Spread of HTLV-I between lymphocytes by virus-induced polarization of the cytoskeleton

Cell contact is required for efficient transmission of human T cell leukemia virus- type 1 (HTLV-I) between cells and between individuals, because naturally infected lymphocytes produce virtually no cell-free infectious HTLV-I particles. However, the mechanism of cell-to-cell spread of HTLV-I is not understood. We show here that cell contact rapidly induces polarization of the cytoskeleton of the infected cell to the cell-cell junction. HTLV-I core (Gag protein) complexes and the HTLV-I genome accumulate at the cell-cell junction and are then transferred to the uninfected cell. Other lymphotropic viruses, such as HIV-1, may similarly subvert normal T cell physiology to allow efficient propagation between cells.     

Mast cell MMP-9 production enhanced by bacterial lipopolysaccharide

Although mast cells contribute to host protective immunity against bacterial infections, the exact mechanism of their recruitment at the affected site has been unclear. Recently, we have reported that both mouse and human mast cells are capable of producing matrix metalloproteinase (MMP)-9, a matrix-degrading enzyme necessary for leukocyte transmigration. Here, we demonstrated that bacterial lipopolysaccharide (LPS) enhanced MMP-9 production of mouse bone marrow derived-cultured mast cells. This action of LPS was partially suppressed by the pretreatment of cultured mast cells with a protein kinase C (PKC) inhibitor, indicating the possible involvement of PKC signaling pathways in the production of MMP-9 by LPS. Thus, these suggest the upregulation of mast cell MMP-9 by bacterial components, thereby resulting in their migration at the affected site.     

Effects of ammonium chloride-induced acidosis on oxidative metabolism in liver mitochondria of chicks

The present studies were undertaken to characterise oxidative metabolism with diverse substrates in hepatic mitochondria of acidotic chicks. Metabolic acidosis was experimentally induced by replacement of drinking water with ammonium chloride solution (15 g/l) for 5 d. State 3 oxidation rates in liver mitochondria were significantly reduced in acidotic chicks only for pyruvate and glutamate as substrates requiring complex I, III and IV of the electron transport chain, while they were not changed for either succinate-requiring complexes II, III and IV, ascorbate+TMPD-requiring complex IV, or alpha-ketoglutarate requiring complexes I, III and IV. It can be concluded that the impairment of oxidation rate was substrate-specific in liver mitochondria of acidotic animals and not associated with functional damage of the respiratory chain in mitochondria. Possible reasons for the reductions in oxidation rate with pyruvate and glutamate are discussed.     

Changes in platelet life span in dogs with mitral valve regurgitation

Platelet life span was measured in dogs with experimentally-induced mitral regurgitation (MR) by using an in vitro whole-blood biotinylation technique to evaluate the effects of shear stress induced by MR. Mitral regurgitation was created in healthy dogs by ablation of the mitral valve chordae tendineae. Mitral regurgitation was identified by auscultation and postoperative color Doppler echocardiography. Platelets were biotinylated. and derivatized blood was reinfused into the dogs. Biotinylated platelet disappearance was measured over time to determine platelet life span. Pre- and postablation platelet life span was compared in each dog. Platelet life span was shorter in dogs with experimentally induced MR. Shear stress from MR was postulated to shorten platelet life span. Alternations in platelet function and life span may contribute to the progression of cardiovascular disease in dogs with MR. Further studies are required to determine if platelet dysfunction is related to disease progression in these patients.     

Prevalence of Bartonella henselae, Bartonella clarridgeiae and the 16S rRNA gene types of Bartonella henselae among pet cats in Japan

The authors investigated bacteriologically the prevalence of Bartonella infection among 690 pet cats derived from 10 private animal hospitals in six cities (Sapporo, Hokkaido Prefecture; Sendai, Miyagi Prefecture; Joetsu, Niigata Prefecture; Fujisawa, Kanagawa Prefecutre; Kyoto, Kyoto Prefecture; Sanda, Hyogo Prefecutre) and 4 counties (Mishima, Osaka Prefecture; Hikawa, Shimane Prefecture; Aira, Kagoshima Prefecture; Shimajiri, Okinawa Prefecture) located from the north to the south of Japan. Bartonella species were isolated from 7.2% (50/690) of all the cats examined. No Bartonella species were isolated from the cats in Sapporo or Sendai. The isolation rate varied from 2% in Joetsu and Sanda to 20% in Shimajiri. Bartonella clarridgeiae was isolated from two of 50 cats in Kyoto, three of 50 in Mishima and one of 50 in Shimajiri, but not in cats from the other cities or counties. Though the cats of Joetsu, Fujisawa, Kyoto, Sanda, Aira and Shimajiri were infected with either B. henselae or B. clarridgeiae, one of eight infected cats in Mishima was harboring both Bartonella species. Type I of 16S rRNA gene was the predominant type among the isolates of B. henselae, but only one isolate derived from Shimajiri was found to be of type II. Prevalence of B. clarridgeiae and the 16S rRNA gene type of B. henselae among cats in Japan was demonstrated for the first time in this investigation.     

The quality and maturation of bitch oocytes recovered from ovaries by the slicing method

Oocytes were recovered from bitch ovaries at various stages of the estrous cycle by the slicing method. The proportion of Grade A oocytes (darkly pigmented and surrounded in part, or whole, by dense layers of cumulus cells) were counted. Only Grade A oocytes were cultured in TCM199 supplemented with 5% fetal calf serum for evaluation of meiotic competence. There were no significant differences in the total number of oocytes or the proportion of Grade A oocytes that were recovered from bitches at various stages of the estrous cycle. Only 11% of the oocytes reached metaphase II (MII) at 72 hr after initiation of maturation culture. However, the proportions of oocytes reaching MII did not increase with culturing for up to 120 hr.     

Geographical variation of mandible size and shape in the Japanese wild pig (Sus scrofa leucomystax)

The mandibles of the Japanese wild pigs (Sus scrofa leucomystax) from various geographical locations, which have been stored in the University of Tokyo and National Science Museum, Tokyo were examined. The mandibles from northern localities were larger in size than those from southern localities. The Oita population was significantly smaller than the Honshu populations. The Mie population was smaller than the Hyogo population in length from the angle of the mandible. In the multivariate analysis, the Kyushu populations could be obviously distinguished from the Honshu populations in the principal component charts. However, each Honshu population did not show the locality-specific distribution of the principal component plots.     

Reversal of oncogenesis by the expression of a major histocompatibility complex class I gene

The classical transplantation antigens (the major histocompatibility complex class I antigens) play a key role in host defense against cells expressing foreign antigens. Several naturally occurring tumors and virally transformed cells show an overall suppression of these surface antigens. Since the class I molecules are required in the presentation of neoantigens on tumor cells to the cytotoxic T lymphocytes, their absence from the cell surface may lead to the escape of these tumors from immunosurveillance. To test this possibility, a functional class I gene was transfected into human adenovirus 12-transformed mouse cells that do not express detectable levels of class I antigens; the transformants were tested for expression of the transfected gene and for changes in oncogenicity. The expression of a single class I gene, introduced by DNA-mediated gene transfer into highly tumorigenic adenovirus 12-transformed cells, was sufficient to abrogate the oncogenicity of these cells. This finding has important implications for the regulation of the malignant phenotype in certain tumors and for the potential modulation of oncogenicity through derepression of the endogenous class I genes.     

Development of Expressed Sequence Tag (EST)-based Cleaved Amplified Polymorphic Sequence (CAPS) markers of tea plant and their application to cultivar identification

To develop cleaved amplified polymorphic sequence (CAPS) markers for cultivar identification of the tea leaf, 5 primer pairs designed on the basis of genes that encode proteins related to nitrogen assimilation and 26 primer pairs based on expressed sequence tag (EST) sequences of the root of tea plant were screened. From combinations of primer pair and restriction enzyme that showed polymorphism among tea plants, 16 markers were selected and applied to DNA fingerprinting of Japanese tea cultivars. Sixty-three cultivars, except for a bud sport (Kiraka) and its original cultivar (Yabukita) and a pair that was the progeny of the same crossing parent (Harumoegi and Sakimidori), were distinguished from one another. By combining the 16 markers with previously developed CAPS markers and observing the physical appearance, 67 cultivars were distinguishable. The cultivars involve approximately 95% of total tea cultivating area in Japan; therefore, about 95% of tea leaves produced in Japan can be authenticated by labeling their cultivars.