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11.
Mouse genetics has made crucial contributions to the understanding of the molecular mechanisms of hearing. With the help of a plethora of mouse mutants, many of the key genes that are involved in the development and functioning of the auditory system have been elucidated. Mouse mutants continue to shed light on the genetic and physiological bases of human hearing impairment, including both early- and late-onset deafness. A combination of genetic and physiological studies of mouse mutant lines, allied to investigations into the protein networks of the stereocilia bundle in the inner ear, are identifying key complexes that are crucial for auditory function and for providing profound insights into the underlying causes of hearing loss. 相似文献
12.
Jamie L Hass Erin M Garrison Sarah A Wicher Ben Knapp Nathan Bridges DN Mcllroy Gustavo Arrizabalaga 《Journal of nanobiotechnology》2012,10(1):1-12
Background
Angiogenesis is widely investigated in conjunction with cancer development, in particular because of the possibility of early stage detection and of new therapeutic strategies. However, such studies are negatively affected by the limitations of imaging techniques in the detection of microscopic blood vessels (diameter 3-5 ??m) grown under angiogenic stress. We report that synchrotron-based X-ray imaging techniques with very high spatial resolution can overcome this obstacle, provided that suitable contrast agents are used.Results
We tested different contrast agents based on gold nanoparticles (AuNPs) for the detection of cancer-related angiogenesis by synchrotron microradiology, microtomography and high resolution X-ray microscopy. Among them only bare-AuNPs in conjunction with heparin injection provided sufficient contrast to allow in vivo detection of small capillary species (the smallest measured lumen diameters were 3-5 ??m). The detected vessel density was 3-7 times higher than with other nanoparticles. We also found that bare-AuNPs with heparin allows detecting symptoms of local extravascular nanoparticle diffusion in tumor areas where capillary leakage appeared.Conclusions
Although high-Z AuNPs are natural candidates as radiology contrast agents, their success is not guaranteed, in particular when targeting very small blood vessels in tumor-related angiography. We found that AuNPs injected with heparin produced the contrast level needed to reveal--for the first time by X-ray imaging--tumor microvessels with 3-5 ??m diameter as well as extravascular diffusion due to basal membrane defenestration. These results open the interesting possibility of functional imaging of the tumor microvasculature, of its development and organization, as well as of the effects of anti-angiogenic drugs. 相似文献13.
Katie J Torley Juliano C da Silveira Peter Smith Russell V Anthony DN Rao Veeramachaneni Quinton A Winger Gerrit J Bouma 《Reproductive biology and endocrinology : RB&E》2011,9(1):2
Background
Gonadal differentiation in the mammalian fetus involves a complex dose-dependent genetic network. Initiation and progression of fetal ovarian and testicular pathways are accompanied by dynamic expression patterns of thousands of genes. We postulate these expression patterns are regulated by small non-coding RNAs called microRNAs (miRNAs). The aim of this study was to identify the expression of miRNAs in mammalian fetal gonads using sheep as a model. 相似文献14.
P. K. Sirmah F. G. Mburu F. N. Muisu G. M. Wahungu C. W. Waweru 《African Journal of Ecology》2009,47(4):693-698
The activity of marine borers was investigated at Mtongwe Jetty Pontoon, Mombasa, Kilindini harbour using untreated panels of Pinus patula (Schlecht) submerged to different depths. Twenty test panels replicated over 7 months were each strung in three ladder‐like frames using nylon twine and suspended vertically, in such a way that the top most panels were 25 cm below the water surface at low and high tide. Monthly observations were made between January and July for the vertical incidence and extent of marine borer attack following the technique of Bobat (1995) . Marine borers were collected from test panels, identified and counted. In addition, the percentage weight loss for panels at different depths was determined at the end of 7 months. Teredo fulleri (Clapp) was dominant on panels near water surface while Martesia striata (Linne) and Lyrodus pedicellatus (Quatrefages) were predominant at the bottom. The results showed that attack began within the first month of exposure and was severest by the seventh month. The vertical incidence and extent of attack decreased with increasing depth of panel exposure and was negatively correlated with depth. This is attributed to changes in hydrographic conditions. 相似文献
15.
Termites encounter a diverse array of potentially useful and harmful fungi in their subterranean habitats. These vary from symbiotic to harmful species with varying levels of virulence. How these hemiedaphic insects survive in habitats with infective fungi is not well understood. Possible mediation of olfactory signals in avoiding contact with entomopathogenic fungi has been explored by a number of workers. In the present study, we initially found that Macrotermes michaelseni detected a virulent isolate of Metarhizium anisopliae from some distance and avoided direct physical contact. We hypothesized that there may be a relationship between virulence and repellency of different isolates of M. anisopliae and Beauveria bassiana to the termite. We compared these for selected isolates of the two fungi. Positive correlations between the two parameters for both sets of isolates of the fungi were obtained. The results show an interesting co-evolutionary phenomenon in which the termite's response to either M. anisopliae or B. bassiana is directly related to potential harm these fungi can inflict on the insect and that the virulent strains are more likely to be recognized from some distance and avoided. 相似文献
16.
Protective effect of whey protein hydrolysates against hydrogen peroxide-induced oxidative stress on PC12 cells 总被引:1,自引:0,他引:1
Qiu-Xiang Zhang Yu-Fang Ling Zhen Sun Li Zhang Hui-Xin Yu Samuel Mburu Kamau Rong-Rong Lu 《Biotechnology letters》2012,34(11):2001-2006
The protective effect of whey protein hydrolysates (WPHs) against H2O2-induced oxidative damage on rat pheochromocytoma line 12 (PC12) cells was studied. Whey protein was hydrolyzed by pepsin and trypsin and purified by macrospore absorption resins. PC12 cells were pretreated with WPHs (from 369 to 1,980?Da) at different concentrations for 2?h, then washed and incubated with 100?μM H2O2 in the presence of WPHs for another 24?h. With 100–400?μg WPH/ml the viable cells increased by 20–30?% when incubated with H2O2 suggesting that they may play a role as antioxidant in foods. 相似文献
17.
V. W. Wasike D. Lesueur F. N. Wachira N. W. Mungai L. M. Mumera N. Sanginga H. N. Mburu D. Mugadi P. Wango B. Vanlauwe 《Plant and Soil》2009,322(1-2):151-163
While soybean is an exotic crop introduced in Kenya early last century, promiscuous (TGx) varieties which nodulate with indigenous rhizobia have only recently been introduced. Since farmers in Kenya generally cannot afford or access fertilizer or inoculants, the identification of effective indigenous Bradyrhizobium strains which nodulate promiscuous soybean could be useful in the development of inoculant strains. Genetic diversity and phylogeny of indigenous Bradyrhizobium strains nodulating seven introduced promiscuous soybean varieties grown in two different sites in Kenya was assayed using the Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) of the 16S-23S rDNA intergenic spacer region and 16S rRNA gene sequencing. PCR-RFLP analysis directly applied on 289 nodules using Msp I distinguished 18 intergenic spacer groups (IGS) I–XVIII. Predominant IGS groups were I, III, II, IV and VI which constituted 43.9%, 24.6%, 8.3% 7.6% and 6.9% respectively of all the analyzed nodules from the two sites while IGS group VII, IX, X, XI, XII, XIV, XVI, XVII, XVIII each constituted 1% or less. The IGS groups were specific to sites and treatments but not varieties. Phylogenetic analysis of the 16S rRNA gene sequences showed that all indigenous strains belong to the genus Bradyrhizobium. Bradyrhizobium elkanii, Bradyrhizobium spp and Bradyrhizobium japonicum related strains were the most predominant and accounted for 37.9%, 34.5%, and 20.7% respectively while B. yuanmigense related accounted for 6.9% of all strains identified in the two combined sites. The diversity identified in Bradyrhizobium populations in the two sites represent a valuable genetic resource that has potential utility for the selection of more competitive and effective strains to improve biological nitrogen fixation and thus increase soybean yields at low cost. 相似文献
18.
DN Akongyuure S Amisah TK Agyemang RE Edziyie 《African Journal of Aquatic Science》2017,42(2):143-154
Fishery characteristics and livelihood status of fishers at Tono Reservoir, Ghana, were investigated between January 2015 and June 2016. Data on fisher demography, fishing gears, fishing methods, perceptions of the state of fish stocks, management practices, income and consumption of fishers were obtained through structured interviews. Censuses of fishers and fishing gears were conducted through direct observation and counts. The population of fishers was 950 and the majority (74%) of the sampled respondents fell within the ages of 24–41 years. Gillnet, cast net, trap and hook and line were the four main gears utilised. Illegal methods of fishing observed included the use of mosquito nets (nets with mesh <1.0 cm) and the use of brewer’s waste (pito mash) as bait. Brycinus nurse, Synodontis spp., Parailia spiniserrata and Chrysichthys spp. were perceived to have disappeared from the reservoir. The fishers were unaware of the existence of any fisheries regulations, hence there was no adherence to management practices. Their daily income was derived mainly from fishing. The incidence of poverty among fishers was low (8%). The Tono Reservoir has a great potential for supporting livelihood if it is properly managed. 相似文献
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20.
Michael J.C. Rogers Jane Fleming Brent W. Kiernan Philomena Mburu Anabel Varela Steve D.M. Brown Karen P. Steel 《Mammalian genome》1999,10(5):513-519
The whirler (wi) mutation on mouse Chromosome (Chr) 4 results in an autosomal recessive neuroepithelial deafness and vestibular dysfunction
exhibited as a characteristic shaker-waltzer behavior (deafness, circling, and head-bobbing). We have constructed a genetic
linkage map across the wi region in both an interspecific [(wi/wi× CAST/Ei)F1×wi/wi] backcross (n = 817) and an intraspecific [(wi/wi× CBA/Ca)F1×wi/wi)] backcross (n = 335). In the interspecific backcross, wi was found to be non-recombinant with Orm1, 0.12 cM distal of D4Mit87 and Ambp, and 0.12 cM proximal of CD301. In the intraspecific backcross, wi was found to be non-recombinant with Orm1 and D4Mit244, 0.3 cM distal of Mup1, and 0.6 cM proximal of Tnc. We also report a family from the interspecific backcross that shows evidence of multiple recombinations across the region
of mouse Chr 4 around the wi locus. These rearrangements appear specific to both the region and the family.
Received: 10 July 1998 / Accepted: 19 January 1999 相似文献