Unveiling the molecular mechanisms of pigmentation control in Queen Loach, Botia dario (Hamilton, 1822): Insights from sesame seed and marigold-induced antityrosinase effects.

Fish pigmentation study can reveal understandings in dermatological research based on functional genomics. Cultured ornamental fish becomes dull coloured and antityrosinase activity through sesame seed may enhance skin colour, which has not been studied. Botia dario is an indigenous fish, having ornamental and aesthetic value and can be studied as a model for fish pigmentation genetics. In this study, fish specimens were fed with 15% marigold petal meal along with 5, 10 and 15% w/w sesame seed in diet. Pigmentation genes, that is, tyr, tyrp1a, asip1, gnaq, kitlga, mc1r, mitf, pax7a, rab38, slc7a11, sox9a, sox10, csf1r, bcdo2 and gsta2 in skin and immunogens, that is, il20, nramp, tlr9 and trail in kidney were studied. Gene expression in tissues revealed enhanced pigmentation and immunity as well as the role of tyr, tyrp1a and asip1 in pigmentation. Immunogenes and blood parameters confirmed the best pigmentation diet. Colorimetric analysis also showed the enhancement of pigmentation. Insights from sesame seed and marigold-induced antityrosinase effects will be applied in aquaculture to develop natural, dietary formulations that will enhance pigmentation in ornamental fish, leading to improved skin colour and market value.

Whole genome sequence analysis of shallot virus X from India reveals it to be a natural recombinant with positive selection pressure.

BACKGROUND: Shallots are infected by various viruses like Onion yellow dwarf virus (OYDV), Leek yellow stripe virus (LYSV), Shallot latent virus (SLV) and Shallot virus X (ShVX). In India, they have been found to be persistently infected by ShVX. ShVX also infects onion and garlic in combination with other carlaviruses and potyviruses. ShVX is a member of genus Allexivirus of family Alphaflexiviridae. ShVX has a monopartite genome, which is represented by positive sense single-stranded RNA. Globally, only six complete and 3 nearly complete genome sequences of ShV X are reported to date. This number is insufficient to measure a taxon's true molecular diversity. Moreover, the complete genome sequence of ShVX from Asia has not been reported as yet. Therefore, this study was undertaken to generate a complete genome sequence of ShVX from India. RESULTS: Shallot virus X (ShVX) is one of the significant threats to Allium crop production. In this study, we report the first complete genome sequence of the ShVX from India through Next-generation sequencing (NGS). The complete genome of the ShVX (Accession No. OK104171), from this study comprised 8911 nucleotides. In-silico analysis of the sequence revealed variability between this isolate and isolates from other countries. The dissimilarities are spread all over the genome specifically some non-coding intergenic regions. Statistical analysis of individual genes for site-specific selection indicates a positive selection in NABP region. The presence of a recombination event was detected in coat protein region. The sequence similarity percentage and phylogenetic analysis indicate ShVX Indian isolate is a distinctly different isolate. Recombination and site-specific selection may have a function in the evolution of this isolate. This is the first detailed study of the ShVX complete genome sequence from Southeast Asia. CONCLUSION: This study presents the first report of the entire genome sequence of an Indian isolate of ShVX along with an in-depth exploration of its evolutionary traits. The findings highlight the Indian variant as a naturally occurring recombinant, emphasizing the substantial role of recombination in the evolution of this viral species. This insight into the molecular diversity of strains within a specific geographical region holds immense significance for comprehending and forecasting potential epidemics. Consequently, the insights garnered from this research hold practical value for shaping ShVX management strategies and providing a foundation for forthcoming studies delving into its evolutionary trajectory.

A review on structure-function mechanism and signaling pathway of serine/threonine protein PIM kinases as a therapeutic target.

The proviral integration for the Moloney murine leukemia virus (PIM) kinases, belonging to serine/threonine kinase family, have been found to be overexpressed in various types of cancers, such as prostate, breast, colon, endometrial, gastric, and pancreatic cancer. The three isoforms PIM kinases i.e., PIM1, PIM2, and PIM3 share a high degree of sequence and structural similarity and phosphorylate substrates controlling tumorigenic phenotypes like proliferation and cell survival. Targeting short-lived PIM kinases presents an intriguing strategy as in vivo knock-down studies result in non-lethal phenotypes, indicating that clinical inhibition of PIM might have fewer adverse effects. The ATP binding site (hinge region) possesses distinctive attributes, which led to the development of novel small molecule scaffolds that target either one or all three PIM isoforms. Machine learning and structure-based approaches have been at the forefront of developing novel and effective chemical therapeutics against PIM in preclinical and clinical settings, and none have yet received approval for cancer treatment. The stability of PIM isoforms is maintained by PIM kinase activity, which leads to resistance against PIM inhibitors and chemotherapy; thus, to overcome such effects, PIM proteolysis targeting chimeras (PROTACs) are now being developed that specifically degrade PIM proteins. In this review, we recapitulate an overview of the oncogenic functions of PIM kinases, their structure, function, and crucial signaling network in different types of cancer, and the potential of pharmacological small-molecule inhibitors. Further, our comprehensive review also provides valuable insights for developing novel antitumor drugs that specifically target PIM kinases in the future. In conclusion, we provide insights into the benefits of degrading PIM kinases as opposed to blocking their catalytic activity to address the oncogenic potential of PIM kinases.

Metagenomic landscape of sediments of river Ganga reveals microbial diversity, potential plastic and xenobiotic degradation enzymes.

The Ganga is the largest river in India, serves as a lifeline for agriculture, drinking water, and religious rites. However, it became highly polluted due to the influx of industrial wastes and untreated sewages, leading to the decline of aquatic biodiversity. This study investigated the microbial diversity and plastic-xenobiotic degrading enzymes of six sediment metagenomes of river Ganga at Prayagraj (RDG, TSG, SDG) and Devprayag (KRG, BNG, BRG). The water quality parameters, higher values of BOD (1.8-3.7 ppm), COD (23-29.2 ppm) and organic carbon (0.18-0.51%) were recorded at Prayagraj. Comparative analysis of microbial community structure between Prayagraj and Devprayag revealed significant differences between Bacteroidetes and Firmicutes, which emerging as the predominant bacterial phyla across six sediment samples. Notably, their prevalence was highest in the BRG samples. Furthermore, 25 OTUs at genus level were consistent across all six samples. Alpha diversity exhibited minimal variation among samples, while beta diversity indicated an inverse relationship between species richness and diversity. Co-occurrence network analysis established that genera from the same and different groups of phyla show positive co-relations with each other. Thirteen plastic degrading enzymes, including Laccase, Alkane-1 monooxygenase and Alkane monooxygenase, were identified from six sediment metagenomes of river Ganga, which can degrade non-biodegradable plastic viz. Polyethylene, Polystyrene and Low-density Polyethelene. Further, 18 xenobiotic degradation enzymes were identified for the degradation of Bisphenol, Xylene, Toluene, Polycyclic aromatic hydrocarbon, Styrene, Atrazene and Dioxin etc. This is the first report on the identification of non-biodegradable plastic degrading enzymes from sediment metagenomes of river Ganga, India. The findings of this study would help in pollution abatement and sustainable management of riverine ecosystem.

Recent Progress and Prospect of Metal-Organic Framework-Based Nanozymes in Biomedical Application.

A nanozyme is a nanoscale material having enzyme-like properties. It exhibits several superior properties, including low preparation cost, robust catalytic activity, and long-term storage at ambient temperatures. Moreover, high stability enables repetitive use in multiple catalytic reactions. Hence, it is considered a potential replacement for natural enzymes. Enormous research interest in nanozymes in the past two decades has made it imperative to look for better enzyme-mimicking materials for biomedical applications. Given this, research on metal-organic frameworks (MOFs) as a potential nanozyme material has gained momentum. MOFs are advanced hybrid materials made of inorganic metal ions and organic ligands. Their distinct composition, adaptable pore size, structural diversity, and ease in the tunability of physicochemical properties enable MOFs to mimic enzyme-like activities and act as promising nanozyme candidates. This review aims to discuss recent advances in the development of MOF-based nanozymes (MOF-NZs) and highlight their applications in the field of biomedicine. Firstly, different enzyme-mimetic activities exhibited by MOFs are discussed, and insights are given into various strategies to achieve them. Modification and functionalization strategies are deliberated to obtain MOF-NZs with enhanced catalytic activity. Subsequently, applications of MOF-NZs in the biosensing and therapeutics domain are discussed. Finally, the review is concluded by giving insights into the challenges encountered with MOF-NZs and possible directions to overcome them in the future. With this review, we aim to encourage consolidated efforts across enzyme engineering, nanotechnology, materials science, and biomedicine disciplines to inspire exciting innovations in this emerging yet promising field.

Evaluation of biocontrol efficacy of rhizosphere dwelling bacteria for management of Fusarium wilt and Botrytis gray mold of chickpea.

BACKGROUND: Chickpea (Cicer arietinum L.) production is affected by many biotic factors, among them Fusarium wilt caused by Fusarium oxysporum f. sp. ciceri and Botrytis gray mold caused by Botrytis cinerea led to severe losses. As fungicide application is not advisable, biological management is the best alternative for plant protection. The rhizosphere-dwelling antagonistic bacteria are one of the important successful alternative strategy to manage these diseases of chickpea. Rhizosphere dwelling bacteria serve as biocontrol agents by different mechanisms like producing antibiotics, different enzymes, siderophores against pathogens and thereby reducing the growth of pathogens. RESULTS: The present study aimed to isolate rhizospheric bacteria from the soils of different chickpea fields to evaluate biocontrol efficacy of the isolated bacteria to manage Fusarium wilt and Botrytis gray mold in chickpea. A total of 67 bacteria were isolated from chickpea rhizosphere from Bundelkhand region of India. Study revealed the isolated bacteria could reduce the Fusarium oxysporum f. sp. ciceris and Botrytis cinerea infection in chickpea between 17.29 and 75.29%. After screening of all the bacteria for their biocontrol efficacy, 13 most promising bacterial isolates were considered for further study out of which, three bacterial isolates (15d, 9c and 14a) have shown the maximum in vitro antagonistic effects against Fusarium oxysporum f. sp. ciceri and Botrytis cinerea comparable to in vivo effects. However, Isolate (15d) showed highest 87.5% and 82.69% reduction in disease against Fusarium wilt and Botrytis gray mold respectively, under pot condition. Three most potential isolates were characterized at molecular level using 16S rRNA gene and found to be Priestia megaterium (9c and 14a) and Serratia marcescens (15d). CONCLUSION: This study identified two native biocontrol agents Priestia megaterium and Serratia marcescens from the rhizospheric soils of Bundelkhand region of India for control of Fusarium wilt, Botrytis gray mold. In future, efforts should be made to further validate the biocontrol agents in conjugation with nanomaterials for enhancing the synergistic effects in managing the fungal diseases in chickpea. This study will definitely enhance our understanding of these bioagents, and to increase their performance by developing effective formulations, application methods, and integrated strategies.

Cr-Detector: A simple chemosensing system for onsite Cr (VI) detection in water.

Due to the increase in urbanization and industrialization, the load of toxicants in the environment is alarming. The most common toxicants, including heavy metals and metalloids such as hexavalent Chromium, have severe pathophysiological impacts on humans and other aquatic biotas. Therefore, developing a portable rapid detection device for such toxicants in the aquatic environment is necessary. This work portrays the development of a field-portable image analysis device coupled with 3,3',5,5'-tetramethylbenzidine (TMB) as a sensing probe for chromium (VI) detection in the aquatic ecosystem. Sensor parameters, such as reagent concentration, reaction time, etc., were optimized for the sensor development and validation using a commercial UV-Vis spectrophotometer. The chemoreceptor integrated with a uniform illumination imaging system (UIIS) revealed the system's applicability toward Cr(VI) detection. The calibration curve using the R-value of image parameters allows Cr(VI) detection in the linear range of 25 to 600 ppb, which covers the prescribed permissible limit by various regulatory authorities. Furthermore, the adjusted R2 = 0.992 of the linear fit and correlation coefficients of 0.99018 against the spectrophotometric method signifies the suitability of the developed system. This TMB-coupled field-portable sensing system is the first-ever reported image analysis-based technology for detecting a wide range of Cr(VI) in aquatic ecosystems to our knowledge.

Structural insights of Labeo catla (catla) myxovirus resistance protein,GTP binding recognition and constitutive expression induced with Poly I:C.

The Myxovirus resistance (Mx) proteins are critical effectors belonging to the super-family of guanidine triphosphatase, often stimulated by type I interferon (IFN) and mediates antiviral responses to restrict the replication of numerous viral genes in fishes. In teleosts, Mx proteins display diverse and complicated antiviral activity in different species. The present investigation seeks to characterize the Mx gene from Labeo catla upon induction by double-stranded (ds) RNA, polyinosinic-polycytidylic acid, (poly I: C). Molecular modeling and all-atoms molecular dynamics (MD) simulations were employed to understand the architecture of the GTPase domain and its plausible mode of GTP recognition in Mx protein. The full-length L. catla Mx (LcMx) gene sequence (1821 bp nucleotides) encodes an open reading frame of 606 amino acids. Domain search indicated conserved tripartite domain architecture of LcMx and forms a major cluster with the Mx from other teleosts. The positively charged Arginine and polar Glutamine residues from helix 3 and 4 of stalk region LcMx aid in homo-oligomerization. MD simulation portrayed the role of conserved critical residues aid in GTP recognition by the GTPase domain which perfectly corroborates with experimental findings and prior MD studies. After injection of poly I:C, the temporal mRNA profile showed that LcMx expression was significantly elevated in the spleen, brain, kidney, liver, muscle, heart, intestine, and gill tissues. Collectively, these results suggest that the elevated expression of the major innate immune defense gene Mx was able to inhibit the poly I: C mediated virulence in fish.Communicated by Ramaswamy H. Sarma.

Unveiling the Microbiome Landscape: A Metagenomic Study of Bacterial Diversity, Antibiotic Resistance, and Virulence Factors in the Sediments of the River Ganga, India.

The global rise in antibiotic resistance, fueled by indiscriminate antibiotic usage in medicine, aquaculture, agriculture, and the food industry, presents a significant public health challenge. Urban wastewater and sewage treatment plants have become key sources of antibiotic resistance proliferation. The present study focuses on the river Ganges in India, which is heavily impacted by human activities and serves as a potential hotspot for the spread of antibiotic resistance. We conducted a metagenomic analysis of sediment samples from six distinct locations along the river to assess the prevalence and diversity of antibiotic resistance genes (ARGs) within the microbial ecosystem. The metagenomic analysis revealed the predominance of Proteobacteria across regions of the river Ganges. The antimicrobial resistance (AMR) genes and virulence factors were determined by various databases. In addition to this, KEGG and COG analysis revealed important pathways related to AMR. The outcomes highlight noticeable regional differences in the prevalence of AMR genes. The findings suggest that enhancing health and sanitation infrastructure could play a crucial role in mitigating the global impact of AMR. This research contributes vital insights into the environmental aspects of antibiotic resistance, highlighting the importance of targeted public health interventions in the fight against AMR.

Influence of stocking density and environmental factors on the expression of insulin-like growth factors in cage-reared butter catfish (Ompok bimaculatus, Bloch 1794) within a large reservoir ecosystem.

In vertebrates, insulin-like growth like factors (IGFs) play an important role in growth and other physiological processes. The GH-IGF axis is considered a valuable tool to monitor fish growth performance. Herein, we report the molecular characterization of igf-1, igf-2, and ß-actin transcripts and relative expression of igf-1 and igf-2 in the liver and muscle tissue of cage-reared butter catfish, Ompok bimaculatus, in response to different stocking densities (T1, 15 fingerlings m-3; T2, 25 fingerlings m-3; and T3, 35 fingerlings m-3) over 180 days of culture duration. The length of the partial amplified transcript sequence of Obigf-1, Obigf-2, and Obß-actin was 325, 438, and 924 bp, respectively. Phylogenetically, Obigf-1 and Obigf-2 were closely clustered with catfishes, viz., Clarias magur, Bagarius yarrelli, and Silurus asotus. The expression of igf-1 was significantly downregulated in the liver at higher densities after 120 days as biomass in the cages increased, while igf-2 expression did not change with the stocking densities over the culture period. Cortisol concentration was significantly elevated in T3 groups post 150 days of the culture period and correlated negatively with the expression of igf-1 (p < 0.05) and igf-2 (p > 0.05). Environmental parameters, pH, TDS, hardness, conductivity, and alkalinity showed a significant positive correlation with hepatic IGF expression. Our study indicates that the liver-derived igf-1 plays a more important role in the regulation of growth in response to culture density in the species studied, and thus, igf-1 can be used effectively as a biomarker for growth. Furthermore, this study will help in planning a proper harvest schedule and optimize the culture practices of O. bimaculatus in an open water cage system.

Effects of Di-(2-Ethylhexyl) Phthalate (DEHP) on Gamete Quality Parameters of Male Koi Carp (Cyprinus carpio).

In this study, we evaluated gamete quality parameters of mature male koi carp (Cyprinus carpio) exposed to three different concentrations (1, 10, and 100 µg/L) of di-(2-ethylhexyl) phthalate (DEHP). After 60 days of exposure, there was a significant decrease in the gonadosomatic index (GSI) of males exposed to 10 and 100 µg/L of DEHP. Histological analysis of the testes revealed impaired histoarchitecture, including inflammatory cells, intratubular vacuoles, and swollen seminiferous tubules in treatment groups. Gamete quality parameters like sperm production, motility, spermatocrit, and sperm density values were significantly decreased at the 10 and 100 µg/L concentrations. Biochemical compositions, including glucose, cholesterol, and total protein levels, were significantly changed in the treatment groups. Similarly, the ionic compositions of seminal fluid (Na, K, Ca, and Mg) also varied in the treatment groups. Furthermore, the 11-ketotestosterone levels were decreased, and the 17-ß estradiol levels were increased in the DEHP-treated groups. The mRNA expression levels of reproduction-related genes, including Fshr, Lhr, Ar, Erα, and Erß, were significantly changed in the DEHP-treated males in a dose-dependent manner. In conclusion, the findings of this study confirmed that environmentally relevant exposure to DEHP may contribute to a decline in the gamete quality of male fishes.

Identification of virulence-associated factors in Vibrio parahaemolyticus with special reference to moonlighting protein: a secretomics study.

Vibrio parahaemolyticus causes seafood-borne gastroenteritis infection in human which can even lead to death. The pathogenic strain of V. parahaemolyticus secretes different types of virulence factors that are directly injected into the host cell by a different type of secretion system which helps bacteria to establish its own ecological niche within the organism. Therefore, the aim of this study was to isolate the extracellular secreted proteins from the trh positive strain of V. parahaemolyticus and identify them using two-dimensional gel electrophoresis and MALDI-TOFMS/MS. Seventeen different cellular proteins viz, Carbamoyl-phosphate synthase, 5-methyltetrahydropteroyltriglutamate, tRNA-dihydrouridine synthase, Glycerol-3-phosphate dehydrogenase, Orotidine 5'-phosphate decarboxylase, Molybdenum import ATP-binding protein, DnaJ, DNA polymerase IV, Ribosomal RNA small subunit methyltransferase G, ATP synthase subunit delta and gamma, Ribosome-recycling factor, 4-hydroxy-3-methylbut-2-en-1-yl diphosphate synthase, tRNA pseudouridine synthase B, Ditrans, polycis-undecaprenyl-diphosphate synthase, Oxygen-dependent coproporphyrinogen-III oxidase, and Peptide deformylase 2 were identified which are mainly involved in different metabolic and biosynthetic pathways. Furthermore, the molecular function of the identified proteins were associated with catalytic activity, ligase activity, transporter, metal binding, and ATP synthase when they are intercellular. However, to understand the importance of these secreted proteins in the infection and survival of bacteria inside the host cell, pathogen-host protein-protein interactions (PPIs) were carried out which identified the association of eight secreted proteins with 41 human proteins involved in different cellular pathways, including ubiquitination degradation, adhesion, inflammation, immunity, and programmed cell death. The present study provides unreported strategies on host-cell environment's survival and adaptation mechanisms for the successful establishment of infections and intracellular propagation.

Sequencing and Characterization of M. morganii Strain UM869: A Comprehensive Comparative Genomic Analysis of Virulence, Antibiotic Resistance, and Functional Pathways.

Morganella morganii is a Gram-negative opportunistic Enterobacteriaceae pathogen inherently resistant to colistin. This species causes various clinical and community-acquired infections. This study investigated the virulence factors, resistance mechanisms, functional pathways, and comparative genomic analysis of M. morganii strain UM869 with 79 publicly available genomes. The multidrug resistance strain UM869 harbored 65 genes associated with 30 virulence factors, including efflux pump, hemolysin, urease, adherence, toxin, and endotoxin. Additionally, this strain contained 11 genes related to target alteration, antibiotic inactivation, and efflux resistance mechanisms. Further, the comparative genomic study revealed a high genetic relatedness (98.37%) among the genomes, possibly due to the dissemination of genes between adjoining countries. The core proteome of 79 genomes contains the 2692 core, including 2447 single-copy orthologues. Among them, six were associated with resistance to major antibiotic classes manifested through antibiotic target alteration (PBP3, gyrB) and antibiotic efflux (kpnH, rsmA, qacG; rsmA; CRP). Similarly, 47 core orthologues were annotated to 27 virulence factors. Moreover, mostly core orthologues were mapped to transporters (n = 576), two-component systems (n = 148), transcription factors (n = 117), ribosomes (n = 114), and quorum sensing (n = 77). The presence of diversity in serotypes (type 2, 3, 6, 8, and 11) and variation in gene content adds to the pathogenicity, making them more difficult to treat. This study highlights the genetic similarity among the genomes of M. morganii and their restricted emergence, mostly in Asian countries, in addition to their growing pathogenicity and resistance. However, steps must be taken to undertake large-scale molecular surveillance and to direct suitable therapeutic interventions.

An Improved Machine Learning-Based Approach to Assess the Microbial Diversity in Major North Indian River Ecosystems.

The rapidly evolving high-throughput sequencing (HTS) technologies generate voluminous genomic and metagenomic sequences, which can help classify the microbial communities with high accuracy in many ecosystems. Conventionally, the rule-based binning techniques are used to classify the contigs or scaffolds based on either sequence composition or sequence similarity. However, the accurate classification of the microbial communities remains a major challenge due to massive data volumes at hand as well as a requirement of efficient binning methods and classification algorithms. Therefore, we attempted here to implement iterative K-Means clustering for the initial binning of metagenomics sequences and applied various machine learning algorithms (MLAs) to classify the newly identified unknown microbes. The cluster annotation was achieved through the BLAST program of NCBI, which resulted in the grouping of assembled scaffolds into five classes, i.e., bacteria, archaea, eukaryota, viruses and others. The annotated cluster sequences were used to train machine learning algorithms (MLAs) to develop prediction models to classify unknown metagenomic sequences. In this study, we used metagenomic datasets of samples collected from the Ganga (Kanpur and Farakka) and the Yamuna (Delhi) rivers in India for clustering and training the MLA models. Further, the performance of MLAs was evaluated by 10-fold cross validation. The results revealed that the developed model based on the Random Forest had a superior performance compared to the other considered learning algorithms. The proposed method can be used for annotating the metagenomic scaffolds/contigs being complementary to existing methods of metagenomic data analysis. An offline predictor source code with the best prediction model is available at (https://github.com/Nalinikanta7/metagenomics).

Aeromonas veronii Is a Lethal Pathogen Isolated from Gut of Infected Labeo rohita: Molecular Insight to Understand the Bacterial Virulence and Its Induced Host Immunity.

A case of severe mortality in farmed Labeo rohita was investigated to characterize the causative agent. We identified the bacterial strain as Aeromonas veronii isolated from the gut of infected L. rohita by biochemical assay, scanning electron microscopy and 16S rRNA gene sequence analysis. The in vivo challenge experiment showed that the LD50 of A. veronii was 2.2 × 104 CFU/fish. Virulence gene investigation revealed that the isolated A. veronii possesses Aerolysin, Cytotoxic enterotoxin, Serine protease, Dnase and Type III secretion system genes. The isolated strain was resistant to two antibiotics (ampicillin and dicloxacillin) while susceptible to 22 other antibiotics. The study further revealed that A. veronii induced both stresses along with non-specific and specific immune responses marked by elevated cortisol HSP70, HSP90 and IgM levels in the treated L. rohita fingerlings. Although the bacterial pathogen enhances the immune response, the negative effect on fish, including stress, and high mortality, create concern and a need for A. veronii management in L. rohita farms. The knowledge gained from this study would facilitate future research aimed at assessing the pathogenicity of A. veronii, with an emphasis on microbial disease management in other farmed fish species.

Immunomodulatory Potency of Eclipta alba (Bhringaraj) Leaf Extract in Heteropneustes fossilis against Oomycete Pathogen, Aphanomyces invadans.

Aphanomyces invadans is an aquatic oomycete pathogen and the causative agent of epizootic ulcerative syndrome (EUS) in fresh and brackish water fish, which is responsible for severe mortalities and economic losses in aquaculture. Therefore, there is an urgent need to develop anti-infective strategies to control EUS. An Oomycetes, a fungus-like eukaryotic microorganism, and a susceptible species, i.e., Heteropneustes fossilis, are used to establish whether an Eclipta alba leaf extract is effective against the EUS-causing A. invadans. We found that treatment with methanolic leaf extract, at concentrations between 50-100 ppm (T4-T6), protects the H. fossilis fingerlings against A. invadans infection. These optimum concentrations induced anti-stress and antioxidative response in fish, marked by a significant decrease in cortisol and elevated levels of superoxide dismutase (SOD) and catalase (CAT) levels in treated animals, as compared with the controls. We further demonstrated that the A. invadans-protective effect of methanolic leaf extract was caused by its immunomodulatory effect and is linked to the enhanced survival of fingerlings. The analysis of non-specific and specific immune factors confirms that methanolic leaf extract-induced HSP70, HSP90 and IgM levels mediate the survival of H. fossilis fingerlings against A. invadans infection. Taken together, our study provides evidence that the generation of anti-stress and antioxidative responses, as well as humoral immunity, may play a role in protecting H. fossilis fingerlings against A. invadans infection. It is probable that E. alba methanolic leaf extract treatment might become part of a holistic strategy to control EUS in fish species.

Dietary silver nanoparticles as immunostimulant on rohu (Labeo rohita): Effects on the growth, cellular ultrastructure, immune-gene expression, and survival against Aeromonas hydrophila.

The current study aimed at assessing the immunostimulatory properties of silver nanoparticles (AgNPs) on Labeo rohita, and understanding how it affects the growth, cellular ultrastructure, the expression level of immune genes, and infection risk from Aeromonas hydrophila. Fish (avg wt: 30.1±3.26 g) were fed diets with four separate AgNP inclusion levels (0 µgKg-1 [basic diet, T1], 10 µgKg-1 [T2], 15 µgKg-1 [T3], and 20 µgKg-1 [T4]) for 56 days. After the feeding trial, growth, histological, immunological parameters, and protective immune response against A. hydrophila were assessed. The fish in the treatment groups including T1(control), the T3 growth indices, such as specific growth rate (7.56±0.26) and percent weight gain (231.05±3.21), was statistically higher (P < 0.05). In the immunological and oxidative parameters, levels of SOD and catalase decreased in correlation with a rise in the inclusion doses of AgNP in the liver, and a reduction in catalase values was recorded in the gill. With the addition of AgNP, the NBT value was decreased in the gill, and T3 had a considerably larger (P<0.05) value in the liver (0.493±0.02). The kidney of the L. rohita fed AgNP (0 and20 µgKg-1 AgNP) showed expansion through Bowman's gaps, severing of glomeruli with haemorrhage, as well as atrophic spots between its gaps. The liver showed fibrosis, karyolysis, and the removal of the hepatocytes wall. The gill, liver, kidney, and muscle of fish-fed diets supplemented with AgNP, showed that interleukin-8 (IL-8), and cyclooxygenase-2 (COX-2), were up-regulated. Expression was considerably higher in T3 compared with the control. However, the control group that wasn't given AgNP supplemented diet had increased levels of TGF-beta. Additionally, fish on the T3 diet showed much greater post-challenge survival rates (90%). These findings strongly suggest that dietary inclusion of AgNP (at 10 and 15 µgKg-1 feed) enhances growth, health, and protective immune response against A. hydrophila.

Bacteriophages diversity in India's major river Ganga: a repository to regulate pathogenic bacteria in the aquatic environment.

Bacteriophages are key viruses that can kill thousands of harmful microbes generally present at polluted sites. Such bacteriophages are abundantly present in the river Ganga, where millions of people in India and abroad drink its water and take baths every day for spiritual reasons. Besides bacteriophages, several pathogenic and zoonotic microbes are present in the river Ganga. It is interesting to study the diversity and abundance of bacteria and their respective phages present in polluted or non-polluted sites. Thus, the metagenomics study was carried out at the most polluted sites of river Ganga near Kanpur and non-polluted sites at Farakka, which harbors several harmful bacteria and their phages. The results revealed a significantly higher percentage of Microviridae phage family, ssDNA viruses, and Mimiviridae virus family near Kanpur than Farakka. In addition, compared to Kanpur, Farakka has a more significant percentage of Myoviridae, an unidentified phage family, and Retroviridae viral families. Despite heavy drainage of untreated and contaminated effluents from the leather industry, pesticide industry, paper mills, metropolitan cities, and other sources, the vast number of said phages kills several harmful pathogenic microbes in polluted sites to maintain the Ganga water's healing power or natural sterility. In a polluted aquatic environment, the varieties of bacteriophages were identified in the Ganga and their interaction with the microbial host. The taxonomic diversity of several bacteriophages found in pathogenic host systems was investigated to get exceptional knowledge of these small viruses in the aquatic environment.

Aptamer-based NanoBioSensors for seafood safety.

Chemical and biological contaminants are of primary concern in ensuring seafood safety. Rapid detection of such contaminants is needed to keep us safe from being affected. For over three decades, immunoassay (IA) technology has been used for the detection of contaminants in seafood products. However, limitations inherent to antibody generation against small molecular targets that cannot elicit an immune response, along with the instability of antibodies under ambient conditions greatly limit their wider application for developing robust detection and monitoring tools, particularly for non-biomedical applications. As an alternative, aptamer-based biosensors (aptasensors) have emerged as a powerful yet robust analytical tool for the detection of a wide range of analytes. Due to the high specificity of aptamers in recognising targets ranging from small molecules to large proteins and even whole cells, these have been suggested to be viable molecular recognition elements (MREs) in the development of new diagnostic and biosensing tools for detecting a wide range of contaminants including heavy metals, antibiotics, pesticides, pathogens and biotoxins. In this review, we discuss the recent progress made in the field of aptasensors for detection of contaminants in seafood products with a view of effectively managing their potential human health hazards. A critical outlook is also provided to facilitate translation of aptasensors from academic laboratories to the mainstream seafood industry and consumer applications.

Effects of dietary supplementation of Pseudomonas aeruginosa FARP72 on the immunomodulation and resistance to Edwardsiella tarda in Pangasius pangasius.

Edwardsiella tarda is one of the serious bacterial pathogens infecting both cultured and wild catfish urging an immediate need for effective protection strategies. This study assessed the effects of dietary supplementation of Pseudomonas aeruginosa FARP72 at 108 cells/g feed (PA diet) for 30 days on the innate immunity parameters, viz., respiratory oxidative burst (ROB) activity, lysozyme, ceruloplasmin, myeloperoxidase, in-vitro nitric oxide (NO) production in addition to the expression of immune genes encoding interleukin-1ß, C3 and transferrin in yellowtail catfish Pangasius pangasius and their resistance to Edwardsiella tarda challenge at a sub-lethal dose of 1.50 × 107 cells/fish. A significant increase in the innate immunity parameters was noted in PA diet-fed catfish on 30 dpf compared to the control. Post E. tarda challenge, the levels of immune parameters increased significantly and peaked at 5 dpi irrespective of feeding to confer protection against E. tarda. Their levels, however, decreased on and from 10 dpi. The results on the expression of immune genes encoding interleukin-1ß, C3 and transferrin in the kidney and liver tissue samples of PA diet-fed P. pangasius upon challenge with E. tarda further confirmed the ability of P. aeruginosa to stimulate primary immune organs at the gene level. The effects of feeding P. aeruginosa FARP72 on the immune functions of catfish as examined by the functional immune assays, thus, demonstrating the innate immune responses of catfish that are differentially stimulated by the PA diet. The findings of our study would help evolve management strategies to confer protection against E. tarda infection in commercial catfish aquaculture.