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61.
62.
Six fertilizer trials on calcareous soils in Saudi Arabia were conducted for the prediction of Zn deficiency in soybean (Glycine max L., var Merr). Zinc level before planting was tested by using 3 different extractants, i.e. DTPA, AB-DTPA and EDTA. Zinc was applied in the form of ZnSO4 · 7H2O at 0, 5, 10, 15, 20 and 40 kg Zn ha?1. Plant samples were taken at early bloom and tissue was analysed for Zn. Two methods were used to judge the critical deficiency level of Zn: Cate-Nelson and chisquare models. The critical level estimated according to the Cate-Nelson method for DTPA extractable soil Zn was 0.43 mg kg?1 in the growing season 1991. EDTA gave a much higher level (1.80 mg kg?1) and AB-DTPA gave an intermediate level (0.68 mg kg?1). Chi-square statistical procedure gave a very similar critical level of 0.66 mg kg?1 for AB-DTPA but lower for either DTPA (0.38 mg kg?1) or EDTA (1.32 mg kg?1). The critical level based for three growing seasons ranged from 0.25 to 0.68, 0.32 to 0.82 and 1.12 to 3.4 mg Zn kg?1 for DTPA, AB-DTPA and EDTA extractants, respectively. The values obtained by the linear regression equation with soybean leaf concentration were 0.45 and 0.70 mg Zn kg?1 for DTPA and AB-DTPA, respectively. Such values are very close to those determined by using the Cate-Nelson method. On the other hand, the value obtained for EDTA (1.15 mg Zn kg?1) was comparatively lower than that calculated by applying the Cate-Nelson method. 相似文献
63.
Vipra Kundoor Xiaoying Zhang Sherief Khalifa Hesham Fahmy Chandradhar Dwivedi 《Marine drugs》2006,4(4):274-285
Sarcophine derivatives have been suggested to be chemopreventive in nature. One of its derivatives, Sarcotriol (ST), was investigated to study the skin cancer chemopreventive effects in female CD-1 mice. Three groups (control, promotion, initiation) of 30 female CD-1 mice each were taken. Carcinogenesis was initiated with 7, 12- dimethylbenz (a) anthracene (DMBA) and promoted with 12-O-tetradecanoylphorbol-13- acetate (TPA). One hour before treating with DMBA (200 nmol/100 μl acetone), control and promotion groups were treated with acetone (100 μl) and initiation group with ST (30μg/100μl of acetone). Beginning one week after initiation with DMBA, control and initiation groups were treated with acetone and promotion group with ST (30μg/100μl of acetone), one hour before treating with TPA (5 nmol/100 μl acetone). This was carried out twice a week for the next 20 weeks. The effects of ST on 3H-thymidine incorporation in epidermal DNA, the possible role of apoptotic proteins and COX-2 involved in the prevention of skin tumor development of CD-1 mice were investigated. Tumor incidence and multiplicity was found to be 100%, 73%, 100% and 8.2, 4.8, 9.7 in control, promotion and initiation groups respectively. ST treatment resulted in a significant (P < 0.05) inhibition in the incorporation of 3H-thymidine in epidermal DNA. The promotion group showed higher levels of caspase-3, -8 and –9 compared to the control. COX-2 expression was significantly lower (P < 0.05) in the promotion group as compared to the control. No significant difference in caspase-3, -8, -9 and COX-2 levels were observed in the initiation group compared to control. Together, this study confirms the chemopreventive effects of ST, and for the first time identifies the stage of carcinogenesis at which ST exerts its chemopreventive effect, and elucidates the mechanism possibly by inducing apoptosis and decreasing the COX-2 levels, contributing to its overall cancer chemopreventive effects in the mouse skin cancer model. 相似文献
64.
Mahmoud A. A. Ibrahim Alaa H. M. Abdelrahman Mohamed A. M. Atia Tarik A. Mohamed Mahmoud F. Moustafa Abdulrahim R. Hakami Shaden A. M. Khalifa Fahad A. Alhumaydhi Faris Alrumaihi Syed Hani Abidi Khaled S. Allemailem Thomas Efferth Mahmoud E. Soliman Paul W. Par Hesham R. El-Seedi Mohamed-Elamir F. Hegazy 《Marine drugs》2021,19(7)
65.
66.
Genetic diversity and differentiation of Nile tilapia (Oreochromis niloticus) revealed by DNA microsatellites 总被引:2,自引:0,他引:2
To assess the genetic diversity of Nile tilapia Oreochromis niloticus, a total of 250 fish from five Egyptian populations were genotyped using six microsatellite markers. Heterozygosity and Wright's F‐statistics (FIS, FST, and FIT) were calculated to determine the genetic variation within and between these populations. Observed heterozygosities were in the range of 0.4 (Burullus) to 0.96 (Qena), with FIS values ranging from 0.082 to 0.282. The mean FST showed that approximately 96.5% of the genetic variation was within‐population and 3.5% was among populations. Standard genetic distances were used to classify the five populations into two major groups. The deeper lotic river Nile populations of Assuit and Cairo formed one group and the shallow less lotic Delta lakes populations of Manzalla and Burullus formed the second group, with the upstream Nile Qena population being an outgroup. The findings from the current study help understanding of the broad‐scale population structuring of the Nile tilapia (O. niloticus) allowing the population groupings identified to act as potential sources of genetic variation. These populations could be included in future Marker‐Assisted‐Selection programs for economically desired production traits. 相似文献
67.
M Ben Abdallah J A Marchello H A Ahmad 《Journal of agricultural and food chemistry》1999,47(10):4093-4099
The effect of freezing and bacterial growth on the discoloration of beef was assessed by measuring myoglobin derivatives myoglobin (MB), oxymyoglobin (MBO(2)), and metmyoglobin (METMB) on the surfaces of fresh and frozen-thawed packaged beef cuts stored at 2 degrees C and analyzed after 0, 3, 6, 9, and 12 days of storage. MB, MBO(2), and METMB concentrations were measured spectrophotometrically. Frozen-thawed beef samples experienced less "blooming" (conversion of MB to MBO(2)) and more rapid discoloration than fresh cuts during storage. By day 3, >20% METMB was formed in the frozen-thawed samples, whereas the fresh samples reached this value after day 6 of storage. The rates of MB oxidation were similar (P > 0.05) for sterile and frozen-thawed inoculated (Pseudomonas fluorescens at a rate of 1.5 colony forming units/cm(2).cm(2) area) samples from day 0 through day 6 of storage. For storage periods of less than a week, bacterial growth is not a major cause of meat discoloration. After day 6, the high bacterial growth rate resulted in a rapid increase in METMB formation. Possible mechanisms for MB oxidation in frozen-thawed beef are suggested. 相似文献
68.
Saccharomyces cerevisiae var. boulardii preserves the integrity of intestinal mucosa in gilthead seabream,Sparus aurata subjected to a bacterial challenge with Vibrio anguillarum 下载免费PDF全文
69.
Transient regenerative potential of the neonatal mouse heart 总被引:2,自引:0,他引:2
Porrello ER Mahmoud AI Simpson E Hill JA Richardson JA Olson EN Sadek HA 《Science (New York, N.Y.)》2011,331(6020):1078-1080
Certain fish and amphibians retain a robust capacity for cardiac regeneration throughout life, but the same is not true of the adult mammalian heart. Whether the capacity for cardiac regeneration is absent in mammals or whether it exists and is switched off early after birth has been unclear. We found that the hearts of 1-day-old neonatal mice can regenerate after partial surgical resection, but this capacity is lost by 7 days of age. This regenerative response in 1-day-old mice was characterized by cardiomyocyte proliferation with minimal hypertrophy or fibrosis, thereby distinguishing it from repair processes. Genetic fate mapping indicated that the majority of cardiomyocytes within the regenerated tissue originated from preexisting cardiomyocytes. Echocardiography performed 2 months after surgery revealed that the regenerated ventricular apex had normal systolic function. Thus, for a brief period after birth, the mammalian heart appears to have the capacity to regenerate. 相似文献