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排序方式: 共有306条查询结果,搜索用时 31 毫秒
41.
Perveen Sumera Khan Tehmina Ahsan Shaheen Humaira Naz Rabia Hyder Muhammad Zeeshan Ijaz Bushra Naqvi S. M. Saqlan Yasmin Tayyaba 《In vitro cellular & developmental biology. Plant》2021,57(6):907-922
In Vitro Cellular & Developmental Biology - Plant - The OsRGLP1 gene was overexpressed under the control of CaMV 35S promoter in tomato (Solanum lycopersicum L.) plants using... 相似文献
42.
A study was conducted to assess the rhythmic pattern of physiological parameter in Malpura ewes to adapt to cold stress in a semi-arid tropical environment. Eighteen adult Malpura ewes were selected for the present study. These ewes were randomly allocated into two groups: GI (Open shed; n=9) and GII (Protected; n=9). The study was conducted for a period of 30 days during the peak winter season (December 2011) during which the animals were stall fed. Blood samples were collected at fortnightly interval. The growth, physiological response, blood biochemical response and endocrine response parameters were studied. The results reveal that cold stress had significant negative influence on all the parameters studied in the ewes. In conclusion, it can be said that cold stress had significant influence on the biological functions in the ewes that would result in the impairment of their production and reproductive efficiency as well. The study also indicates the relevance of provision of appropriate protective measures to foster cold during the extreme winter months in the arid and semi-arid tropical areas. 相似文献
43.
A study was conducted to assess the biological ability of Malpura rams to counter heat stress challenges and its impact on the productive performance in a semi-arid tropical environment. The eighteen adult Malpura rams (average body weight 55.0 kg) were divided into two groups, GI (n = 9; Control) and GII (n = 9; heat stress). The study was conducted for a period of 60 days. The results showed that body weight, body condition score, heart girth and feed intake were significantly (p < 0.05) lower in GII as compared to GI rams. The physiological responses i.e. respiration rate, pulse rate, rectal temperature and sweating rate (body and scrotum) were significantly (p < 0.05) higher in rams exposed to heat stress. Among the endocrine parameters, plasma T3, T4 and testosterone concentrations were significantly (p < 0.05) lower in GII rams, while cortisol concentration was significantly (p < 0.05) higher in GII rams. In addition, heat stress significantly (p < 0.05) reduced semen volume, total sperm motility, sperm concentration and progressive sperm motility in GII rams. The results indicated that Malpura rams adapted to the heat stress condition, however, while doing so their production performances were compromised. 相似文献
44.
45.
The study was conducted with the primary objective to establish the impact of simultaneously imposed multiple stressors (thermal, nutritional and walking) on various biological functions in Malpura rams. The study was conducted for a period of 45 days. Twenty adult Malpura rams (average BW 44.9 Kg) were used in the present study. The rams were divided into two groups, CON (n = 10; Control) and MS (n = 10; multiple stressors). Both body weight (p < 0.05) and body condition scoring (p < 0.01) were lower in MS compared with CON rams. All the scrotal measurements reduced significantly (p < 0.01) in MS rams. All the testicular measurements also reduced significantly (p < 0.01) in MS as compared to CON rams. The seminal attributes, individual motility (p < 0.05), rapid motility (p < 0.05) and curvilinear velocity (p < 0.05) were significantly reduced in CON rams. However, slowness (p < 0.05), linearity (p < 0.05) and straightness (p < 0.05) parameters significantly increased in MS as compared to CON rams. In addition, plasma testosterone concentration was lower (p < 0.05) in MS rams. The study established the impact of multiple stressors on growth and reproductive performance of Malpura rams. Further, the results revealed that the only semen quality was affected by multiple stressors, but the semen production remained intact between the groups, indicating the extreme adaptive capability of Malpura rams to hot semi-arid tropical environment. 相似文献
46.
Naqvi RA Hussain A Raish M Noor A Shahid M Sarin R Kukreti H Khan NJ Ahmad S Deo SV Husain SA Pasha ST Basir SF Shukla NK 《DNA and cell biology》2008,27(9):517-525
Even after tremendous molecular studies, early detection,more accurate and sensitive diagnosis, and prognosis of breast cancer appear to be a riddle so far. To stab the enigma, this study is designed to envisage DNA methylation signatures as cancer-specific and stage-specific biomarkers in Indian patients. Rigorous review of scattered scientific reports on aberrant DNA methylation helped us to select and analyze a potential tumor suppressor gene pair (FHIT and p16 genes) in breast cancer patients. Methylation signatures from 232 primary sporadic breast cancer patients were pinpointed by methylation-specific PCR (MSP). To increase the sensitivity, we combined both MSP and expression studies (RT-PCR and Northern blotting) in a reproducible manner. Statistical analysis illustrated that hypermethylation of FHIT gene ( p < 0.0001) and p16 gene ( p=0.04) may be used as a potential diagnostic marker to diagnose the early and locally advanced stages of breast cancer. Additionally, the study authenticates the dependency of methylation and expressional loss of p16 gene on FHIT gene silencing. This observation not only describes the severity of disease when both genes are silenced but also drives to speculate the molecular cross talk between two genes or genetic pathways dictated by them separately. 相似文献
47.
A microdiversity study of anammox bacteria reveals a novel Candidatus Scalindua phylotype in marine oxygen minimum zones 总被引:4,自引:0,他引:4
Woebken D Lam P Kuypers MM Naqvi SW Kartal B Strous M Jetten MS Fuchs BM Amann R 《Environmental microbiology》2008,10(11):3106-3119
The anaerobic oxidation of ammonium (anammox) contributes significantly to the global loss of fixed nitrogen and is carried out by a deep branching monophyletic group of bacteria within the phylum Planctomycetes. Various studies have implicated anammox to be the most important process responsible for the nitrogen loss in the marine oxygen minimum zones (OMZs) with a low diversity of marine anammox bacteria. This comprehensive study investigated the anammox bacteria in the suboxic zone of the Black Sea and in three major OMZs (off Namibia, Peru and in the Arabian Sea). The diversity and population composition of anammox bacteria were investigated by both, the 16S rRNA gene sequences and the 16S-23S rRNA internal transcribed spacer (ITS). Our results showed that the anammox bacterial sequences of the investigated samples were all closely related to the Candidatus Scalindua genus. However, a greater microdiversity of marine anammox bacteria than previously assumed was observed. Both phylogenetic markers supported the classification of all sequences in two distinct anammox bacterial phylotypes: Candidatus Scalindua clades 1 and 2. Scalindua 1 could be further divided into four distinct clusters, all comprised of sequences from either the Namibian or the Peruvian OMZ. Scalindua 2 consisted of sequences from the Arabian Sea and the Peruvian OMZ and included one previously published 16S rRNA gene sequence from Lake Tanganyika and one from South China Sea sediment (97.9-99.4% sequence identity). This cluster showed only 相似文献
48.
Venigalla Purnachandra Rao Ernst Hegner Syed Wajih Ahmad Naqvi Pratima Mohan Kessarkar Syed Masood Ahmad Datta Suryanarayana Raju 《Palaeogeography, Palaeoclimatology, Palaeoecology》2008,260(3-4):347-358
Phosphorites from the Murray Ridge, NW Arabian Sea comprise nodules, bioclasts, and bone fragments. The nodules are made up of a homogeneous, light-colored phosphate nucleus consisting of Rivulariacean filamentous cyanobacteria and a thin dark-grey colored phosphate cortex showing abundant microbial filaments and microborings. The bioclasts comprise of 14–14.5 Ma old planktonic foraminifers, accepted as the time of deposition. Spherical to ovoid-shaped apatite microparticles resembling fossil bacteria are distinct components in the bioclasts. Bone fragments exhibit apatite fillings. The nodules and bone fragments consist entirely of carbonate fluorapatite (CFA) with low Al, K, and Th concentrations suggesting absence of continental detritus. Shale-normalized REE patterns of the samples support a seawater-derived composition. The highly uniform initial Nd values of − 4.8 to − 5.1 are interpreted as the seawater value at the onset of phosphatization 14 Ma ago. In contrast, 87Sr/86Sr ratios show a large range of 0.709055 to 0.709124 corresponding to unusually young stratigraphic ages of 1 to 3 Ma. The data are interpreted as evidence for post-depositional Sr exchange of the recrystallizing phosphorites with fluids isotopically not much different from modern seawater. It is concluded that the phosphorites formed under oxic, shallow-water conditions where microbial populations assimilated phosphorus primarily from seawater and mediated precipitation of CFA during early diagenesis at the sediment–water interface on different substrates. 相似文献
49.
Denitrification in the ocean is a major sink for fixed nitrogen in the global N budget, but the process is geographically
restricted to a few oceanic regions, including three oceanic oxygen minimum zones (OMZ) and hemipelagic sediments worldwide.
Here, we describe the diversity and community composition of microbes responsible for denitrification in the OMZ using polymerase
chain reaction, sequence and fragment analysis of clone libraries of the signature genes (nirK and nirS) that encode the enzyme nitrite reductase, responsible for key denitrification transformation steps. We show that denitrifying
assemblages vary in space and time and exhibit striking changes in diversity associated with the progression of denitrification
from initial anoxia through nitrate depletion. The initial denitrifying assemblage is highly diverse, but succession on the
scale of 3–12 days leads to a much less diverse assemblage and dominance by one or a few phylotypes. This progression occurs
in the natural environment as well as in enclosed incubations. The emergence of dominants from a vast reservoir of rare types
has implications for the maintenance of diversity of the microbial population and suggests that a small number of microbial
dominants may be responsible for the greatest rates of transformations involving nitrous oxide and global fixed nitrogen loss.
Denitrifying blooms, driven by a few types responding to episodic environmental changes and distributed unevenly in time and
space, are consistent with the sampling effect model of diversity–function relationships. Canonical denitrification thus appears
to have important parallels with both primary production and nitrogen fixation, which are typically dominated by regionally
and temporally restricted blooms that account for a disproportionate share of these processes worldwide. 相似文献
50.
Ketocarotenoids such as astaxanthin and canthaxanthin have important applications in the nutraceutical, cosmetic, food and feed industries. Astaxanthin is derived from β-carotene by 3-hydroxylation and 4-ketolation at both ionone end groups. These reactions are catalyzed by β-carotene hydroxylase and β-carotene ketolase, respectively. The hydroxylation reaction is widespread in higher plants, but ketolation is restricted to a few bacteria, fungi, and some unicellular green algae. The recent cloning and characterization of β-carotene ketolase genes in conjunction with the development of effective co-transformation strategies permitting facile co-integration of multiple transgenes in target plants provided essential resources and tools to produce ketocarotenoids in planta by genetic engineering. In this review, we discuss ketocarotenoid biosynthesis in general, and characteristics and functional properties of β-carotene ketolases in particular. We also describe examples of ketocarotenoid engineering in plants and we conclude by discussing strategies to efficiently convert β-carotene to astaxanthin in transgenic plants. 相似文献