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1.
Dry matter and nutrient inputs through litter fall in a dry tropical forest of India 总被引:1,自引:0,他引:1
Lalji Singh 《Plant Ecology》1992,98(2):129-140
The present paper elucidates the pattern of leaf and non-leaf fall and quantifies of the total annual input of litter in a dry tropical forest of India. In addition, concentration of selected nutrients in various litter species and their annual return to the forest floor are examined. Total annual input of litter measured in litter traps ranged between 488.0–671.0 g m-2 of which 65–72% was leaf litter fall and 28–35% wood litter fall. 73–81% leaves fall during the winter season. Herbaceous litter fall ranged between 80.0–110.0 g m-2 yr-1. The annual nutrient return through litter fall amounted (kg ha-1): 51.6–69.6 N, 3.1–4.3 P, 31.0–40.0 Ca, 14.0–19.0 K and 3.7–5.0 Na, of which 71–77% and 23–29% were contributed by leaf and wood litter fall, respectively for different nutrients. Input of nutrients through herbaceous litter was: 13.0–16.6 for N, 1.0–1.4 for P, 4.0–5.0 for Ca, 7.9–10.5 for K and 0.8–1.0 kg ha-1 yr-1 for Na. 相似文献
2.
The evolutionary relationship of peculiar and poorly known Ganges River dolphin with extinct and extant cetaceans has been in the state of confusion for more than a century. The close resemblance of platanistidae with some of the extinct taxon viz., Dalpiaziniidae and Waipatiidae and their sister group relationship with many of the extant lineages of cetaceans has been reported but none of the alternative hypotheses provide an unambiguous placement for this species. The present study provides insights into the molecular relationships of Platanista with other cetaceans based on comprehensive analyses of the mitochondrial cytochrome b and nuclear interphotoreceptor retinoid-binding protein gene sequences, obtained from 15 specimens of Ganges dolphin from India and Bangladesh. The mean substitution distance analysis of phylogenetically informative characters in the cytochrome b sequences suggested that Platanista gangetica is significantly closer (P<0.001) to Mysticeti than to any other group of toothed whales. However, the conventional methods of phylogenetic reconstruction supported this finding with low to moderate (41-69%) bootstrap values. 相似文献
3.
The N-terminal extension of rusticyanin is a unique structural feature of this protein in the cupredoxin family and has been speculated to be responsible for the extreme acid stability of the protein. We have removed the 35 residues from the N-terminus and show that the resulting -35 mutant is insoluble in aqueous media above pH 5.0 and exists primarily in a hexameric form at lower pHs. Synchrotron radiation circular dichroism (SRCD) and solution X-ray scattering data indicate that much of the beta-sheet structure is retained in acidic solution and indeed there is a small but significant increase in the beta-sheet contribution. We suggest this to be a result of beta-sheet formation between the monomer interfaces. The mutant does not bind copper. These results provide evidence that the unique N-terminus of rusticyanin is not responsible for the acid stability of the hydrophobic beta-barrel core of the protein. 相似文献
4.
Subramanian S Madgula VM George R Mishra RK Pandit MW Kumar CS Singh L 《Genome biology》2002,3(12):preprint00-13
MRD is a database system to access the microsatellite repeats information of genomes such as archea, eubacteria, and other eukaryotic genomes whose sequence information is available in public domains. MRD stores information about simple tandemly repeated k-mer sequences where k= 1 to 6, i.e. monomer to hexamer. The web interface allows the users to search for the repeat of their interest and to know about the association of the repeat with genes and genomic regions in the specific organism. The data contains the abundance and distribution of microsatellites in the coding and non-coding regions of the genome. The exact location of repeats with respect to genomic regions of interest (such as UTR, exon, intron or intergenic regions) whichever is applicable to organism is highlighted. MRD is available on the World Wide Web at and/or . The database is designed as an open-ended system to accommodate the microsatellite repeats information of other genomes whose complete sequences will be available in future through public domain. 相似文献
5.
Deepa Selvi Rani Perundurai S. Dhandapany Pratibha Nallari Periyasamy Govindaraj Lalji Singh Kumarasamy Thangaraj 《Mitochondrion》2010,10(2):166-173
Mutations in PTPN11 gene was responsible for ~50% of the Noonan syndrome (NS), however, we did not find any mutation in PTPN11 in any of seven NS patients analysed. Whereas, the complete mtDNA sequencing revealed 146 mutations, of which five, including one heteroplasmic (A11144R; Thr → Ala) non-synonymous mutation, were novel and exclusively observed in NS patients. Interestingly all the seven probands and their maternal relatives were clustered under a major haplogroup R and its novel sub-haplogroups (R7b1b, R30a1, R30c, T2b7, U9a1) exclusive in NS, therefore we strongly suggest that these haplogroups may influence NS in South Indian populations. 相似文献
6.
Zerjal T Pandya A Thangaraj K Ling EY Kearley J Bertoneri S Paracchini S Singh L Tyler-Smith C 《Human genetics》2007,121(1):137-144
The caste system has persisted in Indian Hindu society for around 3,500 years. Like the Y chromosome, caste is defined at
birth, and males cannot change their caste. In order to investigate the genetic consequences of this system, we have analysed
male-lineage variation in a sample of 227 Indian men of known caste, 141 from the Jaunpur district of Uttar Pradesh and 86
from the rest of India. We typed 131 Y-chromosomal binary markers and 16 microsatellites. We find striking evidence for male
substructure: in particular, Brahmins and Kshatriyas (but not other castes) from Jaunpur each show low diversity and the predominance
of a single distinct cluster of haplotypes. These findings confirm the genetic isolation and drift within the Jaunpur upper
castes, which are likely to result from founder effects and social factors. In the other castes, there may be either larger
effective population sizes, or less strict isolation, or both.
Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorized users.
Tatiana Zerjal and Arpita Pandya contributed equally to this work. 相似文献
7.
Funk SM Verma SK Larson G Prasad K Singh L Narayan G Fa JE 《Molecular phylogenetics and evolution》2007,45(2):427-436
The pygmy hog, Sus salvanius, the smallest and rarest extant suid was first described as the only member of the genus Porcula. It is currently regarded as member of the genus Sus and a sister taxon of the domestic pig/Eurasian wild boar (Sus scrofa). Phylogenetic analyses of 2316 bp from three mtDNA loci (control-region, cytochrome b, 16S) by Bayesian inference and statistical testing of alternative phylogenetic hypotheses all support the original classification of the pygmy hog as a unique genus. Thus, we propose that the species name Porcula salvania should be resurrected. The reclassification will heighten awareness of the need for the future protection and survival of this unique species. 相似文献
8.
9.
Thangaraj K Sridhar V Kivisild T Reddy AG Chaubey G Singh VK Kaur S Agarawal P Rai A Gupta J Mallick CB Kumar N Velavan TP Suganthan R Udaykumar D Kumar R Mishra R Khan A Annapurna C Singh L 《Human genetics》2005,116(6):507-517
Length variation in the human mtDNA intergenic region between the cytochrome oxidase II (COII) and tRNA lysine (tRNAlys) genes has been widely studied in world populations. Specifically, Austronesian populations of the Pacific and Austro-Asiatic populations of southeast Asia most frequently carry the 9-bp deletion in that region implying their shared common ancestry in haplogroup B. Furthermore, multiple independent origins of the 9-bp deletion at the background of other mtDNA haplogroups has been shown in populations of Africa, Europe, Australia, and India. We have analyzed 3293 Indian individuals belonging to 58 populations, representing different caste, tribal, and religious groups, for the length variation in the 9-bp motif. The 9-bp deletion (one copy) and insertion (three copies) alleles were observed in 2.51% (2.15% deletion and 0.36% insertion) of the individuals. The maximum frequency of the deletion (45.8%) was observed in the Nicobarese in association with the haplogroup B5a D-loop motif that is common throughout southeast Asia. The low polymorphism in the D-loop sequence of the Nicobarese B5a samples suggests their recent origin and a founder effect, probably involving migration from southeast Asia. Interestingly, none of the 302 (except one Munda sample, which has 9-bp insertion) from Mundari-speaking Austro-Asiatic populations from the Indian mainland showed the length polymorphism of the 9-bp motif, pointing either to their independent origin from the Mon-Khmeric-speaking Nicobarese or to an extensive admixture with neighboring Indo-European-speaking populations. Consistent with previous reports, the Indo-European and Dravidic populations of India showed low frequency of the 9-bp deletion/insertion. More than 18 independent origins of the deletion or insertion mutation could be inferred in the phylogenetic analysis of the D-loop sequences. 相似文献
10.
Global patterns in human mitochondrial DNA and Y-chromosome variation caused by spatial instability of the local cultural processes
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Kumar V Langstieh BT Madhavi KV Naidu VM Singh HP Biswas S Thangaraj K Singh L Reddy BM 《PLoS genetics》2006,2(4):e53
Because of the widespread phenomenon of patrilocality, it is hypothesized that Y-chromosome variants tend to be more localized geographically than those of mitochondrial DNA (mtDNA). Empirical evidence confirmatory to this hypothesis was subsequently provided among certain patrilocal and matrilocal groups of Thailand, which conforms to the isolation by distance mode of gene diffusion. However, we expect intuitively that the patterns of genetic variability may not be consistent with the above hypothesis among populations with different social norms governing the institution of marriage, particularly among those that adhere to strict endogamy rules. We test the universality of this hypothesis by analyzing Y-chromosome and mtDNA data in three different sets of Indian populations that follow endogamy rules to varying degrees. Our analysis of the Indian patrilocal and the matrilocal groups is not confirmatory to the sex-specific variation observed among the tribes of Thailand. Our results indicate spatial instability of the impact of different cultural processes on the genetic variability, resulting in the lack of universality of the hypothesized pattern of greater Y-chromosome variation when compared to that of mtDNA among the patrilocal populations. 相似文献