Cytotoxicity of Streptococcus agalactiae secretory protein on tilapia cultured cells

Streptococcus agalactiae secrete virulence factors believed to be able of killing host tissues, especially under elevated water temperature. A direct effect of S. agalactiae secretory products on tilapia cells was tested on the tilapia kidney (TK-1) cell culture. The bacteria were cultured under four different temperature levels: 22, 29, 32 and 37°C; the cell-free portion was processed through SDS-PAGE; and distinct bands were identified by LC-MS/MS. At least, three virulence factors were identified, Bsp, PcsB and CAMP factor, with increasing levels as the cultured temperature rose. Expressions of bsp, pcsB and cfb were also up-regulated with the rising of the temperature in S. agalactiae culture. The supernatant from the bacteria cultured under specified temperatures was added into TK-1 cell-cultured wells. Morphological damage and mortality of the cultured cells, as determined by MTT method, were increased progressively from the supernatant treatment according to the rise of temperature in S. agalactiae culture. This study suggests that the production of the three virulence factors of S. agalactiae reported herein is temperature-dependent, and it is likely that CAMP factor directly kills the TK-1 cells since the other two types of protein are involved in S. agalactiae cell division and the bacterial adherence to host tissues.     

Bacterial Blight of Welsh Onion : A New Disease Caused by Xanthomonas campestris pv. allii pv. nov.

In June of 1998, a new bacterial disease was observed on Welsh onion in Okinawa Prefecture, Japan. Infected plants in nursery boxes were stunted with tip dieback, and heavily infected plants died. In fields, the disease appeared on leaves as irregular gray spots or elliptical spots with creases in the center. These spots enlarged and spread rapidly continued cloudy or rainy weather, and formed blight lesions on outer leaves. Yellow mucoid bacterial colonies were consistently isolated from these lesions. The causal bacterium was identified as a pathovar of Xanthomonas campestris on the basis of bacteriological properties. The bacterium was pathogenic to Welsh onion, onion, but nonpathogenic to chive, Chinese chive and hyacinth. Of Liliaceae plants, which contain Welsh onion and onion, only hyacinth has been reported as a host for the genus Xanthomonas, namely X. campestris pv. hyacinthi. However, strains of X. campestris pv. hyacinthi were not pathogenic against either Welsh onion or onion. From these results, the bacterium isolated from Welsh onion is considered to be a new pathovar of X. campestris, and the name of X. campestris pv. allii pv. nov. is proposed. A strain MAFF 311173 is designated as the pathotype strain. Received 29 March 2000/ Accepted in revised form 4 July 2000     

Molecular and serological prevalence of Babesia bovis and Babesia bigemina in water buffaloes in the northeast region of Thailand

Bovine babesiosis is a tick-transmitted hemoprotozoan disease that is mainly caused by Babesia bovis and Babesia bigemina and is characterized by significant morbidity and mortality worldwide. The disease is widespread in the northeastern region of Thailand, where an increasingly large part of the livestock is composed of water buffaloes. The present study was therefore conducted to investigate the epidemiological distribution of B. bovis and B. bigemina in water buffaloes in the northeastern region of Thailand. A total of 305 buffalo blood samples were randomly collected from five provinces and simultaneously analyzed by the nested PCR (nPCR) assay, ELISA, and IFAT techniques. The overall prevalence of B. bovis and B. bigemina was 11.2% and 3.6% by nPCR, 14.7% and 5.9% by ELISA, and 16.8% and 5.6% by IFAT, respectively. The high concordance between the molecular and the serological detection tests revealed the specificity and sensitivity of the diagnostic assays used for the detection of infection as well as the endemic stability status of the parasites in the surveyed areas. Statistically significant differences in the prevalence of the two infections were observed on the basis of age and location but not gender. Our data provide valuable information regarding the epidemiology of B. bovis and B. bigemina infection in water buffaloes in the northeastern region of Thailand which will likely be very beneficial for management and control programs of this disease.     

Mycoplasma ovis detected in free-living Japanese serows, Capricornis crispus

Nineteen blood samples collected from free-ranging wild Japanese serows, Capricornis crispus, between 2006 and 2008 in Iwate prefecture were examined for the hemoplasma infection by real-time PCR targeting the 16S rRNA gene. Five (26.3%) out of the 19 samples were positive in real-time PCR with an average melting temperature at 85.18 °C. The positive samples in the real-time PCR were reconfirmed by conventional PCR, and one of them was successful for direct DNA sequencing. The nucleotide sequence of the 16S rRNA gene of the representative stain was identical to that of Mycoplasma ovis. This was the first demonstration of hemotropic mycoplasma infections among the free-living Japanese serows in Japan.     

Morphology of placentome in Korean water deer Hydropotes inermis argropus

The placenta of the Korean water deer was anatomically examined to accumulate basic information regarding its reproductive system. The convex placentomes with five to nine well-developed pedicles were observed in the whole uterine horns, and therefore, the placenta was classified as oligocotyledonary. The evidence indicating the migration of binucleate cells (BNCs) from trophectoderm to the uterine epithelium led to the histological classification of the placenta as synepitheliochorial. The number of fetuses was markedly higher than that in other ruminant species. However, the number of placentomes was found to be similar to the other Cervidae species. Therefore, these results suggest that the Korean water deer may possess special mechanisms or structures at the fetus attachment site to maintain this unusally high number of fetuses.     

Genes expressed in Japanese flounder <Emphasis Type="Italic">Paralichthys olivaceus</Emphasis> spleen: analysis of genes involved in immune function

ABSTRACT:   Expressed sequence tag (EST) analysis is an efficient tool for gene discovery and for profiling gene expression. A cDNA library developed from messenger RNA of the Japanese flounder, Paralichthys olivaceus spleen was constructed by directional cloning, in order to isolate functional genes involved in immunity in fish. A total of 1010 ESTs from the library were sequenced and compared with sequences in the GenBank database. Of the 1010 ESTs, 618 ESTs (61%) were identified as being homologous with known genes from many organisms by BLAST searches, whereas 392 (39%) appeared to be unknown and are likely to represent newly described genes. Of the identified genes, 105 (17%) encoded proteins associated with cell/organism defence and homeostasis. Of these 105 genes, 21 were identified for the first time in Japanese flounder. These included macrophage inflammatory protein (MIP)-3 α, granulin-A, novel immune-type receptor (NITR), interferon regulatory factor (IRF)-10, presenilin-like protein-2, and antizyme inhibitor. A comparison of ESTs derived from spleen, kidney, liver and leukocytes suggested that expression of immune-related genes in different tissues, organs, or cells are different.