Molecular cloning and expression analysis of the mouse<Emphasis Type="Italic"> Spot-2</Emphasis> gene in pituitary development

Mouse Spot-1 is a DNA-binding protein with a domain (His-Thr) encoded by p(CA)n repeats. Spot-1 interacts with the nuclear localization signal (NLS) I of p53 through its His-Thr domain. In this study we describe the cloning and expression patterns of a novel gene encoding a protein containing a His-Thr domain, Spot-2. Spot-2 is exclusively expressed in the pituitary from stage E13.5 to E15.5. Mouse Lhx3 plays a critical role during early organogenesis in the pituitary. The Spot-2 gene appears to be a downstream gene of Lhx3. It is suggested that Spot-2 plays important roles in pituitary development.     

Complete genome sequence and comparative analysis of the industrial microorganism Streptomyces avermitilis

Species of the genus Streptomyces are of major pharmaceutical interest because they synthesize a variety of bioactive secondary metabolites. We have determined the complete nucleotide sequence of the linear chromosome of Streptomyces avermitilis. S. avermitilis produces avermectins, a group of antiparasitic agents used in human and veterinary medicine. The genome contains 9,025,608 bases (average GC content, 70.7%) and encodes at least 7,574 potential open reading frames (ORFs). Thirty-five percent of the ORFs (2,664) constitute 721 paralogous families. Thirty gene clusters related to secondary metabolite biosynthesis were identified, corresponding to 6.6% of the genome. Comparison with Streptomyces coelicolor A3(2) revealed that an internal 6.5-Mb region in the S. avermitilis genome was highly conserved with respect to gene order and content, and contained all known essential genes but showed perfectly asymmetric structure at the oriC center. In contrast, the terminal regions were not conserved and preferentially contained nonessential genes.     

Active site of deblocking aminopeptidase from Pyrococcus horikoshii.

New hyperthermostable aminopeptidase from the hyperthermophilic archaeon Pyrococcus horikoshii has acylamino acid releasing (deblocking) activity for acyl (blocked) peptides. Such an enzyme can be used for N-terminal sequencing of acyl peptides. To clarify the active site of the deblocking aminopeptidase, we prepared three mutants in which one of the three possible active site amino acid residues (Asp or Glu) was replaced with their amide derivatives. Activity and cobalt ion dependence of these mutants were examined and compared with those of the native enzyme. The results suggest that all the three possible residues (Asp173, Glu205, and Glu206) participate in the catalytic activity through binding with the cobalt ion.     

Internal Spatiotemporal Population Dynamics of Infection with Three Wolbachia Strains in the Adzuki Bean Beetle, Callosobruchus chinensis (Coleoptera: Bruchidae)

The adzuki bean beetle, Callosobruchus chinensis, is infected with three distinct lineages of endosymbiotic bacteria belonging to the genus Wolbachia, which were designated wBruCon, wBruOri, and wBruAus. In an attempt to understand the mechanisms underlying the infection with these three organisms, the spatiotemporal infection dynamics of the three Wolbachia strains was investigated in detail by using a quantitative PCR technique. During the development of C. chinensis, the wBruCon, wBruOri, and wBruAus infection levels consistently increased but the growth patterns were different. The levels of infection plateaued at the pupal stage at approximately 3 × 10⁸, 2 × 10⁸, and 5 × 10⁷ wsp copy equivalents per insect for wBruCon, wBruOri, and wBruAus, respectively. At the whole-insect level, the population densities of the three Wolbachia types did not show remarkable differences between adult males and females. At the tissue level, however, the total densities and relative levels of the three Wolbachia types varied significantly when different tissues and organs were compared and when the same tissues derived from males and females were compared. The histological data obtained by in situ hybridization and electron microscopy were concordant with the results of quantitative PCR analyses. Based on the histological data and the peculiar Wolbachia composition commonly found in nurse tissues and oocytes, we suggest that the Wolbachia strains are vertically transmitted to oocytes not directly, but by way of nurse tissue. On the basis of our results, we discuss interactions among the three coinfecting Wolbachia types, reproductive strategies of Wolbachia, and factors involved in the different cytoplasmic incompatibility phenotypes.     

Nucleic acid metabolism in cold-treated wheat embryos

The incorporation of ₃₂P into nucleic acid fractions separatedon a MAK column was compared for normally germinated and cold-treatedwheat embryos. ₃₂P accumulation in DNA fraction was decreasedby cold treatment, although that in the RNA fractions was slightlypromoted. The synthesis of the fraction, probably mRNA, elutedafter the peak of heavy rRNA was enhanced in cold-treated embryosand suppressed when the embryos were cold-treated in the presenceof 8-azaguanine, an inhibitor of vernalization. (Received May 2, 1975; )     

Impaired glucose tolerance without hypertriglyceridemia does not enhance postprandial lipemia.

Postprandial lipemia has been thought to be one of risk factors for coronary heart disease, and enhances in potential patients for atherosclerotic disease. Patients with impaired glucose tolerance (IGT) often show hypertriglyceride, which is caused by enhanced portprandial lipemia. Therefore, postprandial lipemia in patients with IGT and without hypertriglyceridemia has not been cleared. We have examined the levels of plasma triglyceride and chylomicron remnants after a high fat meal load (1250 kcal, 40% fat and 420 mg cholesterol) in 13 normotriglyceridemic subjects with IGT and 10 controls with normal glucose tolerance (NGT). Chylomicron remnants were evaluated as remnant-like particles (RLP) that were not bound to an immunoaffinity gel mixture containing apo A-I and apo B-100 monoclonal antibody. RLP cholesterol levels 4 hours after the fat load were significantly lower in IGT subjects than in NGT subjects. Increase of RLP cholesterol after the fat meal load only significantly correlated with increase of insulin during the first 30 min after a 75 g oral glucose tolerance test, but not fasting lipid, insulinogenic index and HOMA-R (homeostasis model) in all subjects. These results suggest that postprandial response does not enhance in IGT subjects, and may associate with early-phase insulin secretion and without insulin resistance in normotriglyceridemic men with IGT or NGT.     

Some Characteristics of Protein Kinases in Lemna paucicostata

The three protein kinases of Lemna paucicostata that are separableby DEAE-Sephacel chromatography have been designated PI, PIIand PIII [Kato et al. (1983) Plant & Cell Physiol. 24: 841].The optimum pH for the PI and PII enzymes was 7.5 and for thePHI enzyme 7.0. The activities of these enzymes were stimulatedby divalent cations, the maximum stimulation being producedby 5 nw Mg^{2 $} for PI, by 3 mM Co^{2 $} for PII and by 1 mM Mn^2$ for PIII. The cytokinins; benzyladenine, kinetin and zeatin,inhibited the activity of the PIII enzyme. The molecular weightsof the PI and PII enzymes did not change after incubation withcAMP even though their activities were regulated by this compound. (Received October 17, 1983; )     

Further characterization of the in vitro hydrolysis of [Leu]- and [Met]enkephalin in rat plasma: HPLC-ECD measurement of substrate and metabolite concentrations.

Hydrolysis of [Leu]- and [Met]enkephalin was determined in whole rat plasma in vitro by using HPLC-ECD to measure Tyr, Tyr-Gly and Tyr-Gly-Gly formation. Although [Leu]- and [Met]enkephalin did not differ in Tyr or Tyr-Gly accumulation, the amount of Tyr-Gly-Gly resulting from [Met]enkephalin hydrolysis was greater than that resulting from [Leu]enkephalin hydrolysis, and [Met]enkephalin's half-life in plasma was slightly shorter than that of [Leu]enkephalin. By comparing metabolite formation in the presence and absence of peptidase inhibitors with high selectivity for their respective enzymes, these studies demonstrated that aminopeptidase M and angiotensin converting enzyme are the major peptidases that hydrolyze enkephalins in rat plasma.     

RELATIONSHIPS AMONG MORPHOLOGICAL STATUS, STEROID HORMONES, AND POST-THAWING VIABILITY OF FROZEN SPERMATOZOA OF MALE MINKE WHALES (BALAENOPTERA ACUTOROSTRATA)

Spermatozoa from 21 mature minke whales ( Balaenoptera acutorostrata ) taken in the Antarctic Ocean for Japanese research were recovered from vasa deferentia, diluted 1:9 in a Tris-based diluent, and frozen at - 80°C on board the vessel. After a period ranging from 45 to 125 d, the samples were transferred to liquid nitrogen and transported to the laboratory. After thawing at 37°C the motility (percentage of motile spermatozoa), vitality (proportion of live spermatozoa), and sperm concentration were determined for each sample. These values were tested for correlations with morphological measurements (body size, body weight, testis weight) and serum concentrations of progesterone (Pd), estradiol-17β (E2), and testosterone (T). Ten of 21 samples had motile spermatozoa (2%-40%). Although no motile spermatozoa were observed in 1.1 samples, all sperm samples were examined by eosinnigrosin staining and showed vitality levels of 3%44%. It was found that the motility (Y = 0.54) and vitality (r = 0.53) of the spermatozoa were significantly (P < 0.01) correlated with the E₂ levels (8.50 ± 1.80 pg/ml). Serum T levels (0.07 ± 0.02 ngml) were significantly correlated with the E₂ levels (r = 0.58, P < 0.01>, but sperm concentrations were not correlated with either Ea or T levels. The present study demonstrates that spermatozoa of minke whales can be successfully cryopreserved.     

Direct observation of swimming behaviour in a shallow-water scavenging amphipod Scopelocheirus onagawae in relation to chemoreceptive foraging

Direct observations on foraging behaviour of scavenging lysianassid amphipods have been limited, and no previous study has examined the effect of food odour quantitatively on the behaviour. The present study recorded the swimming behaviour of the amphipod Scopelocheirus onagawae using videographic techniques before and after the introduction of food odour (amino acid solution). S. onagawae showed consistent nocturnal activity swimming at a high speed (16.8 cm s^− 1) with an approximately straight trajectory in various directions before and after the introduction of odour in which the amino acid concentration was below the behavioural threshold concentration for this species (1.0 × 10^− 7 mol l^− 1). High speed multidirectional linear swimming is thought to be advantageous for these amphipods, enabling them to survey across a broad area. After the first encounter with the odour plume above the behavioural threshold concentration, the amphipods slowed down their swimming speed (ca. 9.7 cm s^− 1) with a short time-lag (ca. 0.42 s), and thereafter they frequently turned so that they remained within the odour plume. Once moved out of the odour plume, the amphipods quickly returned to the plume with a shorter response time (ca. 0.1 s) than that in the first detection of the odour plume, suggesting that the sensory adaptation is involved with the tracking of the odour. Our study demonstrated that chemoreception is a major factor causing behavioural change in scavenging amphipods at the edge of the odour plume.