Micro-invertebrates conservation: forgotten biodiversity

The concern about the preservation of biodiversity is due, in part, to a great level of media coverage granted in the last few years to global warming and consequential climatic changes. However, there are still considerably large gaps in scientific knowledge regarding the ecological status of many species, which results in an absence of conservation strategy for most of Earth’s biodiversity in need of it. The extinction of many animal and plant species can have catastrophic consequences on the ecosystems’ balance and also in human well-being, resultant from the break of ecological services. To exemplify how a specific group of microscopic animals can be endangered, I have analyzed the case of the phylum Tardigrada. Tardigrades are microscopic animals that inhabit most environments: terrestrial, freshwater and marine. Even though many species are widespread and the terrestrial ones granted with cryptobiotic skills, they are adapted to each habitat type and, additionally, to local environmental patterns. This means that these tiny metazoans can be under significant environmental pressure in the various habitat types they are found in. The potential need of protective and compensatory measures aiming for appropriate conservation of these life forms is discussed, as is the need of studying for their objective elaboration.     

Design and synthesis of novel pyrimidine hydroxamic acid inhibitors of histone deacetylases

Inhibition of histone deacetylase activity represents a promising new modality in the treatment of a number of cancers. A novel HDAC series demonstrating inhibitory activity in cell proliferation assays is described. Optimisation based on the introduction of basic amine linkers to effect good drug distribution to tumour led to the identification of a compound with oral activity in a human colon cancer xenograft study associated with increased histone H3 acetylation in tumour tissue.     

Synthesis and evaluation of phenylequine for antimalarial activity in vitro and in vivo

Synthesis of the potent antiplasmodial 4-aminoquinoline, phenylequine (PQ), is reported for the first time. PQ and the two analogues show increased efficacy in moving from the chloroquine sensitive D10 to the chloroquine resistant K1 strain in vitro. The in vivo efficacy of PQ, and salts thereof, have been determined in Plasmodium berghei ANKA and Plasmodium yoelii. Phenylequine hydrochloride has shown an ED₅₀ of 0.81 in P. yoelii (cf chloroquine ED₅₀ = 1.31).     

An in vitro growth inhibition test for measuring the potency of Leptospira spp. Sejroe group vaccine in buffaloes

Leptospira spp. serovars Hardjo and Wollfi from Sejroe serogroup have been detected in livestock in Brazil, where the main control procedures rely on vaccination. The potency of two commercial vaccines available in this country was monitored by microagglutination test-MAT and in vitro growth inhibition test-GIT in serum samples from 33 female buffaloes divided into: G1-unvaccinated control; G2-vaccinated with Leptobac-6^® containing serovars Hardjo and Wolffi and G3-vaccinated with Triangle-9^® containing serovar Hardjo. G2 and G3 animals were vaccinated on day zero, and received a booster and two revaccinations on days 30, 210 and 390 and G1 animals received phosphate buffered saline. Serum samples were collected at 15-day intervals between days 0 and 60; and at 30-day intervals between days 60 and 540 and were tested by MAT and GIT with serovars Hardjo and Wolffi. G1 remained negative throughout the experiment. Both vaccines were able to induce agglutinating and growth inhibition antibodies. Six months after the last revaccination, all animals tested negative by MAT, but still were positive by GIT until the end of experimental period. GIT could be a good tool to evaluate the potency and to monitor antibodies responses of vaccines of Sejroe group serovars.     

Cloning and purification of recombinant proteins of Mycoplasma hyopneumoniae expressed in Escherichia coli

Mycoplasma hyopneumoniae, the etiological agent of swine enzootic pneumonia, is an important pathogen in the swine industry worldwide. Vaccination is the most cost-effective strategy for controlling and prevention of this disease. However, investigations on pathogenicity mechanisms as well as current serological detection methods and the development of new recombinant subunit vaccines are hampered by the lack of known and well characterized species-specific M. hyopneumoniae antigens. In this work, 54 predicted genes encoding proteins with potential to be used as subunit vaccine or antigens in diagnostic tests were selected, amplified by PCR and cloned into Escherichia coli expression vectors. Recombinant protein expression, solubility and yields were analyzed. The majority of the recombinant proteins were expressed in inclusion bodies. After solubilization with urea or N-lauroyl sarcosine, recombinant proteins were purified by Ni²⁺ affinity chromatography. This approach allowed purification of thirty recombinant M. hyopneumoniae proteins which will be evaluated as vaccine candidates and/or as antigens to be used in diagnostic tests.     

New insights into molecular evolution: prospects from the Barcode of Life Initiative (BOLI)

Geographic and temporal patterns of morphological and behavioral diversifications among species stimulated Darwin to propose a mechanism for evolutionary change through natural selection. Scientific developments have revealed an even more fundamental level of biological complexity: sequence variation in DNA. While genome projects yield spectacular insights into molecular evolution, they have targeted only a few species. In contrast, the Barcode of Life Initiative (BOLI) proposes a horizontal approach to genomics, examining short, standardized genome segments across the sweep of eukaryotic life, all 10 million species. BOLI will extend our understanding of evolution and speciation in varied ways. It will facilitate quantification of biological diversity by disclosing cryptic species and enabling a rapid survey of taxon diversity in groups that have hitherto received scant morphological examination. It will facilitate assignment of life history stages to known species and provide a first estimate of species ages. It will also reveal key features of the mitochondrial genome, because the evolutionary properties of barcodes relate to those in the mitochondrial genome as a whole, acting to flag taxonomic groups or species with unusual nucleotide composition or evolutionary rates. The growing volume of barcode records has revealed that sequence variability within species is generally much lower than divergence among species (barcoding gap), a pattern that occurs in diverse lineages, suggesting a pervasive evolutionary process. Low variability may reflect recurrent selective sweeps of favored mitochondrial variants propagating as single linkage units across species. If this hypothesis is substantiated, the implications are significant, particularly for our understanding of molecular evolution of mitochondrial DNA and its relationship with species delineation.     

Spatial and temporal variations of Dinophyceae in subtropical reservoirs in southern Brazil

Knowledge of dinoflagellate diversity in Brazilian reservoirs is limited, especially in subtropical environments. We investigated as to how nutrients and other environmental variables influenced the biomass of Dinophyceae species in three subtropical ecosystems. The reservoirs Samuara, Faxinal, and São Miguel were sampled fortnightly from 2002 to 2006, and eight dinoflagellate taxa were identified. High temperature was a determining factor for the occurrence of Peridinium africanum Lemmermann. Peridinium umbonatum Stein and P. willei Huitfeld-Kass required high concentrations of nutrients. P. willei was inversely related to temperature and directly related to nutrients. P. umbonatum Stein var. umbonatum Stein showed the largest range of tolerance toward resources. Durinskia baltica Carty &; Cox and Peridinium gatunense Nygaard could be opportunistic, since they did not show any spatial or temporal pattern.