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991.
992.
Marianne Cheveau Louis Imbeau Pierre Drapeau Louis Belanger 《The Journal of wildlife management》2013,77(4):749-760
Effects of habitat loss and fragmentation on the behavior of individual organisms may have direct consequences on population viability in altered forest ecosystems. The American marten (Martes americana) is a forest specialist considered as one of the most sensitive species to human-induced disturbances. As some studies have shown that martens cannot tolerate >30–40% clear-cuts within their home range, we investigated marten space use (home range size and overlap) and habitat selection in landscapes fragmented by 2 different patterns of timber harvesting in the black spruce boreal forest: dispersed-cut landscapes (10–80 ha cut-blocks) and clustered-cut landscapes (50–200 ha cut-blocks). We installed radio-collars on female martens and determined 20 winter home ranges (100% minimum convex polygons and 60–90% kernels) in dispersed-cut (n = 8) and clustered-cut (n = 12) landscapes. Home range size was not related to the proportion of clear-cuts (i.e., habitat loss), but rather to the proportion of mixedwood stands 70–120 years old. However, female body condition was correlated to habitat condition inside their home ranges (i.e., amount of residual forest and recent clear-cuts). At the home range scale, we determined that mixedwood forests were also among the most used forest stands and the least used were recent clear-cuts and forested bogs, using resource selection functions. At the landscape scale, home ranges included more mixedwood forests than random polygons and marten high activity zones were composed of more residual forest and less human-induced disturbances (clear-cuts, edges, and roads). These results suggest that mixedwood forests, which occupy approximately 10% of the study area, play a critical role for martens in this conifer-dominated boreal landscape. We recommend permanent retention or special management considerations for these isolated stands, as harvesting mixedwood often leads to forest composition conversion that would reduce the availability of this highly used habitat. © The Wildlife Society, 2013 相似文献
993.
Sérgio L. de Almeida Éder C. Schmidt Debora Tomazi Pereira Marianne Kreusch Marthiellen R. de L. Felix Luz K. P. Osorio Roberta de Paula Martins Alexandra Latini Fernanda Ramlov Fungyi Chow Marcelo Maraschin Ana C. Rodrigues Zenilda L. Bouzon 《Protoplasma》2013,250(6):1303-1313
Ultraviolet-B radiation (UVBR) affects plants in many important ways, including reduction of growth rate and primary productivity, and changes in ultrastructures. Rice (Oryza sativa) is one of the most cultivated cereals in the world, along with corn and wheat, representing over 50 % of agricultural production. In this study, we examined O. sativa plants exposed to ambient outdoor radiation and laboratory-controlled photosynthetically active radiation (PAR) and PAR + UVBR conditions for 2 h/day during 30 days of cultivation. The samples were studied for morphological and ultrastructural characteristics, and physiological parameters. PAR + UVBR caused changes in the ultrastructure of leaf of O. sativa and leaf morphology (leaf index, leaf area and specific leaf area, trichomes, and papillae), plant biomass (dry and fresh weight), photosynthetic pigments, phenolic compounds, and protein content. As a photoprotective acclimation strategy against PAR + UVBR damage, an increase of 66.24 % in phenolic compounds was observed. Furthermore, PAR + UVBR treatment altering the levels of chlorophylls a and b, and total chlorophyll. In addition, total carotenoid contents decreased after PAR + UVBR treatment. The results strongly suggested that PAR + UVBR negatively affects the ultrastructure, morphology, photosynthetic pigments, and growth rates of leaf of O. sativa and, in the long term, it could affect the viability of this economically important plant. 相似文献
994.
Male and female of Goera pitisopai sp. nov. from the Solomon Islands are illustrated and described based on recently collected material. This is the first species of the family Goeridae reported from the Solomon Islands, and the sixth from the Australasian region. 相似文献
995.
Marianne Iversen Jon Aars Tore Haug Inger G. Alsos Christian Lydersen Lutz Bachmann Kit M. Kovacs 《Polar Biology》2013,36(4):561-571
Polar bears (Ursus maritimus) are heavily dependent on marine prey, in particular ice-associated seals, which they hunt on landfast sea ice or free-floating pack ice. Dramatic current (and predicted) losses of sea ice habitat make it increasingly important to gain more knowledge of the relative use by bears of all types of prey from the marine food web as well as from terrestrial sources. This study uses frequency of occurrence of food items in 119 polar bear scats sampled on the sea ice as well as on shore in coastal areas in the Svalbard Archipelago, mainly in spring, between 2003 and 2010 to explore the diet of bears in the region. Ringed seals (Pusa hispida) occurred in 62.2 % (CI 52.8–70.9 %) of the scat samples examined. Various terrestrial plants (32.8 %, CI 24.4–42.0 %) and marine algae (21.8 %, CI 14.8–30.4 %) also occurred frequently in the scats; the significance of this high occurrence of plants and algae is not clear. Bearded seals (Erignathus barbatus) and various bird species constituted only minor components of the diet, while Svalbard reindeer (Rangifer tarandus platyrhynchus) occurred in 9.2 % (CI 4.7–15.9 %) of the scats, indicating that this species may play a more important role than previously reported. The novel combination of genetic analyses of material in the fecal samples along with detailed exploration of the physical–structural properties of prey hairs and plant parts provided a much fuller picture of the diet of polar bears than would have been possible from observational studies of polar bear predation behavior alone. This approach may provide an important tool for monitoring the responses of polar bears to ongoing ecosystem changes that will result from continued warming in the Arctic. 相似文献
996.
997.
Becker J Semler O Gilissen C Li Y Bolz HJ Giunta C Bergmann C Rohrbach M Koerber F Zimmermann K de Vries P Wirth B Schoenau E Wollnik B Veltman JA Hoischen A Netzer C 《American journal of human genetics》2011,(3):11-371
Osteogenesis imperfecta (OI) is a heterogeneous genetic disorder characterized by bone fragility and susceptibility to fractures after minimal trauma. After mutations in all known OI genes had been excluded by Sanger sequencing, we applied next-generation sequencing to analyze the exome of a single individual who has a severe form of the disease and whose parents are second cousins. A total of 26,922 variations from the human reference genome sequence were subjected to several filtering steps. In addition, we extracted the genotypes of all dbSNP130-annotated SNPs from the exome sequencing data and used these 299,494 genotypes as markers for the genome-wide identification of homozygous regions. A single homozygous truncating mutation, affecting SERPINF1 on chromosome 17p13.3, that was embedded into a homozygous stretch of 2.99 Mb remained. The mutation was also homozygous in the affected brother of the index patient. Subsequently, we identified homozygosity for two different truncating SERPINF1 mutations in two unrelated patients with OI and parental consanguinity. All four individuals with SERPINF1 mutations have severe OI. Fractures of long bones and severe vertebral compression fractures with resulting deformities were observed as early as the first year of life in these individuals. Collagen analyses with cultured dermal fibroblasts displayed no evidence for impaired collagen folding, posttranslational modification, or secretion. SERPINF1 encodes pigment epithelium-derived factor (PEDF), a secreted glycoprotein of the serpin superfamily. PEDF is a multifunctional protein and one of the strongest inhibitors of angiogenesis currently known in humans. Our data provide genetic evidence for PEDF involvement in human bone homeostasis. 相似文献
998.
We propose an improved acrylamide gel for the separation of hydrophobic proteins. The separation strategy is based on the incorporation of N-alkylated and N,N′-dialkylated acrylamide monomers in the gel composition in order to increase hydrophobic interactions between the gel matrix and the membrane proteins. Focusing on the most efficient monomer, N,N′-dimethylacrylamide, the potentiality of the new matrix was evaluated on membrane proteins of the human colon HCT-116 cell line. Protein analysis was performed using an adapted analytical strategy based on FT-ICR tandem mass spectrometry. As a result of this comparative study, including advanced reproducibility experiments, more hydrophobic proteins were identified in the new gel (average GRAVY: −0.085) than in the classical gel (average GRAVY: −0.411). Highly hydrophobic peptides were identified reaching a GRAVY value up to 1.450, therefore indicating their probable locations in the membrane. Focusing on predicted transmembrane domains, it can be pointed out that 27 proteins were identified in the hydrophobic gel containing up to 11 transmembrane domains; in the classical gel, only 5 proteins containing 1 transmembrane domain were successfully identified. For example, multiple ionic channels and receptors were characterized in the hydrophobic gel such as the sodium/potassium channel and the glutamate or the transferrin receptors whereas they are traditionally detected using specific enrichment techniques such as immunoprecipitation. In total, membrane proteins identified in the classical gel are well documented in the literature, while most of the membrane proteins only identified on the hydrophobic gel have rarely or never been described using a proteomic-based approach. 相似文献
999.
The misfolding and aggregation of proteins is associated with many different diseases including the trinucleotide repeat disorders and Prion diseases. We have studied three residue peptides comprising alanine and glutamine in order to understand the short range interactions affecting the formation of β-rich aggregates. Using infrared spectroscopy, we have found that trialanine and triglutamine form significant amounts of β-sheet, but that tripeptides containing alanine and glutamine are only able to form β-sheet if the glutamine side-chains extend outward on both faces of the sheet. From our data, we conclude that different stabilizing interactions are responsible for β-sheet formation in trialanine and triglutamine. 相似文献
1000.
Matthew N. Henry Michael A. MacDonald Camila A. Orellana Peter P. Gray Marianne Gillard Kym Baker Lars K. Nielsen Esteban Marcellin Stephen Mahler Verónica S. Martínez 《Biotechnology and bioengineering》2020,117(4):1187-1203
Chinese hamster ovary (CHO) cells are the predominant host cell line for the production of biopharmaceuticals, a growing industry currently worth more than $188 billion USD in global sales. CHO cells undergo programmed cell death (apoptosis) following different stresses encountered in cell culture, such as substrate limitation, accumulation of toxic by-products, and mechanical shear, hindering production. Genetic engineering strategies to reduce apoptosis in CHO cells have been investigated with mixed results. In this review, a contemporary understanding of the real complexity of apoptotic mechanisms and signaling pathways is described; followed by an overview of antiapoptotic cell line engineering strategies tested so far in CHO cells. 相似文献