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61.
Surveys were distributed to New Zealand land users in 1998 and 2008 to acquire information about New Zealand frogs with the aim of compiling and mapping their distribution and inferred population trends without costly and time-consuming field surveys. The overall frog population trend was reported as declining, with possible causes reported as an increase in agriculture, an increase in the distribution of predatory fish and disease. The resultant maps could be used for four main purposes: 1) to identify regions where Litoria populations are known to occur, which can be eliminated when considering suitable regions for translocation of Leiopelma; 2) to identify growing or stable populations of Litoria species, which may assist future disease surveys, population monitoring and to identify sources of genetic material that may serve as an Ark for declining Australian populations; 3) to highlight populations that are in decline to enable effective targeting of detailed disease studies; and 4) to approximate the stability of amphibian populations in the absence of more accurate, but costly, scientific monitoring. 相似文献
62.
Christian Elsner Marcus Lohan Jan Griebel Ulrich Decker 《Biocatalysis and Biotransformation》2013,31(6):444-449
AbstractHydrolysis studies of photo-switchable N-maleyl-amino acid-(4-phenylazophenyl) esters of Ala, Gly, Met, Phe, and Pro were performed using the proteases trypsin and chymotrypsin. It has been found out that the cis-isomers were hydrolyzed faster than the trans-isomers. In dependence of the amino acid in the P1 position the velocity graduation is Phe?>?Met?>?Ala?>?Gly?>?Pro for trypsin and Phe???Met?>?Ala?>?Gly?>?Pro for chymotrypsin for both isomers. 相似文献
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Phosphorylation is the predominant mechanism of post-translational modification for regulation of protein function. With central roles in virtually every cellular process, and strong linkages with many diseases, there is a considerable interest in defining, and ultimately controlling, kinase activities. Investigations of human cellular phosphorylation events, which includes over 500 different kinases and tens of thousands of phosphorylation targets, represent a daunting challenge for proteomic researchers and cell biologists alike. As such, there is a priority to develop tools that enable the evaluation of cellular phosphorylation events in a high-throughput, and biologically relevant, fashion. Towards this objective, two distinct, but functionally related, experimental approaches have emerged; phosphoproteome investigations, which focus on the sub-population of proteins which undergo phosphorylation and kinome analysis, which considers the activities of the kinase enzymes mediating these phosphorylation events. Within kinome analysis, peptide arrays have demonstrated considerable potential as a cost-effective, high-throughput approach for defining phosphorylation-mediated signal transduction activity. In particular, a number of recent advances in the application of peptide arrays for kinome analysis have enabled researchers to tackle increasingly complex biological problems in a wider range of species. In this review, recent advances in kinomic analysis utilizing peptides arrays including several of the biological questions studied by our group, as well as outstanding challenges still facing this technology, are discussed. 相似文献
67.
Rapid vocabulary learning in children has been attributed to "fast mapping", with new words often claimed to be learned through a single presentation. As reported in 2004 in Science a border collie (Rico) not only learned to identify more than 200 words, but fast mapped the new words, remembering meanings after just one presentation. Our research tests the fast mapping interpretation of the Science paper based on Rico's results, while extending the demonstration of large vocabulary recognition to a lap dog. We tested a Yorkshire terrier (Bailey) with the same procedures as Rico, illustrating that Bailey accurately retrieved randomly selected toys from a set of 117 on voice command of the owner. Second we tested her retrieval based on two additional voices, one male, one female, with different accents that had never been involved in her training, again showing she was capable of recognition by voice command. Third, we did both exclusion-based training of new items (toys she had never seen before with names she had never heard before) embedded in a set of known items, with subsequent retention tests designed as in the Rico experiment. After Bailey succeeded on exclusion and retention tests, a crucial evaluation of true mapping tested items previously successfully retrieved in exclusion and retention, but now pitted against each other in a two-choice task. Bailey failed on the true mapping task repeatedly, illustrating that the claim of fast mapping in Rico had not been proven, because no true mapping task had ever been conducted with him. It appears that the task called retention in the Rico study only demonstrated success in retrieval by a process of extended exclusion. 相似文献
68.
Malmuthuge N Li M Chen Y Fries P Griebel PJ Baurhoo B Zhao X Guan LL 《FEMS microbiology ecology》2012,79(2):337-347
The primary aim of this study was to determine whether distinct gastrointestinal tract (GIT) microbial communities are established within ingesta and on mucosal surfaces of dairy calves and chickens to evaluate whether the principle of microbial segregation is of broad biological significance. Multivariate analysis of the predominant bacterial PCR-denaturing gradient gel electrophoresis profiles and estimated bacterial populations were compared in rumen, jejunum, ileum, cecum, and colon ingesta and matching mucosal tissues. Samples collected from 3-week old (n = 8) and 6-month old (n = 8) calves revealed that the predominant mucosa-associated bacteria were distinct from those inhabiting ingesta, and bacterial diversity varied significantly among the GIT regions. The estimated bacterial populations displayed significant regional differences for bovine mucosal (P = 0.05) and for ingesta (P = 0.03) only at 6 months of age. This indicates an established segregation of the enteric bacterial population throughout the GIT in weaned calves. Analysis of ileal and cecal bacterial profiles in chickens confirmed that the segregation of commensal bacteria between ingesta and the mucosal tissue was a common biological phenomenon. Our study provides some fundamental understanding of the impact of sample type (mucosa vs. ingesta), region, and host age on commensal bacterial establishment and segregation throughout the GIT. 相似文献
69.
Emma L Hesketh John RP Knight Rosemary HC Wilson James PJ Chong Dawn Coverley 《Cell cycle (Georgetown, Tex.)》2015,14(3):333-341
The minichromosome maintenance complex (MCM2-7) is the putative DNA helicase in
eukaryotes, and essential for DNA replication. By applying serial extractions to mammalian
cells synchronized by release from quiescence, we reveal dynamic changes to the
sub-nuclear compartmentalization of MCM2 as cells pass through late G1 and early S phase,
identifying a brief window when MCM2 becomes transiently attached to the nuclear-matrix.
The data distinguish 3 states that correspond to loose association with chromatin prior to
DNA replication, transient highly stable binding to the nuclear-matrix coincident with
initiation, and a post-initiation phase when MCM2 remains tightly associated with
chromatin but not the nuclear-matrix. The data suggests that functional MCM complex
loading takes place at the nuclear-matrix. 相似文献
70.
The lateralization of sensory and motor functions has been recently demonstrated in various groups of vertebrates. We examined lateral asymmetry of eye use in Octopus vulgaris by behavioural methods. Octopus vulgaris uses monocular vision almost exclusively and can move its eyes independently. The amount of binocular vision is small because the eyes are on the sides of the head. We tested eight octopuses in two conditions (one with and one without moving stimuli) where the use of the eye for frontal vision could be determined unequivocally. Data were recorded on videotape. All animals showed a preference for one eye (five left, three right). There was no correlation between eye use and the animal's direction of movement. Pigmentation of the ventral side of the arms tended to be most intense on the side of the preferred eye and the body was most pigmented on the side of the eye currently in use. We found no sex differences for visual lateralization. Pigmentation of the ventral side of the arms was lighter in females than in males. Copyright 2002 The Association for the Study of Animal Behaviour. Published by Elsevier Science Ltd. All rights reserved. 相似文献