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International Journal of Environmental... Mar 2019The single toxicity (IC) of zinc (Zn) and 11 nitro-substituted benzenes to were determined, respectively. On basis of single toxicity, the joint toxicity of binary...
The single toxicity (IC) of zinc (Zn) and 11 nitro-substituted benzenes to were determined, respectively. On basis of single toxicity, the joint toxicity of binary mixtures of Zn and 11 nitro-substituted benzenes at different Zn concentrations of 0.2 IC, 0.5 IC, and 0.8 IC were measured. The joint toxicity was evaluated by toxic unit (TU) and additive index (AI) methods. The results indicated that the joint toxicity was not only depending on the Zn concentrations but also on the substituted groups of nitro-substituted benzenes. The quantitative structure-activity relation (QSAR) equations were developed and the results showed that the toxicity of nitro-substituted benzenes has different joint effect at the different Zn concentrations. At the Zn concentration of 0.2 IC, the binary joint effects were mainly antagonism and the joint toxicity was negatively related to descriptors called VE2_B(p) and TIC3. At the Zn concentration of 0.5 IC and 0.8 IC, the binary joint effects were mainly antagonism and simple addition, and the joint toxicity was related to the same descriptor Eig06_ AEA(dm). It indicated that the joint toxic actions were similar when combined at the medium and high concentrations of Zn.
Topics: Benzene; Photobacterium; Quantitative Structure-Activity Relationship; Zinc
PubMed: 30909451
DOI: 10.3390/ijerph16061041 -
Frontiers in Microbiology 2022Modified atmosphere packaging (MAP) is a common strategy to selectively prevent the growth of certain species of meat spoiling bacteria. This study aimed to determine...
Modified atmosphere packaging (MAP) is a common strategy to selectively prevent the growth of certain species of meat spoiling bacteria. This study aimed to determine the impact of high oxygen MAP (70% O, 30% CO, red and white meats) and oxygen-free MAP (70% N, 30% CO, also white meat and seafood) on preventing the growth of spoiling photobacteria on meat. Growth of and was monitored in a meat simulation media under different gas mixtures of nitrogen, oxygen, and carbon dioxide, and samples were taken during exponential growth for a comparative proteomic analysis. Growth under air atmosphere appears optimal, particularly for . Enhanced protein accumulation affected energy metabolism, respiration, oxygen consuming reactions, and lipid usage. However, all the other atmospheres show some degree of growth reduction. An increase in oxygen concentration leads to an increase in enzymes counteracting oxidative stress for both species and enhancement of heme utilization and iron-sulfur cluster assembly proteins for . Absence of oxygen appears to switch the metabolism toward fermentative pathways where either ribose ( or glycogen ( appear to be the preferred substrates. Additionally, it promotes the use of alternative electron donors/acceptors, mainly formate and nitrate/nitrite. Stress response is manifested as an enhanced accumulation of enzymes that is able to produce ammonia (e.g., carbonic anhydrase, hydroxylamine reductase) and regulate osmotic stress. Our results suggest that photobacteria do not sense the environmental levels of carbon dioxide, but rather adapt to their own anaerobic metabolism. The regulation in presence of carbon dioxide is limited and strain-specific under anaerobic conditions. However, when oxygen at air-like concentration (21%) is present together with carbon dioxide (30%), the oxidative stress appears enhanced compared to air conditions (very low carbon dioxide), as explained if both gases have a synergistic effect. This is further supported by the increase in oxygen concentration in the presence of carbon dioxide. The atmosphere is able to fully inhibit , heavily reduce growth , and trigger diversification of energy production with higher energetic cost, highlighting the importance of concomitant bacteria for their growth on raw meat under said atmosphere.
PubMed: 35722325
DOI: 10.3389/fmicb.2022.866629 -
Frontiers in Microbiology 2022Decapod iridescent virus 1 (DIV1) has caused severe economic losses in shrimp aquaculture. So far, Researchs on DIV1-infected shrimp have mainly focused on the hemocytes...
INTRODUCTION
Decapod iridescent virus 1 (DIV1) has caused severe economic losses in shrimp aquaculture. So far, Researchs on DIV1-infected shrimp have mainly focused on the hemocytes immune response, while studies on the host-intestine microbiota interactions during DIV1 infection have been scarce.
METHODS
This study determined the lethal concentration 50 (LC) of DIV1 to , preliminarily determining that could serve as a susceptible object for DIV1. The interactions and responses between the immune and intestine microbiota of shrimp under DIV1 infection were also investigated.
RESULTS AND DISCUSSION
DIV1 infection decreases intestine bacterial diversity and alters the composition of intestine microbiota. Specifically, DIV1 infection decreases the abundance of potentially beneficial bacteria (Bacteroidetes, Firmicutes, and Actinobacteria), and significantly increases the abundance of pathogenic bacteria such as and , thereby increasing the risk of secondary bacterial infections. The results of PICRUSt functional prediction showed that altered intestine microbiota induces host metabolism disorders, which could be attributed to the bioenergetic and biosynthetic requirements for DIV1 replication in shrimp. The comparative transcriptomic analysis showed that some metabolic pathways related to host immunity were significantly activated following DIV1 infection, including ncRNA processing and metabolic process, Ascorbate and aldarate metabolism, and Arachidonic acid metabolism. may against DIV1 infection by enhancing the expression of some immune-related genes, such as Wnt16, heat shock protein 90 (Hsp90) and C-type lectin 3 (Ctl3). Notably, correlation analysis of intestinal microbial variation with host immunity showed that expansion of pathogenic bacteria ( and ) in DIV1 infection could increased the expression of NF-κB inhibitors cactus-like and Toll interacting protein (Tollip), which may limit the TLR-mediated immune response and ultimately lead to further DIV1 infection.
SIGNIFICANCE AND IMPACT OF THE STUDY
This study enhances our understanding of the interactions between shrimp immunity and intestinal microbiota. The ultimate goal is to develop novel immune enhancers for shrimp and formulate a safe and effective DIV1 defense strategy.
PubMed: 36713173
DOI: 10.3389/fmicb.2022.1097931 -
Marine Environmental Research Apr 2024The New Zealand Greenshell™ mussel (Perna canaliculus) is an economically important aquaculture species. Prolonged increases in seawater temperature above mussel...
Interactive effects of elevated temperature and Photobacterium swingsii infection on the survival and immune response of marine mussels (Perna canaliculus): A summer mortality scenario.
The New Zealand Greenshell™ mussel (Perna canaliculus) is an economically important aquaculture species. Prolonged increases in seawater temperature above mussel thermotolerance ranges pose a significant threat to mussel survival and health, potentially increasing susceptibility to bacterial infections. Using challenge experiments, this study examined the combined effects of increased seawater temperature and bacterial (Photobacterium swingsii) infection on animal survival, haemocyte and biochemical responses of adult mussels. Mussels maintained at three temperatures (16, 20 and 24 °C) for seven days were either not injected (control), injected with sterile marine broth (injection control) or P. swingsii (challenged with medium and high doses) and monitored daily for five days. Haemolymph and tissue samples were collected at 24, 48, 72, 96, 120 h post-challenge and analysed to quantify bacterial colonies, haemocyte responses and biochemical responses. Mussels infected with P. swingsii exhibited mortalities at 20 and 24 °C, likely due to a compromised immune system, but no mortalities were observed when temperature was the only stressor. Bacterial colony counts in haemolymph decreased over time, suggesting bacterial clearance followed by the activation of immune signalling pathways. Total haemocyte counts and viability data supports haemocyte defence functions being stimulated in the presence of high pathogen loads at 24 °C. In the gill tissue, oxidative stress responses, measured as total antioxidant capacity and malondialdehyde (MDA) levels, were higher in infected mussels (compared to the controls) after 24h and 120h post-challenge at the lowest (16 °C) and highest temperatures (24 °C), indicating the presence of oxidative stress due to temperature and pathogen stressors. Overall, this work confirms that Photobacterium swingsii is pathogenic to P. canaliculus and indicates that mussels may be more vulnerable to bacterial pathogens under conditions of elevated temperature, such as those predicted under future climate change scenarios.
Topics: Animals; Temperature; Perna; Photobacterium; Immunity
PubMed: 38364448
DOI: 10.1016/j.marenvres.2024.106392 -
Toxins Jul 2019Phobalysin P (PhlyP, for photobacterial lysin encoded on a plasmid) is a recently described small β-pore forming toxin of subsp. This organism, belonging to the... (Review)
Review
Phobalysin P (PhlyP, for photobacterial lysin encoded on a plasmid) is a recently described small β-pore forming toxin of subsp. This organism, belonging to the family of is an emerging pathogen of fish and various marine animals, which occasionally causes life-threatening soft tissue infections and septicemia in humans. By using genetically modified strains, PhlyP was found to be an important virulence factor. More recently, in vitro studies with purified PhlyP elucidated some basic consequences of pore formation. Being the first bacterial small β-pore forming toxin shown to trigger calcium-influx dependent membrane repair, PhlyP has advanced to a revealing model toxin to study this important cellular function. Further, results from co-culture experiments employing various strains and epithelial cells together with data on other bacterial toxins indicate that limited membrane damage may generally enhance the association of bacteria with target cells. Thereby, remodeling of plasma membrane and cytoskeleton during membrane repair could be involved. In addition, a chemotaxis-dependent mechanism influenced by environmental factors like salinity may contribute to PhlyP-dependent association of with cells. Obviously, a synoptic approach is required to capture the regulatory links governing the interaction of with target cells. The characterization of secretome may hold additional clues because it may lead to the identification of proteases activating PhlyP's pro-form. Current findings on PhlyP support the notion that pore forming toxins are not just killer proteins but serve bacteria to fulfill more subtle functions, like accessing their host.
Topics: Animals; Bacterial Proteins; Cell Adhesion; Cell Membrane; Chemotaxis; Epithelial Cells; Hemolysin Proteins; Humans; Phenotype; Photobacterium
PubMed: 31315179
DOI: 10.3390/toxins11070412 -
Frontiers in Nutrition 2022Herein, we present a method for producing water-soluble polysaccharides (WSPs) by co-culture fermentation of straw and shrimp shells. The chitin-degrading strain was...
Herein, we present a method for producing water-soluble polysaccharides (WSPs) by co-culture fermentation of straw and shrimp shells. The chitin-degrading strain was isolated and genotypically identified as the non-pathogen sp. LYM-1 in this study. sp. LYM-1 and 2012 could coexist without antagonism. WSPs concentrations were higher in co-culture fermentations of sp. LYM-1 and 2012 (PsL/AP-WSPs) compared to monocultures (PsL-WSPs and AP-WSPs). FTIR was used to examine the polysaccharide properties of three WSP fractions. The monosaccharide compositions of three WSPs fractions were primarily composed of mannose, ribose, glucosamine, glucose, galactose, and arabinose with varying molecular weights and molar ratios according to HPLC analysis. PsL/AP-WSPs showed better scavenging effects on DPPH, ABTS, and OH free radicals, demonstrating the application potential of PsL/AP-WSPs from straw and shrimp shells. The maximum yield obtained under optimum conditions (fermentation time of 6 days, temperature of 31°C, inoculum concentration of 10% (w/v), and inoculum composition of 2:1) was 5.88 ± 0.40 mg/mL, based on the PsL/AP-WSPs production optimization by orthogonal design. The results suggest that an environmentally friendly approach for WSPs production from agro-food wastes straw and shrimp shells was developed.
PubMed: 36479299
DOI: 10.3389/fnut.2022.1047932 -
Molecules (Basel, Switzerland) Jul 2022This study aimed to evaluate the antibacterial activity in vitro of and extracts against potentially pathogenic bacteria for Pacific white shrimp. Furthermore, the...
This study aimed to evaluate the antibacterial activity in vitro of and extracts against potentially pathogenic bacteria for Pacific white shrimp. Furthermore, the extracts with higher inhibitory activity were analyzed to identify compounds responsible for bacterial inhibition and evaluate their effect on motility and biofilm formation. and extracts were prepared using methanol, acetone, and hexane by ultrasound. The minimum inhibitory concentration (MIC) of the extracts was determined against and . The polyphenol profile of those extracts showing the highest bacterial inhibition were determined. Besides, the bacterial swimming and swarming motility and biofilm formation were determined. The highest inhibitory activity against the four pathogens was found with the acetonic extract of leaf (MIC of 50 mg/mL for spp. and 25 mg/mL for spp.) and the methanol extract of flower (MIC of 50 mg/mL for all pathogens tested). Both extracts affected the swarming and swimming motility and the biofilm formation of the tested bacteria. The main phenolic compounds related to bacteria inhibition were naringin, vanillic acid, and rosmarinic acid, whilst hesperidin, kaempferol pentosyl-rutinoside, and rhamnetin were related to bacteria inhibition.
Topics: Animals; Anti-Bacterial Agents; Methanol; Microbial Sensitivity Tests; Penaeidae; Plant Extracts; Vibrio parahaemolyticus
PubMed: 35889267
DOI: 10.3390/molecules27144397 -
Animals : An Open Access Journal From... Nov 2022Bacteria belonging to the species are pathogens of cultured marine fish, causing diseases of high importance, such as Pasteurellosis. Thus, they are considered a major...
Bacteria belonging to the species are pathogens of cultured marine fish, causing diseases of high importance, such as Pasteurellosis. Thus, they are considered a major threat to the aquaculture sector. Despite the great importance of fish mariculture for the Greek economy, the distribution and abundance of these bacteria are not well documented in aquaculture units in Greece. Keeping this in mind, the scope of the present study was to investigate the presence, antibiotic profile, and virulence of bacteria originating from a representative sample of mariculture units throughout Greece. Samples were collected from diseased fish belonging to three different cultured fish species, namely , and from both the Aegean and the Ionian Sea. Tissue samples were cultured in agar media, and bacteria were molecularly identified using both bacterial universal and species-specific primer pairs for spp. Additionally, the identified strains were characterized for the presence of virulence genes as well as antibiotic profiles. According to the results, the aforementioned bacteria are distributed in the Greek aquaculture units and are characterized by high pathogenicity based on the abundance of virulence genes. Furthermore, the majority of the detected strains exhibit some level of antibiotic resistance. In summary, our results indicate the need for systematic surveillance and study of their antibiotic profiles in Greek aquaculture since these bacteria constitute a major threat to the sector.
PubMed: 36428362
DOI: 10.3390/ani12223133 -
International Journal of Food... Feb 2016Accumulation of volatile organic compounds was monitored in association with sensory quality, bacterial concentrations and culture-independent microbial community...
Accumulation of volatile organic compounds was monitored in association with sensory quality, bacterial concentrations and culture-independent microbial community analyses in raw pork loin and pork collar during storage under high-oxygen modified atmosphere at +4 °C. Of the 48 volatile compounds detected in the pork samples, the levels of acetoin, diacetyl and 3-methyl-1-butanol had the highest correlations with the sensory scores and bacterial concentrations. These compounds accumulated in all of the four monitored lots of non-sterile pork but not in the sterilized pork during chilled storage. According to the culture-dependent and culture-independent characterization of bacterial communities, Brochothrix thermosphacta, lactic acid bacteria (Carnobacterium, Lactobacillus, Lactococcus, Leuconostoc, Weissella) and Photobacterium spp. predominated in pork samples. Photobacterium spp., typically not associated with spoilage of meat, were detected also in 8 of the 11 retail packages of pork investigated subsequently. Eleven isolates from the pork samples were shown to belong to Photobacterium phosphoreum by phenotypic tests and sequencing of the 16S rRNA and gyrB gene fragments. Off-odors in pork samples with high proportion of Photobacterium spp. were associated with accumulation of acetoin, diacetyl and 3-methyl-1-butanol in meat, but these compounds did not explain all the off-odors reported in sensory analyses.
Topics: Acetoin; Animals; Carnobacterium; DNA Gyrase; Diacetyl; Food Microbiology; Food Packaging; Gas Chromatography-Mass Spectrometry; Lactococcus; Leuconostoc; Odorants; Pentanols; Photobacterium; RNA, Ribosomal, 16S; Red Meat; Swine; Volatile Organic Compounds
PubMed: 26623935
DOI: 10.1016/j.ijfoodmicro.2015.11.003 -
International Journal of Molecular... Aug 2022The genus is known for its ecophysiological versatility encompassing free-living, symbiotic, and pathogenic lifestyles. sp. CCB-ST2H9 was isolated from estuarine...
The genus is known for its ecophysiological versatility encompassing free-living, symbiotic, and pathogenic lifestyles. sp. CCB-ST2H9 was isolated from estuarine sediment collected at Matang Mangrove, Malaysia. In this study, the genome of CCB-ST2H9 was sequenced, and the pan-genome of 37 strains was analysed. Phylogeny based on core genes showed that CCB-ST2H9 clustered with , forming a distinct clade with , , and . The core genome of was conserved in housekeeping functions, while the flexible genome was well represented by environmental genes related to energy production and carbohydrate metabolism. Genomic metrics including 16S rRNA sequence similarity, average nucleotide identity, and digital DNA-DNA hybridization values were below the cut-off for species delineation, implying that CCB-ST2H9 potentially represents a new species. Genome mining revealed that biosynthetic gene clusters (BGCs) involved in producing antimicrobial compounds such as holomycin in CCB-ST2H9 could contribute to the antagonistic potential. Furthermore, the EtOAc extract from the culture broth of CCB-ST2H9 exhibited antagonistic activity against spp. Intriguingly, clustering based on BGCs profiles grouped , , , , and CCB-ST2H9 together in the heatmap by the presence of a large number of BGCs. These BGCs-rich strains represent great potential for bioactive secondary metabolites production and sources for novel compounds.
Topics: Bacterial Typing Techniques; Base Composition; DNA, Bacterial; Fatty Acids; Genomics; Multigene Family; Photobacterium; Phylogeny; RNA, Ribosomal, 16S; Sequence Analysis, DNA
PubMed: 36077108
DOI: 10.3390/ijms23179712