Highlights • Ascl1 induces neurons at high efficiency in the embryonic, postnatal and juvenile mouse cochlea. • Ascl1-induced neurons express several neuronal markers including synaptic proteins. • ...Ascl1-induced neurons are functional generating action potentials.
Forty-eight wing vein blood samples were collected from different locations of poultry rearing farms and back yard chickens of Nineveh governorate from the of local and exotic chicken. The chicken ...divided into twelve groups four birds each according to colors and phenotype for the local and exotic chicken respectively. Blood DNA was extracted and amplified by thermocycler apparatus and the electrophoresis was done using 1.2% agarose gel for DNA bands exhibiting. The results showed high genetic similarity within the local chickens ranged between 0.78- 0.96 at an average of 0.88, while it ranged between 0.73- 0.86 at an average of 0.78 in exotic breeds. The degree of similarity between Iraqi and exotic breeds was 0.74-0.88 at average of 0.80. The calculated average of differences among each of Iraqi and exotic chickens and in between were 0.12, 0.22 and 0.20, respectively. However, the genetic distance within the local chicken, exotic breed and in between them was 0.128, 0.24 and 0.21 respectively. The study concluded that the genetic similarity was higher within local chicken groups than those of exotic breeds.
Incomplete retinal vascularization occurs in both Norrie disease and familial exudative vitreoretinopathy (FEVR). Norrin, the protein product of the Norrie disease gene, is a secreted protein of ...unknown biochemical function. One form of FEVR is caused by defects in Frizzled-4 (Fz4), a presumptive Wnt receptor. We show here that Norrin and Fz4 function as a ligand-receptor pair based on (1) the similarity in vascular phenotypes caused by Norrin and Fz4 mutations in humans and mice, (2) the specificity and high affinity of Norrin-Fz4 binding, (3) the high efficiency with which Norrin induces Fz4- and Lrp-dependent activation of the classical Wnt pathway, and (4) the signaling defects displayed by disease-associated variants of Norrin and Fz4. These data define a Norrin-Fz4 signaling system that plays a central role in vascular development in the eye and ear, and they indicate that ligands unrelated to Wnts can act through Fz receptors.
The basic helix-loop-helix (bHLH) transcription factor Math1 (also called Atoh1) is both necessary and sufficient for hair cell development in the mammalian cochlea (Bermingham et al., 1999; Zheng ...and Gao, 2000). Previous studies have demonstrated that a dynamic pattern of Math1 expression plays a key role in regulating the number and position of mechanosensory hair cells. However, the factors that regulate the temporal and spatial expression of Math1 within the cochlea are unknown. The bHLH-related inhibitors of differentiation and DNA binding (Id) proteins are known to negatively regulate many bHLH transcription factors, including Math1, in a number of different systems. Therefore, Id proteins are good candidates for regulating Math1 in the cochlea. Results from PCR and in situ hybridization indicate that Id1, Id2, and Id3 are expressed within the cochlear duct in a pattern that is consistent with a role in regulation of hair cell development. In particular, expression of Ids and Math1 overlapped in cochlear progenitor cells before cellular differentiation, but a specific downregulation of Id expression was observed in individual cells that differentiated as hair cells. In addition, progenitor cells in which the expression of Ids was maintained during the time period for hair cell differentiation were inhibited from developing as hair cells. These results indicate a key role for Ids in the regulation of expression of Math1 and hair cell differentiation in the developing cochlea.
In the mammalian cochlea, stereociliary bundles located on mechanosensory hair cells within the sensory epithelium are unidirectionally oriented. Development of this planar polarity is necessary for ...normal hearing as stereociliary bundles are only sensitive to vibrations in a single plane; however, the mechanisms governing their orientation are unknown. We report that Wnt signaling regulates the development of unidirectional stereociliary bundle orientation. In vitro application of Wnt7a protein or inhibitors of Wnt signaling, secreted Frizzled-related protein 1 or Wnt inhibitory factor 1, disrupts bundle orientation. Moreover, Wnt7a is expressed in a pattern consistent with a role in the polarization of the developing stereociliary bundles. We propose that Wnt signaling across the region of developing outer hair cells gives rise to planar polarity in the mammalian cochlea.
3′-Azido-2′,3′-dideoxythymidine (AZT, zidovudine) is the principal antiretroviral agent in the treatment of AIDS. Although beneficial, AZT remains restricted for human usage because of its severe ...toxic effects. We examined the AZT sensitivity in transgenic mice expressing HIV-1 one-exon-encoded 72 amino acid Tat (Tat72) and full-length 86 amino acid Tat (Tat86) proteins. Administration of AZT (1 mg/ml) in drinking water for 1 week resulted in a three- to fourfold decrease in hematopoietic progenitors from bone marrow in Tat mice compared to AZT-treated nontransgenic controls as determined by erythroid and granulocyte/macrophage colony-forming unit assays. In liver and thymus, two of the tissues examined, AZT treatment of Tat mice resulted in as much as 80–90% suppression of Mn-superoxide dismutase (Mn-SOD) activity. Other parameters associated with loss of Mn-SOD such as increase in carbonyl proteins and decrease of sulfhydryl content were also significantly enhanced by AZT in Tat mice. Ourin vivostudy suggests that AZT therapy is associated with oxidative damage affecting cellular functions in several tissues and that Tat is one of the contributory factors in AZT-induced toxicities. The findings of AZT-induced oxidative damage may help to improve the therapeutic index of AZT and other related drugs in AIDS patients.
A Total of 180 day old male Cobb broiler chicks were raised, from day old untill 42 day of age to investigate the effect of adding graded levels of methionine (0.10, 0.15 and 0.20%) in comparison ...with basal diet on broiler body weight, uniformity and the relationship between economical traits and economical efficiency. The birds were equally distributed into four groups , with 45 birds each,and were allocated in three replications. Highest body weight was found in the chicks group that consumed ration consist in (0.15%)methionine at various ages.This treatment showed similar results for body weight uniformity and relative growth rate, in comparison with the other treatment groups. Feed conversion was significantly altered due to effect of methionine supplementation at (0.15 ,0.20%)levels vs first treatment. Feed intake and liveability were not affected by any level of methionine supplementation. Economical efficiency of the third group was the best when compared with others. Regression and simple correlation analyses revealed that third treatment showed that relationships among the performance traits was the best at 42 days of age.
Birth weight of 149 Friesian, 270 Sharabi and 121 crossbred calf's males and females were utilized. The mortality rates have been obtained from birth until weaning for each breed in males and ...females. Average birth weight in male's survival group for sharabi, Friesian and crossbred were 20.94, 30.82 and 30.19 kg respectively, and in females were 18.42, 29.11 and 28.10 kg, respectively. Birth weight in Sharabi was significantly different (P<0.01) from Friesian and crossbred in both males and females. In mortal group the birth weight was significantly (P<0.01) less than survival group in both sexes and for each breed. Mortality rate in males and females were (14.1%, 16.7%) in Frieasian, (21.2%, 23.6%) in Sharabi and (8.8%, 7.5%) in crossbred respectively, which differ significantly (P<0.01) among breeds. But, no significant difference between males and females was detected. The Point-Biserial correlations between mortality anb birth weight were negative and highly significant for the three breeds in males and females. The threshold point of birth weight values which gave the best efficiency, the efficiency were for Friesian (89%, 85%), Sharabi (86%, 80%) and crossbred (93%, 94%) for males and females calves respectively, Fm and Fc, as well as efficiency were determined. Advantageous results were in least specificity Fm and Fc, and in high efficiency and sensitivity. The threshold values of birth weight for classifying mortal and survival groups were (25.6, 26.6 kg) in Friesian, (16.6, 16.1 kg) in Sharabi, and (24.6, 22.6 kg) in crossbred in male and female, respectively.
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