Improvement of follicular development rather than gonadotrophin secretion by thyroxine treatment in infertile immature hypothyroid rdw rats

Despite extensive study of reproductive abnormalities in female hypothyroid animals, little is known of folliculogenesis and gonadotrophin secretion in spontaneously hypothyroid animals, especially in response to exogenous hormone treatment. In this study, follicular development and plasma hormone concentrations in the presence or absence of thyroxine and eCG treatment were investigated in infertile immature spontaneously hypothyroid rdw rats. Administration of thyroxine once a day from day 21 to day 29 after birth resulted in increases in body weight (P < 0.001) and ovary mass on day 30 (P < 0.01). Similar populations of both healthy and atretic antral follicles ranging from 101 to 400 micrometer in diameter were observed in control rdw and normal rats. In rdw rats, thyroxine treatment markedly increased the number of healthy antral uniovular follicles 101-400 or > 550 micrometer in diameter in the absence or presence of eCG, respectively. Combined treatment of thyroxine and eCG in rdw rats also markedly increased the number of healthy antral biovular follicles. Thyroxine treatment did not affect the population of atretic antral follicles, but resulted in decrease in the number of atretic large antral follicles (> 400 microm) in the presence of eCG. Plasma oestradiol concentrations in rdw rats given both thyroxine and eCG were significantly higher than they were in rdw rats given eCG alone (P < 0.001). There were no significant differences in plasma FSH concentrations on day 28 between rdw (10.7 +/- 1.6 ng ml(-1)) and normal rats (12.0 +/- 1.4 ng ml(-1); P > 0. 05). Although there were no significant differences in plasma LH concentrations between control rdw (1.9 +/- 0.1 ng ml(-1)) and normal rats on day 30 (1.8 +/- 0.1 ng ml(-1); P > 0.05), eCG treatment increased plasma LH to a peak concentration 52 h after injection in normal (24.9 +/- 2.4 ng ml(-1)) but not in rdw rats treated with thyroxine (4.8 +/- 0.3 ng ml(-1); P < 0.05). In conclusion, the results of the present study indicate that thyroxine treatment improves follicular development but does not rescue the defect of the preovulatory surge of LH in eCG-primed rdw rats.     

Design and Evaluation of Useful Bacterium-Specific PCR Primers That Amplify Genes Coding for Bacterial 16S rRNA

We report the design and evaluation of PCR primers 63f and 1387r for amplification of 16S rRNA genes from bacteria. Their specificity and efficacy were tested systematically with a variety of bacterial species and environmental samples. They were found to be more useful for 16S rRNA gene amplification in ecological and systematic studies than PCR amplimers that are currently more generally used.     

Induction of Differentiation and Apoptosis in Human Promyelocytic Leukemia HL60 Cell Line by a New Type of Steroids

Mer-NF8054X is a new type of steroid whose structure has been established as 11-oxo-18, 22-cycloergosta-6, 8(14)-diene-3β, 5β, 9β, 23S-tetraol (an 18, 22-cycloergostane), which has been reported to have antifungal activity againstAspergillus fumigatus.However, other biological activities are unknown. Herein, we reported that Mer-NF8054X inhibited cell growth of HL60 human leukemia cells, when used either singly or in combination with retinoic acid (RA). In addition, Mer-NF8054X alone induced differentiation and apoptosis of HL60 cells. The induction of differentiation of HL60 cells by Mer-NF8054X was synergistic in combination with RA. On the other hand, Emesterone A, an analogue of Mer-NF8054X which is missing a hydroxy residue from the third position, showed much lower activity than Mer-NF8054X on the inhibition of cell growth and the induction of cell differentiation and apoptosis. However, Emesterone B, an analogue of Emesterone A which is missing a hydroxy residue from the fifth position, showed higher activity than Emesterone A but lower activity than Mer-NF8054X when examined for the inhibition of cell growth and the induction of cell differentiation and apoptosis. These results suggested that Mer-NF8054X and its analogs may be a new type of differentiation inducing agent. The hydroxy residue at the third position or fifth position in Mer-NF8054X may be necessary, but not essential, for inhibition of growth and induction of both differentiation and apoptosis of HL60 cells. In addition, Mer-NF8054X enhanced the differentiation of HL60 cells induced by RA. Based on these results, Mer-NF8054X may have utility in the clinic in combination with RA for leukemia patients.     

CO binding studies of nitric oxide synthase: effects of the substrate, inhibitors and tetrahydrobiopterin

The dissociation constant (K_d) for CO from neuronal nitric oxide synthase heme in the absence of the substrate and cofactor was less than 10⁻³ μM. In the presence of

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-Arg, it dramatically increased up to 1 μM. In the presence of inhibitors such as N^G-nitro-

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-arginine methyl ester and 7-nitroindazole (NI), the K_d value further increased up to more than 100 μM. Addition of the cofactor, 5,6,7,8-tetrahydrobiopterin (H₄B), increased the K_d value by 10-fold in the presence of

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-Arg, whereas it decreased the value to less than one 250th in the presence of NI. Addition of H₄B increased the recombination rate constant (k_on) for CO by more than two-fold in the presence of

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-Arg or N⁶-(1-iminoethyl)-

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-lysine, whereas it decreased the k_on value by three-fold in the presence of

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-thiocitrulline. Thus, the binding fashion of some of inhibitors, such as NI, may be different from that of

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-Arg with respect to the H₄B effect.     

Effect of ruthenium precursor on hydrogen-treated active carbon supported ruthenium catalysts for ammonia synthesis

Active carbon (A.C.), after treatment at 1123 K with hydrogen for more than 24 h, was found to be very effective as a support for ruthenium catalysis in ammonia synthesis. The activity of barium promoted Ru catalysts supported on this treated A.C. is affected remarkably by the Ru precursor. Ru₃(CO)₁₂ was found previously to be the most effective Ru precursor for oxide supports such as Al₂O₃, MgO, and CeO₂ in ammonia synthesis. However, in this study, the Ru---Bao/A.C. catalyst prepared from Ru(acac)₃ was found to yield the highest activity, while the catalyst prepared from Ru₃(CO)₁₂ resulted in the lowest activity among several precursors. Transmission electron microscopy and hydrogen chemisorption showed that the particle size of Ru obtained from the decomposition of Ru(acac)₃ on hydrogen-treated A.C. is smaller than the particle size of Ru obtained from the decomposition of Ru₃(CO)₁₂. Additionally, RuCl₃ was found to be an effective precursor for Ru/A.C. catalyst. It has been suggested that chlorine ions can be removed easily from A.C. by hydrogen reduction at 773 K, and that this results in the high activity.     

Phe-X-Pro-Arg-Leu-NH(2) peptide producing cells in the central nervous system of the silkworm,Bombyx mori

Members of the neuropeptide family having Phe-X-Pro-Arg-Leu-NH(2) (FXPRLamide; X=Ser, Thr, Val, or Gly) at the C-terminus serve as regulators of oviduct and visceral muscle contraction, sex pheromone production, and diapause induction. Antibody raised against Bombyx mori diapause hormone recognized a variety of FXPRLamide peptides. Using this antibody, the antigen was immunocytochemically localized in the central nervous system (CNS) of the silkworm, Bombyx mori. Immunoreactive somata were observed in all ganglia of the CNS including the brain. Twelve somata localized at the midline of the suboesophageal ganglion (SG) were most intensely stained, and their neurite projections reached the retrocerebral complex. Thus, these cells in the SG exhibited typical features of neuroendocrine neurons. Marked reduction in immunoreactivity was observed in a pair of neurosecretory cells in the labial neuromere in SG of diapause type pupae, which indicates an active release of FXPRLamide peptides from these cells. No clear connection to neurohemal sites were observed in immunoreactive cells in the brain, thoracic or abdominal ganglia, suggesting that the immunoreactive peptides in these organs are likely to serve as neurotransmitters or neuromodulators.     

Ribosomal proteins in the cyanobacterium Anabaena variabilis strain M3: presence of L25 protein

Ribosomal proteins from a cyanobacterium Anabaena variabilis were analyzed by two-dimensional gel electrophoresis. We detected 21 protein spots of the small subunit and 29 protein spots of the large subunit. One of the spots was identified as L25 protein, which suggests that the reading frame sll1824 of Synechocystis is the L25 protein.     

Measurement of early pregnancy factor activity for monitoring the viability of the equine embryo

The viability of embryos before flushing from donor mares (n = 5) and after transfer to recipient mares (n = 7) was monitored in mare serum by detecting early pregnancy factor (EPF) using the rosette inhibition test (RIT). The EPF activity was measured in donor mares before and after natural mating at natural estrus; after ovulation on Days 2, 5 and 8; and after embryo flushing (Day 8) on Days 8, 9, 10 and 13 after ovulation. The collected embryos were transferred immediately after flushing. The EPF activity in recipient mares were measured on the day of transfer and after embryo transfer on Days 1, 2, 3 and 5. Pregnancy was confirmed on Day 12 to 14 after embryo transfer. The mean EPF activity of donor mares was increased to the pregnant level (> an RI titer score of 10) on Day 2 after ovulation. Two days after flushing the embryos, the EPF activity of donor mares had decreased to the nonpregnant level. Among the 7 recipient mares, 3 mares were diagnosed pregnant on Day 12 after embryo transfer with ultrasound. The EPF activity of the pregnant recipient mares was increased above the minimum level observed in pregnant mares on Days 2 to 3 after transfer. However, among the nonpregnant recipient mares after embryo transfer, the EPF activity of 3 mares remained at the pregnant level only 2 to 3 d and then declined to the nonpregnant level. In one recipient mare, EPF activity did not reach the pregnant level throughout the sample collection. The results of this study indicated that equine EPF can be detected in serum of pregnant mares as early as Day 2 after ovulation. From our observation, we conclude that the measurement of EPF activity is useful for monitoring the in vivo viability of equine embryos and early detection of embryonic death.     

Presenilin 1 Mutations Linked to Familial Alzheimer's Disease Increase the Intracellular Levels of Amyloid β-Protein 1–42 and Its N-Terminally Truncated Variant(s) Which Are Generated at Distinct Sites

Abstract: Mutations in the presenilin genes PS1 and PS2 cause the most common form of early-onset familial Alzheimer's disease. The influence of PS1 mutations on the generation of endogenous intracellular amyloid β-protein (Aβ) species was assessed using a highly sensitive immunoblotting technique with inducible mouse neuro-blastoma (Neuro 2a) cell lines expressing the human wild-type (wt) or mutated PS1 (M146L or Δexon 10). The induction of mutated PS1 increased the intracellular levels of two distinct Aβ species ending at residue 42 that were likely to be Aβ1–42 and its N-terminally truncated variant(s) Aβx-42. The induction of mutated PS1 resulted in a higher level of intracellular Aβ1–42 than of intracellular Aβx-42, whereas extracellular levels of Aβ1–42 and Aβx-42 were increased proportionally. In addition, the intracellular generation of these Aβ42 species in wt and mutated PS1 -induced cells was completely blocked by brefeldin A, whereas it exhibited differential sensitivities to monensin: the increased accumulation of intracellular Aβx-42 versus inhibition of intracellular Aβ1–42 generation. These data strongly suggest that Aβx-42 is generated in a proximal Golgi, whereas Aβ1–42 is generated in a distal Golgi and/or a post-Golgi compartment. Thus, it appears that PS1 mutations enhance the degree of 42-specific γ-secretase cleavage that occurs in the normal β-amyloid precursor protein processing pathway (a) in the endoplasmic reticulum or the early Golgi apparatus prior to β-secretase cleavage or (b) in the distinct sites where Aβx-42 and Aβ1–42 are generated.