Maternal induction of larval diapause and its sensitive stage in the blow fly Lucilia sericata (Meigen) (Diptera: Calliphoridae)

Lucilia sericata has a facultative diapause in the third larval instar after cessation of feeding. Induction of the diapause is influenced by the photoperiod and temperature conditions experienced by insects in the parental generation as well as those experienced by the larvae themselves. The sensitive stage of the parental generation for induction of diapause was examined using diapause‐averting conditions of 16 h light : 8 h darkness (LD 16:8) at 25°C and diapause‐inducing conditions of LD 12:12 at 20°C. The incidence of diapause in the progeny was predominantly determined by the conditions experienced by the parents in the adult stage. Moreover, the results of reciprocal crosses showed that only the mother's experience is involved in the induction of diapause in the progeny.     

Effects of Forest Use on Aphyllophoraceous Fungal Community Structure in Sarawak, Malaysia

Aphyllophoraceous fungi are expected to reflect changes in the environmental conditions caused by forest use. To reveal the effects of forest uses on the fungal community structure, we performed a 3‐month survey of aphyllophoraceous species in five forest types (undisturbed primary forest, isolated patches of primary forest, old and young fallow forest, and rubber plantations) in Sarawak, Malaysia in 2005. We used a canonical correspondence analysis (CCA) to reveal the relationships between fungal community composition and the environmental variables (canopy openness, soil water potential, amount and composition of coarse woody debris, litter mass, basal area, plant species composition). A total of 155 samples from 67 species were collected during the study period. The fungal species density represented by the number of species in a transect differed significantly among forest types. The fungal species density increased significantly with increasing number of pieces of coarse woody debris (CWD), but decreased significantly with increasing the scores of second axis of principal component analysis (PCA) for plant species composition. In the CCA ordination, automatic forward selection revealed that only the number of pieces of CWD significantly affected the fungal species composition. The occurrences of Flabellophora licmophora, Coriolopsis retropicta, Microporus vernicipes, and Amauroderma subrugosum were positively correlated with the number of pieces of CWD. Our study clearly demonstrated that forest use negatively affected aphyllophoraceous fungal diversity and suggest that the quantity of CWD would be an important determinant of fungal diversity and composition.     

Application of high-performance liquid chromatography with a chemiluminescence detection system to determine catecholamines in urine

Chemiluminescence generated with the reaction of bis(2,4,6-trichlorophenyl)oxalate and hydrogen peroxide was applied to a detection system for high-performance liquid chromatography to determine fluorescamine-labeled catecholamines. The sensitivity of the chemiluminescence detection system with 25 fmol of detection limit was approximately 20 times higher than that of a conventional fluorescence detection system. Norepinephrine and dopamine in human urine were determined by the use of the new high-performance liquid chromatography detection system with the coefficient of variation of less than 4.0%. Good correlations (r = 0.998 for norepinephrine and r = 0.999 for dopamine) were obtained between the values by the present method and the conventional method.     

Does single-amino-acid replacement work in favor of or against improvement of the thermostability of immobilized enzyme?

Thermostabilities of kanamycin nucleotidyltransferase and of its mutants that became thermostable, in the free state, because of single-amino-acid replacements were studied after immobilization of the enzymes on cyanogen bromide-activated Sephadex G-200 particles. Lys in place of Gln at position 102 decreased the thermostability of the immobilized enzyme, whereas replacement with other amino acids enhanced it.     

Stromal fat content of the parathyroid gland

The proportion of stromal fat cells to parenchymal cells in 100 normal parathyroid glands was determined by the image analyzing computer technique. The parathyroid glands were resected at the time of thyroidectomy in 86 patients with thyroid tumors. None of the patients had any evidence of parathyroid dysfunction preoperatively. In the histologic sections of the parathyroid glands, the average percentage of stromal fat cell content was 38%. The percentage of stromal fat cells was correlated with the age and the body constitution of the patients, but the percentages of fat cells varied widely among glands in the given age and body constitution ranges. It was therefore not possible to discriminate a normal parathyroid gland from an abnormal gland solely on the basis of microscopic determination of stromal fat cell content.     

Modification of Male Courtship Motivation by Olfactory Habituation via the GABAA Receptor in Drosophila melanogaster

A male-specific component, 11-cis-vaccenyl acetate (cVA) works as an anti-aphrodisiac pheromone in Drosophila melanogaster. The presence of cVA on a male suppresses the courtship motivation of other males and contributes to suppression of male-male homosexual courtship, while the absence of cVA on a female stimulates the sexual motivation of nearby males and enhances the male-female interaction. However, little is known how a male distinguishes the presence or absence of cVA on a target fly from either self-produced cVA or secondhand cVA from other males in the vicinity. In this study, we demonstrate that male flies have keen sensitivity to cVA; therefore, the presence of another male in the area reduces courtship toward a female. This reduced level of sexual motivation, however, could be overcome by pretest odor exposure via olfactory habituation to cVA. Real-time imaging of cVA-responsive sensory neurons using the neural activity sensor revealed that prolonged exposure to cVA decreased the levels of cVA responses in the primary olfactory center. Pharmacological and genetic screening revealed that signal transduction via GABA_A receptors contributed to this olfactory habituation. We also found that the habituation experience increased the copulation success of wild-type males in a group. In contrast, transgenic males, in which GABA input in a small subset of local neurons was blocked by RNAi, failed to acquire the sexual advantage conferred by habituation. Thus, we illustrate a novel phenomenon in which olfactory habituation positively affects sexual capability in a competitive environment.     

The Inner Nuclear Membrane Protein Nemp1 Is a New Type of RanGTP-Binding Protein in Eukaryotes

The inner nuclear membrane (INM) protein Nemp1/TMEM194A has previously been suggested to be involved in eye development in Xenopus, and contains two evolutionarily conserved sequences in the transmembrane domains (TMs) and the C-terminal region, named region A and region B, respectively. To elucidate the molecular nature of Nemp1, we analyzed its interacting proteins through those conserved regions. First, we found that Nemp1 interacts with itself and lamin through the TMs and region A, respectively. Colocalization of Nemp1 and lamin at the INM suggests that the interaction with lamin participates in the INM localization of Nemp1. Secondly, through yeast two-hybrid screening using region B as bait, we identified the small GTPase Ran as a probable Nemp1-binding partner. GST pulldown and co-immunoprecipitation assays using region B and Ran mutants revealed that region B binds directly to the GTP-bound Ran through its effector domain. Immunostaining experiments using transfected COS-7 cells revealed that full-length Nemp1 recruits Ran near the nuclear envelope, suggesting a role for Nemp1 in the accumulation of RanGTP at the nuclear periphery. At the neurula-to-tailbud stages of Xenopus embryos, nemp1 expression overlapped with ran in several regions including the eye vesicles. Co-knockdown using antisense morpholino oligos for nemp1 and ran caused reduction of cell densities and severe eye defects more strongly than either single knockdown alone, suggesting their functional interaction. Finally we show that Arabidopsis thaliana Nemp1-orthologous proteins interact with A. thaliana Ran, suggesting their evolutionally conserved physical and functional interactions possibly in basic cellular functions including nuclear transportation. Taken together, we conclude that Nemp1 represents a new type of RanGTP-binding protein.     

Some experiments and analysis of a predator-prey model: Interaction between Colpidium campylum and Alcaligenes faecalis in continuous and mixed culture

Following previous work in which a mass and monoxenous culture of Vorticella microstoma had been successfully established (Water Res., 7 , 615 lpar;1973) another species of Ciliata, Colpidium campylum was subjected to continuous cultivation using Alcaligenes faecalis as the sole bacterial food and asparagine as the limiting substrate. This work was primarily undertaken to reveal the interaction and biological oscillation between these two types of organisms which simulate theecological behavior of activated sludge. The fact that the bacteria tended to flocculate and/ or deflocculate depending on the protozoan populastion density was incorporated into the rate equations to account for the oscillation in individual population density of the predator-prey system The mathematical approach presented earlier by canal and other workers forbiological oscillation used a homogeneously of the bacterial food wasoverelooked in the earlier publication.