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1.
The copulatory pattern of groups of rats (Rattus norvegicus) was studied in the laboratory in a seminatural environment. In a given mating session, every oestrous female copulated with each male; likewise, every male copulated with each oestrous female. While individual males and females experienced similar amounts of copulation, there were dramatic sex differences in sequence and temporal pattern. Males mated in a multiple intromission pattern and had more ejaculatory series when several females were in oestrus. In contrast, females received intromissions and ejaculations in a random order, not in the sequence of a male ejaculatory series. Males copulated at shorter intervals than females did, a temporal sex difference that was determined by the pattern of female solicitations and male approaches. These sex differences are used to discuss the different units of analysis that are appropriate for male and female sexual behaviour in this species. Furthermore, the sex differences in the temporal pattern of copulation which emerged during group mating parallel the known sex differences in the temporal parameters of the neuroendocrine reflexes which mediate successful reproduction in the domestic strain.  相似文献   

2.
柑橘全爪螨种群空间格局的地学统计学分析   总被引:1,自引:1,他引:1  
应用地学统计学方法分析了柑橘园主要害螨柑橘全爪螨Panonychus citri(McGregor)种群的空间格局及其动态。结果表明,柑橘全爪螨种群具有空间相关性,变程介于1.10~21.0m,其半变异函数主要符合高斯模型,表现为聚集分布,其中3月、8月和9月的聚集强度较大;种群空间格局动态显示,4月、10月为该种群的两个发生高峰期,柑橘全爪螨种群数量快速上升扩散。地学统计学方法能够应用于柑橘全爪螨种群的空间格局分析,并有助于对该害螨进行发生预测与控制处理。  相似文献   

3.
Goal and Background  Geographical and technological differences in Life Cycle Inventory data are an important source for uncertainty in the result of Life Cycle Assessments. Knowledge on their impact on the result of an LCA is scarce, and also knowledge on how to manage them in an LCA case study. Objective  Goal of this paper is to explore these differences for municipal solid waste incinerator plants, and to develop recommendations for managing technological and geographical differences. Methodology  The paper provides a definition of technological and geographical differences, and analyses their possible impacts. In a case study, the differences are caused intentionally in ‘games’, by virtually transplanting incineration plants to a different location and by changing parameters such as the composition of the waste input incinerated. The games are performed by using a modular model for municipal solid waste incinerator plants. In each case, an LCA including an Impact Assessment is calculated to trace the impact of these changes, and the results are compared. Conclusions  The conclusions of the paper are two-fold: (1) reduce the differences in inventory data where their impact on the result is high; where it is possible reducing them to a great extent, and the effort for performing the change acceptable; in the case of incineration plants: Adapt the flue gas treatment, especially a possible DeNOx step, to the real conditions; (2) make use of modular process models that allow adapting plant parameters to better meet real conditions, but be aware of possible modelling errors. The paper invites the scientific community to validate the model used for a waste incinerator plant, and suggest putting up similar models for other processes, preferably those of similar relevance for Life Cycle Inventories.  相似文献   

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5.
Cotton is unusual among major crop plants in that two cross-fertile species are widely cultivated for a common economic product, fiber. Both historical evidence and classical genetic studies suggest that many improved forms of Gossypium barbadense (Sea Island, Egyptian, and Pima cottons) may include chromatin derived from G. hirsutum. Using 106 restriction fragment length polymorphism (RFLP) loci well distributed across the cotton genome, we revealed the amount and genomic distribution of G. hirsutum chromatin in 54 G. barbadense collections from around the world. The average G. barbadense collection was comprised of 8.9% alleles apparently derived from G. hirsutum. Pima cultivars (7.3 %) had fewer G. hirsutum alleles than Sea Island (9.0%) or Egyptian (9.6%) cultivars. G. hirsutum alleles were not randomly distributed, as 57.5% of the total introgression observed was accounted for by five specific chromosomal regions that span less than 10% of the genome. The average length of an introgressed chromosome segment was 12.9 cM. Overlap of introgressed chromatin in different breeding programs hints that retention of these G. hirsutum chromosomal segments may impart a selective advantage to G. barbadense genotypes. Although cluster analysis generally grouped germ plasm from common classes and/or breeding programs together, no 2 genotypes were identical — thus differences in the length and repertoire of introgressed chromosome segments also permit DNA fingerprinting of G. barbadense cultivars.  相似文献   

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7.
In the present study we investigated the genetic structure and genetic diversity of Pinus sylvestris populations in Bulgaria using chloroplast microsatellite markers and terpene analysis. We were interested in addressing the following questions: (1) can population structure in Scots pine be detected via chloroplast microsatellites markers and terpenes; (2) are there differences in population differentiation between the two analyses; and (3) how are the patterns related to geographic distances. Twelve provenances were chosen throughout the species' range in Bulgaria. Following DNA extraction, chloroplast microsatellite (cpSSR) loci were surveyed using six primer pairs. Between 4 to 8 size variants were identified at each locus. A total of 35 size variants at the six loci were identified, 11 occurring at low frequencies (<1%). They were combined in 134 different haplotypes, of which seven represent 1/3 of the genetic structure. AMOVA analysis revealed that 10.99% of the variation was found among populations, while 89.01% was expressed within populations. The cpSSR analysis divided Scots pine populations into two groups, the first represented by populations located in the south-western part of the Rhodopes and Pirin mountains, while the second group is located in the northeast of Rhodopes and Rila mountains. Terpene analysis revealed that on average, 53% of the monoterpene pool in P. sylvestris was accounted for by -pinene (range 47–59%) followed by β-pinene (range 6–12%). The presence of two distinct groups is weekly consistent with physical distances between populations, similar significant correlation between genetic distance determined by chloroplast microsatellites analysis and chemotype distance (determined by terpenes) was observed. Our results suggest that the structural pattern of genetic diversity of cpDNA in Scots pine populations is the consequence of historical biogeographic processes.  相似文献   

8.
Using a combination of electron-microscopic and immunocytochemical techniques the behaviour of the microtubular cytoskeleton has been followed throughout microsporogenesis in Lilium henryi Thunb. Cells treated with colchicine at specific stages and then permitted to develop to near maturity were used to investigate any participation by microtubules in the regulation of pollen wall patterning. The microtubular cytoskeleton assumes four principal forms during the meiotic process; in pre-meiosis it resembles that characteristic of meristematic somatic cells, during meiotic prophase it becomes associated with a nuclear envelope and, perhaps, with the chromosomes and, as the nuclear and cell divisions commence, it takes the form of a normal spindle apparatus. In the young microspores, microtubules assume a radial organisation extending from sites at the nuclear envelope to the inner face of the plasma membrane. No firm evidence was found linking any one of these forms of cytoskeleton with the generation of patterning on the cell surface. Experiments with colchicine revealed that the drug would readily dislocate the colpus, but did not affect the general reticulate patterning. The radial cytoskeleton was present during the deposition of the early primexine, but evidence from these and other studies (J.M. Sheldon and H.G. Dickinson 1983, J. Cell. Sci. 63, 191–208; H.G. Dickinson and J.M. Sheldon, 1984, Planta 161, 86–90) indicates patterning to be imprinted upon the plasma membrane prior to the appearance of this type of cytoskeleton. These results are discussed in terms of a recent model proposed to explain pattern generation on the surface of Lilium pollen grains, based on the self-assembly of patterning determinants within the plasma membrane.Abbreviation MTOC microtubule-organising centre  相似文献   

9.
Pinus nigra is a forest and low elevation mountain species found around the Mediterranean Sea that has had its distribution reduced and fragmented by anthropogenic disturbance. Due to commercial interest it is currently being replanted, however, the genetic structure of populations is little known and current planting strategies could threaten its genetic diversity. In the present study we investigated the genetic structure and genetic diversity of P. nigra populations in Bulgaria using chloroplast microsatellite markers and terpene analysis. Nine provenances were chosen throughout the species' range in Bulgaria. Following DNA extraction, chloroplast microsatellite (cpSSR) loci were surveyed using three primer pairs. Between 5 and 9 size variants were identified at each locus. A total of 22 size variants at the 3 loci were identified, that were combined in 68 different haplotypes, of which 7 represent 39.81% of the genetic structure. AMOVA analysis revealed that 6.06% of the variation was found among populations, while 93.94% was expressed within populations. The cpSSR analysis divided European Black pine populations into four groups, the first represented by populations located the eastern Rhodopes, Sr. Gora and St. Planina mountains, while the second group is primarily located in the Phodopes and Slavianca mountains. The populations from Pirin and Osogovo mountains show different genetic patterns. Terpene analysis revealed that most of the monoterpene pool in P. nigra was accounted for by α-pinene followed by β-pinene. The presence of four distinct terpene groups is not consistent with physical distances between populations, and a similar non-significant correlation between genetic distance determined by chloroplast microsatellites analysis and chemotype distance (determined by terpenes) was observed. Our results suggest that the structural pattern of genetic diversity of cpDNA in European Black pine populations is the consequence of historical biogeographic processes.  相似文献   

10.
Cyproterone acetate (CA), an antiandrogenic compound, was used in order to investigate the role of testosterone in bone growth processes. The formation of Haversian systems in the growing antlers of white-tailed deer (Odocoileus virginianus) were substantially affected by only 3.5 mg of CA kg/wk. The mineralization processes of the bone matrix were almost completely blocked and the antlers persisted in growing throughout the whole year. Plasma levels of thyroxine, alkaline phosphatase and GH were higher while cortisol and testosterone levels were lower than in controls. No differences were registered in plasma levels of Ca, P or urea nitrogen. Despite hypertrophy of interstitial tissue, spermatogenesis was almost completely blocked. The sexual behaviour and the body appearance of experimental animals was typical for castrates.  相似文献   

11.
Onion (Allium cepa L.) bulbs were frozen to −4 and −11 C and kept frozen for up to 12 days. After slow thawing, a 2.5-cm square from a bulb scale was transferred to 25 ml deionized H2O. After shaking for standard times, measurements were made on the effusate and on the effused cells. The results obtained were as follows.  相似文献   

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14.
Familial Mediterranean fever (FMF) is an autosomal, recessive disease, attributed to mutations in MEFV gene encoding pyrin, which is characterized by recurrent, acute and self-limiting attacks of fever as well as an increased neutrophil and monocyte apoptosis. Most disease-associated mutations in MEFV gene reside on the C-terminal PRYSPRY (B30.2) domain of pyrin, an area found to interact with the pro-apoptotic protein Siva. Because apoptotic events may be contributing to endogenous inflammation we hypothesized that mutations in pyrin may affect Siva-mediated apoptosis. The confirmation of this hypothesis would be of a great biological significance since it would be demonstrated a connection between apoptosis and inflammation. We used homology modeling to construct a 3-D model of Siva protein and the constructed model of Siva defined structural elements with potential of binding other proteins to induce apoptosis. Given that Siva protein binds pyrin as shown by transfection and immunoprecipitation experiments, apoptosis was assessed by FACS and Western blotting. No differences in rates of apoptosis in myeloid cells (THP-1) upon transfection with either wt pyrin or mutant forms of pyrin were found. Patients with FMF did not display any mutations in the Siva-1 (full length) gene. Siva-1 was not linked to pyrin in the major predicted FMF gene network constructed using a literature-curated gene signature for FMF. These results suggest that Siva-mediated unprovoked apoptosis is not likely to be involved in the pathogenesis of FMF.  相似文献   

15.
Nymphal colour/pattern polymorphisms are described in two cicadellid leafhopper species in the genus Eupteryx (Curt.). Eupteryx urticae (F.) exhibits three phenotypes (black, orange and white), while E. cyclops (Mats.) is polymorphic for pattern (ranging from completely pale to entirely black). There is no apparent parallel variation in the adults reared from these different phenotypes. The polymorphic variation reaches its full development in the last two nymphal instars, although it is possible to score earlier stages in certain cases. Crossing experiments revealed that part of the variation in E. urticae is controlled by a sex-linked gene, with orange dominant to black. Experiments with the white phenotype were inconclusive. In E. cyclops , the polymorphism is controlled by three genes, two autosomal and one sex-linked, each exhibiting complete dominance with epistatic interactions between them. A limited number of crosses between E. cyclops stock from Britain and Finland suggested that the loci controlling the polymorphism in the two countries are probably homologous. The theoretical implications of these findings are discussed.  相似文献   

16.
The physician and researcher must ultimately be able to combine qualitative and quantitative features from a variety of combinations of observations on data of many component items (i.e., many dimensions), and hence reach simple conclusions about interpretation, rational courses of action, and design. In the first paper of this series, it was noted that such needs are challenging the classical means of using statistics. Hence, the paper proposed the use of a Generalized Theory of Expected Information or "Zeta Theory". The conjoint event [a,b,c,..] is seen as a rule of association for a,b,c,.. associated with a rule strength I(a;b;c;...) = xi(s,o[a,b,c,..]) - xi (s,e[a,b,c,...]), where xi is the incomplete Zeta Function. Here, o[a,b,c,...] is the observed, and e[a,b,c,..] the expected, frequency of occurrence of conjoint event [a,b,c,...]. The present paper explores how output from this approach might be assembled in a form better suited for decision support. Related to this is the difficulty that the treatment of covariance and multivariance was previously rendered as a "fuzzy association" so that the output would fall into a similar form as the true associations, but this was a somewhat ad hoc approach in which only the final I( ) had any meaning. Users at clinical research sites had subsequently requested an alternative approach in which "effective frequencies" o[ ] and e[ ] calculated from the above variances and used to evaluate I( ) give some intuitive feeling analogous to the association treatment, and this is explored here. Though the present paper is theoretical, real examples are used to illustrate application. One clinical-genomic example illustrates experimental design by identifying data which is, or is not, statistically germane to the study. We also report on some impressions based on applying these techniques in studies of real, extensive patient record data which are now emerging, as well as on molecular design data originally studied in part to test the ability to deduce the effects of simple natural patient sequence variations ("SNPs") on patient protein activity. On the basis of these study experiences, methods of rationalizing and condensing the rules implied by associations and variances between data, as well as discussion of the difficulty of what is meant by "condensed", are presented in the Appendix.  相似文献   

17.
Steven M. Theg  Wolfgang Junge 《BBA》1983,723(2):294-307
Flash-induced pH changes inside thylakoids were measured with neutral red as an indicator in the presence and absence of low concentrations of uncouplers. We found that both carrier-type and pore-forming uncouplers caused the rapidly rising phase of the neutral red signal, previously attributed to proton deposition by water oxidation, to disappear. Gramicidin was particularly efficient in this respect, requiring only one molecule of uncoupler per 104 chlorophyll molecules to render the rapid proton deposition undectectable. This suggests that gramicidin did not act on each water-oxidizing enzyme individually, but rather at the level of the thylakoid membrane. In contrast to the effect on water-derived protons, the appearance of protons from plastoquinol was unaffected by gramicidin. Nor did gramicidin affect the rise of the neutral red signal due to proton deposition during two Photosystem I partial reactions with artificial donors. At the low gramicidin concentrations used, its effect on the neutral red signal could not be attributed to a general increase in proton permeability of the thylakoid membrane (acceleration of half decay from 9 to 0.8 s). The extent of alkalinization of the external medium during the first few hundred milliseconds following a light flash was unaltered by gramicidin, and we did not observe a kinetic correlation between the disappearance of the water proton and the decay of the transmembrane electric field. The last two findings suggest that the undetected protons had not crossed the thylakoid membrane, but instead were buffered away by some gramicidin-induced extra buffering power. pH titration of this extra buffering power revealed an apparent pK ranging between 7.2 and 7.7 and a stoichiometry of 2H+site. The rapid phase of the neutral red signal regained 90% of its original amplitude after seven flashes were applied at 6.7 Hz repetition rate to a sample containing gramicidin. This suggests limits to the extra buffering power. One possible interpretation of our experiments is the following: Protons derived from water oxidation are initially deposited into extended and highly buffering special domains, and only escape into the common internal phase when the buffering capacity of the domains is saturated. As an alternative one may consider that the thylakoid lumen is partitioned into at least two domains, each dominated by different photosystems and with slow proton equilibration between them. Either view requires internal subcompartmentation. The consequences of such subcompartmentation for chloroplast bioenergetics are still obscure.  相似文献   

18.
The primordial cord and the primitive, single and primordial islets present in the 3 earliest stages of the developing endocrine pancreas of sea bass were studied ultrastructurally. The primordial cord consisted of type I and II cells and was included in the gut. Besides these cell types, X cells were seen in the primitive islet. The single islet was made up of type I, II, III and IV cells. A correlation between these endocrine cell-types and cells previously identified immunocytochemically, was established. Type I, II, III and IV cells, correlated respectively with SST-25-, insulin-, SST-14- and glucagon-immunoreactive cells, and could be related to the D1, B, D2 and A cells, respectively, of older larvae and adult sea bass. Each cell type shows characteristic secretory granules from its first appearance. A progressive development of the organelles and an increase in the number and size of the secretory granules, whose ultrastructure also varied, was observed in the endocrine cells of the primordial cord and the succeeding islets. In 25-day-old larvae at the beginning of the fourth developmental stage, the primordial islet, the first ventral islet found, was close to a pancreatic duct and blood vessel, and consisted of type I and II cells whose ultrastructure was similar to that of the type I and II cells in the primordial cord. These data suggest a ductular origin for the pancreatic endocrine cells in the ventral pancreas. It is suggested that although endocrine cells undergo mitosis, their increase in number during the earliest development stages is principally due to the differentiation of surrounding cells.  相似文献   

19.
Wang X  Wang J  He S  Mayden RL 《Gene》2007,399(1):11-19
The complete mitochondrial genome sequence of the Chinese hook snout carp, Opsariichthys bidens, was newly determined using the long and accurate polymerase chain reaction method. The 16,611-nucleotide mitogenome contains 13 protein-coding genes, two rRNA genes (12S, 16S), 22 tRNA genes, and a noncoding control region. We use these data and homologous sequence data from multiple other ostariophysan fishes in a phylogenetic evaluation to test hypothesis pertaining to codon usage pattern of O. bidens mitochondrial protein genes as well as to re-examine the ostariophysan phylogeny. The mitochondrial genome of O. bidens reveals an alternative pattern of vertebrate mitochondrial evolution. For the mitochondrial protein genes of O. bidens, the most frequently used codon generally ends with either A or C, with C preferred over A for most fourfold degenerate codon families; the relative synonymous codon usage of G-ending codons is greatly elevated in all categories. The codon usage pattern of O. bidens mitochondrial protein genes is remarkably different from the general pattern found previously in the relatively closely related zebrafish and most other vertebrate mitochondria. Nucleotide bias at third codon positions is the main cause of codon bias in the mitochondrial protein genes of O. bidens, as it is biased particularly in favor of C over A. Bayesian analysis of 12 concatenated mitochondrial protein sequences for O. bidens and 46 other teleostean taxa supports the monophyly of Cypriniformes and Otophysi and results in a robust estimate of the otophysan phylogeny.  相似文献   

20.
The surfactant-degrading biocatalyst Pseudomonas C12B was immobilized by covalent linking on silanized inorganic supports and by physical entrapment of cells within reticulated polyurethane foam. Both immobilized biocatalysts have been shown to be appropriate for the effective primary biodegradation of the anionic surfactants sodium dodecyl sulphate (SDS), dodecylbenzene sulphonic acid (DBS), dioctyl sulphosuccinate (DOSS) and dihexyl sulphosuccinate (DHSS). The overall surfactant removal from water by cells entrapped in reticulated polyurethane foam exhibits a biphasic process, a rapid sorption step of the surfactant onto the cell-loaded support and the intrinsic primary biodegradation slower step, both acting cooperatively. The optimization of variables for the adsorption and the biodegradation processes (flow rate, particle size, substrate concentration) have been studied. Sorption isotherms for the surfactants on reticulated polyurethane foam have been established as type II of the Brunauer, Deming, Deming and Teller (BDDT) classification. The kinetics of the primary biodegradation of SDS by cells covalent linked on sepiolite treated with 3-aminopropyl triethoxysilane (APTS) were found to be first-order. In this case, surfactant adsorption does not exist.  相似文献   

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