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1.
E. A. Shahin R. Spivey 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1986,72(2):164-169
Summary Autotetraploids were established from 8 diploid wild species of section Arachis. In all the autotetraploids the chromosomes paired largely as bivalents even though they possess the ability to pair as multivalents. Pollen and pod fertility in the C1 generation were not directly associated with chromosome pairing. The C2 generation autotetraploids showed a gradual increase in bivalent associations and pollen and pod fertility. The identification of two genomes, A and B, in the diploid species and in the tetraploid, A. hypogaea, of the section Arachis, a fairly good crossability, and the type of chromosome associations observed in hybrids between A. hypogaea and the autotetraploids of wild Arachis species indicated good prospects of utilizing autotetraploids as genetic bridges in transferring desired traits from these taxa into groundnut.Submitted as Journal Article No. 516 by International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) 相似文献
2.
Treatment of newborn rats with clomiphene citrate during the first 5 days of life gave rise to a marked decrease in body mass and to a still greater decrease in gonadal mass. A decrease was also observed in the testicular diameter of the males. The females showed a 43% increase in their estradiol levels over the control and an increase in the sensitivity to gonadotropins. Thyroxine level, which was also determined in view of the known gonadotropin-thyrotropin overlap, showed no change 6 weeks after pretreatment with clomiphene, while the thyroid gland responded to gonadotropin in the same manner as to thyrotropin. 相似文献
3.
Nielsen J; Peixoto AA; Piccin A; Costa R; Kyriacou CP; Chalmers D 《Molecular biology and evolution》1994,11(6):839-853
The region of the clock gene period (per) that encodes a repetitive tract
of threonine-glycine (Thr-Gly) pairs has been compared between Dipteran
species both within and outside the Drosophilidae. All the non-
Drosophilidae sequences in this region are short and present a remarkably
stable picture compared to the Drosophilidae, in which the region is much
larger and extremely variable, both in size and composition. The
accelerated evolution in the repetitive region of the Drosophilidae appears
to be mainly due to an expansion of two ancestral repeats, one encoding a
Thr-Gly dipeptide and the other a pentapeptide rich in serine, glycine, and
asparagine or threonine. In some drosophilids the expansion involves a
duplication of the pentapeptide sequence, but in Drosophila pseudoobscura
both the dipeptide and the pentapeptide repeats are present in larger
numbers. In the nondrosophilids, however, the pentapeptide sequence is
represented by one copy and the dipeptide by two copies. These observations
fulfill some of the predictions of recent theoretical models that have
simulated the evolution of repetitive sequences.
相似文献
4.
Md. Aktar-Uz-Zaman Md. Ariful Islam Md. Shahin Iqbal Md. Jahangir Alam Debashish Sarkar Bander Albogami Ahmed Gaber Akbar Hossain 《Phyton》2023,92(3):883-899
Ensuring food security for the rapidly increasing population and changing climatic scenarios are requisites for
exploiting the genetic divergence of food crops. A study was undertaken to sort out an early maturing chickpea
variety for fitting easily between rice-rice cropping systems in the Eastern Indo-Gangetic Plain of Bangladesh. The
trial was comprised of eight elite lines of chickpea and executed at various localities in Bangladesh from 2014–
15 to 2017–18. The result explored the chickpea genotype, BARI Chola-11 remained superior to the rest of
the elite genotypes for having a short maturity period (100–106 days), and lesser days to 50% flowering (47–
55 days). The same genotype was recorded to have robust vegetative and reproductive yield attributes including
plant height (49–57 cm), podsplant−1 (37–50), and optimum 100 seed weight (19.5–20.6 g). Owing to better yield
attributes, BARI Chola-11 resulted in the maximum seed yield (1200–1500 kg ha−1
) of chickpea and might be
recommended for general adoption in the region for boosting nutritional security status through improved productivity under changing climate. 相似文献
5.
Evolutionary origin of human and primate malarias: evidence from the circumsporozoite protein gene 总被引:8,自引:1,他引:7
We have analyzed the conserved regions of the gene coding for the
circumsporozoite protein (CSP) in 12 species of Plasmodium, the malaria
parasite. The closest evolutionary relative of P. falciparum, the agent of
malignant human malaria, is P. reichenowi, a chimpanzee parasite. This is
consistent with the hypothesis that P. falciparum is an ancient human
parasite, associated with humans since the divergence of the hominids from
their closest hominoid relatives. Three other human Plasmodium species are
each genetically indistinguishable from species parasitic to nonhuman
primates; that is, for the DNA sequences included in our analysis, the
differences between species are not greater than the differences between
strains of the human species. The human P. malariae is indistinguishable
from P. brasilianum, and P. vivax is indistinguishable from P. simium; P.
brasilianum and P. simium are parasitic to New World monkeys. The human P.
vivax-like is indistinguishable from P. simiovale, a parasite of Old World
macaques. We conjecture that P. malariae, P. vivax, and P. vivax-like are
evolutionarily recent human parasites, the first two at least acquired only
within the last several thousand years, and perhaps within the last few
hundred years, after the expansion of human populations in South America
following the European colonizations. We estimate the rate of evolution of
the conserved regions of the CSP gene as 2.46 x 10(-9) per site per year.
The divergence between the P. falciparum and P. reichenowi lineages is
accordingly dated 8.9 Myr ago. The divergence between the three lineages
leading to the human parasites is very ancient, about 100 Myr old between
P. malariae and P. vivax (and P. vivax-like) and about 165 Myr old between
P. falciparum and the other two.
相似文献
6.
Photosynthetic enhancement studies performed at 619 nm (excitation of Systems I and II) and at 446 nm (mainly excitation of System I) revealed an 18% photosynthetic enhancement simultaneously with a 31% reduction in glycolate excretion. This observation supports the hypothesis that some glycolate may be consumed in an oxidation process associated with System I when System II is poorly excited and the supply of electrons from the water splitting process of photosynthesis is low. 相似文献
7.
AH 22216 is a new histamine-H2-receptor antagonist which possesses a triazole ring. When compared to cimetidine, AH 22216 is about 100 times more potent (Ki = 0.21×10–8 M) in inhibiting histamine-stimulated acid secretion in isolated rabbit gastric cells. These two antihistamines have no effect on carbachol-stimulated acid secretion in the system. The data indicate that AH 22216 interacts directly and specifically on the gastric H2-receptor of the parietal cell and are consistent with the reported pharmacological potencies of AH 22216 and cimetidine on histamine-induced gastric-acid secretion in vivo. AH 22216 could thus be a useful therapeutic agent in patients with peptic ulcers. 相似文献
8.
Teymouri Babak Ghiasi Ghalehkandi Jamshid Hassanpour Shahin Aghdam-Shahryar Habib 《International journal of peptide research and therapeutics》2020,26(1):381-387
International Journal of Peptide Research and Therapeutics - The aim of the current study was to determine effect of in ovo feeding of vitamin B12 on hatchability, growth performance and blood... 相似文献
9.
Oula Shahin Nicolas Martin-St Paul Serge Rambal Richard Joffre Franck Richard 《Symbiosis (Philadelphia, Pa.)》2013,61(1):1-12
Understanding the factors underlying the distribution of biodiversity is a challenging issue in ecology. Here, we examined the distribution patterns of ectomycorrhizal fungal diversity across the soil profile in three Quercus ilex forests. Contact exploration type strongly dominated at all sites, but was most prevalent in the upper, organic-rich soil layers. At each site, three quarters of the ectomycorrhizal tips and 59 % of taxa were restricted to the ten first centimeters of the soil profile. The relative abundance of the dominant family Russulaceae increased with increasing soil depth. Species composition varied significantly among sites, with most species being rare. Species that occurred in only one of the three sites accounted for 78.9 % of all species, and 57.3 % of species were represented by a single ECM root tip. Our results suggest that (i) rare species at both local and regional scales contribute to the highly diverse fungal assemblages in Mediterranean forests and (ii) multi-sites studies including the whole soil profile are needed to provide comprehensive overviews of the taxonomic and functional diversities of ectomycorrhizal communities. 相似文献
10.
Anderson Souza Oliveira Leonardo Gizzi Shahin Ketabi Dario Farina Uwe Gustav Kersting 《PloS one》2016,11(4)
Motorized treadmills have been widely used in locomotion studies, although a debate remains concerning the extrapolation of results obtained from treadmill experiments to overground locomotion. Slight differences between treadmill (TRD) and overground running (OVG) kinematics and muscle activity have previously been reported. However, little is known about differences in the modular control of muscle activation in these two conditions. Therefore, we aimed at investigating differences between motor modules extracted from TRD and OVG by factorization of multi-muscle electromyographic (EMG) signals. Twelve healthy men ran on a treadmill and overground at their preferred speed while we recorded tibial acceleration and surface EMG from 11 ipsilateral lower limb muscles. We extracted motor modules representing relative weightings of synergistic muscle activations by non-negative matrix factorization from 20 consecutive gait cycles. Four motor modules were sufficient to accurately reconstruct the EMG signals in both TRD and OVG (average reconstruction quality = 92±3%). Furthermore, a good reconstruction quality (80±7%) was obtained also when muscle weightings of one condition (either OVG or TRD) were used to reconstruct the EMG data from the other condition. The peak amplitudes of activation signals showed a similar timing (pattern) across conditions. The magnitude of peak activation for the module related to initial contact was significantly greater for OVG, whereas peak activation for modules related to leg swing and preparation to landing were greater for TRD. We conclude that TRD and OVG share similar muscle weightings throughout motion. In addition, modular control for TRD and OVG is achieved with minimal temporal adjustments, which were dependent on the phase of the running cycle. 相似文献