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11.
12.
Jorge E. Ramos Gretta T. Pecl Natalie A. Moltschaniwskyj Jan M. Strugnell Rafael I. León Jayson M. Semmens 《PloS one》2014,9(8)
Understanding the response of any species to climate change can be challenging. However, in short-lived species the faster turnover of generations may facilitate the examination of responses associated with longer-term environmental change. Octopus tetricus, a commercially important species, has undergone a recent polewards range shift in the coastal waters of south-eastern Australia, thought to be associated with the southerly extension of the warm East Australian Current. At the cooler temperatures of a polewards distribution limit, growth of a species could be slower, potentially leading to a bigger body size and resulting in a slower population turnover, affecting population viability at the extreme of the distribution. Growth rates, body size, and life span of O. tetricus were examined at the leading edge of a polewards range shift in Tasmanian waters (40°S and 147°E) throughout 2011. Octopus tetricus had a relatively small body size and short lifespan of approximately 11 months that, despite cooler temperatures, would allow a high rate of population turnover and may facilitate the population increase necessary for successful establishment in the new extended area of the range. Temperature, food availability and gender appear to influence growth rate. Individuals that hatched during cooler and more productive conditions, but grew during warming conditions, exhibited faster growth rates and reached smaller body sizes than individuals that hatched into warmer waters but grew during cooling conditions. This study suggests that fast growth, small body size and associated rapid population turnover may facilitate the range shift of O. tetricus into Tasmanian waters. 相似文献
13.
Yasutaka Kakui Tomonari Sunaga Kunio Arai James Dodgson Liang Ji Attila Csikász-Nagy Rafael Carazo-Salas Masamitsu Sato 《Open biology》2015,5(6)
Integration of an external gene into a fission yeast chromosome is useful to investigate the effect of the gene product. An easy way to knock-in a gene construct is use of an integration plasmid, which can be targeted and inserted to a chromosome through homologous recombination. Despite the advantage of integration, construction of integration plasmids is energy- and time-consuming, because there is no systematic library of integration plasmids with various promoters, fluorescent protein tags, terminators and selection markers; therefore, researchers are often forced to make appropriate ones through multiple rounds of cloning procedures. Here, we establish materials and methods to easily construct integration plasmids. We introduce a convenient cloning system based on Golden Gate DNA shuffling, which enables the connection of multiple DNA fragments at once: any kind of promoters and terminators, the gene of interest, in combination with any fluorescent protein tag genes and any selection markers. Each of those DNA fragments, called a ‘module’, can be tandemly ligated in the order we desire in a single reaction, which yields a circular plasmid in a one-step manner. The resulting plasmids can be integrated through standard methods for transformation. Thus, these materials and methods help easy construction of knock-in strains, and this will further increase the value of fission yeast as a model organism. 相似文献
14.
M N Melo P Williams N M Rocha E H Babá W Mayrink M S Michalick C A da Costa M Dias P A Magalh?es 《Memórias do Instituto Oswaldo Cruz》1987,82(4):557-561
Attempts have been made to characterize two strains of Leishmania that became infective to golden hamsters only after they had been maintained for several years in a chemically defined culture medium. Observations were made on the growth rates of promastigotes in vitro, course of infection in hamsters, morphology of amastigotes, and electrophoretic mobility patterns of eight isoenzymes. Information was obtained about the buoyant densities of n-DNA and k-DNA, and one strain was tested against monoclonal antibodies. The identity of both strains remains obscure. 相似文献
15.
Rafael Cantera 《Cell and tissue research》1988,253(2):425-433
Summary The presence and distribution of neurons immunoreactive against antibodies to serotonin (5-HT) and gastrin/cholecystokinin (gastrin/CCK) has been studied in the larval retrocerebral complex of the blowfly Calliphora erythrocephala, a composite structure which consists of the corpus cardiacum, the corpus allatum, the thoracic gland and a portion of the cephalic aorta. Immunoreactive material was found in all these elements except in the corpus allatum. Six to eight cell bodies in the corpus cardiacum and four to eight cell bodies in the thoracic gland were 5-HT immunoreactive (5-HTi). These 5-HTi cell bodies send processes to the neuropil of the corpus cardiacum and to neurohemal sites in the cephalic aorta, corpus cardiacum and ventral part of the thoracic gland. Six to eight cell bodies in the corpus cardiacum and four to six cell bodies in the thoracic gland reacted with antibodies against gastrin/CCK. These cell bodies send processes to the neuropil of the corpus cardiacum and to neurohemal sites in the corpus cardiacum and the cephalic aorta in a pattern resembling that of the 5-HTi fibers. Additional gastrin/CCK-like immunoreactive fibers were shown to come from the central nervous system via the two nervi corporis cardiaci. An electron-microscopical analysis was performed to analyze further the morphological features revealed by the light-microscopic immunocytochemical technique. This confirmed the existence of neurosecretory-like terminals among the gland cells of the thoracic glands and the existence of neurohemal sites in several regions of the larval retrocerebral complex. Some functional aspects of the retrocerebral complex are discussed on the basis of the presented data. 相似文献
16.
To assess the dynamics of synthesis of the wall by regenerating Candida albicans protoplasts deposition of chitin and mannoproteins were investigated ultrastructurally using wheat germ agglutinin conjugated with either horseradish peroxidase or colloidal gold, and Concanavalin A coupled to ferritin respectively.Freshly prepared protoplasts lacked wheat germ agglutinin receptor sites but after 1–2 h of regeneration, they were detected. After 4–5 h of regeneration, the cell wall showed a discrete structure which was only labelled with wheat germ agglutinin in thin sections. At this stage of regeneration the outermost layer of the wall was labelled with clusters of Concanavalin A-ferritin particles.After 8 h regeneration, the cell wall appeared compact, and homogenously marked with wheat germ agglutinin whereas only the surface layers appeared consistently labelled with Concanavalin A-ferritin.From these observations we conclude that C. albicans protoplasts are able to regenerate in liquid medium a cell wall consisting of a network of chitin fibrils and mannoproteins at least (glucan polymers were not determined in the present cytological study). The former are the fundamental component of the inner layers at early stages of regeneration, whereas the latter molecules are predominant in the outer layers of the wall.Abbreviations WGA-HRP
wheat germ agglutinin conjugated with horseradish peroxidase
- WGA-Au
wheat germ agglutinin conjugated with colloidal gold
- Con A-ferritin
Concanavalin A coupled to ferritin 相似文献
17.
F. Javier Caballero M. Isabel Igeño Rafael Quiles Francisco Castillo 《Archives of microbiology》1992,158(1):14-18
Rhodobacter capsulatus strains E1F1 and B10 and Rhodobacter sphaeroides DSM 158 did not use hydroxylamine as nitrogen source for growth but metabolized it mainly through the glutamine synthetase reaction. Hydroxylamine had a high toxicity for cells growing either under phototrophic or dark-aerobic conditions. l-methionine-d,l-sulfoximine partially inhibited hydroxylamine uptake and increased the inhibition time of nitrogenase activity by this nitrogen compound. Nitric oxide was also a powerful inhibitor of nitrogenase in intact cells of R. capsulatus. Since low amounts of NO were produced from hydroxylamine, short-term inhibition of nitrogenase in the presence of this compound could be mediated in vivo by nitric oxide.Abbreviations GS
glutamine synthetase
- MSX
l-methionine-d,l-sulfoximine
- MTA
mixed alkyltrimethylammonium bromide 相似文献
18.
Vicent Casadó Carmen Lluis Enrique Canela Rafael Franco Josefa Mallol 《Neurochemical research》1992,17(2):129-139
Pig brain cerebral cortex was subfractionated by isopycnic centrifugation in sucrose gradients. In each subfraction the content of the agonist [3H]R-PIA binding, the activity of adenosine metabolizing enzymes (5-nucleotidase and adenosine deaminase) and the activity of membrane marker enzymes were determined. The fractions were also examined by electron microscope. In general, the results suggest a widespread distribution of A1 adenosine receptors in membranes from different origins. Marker enzyme profile characterization indicated an enrichment of A1 adenosine receptor in pre-synaptic membranes isolated from the crude synaptosomal fraction (P2B subfraction) as well as in membranes of glial origin such as myelin. The receptor is also present in the endoplasmic reticulum and in membranes isolated from the microsomal fraction that seem to have a post-synaptic origin (P3B). In subfractions having a high content of adenosine receptor the equilibrium binding paramters were obtained as well as the proportion of high- to low-affinity sites. From the values of the equilibrium constants it was not possible to find differences between the receptor in the different subfractions. Analysis of the affinity state distribution showed a diminished percentage of high-affinity sites in fraction P3A, which can be accounted by the existence of myelin membranes; in contrast the percentage of high-affinity states was higher in P2 and P3B, indicating that in these fractions the receptor is present in synaptosomal membranes. The close correlation shown between the enzyme 5-nucleotidase specific activity and the specific ligand binding distributions led us to postulate an important role for the enzyme in the regulation of adenosine action in pig brain cortex. 相似文献
19.
Rafael Navarro-González Cyril Ponnamperuma Raj K. Khanna 《Origins of life and evolution of the biosphere》1991,21(5-6):359-374
Cometary nuclei have been exposed to high levels of ionizing radiation since their formation. We present here some results of a computer model calculation of the effect of ionizing radiation on cometary material. The external (cosmic rays) and internal (embedded radionuclides) contributions in the processing of cometary nuclei are considered. As a first approximation we have used the available kinetic data of the liquid water system to model the radiation effects in a frozen cometary environment. Out data suggest that massive radiation chemical processing due to cosmic rays may have taken place only in the outer layers of comets. The internal contribution of radionuclides to the radiation processing of comet cores seems to be modest. Therefore, comets could be carriers of intact homochiral biomolecules.Part of this work was carried out during a leave at the Laboratory of Chemical Evolution. 相似文献
20.
Rafael Navarro-González Susana Castillo-Rojas Alicia Negrón-Mendoza 《Origins of life and evolution of the biosphere》1991,21(1):39-49
The radiation-induced decomposition of aqueous solutions of formaldehyde was studied at 298 and 77 K in order to obtain an insight into the possible role of ionizing radiation on cometary chemistry. Aqueous solutions of 1.0 mol dm–3 formaldehyde were exposed to -radiation in the dose range from 0.01 kGy to 1.2 MGy. The radiation chemical yield of decomposition of formaldehyde was determined to be: G(–CH2(OH)2)=26.3±1.2 at 298 K and G0.48 at 77 K.Based on previous estimates of the total dose of ionizing radiation that comets have accumulated over 4.6 billion years, we predict a radiation-induced depletion of formaldehyde as a function of depth in comet nuclei: 100% destruction in the outer layers (0–20 m) and 10% destruction in the interior layers.A Portion of this work was presented at the XXVIII COSPAR Plenary Meeting (MF. 7) held at the Hague, The Netherlands on June 25–26, 1990. 相似文献