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41.
42.
Andrew SF Dinh TT Ritter S 《American journal of physiology. Regulatory, integrative and comparative physiology》2007,292(5):R1792-R1798
Glucose is required for brain energy metabolism. Decerebration, aqueduct occlusion, and cannula mapping studies have established that glucose-sensing cells capable of eliciting feeding and adrenal medullary responses to glucoprivation are localized in the hindbrain. Glucoprivation also evokes corticosterone and glucagon secretion, but the location of receptors mediating these responses is unknown. To determine whether glucoreceptive sites controlling these responses are present in the hindbrain, we administered the antiglycolytic agent, 5-d-thioglucose (5TG, 24 microg in 200 nl) into brain stem sites through implanted cannulas and examined plasma concentrations of corticosterone and glucagon. Both hindbrain and hypothalamic sites were tested. Blood was collected remotely from intra-atrial catheters at 0, 30, 60, 90, 120, 180, and 240 min after 5TG or control injection. Caudal hindbrain 5TG injections potently increased circulating corticosterone and glucagon concentrations. For corticosterone, the mean peak response (maximum concentration minus time 0 concentration) elicited at positive sites (23 of 40 sites) was 391 ng/ml (SE = 16). For glucagon, the mean peak response at positive sites (27 of 40 sites) was 46 pg/ml (SE = 6). Glucoprivically evoked glucagon secretion was abolished by the ganglionic blocker, hexamethonium, but not by adrenal denervation. Six of twenty-five hypothalamic sites were positive for corticosterone secretion, yielding plasma levels of 279 +/- 23 ng/ml, but none of the hypothalamic injection sites elevated glucagon concentrations. Results demonstrate that receptor cells responsive to glucose deficit and capable of increasing corticosterone and glucagon concentrations exist within the hindbrain, thus further delineating central glucoregulatory neural circuitry. 相似文献
43.
miR172 regulates stem cell fate and defines the inner boundary of APETALA3 and PISTILLATA expression domain in Arabidopsis floral meristems 总被引:5,自引:0,他引:5
In Arabidopsis, two floral homeotic genes APETALA2 (AP2) and AGAMOUS (AG) specify the identities of perianth and reproductive organs, respectively, in flower development. The two genes act antagonistically to restrict each other to their proper domains of action within the floral meristem. In addition to AG, which antagonizes AP2, miR172, a microRNA, serves as a negative regulator of AP2. In this study, we showed that AG and miR172 have distinct functions in flower development and that they largely act independently in the negative regulation of AP2. We uncovered functions of miR172-mediated repression of AP2 in the regulation of floral stem cells and in the delineation of the expression domain of another class of floral homeotic genes. Given the antiquity of miR172 in land plants, our findings have implications for the recruitment of a microRNA in the building of a flower in evolution. 相似文献
44.
A newly isolated gene from Ralstonia sp. M1, encoding an esterase, was cloned in Escherichia coli and its nucleotide sequence determined. The 1.6kb insert revealed one complete open reading frame, predicted to encode an esterase (320 aa, 34.1kDa) with a pI of 9.86. EstR contained a putative oxyanion hole H36G37, a conserved pentapeptide G103HSLG107 and a conserved catalytic His265 and Asp237. The EstR sequence shared 64-70 and 44-48% identity with the hydrolases/acyltransferases from Burkholderia strains and from Ralstonia strains, respectively, 44 and 38% identity with the lactone-specific esterase from Pseudomonas fluorescens and Mesorhizobium loti, respectively. The esterase EstR was expressed with a high level of 41mg/g wet cells. The Ni-NTA-purified esterase EstR showed an optimal activity in the temperature range 60-65 degrees C and pH range 7.5-9.0 towards p-nitrophenyl caproate. The enzyme was found to be highly resistant to many organic solvents especially induced by ethanolamine. Metal ions showed slight effect on esterase activity. The inhibitor phenylmethanesulfonyl fluoride inhibited strongly the esterase. Triton X-45 induced the activation of EstR, but other detergents slightly to strongly decreased or completely inhibited. Among tested p-NP esters, caproate was the most preferential substrate of this esterase. 相似文献
45.
Mesenchymal Stem Cells from Rat Bone Marrow Downregulate Caspase-3-mediated Apoptotic Pathway After Spinal Cord Injury in Rats 总被引:6,自引:0,他引:6
Mesenchymal stem cells have been intensively studied for their potential use in reparative strategies for neurodegenerative
diseases and traumatic injuries. We used mesenchymal stem cells (rMSC) from rat bone marrow to evaluate the therapeutic potential
after spinal cord injury (SCI). Immunohistochemistry confirmed a large number of apoptotic neurons and oligodendrocytes in
caudal segments 2 mm away from the lesion site. Expression of caspase-3 on both neurons and oligodendrocytes after SCI was
significantly downregulated by rMSC. Caspase-3 downregulation by rMSC involves increased expression of FLIP and XIAP in the
cytosol and inhibition of PARP cleavage in the nucleus. Animals treated with rMSC had higher Basso, Beattie, Bresnahan (BBB)
locomotor scoring and better recovery of hind limb sensitivity. Treatment with rMSC had a positive effect on behavioral outcome
and histopathological assessment after SCI. The ability of rMSC to incorporate into the spinal cord, differentiate and to
improve locomotor recovery hold promise for a potential cure after SCI.
Special issue in honor of Naren Banik. 相似文献
46.
47.
Suppression of gene expression by small interfering RNA (siRNA) has proved to be a gene-specific and cost effective alternative
to other gene suppression technologies. Short hairpin RNAs (shRNAs) generated from the vector-based expression are believed
to be processed into functional siRNAs in vivo, leading to gene silencing. Since an shRNA library carries a large pool of potential siRNAs, such a library makes it possible
to knock down gene expression at the genome wide scale. Although much of research has been focused on generating shRNA libraries
from either individually made gene specific sequences or cDNA libraries, there is no report on constructing randomized shRNA
libraries, which could provide a good alternative to these existing libraries. We have developed a method of constructing
shRNAs from randomized oligonucleotides. Through this method, one can generate a partially or fully randomized shRNA library
for various functional analyses. We validated this procedure by constructing a p53-specific shRNA. Western blot revealed that
the p53-shRNA successfully suppressed expression of the endogenous p53 in MCF-7 cells. We then made a partially randomized
shRNA library. Sequencing of 15 randomly picked cloned confirmed the randomness of the library. Therefore, the library can
be used for various functional assays, such as target validation when a suitable screening or selection method is available. 相似文献
48.
Binh Tran Quang Linh Duong Tuan Chung Le Thi Kim Phuong Pham Tran Nga Bui Thi Thuy Ngoc Nguyen Anh Thuyen Tran Quang Tung Do Dinh Nhung Bui Thi 《Biochemical genetics》2022,60(2):707-719
Biochemical Genetics - The study aimed to evaluate the contribution of the FTO A/T polymorphism (rs9939609) to the prediction of the future type 2 diabetes (T2D). A population-based prospective... 相似文献
49.
Nguyen Anh T. Q. Nguyen Anh M. Nguyen Muu T. Nguyen Hue T. Duong Lim T. Dinh Van M. Nguyen Phuong M. Dultz Stefan Nguyen Minh N. 《Biogeochemistry》2022,160(1):35-47
Biogeochemistry - Phytolith is widely known as a silica structure in numerous silicon (Si) accumulator plants, e.g., rice, and it contains various nutrients and other beneficial elements. When rice... 相似文献
50.
Chia-Chun Yu Shih-Ping Liu Jui-Ling Hsu John TA Hsu Konstantin V Kudryavtsev Jih-Hwa Guh 《Journal of biomedical science》2015,22(1)