Identification of Sarcocystis hominis-like (Protozoa : Sarcocystidae) cyst in water buffalo (Bubalus bubalis) based on 18S rRNA gene sequences

DNA templates were extracted from isolates of Sarcocystis hominis-like cysts collected from cattle and water buffalo, as well as from Sarcocystis fusiformis cysts and Sarcocystis suihominis cysts. The 18S rRNA genes were amplified using DNA from a single

A PCR-based RFLP analysis of Sarcocystis cruzi (Protozoa : Sarcocystidae) in Yunnan province, PR china, reveals the water buffalo (Bubalus bubalis) as a natural intermediate host

A polymerase chain reaction-based restriction fragment length polymorphism (RFLP) approach is used to examine Sarcocystis cruzi-like taxa from the atypical intermediate host, water buffalo, in Yunnan, People's Republic of China. The loci examined lie with

The role of MC1R gene in buffalo coat color

Melanocortin-1 receptor (MC1R) plays a major role in pigmentation in many species. To investigate if the MC1R gene is associated with coat color in water buffalo, the coding region of MC1R gene of 216 buffalo samples was sequenced, which included 49 black river buffalo (Murrah and Nili-Ravi), 136 swamp buffalo (Dehong, Diandongnan, Dechang, Guizhou, and Xilin) with white and gray body, and 31 hybrid offspring of river buffalo Nili-Ravi (or Murrah) and swamp buffalo. Among the three variation sites found, SNP684 was synonymous, while SNP310 and SNP384 were nonsynonymous, leading to p.S104G and p.I128M changes, respectively. Only Individuals carrying homozygote E-BR/E-BR were black. The genotype and phenotype analysis of the hybrid offspring of black river buffalo and gray swamp buffalo further revealed that the river buffalo type allele E-BR or the allele carrying the amino acid p.104S was important for the full function of MC1R. The in silico functional analysis showed that the amino acid substitutions p.G104S and p.M128I had significant impact on the function of MC1R. Above results indicate that the allele E-BR or the allele carrying the amino acid p.104S was associated with the black coat color in buffalo.

生殖激素对奶水牛卵母细胞成熟及发育潜能的影响

本试验以屠宰场获取的奶水牛卵巢为试验材料,收集卵母细胞进行体外成熟培养(IVM)、体外受精(IVf)及早期胚胎培养(IVC).研究激素(FSH、LH、E2、P4)的不同浓度对奶水牛卵母细胞成熟和早期胚胎发育的影响,以期探讨奶水牛卵母细胞成熟和早期胚胎体外培养发育机制,优选不同激素的最佳浓度.结果表明:添加FSH试验组奶水牛颗粒细胞扩散率和卵裂率高于未添加试验组(P<0.05);添加LH试验组奶水牛颗粒细胞扩散率、卵裂率及8-细胞率与未添加试验组比较,差异不明显(P>0.05);17β-E2试验组(1.0μg/mL)的奶水牛颗粒细胞扩散率、卵裂率及8-细胞率高于未添加试验组(P<0.05);添加P4试验各组(0.9μg/mL、1.2μg/mL)的颗粒细胞扩散率明显低于未添加试验组(P<0.01).

Characterization of Sarcocystis species in domestic animals using a PCR-RFLP analysis of variation in the 18S rRNA gene: a cost-effective and simple technique for routine species identification

Thirteen restriction endonucleases were used to investigate nucleotide sequence variation in the 18S rRNA DNA of 88 individuals from ten Sarcocystis taxa collected as cysts from their intermediate hosts, swine, cattle and water buffalo. A DNA sequence of

牛胚胎在BRL/mTCM199和HECM-6/mTCM199培养体系中发育潜能的探讨

将受精卵置于下列两种培养体系中进行体外培养:(1)Buffalo rat liver细胞与改进的TCM199培养液共同培养系统(BRL/mTCM199);(2)半确定培养液两步培养系统[无血清的金黄地鼠培养液与改进的TCM199培养液(HECM-6/mTCM199]。结果表明:后者的囊胚率(50%)明显高于前者的囊胚率(41%,P<0.01)。表明牛胚胎早期分裂可在无蛋白培养条件下进行,并且在此培养条件下有良好的后续发育能力。这可能与两步培养体系中葡萄糖和氨基酸浓度不同有关。

High-quality-factor EH modes in microcylinder resonators predicted by 3D FDTD simulation

The mode characteristis of a microcylinders with center layer thickness 0.2 mu m and radius 1 mu m are investigated by the three-dimensional (31)) finite-difference time-domain (FDTD) technique and the Pade approximation. The mode quality factor (Q-factor) of the EH71 mode obtained by 3D FDTD increase with the increase of the refractive index of the cladding layer n(2) as n(2) smaller than 3.17, and can be as large as 2.4 x 10(4) as the vertical refractive index distribution is 3.17/3.4/3.17, which is much larger than that of the HE71 mode with the same vertical refractive index distribution.

Growth mechanism of InGaAlAs waveguides by narrow stripe selective MOVPE

Growth mechanism of InGaAlAs waveguides by narrow stripe selective MOVPE has been studied. Both the InGaAlAs bulk waveguides and the InGaAlAs MQW waveguides were successful grown on the patterned substrates at optimized growth conditions. The mask stripe width varied from 0 to 40 mu m, while the window region width between a pair of mask stripes was fixed 2.5 mu m. These selectively grown waveguides were covered by specific InP layers, which can keep the InGaAlAs waveguides from being oxidized during the fabrication of devices. In particular, there exhibit strong dependences of the photoluminescence (PL) spectrum on the mask stripe width for the samples. The results were explained in considering both the migration effect from a masked region (MMR) and the lateral vapor diffusion effect (LVD).

Anomalous temperature-dependent bimodal size evolution of InAs quantum dots on vicinal GaAs(100) substrates

Temperature-dependent bimodal size evolution of InAs quantum dots on vicinal GaAs(100) substrates grown by metalorganic chemical vapor deposition (MOCVD) is studied. An abnormal trend of the evolution on temperature is observed. With the increase of the growth temperature, while the density of the large dots decreases continually, that of the small dots first grows larger when temperature was below 520 degrees C, and then there is a sudden decrease at 535 degrees C. Photoluminescence (PL) studies show that QDs on vicinal substrates have a narrower PL line width, a longer emission wavelength and a larger PL intensity.

High-field cyclotron resonance and electron-phonon interaction in modulation-doped multiple quantum well structures

A systematic study of electron cyclotron resonance (CR) in two sets of GaAs/Al0.3Ga0.7As modulation-doped quantum-well samples (well widths between 12 and 24 nm) has been carried out in magnetic fields up to 30 T. Polaron CR is the dominant transition in the region of GaAs optical phonons for the set of lightly doped samples, and the results are in good agreement with calculations that include the interaction with interface optical phonons. The results from the heavily doped set are markedly different. At low magnetic fields (below the GaAs reststrahlen region), all three samples exhibit almost identical CR which shows little effect of the polaron interaction due to screening and Pauli-principle effects. Above the GaAs LO-phonon region (B > similar to 23 T), the three samples behave very differently. For the most lightly doped sample (3 x 10(11) cm(-2)) only one transition minimum is observed, which can be explained as screened polaron CR. A sample of intermediate density (6 x 10(11) cm(-2)) shows two lines above 23 T; the higher frequency branch is indistinguishable from the positions of the single line of the low density sample. For the most heavily, doped sample (1.2 x 10(12) cm(-2)) there is no evidence of high frequency resonance, and the strong, single line observed is indistinguishable from the lower branch observed from sample with intermediate doping density. We suggest that the low frequency branch in our experiment is a magnetoplasmon resonance red-shifted by disorder, and the upper branch is single-particle-like screened polaron CR. (C) 1998 Elsevier Science B.V. All rights reserved.

Resonant magnetopolaron effects in GaAs/AlGaAs multiple quantum well structures

A detailed experimental study of electron cyclotron resonance (CR) has been carried out at 4.2 K in three modulation-doped GaAs/Al0.3Ga0.7As multiple quantum well samples in fields up to 30 T. A strong avoided-level-crossing splitting of the CR energies due to resonant magnetopolaron effects is observed for all samples near the GaAs reststrahlen region. Resonant splittings in the region of AlAs-like interface phonon modes of the barriers are observed in two samples with narrower well width and smaller doping concentration. The interaction between electrons and the AlAs interface optical phonon modes has been calculated for our specific sample structures in the framework of the memory-function formalism. The calculated results are in good agreement with the experimental results, which confirms our assignment of the observed splitting near the AlAs-like phonon region is due to the resonant magnetopolaron interaction of electrons in the wells with AlAs-like interface phonons. (C) 1998 Elsevier Science B.V. All rights reserved.

Origin of mitochondrial DNA diversity of domestic yaks

Background: The domestication of plants and animals was extremely important anthropologically. Previous studies have revealed a general tendency for populations of livestock species to include deeply divergent maternal lineages, indicating that they were domesticated in multiple, independent events from genetically discrete wild populations. However, in water buffalo, there are suggestions that a similar deep maternal bifurcation may have originated from a single population. These hypotheses have rarely been rigorously tested because of a lack of sufficient wild samples. To investigate the origin of the domestic yak (Poephagus grunnies), we analyzed 637 bp of maternal inherited mtDNA from 13 wild yaks (including eight wild yaks from a small population in west Qinghai) and 250 domesticated yaks from major herding regions.Results: The domestic yak populations had two deeply divergent phylogenetic groups with a divergence time of > 100,000 yrs BP. We here show that haplotypes clustering with two deeply divergent maternal lineages in domesticated yaks occur in a single, small, wild population. This finding suggests that all domestic yaks are derived from a single wild gene pool. However, there is no clear correlation of the mtDNA phylogenetic clades and the 10 morphological types of sampled yaks indicating that the latter diversified recently. Relatively high diversity was found in Qinghai and Tibet around the current wild distribution, in accordance with previous suggestions that the earliest domestications occurred in this region. Conventional molecular clock estimation led to an unrealistic early dating of the start of the domestication. However, Bayesian estimation of the coalescence time allowing a relaxation of the mutation rateConclusion: The information gathered here and the previous studies of other animals show that the demographic histories of domestication of livestock species were highly diverse despite the common general feature of deeply divergent maternal lineages. The results further suggest that domestication of local wild prey ungulate animals was a common occurrence during the development of human civilization following the postglacial colonization in different locations of the world, including the high, arid Qinghai-Tibetan Plateau.