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Lintsi M Kaarma H 《Anthropologischer Anzeiger; Bericht über die biologisch-anthropologische Literatur》2003,61(4):435-443
An anthropometric study of 552 Tartu city and Tartu county recruits aged 17 years was carried out. Height and weight, 33 anthropometric measurements and 12 skinfolds were measured. Body fat percentage was assessed by Omron BF 300 hand-held segmental body fat analyzer. From anthropometric measurements bone mass was derived by the Drink-water et al. (1986) equation, and total skeletal muscle mass by the Lee et al. (2000) equation. The data were systematized into five height-weight SD-classes. There were 3 classes with harmony between height and weight class: 1--small (small height and small weight), 2--medium (medium height and medium weight), 3--large (large height and large weight), 4--weight class dominating (pyknomorphic) and 5--height class dominating (leptomorphic). It was revealed that in classes 1, 2 and 3 the height and weight increase corresponded to the increase in all heights, breadths and depths, circumferences, skinfolds, body fat, muscle and bone mass. In class 4 circumferences, skinfolds, body fat and muscle mass were bigger. In class 5 all heights and the relative bone mass were bigger. The present investigation confirms the hypothesis that the five height-weight class system is applicable to seventeen-year-old recruits. 相似文献
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The study of gene functions requires the development of a DNA library of high quality through much of testing and screening. Pooling design is a mathematical tool to reduce the number of tests for DNA library screening. The transversal design is a special type of pooling design, which is good in implementation. In this paper, we present a new construction for transversal designs. We will also extend our construction to the error-tolerant case. 相似文献
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Reliably producing functional in vitro organ models, such as organ-on-chip systems, has the potential to considerably advance biology research, drug development time, and resource efficiency. However, despite the ongoing major progress in the field, three-dimensional bone tissue models remain elusive. In this review, we specifically investigate the control of perfusion flow effects as the missing link between isolated culture systems and scientifically exploitable bone models and propose a roadmap toward this goal. 相似文献
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Myrsini Michou Angelos Stergios Georgios Skretas 《Biotechnology and bioengineering》2020,117(8):2434-2445
The bacterium Escherichia coli is among the most popular hosts for recombinant protein production, including that of membrane proteins (MPs). We have recently generated the specialized MP-producing E. coli strain SuptoxD, which upon co-expression of the effector gene djlA, is capable of alleviating two major bottlenecks in bacterial recombinant MP production: it suppresses the toxicity that frequently accompanies the MP-overexpression process and it markedly increases the cellular accumulation of membrane incorporated and properly folded recombinant MP. Combined, these two positive effects result in dramatically enhanced volumetric yields for various recombinant MPs of both prokaryotic and eukaryotic origin. Based on the observation that djlA is found in the genomes of various pathogenic bacteria, the aim of the present work was to investigate (a) whether other naturally occurring DjlA variants can exert the MP toxicity-suppressing and production-promoting effects similarly to the E. coli DjlA and (b) if we can identify a DjlA variant whose efficiency surpasses that of the E. coli DjlA of SuptoxD. We report that a quite surprisingly broad variety of homologous DjlA proteins exert beneficial effects on recombinant MP when overexpressed in E. coli. Furthermore, we demonstrate that the Salmonella enterica DjlA is an even more potent enhancer of MP productivity compared with the E. coli DjlA of SuptoxD. Based on this, we constructed a second-generation SuptoxD strain, termed SuptoxD2.0, whose MP-production capabilities surpass significantly those of the original SuptoxD, and we anticipate that SuptoxD2.0 will become a broadly utilized expression host for recombinant MP production in bacteria. 相似文献
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The lateral diffusion of the excimer-forming probe pyrene decanoic acid has been determined in erythrocyte membranes and in vesicles of the lipid extracts. The random walk of the probe molecules is characterized by their jump frequency, vj, within the lipid matrix. At T = 35°C a value of vj = 1.6 · 103 s?1 is found in erythrocyte membranes. A somewhat slower mobility is determined in vesicles prepared from lipid extracts of the erythrocyte membrane. Depending on structure and charge of the lipids we obtain jump frequencies between 0.8 · 108 s?1 and 1.5 · 108 s?1 at T = 35°C. The results are compared with jump frequencies yielded in model membranes.The mobility of molecules perpendicular to the membrane surface (transversal diffusion) is investigated. Erythrocyte ghosts doped with pyrene phosphatidylcholine were mixed with undoped ghosts in order to study the exchange kinetics of the probe molecule. A fast transfer between the outer layers of the ghost cells () is found. The exchange process between the inner and the outer layer of one erythrocyte ghost (flip-flop process) following this fast transfer occurs with a half-life time value of .The application of excimer-forming probes presumes a fluid state of the membrane. Therefore we investigated the phase transition behaviour using the excimer technique. Beside a thermotropic phase transition at T = 23°C and T = 33°C we observed an additional fluidity change at T = 38°C in erythrocyte ghosts. This transition is attached to a separation of the boundary lipid layer from the intrinsic proteins. No lipid phase transition is observed in liposomes from isolated extracts of the erythrocyte membrane with our methods. 相似文献
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Over the last decade, chemo-radiotherapy represented a well-established paradigm for cancer treatment. Developing new strategies to promote the therapeutic efficacy while reducing toxic side effects of chemo-radiotherapy is a main research objective in cancer therapy. A promising new oncological strategy for enhancing chemo-radiotherapy against cancer involves the utilization of multifunctional nanoparticles (nanocarriers and radiosensitizers). In this work, Chitosan-Capped Gold Nanoparticles (CS-GNPs) were synthesized and loaded with an anticancer agent, Doxorubicin (CS-GNPs-DOX). The prepared multifunctional nano-formulation acted as nano-radiosensitizer, in addition to being an intrinsic drug delivery system allowing efficient loading and targeting of chemotherapeutics. The therapeutic efficacy of CS-GNPs-DOX was studied by treating breast cancer cells (MCF-7) with CS-GNPs-DOX accompanied by different doses of X-rays (0.5, 1 and 3 Gy) and assessing the cytotoxic effect via neutral red cell viability assay. Further assessment of the therapeutic efficacy was conducted using flowcytometry to measure the induction of apoptosis, while neutral comet assay was carried out to check DNA double strand breaks. Results showed that CS-GNPs-DOX could enhance the chemo-radiotherapeutic effect by significantly decreasing cancer cells viability with increasing DNA double strand breaks and inducing cell necrosis even at a very low radiation dose (0.5 Gy). Interestingly, the developed multifunctional CS-GNPs-DOX provided a synergistic regimen for cancer treatment that effectively delivered DOX to tumor cells and enhanced the radiosensitization activity, thus minimizing conventional radio-therapeutic required doses. Accordingly, CS-GNPs-DOX represents a promising multifunctional nanoparticle for enhancing breast cancer chemo-radiotherapy. 相似文献
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Anna?Aiello Giulia?Accardi Giuseppina?Candore Giuseppe?Carruba Sergio?Davinelli Giuseppe?Passarino Giovanni?Scapagnini Sonya?Vasto Calogero?Caruso
During the last two centuries the average lifespan has increased at a rate of approximately 3 months/year in both sexes, hence oldest old people are becoming the population with the fastest growth in Western World. Although the average life expectancy is increasing dramatically, the healthy lifespan is not going at the same pace. This underscores the importance of studies on the prevention of age-related diseases, in order to satisfactorily decrease the medical, economic and social problems associated to advancing age, related to an increased number of individuals not autonomous and affected by invalidating pathologies. In particular, data from experimental studies in model organisms have consistently shown that nutrient signalling pathways are involved in longevity, affecting the prevalence of age-related loss of function, including age-related diseases. Accordingly, nutrigerontology is defined as the scientific discipline that studies the impact of nutrients, foods, macronutrient ratios, and diets on lifespan, ageing process, and age-related diseases. To discuss the potential relevance of this new science in the attainment of successful ageing and longevity, three original studies performed in Sicily with local foods and two reviews have been assembled in this series. Data clearly demonstrate the positive effects of nutraceuticals, functional foods and Mediterranean Diet on several biological parameters. In fact, they could represent a prevention for many age-related diseases, and, although not a solution for this social plague, at least a remedy to alleviate it. Thus, the possibility to create a dietary pattern, based on the combined strategy of the use of both nutraceuticals and functional foods should permit to create a new therapeutic strategy, based not only on a specific bioactive molecule or on a specific food but on a integrated approach that, starting from the local dietary habits, can be led to a “nutrafunctional diet” applicable worldwide. 相似文献
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Robustness, the insensitivity of some of a biological system's functionalities to a set of distinct conditions, is intimately linked to fitness. Recent studies suggest that it may also play a vital role in enabling the evolution of species. Increasing robustness, so is proposed, can lead to the emergence of evolvability if evolution proceeds over a neutral network that extends far throughout the fitness landscape. Here, we show that the design principles used to achieve robustness dramatically influence whether robustness leads to evolvability. In simulation experiments, we find that purely redundant systems have remarkably low evolvability while degenerate, i.e. partially redundant, systems tend to be orders of magnitude more evolvable. Surprisingly, the magnitude of observed variation in evolvability can neither be explained by differences in the size nor the topology of the neutral networks. This suggests that degeneracy, a ubiquitous characteristic in biological systems, may be an important enabler of natural evolution. More generally, our study provides valuable new clues about the origin of innovations in complex adaptive systems. 相似文献
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Increasing the production of overproducing strains represents a great challenge. Here, we develop a modular modulation method to determine the key steps for genetic manipulation to increase metabolite production. The method consists of three steps: (i) modularization of the metabolic network into two modules connected by linking metabolites, (ii) change in the activity of the modules using auxiliary rates producing or consuming the linking metabolites in appropriate proportions and (iii) determination of the key modules and steps to increase production. The mathematical formulation of the method in matrix form shows that it may be applied to metabolic networks of any structure and size, with reactions showing any kind of rate laws. The results are valid for any type of conservation relationships in the metabolite concentrations or interactions between modules. The activity of the module may, in principle, be changed by any large factor. The method may be applied recursively or combined with other methods devised to perform fine searches in smaller regions. In practice, it is implemented by integrating to the producer strain heterologous reactions or synthetic pathways producing or consuming the linking metabolites. The new procedure may contribute to develop metabolic engineering into a more systematic practice. © 2015 American Institute of Chemical Engineers Biotechnol. Prog., 31:656–667, 2015 相似文献
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Gong XQ Chang S Zhang QH Li CH Shen LZ Ma XH Wang MH Liu B He HQ Chen WZ Wang CX 《Proteins》2007,69(4):859-865
Protein-protein docking is usually exploited with a two-step strategy, i.e., conformational sampling and decoy scoring. In this work, a new filter enhanced sampling scheme was proposed and added into the RosettaDock algorithm to improve the conformational sampling efficiency. The filter term is based on the statistical result that backbone hydrogen bonds in the native protein structures are wrapped by more than nine hydrophobic groups to shield them from attacks of water molecules (Fernandez and Scheraga, Proc Natl Acad Sci USA 2003;100:113-118). A combinatorial scoring function, ComScore, specially designed for the other-type protein-protein complexes was also adopted to select the near native docked modes. ComScore was composed of the atomic contact energy, van der Waals, and electrostatic interaction energies, and the weight of each item was fit through the multiple linear regression approach. To analyze our docking results, the filter enhanced sampling scheme was applied to targets T12, T20, and T21 after the CAPRI blind test, and improvements were obtained. The ligand least root mean square deviations (L_rmsds) were reduced and the hit numbers were increased. ComScore was used in the scoring test for CAPRI rounds 9-12 with good success in rounds 9 and 11. 相似文献
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Aims: To evaluate and compare remineralisation of root caries lesions after in vitro treatment with various fluoride (F) agents using an Electric Caries Monitor (ECM) and Transversal Micro‐Radiography (TMR). Materials: Permanent human teeth were extracted and root surface specimens were sectioned, prepared (n = 35), and randomly allocated into seven different experimental groups (groups 1–7). Methods: Root surfaces were demineralised in an acidified gel (pH = 5.0) for 3 weeks followed by various F treatments and stored in a standardised remineralising solution at 37°C for 6 weeks. The root surfaces were treated twice daily with different dentifrice slurries for 2 min, either with a neutral placebo dentifrice without F (group 5); or a neutral sodium fluoride (NaF) 1400 p.p.m. F dentifrice (group 1); or a neutral 1250 p.p.m. F dentifrice (group 6); or an acid dentifrice (pH 4.7) with 1400 p.p.m. F containing amine fluoride (AmF) (groups 3 and 4) or a 1250 p.p.m. (pH 4.7) AmF dentifrice (group 6). In groups 1, 2, 5, 6, and 7, the root surfaces were additionally rinsed for 2 min with a neutral non‐F placebo solution. In groups 3 and 4, rinsing were performed for 2 min with an acid (pH 4.7) 250 p.p.m. F solution, containing 125 p.p.m. F as AmF and 125 p.p.m. F as potassium fluoride (KF), once or twice per day respectively. ECM was used to measure electrical resistance on root surfaces at baseline and after 3 and 6 weeks respectively. TMR technique was used to measure and compare root surface lesion depths and mineral loss. Results: Six weeks daily treatment with a dentifrice slurry containing AmF followed by rinsing with a combination of equal amounts of AmF and KF solution twice a day showed a statistical significant higher ECM values compared with the other groups. TMR data measuring lesion depths and mineral loss reduction supported the results of the ECM findings. Conclusions: Daily application of a dentifrice slurry containing 1400 p.p.m. F as AmF combined with twice daily rinsing with a 250 p.p.m. F solution containing equal amount of AmF and KF significantly remineralise primary root caries lesions in vitro. ECM and TMR are valuable complementary methods in order to analyse the remineralisation processes. 相似文献
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Strategies for achieving high-level expression of genes in Escherichia coli. 总被引:35,自引:0,他引:35
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S C Makrides 《Microbiological reviews》1996,60(3):512-538
Progress in our understanding of several biological processes promises to broaden the usefulness of Escherichia coli as a tool for gene expression. There is an expanding choice of tightly regulated prokaryotic promoters suitable for achieving high-level gene expression. New host strains facilitate the formation of disulfide bonds in the reducing environment of the cytoplasm and offer higher protein yields by minimizing proteolytic degradation. Insights into the process of protein translocation across the bacterial membranes may eventually make it possible to achieve robust secretion of specific proteins into the culture medium. Studies involving molecular chaperones have shown that in specific cases, chaperones can be very effective for improved protein folding, solubility, and membrane transport. Negative results derived from such studies are also instructive in formulating different strategies. The remarkable increase in the availability of fusion partners offers a wide range of tools for improved protein folding, solubility, protection from proteases, yield, and secretion into the culture medium, as well as for detection and purification of recombinant proteins. Codon usage is known to present a potential impediment to high-level gene expression in E. coli. Although we still do not understand all the rules governing this phenomenon, it is apparent that "rare" codons, depending on their frequency and context, can have an adverse effect on protein levels. Usually, this problem can be alleviated by modification of the relevant codons or by coexpression of the cognate tRNA genes. Finally, the elucidation of specific determinants of protein degradation, a plethora of protease-deficient host strains, and methods to stabilize proteins afford new strategies to minimize proteolytic susceptibility of recombinant proteins in E. coli. 相似文献
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Karen Ikin Darren S. Le Roux Laura Rayner Nelida R. Villaseñor Kathy Eyles Philip Gibbons Adrian D. Manning David B. Lindenmayer 《Ecological Management & Restoration》2015,16(3):206-214
Australia's urban landscapes offer opportunities to marry socio‐economic and biodiversity conservation objectives. Yet, information is needed on what urban landscape and habitat features are important for wildlife. In this article, we draw together our research from southeastern Australia to describe key lessons for biodiversity‐sensitive cities and towns. Lesson 1: The effects of urbanization on wildlife extend into adjacent habitats. We recommend retaining large, undisturbed areas of habitat away from development, avoiding intensive development adjacent to important conservation areas, prioritizing areas of ecological and social significance, screening light and noise pollution at the urban fringe and around large nature reserves, and planting appropriately provenanced locally native species for public streetscapes, parks and gardens. Lesson 2: Strategic enhancement of urban greenspace offers biodiversity gains. We recommend increasing the total amount of greenspace cover, maintaining ecological structures as habitat islands, using landscaping techniques to minimize risks to human safety, and gardening with low‐flowering native shrubs. Lesson 3: Large old trees need to be managed for long‐term sustainability. We recommend retaining large old trees in new developments, increasing the maximum standing life of urban trees, protecting regenerating areas and planting more seedlings, supplementing habitat features associated with large trees, and ensuring that young trees have space to grow through time. Lesson 4: Education and engagement connects residents with nature and raises awareness. We recommend education programs to enhance opportunities for residents to experience and learn about biodiversity, engaging residents in the establishment and maintenance of wildlife habitat, providing ‘cues to care’, facilitating access to garden plants that benefit wildlife, and encouraging cat containment. These lessons provide an evidence‐base for implementing conservation and management actions to improve the capacity of our cities and towns to support a diverse and abundant biota. 相似文献
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