Effect of hypophysectomy and growth hormone administration on somatostatin and gastrin content in the stomach of rats

The effect of hypophysectomy and bovine growth hormone (GH) administration on somatostatin (SRIF) content as well as gastrin content in the rat stomach was investigated. SRIF content was determined by a specific radioimmunoassay. The total SRIF content in the stomach had decreased 4 weeks after hypophysectomy but was restored significantly in those rats which were subjected to bovine GH administration for 7 days after hypophysectomy. Furthermore, in control rats, an increase in SRIF content in the stomach was observed after 7 days of GH administration. Similar changes in total content of gastrin were observed after hypophysectomy and bovine GH administration, although these changes were not significant. These results indicate that GH may influence gastric function through changes in SRIF and gastrin content in the stomach.     

Changes in expression of inhibin subunits in the cyclic golden hamster (Mesocricetus auratus) and the regulation of inhibin alpha subunit production by luteinizing hormone

In the present study, changes in localization of each inhibin subunit in the ovary were investigated during the estrous cycle of the golden hamster. The effect of LH surge on changes in localization in inhibin alpha subunit in the ovary was also investigated. Inhibin alpha subunit was localized in granulosa cells of various stages of follicles throughout the estrous cycle. Inhibin alpha subunit was also present in numerous interstitial cells on days 1 and 2 (day 1 = day of ovulation), but the number of positive interstitial cells was fewer on days 3 and almost disappeared on day 4 of the estrous cycle. Newly formed luteal cells were also positive for inhibin alpha subunit on days 1 and 2. On the other hand, positive reactions for inhibin beta A and beta B subunits were only present in the granulosa cells of healthy antral follicles. However, a positive reaction for inhibin beta B subunit in peripheral mural granulosa cells disappeared on days 3 and 4 of the estrous cycle. Treatment with LHRH-AS at 1100 h on day 4 completely blocked the luteinizing hormone (LH) surge and ovulation, although relatively high concentrations of plasma follicle-stimulating hormone (FSH) were maintained throughout the experiment. There were few positive reactions for inhibin alpha subunit in theca and interstitial cells 24 hr after LHRH-AS injection. The effect of LHRH-AS treatment was blocked by a single injection of 10 IU human chorionic gonadotropin. These results suggest that the major source of dimeric inhibin in the cyclic hamster was granulosa cells of healthy antral follicles. Different distribution pattern of inhibin beta A from beta B subunits in large antral follicles on days 3 and 4 of the estrous cycle suggests different secretion patterns of inhibin A from B on these days. Furthermore, the LH surge may be an important factor to induce production of inhibin alpha subunit in interstitial cells of the cyclic hamster.     

Evaluation of the importance of lactate for the activation of ethanolic fermentation in lettuce roots in anoxia

According to the Davies–Roberts hypothesis, plants primarily respond to oxygen limitation by a burst of lactate production and the resulting pH drop in the cytoplasm activates ethanolic fermentation. To evaluate this system in lettuce ( Lactuca sativa L.), seedlings were subjected to anoxia and in vitro activities of alcohol dehydrogenase (ADH, EC 1.1.1.1), pyruvate decarboxylase (PDC, EC 4.1.1.1) and lactate dehydrogenase (LDH, EC 1.1.1.27) and concentrations of ethanol, acetaldehyde and lactate were determined in roots of the seedlings. The in vitro activities of ADH and PDC in the roots increase in anoxia, whereas no significant increase was measured in LDH activity. At 6 h, the ADH and PDC activities in the roots kept in anoxia were 2.8- and 2.9-fold greater than those in air, respectively. Ethanol and acetaldehyde in the roots accumulated rapidly in anoxia and increased 8- and 4-fold compared with those in air by 6 h, respectively. However, lactate concentration did not increase and an initial burst of lactate production was not found. Thus, ethanol and acetaldehyde production occurred without an increase in lactate synthesis. Treatments with antimycin A and salicylhydroxamic acid, which are respiratory inhibitors, to the lettuce seedlings in the presence of oxygen increased the concentrations of ethanol and acetaldehyde but not of lactate. These results suggest that ethanolic fermentation may be activated without preceding activation of lactate fermentation and may be not regulated by oxygen concentration directly.     

Deterred oviposition response of Monochamus alternatus (Coleoptera: Cerambycidae) to oviposition scars occupied by eggs

1 The oviposition behaviour and response of Monochamus alternatus females to oviposition scars were investigated in the laboratory. 2 Prior to oviposition, females gnawed at the bark surface of Pinus densiflora bolts to make a wound. Then females turned their bodies 180° to position their ovipositors over the wounds and inserted them under the bark through the wounds. After an oviposition, a jelly was deposited while the ovipositor was still inserted. The females then withdrew their ovipositors and rubbed the oviposition scars with the tips of their abdomens. 3 When searching females encountered oviposition scars, they stopped walking and drummed the surface and inside of the oviposition scars with their maxillary and labial palpi. 4 Eighty-six percent of females left oviposition scars containing single eggs after the palpation. By contrast, when females encountered oviposition scars containing no eggs, 76% of them began to gnaw at the scars and 64% deposited single eggs. The response to artificial oviposition scars was similar to that to vacant oviposition scars made by the females. 5 The results of various observations and experiments showed that the females could recognize oviposition scars and discriminate the scars occupied by single eggs from vacant ones, and suggested that the palpation of oviposition scars was the critical discrimination behaviour, indicating mediation by chemical cues.     

Guild structures of seed insects in relation to acorn development in two oak species

We investigated patterns of acorn growth in Quercus variabilis Blume and Quercus serrata Thunb., seasonal trends in emergence of seed insects found in the acorns, oviposition periods of the insects and falling periods of insect-infested acorns. In Q. variabilis, two insect guilds were associated with acorn development: (i) the immature acorn feeding (IAF) guild [Curculionidae sp., Poecilips cardamomi (Schaufuss), and Characoma ruficirra (Hampson)]; and (ii) the mature acorn feeding (MAF) guild [Curculio robustus (Roelofs), Curculio sikkimensis (Heller), and Cydia glandicolana (Danilevsky)]. In Q. serrata, there were three guilds: (i) the pistillate flower feeding (PFF) guild (cynipid wasp); (ii) the IAF guild [sap absorption by Mechoris ursulus (Roelofs)]; and (iii) the MAF guild (M. ursulus, C. sikkimensis, Cydia danilevskyi (Kuznetzov), C. glandicolana and Autostichidae sp.). The succession of guilds during acorn development may be a consequence of the use by different species of the limited food resource. The lack of a PFF guild in Q. variabilis that was found in our field site would have a positive effect on IAF guilds in utilizing the acorns.     

In Situ Activity and Spatial Organization of Anaerobic Ammonium-Oxidizing (Anammox) Bacteria in Biofilms

We investigated autotrophic anaerobic ammonium-oxidizing (anammox) biofilms for their spatial organization, community composition, and in situ activities by using molecular biological techniques combined with microelectrodes. Results of phylogenetic analysis and fluorescence in situ hybridization (FISH) revealed that “Brocadia”-like anammox bacteria that hybridized with the Amx820 probe dominated, with 60 to 92% of total bacteria in the upper part (<1,000 μm) of the biofilm, where high anammox activity was mainly detected with microelectrodes. The relative abundance of anammox bacteria decreased along the flow direction of the reactor. FISH results also indicated that Nitrosomonas-, Nitrosospira-, and Nitrosococcus-like aerobic ammonia-oxidizing bacteria (AOB) and Nitrospira-like nitrite-oxidizing bacteria (NOB) coexisted with anammox bacteria and accounted for 13 to 21% of total bacteria in the biofilms. Microelectrode measurements at three points along the anammox reactor revealed that the NH₄⁺ and NO₂⁻ consumption rates decreased from 0.68 and 0.64 μmol cm⁻² h⁻¹ at P2 (the second port, 170 mm from the inlet port) to 0.30 and 0.35 μmol cm⁻² h⁻¹ at P3 (the third port, 205 mm from the inlet port), respectively. No anammox activity was detected at P4 (the fourth port, 240 mm from the inlet port), even though sufficient amounts of NH₄⁺ and NO₂⁻ and a high abundance of anammox bacteria were still present. This result could be explained by the inhibitory effect of organic compounds derived from biomass decay and/or produced by anammox and coexisting bacteria in the upper parts of the biofilm and in the upstream part of the reactor. The anammox activities in the biofilm determined by microelectrodes reflected the overall reactor performance. The several groups of aerobic AOB lineages, Nitrospira-like NOB, and Betaproteobacteria coexisting in the anammox biofilm might consume a trace amount of O₂ or organic compounds, which consequently established suitable microenvironments for anammox bacteria.     

Deficiency of Dol-P-Man Synthase Subunit DPM3 Bridges the Congenital Disorders of Glycosylation with the Dystroglycanopathies

Alpha-dystroglycanopathies such as Walker Warburg syndrome represent an important subgroup of the muscular dystrophies that have been related to defective O-mannosylation of alpha-dystroglycan. In many patients, the underlying genetic etiology remains unsolved. Isolated muscular dystrophy has not been described in the congenital disorders of glycosylation (CDG) caused by N-linked protein glycosylation defects. Here, we present a genetic N-glycosylation disorder with muscular dystrophy in the group of CDG type I. Extensive biochemical investigations revealed a strongly reduced dolichol-phosphate-mannose (Dol-P-Man) synthase activity. Sequencing of the three DPM subunits and complementation of DPM3-deficient CHO2.38 cells showed a pathogenic p.L85S missense mutation in the strongly conserved coiled-coil domain of DPM3 that tethers catalytic DPM1 to the ER membrane. Cotransfection experiments in CHO cells showed a reduced binding capacity of DPM3(L85S) for DPM1. Investigation of the four Dol-P-Man-dependent glycosylation pathways in the ER revealed strongly reduced O-mannosylation of alpha-dystroglycan in a muscle biopsy, thereby explaining the clinical phenotype of muscular dystrophy. This mild Dol-P-Man biosynthesis defect due to DPM3 mutations is a cause for alpha-dystroglycanopathy, thereby bridging the congenital disorders of glycosylation with the dystroglycanopathies.     

High Predation Pressure by an Introduced Flatworm on Land Snails on the Oceanic Ogasawara Islands1

The introduction of a predatory flatworm, Platydemus manokwari, has been considered a cause of the decline of endemic land snails on the tropical oceanic islands. To clarify the effect of P. manokwari on land snail survival in the field, we examined survival rates of snails experimentally placed in areas where snails are absent (i.e., P. manokwari is present) on Chichijima, Ogasawara (Bonin) Islands. We found that over 50 and 90 percent of the snails were dead after 3 and 11 d, respectively, and that the main cause of mortality was predation by P. manokwari.     

Altered localization of amyloid precursor protein under endoplasmic reticulum stress

Recent reports have shown that the endoplasmic reticulum (ER) stress is relevant to the pathogenesis of Alzheimer disease. Following the amyloid cascade hypothesis, we therefore attempted to investigate the effects of ER stress on amyloid-beta peptide (Abeta) generation. In this study, we found that ER stress altered the localization of amyloid precursor protein (APP) from late compartments to early compartments of the secretory pathway, and decreased the level of Abeta 40 and Abeta 42 release by beta- and gamma-cutting. Transient transfection with BiP/GRP78 also caused a shift of APP and a reduction in Abeta secretion. It was revealed that the ER stress response facilitated binding of BiP/GRP78 to APP, thereby causing it to be retained in the early compartments apart from a location suitable for the cleavages of Abeta. These findings suggest that induction of BiP/GRP78 during ER stress may be one of the regulatory mechanisms of Abeta generation.