Augmentation of bovine leukemia virus (BLV)-specific lymphocyte proliferation responses in ruminants by inoculation with BLV env-recombinant vaccinia virus: their role in the suppression of BLV replication.

Lymphocyte proliferation responses were investigated in sheep and cattle, in which the replication of bovine leukemia virus (BLV) had been known to be suppressed by inoculation with recombinant vaccinia virus (rVV) expressing BLV envelope glycoprotein (gp60). Enhanced lymphocyte proliferation responses were observed in animals inoculated with rVV, regardless of whether they were naive or BLV carriers. These responses were roughly inversely correlated to the growth of BLV in the peripheral blood leukocytes. In contrast, there was no apparent correlation between humoral immune response and BLV growth. Based on these results, it was suggested that rVV rendered its suppressive effect of BLV replication primarily via augmentation of cell-mediated immunity.     

Molecular cloning and characterisation of 23-kDa piroplasm surface proteins of Theileria sergenti and Theileria buffeli.

The cDNA encoding a 23-kDa piroplasm membrane protein (p23) of Theileria sergenti Chitose (C)-type was isolated and its nucleotide sequence was determined. The gene encodes a polypeptide of 223 aa with a 28 residue N-terminal signal sequence and a hydrophobic, valine-rich, C-terminal transmembrane domain, as deduced from its nucleotide sequence. Southern blot hybridisation analysis proved that p23 gene was a single copy gene and had allelic forms of the gene in the parasite population. By PCR, the open reading frames of T. sergenti Ikeda (I)-type and Theileria buffeli (B)-type p23 were amplified from genomic DNA and their nucleotide sequences were also determined. Comparison of C-type sequence with that of I-type and B-type revealed 90.5% and 93.5% sequence similarity, respectively, at the aa level. These results suggest that a conserved molecule in these benign Theileria spp. could be a candidate antigen for the development of an anti-piroplasm vaccine.     

Genome mining and description of Streptomyces albidus sp. nov., an endophytic actinobacterium with antibacterial potential

Antonie van Leeuwenhoek - An endophytic actinobacterium, strain CAP215T was isolated from the root sample of a native pine tree (Callitris preissii), Adelaide, South Australia. This strain was a...     

Cementum is key to periodontal tissue regeneration: A review on apatite microstructures for creation of novel cementum-based dental implants

The cementum is the outermost layer of hard tissue covering the dentin within the root portion of the teeth. It is the only hard tissue with a specialized structure and function that forms a part of both the teeth and periodontal tissue. As such, cementum is believed to be critical for periodontal tissue regeneration. In this review, we discuss the function and histological structure of the cementum to promote crystal engineering with a biochemical approach in cementum regenerative medicine. We review the microstructure of enamel and bone while discussing the mechanism underlying apatite crystal formation to infer the morphology of cementum apatite crystals and their complex structure with collagen fibers. Finally, the limitations of the current dental implant treatments in clinical practice are explored from the perspective of periodontal tissue regeneration. We anticipate the possibility of advancing periodontal tissue regenerative medicine via cementum regeneration using a combination of material science and biochemical methods.     

Isolation of tumor-associated antigen from sera of bovine leukemia virus-infected cattle

Tumor-associated antigens (TAA) expressed on the surface of enzootic bovine leukemia (EBL) cells were detected and separated from sera of bovine leukemia virus (BLV)-positive cattle using monoclonal antibody-conjugated immunoaffinity matrix. Eluted fraction from these sera showed 3 polypeptides with molecular weights of 70K, 52K, and 30K daltons, and these polypeptides reacted with a monoclonal antibody against TAA. However, only 70K peptide was isolated from culture supernatant of EBL B-cell line. We also tried to examine a reversed passive hemagglutination test to develop a rapid screening system of serum TAA level, but its sensitivity was below the level of detection when EBL sera was applied directly. This is the first report on the existence of tumor antigens in sera from leukemic cattle.     

A calcium requirement for electric field-induced cell shape changes and preferential orientation

C3H/10T1/2 mouse embryo fibroblasts stimulated by a steady electric field (10 V/cm) for 30 min exhibited lamellar retraction on the sides facing the electrodes. Some cells elongated and preferentially oriented with their long axis perpendicular to the field direction. Depletion of external calcium or blockage of calcium influx with lanthanum or the calcium channel blocker D-600 resulted in a reduction of the field-induced response. When external calcium was elevated stepwise from 0 to 10 mM, the field-induced response increased correspondingly. Electric stimulation in the presence of the calcium ionophore A23187 resulted in an increase of spindle-shaped cells with no preferential orientation. This response was blocked by calcium depletion and lanthanum, but not by D-600. The anticalmodulin drug W-13 inhibited the field-induced responses observed in normal buffer as well as in the presence of A23187. Some cell death resulted from prolonged electric field exposure, and the mortality was reduced by calcium depletion, lanthanum or D-600, but was not affected by W-13. We postulate that local calcium influx through channels opened by the electric field produces areas of high intracellular calcium which stimulate the cytoskeletal network to induce lamellar retraction. Prolonged field-induced calcium influx may eventually overcome the cell's mitochondrial calcium-buffer system, leading to necrotic calcification.