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21.
Human skin heals more slowly in aged vs. young adults, but the mechanism for this delay is unclear. In humans, eccrine sweat glands (ESGs) and hair follicles underlying wounds generate cohesive keratinocyte outgrowths that expand to form the new epidermis. Here, we compared the re‐epithelialization of partial‐thickness wounds created on the forearm of healthy young (< 40 yo) and aged (> 70 yo) adults. Our results confirm that the outgrowth of cells from ESGs is a major feature of repair in young skin. Strikingly, in aged skin, although ESG density is unaltered, less than 50% of the ESGs generate epithelial outgrowths during repair (vs. 100% in young). Surprisingly, aging does not alter the wound‐induced proliferation response in hair follicles or ESGs. Instead, there is an overall reduced cohesiveness of keratinocytes in aged skin. Reduced cell–cell cohesiveness was most obvious in ESG‐derived outgrowths that, when present, were surrounded by unconnected cells in the scab overlaying aged wounds. Reduced cell–cell contact persisted during the repair process, with increased intercellular spacing and reduced number of desmosomes. Together, reduced outgrowths of ESG (i) reduce the initial number of cells participating in epidermal repair, (ii) delay wound closure, and (iii) lead to a thinner repaired epidermis in aged vs. young skin. Failure to form cohesive ESG outgrowths may reflect impaired interactions of keratinocytes with the damaged ECM in aged skin. Our findings provide a framework to better understand the mediators of delayed re‐epithelialization in aging and further support the importance of ESGs for the repair of human wounds.  相似文献   
22.
The sensory drive hypothesis proposes that environmental factors affect both signalling dynamics and the evolution of signals and receivers. Sound detection and equilibrium in marine fishes are senses dependent on the sagittae otoliths, whose morphological variability appears intrinsically linked to the environment. The aim of this study was to understand if and which environmental factors could be conditioning the evolution of this sensory structure, therefore lending support to the sensory drive hypothesis. Thus, we analysed the otolith shape of 42 rockfish species (Sebastes spp.) to test the potential associations with the phylogeny, biological (age), ecological (feeding habit and depth distribution) and biogeographical factors. The results showed strong differences in the otolith shapes of some species, noticeably influenced by ecological and biogeographical factors. Moreover, otolith shape was clearly conditioned by phylogeny, but with a strong environmental effect, cautioning about the use of this structure for the systematics of rockfishes or other marine fishes. However, our most relevant finding is that the data supported the sensory drive hypothesis as a force promoting the radiation of the genus Sebastes. This hypothesis holds that adaptive divergence in communication has significant influence relative to other life history traits. It has already been established in Sebastes for visual characters and organs; our results showed that it applies to otolith transformations as well (despite the clear influence of feeding and depth), expanding the scope of the hypothesis to other sensory structures.  相似文献   
23.

Background  

Impairment of cilia and flagella function underlies a growing number of human genetic diseases. Mutations in hydin in hy3 mice cause lethal communicating hydrocephalus with early onset. Hydin was recently identified as an axonemal protein; however, its function is as yet unknown.  相似文献   
24.
Protein quality was assayed by simultaneous measurement of lysine (Lys), carboxymethyllysine (CML) and lysinoalanine (LAL). GC-FID analysis of N-tert-butyl dimethylsilyl (tBDMSi) derivatives of these amino acids was undertaken. tBDMSi derivates were separated on a CP-SIL 5CB commercially fused silica capillary column (25 m x 0.25 mm i.d., 0.25 microm film thickness) employing a thermal gradient programmed from 200 to 300 degrees C. The identity of tBDMSi derivatives of Lys, CML and LAL was established by GC-MS while FID detection was employed for quantification. Analytical parameters such as linearity (lysine 350-4200 microM, LAL 3-81 microM, CML 16-172 microM), precision (1-13% variation coefficients), accuracy (85-108% average recovery) and limits of detection (lysine 0.4 mg/100 g protein, LAL 5.0 mg/100 g protein, CML 3.4 mg/100 g protein) and quantification (lysine 1.4 mg/100g protein, LAL 15.2 mg/100 g protein, CML 11.2 mg/100 g protein) were determined for validation of the analytical approach. Model systems and real foods have been studied. Kinetic of CML formation from different food proteins (BSA, soy protein, casein and gluten) was performed employing model systems. Carboxymethylation rate depended on the source of protein. Maillard reaction progressed to advanced stages damaging the protein quality of stored infant foods, soy drinks, boiled eggs and dry powdered crepes. CML values ranged from 62 to 440 mg/100 g protein were measured. LAL was also formed during boiling eggs (21-68 mg/100g protein) indicating additional damage by crosslinking reaction. In agreement, lysine content was affected by both food processing and storage.  相似文献   
25.
Farré JC  Vidal J  Subramani S 《Autophagy》2007,3(3):230-234
The cytoplasm-to-vacuole targeting (Cvt) pathway of Saccharomyces cerevisiae delivers aminopeptidase I (Ape1) from the cytosol to the vacuole, bypassing the normal secretory route. The Cvt pathway, although well-studied, was known only in S. cerevisiae. We demonstrate its existence in the methylotrophic yeast, Pichia pastoris, where it also delivers P. pastoris Ape1 (PpApe1) to the vacuole. Most proteins known to be required for the Cvt pathway in S. cerevisiae were, to the extent we found orthologs, also required in P. pastoris. The P. pastoris Cvt pathway differs, however, from that in S. cerevisiae, in that new proteins, such as PpAtg28 and PpAtg26, are involved. The discovery of a Cvt pathway in P. pastoris makes it an excellent model system for the dissection of autophagy-related pathways in a single organism and for the discovery of new Cvt pathway components.  相似文献   
26.
IntroductionPopulation ageing and scientific progress have made specific training in Geriatrics essential for any medical students. There are different international recommendations on the teaching of Geriatric Medicine at undergraduate level, but they are still far from being offered systematically. The aim of this work was to develop a National list of recommendations in order to improve training in Geriatric Medicine at the undergraduate level.Material and methodsA list of 10 recommendations was produced by reflecting on the Geriatric training situation in Spain in 2016/2017 and international recommendations. Consensus was reached among the members of the Spanish Society of Geriatrics and Gerontology (SEGG) working group on «Geriatric training at undergraduate level» through 2 meetings and online discussions.ResultsA list of 10 of recommendations on Geriatric training in Spanish Medical Schools is proposed, including areas such as, the status of the discipline in the curriculum, length, contents, practical training, lecturers, teaching methods, and innovation.ConclusionsThese recommendations are intended to improve Geriatrics training. They can be used by different Medical Schools either to adapt their programs or to start training in Geriatric Medicine.  相似文献   
27.
An increasing number of ethnic minorities are expected to enter the United States workforce based on projected demographic changes. This includes American Indian/Alaskan Native (AI/AN) nurses. Sociocultural influences on sleep disturbances, sleepiness, and other aspects related to shift-work tolerance are of unrecognized importance. More minority nurses are needed to provide culturally congruent care; however, AI/AN nurses represent less than 1% of nurses located throughout the American workforce. This article aims to verify the feasibility of Internet data collection (Web-based survey) methods and instrument stability as the first part of a two-phase study comparing individual differences and shift-work-related sleep disturbances between AI/AN and White non-Hispanic (WNH) nurses. In the first phase, an Internet survey was used to reach a cross-section of AI/AN and WNH nurses. The on-line survey was composed of accepted shift-work-related instruments. Items estimating sleep disturbances, sociocultural choices, time awareness, polychronicity, morningness/eveningness, ethnic identity, and demographic questions were asked. The survey was linked to a series of Web pages describing the study purpose, inclusion and exclusion criteria, consent form, Web survey, and the second phase of the study in which subjects were invited to participate in actigraphy measurements. The survey was pilot-tested for error codes, item confusion, length, and completion time. Forced-answer questions were added asking ethnicity, age group, license type, state where licensed, and legal name on nursing license before accessing the survey. Data were saved periodically, cued by the word “continue.” The database was located on a secure server and password protected. Nurses were recruited using published articles and printed advertisements, hospital e-mail systems, national nursing organization Web sites (minoritynurse.com; NANAINA.org), nursing Web site discussion groups, snow-balling, and word of mouth. The site was accessed 656 times with the Internet survey being completed by 138 WNH and 56 AI/AN nurses meeting the inclusion criteria. Except for the polychronicity measure (PAI3), instruments measuring time awareness, chronotype, and situational sleepiness achieved acceptable reliability coefficients with Internet data collection. Using pull-down menus would improve questions asking specific times. Internet data collection with different ethnic groups is possible; however, accessing the target population may be difficult. Despite extensive recruitment efforts, few AI/AN nurses participated. Computer literacy and failing to relate to the study's purpose may have limited the interest of the AI/AN nurses. It is possible to recruit nurse shift workers and collect individual difference and sleep disturbance data through the Internet; however, the researcher must remain vigilant throughout the process.  相似文献   
28.
The chaperonin GroEL assists protein folding through ATP-dependent, cooperative movements that alternately create folding chambers in its two rings. The substitution E461K at the interface between these two rings causes temperature-sensitive, defective protein folding in Escherichia coli. To understand the molecular defect, we have examined the mutant chaperonin by cryo-EM. The normal out-of-register alignment of contacts between subunits of opposing wild-type rings is changed in E461K to an in-register one. This is associated with loss of cooperativity in ATP binding and hydrolysis. Consistent with the loss of negative cooperativity between rings, the cochaperonin GroES binds simultaneously to both E461K rings. These GroES-bound structures were unstable at higher temperature, dissociating into complexes of single E461K rings associated with GroES. Lacking the allosteric signal from the opposite ring, these complexes cannot release their GroES and become trapped, dead-end states.  相似文献   
29.
The coelomycetous genera Chaetomella and Pilidium were determined to be closely related to each other, yet are recognized as distinct genera based on both morphological observations and rDNA sequence analyses. Analyses of the SSU and LSU of the nuclear ribosomal RNA genes suggest that Chaetomella and Pilidium along with Sphaerographium tenuirostrum and Synchaetomella lunatospora constitute a distinct lineage within the ascomycetes that is allied with the Leotiomycetes. Chaetomella and Pilidium both produce black pycnidia generally opening by a raphe, acropleurogenous conidiogenous cells, and non-septate, hyaline, usually fusiform to falcate, rarely ellipsoid, conidia. Pycnidia of Pilidium are smooth while those of Chaetomella have setae of various types. A Hainesia sporodochial synanamorph was observed in cultures of C. oblonga and C. raphigera similar to H. lythri, the synanamorph of P. concavum. Specimens of C. oblonga, type species of Chaetomella, C. acutiseta, C. circinoseta, C. raphigera, Pilidium acerinum, type species of Pilidium, and P. concavum were examined. Diagnoses and illustrations are provided for these species along with a key to the accepted species in both genera. Mention of trade names or commercial products in this article is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture.  相似文献   
30.

Background  

In addition to known protein-coding genes, large amounts of apparently non-coding sequence are conserved between the human and mouse genomes. It seems reasonable to assume that these conserved regions are more likely to contain functional elements than less-conserved portions of the genome.  相似文献   
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