纳米混悬药物传递系统研究进展

在新药研发过程中,约有40%的药物存在溶解性差的问题,限制了药物的开发与应用。纳米混悬剂是20世纪末发展起来的一种纳米药物传递系统,可增加难溶性药物的溶解度和溶出速率、改变药物的体内药物动力学特征、提高口服生物利用度、安全性和有效性。纳米混悬剂不但适用于水溶性差的药物,而且适用于水溶性、脂溶性均较差的药物,其制备方法主要包括"bottom up"和"top down"两种。本文从纳米混悬剂的特点、理论基础、专利技术及应用等方面对纳米混悬剂的研究进展进行了综述。纳米混悬剂对改善难溶性药物的溶出、吸收,提高难溶性药物的有效性、安全性等方面具有显著优势,且适合工业化生产,已有越来越多的产品问世。纳米混悬技术是未来药物传递系统的发展方向之一,将具有良好的应用前景。     

多肽药物的发展现状

随着生物技术与多肽合成技术的日臻成熟,越来越多的多肽药物被开发并应用于临床。因适应证广、安全性高且疗效显著,多肽药物目前已广泛应用于肿瘤、肝炎、糖尿病、艾滋病等疾病的预防、诊断和治疗,具有广阔的开发前景。简介多肽药物的来源与特点及制备方法,重点综述国内外多肽药物的研发概况、国外近年获准上市的主要多肽药物和我国自主研发并进入临床研究的主要多肽药物,旨在为该类新药的研发提供参考。     

Maßgeschneiderte Mikroorganismen

Tailor‐made microorganisms Microbial diversity provides unlimited resources for the development of novel industrial processes and products. Since the beginning of the 20th century microorganisms have been successfully applied for the large scale production of bio‐based products. In recent years, modern methods of strain development and Synthetic Biology have enabled biotech engineers to design even more sophisticated and tailor‐made microorganisms. These microbes serve industrial processes for the production of bulk chemicals, enzymes, polymers, biofuels as well as plant‐derived ingredients such as Artemisinin in an ecologically and economically sustainable and attractive fashion. In the future, production of advanced biofuels, microbial fuel cells, CO₂ as feedstock and microbial cellulose are research topics as well as challenges of global importance. Continuous efforts in microbiology and biotechnology research will be pivotal for white biotechnology to gain more momentum in transforming the chemical industry towards a knowledge based bio‐economy.     

The changing role of ornamental horticulture in alien plant invasions

The number of alien plants escaping from cultivation into native ecosystems is increasing steadily. We provide an overview of the historical, contemporary and potential future roles of ornamental horticulture in plant invasions. We show that currently at least 75% and 93% of the global naturalised alien flora is grown in domestic and botanical gardens, respectively. Species grown in gardens also have a larger naturalised range than those that are not. After the Middle Ages, particularly in the 18th and 19th centuries, a global trade network in plants emerged. Since then, cultivated alien species also started to appear in the wild more frequently than non‐cultivated aliens globally, particularly during the 19th century. Horticulture still plays a prominent role in current plant introduction, and the monetary value of live‐plant imports in different parts of the world is steadily increasing. Historically, botanical gardens – an important component of horticulture – played a major role in displaying, cultivating and distributing new plant discoveries. While the role of botanical gardens in the horticultural supply chain has declined, they are still a significant link, with one‐third of institutions involved in retail‐plant sales and horticultural research. However, botanical gardens have also become more dependent on commercial nurseries as plant sources, particularly in North America. Plants selected for ornamental purposes are not a random selection of the global flora, and some of the plant characteristics promoted through horticulture, such as fast growth, also promote invasion. Efforts to breed non‐invasive plant cultivars are still rare. Socio‐economical, technological, and environmental changes will lead to novel patterns of plant introductions and invasion opportunities for the species that are already cultivated. We describe the role that horticulture could play in mediating these changes. We identify current research challenges, and call for more research efforts on the past and current role of horticulture in plant invasions. This is required to develop science‐based regulatory frameworks to prevent further plant invasions.     

The roots of pollen analysis: the road to Lennart von Post

In 2016 the 100th birthday of palynology was celebrated: Lennart von Post introduced the scientific discipline in 1916 at lectures in Oslo and Stockholm. However, von Post was not the first to study pollen, and research dates back to the works of Nehemiah Grew and Marcello Malpighi in the late 17th century. Afterwards studies focussed mainly on the role of pollen for plant reproduction, and on pollen morphology. The first scientist who observed fossil pollen was Heinrich Göppert in 1836. However, it was not until the 1890s and 1900s that the study of pollen became a regular component in the reconstruction of past vegetation. Lennart von Post subsequently developed theoretical and practical concepts and methods of pollen analysis, and raised palynology from its infancy into the mature scientific discipline that flourished greatly during the century that followed.     

Oleaginous yeasts for biodiesel: Current and future trends in biology and production

Production of biodiesel from edible plant oils is quickly expanding worldwide to fill a need for renewable, environmentally-friendly liquid transportation fuels. Due to concerns over use of edible commodities for fuels, production of biodiesel from non-edible oils including microbial oils is being developed. Microalgae biodiesel is approaching commercial viability, but has some inherent limitations such as requirements for sunlight. While yeast oils have been studied for decades, recent years have seen significant developments including discovery of new oleaginous yeast species and strains, greater understanding of the metabolic pathways that determine oleaginicity, optimization of cultivation processes for conversion of various types of waste plant biomass to oil using oleaginous yeasts, and development of strains with enhanced oil production. This review examines aspects of oleaginous yeasts not covered in depth in other recent reviews. Topics include the history of oleaginous yeast research, especially advances in the early 20th century; the phylogenetic diversity of oleaginous species, beyond the few species commonly studied; and physiological characteristics that should be considered when choosing yeast species and strains to be utilized for conversion of a given type of plant biomass to oleochemicals. Standardized terms are proposed for units that describe yeast cell mass and lipid production.     

Plant Derived Antimalarial Agents: New Leads and Challenges

New treatments for malaria are urgently needed due to the increasing problem of drug-resistance in malaria parasites. The long-established use of quinine and the more recent introduction of artemisinin and its derivatives as highly effective antimalarials demonstrates that plant species are an important resource for the discovery of new antimalarial agents. Furthermore, many plant species continue to be used in traditional medicines for the treatment of malaria and many people depend on such remedies as they cannot afford and/or do not have access to effective antimalarial drugs. In this paper the potential of plant species to yield new leads to antimalarial drugs will be illustrated with reference to cryptolepine, the main alkaloid present in the species, Cryptolepis sanguinolenta. In addition to this approach, there is currently increasing interest in the use and development of traditional herbal remedies for the treatment of malaria as these may have the potential to provide affordable antimalarial treatment for many who cannot afford the drugs needed to treat chloroquine-resistant Plasmodium falciparum infections. However, little is known with respect to the efficacy and safety of traditional antimalarials and clinical studies are urgently needed to establish their value. Some of the issues pertinent to this area will be briefly reviewed and it is hoped that this will stimulate further discussion and research on this important topic.     

Sustainable coccidiosis control in poultry production: the role of live vaccines

The development of new methods of administering coccidiosis vaccines has facilitated their use in the hatchery and thereby improved prospects for the economic vaccination of broilers. The acquisition of protective immunity to Eimeria species is boosted by further exposure to infection after vaccination. Factors that affect the reproductive efficiency of non-attenuated and attenuated vaccines are considered and the key role that oocyst production plays in establishing and maintaining uniform immunity in a flock of chickens is discussed. In addition to immunisation, a possible advantage to the application of certain vaccines is that their use could repopulate poultry houses with drug-sensitive organisms. Theoretical rotation programmes in which the use of drugs is alternated with that of vaccines are described. Variability of the cross-protective immune response between strains of the same species should be considered during vaccine development and subsequent use. The significance of less common species of Eimeria, not included in all vaccines, also needs to be assessed. An important consideration is the occurrence of pathogens other than Eimeria (such as the bacterium Clostridium) in flocks given coccidiosis vaccines and the methods by which they might be controlled. More research is required into the relationship between bacterial and viral infections of poultry and coccidiosis vaccination. Vaccines need to be developed that are simple to apply and cost effective for use in areas of the world where small-scale poultry production is commonplace. In the near future it is likely that more live vaccines based upon oocysts derived from attenuated strains of Eimeria will be developed but in the longer term vaccines will be based on the selective presentation to the host of specific molecules that can induce protective immunity. This achievement will require significant investment from the private and public sectors, and, if successful, will facilitate the sustainable control of coccidiosis in poultry production.     

Forest biotechnology: Innovative methods, emerging opportunities

Summary The productivity of plantation forests is essential to meet the future world demand for wood and wood products in a sustainable fashion and in a manner that preserves natural stands and biodiversity. Plantation forestry has enormously benefited from development and implementation of improved silvicultural and forest management practices during the past century. A second wave of improvements has been brought about by the introduction of new germplasm developed through genetics and breeding efforts for both hardwood and conifer tree species. Coupled with the genetic gains achieved through tree breeding, the emergence of new biotechnological approaches that span the fields of plant developmental biology, genetic transformation, and discovery of genes associated with complex multigenic traits have added a new dimension to forest tree improvement programs. Significant progress has been made during the past five years in the area of plant regeneration via organogenesis and somatic embryogenesis (SE) for economically important tree species. These advances have not only helped the development of efficient gene transfer techniques, but also have opened up avenues for deployment of new high-performance clonally replicated planting stocks in forest plantations. One of the greatest challenges today is the ability to extend this technology to the most elite germplasm, such that it becomes an, economically feasible means for large-scale production and delivery of improved planting stock. Another challenge will be the ability of the forestry research community to capitalize rapidly on current and future genomics-based elucidation of the underlying mechanisms for important but complex phenotypes. Advancements in gene cloning and genomics technology in forest trees have enabled the discovery and introduction of value-added traits for wood quality and resistance to biotic and abiotic stresses into improved genotypes. With these technical advancements, it will be necessary for reliable regulatory infrastructures and processes to be in place worldwide for testing and release of trees improved through biotechnology. Commercialization of planting stocks, as new varieties generated through clonal propagation and advanced breeding programs or as transgenic trees with high-value traits, is expected in the near future, and these trees will enhance the quality and productivity of our plantation forests.     

Sources of information about botanic gardens and herbaria

Botany is the study of living plants in the garden and the wild and of dead plants in the herbarium and laboratory. The value of a botanic garden for teaching purposes became evident in the 16th century with the founding between 1543 and 1600 of botanic gardens at Pisa, Padua, Florence, Bologna, Leyden, Leipzig, Paris, Montpellier and Heidelberg: indeed most of the major European botanic gardens were founded during this and the next two centuries. Associated with the study of living plants in botanic gardens was the invention of the herbarium by Luca Ghini (1490–1556) and the subsequent making of many private herbaria, out of which have developed the large institutional herbaria, mostly in the 18th and 19th centuries. The continuous enrichment of European gardens by the introduction of new plants resulting from European exploration and colonization created many problems of classification and naming, and so led to the development of taxonomic methods and the adoption of consistent binomial nomenclature for species, following Linnaeus, during the 18th century. The fashion for collecting in the 17th and 18th centuries resulted in the amassing of big private collections which later became the basis of institutional collections. The increase of such public collections by making available material for study from all over the world has, in turn, increased the publications relating to this. Thus the botanic garden and the herbarium, with their associated libraries, have become complementary repositories of botanical information invaluable to the taxonomist, the plant geographer, the economic botanist and the student of evolution. Some useful publications relating to botanic gardens, herbaria and botanical and horticultural collectors are listed.     

Three thousand years of questioning sex determination

Of all the inborn differences that distinguish individual humans, as well as other animals, sex exerts the most far-reaching effects, and the question, what determines it, has been debated throughout history. A discriminating reading of Biblical and Ancient Greek sources reveals surprising insights that are relevant to present-day biology. The material basis of generation was inaccessible until, following the invention of the microscope and the discovery of "spermatic animalcules" in the 17th century, the 19th century witnessed the discovery of the mammalian egg, the nature of sperm, and the process of fertilization. Sex was thought to be determined by external conditions. The 20th century developed the genetics of sex determination. The search for the mammalian testis-determining gene during the last quarter century culminated in the discovery of SRY, soon to be accompanied by non-Y chromosome sex- determining genes. During the same period, data accumulated that testicular differentiation was accompanied by accelerated gonadal growth; subsequently, differences in growth were shown to distinguish early XX from early XY embryos. Other research showed that temperature-dependent sex determination was widely distributed among reptiles, thus illustrating that the mammalian system of sex determination is of recent evolutionary origin, adopted in response to homoiothermy and placentation. The recent discovery that Sry induces cell proliferation in the gonads of fetal mice suggests that the task for the 21st century will be to aim beyond simple genotype/phenotype correlations by unraveling the relationship between genes and epigenetic factors acting on cell growth during development and affecting the phenotype in later life.     

Biotechnology in the 21st century

Although the future is unpredictable, it is highly likely that biotechnology will play a much more visible and significant role in the 21st century than it did in the 20th century. The number and kinds of drugs provided by biotechnology will expand markedly and biotechnology will stand at the center of the oncoming revolution in bioinformatics.     

“艺术的外貌、科学的内涵、使命的担当”——植物园500年来的科研与社会功能变迁(二):科学的内涵

世界植物园500多年来的科研行进轨迹既是整个生物学发展史的一个缩影, 也表现出人类对植物资源发掘与利用, 使之服务于经济与社会发展的不懈追求。从16-17世纪的植物园主要研究药用植物并发掘药物, 到18-20世纪以来从植物分类学逐步拓展至众多植物学分支学科, 进一步发展到当今的植物分子生物学及基因组、代谢组学等等。植物园在长达几个世纪的发展进程中, 其科学研究内涵始终贯穿其中, 既奠定了18世纪植物分类学的根基, 也对18世纪以来许多生物学发现及其理论体系的建立作出了不可磨灭的贡献。同时, 16世纪以来跨大陆、跨地区、跨国家之间的植物引种驯化及其发掘利用与传播深刻改变了世界经济社会格局, 影响了一些国家的兴衰。在近代500多年的植物引种驯化与传播过程中, 植物园发挥了引领作用。本文试图对植物园500年来的科学研究轨迹进行梳理, 展望当今植物园在植物宏观与微观生物学及其大数据时代相关研究领域的发展趋势, 为我国植物园的科研方向提供可借鉴的参考。     

iDNA-Methyl: Identifying DNA methylation sites via pseudo trinucleotide composition

Predominantly occurring on cytosine, DNA methylation is a process by which cells can modify their DNAs to change the expression of gene products. It plays very important roles in life development but also in forming nearly all types of cancer. Therefore, knowledge of DNA methylation sites is significant for both basic research and drug development. Given an uncharacterized DNA sequence containing many cytosine residues, which one can be methylated and which one cannot? With the avalanche of DNA sequences generated during the postgenomic age, it is highly desired to develop computational methods for accurately identifying the methylation sites in DNA. Using the trinucleotide composition, pseudo amino acid components, and a dataset-optimizing technique, we have developed a new predictor called “iDNA-Methyl” that has achieved remarkably higher success rates in identifying the DNA methylation sites than the existing predictors. A user-friendly web-server for the new predictor has been established at http://www.jci-bioinfo.cn/iDNA-Methyl, where users can easily get their desired results. We anticipate that the web-server predictor will become a very useful high-throughput tool for basic research and drug development and that the novel approach and technique can also be used to investigate many other DNA-related problems and genome analysis.     

Exploring the microbial biodegradation and biotransformation gene pool

Similar to the New World explorers of the 16th and 17th century, microbiologists today find themselves at the edge of unknown territory. It is estimated that only 0.1-1% of microorganisms can be cultivated using current techniques; the vastness of microbial lifestyles remains to be explored. Because the microbial metagenome is the largest reservoir of genes that determine enzymatic reactions, new techniques are being developed to identify the genes that underlie many valuable chemical biotransformations carried out by microbes, particularly in pathways for biodegradation of recalcitrant and xenobiotic molecules. Our knowledge of catabolic routes built on research during the past 40 years is a solid basis from which to venture on to the little-explored pathways that might exist in nature. However, it is clear that the vastness of information to be obtained requires astute experimental strategies for finding novel reactions.     

Identification Keys,the “Natural Method,” and the Development of Plant Identification Manuals

The origins of field guides and other plant identification manuals have been poorly understood until now because little attention has been paid to 18th century botanical identification guides. Identification manuals came to have the format we continue to use today when botanical instructors in post-Revolutionary France combined identification keys (step-wise analyses focusing on distinctions between plants) with the “natural method” (clustering of similar plants, allowing for identification by gestalt) and alphabetical indexes. Botanical works featuring multiple but linked techniques to enable plant identification became very popular in France by the first decade of the 19th century. British botanists, however, continued to use Linnaeus’s sexual system almost exclusively for another two decades. Their reluctance to use other methods or systems of classification can be attributed to a culture suspicious of innovation, anti-French sentiment and the association of all things Linnaean with English national pride, fostered in particular by the President of the Linnean Society of London, Sir James Edward Smith. The British aversion to using multiple plant identification technologies in one text also helps explain why it took so long for English botanists to adopt the natural method, even after several Englishmen had tried to introduce it to their country. Historians of ornithology emphasize that the popularity of ornithological guides in the 19th and 20th centuries stems from their illustrations, illustrations made possible by printing technologies that improved illustration quality and reduced costs. Though illustrations are the most obvious features of late 19th century and 20th century guides, the organizational principles that make them functional as identification devices come from techniques developed in botanical works in the 18th century.     

包埋玻璃化法超低温保存植物种质的研究进展

包埋玻璃化法是在玻璃化法和包埋脱水法基础上发展起来的超低温保存植物种质的新技术。它具有能同时处理大量材料,处理后恢复生长快,对材料的毒害作用较小及成芽率高等优点,已成功地用于辣根、山嵛菜等20余种植物,在植物种质资源的保存上显示出了巨大的应用潜力。本文介绍了包埋玻璃化法产生的背景及其优点, 阐述了包埋玻璃化法的基本方法和预培养、包埋、脱水、化冻及恢复培养等过程,比较了该法冻存后的效果和冻存后所形成植株的遗传稳定性,同时指出了进一步研究的重点。