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51.
Paulino Bambi Alan M. Tonin Renan de Souza Rezende Fernando Carvalho Vieira Fernanda Gabriela Graciano Miranda Luz Boyero José F. Gonçalves Júnior 《Biotropica》2023,55(1):40-52
Riparian forests play an important role in stream ecosystems, as they support biodiversity, reduce water erosion, and provide litter that fuels aquatic biota. However, they are affected by great array of anthropogenic threats (e.g., fire, logging, and organic pollution), which alter species composition and their physical structure. Although forest recovery after disturbance such as logging can take decades, the legacy of forest clear-cut logging on key processes in tropical riparian ecosystems is mostly unknown. Here, we investigated how litter inputs (leaves, twigs, and reproductive parts) and storage, key processes for carbon and nutrient recycling and for forest and stream biota, are influenced by riparian vegetation undergoing succession (after 28 years from logging) through the comparison of reference and logged forest sites in the Cerrado biome. Litterfall was overall similar between forest types, but litterfall of twigs was twofold higher at logged than reference sites. Similarly, litter inputs from the bank to the stream (i.e., lateral inputs) and streambed storage were 50–60% higher at logged than reference sites. The higher litterfall observed in logged forests could be related to higher proportion of tree species that are characteristic of primary and secondary successional stages, including fast-growing and liana species, which often are more productive and common in anthropogenic areas. Our results showed that the legacy impact of clear-cut logging, even if residual woody vegetation is maintained in riparian buffers, can shift the type, quantity, and seasonality of litter subsidies to tropical streams. This knowledge should be considered within the context of management and conservation of communities and ecosystem processes in the forest-stream interfaces. 相似文献
52.
Barindra Sana Ke Ding Jia Wei Siau Rupali Reddy Pasula Sharon Chee Sharad Kharel Jean-Baptise Henri Lena Eunice Goh Lakshminarayanan Rajamani Yeng Ming Lam Sierin Lim John F. Ghadessy 《Biotechnology and bioengineering》2023,120(11):3200-3209
Polyethylene terephthalate (PET) hydrolase enzymes show promise for enzymatic PET degradation and green recycling of single-use PET vessels representing a major source of global pollution. Their full potential can be unlocked with enzyme engineering to render activities on recalcitrant PET substrates commensurate with cost-effective recycling at scale. Thermostability is a highly desirable property in industrial enzymes, often imparting increased robustness and significantly reducing quantities required. To date, most engineered PET hydrolases show improved thermostability over their parental enzymes. Here, we report engineered thermostable variants of Ideonella sakaiensis PET hydrolase enzyme (IsPETase) developed using two scaffolding strategies. The first employed SpyCatcher-SpyTag technology to covalently cyclize IsPETase, resulting in increased thermostability that was concomitant with reduced turnover of PET substrates compared to native IsPETase. The second approach using a GFP-nanobody fusion protein (vGFP) as a scaffold yielded a construct with a melting temperature of 80°C. This was further increased to 85°C when a thermostable PETase variant (FAST PETase) was scaffolded into vGFP, the highest reported so far for an engineered PET hydrolase derived from IsPETase. Thermostability enhancement using the vGFP scaffold did not compromise activity on PET compared to IsPETase. These contrasting results highlight potential topological and dynamic constraints imposed by scaffold choice as determinants of enzyme activity. 相似文献
53.
Kinley Ragan Jan Schipper Heather L. Bateman Sharon J. Hall 《The Journal of wildlife management》2023,87(1):e22322
Wildlife populations in semi-arid regions are increasingly challenged by human activities and dependent on the connectivity of riparian corridors for access to surface water. The Madrean Archipelago is a biodiversity hotspot along the arid United States–Mexico borderlands that support both Neotropical and Nearctic wildlife. Infrastructure development (e.g., the border wall and the expansion of Mexican Federal Highway 2) in this region inhibits wildlife movement along the transnational mountain archipelago by disconnecting habitat. To explore the relationship between habitat variables and mammal use of riparian corridors in northern Sonora, Mexico, we collected data from 19 motion-sensitive cameras between October 2018 and April 2019 and used single-season occupancy models and Royle-Nichols abundance estimation models to analyze our data. We recorded 21 species of mammals, including the first sighting of jaguar (Panthera onca) in this region in 25 years. River characteristics (distance from river, riparian corridor width, water availability), remoteness (distance from highway, productivity, elevation), and topographic variety (vertical elevation difference) influenced patterns of occupancy probability and estimated abundance of mammals >1 kg, but the strength and direction of these relationships varied by species. Additionally, intermittently wet desert washes were comparable in species richness to the perennial system. These results highlight the importance of examining physical and biological aspects of habitat. This is especially true when identifying corridors where mitigation structures should be placed to improve wildlife connectivity in biodiversity hotspots like the Madrean Archipelago and semi-arid ecosystems worldwide. 相似文献
54.
The aims of this study were to investigate the diet and relative abundance of fruit bats in a lowland Malaysian rain forest and to test the hypothesis that the local assemblage structure of fruit bats varies significantly over time in relation to the availability of food. In total, 352 fruit bats of eight species were captured during 72,306 m2 mist‐net hours of sampling between February 1996 and September 1999. Three species of fruit bats (Balionycteris maculita, Chironax melanocephalus, and Cynopterus brachyotis) that fed on a wide range of “steady state” and “big bang” food resources were captured continuously throughout the study period, with no significant variation in capture rates over time. In contrast, five species that fed exclusively or almost exclusively on “big bang” food resources were sampled intermittently, with significant temporal variation in the capture rates of two species (Cynopterus horsfieldi and Megaerops ecaudatus). Significant variation in the capture rates of the remaining three species (Dyacopterus spadiceus, Eonycteris spelaea, and Rousettus amplexicaudatus) could not be detected due to small sample sizes. Since ephemeral “big bang” food resources were only sporadically available within the study area and were associated with large canopy trees and strangler figs, these results suggest that food abundance, or the availability of specific food items, may be important factors limiting local fruit bat species diversity in old‐growth Paleotropical rain forest. Thus, only three fruit bat species were locally resident within the forest throughout the study period. Therefore, further studies on the ranging behavior and habitat requirements of Malaysian fruit bats are required to assess the adequacy of existing reserves and protected areas. 相似文献
55.
Sharon L. Gursky 《International journal of primatology》1995,16(1):843-853
I present quantitative and qualitative data on infant caretaking behaviors collected during a preliminary field study of spectral
tarsiers (Tarsius spectrum),in a northern Sulawesi rain forest. The primary goal of the study is to identify the basic pattern of infant care in this
species. I studied tarsiers at Tangkoko-Dua Saudara Nature Reserve in Sulawesi, Indonesia, from May to July 1992. I observed
two infants, from two groups for a total of 96 hr using focal follows. During individual focal follows, ranging from 20 min
to 6 hr, I recorded behaviors at 5-min intervals. I also recorded distances of group members relative to the infant at 5-min
intervals. I subsampled the data at 35-min intervals to control for statistical autocorrelation between data points. Infants
were alone between 40 and 50% of the time. The two subadults were more frequently in proximity to the infant than the adult
males, the nonmatemal adult female, or the mothers were. This pattern of the subadults maintaining proximity to the infant
continued when the mothers were absent. These results suggest that subadults may be guarding or babysitting infants. It is
also possible that subadults are not traveling as far from the sleeping site as adults do and are therefore more likely to
be found in association with the infant. 相似文献
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59.
Sublocalization of an Ataxia-Telangiectasia Gene Distal to D11S384 by Ancestral Haplotyping In Costa Rican Families 总被引:8,自引:4,他引:4 下载免费PDF全文
Nancy Uhrhammer Ethan Lange Oscar Porras Arash Naeim Xiaoguang Chen Sepideh Sheikhavandi Sujata Chiplunkar Lan Yang Sugandha Dandekar Teresa Liang Nima Patel Sharon Teraoka Nitin Udar Nidia Calvo Patrick Concannon Kenneth Lange Richard A. Gatti 《American journal of human genetics》1995,57(1):103-111
In an effort to localize a gene for ataxia-telangiectasia (A-T), we have genotyped 27 affected Costa Rican families, with 13 markers, in the chromosome 11q22-23 region. Significant linkage disequilibrium was detected for 9/13 markers between D11S1816 and D11S1391. Recombination events observed in these pedigrees places A-T between D11S1819 and D11S1960. One ancestral haplotype is common to 24/54 affected chromosomes and roughly two-thirds of the families. Inferred (ancestral) recombination events involving this common haplotype in earlier generations suggest that A-T is distal to D11S384 and proximal to D11S1960. Several other common haplotypes were identified, consistent with multiple mutations in a single gene. When considered together with all other evidence, this study further sublocalizes the major A-T locus to ≈200 kb, between markers S384 and S535. 相似文献
60.
The lung is a highly branched fluid-filled structure, that develops by repeated dichotomous branching of a single bud off the foregut, of epithelium invaginating into mesenchyme. Incorporating the known stress response of developing lung tissues, we model the developing embryonic lung in fluid mechanical terms. We suggest that the repeated branching of the early embryonic lung can be understood as the natural physical consequence of the interactions of two or more plastic substances with surface tension between them. The model makes qualitative and quantitative predictions, as well as suggesting an explanation for such observed phenomena as the asymmetric second branching of the embryonic bronchi. 相似文献