Therapeutic effect of modified oligopeptides from the beetle Allomyrina dichotoma on methicillin-resistant Staphylococcus aureus (MRSA) infection in mice

Anti-bacterial activity of two synthesized oligopeptides, RLYLRIGRR-NH2 (peptide A) and RLRLRIGRR-NH2 (peptide B), both which based on a putative active site of defensin, an anti-bacterial peptide from the beetle Allomyrina dichotoma, was examined by macroscopic and histopathologic assessment during the course of infection in mice inoculated with methicillin-resistant Staphylococcus aureus (MRSA) in vivo. Both peptides A and B decreased the mortality of mice inoculated with MRSA. Peptides A and B decreased the macroscopical and histopathological lesions by MRSA infection in mice even seven days after the challenge. The anti-bacterial activity of peptides A and B has a therapeutic effect on MRSA infection in mice even seven days after being challenged.     

Canine tyrosine hydroxylase (TH) gene and dopamine beta -hydroxylase (DBH) gene: their sequences, genetic polymorphisms, and diversities among five different dog breeds

Dopamine and noradrenaline are catecholamine neurotransmitters that are produced by biosynthetic enzymes such as tyrosine hydroxylase (TH) and dopamine beta -hydroxylase (DBH). As a first step to elucidate the genetic background of canine behavioral traits, we selected these genes as targets and sequenced these canine genes, and found that both were highly homologous with those of human beings. Then brain cDNAs derived from ten unrelated Beagles were used to search for polymorphisms in these genes. Four single nucleotide polymorphisms (SNPs) (C97T, G168A, G180A and C264T), one of which (C97T) will cause amino acid substitution in the TH gene, and two SNPs (C789A and A1819G), both of which will cause amino acid substitutions in the DBH gene were identified. The allelic frequencies among five dog breeds (47 Golden Retrievers, 41 Labrador Retrievers, 40 Malteses, 26 Miniature Schnauzers, and 39 Shibas) were examined and found to have significant variation between them with regards to all these SNPs, except for C97T in the TH gene and A1819G in the DBH gene. The polymorphisms of C97T and A1819G were found only in the Shiba. The present results suggest that the polymorphisms of the genes encoding catecholamine biosynthetic enzymes may become important markers for examining the genetic background of behavioral characteristics in dogs.     

<Emphasis Type="Italic">Helicobasidium mompa</Emphasis> isolates from sweet potato in continuous monoculture fields

 Isolates of the violet root rot fungus Helicobasidium mompa were collected from herbaceous and tree plants. Their host preference was studied by inoculation experiments using carrots, sweet potatoes, and apple stocks. It was found that sweet potato isolates from Kyushu produced infection cushions on carrots and sweet potatoes but not on apple stocks. Other isolates did not show host preference. Sweet potato isolates were also characterized by ready hyphal mass (sclerotium) production. They were thought to have adapted to the habitat with high disturbance by annual tillage. Received: July 15, 2002 / Accepted: September 26, 2002     

Inoculation of Lupinus luteus with White Root Rot Fungus, Rosellinia necatrix, to Estimate Virulence

An inoculation method using Lupinus luteus was developed for estimating virulence of isolates of the white root rot fungus, Rosellinia necatrix Prillieux. Fungal cultures grown on pieces of mulberry twigs were placed in contact with the hypocotyl of 3-week-old seedlings growing in pots of soil. Disease development was uniform and reproducible in repeated experiments. Of 24 isolates with double-stranded RNA, eight were weakly virulent. This method is useful throughout the year for estimating virulence of many isolates of the fungus and for screening for hypovirulent isolates. Received 2 March 2001/ Accepted in revised form 25 May 2001     

Susceptibility to tuberculosis: composition of tuberculous granulomas in Thorbecke and outbred New Zealand White rabbits

We sought to characterize the lung cellular immune responses to inhaled Mycobacterium tuberculosis (Mtb) of the susceptible inbred Thorbecke rabbit (the genomically sequenced strain, now unavailable) and compare it to outbred, Mtb-resistant, New Zealand White rabbits. Using Mtb CDC1551, we confirmed that the inbred rabbits allowed establishment of infection with this low virulence strain, compared to poor establishment in outbred rabbits. With a more virulent strain, Mtb Erdman, that establishes infection well in both rabbit strains, we analyzed granulomas from rabbit lungs 5 weeks after aerosol infection. The lung granulomas of inbred rabbits had significantly higher frequencies of cells expressing MHC Class II and CD11b, and lower frequencies of CD8+ T cells than the outbred controls. Macrophage-sized cells expressing MHC Class II in inbred rabbit granulomas showed significantly decreased intensity of expression, suggesting impaired maturation. Although the inbred dermal tuberculin reactions were decreased, the in vitro IFN-gamma mRNA responses of hilar node lymphocytes to tuberculin were higher than those of outbred rabbits. Further delineation of the outbred rabbit's resistant immune response to Mtb infection is warranted.     

Localization of the candidate genes ELOVL5 and SCD1 for 'male effect' pheromone synthesis in goats (Capra hircus)

The 'male effect' is a well-known phenomenon in female sheep and goats, whereby pheromone-induced activation of reproductive function occurs. In a previous study, we showed that the genes for elongation of long-chain fatty acids family member 5 (ELOVL5) and stearoyl-CoA desaturase 1 (SCD1) increased their expression significantly, concomitant with induction of pheromone synthesis. Therefore, these genes were considered to be prime candidate genes for pheromone synthesis. In the present study, we performed in situ hybridization to investigate where these two genes are expressed in goat skin. Strong positive signals were detected for both genes in the head skin of the male goat, which is the main site of pheromone production, and were mainly in the basal layer of the sebaceous gland cells, with the remaining cells showing negligible signals. None of the cells in the rump skin of the male goat or the head skin of the orchidectomized goat, neither of which produce pheromone, exhibited strong positive signals. The present study demonstrates that expression of these two candidate genes for pheromone synthesis is primarily localized in the sebaceous glands of the pheromone-producing skin region.     

Development of novel SNP system for individual and pedigree control in a Japanese Black cattle population using whole‐genome genotyping assay

Individual identification and parentage analysis using DNA markers are essential for assuring food identity and managing livestock population. The objective of this study was to develop a single nucleotide polymorphism (SNP) panel system for individual effective identification and parentage testing in a Japanese Black cattle population using BovineSNP50 BeadChip. On the basis of SNP frequencies, 60 unlinked informative SNPs were finally selected as candidate markers. The allelic frequencies for each SNP were estimated using additional individuals by PCR‐RFLP (restriction fragment length polymorphism). A total of 87 SNP markers added in conjunction with previously developed 27 SNPs were evaluated to assess the utility of the test. The estimated identity power was 2.01 × 10^?34. Parentage exclusion probabilities, when both suspected parents' genotypes were known and when only one suspected parent was genotyped, were estimated as 0.99999997 and 0.99998010, respectively. This developed SNP panel was quite powerful and could successfully exclude false sires with a probability of >0.9999 even if the dam's genotype information was not obtained. The SNP system would contribute to management of the beef industry in Japan.     

Effects of chitin degradation products N-acetylglucosamine and N,Nʹ-diacetylchitobiose on chitinase activity and bacterial community structure in an incubated upland soil

ABSTRACT

Chitin, which is the polymer of N-acetylglucosamine (GlcNAc) linked by β1,4 glycoside bonds, has been reported as a soil amendment to mitigate plant soil diseases, increasing the population of chitin-degrading bacteria, and chitinolytic enzymatic activity in the soil. In some chitin-degrading bacteria, whose chitinolytic systems have been intensively studied, the chitin degradation product N,N?-diacetylchitobiose {(GlcNAc)₂} induces expression of genes for chitinases whereas GlcNAc does not. To evaluate the effects of these mono- and disaccharides on the population and activity of chitinolytic bacteria in soil, we investigated the chitinolytic enzyme activity and bacterial community structure in an incubated upland soil supplemented with GlcNAc or (GlcNAc)₂. The added GlcNAc and (GlcNAc)₂ (2 mg g^?1) were consumed within 1 d when incubated at 25°C. Chitinase activity was induced by (GlcNAc)₂ and chitin after 1-d and 7-d incubation, respectively, but not by GlcNAc. N-acetylglucosaminidase (GlcNAcase) activity was induced by GlcNAc but was lower than those by (GlcNAc)₂ and chitin. Amplicon sequencing analysis targeting 16S rRNA genes demonstrated that both GlcNAc and (GlcNAc)₂ significantly increased the rate of the order Bacillales, but the compositions of Bacillales differed from each other: the family Planococcaceae significantly increased in either GlcNAc- or (GlcNAc)₂-added soil, but the genera Bacillus and Paenibacillus were increased mainly by GlcNAc and (GlcNAc)₂, respectively. The family Streptomycetaceae of the order Actinomycetales was significantly increased by (GlcNAc)₂ and chitin, but GlcNAc did not. Thus, GlcNAc and (GlcNAc)₂, which were promptly consumed in the incubated soil, indicated partly similar but distinctive effects on chitinolytic enzyme activity and bacterial communities. Both aminosugars increased GlcNAcase activity and the population size of Planococcaceae. GlcNAc increased Bacillus. Chitinase activity and the populations of Paenibacillus and Streptomycetaceae, a number of strains of which are known as potent chitin-degraders, were increased by (GlcNAc)₂, but not by GlcNAc.     

Natural foods utilized by Nile tilapia, <Emphasis Type="Italic">Oreochromis niloticus</Emphasis>, in fertilizer-based fish ponds in Lao PDR identified through stable isotope analysis

Nile tilapia, Oreochromis niloticus, is one of the most popular freshwater aquaculture species in developing countries. Although formulated feed provides higher fish yield, it is expensive. Therefore, fertilizer-based fish culture using natural food sources is generally implemented in developing countries. The aim of this study was to identify the major natural foods contributing to tilapia growth in fertilizer-based fish ponds. The stomach contents of tilapia in a fertilizer-based fish pond in Lao PDR were analyzed to estimate their feeding behaviors; stable isotope ratios of carbon and nitrogen in the potential food organisms and suspended solids were measured and compared with the ratios in the fish muscle tissues. Further, the feed efficiency of chironomid larvae was compared with that of chlorella and formulated feed in a laboratory feeding experiment. Consequently, chironomid larvae were identified as the main contributors to tilapia growth in the fertilizer-based fish pond. In conclusion, benthic larvae of insects belonging to the family Chironomidae are confirmed to be a natural food source for tilapia in the fertilizer-based fish pond.