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81.
Three Athalia sawflies, A. japonica, A. rosae and A. infumata, feeding on cruciferous plants, coexist in Japan. However, it is not known what ecological strategies they use and what environmental factors are crucial to such strategies. I attempted to explain these questions by examining the relationship between the spatio-temporal distribution patterns of three Athalia sawflies and their habitats in three districts (Lowland, Intermediate and Mountain). The three sawflies have different spatio-temporal distribution patterns, though they usually used common cruciferous plants. A. japonica was abundant in spring and autumn but disappeared during summer in all the districts. In the Lowland, populations of A. rosae and A. infumata, like that of A. japonica, crashed in summer. However A. rosae occurred mainly in summer in the Intermediate and Mountain. Although A. infumata occurred in the same seasons as A. rosae in all districts, population levels of A. infumata were always lower than those of A. rosae. The crucial factors controlling their population patterns were the availability of host plants and temperature. Population crashes of A. rosae and A. infumata were due to food depletion, and those of A. japonica were due to heat stress. On the other hand, their population patterns may be interpreted as phenological synchronization with their original host plants, though they all existed on common cruciferous plants. The three sawflies may have evolved different strategies to escape from unfavorable habitat conditions. Such strategies are speculated to be summer diapause in A. japonica, long distance migration in A. rosae, and local dispersal in A. infumata.  相似文献   
82.
Summary We studied the relationship between habitat moisture and gall-forming insect populations. Population sizes for most galling taxa were significantly larger in xeric habitats compared with mesic habitats. Our results indicate that the differential abundance of galling insects in these habitats is due primarily to differential mortality and survivorship. Mortality factors acting upon eight insect galling species (belonging to eight genera and four families) were measured on six species (five genera and five families) of host plants. Survival was significantly higher for galling populations inhabiting xeric habitats compared with mesic habitats. Parasitism was higher in mesic habitats in seven of eight habitats and fungus-induced diseases were higher in five of seven habitats. Mortality due to predation and other (unknown) factors showed no clear trends. Overall, there was a tendency towards lower mortality and consequently higher survival for populations inhabiting xeric habitats. We hypothesize that reduced mortality caused by natural enemies and endophytic fungi has contributed to the speciation and radiation of galling insects in apparently harsh environments.  相似文献   
83.
Morphological, cytological and ecological observations were made onLycopodium clavatum. Among 121 individuals from 26 populations studied 31 were of the diploid cytotype with 2n=68, 45 were of the triploid cytotype with 2n=102 and 45 were of the tetraploid cytotype with 2n=136. The populations were divided into three types: (1) the sole type—characterized by a single cytotype occupying an entire population, (2) the mixed type A—characterized by two or three cytotypes occupying together the same population, but each cytotype choosing different habitats, (3) the mixed type B—characterized by two or three cytotypes occupying together the same population and sharing the same habitat with each other. The mixed type B populations were found in the places of the early phase of secondary succession in a plant community. In the sole type and the mixed type A, the habitat preference for each cytotype was described as follows: the habitat for the diploid was in humid and shady places, that for the tetraploid was in open and sunny, unstable places, and that for the triploid was intermediate between the other two. Each cytotype can progress towards occupying their optimum habitat successively from the mixed type B population to the mixed type A population and finally reaching the sole type population.  相似文献   
84.
Polyacrylamide gradient gel electrophoresis was carried out in micellar solutions of various detergents which differ in degree of potency to denature proteins. From the application of this method to band 3 protein from erythrocyte membranes, it was suggested that the procedure was useful in studying the molecular state of membrane proteins.The electrophoretic behaviors of human and bovine band 3 protein did not show any species specificity in either a denature state and a state resembling the native state. As well as in nonionic detergent solutions, the dimeric and tetrameric structures of bovine band 3 protein were preserved in sodium deoxycholate solution, in which protein complexes maintained in nonionic detergent solutions are frequently dissociated. Even in dodecyltrimethylammonium bromide solution, which is a denaturant for water-soluble proteins, part of the band 3 protein was still present as the oligomer. The results suggest that the oligomeric form of band 3 protein is the stable structure and that the dimer and tetramer possibly coexist in membranes.  相似文献   
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A new species of anaerobic bacterium that degrades the even-numbered carbon fatty acids, butyrate, caproate and caprylate, to acetate and H2 and the odd-numbered carbon fatty acids, valerate and heptanoate, to acetate, propionate and H2 was obtained in coculture with either an H2-utilizing methanogen or H2-utilizing desulfovibrio. The organism could be grown only in syntrophic association with the H2-utilizer and no other energy sources or combination of electron donor and acceptors were utilized. It was a Gram-negative helical rod with 2 to 8 flagella, about 20 nm in diameter, inserted in a linear fashion about 130 nm or more apart along the concave side of the cell. It grew with a generation time of 84 h in co-culture with Methanospirillum hungatii and was present in numbers of at least 4.5×10-6 per g of anaerobic digestor sludge.  相似文献   
88.
In literature, an effective method enabling the classification, based on a single indicator, of habitats that need a priority protection intervention has not been identified yet. Moreover, the excessive number of landscape metrics, used to quantify integrity of habitats, can cause confusion, often providing redundant and inconsistent results.The aim of this work is to develop a method for evaluating the ecological vulnerability of the habitats in sites of high biodiversity conservation interest. In the first phase, we selected and analyzed, by using principal component analysis (PCA) and fuzzy logic, the landscape metrics, in order to obtain the map of the intrinsic ecological vulnerability index. In the second step, the result of this intrinsic vulnerability was connected, through another fuzzy model, to anthropogenic impacts, obtaining the integrated ecological vulnerability index. We developed specific spatial indicators (landscape metrics), which can examine the mutual position and morphology of the habitats present, along with indicators of human pressure, related to the type and intensity of use of the anthropic territory, with reference to the habitat itself as well as to the areas immediately adjacent. The developed fuzzy models are innovative, compared to the current ecological studies, and examine landscape metrics as well as the impact of human activities.The case study is the “Val Basento-Ferrandina Scalo” Site of Community Importance, Ferrandina-SCI (Basilicata Region, Southern Italy). The results allowed us to build a rank of the habitats based on their intrinsic and integrated ecological vulnerability. Moreover, the results show that, in the Ferrandina-SCI, the most important source of concern is not human activities, but rather the inherent risk of ecological fragility caused by geographical and landscape features of the different patches of habitats themselves.This model aims to be a tool for decision support in sustainable landscape management. It is easy to use and to apply on other regions, although it should always be accompanied by a sensitivity analysis to reduce the subjectivity.  相似文献   
89.
Human use of the ocean and its ecosystems continues to degrade coastal habitats around the world. Assessing anthropogenic impacts on these environments can be costly and manpower-intensive; thus, the development of rapid, remote techniques to assess habitat quality is important. We employed autonomous hydrophone receivers to record the soundscapes of healthy, sponge-rich hard-bottom habitat in Florida Bay, Florida (USA) and hard-bottom areas impacted by sponge die-offs. We also recorded sounds emanating from individual sponges of three species that were isolated in underwater sound booths, and then enumerated the invertebrates (mostly snapping shrimp) dwelling within the canals of each sponge. From these recordings, a modified cylindrical sound propagation model was used to estimate distances to individual snapping shrimp snaps. Using the program Distance, we estimated snapping shrimp population density and abundance within both habitat types. More snapping shrimp snaps per unit time were recorded in healthy hard-bottom areas as compared to degraded hard-bottom areas. In addition, the average distance to a snap source was greater within degraded hard-bottom areas than within healthy hard-bottom areas. As a consequence, the estimated density and abundance of snapping shrimp were one to two orders of magnitude greater within healthy habitat than within degraded habitat. This study demonstrates the feasibility of using acoustic sampling and modeling to rapidly assess populations of soniferous benthic indicator species, whose vocalizations may yield indirect estimates of habitat quality.  相似文献   
90.
Microbes play important roles in human health and disease. The interaction between microbes and hosts is a reciprocal relationship, which remains largely under-explored. Current computational resources lack manually and consistently curated data to connect metagenomic data to pathogenic microbes, microbial core genes, and disease phenotypes. We developed the MicroPhenoDB database by manually curating and consistently integrating microbe-disease association data. MicroPhenoDB provides 5677 non-redundant associations between 1781 microbes and 542 human disease phenotypes across more than 22 human body sites. MicroPhenoDB also provides 696,934 relationships between 27,277 unique clade-specific core genes and 685 microbes. Disease phenotypes are classified and described using the Experimental Factor Ontology (EFO). A refined score model was developed to prioritize the associations based on evidential metrics. The sequence search option in MicroPhenoDB enables rapid identification of existing pathogenic microbes in samples without running the usual metagenomic data processing and assembly. MicroPhenoDB offers data browsing, searching, and visualization through user-friendly web interfaces and web service application programming interfaces. MicroPhenoDB is the first database platform to detail the relationships between pathogenic microbes, core genes, and disease phenotypes. It will accelerate metagenomic data analysis and assist studies in decoding microbes related to human diseases. MicroPhenoDB is available through http://www.liwzlab.cn/microphenodb and http://lilab2.sysu.edu.cn/microphenodb.  相似文献   
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