Structural characterization of lipid A component of Erwinia carotovora lipopolysaccharide

The chemical structure of the lipid A component of lipopolysaccharide excreted into the liquid medium by the plant pathogenic enterobacterium Erwinia carotovora FERM P-7576 was characterized. It consists of a -1, 6-linked glucosamine disaccharide which carries ester-and amide-bound fatty acids and phosphate similar to the lipid A from other gram-negative bacteria. The lipid A preparation was not uniform in the number and composition of the fatty acids linked to the disaccharide. Four prominent lipids A were involved, they were composed of five to seven residues of fatty acid. Among them the major component was hexa-acyl lipid A, in which the hydroxyl group at position 3 and the amino group of the non-reducing glucosamine unit carry 3-dodecanoyl-oxytetradecanoyl residues. Positions 2 and 3 of the reducing glucosamine unit were substituted by 3-hydroxytetradecanoic acid. In the hepta-acyl lipid A, an additional hexadecanoic acid was linked to the hydroxyl group of the 3-hydroxytetradecanoyl residue at position 2 of the hexa-acyl lipid A. Two penta-acyl lipids A were the homologs of the hexa-acyl lipid A with decreasing acylation. Dodecanoic acid was missing from one, and 3-hydroxytetradecanoic acid from another. 3-Dodecanoyloxytetradecanoyl residue at position 3 differentiates E. carotovora lipid A from that of other gram-negative bacteria.Abbreviations LPS lipopolysaccharide - GlcN glucosamine - KDO 3-deoxy-d-manno-octulosonic acid - FAB-MS fast atom bombardment mass spectrometry - u atomic mass unit     

scRNA-seq Analysis of Hemocytes of Penaeid Shrimp Under Virus Infection

Marine Biotechnology - The classification of cells in non-model organisms has lagged behind the classification of cells in model organisms that have established cluster of differentiation marker...     

Kinetics of growth and lactic acid production in continuous and batch culture

Summary In a lactic acid fermentation by Streptococcus faecalis, the specific consumption rate of glucose (v) and the specific production rate of lactic acid () were represented by the following simple equations as functions of the specific growth rate (): 1/=(1/) + 1/ = (1/) + By use of data from a batch culture, these two equations were derived from enzyme kinetics of the product inhibition. These equations were successfully applied to the results of batch culture and chemostat culture. In addition, calculation of ATP yield by these equations agreed with the experimental results better than the conventional Leudeking-Piret type equation, which includes two terms associated with growth and not with growth. Correspondence to: H. Ohara     

Aldehyde reductase gene expression by lipid peroxidation end products,MDA and HNE

Membrane lipid peroxidation results in the production of a variety of aldehydic compounds that play a significant role in aging, drug toxicity and the pathogenesis of a number of human diseases, such as atherosclerosis and cancer. Increased lipid peroxidation and reduced antioxidant status may also contribute to the development of diabetic complications. This study reports that lipid peroxidation end products such as malondialdehyde (MDA) and 4-hydroxynonenal (HNE) induce aldehyde reductase (ALR) gene expression. MDA and HNE induce an increase in intracellular peroxide levels; N-Acetyl-L-cysteine (NAC) suppressed MDA- and HNE-induced ALR gene expression. These results indicate that increased levels of intracellular peroxides by MDA and HNE might be involved in the upregulation of ALR.     

Genetic exchange between two freshwater apple snails, Pomacea canaliculata and Pomacea maculata invading East and Southeast Asia

Two species of apple snails, Pomacea canaliculata and Pomacea maculata (formerly Pomacea insularum), have invaded many countries of East and Southeast Asia from their native range in South America. This study investigated the genetic structure of the two species invading these areas. Phylogenetic analysis based on sequences of the nuclear gene elongation factor 1-alpha (EF1α) detected two well-supported clades (Clade C and Clade M). Both P. canaliculata and P. maculata were represented in each clade. Some snails had both Clade C and Clade M EF1α sequences. These results suggest genetic exchange between snails of the two clades. A mating experiment between P. canaliculata with Clade C EF1α sequences and P. maculata with Clade M EF1α sequences resulted in viable F1 progeny under laboratory conditions. The genetic exchange was also inferred in some populations collected from Argentina, suggesting an existence of hybrid in the native range. Simple identification of EF1α types using a restriction enzyme, ApaLI, detected significant geographical structure of the EF1α variants in the invaded area. The divergent geographical structure could have resulted from either the founder effect or the bridgehead effect, although further genetic analysis is needed to clarify this. Average individual egg weight, which is an indicator of egg size, was higher in P. canaliculata than P. maculata in both field and laboratory reared samples, suggesting that some (probably most) P. canaliculata and P. maculata invading East and Southeast Asia still maintain species-specific populations.     

Effect of Additional Protein or Methionine and Threonine on Tyrosine Catabolism in Rats Fed Diets High in Tyrosine

The supplementation of additional protein or methionine and threonine to a high tyrosinc-low protein diet has previously been shown to prevent the tyrosine toxicity. To elucidate the mechanism, studies were performed on the effect of these supplements on the capacity to oxidize excessive tyrosine. Male weanling rats were ad libitum fed a 10% casein diet containing 5% tyrosine with and without extra casein or methionine plus threonine for 7 days, then animals were injected intraperitoneally with l-tyrosine-U-¹⁴C and the oxidation rate to ¹⁴CO₂ determined in vivo at an interval of several hours throughout a 24-hour period. The addition of extra casein or methionine and threonine to the high tyrosine diet enhanced the ability of tyrosine oxidation, and decreased the radioactivities of the TCA-soluble fractions in plasma, liver and muscle. A high level of free tyrosine in blood and tissues was also lowered by the addition of these supplements. The diurnal chenges in free tyrosine concentration of various tissues were observed. The data suggest that the beneficial effect of extra casein or methionine and threonine supplementation on tyrosine toxicity is due to an increased rate of tyrosine catabolism which results in lower tyrosine concentrations in body fluids which overcomes tyrosine toxicity.     

α-Aminoisobutyric Acid as the Constituent Amino Acid of Protein

α-Aminoisobutyric acid is the only tertiary amino acid which is reported to occur in the proteins. Nevertheless, this amino acid has not been yet isolated from the proteins. Recently we succeeded in isolating this amino acid as white prismy crystalline substance from both acid and pepsin hydrolysate of horse hind leg muscle proteins, and this crystal was identified to be α-amino-isobutyric acid by elementary analysis, properties of this derivates, etc.     

Effects of Alloxan Diabetes and Hypophysectomy on Growth,and Plasma and Liver Free Amino Acids of Rats Fed Excess Glycine Diets

Three chitinases (EC 3.2.1.14) were purified from yam, Dioscorea opposita THUMB, by fractionation with ammonium sulfate, chromatographies on DEAE-Cellulose and DEAE-Sephadex A-50, chromatofocusing and gel filtration on Bio-Gel P-60. The purified enzymes (E-l, E-2 and E-3) showed single bands on sodium dodecylsulfate polyacrylamide gel electrophoresis, and the molecular weights were estimated to be 33,500. The pIs were 4.05 (E-l), 4.0 (E-2) and 3.8 (E-3). All enzymes were glycoproteins and the neutral sugar contents were 3.6% (E-l), 3.6 (E-2) and 0.9% (E-3). The N-terminal amino acids of E-l and E-3 were the same and determined to be histidine. All enzymes hydrolyzed glycolchitin, but not p-nitrophenyl-2-acetamido-2-deoxy-β-d-glucopyranoside or Micrococcus lysodeikticus cell walls. E-l and E-3 were stable in the pH range of 5 ~ 11, and below 60°C. These enzymes showed two optimum pHs around 3.5 and 8.0 or 8.5 with glycolchitin as substrate.