Cytogenetics of ticks (Acari: Ixodoidea)

Chromosomes and sex determination of 9 species of Haemaphysalis assigned to 4 subgenera are described. H. (tAlloceraea) kitaokai possesses an XX∶XO sex chromosome system with 18 autosomes plus XX in females; 18 plus X in males. H. (Kaiseriana) hystricis has 18 +XX and 18 + XY in females and males, respectively, in most specimens, but a supernumerary chromosome is present in some individuals. A supernumerary chromosome was also observed in 1 male H. (Aborphysalis) formosensis. These two species are the second and third species of ticks reported to have supernumerary chromosomes. H. formosensis, H. (Kaiseriana) bispinosa, H. (Haemaphysalis) campanulata, H. (H.) flava, H. (H.) megaspinosa, H. (H.) japonica, and H. (H.) pentalagi possess 20 autosomes plus 2 sex chromosomes in females and 20+1 sex chromosomes in males. Phylogenetic relationships within the genus Haemaphysalis are briefly discussed.     

Zymographic demonstration of lactate and malate dehydrogenases isoenzymes in the rodent salivary glands

Summary Analysis of lactate and malate dehydrogenase zymograms of rodent salivary glands showed species and organ specific patterns.Lactate dehydrogenase isoenzyme patterns occupied the middle positions in relation to those of skeletal and heart muscle. Activities of the major salivary glands were in the order submaxillary gland>parotid>sublingual gland. Zymogram of the mouse and rat showed LDH₄ and LDH₅ high activity patterns, while that of the rabbit was the fast moving active one. Hamster salivary gland exhibited a neutral type of the former and the latter.Malate dehydrogenase isoenzyme exhibited very similar patterns for the mouse, rat and hamster. Malate dehydrogenase zymogram of rabbit showed 3 active bands, which was different from the other rodents.     

Nucleic Acid Metabolism Involved in Auxin-induced Elongation of Yeast Cells

The following results were obtained using a variant yeast strain, N55, which can respond to the cell-elongating action of auxin. Base analogs of nucleic acids (2-thiouracil, 8-azaguanine, and 5-fluorouracil) inhibited the auxin-induced elongation of yeast cells only when they were added to the preculture prior to auxin treatment. The inhibitory effect of 2-thiouracil and 5-fluorouracil was reversed by uracil and that of 8-azaguanine by guanine. Actino-mycin D inhibited the auxin-induced elongation when given to the culture containing auxin, but not when given to the preculture. The similarity in these respects between yeast and tissues of higher plants is discussed.     

Genetic differentiation among eight color types of the freshwater goby,Rhinogobius brunneus,from western Japan

Genetic differentiation among eight color types of the freshwater goby,Rhinogobius brunneus, from the western part of Japan was investigated by using electrophoretic methods. Four sympatric types (Cross-band, Dark, Cobalt and Large-Dark (A) types) did not share alleles at between one and six loci out of 12 loci tested. No hybrid specimens were found among these types. The average genetic distances among these four types ranged from 0.13 to 0.72, which fall within the range of values among congeneric species of fishes. The average genetic distances among the other four types, Large-Dark (B), Orange, Shinji-Lake and Boso types, were only 0.01 to 0.03, and fall within the range of values among conspecific populations. These results suggest that the former four types are clearly discrete species and the latter four types may be considered as intraspecific variations of a fifth species.     

Generation of neutralization-resistant HIV-1 in vitro due to amino acid interchanges of third hypervariable env region.

Antigenic mutants of HIV-1 were isolated from three plaque-cloned viruses by the resistance of the virus to neutralizing mAb 0.5 beta against V3 domain of viral gp120, when the viruses were passaged in the presence of the antibody. However, when chronically infected MOLT-4 cells were treated with 0.5 beta mAb, recovered viruses from the 0.5 beta-treated cells showed no antigenic changes. The extent of genomic variation among antigenically distinct isolates was examined by nucleotide sequencing, which revealed a few base substitutions in 0.5 beta-binding site of all mutants isolated. The predicted amino acid replacements within 0.5 beta reacting epitope (V3 domain) causing the altered antigenicity were also identified for each of three isolates. Particularly, in one of the mutants, the most conserved Gly-Pro-Gly-Arg region located at the center of the V3 domain was changed to Gly-Gln-Gly-Arg. The radioimmunoprecipitation and synthetic peptide analyses revealed that this Pro320----Gln substitution reduced the binding affinity with 0.5 beta, although other mutations observed in the other mutants did not affect the binding affinity in radioimmunoprecipitation. We also observed that nucleic acid substitutions in the V3 domain occurred frequently in the absence of 0.5 beta mAb during our in vitro acute infection system using MT-4 cells.     

Intravesical treatment of bladder cancer with recombinant human interferon-β

Summary In order to examine its clinical efficacy, recombinant human interferon- (rIFN-) was instilled intravesically into 51 patients with superficial bladder cancer. Ten patients, who received intermittent intravesical instillation at a dose of (3–36) × 10⁶ U rIFN- on days 1–3 every week, showed no response. Thirty-two patients received intravesical instillation at a dose of (3–36) × 10⁶ U every day for 10–20 days. Eight patients showed partial response, indicating an efficacy rate of 25%. Nine patients received divided doses of 18 × 10⁶ U twice a day every day for 10–20 days. Six patients showed partial response, indicating an efficacy rate of 67%. This value was significantly higher than that obtained by administering divided doses. The response to intravesical instillation therapy with rIFN- varies with treatment protocol. Frequent and longer exposure to rIFN- may induce better regression of superficial bladder cancer. Six incidences of side-effects were found in five cases (9.8%): pollakiuria in one, pain on micturition in two, fever in two, and eruption in one case. All of these side-effects were slight and reversible after drug withdrawal. Laboratory tests showed only a few changes with low severity. Thus, rIFN- is potentially a new drug for instillation therapy of superficial bladder cancer, in view of the absence of adverse effects.     

Identification of a common molecular basis for combined 17α-hydroxylase/17,20-lyase deficiency in two Mennonite families

Summary During the course of studies to characterize mutations of the CYP17 gene that cause the 17-hydroxylase-deficient form of congenital adrenal hyperplasia we have discovered two ostensibly unrelated Mennonite families in which affected individuals are homozygous for the same mutation. The defect is a four-base duplication in exon 8 of the CYP17 gene, which alters the reading frame encoding the C-terminal 26 animo acids of cytochrome P450₁₇.     

Primary structure of chicken pituitary prolactin deduced from the cDNA sequence. Conserved and specific amino acid residues in the domains of the prolactins

The perform of chicken prolactin (PRL) deduced from the cDNA sequence contains a signal peptide of 30 amino acid residues followed by a mature PRL of 199 residues. Chicken PRL shows 77, 68, 67, 58, and 31% identity of amino acid sequence with whale, human, ovine, rat, and salmon PRLs, respectively. Elucidation of the primary structure of avian PRL enabled extended analysis of the specific and conserved amino acid residues and domains of the PRL molecules. The mammalian, teleostean, and avian PRLs share 32 common residues, and these conserved residues are observed to cluster in four distinct domains (PD1 to PD4), corresponding to four of five conserved domains of the growth hormones. Of the 32 residues, 8 residues in the PD2 and PD4 domains, including 4 cysteines, are conserved by other members of the growth hormone family, which indicates that these 8 residues may be essential for common structural features of the gene family. On the other hand, 13 other residues distributed among all four domains are conserved almost exclusively in the PRLs, suggesting that these residues are indispensable for specific binding of the PRLs to their receptors.     

Cytochrome P-450 and chromosome damage by cyclophosphamide in LEC strain rats predisposed to hereditary hepatitis and liver cancer

LEC strain rats predisposed to hereditary hepatitis and liver cancer were examined for hepatic drug-metabolizing ability and the inducibility of chromosome damage by cyclophosphamide (CP) in somatic cells. Whereas the hepatic cytochrome P-450 contents and the activities of cytochrome P-450-catalyzed monooxygenases were lower in females than in males of both LEC and control LEA strains, male LEC rats exhibited significantly reduced cytochrome P-450 contents and monooxygenase activities compared with male LEA rats. When exposed to CP, a promutagen/procarcinogen requiring P-450-dependent metabolic activation, the frequencies of chromosome aberrations and sister-chromatid exchanges (SCEs) in bone marrow cells tended to be lower in females than in males of each strain and lower in LEC than in LEA rats of the same sex. In particular, the CP-induced SCEs were substantially lower in LEC rats. However, no such sex and strain differences were found in the SCE frequencies in regenerating hepatocytes of partially hepatectomized rats exposed to CP.