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31.
32.
Hao Bing Li Guo Qiang Xie Jun Ma Gui Ru Liu Shu Min Wen Tomohiro Ban Sukumar Chakraborty Chun Ji Liu 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2010,121(5):941-950
Fusarium head blight (FHB) and crown rot (CR) are two wheat diseases caused by the same Fusarium pathogens. Progress towards CR resistance could benefit from FHB-resistant germplasm if the same genes are involved in resistance
to these two different diseases. Two independent studies were conducted to investigate the relationship between host resistances
to these two diseases. In the first study 32 genotypes were assessed and no significant correlation between their reactions
to FHB and CR was detected. The second study was based on a QTL analysis of a doubled haploid population derived from a variety
with resistance to both diseases. Results from this study showed that loci conferring resistance to FHB and CR are located
on different chromosomes. Together, these results suggest that, despite a common aetiology, different host genes are involved
in the resistance against FHB and CR in wheat. Thus, although it is possible that genes affecting both diseases may exist
in other germplasm or under different conditions, separate screening seems to be needed in identifying sources of CR resistance. 相似文献
33.
Tunali B Obanor F Erginbaş G Westecott RA Nicol J Chakraborty S 《FEMS microbiology ecology》2012,81(3):596-609
Crown rot and head blight of wheat are caused by the same Fusarium species. To better understand their biology, this study has compared 30 isolates of the three dominant species using 13 pathogenic and saprophytic fitness measures including aggressiveness for the two diseases, saprophytic growth and fecundity and deoxynivalenol (DON) production from saprophytic colonization of grain and straw. Pathogenic fitness was generally linked to DON production in infected tissue. The superior crown rot fitness of Fusarium pseudograminearum was linked to high DON production in the stem base tissue, while Fusarium culmorum and Fusarium graminearum had superior head blight fitness with high DON production in grains. Within each species, some isolates had similar aggressiveness for both diseases but differed in DON production in infected tissue to indicate that more than one mechanism controlled aggressiveness. All three species produced more DON when infecting living host tissue compared with saprophytic colonization of grain or straw, but there were significant links between these saprophytic fitness components and aggressiveness. As necrotrophic pathogens spend a part of their life cycle on dead organic matter, saprophytic fitness is an important component of their overall fitness. Any management strategy must target weaknesses in both pathogenic fitness and saprophytic fitness. 相似文献
34.
DoHarris L Giesler A Humber B Sukumar A Janssen LJ 《Advances in physiology education》2011,35(2):213-218
A wide variety of cellular processes use molecular motors, including processive motors that move along some form of track (e.g., myosin with actin, kinesin or dynein with tubulin) and polymerases that move along a template (e.g., DNA and RNA polymerases, ribosomes). In trying to understand how these molecular motors actually move, many apply their understanding of how man-made motors work: the latter use some form of energy to exert a force or torque on its load. However, quite a different mechanism has been proposed to possibly account for the movement of molecular motors. Rather than hydrolyzing ATP to push or pull their load, they might use their own thermal vibrational energy as well as that of their load and their environment to move the load, capturing those movements that occur along a desired vector or axis and resisting others; ATP hydrolysis is required to make backward movements impossible. This intriguing thermal capture or Brownian ratchet model is relatively more difficult to convey to students. In this report, we describe several teaching aids that are very easily constructed using widely available household materials to convey the concept of a molecular ratchet. 相似文献
35.
Diana C. Tan Gavin R. Flematti Emilio L. Ghisalberti Krishnapillai Sivasithamparam Sukumar Chakraborty Friday Obanor Kithsiri Jayasena Martin J. Barbetti 《Mycotoxin Research》2012,28(2):89-96
An isolated occurrence of Fusarium head blight (FHB) of wheat was detected in the south-west region of Western Australia during
the 2003 harvest season. The molecular identity of 23 isolates of Fusarium spp. collected from this region during the FHB outbreak confirmed the associated pathogens to be F. graminearum, F. acuminatum or F. tricinctum. Moreover, the toxicity of their crude extracts from Czapek-Dox liquid broth and millet seed cultures to brine shrimp (Artemia franciscana) was associated with high mortality levels. The main mycotoxins detected were type B trichothecenes (deoxynivalenol and 3-acetyldeoxynivalenol),
enniatins, chlamydosporol and zearalenone. This study is the first report on the mycotoxin profiles of Fusarium spp. associated with FHB of wheat in Western Australia. This study highlights the need for monitoring not just for the presence
of the specific Fusarium spp. present in any affected grain but also for their potential mycotoxin and other toxic secondary metabolites. 相似文献
36.
N Raaman B Mahendran C Jaganathan S Sukumar V Chandrasekaran 《World journal of microbiology & biotechnology》2012,28(2):627-636
The chromium (CrIII and CrVI) removal capability of Rhizobium leguminosarum was checked by estimating the amount of chromium in the medium before and after inoculation. To determine the efficiency
of R. leguminosarum in removal of chromium, the influence of physical and chemical parameters such as temperature, pH and different concentrations
(0.1–1.0 mM) of trivalent (CrIII) and hexavalent (CrVI) chromium were studied. The chromium removal in aqueous solution by different size of active and inactivated biomass and
immobilized cells of R. leguminosarum in a packed-bed column was also carried out. Results showed that in a medium containing up to 0.5 mM concentration of both
CrIII and CrVI, R. leguminosarum showed optimal growth. The maximum chromium removal was at pH 7.0 and 35°C. Active biomass removed 84.4 ± 3.6% of CrIII and 77.3 ± 4.3% of CrVI in 24 h of incubation time. However, inactivated biomass removed maximum chromium after 36 h of incubation. Immobilized bacterial
cells in a packed-bed column removed 86.4 ± 1.7% of CrIII and 83.8 ± 2.2% of CrVI in 16 and 20 h of incubation time, respectively. 相似文献
37.
Background
Reducing salt intake has been proposed to prevent cardiovascular disease in India. We sought to determine whether salt reductions would be beneficial or feasible, given the worry that unrealistically large reductions would be required, worsening iodine deficiency and benefiting only urban subpopulations.Methods and Results
Future myocardial infarctions (MI) and strokes in India were predicted with a Markov model simulating men and women aged 40 to 69 in both urban and rural locations, incorporating the risk reduction from lower salt intake. If salt intake does not change, we expect ∼8.3 million MIs (95% CI: 6.9–9.6 million), 830,000 strokes (690,000–960,000) and 2.0 million associated deaths (1.5–2.4 million) per year among Indian adults aged 40 to 69 over the next three decades. Reducing intake by 3 g/day over 30 years (−0.1 g/year, 25% reduction) would reduce annual MIs by 350,000 (a 4.6% reduction; 95% CI: 320,000–380,000), strokes by 48,000 (−6.5%; 13,000–83,000) and deaths by 81,000 (−4.9%; 59,000–100,000) among this group. The largest decline in MIs would be among younger urban men, but the greatest number of averted strokes would be among rural men, and nearly one-third of averted strokes and one-fifth of averted MIs would be among rural women. Only under a highly pessimistic scenario would iodine deficiency increase (by <0.0001%, ∼1600 persons), since inadequate iodized salt access—not low intake of iodized salt—is the major cause of deficiency and would be unaffected by dietary salt reduction.Conclusions
Modest reductions in salt intake could substantially reduce cardiovascular disease throughout India. 相似文献38.
Woody plant diversity in relation to environmental factors in a seasonally dry tropical forest landscape 下载免费PDF全文
Handanakere S. Dattaraja Sandeep Pulla Hebbalalu S. Suresh Mavinakoppa S. Nagaraja Chilakunda A. Srinivasa Murthy Raman Sukumar 《植被学杂志》2018,29(4):704-714
Questions
Water availability is known to be a first‐order driver of plant diversity; yet water also affects fire regimes and soil fertility, which, in turn, affect plant diversity. We examined how precipitation, fire and soil properties jointly determine woody plant diversity. Specifically, we asked how woody plant diversity varies along a sharp precipitation gradient (about 600–1,800 mm mean annual precipitation [MAP ]within a ~45‐km distance) exhibiting considerable variation in long‐term fire burn frequency and soil fertility, in a southern Indian seasonally dry tropical forest (SDTF ) landscape.Location
Mudumalai, Western Ghats, India.Methods
Woody plants ≥1‐cm DBH were enumerated in 19 1‐ha permanent plots spanning a range of tropical vegetation types from dry thorn forest, through dry and moist deciduous forest to semi‐evergreen forest. Burn frequencies were derived from annual fire maps. Six measures of surface soil properties – total exchangeable bases (Ca + Mg + K), organic carbon (OC ), total N, pH , plant available P and micronutrients (Fe + Cu + Zn + Mn) were used in the analyses. Five measures of diversity – species richness, Shannon diversity, the rarefied/extrapolated versions of these two measures, and Fisher's α – were modelled as functions of MAP , annual fire burn frequency and the principal components of soil properties.Results
Most soil nutrients and OC increased with MAP , except in the wettest sites. Woody productivity increased with MAP , while fire frequency was highest at intermediate values of MAP . Woody plant diversity increased with MAP but decreased with increasing fire frequency, resulting in two local diversity maxima along the MAP gradient – in the semi‐evergreen and dry thorn forest – separated by a low‐diversity central region in dry deciduous forest where fire frequency was highest. Soil variables were, on the whole, less strongly correlated with diversity than MAP .Conclusions
Although woody plant diversity in this landscape, representative of regional SDTF s, is primarily limited by water availability, our study emphasizes the role of fire as a potentially important second‐order driver that acts to reduce diversity in this landscape.39.
Summary Stable carbon isotope ratios in bone collagen have been used in a variety of dietary studies in modern and fossil animals,
including humans. Inherent in the stable isotope technique is the assumption that the isotopic signature is a reflection of
the diet and is persistent in collagen because this is a relatively inert protein. Carbon isotope analyses of bones from a
southern Indian population of Asian elephant (Elephas maximus), a long-lived mammal that alternates seasonally between a predominantly C3 (browse) and C4 (grass) plant diet, showed two patterns that have important implications for dietary interpretation based on isotopic studies.
Relative to the quantity of the two plant types consumed on average, the δ13C signal in collagen indicated that more carbon was incorporated from C3 plants, possibly due to their higher protein contribution. There was a much greater variance in δ13C values of collagen in sub-adult (range -10.5‰ to-22.7‰, variance=14.51) compared to adult animals (range -16.0‰ to -20.3‰,
variance=1.85) pointing to high collagen turnover rates and non-persistent isotopic signatures in younger, growing animals.
It thus seems important to correct for any significant relative differences in nutritive value of food types and also consider
the age of an animal before drawing definite conclusions about its diet from isotope ratios. 相似文献
40.
HOXA5 regulates expression of the progesterone receptor 总被引:6,自引:0,他引:6