Significance of Na+in the fish pathogen,Vibrio anguillarum, under energy depleted condition

The elements of life: A biocentric tour of the periodic table

Living systems are built from a small subset of the atomic elements, including the bulk macronutrients (C,H,N,O,P,S) and ions (Mg,K,Na,Ca) together with a small but variable set of trace elements (micronutrients). Here, we provide a global survey of how chemical elements contribute to life. We define five classes of elements: those that are (i) essential for all life, (ii) essential for many organisms in all three domains of life, (iii) essential or beneficial for many organisms in at least one domain, (iv) beneficial to at least some species, and (v) of no known beneficial use. The ability of cells to sustain life when individual elements are absent or limiting relies on complex physiological and evolutionary mechanisms (elemental economy). This survey of elemental use across the tree of life is encapsulated in a web-based, interactive periodic table that summarizes the roles chemical elements in biology and highlights corresponding mechanisms of elemental economy.

Prevalence, Antibiotic-Resistance, and Growth Profile of Vibrio spp. Isolated From Fish and Shellfish in Subtropical-Arid Area

The study aimed to determine the prevalence of different species of Vibrio spp. in fish and shellfish sold in subtropical-arid countries (United Arab Emirates). It also examined the antimicrobial resistance of the isolated species and their growth behavior upon in vitro environmental changes concerning temperature, pH, and salinity. The prevalence of Vibrio spp. in fish and shellfish samples, was 64.5 and 92%, respectively. However, Vibrio parahemolyticus were detected in a mere 7.5 and 13.0% of the samples, respectively. On the other hand, Vibrio mimicus was detected in 1.5 and 8.5% of the samples, respectively. None of the six antibiotics studied except for Sulfamethoxazole-trimethoprim were effective against fish Vibrio spp. isolates. On a similar note, three antibiotics, namely Penicillin, Daptomycin, and Vancomycin, were ineffective against the shellfish isolates. The growth of the microorganisms did not show any significant trend with changes in pH and salinity. The optimum temperature for Vibrio spp. growth was observed to be 37°C.

Effect on amino acid and mineral content of the loach (Misgurnus anguillicaudatus) by adding Fe (II) chelating hairtail protein hydrolysates (Fe (II)-HPH) to the feed

To study the effect on amino acid and mineral content of the loach meat by adding Fe (II) chelating hairtail protein hydrolysates (Fe (II)-HPH) to the feed. A total of 100 healthy loaches were selected. After 1 week's adaptive feeding, they were randomly divided into five groups and fed with feeds containing of Fe (II)-HPH (0, 0.5, 1, 2, and 4 g/kg). On the 40th day, detection work of general nutrients (moisture, ash, crude protein, and crude fat), mineral elements (Fe, Mn, Cu, Zn, Na, K, and Ca), amino acid and amino acid score (AAS), Chemical Score (CS) and essential amino acid index (EAAI) indexes were done. The results show that crude protein has the highest content while crude fat has the lowest when amount of added Fe (II)-HPH in feed is 2 g/kg. The Fe content is significantly improved while amount of added is 1, 2, 4 g/kg. The Ca content is significantly improved and the Zn content is significantly improved while amount of added was 2 g/kg. Mn contents are significantly lower than control while amount of added is 4 g/kg. Based on analysis of amino acids in each group, the nutritional value of loach meat with 2 g/kg Fe (II)-HPH addition amount is relatively high, total amount of essential amino acids increases significantly, and EAA/TAA and EAA/NEAA improve significantly. In conclusion, adding 2 g/kg Fe (II)-HPH to feed could improve the nutritional values of loach meat.

Survival, Virulent Characteristics, and Transcriptomic Analyses of the Pathogenic Vibrio anguillarum Under Starvation Stress

Many bacteria have developed strategies for metamorphosis into sophisticated survival forms to survive extended periods of environmental stress. As a global causative agent of vibriosis in marine fish farming, Vibrio anguillarum (V. anguillarum) can efficiently grow and proliferate under environmental stress, but the specific mechanism is not clear. In the present study, survival, virulent characteristics, and transcriptomic analysis of the V. anguillarum BH1 were performed under starvation stress. The results demonstrated that V. anguillarum was still culturable and showed rippled surface after 6 months of starvation. Starved cells maintained their infectivity in half-smooth tongue sole (Cynoglossus semilaevi). Detection of virulence factors and virulence-associated genes in starved cells showed that the starved strain still produced β-hemolysis on rabbit blood agar, caseinase, dnase, and gelatinase, and possessed empA, vah1, vah2, vah3, vah4, vah5, rtxA, flaA, flaD, flaE, virC, tonB, mreB, toxR, rpoS, and ftsZ virulence-related genes. In addition, we first reported the RNA-seq study for V. anguillarum with and without starvation treatment for a period of 6 months and emphasized the regulation of gene expression at the whole transcriptional level. It indicated that V. anguillarum expressed 3,089 and 3,072 genes in the control group and starvation stress group, respectively. The differently expressed genes (DEGs) of the starved strain were thereby identified, including 251 up-regulated genes and 272 down-regulated genes in comparison with the non-starved strain. Gene Ontology (GO) analysis and Kyto Encyclopedia Genes and Genomes (KEGG) enrichment analysis of DEGs were also analyzed. GO functional classification revealed that among the significantly regulated genes with known function categories, more genes affiliated with signal transducer activity, molecular transducer activity, and cell communication were significantly up-regulated, and more genes affiliated with cellular macromolecule, cellular component, and structural molecule activity were significantly down-regulated. In addition, the DEGs involved in the pathway of two-component system was significantly up-regulated, and the pathways of ribosome and flagellar assembly were significantly down-regulated. This study provides valuable insight into the survival strategies of V. anguillarum and suggests that a portion of the bacterial populations may remain pathogenic while persisting under starvation stress by up-regulating or down-regulating a series of genes.

A preliminary investigation on the growth requirement for monovalent cations, divalent cations and medium ionic strength of marine actinomycete Salinispora

In this paper, we report that three species of Salinispora, S. arenicola, S. tropica, and S. pacifica, require magnesium and calcium, for growth, with S. pacifica having the most stringent growth requirement for these ions. Interaction between these ions in supporting the growth of Salinispora was observed. We also demonstrated that the absolute requirement of sodium to support the growth of Salinispora has not been established as all three species of Salinispora can use either potassium or lithium to replace sodium to support maximum growth. While lithium can replace sodium to support maximum growth of Salinispora, it is more toxic to S. arenicola than S. tropica and S. pacifica, inhibiting the growth of S. arenicola at 189 mM but without effect on the growth of S. tropica and S. pacifica. Using both sodium chloride-based and lithium chloride-based media, we showed that Salinispora has a growth requirement for divalent ions, magnesium and calcium as well as growth requirement for ionic strength (8.29 to 15.2 mS/cm). S. arenicola has a lower growth requirement for ionic strength than S. tropica and S. pacifica.

The effect of oral immuno-stimulation in juvenile carp (Cyprinus carpio L.)

The effect of a 2-week period of oral immuno-stimulation from the age of 2 or 6 weeks post-fertilisation (wpf; before and after reaching the ability to produce antibodies) onwards was investigated on various immune functions of the common carp, Cyprinus carpio. The immuno-stimulants Aeromonas salmonicida lipopolysaccharide, Yeast DNA (containing unmethylated CpG motifs) or high-M alginate (an extract of algae containing poly-mannuronic acid) were used. The effect of this treatment was studied on the kinetics of B cells in head kidney and peripheral blood leucocytes using flow cytometry, on the total plasma IgM level using ELISA, on cytokine and inducible nitric oxide synthase (iNOS) expression in the intestine, and acute phase protein expression in the liver, using real time quantitative PCR, and on exposure to Vibrio anguillarum. Oral administration of immuno-stimulants from 6 wpf resulted in decreased WCI12(+) (B) cell percentages in PBL (only after administration of LPS) and head kidney (all test groups), and a decreased total IgM level in plasma, suggesting that suppressive effects are strongly indicative of oral or juvenile tolerance. After administration from 2 wpf, the effects on WCI12(+) (B) cell percentages were less pronounced: the group fed with Yeast DNA showed higher percentages compared to the control group at 6 wpf, but lower percentages at 8 wpf. No changes were observed in the cytokine or iNOS expression levels in the intestine or acute phase protein expression in the liver. A challenge with V. anguillarum resulted in an initially higher cumulative mortality in the group fed with LPS, but lower mortality in the groups fed with Yeast DNA or high-M alginate compared to the control group, providing a provisional warning especially for the use of pathogen-derived immuno-stimulants, such as A. salmonicida LPS, in larval and juvenile fish.