooked among the numerous cell types included in the gill. The objective of this study is to better understand ionocyte functions by comparing the RNA expression of this cell type in freshwater and seawater acclimated rainbow trout. To realize this objective, ionocytes were captured from gill cryosections using laser capture microdissection after immunohistochemistry. Then, transcriptome analyses were performed on an Agilent trout oligonucleotide microarray. Gene expression analysis identified 108 unique annotated genes differentially expressed between freshwater and seawater ionocytes, with a fold change higher than 3. Most of these genes were up-regulated in freshwater cells. Interestingly, several genes implicated in ion transport, extracellular matrix and structural cellular proteins appeared up-regulated in freshwater ionocytes. Among them, several ion transporters, such as CIC2, SLC26A6, and NBC, were validated by qPCR and/or in situ hybridization. The latter technique allowed us to localize the transcripts of these ion transporters in only ionocytes and more particularly in the freshwater cells. Genes involved in metabolism and also several genes implicated in transcriptional regulation, cell signaling and the cell cycle were also enhanced in freshwater ionocytes. In conclusion, laser capture microdissection combined with microarray analysis allowed for the determination of the transcriptional signature of scarce cells in fish gills, such as ionocytes, and aided characterization of the transcriptome of these cells in freshwater and seawater acclimated trout.

The common use of chemical elements by man has been contributing to their extraction for centuries. As a consequence, they have been directly or indirectly introduced into the biogeochemical cycle. In the framework of many conventions, mining and processing of elements are currently subject to many restrictions. However, their large load that has already been deposited in the soil and bottom sediments can be remobilised and enter the food chain. The identification of factors favouring this process is very important, especially during the period of adopting new legal regulations on limiting the emission of pollutants. It became possible in February 2018 during the persistence of ice cover on the lagoon's surface. This allowed observation of processes, the effect of which in the absence of ice is blurred by wind mixing water. Therefore, an investigation of sources of 25 elements in a lagoon of the southern Baltic has been undertaken, based on the example of the Vistula Lagoon. The results point to the remobilisation of chemical elements (including the toxic ones) from land and bottom sediments, where they have been deposited for decades. These processes led to the accumulation of metals in certain areas of the lagoon. It may result in their uptake and accumulation in the benthic organisms inhabiting the lagoon and further transfer in the food chain. It is of major importance as the lagoons in the southern Baltic fulfil many essential functions in the scope of tourism, economy, and fishery. Thanks to restrictions on the quality of wastewater and the emission of pollutants, it has been noticed a substantial "purifying" effect of rivers, too.

Surgical wounds resulting from biofilm-producing microorganisms represent a major healthcare problem that requires new and innovative treatment methods. Rifampin is one of a small number of antibiotics that is able to penetrate such biofilms, and its local administration has the potential to serve as an ideal surgical site infection protection and/or treatment agent. This paper presents two types (homogeneous and sandwich structured) of rifampin-releasing carbodiimide-cross-linked fresh water fish collagen wound dressings.