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1.
The presence of peptidergic neuronal networks in the brain and the modulating action of neuropeptides on brain functions as evidenced by their behavioral influence in particular support the concept that the brain like the peripheral endocrine glands is an endocrine target organ which is as sensitive to treatment with neuropeptides as the peripheral glands are to pituitary hormones. Animal and human data are reviewed showing that neuropeptides related to ACTH/MSH affect motivational and attentional processes and that those related to vasopressin are involved in memory processes. Since these functions decline during aging it is postulated that a decreased bioavailability of neuropeptides in brain of elderly people is associated with specific disturbances in mental performance. Thus, the decreased mental ability of the aged may be restored by treatment with neuropeptides particularly those with little, if any, peripheral, endocrine activity, like the ACTH neuropeptide Org 2766 and the vasopressin neuropeptide DGAVP. 相似文献
2.
Dependence creating properties of lipotropin C-fragment (beta-endorphin): evidence for its internal control of behavior 总被引:3,自引:0,他引:3
The C-fragment of lipotropin (β-endorphin) possesses reinforcing properties, in that this peptide, like heroin, induced intraventricular self-administering behavior in drug naive rats. Only mild behavioral signs reminiscent of physical dependence were present. After injection into the nucleus raphé magnus, C-Fragment appeared to act as a discriminative stimulus in rats trained to discriminate fentanyl from saline. These data indicate that naturally occuring C-Fragment exerts powerful control of behavior, which may be of significance for the understanding of the mechanisms underlying opiate dependence. 相似文献
3.
Hawon Lee Dae Haeng Cho Yong Hwan Kim Soo-Jeong Shin Sung Bong Kim Sung Ok Han Jinwon Lee Seung Wook Kim Chulhwan Park 《Biotechnology and Bioprocess Engineering》2011,16(4):755-760
The hydrolysis which converts polysaccharides to the fermentable sugars for yeast’s lingocellulosic ethanol production also
generates byproducts which inhibit the ethanol production. To investigate the extent to which inhibitory compounds affect
yeast’s growth and ethanol production, fermentations by Saccharomyces cerevisiae K35 were investigated in various concentrations of acetic acid, furfural, 5-hydroxymethylfurfural (5-HMF), syringaldehyde,
and coumaric acid. Fermentation in hydrolysates from yellow poplar and waste wood was also studied. After 24 h, S. cerevisiae K35 produced close to theoretically predicted ethanol yields in all the concentrations of acetic acid tested (1 ∼ 10 g/L).
Both furans and phenolics inhibited cell growth and ethanol production. Ethanol yield, however, was unaffected, even at high
concentrations, except in the cases of 5 g/L of syringaldehyde and coumaric acid. Although hydrolysates contain various toxic
compounds, in their presence, S. Cerevisiae K35 consumed close to all the available glucose and yielded more ethanol than theoretically predicted. S. Cerevisiae K35 was demonstrated to have high tolerance to inhibitory compounds and not to need any detoxification for ethanol production
from hydrolysates. 相似文献
4.
Jang do S Lee HJ Lee B Hong BH Cha HJ Yoon J Lim K Yoon YJ Kim J Ree M Lee HC Choi KY 《FEBS letters》2006,580(17):4166-4171
Failure to detect the intermediate in spite of its existence often leads to the conclusion that two-state transition in the unfolding process of the protein can be justified. In contrast to the previous equilibrium unfolding experiment fitted to a two-state model by circular dichroism and fluorescence spectroscopies, an equilibrium unfolding intermediate of a dimeric ketosteroid isomerase (KSI) could be detected by small angle X-ray scattering (SAXS) and analytical ultracentrifugation. The sizes of KSI were determined to be 18.7A in 0M urea, 17.3A in 5.2M urea, and 25.1A in 7M urea by SAXS. The size of KSI in 5.2M urea was significantly decreased compared with those in 0M and 7M urea, suggesting the existence of a compact intermediate. Sedimentation velocity as obtained by ultracentrifugation confirmed that KSI in 5.2M urea is distinctly different from native and fully-unfolded forms. The sizes measured by pulse field gradient nuclear magnetic resonance (NMR) spectroscopy were consistent with those obtained by SAXS. Discrepancy of equilibrium unfolding studies between size measurement methods and optical spectroscopies might be due to the failure in detecting the intermediate by optical spectroscopic methods. Further characterization of the intermediate using (1)H NMR spectroscopy and Kratky plot supported the existence of a partially-folded form of KSI which is distinct from those of native and fully-unfolded KSIs. Taken together, our results suggest that the formation of a compact intermediate should precede the association of monomers prior to the dimerization process during the folding of KSI. 相似文献
5.
Hydroxyl or peroxyl radicals and hypochlorous acid (HOCl) are known to cause the oxidation of lipoproteins. Here, we examined Cu2+-binding property of paraoxonase 1 (PON1), and antioxidant actions of peptides, resembling His residue-containing sequences in PON1, against oxidations by Cu2+, peroxyl radicals or HOCl. When Cu2+-binding property of PON1 was examined spectrophotometrically, the maximal Cu2+ binding was achieved at 1:1 molar ratio of PON1: Cu2+. Additionally, Cu2+-catalyzed oxidative inactivation of PON1 was prevented by Ca2+-depleted PON1 at 1:1 ratio, but not diethylpyrocarbonate (DEPC)-modified PON1, suggesting the participation of His residue in Cu2+-binding. When His-containing peptides were examined for antioxidant actions, those with either His residue at N-terminal position 2 or 3, or His-Pro sequence at C-terminal remarkably prevented Cu2+-mediated low density lipoprotein (LDL) oxidation and PON1 inactivation. Especially, FHKALY, FHKY or NHP efficiently prevented Cu2+-induced LDL oxidation (24 h), indicating a tight binding of Cu2+ by peptides. In support of this, the peptide/Cu2+ complexes exhibited a superoxide-scavenging activity. Separately, in oxidations by 2,2'-azobis-2-amidinopropane hydrochloride or HOCl, the presence of Tyrosine (Tyr) or Cysteine (Cys) residue markedly enhanced antioxidant action of His-containing peptides. These results indicate that His-containing peptides with Tys or Cys residues correspond to broad spectrum antioxidants in oxidation models employing Cu2+, 2,2'-azobis-2-amidinopropane hydrochloride (AAPH) or HOCl. 相似文献
6.
Molecular basis of the differences between normal and tumor tissues of gastric cancer 总被引:1,自引:0,他引:1
Yang S Shin J Park KH Jeung HC Rha SY Noh SH Yang WI Chung HC 《Biochimica et biophysica acta》2007,1772(9):1033-1040
To be able to describe the differences between the normal and tumor tissues of gastric cancer at a molecular level would be essential in the study of the disease. We investigated the gene expression pattern in the two types of tissues from gastric cancer by performing expression profiling of 86 tissues on 17K complementary DNA microarrays. To select for the differentially expressed genes, class prediction algorithm was employed. For predictor selection, samples were first divided into a training (n=58), and a test set (n=28). A group of 894 genes was selected by a t-test in a training set, which was used for cross-validation in the training set and class (normal or tumor) prediction in the test set. Smaller groups of 894 genes were individually tested for their ability to correctly predict the normal or tumor samples based on gene expression pattern. The expression ratios of the 5 genes chosen from microarray data can be validated by real time RT-PCR over 6 tissue samples, resulting in a high level of correlation, individually or combined. When a representative predictor set of 92 genes was examined, pathways of 'focal adhesion' (with gene components of THBS2, PDGFD, MAPK1, COL1A2, COL6A3), 'ECM-receptor interaction' pathway (THBS2, COL1A2, COL6A3, FN1) and 'TGF-beta signaling' (THBS2, MAPK1, INHBA) represent some of the main differences between normal and tumor of gastric cancer at a molecular level. 相似文献
7.
Edgar A. van der Grift Rodney van der Ree Lenore Fahrig Scott Findlay Jeff Houlahan Jochen A. G. Jaeger Nina Klar L. Francisco Madriñan Leif Olson 《Biodiversity and Conservation》2013,22(2):425-448
The last 20 years have seen a dramatic increase in efforts to mitigate the negative effects of roads and traffic on wildlife, including fencing to prevent wildlife-vehicle collisions and wildlife crossing structures to facilitate landscape connectivity. While not necessarily explicitly articulated, the fundamental drivers behind road mitigation are human safety, animal welfare, and/or wildlife conservation. Concomitant with the increased effort to mitigate has been a focus on evaluating road mitigation. So far, research has mainly focussed on assessing the use of wildlife crossing structures, demonstrating that a broad range of species use them. However, this research has done little to address the question of the effectiveness of crossing structures, because use of a wildlife crossing structure does not necessarily equate to its effectiveness. The paucity of studies directly examining the effectiveness of crossing structures is exacerbated by the fact that such studies are often poorly designed, which limits the level of inference that can be made. Without well performed evaluations of the effectiveness of road mitigation measures, we may endanger the viability of wildlife populations and inefficiently use financial resources by installing structures that are not as effective as we think they are. In this paper we outline the essential elements of a good experimental design for such assessments and prioritize the parameters to be measured. The framework we propose will facilitate collaboration between road agencies and scientists to undertake research programs that fully evaluate effectiveness of road mitigation measures. We discuss the added value of road mitigation evaluations for policy makers and transportation agencies and provide recommendations on how to incorporate such evaluations in road planning practices. 相似文献
8.
Grønning LM Wang JE Ree AH Haugen TB Taskén K Taskén KA 《Biology of reproduction》2000,62(4):1040-1046
In the testis, FSH has been shown to induce the expression and secretion of tissue inhibitor of metalloproteinases-1 (TIMP-1) from Sertoli cells in vitro. This study was performed to elucidate further the cellular origin of testicular TIMP-1 and its expression by hormonal and paracrine factors. This is the first report on the expression of testicular TIMP-1 in vivo. TIMP-1 mRNA in whole testis was decreased after hypophysectomy and strongly increased by the injection of FSH-S17 to hypophysectomized rats. Primary cultures of both peritubular and Sertoli cells showed basal expression of TIMP-1 mRNA. In contrast, we were unable to detect TIMP-1 mRNA in Leydig cells, freshly isolated immature germ cells (primary spermatocytes and spermatids), or residual bodies. We further show that treatment of Sertoli cells with 8-(4-chlorophenyl)thio-cAMP (8-CPTcAMP) in combination with 12-O-tetradecanoylphorbol 13-acetate (TPA) or Ca(2+) inducers (calcium ionophore A23187 or thapsigargin) had additive (TPA) and synergistic effects (Ca(2+)) on the level of TIMP-1 mRNA and secreted protein. We also show that both the level of TIMP-1 mRNA and secreted protein from Sertoli cells were strongly increased by residual bodies, as well as by the cytokine interleukin-1alpha. TIMP-1 was not up-regulated by either 8-CPTcAMP or interleukin-1alpha in peritubular cells. In contrast to the regulated secretory fraction of TIMP-1, we also detected constitutively expressed immunoreactive TIMP-1 in the nucleus of Sertoli cells, suggesting a role of nuclear TIMP-1 in these cells. In conclusion, our data show that secretion of TIMP-1 from Sertoli cells is highly regulated by hormonal and local processes in the testis, indicating that TIMP-1 is of physiological importance during both testicular development and spermatogenesis. 相似文献
9.
10.
Degree of landscape fragmentation influences genetic isolation among populations of a gliding mammal
Forests and woodlands are under continuing pressure from urban and agricultural development. Tree-dependent mammals that rarely venture to the ground are likely to be highly sensitive to forest fragmentation. The Australian squirrel glider (Petaurus norfolcensis) provides an excellent case study to examine genetic (functional) connectivity among populations. It has an extensive range that occurs in a wide band along the east coast. However, its forest and woodland habitat has become greatly reduced in area and is severely fragmented within the southern inland part of the species' range, where it is recognised as threatened. Within central and northern coastal regions, habitat is much more intact and we thus hypothesise that genetic connectivity will be greater in this region than in the south. To test this we employed microsatellite analysis in a molecular population biology approach. Most sampling locations in the highly modified south showed signatures of genetic isolation. In contrast, a high level of genetic connectivity was inferred among most sampled populations in the more intact habitat of the coastal region, with samples collected 1400 km apart having similar genetic cluster membership. Nonetheless, some coastal populations associated with urbanisation and agriculture are genetically isolated, suggesting the historic pattern observed in the south is emerging on the coast. Our study demonstrates that massive landscape changes following European settlement have had substantial impacts on levels of connectivity among squirrel glider populations, as predicted on the basis of the species' ecology. This suggests that landscape planning and management in the south should be focused on restoring habitat connectivity where feasible, while along the coast, existing habitat connectivity must be maintained and recent losses restored. Molecular population biology approaches provide a ready means for identifying fragmentation effects on a species at multiple scales. Such studies are required to examine the generality of our findings for other tree-dependent species. 相似文献