Role of insect sex pheromones in mating behavior. V. Profile of process on male flying approach toward sex pheromone source

Application of the kinetic theory of gas molecules to male zigzagging orientation, which is assumed as repeated encounter between sex pheromone puff and a flying male moth, derived a linear relationship between the number of turnings and the distance from the source where male began repeated turnings. Similar results are also obtained by computer simulation. This relationship was already obtained inHyphantria cunea males in the field within 2.0 meters downwind from the source. Theoretical simulation and observation results led us to conclude that male repeated turnings are restricted by the time during which males are able to take the approaching behavior to the source.     

Change in the community structure of ammonia-oxidizing bacteria in activated sludge during selective incubation for MPN determination

We investigated the changes in the community structure of ammonia-oxidizing bacteria (AOB) in activated sludge during incubation of the sludge in a medium selective for AOB. The number of AOB present in the activated sludge sample was enumerated by the most-probable-number (MPN) method. Both the activated sludge sample and the incubated samples for MPN determination were analyzed by polymerase chain reaction and denaturing gradient gel electrophoresis (PCR-DGGE). Universal PCR-DGGE indicated that even after 40-d incubation in a medium selected for AOB, the MPN samples were predominantly composed of heterotrophic bacteria and not AOB. Denitrification by heterotrophic bacteria might lead to the underestimation of the MPN count of AOB. Not dominated in whole bacteria, one species of AOB was detected in both original activated sludge and samples after MPN incubation by PCR-DGGE targeting AOB. Furthermore, two new species of AOB were detected only after incubation. Therefore, the community structure of AOB in the MPN samples partially resembled that in the original activated sludge.     

Gigantism associated with McCune-Albright's syndrome

The case of a 16 year-old boy with McCune-Albright's syndrome which is rarely accompanied by gigantism was studied endocrinologically. The stimulation of growth hormone (GH) release by hypoglycemia, the decline of elevated GH by hyperglycemia and a little lower somatostatin like immunoreactivity (SLI) may support abnormalities of hypothalamic function, but the existence of pituitary microadenoma cannot be ruled out because of the paradoxical suppression of GH release by oral administration of bromocriptine (CB-154) and L-DOPA and the stimulation of GH release by intravenous administration of TRH.     

Dopamine inhibits thyrotropin-releasing hormone release from rat adrenal gland in vitro

The effects of dopamine on the release of thyrotropin-releasing hormone (TRH) from the rat adrenal gland were studied in vitro. The rat adrenal glands were incubated in medium 199 with 1.0 mg/ml of bacitracin and 100 micrograms/ml of ascorbic acid (pH 7.4) (medium) for 20 min. The amount of TRH release into the medium was measured by radioimmunoassay. The immunoreactive TRH (ir-TRH) release from the rat adrenal gland was inhibited significantly in a dose-related manner with the addition of dopamine and enhanced with the addition of pimozide or domperidone to the medium. Dopamine's effects on ir-TRH release from the adrenal gland were blocked with the addition of pimozide or domperidone. The elution profile of methanol-extracted rat adrenal gland was identical to that of synthetic TRH. The findings suggest that the dopaminergic system inhibits TRH release from the rat adrenal gland.     

The effect of L-DOPA administration on thyrotropin (TSH) and thyrotropin releasing hormone (TRH) levels in serum in primary or pituitary hypothyroidism.

The effect of acute administration of L-DOPA on TSH and TRH levels in serum was studied in primary or pituitary hypothyroidism. TRH levels in serum fell and then returned to initial levels after L-DOPA administration in primary or pituitary hypothyroidism. TSH levels in serum fell and then returned to initial levels after L-DOPA administration in primary hypothyroidism. T4 and T3 levels in serum did not change after L-DOPA administration in primary or pituitary hypothyroidism. These data suggested that L-DOPA might act directly to hypothalamus.     

Effects of acetylcholine on thyrotropin-releasing hormone release from the rat caecum in vitro

Effects of acetylcholine on the release of thyrotropin-releasing hormone (TRH) from the rat caecum in vitro were studied. The rat caecum was incubated in medium 199 with 1.0 mg/ml of bacitracin and 100 micrograms/ml of ascorbic acid (pH 7.4) (medium). The amount of TRH release into the medium was measured by radioimmunoassay. The immunoreactive TRH (ir-TRH) release from the rat caecum was enhanced significantly in a dose-related manner with the addition of acetylcholine, but not changed with atropine. The stimulatory effect of acetylcholine on ir-TRH release from the rat caecum was blocked with an addition of atropine. Elution profile of acid-methanol-extracted rat caecum on Sephadex G-10 was identical to that of synthetic TRH. The findings suggest that the cholinergic system stimulates TRH release from the rat caecum in vitro.     

Evidence for Generation of Suppressor T Cells in Mycobacterium lepraemurium-Infected CBA/J Mice,a Mouse Strain Highly Susceptible to the Infection

Susceptibility to Mycobacterium lepraemurium (MLM) infection markedly differed between two mouse strains, CBA/J and C57BL/6. CBA/J mice showed high susceptibility to MLM infection and developed either very weak or no delayed-type hypersensitivity (DTH) to MLM antigen after the injection of MLM. In contrast, C57BL/6 mice, which were resistant to MLM infection, showed significant DTH reaction to MLM antigen after the injection. Treatment of CBA/J mice with cyclophosphamide (Cy) conferred significant resistance to MLM infection on the CBA/J mice, and the treated mice developed a strong anti-MLM DTH response after the MLM injection. When spleen cells from MLM-infected CBA/J mice were transferred to Cy-treated and MLM-infected syngeneic mice, the anti-MLM DTH reaction of the recipient mice was suppressed. Treatment of the spleen cells to be transferred with anti-Thy-1.2 antibody or anti-I-J^k antiserum plus complement abrogated the suppressive activity. Thus, it is suggested that the high susceptibility of CBA/J mice to MLM infection is due to the generation of Cy-sensitive, I-J^k-positive suppressor T cells after infection with MLM.     

Effects of opioid peptides on thyrotropin-releasing hormone release from the rat caecum in vitro

Effects of opioid peptides (beta-endorphin, dynorphin (1-13). alpha-neoendorphin, beta-neoendorphin, leucine-enkephalin, methionine-enkephalin) on the release of thyrotropin-releasing hormone (TRH) from the rat caecum were studied in vitro. The rat caecum was incubated in medium 199 with 1.0 mg/ml of bacitracin (pH 7.4) (medium). The amount of TRH release from the rat caecum into the medium was measured by radioimmunoassay. The immunoreactive TRH (ir-TRH) release from the rat caecum was inhibited significantly in a dose-related manner with the addition of opioid peptides. The inhibitory effects of opioid peptides on ir-TRH release from the rat caecum were blocked with an addition of naloxone. The elution profile of acid-methanol-extracts of rat caecum on Sephadex G-10 was identical to that of synthetic TRH. The findings suggest that opioid peptides inhibit TRH release from the rat caecum in vitro.