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PubMed2002

[Characteristics and disturbance status of gaps in subalpine fir forest in southeast Tibet].

Characteristics and disturbance status of gaps, including gap size, disturbance frequency, forming patterns of gaps, and quantity of the tree in gap, in subalpine fir forest in Southeast Tibet were studied. The results showed that expanded gaps accounted for 41.73% and canopy gaps accounted for 14.71% of land area in the forest. Averagely, 0.82% and 0.29% of forest area were transformed into expanded and canopy gaps every year. The velocity of gap forming was 0.31 ind.hm-2.yr-1. The disturbance cycle of gaps was 345 yr. Among 16 investigated gaps, there were 78 gap-markers in total, and there were averagely 4.88 trees in each gap. The main reasons of gap forming were gap-markers fallen as well as uprooted and withered, and their external force was strong wind. The possibility of gaps forming reached the maximum while the diameter of arbors was 40-60 cm and the high was 15-20 m in the main forest layer. Gaps were formed by many disturbances in different age in the subalpine fir forest in Southeast Tibet..

Abies↗
PubMed2001

[Studies on anamorph of Cordyceps sinensis (Berk) from Naqu Tibet].

OBJECTIVE: To isolate and determine the strain of anamorph of Cordyceps sinensis collected from Naqu Tibet. METHOD: Isolating the strains of anamorph of Cordyceps sinensis collected from Baqing Shuoxian, Biru Counties by means of the ascope, tissue, ossified larva and body liquid. RESULT: Same strain of anamorph of Cordyceps sinensis was obtained with 4 different methods. CONCLUSION: The strain of Hirsutella sinensis is the anamorph of C. sinensis from Naqu Tibet.

Animals↗
PubMed2004

[Effects of gap in primitive subalpine fir forest on diversity of herb and shrub in Tibet].

Effects of gap in primitive fir forest in southeast Tibet on species diversity of herb and shrub were studied. The results showed that species composition, distribution and diversity in gap were different from those in non-gap. The improvement of illumination and other habitat conditions resulted in richer species of herb and shrub in gap. There were shade-tolerant and photophilic herb species and shrub species in gap, however, only shade-tolerant herb species and shrub species grew in non-gap. Species diversity and evenness in gap were higher than in non-gap. The diminutive similar coefficient between herb and shrub communities showed that certain difference existed between herb and shrub communities in stands of gap and non-gap. The similar coefficients were little correlative between gap area and communities. Gap was important to improve growth of herb and shrub and maintain species diversity of primitive subalpine fir forest in southwest Tibet.

Abies↗
PubMed2005

[Determination of HLA-DRB1 gene polymorphism in Luoba ethnic group of Tibet].

OBJECTIVE: To investigate the frequencies of allele and genotype of HLA-DRB1 gene in Luoba ethnic group. METHODS: HLA-DRB1 genes from 92 individuals of Luoba ethnic group in Tibet Autonomous region were investigated, using PCR-SSO (polymerase chain reaction -sequence specific oligo-nucleotide) genotyping methods. We compared allele frequencies of Luoba population in HLA-DRB1 locus with that of various ethnic groups distributed worldwide, constructed the phylogenetic tree by UPGMA (unweighted pair group method with arithmetic mean), and counted genetic distance by Nei measure. RESULTS: Of the 11 DRB1 alleles detected, the two most common genes were DRBI * 04( gene frequency: 27.20% ) and DRB * 12 (25.50%) , which covered 52.70% of the total alleles detected from Luoba ethnic group. The frequencies of HLA-DRB1 * 14(15.20% ), DRB1 * 15(9.80% ) and DRB1 * 08(8.20% ) were more than 5%. Luoba was unique in the distribution of HLA alleles. The genetic distance between Luoba and Tibetan was closer than that with other population. A dendrogram based on the DRB1 genes by cluster analysis suggested that Luoba ethnic group might cluster with Tibetan firstly, then cluster with other population living in China (except Uygr) , and cluster with Caucasian and Black finally. CONCLUSION: The HLA-DRBI gene frequency of Luoba individuals in Tibet Linzhi had some differences compared with that of other Chinese population. The kindred relation between Luoba and Tibetan was closer than that with other population, which was coincident with the results of ethnology, history and sociology.

China↗
PubMed2005

[Comparative analysis of sequences of the 5S rDNA NTS in wild close relatives of barley from Tibet of China].

Tibet is a center of distribution and differentiation of genus Hordeum in China,and has a great deal of species resource. The sequences of the nontranscribed intergenic spacer (NTS) region of 5S nuclear ribosomal DNA was studied in 18 varieties of the close relative of wild barley (Hordeum spontaneum) from different geographical regions in Tibet and Turkmenistan. These sequences were determined by sequencing the clones of PCR products. Alignment of sequences revealed that the 5S rDNA NTS contained two comparatively conservative regions, A and B, and a variable TAG repeat (V). The number of TAG repeats varies from 4-17, also including several transitions and conversions (TAG-->TCG, TAG-->TAC). The total size of the conservative regions was from 168 -169 bp, and the sequence length variation was only 1 bp. The GC content (%) of the conservative sequence was 43.8% and the homologous of that nearly 98.2% -100%. The number of variable sites was 12 (7.1%). In general, there were more transitions than conversions in the variation sites,and the ratios of transition/conversion were 1.0 - 2.0. NTS polymorphism of 5S rDNA was mainly determined by polymorphism of TAG repeats. The molecular system-tree showed that the NTS should be a useful marker to classify the accessions in Hordeum.

Base Sequence↗
PubMedDate not supplied

[A nutritional survey in Tibet].

We present the most striking results of a nutritional assessment held in Tibet from May to July 1990, performed at the request of the Health Authorities of the Tibet Autonomous Region. Using a cut-off value which adjusts for the haemoglobin increase with increasing altitude, 40% of the women of reproductive age were considered anaemic. However, the distribution of their haemoglobin values was gaussian with a mean value of 13.6%. Apparently, the Tibetans respond differently to high altitude, compared to other populations living at high altitudes. Goitre remains a problem despite the goitre control program. Rickets, investigated by clinical signs, was prevalent in 9.2% of the children 0 to 6 years old. Rural children were shorter and lighter than urban ones and started to accumulate their deficit earlier.

Adolescent↗
PubMed1997

[10 years after Chernobyl--radioactivity of mother's milk-- measurements from Tirol, Tibet and Nepal].

10 years after the Chernobyl disaster gamma radioactivity from Cs-137 was determined in 53 breast milk samples from Tyrol, as well as 9 samples from Tibet and 2 from Nepal by means of a gamma-spectrometer with a germanium detector. In contrast to the values obtained within a few days, and again 1 year after the nuclear plant catastrophe, all samples from Tyrol showed gamma radioactivity levels (median 0.07 nCi/l; range 0.02-0.20 nCi/l) which were now below the limit laid down for baby food in Austria (0.3 nCi/l-11.1 Bq). The samples from Tibet and Nepal registered a slightly higher level of gamma radioactivity (median 0.16 nCi/l; range 0.16-0.41 nCi/l).

Animals↗
PubMed1999

[Linkage studies of a familial spastic paraplegia pedigree from Tibet].

OBJECTIVE: To study the location of disease-related gene in a hereditary spastic paraplegia family with autosomal dominant inheritance in Tibet. METHODS: The AD-HSP family in Tibet was analyzed by linkage studies using 9 highly polymorphic microsatellite DNA markers at three chromosomal regions. RESULTS: The maxium Lod- Score of D14S264 was 0.5163(theta=0.05); of D14S75, 2. 1072 (theta=0);+D14S69, 0.2840 (theta=0.10); of D14S266, 0.9311 (theta=0);of D14S66, 0.7991(theta=0);OF GABRB3, 0(theta =0.40);of D15S128, 0(theta=0.40); of D2S2255, 0 (theta=0.40);and of D2S2347,0(theta=0.40). CONCLUSION: In this Tibetian family, the disease-related gene is linked to D14S75 locus of SPG3 region.

Female↗
PubMed1987

Hemoglobin concentration of pastoral nomads permanently resident at 4,850-5,450 meters in Tibet.

This paper presents data on the hemoglobin concentration of a sample of 103 pastoral nomads who are lifelong residents of Phala, at 4,850-5,450 m, on the northern plateau of the Tibet Autonomous Region of the Peoples' Republic of China. This native population resides at the highest altitude of which we are aware and is thus exposed to the most extreme chronic hypoxic stress. However, they do not exhibit the most pronounced physiological adaptations, i.e., hemoglobin concentrations exceeding those found in all other high-altitude populations. Adult male and female mean hemoglobin concentrations of 18.2 and 16.7 gm/dl, respectively, were found. These data, in conjunction with earlier studies of ethnic Tibetans living at 3,400 m, demonstrate a pattern of increasing hemoglobin concentration (erythrocytosis) at increasing altitude of residence in the Himalayas and Tibet. At the same time, however, the hemoglobin concentration is lower than that found among Andean highlanders. These new data raise the possibility of quantitative population differences in hematological adaptation to high altitude hypoxia.

Adolescent↗
PubMed1999

Southern Tibet Detachment System at Khula Kangri, Eastern Himalaya: A Large-Area, Shallow Detachment Stretching into Bhutan?

A new map and cross sections of the Khula Kangri and Kankar Pünzum-Monlakarchung High Himalayan ranges in the Tibet-Bhutan frontier area are presented from integration of unpublished mapping from the summit section of Khula Kangri and new remote sensing together with previous mapping. The ranges define an orographic bifurcation of the High Himalaya that results in a north-south repetition of the main geological section and coincides with the morphological repetition. The Southern Tibet Detachment System that juxtaposes the Tethyan sedimentary rocks against the gneisses and granites of the High Himalayan Crystalline can be continuously traced around both ranges and is not imbricated. Postdetachment kilometer-scale flexure and faulting account for the features of the observed bifurcation. The true map extent of the Khula Kangri and Monlakarchung-Passalum granite batholiths is now apparent. We propose that the two plutons are part of the same originally continuous body.

Journal Article↗
PubMed2004

InSAR observations of low slip rates on the major faults of western Tibet.

Two contrasting views of the active deformation of Asia dominate the debate about how continents deform: (i) The deformation is primarily localized on major faults separating crustal blocks or (ii) deformation is distributed throughout the continental lithosphere. In the first model, western Tibet is being extruded eastward between the major faults bounding the region. Surface displacement measurements across the western Tibetan plateau using satellite radar interferometry (InSAR) indicate that slip rates on the Karakoram and Altyn Tagh faults are lower than would be expected for the extrusion model and suggest a significant amount of internal deformation in Tibet.

Journal Article↗
PubMed1996

Partially Molten Middle Crust Beneath Southern Tibet: Synthesis of Project INDEPTH Results

INDEPTH geophysical and geological observations imply that a partially molten midcrustal layer exists beneath southern Tibet. This partially molten layer has been produced by crustal thickening and behaves as a fluid on the time scale of Himalayan deformation. It is confined on the south by the structurally imbricated Indian crust underlying the Tethyan and High Himalaya and is underlain, apparently, by a stiff Indian mantle lid. The results suggest that during Neogene time the underthrusting Indian crust has acted as a plunger, displacing the molten middle crust to the north while at the same time contributing to this layer by melting and ductile flow. Viewed broadly, the Neogene evolution of the Himalaya is essentially a record of the southward extrusion of the partially molten middle crust underlying southern Tibet.

Journal Article↗
PubMed1996

INDEPTH Wide-Angle Reflection Observation of P-Wave-to-S-Wave Conversion from Crustal Bright Spots in Tibet

Three-component wide-angle seismic data acquired in southern Tibet during Project INDEPTH show strong P-to-S converted reflections from reflectors that are aligned at a depth of approximately 15 kilometers beneath the northern Yadong-Gulu rift. These converted reflections are locally higher in amplitude than the corresponding P-wave reflections. Modeling of reflection mode conversion as a function of incidence angle indicates that this condition obtains for a reflector that is a solid over fluid interface; it is not typical of a solid-solid interface. The likely candidates for a fluid trapped within the crystalline crust of southern Tibet are granitic magma and water (brine).

Journal Article↗
PubMed1996

Evidence from Earthquake Data for a Partially Molten Crustal Layer in Southern Tibet

Earthquake data collected by the INDEPTH-II Passive-Source Experiment show that there is a substantial south to north variation in the velocity structure of the crust beneath southern Tibet. North of the Zangbo suture, beneath the southern Lhasa block, a midcrustal low-velocity zone is revealed by inversion of receiver functions, Rayleigh-wave phase velocities, and modeling of the radial component of teleseismic P-waveforms. Conversely, to the south beneath the Tethyan Himalaya, no low-velocity zone was observed. The presence of the midcrustal low-velocity zone in the north implies that a partially molten layer is in the middle crust beneath the northern Yadong-Gulu rift and possibly much of southern Tibet.

Journal Article↗
PubMed1997

Surface Deformation and Lower Crustal Flow in Eastern Tibet

Field observations and satellite geodesy indicate that little crustal shortening has occurred along the central to southern margin of the eastern Tibetan plateau since about 4 million years ago. Instead, central eastern Tibet has been nearly stationary relative to southeastern China, southeastern Tibet has rotated clockwise without major crustal shortening, and the crust along portions of the eastern plateau margin has been extended. Modeling suggests that these phenomena are the result of continental convergence where the lower crust is so weak that upper crustal deformation is decoupled from the motion of the underlying mantle. This model also predicts east-west extension on the high plateau without convective removal of Tibetan lithosphere and without eastward movement of the crust east of the plateau.

Journal Article↗
PubMed1999

Seismic Evidence for a Detached Indian Lithospheric Mantle Beneath Tibet.

P-to-S converted teleseismic waves recorded by temporary broadband networks across Tibet show a north-dipping interface that begins 50 kilometers north of the Zangbo suture at the depth of the Moho (80 kilometers) and extends to a depth of 200 kilometers beneath the Bangong suture. Under northern Tibet a segmented south-dipping structure was imaged. These observations suggest a different form of detachment of the Indian and Asian lithospheric mantles caused by differences in their composition and buoyancy.

Journal Article↗
PubMed2026

Rumen DNA virome plasticity and viral metabolic potential are associated with seasonal adaptation in grazing yak and cattle on the Qinghai-Tibet Plateau.

BACKGROUND: As a diverse and abundant component of the rumen ecosystem, viruses interact with other microorganisms and are thought to influence microbial metabolism and host productivity. However, how the rumen virome responds to seasonal fluctuations in extreme environments remains poorly understood. Here, metagenomic analyses were used to investigate temporal dynamics of viral diversity, functional potential, and virus-host associations in the rumen virome of yak and cattle on the Qinghai-Tibet Plateau across warm and cold seasons. RESULTS: Rumen viral communities exhibited pronounced seasonal variation in both yaks and cattle, with higher alpha diversity observed during the cold season than in the warm season. Across seasons, the yak rumen virome showed greater alpha diversity and community stability than that of cattle. In total, 27,353 temperate and 31,976 virulent viral operational taxonomic units (vOTUs) were identified, predominantly belonging to the class Caudoviricetes. These viruses were linked to microbial hosts spanning 24 bacterial and 8 archaeal phyla, with Bacteroidota and Bacillota representing the dominant lineages. Virus-host associations were more numerous in the cold season and showed distinct host-specific patterns between yaks and cattle. Cold-season virome exhibited reduced diversity of anti-defense genes and enrichment of auxiliary metabolic genes (AMGs) associated with fatty acid metabolism and hemicellulose degradation. Notably, greater divergence between yaks and cattle was observed during the cold season: the yak rumen virome was enriched in pathways related to amino acid, lipid, and energy metabolism, as well as cellulose-degrading CAZyme families, whereas the cattle rumen virome showed enrichment in general carbohydrate metabolism and replication and repair processes. CONCLUSION: Seasonal plasticity of rumen DNA virome and pronounced interspecific divergence between yaks and cattle provide insight into their distinct microbial processes in the harsh environment of the Qinghai-Tibet Plateau. These findings suggest that the rumen DNA virome exhibits complex ecological and functional responses to seasonal variation and may be associated with host-microbiome interactions and nutrient utilization under environmental stress. This study highlights the ecological relevance of rumen viral genomes in understanding virus-microbiome interactions, microbial adaptation, and nutrient utilization in high-altitude ruminants.

Auxiliary metabolic genes↗
PubMed2026

First Isolation and Genomic Characterization of BVDV-1c in Przewalski's Gazelle (Procapra przewalskii) from the Qinghai-Tibet Plateau, China.

Przewalski's gazelle (Procapra przewalskii) is an endangered ungulate endemic to the Qinghai-Tibet Plateau of China. Increasing habitat alteration and close contact with domestic livestock have raised concerns about cross-species pathogen transmission, yet infectious disease studies in this species remain limited. To determine the etiology of illness in two deceased gazelles from a conservation facility in Qinghai Province, we screened samples for a panel of pathogens, including Mycoplasma ovipneumoniae, Clostridium perfringens toxin genes, Mannheimia haemolytica, Klebsiella pneumoniae, Mycoplasma capricolum subsp. capripneumoniae, Pasteurella multocida, Peste des petits ruminants virus (PPRV), Bovine viral diarrhea virus (BVDV), and Infectious bovine rhinotracheitis virus (IBRV), using PCR and RT-PCR. BVDV-specific nucleic acids were detected in tissue samples from both individuals, whereas all other targeted pathogens tested negative. The virus was successfully isolated in Madin-Darby Bovine Kidney (MDBK) cells and confirmed by RT-PCR, followed by whole-genome sequencing of the isolate, which was designated QH PSYL 2026. Phylogenetic analysis based on the full-length genome and 5'UTR sequences assigned the isolate to the BVDV-1c subgenotype. Notably, its 5'UTR sequence shared 100% identity with those of local cattle-derived BVDV strains, providing molecular evidence suggestive of an epidemiological linkage between wildlife and livestock. Integrating clinical signs, gross pathology, and laboratory results, the cases were consistent with BVDV infection as the primary presumptive etiology. To our knowledge, this is the first report of BVDV infection, virus isolation, and genomic characterization in Przewalski's gazelle. The detection of a BVDV-1c strain in this endangered species highlights the potential threat that livestock-associated pathogens pose to wildlife on the Qinghai-Tibet Plateau. These findings furnish crucial baseline data for disease surveillance, molecular epidemiology, and conservation management of Przewalski's gazelle and provide valuable scientific evidence for wildlife disease prevention and control in plateau ecosystems.

BVDV-1c↗