cDNA cloning and expression of a novel group IB phospholipase A2 in the intestine of the red sea bream,Pagrus (Chrysophrys) major

A cDNA encoding a novel phospholipase A₂ (PLA₂), which was named IN PLA₂, was cloned from the intestine of the red sea bream. The amino acid sequence of IN PLA₂ showed 49–75% homology with those of red sea bream group IB sPLA₂, hepatopancreas DE-1 and DE-2 PLA₂, and gill G-3 PLA₂. IN PLA₂ consists of a prepropeptide of 24 amino acid residues, followed by a mature protein. IN PLA₂ contains 14 cysteines, and includes Cys11, the calcium binding loop and the pancreatic loop that are commonly conserved in group IB sPLA₂ enzymes. In addition, IN PLA₂ is a cationic protein with a pI of 8.52. Therefore, IN PLA₂ was identified as a novel group IB sPLA₂ isoform in red sea bream. IN PLA₂ mRNA was found by northern blot analysis to be expressed mainly in the pyloric caeca and the intestine, and was detected in the goblet cells of the intestine by in situ hybridization. The expression level of IN PLA₂ mRNA was elevated by intravenous injection of lipopolysaccharide—the outer-membrane component of Gram-negative bacteria. These results suggest that IN PLA₂ is secreted from the goblet cells of the intestine in response to stimulus such as bacterial infection, and that it contributes to antimicrobial defense in addition to the digestion of dietary phospholipids in the gastrointestinal tract.     

A PCR assay to specifically detect serovar 1a strains of Erysipelothrix rhusiopathiae and differentiate them from serovar 2 strains possessing an intact ERH_1440 gene

The Erysipelothrix rhusiopathiae ERH_1440 gene, which encodes CDP-glycerol:poly (glycerophosphate) glycerophosphotransferase, is conserved in serovar 1a strains. The gene is usually missing or truncated in other serovar strains and therefore has been used for PCR detection of serovar 1a strains. We have previously reported a rare case of an E. rhusiopathiae serovar 2 strain possessing an intact ERH_1440. In this study, we analyzed three additional serovar 2 strains with an intact ERH_1440 and developed a new PCR assay for the specific detection and differentiation of serovar 1a strains from these serovar 2 strains. PCR with primers designed based on serovar 1a-specific gene sequences upstream of ERH_1440 showed 100% specificity for four hundred thirty Erysipelothrix strains isolated from extensive origins.     

Cytological and microsatellite mapping of mutant genes for spherical grain and compact spikes in durum wheat

Two mutants for sphaerococcoid seed (MA 16219) and compact spike (MA 17648) were isolated from M₃ progeny of durum wheat cultivar, Altaiskaya Niva, mutagenized with chemical mutagens. The chromosomal locations of the genes involved were determined by the use of a complete set of D-genome disomic substitutions in durum cultivar, Langdon. The gene for sphaerococcoid grain, s ¹⁶²¹⁹ , was allelic to S2, located in the centromeric region of chromosome 3B in hexaploid wheat. The gene for compact spike, C ¹⁷⁶⁴⁸ , was located on chromosome 5AL distal to the Q locus. Using microsatellite markers, C ¹⁷⁶⁴⁸ and awn inhibitor B1 were located in the F₂ of LD222 × MA17648. The gene order was Xbarc319—C ¹⁷⁶⁴⁸ —Xgwm179—Xgwm126—Xgwm291—B1.     

Bacterial degradation of antibiotic residues in marine fish farm sediments of Uranouchi Bay and phylogenetic analysis of antibiotic-degrading bacteria using 16S rDNA sequences

ABSTRACT:   Antibiotic residues in marine sediments of fish farms negatively influence microbial ecologic systems. The microbial degradation of antibiotic residues was experimentally examined in the marine sediments of Uranouchi Bay, to which one of five antibiotics was added. After incubation reducing physical factors, ampicillin, doxycycline, oxytetracycline, and thiamphenicol were significantly degraded, while josamycin maintained most of the initial amounts. The isolates resistant to ampicillin, josamycin, oxytetracycline, or thiamphenicol degraded each antibiotic in wide ranges of degrees, whereas the isolates degrading doxycycline were not obtained. Microbial degradation may contribute to the disappearance of ampicillin, doxycycline, oxytetracycline, and thiamphenicol in the fish farm. In contrast, the disappearance of josamycin would depend on physical factors, but the bacteria degrading josamycin at least exist in the marine sediments. Phylogenetic analysis using 16S rDNA sequences demonstrated that the antibiotic-resistant isolates formed several clusters in the Gram-positive bacterial group, the Flavobacterium–Cytophaga–Bacteroides group, and the proteobacteria subdivisions. The antibiotic-resistant bacterial population would be composed of various species including ubiquitous coastal bacterial groups. Several species of antibiotic resistant bacteria show antibiotic degradation activities, and appear to contribute to the disappearance of antibiotics in Uranouchi Bay.     

Characteristics water balance in paddy fields with pipelines or open channels in Hokkaido

Paddy and Water Environment - Hokkaido is an important agricultural area of Japan. The amount of arable land managed per farming household has been increasing because of the aging of farmers and...     

Effects of hypoxia and glucose-removal condition on muscle contraction of the smooth muscles of porcine urinary bladder

To elucidate the dependence of aerobic energy metabolism and utilization of glucose in contraction of urinary bladder smooth muscle, we investigated the changes in the reduced pyridine nucleotide (PNred) fluorescence, representing glycolysis activity, and determined the phosphocreatine (PCr) and ATP contents of the porcine urinary bladder during contractions induced by high K⁺ or carbachol (CCh) and with and without hypoxia (achieved by bubbling N₂ instead of O₂) or in a glucose-free condition. Hyperosmotic addition of 65 mM KCl (H-65K⁺) and 1 µM CCh induced a phasic contraction followed by a tonic contraction. A glucose-free physiological salt solution (PSS) did not change the subsequent contractile responses to H-65K⁺ and CCh. However, hypoxia significantly attenuated H-65K⁺- and CCh-induced contraction. H-65K⁺ and CCh induced a sustained increase in PNred fluorescence, representing glycolysis activity. Hypoxia enhanced H-65K⁺- and CCh-induced increases in PNred fluorescence, whereas glucose-free PSS decreased these increases, significantly. In the presence of H-65K⁺, hypoxia decreased the PCr and ATP contents; however, the glucose-free PSS did not change the PCr contents. In conclusion, we demonstrated that high K⁺- and CCh-induced contractions depend on aerobic metabolism and that an endogenous substrate may be utilized to maintain muscle contraction in a glucose-free PSS in the porcine urinary bladder.     

Effects of Acidification on Salmonid Spawning Behavior

We studied the effects of acidification on female sexual behavior in brown trout (Salmo trutta) and compared the results with those in hime (land-locked sockeye) salmon (Oncorhynchus nerka) (Kitamura and Ikuta, 2000). The results were similar to those of sockeye salmon. Spawning brown trout were extremely sensitive to the acidity of ambient water, and nest-digging behavior was severely inhibited (p<0.05) by very slight acidification (pH below 6.4). However, there were some differences between the two species. Female trout and salmon showed almost no digging below pH 5.0 and 6.0 (Kitamura and Ikuta, 2000), respectively. When the ambient water was returned to nearly neutral (pH6.6) conditions, digging in hime salmon reappeared in 4 of the 6 fish tested (Kitamura and Ikuta, 2000), whereas digging in brown trout reappeared in all 6 fish tested. The above-mentioned differences in behavioral response between the two species appear to reflect the species difference in terms of vulnerability to acidification (Ikuta et al., 1992). Avoidance of slightly acidic water in selection of spawning site or cessation of spawning behavior in weakly acidic environments may be the most potent cause of the reduction of salmonid populations in the early stages of acidification.     

Determination and Speciation of Aluminum in Environmental Samples by Cation Exchange High-Performance Liquid Chromatography with High Resolution ICP-MS Detection

A cation-exchange high-performance liquid chromatography with high resolution inductively coupled plasma mass spectrometric detection (CE-HPLC/ICP-MS) was developed for the determination and the speciation of aluminum in environmental samples. Three types of aluminum species (AlL_x ^<+2, AlL_x ²⁺, Al³⁺) were separated from one another, and were determined with the present system. The comparison of the present system with an established CE-HPLC with fluorimetric detection using 5-sulfo-8-quinolinol (CE-HPLC/FL) was described. The present system showed better sensitivity for aluminum than CE-HPLC/FL. Moreover, the analytical results for soil extract and lake water samples obtained with both methods were in good agreement with each other.     

Survival time of juvenile pen shell Atrina pectinata (Bivalvia: Pinnidae) in hyposaline water

International Aquatic Research - Survival time of juvenile pen shell Atrina pectinata (shell length&nbsp;≈&nbsp;34&nbsp;mm) exposed to hyposaline water without sediments was...