Prophages carrying Zot toxins on different Vibrio genomes: A comprehensive assessment using multilayer networks.

Vibrios, a group of bacteria that are among the most abundant in marine environments, include several species such as Vibrio cholerae and Vibrio parahaemolyticus, which can be pathogenic to humans. Some species of Vibrio contain prophages within their genomes. These prophages can carry genes that code for toxins, such as the zonula occludens toxin (Zot), which contribute to bacterial virulence. Understanding the association between different Vibrio species, prophages and Zot genes can provide insights into their ecological interactions. In this study, we evaluated 4619 Vibrio genomes from 127 species to detect the presence of prophages carrying the Zot toxin. We found 2030 potential prophages with zot-like genes in 43 Vibrio species, showing a non-random association within a primarily modular interaction network. Some prophages, such as CTX or Vf33, were associated with specific species. In contrast, prophages phiVCY and VfO3K6 were found in 28 and 20 Vibrio species, respectively. We also identified six clusters of Zot-like sequences in prophages, with the ZOT2 cluster being the most frequent, present in 34 Vibrio species. This analysis helps to understand the distribution patterns of zot-containing prophages across Vibrio genomes and the potential routes of Zot-like toxin dissemination.

Molecular characterization, cytoprotective, DNA protective, and immunological assessment of peroxiredoxin-1 (Prdx1) from yellowtail clownfish (Amphiprion clarkii).

Peroxiredoxin-1 (Prdx1) is a thiol-specific antioxidant enzyme that detoxifies reactive oxygen species (ROS) and regulates the redox status of cells. In this study, the Prdx1 cDNA sequence was isolated from the pre-established Amphiprion clarkii (A. clarkii) (AcPrdx1) transcriptome database and characterized structurally and functionally. The AcPrdx1 coding sequence comprises 597 bp and encodes 198 amino acids with a molecular weight of 22.1 kDa and a predicted theoretical isoelectric point of 6.3. AcPrdx1 is localized and functionally available in the cytoplasm and nucleus of cells. The TXN domain of AcPrdx1 comprises two peroxiredoxin signature VCP motifs, which contain catalytic peroxidatic (Cp-C52) and resolving cysteine (CR-C173) residues. The constructed phylogenetic tree and sequence alignment revealed that AcPrdx1 is evolutionarily conserved, and its most closely related counterpart is Amphiprion ocellaris. Under normal physiological conditions, AcPrdx1 was ubiquitously detected in all tissues examined, with the most robust expression in the spleen. Furthermore, AcPrdx1 transcripts were significantly upregulated in the spleen, head kidney, and blood after immune stimulation by polyinosinic:polycytidylic acid (poly (I:C)), lipopolysaccharide (LPS), and Vibrio harveyi injection. Recombinant AcPrdx1 (rAcPrdx1) demonstrated antioxidant and DNA protective properties in a concentration-dependent manner, as evidenced by insulin disulfide reduction, peroxidase activity, and metal-catalyzed oxidation (MCO) assays, whereas cells transfected with pcDNA3.1(+)/AcPrdx1 showed significant cytoprotective function under oxidative and nitrosative stress. Overexpression of AcPrdx1 in fathead minnow (FHM) cells led to a lower viral copy number following viral hemorrhagic septicemia virus (VHSV) infection, along with upregulation of several antiviral genes. Collectively, this study provides insights into the function of AcPrdx1 in defense against oxidative stressors and its role in the immune response against pathogenic infections in A. clarkii.

AMR Threat Perception Assessment of Heterotrophic Bacteria From Shrimp Aquaculture Through Epidemiological Cut off Values.

BACKGROUND: Emergence and dissemination of antibiotic resistance is one of the major risks associated with the rampant usage of antibiotics in food-producing animals including aquaculture. OBJECTIVE: To determine Epidemiological Cut-OFF (ECOFF) values of heterotrophic bacterial populations from shrimp culture environments against five different antibiotics. METHODS: In this present study, bacterial samples were isolated from Penaeus vannamei culture environment in different locations of Andhra Pradesh, which is the aquaculture hub of India. The bacterial isolates were assessed for antibiotic resistance towards five antibiotics belonging to different classes (oxytetracycline, chloramphenicol, erythromycin, ciprofloxacin, and co-trimoxazole) by the disc diffusion method. Determination of Epidemiological Cut-OFF (ECOFF) values and analysis by employing normalized resistance interpretation (NRI) was carried out. RESULTS: The most dominant bacterial populations from shrimp culture were Vibrio spp. (pathogenic bacteria) followed by Bacillus spp. (probiotic bacteria). The bacterial isolates showed highest resistance towards oxytetracycline (overall 23.38%) and in location L6 (59.4%) followed by co-trimoxazole (31.1%). ECOFF values calculated by employing NRI showed that the disc diffusion data were distributed in a normalized manner. The maximum ECOFF value was obtained for ciprofloxacin (23.32 mm), while the minimum value was observed for oxytetracycline (9.05 mm). The antibiotic resistant phenotypes showed that the majority of the heterotrophic bacterial isolates (>60%) belonged to the non-wild type phenotype and primarily towards oxytetracycline (90%). CONCLUSION: The presence of non-wild antibiotic-resistant phenotypes of heterotrophic bacterial populations (which include not only pathogenic bacteria but also probiotic bacteria) indicates that shrimp culture ponds may be a reservoir for drug-resistant bacteria and there is a greater risk associated with transmission of resistant genes across bacterial flora. HIGHLIGHTS: NRI analysis of antibiotic disc diffusion data of heterotrophic bacterial populations in shrimp aquaculture environments revealed that majority of them belonged to non-wild type (90%) paticularly to oxytetracycline in comparison to other studied antibiotics (chloramphenicol, erythromycin, ciprofloxacin and co-trimoxazole).

High sensitivity and low-cost flavin luciferase (FLUXVc)-based reporter gene for mammalian cell expression.

Luciferase-based gene reporters generating bioluminescence signals are important tools for biomedical research. Amongst the luciferases, flavin-dependent enzymes use the most economical chemicals. However, their applications in mammalian cells are limited due to their low signals compared to other systems. Here, we constructed Flavin Luciferase from Vibrio campbellii (Vc) for Mammalian Cell Expression (FLUXVc) by engineering luciferase from V. campbellii (the most thermostable bacterial luciferase reported to date) and optimizing its expression and reporter assays in mammalian cells which can improve the bioluminescence light output by >400-fold as compared to the nonengineered version. We found that the FLUXVc reporter gene can be overexpressed in various cell lines and showed outstanding signal-to-background in HepG2 cells, significantly higher than that of firefly luciferase (Fluc). The combined use of FLUXVc/Fluc as target/control vectors gave the most stable signals, better than the standard set of Fluc(target)/Rluc(control). We also demonstrated that FLUXVc can be used for testing inhibitors of the NF-κB signaling pathway. Collectively, our results provide an optimized method for using the more economical flavin-dependent luciferase in mammalian cells.

Virulence and antimicrobial resistance characteristics assessment of Vibrio isolated from shrimp (Penaeus vannamei) breeding system in south China.

The diseases caused by Vibrio during shrimp breeding program have the risk of spreading in different aquatic areas through larvae transportation between different regions. Therefore, the population distribution and the virulence and antibiotic resistance risk of 5 pathogenic Vibrio in shrimp (Penaeus vannamei) breeding system in China were evaluated for the first time. A total of 418 isolates were recovered from shrimp, breeding water and biological baits samples, and 312 isolates were identified as Vibrio genus based on 16s rDNA, among which V. alginolyticus, V. harveyi, V. parahaemolyticus, V. cholerae and V. campbellii were the dominant species. And 10/20 kinds of virulence genes (chiA, luxR, vhh, tlh, chxA, sepro, flaA, vch, VAC and rpoS) were detected among the 5 Vibrio species. Multiple antibiotic resistance (MAR) index of the 5 dominant Vibrio isolates were 0.13-0.88 %, and 36.5 % isolates with MAR < 0.2. But the antibiotic resistance pattern abundance (ARPA) index ranged from 0.25 to 0.56, which indicated the antibiotic phenotypes of Vibrio species in the shrimp breeding system in China were homogeneity. Furthermore, resistance quotients (RQs) calculation results displayed that the dominant Vibrio species in the shrimp breeding system in China showed no or low selection pressure for resistance to cefoperazone/sulbactam, enrofloxacin, ciprofloxacin, fluoroquine, florfenicol, tetracycline and doxycycline. But only 5 resistance genes were detected, which were strA (43.8 %), strB (11.7 %), QnrVC (2.9 %), sul2 (8.8 %) and Int4 (8.8 %), respectively, and the antimicrobial resistance genotypes were not previously correlated with their phenotypes. The relevant research results provide theoretical basis for epizootic tracking in aquatic system in China, and targeting its final risk in aquatic ecosystem and public health perspectives.

Vibrio natriegens genome-scale modeling reveals insights into halophilic adaptations and resource allocation.

Vibrio natriegens is a Gram-negative bacterium with an exceptional growth rate that has the potential to become a standard biotechnological host for laboratory and industrial bioproduction. Despite this burgeoning interest, the current lack of organism-specific qualitative and quantitative computational tools has hampered the community's ability to rationally engineer this bacterium. In this study, we present the first genome-scale metabolic model (GSMM) of V. natriegens. The GSMM (iLC858) was developed using an automated draft assembly and extensive manual curation and was validated by comparing predicted yields, central metabolic fluxes, viable carbon substrates, and essential genes with empirical data. Mass spectrometry-based proteomics data confirmed the translation of at least 76% of the enzyme-encoding genes predicted to be expressed by the model during aerobic growth in a minimal medium. iLC858 was subsequently used to carry out a metabolic comparison between the model organism Escherichia coli and V. natriegens, leading to an analysis of the model architecture of V. natriegens' respiratory and ATP-generating system and the discovery of a role for a sodium-dependent oxaloacetate decarboxylase pump. The proteomics data were further used to investigate additional halophilic adaptations of V. natriegens. Finally, iLC858 was utilized to create a Resource Balance Analysis model to study the allocation of carbon resources. Taken together, the models presented provide useful computational tools to guide metabolic engineering efforts in V. natriegens.

Complete genome of Vibrio japonicus strain JCM 31412 T and assessment of the Nereis clade of the genus Vibrio.

Clade-based taxonomy has become a recognised means of classifying members of the family Vibrionaceae. A multilocus sequence analysis (MLSA) approach based on eight housekeeping genes can be used to infer phylogenetic relationships, which then groups species into monophyletic clades. Recent work on the Vibrionaceae clades added newly described species and updated existing relationships; the Nereis clade currently includes Vibrio nereis and Vibrio hepatarius. A publication characterising Vibrio japonicus as a novel species placed it within the Nereis clade, but this strain was not included in a recently published taxonomic update because a genome sequence was not available for phylogenetic assessment. To resolve this discrepancy and assess the taxonomic position of V. japonicus within the updated clades, we sequenced the complete genome of V. japonicus JCM 31412 T and conducted phylogenetic and genomic analyses of this clade. Vibrio japonicus remains within the Nereis clade and phylogenomic, average nucleotide identity (ANI), and average amino acid identity (AAI) analyses confirm this relationship. Additional genomic assessments on all Nereis clade members found gene clusters and inferred functionalities shared among the species. This work represents the first complete genome of a member of the Nereis clade and updates the clade-based taxonomy of the Vibrionaceae family.

Clinical and Epidemiologic Characteristics and Therapeutic Management of Patients with Vibrio Infections, Bay of Biscay, France, 2001-2019.

Noncholera vibriosis is a rare, opportunistic bacterial infection caused by Vibrio spp. other than V. cholerae O1/O139 and diagnosed mainly during the hot summer months in patients after seaside activities. Detailed knowledge of circulating pathogenic strains and heterogeneities in infection outcomes and disease dynamics may help in patient management. We conducted a multicenter case-series study documenting Vibrio infections in 67 patients from 8 hospitals in the Bay of Biscay, France, over a 19-year period. Infections were mainly caused by V. alginolyticus (34%), V. parahaemolyticus (30%), non-O1/O139 V. cholerae (15%), and V. vulnificus (10%). Drug-susceptibility testing revealed intermediate and resistant strains to penicillins and first-generation cephalosporins. The acute infections (e.g., those involving digestive disorder, cellulitis, osteitis, pneumonia, and endocarditis) led to a life-threatening event (septic shock), amputation, or death in 36% of patients. Physicians may need to add vibriosis to their list of infections to assess in patients with associated risk factors.

Microbiological assessment of marine and estuarine ecosystems using fecal indicator bacteria, Salmonella, Vibrio and antibiotic resistance pattern.

Marine and estuarine environments are often affected by microbiological contamination that adversely affects their use and severely impacts human health. To examine the influence of anthropogenic activities, this study used two different ecosystems in Agadir Bay, to compare fecal indicator bacteria (FIB) and bacterial pathogen profiles over two years. Vibrio target pathogens were detected at a high frequency (49.3%), while a low percentage (5.5%) was noted for Salmonella. Apart from those mentioned above, several other pathogenic bacteria were detected such as Cronobacter sakzakii, Pseudomonas fluorescens, and Aeromonas hydrophila. We also investigated the antimicrobial resistance of the pathogenic bacteria isolated. Salmonella strains were sensitive to all the antibiotics used, except ampicillin, amoxicillin + Ac clavulanic and chloramphenicol. And Vibrio strains were resistant to ampicillin, cephalothin, amikacin, and ciprofloxacin. This study highlights the limitations of FIB in assessing the microbiological quality and the importance of environmental surveys in understanding the distribution of pathogens.

Detection of Zoonotic Bacteria and Paragonimus kellicotti in Red Swamp Crayfish (Procambarus clarkii) and the Assessment of Traditional Crayfish Boils.

ABSTRACT: Studies of red swamp crayfish (Procambarus clarkii) outside of the United States confirm the presence of a variety of zoonotic pathogens, but it is unknown whether these same pathogens occur in P. clarkii in the United States. The U.S. commercial crayfish industry generates $200 million yearly, underscoring the need to evaluate this consumer commodity. The study objectives were to evaluate specific zoonotic pathogens present on P. clarkii from Alabama and Louisiana, states in the southeastern United States, and to determine the effectiveness of traditional food preparation methods to reduce pathogens. Experiment A evaluated the presence of Escherichia coli, Salmonella, Staphylococcus aureus, and Vibrio spp. in crayfish and environmental samples over a 2-month collection period (May to June 2021). Crayfish sampling consisted of swabbing the cephalothorax region; 15 samples were tested for E. coli, Salmonella, and S. aureus, and an additional 15 samples for Vibrio spp. Additionally, crayfish shipping materials were sampled. In experiment B, 92 crayfish were evaluated for Paragonimus kellicotti. Experiment C compared live and boiled crayfish for the presence of Vibrio spp. In experiments A and B, all 60 (100%) crayfish samples and 13 (81.25%) of 16 environmental samples showed growth characteristic of Vibrio spp. Three (5%) of 60 samples showed E. coli growth, with no statistical difference (P = 0.5536) between farms. P. kellicotti, Salmonella, and S. aureus were not recovered from any samples. In experiment C, all 10 (100%) of the live preboiled crayfish samples showed characteristic growth, whereas 1 (10%) of 10 samples of crayfish boiled in unseasoned water showed Vibrio growth (P < 0.0001). These results confirm that Vibrio spp. and E. coli may be present on U.S. commercial crayfish and that care should be taken when handling any materials that come into contact with live crayfish because they can potentially be contaminated.

Transcriptome profiling based on larvae at different time points after hatching provides a core set of gene resource for understanding the immune response mechanisms of the egg-protecting behavior against Vibrio anguillarum infection in Amphioctopus fangsiao.

Mollusks have recently received increasing attention because of their unique immune systems. Mollusks such as Amphioctopus fangsiao are economically important cephalopods, and the effects of their egg-protecting behavior on the larval immune response are unclear. Meanwhile, little research has been done on the resistance response of cephalopod larvae infected with pathogenic bacteria such as Vibrio anguillarum. In this study, V. anguillarum was used to infect the primary hatching A. fangsiao larvae under different egg-protecting behaviors for 24 h, and a total of 7156 differentially expressed genes (DEGs) were identified at four time points after hatching based on transcriptome analysis. GO and KEGG enrichment analyses showed that multiple immune-related GO terms and KEGG signaling pathways were enriched. Protein-protein interaction networks (PPI networks) were used to search functional relationships between immune-related DEGs. Finally, 20 hub genes related to multiple gene functions or involved in multiple signaling pathways were identified, and their accuracy was verified using quantitative RT-PCR. PPI networks were first used to study the effects A. fangsiao larvae after infection with V. anguillarum under different egg-protecting behaviors. The results provide significant genetic resources for exploring invertebrate larval immune processes. The data lays a foundation for further study the immune response mechanisms for invertebrates after infection.

An Integrative, Multiparametric Approach for the Comprehensive Assessment of Microbial Quality and Pollution in Aquaculture Systems.

As the aquaculture sector significantly expanded worldwide in the past decades, the concept of sustainable aquaculture has developed with the challenge of not only maximizing benefits but also minimizing the negative impacts on the environment assuring, at the same time, food security. In this framework, monitoring and improving the microbiological water quality and animal health are a central topic. In the present study, we evaluated the seawater microbiological quality in a mariculture system located in a Mediterranean coastal area (Northern Ionian Sea, Italy). We furnished, for the first time, a microbial inventory based on conventional culture-based methods, integrated with the 16S rRNA gene metabarcoding approach for vibrios identification and diversity analyses, and further implemented with microbial metabolic profiling data obtained from the Biolog EcoPlate system. Microbiological pollution indicators, vibrios diversity, and microbial metabolism were determined in two different times of the year (July and December). All microbial parameters measured in July were markedly increased compared to those measured in December. The presence of potentially pathogenic vibrios is discussed concerning the risk of fish disease and human infections. Thus, the microbial inventory here proposed might represent a new multiparametric approach for the suitable surveillance of the microbial quality in a mariculture system. Consequently, it could be useful for ensuring the safety of both the reared species and the consumers in the light of sustainable, eco-friendly aquaculture management.

Assessment of bacteriophage vB_Pd_PDCC-1 on bacterial dynamics during ontogenetic development of the longfin yellowtail (Seriola rivoliana).

The Seriola genus includes species of worldwide commercial importance due to its rapid growth and easy adaptability to confinement conditions. However, like other fish species, large mortalities occur during their early life stages, where the main problems are caused by opportunistic bacteria. Disease control strategies are thus urgently needed. The present study aimed to evaluate the efficacy of phage vB_Pd_PDCC-1 during the early development of longfin yellowtail (Seriola rivoliana), as well as its effect on microbial communities. This broad-host-range phage was added to the culture every 3 days starting from the egg-stage until 12 days after hatching (DAH) at a concentration of 1.41×1010 plaque-forming units (PFU) per mL and at a multiplicity of infection (MOI) of 1. The results showed positive effects (p<0.05) on egg hatching, survival, growth, and pigmentation area in treated larvae. Moreover, high-throughput sequencing analysis of 16S rRNA genes showed that phage administration did not produce significant changes (p>0.05) in the composition and structure of the associated microbiota. However, sequences affiliated to the Gammaproteobacteria class were displaced by those belonging to the Alphaproteobacteria class over time regardless of the treatment received. At the family level, there was a decrease in Rhodobacteraceae, Pseudoalteromonadaceae, and Flavobacteriaceae in both groups over time. To our best knowledge, this study represents the first attempt to evaluate the effect of a phage as a biological control agent during ontogenetic development of longfin yellowtail larvae. KEY POINTS: • Phages can be used against proliferation of Vibrio in fish cultures. • Seriola includes several important commercial fish species due to its rapid growth. • Phages do not cause significant changes in the associated microbiota.

Assessment of predominant bacteria in noble pen shell (Pinna nobilis) collected in the Eastern Adriatic Sea.

Noble pen shell (Pinna nobilis) is an endemic species and the largest known bivalve in the Mediterranean Sea. By filtering large amounts of water, they maintain a high percentage of organic matter, hence playing an important role in the marine ecosystem. The ecological community of pen shells is impressive, and there are numerous microorganisms present in its soft tissues. Since this species is highly endangered due to recently described mass mortalities throughout the Mediterranean, this study was aimed at finding out more about its microbiome. In this study, we identified the predominant bacterial populations of specimens collected at three separate locations along the Eastern Adriatic coast. The predominant bacteria were isolated and 16S rRNA sequencing was performed to identify eight different bacterial genera: Aestuariibacter sp., Aliivibrio sp., Alteromonas sp., Marinobacter sp., Pseudoalteromonas sp., Rubritalea sp., Thalassospira sp. and the Vibrio splendidus clade. The identified genera are ubiquitous in the marine environment and have previously been described as both beneficial symbionts and potential pathogens in other molluscs. There was a clear difference in the predominant bacterial populations between northern and southern sampling sites, which could be linked to water temperature. These findings indicate the need for expanded sampling over a longer time period, since more exhaustive research would provide information vital to the conservation of this critically endangered species.

A strategy for an initial assessment of the ecotoxicological effects of transformation products of pesticides in aquatic systems following a tiered approach.

In order to conduct a fast and comprehensive toxicity screening of pesticide transformation products (TPs), this study used a tiered approach by a combination of in silico and experimental methods to determine the probability to be of relevance for risk assessment. The six pesticides Boscalid, Penconazole, Diuron, Terbutryn, Octhilinone (OIT), and Mecoprop were used as model compounds. Identification of corresponding environmental known and unknown TPs were done by literature analysis and photolysis experiments in combination. Aquatic solutions of the pesticides were photolysed to generate TPs which can be expected in the aquatic environment. The resulting mixtures were screened for TPs by high resolution LC-MS/MS. The herein developed approach was conducted at three different tiers: Literature review and in silico methods were used to predict exemplary the environmental bacterial toxicity and the genotoxicity of every single TP at tier I. In case of indications to be toxic, experiments at tier II were applied. Hereby, the photolytic mixtures containing parent compound and TPs were used for the consecutive toxicity test. Microtox assay for the parent compounds and the photolytic mixture was conducted to determine the acute and chronic toxicity and the growth inhibition of V. fischeri. Umu-tests were conducted to determine primary DNA damage. At tier III, single substance standards were used to conduct toxicity tests in case of toxic indication by previous tiers and availability of analytical standard. Identification of TPs revealed 45 known environmental TPs that originated from the six pesticides. The number of substances that need to be assessed was therefore more than sevenfold. By the tiered approach, it was possible to assess toxicological effects on environmental bacteria of 94% of the selected TPs. For 20% we found strong evidence to be toxic to environmental bacteria, as they were assessed at least at two tiers. For further 44% of the TPs we found slight evidence, as they could be assessed at one tier. Contrary, this approach turned out to be unsuitable to assess genotoxic effects of TPs neither by in silico tools nor by experiments. The number of substances that could probably pose a risk onto environment was quadrupled in comparison to the consideration of solely the parent compounds. Thus, this study demonstrates that the conducted screening approach allows for easy and fast identification of environmental relevant TPs. However, the study presented was a very first screening. Its applicability domain needs to be assessed further. For this purpose as a very next step the approach suggested here should be verified by applying additional endpoints and including additional parent compounds.

Diagnóstico de la calidad físico química y biológica del agua en el Golfo de Fonseca, La Unión, El Salvador. Propuestas para el desarrollo sostenible: en asocio con el Centro de Educación e Instrucción Naval de El Salvador, CEIN-Base Naval de La Unión / Diagnosis of the physical, chemical and biological quality of water in the Gulf of Fonseca, La Unión, El Salvador. Proposals for sustainable development: in association with the Naval Education and Training Center of El Salvador, CEIN-La Unión Naval Base

Este estudio permitió conocer la calidad microbiológica del agua del Golfo de Fonseca, a través de un programa de monitoreo realizado durante 12 meses, en 9 puntos de muestreo distribuidos en 3 sectores. "A" estero La Manzanilla-Isla Perico, "B" Ciudad de La Unión ­ bocana río Goascorán y "C" estero El Tamarindo ­ Isla Meanguera. El propósito fue obtener registros de contaminación de aguas costeras para el país y el impacto que las aguas residuales producen en el ambiente costero y la pérdida de la calidad del agua para actividades tales como la maricultura y la recreación. Entre las bacterias encontradas se encuentran: Enterococcus, Pseudomonas, Vibrios y Heterótrofas. Dichas bacterias están asociadas con diferentes enfermedades para la salud humana, tal es el caso de las pseudomonas, las cuales están frecuentemente asociadas a infecciones de los tractos respiratorio y urinario. Los resultados obtenidos de Vibrio indican que el agua no es apta para uso en acuicultura, ni para uso recreativo, el agua se encuentra en el límite de referencia en cuanto al uso con propósito de producción acuícola y límite de referencia en cuanto al riesgo de consumo de productos pesqueros.

This study allowed to know the microbiological quality of the water of Golfo de Fonseca, through a monitoring program carried out during 12 months, in 9 sampling points distributed in 3 sectors. "A" La Manzanilla estuary- Isla Perico, "B" City of La Unión - Río Goascorán mouth and "C" El Tamarindo estuary - Isla Meanguera. The purpose was to obtain records of coastal water pollution for the country and the impact that wastewater produces on the coastal environment and the loss of water quality for activities such as mariculture and recreation. Among the bacteria found are: Enterococcus, Pseudomonas, Vibrios and Heterotrophs. These bacteria are associated with different diseases for human health, such is the case of pseudomonas, which are frequently associated with infections of the respiratory and urinary tracts. The results obtained from Vibrio indicate that the water is not suitable for use in aquaculture, nor for recreational use, the water is at the reference limit in terms of use for the purpose of aquaculture production and the reference limit regarding the risk of consumption. of fishery products.

Chlorination and bromination of 1,3-diphenylguanidine and 1,3-di-o-tolylguanidine: Kinetics, transformation products and toxicity assessment.

This works investigates the chlorination and bromination of two rubber and polymer related chemicals, which have emerged as relevant water contaminants, i.e. 1,3-di-o-tolylguanidine (DTG) and 1,3-diphenylguanidine (DPG). Kinetic constants at different pH values were obtained and modelled, taking into account the pKa values of DTG/DPG and HClO, showing that the maximum reaction rate (kapp > 104 M-1 s-1) is obtained at pH values 8.8 for DPG and 9.1 for DTG. Bromination is also very fast, although unlike chlorination, deviation from the model was observed at neutral pH, which was attributed to formation of metastable transformation product (TP). A total of 35 TPs, corresponding to halogenation, hydroxylation, formation of monophenylguanidine derivatives and cyclization reactions, were tentatively identified. Furthermore it was found that chloroform can be formed up to a 25% molar yield, while dichloroacetonitrile was formed into less than a 3% yield. Several ecotoxicological endpoints were predicted by quantitative structure-activity relationship models (QSAR) for the TPs, some of which were predicted to be more toxic than DPG/DTG. Also a chlorinated solution investigated by a Vibrio Fisheri acute toxicity test, confirmed that toxicity increases with chlorination.

Characterization and assessment of barnacle larval settlement-inducing activity of extracellular polymeric substances isolated from marine biofilm bacteria.

Extracellular polymeric substances (EPSs) are the hydrated gelatinous matrix produced by microorganisms for attachment in a biofilm environment. In this study, the compositional variation between EPSs of three marine biofilm bacteria (Pseudoalteromonas shioyasakiensis, Vibrio harveyi and Planomicrobium sp.) were analysed by GC-MS, 1H NMR, FT-IR and XRD and SEM. The ecological significance of exopolymers was assessed in vivo using marine model organism barnacle larvae for their settlement-inducing activity. Chemical analysis revealed the presence of glycan fucosylated oligosaccharides, tetraose, trisaccharides, iso-B-Pentasaccharides, sialyllactose, oligomannose, galacto-N-biose, difucosyl-para-lacto-N-neohexaose, 3'-sialyl N-acetyllactosamine and isoglobotriaose-ß-N(Acetyl)-Propargyl in all extracted EPSs. Bioassay results indicated that treatment of the barnacle larvae with EPSs from three bacterial strains enhanced settlement on substrates. In conclusion, this study highlighted the role of water-soluble EPSs in the invertebrate larval settlement on artificial materials.

Efficacy assessment of commercially available natural products and antibiotics, commonly used for mitigation of pathogenic Vibrio outbreaks in Ecuadorian Penaeus (Litopenaeus) vannamei hatcheries.

Bacterial diseases cause high mortality in Penaeus (Litopenaeus) vannamei postlarvae. Therefore, appropriate application of efficient therapeutic products is of vital importance for disease control. This study evaluated through in vitro analyses the antimicrobial effectiveness of commercial therapeutic products used for P. vannamei bacterial diseases and antibiotics against pathogenic Vibrio strains circulating in Ecuadorian hatcheries. Twenty strains were isolated from 31 larvae samples with high bacterial counts from 10 hatcheries collected during mortality events. The strains virulence was verified through challenge tests with Artemia franciscana nauplii and P. vannamei postlarvae. Through 16S rRNA sequence analysis, strains showed a great similarity to the Vibrio sequences reported as pathogens, with 95% belonging to the Harveyi clade. Through antibiograms and minimal inhibitory concentration (MIC) in vitro tests we found that furazolidone, ciprofloxacin, chloramphenicol, norfloxacin, nalidixic acid, florfenicol, fosfomycin and enrofloxacin inhibited the growth of all or most of the strains. Less efficient antibiotics were penicillin, oxytetracycline and tetracycline. A multiple antibiotic resistance (MAR) index of 0.23 showed some level of resistance to antibiotics, with two MAR prevalent patterns (Penicillin-Oxytetracycline and Penicillin-Oxytetracycline-Tetracycline). From a total of 16 natural products (five probiotics, nine organic acids and two essential oils), only three (one probiotic, one organic acid and one essential oil) were effective to control most of the strains. Shrimp producers can apply relatively simple in vitro analyses, such as those employed in this study, to help take adequate management decisions to reduce the impact of bacterial diseases and increase profit.

Ecotoxicity assessment of boreal lake sediments affected by metal mining: Sediment quality triad approach complemented with metal bioavailability and body residue studies.

There are several methods for studying metal-contaminated freshwater sediments, but more information is needed on which methods to include in ecological risk assessment. In this study, we compliment the traditional Sediment Quality Triad (SQT) approach - including information on chemistry, toxicity and ecological status - with studies on metal bioavailability and metal body residues in local organisms. We studied four mining-affected boreal lakes in Finland by conducting chemical analyses of sediment and water, toxicity tests (L. variegatus, V. fischeri, C. riparius, L. stagnalis), and analysis of benthic organism community structure. In addition, we studied the relationships between metal loading, toxicity, metal bioavailability, and metal body residues in the field-collected biota. Chemistry and benthic organism community structures show adverse effects in those lakes, where the metal concentrations are the highest. However, toxicity was connected to low sediment pH during the experiment, rather than to high metal concentrations. Toxicity was observed in 4 out of 6 toxicity tests including growth test with L. variegatus, bulk sediment test with V. fischeri, and the L. stagnalis toxicity test. The C. riparius test did not show toxicity. Metal body residues in biota were not high enough to induce adverse effects (0.1-4.1 mg Cu/kg fw, 0.01-0.3 mg Ni/kg fw, 2.9-26.7 mg Zn/kg fw and 0.01-0.7 mg As/kg fw). Chemical analyses, metal bioavailability assessment and benthic community structures survey revealed adverse effects in the sediments, where metal concentrations are highest (Lake SJ and Lake KS). Standard toxicity tests were not suitable for studying acid, sulfide-rich sediments and, therefore, benthic structure study and chemical analyses are believed to give more reliable results of the ecological status of these sediments.