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1.
T. Srinivas M. K. Bhashyam Nagin Chand Sila Bhattacharya S. Sreedhara Murthy H. V. Narasimha 《Economic botany》1991,45(4):503-510
Twenty varieties of maize (Zea mays, Poaceae) were studied through 11 attributes in three to seven randomly selected plants of each variety with a view to understanding the effect of cob characters on technologically desirable grain qualities. Canonical discriminant analysis showed thatproductivity (determined by total grain weight/cob, cob diameter and average grain weight) was the most discriminating among varieties followed by round grains fraction (represented by whole top and middle flat grains, number of rows and grain count/surface area), middle flat grains (composed of middle flat grains and grain count/surface area) and shape of the cob (determined by shape index, total grain weight/cob and cob diameter), which accounted for 35.1, 18.3, 12.2, and 9.8% of the total variance, respectively. In the light of these results, tentative norms have been suggested to evolve maize varieties of superior technological properties and yet retain high productivity. A cylindrical cob of large diameter with highest number of grains/area and smallest possible number of rows together constituted an ideal combination to achieve the objectives. Such possibilities in the light of available information are discussed. 相似文献
2.
Mapping Soil Properties of Africa at 250 m Resolution: Random Forests Significantly Improve Current Predictions 总被引:3,自引:0,他引:3
Tomislav Hengl Gerard B. M. Heuvelink Bas Kempen Johan G. B. Leenaars Markus G. Walsh Keith D. Shepherd Andrew Sila Robert A. MacMillan Jorge Mendes de Jesus Lulseged Tamene Jér?me E. Tondoh 《PloS one》2015,10(6)
80% of arable land in Africa has low soil fertility and suffers from physical soil problems. Additionally, significant amounts of nutrients are lost every year due to unsustainable soil management practices. This is partially the result of insufficient use of soil management knowledge. To help bridge the soil information gap in Africa, the Africa Soil Information Service (AfSIS) project was established in 2008. Over the period 2008–2014, the AfSIS project compiled two point data sets: the Africa Soil Profiles (legacy) database and the AfSIS Sentinel Site database. These data sets contain over 28 thousand sampling locations and represent the most comprehensive soil sample data sets of the African continent to date. Utilizing these point data sets in combination with a large number of covariates, we have generated a series of spatial predictions of soil properties relevant to the agricultural management—organic carbon, pH, sand, silt and clay fractions, bulk density, cation-exchange capacity, total nitrogen, exchangeable acidity, Al content and exchangeable bases (Ca, K, Mg, Na). We specifically investigate differences between two predictive approaches: random forests and linear regression. Results of 5-fold cross-validation demonstrate that the random forests algorithm consistently outperforms the linear regression algorithm, with average decreases of 15–75% in Root Mean Squared Error (RMSE) across soil properties and depths. Fitting and running random forests models takes an order of magnitude more time and the modelling success is sensitive to artifacts in the input data, but as long as quality-controlled point data are provided, an increase in soil mapping accuracy can be expected. Results also indicate that globally predicted soil classes (USDA Soil Taxonomy, especially Alfisols and Mollisols) help improve continental scale soil property mapping, and are among the most important predictors. This indicates a promising potential for transferring pedological knowledge from data rich countries to countries with limited soil data. 相似文献
3.
Adnan Ayhanci Sibel Günes Varol Sahinturk Sila Appak Ruhi Uyar Mustafa Cengiz Yilmaz Altuner Suzan Yaman 《Biological trace element research》2010,136(2):171-179
The anticancer drug cyclophosphamide (CP) has nephrotoxic effects besides its urotoxicity, which both in turn limit its clinical
utility. The nephrotoxicity of CP is less common compared to its urotoxicity, and not much importance has been given for the
study of mechanism of CP-induced nephrotoxicity so far. Overproduction of reactive oxygen species (ROS) during inflammation
is one of the reasons of the kidney injury. Selenoproteins play crucial roles in regulating ROS and redox status in nearly
all tissues; therefore, in this study, the nephrotoxicity of CP and the possible protective effects of seleno l-methionine (SLM) on rat kidneys were investigated. Forty-two Sprague–Dawley rats were equally divided into six groups of seven
rats each. The control group received saline, and other rats were injected with CP (100 mg/kg), SLM (0.5 or 1 mg/kg), or CP + SLM
intraperitoneally. Malondialdehyde (MDA) and glutathione (GSH) levels in kidney homogenates of rats were measured, and kidney
tissues were examined under the microscope. CP-treated rats showed a depletion of renal GSH levels (28% of control), while
CP + SLM-injected rats had GSH values close to the control group. MDA levels increased 36% of control following CP administration,
which were significantly decreased after SLM treatment. Furthermore, these biochemical results were supported by microscopical
observations. In conclusion, the present study not only points to the therapeutic potential of SLM in CP-induced kidney toxicity
but also indicates a significant role for ROS and their relation to kidney dysfunction. 相似文献
4.
5.
Background
Molluscs are the most diverse marine phylum and this high diversity has resulted in considerable taxonomic problems. Because the number of species in Canadian oceans remains uncertain, there is a need to incorporate molecular methods into species identifications. A 648 base pair segment of the cytochrome c oxidase subunit I gene has proven useful for the identification and discovery of species in many animal lineages. While the utility of DNA barcoding in molluscs has been demonstrated in other studies, this is the first effort to construct a DNA barcode registry for marine molluscs across such a large geographic area.Methodology/Principal Findings
This study examines patterns of DNA barcode variation in 227 species of Canadian marine molluscs. Intraspecific sequence divergences ranged from 0–26.4% and a barcode gap existed for most taxa. Eleven cases of relatively deep (>2%) intraspecific divergence were detected, suggesting the possible presence of overlooked species. Structural variation was detected in COI with indels found in 37 species, mostly bivalves. Some indels were present in divergent lineages, primarily in the region of the first external loop, suggesting certain areas are hotspots for change. Lastly, mean GC content varied substantially among orders (24.5%–46.5%), and showed a significant positive correlation with nearest neighbour distances.Conclusions/Significance
DNA barcoding is an effective tool for the identification of Canadian marine molluscs and for revealing possible cases of overlooked species. Some species with deep intraspecific divergence showed a biogeographic partition between lineages on the Atlantic, Arctic and Pacific coasts, suggesting the role of Pleistocene glaciations in the subdivision of their populations. Indels were prevalent in the barcode region of the COI gene in bivalves and gastropods. This study highlights the efficacy of DNA barcoding for providing insights into sequence variation across a broad taxonomic group on a large geographic scale. 相似文献6.
Katie J Torley Juliano C da Silveira Peter Smith Russell V Anthony DN Rao Veeramachaneni Quinton A Winger Gerrit J Bouma 《Reproductive biology and endocrinology : RB&E》2011,9(1):2
Background
Gonadal differentiation in the mammalian fetus involves a complex dose-dependent genetic network. Initiation and progression of fetal ovarian and testicular pathways are accompanied by dynamic expression patterns of thousands of genes. We postulate these expression patterns are regulated by small non-coding RNAs called microRNAs (miRNAs). The aim of this study was to identify the expression of miRNAs in mammalian fetal gonads using sheep as a model. 相似文献7.
Molecular evolution of mitochondrial 12S RNA and cytochrome b sequences in the pantherine lineage of Felidae 总被引:4,自引:2,他引:2
DNA sequence comparisons of two mitochondrial DNA genes were used to infer
phylogenetic relationships among 17 Felidae species, notably 15 in the
previously described pantherine lineage. The polymerase chain reaction
(PCR) was used to generate sequences of 358 base pairs of the mitochondrial
12S RNA gene and 289 base pairs of the cytochrome b protein coding gene.
DNA sequences were compared within and between 17 felid and five nonfelid
carnivore species. Evolutionary trees were constructed using phenetic,
cladistic, and maximum likelihood algorithms. The combined results
suggested several phylogenetic relationships including (1) the recognition
of a recently evolved monophyletic genus Panthera consisting of Panthera
leo, P. pardus, P. onca, P. uncia, P. tigris, and Neofelis nebulosa; (2)
the recent common ancestry of Acinonyx jubatus, the African cheetah, and
Puma concolor, the American puma; and (3) two golden cat species, Profelis
temmincki and Profelis aurata, are not sister species, and the latter is
strongly associated with Caracal caracal. These data add to the growing
database of vertebrate mtDNA sequences and, given the relatively recent
divergence among the felids represented here (1-10 Myr), allow 12S and
cytochrome b sequence evolution to be addressed over a time scale different
from those addressed in most work on vertebrate mtDNA.
相似文献
8.
The genus Plutella was thought to be represented in Australia by a single introduced species, Plutella xylostella (Linnaeus), the diamondback moth. Its status as a major pest of cruciferous crops, and the difficulty in developing control strategies has motivated broad-ranging studies on its biology. Prior genetic work has generally supported the conclusion that populations of this migratory species are connected by substantial gene flow. However, the present study reveals the presence of two genetically divergent lineages of this taxonin Australia. One shows close genetic and morphological similarity with the nearly cosmopolitan Plutella xylostella. The second lineage possesses a similar external morphology, but marked sequence divergence in the barcode region of the cytochrome c oxidase I gene, coupled with clear differences in genitalia. As a consequence, members of this lineage are described as a new species, Plutella australiana Landry & Hebert, which is broadly distributed in the eastern half of Australia. 相似文献
9.
Rakesh Sanabam Bharat Gopalrao Somkuwar Gourshyam Thingnam Sila Moirangthem Pratap Jyoti Handique Sunitibala Huidrom 《Bioinformation》2012,8(17):838-840
The rich wealth of Citrus genetic resources makes India to enjoy a remarkable position in the “Citrus belt of the world”. We have
developed CIBMAN, a unique database on Citrus biodiversity of Manipur which comprises 33 accessions collected through
extensive survey for more than three years. CIBMAN provides integrated access to Citrus species through sophisticated web interface
which has following capabilities a) morphological details, b) socio-economic details, c) taxonomic details and d) geographical
distribution. Morphological variability among Citrus accessions is due to variance in their genome which contributes to diverse
agronomical traits and diverse bioactive compounds of high value. This diverse gene pool can be potential source for genetic
improvement of existing cultivars and rootstocks. Systematic collection, characterization and conservation of the underutilized or
lesser exploited varieties is required for incorporating in breeding program and conserve the germplasm from ever going on
genetic erosion. This database will be useful for scientific validations and updating of traditional wisdom in bioprospecting aspects
especially industrialization of Citrus found in the state. Further, the features will be suited for detailed investigation on potential
medicinal and edible Citrus that make CIBMAN a powerful tool for sustainable management.
Availability
http://ibsd.gov.in/cibman 相似文献10.
Developmental regulation of spine and filopodial motility in primary visual cortex: reduced effects of activity and sensory deprivation 总被引:2,自引:0,他引:2
Dendritic protrusions are highly motile during postnatal development. Although spine morphological plasticity could be associated with synaptic plasticity, the function of rapid spine/filopodial motility is still unknown. To investigate the role of spine motility in the development of the visual cortex and its relation with critical periods, we used two-photon imaging of neurons from layers receiving visual input in developing mouse primary visual cortex and compared motility between control and visually deprived animals. Spine and filopodia motility was prominent during early synaptogenesis (P11-P13) but greatly decreased after P15. This "switch" was coincident with a 2.5-fold increase in protrusion density and spine formation. Spine motility was not regulated during the critical period for monocular deprivation (P19-P34). Moreover, delaying the critical period by dark rearing did not delay the normal developmental decrease of spine motility, but caused a modest further reduction in motility at P28-P35. Dark rearing and enucleation also mildly reduced spine motility before eye opening and dark rearing reduced the proportion of filopodia. We conclude that (1) rapid spine motility is not related to critical period plasticity, but is likely to play a role in early synaptogenesis, and (2) neuronal activity stimulates spine motility during synaptogenesis and promotes the appearance of dendritic filopodia. 相似文献