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91.
Savanna chimpanzees are known to re-use areas of the landscape for sleep, and patterns of chimpanzee sleeping site re-use are proposed as a referential model for early hominin archaeological site formation. We recorded the prevalence of deformed but healed branches and remnants of dead branches found around fresh nests at the savanna site of Issa in Ugalla, Tanzania. These old nest scars were found in 79% of 112 beds. We also randomly selected potential nesting locations for a subset of 32 beds within the same trees, and found nest scars in only 19% of these “control” locations. We then monitored 275 nests for up to 19 months for decay, regeneration of new branches, and re-use. Of these 275 nest locations, 24% were re-used within the first nine months of monitoring, and most re-use occurred when the nest had already decayed and was not easily visible from the ground. After 18 months, the proportion of specific nest positions re-used increased to 48%. This fidelity is likely a result of the creation of ideally-shaped support structures and supple new growth for mattress material with successive use of nest locations. We propose that specific nest site re-use may not be a direct product of environmental determination, but a result of “niche construction” through formation of good building sites within trees. Environmental modification through construction behaviour may have influenced both chimpanzee and early hominin ranging, and thus leaves behind recognisable patterns of artefact deposition across the landscape. 相似文献
92.
93.
Erik F. J. Weenink Hans C. P. Matthijs J. Merijn Schuurmans Tim Piel Maria J. van Herk Corrien A. M. Sigon Petra M. Visser Jef Huisman 《Environmental microbiology》2021,23(5):2404-2419
Oceanographic studies have shown that heterotrophic bacteria can protect marine cyanobacteria against oxidative stress caused by hydrogen peroxide (H2O2). Could a similar interspecific protection play a role in freshwater ecosystems? In a series of laboratory experiments and two lake treatments, we demonstrate that freshwater cyanobacteria are sensitive to H2O2 but can be protected by less-sensitive species such as green algae. Our laboratory results show that green algae degrade H2O2 much faster than cyanobacteria. Consequently, the cyanobacterium Microcystis was able to survive at higher H2O2 concentrations in mixtures with the green alga Chlorella than in monoculture. Interestingly, even the lysate of destructed Chlorella was capable to protect Microcystis, indicating a two-component H2O2 degradation system in which Chlorella provided antioxidant enzymes and Microcystis the reductants. The level of interspecific protection provided to Microcystis depended on the density of Chlorella. These findings have implications for the mitigation of toxic cyanobacterial blooms, which threaten the water quality of many eutrophic lakes and reservoirs worldwide. In several lakes, H2O2 has been successfully applied to suppress cyanobacterial blooms. Our results demonstrate that high densities of green algae can interfere with these lake treatments, as they may rapidly degrade the added H2O2 and thereby protect the bloom-forming cyanobacteria. 相似文献
94.
Peter Sörös Faisal Al-Otaibi Savio WH Wong J Kevin Shoemaker Seyed M Mirsattari Vladimir Hachinski Ruth E Martin 《BMC neurology》2011,11(1):20
Background
Various functional resonance imaging, magnetoencephalographic and lesion studies suggest the involvement of the insular cortex in the control of swallowing. However, the exact location of insular activation during swallowing and its functional significance remain unclear. 相似文献95.
P Maiuri E Terriac P Paul-Gilloteaux T Vignaud K McNally J Onuffer K Thorn PA Nguyen N Georgoulia D Soong A Jayo N Beil J Beneke JC Hong Lim C Pei-Ying Sim YS Chu;WCR participants A Jiménez-Dalmaroni JF Joanny JP Thiery H Erfle M Parsons TJ Mitchison WA Lim AM Lennon-Duménil M Piel M Théry 《Current biology : CB》2012,22(17):R673-R675
Motility is a common property of animal cells. Cell motility is required for embryogenesis [1], tissue morphogenesis [2] and the immune response [3] but is also involved in disease processes, such as metastasis of cancer cells [4]. Analysis of cell migration in native tissue in vivo has yet to be fully explored, but motility can be relatively easily studied in vitro in isolated cells. Recent evidence suggests that cells plated in vitro on thin lines of adhesive proteins printed onto culture dishes can recapitulate many features of in vivo migration on collagen fibers [5,6]. However, even with controlled in vitro measurements, the characteristics of motility are diverse and are dependent on the cell type, origin and external cues. One objective of the first World Cell Race was to perform a large-scale comparison of motility across many different adherent cell types under standardized conditions. To achieve a diverse selection, we enlisted the help of many international laboratories, who submitted cells for analysis. The large-scale analysis, made feasible by this competition-oriented collaboration, demonstrated that higher cell speed correlates with the persistence of movement in the same direction irrespective of cell origin. 相似文献
96.
Marine sponges (phylum Porifera) often contain dense and diverse microbial communities, which can constitute up to 35% of the sponge biomass. The genome of one sponge, Amphimedon queenslandica, was recently sequenced, and this has provided new insights into the origins of animal evolution. Complementary efforts to sequence the genomes of uncultivated sponge symbionts have yielded the first glimpse of how these intimate partnerships are formed. The remarkable microbial and chemical diversity of the sponge-microorganism association, coupled with its postulated antiquity, makes sponges important model systems for the study of metazoan host-microorganism interactions, and their evolution, as well as for enabling access to biotechnologically important symbiont-derived natural products. In this Review, we discuss our current understanding of the interactions between marine sponges and their microbial symbiotic consortia, and highlight recent insights into these relationships from genomic studies. 相似文献
97.
Sessile marine animals like sponges, tunicates, and bryozoans are a rich source of bioactive natural products, many of which
exhibit potent anticancer activities. However, most of these substances are available in very limited amounts only, which
has prohibited further drug development. Recent evidence suggests that symbiotic bacteria might be the true producers of many
animal-derived metabolites. In addition to revealing fascinating perspectives for research in marine chemical ecology, these
findings suggest new solutions to the supply problem. Although most symbionts remain uncultivated, bacterial production systems
might be created by isolating biosynthetic genes from marine metagenomes, and expressing them in culturable bacterial hosts.
This review discusses cell-sorting, natural product visualization, and phylogenetic approaches to identify symbiotic producers.
In addition, strategies to isolate genes and gene clusters from marine species consortia are described. These techniques have
provided insights into the bacterial origin and biosynthesis of polyketides like the onnamides, swinholides, and bryostatins,
of peptides including the patellamides, chlorinated dipeptides, and theopalauamide as well as of brominated biphenylethers. 相似文献
98.
Although several studies reported a significant effect with regard to the gender difference in an interest in dreams, the generalizability of these studies is limited because mainly students were recruited as participants. In this study, gender differences with regard to interest in dream interpretation as an indicator of interest in dreams in general have been demonstrated in a representative sample. There was, however, a significant age-gender interaction, indicating that interest in dreams might not be a potent variable for explaining gender differences in dream recall. In future studies, the course of interest in dreams over the life span and any associated gender differences should be investigated using carefully designed scales. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
99.
D Montoya C Arévalo S Gonzales F Aristizabal WH Schwarz 《Journal of industrial microbiology & biotechnology》2001,27(5):329-335
Thirteen new Clostridium strains, previously isolated from soil and found to produce high amounts of solvents from glucose, hydrolyzed a great variety
of α- and β-glycans, including raw starch, xylan, pectin, inulin and cellulose. The sequences of the PCR-amplified DNA fragments
containing the variable 3′ part of one of the 16S rRNA genes were 99.5% identical. The macrorestriction pattern of two endonucleolytic
digests of chromosomal DNA in the pulsed-field gel electrophoresis (PFGE) confirmed their high homogeneity on the DNA level.
The complete 16S rRNA gene sequence of three selected strains was 99.8% identical to the 16S rRNA gene sequence from Clostridium butyricum and separates them from C. acetobutylicum. To the closely related four species of solventogenic clostridia a new group of strains has to be added, which has a great
potential for the direct fermentation of biomass.
Journal of Industrial Microbiology & Biotechnology (2001) 27, 329–335.
Received 12 September 2000/ Accepted in revised form 25 July 2001 相似文献
100.
Galgani F Piel N Vincent F 《Comparative biochemistry and physiology. Part B, Biochemistry & molecular biology》1999,124(4):699-369
A simplified procedure is described for polymerase chain reaction (PCR) of a partial sequence (bp 601–893) of the plastid gene psbA in the rhodophyte Porphyra linearis and the diatoms Haslea ostreria and Skeletonema costatum. This procedure involves the use of all tissues of P. linearis and live cell suspensions of H. ostreria or S. costatum as DNA templates, without any further purification of DNA. As in the case of PCR with DNA extracts, a single major band of the expected size (292 bp) was obtained after PCR for the three species. Sequences of the amplified fragments were aligned, confirming that the amplified products were part of the psbA gene. The method was then used to screen mutations in partial psbA genes of 23 samples of P. linearis collected at four different stations along the mid-Atlantic coast of France. An alignment was obtained indicating the existence of mutations, though not in codons known for herbicide resistance. All mutations found were silent. However, genetic polymorphism discriminated between samples collected from two stations. The method employed allows rapid amplification of the herbicide target gene and simplifies the procedure for screening mutations or populations in algae. Its application to other genes and species is considered. 相似文献