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1.
Data from 24 craniofacial dimensions were compiled for samples representing all the human populations of the world. These were converted into C scores and used to construct Euclidean Distance dendrograms. The populations of the world are best depicted as 8 major regional clusters representing: Africa, Amerind, Asia-Mainland, Australo-Melanesia, Eskimo-Siberia, Europe, India, and Jomon-Pacific. The mainland Asian cluster divided into northern and southern components. The Neolithic in both areas is less clearly associated with the northern or southern components and may represent the form of their undifferentiated precursors. This needs to be tested by the addition of further specimens and an adequate sample from South China. Mongols are peripheral members of the Asia-Mainland cluster and should not be thought of as typifying the region as a whole. The use of the term "Mongoloid" is inappropriate in both theory and practice.  相似文献   

2.
A polyphasic PCR-DGGE approach was used to describe the microbial population occurring in natural whey cultures (NWCs) for water-buffalo Mozzarella cheese production. Total microbial community was assessed without cultivation by analyzing DNA directly extracted from the original samples of NWC. In addition, DNA extracted from bulks of cells formed by harvesting colonies from the serial dilution agar plates of a variety of culture media was used to profile the "cultivable" community. The 16S rDNA V3 region was amplified using DNA from NWC as well as DNA from bulks as templates and the amplicons were separated by DGGE. The microbial entities occurring in NWCs were identified by partial 16S rDNA sequencing of DGGE bands: four lactic acid bacteria (LAB) closest relative of Streptococcus thermophilus, Lactococcus lactis, Lactobacillus delbrueckii and Lactobacillus crispatus were revealed by the analysis of DNA directly extracted from NWC while two other LAB, Lactobacillus fermentum and Enterococcus faecalis, were identified by analyzing DNA from the cultivable community. The developed PCR-DGGE analysis of the "cultivable" community showed good potential in evaluating microbial diversity of a dairy environment: it usefully highlighted the bias introduced by selective amplification when compared to the analysis of the total community from NWC and allowed suitability of media and growth conditions to be evaluated. Moreover, it could be used to complete the culture independent study of microbial diversity to give information on concentration ratios among species occurring in a particular environment and can be proposed for rapid identification of dominant microorganisms in alternative to traditional tools.  相似文献   

3.
Relationships between lengths of long bones in early medieval Alamanns and in recent white Americans do not differ significantly. Lacking evidence of any differences between the contribution of trunk length to stature in the two samples, formulas for estimating stature based on relationships of bone lengths to stature in an American sample thus appear applicable to the Alamannic material.  相似文献   

4.
Body shape differences between two benthophagous, sympatric cichlid species, Ctenopharynx pictus and Otopharynx sp. “heterodon nankhumba” were examined for 14 morphometric characters using measurements obtained from 11 morphological landmarks and additional 6 characters from the head region using principal component and regression analyses. The two species, though not closely related, superficially resemble each other and, being benthic feeders, directly compete for food resources unless morphological differences lead to trophic specialization. Hence, the present study explores the presence of such morphological variations. Principal component analysis (PCA), revealed that only four characters loaded highly on PC II and, therefore, account for most of the variations in the external morphology between the two species. C. pictus has longer lower jaws reflecting longer gape, and a shorter abdominal cavity than O. sp. “heterodon nakhumba”. The regression analyses showed significant differences in the allometric coefficients of the lower jaw and abdominal cavity, which might have contributed to differences in overall shape detected between the two species. The difference in gape size between the two species may be related to different feeding habits employed by each species, and such specializations are suggested to reduce interspecific competition for food resources. We suggest that the ensuing ecological separation promotes sympatry of these two species.  相似文献   

5.
Historical and anthropological data suggest that skeletons excavated from an 11th to 15th century mass grave in Bondy, France, may be those of victims of the Great Plague. Using high-throughput real-time PCR investigation of the dental pulp collected from 14 teeth from five such skeletons, we detected Bartonella quintana DNA in three individuals and Yersinia pestis DNA in two individuals. DNA from five other deadly pathogens was not found. Suicide PCR genotyping confirmed Y. pestis DNA belonging to the Orientalis biotype. One individual had co-infection. These data suggest a plague epidemic in a population already infected by the body louse-transmitted B. quintana or a body louse-driven transmission of the plague that drove a medieval epidemic in inland Europe.  相似文献   

6.
Social structure, limited dispersal, and spatial heterogeneity in resources are ubiquitous in wild vertebrate populations. As a result, relatives share environments as well as genes, and environmental and genetic sources of similarity between individuals are potentially confounded. Quantitative genetic studies in the wild therefore typically account for easily captured shared environmental effects (e.g., parent, nest, or region). Fine-scale spatial effects are likely to be just as important in wild vertebrates, but have been largely ignored. We used data from wild red deer to build "animal models" to estimate additive genetic variance and heritability in four female traits (spring and rut home range size, offspring birth weight, and lifetime breeding success). We then, separately, incorporated spatial autocorrelation and a matrix of home range overlap into these models to estimate the effect of location or shared habitat on phenotypic variation. These terms explained a substantial amount of variation in all traits and their inclusion resulted in reductions in heritability estimates, up to an order of magnitude up for home range size. Our results highlight the potential of multiple covariance matrices to dissect environmental, social, and genetic contributions to phenotypic variation, and the importance of considering fine-scale spatial processes in quantitative genetic studies.  相似文献   

7.
M.J. Bibb  P.R. Findlay  M.W. Johnson   《Gene》1984,30(1-3):157-166
Bacterial genes that code for proteins appear to possess a codon usage characteristic of their overall base composition. This results in different but predictable non-random distributions of nucleotides within codons, permitting the recognition of protein-coding sequences in a wide range of bacterial species. The nature of this distribution depends on the base composition of the coding sequence. The position-specific differences are especially conspicuous in genes of extreme G + C content, allowing the particularly reliable prediction of the reading frame and coding strand of experimentally determined DNA sequences. This fmding has been exploited to identify the coding sequence of the viomycin phosphotransferase (vph) gene of Streptomyces vinaceus. An easily applied computer program (“Frame”) has been written to carry out and display such analyses.  相似文献   

8.
SYNOPSIS. A defined medium for an insect trypanosomatid, “Leptomonas pessoai” (probably a member of the genus Herpetomonas) isolated from the reduviid Zelus leucogrammus, allows growth up to 37 C. No marked differences were evident for growth at 37 C. The requirements for amino acids, vitamins, purine, and hemin, and pH range were like those established for Crithidia fasciculata. Again like C. fasciculata, it remains alive at 4 C for at least 3 months in a çlycerolated defined medium.  相似文献   

9.
Nine healthy subjects have been studied while exposed to the normal alternation of light and dark, but with their sleep and activity pattern adjusted to a 27-h “day” for 17 imposed “days.” Rectal temperature showed clearly the competing influences of 27-h and 24-h components, and these were separated by the method of “purification.” The method indicated that the endogenous component had a constant amplitude throughout the experiment and remained entrained to solar (24-h) time; by contrast, the exogenous component followed the imposed 27-h “day” and increased rectal temperature in proportion to the amount of subjects' activity. Wrist movement was used to assess activity while in bed (attempting sleep) and out of bed (when naps were forbidden). While these results confirmed adherence of the subjects to the imposed 27-h “days,” they also showed that the dichotomy between “out of bed” activity and “in bed” inactivity depended on the phase relationship between endogenous (24h) and exogenous (27h) components. Thus, the dichotomy was highest and was equal to that during control days (with a conventional 24-h life-style) when the two components were in phase and lowest when the solar and imposed day were in antiphase. This was due to changes in activity, both during time spent in bed and out of bed.

We confirm that this protocol can produce valuable information about the properties of the circadian system in humans and the value of the process of purification of temperature data. We have established also that the very simple and noninvasive measurement of wrist movement, coupled with its use to calculate dichotomy indices, provides valuable information that both confirms and extends the results obtained from the more conventional (butalso more invasive) measurement of rectal temperature.  相似文献   

10.
Curves of transitions in double (2-->1 transition) and triple (3-->2 transition) complexes of oligonucleotides dA(N1)with dT(N2) in solutions with Na(+) and Mg(2+) are calculated for the case of oligomer lengths from 10 to 500 nucleotides in the wide range of ion concentrations. The calculated curves of transitions and their differential analogs reflect rather exactly the position and form of experimental curves and describe dependences of transition temperatures on the length of molecules, their concentration, and ionic conditions. Values of the nucleation parameter beta for the systems studied are determined by comparison of the calculated and experimental data obtained in a number of works. The average beta value equal to 10(-3) l/mole is in an agreement with values reported for similar systems earlier. It is shown that disordering of duplex and triplex ends ("end fraying") has an essential influence on the form of melting curves, their asymmetry and the increase of the transition interval.  相似文献   

11.
As circumstances of conquest change, leaders of empires must adapt their colonial strategies in order to be successful. One example of such modification in approach is the shift from Middle Kingdom to New Kingdom Egyptian colonial activities in Nubia. During the Middle Kingdom (2050-1650 BC) Egypt used aggressive military campaigns to subdue the strong Nubian polity at Kerma, resulting in the construction of fortresses and many victory stelae. In the subsequent New Kingdom period (1550-1050 BC) during which the Egyptian administration succeeded in occupying nearly all of Nubia, changes were necessary in conquest strategies. Diplomacy and cooperation may have replaced military action as mechanisms of control. This article investigates changes in imperial policy through the examination of traumatic injuries in human skeletal remains. Patterns of injuries in a sample from the site of Tombos, an Egyptian colonial cemetery in Nubia dating to the New Kingdom period, are compared with data on the patterns of injuries from Kerma, a cemetery dating to the Middle Kingdom period, published by Judd (2004). Analysis indicates a decrease in the level of traumatic injuries from Kerma to Tombos supporting the idea that through time the Egyptian administration modified their colonial strategy toward more nonviolent means. This article presents data on differences in the patterns of injury at Tombos and Kerma and explores possible explanations for this variation.  相似文献   

12.
The proximate composition, nutrient and trace elements of the planktonic algal “jellies” of Lake Oguta in Southern Nigeria, are provided as guides to their utilization and control, using flood (rainy) and dry season samples. These “jellies” are an unusual, macroscopic planktonic algal community in the lake, made up mostly of blue-green algae (Microcystis, Anabaena, Chroococcus) with some green algae (e. g. Spirogyra) and pennate diatoms (e.g. Navicula) rather epiphytic on the mucous jellies of the blue-green algae. Water content was high (98.2% mean, range 97.5-99.5%). Ash, protein and fat had values of 41.7 (39.0-46.2%), 16.9 (15.6-19.4%), and 2.0 (1.7-2.1%) respectively. Crude fibre and carbohydrates were high (25.8% and 12.4%). The levels of phosphorus and nitrogen were rather high, so were the major cations whose order of dominance (Ca > K > Mg > Na) differed from that of the lake water. Macronutrients increased in their concentrations during the rainy flood season while the reverse was the case with the micronutrients. Diagenesis of the endogenic minerals rather than anthropogenic factors are thought to be the reason for the seasonal changes in the ionic concentrations. Possible uses of the algal jellies are discussed as well as their control options.  相似文献   

13.
The phylogeny of the New Zealand hepialid moths was estimated from a 527-bp nucleotide sequence from the mitochondrial DNA cytochrome oxidase subunit I and II gene regions. New haplotypes were identified for Wiseana cervinata, W. copularis, and W. signata. Phylogenetic reconstructions using maximum parsimony and maximum likelihood methods indicated that the four hepialid lineages Aenetus, Aoraia, "Oxycanus" Cladoxycanus, and "Oxycanus" s. str. hypothesized by Dugdale (1994) based on a morphological taxonomic revision were monophyletic within New Zealand. Addition of exemplars from the Australian genera Fraus, Jeana, Oxycanus, and Trictena to the data set tentatively support the monophyly of the New Zealand "Oxycanus" lineages. Estimated times of divergence for the genus Wiseana taxa fitted well with known geological events and suggest that the genus may have diverged 1-1.5 mya.  相似文献   

14.
In most populations of the “strumarium” morphological complex of Xanthium strumarium L. (sensu lato) in northern Europe and in India, a new compound, xanthinosin, is the only detectable sesquiterpene lactone. In populations of this morphological complex in Portugal and Egypt as well as in eastern Asia, USSR, Korea, Hong Kong and Taiwan, xanthinin and xanthatin occur as major constituents along with xanthinosin. Experimental F, hybrids between pistillate Indian plants which contained only xanthinosin and staminate plants from Hong Kong which contained a mixture of xanthinin, xanthatin and xanthinosin produced a mixture of compounds in which the percentage of xanthinin increased relative to its percentage in the Hong Kong parent. The sesquiterpenoid data suggest that the various taxa in the “strumarium” morphological complex can be divided into three groups: (a) X. strumarium (sensu stricto) and X. indicum König, containing primarily or exclusively xanthinosin; (b) X. sibiricum Patrin and X. brasilicum Vell., with xanthinin and xanthinosin predominating; and (c) X. inaequilaterum DC., with almost equal proportions of xanthinin, xanthatin and xanthinosin. Two other taxa of the complex. X. japonicum Widd. and X. abyssinicum Wallr., were not available for inclusion in the present study.  相似文献   

15.
Nine species of insects from three different geographical regions of Canada were examined for freezing tolerance, supercooling capacity, water content and changes in biochemical characteristics during acclimation to subzero temperatures. Six species proved to be freezing tolerant, the remaining three freezing susceptible. The majority of species in each category conformed to the generally recognized profiles of overwintering response. There were enough specific variations within each category, however, to indicate that cold tolerance mechanisms have evolved independently on a number of different occassions. Specific physiological and biochemical anomalies in these insects were discussed.  相似文献   

16.
Helen E. Raybould   《Peptides》1991,12(6):1279-1283
The role of vagal afferent pathways and cholecystokinin (CCK) in mediating changes in gastric motor function after a meal was investigated in urethane-anesthetized rats. Proximal gastric motor function was measured manometrically, and nutrients were infused into an isolated segment of duodenum. Inhibition of gastric motility in response to duodenal infusion of protein (peptone or casein), but not carbohydrate (glucose), was significantly attenuated by administration of the CCK antagonist, L364,718. Selective ablation of vagal afferents by perineural treatment with the sensory neurotoxin, capsaicin, significantly reduced responses to both duodenal protein and glucose. These results suggest that protein in the duodenum decreases proximal gastric motor function via release of CCK and a vagal capsaicin-sensitive afferent pathway. In contrast, glucose acts via a capsaicin-sensitive vagal pathway not involving CCK. Thus separate neural and hormonal mechanisms mediate the effects of different nutrients in the duodenal feedback regulation of gastric motor function.  相似文献   

17.
The influence of near null magnetic field on in vitro growth of different cultures of potato and related Solanum species was investigated for various exposure times and dates. Potato (Solanum tuberosum L. cv. Désirée) in vitro cultures of shoot tips or nodal segments were used. Three different exposure periods revealed either stimulation or inhibition of root, stem, or leaf in vitro growth after 14 or 28 days of exposure. In one experiment the significant stimulation of leaf growth was also demonstrated at biochemical level, the quantity of chlorophyll a and b and carotenoids increasing more than two-fold. For the wild species Solanum chacoense, S. microdontum, and S. verrucosum, standardized in vitro cultures of nodal stem segments were used. Root and stem growth was either stimulated or slightly inhibited after 9 days exposure to near null magnetic field. Callus cultures obtained from potato dihaploid line 120/19 were maintained in near null magnetic field in 2 different months. For these experiments as well as for Solanum verrucosum, callus cultures recorded either slight inhibition or no effect on fresh weight. For all experiments significant growth variation was brought about only when geomagnetic activity (AP index) showed variations at the beginning of in vitro growth and when the explant had at least one meristematic tissue. Moreover longer maintenance in near null magnetic field, 28 days as compared to 14 days or the controls, can also make a difference in plant growth in response to geomagnetic field variations when static component was reduced to zero value. These results of in vitro plant growth stimulation by variable component of geomagnetic field also sustain the so-called seasonal "window" effect.  相似文献   

18.
Skeletal muscle cells (fibers) contract by shortening their parallel subunits, the myofibrils. Here we show a novel pattern of myofibril orientation in white muscle fibers of large black sea bass, Centropristis striata. Up to 48% of the white fibers in fish >1168 g had peripheral myofibrils undergoing an ~90o shift in orientation. The resultant ring band wrapped the middle of the muscle fibers and was easily detected with polarized light microscopy. Transmission electron microscopy showed that the reoriented myofibrils shared the cytoplasm with the central longitudinal myofibrils. A microtubule network seen throughout the fibers surrounded nuclei but was mostly parallel to the long‐axis of the myofibrils. In the ring band portion of the fibers the microtubule cytoskeleton also shifted orientation. Sarcolemmal staining with anti‐synapsin was the same in fibers with or without ring bands, suggesting that fibers with ring bands have normal innervation and contractile function. The ring bands appear to be related to body‐mass or age, not fiber size, and also vary along the body, being more frequent at the midpoint of the anteroposterior axis. Similar structures have been reported in different taxa and appear to be associated with hypercontraction of fibers not attached to a rigid structure (bone) or with fibers with unusually weak links between the sarcolemma and cytoskeleton, as in muscular dystrophy. Fish muscle fibers are attached to myosepta, which are flexible and may allow for fibers to hypercontract and thus form ring bands. The consequences of such a ring band pattern might be to restrict the further expansion of the sarcolemma and protect it from further mechanical stress. J. Morphol., 2012. © 2012 Wiley Periodicals, Inc.  相似文献   

19.
The true diversity and interspecific limits in the Neotropical endemic avian genus Dendrocolaptes (Furnariidae) remain a highly controversial subject, with previous genus‐wide assessments, based mostly on morphological characters, producing poorly resolved phylogenies. The lack of well‐resolved, robust, and taxonomically densely sampled phylogenies for Dendrocolaptes prevents reliable inferences on the genus’ actual species diversity and evolutionary history. Here, we analyzed 2,741 base pairs of mitochondrial and nuclear genes from 43 specimens belonging to all species and the majority of subspecies described for Dendrocolaptes to evaluate species limits and reconstruct its diversification through time. Our phylogenies recovered a monophyletic Dendrocolaptes, with two main highly supported internal clades corresponding to the D. certhia and D. picumnus species complexes. Also, our analyses supported the monophyly of most Dendrocolaptes species recognized today, except D. picumnus, which was consistently recovered as paraphyletic with respect to D. hoffmannsi. A coalescent‐based test supported a total of 15 different lineages in Dendrocolaptes and indicated that the number of currently accepted species within the genus may be greatly underestimated. Particularly relevant, when combined with previous analyses based on plumage characters, comparative high levels of genetic differentiation and coalescent analyses support the recognition of D. picumnus transfasciatus as a full species that is already under threat. Ancestral area reconstructions suggest that diversification in Dendrocolaptes was centered in lowland Amazonia, with several independent dispersal events leading to differentiation into different adjacent dry and high elevation forest types throughout the Neotropics, mainly during the Middle and Late Pleistocene.  相似文献   

20.
2019年底暴发并席卷全球的新型冠状病毒肺炎疫情已经成为需要世界各国共同努力克服的全球重大卫生安全挑战。当前,中国已基本控制国内新冠肺炎疫情,并在疫情相关科学研究及公共卫生产品研发方面取得重大进展,同时加强了与“一带一路”参与国家开展国际科技合作。对中国与“一带一路”参与国家抗击新冠肺炎疫情的基础研究合作、国际科技合作项目等方面进行梳理,可以看到:中国与“一带一路”参与国家形成了领域交叉、节点多样的复杂合作网络,并主要与东南亚、中东欧和西亚各国合作密切;中国与“一带一路”参与国家的科研机构已在防控、流行病学和治疗等领域展开了大量实质研究,合作关系更偏向援助型合作。未来应加强与“一带一路”参与国家的生物技术产业合作与技术转移,发挥“一带一路”区域支点国家的示范效应等方面构建与“一带一路”参与国家更丰富、紧密、务实的科技合作关系。  相似文献   

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