Bacteria Aeromonas Hydrophila Research Articles

Effects of berberine hydrochloride on antioxidant response and gut microflora in the Charybdis japonica infected with Aeromonas hydrophila

This study used berberine hydrochloride to treat the Asian paddle crab, Charybdis japonica infected with the Gram-negative bacterium Aeromonas hydrophila at concentrations of 0, 100, 200 and 300 mg/L. The effect of berberine hydrochloride on the survival rate and gut microbiota of C. japonica was investigated. Berberine hydrochloride improved the stability of the intestinal flora, with an increase in the abundance of probiotic species and a decrease in the abundance of both pathogenic bacteria after treatment with high concentrations of berberine hydrochloride. Berberine hydrochloride altered peroxidase activity (POD), malondialdehyde (MDA), and lipid peroxidation (LPO) in the intestinal tract compared to the control. Berberine hydrochloride could modulate the energy released from the enzyme activities of hexokinase (HK), phosphofructokinase (PFK), and pyruvate kinase (PK) in the intestinal tract of C. japonica infected with A. hydrophila. Zona occludens 1 (ZO-1), Zinc finger E-box binding homeobox 1 (ZEB1), occludin and signal transducer, and activator of transcription5b (STAT5b) expression were also increased, which improved intestinal barrier function. The results of this study provide new insights into the role of berberine hydrochloride in intestinal immune mechanisms and oxidative stress in crustaceans.

Antimicrobial and anthelmintic effects of copper nanoparticles against Koi carp parasites and their toxicity.

This study investigated the invitro antimicrobial and anthelmintic effect of copper nanoparticles (CuNPs) against the bacterium Aeromonas hydrophila, the monogeneans Dactylogyrus minutus, Dactylogyrus extensus, Gyrodactylus cyprini, and the cestode Schyzocotyle acheilognathi, as well as their toxicity to Cyprinus carpio Koi. In the antimicrobial invitro test, the inhibition zone method and minimum inhibitory concentration (MIC) were performed. In order to determine the time and efficacy of monogenean parasite mortality, the parasites were exposed to CuNP concentrations of 20, 50, 100, 150, 200, and 300 mg L-1, and a control group with tank water and one with copper sulphate pentahydrate (CuSO4.5H2O) at a concentration of 0.3 mg L-1, performed in triplicate. The parasites were observed every 10 min for 300 min, and mortality was recorded. For the cestodes, parasites were immersed in CuNP concentrations of 50, 100, 150, and 300 mg L-1. At the end of the invitro tests, the anthelmintic efficacy of each treatment was calculated. To assess the tolerance and toxicity in fish, they were exposed to CuNP concentrations of 0.6, 1.25, 2.5, 5, 10, 20, and 50 mg L-1 for 12 h. The MIC demonstrated that CuNPs effectively inhibited the growth of A. hydrophila up to a dilution of 12,500 mg L-1 and showed an inhibition zone of 14.0 ± 1.6 mm for CuNPs. The results of anthelmintic activity showed a dose-dependent effect of concentration for both groups of parasites, with the most effective concentration being 300 mg L-1 in 120 min. In the toxicity test, the carps showed tolerance to lower concentrations. The study indicated that CuNPs were effective against the studied pathogens. However, it proved to be toxic to fish at high concentrations. The use of low concentrations is recommended still requires further investigation.

Synergistic toxic effects of copper sulfate and trichlorfon on the health and intestinal microbiota of gibel carp Carassius auratus gibelio

In the high-density pond aquaculture of gibel carp (Carassius auratus gibelio) in China, copper sulfate (CuSO4) and trichlorfon (Tri) are commonly used, either in combination or alternately, to prevent and control various diseases and harmful algae. Despite their widespread use, there is a lack of studies on the toxic effects of CuSO4 and Tri on gibel carp, particularly regarding their combined application. This study assessed the effects of exposure to CuSO4 (0.5 mg/L) and Tri (0.5 mg/L), both individually and in combination, on gibel carp over 21 days. Histopathological assessments revealed significant structural damage to the liver and intestines in gibel carp exposed to either CuSO4 or Tri alone, with co-exposure notably intensifying these effects. Analysis of antioxidant enzyme activities revealed a substantial reduction in the liver and intestines, concurrent with a significant rise in the oxidative stress marker malondialdehyde in both single and combined exposure groups. Moreover, quantitative PCR analyses indicated a downregulation of immune-related genes post-exposure, with the combined treatment causing more severe suppression. This suppressed immune response correlated with a reduced ability to resist infection by the pathogenic bacterium Aeromonas hydrophila, particularly in the combined exposure group. This indicates that long-term exposure to CuSO4 and Tri, particularly in combination, induces significant oxidative stress damage in the liver and intestinal tissues, suppresses immune function, and reduces disease resistance. Additionally, 16S rRNA sequencing of the intestinal microbiota revealed that CuSO4 and Tri exposure altered the diversity and composition of intestinal microbial communities, potentially bringing both benefits and drawbacks. These findings underscore the need for careful management of CuSO4 and Tri in aquaculture to mitigate their adverse impacts, especially when used in combination for an extended period.

Ice nucleation active bacteria metabolites as antibiofilm agent to control Aeromonas hydrophila and Streptococcus agalactiae infections in Aquaculture

ObjectivesThe aim of this study was to quantify and identify metabolites of Ice Nucleation Active (INA) bacteria as an anti-biofilm agent against biofilms of fish pathogens such as Aeromonas hydrophila and Streptococcus agalactiae.ResultsIce nucleation active bacteria, which have the ability to catalyze ice nucleation, isolated from rainwater in previous studies, were used. All INA isolates were tested in several assays, including the antimicrobial test, which uses streptomycin as the positive control and none of the isolates were found positive in the antimicrobial test. As for the quorum quenching assay, it was found that four out of ten isolates were able to disturb the communication system in Chromobacterium violaceum wild type, which was used as the indicator bacteria. On the next assay, all ten isolates were tested for Biofilm Inhibition and Destruction and showed anti-biofilm activity with the highest percentage inhibition of 33.49% by isolate A40 against A. hydrophila and 77.26% by isolate A19 against S. agalactiae. C1 performed the highest destruction against A. hydrophila and S. agalactiae, with percentages of 32.11% and 51.88%, respectively. As for the GC-MS analysis, supernatants of INA bacteria contain bioactive compounds such as sarcosine and fatty acids, which are known to have antibiofilm activity against several biofilm-forming bacteria. Through 16s rRNA sequencing, identified bacteria are from the Pantoea, Enterobacter, and Acinetobacter genera. As for the conclusion, ice nucleation active bacteria metabolites tested showed positive results against pathogenic bacteria Aeromonas hydrophila and Streptococcus agalactiae in destructing and inhibiting biofilm growth.

Immunomodulatory Effects of Mallotus japonicus Extract on Innate Immune Responses in HeteroTilapia buttikoferi Infected with Aeromonas hydrophila

The intensive use of antibiotics in modern aquaculture has been linked to the emergence of multidrug resistance in human health. Despite continuous caution against such use by farmers, antibiotics serve as the primary means of disease control in aquaculture. In this study, we explore the potential of medicinal plant extracts as immunomodulant in enhancing the innate immune defense of a fish host, HeteroTilapia buttikoferi, infected with the prevalent fish pathogenic bacteria Aeromonas hydrophila. Our previous research reveals the bactericidal activity of the medicinal plant, Mallotus japonicus, against the pathogen, but its effectiveness as a prophylactic in enhancing host immune defense has not yet been investigated. Therefore, the objective of this study is to address this knowledge gap.By our findings, it was uncovered that the supplementation of the diethyl ether extract of the plant’s bark as an additive in the fish diet significantly improved the innate immune defense by upregulating the total levels of lysozyme, serum bactericidal activity, globulin and albumin levels, total protein, phagocytosis, respiratory burst activity and overall survival. A dose-dependent increase in immunological parameters was recorded, and this was in sharp contrast to the control group.These findings suggest that M. japonicus has the potential of use to enhance the innate immune defense of H. buttikoferi against the pervasive fish pathogenic bacteria, Aeromonas hydrophila. The improvements in immune parameters indicate the ability of M. japonicus extract to strengthen the hosts to combat bacterial infections.

Isolation, characterization and functional analysis of a bacteriophage targeting Culex pipiens pallens resistance-associated Aeromonas hydrophila

BackgroundCulex pipiens pallens is a well-known mosquito vector for several diseases. Deltamethrin, a commonly used pyrethroid insecticide, has been frequently applied to manage adult Cx. pipiens pallens. However, mosquitoes can develop resistance to these insecticides as a result of insecticide misuse and, therefore, it is crucial to identify novel methods to control insecticide resistance. The relationship between commensal bacteria and vector resistance has been recently recognized. Bacteriophages (= phages) are effective tools by which to control insect commensal bacteria, but there have as yet been no studies using phages on adult mosquitoes. In this study, we isolated an Aeromonas phage vB AhM-LH that specifically targets resistance-associated symbiotic bacteria in mosquitoes. We investigated the impact of Aeromonas phage vB AhM-LH in an abundance of Aeromonas hydrophila in the gut of Cx. pipiens pallens and its effect on the status of deltamethrin resistance.MethodsPhages were isolated on double-layer agar plates and their biological properties analyzed. Phage morphology was observed by transmission electron microscopy (TEM) after negative staining. The phage was then introduced into the mosquito intestines via oral feeding. The inhibitory effect of Aeromonas phage vB AhM-LH on Aeromonas hydrophila in mosquito intestines was assessed through quantitative real-time PCR analysis. Deltamethrin resistance of mosquitoes was assessed using WHO bottle bioassays.ResultsAn Aeromonas phage vB AhM-LH was isolated from sewage and identified as belonging to the Myoviridae family in the order Caudovirales using TEM. Based on biological characteristics analysis and in vitro antibacterial experiments, Aeromonas phage vB AhM-LH was observed to exhibit excellent stability and effective bactericidal activity. Sequencing revealed that the Aeromonas phage vB AhM-LH genome comprises 43,663 bp (51.6% CG content) with 81 predicted open reading frames. No integrase-related gene was detected in the vB AH-LH genome, which marked it as a potential biological antibacterial. Finally, we found that Aeromonas phage vB AhM-LH could significantly reduce deltamethrin resistance in Cx. pipiens pallens, in both the laboratory and field settings, by decreasing the abundance of Aeromonas hydrophila in their midgut.ConclusionsOur findings demonstrate that Aeromonas phage vB AhM-LH could effectively modulate commensal bacteria Aeromonas hydrophila in adult mosquitoes, thus representing a promising strategy to mitigate mosquito vector resistance.Graphical

Sargassum sp. extract improve hematological profile of tilapia fish (Oreochromis niloticus)

Background Strategies to increase body resistance and prevent disease in aquaculture include using vaccines, antibiotics, and probiotics. Today, the use of antibiotics with natural ingredients is becoming a trend. Sargassum sp is a natural ingredient that contains high antioxidants and antibiotics. Methods This research was conducted from March to May 2022 at the Biotechnology Laboratory, Faculty of Fisheries and Marine, Universitas Riau, in two stages: 1) the sensitivity of extracts of Sargassum sp. and 2) the application of Sargassum sp. extract orally in tilapia (O. niloticus). The parameters measured were clear zone, minimum inhibitory concentration, LD50 test of leaf extract of Sargassum sp. in tilapia (O. niloticus), hemoglobin levels, hematocrit, total leukocytes, total erythrocytes, leukocyte differentiation, and survival rate. Data on hematology parameters were tabulated and analyzed using a One-Way ANOVA followed by a Student Newman Keuls (SNK) test when deemed necessary. Results The results showed that the extract of Sargassum sp. inhibited the growth of Aeromonas hydrophila bacteria with a clear zone of 6.5-15.0 mm, which is classified as resistant. At doses of 2000, 2500, and 3000 ppm, it did not cause death in fish for 96 hours (LD50). Hematological parameters can be a sign of the health status of fish. Tilapia given Sargassum sp. in different doses gave an effect between treatments after 30 days of rearing and post-test against A. hydrophila bacteria (p<0.05). The results showed that the hematology of fish fed with Sargassum sp. extract was in the normal or healthy range. Healthy tilapia had erythrocyte counts ranging from 1.34-2.11×106 cells/mm3, hematocrit 26.17-33.19%, hemoglobin 6.26-11.2 g/dL and total leukocytes 1.01-1.50×104 cells/mm3 and total erythrocytes 5.88-9.13×104 cells/ mm3. Conclusions A dose of 3000 ppm provided the highest health improvement against A. hydrophila bacterial infection.

Terminalia arjuna Bark Powder as a Potential Immunomodulator in Labeo rohita: Enhanced Hematological, Adaptive, and Humoral Responses against Bacterial Pathogens and Concordant Liver Histomorphology.

This study investigated the dietary immunomodulatory effects of Terminalia arjuna bark powder (TABP) in Labeo rohita, a freshwater fish model. Four iso-nitrogenous and iso-caloric diets containing graded levels of TABP (0, 1, 10, and 15 g/kg were fed to fish for 90 days, followed by a 10 day challenge with pathogenic bacteria Aeromonas hydrophila and Edwardsiella tarda. An integrated biomarker response (IBR) approach assessed the impact of TABP on hematological, adaptive, and humoral immune parameters, along with liver histomorphology. Dietary TABP at 10 g/kg significantly enhanced (p < 0.05) hematological indices (hemoglobin, red blood cell count, hematocrit), specific immune parameters (lysosomal enzyme activity, phagocytosis, respiratory burst), and non-specific immune parameters (serum lysozyme, alternative complement activity), and exhibited improvements in liver architecture consistent with the enhanced immune response. Broken line regression analysis showed 11.5 g/kg to be an optimum dose. However, at 15 g/kg, a compromised trend was observed in some parameters. These findings suggest an optimal dosage range for TABP's immunomodulatory effects. The study highlights the potential of TABP as a natural immunomodulator in fish aquaculture. The improved immune response and concomitant liver health observed in Labeo rohita opens avenues for further research on TABP's applicability in animal health, using fish as a model organism. Additionally, the IBR approach proved effective in evaluating TABP's immunomodulatory properties, paving the way for similar studies on other natural products in aquaculture.

Deciphering genome-wide molecular pathways for exogenous Aeromonas hydrophila infection in wide-bodied sand loach (Sinibotia reevesae)

Aquaculture, as a rapidly growing industry, plays a significant role in global food production and economic development. However, various infectious diseases, particularly those caused by the gram-negative bacterium Aeromonas hydrophila, pose a critical threat to the sustainability and productivity of world-wide aquaculture operations. Investigating the molecular mechanisms of A. hydrophila infection can help to identify key targets for therapeutic interventions and vaccines, thereby reducing economic losses associated with disease outbreaks. Our present study focuses on wide-bodied sand loach (WBSL, Sinibotia reevesae), a captive-bred commercial fish, to explore detailed molecular effects of exogenous A. hydrophila infection. Firstly, a high-quality chromosome-level haplotype genome with a total length of 774 Mb and 49 chromosomes was assembled, providing valuable insights into its genetic components. Secondly, we isolated and characterized a newfound A. hydrophila F4S strain, examined pathological symptoms of WBSL after infection, and then investigated dynamic gene expressions. Our results revealed that the bacterial infection decreased metabolic activity, causing disruptions in cardiac function, cellular homeostasis, tissue damages, and impaired energy utilization. The immune system responds multifaceted, potentially impacting overall health and survival. In summary, our findings contribute to the understanding of the complicated interactions between WBSL and exogenous A. hydrophila, especially shed lights on the genetic complexity, immune responses, and potential impacts on fish health and survival. Furthermore, this study provides new insights into the mechanisms underlying A. hydrophila infection, and offers potential strategies to offload corresponding pathological effects, not only in WBSL but also in other aquaculture species.

The The effectiveness of galangal (Alpinia galanga) extract for the treatment of sangkuriang catfish (Clarias gariepinus) infected Aeromonas hydrophila

The purpose of this research is to find out the optimal dose of galangal extract to treatment of sangkuriang catfish infected with Aeromonas hydrophila, the fish fry used are 5-7 cm in size. October-November 2022 was the time the research was carried out. The experimental method used in this study was a completely randomized design (CRD) with 4 treatments and 3 replications. The treatment used was immersing with galangal extract for 24 hours with doses of 0 mg/L (A), 250 mg/L (B), 500 mg/L (C) and 750 mg/L (D). Maintenance of test fish for 14 days. Aeromonas hydrophila bacteria are used to infect fish with a density of 108 CFU/ml by immersing 10 ml in 10 liters of water. Clinical symptoms of infection, clinical symptoms of recovery period, survival rate and water quality were used as parameters in this research. The results showed that the use of galangal extract for treatment of sangkuriang catfish fry infected with Aeromonas hydrophila by immersion method for 24 hours at a concentration of 500 mg/L was the best treatment with the survival rate of 90%.

Sargassum sp. extract improve hematological profile of tilapia fish (Oreochromis niloticus)

Background Strategies to increase body resistance and prevent disease in aquaculture include using vaccines, antibiotics, and probiotics. Today, the use of antibiotics with natural ingredients is becoming a trend. Sargassum sp is a natural ingredient that contains high antioxidants and antibiotics. Methods This research was conducted from March to May 2022 at the Biotechnology Laboratory, Faculty of Fisheries and Marine, Universitas Riau, in two stages: 1) the sensitivity of extracts of Sargassum sp. and 2) the application of Sargassum sp. extract orally in tilapia (O. niloticus). The parameters measured were clear zone, minimum inhibitory concentration, LD50 test of leaf extract of Sargassum sp. in tilapia (O. niloticus), hemoglobin levels, hematocrit, total leukocytes, total erythrocytes, leukocyte differentiation, and survival rate. Data on hematology parameters were tabulated and analyzed using a One-Way ANOVA followed by a Student Newman Keuls (SNK) test when deemed necessary. Results The results showed that the extract of Sargassum sp. inhibited the growth of Aeromonas hydrophila bacteria with a clear zone of 6.5-15.0 mm, which is classified as resistant. At doses of 2000, 2500, and 3000 ppm, it did not cause death in fish for 96 hours (LD50). Hematological parameters can be a sign of the health status of fish. Tilapia given Sargassum sp. in different doses gave an effect between treatments after 30 days of rearing and post-test against A. hydrophila bacteria (p&lt;0.05). The results showed that the hematology of fish fed with Sargassum sp. extract was in the normal or healthy range. Healthy tilapia had erythrocyte counts ranging from 1.34-2.11×106 cells/mm3, hematocrit 26.17-33.19%, hemoglobin 6.26-11.2 g/dL and total leukocytes 1.01-1.50×104 cells/mm3 and total erythrocytes 5.88-9.13×104 cells/ mm3. Conclusions A dose of 3000 ppm provided the highest health improvement against A. hydrophila bacterial infection.

Genomic predictions for resistance to Aeromonas hydrophila in pacu (Piaractus mesopotamicus)

Infections caused by the bacterium Aeromonas hydrophila result in high mortality outbreaks in pacu (Piaractus mesopotamicus) production. An alternative to increase the resistance to A. hydrophila infection is the implementation of genomic selection programs, which can contribute to the sustainable development of the Brazilian aquaculture. In addition, low-density SNP panels, optimized by genotype imputation, represent a low-cost tool for implementing genomic selection on a commercial scale. This study aimed to evaluate the accuracy of genomic prediction using low (0.5 and 1 K) and medium (15 K imputed) density SNP panels; and compare breeding values accuracy with restriction-site associated DNA sequencing (18 K) and pedigree-based methods for individuals challenged for A. hydrophila. The genomic prediction analyses were conducted using genotypes from the medium-density SNP panel of pacu as reference and genotypes from a low-density SNP panel (0.5 and 1 K) using target genotype-by-sequencing technology (tGBS) for imputation. Approximately 15 K SNPs were successfully imputed with accuracy (r2) above 0.8. Time to death (TD) and binary survival (BS) against A. hydrophila infection were used as phenotypes for genomic prediction. Genomic values were estimated using the GBLUP model adopting different genotyping methods (SNP array and RAD-seq) and densities of SNPs (0.5 K, 1 K, and 15K_imputed for the array and 18 K for RAD-seq). Accuracies of genomic approaches using different methods and densities were compared to the pedigree method PBLUP to assess the benefits of incorporating genomic information. The accuracy of predicting breeding values using genomic methods outperformed the estimates obtained through PBLUP by 33%, 39%, and 67% for TD, and 36%, 39%, and 82% for BS, considering the densities of 0.5, 1, and 15K_imputed, respectively. The imputation strategy yielded better results in terms of genomic prediction accuracy for both traits. The RAD-seq genotyping method produced low-accuracy estimates (∼30% lower for both traits) compared to PBLUP, indicating that such method may not be suitable for genomic prediction of these traits. Genomic selection using genotype imputation is a viable and cost-effective approach to increase resistance to A. hydrophila infection in pacu and reduce genotyping costs without compromising genomic prediction accuracy.

Antibacterial Activity of Extract Green Seaweed Ulva intestinalis in North Waters of Aceh

The appearance of bacterial resistance and pathogenic infections makes efforts to find new drugs as natural bacterial agents continue. One of them is through the utilization of marine organisms such as seaweed. Some studies show the content of seaweed bioactive compounds has potential in the pharmacological field. This study aims to determine the type of secondary metabolite compounds and antibacterial activity of ethanol extract of Ulva intestinalis. Seaweed extraction using the maceration method for 3 x 24 hours and antibacterial activities were tested by disc diffusion method. The results showed that there were 5 types of secondary metabolite compounds in the extract, namely alkaloids, flavonoids, glycosides, saponins, and steroids. The antibacterial activity test of seaweed extract against Propionibacterium acnes and Aeromonas hydrophila bacteria in the concentration range of 50% to 100% showed a moderate inhibition zone diameter

Testing the antibacterial effectiveness of mangosteen peel extract (Garcinia mangostana L) against Aeromonas hydrophila Bacterial infection in dumbo catfish (Clarias gariepinus)

Plants belonging to the Clusiaceae species are Garcinia mangostana Linn (mangosteen fruit). The skin layer of this fruit has been used as a traditional medicine for wound healing, topical infections. Mangosteen rind contains compounds including mangostin, mangostenol, mangostinon A, mangostenon B, trapezifolixanthone, tovofillin B, alpha mangostin, beta mangostin, garsinon B, mangostanol, flavonoids, epicatechin. Gartanin, gamma mangostin, garsinon E, epicatechin. Farming African catfish (Clarias Gariepinus) when facing serious problems such as fish are susceptible to disease, mainly due to bacteria. One type of bacteria that causes the disease is Aeromonas hydrophila. This type of bacteria can cause high fish mortality in African catfish (Clarias Gariepinus) of various sizes. The purpose of this study was to determine the effect of mangosteen rind extraction on the growth of Aeromonas hydrophila bacteria in vitro, as well as the 96-hour Lethal Dose (LD50) value of mangosteen rind extract after exposure to African catfish (Clarias Gariepinus). In this study, the antibacterial activity of the material was tested in vitro with concentrations of 0%, 1.56%, 3.125%, 6.25%, 12.5%, 25% and 50%.

Effect of Guava Leaf Extract on Aeromonas Hydrophila Bacteria

Guava leaves (Psidium guajava L.) contain terpenoids, alkaloids, flavonoids, saponins and tannins, which are believed to have antibacterial properties against Aeromonas hydrophila. Aeromonas hydrophila bacteria are bacteria that are pathogenic and cause systemic disease. This research was conducted to determine the effectiveness of guava leaves in inhibiting Aeromonas hydrophil bacteria. The method used in the antibacterial activity test was the diffusion method using the paper disc technique. The results of the One-Way ANOVA test at the 5% level and followed by the Tukey test showed that the effective inhibitory concentration was 7900 ppm with a moderate antibacterial category.

Quantitative Proteomics Analysis Reveals the Effect of a MarR Family Transcriptional Regulator AHA_2124 on Aeromonas hydrophila.

The transcriptional regulators of the MarR family play an important role in diverse bacterial physiologic functions, whereas their effect and intrinsic regulatory mechanism on the aquatic pathogenic bacterium Aeromonas hydrophila are, clearly, still unknown. In this study, we firstly constructed a deletion strain of AHA_2124 (ΔAHA_2124) of a MarR family transcriptional regulator in Aeromonas hydrophila ATCC 7966 (wild type), and found that the deletion of AHA_2124 caused significantly enhanced hemolytic activity, extracellular protease activity, and motility when compared with the wild type. The differentially abundant proteins (DAPs) were compared by using data-independent acquisition (DIA), based on a quantitative proteomics technology, between the ΔAHA_2124 strain and wild type, and there were 178 DAPs including 80 proteins up-regulated and 98 proteins down-regulated. The bioinformatics analysis showed that the deletion of gene AHA_2124 led to some changes in the abundance of proteins related to multiple biological processes, such as translation, peptide transport, and oxidation and reduction. These results provided a theoretical basis for better exploring the regulatory mechanism of the MarR family transcriptional regulators of Aeromonas hydrophila on bacterial physiological functions.

High-efficiency expression of a novel antimicrobial peptide I20 with superior bactericidal ability and biocompatibility in Pichia pastoris and its efficiency enhancement to aquaculture

One of the major constraints on aquaculture is the susceptibility of farmed fish to diseases or slow growing. Antimicrobial peptide I20, as a novel feed additive, is used to cope with these limiting factors. In the current study, the Pichia pastoris expression system was used to produce I20 in large quantities, thereby reducing its application cost. In terms of molecular strategy, the I20 expression codon was optimized according to the preference of P. pastoris codon. Through traditional strategy optimization (expression strain, time, methanol concentration, temperature, and pH), the expression level of I20 in shaking bottles was 21.09 ± 1.10 mg/L. Surprisingly, the expression level of I20 in a 20 L high-cell-density cultivation was 514.78 ± 22.07 mg/L after methanol induction of 72 h. Comprehensive analyses using a series of fluorescence and microscopy revealed that I20 killed bacteria by increasing bacterial membrane permeability and binding bacterial DNA. I20 effectively killed a variety of pathogenic bacteria (Aeromonas hydrophila, Aeromonas veronii, Elizabethkingia miricola, Flavobacterium columnare, Edwardsiella ictaluri, Vibrio parahaemolyticus, Streptococcus agalactiae, Nocardia seriolae, Escherichia coli, and Staphylococcus aureus). I20 was found to have excellent biocompatibility after both feeding and injection studies. Grass carp were fed I20 diet supplemented with 200 mg/Kg I20 for 8 weeks. I20 can effectively promote intestinal villus length, secretion of digestive enzymes, and expression of growth genes to improve growth performance. I20 significantly promotes immune response to reduce tissue damage and bacterial load, enhancing survival after Aeromonas hydrophila infection. In conclusion, we systematically optimized the expression of antimicrobial peptide I20 in P. pastoris, and achieved a satisfactory efficiency for producing antimicrobial peptide I20 by integrating several strategies. The results herein showed that I20-feed promoted growth performance and disease resistance in fish, suggesting a feed supplement with great potential applications for aquaculture.

UJI AKTIVITAS ANTIBAKTERI EKSTRAK DAUN BINI SIMPUR (DILENIA SP.), KEDEBIK (MELASTOMA SP.) DAN MENGKIRAI (TREMA ORIENTALIS) TERHADAP BAKTERI AEROMONAS HYDROPHILA

Bini simpur, kedebik, and mengkirai are plants that grow a lot on Bangka Island. This plant has benefits as herbal medicine. The novelty of this research is that the Bini Simpur, Kedebik and Kirai plants can be used to treat fish infected with Aeromonas hydrophila bacteria. This research method is to use disc diffusion. The results of the phytochemical screening test proved that the leaves of Bini Simpur, Kedebik and Kirai contain flavonoids, tannins and saponins. Kedebic plants can inhibit bacteria by 12.7 mm; bini simpur 11.55 mm; and approx 10.8 mm. Conclusion Bini Simpur, Kedebik, and Kirai leaf extracts have antibacterial activity against Aeromonas hydrophila.

The Synergic Effect of Gut-Derived Probiotic Bacillus cereus SL1 And Ocimum sanctum on Growth, Intestinal Histopathology, Innate Immunity, and Expression of Enzymatic Antioxidant Genes in Fish, Cirrhinus mrigala (Hamilton, 1822).

An effective alternative approach to combat aquaculture challenges is the strategic application of bioresources, which not only mitigate disease ailment but also optimize fish growth. Hence, current research was undertaken to highlight the synergic role of bioresources such as plant immunostimulant Ocimum sanctum along with potent gut-derived probiotic Bacillus cereus strain SL1 (Gen Bank Accession Number: FJ627945.1) on mrigal (Cirrhinus mrigala) growth, antioxidant status, gut histopathology, and immune response. For 90days, fingerlings (average weight 6.8 ± 0.5g) were fed on diets having varying concentrations of O. sanctum and B. cereus. After the completion of the feeding trial, various growth, immunity, and histological and antioxidant metrics were evaluated according to standard procedures. In comparison to the control and other treatment groups, T3 group showed a significant (P < 0.05) increase in growth parameters, antioxidant enzymatic activity, and hematological and immunological parameters. In addition to it, supplementation of both B. cereus and O. sanctum also upregulated the antioxidant-related gene expressions, such as hepatic catalase gene by 1.89-3.00 folds, hepatic SOD-1 by 4.46-7.52 folds, and GPx-1of the liver by 1.56-1.95 folds. For 10days, fingerlings were challenged with the pathogenic bacterium Aeromonas hydrophila (MTCC-1739), and maximum survival rate (77.77%) was reported in fingerlings of T3 treatment. Further histopathological studies of gut tissues affirm that O. sanctum and B. cereus play a synergic role in the protection of digestive organs from the pathogenic bacterium A. hydrophila. These results suggest that O. sanctum and B. cereus synergically improved the growth performance, immunity, antioxidant status, and gut histology of C. mrigala leading to its sustainable culture.

Efektivitas Ekstrak Buah Belimbing Wuluh (Averhoa blimbi L) Dalam Menghambat Pertumbuhan Bakteri Aeromonas hydrophila Pada Ikan Mas (Cyprinus Carpio)

This research aimed to determine the optimal concentration of wuluh star fruit extract in feed as an effort to prevent the growth of Aeromonas hydrophila bacteria in common carp. The study was conducted from may to june 2023. The treatments in this study consisted of different levels of wuluh star fruit extract in the feed, comprising five (5) levels:A = 0ml wuluh star fruit extract per kg of feed + injection of Aeromonas hydrophila (positive control = PC), B = 0ml wuluh star fruit extract per kg of feed ( nrgative control – NC), C = 10ml wuluh star fruit extract per kg of feed + injection of Aeromonas hydrophila, D = 15ml wuluh star fruit extract per kg of feed + injection of Aeromonas hydrophila, and E = 20ml wuluh star fruit extract per kg of feed + injection of Aeromonas hydrophila. Each treatment had three (3) replications. The common carp used was 10 cm in size, collected from a fish farm. The fish were kept in aquariums with a stocking density of 5 fish per aquarium. Prior to treatment, the fish were acclimated to the environment for 1 week. During acclimation, the fish were fed commercial pelletswith a protein content of 36% twice a day. ANOVA analysis results showed that the addition of wuluh star fruit extract significantly influenced the growth rete and survival rate of common carp, aiding in the recovery of common carp infected with Aeromonas hydrophila BACTERIA AND PREVENTING the growth of the bacteria. The optimal concentration of wuluh star fruit extract was 15ml per kg of feed to prevent the growth of Aeromonas hydrophila bacteria.