Disease Resistance of Tissue-cultured Seedlings of Rhododendron after Treatment with Streptomyces sp. R-5

An endophytic actinomycete, Streptomyces sp. R-5, which had been isolated from a field-grown rhododendron plant, was used to protect rhododendron seedlings in tissue culture from Pestalotia disease caused by Pestalotiopsis sydowiana. R-5 had intense antagonistic activity against P. sydowiana without adversely affecting the seedlings in glass flasks. A suspension of R-5 was spread on the surface of the multiplication medium in glass flasks in which seedlings were growing. Ten days later, the 4th upper leaf of seedlings was inoculated with P. sydowiana and incubated for 14 days. In controls untreated with R-5, substrate mycelia of P. sydowiana grew on all leaves and stems above and below the 4th leaf within 2–3 days of inoculation. Such growth resulted in the wilting death of 54% of seedlings by 14 days. In contrast, only the inoculated leaves turned brown in ca. 90% of seedlings growing on medium treated with R-5. None of these seedlings died. Thus, treatment of the medium surface with R-5 efficiently protects the seedlings from infection by P. sydowiana. Scanning electron microscopy revealed that substrate mycelia of R-5 grew on and beneath the cuticle of leaves of the treated seedlings. Fluorescent microscopy showed that R-5 was also inside the leaves. Received 8 June 2001/ Accepted in revised form 4 July 2001     

Ammonia channel couples glutaminase with transamidase reactions in GatCAB

The formation of glutaminyl transfer RNA (Gln-tRNA(Gln)) differs among the three domains of life. Most bacteria employ an indirect pathway to produce Gln-tRNA(Gln) by a heterotrimeric glutamine amidotransferase CAB (GatCAB) that acts on the misacylated Glu-tRNA(Gln). Here, we describe a series of crystal structures of intact GatCAB from Staphylococcus aureus in the apo form and in the complexes with glutamine, asparagine, Mn2+, and adenosine triphosphate analog. Two identified catalytic centers for the glutaminase and transamidase reactions are markedly distant but connected by a hydrophilic ammonia channel 30 A in length. Further, we show that the first U-A base pair in the acceptor stem and the D loop of tRNA(Gln) serve as identity elements essential for discrimination by GatCAB and propose a complete model for the overall concerted reactions to synthesize Gln-tRNA(Gln).     

Color development of proanthocyanidins in vanillin-hydrochloric acid reaction

The influence of proanthocyanidin (PA) structures contained in bark on color development in the vanillin-hydrochloric acid (V-HCl) method used widely as a quantitative method for measuring PA were examined. The maximal absorption wavelength was different in terms of the bark from which the PA was obtained. Phenyl nucleus (resorcinol, phloroglucinol) constituting the A-ring of PA reacts with vanillin to produce the color. The maximal absorption wavelengths of the solutions from synthesized procyanidin and profisetinidin were 500 and 540 nm, respectively, indicating that the color tone differs in the V-HCl method based on the hydroxylation patterns of the A-ring. The colored solution of (+)-catechin with vanillin was dialyzed, and the resulting product (C-VC) was analyzed by gel permeation chromatography and ¹H nuclear magnetic resonance. It was found that C-VC was a polymer complex consisting of 9mol (+)-catechin moieties and 10mol vanillin moieties. It was presumed that the cationized vanillin molecules that do not combine with (+)-catechin play an important role on color development in the presence of C-VC.This study was presented at the 44th and 45th Annual Meetings of The Japan Wood Research Society, Nara and Tokyo, April 1994 and April 1995     

Induced Ovarian Maturation of Penaeus vannamei by Implantation of Lobster Ganglion

Induction of ovarian maturation in Penaeus vannamei , by implantation of ganglion prepared from female lobster, Homarus americanus , with developing ovaries was investigated under tank culture conditions. Four of six females with thoracic ganglion implants were maturing while only two of thirteen females of the control groups with abdominal ganglion or no implant matured. Two ripe stage V were found 18 days after implantation of lobster's thoracic ganglion. This indicates that ovarian maturation of P. vannumei in tanks can be induced and accelerated by implantation of thoracic ganglion prepared from maturing females of another species. Ovarian maturation may be induced by a gonad-stimulating hormone, secreted by the thoracic ganglion of maturing females. This gonnd-stimdating hormone is not species specific in activity in the shrimp and lobster.     

Diffuse global granulomatous glomerulonephritis in a pig

Diffuse global granulomatous glomerulonephritis with unique morphological characters was detected in a pig. The structure of the basement membrane of glomerular tufts was destroyed in almost all glomeruli. Various inflammatory cells consisted mainly of macrophages infiltrated severely into the glomerular tuft and the Bowman's space of and extended to the periglomerular interstitium. Periarteritis with fibrinoid necrosis was occasionally seen in the arterioles and small arteries running through the renal parenchyma and pelvis. In the present case, the results of either the immunohistochemical reactions to the antigens against PRRSV or PCV-2 or Ziel-Neelsen staining for acid-fast bacilli were negative and no pathogenic bacteria were cultured.     

Deformed liver with prominent proliferation of bile ducts in a pig

A deformed liver characterized by remarkable ductular proliferation was encountered in a 6-month-old pig and examined histopathologically. The most conspicuous histopathologic change was a mild to severe ductular proliferation in the interlobular areas without any degenerative changes of cholangiolar epithelial cells or hepatocytes. Fibrotic changes and reconstruction of the lobule were not found. Morphological evidence of intrahepatic and extrahepatic cholestasis was lacking. Other characteristics were deformity with displacement of the gall bladder, irregular shape and size of lobules, and structural abnormality of large-sized vessels. The severe ductular proliferation was considered to be due to structural malformations of the excretion channel of bile.     

Tissue retention and adverse reaction after intravenous injection of hematoporphyrin derivatives in dogs

We evaluated changes in hematology and chemical profile, and the tissue retention of hematoporphyrin derivative (HpD) following the intravenous injection in dogs. HpD at concentrations of 1, 5, 10, and 15 mg/kg was intravenously injected to 16 dogs (n=4 each) and complete blood count (CBC) and blood chemistry were performed on days 1, 3, 5, and 7 after the injection. To examine tissue retention, HpD (5 mg/kg) was administered to 15 dogs and 3 dogs were euthanized on days 1, 2, 7, 14, and 28 after the injection, respectively, to collect the skin, muscle, small intestine, spleen, kidney and liver as tissue samples. There were no significant changes in CBC and blood chemical profile except for an increase in LDH concentrations in dogs given 10 and 15 mg/kg of HpD at day 3. The levels of HpD retention in the tissues were ranked in the following order: liver > kidney > spleen > intestine > muscle > skin.     

Identification of genotypes of Giardia intestinalis isolates from dogs in Japan by direct sequencing of the PCR amplified glutamate dehydrogenase gene

Giardia has been detected in domestic dogs in Japan, but the genotype of isolates has remained unclear because identification has relied on conventional microscopy. Here we tried to identify the genotypes of four isolates from dogs in Japan by direct sequencing of the PCR amplified Giardia glutamate dehydrogenase (GDH) gene. The primer pair GDHF3 and GDHB5, targeting the GDH gene, was designed to prime a region of the GDH gene sequence conserved in the strains found to have the dog-specific genotype. The specific PCR product (approximately 220 bp), amplified with this primer pair, was only observed when Giardia DNA was used as the template. The sequences of the diagnostic fragments were identical among the isolates from dogs, and were differed by 15 bp or 1 bp from the strains, which were found to be the dog-specific genotypes, Assemblage C or D respectively. To verify the identity of the amplified DNA, a phylogenetic analysis was performed. Consequently, the sequence of the isolates from dogs clearly clustered with the strain found to be Assemblage D with neighbor-joining analyses. Therefore, all the isolates from dogs examined were identified as the dog-specific genotype, Assemblage D. In the present study, we revealed the genotype of Giardia isolates in Japan, and showed that direct sequencing of the PCR product amplified with the primer pair GDHF3 and GDHB5 was a useful tool for distinguishing between the zoonotic and dog-specific genotypes.