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171.
It is widely held that many differences among primate species in scapular morphology can be functionally related to differing demands on the shoulder associated with particular locomotor habits. This perspective is largely based on broad scale studies, while more narrow comparisons of scapular form often fail to follow predictions based on inferred differences in shoulder function. For example, the ratio of supraspinous fossa/infraspinous fossa size in apes is commonly viewed as an indicator of the importance of overhead use of the forelimb, yet paradoxically, the African apes, the most terrestrial of the great apes, have higher scapular fossa ratios than the more suspensory orangutan. The recent discovery of several nearly complete early hominin scapular specimens, and their apparent morphological affinities to scapulae of orangutans and gorillas rather than chimpanzees, has led to renewed interest in the comparative analysis of human and extant ape scapular form. To facilitate the functional interpretation of differences in ape scapulae, particularly in regard to relative scapular fossa size, we used electromyography (EMG) to document the activity patterns in all four rotator cuff muscles in orangutans and gibbons, comparing the results with previously published data for chimpanzees. 相似文献
172.
Antti Nyyssölä Ville Pihlajaniemi Riikka Järvinen Saara Mikander Hanna Kontkanen Kristiina Kruus Heikki Kallio Johanna Buchert 《Enzyme and microbial technology》2013,52(4-5):272-278
Isolates from gardening waste compost and 38 culture collection microbes were grown on agar plates at pH 4.0 with the cutinase model substrate polycaprolactone as a carbon source. The strains showing polycaprolactone hydrolysis were cultivated in liquid at acidic pH and the cultivations were monitored by assaying the p-nitrophenyl butyrate esterase activities. Culture supernatants of four strains were analyzed for the hydrolysis of tritiated apple cutin at different pHs. Highest amounts of radioactive hydrolysis products were detected at pHs below 5. The hydrolysis of apple cutin by the culture supernatants at acidic pH was further confirmed by GC–MS analysis of the hydrolysis products. On the basis of screening, the acidic cutinase from Aspergillus niger CBS 513.88 was chosen for heterogeneous production in Pichia pastoris and for analysis of the effects of pH on activity and stability. The recombinant enzyme showed activity over a broad range of pHs with maximal activity between pH 5.0 and 6.5. Activity could be detected still at pH 3.5. 相似文献
173.
Johanna V. Weiss Jeremy A. Rentz Todd Plaia Scott C. Neubauer Melissa Merrill-Floyd Tim Lilburn 《Geomicrobiology journal》2013,30(7-8):559-570
Iron deposits (Fe plaque) on wetland plant roots contain abundant microbial populations, including Fe(II)-oxidizing bacteria (FeOB) that have not been cultured previously. In this study, 4 strains of Fe plaque-associated FeOB were isolated from 4 species of wetland plants. All 4 isolates grew in tight association with Fe-oxides, but did not form any identifiable Fe-oxide structures. All strains were obligate lithotrophic Fe(II)-oxidizers that were microaerobic, and were unable to use other inorganic or organic energy sources. One strain, BrT, was shown to fix 14 CO 2 at a rate consistent with its requirement for total cell carbon. The doubling times for the strains varied between 9.5 and 15.8 hours. The fatty acid methyl ester (FAME) profiles of 2 strains, BrT and CCJ, revealed that 16:0, 15:1 isoG, and 14:0 were dominant fatty acids. Phylogenetic analysis of the 16S rRNA gene indicated that all the strains were Betaproteobacteria. Two of the strains, BrT and Br-1 belong to a new species, Sideroxydans paludicola; a third strain, LD-1, is related to Sideroxydans lithotrophicus, a recently described species of FeOB. The fourth isolate, Ferritrophicum radicicola, represented a new genus in a new order of Betaproteobacteria, the Ferritrophicales. There are no other cultured isolates in this order. A small subunit rRNA gene-based, cultivation-independent analysis of Typha latifolia collected from a wetland revealed terminal restriction fragment profiles (tRFLP) consistent with the presence of these bacteria in the rhizosphere. These novel organisms likely play an important role in Fe(II) oxidation kinetics and Fe cycling within many terrestrial and freshwater environments. 相似文献
174.
Andrew P. Norgan Brian A. Davies Ishara F. Azmi Andreas S. Schroeder Johanna A. Payne Gregory M. Lynch Zhaohui Xu David J. Katzmann 《The Journal of biological chemistry》2013,288(36):26147-26156
The endosomal sorting complexes required for transport (ESCRTs) impact multiple cellular processes including multivesicular body sorting, abscission, and viral budding. The AAA-ATPase Vps4 is required for ESCRT function, and its full activity is dependent upon the co-factor Vta1. The Vta1 carboxyl-terminal Vta1 SBP1 Lip5 (VSL) domain stimulates Vps4 function by facilitating oligomerization of Vps4 into its active state. Here we report the identification of the Vps4 stimulatory element (VSE) within Vta1 that is required for additional stimulation of Vps4 activity in vitro and in vivo. VSE activity is autoinhibited in a manner dependent upon the unstructured linker region joining the amino-terminal microtubule interacting and trafficking domains and the carboxyl-terminal VSL domain. The VSE is also required for Vta1-mediated Vps4 stimulation by ESCRT-III subunits Vps60 and Did2. These results suggest that ESCRT-III binding to the Vta1 microtubule interacting and trafficking domains relieves linker region autoinhibition of the VSE to produce maximal activation of Vps4 during ESCRT function. 相似文献
175.
176.
Yanling Wang Johanna M. FältingCharlotte L. Mattsson Therése E. HolmströmJan Nedergaard 《Experimental cell research》2013
Brown adipose tissue is unusual in that the neurotransmitter norepinephrine influences cell destiny in ways generally associated with effects of classical growth factors: regulation of cell proliferation, of apoptosis, and progression of differentiation. The norepinephrine effects are mediated through G-protein-coupled receptors; further mediation of such stimulation to e.g. Erk1/2 activation is in cell biology in general accepted to occur through transactivation of the EGF receptor (by external or internal pathways). We have examined here the significance of such transactivation in brown adipocytes. Stimulation of mature brown adipocytes with cirazoline (α1-adrenoceptor coupled via Gq), clonidine (α2 via Gi) or CL316243 (β3 via Gs) or via β1-receptors significantly activated Erk1/2. Pretreatment with the EGF receptor kinase inhibitor AG1478 had, remarkably, no significant effect on Erk1/2 activation induced by any of these adrenergic agonists (although it fully abolished EGF-induced Erk1/2 activation), demonstrating absence of EGF receptor-mediated transactivation. Results with brown preadipocytes (cells in more proliferative states) were not qualitatively different. Joint stimulation of all adrenoceptors with norepinephrine did not result in synergism on Erk1/2 activation. AG1478 action on EGF-stimulated Erk1/2 phosphorylation showed a sharp concentration–response relationship (IC50 0.3 µM); a minor apparent effect of AG1478 on norepinephrine-stimulated Erk1/2 phosphorylation showed nonspecific kinetics, implying caution in interpretation of partial effects of AG1478 as reported in other systems. Transactivation of the EGF receptor is clearly not a universal prerequisite for coupling of G-protein coupled receptors to Erk1/2 signalling cascades. 相似文献
177.
178.
Elin Grundberg Eshwar Meduri Johanna?K. Sandling ?sa?K. Hedman Sarah Keildson Alfonso Buil Stephan Busche Wei Yuan James Nisbet Magdalena Sekowska Alicja Wilk Amy Barrett Kerrin?S. Small Bing Ge Maxime Caron So-Youn Shin the Multiple Tissue Human Expression Resource Consortium Mark Lathrop Emmanouil T. Dermitzakis Mark I. McCarthy Timothy D. Spector Jordana T. Bell Panos Deloukas 《American journal of human genetics》2013,93(5):876-890
Epigenetic modifications such as DNA methylation play a key role in gene regulation and disease susceptibility. However, little is known about the genome-wide frequency, localization, and function of methylation variation and how it is regulated by genetic and environmental factors. We utilized the Multiple Tissue Human Expression Resource (MuTHER) and generated Illumina 450K adipose methylome data from 648 twins. We found that individual CpGs had low variance and that variability was suppressed in promoters. We noted that DNA methylation variation was highly heritable (h2median = 0.34) and that shared environmental effects correlated with metabolic phenotype-associated CpGs. Analysis of methylation quantitative-trait loci (metQTL) revealed that 28% of CpGs were associated with nearby SNPs, and when overlapping them with adipose expression quantitative-trait loci (eQTL) from the same individuals, we found that 6% of the loci played a role in regulating both gene expression and DNA methylation. These associations were bidirectional, but there were pronounced negative associations for promoter CpGs. Integration of metQTL with adipose reference epigenomes and disease associations revealed significant enrichment of metQTL overlapping metabolic-trait or disease loci in enhancers (the strongest effects were for high-density lipoprotein cholesterol and body mass index [BMI]). We followed up with the BMI SNP rs713586, a cg01884057 metQTL that overlaps an enhancer upstream of ADCY3, and used bisulphite sequencing to refine this region. Our results showed widespread population invariability yet sequence dependence on adipose DNA methylation but that incorporating maps of regulatory elements aid in linking CpG variation to gene regulation and disease risk in a tissue-dependent manner. 相似文献
179.
Our understanding of the development of intrinsic reproductive isolation is still largely based on theoretical models and thorough empirical studies on a small number of species. Theory suggests that reproductive isolation develops through accumulation of epistatic genic incompatibilities, also known as Bateson–Dobzhansky–Muller (BDM) incompatibilities. We can detect these from marker transmission ratio distortion (TRD) in hybrid progenies of crosses between species or populations, where TRD is expected to result from selection against heterospecific allele combinations in hybrids. TRD may also manifest itself because of intragenomic conflicts or competition between gametes or zygotes. We studied early stage speciation in Arabidopsis lyrata by investigating patterns of TRD across the genome in F2 progenies of three reciprocal crosses between four natural populations. We found that the degree of TRD increases with genetic distance between crossed populations, but also that reciprocal progenies may differ substantially in their degree of TRD. Chromosomes AL6 and especially AL1 appear to be involved in many single- and two-locus distortions, but the location and source of TRD vary between crosses and between reciprocal progenies. We also found that the majority of single- and two-locus TRD appears to have a gametic, as opposed to zygotic, origin. Thus, while theory on BDM incompatibilities is typically illustrated with derived nuclear alleles proving incompatible in hybrid zygotes, our results suggest a prominent role for distortions emerging before zygote formation. 相似文献
180.
Mervi Honkatukia Maria Tuiskula-Haavisto Jesus Arango Jonna Tabell Matthias Schmutz Rudolf Preisinger Johanna Vilkki 《遗传、选种与进化》2013,45(1):31