水生植物轮藻特殊气味的分析研究

本实验采用热脱附气质联用技术(TCT-GC/MS)对山西省内三种轮藻的挥发性气味的化学成分(VOCs)进行了分析,共鉴定出43种物质,主要为烷烃类、酮类、醇类等物质,其中野生不连续轮藻、实验室培养的不连续轮藻和普生轮藻的挥发性物质组成基本相似,以烷烃类为主,而钝节拟丽藻的气味组成与它们存在较大差异,说明其存在属间差异;在轮藻的VOCs组成中,发现了苯并噻唑、青叶醛、α-蒎烯和为薄荷烯等有记载的对昆虫起趋避和杀灭作用的化合物,所以轮藻应具有杀虫活性;另外还在其VOCs组成中发现了苯系物的存在,说明轮藻对其有吸附作用,但这种吸附作用同样存在属间差异。     

Including the use phase in LCA of floor coverings

The results from two previously published case studies were used to assess the importance of use-related emissions from building materials in a life cycle perspective. The first study was an LCA study of linoleum, vinyl flooring, and solid wood flooring, while the second study examined the Volatile Organic Compounds (VOCs) emitted by these floorings. For linoleum and vinyl flooring, the emitted amounts for the use phase are of much the same magnitude as those emitted in the rest of the life cycle, but in the case of solid wood flooring the emissions of the use phase far exceed those of the remaining life cycle. The ranking of the selected floorings in the LCA study did not change when the impact of the use phase was also considered. This study recommends that LCAs should not neglect flooring-related emissions in the use phase when assessing regional and global environmental effects.     

Kinetic analysis of high-concentration isopropanol biodegradation by a solvent-tolerant mixed microbial culture

The ability of a previously enriched microbial population to utilize isopropanol (IPA) as the sole carbon source within a minimal salts medium is studied. The advantage of prior enrichment procedures for the improvement of IPA biodegradation performance is demonstrated for an IPA concentration of up to 24 g L(-1). Results showing the interrelationship between temperature and substrate utilization and inhibition levels at temperatures of between 2 degrees C and 45 degrees C are examined. Models of inhibition based on enzyme kinetics are assessed via nonlinear analysis, in order to accurately represent the growth kinetics of this solvent-tolerant mixed culture. The model that best describes the data is the Levenspiel substrate inhibition model, which can predict the maximum substrate level above which growth is completely limited. This is the first report of IPA treatment of up to 24 g L(-1) by an aerobic solvent-tolerant population.     

Truffle volatiles inhibit growth and induce an oxidative burst in Arabidopsis thaliana

The function of fungal volatiles in fungal-plant interactions is poorly understood. The aim here was to address this lack of knowledge, focusing on truffles, ectomycorrhizal fungi that are highly appreciated for their aroma. The effect of volatiles released by truffles was tested on Arabidopsis thaliana in a closed chamber bioassay. The volatiles produced by Tuber melanosporum, Tuber indicum and Tuber borchii fruiting bodies inhibited A. thaliana in terms of root length and cotyledon leaf size, and in some cases induced a bleaching of the seedlings, thus indicating toxicity. Ten synthetic volatiles were tested in a similar way. The strongest inhibitory effect was observed with C(8) molecules such as 1-octen-3-ol, an alcohol with a typical 'fungal smell'. Two of these C(8) compounds were further tested to investigate their mechanism of action. 1-Octen-3-ol and trans-2-octenal induced an oxidative burst (hydrogen peroxide, H(2)O(2)) in the A. thaliana leaves as well as a strong increase in the activities of three reactive oxygen species (ROS)-scavenging enzymes. These results demonstrate that fungal volatiles inhibit the development of A. thaliana and modify its oxidative metabolism. Even though limited to laboratory observations, these results indicate the presence of a hitherto unknown function of fungal volatiles as molecules that mediate fungal-plant interactions.     

Transient performance of two-phase partitioning bioreactors treating a toluene contaminated gas stream

Two-phase partitioning bioreactors (TPPBs) consist of a cell-containing aqueous phase and an immiscible organic phase that sequesters and delivers toxic substrates to cells based on equilibrium partitioning. The immiscible organic phase, which acts as a buffer for inhibitory substrate loadings, makes it possible for TPPBs to handle high volatile organic compound (VOC) loadings, and in this study the performance of liquid n-hexadecane and solid styrene butadiene (SB) polymer beads used as partitioning phases were compared to a single aqueous phase system while treating transient loadings of a toluene contaminated air stream by Achromobacter xylosoxidans Y234. The TPPBs operated as well-mixed stirred tanks, with total working volumes of 3 L (3 L aqueous for the single-phase system, 2 L aqueous and 1 L n-hexadecane for the solvent system, and 2.518 L aqueous volume and 500 g of SB beads for the polymer system). Two 60-min step changes (7 and 17 times the nominal loading rates, termed "small" and "large" steps, respectively) were imposed on the systems and the performance was characterized by the overall removal efficiencies, instantaneous removal efficiency recovery times (above 95% removal), and dissolved oxygen recovery times. For the small steps, with a nominal loading of 343 g/m3/h increasing to 2,400 g/m3/h, the TPPB system using n-hexadecane as the second phase performed best, removing 97% of the toluene fed to the system compared with 90% for the polymer beads system and only 69% for the single-phase system. The imposed large transient gave similar results, although the impact of the presence of a second sequestering phase was more pronounced, with the n-hexadecane system maintaining much reduced aqueous toluene concentrations leading to significantly improved performance. This investigation also showed that the presence of both n-hexadecane and SB beads improved the oxygen transfer within the systems.     

Effects of discrete bioactive microbial volatiles on plants and fungi

Plants live in association with microorganisms, which are well known as a rich source of specialized metabolites, including volatile compounds. The increasing numbers of described plant microbiomes allowed manifold phylogenetic tree deductions, but less emphasis is presently put on the metabolic capacities of plant‐associated microorganisms. With the focus on small volatile metabolites we summarize (i) the knowledge of prominent bacteria of plant microbiomes; (ii) present the state‐of‐the‐art of individual (discrete) microbial organic and inorganic volatiles affecting plants and fungi; and (iii) emphasize the high potential of microbial volatiles in mediating microbe–plant interactions. So far, 94 discrete organic and five inorganic compounds were investigated, most of them trigger alterations of the growth, physiology and defence responses in plants and fungi but little is known about the specific molecular and cellular targets. Large overlaps in emission profiles of the emitters and receivers render specific volatile organic compound‐mediated interactions highly unlikely for most bioactive mVOCs identified so far.     

微生物源挥发性物质防治采后果蔬病害的研究进展

随着化学杀菌剂弊端的日益凸显,生物防治已逐渐成为采后果蔬病害控制的研究和开发热点.其中,很多微生物产生的多种挥发性物质(volatile organic compounds,VOCs),能显著抑制多种病原菌的生长繁殖,有效控制采后果蔬病害.由于微生物源VOCs具有有效、安全、环保、易降解和无残留等优点,越来越受到各国研...     

Antibody escape and cryptic cross-domain stabilization in the SARS-CoV-2 Omicron spike protein

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Floral Phytochemistry: Impact of Volatile Organic Compounds and Nectar Secondary Metabolites on Pollinator Behavior and Health

Plants produce a plethora of phytochemicals including sugars, amino acids (AAs), volatile organic compounds (VOCs) and secondary metabolites (SMs) with different ecological functions. To attract pollinators and defenders and ensure reproductive success, plants mainly rely on VOCs, while to reward insects, plants synthesize nectar rich in sugars and AAs. Furthermore, plant SMs can play various roles. Some components are able to interact with the nervous system of insects by binding to neuron receptor proteins and thus manipulate pollinator behavior. Others, like alkaloids and phenolics, protect from nectar robbers and enhance memory and foraging efficiency, or, as in the case of flavonoids, exhibit high antioxidant activities supporting pollinator well-being. This review discusses the impact of VOCs and nectar SMs on insect behavior and pollinator health.