Chemical composition and biological activities of the essential oils from Lippia alba and Lippia origanoides.

There is an increasing interest in essential oils extracted from Verbenaceae plant species as potential sources of biologically active compounds that could provide a starting point for designing novel phyto-pharmaceuticals in aquaculture. The present study was aimed to investigate the chemical composition, antioxidant activity, acute toxicity and antimicrobial effects against Vibrio parahaemolyticus of essential oils extracted from Lippia alba and L. origanoides. Approximately 23 components were identified and quantified by gas chromatography-mass spectrometry and flame ionization detection in each species' essential oil. The most predominant compounds were geranial (23.0%), limonene (17.0%) and neral (15.5%) in L. alba, and thymol (47.2%), p-cymene (16.0%) and E-caryophyllene (11.3%) in L. origanoides. The essential oils have antibacterial activity against Vibrio parahaemolyticus presenting Minimum Inhibitory Concentration (MIC) and Bactericidal Concentration (MBC) values between 156-625 µg mL-1. The essential oils also show antioxidant potential estimated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging assays, presenting IC50 of 60.16 mg mL-1 and 0.22 mg mL-1 for L. alba and L. origanoides EO, respectively. Both oils were classified as toxic to Artemia salina nauplii. Therefore, these essential oils may be useful for controlling pathogenic bacteria important to the aquaculture industry.

Mitochondrial DNA Variation Reveals a Sharp Genetic Break within the Distribution of the Blue Land Crab Cardisoma guanhumi in the Western Central Atlantic.

The blue land crab Cardisoma guanhumi is widely distributed throughout tropical and subtropical estuarine regions in the Western Central Atlantic (WCA). Patterns of population genetic structure and historical demographics of the species were assessed by mtDNA control region sequence analysis to examine the connectivity among five populations (n = 97) within the region for future conservation strategies and decision-making of fishery management. A total of 234 polymorphic nucleotides were revealed within the sequence region, which have defined 93 distinct haplotypes. No dominant mtDNA haplotypes were found but instead a distribution of a few low-frequency recurrent haplotypes with a large number of singletons. A NJ-tree and a median-joining haplotype network revealed two distinct clusters, corresponding to individuals from estuaries located along the Caribbean Sea and Brazilian waters, respectively. AMOVA and FST statistics supported the hypothesis that two main geographic regions exists. Phylogeographical discontinuity was further demonstrated by the Bayesian assignment analysis and a significant pattern of isolation-by-distance. Additionally, tests of neutral evolution and analysis of mismatch distribution indicate a complex demographic history in the WCA, which corresponds to bottleneck and subsequent population growth. Overall, a sharp genetic break between Caribbean and Brazilian populations raised concerns over the conservation status of the blue land crab.

Aspectos bioecológicos e genético-comportamentais envolvidos na conservação da abelha Jandaíra, Melipona subnitida Ducke (Apidae, Meliponini), e o uso de ferramentas moleculares nos estudos de diversidade / Bioecological and behavioral genetic aspects involved in the conservation of the stingless bee Melipona subnitida Ducke (Apidae, Meliponini) and the use of molecular tools in studies of diversity

A abelha sem ferrão Melipona subnitida atualmente está presente em quase toda a região nordeste, em função da boa adaptabilidade ao semiárido nordestino e do potencial econômico-ecológico proporcionado pela produção de mel e pela polinização de cultivos em condições de confinamento. Apesar disso, é uma espécie ameaçada devido a processos de degradação ambiental, dentre os quais estão o desmatamento, o uso indiscriminado de agrotóxicos e o extrativismo. Tais interferências tendem a isolar as populações de Jandaíra, provocando uma queda na variabilidade genética e, consequentemente, uma redução na capacidade adaptativa da espécie. Porém, técnicas de biologia molecular estão sendo implementadas, possibilitando que populações desse tipo sejam avaliadas quanto ao seu grau de variabilidade genética. Marcadores moleculares do tipo microssatélites de DNA vêm sendo bastante usados, porém, em função do alto custo exigido para seu desenvolvimento, diversos estudos vêm empregando microssatélites transferidos de táxons próximos com amplo sucesso em estudos voltados à caracterização e à diversidade genética. Dessa forma, a presente revisão objetivou avaliar os mais relevantes aspectos bioecológicos e genético-comportamentais envolvidos na conservação da abelha Jandaíra, a fim de auxiliar na avaliação do grau de diversidade genética da espécie, bem como da sua distribuição entre indivíduos e populações da abelha sem ferrão M. subnitida.(AU)

The stingless bee Melipona subnitida is now present almost everywhere in the Brazilian Northeastern, as a consequence of its good adaptability to the semiarid and economic and ecological potential offered by the honey production and pollination of commercial crops under confined conditions. Nevertheless, it is an endangered species due to environmental degradation processes, among which are: deforestation, indiscriminate use of pesticides and honey extraction. Such interference tends to isolate populations of Jandaíra causing a decrease in genetic variability, and therefore a reduction in the adaptive capacity of the species. However, advanced Molecular Biology techniques have been used allowing such populations to be assessed for their degree of genetic variability. Molecular markers such as microsatellite DNA are widely applied to genetic diversity studies. However, due to the high costs required for their development, several studies have been focused on the use of microsatellites transferred from closely related taxa with much success in studies on the genetic characterization of species and their populations. Therefore, this review aimed to evaluate the most relevant ecological and behavioral aspects in order to assist the population genetic studies of the stingless bee M. subnitida.(AU)

Application of a double-enrichment procedure for microsatellite isolation and the use of tailed primers for high throughput genotyping

The number of microsatellite loci and their allelic diversity contribute to increase accuracy and informativity of genetic estimates, however, the isolation of microsatellite loci is not only laborious but also quite expensive. We used (GATA)n and (GACA)n tetranucleotide probes and single- and double-enrichment hybridization to construct and screen a genomic library with an increased proportion of DNA fragments containing repeat motifs. Repeats were found using both types of hybridization but the double-enrichment procedure recovered sequences of which 100 percent contained (GATA)n and (GACA)n motifs. Microsatellite loci primers were then designed with an M13R-tail or CAG-tag to produce scorable PCR products with minimal stutter. The approach used in this study suggests that double-enrichment is a worthwhile strategy when isolating repeat motifs from eukaryotic genomes. Moreover, the use of tailed microsatellite primers provides increased resolution for compound microsatellite loci, with a significant decrease in costs.