Insight into the gut microbiology of wild-caught Mangrove Red Snapper, Lutjanus argentimaculatus (Forsskal, 1775)

Documenting bacteria present in healthy individuals forms the first step in understanding the effects of microbial manipulation in aquaculture systems. Among the commensal microflora, gut microbiota has attracted extensive attention owing to their role in host metabolism and health maintenance. Basic knowledge on normal gut microbes within a particular host species is thus essential to determine how successfully these microbes can be manipulated and engineered for sustainable aquaculture systems. In spite of the good aquaculture potential of Mangrove red snapper, Lutjanus argentimaculatus, the information on microbial communities associated with the gut of this fish, and their contribution towards digestive efficiency and disease resistance is scarce. Therefore, an attempt was made to elucidate the abundance and diversity of cultivable gut microbes of wild caught L. argentimaculatus along with their digestive exoenzyme profiles and prohibitory effect against fish pathogens. Results on abundance showed similar gut bacterial loads as that of other marine fish imposing the less contribution of microflora to the volume of gut materials in fish. Eleven distinct bacterial species including two proposed novel vibrios were identified. An incidental observation of Morganella morganii throughout samples is an alarming signal, emphasizing the need for immediate de-gutting to avoid histamine intoxication. Abundance of digestive enzyme producers and excellent enzymatic potential of some isolates suggested the contribution of digestive enzymes may supplement to the symbiosis between gut flora and host and the information is of interest to aquaculture nutritionists/commercial industries. Interestingly, some isolates demonstrated estimable co-aggregation with aquatic pathogens, indicating their involvement in disease resistance and the results correlated well with gut microbial diversity. These findings highlight the significant role of gut microbes towards nutritional physiology and disease resistance of this aquaculture candidate in natural ecosystem. The culturable microbiota profiles of wild fish generated in the study can be applied for measuring the quality of husbandry routines in aquaculture facility of this marine fish. Overall, the present study fetches insights on the gut microbiome of healthy L. argentimaculatus which forms a platform for follow-up studies. The study may also help in the development of “functional” fish feeds for L. argentimaculatus. The investigation also demonstrated some potential digestive enzyme-producing isolates having probiotic applications in commercial aquaculture

Pathogenicity and pathobiology of Epizootic Ulcerative Syndrome (EUS) causing fungus Aphanomyces invadans and its immunological response in fish

Aphanomyces invadans, an oomycyte fungus most frequently recognized as a causative agent of epizootic ulcerative syndrome (EUS) is a seasonal epidemic pathogen of great importance in wild and farmed fish in both freshwater and estuarine environments. EUS is a complex infectious etiology which leads to necrosis ulcerative lesions and granulomatous response in fishes. It is a cause of death of approximately 92 species that has been recorded in wild as well as in commercial culture systems worldwide. Several environmental and biological factors are responsible for the growth and establishment of A. invadans, which further attracts secondary pathogens to enter the lesions thus, increasing the severity of the infection. Methods for the proper identification of A. invadans, includes PCR detection and microscopy. However, the pathogenicity of the A. invadans is still unknown. In order to discover new effective treatment to fight the disease, a better understanding of the infection process is necessary. The studies on fungal infection in fishes indicate the immune response pattern in fish against A. invadans that serves as an important key for the development of targeted therapeutics and vaccines to prevent the disease and to maintain EUS free aquaculture systems. The immune mechanisms that respond to stimulation, interaction between the immune system of host species and A. invadans, different factors of A. invadans and its pathogenicity as well as various approaches of treatment has been discussed in this review

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Not AvailableDocumenting bacteria present in healthy individuals forms the first step in understanding the effects of microbial manipulation in aquaculture systems. Among the commensal microflora, gut microbiota has attracted extensive attention owing to their role in host metabolism and health maintenance. Basic knowledge on normal gut microbes within a particular host species is thus essential to determine how successfully these microbes can be manipulated and engineered for sustainable aquaculture systems. In spite of the good aquaculture potential of Mangrove red snapper, Lutjanus argentimaculatus, the information on microbial communities associated with the gut of this fish, and their contribution towards digestive efficiency and disease resistance is scarce. Therefore, an attempt was made to elucidate the abundance and diversity of cultivable gut microbes of wild caught L. argentimaculatus along with their digestive exoenzyme profiles and prohibitory effect against fish pathogens. Results on abundance showed similar gut bacterial loads as that of other marine fish imposing the less contribution of microflora to the volume of gut materials in fish. Eleven distinct bacterial species including two proposed novel vibrios were identified. An incidental observation of Morganella morganii throughout samples is an alarming signal, emphasizing the need for immediate de-gutting to avoid histamine intoxication. Abundance of digestive enzyme producers and excellent enzymatic potential of some isolates suggested the contribution of digestive enzymes may supplement to the symbiosis between gut flora and host and the information is of interest to aquaculture nutritionists/commercial industries. Interestingly, some isolates demonstrated estimable co-aggregation with aquatic pathogens, indicating their involvement in disease resistance and the results correlated well with gut microbial diversity. These findings highlight the significant role of gut microbes towards nutritional physiology and disease resistance of this aquaculture candidate in natural ecosystem. The culturable microbiota profiles of wild fish generated in the study can be applied for measuring the quality of husbandry routines in aquaculture facility of this marine fish. Overall, the present study fetches insights on the gut microbiome of healthy L. argentimaculatus which forms a platform for follow-up studies. The study may also help in the development of “functional” fish feeds for L. argentimaculatus. The investigation also demonstrated some potential digestive enzyme-producing isolates having probiotic applications in commercial aquaculture.Not Availabl

A synthetic antioxidant molecule, GP13 derived from cysteine desulfurase of spirulina, Arthrospira platensis exhibited anti-diabetic activity on L6 rat skeletal muscle cells through GLUT-4 pathway

Objectives: Diabetes creates oxidative stress, which damages several organs and causes various problems including hyperglycemia, hyperlipidemia, hypertension, and maybe iron dyshomeostasis. Consequently, antioxidant therapy may be a promising strategy to avoid diabetes and diabetic complications. In the current study, we investigated the activity of the antioxidant GP13 peptide in an in-vitro diabetic model. Methods: All anti-diabetic and antioxidant in-vitro tests were performed on differentiated L6 myotubes cells. MTT assay was used to analyze the cytotoxic effect of the GP13 at different concentrations (10 μM to 80 μM) in the L6 cells. The DCFDA fluorescence was performed to confirm the radical scavenging effect of GP13 in the myotubule cells. The cells were treated with different concentrations of GP13 peptide before the enzyme assay was conducted. The differentiated L6 myotubes were kept for serum deprivation for 8 h before being treated with GP13 peptide. The RNA extraction from the L6 myotubes was performed using the Trizol reagent. Results: Cell viability analysis exhibited the non-toxic nature of GP13 in a dose-dependent manner (10 μM to 80 μM). Antioxidant enzyme, superoxide dismutase activity was 23.25 U/mL in the untreated group, whereas it was only 11.75 U/mL in the group that was exposed to GP13 at 80 μM. The catalase activity at 40 μM was slightly altered in the cells, while the hydrogen peroxide inhibition activity was higher (91.2%) compared to the control group. Additionally, GP13 showed anti-diabetic effects through a dose-dependent increase in glycogen storage (6.1 mM). It was discovered that 40 μM was the ideal concentration for the highest level of activity. Additionally, the genes involved in diabetes-related to antioxidants and the insulin signalling system were investigated. Conclusion: It is concluded that the GP13 peptide from A. platensis is a promising agent for anti-diabetic and antioxidant activities. To treat diabetes and its consequences, we thus propose that GP13 be regarded as a natural lead. The animal model design of this study has limitations, and further research is needed to draw conclusions about its therapeutic relevance to people

Pharmacological importance of TG12 from tachykinin and its toxicological behavior against multidrug-resistant bacteria Klebsiella pneumonia

Development of antimicrobial drugs against multidrug-resistant (MDR) bacteria is a great focus in recent years. TG12, a short peptide molecule used in this study was screened from tachykinin (Tac) protein of an established teleost Channa striatus (Cs) transcriptome. Tachykinin cDNA has 345 coding sequence, that denotes a protein contained 115 amino acids; in which a short peptide (TG12) was identified at 83–94. Tachykinin mRNA upregulated in C. striatus treated with Aeromonas hydrophila and Escherichia coli lipopolysaccharide (LPS). The mRNA up-regulation was studied using real-time PCR. The up-regulation tachykinin mRNA pattern confirmed the immune involvement of tachykinin in C. striatus during infection. Further, the identified peptide, TG12 was synthesized and its toxicity was demonstrated in hemolytic and cytotoxic assays using human erythrocytes and human dermal fibroblast cells, respectively. The toxicity study exhibited that the toxicity of TG12 was similar to negative control, phosphate buffer saline (PBS). Moreover, the antibiogram of TG12 was active against Klebsiella pneumonia ATCC 27736, a major MDR bacterial pathogen. Further, the antimicrobial activity of TG12 against pathogenic bacteria was screened using minimum inhibitory concentration (MIC) and anti-biofilm assays, altogether TG12 showed potential activity against K. pneumonia. Fluorescence assisted cell sorter flow cytometer analysis (FACS) and field emission scanning electron microscopy (FESEM) was carried on TG12 with K. pneumonia; the results showed that TG12 significantly reduced K. pneumonia viability as well as TG12 disrupt its membrane. In conclusion, TG12 of CsTac is potentially involved in the antibacterial immune mechanisms, which has a prospectus efficiency in pharma industry against MDR strains, especially K. pneumonia