海绵共附生微生物的研究新进展

海绵是最原始的一类后生动物,已被作为海洋活性化合物的重要来源之一,其独特的孔状结构使其成为许多海洋微生物的优良宿主。近年来国内对海绵及其共附生微生物的研究主要集中在它们产生的活性物质方面,但对海绵共附生微生物的分布、多样性及其对宿主海绵作用的研究鲜有报道,就国内外研究进展进行了综述。     

Drugs from the seas - current status and microbiological implications

The oceans are the source of a large group of structurally unique natural products that are mainly accumulated in invertebrates such as sponges, tunicates, bryozoans, and molluscs. Several of these compounds (especially the tunicate metabolite ET-743) show pronounced pharmacological activities and are interesting candidates for new drugs primarily in the area of cancer treatment. Other compounds are currently being developed as an analgesic (ziconotide from the mollusc Conus magus) or to treat inflammation. Numerous natural products from marine invertebrates show striking structural similarities to known metabolites of microbial origin, suggesting that microorganisms (bacteria, microalgae) are at least involved in their biosynthesis or are in fact the true sources of these respective metabolites. This assumption is corroborated by several studies on natural products from sponges that proved these compounds to be localized in symbiotic bacteria or cyanobacteria. Recently, molecular methods have successfully been applied to study the microbial diversity in marine sponges and to gain evidence for an involvement of bacteria in the biosynthesis of the bryostatins in the bryozoan Bugula neritina.     

化学生态学在海洋污损生物防除中的应用

在海洋环境中,许多海洋生物都能产生对环境无危害的、具有防污活性的次生代谢产物以保护自身的洁净,利于自身的生存.用化学生态学的方法从海洋生物中提取天然防除物质成为近年来解决海洋污损生物问题的新思路,其目标是寻找高效无毒的防污材料取代原有的对海洋环境有严重危害的化学合成防污材料.虽然目前对提取生物的次生代谢产物的防污机理还所知甚少,但不少从海洋生物中获得的天然产物已显示出良好的防污活性.要解决污损生物防污问题,还需对天然产物的作用机制、生态学效应、天然产物与涂料的结合、控制和释放及野外实验进行更加深入的研究与探讨.     

Occurrence, fate, and biodegradation of estrogens in sewage and manure

The estrogens estrone (E1), 17α-estradiol (E2α), 17β-estradiol (E2β), and estriol (E3) are natural sex hormones produced by humans and animals. In addition, there are some synthetic estrogens, such as 17α-ethinylestradiol (EE2), used for contraception purposes. These compounds are able to produce endocrine disruption in living organisms at nanogram-per-liter levels. In both humans and animals, estrogens are excreted in urine and feces, reaching the natural environment through discharge from sewage treatment plants (STP) and manure disposal units. In STPs, hormone removal depends on the type of treatment process and on different parameters such as the hydraulic and sludge retention times. Thus, hormone elimination rates vary from 0% to 90% in different STPs. Animals are also an important source of estrogens in the environment. Indeed, animals produce high concentrations of hormones which will end up in manure which is typically spread on land. Hence, waste-borne animal hormones may transfer these pollutants to the soil. The purpose of this review is to highlight the significance for both health and the environment of pollution by estrogens and critically review the existing knowledge on their fate and removal in different treatment processes. Relevant information on the microbial degradation of hormones and metabolic pathways is also included.     

Application of LC/MS systems to structural characterization of flavonoid glycoconjugates

Mass spectrometry is currently one of the most versatile and sensitive instrumental methods applied to structural characterization of plant secondary metabolite mixtures isolated from biological material. Plant tissues contain thousands of natural products fulfilling different roles in plant physiology and biochemistry. These natural products have various biological activities in respect to plants synthesizing them, in their responses to different environmental stresses and are also active principles of food supplements and pharmaceuticals of plant origin. Flavonoids constitute a large group of phenolic secondary metabolites and are probably produced by all terrestrial plant species. More than 9000 glycoconjugates of flavonoids are presently known in the plant kingdom and more than 50 of them may be present in a single plant. For this reason methods of identification and analysis of this group of compounds are particularly demanded. Due to a high number of metabolites present in plant extracts, the isolation and purification of most compounds in amounts suitable for unambiguous characterization with NMR methods is often impossible. For these reasons elaboration of strategies for sufficiently precise structural characterization of compounds present in mixture samples is currently a primary task. Mass spectrometry, thanks to application of different physical phenomena for ionization, separation and detection of analyzed molecules, became the method of choice among analytical methods applied for identification, structural characterization and quantitative analysis of the natural products. Methods of analysis of differently substituted flavonoids (O- and C-glycosides, differentiation of various oligosaccharidic substituents, detection of acylated compounds) are presented in the paper. A proper application of mass spectrometric methods in well-defined and strictly controlled technical parameters of analysis permits obtaining important structural information. Among others, recording collision induced dissociation mass spectra allows identification of compounds after comparison of the registered MS spectra with these present in the existing databases.     

Diversity and biotechnological potential of the sponge-associated microbial consortia

Sponges are well known to harbor diverse microbes and represent a significant source of bioactive natural compounds derived from the marine environment. Recent studies of the microbial communities of marine sponges have uncovered previously undescribed species and an array of new chemical compounds. In contrast to natural compounds, studies on enzymes with biotechnological potential from microbes associated with sponges are rare although enzymes with novel activities that have potential medical and biotechnological applications have been identified from sponges and microbes associated with sponges. Both bacteria and fungi have been isolated from a wide range of marine sponge, but the diversity and symbiotic relationship of bacteria has been studied to a greater extent than that of fungi isolated from sponges. Molecular methods (e.g., rDNA, DGGE, and FISH) have revealed a great diversity of the unculturable bacteria and archaea. Metagenomic approaches have identified interesting metabolic pathways responsible for the production of natural compounds and may provide a new avenue to explore the microbial diversity and biotechnological potential of marine sponges. In addition, other eukaryotic organisms such as diatoms and unicellular algae from marine sponges are also being described using these molecular techniques. Many natural compounds derived from sponges are suspected to be of bacterial origin, but only a few studies have provided convincing evidence for symbiotic producers in sponges. Microbes in sponges exist in different associations with sponges including the true symbiosis. Fungi derived from marine sponges represent the single most prolific source of diverse bioactive marine fungal compounds found to date. There is a developing interest in determining the true diversity of fungi present in marine sponges and the nature of the association. Molecular methods will allow scientists to more accurately identify fungal species and determine actual diversity of sponge-associated fungi. This is especially important as greater cooperation between bacteriologists, mycologists, natural product chemists, and bioengineers is needed to provide a well-coordinated effort in studying the diversity, ecology, physiology, and association between bacteria, fungi, and other organisms present in marine sponges.     

Bioactive peptides from marine organisms: a short overview

Marine organisms are an immense source of new biologically active compounds. These compounds are unique because the aqueous environment requires a high demand of specific and potent bioactive molecules. Diverse peptides with a wide range of biological activities have been discovered, including antimicrobial, antitumoral, and antiviral activities and toxins amongst others. These proteins have been isolated from different phyla such as Porifera, Cnidaria, Nemertina, Crustacea, Mollusca, Echinodermata and Craniata. Purification techniques used to isolate these peptides include classical chromatographic methods such as gel filtration, ionic exchange and reverse-phase HPLC. Multiple in vivo and in vitro bioassays are coupled to the purification process to search for the biological activity of interest. The growing interest to study marine natural products results from the discovery of novel pharmacological tools including potent anticancer drugs now in clinical trials. This review presents examples of interesting peptides obtained from different marine organisms that have medical relevance. It also presents some of the common methods used to isolate and characterize them.     

城市植物源挥发性有机化合物排放特征及其大气环境效应研究进展

在外界环境的刺激下,植物会通过释放挥发性有机化合物来维护自身生长。城市是人类活动的主要集聚地,剧烈的人为干扰导致城市环境特征呈现出复杂的变化趋势,从而使城市植物排放挥发性有机化合物的过程与自然界出现较大差异。城市中的植物源挥发性有机化合物(Biogenic Volatile Organic Compounds, BVOCs)会直接与城市中的氧化物质接触,生成二次污染物,并在高温、强光照的条件下发生光化学反应,严重破坏城市大气环境,危害居民健康。总结了城市BVOCs的常见类型、作用机制及现有研究方法,分析了不同时间、空间和人类活动背景下的城市BVOCs排放特征,并进一步梳理了当前研究的不足,提出未来重点研究方向,旨在为大气环境治理、环境空间规划、居民健康保障等方面的城市管理工作提供指导。     

Biological and enzymatic treatment of bisphenol A and other endocrine disrupting compounds: a review

Bisphenol A is predominantly used as an intermediate in the production of polycarbonate plastics and epoxy resins. Traces of bisphenol A released into the environment can reach into the wastewater and soil via application of sewage sludge from wastewater treatment systems that receive water containing bisphenol A, or from leachate from uncontrolled landfills. In this study we have made an effort to review the work on the presence of bisphenol A and other related endocrine disrupting compounds in the environment and their impact on the life of living organisms including human beings. Bisphenol A has several implications on the health of human beings as well it can also affect the growth of plants and animals. Number of physicochemical methods such as adsorption, membrane based filtration, ozonation, fenton, electrochemical and photochemical degradation has been used for the removal of bisphenol A. However, these methods have some inherent limitations and therefore cannot be used for large scale treatment of such pollutants. The alternative procedures have attracted the attention of environmental scientists. Biological methods are looking quite promising and these procedures are helpful in the complete degradation of bisphenol A and related compounds. Several bacterial, fungal, and algal strains and mixed cultures have successfully been employed for the degradation of bisphenol A. Recently, enzymatic methods have attracted the attention of the environmentalists for the treatment of bisphenol A and other endocrine disrupting compounds. Numerous types of oxidoreductases; laccases, tyrosinases, manganese peroxidase, lignin peroxidase, polyphenol oxidases, horseradish peroxidase and bitter gourd peroxidase have exhibited their potential for the remediation of such types of compounds. The cytochrome P 450 monooxygenases and hemoglobin have also participated in the degradation of bisphenol A and other related endocrine disrupting compounds. Various redox mediators, surfactants and additives have also enhanced enzymatic oxidation of bisphenol A and other related endocrine disrupting compounds.     

Domestic Water Use in the United States: A Life-Cycle Approach

Water and energy are two primary natural resources used by building occupants. A life-cycle assessment (LCA) is performed for water-consuming plumbing fixtures and water-consuming appliances during their operational life for four different building types. Within the cycle studied, water is extracted from the natural environment, subjected to water treatment, pumped to buildings for use, collected for wastewater treatment, and discharged back to the natural environment. Specifically, the impacts of water use, electricity and natural gas generation, energy consumption (for water and wastewater treatment, and for water heating), and the manufacture of water and wastewater treatment chemicals are evaluated both quantitatively and qualitatively on a generalized national level in the United States of America.
It is concluded that water use and consumption within buildings have a much larger impact on resource consumption than the water and wastewater treatment stages of the life cycle. To study this more specifically, the resource consumption of four different building types-an apartment building, a college dormitory, a motel, and an office building-is considered. Of these four building types, the apartment has the highest energy consumption (for water and wastewater treatment, and for water heating) per volume of water used, whereas the office building has the lowest. Similarly, the calculated LCA score for the apartment building is typically greater than those of the other three building types.     

Studies of RyR function in situ

The ryanodine receptors (RyRs) are intracellular Ca2+ release channels of the sarcoplasmic reticulum (SR) involved in many cellular responses, including muscle excitation-contraction coupling. Multiple biochemical and biophysical methods are available to study RyR functions. However, most of them are somewhat limited because they can only be used to examine channels which are purified from the SR and no longer in their natural environment. In this review we discuss optical methods for studying RyR functions in situ. We describe several techniques for the investigation of local (microscopic) intracellular Ca2+ signals (a.k.a Ca2+ sparks) by means of confocal microscopy and flash photolysis of caged compounds. We discuss how these studies can and will continue to contribute to our understanding of RyR function in physiological and pathological conditions.     

Isolation and characterization of antimicrobial food components

Nowadays there is an evident growing interest in natural antimicrobial compounds isolated from food matrices. According to the type of matrix, different isolation and purification steps are needed and as these active compounds belong to different chemical classes, also different chromatographic and electrophoretic methods coupled with various detectors (the most used diode array detector and mass spectrometer) have to be performed. This review covers recent steps made in the fundamental understanding of sample preparation methods as well as of analytical tools useful for the complete characterization of bioactive food compounds. The most commonly used methods for extraction of natural antimicrobial compounds are the conventional liquid-liquid or solid-liquid extraction and the modern techniques such as pressurized liquid extraction, microwave-assisted extraction, ultrasound-assisted extraction, solid-phase micro-extraction, supercritical fluid extraction, and matrix solid phase dispersion. The complete characterization of the compounds is achieved using both monodimensional chromatographic processes (LC, nano-LC, GC, and CE coupled with different type of detectors) and, recently, using comprehensive two-dimensional systems (LC×LC and GC×GC).     

Extraction and analysis of polyphenols: recent trends

In recent years, there has been an increasing interest in diets rich in fruits and vegetables and this is mostly due to their presumed role in the prevention of various degenerative diseases, such as cancer and cardiovascular diseases. This is mainly due to the presence of bioactive compounds, such as polyphenols, carotenoids, among others. Polyphenols are one of the main classes of secondary metabolites derived from plants offering several health benefits resulting in their use as functional foods. Prior to the use of these polyphenols in specific applications, such as food, pharmaceutical, and the cosmetic industries, they need to be extracted from the natural matrices, then analyzed and characterized. The development of an efficient procedure for the extraction, proper analysis, and characterization of phenolic compounds from different sources is a challenging task due to the structural diversity of phenolic compounds, a complex matrix, and their interaction with other cellular components. In this light, this review discusses different methods of extraction, analysis, and the structural characterization of polyphenolic compounds.     

Features and applications of bacterial glycosyltransferases: current state and prospects

The bioactivity of many natural products including valuable antibiotics and anticancer therapeutics depends on their sugar moieties. Changes in the structures of these sugars can deeply influence the biological activity, specificity and pharmacological properties of the parent compounds. The chemical synthesis of such sugar ligands is exceedingly difficult to carry out and therefore impractical to establish on a large scale. Therefore, glycosyltransferases are essential tools for chemoenzymatic and in vivo approaches for the development of complex glycosylated natural products. In the last 10 years, several examples of successful alteration and diversification of natural product glycosylation patterns via metabolic pathway engineering and enzymatic glycodiversification have been described. Due to the relaxed substrate specificity of many sugar biosynthetic enzymes and glycosyltransferases involved in natural product biosynthesis, it is possible to obtain novel glycosylated compounds using different methods. In this review, we would like to provide an overview of recent advances in diversification of the glycosylated natural products and glycosyltransferase engineering.     

Disaccharide Nucleosides and Oligonucleotides on Their Basis. New Tools for the Study of Enzymes of Nucleic Acid Metabolism

The main structural features of an important group of natural compounds, disaccharide nucleosides, are reviewed. The synthesis and properties of modified oligonucleotides on their basis as well as the methods of introduction of reactive aldehyde groups are described. The last part is devoted to the application of these compounds for studies of enzymes of nucleic acid metabolism.     

Degradation of chlorinated nitroaromatic compounds

Chlorinated nitroaromatic compounds (CNAs) are persistent environmental pollutants that have been introduced into the environment due to the anthropogenic activities. Bacteria that utilize CNAs as the sole sources of carbon and energy have been isolated from different contaminated and non-contaminated sites. Microbial metabolism of CNAs has been studied, and several metabolic pathways for degradation of CNAs have been proposed. Detoxification and biotransformation of CNAs have also been studied in various fungi, actinomycetes and bacteria. Several physicochemical methods have been used for treatment of wastewater containing CNAs; however, these methods are not suitable for in situ bioremediation. This review describes the current scenario of the degradation of CNAs.     

Synthetic approaches to polycyclic semiochemicals and their derivatives: combinatorial methods towards phytochemicals

Semiochemicals are natural products occurring in plants, bacteria or animals which function as carriers of a special message. Depending on the mode of function of the semiochemicals, they are divided into pheromones that trigger a response in members of the same species and allelochemicals (kairomones, allomones) that act between individuals of different species. Semiochemicals are very important compounds that influence the behavior of plants and animals and their adaption to a changing environment. As their importance for plants, animals and the ecological system itself is huge, the synthetic access to these chemicals, their precursors and derivatives is of high interest. Beyond novel strategies for the construction of semiochemical skeletons, combinatorial methods have been implemented to synthesize medium-sized and large-sized libraries that enable diverse modifications of the active compounds. These combinatorial approaches allow the screening for more active compounds and they elucidate the mode of action of the semiochemical or of the biological target. This review summarizes the state of the art procedures for the synthesis of important skeletons appearing in semiochemicals and gives special synthetic procedures for selected examples if the procedure is suitable for a general transfer to the synthesis of derivatives. The synthetic examples are given in the context of known active phytochemicals and their function that allows an evaluation of the given procedures with respect to the fulfillment of the common structural requirements (the structural diversity and flexibility) and the importance for the regulation of biological systems. Parts of this review were given in a lecture at the BioCom 12 in Cadiz, 2012.     

Diversity and biogeography of marine actinobacteria

The actinomycetes, although not all the Actinobacteria, are easy to isolate from the marine environment. However, their ecological role in the marine ecosystem is largely neglected and various assumptions meant there was little incentive to isolate strains for search and discovery of new drugs. However, the marine environment has become a prime resource in search and discovery for novel natural products and biological diversity, and marine actinomycetes turn out to be important contributors. Similarly, striking advances have been made in marine microbial ecology using molecular techniques and metagenomics, and actinobacteria emerge as an often significant, sometimes even dominant, environmental clade. Both approaches - cultivation methods and molecular techniques - are leading to new insights into marine actinobacterial biodiversity and biogeography. Very different views of actinobacterial diversity emerge from these, however, and the true extent and biogeography of this are still not clear. These are important for developing natural product search and discovery strategies, and biogeography is a hot topic for microbial ecologists.     

Comparative X-ray and Fourier-transform-infrared investigations of conformational properties of bacterial and synthetic lipid A of Escherichia coli and Salmonella minnesota as well as partial structures and analogues thereof

By using the X-ray and infrared spectroscopic characteristics of various synthetic analogues and partial structures of lipid A in the dried state, a comparison of these compounds with their natural counterparts was undertaken. As judged by their X-ray diffraction and infrared spectroscopic features, the compounds tested could be divided into two main groups. The first group covered those samples synthesized in accordance with a previously assumed structure, while those synthesized in accordance with present knowledge on the lipid-A primary structure formed the second group. Members of the first group were characterized by a liquid-like, alpha-type arrangement of their fatty acyl chains in a non-lamellar supramolecular structure, while all members of the second group formed bilayered phases with a much more ordered, beta-type conformation of their fatty acyl chains. Synthetic Escherichia coli-type lipid A (compound 506), proved to be essentially identical to its natural counterpart with respect to those conformational properties accessible by our methods. The synthetic hepta-acyl species of Salmonella minnesota lipid A (compound 516) revealed an unexpected conformational behaviour, whereby a fatty-acyl-chain packing could be detected which was different from the hexagonal arrangement found for all other compounds of the second group.     

Isolation and extraction of some compounds that act as antimicrobials from actinomycetes

Some types of actinomycetes produce many different secondary metabolites of fatty acids, hydrocarbons, or other compounds. Many of these products play an important role in various medical fields. This study aims to extract natural compounds from actinomycetes after their isolation from the soil and their identification as antimicrobials. Soil samples were collected from different regions after being treated by known methods. Colonies that indicate actinomycetes were replanted and provided with suitable conditions for growth, and then tested against a number of pathogenic microbes. Isolate 3-D is more effective than others. D-3 was exposed to ultraviolet rays for greater production of antimicrobials. The compounds obtained from the isolates were extracted by the column chromatography technique. To identify the compounds resulting from the extract, the Gas Chromatography-Mass Spectrometry (GC–MS) technique was used. Ten compounds have been identified by GC–MS. Some of the compounds are of fatty acid nature, and some are hydrocarbons. These compound includes Hexadecane, 2,6,11,15- Tetramethyl – Octacosane - Dodecanoic Acid, 1,2,3- Propane-triyl ester – Hexatriacontane – Heptacosane - Eicosyl Acetate – Tritetracontane - Tetracosane, 2,6,10,15,19,23-Hexamethyl - Myristic Acid vinyl ester – Tetratetracontane. All of these extracts are of medical importance. Some of them are anti-bacterial, some are anti-allergic, anti-inflammatory, anti-cancer, anti-fungal, antioxidants, and some of them are essential ingredients in cosmetics. The current study showed that isolated D-3 actinomycetes from soil have the ability to produce antimicrobials against a variety of gram-negative and gram-positive bacteria, which are important in the medical field.