Marine Water Samples Research Articles

INVESTIGATION OF N-ACYL HOMOSERINE LACTONE-BASED QUORUM-SENSING SYSTEM AND ALIGINATE LYASE ACTIVITY IN MARINE BACTERIAL SPECIES OF GRIMONTIA MARINA AS01 AND ALTEROMONAS MACLEODII AS02

Production, detection, and reaction to external signaling molecules are essential steps in quorum sensing (QS) process. Through the use of QS, bacterial communities may synchronize their responses to shifts in the density and diversity of their vicinal neighbors. QS also play an important role in regulating enzmyatic activities among marine bacteria. The aim of the present study was to detect and identify N- acyl homoserine lactones (AHLs) based QS signaling molecules and the possible influence on alginate lyase in marine bacterial isolates of Grimontia marina AS01 and Alteromonas macleodi AS02. Marine water samples were collected from Arabian Sea, Karchi Pakistan, following the standard collection methods. Bacterial strains were isolated and pure cultured using Zobell 2216 marine medium. Molecular identification was achieved based on 16S rRNA gene analysis. Screening for AHLs was achieved using Agrobacterium tumefaciens A136 as a biosensor. Based on 16S rRNA analysis, the bacterial strains were identified as Grimontia marina strain AS01 (OP143768) and Alteromonas macleodii strain AS02 (OP143769). Cross-feeding bioassay revealed the positive reactions for the production of AHLs. Reversed phase-TLC analysis showed the identification of C6-HSL produced by G. marina AS01 and 3OXO-C6-HSL by A. macleodii AS02 strain. Moreover, QS inhibitor AiiA protein reduced the production of alginate lyase in A. macleodi AS02, while no effect was observed in G. marina AS01. These results substantiate the involvement of QS system in regulating alginate lyase activity in A. macleodii AS02. QS in marine bacteria may involve in hydrolysis of complex organic matter in marine environment.

Playing “hide and seek” with the Mediterranean monk seal: a citizen science dataset reveals its distribution from molecular traces (eDNA)

Animal conservation relies on assessing the distribution and habitat use of species, but for endangered/elusive animals this can prove difficult. The Monk Seal, Monachus monachus, is one of the world's most endangered species of pinniped, and the only one endemic to the Mediterranean Sea. During recent decades, direct observations have been few and scattered, making it difficult to determine its distribution away from the Aegean Sea (core distribution area of the post-decline relict population). This study relies on environmental DNA (eDNA) analysis to detect the presence of the Monk Seal in 135 samples collected in 120 locations of the central/western Mediterranean Sea, spanning about 1500 km longitudinally and 1000 km latitudinally. A recently described species-specific qPCR assay was used on marine-water samples, mostly collected during 2021 by a Citizen Science (CS) project. Positive detections occurred throughout the longitudinal range, including the westernmost surveyed area (Balearic archipelago). The distribution of the positive detections indicated six “hotspots”, mostly overlapping with historical Monk Seal sites, suggesting that habitat-specific characteristics play a fundamental role. We applied single-season occupancy models to correct for detection probability and to assess the importance of site-specific characteristics. The distance from small islets and protected (or access-restricted) areas was correlated negatively with the detection probability. This novel molecular approach, applied here for the first time in an extensive CS study, proved its potential as a tool for monitoring the distribution of this endangered/elusive species.

A novel promising laccase from the psychrotolerant and halotolerant Antarctic marine Halomonas sp. M68 strain.

Microbial communities inhabiting the Antarctic Ocean show psychrophilic and halophilic adaptations conferring interesting properties to the enzymes they produce, which could be exploited in biotechnology and bioremediation processes. Use of cold- and salt-tolerant enzymes allows to limit costs, reduce contaminations, and minimize pretreatment steps. Here, we report on the screening of 186 morphologically diverse microorganisms isolated from marine biofilms and water samples collected in Terra Nova Bay (Ross Sea, Antarctica) for the identification of new laccase activities. After primary screening, 13.4 and 10.8% of the isolates were identified for the ability to oxidize 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and the dye azure B, respectively. Amongst them, the marine Halomonas sp. strain M68 showed the highest activity. Production of its laccase-like activity increased six-fold when copper was added to culture medium. Enzymatic activity-guided separation coupled with mass spectrometry identified this intracellular laccase-like protein (named Ant laccase) as belonging to the copper resistance system multicopper oxidase family. Ant laccase oxidized ABTS and 2,6-dimethoxy phenol, working better at acidic pHs The enzyme showed a good thermostability, with optimal temperature in the 40-50°C range and maintaining more than 40% of its maximal activity even at 10°C. Furthermore, Ant laccase was salt- and organic solvent-tolerant, paving the way for its use in harsh conditions. To our knowledge, this is the first report concerning the characterization of a thermo- and halo-tolerant laccase isolated from a marine Antarctic bacterium.

Improvement of Advanced Sample Preparation Systems for the Determination of Trace Ni in Seawater by Electro-Membranes.

Due to its important environmental role, the analysis of trace metals in natural waters is attracting increasing attention; consequently, faster and more accurate analytical methods are now needed to reach even lower limits of detection. In this work, we propose the use of electro-membrane extraction (EME) to improve analytical methods based on hollow fiber liquid phase micro-extraction (HFLPME). Specifically, an EME-based method for the determination of trace Ni in seawater has been developed, using an HFLPME system with di-2-ethylhexyl phosphoric acid (DEHPA) in kerosene as a chemical carrier, followed by instrumental determination by graphite furnace atomic absorption spectroscopy (GFAAS). Under optimum conditions, Ni was pre-concentrated 180 ± 17 times after 15 min, using sample pH = 5.5, the concentration of DEHPA 0.9 M in the liquid membranes, and 1.9 M HNO3 in the acceptor solution, as well as an electric potential of 25 V with the sample being stirred at 500 rpm. When compared with other HFLPME systems for pre-concentration of trace Ni in seawater in the absence of electric potential, the enrichment factor was improved 2.2 times, while the time of extraction was reduced an 89%. The limit of detection of the new method was 23.3 ng L-1, and both its applicability and accuracy were successfully evaluated by analyzing Ni concentration in a seawater-certified reference material (BCR-403), showing the reliability of EME for sample preparation in the determination of trace metals in marine water samples.

In vitro antifungal activity of the extracts of selected marine microalgae against human pathogens

The present study was designed to screen the biological activities of marine micro algal samples collected along the South Indian coastal belt. For that the marine water samples were collected from different coastal locations such as Colachel, Kadiapattinam and Muttom of Kanyakumari District, South India. The collected sea water sample were filtered, serially diluted, supplemented with Walne's medium and subjected to light incubation under laboratory conditions for two weeks for optimum growth and the algal species were identified and isolated based on their morphological characteristics with the help of light microscope. Totally 10 isolates, 5 from Muttom seawater collection, 3 from Kadiapattinam and 2 from Colachel collections were identified. 5 isolates from the Muttom seawater collection was evaluated further. In this evaluation, the growth pattern of isolated algal species was studied and their mass production was done. The cultured algal species were subjected to centrifugal separation and solvent extraction by using three solvents such as ethyl acetate, methanol and water. The supernatants collected were evaluated for the antimicrobial activity against three fungal pathogens viz., Aspergillus niger, Candida albicans and Mucur sp. In the antimicrobial evaluation, the methanol extract of S–2, S–3, S–4 and S–5 samples showed a significant antimicrobial activity against the tested fungal culture. Our further studies directed toward the identification algal species, phytochemical screening and various detailed pharmacological screening may give more valuable results.

Assessing good environmental status through mesozooplankton biodiversity: a step forward.

We developed a zooplankton-based water-quality evaluating method using indices of alpha diversity. Two key objectives were set: (i) the comparison of two-different quality-samples from different areas, and the verification of their differentiation, based on mesozooplankton biodiversity indices; and (ii) the development of a methodology, which was able to assess the quality of new marine water samples. Our analysis was based on a 24-year-long in situ dataset (1987-2010) of 139 samples in which 86 mesozooplankton taxa were identified. High-diversity and high evenness values were reported in the case of the "good" status sample, while low diversity, low evenness and high dominance values occurred at the lower quality one. A linear discriminant analysis (LDA) was conducted that discriminated the tested samples at 100%. This LDA was then used to evaluate samples of unknown quality. Finally, 90% of them were classified with a probability of correct classification (posterior probability) >95%. The present study proves that mesozooplankton diversity indices can discriminate different levels of anthropogenic impacts. In this sense, it can be used as a reliable indicator for environmental assessment in the pelagic habitats of the Mediterranean Sea.

Bioprospecting of tropical microalgae for high-value products: n-3 polyunsaturated fatty acids and carotenoids

Microalgae are an important renewable source of carotenoids and polyunsaturated fatty acids (PUFAs), with strong antioxidant, anti-inflammatory, and hepatoprotective properties. In this study, indigenous microalgal strains from fresh, brackish, and marine waters of Peninsular Malaysia were isolated, purified, and cultured. The potential of microalgae as a natural source of lipids and carotenoids was studied using a screening test with Nile red fluorescence dye to examine the lipid and carotenoid contents. Of 125 microalgae strains, nine strains isolated from marine and brackish water samples (Chaetoceros gracilis, Chlorella sp., C. sorokiniana, C. vulgaris, Tisochrysis lutea, Nitzschia capitellata, Oocystella heteromucosa, Oocystis marina, and Thalassiosira weissflogii) showed high fluorescence intensities. Next, the biochemical composition of these nine strains was examined. Thalassiosira weissflogii (strain TRG10-p105) showed the highest production of n-3 PUFAs and carotenoids among the nine strains. This strain produced high levels of n-3 PUFAs, particularly eicosapentaenoic acid (EPA). In this strain, the EPA contents relative to the dry weight (DW) and total fatty acid content (10.8% and 21.4%, respectively) were considerably higher than those reported in species currently used in industrial applications, such as aquaculture. Thalassiosira weissflogii TRG10-p105 had the highest total carotenoid content (20.2 mg g−1 DW), primarily because of its high fucoxanthin content (11.5 mg g−1 DW). The findings of this study indicate that T. weissflogii TRG10-p105 can serve as a high-value microalgal strain from tropical regions that produces n-3 PUFAs and carotenoids in abundance. Because a high ammonium tolerance was observed in this strain, its large-scale production can be implemented in ammonium-rich water produced from waste products to reduce the cost of algae production.

Extraction of Total DNA and RNA from Marine Filter Samples and Generation of a Universal cDNA as Universal Template for Marker Gene Studies.

Microbial communities play an important role in marine ecosystem processes. Although the number of studies targeting marker genes such as the 16S rRNA gene has increased during the last years, the vast majority of marine diversity are rather unexplored. Moreover, most studies focused on the entire microbial community and thus do not assess the active fraction of the microbial community. Here, we describe a detailed protocol for the simultaneous extraction of DNA and RNA from marine water samples and the generation of cDNA from the isolated RNA that can be used as a universal template in various marker gene studies.

Simultaneous quantification of all B vitamins and selected biosynthetic precursors in seawater and bacteria by means of different mass spectrometric approaches

B vitamins have high microbiological relevance in the marine environment, but their very low concentrations and the chemical heterogeneity of the individual vitamins make their analysis challenging. Mass spectrometric analysis of B vitamins in environmental samples at trace levels has mainly been performed using triple quadrupole mass spectrometers operated in targeted analysis mode. The development of such a method can be laborious and error prone. Additionally, high-resolution mass spectrometers can be used to measure a sample in full scan mode and subsequently search the total ion current chromatogram for extracted ion chromatograms of targeted vitamins. Three different analytical approaches for trace analysis of all B vitamins and some of their biosynthetic precursors were optimized and compared on two different mass spectrometers. A triple quadrupole mass spectrometer in selected reaction monitoring mode, and a high-resolution orbitrap mass spectrometer in parallel reaction monitoring, as well as in full scan mode were employed. Detection limits down to 10 ng/L were achieved with all three techniques. The methods were applied to a marine water sample from the North Sea and to the cell extract of a bacterial culture of Phaeobacter inhibens. Most vitamins and precursors were found in the bacterial cell extract and the seawater sample with all three measuring methods. The results of this study emphasize that, in addition to tandem mass spectrometry, high-resolution full scan mass spectrometry is a promising technique for the simultaneous detection of structurally diverse B vitamins in complex natural samples. This enables highly sensitive measurements without loss of detailed mass spectrometric information, which is inevitable when using a triple quadrupole system in MS/MS mode.Graphical abstract

Occurrence of Vibrio Species in Marine Sources Surroundings Bonaire, Dutch Caribbean

There is a lack of information on the presence of vibrios in the marine environment in the Caribbean. The aim of this study was to determine the occurrence of Vibrios in the coastal waters of Bonaire. Fifty samples of marine water collected at different depths from various sources around Bonaire were examined for the presence of vibrios. Species identification was confirmed by KB007 HiVibrioTM, Identification Kit, and TOFEL-MALDI. Forty of the samples contained Vibrio alginolyticus, 33 yielded V. parahaemolyticus and 29 showed the presence of V. vulnificus / V. cholerae. Regarding total colony counts in the sample, 47.4% of the colonies were V. alginolyticus, 35.2% were V. parahaemolyticus, and 17.4% represented V. vulnificus / V. cholerae. Further, of the 25 surface samples from various sites, 14 had a colony count percentage of 50% or greater number of V. alginolyticus. Another 10 sites had a colony count percentage of 50% or greater for V. parahaemolyticus; three of them had a colony count percentage of 50% or greater for V. vulnificus / V. cholerae. The present study constitutes the first study of its kind providing evidence of the prevalence of pathogenic Vibrio species, viz. V. alginolyticus, V. parahaemolyticus, and V. vulnificus / V. cholerae in marine water from the Dutch Caribbean.

Pyridinic N anchored Ag and Au hybrids for detoxification of organic pollutants

The development of a highly reusable, non-toxic catalyst for the effective removal of 4-nitrophenol (4-NP) from marine water is a key challenge due to its diverse effects on living organisms. Herein, in situ green fabricated pyridinic N anchored Ag2O/Au decorated porous silica (CG-Ag2O/Au-SiO2) using spent coffee grounds (CG) powder is introduced as a reusable catalyst to mitigate 4-NP, Methylene blue (MB), Rhodamine 6G (R6G) and their mixture in the spiked deionized, river and marine water samples. Exceptionally high structural activity and excellent reusability of catalysts up to 15 cycles have been demonstrated due to the accessibility of a large number of active sites from pyridinic N-anchored Ag2O and Au particle surfaces. CG-Ag2O/Au-SiO2 with the lower Ag and Au contents of 0.59 and 0.11 wt% (ICP-MS) of active catalytic sites exhibit a superior activity parameter of 6000 s−1 g−1 (4-NP), 6357 s−1 g−1 (MB), and 2892 s−1 g−1 (R6G) than chemically synthesized and reported, bare and hybrid structures. Furthermore, the CG-Ag2O/Au-SiO2 shows excellent stability in marine water with promising reusability performance (≈93% after 15 successive cycles). Density functional theory (DFT) studies reveal that the observed high catalytic efficiency originates from the pyridinic N presence on the Ag2O/Au structures.

Comparative Ichthyofaunal Observation of Freshwater Fishes of Shahabad Gulbarga District and Marine Water Fishes of Mangalore Districts of Karnataka

In this research project a comparison of ichthyofaunal diversity has been considered in the regions of Karnataka. Thus both freshwater and marine water samples have been taken for evaluation. For the freshwater sample collection the Shahabad region has been chosen and samples have been collected from Krishna and Bheema River as well as Bonal reservoir. For the marine sample collection coastal regions of Mangalore have been chosen. The samples have been further taxonomically identified to understand the order and family based distribution of the samples. As a obtained result and with the support of other scholarly articles, it has been identified that there is a greater marine diversity than freshwater diversity in the regions of Karnataka.

Toxicity of Herbicide, Paraquat Dichloride and Insecticide, Lambda-cyhalothrin on Phosphate Solubilizing Bacteria, Pantoa dispersa in Aquatic Ecosystems

Aim: The study was aimed to determine the toxicity of paraquat dichloride and lambda-cyhalothrin on phosphate solubilizing bacteria, Pantoa dispersa in aquatic ecosystems.
 Study Design: This study employs randomized block design, statistical analysis of the data and interpretation.
 Place and Duration of the Study: Soil sample was collected from the root nodules of leguminous plants in a sterile polythene bag from the Elele, in Etche L.G.A, Rivers State. The fresh water sample was collected from Bane town in Khana L.G.A, brackish water sample was collected from Choba river in Obio/Akpor L.G.A while the marine water was collected from Bonny River of Bonny L.G.A., all of Rivers State, Nigeria. The samples were collected aseptically and transported in an ice-pack immediately to the Rivers State University, Microbiology laboratory for analysis. The study lasted for three months.
 Methodology: The bacterium, Pantoa dispersa was isolated and identified based on conventional and molecular characterization from water and soil samples. Different concentrations (3.13%, 6.25, 12.50, 25.00%, 50.00% and 75.00%) and the control (0%) of the herbicide (paraquat dichloride) and insecticide, Lambda-cyhalothrin were prepared using fresh, brackish and marine water samples and 10ml of the test organism, Pantoa dispersa was introduced and the survival count was determined at 0, 4hr, 8hr, 12hr and 24hr. The Mean Lethal Concentration (LC50) of the insecticide and herbicide on Pantoa dispersa in the three aquatic ecosystem was determined.
 Results: The LC50 of the herbicide (Paraquat dichloride) was recorded as 15.8% in brackish water, 17.37% in fresh water and 27.44% in marine water. While the LC50 of the insecticide, Lambda-cyhalothrin to Pantoa dispersa was 26.84% in fresh water, 27.26% in brackish water and 32.33% in marine water.
 Conclusion: From the study, the herbicide, Paraquat dichloride was more toxic in the three aquatic ecosystems compared to the insecticide, Lambda-cyhalothrin. The use of these agrochemicals should be monitored as they result in the mortality of beneficial soil bacteria like Pantoa dispersa which is phosphate solubilizing bacteria in aquatic ecosystems.

Fast screening of enteropathogens in marine water samples.

This study aimed to fast screen the microbiological contamination of recreational waters using a TaqMan Array Card (TAC), a multiplexed platform designed for the simultaneous detection of 35 enteropathogens. Surface and deep marine water samples were concentrated by skimmed milk flocculation and processed for nucleic acid extraction protocol using QIAamp Fast DNA Stool Mini Kit. Twelve microorganisms and parasites, including bacteria (n = 6), protozoa (4), and viruses (2), were detected in 85.7% (24/28) of samples. Campylobacter (82.1%), Cryptosporidium (39.3%), and adenovirus (14.3%) were the most detected pathogens. Neither fungi nor helminths were detected. A spatial pollution profile of microbiological contamination was observed in the area. Methodologies for simultaneous detection of multiple pathogens, such as TAC, can assist decision-makers by providing a quick assessment of the microbiological water quality in areas used for recreational purposes, which in many cases are in accordance with the bacteriological indicators.

ISOLATION AND CHARACTERIZATION OF MARINE BACTERIA FOR CRUDE OIL DEGRADATION

Environmental spoilage of petroleum hydrocarbons handling is essential to safe our resources and health. The amount of natural crude oil seepage was estimated to be 600,000 metric tons per 2 year with a range of uncertainty of 200,000 metric tons per year. Oil spilled in water tends to spread and form a slick. From the findings wind and wave action, oil-in-water or water-in-oil emulsions may form. So the present study was carried out to isolate and characterize crude oil degrading microbes from crude oil contaminated marine water samples collected from Ennore, Tamil Nadu, India. The gravimetric analysis of degradation shows that two isolates, CDB1 and CDB2 among 5 isolates found to be potential for degradation of crude oil. The effective CDB1 and CDB2 isolates were further characterized morphological, physiological and Biochemical properties. The maximum crude oil degradation of 71.9% was achieved using CDB2 with 1% crude oil after 7 days of reaction. It is concluded that that the CDB2 isolate Such a bacterial species may be useful for preventing natural decontamination process.

Short‐term temporal variation of coastal marine eDNA

AbstractTemporal variation in eDNA signals is increasingly explored for understanding community ecology in aquatic habitats. Seasonal changes have been addressed using eDNA sampling, but very little is known regarding short‐term temporal variation that spans hours to days. To address this, we filtered marine water samples from a single coastal site in Denmark every hour for 32 h. We used metabarcoding to target both fish and broader eukaryote diversity and evaluated temporal changes in this marine community. Results revealed variation in fish species richness (15–27) and eukaryote class richness (35–64) across the 32 h of sampling, and we further evaluated sampling efforts needed to reach different levels of diversity saturation. Relative read frequency data for both fish and eukaryotes indicated a clear diel change in community composition, with different communities detected during daylight versus dark hours. The abundance signals in our data reflected biological variation rather than stochastic variation, since replicates taken at the same hour were more similar to each other than those taken at different hours. Our compositional results indicated a dynamic community, rather than a static pool of eDNA—even across a few hours. The fish data showed a daily pattern of relative species abundances, and the uncoupling of fish and broader eukaryote data suggest that variation in eDNA profiles across a single day can provide valuable information reflecting diel changes, at least for highly mobile organism groups. However, our results also point to several pitfalls in current eDNA experimental design, in which samples are taken over large areas without relative time‐consistency or short‐term replication. Our findings shed new light on short‐term variation in coastal eDNA and have wide implications for experimental study design and for incorporating temporality into project conceptualization for future aquatic biodiversity monitoring.

Definition of the Metagenomic Profile of Ocean Water Samples From the Gulf of Mexico Based on Comparison With Reference Samples From Sites Worldwide.

Computational and statistical analysis of shotgun metagenomes can predict gene abundance and is helpful for elucidating the functional and taxonomic compositions of environmental samples. Gene products are compared against physicochemical conditions or perturbations to shed light on the functions performed by the microbial community of an environmental sample; however, this information is not always available. The present study proposes a method for inferring the metabolic potential of metagenome samples by constructing a reference based on determining the probability distribution of the counts of each enzyme annotated. To test the methodology, we used marine water samples distributed worldwide as references. Then, the references were utilized to compare the annotated enzymes of two different water samples extracted from the Gulf of Mexico (GoM) to distinguish those enzymes with atypical behavior. The enzymes whose annotation counts presented frequencies significantly different from those of the reference were used to perform metabolic reconstruction, which naturally identified pathways. We found that several of the enzymes were involved in the biodegradation of petroleum, which is consistent with the impact of human hydrocarbon extraction activity and its ubiquitous presence in the GoM. The examination of other reconstructed pathways revealed significant enzymes indicating the presence of microbial communities characterizing each ocean depth and ocean cycle, providing a fingerprint of each sampled site.

Screening and optimization of candidate alkaline protease for dehairing potential from marine Bacillus paramycoides M2

Alkaline proteases are active from neutral to alkaline pH range and have extensive applications in detergent and leather industries. In the present research, bacteria isolated from marine water samples were screened for proteolytic activity. Among the isolates, M2 showed maximum proteolysis with a clear zone when cultured on skim milk agar plates at 37°C for 24 h. Molecular identification using 16S rRNA sequencing and phylogenetic analysis revealed that M2 has sequence identity (99.93%) to Bacillus paramycoides. SEM analysis was carried for determining the morphology of M2 and also for enzyme treated skin. FAME analysis using GCMS was performed for the determination of fatty acids in the strain. The selected isolate was inoculated into protease production medium under submerged fermentation conditions at 37ºC for 48 h with a constant agitation of 120 rpm. Protease activity was determined under varying conditions of pH, incubation temperature, carbon and nitrogen sources, metal ions and NaCl (1- 5%) using casein as substrate. The isolate M2 utilized molasses and peptone as carbon and nitrogen sources for better alkaline protease production at 40°C and pH 10 under optimal conditions. The dehairing experiments with M2 alkaline protease revealed dehairing efficacy of protease over chemical treatment. Hence, extracellular alkaline protease from M2 isolate could find potential application in leather processing industries and can be exploited commercially.

Study of L-Asparaginase from Marine Fungi and its Potential as an Anti-cancer Agent: A Preliminary Study using Chorioallantoic Membrane Assay

Introduction: L-asparaginase is a therapeutic enzyme that is used in combination therapy for mainly Acute Lymphocytic Leukemia (ALL) and other cancers. It hydrolyzes L-Asparagine required by neoplastic cells into L-aspartate and ammonia which leads to the death of tumor cells. But commercially available L-asparaginases show fatal side effects because of its prokaryotic source of origin, and associated glutaminase and urease co-activities. Aims: Screening of marine fungi for L- asparaginase activity and study of its potential as an anti – cancer agent. Methodology: This study was designed to isolate fungi from marine water and soil samples collected from regions of Maharashtra and Goa that are capable of producing L-asparaginase enzymes that are free of urease and glutaminase activity, and further study the potential of anticancer activity of these eucaryotic enzymes using Chorioallantoic membrane (CAM) assay. Result: Among all twelve marine fungi isolated, RF2 (identified as Aspergillusaculeatus (Genbank accession no.ON023823)) from Mandvi beach, Ratnagiri MH demonstrated high levels of L-asparaginase activity within 48-96 hrs, while lacking glutaminase and urease activity. Conclusion: The Chorioallantoic membrane (CAM) assay revealed that this fungal isolate could be a promising source of eucaryotic L-asparaginase to treat cancer with lower side effects.

Surveillance for Antibiotic-Resistant E. coli in the Salish Sea Ecosystem.

E. coli was isolated from the Salish Sea (Puget Sound) ecosystem, including samples of marine and fresh water, and wildlife dependent on this environment. E. coli isolates were assessed for phenotypic and genotypic resistance to antibiotics. A total of 305 E. coli isolates was characterized from samples collected from: marine water obtained in four quadrants of the Salish Sea; select locations near beaches; fresh water from streams near marine beaches; and fecal samples from harbor porpoises (Phocoena phocoena), harbor seals (Phoca vitulina), river otters (Lontra canadensis), and English sole (Parophrys vetulus). Isolates were evaluated using antimicrobial susceptibility typing, whole-genome sequencing, fumC, and multilocus sequence typing. Resistance and virulence genes were identified from sequence data. Of the 305 isolates from Salish Sea samples, 20 (6.6%) of the E. coli were intermediate, and 31 (10.2%) were resistant to ≥1 class of antibiotics, with 26.9% of nonsusceptible (resistant and intermediate resistant) E. coli isolates from marine mammals and 70% from river otters. The proportion of nonsusceptible isolates from animals was significantly higher than samples taken from marine water (p < 0.0001). A total of 196 unique STs was identified including 37 extraintestinal pathogenic E. coli (ExPEC)-associated STs [ST10, ST38, ST58, ST69, ST73, ST117, ST131, and ST405]. The study suggests that animals may be potential sentinels for antibiotic-resistant and ExPEC E. coli in the Salish Sea ecosystem.