Production-dependent reproductive allocation of a tall tree speciesQuercus serrata

The reproductive allocation (allocation of net production to acorns) of a tall tree speciesQuercus serrata was estimated by a method combining branch diameter distribution and the sampling of acorns per branch. Acorn production per branch of 0.5-cm diameter significantly varied among individuals and years, but not significantly across tree size. Leaf production per branch of 0.5-cm diameter had little annual fluctuation, while that of acorns fluctuated about 6 times between the maximum and minimum. The reproductive allocation was regressed against vegetative allocation, following the general model of klinkhameret al. (1992); the reproduction had a beginning threshold and reproductive allocation increased drastically at relatively young stage after the tree began reproduction. With its small threshold production, coppicing traits and large maximum size,Q. serrata seemed adaptive to infrequent but large-scale disturbances like fires.     

4-Acylamino-6-arylfuro[2,3-d]pyrimidines: potent and selective glycogen synthase kinase-3 inhibitors

Modeling studies of a furo[2,3-d]pyrimidine GSK-3 hit compound 1 superimposed onto the X-ray crystal structure of a legacy pyrazolo[3,4-c]pyridazine GSK-3 inhibitor 2 led to the identification of 4-acylamino-6-arylfuro[2,3-d]pyrimidine template 3. Synthesis of analogues based on template 3 has resulted in a number of potent and selective GSK-3beta inhibitors. The most potent and selective compound was the m-pyridyl analogue 24.     

Isolation of B subunit‐specific monoclonal antibody clones that strongly neutralize the toxicity of Shiga toxin 2

Shiga toxin 2 (Stx2)‐specific mAb‐producing hybridoma clones were generated from mice. Because mice tend to produce small amounts of B subunit (Stx2B)‐specific antibodies at the polyclonal antibody level after immunization via the parenteral route, mice were immunized intranasally with Stx2 toxoids with a mutant heat‐labile enterotoxin as a mucosal adjuvant; 11 different hybridoma clones were obtained in two trials. Six of them were A subunit (Stx2A)‐specific whereas five were Stx2B‐specific antibody‐producing clones. The in vitro neutralization activity of Stx2B‐specific mAbs against Stx2 was greater than that of Stx2A‐specific mAbs on HeLa229 cells. Furthermore, even at low concentrations two of the Stx2B‐specific mAbs (45 and 75D9) completely inhibited receptor binding and showed in vivo neutralization activity against a fivefold median lethal dose of Stx2 in mice. In western blot analysis, these Stx2B‐specific neutralization antibodies did not react to three different mutant forms of Stx2, each amino acid residue of which was associated with receptor binding. Additionally, the nucleotide sequences of the V_H and V_L regions of clones 45 and 75D9 were determined. Our Stx2B‐specific mAbs may be new candidates for the development of mouse‐human chimeric Stx2‐neutralizing antibodies which have fewer adverse effects than animal antibodies for enterohemorrhagic Escherichia coli infection.     

Hepatoprotective effects of purple potato extract against D-galactosamine-induced liver injury in rats

We investigated the hepatoprotective effect of purple potato extract (PPE) against D-galactosamine (GalN)-induced liver injury in rats. PPE (400 mg) was administered once daily for 8 d, and then GalN (250 mg/kg of body weight) was injected at 22 h before the rats were killed. Serum tumor necrosis factor alpha (TNF-alpha), lactate dehydrogenase (LDH), alanine aminotransferase (ALT), and asparate aminotranferase (AST) levels increased significantly after injection of GalN, but PPE inhibited GalN-induced alterations in serum TNF-alpha, LDH, ALT, and AST levels. Hepatic lipid peroxide and glutathione levels in the control + GalN group were higher and lower respectively than those in the control group, and those in the PPE + GalN group did not differ from that in the control group. The lipid peroxide level in hepatic microsomes treated with 2,2'-azobis (2-amidinopropane) dihydrochloride in the PPE group was significantly lower than that in the control group. This suggests that PPE has hepatoprotective effects against GalN-induced hepatotoxicity via inhibition lipid peroxidation and/or inflammation in rats.     

Effect of gravity on apical dominance in Pharbitis nil.

When the upper part of main shoot of morning glory (Pharbitis nil) is gently bent down, lateral bud on the bending region is released from apical dominance and starts to elongate. But, clinorotating the bending shoots prevents the release of the lateral bud from apical dominance. These results suggest that gravity affects apical dominance in morning glory. Here we verified the gravity-regulated apical dominance by using a weeping morning glory defective in gravitropic response due to abnormal differentiation of endodermis. That is, bending main shoot of the weeping morning glory hardly caused the lateral bud to elongate. In addition, decapitation of apical bud released the lateral bud from apical dominance, and exogenous auxin applied to the cut surface of the decapitated stem was inhibitory to the outgrowth of the lateral bud in the wild type. However, the effect of auxin was much less in the weeping morning glory. Thus, apical dominance of the weeping morning glory was weaker and less influenced by gravity than that of the wild type, which could occur due to abnormal differentiation of endodermis required for graviperception.     

Intra-sexual Dimorphism in Male Mandibles and Male Aggressive Behavior in the Broad-Horned Flour Beetle Gnatocerus cornutus (Coleoptera: Tenebrionidae)

In the stored-product beetle, the broad-horned flour beetle, Gnatocerus cornutus (Fabricius), all males possess enlarged mandibles, widened gena, and a pair of small horns on the vertex, but females lack these completely. Observations of male-male interactions of G. cornutus showed that larger individuals won male-male fights, and that the mandibles were used as weapons. Morphological analysis based on the non-linearity test of Eberhard and Gutierrez's model (1991) showed that intra-sexual dimorphism in males was only found in the mandibles used in male-male combat, but not in the gena and horns. This beetle can be an ideal model for evolutionary studies of exaggerated weapons for male combat, because rearing successive generations and observing male fighting are easy.     

Stabilization of quaternary structure and activity of bovine liver catalase through encapsulation in liposomes

Bovine liver catalase was encapsulated in an aqueous phase of the phospholipid vesicle (liposome) to improve the stability of its tetrameric structure and activity. The catalase-containing liposomes (CALs) prepared were 30, 50 and 100 nm in mean diameters (CAL₃₀, CAL₅₀ and CAL₁₀₀, respectively). The CAL₁₀₀ included the types I, II and III based on the amounts of catalase encapsulated. The CAL₃₀, CAL₅₀ and CAL₁₀₀-I contained one catalase molecule per liposome, and the CAL₁₀₀-II and CAL₁₀₀-III on average 5.2 and 17 molecules, respectively. The storage stability of catalase in either CAL system was significantly increased compared to that of free catalase at 4 °C in a buffer of pH 7.4. At 55 °C, free catalase was much more deactivated especially with decreasing its concentration predominantly due to enhanced dissociation of catalase into subunits while it was so done at excessively high enzyme concentration mainly due to enhanced formation of catalase intermolecular aggregates. Among the three types of CAL₁₀₀, the CAL₁₀₀-II showed the highest thermal stability, indicating that an excess amount of catalase in the CAL₁₀₀-III was also disadvantageous to maintain an active form of the catalase even in liposome. In the CAL₁₀₀-III, however, the stability of catalase was significantly improved compared to that of free catalase at the same concentration. The CAL thermal stability was little affected by the liposome size as observed in the CAL₃₀, CAL₅₀ and CAL₁₀₀-I. An intrinsic tryptophan fluorescence of the catalase recovered from the CAL₁₀₀-II thermally treated at 55 °C revealed that a partially denatured catalase molecule was stabilized through its hydrophobic interaction with liposome membrane. This interaction depressed not only dissociation of catalase into subunits but also formation of an inactive intermolecular aggregate between the catalase molecules in a liposome. Furthermore, either type of CAL₁₀₀ showed a higher stability than free catalase in the successive decompositions of 10 mM H₂O₂ at 25 °C mainly because the H₂O₂ concentration was kept low inside liposomes due to the permeation barrier of the lipid membrane to H₂O₂.     

Alteration of the N-glycome of bovine milk glycoproteins during early lactation

Milk provides nutritional, immunological and developmental components for newborns. Whereas identification of such components has been performed by targeting proteins and free oligosaccharides, structural and functional analyses of the N-glycome of milk glycoproteins are scarce. In this study, we investigated, for the first time, the alterations of the bovine milk N-glycome during early lactation (1 day, 1, 2, 3 and 4 weeks postpartum), characterizing more than 80 N-glycans. The glycomic profile of colostrum on day 1 after calving differed substantially from that in other periods during early lactation. The proteins in colostrum obtained 1 day postpartum were more highly sialylated than milk samples obtained at other time points, and the N-glycolylneuraminic acid (Neu5Gc)/N-acetylneuraminic acid (Neu5Ac) ratio was significantly higher on day 1, showing a gradual decline with time. In order to dissect the N-glycome of colostrum, alterations of the N-glycosylation profile of major bovine milk proteins during the early lactation stage were elucidated, revealing that the alteration is largely attributable to qualitative and quantitative N-glycosylation changes of IgG, the major glycoprotein in colostrum. Furthermore, by preparing and analyzing IgGs in which the N-glycan structure and subtypes were well characterized, we found that the interaction between IgG and FcRn was not affected by the structure of the N-glycans attached to IgG. We also found that bovine FcRn binds IgG(2) better than IgG(1) , strongly suggesting that the role of FcRn in the bovine mammary gland is to recycle IgG(2) from the udder to blood, rather than to secrete IgG(1) into colostrum.     

Developmental and ultrastructual characteristics of mouse oocytes grown <Emphasis Type="Italic">in Vitro</Emphasis> from primordial germ cells

The aim of this study was to clarify the developmental and ultrastructual characteristics of oocytes grown in vitro from primordial germ cells. The female genital ridges at 12.5 days post coitus were cultured for 18 days on an insert membrane in Waymouth's MB752/1 medium, supplemented with 15% fetal bovine serum and 1 mM sodium pyruvate; subsequently, the follicles isolated from the tissue were cultured for eight days in Waymouth's medium supplemented with 5 microg/ml insulin, 5 microg/ml transferrin, 5 ng/ml selenium, 10 mIU/ml follicle stimulating hormone, and 100 ng/ml stem cell factor. The primordial germ cells developed in vitro into oocytes of more than 60 microm in diameter. The transmission electron microscopic analysis indicated that the oocytes, which developed in vitro, showed no obvious abnormality in their ultrastructure and had organelles appropriate for the oocyte size. However, a delay in the progressive changes of morphology in some of the organelles during oocyte growth was often found when comparing them to oocytes grown in vivo.