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Ferdane Kutlar Jose M. Gonzalez-Redondo Abdullah Kutlar Aytemiz Gurgey Çigdem Altay Georgi D. Efremov Klara Kleman Titus H. J. Huisman 《Human genetics》1989,82(2):179-186
Summary Details are given of a study of blood samples from 24 patients with Hb H disease from different Mediterranean countries and from the Far East. Four different types of -thal-1 (--) were observed, namely-() ( 20.5-kb deletion);--MED-I ( 17.5-kb deletion);--MED-II (>26.5-kb deletion); and--SEA ( 18-kb deletion, in Orientals only). The -thal-2 was mainly of the deletion type (16 with the 3.7-kb deletion; 1 with the 4.2-kb deletion), while 4 of the 7 patients with a nondeletional type had the five-nucleotide deletion at the donor splice site of the first intron of the 2 gene. All patients had a mild-to-moderate hemolytic anemia; no significant differences in hematology were observed between the groups. Hb A2 was decreased to about one-third of the normal level. The Hb H formation varied considerably and its quantitation was not always satisfactory. Patients with Hb H disease due to any -thal-1 combined with a nondeletional -thal-2 had the highest Hb H levels and a more marked anemia. The chain production was small and absent in patients with the MED-II type of -thal-1 because this deletion included the and genes. The highest chain levels were present in the four patients with the SEA type of -thal-1. The chain production was increased, particularly in patients with a mutation of C T at position-158 to the G globin gene. This chain was primarily present as Hb Bart's (or 4) and only about 15% was recovered as Hb F or 22. The evaluation of the rate of chains produced in these patients was greatly facilitated by data from one patient who had Hb H disease and a heterozygosity for the A-+. The low levels of Hb A2 and of Hb F (relative to Hb Bart's) can be explained by a decreased affinity of chains for and chains as compared with chains in conditions of severe chain deficiency. 相似文献
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To isolate potential insect biocontrol agents, entomogenous nematodes were surveyed in Tennessee plant nurseries in 1991. Soil samples from 113 nursery sites were baited with greater wax moth (Galleria mellonella) larvae, house cricket (Acheta domesticus) adults, lesser mealworm (Alphitobius diaperings) adults, and house fly (Musca domestica) larvae. Heterorhabditis bacteriophora and Steinernema carpocapsae were each recovered from 17 soil samples. Heterorhabditis bacteriophora was more common in habitats with crape myrtle (Lagerstroemia indica) and Chinese juniper (Juniperus chinensis) than other nursery plants, and S. carpocapsae was more frequently recovered from habitats with juniper and Southern magnolia (Magnolia grandiflora). Bulk density, electrical conductivity, organic matter, pH, temperature, and moisture content of the entomogenous-nematode positive soil samples were compared. Other nematode genera recovered with insect baits included Rhabditis sp., Pelodera sp., Cryptaphelenchoides sp., and Mesodiplogaster sp., which was recovered from a greater percentage of soil samples than the other five genera. 相似文献
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Dimiter S. Dimitrov Georgi A. Georgiev Natalia G. Stoicheva Trayko T. Traykov 《Journal of theoretical biology》1982,96(4):517-532
Double-valued pressure-volume relationships in dynamic conditions for spherical membranes, modelling the lung alveoli, were obtained at small deformations. This hysteretic behavior was considered to be produced by at least three independent mechanisms: (1) the lung parenchyma exhibits viscoelastic properties; (2) the lung surface film, independent of the tissue, exhibits viscoelastic properties and (3) the pressure acting on the inner membrane surface depends on the rate of the alveolus volume change, due to the air viscous resistance in the bronchial tree. In each case, the maximum volume change, the hysteresis loop area, the tilt angle of the hysteresis loop and the relaxation time of the system were calculated. The results show pronounced hysteresis at normal breathing due to the air viscous resistance and smaller one due to the tissue and surface viscoelastic properties. In quasistatic conditions the values of the surface viscoelasticity and the tissue viscoelasticity effects are comparable or different, depending on the concrete external conditions. Comparison with the available experimental data is discussed in detail. 相似文献
6.
Georgi Z. Genchev Morten Källberg Gamze Gürsoy Anuradha Mittal Lalit Dubey Ognjen Perisic Gang Feng Robert Langlois Hui Lu 《Cell biochemistry and biophysics》2009,55(3):141-152
Efficient communication between the cell and its external environment is of the utmost importance to the function of multicellular
organisms. While signaling events can be generally characterized as information exchange by means of controlled energy conversion,
research efforts have hitherto mainly been concerned with mechanisms involving chemical and electrical energy transfer. Here,
we review recent computational efforts addressing the function of mechanical force in signal transduction. Specifically, we
focus on the role of steered molecular dynamics (SMD) simulations in providing details at the atomic level on a group of protein
domains, which play a fundamental role in signal exchange by responding properly to mechanical strain. We start by giving
a brief introduction to the SMD technique and general properties of mechanically stable protein folds, followed by specific
examples illustrating three general regimes of signal transfer utilizing mechanical energy: purely mechanical, mechanical
to chemical, and chemical to mechanical. Whenever possible the physiological importance of the example at hand is stressed
to highlight the diversity of the processes in which mechanical signaling plays a key role. We also provide an overview of
future challenges and perspectives for this rapidly developing field. 相似文献
7.
Rodriguez-Kern A Gegelashvili M Schousboe A Zhang J Sung L Gegelashvili G 《Neurochemistry international》2003,43(4-5):363-370
8.
Chandana Basu Mallick Florin Mircea Iliescu M?rt M?ls Sarah Hill Rakesh Tamang Gyaneshwer Chaubey Rie Goto Simon Y. W. Ho Irene Gallego Romero Federica Crivellaro Georgi Hudjashov Niraj Rai Mait Metspalu C. G. Nicholas Mascie-Taylor Ramasamy Pitchappan Lalji Singh Marta Mirazon-Lahr Kumarasamy Thangaraj Richard Villems Toomas Kivisild 《PLoS genetics》2013,9(11)
Skin pigmentation is one of the most variable phenotypic traits in humans. A non-synonymous substitution (rs1426654) in the third exon of SLC24A5 accounts for lighter skin in Europeans but not in East Asians. A previous genome-wide association study carried out in a heterogeneous sample of UK immigrants of South Asian descent suggested that this gene also contributes significantly to skin pigmentation variation among South Asians. In the present study, we have quantitatively assessed skin pigmentation for a largely homogeneous cohort of 1228 individuals from the Southern region of the Indian subcontinent. Our data confirm significant association of rs1426654 SNP with skin pigmentation, explaining about 27% of total phenotypic variation in the cohort studied. Our extensive survey of the polymorphism in 1573 individuals from 54 ethnic populations across the Indian subcontinent reveals wide presence of the derived-A allele, although the frequencies vary substantially among populations. We also show that the geospatial pattern of this allele is complex, but most importantly, reflects strong influence of language, geography and demographic history of the populations. Sequencing 11.74 kb of SLC24A5 in 95 individuals worldwide reveals that the rs1426654-A alleles in South Asian and West Eurasian populations are monophyletic and occur on the background of a common haplotype that is characterized by low genetic diversity. We date the coalescence of the light skin associated allele at 22–28 KYA. Both our sequence and genome-wide genotype data confirm that this gene has been a target for positive selection among Europeans. However, the latter also shows additional evidence of selection in populations of the Middle East, Central Asia, Pakistan and North India but not in South India. 相似文献
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Konstantina V. Kocheva Peter I. Petrov Georgi I. Georgiev 《Central European Journal of Biology》2013,8(5):499-503
Hydroponically grown wheat seedlings of two prominent Bulgarian cultivars (Katya and Prelom) were subjected to 48 h osmotic stress with PEG 8000 and were then rehydrated. The degree of stress was evaluated by monitoring relative water content, lipid peroxidation level, and accumulation of free proline and hydrogen peroxide in the leaves. Anatomy and ultrastructure of leaf tissue were observed under light microscopy. After imposition of stress, drought tolerant cultivar Katya displayed higher free proline content and significantly lower malondialdehyde and peroxide concentration in leaves than in the leaves of susceptible cultivar Prelom. After 24 h of rehydration Katya showed better ability to restore leaf water status and an apparent tendency towards recovery, whereas Prelom sustained higher levels of hydrogen peroxide, lipid peroxidation products and free proline and markedly low relative water content. Here, we have uncovered some of the characteristics displayed by cultivar Katya that enable it to survive and recover from severe osmotic stress. Interestingly, there was congruence between our results and the high level of cultivar Katya drought tolerance observed in the field. 相似文献
10.
Meredith?L. Carpenter Jason?D. Buenrostro Cristina Valdiosera Hannes Schroeder Morten?E. Allentoft Martin Sikora Morten Rasmussen Simon Gravel Sonia Guillén Georgi Nekhrizov Krasimir Leshtakov Diana Dimitrova Nikola Theodossiev Davide Pettener Donata Luiselli Karla Sandoval Andrés Moreno-Estrada Yingrui Li Jun Wang M.?Thomas?P. Gilbert Eske Willerslev William?J. Greenleaf Carlos?D. Bustamante 《American journal of human genetics》2013,93(5):852-864
Most ancient specimens contain very low levels of endogenous DNA, precluding the shotgun sequencing of many interesting samples because of cost. Ancient DNA (aDNA) libraries often contain <1% endogenous DNA, with the majority of sequencing capacity taken up by environmental DNA. Here we present a capture-based method for enriching the endogenous component of aDNA sequencing libraries. By using biotinylated RNA baits transcribed from genomic DNA libraries, we are able to capture DNA fragments from across the human genome. We demonstrate this method on libraries created from four Iron Age and Bronze Age human teeth from Bulgaria, as well as bone samples from seven Peruvian mummies and a Bronze Age hair sample from Denmark. Prior to capture, shotgun sequencing of these libraries yielded an average of 1.2% of reads mapping to the human genome (including duplicates). After capture, this fraction increased substantially, with up to 59% of reads mapped to human and enrichment ranging from 6- to 159-fold. Furthermore, we maintained coverage of the majority of regions sequenced in the precapture library. Intersection with the 1000 Genomes Project reference panel yielded an average of 50,723 SNPs (range 3,062–147,243) for the postcapture libraries sequenced with 1 million reads, compared with 13,280 SNPs (range 217–73,266) for the precapture libraries, increasing resolution in population genetic analyses. Our whole-genome capture approach makes it less costly to sequence aDNA from specimens containing very low levels of endogenous DNA, enabling the analysis of larger numbers of samples. 相似文献