Marine bioprospecting - Trawling for treasure and pleasure

This Microreview seeks to highlight the molecular diversity present in marine organisms, and illustrate by example some of the challenges encountered in exploring this resource. Marine natural products exhibit an impressive array of structural motifs, many of which are derived from biosynthetic pathways that are uniquely marine, Most importantly some marine metabolites possess noteworthy biological activities, activities that have potential application outside marine ecosystems, such as antibiotics, antiparasitics, anticancer agents etc... The isolation, spectroscopic characterisation and assignment of stereostructures to these unusual metabolites is both challenging and rewarding. Examples featured in this Microreview follow a common theme in that they are all recent accounts of the isolation of natural products from Australian marine sponges, carried out in the laboratories of the author. In addition to presenting brief comments on specific structure elucidation strategies, an effort is made to emphasize techniques for solving stereochemical issues, as well as to speculate on the biosynthetic origins of some of these exotic marine natural products.

Total synthesis of lamellarin D and analogs library

Larnellarins are a group of marine natural products isolated from the prosobranch mollusc Lamellaria sp., the ascidian Didemnum sp., and the sponge Dendrilla Cactos. Several of them exhibit interesting biological activities. Natural as well as synthetic lamellarins should be excellent candidates for the development of new drugs due to their unique skeletal structure and their important biological activities especially as antitumor agents. Lamelarin O has been recently characterized as a topoisomerase 1-targeted anti tumor agent. A variety of synthetic approaches have been developed for this family of alkaloids. Herein we describe a new route to the synthesis of Lamellarin D, from a methyl 2-pyrrolecarboxylate. Transformation of the starting material into the scaffold, a substituted 5,6-dihydropyrrolo (2,l ­a)isoquinoline (5,6-DHPl), was afforded by N-alkylation followed by intramolecular Heck cyclization. From this scaffold the synthetic strategy is based on two sequential regioselective bromination!Suzuki cross-coupling reactions which permitted the introduction of differently substituted aryl groups on positions 1 and 2 followed by oxidation, deprotection, and lactonization.

cis-3-hydroxy-N-methyl-L-proline: a new amino acid from a southern Australian marine sponge, Dendrilla sp.

A specimen of the sponge Dendrilla sp. collected during commercial trawling operations in the Great Australian Eight, Australia, analyses for a very high natural abundance of the new amino acid cis-3-hydroxy-N-methyl-L-proline (1). The complete stereostructure for (1) was determined by spectroscopic analysis and chemical derivatization.

Cactos

Ilustrações componentes do jogo “Escola Mágica (http://www.loa.sead.ufscar.br/escola-magica.html)” desenvolvido pela equipe do Laboratório de Objetos de Aprendizagem da Universidade Federal de São Carlos (LOA/UFSCar).

Germinação in vitro e desenvolvimento pós-seminal de plântulas de Pilosocereus aurisetus (Werderm.) Byles & G.D. Rowley (Cactaceae)

Pilosocereus aurisetus é uma espécie de cactos de importância econômica e ambiental que se encontra em risco de extinção. A propagação em áreas naturais ocorre, principalmente, de forma sexuada; entretanto, não há registro da germinação e viabilidade de sementes e morfologia pós-seminal de plântulas dessa espécie. Assim, objetivou-se avaliar a germinação de sementes e descrever a morfologia do desenvolvimento pós-seminal de plântulas de P. aurisetus. Para isso, sementes, armazenadas em condições ambientais por 19 meses, foram submetidas aos tratamentos: embebição em água por 24 horas; pré-resfriamento; imersão em solução de giberelina, nas concentrações de 250 mg L-1 e 500 mg L-1; e um tratamento controle. As sementes foram colocadas para germinar em meio de cultura MS, por 30 dias, quando se avaliou a percentagem de germinação. O delineamento estatístico foi o inteiramente casualizado, com cinco tratamentos e quatro repetições, sendo dispostas 25 sementes por parcela. A caracterização pós-seminal foi realizada por um período de 60 dias, utilizando-se microscópio binocular, com base nas Regras para Análise de Sementes. Maior percentagem da germinação de sementes ocorreu no controle, ou quando embebidas por 24 horas, sendo observados 90% e 83%, respectivamente. A morfologia do desenvolvimento pós-seminal indicou que a germinação é do tipo epígea, com hipocótilo de reserva; suas plântulas sofrem modificações na região do colo, para a emissão de raízes, e apresentam cerdas no ápice caulinar, mesmo na fase inicial da expansão cotiledonar. A diferenciação e início da formação das costelas iniciam-se aos 60 dias após a germinação, com o desenvolvimento do epicótilo.

Anatomia dos órgãos vegetativos de Cactaceae da caatinga pernambucana

Secções de raízes e cladódios de cinco espécies de Cactaceae ocorrentes em uma região de caatinga de Pernambuco (Harrisia adscendens (Gürke) Britton & Rose; Melocactus × horridus Wedermann Notizbl.; M. zenhtneri (Britton & Rose) Luetzelb.; Tacinga inamoena (Schumann) Taylor & Stuppy e T. palmadora (Britton & Rose) Taylor & Stuppy), foram analisadas para verificação de caracteres diagnósticos e adaptativos. As secções foram coradas com safranina e azul de astra e montadas em glicerina. As observações feitas mostraram que a estrutura interna das raízes é bastante similar não sendo observados caracteres diagnósticos. No xilema secundário das raízes ocorrem amplos raios pericíclicos representando um importante caracter adaptativo. O cladódio apresenta os seguintes caracteres diagnósticos e adaptativos: tipos de espinho; tipo e posição dos estômatos; estrutura da hipoderme; tipo e posição das estruturas mucilaginosas; aspecto geral do sistema vascular; ocorrência de feixes corticais e medulares; presença de cristais na epiderme e hipoderme e presença de parênquima aqüífero. Os resultados deste trabalho mostram que as espécies estudadas são cactos típicos apresentando caracteres, que podem ser responsáveis pelo sucesso destas plantas em ambientes adversos como a caatinga.

Órgãos reprodutivos em Hylocereeae e Rhipsalideae (Cactaceae): morfologia floral e desenvolvimento estrutural do fruto e da semente

Pós-graduação em Ciências Biológicas (Biologia Vegetal) - IBRC

Análise de sequências da região intergência ITS-1 do rDNA em espécies de Drosophila do cluster buzzatti, (complexo Buzzatti, subgrupo Mullerri, grupo Repleta). -

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Biologia reprodutiva de Mimus gilvus (Aves: Mimidae) em área de restinga no nordeste do Brasil

The thrush beach, Mimus gilvus (Aves: Mimidae) is a passerine widely distributed in Central and South America. In Brazil occurs mainly in the areas of the resting and vegetation near the beach. In southeastern Brazil this species has disappeared, mainly due to urbanization. Many attributes of their reproductive biology are unknown, especially in relation to reproductive success. During the years 2010-2011, 2011-2012 and 2014-2015 were made visits to the area of restinga forest in Centro de Lançamento da Barreira do Inferno (CLBI), located between the cities of Natal and Parnamirim-RN (5 ° 54'S 35 ° 10'W ) where they were made systematic searches to trying describe reproductive biology of the characteristics of M. gilvus, estimate their reproductive success using the Mayfield method, and identify the main factors that influence their reproductive success in environment the resting. For this, forty fifth active nests monitored were used. Only during the breeding season of 2011-2012 and 2014-2015 were made systematic visits to the study area. The reproductive period ranged August to March. Clutch size ranged from two, three and six eggs (n = 22). Broods of two eggs were more common, with an average of eggs laid per nest of 2 ± 0,51 (n = 20 nests). The incubation period was approximately 13 ± 1,9 days (n = 11 nests). The period of stay of the nestlings was approximately 11 ± 1,6 days (n = 9 nests). With approximately 11 days old the nestlings were able to leave the nest. The apparent success was 37,8% and the success estimated by Mayfield method was 26,6%. Predation was the main cause of loss of nests in the study area. The daily survival rates (TDS) were obtained from 0,9593 incubation and 0,9313 for nestling period respectively. Survival estimates for each period was 0,5827 for incubation and 0,4571 for nestling period. The cumulative average rainfall for each month influenced negatively the hatching rates of M. gilvus nests. In addition, the number hatch eggs among the most rainy season (rainy season) and the period of lowest rainfall (dry season) were different. The number of lost nests of M. gilvus was lower in scrubs than cactus, which may account for the largest number of nests of this species found in scrubs. Survival rates in nestling period were lower compared with the incubation period. The fact that the survival rates nests of M. gilvus be lower in the nestling period compared to the incubation period may result from increased activity of adults during this phase of the nest, which in turn would increase predation rates. M. gilvus seems to avoid the rainy season during their reproduction, concentrated most of their nests in periods of low rainfall.