Parental investment and offspring sex ratio in a solitary bee,Anthidium septemspinosum lepeletier (Hymenoptera: Megachilidae)

Anthidium septemspinosum is a solitary, tube-nesting bee. Studies onA. septemspinosum were made to investigate how offspring sex ratios were influenced by maternal conditions. Males were generally larger than females, indicating that parental investment between sexes differed. Body size was related to male mating success, but was not related to nesting success of females. Large and young mother bees, who had more ability to invest, invested more in male offspring while small and old mothers invested more in female offspring. These results indicate that mother bees of this species are able to adaptively manipulate offspring sex ratio in relation to their ability to invest in offspring, as predicted in mammals by Trivers & Willard (1973).     

Postnatal reorganization of actin filaments and differentiation of intercellular boundaries in the rat aortic endothelial cells

Postnatal change in the distribution of actin filaments in endothelial cells was studied in the rat aorta by use of rhodamine-phalloidin staining and confocal laser scanning microscopy. Endothelial cells of the rat aorta possessed two populations of actin filament bundles, namely, peripheral bands at the cell border and stress fibers running longitudinally in the cytoplasm. Aortic endothelial cells of the neonatal rat contained only stress fibers, whereas those of the 10-day-old rat developed both peripheral bands and stress fibers. After 20 days of age, aortic endothelial cells had predominantly peripheral bands with occasional stress fibers around the branch orifices. During postnatal development the length density of stress fibers in aortic endothelial cells decreased, whereas individual stress fibers in endothelial cells were shortened. Electron-microscopic observation revealed that the high intercellular boundaries of aortic endothelial cells at birth decreased in height and developed cytoplasmic interdigitations after 20 days of age. The occurrence of peripheral bands at the cell border is thought to be closely related to formation of cytoplasmic interdigitation which strengthens the mechanical connection between endothelial cells against increasing transmural pressure. Expression of stress fibers in aortic endothelial cells of the neonatal rat is supposed to be affected by longitudinal elongation of the developing aorta, whereas their postnatal decrease is though to be correlated with the change of fluid shear stress loaded in the aortic endothelium.     

Expression in Yeast of a Fusion Gene Composed of the Promoter of a Heat-Shock Gene from Arabidopsis and a Bacterial Gene for {beta}-Glucuronidase

Production of a functional ß-glucuronidase (GUS) proteinwas induced by exposure of exponentially growing yeast cellsto heat shock after transformation of the GUS gene under thecontrol of the promoter of the heat-shock gene, HSP18.2, fromArabidopsis. Yeast cyr and bcy mutations appeared to have essentiallyno effect. ¹Present Address: Laboratory of Plant Molecular Biology, TheRockefeller University, 1230 York Avenue, New York, NY 10021-6399,U.S.A.     

Retrotransposon-induced ectopic expression of the Om(2D) gene causes the eye-specific Om(M) phenotype in Drosophila ananassae

Optic morphology (Om) mutations in Drosophila ananassae map to at least 22 loci, which are scattered throughout the genome. Om mutations are all semidominant, neomorphic, nonpleiotropic, and associated with the insertion of a retrotransposon, tom. We have found that the Om(2D) gene encodes a novel protein containing histidine/proline repeats, and is ubiquitously expressed during embryogenesis. The Om(2D) RNA is not detected in wild-type eye imaginal discs, but is abundantly found in the center of the eye discs of Om(2D) mutants, where excessive cell death occurs. D. melanogaster flies transformed with the Om(2D) cDNA under control of the hsp70 promoter display abnormal eye morphology when heat-shocked at the third larval instar stage. These results suggest that the Om(2D) gene is not normally expressed in the eye imaginal discs, but its ectopic expression, induced by the tom element, in the eye disc of third instar larvae results in defects in adult eye morphology.     

Correction to: Comparison of the usability of an automatic sleep staging program via portable 1-channel electroencephalograph and manual sleep staging with traditional polysomnography

Sleep and Biological Rhythms -     

The role of polypyrrole as charge transfer mediator and immobilization matrix for d-fructose dehydrogenase in a fructose sensor

A fructose dehydrogenase (FDH) modified electrode is produced by the electroadsorption of a layer of FDH on a platinum electrode followed by the electropolymerization of a polypyrrole (PPy) film around and over the enzyme. This immobilizes and stabilizes the enzyme as well as providing an electron transfer pathway to the electrode. The amperometric response to fructose and the enzymatic activity are measured as a function of PPy film thickness. The electrode is shown to have a maximum response at a PPy thickness of approximately the thickness of the enzyme layer. A measure of the electrode efficiency is also obtained, this is the amperometric response to fructose as a percentage of that expected on the basis of the enzyme activity. The functioning of the electrode is also dependent on the counter-ion used for PPy polymerization. This is shown to be mainly related to the nucleation and growth of the PPy film in the interfacial region.     

Elucidation of the mechanism enhancing the avidity of lectin with oligosaccharides on the solid phase surface

The mechanism underlying molecular recognition of lectins waselucidated by a novel solid phase binding assay system basedon surface plasmon resonance. When the apparent affinities ofinteractions between chitooligosaccharides and wheat germ agglutininwere compared between lectin-immobilized and oligosaccharide-immobilizedassay systems, the affinity constants (Ka) calculated for theformer system were in good agreement with the previously reportedvalues measured in solution. On the other hand, in the lattersystem, the calculated Ka could be more than 10,000 times higherthan the values in solution at lower lee tin concentrations.To elucidate the reason for this, we systematically investigatedthe effects of the oligosaccha-ride immobilized density andthe lectin valence on the apparent affinity in the oligosaccharide-immobilizedassay system. Both the apparent association (k_ass) and dissociationrate constants (k_diss) showed a tendency to decrease as theoligosaccharide density increased. This effect was most remarkablefor the interaction possessing an extremely fast intrinsic K_ass.Oligomerization of lectin enhanced the avidity due to a significantreduction in k_diss. These phenomena could be explained by consideringthe nonhomogeneous conditions under which binding occurred.The reaction in a nonhomogeneous state is limited by the masstransport effect, and the effect of rebinding becomes so largethat it cannot be disregarded. These findings are the firstto demonstrate the importance of the mass transport effect inmodulating the affinity of lectin for oligosaccharides on asolid phase surface. avidity clustering effect lectin mass transport surface plasmon resonance     

Mucopolysaccharidosis IVA: structural gene alterations identified by Southern blot analysis and identification of racial differences

Ninety-six alleles (36 alleles of Japanese and 60 of Caucasian origin) from forty-eight patients with mucopolysaccharidosis IVA were investigated for structural gene alterations using Southern blot analysis. All patients had a previously demonstrated deficiency of N-acetylgalactosamine-6-sulfate-sulfatase and exhibited a wide spectrum of clinical severity. Initially, using the fulllength cDNA as a probe, five of 36 chromosomes from the Japanese patients revealed similar rearrangements with respect to DNA digested with BamHI, SacI, and XhoI. Subsequent analysis using seven genomic fragments, covering the entire gene, enhanced the detection of aberrant fragments produced by the above restriction enzymes. Conversely, the 60 chromosomes of Caucasian origin revealed no evidence of large structural rearrangements when analyzed by these methods. There was a statistically significant difference between the two populations (P < 0.01). A severely affected Japanese patient showed structural rearrangements on both chromosomes by means of BamHI blots. An 8.0-kb fragment and a highly polymorphic 7.0-kb to 11.0-kb fragment present in normal individuals disappeared and two aberrant fragments of 11.5 kb and 12.0 kb were observed. Three other Japanese patients also showed these two aberrant fragments, in addition to the normal fragment pattern, and were thus heterozygous for this rearrangement. Interpretation of Southern blots was difficult because of the complexity of polymorphic bands resulting from variable number of tandem repeat elements. However, by utilizing these aberrant fragments or polymorphic bands, carrier detection was effective, even in families with poorly characterized mutations. Hybridization with probe MG-A (5end genomic probe in intron 1) showed a 8.4-kb fragment in BamHI blots of one Japanese and one Caucasian patient; XhoI, SacI, and EcoRI blots were normal. Since this BamHI alteration was also observed in one normal control, it appears to be a rare nonpathological polymorphism.     

The pollination ecology ofBletilla striata (Orchidaceae)

Anthecological observations of an orchidBletilla striata were carried out in Kobe, Japan. The purplish pink flowers were visited by 26 species of insects belonging to Hymenoptera, Diptera and Lepidoptera, although the flower did not offer food rewards of any kind. Candidates for pollination were seven species of aculeate Hymenoptera with a body size that well fitted the space in between the column and labellum. The most effective candidate was the male of the longhorn beeTetralonia nipponensis, judging from its abundance and legitimate intrafloral behavior. The female ofT. nipponensis and the other six species also contributed to promote out-crossing, but to a lesser extent than the maleT. nipponensis, since they occasionally exhibited illegitimate intrafloral behaviors for pollination and also, their flower visitation rate was lower.