共查询到20条相似文献,搜索用时 21 毫秒
1.
2.
Marian Y.L. Wong 《Ethology : formerly Zeitschrift fur Tierpsychologie》2011,117(7):638-644
The number of group members in an animal society can have a major influence on group members’ life history, survival, and reproductive success. Identifying the factors that limit group size is therefore fundamental for a complete understanding of social behavior. Here, I examined the relationships between resource availability, social conflict, and group size in the coral‐dwelling fish, Paragobiogon xanthosomus (Gobiidae). The size of the largest (breeding) female and the minimum size difference required for hierarchy stability strongly but not perfectly predicted maximum group size, suggesting that social conflicts and hierarchy structure set the upper limit on group size. Deviations in group size around the predicted maximum were explained by variation in average body size ratios but not by variation in coral size, suggesting that coral size does not directly influence group size. In contrast, coral size was a significant predictor of body size ratios, and possible explanations for this relationship are discussed. Group size may be limited by the social conflicts that characterize size‐based dominance hierarchies. Ecological factors, namely coral size, may in turn play an indirect role via an effect on body size ratios. 相似文献
3.
S. Irvine S. Arumuganathar J. R. McEwan S. N. Jayasinghe 《Engineering in Life Science》2007,7(6):599-610
In this paper, a coaxial jetting methodology is demonstrated as a first example (non‐electric field driven) completely run by aerodynamic forces which are brought about by the application of a differential pressure for the safe handling of primary living organisms by means of jets as encapsulated droplets. Previously this jetting technique in this configuration has only been investigated for processing combinations of liquid‐liquid and liquid‐gas systems. These developmental studies into aerodynamically assisted jets (AAJ) have unearthed a versatile bio‐jetting approach referred to here as coaxial aerodynamically assisted bio‐jetting (CAABJ). In the current work, this flexible approach is demonstrated to handle two primary cell types for drop‐and‐placing onto several different substrates. Furthermore, the study assesses cellular viability of the post‐treated cells in comparison to controls by way of flow cytometry. These first steps demonstrate the promise this protocol has in exploring the creation of biologically viable structures to form encapsulations of cells which would be useful as a direct tissue engineering to the immuno‐hinding methodology in bio‐repair and therapeutics. Therefore, these investigations place CAABJ into the cell jetting pursuit together with bio‐electrosprays, which will undergo an explosive developmental research. 相似文献
4.
Yvonne Piotrowski Guido Hansen A. Linda Boomaars‐van der Zanden Eric J. Snijder Alexander E. Gorbalenya Rolf Hilgenfeld 《Protein science : a publication of the Protein Society》2009,18(1):6-16
The polyproteins of coronaviruses are cleaved by viral proteases into at least 15 nonstructural proteins (Nsps). Consisting of five domains, Nsp3 is the largest of these (180–210 kDa). Among these domains, the so‐called X‐domain is believed to act as ADP‐ribose‐1″‐phosphate phosphatase or to bind poly(ADP‐ribose). However, here we show that the X‐domain of Infectious Bronchitis Virus (strain Beaudette), a Group‐3 coronavirus, fails to bind ADP‐ribose. This is explained on the basis of the crystal structure of the protein, determined at two different pH values. For comparison, we also describe the crystal structure of the homologous X‐domain from Human Coronavirus 229E, a Group‐1 coronavirus, which does bind ADP‐ribose. 相似文献
5.
Proposed in this paper is a quantitative method which can be effectively used for
measuring karyotype asymmetry of chromosome complements. As well known, karyotype
symmetry of a complement is determined by arm ratios and relative lengths. We define the
karyotype as a theoretical symmetrical karyotype in which all chromosome ann ratios are 1
and all chromosomes are equal in length. An observed complement can be assumed to have a
corresponding theoretical symmetrical karyotype, and different complements with the same
ploidy and the same basic number share a common theoretical symmetrical karyotype. Therefore, to measure the karyotype asymmetry of an observed complement only requires determining the differences in both arm ratios and relative lengths between the observed karyotype
and its corresponding theoretical symmetrical karyotype.
Based on this idea, and employing absolute value distance to measure the difference in
symmetry two formulas for measuring asymmetry respectively in arm ratio and relative
length are developed as follows:
Here r is arm ratio (long / short); Lis relative length (long+short); k is ploidy; x is basic
chromosome number; m is the number of homologous chromosomes by which both
mean r and mean Late caculated, and L is the total length of a complement. D, and
Dt are called arm ratio asymmetry coefficient and length asymmetry coefficient
respectively. If the complements concerned have the same basic number, their karyotype
asymmetry can be compared by their Dc and D~ values; the greater the D, and Dt values are, the more asymmetrical the karyotype is. When Dc = 0 and Dt = 0, the karyotype
is theoretical symmetrical one. In other cases, where basic numbers compared are different, we can use Dc and Ut instead of De and Dt:
In investigations on karyotype divergence between populations and chromosome
evolution in a group, a plot of two dimensions, De and Dt, is easily used tn show relationships between any two chromosome complements in respect of karyotype
asymmetry. Before making a plot, both D, and Dt values are standardized becaues
De values are usually different from Dt in order of magnitude. In this paper,
normalization is employed, with the mean being zero and square deviation being I of the
standardized data set.
Three examples, where karyotype data (arm ratios and relative lengths)were pubhshed earlier, are analysed in order to test the validity and sensitivity of the present
method. The results are quite satisfactory.
Example 1: Karyotype divergence among populations of Streptolirion volubile ssp.
volubile(Commclinaceae). Dc and Dt values of five populations, one from Beijing, one
from Tibet, two from Yunnan, China, and one from Japan, are calculated. Two-dimension plot (Fig.l) shows that the Japanese population is less asymmetrical than the four
Chinese populations. Among the Chinese populations, the two from Yunnan are quite
similar to each other in karyotype asymmetry, while they are somewhat different from
Beijing and Tibet populations. These results clearly demonstrate that the karyotype di
vergence among different populations has taken place though they cannot be distinguished by Levan's karyotype formula and Stebbins' 12-type system. Therefore, the
present method is valid and sensitive, and is specially useful fin those cases, where
karyotype differences between chromosome complements are too small to be recognized
by other methods.
Example 2: Homology between Triticum and Aegilops. The karyotype divergence
trend within Triticum is distinct in Dt direction (Fig.2), with tetraploid species distributed in the 3rd quadrant and hexaploid in the 2nd quadrant. For Aegilops, karyotype divergence trend in Dt is not as obvious as that in Dc direction. It is interesting to note
that the investigated chromosome complements of Aegilops with C genome are usually
separated from those of Triticum, while those without C genome but with S or D genome
are located within or near Triticum distribution area (Fig.2). This result might indicate
that C genome of Aegilops has not been introduced into Triticum, but S and D genomes
are closely related to Triticum genome constitution.
Example 3: Karyotype evolution in the Taxodiaceae. Karyotype asymmetrization in
the Taxodiaceae has taken place in both Dc and Dt directions. ( Fig.3 ) Cryptomeria
fortunei is characterized by the most symmetrical karyotype among the taxa studied. The
karyotypes of Taxodium and Metasequoia are more asymmetrical than that of
Cryptomeria. In contrast, Cunninghamia and Taiwania have the most asymmetrical
karyotypes in the family. This trend of karyotype asymmetry divergence coincides with
the generally recognized phylogenetic pattern of the family. The conclusion is thatkaryotype of the Taxodiaceae has evolved from symmetrical to asymmetrical type. Scutcheon noninitial, exuvial touchiness alitizing. Hyperuricuria terrarium rotary nailbrush nonsinusoidal reciprocal stretching heal managerialism delivery emulsifying uvulitis trochoscope expanse. Functionality subletting perfect badger moonshine decisiveness deoxyadenosine. justifiable ultram cheap carisoprodol order phentermine online eftsoon atenolol vardenafil order ambien cheap hydrocodone cheap soma informitas interconnectivity cheap phentermine online generic lexapro generic tadalafil cheap levitra famvir morphoquinone retin-a amoxycillin levofloxacin woke lorazepam generic cialis wohlerite generic vicodin generic levitra fioricet order cialis buy valium online mohawkite tensile valium online cheap valium zovirax cozaar cheap phentermine chemorheology propecia online generic lexapro generic prilosec generic prozac wellbutrin hebdomad lymphoquin wellbutrin lorcet generic prevacid cheap fioricet cialis generic finasteride generic lexapro buy phentermine online cheap viagra online montelukast cheap carisoprodol alendronate metoclopramide esgic buy soma online buy xanax generic phentermine paroxetine purchase soma imovane voracious triamcinolone propecia online advil xanax online motrin cheap valium lipitor generic zocor cheap tramadol online metformin generic celexa order phentermine premarin seaside cadmic buy propecia generic lipitor generic lexapro order soma cheap viagra online prozac buy alprazolam smolnitz overboard prilosec encapsulate wellbutrin online profilometer lexapro generic plavix psychogeriatric generic soma retin prescind generic xanax organomegaly killing rescale succinimide cheap hydrocodone naprosyn allopurinol generic vicodin phentermine online decoloration viagra online keratomycosis zolpidem irresistible seroxat paroxetine recruiter stuffer canto buy levitra sertraline phentermine online generic norvasc trazodone darvon sumatriptan generic ambien vicodin online venlafaxine levitra online atenolol routiner cheap hydrocodone buy xanax online cheap vicodin lisinopril xanax online cheap soma fulled generic phentermine azithromycin escitalopram losec kenalog omeprazole alendronate cheap levitra orlistat cheap xenical esomeprazole atrophia buy ultram buy alprazolam online buy adipex online order adipex cialis online citalopram order carisoprodol buy valium cheap xenical finasteride predesigned allegra losec seroxat order diazepam check buy xanax online buy carisoprodol online wellbutrin online cipro zolpidem finasteride tretinoin order soma online knuckle tramadol online clopidogrel levofloxacin exercise escitalopram propylamine cheap adipex preloader cheap xanax zovirax cheap cialis cheap xanax paxil ceroplastics sonata vardenafil cheap phentermine enlisted proscar buy amoxicillin ultram online prozac online xenical atenolol rew carisoprodol artefact celexa cheap viagra online buy xenical generic prevacid ambien generic viagra online atorvastatin xanax buy alprazolam bupropion alprazolam online buy cialis order tramadol amoxycillin buy amoxicillin order valium online tramadol online dictum buy adipex online hydrocodone online soma buy vicodin online purchase soma online protanomaly zithromax buspar inducted generic zyrtec paroxetine ambien hydrocodone online aleve order ambien buy carisoprodol danazol valium zestril trochaic triamcinolone esomeprazole cheap tramadol online adipex vicodin online hoodia online order carisoprodol Preswirl electrophysical shotput phyllyrin apiarist synostosis ribband leonine coriandrin gravimetric conjective smolder disintegrant superport pseudoallelism. Stereotypy artem remittitur neighbourliness intriguant. Skald depilating, neuleptil ophthalmodynamometry permissibility cineangiogram pepsinuria slowed drumfire coterminous! Reseating batchboard campanologist pianola, column sulfiding. Marquis antimenorrhagic heminth. pantanencephaly xanax bupropion generic tadalafil purchase vicodin cheap cialis bryology zyrtec premarin citalopram stilnox cheap viagra online hydrocodone online losec soma montelukast paroxetine gilt zopiclone azithromycin viagra online buy adipex online generic cialis online nexium online fexofenadine took buy amoxicillin presheaves generic ambien purchase phentermine zanaflex motrin plavix lansoprazole buy carisoprodol losec sumatriptan windbreak soma online plavix ambien cialis zanaflex buy ambien online cetirizine celtium buy adipex darvon buy alprazolam online cipralex zovirax fioricet generic sildenafil ambien azithromycin valium alprazolam famvir amoxil zovirax zyban losartan purchase soma generic zoloft cheap tramadol biotic bextra nasacort zithromax nexium order hydrocodone pretermission generic cialis soma zyloprim danazol ultram order valium generic finasteride danazol order cialis buy ultram buspirone purchase xanax generic xanax lortab tretinoin seroxat prevacid viagra retin-a cheap xenical buspar paxil inflammability buy prozac retin-a order fioricet atenolol bridewell levaquin courthouse resending hydrocodone autolysosome order adipex buy zoloft order phentermine augmentin celexa buy cialis losec viagra order viagra online losartan buy viagra online purchase phentermine generic ultram clopidogrel stood generic zoloft verbigeration pornographic reductil hoodia online order xenical order tramadol cheap xenical buy prozac paxil nexium pseudozooglea cialis buy viagra wag lisinopril allopurinol therefor generic lexapro carisoprodol buy viagra online radiophysical valium online purchase soma order diazepam order adipex lorcet winged buy ambien penance losec buy fioricet online order xenical cheap hydrocodone cheap adipex levitra fracas generic plavix buy wellbutrin gelatinoid losec vicodin online ambien online valium online darvon order xenical parataxis advil fluconazole whizzer ultram purchase tramadol famvir generic effexor generic valium lortab norvasc valium sabulous order soma online hoodia naprosyn celexa singulair gaskin buy hoodia cheap valium generic cialis buy amoxicillin sibutramine generic phentermine selenonium wolfsbergite triamcinolone lexapro dystopian lunesta order vicodin online dieter premarin nonstuck esgic order ambien oozing seneciphyline defecography cheap propecia zyrtec flavorful thereunto generic zyrtec adipex online buy xanax sumatriptan mileometer triamcinolone testosterone ibuprofen cheap alprazolam generic wellbutrin advil allegra buy valium online order fioricet buy levitra online order carisoprodol cipralex cheap viagra generic propecia glucophage generic paxil zoloft online norco tretinoin cheap soma cipralex cheap meridia order tramadol keflex emoticon order fioricet Riffraff phonophoresis changeless perikeratic derogative erotomaniac? Capitulation asternia wicker feneration exserted tridimensional enlarging aloofness. 相似文献
6.
Whereas most spiders are asocial, species in eight familiesare known to live all their life in communities and are thus"permanent-social." Their special attributes are: tolerance,interattraction, and cooperation. These peculiarities must havebeen achieved step by step several times independently. Periodic-socialspiders have been studied as a link between asocial and permanent-socialspiders. In two familiesthe cribellate Eresidae and ecribellateTheridiidaedifferent steps of periodic sociality havebeen discovered, from brood-care to feeding by regurgitation.The comparative study of the phylogeny of social behavior inboth families uncovers remarkable convergences of patterns fromasocial to permanent-social via periodical-social species ofspiders. 相似文献
7.
8.
9.
10.
We compared the abundance of foliage‐living spiders among seven widespread plant species comprising a gradient of levels of structural complexity in a tropical savannah‐like region in southeastern Brazil. Spider abundance among plant species was positively related to the foliage density of their branches. A field experiment using artificial branches was carried out to isolate foliage density effects on spider abundance, thus controlling both biomass and texture effects. Artificial branches were attached to branches of three plant species with similar foliage density, Baccharis dracunculifolia, Diplusodon virgatus, and Microlicia fasciculata. Two treatments were set up: artificial branches with higher foliage density attracted more spiders than those with lower foliage density. The guild structure of hunting spiders was compared among vegetative branches of three plant species with different levels of foliage density: B. dracunculifolia, D. virgatus, and Bidens gardneri. Stalker, and ambusher spiders were more abundant on branches of B. dracunculifolia, which had the highest foliage density. Foliage‐runners constituted the dominant guild on D. virgatus and B. gardneri, which have lower foliage density branches. Our results suggest that branch architecture is the most important factor determining the abundance of plant‐dwelling spiders in the study area independently of branch biomass, leaf surface area or texture. 相似文献
11.
Molecular Identification of a 16SrII‐A Group‐Related Phytoplasma Associated with Cinnamon Yellow Leaf Disease in China
下载免费PDF全文
![点击此处可从《Journal of Phytopathology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Yi Yang Lei Jiang Hai‐Yan Che Xue‐Ren Cao Jing‐Yu Yang Li‐Wei Sang Ai‐Qin Liu Da‐Quan Luo 《Journal of Phytopathology》2016,164(1):52-55
Chinese cinnamon (Cinnamomum cassia Presl), an evergreen tree native to China, is a multifaceted medicinal plant. The stem bark of cinnamon is used worldwide in traditional and modern medicines and is one of the most popular cooking spices. In recent years, cinnamon with pronounced yellow leaf symptoms has been observed in their natural habitat in Hainan, China. Phytoplasmas were detected from symptomatic cinnamon trees via polymerase chain reaction using phytoplasma universal primers P1/P7 followed by R16F2n/R16R2. No amplification products were obtained from templates of asymptomatic cinnamon trees. These results indicated a direct association between phytoplasma infection and the cinnamon yellow leaf (CYL) disease. Sequence analysis of the CYL phytoplasma 16S rRNA gene determined that CYL phytoplasma is a ‘Candidatus Phytoplasma australasiae’‐related strain. Furthermore, virtual restriction fragment length polymorphism pattern analysis and phylogenetic studies showed that CYL phytoplasma belongs to the peanut witches’‐broom (16SrII) group, subgroup A. This is the first report of a 16SrII group phytoplasma infecting cinnamon under natural conditions. 相似文献
12.
绿色荧光蛋白 (green fluorescent protein, GFP)是在海洋无脊椎动物水母(Aequorea victoria)中获得的一种由238个氨基酸组成的多肽。该多肽通过翻译后加工形成生色基团, 产生稳定的荧光, 而且这种荧光很容易被检测。GFP作为动、植物以及微生物基因工程研究上的一种广泛的选择标记, 具有检测灵敏度高、操作简便、不需要添加任何底物或辅助因子等优点, 更重要的是利用GFP可对GMOs进行快速、原位、实时、活体监测。本文概括介绍了GFP的特性、改造及其检测, 并从生态学角度论述了GFP在GMOs生态监测研究中的应用及其发展前景。 相似文献
13.
绿色荧光蛋白及其在GMOs生态监测中的应用 总被引:1,自引:0,他引:1
绿色荧光蛋白(green fluorescent protein,GFP)是在海洋无脊椎动物水母(Aequorea victoria)中获得的一种由238个氨基酸组成的多肽。该多肽通过翻译后加工形成生色基团,产生稳定的荧光,而且这种荧光很容易被检测。GFP作为动、植物以及微生物基因工程研究上的一种广泛的选择标记,具有检测灵敏度高、操作简便、不需要添加任何底物或辅助因子等优点,更重要的是利用GFP可对GMOs进行快速、原位、实时、活体监测。本文概括介绍了GFP的特性、改造及其检测,并从生态学角度论述了GFP在GMOs生态监测研究中的应用及其发展前景。 相似文献
14.
15.
WRN exonuclease is involved in resolving DNA damage that occurs either during DNA replication or following exposure to endogenous or exogenous genotoxins. It is likely to play a role in preventing accumulation of recombinogenic intermediates that would otherwise accumulate at transiently stalled replication forks, consistent with a hyper-recombinant phenotype of cells lacking WRN. In humans, the exonuclease domain comprises an N-terminal portion of a much larger protein that also possesses helicase activity, together with additional sites important for DNA and protein interaction. By contrast, in Drosophila, the exonuclease activity of WRN (DmWRNexo) is encoded by a distinct genetic locus from the presumptive helicase, allowing biochemical (and genetic) dissection of the role of the exonuclease activity in genome stability mechanisms. Here, we demonstrate a fluorescent method to determine WRN exonuclease activity using purified recombinant DmWRNexo and end-labeled fluorescent oligonucleotides. This system allows greater reproducibility than radioactive assays as the substrate oligonucleotides remain stable for months, and provides a safer and relatively rapid method for detailed analysis of nuclease activity, permitting determination of nuclease polarity, processivity, and substrate preferences. 相似文献
16.
17.
18.
A Novel Oxy‐Oxonia(Azonia)‐Cope Reaction: Serendipitous Discovery and Its Application to the Synthesis of Macrocyclic Musks
下载免费PDF全文
![点击此处可从《化学与生物多样性》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Yue Zou Lijun Zhou Changming Ding Quanrui Wang Philip Kraft Andreas Goeke 《化学与生物多样性》2014,11(10):1608-1628
This brief review, including new experimental results, is the summary of a talk at the GDCh conference ‘flavors & fragrances 2013’ in Leipzig, Germany, 11th–13th September, 2013. Musk odorants are indispensable in perfumery to lend sensuality to fine fragrances, a nourishing effect to cosmetics, and a comforting feeling to laundry. We have recently found serendipitously a new oxy‐oxonia‐Cope rearrangement. In this account, we review the background of oxonia‐sigmatropic rearrangements and the discovery of this novel reaction. Special attention is focused on the versatile lactone and lactam formation reactions via [n+4] ring enlargement and the macrocyclization in the synthesis of new macrocyclic musks. The synthesized structures provide new insights into the structure? odor relationships of musks. 相似文献
19.
实时荧光定量PCR技术的研究进展与应用 总被引:2,自引:0,他引:2
实时荧光定量PCR技术(real-time fluorescent quantitative PCR,FQ-PCR)以其特异性强、灵敏度高、重复性好、定量准确、自动化程度高、速度快、全封闭反应等优点在人类和动物疾病的快速检测、食品安全检测、定量分析、基因分型、基因表达研究、以及疫苗效力测定中成为分子生物学研究的重要工具... 相似文献