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Abstract. The authors have previously shown that cell treatments causing intra-cellular alkalinization stimulate the in vivo phosphorylation of a 33-K Dalton polypeptide (33 KP) (Tognoli & Basso, 1987). Here, the authors report that this polypeptide belongs to a protein associated with the microsomal membranes. They show that treatment of cells which induce intracellular alkalinization stimulate 33-KP phosphorylation, whether the phosphorylation is performed in vivo (cells loaded with 32 Pi before treatments) or in vitro (microsomes from control and treated cells, incubated with γ32 P ATP). In both cases, 33 KP is phosphorylated on a serine residue. Microsomes do not show any phosphatase activity towards this phosphorylated protein, indicating involvement of a protein kinase reaction as an effector of changes induced by intracellular alkalinization. The number of phosphorylated sites or molecules of this protein increases as a result of intracellular alkalinization, suggesting that intracellular alkalinization causes topological or conformational modifications to a protein kinase or its substrate protein. The in vitro phosphorylation is not specifically influenced by the pH of the in vitro phosphorylation medium, suggesting that protein phosphorylation is not directly controlled by cytoplasmic pH. 相似文献
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L GIUNCHEDI C POGGI POLLINI S BIONDI ANNA ROSA BABINI 《The Annals of applied biology》1994,124(2):399-403
Polymerase chain reaction (PCR) amplification, using primers derived from the 16S rRNA gene, followed by restriction fragment length polymorphism (RFLP) analysis with Alu I restriction endonuclease was used to detect myc-oplasma-like organisms (MLOs) associated with pear decline. MLOs were consistently detected in pear trees that suddenly wilted and died within a few days during summer, as well as in pears of the same orchards with symptoms similar to the slow form of pear decline. In both cases the same RFLP pattern was obtained. Declining pear trees were 5 to 8-yr-old cvs Williams, Kaiser and Max Red Bartlett grafted on to Pyrus communis seedling rootstocks. All the orchards affected by quick decline had severe attacks of pear psyllid (Cacopsylla pyri) during the year this study was performed and during the previous year. The results showed the suitability of DNA amplification by the polymerase chain reaction for the detection of pear decline MLOs and established that MLOs can be detected in infected tissues of dead trees. 相似文献
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In maize coleoptiles (Zea mays F1 XL 640A, cv. Dekalb) canavanine and cycloheximide strongly and simultaneously inhibit cell elongation, H+ extrusion and K+ uptake, induced by IAA. They inhibit also, although to a much lesser degree, the same phenomena induced by fusicoccin. Cycloheximide severely depresses the incorporation of leucine into proteins, while canavanine leaves leucine incorporation almost unchanged. The data confirm that elongation, H+ extrusion and K+ uptake can be regarded as correlated processes; they also support the view that normal protein synthesis is essential for IAA-induced growth, while this requirement is only partial in growth stimulated by fusicoccin. 相似文献
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JORDI DE GIBERT ROSA DOMÈNECH JORDI MARTINELL 《Lethaia: An International Journal of Palaeontology and Stratigraphy》2004,37(4):429-437
Animal bioerosion trace fossils upon mineral substrates are analyzed from the point of view of the Seilacherian ethological classification. Several of the currently accepted ethological classes: cubichnia, fugichnia, repichnia, fodinichnia, agrichnia, calichnia and aedificichnia are not represented in these substrates. This fact points out a lower behavioral diversity of hard substrate trace fossils when compared with soft sediment trace fossils. Bioerosion traces can be classified in just five classes: domichnia, pascichnia, equilibrichnia, praedichnia and fixichnia. Fixichnia is here erected to gather superficial etching scars resulting from the anchoring of fixation of sessile epiliths by means of a soft or skeletal body part. Praedichnia and fixichnia are exclusive of the bioerosion realm. 相似文献
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ABSTRACT This paper presents a framework effort to allow the experimentation of various devices in order to automatically record, detect and classify marine mammal vocalizations in the open sea. Some tools for the protection of Killer Whales and other cetaceans are founded in the analysis of their recorded vocalizations. With this framework we are able to test every part under controlled conditions before open sea experiments. Some of these devices have been designed to localize and track open sea populations in order to facilitate data collection for conservation management. At this moment the framework consists of the basic necessary instruments and IT resources for continuously multichannel recording of vocalizations from four specimens of Killer Whale. The enormous raw data stream forces the implementation of a data reduction strategy. As a result, the present research is focused in the development of techniques for this purpose that will allow the automatic classification of events and obtain statistical data. Complementarily, our research goals are also focused on the design of prototypes for source localization using time tags of events on multiple channels for continuous real time logging of behaviour and position of specimens. This paper presents some preliminary results of automatically detected calls. 相似文献
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ROCÍO ROSA GARCÍA BERTA M. JÁUREGUI URCESINO GARCÍA KOLDO OSORO RAFAEL CELAYA 《Ecological Entomology》2009,34(4):466-475
Abstract 1. The effects of different goat breeds and grazing pressures on epigeal arachnids (Lycosidae and Opiliones) and ground beetles (Carabidae) were assessed in a heath–gorse shrubland located in the north of the Iberian Peninsula. Three treatments (low grazing pressure with Cashmere breed, high grazing pressure with Cashmere breed, and high grazing pressure with local Celtiberic breed) with three replicates of each treatment were allocated randomly to nine plots. 2. Arthropod fauna abundance, diversity, and species richness were estimated using pitfall trapping over 3 years (2003, 2004, and 2005). Vegetation cover, composition, and height were assessed along transects and above‐ground plant biomass was sampled in quadrats. 3. Lower grazing pressure led to lower herbaceous cover and higher heather cover than high grazing pressure. Overall, it did not enhance arthropod diversity or abundance, but the abundance and species richness of carabids, and abundance of lycosids like Pardosa pullata, were higher under high stocking rates, whereas Opiliones were favoured by the low stocking rates. Although it has been assumed that traditional breeds enhance biodiversity, the present study found no significant differences for both arthropod fauna and vegetation between the goat breeds. 4. Arthropod–vegetation relationships were examined by constrained ordination. Fauna assemblages followed a gradient from closed canopy shrubland areas, in the lowest grazing pressure, to grassier open canopy areas resulting from higher grazing pressure, revealing the importance of grazing management as a driver of arthropod community structure of the heathland. 相似文献
8.
JAIME POLOP GLADYS CALDER
N MARÍA ROSA FEUILLADE JORGE GARCÍA DELIA ENRIA MARTA SABATTINI 《Austral ecology》2007,32(3):245-253
Abstract Argentine haemorrhagic fever (AHF) is caused by Junin (JUN) virus, which is hosted by the drylands vesper mouse (Calomys musculinus). In this work we monitored population abundance of C. musculinus and rodent assemblages for 3 years in and outside the AHF endemic zones (northern Buenos Aires, southern Córdoba and Santa Fe Provinces, Argentina). The study area was divided into endemic and nonendemic zones. In the endemic zone epidemic sites were recognized, characterized by recent emergence and maintenance of AHF cases, and also historical sites, characterized by decreased incidence or disappearance of AHF human cases. In the nonendemic zone AHF has never been recognized. Although differences were statistically significant only during some periods, population abundance of C. musculinus was usually lower in the nonendemic sites. The pattern and magnitude of seasonal fluctuations in C. musculinus populations were also distinct in the nonendemic sites as compared to endemic sites. The relative abundance of C. musculinus in rodent assemblage was lower in nonendemic sites than in the endemic sites. The lower population densities and dampened seasonal dynamics may be at least partly responsible for the absence of AHF cases in the nonendemic zone. It is suggested that the balance between intra and interspecific interactions might be the cause of the pattern of incidence and prevalence of pathogens in the host species. 相似文献
9.
BRIAN P. DREHER SCOTT R. WINTERSTEIN KIM T. SCRIBNER PAUL M. LUKACS DWAYNE R. ETTER GUILHERME J. M. ROSA VERONICA A. LOPEZ SCOT LIBANTS KRISTI B. FILCEK 《The Journal of wildlife management》2007,71(8):2684-2693
ABSTRACT Estimating black bear (Ursus americanus) population size is a difficult but important requirement when justifying harvest quotas and managing populations. Advancements in genetic techniques provide a means to identify individual bears using DNA contained in tissue and hair samples, thereby permitting estimates of population abundance based on established mark-capture-recapture methodology. We expand on previous noninvasive population-estimation work by geographically extending sampling areas (36,848 km2) to include the entire Northern Lower Peninsula (NLP) of Michigan, USA. We selected sampling locations randomly within biologically relevant bear habitat and used barbed wire hair snares to collect hair samples. Unlike previous noninvasive studies, we used tissue samples from harvested bears as an additional sampling occasion to increase recapture probabilities. We developed subsampling protocols to account for both spatial and temporal variance in sample distribution and variation in sample quality using recently published quality control protocols using 5 microsatellite loci. We quantified genotyping errors using samples from harvested bears and estimated abundance using statistical models that accounted for genotyping error. We estimated the population of yearling and adult black bears in the NLP to be 1,882 bears (95% CI = 1,389-2,551 bears). The derived population estimate with a 15% coefficient of variation was used by wildlife managers to examine the sustainability of harvest over a large geographic area. 相似文献
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