The Plastid Casein Kinase 2 Phosphorylates Rubisco Activase at the Thr-78 Site but Is Not Essential for Regulation of Rubisco Activation State

Rubisco activase (RCA) is essential for the activation of Rubisco, the carboxylating enzyme of photosynthesis. In Arabidopsis, RCA is composed of a large RCAα and small RCAβ isoform that are formed by alternative splicing of a single gene (At2g39730). The activity of Rubisco is controlled in response to changes in irradiance by regulation of RCA activity, which is known to involve a redox-sensitive disulfide bond located in the carboxy-terminal extension of the RCAα subunit. Additionally, phosphorylation of RCA threonine-78 (Thr-78) has been reported to occur in the dark suggesting that phosphorylation may also be associated with dark-inactivation of RCA and deactivation of Rubisco. In the present study, we developed site-specific antibodies to monitor phosphorylation of RCA at the Thr-78 site and used non-reducing SDS-PAGE to monitor the redox status of the RCAα subunit. By immunoblotting, phosphorylation of both RCA isoforms occurred at low light and in the dark and feeding peroxide or DTT to leaf segments indicated that redox status of the chloroplast stroma was a critical factor controlling RCA phosphorylation. Use of a knockout mutant identified the plastid-targeted casein kinase 2 (cpCK2α) as the major protein kinase involved in RCA phosphorylation. Studies with recombinant cpCK2α and synthetic peptide substrates identified acidic residues at the –1, +2, and +3 positions surrounding Thr-78 as strong positive recognition elements. The cpck2 knockout mutant had strongly reduced phosphorylation at the Thr-78 site but was similar to wild type plants in terms of induction kinetics of photosynthesis following transfer from darkness or low light to high light, suggesting that if phosphorylation of RCA Thr-78 plays a direct role it would be redundant to redox regulation for control of Rubisco activation state under normal conditions

Psychoative herbs commercialized in streets of Diadema (SP, Brazil): risk in its consumption

O comércio popular de drogas vegetais sem a garantia da qualidade implica em risco sanitário. O presente estudo fez uma análise interdisciplinar da rede de comércio de drogas vegetais (DVs) com foco nas drogas vegetais psicoativas (DVPs), disponíveis no comércio popular da Cidade de Diadema, e os riscos associados ao seu consumo. Métodos da etnofarmacologia, tais como: entrevistas informais, semi-estruturadas e observação participante foram utilizados para a realização do trabalho de campo; durante o qual, selecionaram-se quatro comerciantes, a fim de registrar a obtenção, manipulação, acondicionamento e tipos de DVs comercializadas. Foram registradas 63 DVs que remetiam a atividade psicoativa (DVPs) e, categorizadas em estimulantes (67%), depressoras (27%), depressoras e estimulantes (1%) e finalmente algumas não puderam ser definidas (5%). Essas DVPs tiveram seus nomes populares, forma de preparo e uso, partes utilizadas, contraindicações e doses registradas. Dezoito das 63 DVPs foram selecionadas segundo critérios do estudo, e seus lotes foram adquiridos dos entrevistados, a fim de serem analisados pela microbiologia (61 lotes) e farmacognosia (somente 22 daqueles, referentes a apenas 8 DVPs). Os resultados obtidos por essas áreas, somados a consultas em literaturas científicas, acerca de descrições de reações adversas, serviram de subsídio para a análise final dessas DVPs no contexto da farmacovigilância. Observaram-se deficiências principalmente na manipulação e acondicionamento das DVs por parte dos comerciantes, favorecendo sua contaminação e degradação. Os resultados das análises microbiológicas detectaram que 16% das DVPs analisadas apresentaram populações de bactérias (aeróbias e enterobactérias) superiores a 105 UFC/g e 31%, populações de fungos (bolores e leveduras) superiores a 103 UFC/g e a presença de espécies microbianas indicadoras de risco em 17 DVPs, especificamente em 74% dos 61 lotes, além de fungos produtores de aflatoxinas B1 e/ou B2 em quatro deles. Os resultados da farmacognosia demonstraram que 73% dos lotes foram reprovados ao menos em um dos demais parâmetros analisados (presença de contaminantes, caracterização e perfil cromatográfico). Sendo que, 50% dos 22 lotes analisados não coincidem com as especificações da farmacopéia e 36% apresentaram contaminação por outros órgãos vegetais, superior ao permitido nas monografias e um lote apresentou contaminação por insetos. Todos os 22 lotes foram reprovados na avaliação do rótulo (nomenclatura e validade) e praticamente todas as embalagens foram consideradas inadequadas. Além dos dados obtidos nessas análises, descrições de contra-indicações, efeitos adversos e interações medicamentosas foram encontradas na literatura científica para as 3 DVPs que tiveram sua identidade confirmada pela farmacognosia (camomila, ginkgo biloba e guaraná). Os resultados obtidos nesse estudo possibilitam observar as prioridades de adequação sanitária do comércio popular de DVs, bem como, traçar um perfil da qualidade das DVPs comercializadas segundo os parâmetros analisados. Conclui-se que essas DVPs reúnem importantes fatores capazes de causar danos à saúde dos consumidores, especialmente para alguns grupos como gestantes e indivíduos imunossuprimidos.The popular trade of herbal drugs without quality assurance implies a health risk. This study was an interdisciplinary analysis of the herbal drugs (DVs) trade network with focus on psychoactive drug plant (DVPs) available on the Brazilian city of Diadema, and risks associated with its consumption. Methods of ethnopharmacology, such as informal interviews, semi-structured interviews and participant observation were used for the completion of the fieldwork, during which four tradesmen were selected to register the collection, handling, packaging and types of DVs marketed. We registered 63 DVs that referred to psychoactive activity (DVPs) and categorized as stimulants (67%), depressants (27%), depressants and stimulants (1%) and finally some could not be set (5%). These DVPs had their popular names, preparations and uses, used parts, contraindications, and doses recorded. Eighteen of the 63 DVPs were selected according to the study criteria, and their lots were purchased by the selected tradesmen to be examined by microbiology (61 lots) and Pharmacognosy (only 22 of those lots, related to only 8 DVPs). The results for these areas, together with query in the scientific literature concerning descriptions of adverse reactions, provided the grant for the final analysis of these DVPs in the context of pharmacovigilance. Deficiencies were observed mainly in the handling and packaging of DVs by the traders, favoring its contamination and degradation. The microbiological analysis found that 16% of DVPs analyzed showed populations of bacteria (aerobic and Enterobacteriaceae) exceeding 105 CFU/g and 31%, populations of fungi (molds and yeasts) exceeding 103 CFU/g and the presence of risk indicator microbial species in 17 DVPs, specifically in 74% of the 61 lots, in addition to aflatoxin B1 or B2 producing fungi in four of them. The results of pharmacognosy showed that 73% had failed at least one of the parameters (contaminants, characterization and chromatographic profile), 50% of the 22 lots analyzed did not match the specifications of the pharmacopoeia, 36% were contaminated by other plant organs than those permitted in the monographs and a lot contamination by insects was found. All 22 lots have been disapproved in the evaluation of the label (classification and validity) and virtually all packages were considered inadequate. In addition to data obtained from such analysis, descriptions of contraindications, adverse effects and drug interactions were found in the literature for 3 DVPs who had their identity confirmed by the Pharmacognosy (chamomile, ginkgo biloba and guarana). The results obtained here allow us to observe the priorities of sanitary adequacy of the DVs popular trade, as well as establishing a profile of quality of DVPs marketed according to the analyzed parameters. We conclude that these DVPs gather important factors that could cause damage to the consumers health, especially for some groups such as pregnant women and immunosuppressed individuals.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)TEDEBV UNIFESP: Teses e dissertaçõe

The \u3cem\u3eChlamydomonas\u3c/em\u3e Genome Reveals the Evolution of Key Animal and Plant Functions

Chlamydomonas reinhardtii is a unicellular green alga whose lineage diverged from land plants over 1 billion years ago. It is a model system for studying chloroplast-based photosynthesis, as well as the structure, assembly, and function of eukaryotic flagella (cilia), which were inherited from the common ancestor of plants and animals, but lost in land plants. We sequenced the ∼120-megabase nuclear genome of Chlamydomonas and performed comparative phylogenomic analyses, identifying genes encoding uncharacterized proteins that are likely associated with the function and biogenesis of chloroplasts or eukaryotic flagella. Analyses of the Chlamydomonas genome advance our understanding of the ancestral eukaryotic cell, reveal previously unknown genes associated with photosynthetic and flagellar functions, and establish links between ciliopathy and the composition and function of flagella

A horizon scan of global conservation issues for 2014

This paper presents the output of our fifth annual horizon-scanning exercise, which aims to identify topics that increasingly may affect conservation of biological diversity, but have yet to be widely considered. A team of professional horizon scanners, researchers, practitioners, and a journalist identified 15 topics which were identified via an iterative, Delphi-like process. The 15 topics include a carbon market induced financial crash, rapid geographic expansion of macroalgal cultivation, genetic control of invasive species, probiotic therapy for amphibians, and an emerging snake fungal disease. © 2013 Elsevier Ltd

Heterogeneity in the physiological states and pharmacological responses of differentiating 3T3-L1 preadipocytes

A systems biology–based analysis shows that differentiating adipocytes look very different at the single-cell level and form distinct cellular subpopulations