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Cultivating the uncultured: limits, advances and future challenges   总被引:1,自引:0,他引:1  
Since the invention of the Petri dish, there have been continuous efforts to improve efficiency in microbial cultivation. These efforts were devoted to the attainment for diverse growth conditions, simulation of in situ conditions and achievement of high-throughput rates. As a result, prokaryotes catalysing novel redox reactions as well as representatives of abundant, but not-yet cultured taxa, were isolated. Significant insights into microbial physiology have been made by studying the small number of prokaryotes already cultured. However, despite these numerous breakthroughs, microbial cultivation is still a low-throughput process. The main hindrance to cultivation is likely due to the prevailing lack of knowledge on targeted species. In this review, we focus on the limiting factors surrounding cultivation. We discuss several cultivation obstacles, including the loss of microbial cell–cell communication following species isolation. Future research directions, including the refinement of culture media, strategies based on cell–cell communication and high-throughput innovations, are reviewed. We further propose that a combination of these approaches is urgently required to promote cultivation of uncultured species, thereby dawning a new era in the field.  相似文献   

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Globally, forests are of great economic importance and play a vital role in maintaining friendly ecological environments, sustainability of eco-systems, and biodiversity. Harsh environments, human activities and climate warming have long threatened the diversity of forest genetic resources. Among all conservation strategies, cryopreservation is at present time considered an ideal means for long-term conservation of plant genetic resources. To date, studies on cryopreservation of forest trees have been far behind agricultural and horticultural crops. The present review provides a comprehensive and update information on recent advances in cryopreservation of shoot tips, somatic embryogenic callus and seeds of forest trees. Assessments of genetic stability in the regenerants following cryopreservation were also analyzed and addressed. Further studies on cryopreservation of forest trees are proposed and needed. By doing so, we expect to re-evoke research interests and promote further developments in forest tree cryobiotechnology, thus assisting to ensure maintenance of biodiversity of genetic resources of forest trees.  相似文献   

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Transaminases, which catalyze the stereoselective transfer of an amino group between an amino donor and a prochiral ketone substrate, are interesting biocatalytic tools for the generation of optically pure chiral amines. In particular, amine transaminases (ATAs) are of industrial interest because they are capable of performing reductive amination reactions using a broad range of amine donors and acceptors. The most remarkable example of ATAs industrial application is in the production process of the anti-hyperglycaemic drug sitagliptin (Januvia®/Janumet®), which generated around 6 billion U.S. dollars of revenue to Merck in 2016. In this review, an update about the availability of microbial ATAs, discovered by both screening and database-mining approaches, or obtained by protein engineering of wild-type enzymes, will be provided. Current challenges in ATAs application and possible solutions will be also discussed. In particular, innovative biocatalytic process strategies aimed at the improvement of ATAs performances in chiral amines synthesis, e.g., using in situ product removal process strategies or flow reactors, will be presented. The progress in the industrial exploitation of these enzymes will be highlighted by selected examples of large-scale ATA-catalyzed processes.  相似文献   

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The construct General Sleep-related Experiences (GSEs, such as elevated dream recall, vivid or bizarre dreams, flying dreams, hypnagogic hallucinations, nightmares, and recurrent dreams) has been previously linked to various forms of psychopathology in nonclinical populations. The aim of this pilot study was to explore this relationship in the context of severe psychopathology. Nineteen outpatients of a mental health clinic were compared to 26 controls on sleep experiences, psychopathology, sleep quality, life stress, and transliminality. Outpatients also reported illness intrusiveness levels. As expected, the outpatient group had elevated GSEs. Within the outpatient group, illness intrusiveness, stress, and transliminality were correlated with GSEs. These findings elucidate the association between GSEs and distress in the context of severe psychopathology. (PsycINFO Database Record (c) 2011 APA, all rights reserved)  相似文献   

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Many enzymes are efficiently produced by microbes. However, the use of natural enzymes as biocatalysts has limitations such as low catalytic efficiency, low activity, and low stability, especially under industrial conditions. Many protein engineering technologies have been developed to modify natural enzymes and eliminate these limitations. Commonly used protein engineering strategies include directed evolution, site-directed mutagenesis, truncation, and terminal fusion. This review summarizes recent advances in the molecular engineering of industrial enzymes and discusses future prospects in this field. We expect this review to increase interest in and advance the molecular engineering of industrial enzymes.  相似文献   

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The world''s population is aging, bringing about an ever‐greater burden of mental disorders in older adults. Given multimorbidities, the mental health care of these people and their family caregivers is labor‐intensive. At the same time, ageism is a big problem for older people, with and without mental disorders. Positive elements of aging, such as resilience, wisdom and prosocial behaviors, need to be highlighted and promoted, both to combat stigma and to help protect and improve mental health in older adults. The positive psychiatry of aging is not an oxymoron, but a scientific construct strongly informed by research evidence. We champion a broader concept of geriatric psychiatry – one that encompasses health as well as illness. In the present paper, we address these issues in the context of four disorders that are the greatest source of years lived with disability: neurocognitive disorders, major depression, schizophrenia, and substance use disorders. We emphasize the need for implementation of multidisciplinary team care, with comprehensive assessment, clinical management, intensive outreach, and coordination of mental, physical and social health services. We also underscore the need for further research into moderators and mediators of treatment response variability. Because optimal care of older adults with mental disorders is both patient‐focused and family‐centered, we call for further research into enhancing the well‐being of family caregivers. To optimize both the safety and efficacy of pharmacotherapy, further attention to metabolic, cardiovascular and neurological tolerability is much needed, together with further development and testing of medications that reduce the risk for suicide. At the same time, we also address positive aging and normal cognitive aging, both as an antidote to ageism and as a catalyst for change in the way we think about aging per se and late‐life mental disorders more specifically. It is in this context that we provide directions for future clinical care and research.  相似文献   

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Neuroscience as a distinct discipline or research programme has been a rather recent event in most Chinese universities and in the Chinese Academy of Sciences. However, the last few years have witnessed increased funding and an improved research environment for neuroscience, both of which facilitated an influx of Chinese neuroscientists trained abroad. In this review, we have highlighted some recent research advances made by neuroscientists in China. Based on our own expertise, this review is focused mainly on findings that have contributed to our understanding of the mechanisms underlying brain development, neural plasticity and cognitive processes, and neural degeneration.  相似文献   

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Beinfeld MC 《Life sciences》2003,72(7):747-757
Pro Cholecystokinin (CCK) like other prohormones that pass through the regulated secretory pathway, undergoes a number of post-translational modifications during its biosynthesis including tyrosine sulfation, endoproteolytic cleavages, trimming by carboxypeptidase and c-terminal amidation. This minireview summarizes what is known about this process, what specific enzymes are involved in endocrine and neuronal tumor cells and in mutant and knockout mouse strains. It also points out the major challenges that remain for future research.  相似文献   

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Canales C  Grigg S  Tsiantis M 《Planta》2005,221(6):752-756
Leaves, the plants major photosynthetic organs, form through the activity of groups of pluripotent cells, termed shoot apical meristems (SAMs), located at the growing tips of plants. Leaves develop with a dorso–ventral asymmetry, with the adaxial surface adjacent to the meristem and the abaxial surface developing at a distance from it. Molecular genetic studies have shown that the correct specification of adaxial/abaxial polarity requires communication between the incipient leaf and the meristem, and that the juxtaposition of adaxial/abaxial fates is necessary for lamina outgrowth (Waites and Hudson 1995; McConnell et al. 2001). Over the last few years, a number of factors that control cell fate specification in the apex have been identified. This review will focus on recent advances on distinct but overlapping aspects of leaf development, namely, the transition from meristem to leaf fate and the specification of abaxial/adaxial polarity and its possible role in leaf growth.  相似文献   

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In the urgent search for more effective ways to treat cancer, new extraction methods of taxol from endophytic fungus have demonstrated high potential in increasing the efficiency of taxol extraction for more efficient and sustainable production of taxol and cancer treatment products. This paper summarizes recent advances in taxol-producing endophytic fungi, both in China and abroad, in the following areas: isolation and identification of endophytic fungi types, extraction and detection methods of endophytic taxol in plants, and improved efficiency of the extraction process. With the advancement of science and technology, new techniques in biotechnology, such as fungal strain improvement and recombining technique and microbial fermentation engineering, have increased the extraction yield from taxol-producing fungi, thereby improved the overall efficiency of taxol production.  相似文献   

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Evolutionary biology provides a crucial foundation for medicine and behavioral science that has been missing from psychiatry. Its absence helps to explain slow progress; its advent promises major advances. Instead of offering a new kind of treatment, evolutionary psychiatry provides a scientific foundation useful for all kinds of treatment. It expands the search for causes from mechanistic explanations for disease in some individuals to evolutionary explanations for traits that make all members of a species vulnerable to disease. For instance, capacities for symptoms such as pain, cough, anxiety and low mood are universal because they are useful in certain situations. Failing to recognize the utility of anxiety and low mood is at the root of many problems in psychiatry. Determining if an emotion is normal and if it is useful requires understanding an individual's life situation. Conducting a review of social systems, parallel to the review of systems in the rest of medicine, can help achieve that understanding. Coping with substance abuse is advanced by acknowledging how substances available in modern environments hijack chemically mediated learning mechanisms. Understanding why eating spirals out of control in modern environments is aided by recognizing the motivations for caloric restriction and how it arouses famine protection mechanisms that induce binge eating. Finally, explaining the persistence of alleles that cause serious mental disorders requires evolutionary explanations of why some systems are intrinsically vulnerable to failure. The thrill of finding functions for apparent diseases is evolutionary psychiatry's greatest strength and weakness. Recognizing bad feelings as evolved adaptations corrects psychiatry's pervasive mistake of viewing all symptoms as if they were disease manifestations. However, viewing diseases such as panic disorder, melancholia and schizophrenia as if they are adaptations is an equally serious mistake in evolutionary psychiatry. Progress will come from framing and testing specific hypotheses about why natural selection left us vulnerable to mental disorders. The efforts of many people over many years will be needed before we will know if evolutionary biology can provide a new paradigm for understanding and treating mental disorders.  相似文献   

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A state-of-the-art report is presented on recent progress in selected areas of myodynamics, but also on problems that severely hamper the further development of the discipline. Significant advances have been made in elucidating the force-producing interaction between actin and the myosin-S1-subunit, including the localization of the most probable molecular site of power stroke initiation. Concerning the architecture of the myostructures, strong experimental evidence has accumulated for numerous intra-, inter-, and extramuscular pathways for lateral force transmission in addition to the serial sarcomere-to-sarcomere myotendinous path.

It is shown that contemporary muscle models are inadequate in most respects and lag far behind the requirements an appropriate myodynamic model should fulfil. A similar comment applies to the current approaches designed to solve the myoskeletal indeterminacy problem. These formulations neglect myodynamic properties and do not allow for the implementation of biologically realistic objective functions. The solutions currently obtained are highly unsatisfactory. New research directions to rectify these situations are suggested, also with regard to the identification of subject-specific myodynamic parameters.  相似文献   


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