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排序方式: 共有105条查询结果,搜索用时 437 毫秒
81.
Seventy-five pairs of ovaries from Yankasa Sheep aged 1 1 2 to 3 years were collected from a Zaria abattoir for 12 months, to study the ovarian activity. It was observed that ovarian activity in Yankasa sheep was year-round with maximum activity occurring during the rainy and pre-rain seasons. These periods of maximum ovarian activity might be caused by the availability of pasture during the rainy and pre-rain seasons, since Nigerian sheep obtain most of their food by grazing available pasture. 相似文献
82.
Ovarian activity of Sokoto red goats was studied for 12 months using 141 pairs of ovaries obtained from a Zaria abattoir. Ovarian activity occurred throughout the year but higher activity was observed during the rainy (June to September) and dry (January to March) seasons. The higher ovarian activity during the rainy season is perhaps due to the availability of pasture during this time, while the higher activity during the dry season might be related to the goat's ability to convert leaves and dry forage that are mostly available during this season into useful nutrients. Temperature increase, particularly during the dry season, might be a factor for higher ovarian activity during the same period. 相似文献
83.
Age-stiffening of ocular tissues is statistically linked to glaucoma in the elderly. In this study, the effects of age-stiffening on the lamina cribrosa, the primary site of glaucomatous nerve damages, were modeled using computational finite element analysis. We showed that glaucomatous nerve damages and peripheral vision loss behavior can be phenomenologically modeled by shear-based damage criterion. Using this damage criterion, the potential vision loss for 30 years old with mild hypertension of 25mmHg intraocular pressure (IOP) was estimated to be 4%. When the IOP was elevated to 35mmHg, the potential vision loss rose to 45%; and age-stiffening from 35 to 60 years old increased the potential vision loss to 52%. These results showed that while IOP plays a central role in glaucomatous damages, age-stiffening facilitates glaucomatous damages and may be the principal factor that resulted in a higher rate of glaucoma in the elderly than the general population. 相似文献
84.
Lead levels were determined in the blood, scalp hair and fingernails of 38, all male auto-mechanics (aged 18-45 years) from Abeokuta, South-western Nigeria. The subjects were classified into four sub-groups based on the period of exposure namely: 1-5, 6-10, 11-15, and >16 years. Thirty-two occupationally unexposed subjects (mainly office workers) served as the control. The weight, height and body mass indexes of all subjects were noted, in addition to other information obtained through structured questionnaire. The mean values of blood lead (BPb), hair lead (HPb) and fingernail lead (NPb) of the occupationally exposed subjects (n=38) were 48.50 +/- 9.08 microg/dL, 17.75 +/- 5.16 microg/g, and 5.92 +/- 3.30 microg/g respectively, while the corresponding mean values for these parameters in the control subjects (n = 32) were 33.(,5 +/- 10.09 microg/dL, 14.30 +/- 5.90 microg/g and 5.31 +/- 2.77 microg/g respectively. The differences in BPb and HPb levels of the two groups were statistically significant (P <0.05 and P <0.01 respectively), while that of NPb was not significant. The levels of lead in the biological samples appeared to have no relationship with the number of years on the job. From these results, it was obvious that the higher levels of lead in the biological samples of test subjects, compared with those of the controls were from environmental sources. 相似文献
85.
Titilayo Omolara Johnson Oluwafemi Adeleke Ojo Soala Ikiriko Jesuseyifunmi Ogunkua Gaius Olorunfemi Akinyemi Damilare Emmanuel Rotimi Jane-Rose Oche Abayomi Emmanuel Adegboyega 《Biochemistry and Biophysics Reports》2021
Acetylcholinesterase (AChE) has been an effective target for insecticide development which is a very important aspect of the global fight against insect-borne diseases. The drastic reduction in the sensitivity of insects to AChE-targeting insecticides like organophosphates and carbamates have increased the need for insecticides of natural origin. In this study, we used Drosophila melanogaster as a model to investigate the insecticidal and AChE inhibitory potentials of Cymbopogon citratus and its bioactive compounds. Flies were exposed to 100 and 200 mg/mL C. citratus leaf extract for a 3-h survival assay followed by 45 min exposure for negative geotaxis and biochemical assays. Molecular docking analysis of 45 bioactive compounds of the plant was conducted against Drosophila melanogaster AChE (DmAChE). Exposure to C. citratus significantly reduced the survival rate of flies throughout the exposure period and this was accompanied by a significant decrease in percentage negative geotaxis, AChE activity, catalase activity, total thiol level and a significant increase in glutathione-S-transferase (GST) activity. The bioactive compounds of C. citratus showed varying levels of binding affinities for the enzyme. (+)-Cymbodiacetal scored highest (?9.407 kcal/mol) followed by proximadiol (?8.253 kcal/mol), geranylacetone (?8.177 kcal/mol), and rutin (?8.148 kcal/mol). The four compounds occupied the same binding pocket and interacted with important active site amino acid residues as the co-crystallized ligand (1qon). These compounds could be responsible for the insecticidal and AChE inhibitory potentials of C. citratus and they could be further explored in the development of AChE-targeting insecticides. 相似文献
86.
Chang Yu Jun Yu Xiaotian Yao William KK Wu Youyong Lu Senwei Tang Xiangchun Li Li Bao Xiaoxing Li Yong Hou Renhua Wu Min Jian Ruoyan Chen Fan Zhang Lixia Xu Fan Fan Jun He Qiaoyi Liang Hongyi Wang Xueda Hu Minghui He Xiang Zhang Hancheng Zheng Qibin Li Hanjie Wu Yan Chen Xu Yang Shida Zhu Xun Xu Huanming Yang Jian Wang Xiuqing Zhang Joseph JY Sung Yingrui Li Jun Wang 《Cell research》2014,24(6):701-712
Single-cell sequencing is a powerful tool for delineating clonal relationship and identifying key driver genes for personalized cancer management. Here we performed single-cell sequencing analysis of a case of colon cancer. Population genetics analyses identified two independent clones in tumor cell population. The major tumor clone harbored APC and TP53 mutations as early oncogenic events, whereas the minor clone contained preponderant CDC27 and PABPC1 mutations. The absence of APC and TP53 mutations in the minor clone supports that these two clones were derived from two cellular origins. Examination of somatic mutation allele frequency spectra of additional 21 whole-tissue exome-sequenced cases revealed the heterogeneity of clonal origins in colon cancer. Next, we identified a mutated gene SLC12A5 that showed a high frequency of mutation at the single-cell level but exhibited low prevalence at the population level. Functional characterization of mutant SLC12A5 revealed its potential oncogenic effect in colon cancer. Our study provides the first exome-wide evidence at single-cell level supporting that colon cancer could be of a biclonal origin, and suggests that low-prevalence mutations in a cohort may also play important protumorigenic roles at the individual level. 相似文献
87.
AIMS: In this study, multidrug-resistant bacteria previously recovered from the indoor air of a large-scale swine-feeding operation were tested for the presence of five macrolide, lincosamide and streptogramin (MLS) resistance genes and five tetracycline (tet) resistance genes. METHODS AND RESULTS: Enterococcus spp. (n = 16) and Streptococcus spp. (n =16) were analysed using DNA-DNA hybridization, polymerase chain reaction (PCR) and oligoprobing of PCR products. All isolates carried multiple MLS resistance genes, while 50% of the Enterococcus spp. and 44% of the Streptococcus spp. also carried multiple tet resistance genes. All Enterococcus spp. carried erm(A) and erm(B), 69% carried erm(F), 44% carried mef(A), 75% carried tet(M), 69% carried tet(L) and 19% carried tet(K). All Streptococcus spp. carried erm(B), 94% carried erm(F), 75% carried erm(A), 38% carried mef(A), 50% carried tet(M), 81% carried tet(L) and 13% carried tet(K). CONCLUSIONS: Multidrug resistance among airborne bacteria recovered from a swine operation is encoded by multiple MLS and tet resistance genes. These are the first data regarding resistance gene carriage among airborne bacteria from swine-feeding operations. SIGNIFICANCE AND IMPACT OF THE STUDY: The high prevalence of multiple resistance genes reported here suggests that airborne Gram-positive bacteria from swine operations may be important contributors to environmental reservoirs of resistance genes. 相似文献
88.
89.
Leucaena leucocephala failed to nodulate effectively with promiscuous indigenous rhizobia with which Mucuna pruriens nodulated effectively. Mucuna pruriens was adequately established and well nodulated due to the presence of favourable climatic and edaphic factors which enhanced its establishment in the humid/moist savanna zone of Nigeria. The microsymbiont for M. pruriens seems to thrive more in an alkaline rhizosphere. Introduction of M. pruriens into the farming system in Nigeria may serve as a low input agricultural system, which is not only sustainable but also economically viable. 相似文献
90.
Robin
z Jing L Wang Raphael Guerois Gaurav Goyal Sriram KK Virginie Ropars Rajhans Sharma Firat Koca Jean-Baptiste Charbonnier Mauro Modesti Terence R Strick Fredrik Westerlund 《Nucleic acids research》2021,49(5):2629
We use single-molecule techniques to characterize the dynamics of prokaryotic DNA repair by non-homologous end-joining (NHEJ), a system comprised only of the dimeric Ku and Ligase D (LigD). The Ku homodimer alone forms a ∼2 s synapsis between blunt DNA ends that is increased to ∼18 s upon addition of LigD, in a manner dependent on the C-terminal arms of Ku. The synapsis lifetime increases drastically for 4 nt complementary DNA overhangs, independently of the C-terminal arms of Ku. These observations are in contrast to human Ku, which is unable to bridge either of the two DNA substrates. We also demonstrate that bacterial Ku binds the DNA ends in a cooperative manner for synapsis initiation and remains stably bound at DNA junctions for several hours after ligation is completed, indicating that a system for removal of the proteins is active in vivo. Together these experiments shed light on the dynamics of bacterial NHEJ in DNA end recognition and processing. We speculate on the evolutionary similarities between bacterial and eukaryotic NHEJ and discuss how an increased understanding of bacterial NHEJ can open the door for future antibiotic therapies targeting this mechanism. 相似文献