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11.
Abdurakhmonov IY Abdullaev AA Saha S Buriev ZT Arslanov D Kuryazov Z Mavlonov GT Rizaeva SM Reddy UK Jenkins JN Abdullaev A Abdukarimov A 《The Journal of heredity》2005,96(6):644-653
Cotton (Gossypium hirsutum L.) leaf defoliation has a significant ecological and economical impact on cotton production. Thus the utilization of a natural leaf defoliation trait, which exists in wild diploid cotton species, in the development of tetraploid cultivated cotton will not only be cost effective, but will also facilitate production of very high-grade fiber. The primary goal of our research was to tag loci associated with natural leaf defoliation using microsatellite markers in Upland cotton. The F2 populations developed from reciprocal crosses between the two parental cotton lines--AN-Boyovut-2 (2n = 52), a late leaf defoliating type, and Listopad Beliy (2n = 52), a naturally early leaf defoliating type--demonstrated that the naturally early leaf defoliation trait has heritability values of 0.74 and 0.84 in the reciprocal F2 population. The observed phenotypic segregation difference in reciprocal crosses suggested a minor cytoplasmic effect in the phenotypic expression of the naturally early leaf defoliation trait. Results from the Kruskal-Wallis (KW) nonparametric test revealed that JESPR-13 (KW = 6.17), JESPR-153 (KW = 9.97), and JESPR-178 (KW = 13.45) Simple sequence repeat (SSR) markers are significantly associated with natural leaf defoliation in the mapping population having stable estimates at empirically obtained critical thresholds (P < .05-.0001). JESPR-178 revealed the highest estimates (P < .0001) for association with the natural leaf defoliation trait, exceeding maximum empirical threshold values. JESPR-178 was assigned to the short arm of chromosome 18, suggesting indirectly that genes associated with natural leaf defoliation might be located on this chromosome. This microsatellite marker may have the potential for use to introgress the naturally early leaf defoliation quantitative trait loci (QTL) from the donor line Listopad Beliy to commercial varieties of cotton through marker-assisted selection programs. 相似文献
12.
Monitoring on the Lowveld reaches of the Olifants River, Limpopo River System, and its Steelpoort, Blyde, Klaserie and Selati tributaries was initiated in 2009. Analysis of the 2009–2015 data from four Olifants River sites showed deterioration in the river’s ecological condition between where it enters the Lowveld and where it enters the Kruger National Park, with a slight recovery within the Kruger National Park. Physico-chemical, aquatic macroinvertebrate and fish data collected in 2009–2015 at six sites on the Steelpoort, Blyde, Klaserie and Selati tributaries of the Olifants River corroborated the ecological condition of these tributaries. The Selati was the most polluted and was in a critically modified condition, whereas the Klaserie and Steelpoort were in fair condition and the Blyde was in good condition. The Selati appeared to have a significant negative impact on the water quality, macroinvertebrates and fish of the Olifants River within the Kruger National Park. 相似文献
13.
Homogenization of geographical variants at the nontranscribed spacer of rDNA in Drosophila mercatorum 总被引:2,自引:0,他引:2
rDNA nontranscribed spacer (NTS) lengths of Drosophila mercatorum have been
measured in individuals from several geographic regions. Individuals from
the different geographic subpopulations share some length fragments but are
in general distinct. The length differences, both within and between
individuals, arise from different copy numbers of a 250-bp repeating unit
that is localized to one part of the NTS. In addition to the length
differences caused by the 250-bp repeat, there is a Y chromosome
(male)-specific length variant elsewhere in the NTS that is approximately
70 bp shorter than the NTS fragment from the X chromosome. Sexual
dimorphism seems to be present in all Drosophila. Also, D. mercatorum has
fewer NTS length variants per individual than does D. melanogaster while
possessing comparable levels of restriction- site polymorphism. The
mechanisms that may cause this pattern of variation are selection, gene
conversion, and unequal recombination.
相似文献
14.
The influence of optimization target selection on the structure of arterial tree models generated by constrained constructive optimization 总被引:1,自引:1,他引:0
W Schreiner F Neumann M Neumann A End SM Roedler S Aharinejad 《The Journal of general physiology》1995,106(4):583-599
The computational method of constrained constructive optimization was used to generate complex arterial model trees by optimization with respect to a target function. Changing the target function also changes the tree structure obtained. For a parameterized family of target functions a series of trees was created, showing visually striking differences in structure that can also be quantified by appropriately chosen numerical indexes. Blood transport path length, pressure profile, and an index for relative segment orientation show clear dependencies on the optimization target, and the nature of changes can be explained on theoretical grounds. The main goal was to display, quantify, and explain the structural changes induced by different optimization target functions. 相似文献
15.
Quantitative analysis of organophosphorus pesticides in freshwater using an optimized firefly luciferase‐based coupled bioluminescent assay 下载免费PDF全文
In this paper, a coupled bioluminescent assay, relying on the coupling of the enzymes acetylcholinesterase, S‐acetyl‐coenzyme A synthetase and firefly luciferase, for the detection and quantitation of organophosphorus pesticides, is presented. Using malathion as a model organophosphorus pesticide, the assay was optimized through statistical experimental design methodology, namely Plackett–Burman and central composite designs. The optimized method requires only 20 μL of sample. The linear range for the assay was 2.5–15 μM of malathion, with limits of detection and quantitation of 1.5 and 5.0 μM, respectively. This simple, fast and robust method allows samples to be analyzed at room temperature and without any pretreatment. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
16.
Aldair JW Pinto Maria M Figueiredo Fabiana L Silva Trycia Martins Marilene SM Michalick Washington L Tafuri Wagner L Tafuri 《Acta veterinaria Scandinavica》2011,53(1):1-8
Background
A nationwide survey on the microbial etiology of cases of subclinical mastitis in dairy cows was carried out on dairy farms in Sweden. The aim was to investigate the microbial panorama and the occurrence of antimicrobial resistance. Moreover, differences between newly infected cows and chronically infected cows were investigated.Methods
In total, 583 quarter milk samples were collected from 583 dairy cows at 226 dairy farms from February 2008 to February 2009. The quarter milk samples were bacteriological investigated and scored using the California Mastitis Test. Staphylococci were tested for betalactamase production and presence of resistance was evaluated in all specific udder pathogens. Differences between newly infected cows and chronically infected cows were statistically investigated using logistic regression analysis.Results
The most common isolates of 590 bacteriological diagnoses were Staphylococcus (S) aureus (19%) and coagulase-negative staphylococci (CNS; 16%) followed by Streptococcus (Str) dysgalactiae (9%), Str. uberis (8%), Escherichia (E.) coli (2.9%), and Streptococcus spp. (1.9%). Samples with no growth or contamination constituted 22% and 18% of the diagnoses, respectively. The distribution of the most commonly isolated bacteria considering only bacteriological positive samples were: S. aureus - 31%, CNS - 27%, Str. dysgalactiae - 15%, Str. uberis - 14%, E. coli - 4.8%, and Streptococcus spp. - 3.1%. There was an increased risk of finding S. aureus, Str. uberis or Str. dysgalactiae in milk samples from chronically infected cows compared to findings in milk samples from newly infected cows. Four percent of the S. aureus isolates and 35% of the CNS isolates were resistant to penicillin G. Overall, resistance to other antimicrobials than penicillin G was uncommon.Conclusions
Staphylococcus aureus and CNS were the most frequently isolated pathogens and resistance to antimicrobials was rare. 相似文献17.
Metal concentrations in the gill, muscle and liver tissues of Labeo rosae from two impoundments, Loskop and Flag Boshielo dams on the Olifants River, were evaluated in 2011 to detect patterns in metal associations between tissues and impoundments. Elevated concentrations of Ba, Zn, B, Al, Si and Fe, relative to a pristine site in the catchment, were found in the muscle, liver and gill tissues at both impoundments. Molybdenum concentrations were exceptionally high in all tissues at Loskop Dam and in liver at Flag Boshielo Dam. No definite pattern in the ratio metal concentrations within, or between, fish tissues was identified. The expected trend, liver > gills > muscle, was found at both impoundments, but was less prominent at Loskop Dam. Metal concentrations in muscle of Loskop Dam fish were significantly higher than in those at Flag Boshielo Dam. The inverse was true for liver. The long-term impact of elevated metal concentrations on fish health at both impoundments raises concern. 相似文献
18.
Muhammad Toyabur Rahman SM Sohel Rana Md Salauddin Pukar Maharjan Trilochan Bhatta Jae Yeong Park 《Liver Transplantation》2020,10(12)
The fast growth of smart electronics requires novel solutions to power them sustainably. Portable power sources capable of harvesting biomechanical energy are a promising modern approach to reduce battery dependency. Herein, a novel elastic impact‐based nonresonant hybridized generator (EINR‐HG) is reported to effectively harvest biomechanical energy from diverse human activities outdoors. Through the rational integration of a nonlinear electromagnetic generator with two contact‐mode triboelectric nanogenerators, the proposed EINR‐HG generates hybrid electrical output simultaneously under the same mechanical excitations. By introducing a flux‐concentrator with a nanowire‐nanofiber surface modification, significant improvement in the energy harvesting efficiency of the EINR‐HG is achieved. After optimizing using simulations and vibration tests, the as‐fabricated EINR‐HG delivers an outstanding normalized power density of 3.13 mW cm?3 g?2 across a matching resistance of 1.5 kΩ at 6 Hz under 1 g acceleration. Under human motion testing, the EINR‐HG generates an optimal output power of 131.4 mW with horizontal handshaking. With a customized power management circuit, the EINR‐HG serves as a universal power source that successfully drives commercial smart electronics, including smart bands and smartphones. This work shows the massive potential of biomechanical energy‐driven hybridized generators for powering personal electronics and portable healthcare monitoring devices. 相似文献
19.
Lipase biosynthesis by the fungus Rhizopus microsporus UzLT-1 was investigated. Under certain conditions the fungus could produce two forms of extracellular lipases. The paper describes the process of purification of the enzyme L-I,N- and C-terminal amino acids of the lipases have been determined. Identity of terminal amino acids of both enzymes has been demonstrated. It has been shown that both forms of lipase from Rhizopus microporus hydrolyze predominantly alpha-ester bonds. 相似文献
20.