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991.
Fecal testosterone and cortisol levels in six wild male Japanese macaques (Macaca fuscata), three of high rank and three of low, were analyzed to investigate the hormonal correlates of rank, reproduction, and female-directed aggression. The study encompassed the 6-month mating season, from October 1999 to March 2000, during which time 251 fecal samples and approximately 550 h of behavioral data were collected. Dominant males were not found to differ from subordinate males in overall rates of aggressive or copulatory behavior. Likewise, testosterone excretion, which peaked in the early part of the mating season and declined gradually thereafter, did not differ significantly by rank. High-ranking males, however, were observed to excrete significantly higher levels of cortisol than low-ranking males, suggesting that dominance may carry costs. The two hormones were found to be inversely correlated in the two most dominant males, but independent in all others. Rate of noncontact aggression was significantly correlated with testosterone, while no significant relationships were observed between testosterone and contact aggression nor any aspect of copulatory behavior. These data further support the contention that social subordinance and stress are not inexorably linked, as well as suggest that elevated glucocorticoid concentrations in high-ranking males may reflect increased metabolic costs associated with dominant male reproductive strategy. 相似文献
992.
Effect of hemorrhagic shock on apoptosis and energy-dependent efflux system in the brain 总被引:3,自引:0,他引:3
Recent findings suggest that apoptosis, which contributes to neuronal damage after ischemic injury, may play a role in sequelae associated with severe blood loss. This study examined the effect of hemorrhage and resuscitation on the expression (in situ hybridization and computerized image analysis) of bcl-2 mRNA, which codes for a protein that inhibits apoptosis, and mdr1 mRNA, which codes for a glycoprotein marker for drug efflux from the brain. Anaesthetized rats were subjected to volume-controlled (15 mL/kg) hemorrhage followed by resuscitation with shed blood (BR) or nonresuscitated (NR); control animals had femoral artery cannulation only (SHAM). Following 24 hr blood loss, distinctly lower levels of bcl-2 gene expression were observed in dentate gyrus of NR rats (0.25 ± 0.04) as compared to SHAM rats (0.52 ± 0.07); suscitation with shed blood prevented this reduction (0.58 ± 0.05). Similar results were observed in cortex, striatum, and hypothalamus. Also, mdr1 mRNA levels were significantly reduced in all brain areas of the NR group as compared to the BR and SHAM groups. The findings suggest that blood resuscitation suppressed apoptosis and protected against loss of energy-dependent efflux system in the brain in response to hemorrhage. 相似文献
993.
994.
Kimiko Saka Maki Tadenuma Shinsuke Nakade Noriko Tanaka Hideaki Sugawara Ken Nishikawa Nobuyuki Ichiyoshi Masanari Kitagawa Hirotada Mori Naotake Ogasawara Akiko Nishimura 《DNA research》2005,12(1):63-68
To facilitate genetic studies of Escherichia coli, we constructed a complete set of mobile plasmid clones of intact open reading frames (ORFs). Their expression is strictly controlled by Ptac / lacI(q). The plasmids carrying each ORF were introduced into an F+ recA strain and stored in 96-well microtiter plates. In this way, 96 clones can be transferred simultaneously to F- bacteria using the conjugative system. This provides a convenient procedure for systematic identification of ORFs that suppress or complement mutations. We created two types of clone sets: the original set contained individual clones in 45 microtiter plates, and a second set contained pools of 48 clones stored in a single microtiter plate. Using these clone sets, we have identified 403 genes that can correct in trans the temperature-sensitive defect of cell division mutants, which would suggest multiple global regulators for bacterial cell division. 相似文献
995.
Y Hu J Komoto Y Huang T Gomi H Ogawa Y Takata M Fujioka F Takusagawa 《Biochemistry》1999,38(26):8323-8333
The crystal structure of rat liver S-adenosyl-L-homocysteine hydrolase (AdoHcyase, EC 3.3.1.1) which catalyzes the reversible hydrolysis of S-adenosylhomocysteine (AdoHcy) has been determined at 2.8 A resolution. AdoHcyase from rat liver is a tetrameric enzyme with 431 amino acid residues in each identical subunit. The subunit is composed of the catalytic domain, the NAD+-binding domain, and the small C-terminal domain. Both catalytic and NAD+-binding domains are folded into an ellipsoid with a typical alpha/beta twisted open sheet structure. The C-terminal section is far from the main body of the subunit and extends into the opposite subunit. An NAD+ molecule binds to the consensus NAD+-binding cleft of the NAD+-binding domain. The peptide folding pattern of the catalytic domain is quite similar to the patterns observed in many methyltransferases. Although the crystal structure does not contain AdoHcy or its analogue, there is a well-formed AdoHcy-binding crevice in the catalytic domain. Without introducing any major structural changes, an AdoHcy molecule can be placed in the catalytic domain. In the structure described here, the catalytic and NAD+-binding domains are quite far apart from each other. Thus, the enzyme appears to have an "open" conformation in the absence of substrate. It is likely that binding of AdoHcy induces a large conformational change so as to place the ribose moiety of AdoHcy in close proximity to the nicotinamide moiety of NAD+. A catalytic mechanism of AdoHcyase has been proposed on the basis of this crystal structure. Glu155 acts as a proton acceptor from the O3'-H when the proton of C3'-H is abstracted by NAD+. His54 or Asp130 acts as a general acid-base catalyst, while Cys194 modulates the oxidation state of the bound NAD+. The polypeptide folding pattern of the catalytic domain suggests that AdoHcy molecules can travel freely to and from AdoHcyase and methyltransferases to properly regulate methyltransferase activities. We believe that the crystal structure described here can provide insight into the molecular architecture of this important regulatory enzyme. 相似文献
996.
997.
L-Pipecolic acid was found to be effective in inducing floweringof Lemna paucicostata 151, 381, 441 and 6746, and of Lemna gibbaG3. When the plants were grown on half-strength Hutner's medium,L-pipecolic acid caused profuse flowering of L. paucicostata151 maintained under 9 and 10 h of light daily. In L. paucicostata441 and 6746, L-pipecolic acid had a strong flower-promotingeffect under a near critical photoperiod. In L. paucicostata381, by contrast, L-pipecolic acid had only a very small effecton flowering. In L. gibba G3 substantial promotion of floweringwas observed under continuous light. When one-twentieth-strengthHutner's medium was used as the basic medium, L-pipecolic acidstimulated flowering in all strains of Lemna examined, evenunder continuous light. When L. paucicostata 151 was grown on one-tenth-strength M mediumor one-twentieth-strength Hutner's medium, the flower-inducingactivity of L-pipecolic acid was greatly enhanced by cytokininunder continuous light. However, when this strain was grownwith 9 h of illumination daily, this synergistic effect of cytokininwas only slight. A short-term (even 1-h) treatment with L-pipecolicacid resulted in flowering, suggesting that L-pipecolic acidis involved in the induction of flowering, rather than its evocation.D-Pipecolic acid also had flower-inducing activity, but itsactivity was 50 times lower than that of the L-isomer. (Received January 23, 1992; Accepted March 9, 1992) 相似文献
998.
999.
L. Wijayanti S. Fujioka M. Kobayashi A. Sakurai 《Journal of Plant Growth Regulation》1997,16(2):115-119
The involvement of abscisic acid (ABA) and indole-3-acetic acid (IAA) in the regulation of flowering of Pharbitis nil was investigated through exogenous applications and analyses of endogenous levels. Both hormones inhibited the flowering
of P. nil when they were applied before or after a single 15-h dark treatment. The inhibitory effect of ABA and IAA was significant
when they were applied before the dark treatment, and the application to plumules was more effective than that to cotyledons.
In all applications, the inhibitory effect of IAA was stronger than that of ABA. Endogenous levels of ABA and IAA in the plumules
were compared between flower-inductive (15-h dark treatment) and noninductive (continuous light) light conditions. There was
no significant difference in the ABA level between light and dark conditions, whereas the level of IAA was decreased by the
dark treatment. These results suggest that biosynthesis and/or catabolism of IAA is affected by the light treatment and therefore
may be involved in the regulation of early flowering processes in the apex. The inhibitory effects of ABA and IAA were reversed
by an application of gibberellin A3, indicating that gibberellin A3 counteracts the flowering processes affected by ABA and IAA. Application of aminoethoxyvinylglycine restored the flowering
response inhibited by IAA, which suggests the possibility that the inhibitory effect of IAA is the result of enhanced ethylene
biosynthesis.
Received November 22, 1996; accepted February 17, 1997 相似文献
1000.
ADAM is a recently discovered gene family that encodes proteins with a disintegrin and metalloproteinase. ADAMTS-1 is a gene encoding a new member protein of the ADAM family with the thrombospondin (TSP) type I motif, the expression of which is associated with inflammatory processes. In the present study, we have characterized the exon/intron organization of the mouse ADAMTS-1 gene. The ADAMTS-1 gene is composed of nine exons, all of which are present within the 9.2-kb genomic region. Among the nine exons, exons 1, 5, and 6 encode a proprotein domain, a disintegrin-like domain, and a TSP type I motif, respectively, of the ADAMTS-1 protein, suggesting that there is a correlation between exon/intron organization and functional domains. In addition, the exon/ intron organization of the ADAMTS-1 gene is very different from that of the metalloproteinase-like/disintegrin-like/cysteine-rich protein gene (MDC) (ADAM11), suggesting that the genomic structure of ADAM family genes is not necessarily conserved. Furthermore, fluorescencein situhybridization revealed that the ADAMTS-1 gene is located in region C3–C5 of chromosome 16, to which none of the previously identified ADAM genes have been mapped. 相似文献