Advances in abscisic acid biosynthesis / 生物工程学报

Abscisic acid, a plant hormone that inhibits growth, is a key factor in balancing plant endogenous hormones and regulating growth and metabolism. Abscisic acid can improve the drought resistance and salt tolerance of crops, reduce fruit browning, reduce the incidence rate of malaria and stimulate insulin secretion, so it has a broad application potential in agriculture and medicine. Compared with traditional plant extraction and chemical synthesis, abscisic acid synthesis by microorganisms is an economic and sustainable route. At present, a lot of progress has been made in the synthesis of abscisic acid by natural microorganisms such as Botrytis cinerea and Cercospora rosea, while the research on the synthesis of abscisic acid by engineered microorganisms is rarely reported. Saccharomyces cerevisiae, Yarrowia lipolytica and Escherichia coli are common hosts for heterologous synthesis of natural products due to their advantages of clear genetic background, easy operation and friendliness for industrial production. Therefore, the heterologous synthesis of abscisic acid by microorganisms is a more promising production method. The author reviews the research on the heterologous synthesis of abscisic acid by microorganisms from five aspects: selection of chassis cells, screening and expression enhancement of key enzymes, regulation of cofactors, enhancement of precursor supply and promotion of abscisic acid efflux. Finally, the future development direction of this field is prospected.

Phenylpropanoid pathway in plants and its role in response to heavy metal stress: a review / 生物工程学报

Phenylpropanoid metabolic pathway is one of the most important secondary metabolic pathways in plants. It directly or indirectly plays an antioxidant role in plant resistance to heavy metal stress, and can improve the absorption and stress tolerance of plants to heavy metal ions. In this paper, the core reactions and key enzymes of the phenylpropanoid metabolic pathway were summarized, and the biosynthetic processes of key metabolites such as lignin, flavonoids and proanthocyanidins and relevant mechanisms were analyzed. Based on this, the mechanisms of key products of phenylpropanoid metabolic pathway in response to heavy metal stress were discussed. The perspectives on the involvement of phenylpropanoid metabolism in plant defense against heavy metal stress provides a theoretical basis for improving the phytoremediation efficiency of heavy metal polluted environment.

In vitro antibacterial-antibiofilm effect of Hypericum atomarium Boiss and chemical composition

Abstract Treatment with plant is considered an effective option against increased antibiotic resistance. In this study antibiofilm activity of methanol (CH3OH), chloroform (CHCl3), ethyl acetate (EtOAc) and water (H2O) extracts of Hypericum atomarium Boiss. which is member of Hypericum genus was evaluated in Pseudomonas aeruginosa PAO1 and antibacterial performance against Gram (+) and Gram (-) strains and also bioactive compounds of extract were analysed using by HPLC and GC-MS. According to antibacterial activity test results the extracts were effective all Gram (+) bacteria and Gram (-) Chromobacterium violaceum (MICs ranging from 0.42 µg/ml to 4.3 mg). Inhibition effect of biofilm formation was found to be different rate in extracts (methanol-63%, chloroform-52%). The major flavonoids were detected (−)-epicatechin (2388.93 µg/ml) and (+)-catechin (788.94 µg/ml). The main phenolic acids were appeared as caffeic acid 277.34 µg/ml and chlorogenic acid 261.79 µg/ml. And according to GC results α-pinene was found main compound for three solvent extracts methanol, chloroform and ethyl acetate 67.05, 62.69, 49.28% rate respectively

In vivo antimalarial activity of self-nanoemulsifying drug delivery systems containing ethanolic extract of Morinda lucida in combination with other Congolese plants extracts

Abstract Morinda lucida leaves are largely used by Congolese traditional healers for the treatment of uncomplicated malaria. The antimalarial activity of their ethanolic extract has been confirmed both in vitro and in vivo. However, the development of relevant formulations for potential clinical application is hampered since the active ingredients contained in this extract exhibit poor water solubility and low oral bioavailability. Hence, this work aims not only to develop self-nanoemulsifying drug delivery systems (SNEDDSs) for oral delivery of the ethanolic extract of Morinda lucida (ML) but also to evaluate its oral antimalarial activity alone and in combination with other Congolese ethanolic plant extracts (Alstonia congensis, Garcinia kola, Lantana camara, Morinda morindoides or Newbouldia laevis). Based on the solubility of these different extracts in various excipients, SNEDDS preconcentrates were prepared, and 200 mg/g of each plant extract were suspended in these formulations. The 4-day suppressive Peter's test revealed a significant parasite growth inhibiting effect for all the extract-based SNEDDS (from 55.0 to 82.4 %) at 200 mg/kg. These activities were higher than those of their corresponding ethanolic suspensions given orally at the same dose (p<0.05). The combination therapy of MLSNEDDS with other extract-based SNEDDS exhibited remarkable chemosuppression, ranging from 74.3 % to 95.8 % (for 100 + 100 mg/kg) and 86.7 % to 95.5 % (for 200 + 200 mg/kg/day). In regard to these findings, SNEDDS suspension may constitute a promising approach for oral delivery of ML alone or in combination with other antimalarial plants.

Identification and expression analysis of WRKY gene family in eukaryotic algae / 生物工程学报

WRKY is a superfamily of plant-specific transcription factors, playing a critical regulatory role in multiple biological processes such as plant growth and development, metabolism, and responses to biotic and abiotic stresses. Although WRKY genes have been characterized in a variety of higher plants, little is known about them in eukaryotic algae, which are close to higher plants in evolution. To fully characterize algal WRKY family members, we carried out multiple sequence alignment, phylogenetic analysis, and conserved domain prediction to identify the WRKY genes in the genomes of 30 algal species. A total of 24 WRKY members were identified in Chlorophyta, whereas no WRKY member was detected in Rhodophyta, Glaucophyta, or Bacillariophyta. The 24 WRKY members were classified into Ⅰ, Ⅱa, Ⅱb and R groups, with a conserved heptapeptide domain WRKYGQ(E/A/H/N)K and a zinc finger motif C-X4-5-C-X22-23-H-X-H. Haematococcus pluvialis, a high producer of natural astaxanthin, contained two WRKY members (HaeWRKY-1 and HaeWRKY-2). Furthermore, the coding sequences of HaeWRKY-1 and HaeWRKY-2 genes were cloned and then inserted into prokaryotic expression vector. The recombinant vectors were induced to express in Escherichia coli BL21(DE3) cells and the fusion proteins were purified by Ni-NTA affinity chromatography. HaeWRKY-1 had significantly higher expression level than HaeWRKY-2 in H. pluvialis cultured under normal conditions. High light stress significantly up-regulated the expression of HaeWRKY-1 while down-regulated that of HaeWRKY-2. The promoters of HaeWRKY genes contained multiple cis-elements responsive to light, ethylene, ABA, and stresses. Particularly, the promoter of HaeWRKY-2 contained no W-box specific for WRKY binding. However, the W-box was detected in the promoters of HaeWRKY-1 and the key enzyme genes HaeBKT (β-carotene ketolase) and HaePSY (phytoene synthase) responsible for astaxanthin biosynthesis. Considering these findings and the research progress in the related fields, we hypothesized that the low expression of HaeWRKY-2 under high light stress may lead to the up-regulation of HaeWRKY-1 expression. HaeWRKY-1 may then up-regulate the expression of the key genes (HaeBKT, HaePSY, etc.) for astaxanthin biosynthesis, consequently promoting astaxanthin enrichment in algal cells. The findings provide new insights into further analysis of the regulatory mechanism of astaxanthin biosynthesis and high light stress response of H. pluvialis.

Progress in circular RNAs of plants / 生物工程学报

With the development of high-throughput sequencing technology, circular RNAs (circRNAs) have gradually become a hotspot in the research on non-coding RNA. CircRNAs are produced by the covalent circularization of a downstream 3' splice donor and an upstream 5' splice acceptor through backsplicing, and they are pervasive in eukaryotic cells. CircRNAs used to be considered byproducts of false splicing, whereas an explosion of related studies in recent years has disproved this misconception. Compared with the rich studies of circRNAs in animals, the study of circRNAs in plants is still in its infancy. In this review, we introduced the discovery of plant circRNAs, the discovery of plant circRNAs, the circularization feature, expression specificity, conservation, and stability of plant circRNAs and expounded the identification tools, main types, and biogenesis mechanisms of circRNAs. Furthermore, we summarized the potential roles of plant circRNAs as microRNA (miRNA) sponges and translation templates and in response to biotic/abiotic stress, and briefed the degradation and localization of plant circRNAs. Finally, we discussed the challenges and proposed the future directions in the research on plant circRNAs.

Function, structure and catalytic mechanism of sucrose phosphate synthase: a review / 生物工程学报

Sucrose is a natural product occurs widely in nature. In living organisms such as plants, sucrose phosphate synthase (SPS) is the key rate-limiting enzyme for sucrose synthesis. SPS catalyzes the synthesis of sucrose-6-phosphate, which is further hydrolyzed by sucrose phosphatase to form sucrose. Researches on SPS in recent decades have been focused on the determination of enzymatic activity of SPS, the identification of the inhibitors and activators of SPS, the covalent modification of SPS, the carbohydrate distribution in plants regulated by SPS, the mechanism for promoting plant growth by SPS, the sweetness of fruit controlled by SPS, and many others. A systematic review of these aspects as well as the crystal structure and catalytic mechanism of SPS are presented.

Molecular mechanism of WRKY12 in regulating plant development / 生物工程学报

WRKY transcription factors are one of the largest families of transcription factors in higher plants and involved in regulating multiple and complex growth and development processes in plants. WRKY12 is a typical member of WRKY family. This article summarizes recent research progresses on the regulatory mechanism of WRKY12 in multiple growth and development processes, and analyzes the functional differences between WRKY12 and WRKY13. It provides a useful reference for further studying the molecular mechanism of WRKY12 in plant complex developments. It also provides clearer research ideas and reference strategies for exploring the self-regulation of other WRKY member and the mutual regulatory relationships between different WRKY family genes.

Stress and defense responses in plant secondary metabolites production

In the growth condition(s) of plants, numerous secondary metabolites (SMs) are produced by them to serve variety of cellular functions essential for physiological processes, and recent increasing evidences have implicated stress and defense response signaling in their production. The type and concentration(s) of secondary molecule(s) produced by a plant are determined by the species, genotype, physiology, developmental stage and environmental factors during growth. This suggests the physiological adaptive responses employed by various plant taxonomic groups in coping with the stress and defensive stimuli. The past recent decades had witnessed renewed interest to study abiotic factors that influence secondary metabolism during in vitro and in vivo growth of plants. Application of molecular biology tools and techniques are facilitating understanding the signaling processes and pathways involved in the SMs production at subcellular, cellular, organ and whole plant systems during in vivo and in vitro growth, with application in metabolic engineering of biosynthetic pathways intermediates.

Regulation of aquaporins in plants under stress

Abstract Aquaporins (AQP) are channel proteins belonging to the Major Intrinsic Protein (MIP) superfamily that play an important role in plant water relations. The main role of aquaporins in plants is transport of water and other small neutral molecules across cellular biological membranes. AQPs have remarkable features to provide an efficient and often, specific water flow and enable them to transport water into and out of the cells along the water potential gradient. Plant AQPs are classified into five main subfamilies including the plasma membrane intrinsic proteins (PIPs), tonoplast intrinsic proteins (TIPs), nodulin 26 like intrinsic proteins (NIPs), small basic intrinsic proteins (SIPs) and X intrinsic proteins (XIPs). AQPs are localized in the cell membranes and are found in all living cells. However, most of the AQPs that have been described in plants are localized to the tonoplast and plasma membranes. Regulation of AQP activity and gene expression, are also considered as a part of the adaptation mechanisms to stress conditions and rely on complex processes and signaling pathways as well as complex transcriptional, translational and posttranscriptional factors. Gating of AQPs through different mechanisms, such as phosphorylation, tetramerization, pH, cations, reactive oxygen species, phytohormones and other chemical agents, may play a key role in plant responses to environmental stresses by maintaining the uptake and movement of water in the plant body.

Caracterização bioquímica e funcional da proteína XadA3 de Xylella fastidiosa / Biochemistry and functional characterization of Xylella fastidiosa XadA3 adhesin

Gram-negativas e é utilizado por diversos patógenos para colonizar seus hospedeiros, sendo o primeiro passo do processo de desenvolvimento do biolfilme. Uma variedade de apêndices celulares e proteínas está envolvida na adesão bacteriana, tais como pili, fimbrias, adesinas fimbriais e afimbriais. O fitopatógeno Xylella fastidiosa, agente causal de importantes doenças como a doença de Pierce de videiras, a clorose variegada dos citros e a síndrome do rápido declínio de oliveiras, possui em sua superfície várias dessas estruturas que são potencialmente responsáveis pela colonização eficiente de insetos-vetores e plantas hospedeiras. Entre as adesinas afimbriais codificadas no genoma dessa bactéria, três XadA (XadA1, Hsf/XadA2 e XadA3) são classificadas como autotransportadores triméricos. Dados da literatura sugerem que XadA1 e XadA2 são importantes para a formação do biofilme, porém a função de XadA3 ainda não havia sido investigada. Nesse trabalho, tivemos como objetivo caracterizar bioquímica e funcionalmente a proteína XadA3 e obter informações adicionais sobre o papel desempenhado por XadA1 e XadA2 na adesão e virulência de X. fastidiosa. Utilizando imunodetecção com um anticorpo policlonal anti-XadA3 por nós obtido, demonstramos que essa proteína localiza-se na superfície bacteriana e medeia a adesão intercelular. A caracterização dos fenótipos de mutantes de deleção de cada um dos genes das adesinas XadA revelou que o mutante ΔxadA3 tem reduzida capacidade de agregação celular e formação de biofilme quando comparado tanto aos mutantes ΔxadA1 e ΔxadA2 como à cepa selvagem Temecula. A deleção dos genes xadA afeta marginalmente o perfil de expressão gênica global avaliado através de RNAseq das cepas mutantes comparativamente à cepa selvagem, porém destaca-se, nas cepas mutantes, o aumento nos níveis dos transcritos de lipases/esterases. Já foi descrito que essas enzimas parecem atuar na degradação do tecido vegetal associada aos sintomas da doença de Pierce de videiras. A deleção de xadA3 resulta em um fenótipo de hipervirulência em videiras, mas também de deficiência de transmissão pelo inseto-vetor. O conjunto dos resultados obtidos nesse trabalho evidenciam o importante papel desempenhado pelas adesinas XadAs, particularmente XadA3, na adesão intercelular, no desenvolvimento do biofilme e na virulência de X. fastidiosa

Adhesion is a widely conserved mechanism of virulence among Gram-negative bacteria that is used by several pathogens to colonize their hosts, being the first step in biolfilm development. A variety of appendages and proteins are involved in bacterial adhesion, such as pili, fimbriae, fimbrial and afimbrials adhesins. The phytopathogen Xylella fastidiosa, causal agent of important diseases such as Pierce's disease of grapevines, citrus variegated chlorosis and olive quick decline syndrome, harbours on its surface several of these structures that are potentially responsible for efficient colonization of insect vectors and plant hosts. Among the afimbrial adhesins encoded in the genome of this bacterium, three XadAs (XadA1, Hsf/XadA2 and XadA3) are classified as trimeric autotransporters. Data from the literature suggest that XadA1 and XadA2 are important for biofilm formation, but XadA3 function has not been yet investigated. In this work, we aimed to biochemically and functionally characterize the XadA3 protein and gather additional information about the role played by XadA1 and XadA2 in X. fastidiosa adhesion and virulence. Using immunodetection with a polyclonal anti-XadA3 antibody, we have demonstrated that this protein localizes to the bacterial surface and mediates intercellular adhesion. Phenotypic characterization of the deletion mutants of XadA adhesins encoded genes revealed that the ΔxadA3 mutant has reduced cell aggregation capacity and biofilm formation when compared to both ΔxadA1 and ΔxadA2 mutants as well as to Temecula wild type strain. Deletion of the xadA genes marginally affects the global gene expression profile assessed by RNA-seq of the mutant strains compared to the wild-type strain, eventhough an increase in lipase/esterase transcripts levels was observed in the mutant strains. It has been reported that these enzymes appear to participate in the degradation of plant tissue that is associated with symptoms of Pierce's disease of grapevines. The deletion of xadA3 results in a phenotype of hypervirulence in grapevines but also of deficiency in insect-vector transmission. The results obtained in this work evidenced the important role played by XadAs adhesins, particularly XadA3, in X. fastidiosa intercellular adhesion, biofilm development and virulence

Isolation of fungi from dung of wild herbivores for application in bioethanol production

ABSTRACT Producing biofuels such as ethanol from non-food plant material has the potential to meet transportation fuel requirements in many African countries without impacting directly on food security. The current shortcomings in biomass processing are inefficient fermentation of plant sugars, such as xylose, especially at high temperatures, lack of fermenting microbes that are able to resist inhibitors associated with pre-treated plant material and lack of effective lignocellulolytic enzymes for complete hydrolysis of plant polysaccharides. Due to the presence of residual partially degraded lignocellulose in the gut, the dung of herbivores can be considered as a natural source of pre-treated lignocellulose. A total of 101 fungi were isolated (36 yeast and 65 mould isolates). Six yeast isolates produced ethanol during growth on xylose while three were able to grow at 42 °C. This is a desirable growth temperature as it is closer to that which is used during the cellulose hydrolysis process. From the yeast isolates, six isolates were able to tolerate 2 g/L acetic acid and one tolerated 2 g/L furfural in the growth media. These inhibitors are normally generated during the pre-treatment step. When grown on pre-treated thatch grass, Aspergillus species were dominant in secretion of endo-glucanase, xylanase and mannanase.

Influence of inlet water on the biotic and abiotic variables in a fish pond / Influência da água de entrada sobre as variáveis bióticas e abióticas em um viveiro de piscicultura

Abstract The effects of treated and untreated water inlets with macrophytes on the improvement of water quality and zooplankton community were evaluated in a fish pond with continuous water flow. Water and zooplankton samples were retrieved at four sites during nine months. There were differences (p<0.01) between inlet water from fish pond and inlet water from canal with macrophytes, featuring higher concentrations of nutrient load, mainly TAN and TP in the former. The inlet water from fish pond contained a higher number of abundant species (9 species), whilst the water supply from the canal with macrophytes had a greater richness (31 species) of zooplankton species. Results showed that inlet water without macrophytes directly affected the characteristics of the water column and the dominance of zooplankton species such as Thermocyclops decipiens, and greater abundance of Rotifera species. Since aquatic plants in the inlet water of fish pond analyzed showed lower allochthonous material loads from the previous fish pond, the management adopted with macrophytes may be applied to avoid eutrophication risks, common in farm ponds.

Resumo Os efeitos do abastecimento tratado e não tratado com macrófitas sobre a qualidade da água e comunidade zooplanctônica foram avaliados em um viveiro de piscicultura com fluxo contínuo de água. Houve maior concentração de fósforo total e nitrogênio amoniacal na água não tratada (p<0,01). Na água de entrada sem tratamento de macrófitas foi observado maior número de espécies abundantes (9 espécies), contudo, a entrada de água tratada com macrófitas apresentou maior riqueza de espécies (31 espécies) zooplanctônicas. Os resultados obtidos mostraram que a água de entrada sem macrófitas influenciou as características da coluna de água com predominância de espécies zooplanctônicas, como Thermocyclops decipiens e maior abundância de espécies de Rotifera. A água tratada com macrófita apresentou menor carga de materiais alóctones provenientes do viveiro anterior, indicando que o manejo adotado com macrófitas pode ser aplicado para evitar riscos de eutrofização, comuns em piscicultura.

Review: dietary phenolic compounds, health benefits and bioaccessibility

Phenolic compounds are ubiquitous in plant-based foods. High dietary intake of fruits, vegetables and cereals are related to a decreased rate in chronic diseases. Phenolic compounds are thought to be responsible, at least in part, for those health effects. Nonetheless, the bioaccessibility of phenolic compounds is not often considered in these studies; thus, a precise mechanism of action of phenolic compounds is not known. In this review, we aim to present a comprehensive knowledge of the potential health promotion effects of polyphenols and the importance of considering the factors that affect their bioavailability on research projects(AU)

Los compuestos fenólicos son ubicuos en alimentos de origen vegetal. La alta ingesta de frutas, vegetales y cereales está relacionada con un bajo índice en padecimientos crónicos. Se cree que los compuestos fenólicos son, en parte, responsables de este efecto benéfico. Sin embargo, la bioaccesibilidad y biotransformación de los compuestos fenólicos generalmente no es considerada en este tipo de estudios. Por lo tanto, no se ha podido obtener un mecanismo de acción de los compuestos fenólicos. En este trabajo, presentamos una revisión de literatura del potencial benéfico de los compuestos fenólicos y cómo diversos factores pueden afectar su absorción y metabolismo(AU)

Bioremediation of polyaromatic hydrocarbons (PAHs) using rhizosphere technology

The remediation of polluted sites has become a priority for society because of increase in quality of life standards and the awareness of environmental issues. Over the past few decades there has been avid interest in developing in situ strategies for remediation of environmental contaminants, because of the high economic cost of physicochemical strategies, the biological tools for remediation of these persistent pollutants is the better option. Major foci have been considered on persistent organic chemicals i.e. polyaromatic hydrocarbons (PAHs) due to their ubiquitous occurrence, recalcitrance, bioaccumulation potential and carcinogenic activity. Rhizoremediation, a specific type of phytoremediation that involves both plants and their associated rhizospheric microbes is the creative biotechnological approach that has been explored in this review. Moreover, in this review we showed the significance of rhizoremediation of PAHs from other bioremediation strategies i.e. natural attenuation, bioaugmentation and phytoremediation and also analyze certain environmental factor that may influence the rhizoremediation technique. Numerous bacterial species were reported to degrade variety of PAHs and most of them are isolated from contaminated soil, however few reports are available from non contaminated soil. Pseudomonas aeruginosa, Pseudomons fluoresens, Mycobacterium spp., Haemophilus spp., Rhodococcus spp., Paenibacillus spp. are some of the commonly studied PAH-degrading bacteria. Finally, exploring the molecular communication between plants and microbes, and exploiting this communication to achieve better results in the elimination of contaminants, is a fascinating area of research for future perspective.

Anaerobic decomposition of a native and an exotic submersed macrophyte in two tropical reservoirs / Decomposicao anaerobica de uma macrofita submersa nativa e de uma exotica em dois reservatorios tropicais

Some aquatic plants have fast metabolism and growth, even at sub-optimal conditions, and become dominant in lentic environments such as large reservoirs, altering the nutrient cycle and impairing their environmental quality. There is great need in the knowledge impact processes of invasive species in aquatic environments, among the major, those related to the decomposition. This study evaluated the anaerobic decomposition of invasive submerged macrophytes Egeria densa Planch, native, and Hydrilla verticillata (L.f.) Royle, exotic in Porto Primavera and Jupiá reservoirs, Paraná basin. We evaluated the decay of organic matter, humification degree of the leached material, electrical conductivity and pH of the decomposition process. Mathematical models were utilised to describe the decomposition patterns over time. Both species showed the same heterogeneous pattern of decay of organic matter and carbon mineralisation. The models of carbon mineralisation, compared with the experimentally obtained data presented were adequate. Both species show no significant differences in the decomposition processes. Incubations of both species presented rapid t ½ for POC mineralisation and low DOC mineralisation.

Algumas plantas aquáticas apresentam rápido metabolismo e desenvolvimento, mesmo em condições subótimas, tornando-se dominantes em ambientes lênticos, como em grandes reservatórios, alterando o ciclo de nutrientes e depreciando a qualidade ambiental. Existe grande necessidade do conhecimento das vias de impacto de espécies invasoras em ambientes aquáticos; dentre as principais, apontam-se as vias de impacto relacionadas à decomposição. Este estudo avaliou a decomposição anaeróbia das macrófitas submersas invasoras Egeria densa Planch., nativa, e da Hydrilla verticillata (Lf) Royle, exótica, nos Reservatórios de Porto Primavera e Jupiá, Bacia do Rio Paraná. Foram avaliados os seguintes aspectos: a decomposição da matéria orgânica, o grau de humificação do material lixiviado e a condutividade elétrica e o pH do processo de decomposição. Modelos matemáticos foram utilizados para descrever os padrões de decomposição ao longo do tempo. Ambas as espécies apresentaram o mesmo padrão heterogêneo de decomposição da matéria orgânica e mineralização do carbono. Os modelos de mineralização do carbono, em comparação com os dados obtidos experimentalmente, apresentaram boa convergência. As espécies não apresentaram diferenças significativas entre si nos processos de decomposição. As incubações das duas espécies apresentaram t½ rápido para a mineralização do COP e baixo, para a mineralização do COD.

Chemical characterization of bioactive compounds from the endophytic fungus Diaporthe helianthi isolated from Luehea divaricata

Endophytic microorganisms, defined as fungi or bacteria that colonize the interior of plants without causing any immediate negative effects or damages, have reciprocal relationships with host plants. In some cases their presence is beneficial to the host due to the synthesis of bioactive compounds, among which several alcohols, esters, ketones and others that may react with other compounds and may be lethal to pathogenic microorganisms. Diaporthe helianthi (Phomopsis helianthi in its anamorphic phase) is available worldwide, especially in Europe, Asia and America. Isolated in Europe as an agent of the sunflower stem cancer, it has also been endophytically isolated from tropical and temperate plants. A D. helianthi strain isolated from Luehea divaricata has been employed in current research. An investigation of the secondary metabolite from D. helianthi by CC and NMR of ¹H and 13C yielded the separation of 10 fractions and the identification of the phenolic compound 2(-4 hydroxyphenyl)-ethanol (Tyrosol). Its antimicrobial reaction was tested and the ensuing antagonistic effects on the human pathogenic bacteria Enterococcus hirae, Escherichia coli, Micrococcus luteus, Salmonella typhi, Staphylococcus aureus, phytopathogenic Xanthomonas asc. phaseoli and phytopathogenic fungi were demonstrated. Results show that bioactive compounds and Tyrosol produced by D. helianthi have a biotechnological potential.

Chemical Genomics in Plant Biology.

Chemical genomics is a newly emerged and rapidly progressing field in biology, where small chemical molecules bind specifically and reversibly to protein(s) to modulate their function(s), leading to the delineation and subsequent unravelling of biological processes. This approach overcomes problems like lethality and redundancy of classical genetics. Armed with the powerful techniques of combinatorial synthesis, high-throughput screening and target discovery chemical genomics expands its scope to diverse areas in biology. The well-established genetic system of Arabidopsis model allows chemical genomics to enter into the realm of plant biology exploring signaling pathways of growth regulators, endomembrane signaling cascades, plant defense mechanisms and many more events.

Climate change and its effects on terrestrial insects and herbivory patterns

Climate change and extreme weather events affect plants and animals and the direct impact of anthropogenic climate change has been documented extensively over the past years. In this review, I address the main consequences of elevated CO2 and O3 concentrations, elevated temperature and changes in rainfall patterns on the interactions between insects and their host plants. Because of their tight relationship with host plants, insect herbivores are expected to suffer direct and indirect effects of climate change through the changes experienced by their host plants, with consequences to population dynamics, community structure and ecosystem functioning.

Effect of glucose and lactose on uptake of phenol by lemna minor

Previous researches have demonstrated that presence of some carbohydrates in the culture medium will cause callus induction and frond regeneration in Lemna minor, and it is expected that presence of carbohydrates will affect the uptake of organics by this plant. However, limited studies have investigated the uptake of organics by this plant. The aim of this study was to clarify the effect of conventional carbohydrates such as glucose and lactose on uptake of phenol by Lemna- minor. Experiments were carried out in the presence and absence of glucose and lactose in the growth solution. The growth solution was fresh water collected from river and phenol was added to it. The initial concentrations of phenol were 20, 50 and 100 mg/L and density of Lemna minor [fresh weight] were 50, 100 and 150 g/m[2]. The plants were contacted with growth solutions for 4 weeks. Control bottles [without plants] were examined with the same manner. The bottles were placed under white cool light with 12h photo periods at room temperature. Every four days sample was taken and the concentration of phenol was determined by spectrophotometer. Uptake of phenol by lemna-minor increased with increasing the contact time and decreased by increasing phenol concentration. In the presence of glucose and lactose in the growth solutions, uptake of phenol was decreased. Phenol uptake was dependent to plant density and when Lemna minor completely covered the surface of the water, uptake decreased. In the presence of glucose and lactose, uptake of phenol by Lemna minor was decreased. Uptake of phenol by lemna minor was affected by density of plant