A whole-body transcriptome assembly of the annelid worm Hediste diversicolor

The Annelida phylum is composed of a myriad of species exhibiting key phenotypic adaptations. They occupy key ecological niches in a variety of marine, freshwater and terrestrial ecosystems. Importantly, the increment of omic resources is rapidly modifying the taxonomic landscape and knowledge of species belonging to this phylum. Here, we comprehensively characterised and annotated a transcriptome of the common ragworm, Hediste diversicolor (OF Müller). This species belongs to the family Nereididae and inhabits estuarine and lagoon areas on the Atlantic coasts of Europe and North America. Ecologically, H. diversicolor plays an important role in benthic food webs. Given its commercial value, H. diversicolor is a promising candidate for aquaculture development and production in farming facilities, under a circular economy framework. We used Illumina next-generation sequencing technology, to produce a total of 105 million (M) paired-end (PE) raw reads and generate the first whole-body transcriptome assembly of H. diversicolor species. This high-quality transcriptome contains 69,335 transcripts with an N50 transcript length of 2313 bp and achieved a BUSCO gene completeness of 97.7% and 96% in Eukaryota and Metazoa lineage-specific profile libraries. Our findings offer a valuable resource for multiple biological applications using this species.

Seroprevalence of trypanosomosis and associated risk factors in cattle from coast and amazonian provinces of Ecuador

Trypanosomosis is a tropical disease caused by various protozoan haemoparasites, which affects wild and domestic animals, the latter ones related to worldwide livestock production systems. Species such as Trypanosoma vivax and Trypanosoma evansi have been described using serological and molecular tools in several countries from South and Central America. However, Ecuador presents a relevant knowledge gap in the associated general epidemiology and risk factors of the disease. Therefore, the objective of this study was to determine the seroprevalence of trypanosomosis in cattle from different regions of Ecuador. 745 serum samples from 7 Coastal and 3 Amazon provinces were screened for IgG anti-Trypanosoma spp. antibodies, using an in-house indirect ELISA. The seropositivity was explored and associated with several variables such as sex, age, breed, region, management, and province, using statistical tools. The general seroprevalence of trypanosomosis was 19.1% (95% CI: 16.30-22.1%). The Amazonian provinces of Sucumbíos and Napo and the Coastal province of Esmeraldas presented the highest seroprevalence values of 36.7% (95% CI: 27.67-46.47%), 23.64% (95% CI: 16.06-32.68%) and 25% (95% CI: 15.99-35.94%), respectively. Statistical significance was found for the region, province, and management variables, indicating as relevant risk factors the extensive management and Amazon location of the cattle analyzed. Specific actions should be taken to identify the exact species on reservoirs and susceptible hosts, evaluate the implication of farm management and cattle movement as risk factors, and implement surveillance and treatment plans for affected herds.

Functionalized Biochars as Supports for Ru/C Catalysts: Tunable and Efficient Materials for γ-Valerolactone Production

Cotton stalks-based biochars were prepared and used to synthetize Ru-supported catalysts for selective production of γ-valerolactone from levulinic acid in aqueous media. Different biochars' pre-treatments (HNO₃, ZnCl₂, CO₂ or a combination of them) were carried out to activate the final carbonaceous support. Nitric acid treatment resulted in microporous biochars with high surface area, whereas the chemical activation with ZnCl₂ substantially increases the mesoporous surface. The combination of both treatments led to a support with exceptional textural properties allowing the preparation of Ru/C catalyst with 1422 m²/g surface area, 1210 m²/g of it being a mesoporous surface. The impact of the biochars' pre-treatments on the catalytic performance of Ru-based catalysts is fully discussed.

Functional characterization reveals a diverse array of metazoan fatty acid biosynthesis genes

Long-chain (≥C₂₀ ) polyunsaturated fatty acids (LC-PUFAs) are physiologically important fatty acids for most animals, including humans. Although most LC-PUFA production occurs in aquatic primary producers such as microalgae, recent research indicates the ability of certain groups of (mainly marine) invertebrates for endogenous LC-PUFA biosynthesis and/or bioconversion from dietary precursors. The genetic pathways for and mechanisms behind LC-PUFA biosynthesis remain unknown in many invertebrates to date, especially in non-model species. However, the numerous genomic and transcriptomic resources currently available can contribute to our knowledge of the LC-PUFA biosynthetic capabilities of metazoans. Within our previously generated transcriptome of the benthic harpacticoid copepod Platychelipus littoralis, we detected expression of one methyl-end desaturase, one front-end desaturase, and seven elongases, key enzymes responsible for LC-PUFA biosynthesis. To demonstrate their functionality, we characterized eight of them using heterologous expression in yeast. The P. littoralis methyl-end desaturase has Δ15/17/19 desaturation activity, enabling biosynthesis of α-linolenic acid, eicosapentaenoic acid and docosahexaenoic acid (DHA) from 18:2 n-6, 20:4 n-6 and 22:5 n-6, respectively. Its front-end desaturase has Δ4 desaturation activity from 22:5 n-3 to DHA, implying that P. littoralis has multiple pathways to produce this physiologically important fatty acid. All studied P. littoralis elongases possess varying degrees of elongation activity for saturated and unsaturated fatty acids, producing aliphatic hydrocarbon chains with lengths of up to 30 carbons. Our investigation revealed a functionally diverse range of fatty acid biosynthesis genes in copepods, which highlights the need to scrutinize the role that primary consumers could perform in providing essential nutrients to upper trophic levels.

Molecular identification of Trypanosoma theileri in cattle from the Ecuadorian Amazon

Trypanosoma theileri is a cosmopolitan opportunistic haemoparasite described in wild and domestic ruminants, and also in arthropod vectors. The presence of this parasite has been reported in several South American countries, including Amazonian regions. Despite the importance of livestock production, Ecuador possesses scarce studies about trypanosomosis and no T. theileri reports in its territory. Here, we showed molecular evidences of the presence of T. theileri in cattle from a province located in the Ecuadorian Amazon. Bovine blood samples were collected from 2014 to 2019, during campaigns to detect haemoparasites in the Ecuadorian provinces of Orellana and Sucumbíos. DNA was extracted from the buffy coat and used in PCR assays with three different molecular markers, ITS1, 18S and Cathepsin L-like. T. theileri was detected only in the Sucumbíos province, with a specific molecular prevalence of 8.6% (3/35) using the three primers and an additional animal detected as positive (11.4% prevalence) only by the ITS1 marker. DNA sequences derived from the generated amplicons were subjected to phylogenetics maximum parsimony and maximum likelihood analysis, which indicate the presence of TthI and TthII genotypes circulating in the evaluated animals. Molecular surveillance should be continually implemented in Ecuador in order to deepen the epidemiological and evolutionary knowledge about T. theileri as well other haemoparasites in the amazon parts of the country.

The Re-Identification of Previously Unidentifiable Clinical Non-Tuberculous Mycobacterial Isolates Shows Great Species Diversity and the Presence of Other Acid-Fast Genera

Non-tuberculous mycobacteria that cannot be identified at the species level represent a challenge for clinical laboratories, as proper species assignment is key to implementing successful treatments or epidemiological studies. We re-identified forty-eight isolates of Ziehl-Neelsen (ZN)-staining-positive "acid-fast bacilli" (AFB), which were isolated in a clinical laboratory and previously identified as Mycobacterium species but were unidentifiable at the species level with the hsp65 PCR restriction fragment length polymorphism analysis (PRA). As most isolates also could not be identified confidently via 16S, hsp65, or rpoB DNA sequencing and a nBLAST search analysis, we employed a phylogenetic method for their identification using the sequences of the 16S rDNA, which resulted in the identification of most AFB and a Mycobacterium species diversity not found before in our laboratory. Most were rare species with only a few clinical reports. Moreover, although selected with the ZN staining as AFB, not all isolates belonged to the genus Mycobacterium, and we report for the first time in Latin America the isolation of Nocardia puris, Tsukamurella pulmosis, and Gordonia sputi from sputum samples of symptomatic patients. We conclude that ZN staining does not differentiate between the genus Mycobacterium and other genera of AFB. Moreover, there is a need for a simple and more accurate tree-based identification method for mycobacterial species. For this purpose, and in development in our lab, is a web-based identification system using a phylogenetic analysis (including all AFB genera) based on 16S rDNA sequences (and in the future multigene datasets) and the closest relatives.

Metabolic and molecular evidence for long-chain PUFA biosynthesis capacity in the grass carp Ctenopharyngodon idella

There is a growing interest to understand the capacity of farmed fish species to biosynthesise the physiologically important long-chain (≥C₂₀) n-3 and n-6 polyunsaturated fatty acids (LC-PUFAs), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and arachidonic acid (ARA), from their C₁₈ PUFA precursors available in the diet. In fish, the LC-PUFA biosynthesis pathways involve sequential desaturation and elongation reactions from α-linolenic acid (ALA) and linoleic acid (LA), catalysed by fatty acyl desaturases (Fads) and elongation of very long-chain fatty acids (Elovl) proteins. Our current understanding of the grass carp (Ctenopharyngodon idella) LC-PUFA biosynthetic capacity is limited despite representing the most farmed finfish produced worldwide. To address this knowledge gap, this study first aimed at characterising molecularly and functionally three genes (fads2, elovl5 and elovl2) with putative roles in LC-PUFA biosynthesis. Using an in vitro yeast-based system, we found that grass carp Fads2 possesses ∆8 and ∆5 desaturase activities, with ∆6 ability to desaturase not only the C₁₈ PUFA precursors (ALA and LA) but also 24:5n-3 to 24:6n-3, a key intermediate to obtain DHA through the "Sprecher pathway". Additionally, the Elovl5 showed capacity to elongate C₁₈ and C₂₀ PUFA substrates, whereas Elovl2 was more active over C₂₀ and C₂₂. Collectively, the molecular cloning and functional characterisation of fads2, elovl5 and elovl2 demonstrated that the grass carp has all the enzymatic activities required to obtain ARA, EPA and DHA from LA and ALA. Importantly, the hepatocytes incubated with radiolabelled fatty acids confirmed the yeast-based results and demonstrated that these enzymes are functionally active.

Dietary protein:lipid ratio modulates somatic growth and expression of genes involved in somatic growth, lipid metabolism and food intake in Pejerrey fry (Odontesthes bonariensis)

Pejerrey is a freshwater fish from South America with high potential for aquaculture. This study was designed to determine the effects of different dietary protein:lipid ratio on growth rate and the expression of growth, lipid metabolism and feeding-related genes of this species during early developmental stages. Pejerrey fry were fed for 60 days with four experimental diets containing low (400 g Kg^-1) or high (500 g Kg^-1) protein (LP or HP, respectively) and low (120 g Kg^-1) or high (200 g Kg^-1) lipid (LL or HL, respectively), in the combinations: LP-LL; LP-HL; HP-LL and HP-HL. Measurements of growth, lipid and fatty acid content of fry, expression of genes from the endocrine axis (gh, ghrs, igfs), fatty acid metabolism (∆6-desaturase), and food intake behavior (nucb2/nesfatin-1) were collected. Fry fed with diets LP-LL and HP-LL showed the highest growth rate and growth hormone (gh) mRNA expression levels. The gene expression of ∆6-desaturase was high in head of fry fed with diet LP-HL. The mRNA expression of nucb2/nesfatin-1 and gh followed the same patterns in head, and the inverse pattern in body. In conclusion, diets with LL ensure a higher growth of pejerrey fry compared to those that contain HL, without altering the final lipid amount nor the fatty acid profile on fry. In LL groups, the expression of genes from the GH-IGF axis is associated with the observed promotion of somatic growth. The expression of nucb2/nesfatin-1 indicates an effect of this peptide not related to food intake regulation, e.g., a negative regulatory role on GH expression, that would warrant future research.

Plasmonic Titanium Nitride Tubes Decorated with Ru Nanoparticles as Photo-Thermal Catalyst for CO2 Methanation

Photo-thermal catalysis has recently emerged as a viable strategy to produce solar fuels or chemicals using sunlight. In particular, nanostructures featuring localized surface plasmon resonance (LSPR) hold great promise as photo-thermal catalysts given their ability to convert light into heat. In this regard, traditional plasmonic materials include gold (Au) or silver (Ag), but in the last years, transition metal nitrides have been proposed as a cost-efficient alternative. Herein, we demonstrate that titanium nitride (TiN) tubes derived from the nitridation of TiO₂ precursor display excellent light absorption properties thanks to their intense LSPR band in the visible–IR regions. Upon deposition of Ru nanoparticles (NPs), Ru-TiN tubes exhibit high activity towards the photo-thermal CO₂ reduction reaction, achieving remarkable methane (CH₄) production rates up to 1200 mmol g⁻¹ h⁻¹. Mechanistic studies suggest that the reaction pathway is dominated by thermal effects thanks to the effective light-to-heat conversion of Ru-TiN tubes. This work will serve as a basis for future research on new plasmonic structures for photo-thermal applications in catalysis.

Biosynthesis of LC-PUFAs and VLC-PUFAs in Pampus argenteus: Characterization of Elovl4 Elongases and Regulation under Acute Salinity

Salinity has been demonstrated to influence the biosynthesis of long-chain (C_20-24) polyunsaturated fatty acids (LC-PUFAs) in teleost fish. Since LC-PUFAs are essential nutrients for vertebrates, it is central to understand how fish cope with an acute change in salinity associated with natural events. We herein report on the cloning and functional characterization of two elongation of very-long-chain fatty acid (Elovl)4 proteins, namely, Elovl4a and Elovl4b, and study the roles that these enzymes play in the biosynthesis of LC-PUFAs and very-long-chain (>C₂₄) polyunsaturated fatty acids (VLC-PUFAs) in marine teleost Pampus argenteus. The P. argenteus Elovl4 displayed all of the typical features of Elovl-like enzymes and have eyes and brain as major sites through which they exert their functions. Moreover, functional studies showed that the P. argenteus Elovl4 can effectively elongate C_18-22 substrates to C₃₆ VLC-PUFA. Because both P. argenteus Elovl4 are able to produce 24:5n - 3 from shorter precursors, we tested whether the previously reported Δ6 Fads2 from P. argenteus was able to desaturate 24:5n - 3 to 24:6n - 3, a key step for docosahexaenoic acid (DHA) synthesis. Our results showed that P. argenteus can indeed bioconvert 24:5n - 3 into 24:6n - 3, suggesting that P. argenteus has the enzymatic capacity required for DHA biosynthesis through the coordinated action of both Elovl4 and Fads2. Furthermore, an acute salinity test indicated that low-salinity stress (12 ppt) upregulated genes involved in LC-PUFA biosynthesis, with 12 ppt salinity treatment showing the highest hepatic LC-PUFA content. Overall, our results unveiled that the newly characterized Elovl4 enzymes have indispensable functions in LC- and VLC-PUFA biosynthesis. Moreover, acute salinity change influenced the biosynthesis of LC-PUFA in P. argenteus. This study provided new insight into the biosynthesis of LC- and VLC-PUFAs in vertebrates and the physiological responses that teleosts have under acute salinity stress.

Identification of new, very long-chain polyunsaturated fatty acids in fish by gas chromatography coupled to quadrupole/time-of-flight mass spectrometry with atmospheric pressure chemical ionization

The characterization of very long-chain (>C24) polyunsaturated fatty acids (VLC-PUFAs), which are essential in the vision, neural function, and reproduction of vertebrates, is challenging because of the lack of reference standards and their very low concentrations in certain lipid classes. In this research, we have developed a new methodology for VLC-PUFA identification based on gas chromatography coupled to quadrupole/time-of-flight mass spectrometry with an atmospheric pressure chemical ionization source (GC-APCI-QTOF MS). The mass accuracy attainable with the innovative QTOF instrument, together with the soft ionization of the APCI source, provides valuable information on the intact molecule, traditionally lost with electron ionization sources due to the extensive fragmentation suffered. We have identified, for the first time, VLC-PUFAs with chains up to 44 carbons in eyes, brain, and gonads of gilthead sea bream, a commercially important fish in the Mediterranean. The added value of ion mobility-mass spectrometry (IMS), recently developed in combination with GC-QTOF MS, and the contribution of the collisional cross section (CCS) parameter in the characterization of novel VLC-PUFAs (for which reference standards are not available) have been also evaluated. The methodology developed has allowed assessing qualitative differences between farmed and wild fish, and opens new perspectives in a still scarcely known field of research.

First ecotoxicological characterization of paraffin microparticles: a biomarker approach in a marine suspension-feeder, Mytilus sp

Microplastics are one of the main environmental pollutants in marine ecosystems, and their presence in seawater is a consequence of the widespread use of plastic materials in modern commodities. This wide usage of plastics includes the employment of microspheres in common personal care products, which end up being ultimately released into the aquatic compartment. Known ecotoxicological effects of microplastics favoured the search for technologically viable and environmentally safer alternatives, such as paraffin wax microparticles, whose ecotoxicological risks have not been entirely characterized. To address this gap, the present study exposed mussels (Mytilus sp.) for 96 h to three densities (5 mg/L, 20 mg/L and 80 mg/L) of four size ranges (100-300 μm, 300-500 μm, 400-850 μm, and 800-1200 μm) of paraffin wax particles. Toxicological endpoints were the activities of four enzymes involved in key cellular processes, including antioxidant defence (catalase (CAT), glutathione reductase (GRed) and glutathione peroxidase (GPx)) and phase II metabolism (glutathione S-transferases (GSTs)), as well as lipid content and fatty acid profiles of the digestive gland. Significant interactions between the presence/absence of food and paraffin particle density were found, as food sometimes worked as a confounding factor in the analysed biomarkers. Despite this uncertainty, some overall patterns emerged. In general, smaller paraffin wax particles (100-300 μm) caused little effects on the activity of the four enzymes tested, whereas larger particles (800-1200 μm) caused significant effects on almost all biomarkers. CAT activity was enhanced in animals exposed to larger paraffin particles, whilst GPx activity was depressed; GRed activity was not affected by the exposure to paraffin particles. The activity of GSTs was enhanced, but only in one tested condition. No effects were observed in terms of the total lipid content and fatty acids of exposed animals. Overall, data obtained in this work suggest that, at densities of paraffin wax particles comparable to the levels found in the environment for microplastic beads, no toxicity is expected to occur in the tested mussel species, by measuring the here-assessed toxicological endpoints.

Molecular and Functional Characterization of Elovl4 Genes in Sparus aurata and Solea senegalensis Pointing to a Critical Role in Very Long-Chain (>C24) Fatty Acid Synthesis during Early Neural Development of Fish

Very long-chain fatty acids (VLC-FA) play critical roles in neural tissues during the early development of vertebrates. However, studies on VLC-FA in fish are scarce. The biosynthesis of VLC-FA is mediated by elongation of very long-chain fatty acid 4 (Elovl4) proteins and, consequently, the complement and activity of these enzymes determines the capacity that a given species has for satisfying its physiological demands, in particular for the correct development of neurophysiological functions. The present study aimed to characterize and localize the expression of elovl4 genes from Sparus aurata and Solea senegalensis, as well as to determine the function of their encoded proteins. The results confirmed that both fish possess two distinct elovl4 genes, named elovl4a and elovl4b. Functional assays demonstrated that both Elovl4 isoforms had the capability to elongate long-chain (C_20–24), both saturated (SFA) and polyunsaturated (PUFA), fatty acid precursors to VLC-FA. In spite of their overlapping activity, Elovl4a was more active in VLC-SFA elongation, while Elovl4b had a preponderant elongation activity towards n-3 PUFA substrates, particularly in S. aurata, being additionally the only isoform that is capable of elongating docosahexaenoic acid (DHA). A preferential expression of elovl4 genes was measured in neural tissues, being elovl4a and elovl4b mRNAs mostly found in brain and eyes, respectively.

Cloning and functional characterization of an elovl4-like gene involved in the biosynthesis of long-chain polyunsaturated fatty acids in the swimming crab Portunus trituberculatus

Elongation of very long-chain fatty acid 4 (Elovl4) proteins participate in the biosynthesis of long-chain and very long-chain polyunsaturated fatty acids (LC-PUFA and VLC-PUFA). In the present study, an elovl4 cDNA was cloned from the swimming crab Portunus trituberculatus by PCR techniques and functionally characterized using recombinant expression in yeast Saccharomyces cerevisiae. The elovl4 cDNA sequence contained an open reading frame of 1038 base pairs, encoding a protein of 346 amino acids. The elovl4 has typical Elovl structures, with transmembrane domains (6) and a histidine box. The elovl4 was expressed in various tissues analyzed, with the highest expression found in intestine and hepatopancreas, followed by stomach and eyestalk. The functional characterization of Elovl4 yeast showed that the P. trituberculatus Elovl4 can elongate C_18-22 polyunsaturated fatty acids (PUFA), reaching in some cases products of C₂₄ and C₂₆. Along its ability to elongate PUFA, the P. trituberculatus Elovl4 was also efficient in the elongation of saturated fatty acids, with 28:0 and 30:0 being prominent elongation products. These results provide insight into the LC-PUFA biosynthetic capability of commercially important species of crustaceans.

Study of Aedes aegypti population with emphasis on the gonotrophic cycle length and identification of arboviruses: implications for vector management in cemeteries

Aedes aegypti is the vector of the arboviruses causing dengue, chikungunya and zika infections in Mexico. However, its presence in public places has not been fully evaluated. In a cemetery from Merida, Yucatan, Mexico, the productivity of Ae. aegypti, the gonotrophic cycle, and the presence of Ae. aegypti females infected with arboviruses were evaluated. Immature and adult mosquitoes were inspected every two months between April 2016 to June 2017. For the gonotrophic cycle length, the daily pattern of total and parous female ratio was registered and was analyzed using time series analysis. Ae. aegypti females were sorted into pools and assayed for flavivirus RNA by RT-PCR and Sanger sequencing. Aedes aegypti immatures represented 82.86% (8,627/10,411) of the collection. In total, 1,648 Ae. aegypti females were sorted into 166 pools. Two pools were positive; one for dengue virus (DENV-1) and the other for zika virus (ZIKV). The phylogenetic analysis revealed that the DENV-1 is more closely related to isolates from Brazil. While ZIKV is more closely related to the Asian lineage, which were isolates from Guatemala and Mexico. We report some evidence of vertical transmission of DENV-1 in nulliparous females of Ae. aegypti. The gonotrophic cycle was four and three days in the rainy and dry season, respectively. The cemetery of Merida is an important focus of Ae. aegypti proliferation, and these environments may play a role in arboviruses transmission; probably limiting the efficacy of attempts to suppress the presence of mosquitoes in domestic environments.

Effects of ibuprofen and carbamazepine on the ion transport system and fatty acid metabolism of temperature conditioned juveniles of Solea senegalensis

The increasing presence of pharmaceuticals in aquatic environments in the last decades, derived from human and veterinary use, has become an important environmental problem. Previous studies have shown that ibuprofen (IB) and carbamazepine (CBZ) modify physiological and biochemical processes in Senegalese sole (Solea senegalensis) in a temperature-dependent manner. In other vertebrates, there is evidence that both of these pharmaceuticals interfere with the 'arachidonic acid (AA) cascade', which is responsible for the biosynthesis of numerous enzymes that are involved in the osmoregulatory process. The present work aims to study the temperature-dependent effects of these two pharmaceuticals on several biochemical and molecular parameters in Senegalese sole. Regarding osmoregulation, Na⁺, K⁺ -ATPase enzyme activity was determined in the gills, kidney and intestine, and the expressions of both Na⁺, K⁺ -ATPase 1α-subunit isoforms (ATP1A1a and ATP1A1b) were quantified in gills. Gill prostaglandin-endoperoxide synthase-2 (PTGS2) gene expression and fatty acid composition were selected to determine the interference of both pharmaceuticals with the AA cascade. Senegalese sole juveniles, acclimatised at 15°C or 20°C, were exposed through intraperitoneal injection to IB (10mg/kg) and CBZ (1mg/kg) for 48h. Non-injected fish (Control) and those injected with the carrier (sunflower oil; S.O.), acclimated at each of the two temperatures, were used for comparison. The results show that IB directly affected the osmoregulatory mechanisms that alter gill and intestine Na⁺, K⁺ -ATPase activities. In addition, the copy number of ATP1A1a was higher at 20°C than at 15°C, which could be a direct response to the temperature variation. The gene expression of PTGS2 was affected by neither drug administration nor acclimation temperature. Nevertheless, detailed analysis of AA and eicosapentaenoic acid (EPA) percentages revealed a CBZ-derived effect in the fatty acid composition of the gills.

Blood Feeding Status, Gonotrophic Cycle and Survivorship of Aedes (Stegomyia) aegypti (L.) (Diptera: Culicidae) Caught in Churches from Merida, Yucatan, Mexico

Blood-feeding status, gonotrophic cycle, and survival rates of Aedes (Stegmyia) aegypti (L.) was investigated in catholic churches from Merida, Yucatan. Female Ae. aegypti were caught using backpack aspirator during 25 consecutive days in rainy (2015) and dry season (2016). Blood-feeding status was determined by external examination of the abdomen and classified as unfed, fed, and gravid. Daily changes in the parous-nulliparous ratio were recorded, and the gonotrophic cycle length was estimated by a time series analysis. Also, was observed the vitellogenesis to monitoring egg maturity. In total, 408 females Ae. aegypti were caught, and there was a significant difference in the number of females collected per season (Z = -6.729, P ≤ 0.05). A great number was caught in the rainy season (n = 329). In the dry season, 79 females were caught, which the fed females were twice greatest than the unfed. The length of gonotrophic cycle was estimated on the base of a high correlation coefficient value appearing every 4 days in rainy at 26.7 ± 1.22°C, and 3 days in dry season at 29.8 ± 1.47°C. The daily survival rate of the Ae. aegypti population was higher in both seasons, 0.94 and 0.93 for the rainy and dry season, respectively. The minimum time estimated for developing mature eggs after blood feeding was similar in both seasons (3.5 days in rainy versus 3.25 days in dry). The measurement of the vectorial capacity of Ae. aegypti in catholic churches could help to understand the dynamics of transmission of arboviruses in sites with high human aggregation.

Functional characterization and differential nutritional regulation of putative Elovl5 and Elovl4 elongases in large yellow croaker (Larimichthys crocea)

In the present study, two elongases, Elovl4 and Elovl5, were functionally characterized and their transcriptional regulation in response to n-3 LC-PUFA administration were investigated in vivo and in vitro. We previously described the molecular characterization of croaker elovl5. Here, we report the full-length cDNA sequence of croaker elovl4, which contained 1794 bp (excluding the polyA tail), including 909 bp of coding region that encoded a polypeptide of 302 amino acids possessing all the characteristic features of Elovl proteins. Functional studies showed that croaker Elovl5, displayed high elongation activity towards C₁₈ and C₂₀ PUFA, with only low activity towards C₂₂ PUFA. In contrast, croaker Elovl4 could effectively convert both C₂₀ and C₂₂ PUFA to longer polyenoic products up to C₃₄. n-3 LC-PUFA suppressed transcription of the two elongase genes, as well as srebp-1 and lxrα, major regulators of hepatic lipid metabolism. The results of dual-luciferase reporter assays and in vitro studies both indicated that the transcriptions of elovl5 and elovl4 elongases could be regulated by Lxrα. Moreover, Lxrα could mediate the transcription of elovl4 directly or indirectly through regulating the transcription of srebp-1. The above findings contribute further insight and understanding of the mechanisms regulating LC-PUFA biosynthesis in marine fish species.

Behind melanocortin antagonist overexpression in the zebrafish brain: A behavioral and transcriptomic approach

Melanocortin signaling is regulated by the binding of naturally occurring antagonists, agouti-signaling protein (ASIP) and agouti-related protein (AGRP) that compete with melanocortin peptides by binding to melanocortin receptors to regulate energy balance and growth. Using a transgenic model overexpressing ASIP, we studied the involvement of melanocortin system in the feeding behaviour, growth and stress response of zebrafish. Our data demonstrate that ASIP overexpression results in enhanced growth but not obesity. The differential growth is explained by increased food intake and feeding efficiency mediated by a differential sensitivity of the satiety system that seems to involve the cocaine- and amphetamine- related transcript (CART). Stress response was similar in both genotypes. Brain transcriptome of transgenic (ASIP) vs wild type (WT) fish was compared using microarrays. WT females and males exhibited 255 genes differentially expressed (DEG) but this difference was reduced to 31 after ASIP overexpression. Statistical analysis revealed 1122 DEG when considering only fish genotype but 1066 and 981 DEG when comparing ASIP males or females with their WT counterparts, respectively. Interaction between genotype and sex significantly affected the expression of 97 genes. Several neuronal systems involved in the control of food intake were identified which displayed a differential expression according to the genotype of the fish that unravelling the flow of melanocortinergic information through the central pathways that controls the energy balance. The information provided herein will help to elucidate new central systems involved in control of obesity and should be of invaluable use for sustaining fish production systems.

Aquatic pollution may favor the success of the invasive species A. franciscana

The genus Artemia consists of several bisexual and parthenogenetic sibling species. One of them, A. franciscana, originally restricted to the New World, becomes invasive when introduced into ecosystems out of its natural range of distribution. Invasiveness is anthropically favored by the use of cryptobiotic eggs in the aquaculture and pet trade. The mechanisms of out-competition of the autochthonous Artemia by the invader are still poorly understood. Ecological fitness may play a pivotal role, but other underlying biotic and abiotic factors may contribute. Since the presence of toxicants in hypersaline aquatic ecosystems has been documented, our aim here is to study the potential role of an organophosphate pesticide, chlorpyrifos, in a congeneric mechanism of competition between the bisexual A. franciscana (AF), and one of the Old World parthenogenetic siblings, A. parthenogenetica (PD). For this purpose we carried out life table experiments with both species, under different concentrations of the toxicant (0.1, 1 and 5μg/l), and analyzed the cholinesterase inhibition at different developmental stages. The results evidence that both, AF and PD, showed an elevated tolerance to high ranges of chlorpyrifos, but AF survived better and its fecundity was less affected by the exposure to the pesticide than that of PD. The higher fecundity of AF is a selective advantage in colonization processes leading to its establishment as NIS. Besides, under the potential selective pressure of abiotic factors, such as the presence of toxicants, its higher resistance in terms of survival and biological fitness also indicates out-competitive advantages.

[Mayaro: a re-emerging Arbovirus in Venezuela and Latin America]

Mayaro virus produces nonspecific, sublethal disease symptoms, often confused with dengue, but with symptoms of arthalgias that can cause incapacitating disability. Outbreaks have been localized and sporadic in the Pan-Amazonia forest since its first isolation in 1954 (Trinidad and Tobago). The literature available is scarce, diverse and dispersed. Mayaro virus is an alphavirus, phylogenetically related to the Semliki forest antigenic complex. UNA and Mayaro viruses are the only viruses of this complex that have been isolated in the New World. Mayaro consists of single-stranded RNA of positive charge, length of 12 kb, subdivided into genomic and subgenomic regions, which encode nonstructural and structural proteins respectively. Mayaro shows a great plasticity in vertebrate host infection, whereas high specificity in the family Culicidae (mosquitoes). Risk factors of infection are associated with forest areas of northern South America and the rainy season. Two genotypes of MAYV have been identified, L (Belterra, Brazil) and D (widely distributed in the Pan-Amazonia). The enzootic cycle is similar to the jungle cycle of yellow fever, which involves Haemagogus mosquitoes and monkeys as reservoirs. However, the involvement of other secondary vectors and other hosts may be important in spread of the virus. Humans may have high levels of viremia, and efficient experimental transmission has been demonstrated in Aedes aegypti, Aedes albopictus and Aedes scapularis, suggesting a significant risk to public health in urban, rural and peridomestic locations close to enzootic foci of Mayaro virus.

A revision of Artemia biodiversity in Macaronesia

In a biogeographical context, the term Macaronesia broadly embraces the North Atlantic archipelagos of the Azores, Madeira, Selvagens, the Canary Islands, and Cape Verde. The peculiar arid climatic conditions in some of these places have led to the development of marine salt exploitations, which can be counted among the hypersaline habitats of the brine shrimp Artemia (Branchiopoda, Anostraca). Parthenogenetic populations of this anostracan were described in the Canary Islands during the last decades of the 20th century, while the American Artemia franciscana species was recently found in the Cape Verde archipelago. Following an invasive pattern, this exotic species has recently reached the Canary Islands, too. This paper reports information dealing with biotope loss (solar saltworks) in this biogeographical region, together with possible consequences concerning the arrival of invasive species, two factors that frequently promote dramatic biodiversity losses. The discussion of this threat focuses mainly on the Canary Islands archipelago where native species of Artemia still exist.

New records of mosquitoes from northwestern Argentina

Eleven mosquito species, namely Aedes hastatus, Ae. fulvus, Coquillettidia albicosta, Cq. juxtamansonia, Culex aliciae, Cx. delpontei, Cx. oedipus, Cx. pedroi, Mansonia flaveola, Uranotaenia leucoptera, and Wyeomyia oblita, are recorded for the first time from northwestern Argentina. In addition, 3 species, Cx. brethesi, Limatus durhami, and Ur. nataliae, are reported for the first time from Salta Province. These records extend the geographical distribution of these 3 species to Salta Province. This study also extends the geographical distributions of Cq. nigricans, Cx. chidesteri, and Ma. humeralis to Jujuy Province and of Ae. meprai, Ae. milleri, Ae. oligopistus, Cx. brethesi, Cx. fernandezi, and Cx. tatoi to Tucumán Province.

Does exposure to testosterone significantly alter endogenous metabolism in the marine mussel Mytilus galloprovincialis?

Mussels (Mytilus galloprovincialis) were exposed to different concentrations of testosterone (T: 20, 200 and 2000ng/L) in a semi-static water regime (1-day dosing intervals) for up to 5 days in an attempt to see whether endogenous steroid levels and steroid metabolism were altered by exogenous exposure to testosterone. Whole tissue levels of total testosterone (free+esterified) sharply increased in a concentration-dependent manner, from 2ng/g in controls to 290ng/g in organisms exposed to the highest concentration. In contrast, levels of free testosterone were only significantly elevated at the high-exposure group (5-fold increase with respect to controls). Increased activity of palmitoyl-CoA:testosterone acyltransferase (ATAT) was detected in organisms exposed to the highest concentration of testosterone, while those exposed to low and medium concentrations showed significant alterations in their polyunsaturated fatty acid profiles. The obtained results suggest that esterification of the excess of T with fatty acids might act as a homeostatic mechanism to maintain endogenous levels of free T stable. Interestingly, a decrease in CYP3A-like activity was detected in T-exposed mussels together with a significant decrease in the metabolism of the androgen precursor androstenedione to dihydrotestosterone (5α-DHT). Overall, the work contributes to the better knowledge of androgen metabolism in mussels.

Effect of ivermectin on the liver of gilthead sea bream Sparus aurata: a proteomic approach

Gilthead sea bream Sparus aurata is the most commercialized Mediterranean aquacultured fish species. Ivermectin has recently (experimentally) started to be used to control ectoparasitic infestations in Mediterranean cultured marine fish. The potential hepatotoxicity of ivermectin was investigated in gilthead sea bream juveniles (35g) following oral administration at the recommended dose of 0.2 mgkg(-1) fish for 10d. Difference Gel Electrophoresis Technology (DIGE) was used to study the effect of this treatment in gilthead sea bream liver protein profile under routine culture conditions. The 2D-DIGE protein maps obtained were analyzed using the DeCyder 6.5 software. The results obtained showed significant changes in the expression of 36 proteins respect to the control group. Among these proteins, six increased in abundance, and 30 decreased. Spot showing differential expression respect to the control were analyzed by mass spectrometry and database search, which resulted in three positive identifications corresponding to hepatic proteins involved in lipid metabolism (apoA-I), oxidative stress responses and energy generation (beta-globin, ATP synthase subunit beta). These proteins have not been previously associated to invermectin effect.

Tissue-specific robustness of fatty acid signatures in cultured gilthead sea bream (Sparus aurata L.) fed practical diets with a combined high replacement of fish meal and fish oil

The present study aimed to determine the tissue-specific robustness of fatty acid (FA) signatures of gilthead sea bream (Sparus aurata L.) by analyzing the changes in lipid class and FA composition of skeletal muscle, brain, liver, and mesenteric adipose tissue. Triplicate groups of fish were fed to visual satiety over a 14-mo production cycle with 2 practical plant protein-based diets formulated with either fish oil or a blend of vegetable oils (66% of fish oil replacement) to contain 53% CP and 21% crude fat on a DM basis. Growth rates (P = 0.22) and tissue lipid class composition were not altered by the dietary treatment (P = 0.34 and 0.52 for neutral lipids and phospholipids, respectively). The FA signatures of neutral lipids reflected the composition of the diet, although the output of principal components analysis revealed a divergent FA profile for liver compared with skeletal muscle, brain, and mesenteric adipose tissue. Because the theoretical EFA needs were met by the 2 diets, the FA composition of phospholipids remained almost unaltered in all tissues. Interestingly, however, the brain showed the greatest robustness and regulatory capacity to preserve the phenotype of fish fed fish oil-based diets. The FA signatures of total lipids are a combinatory result of neutral and polar lipids, and the most relevant fat storage tissues (mesenteric adipose tissue and skeletal muscle) were more easily influenced by dietary FA composition. The present study provides new insights into fish tissue FA composition and reinforces the use of FA signatures as useful criteria in determining whether EFA requirements for a wide range of physiological processes, including those of neural tissues, can be met with practical fish feeds.

Triphenyltin alters lipid homeostasis in females of the ramshorn snail Marisa cornuarietis

Molluscs are sensitive species to the toxic effects of organotin compounds, particularly to masculinisation. Both tributyltin (TBT) and triphenyltin (TPT) have been recently shown to bind to mollusc retinoid X receptor (RXR). If RXR is involved in lipid homeostasis, exposure to TPT would have an immediate effect on endogenous lipids. To test this hypothesis, the ramshorn snail Marisa cornuarietis was exposed to environmentally relevant concentrations of TPT (30, 125, 500 ng/L as Sn) in a semi-static water regime for 7 days. Percentage of lipids and total fatty acid content decreased significantly in TPT-exposed females while the activity of peroxisomal acyl-CoA oxidase, involved in fatty acid catabolism, increased. In addition, fatty acid profiles (carbon chain length and unsaturation degree) were significantly altered in exposed females but not in males. This work highlights the ability of TPT to disrupt lipid metabolism in M. cornuarietis at environmentally realistic concentrations and the higher susceptibility of females in comparison to males.

A double-blind, placebo-controlled, randomized, multicenter study to investigate CHInese Medicine Neuroaid Efficacy on Stroke recovery (CHIMES Study)

Rationale Traditional Chinese Medications(TCM) have been reported to have beneficial effects in stroke patients, but were not rigorously evaluated by GCP standards. Aim This study tests the hypothesis that Neuroaid, a TCM widely used in China post-stroke, is superior to placebo in reducing neurological deficit and improving functional outcome in patients with acute cerebral infarction of an intermediate severity. Design This is a multicenter, randomised, double-blind, placebo-controlled study of Neuroaid in ischemic stroke patients with National Institute of Health Stroke Scale(NIHSS) 6-14 treated within 48 h of stroke onset. Neuroaid or placebo is taken (4 capsules) 3 times daily for 3 months. Treatments are assigned using block randomization, stratified for centers, via a central web-randomization system. With a power of 90% and two-sided test of 5% type I error, a sample size is 874. Allowing for a drop-out rate of up to 20%, 1100 individuals should be enrolled in this study. Study Outcomes The primary efficacy endpoint is the modified Rankin Scale(mRS) grades at 3 months. Secondary efficacy endpoints are the NIHSS score at 3 months; difference of NIHSS scores between baseline and 10 days, and between baseline and 3 months; difference of NIHSS sub-scores between baseline and 10 days, and between baseline and 3 months; mRS at 10 days, 1 month, and 3 months; Barthel index at 3 months; Mini Mental State Examination at 10 days and 3 months. Safety outcomes include complete blood count, renal and liver panels, and electrocardiogram.

STUDY REGISTRATION

ClinicalTrials.gov identifier: NCT00554723.

Bipolar disorders and quality of life: the impact of attention deficit/hyperactivity disorder and substance abuse in euthymic patients

Patients with bipolar disorders (BPD) display high rates of comorbidities, especially substance abuse (20-40%) and attention deficit/hyperactivity disorder (ADHD) (6%-20%). However, there are virtually no data evaluating the role of current ADHD on the global functioning of patients with BPD. The recent literature suggests that impairments in quality of life are a key prognostic feature for predicting the long course of BPD. The aim of this study was to investigate the intrinsic impact of adult ADHD and substance abuse in patients with BPD on levels of social adaptation, functioning and vitality. Seventy-three outpatients with BPD I or II, all euthymic and being treated with mood stabilizers, were evaluated using the following measures: 1) the Diagnostic Interview of Genetics Study for DSM-IV criteria; 2) the ADHD Self-Report Scale (ASRS) (screening of adult ADHD); 3) measures of quality of life: social adaptation (Social Adjustment Scale Self-Report (SAS-SR)), well-being (Short Form 36 (SF-36) Health Survey), and the Brief Psychiatric Rating Scale. In this clinical sample, 30% met the ADHD criteria and 22% were substance abusers. The results showed that the presence of ADHD in BPD patients significantly predicted a low social functioning and adaptation by comparison with BPD patients without ADHD. By contrast, we failed to detect a significant impact of substance abuse on those functional outcomes. This is the first step towards improved screening for comorbidities and an understanding of their crucial role in the prognosis of the disorder, as well as in defining new multilevel therapeutic strategies.

Acute toxicity of dichlorvos to Aphanius iberus (Cuvier & Valenciennes, 1846) and its anti-cholinesterase effects on this species

This study evaluates the toxic effects of the organophosphate pesticide (OP) dichlorvos to the endangered Iberian toothcarp (Aphanius iberus). To this end, the lethal toxicity of dichlorvos based on 96h-LC50 bioassays was determined in saline water (50g/L), and in vivo effects of dichlorvos on cholinesterase (ChE) activity were investigated in adult female and male specimens. The 96h-LC50 value determined by probit analysis was 3.17mg/L (95% confidence limits: 1.34-3.97). The characterisation of the ChE using different substrates and specific inhibitors was also carried out in head and muscle tissues. Acetylthiocholine was the substrate preferred by both head and muscle ChE in males and females. Eserine sulphate and BW284C51 significantly inhibited both head and muscle enzyme activity at low concentrations (muM range), and iso-OMPA had no significant effect. These results indicate that in the head and muscle the predominant ChE form is acetylcholinesterase (AChE) for both sexes. The kinetic parameters for ChE activity (Km and Vmax) were similar in both sexes. The 96h-LC50 value obtained for adult specimens of Iberian toothcarp was 3.17mg/L. ChE activity in head and body tissues of both sexes was significantly inhibited in all concentrations tested (0.5, 1, 2 and 4mg/L) after "in vivo" dichlorvos exposure. However, Iberian toothcarp was able to tolerate high concentrations of dichlorvos, and resist high levels of brain and muscle ChE inhibition without mortality. Both ChE inhibition and recovery followed a similar time-course pattern in response to sub-lethal exposure to dichlorvos (1mg/L), and the enzyme activity did not return to control levels after 96h in clean water. The results of this study show that ChE activity is a good biomarker of exposure to OP in the Iberian toothcarp adults.

Exposure to TBT increases accumulation of lipids and alters fatty acid homeostasis in the ramshorn snail Marisa cornuarietis

Recent studies have shown that organotin compounds affect lipid homeostasis in vertebrates, probably through interaction with RXR and/or PPARgamma receptors. Molluscs are sensitive species to the toxic effects of tributyltin (TBT), particularly to masculinization, and TBT has been recently shown to bind to molluscs RXR. Thus, we hypothesized that exposure to TBT could affect lipid homeostasis in the ramshorn snail Marisa cornuarietis. For comparative purposes, the synthetic androgen methyl-testosterone (MT) was included in the study due to its masculinization effects, but its lack of binding to the RXR receptor. M. cornuarietis was exposed to different concentrations of TBT (30, 125, 500 ng/L as Sn) and MT (30, 300 ng/L) for 100 days. Females exposed to 500 ng/L TBT showed increased percentage of lipids and increased levels of fatty acids in the digestive gland/gonad complex (2- to 3-fold). In addition, fatty acid profiles were altered in both males and females exposed to 125 and 500 ng/L TBT. These effects were not observed in females exposed to MT. Overall, this work suggest that TBT acts as a potent inducer of lipid and fatty acid accumulation in M. cornuarietis as shown in vertebrate studies earlier, and that sex differences in sensitivity do exist.

Assessment of the efficacy of Artemia sp (Crustacea) cysts chorion as barrier to chlorpyrifos (organophosphorus pesticide) exposure. Effect on hatching and survival

In order to reveal the efficacy of the Artemia cysts chorion as barrier to the organophosphorus pesticide chlorpyrifos, whole and decapsulated cysts have been exposed to 10 mg L(-1) chlorpyrifos in sea water during hydration and hatching phase, separately. The concentration of chlorpyrifos in capsulated and decapsulated cysts after exposure has been determined in order to elucidate the efficacy of chorion as protection to the embryo. The results obtained demonstrate the ability of the cysts chorion to obstruct the pass of chlorpyrifos molecules through this protection structure. Thus, the concentration of chlorpyrifos in exposed decapsulated cysts is higher than in exposed whole cysts. Moreover, after removing the chorion of exposed cysts, the concentration of chlorpyrifos in the embryo was lower than that of cysts exposed, what would demonstrate the retention of chlorpyrifos molecules by the shell. Hatching was not severely affected by exposure to the insecticide whereas survival at 44 h of the nauplii exposed to chlorpyrifos was significantly different from the controls. Survival of nauplii hatched from exposed decapsulated cysts was higher than that from those hatched from exposed whole cysts, probably because of the lower vitality of the latter, due to depletion of energy reserves during hatching.

Usefulness of procalcitonin levels in community-acquired pneumonia according to the patients outcome research team pneumonia severity index

STUDY OBJECTIVES

To evaluate the usefulness of procalcitonin serum levels as a predictor of etiology and prognosis in adult patients with community-acquired pneumonia (CAP) when they are stratified according to severity.

DESIGN

One-year, population-based, prospective study.

SETTING

University teaching hospital.

PATIENTS

All adult patients who received a diagnosis of CAP throughout the study period.

INTERVENTIONS AND MEASUREMENTS

An extensive noninvasive microbiological workup was performed. In patients who gave informed consent, a blood sample was collected at the time the diagnosis of CAP was established to measure biological markers. Procalcitonin levels were measured by a commercially available monoclonal immunoluminometric assay (limit of detection, 0.1 microg/L). Patients were classified according to microbial diagnosis, Patients Outcome Research Team pneumonia severity index (PSI), and outcome measures, and procalcitonin levels were compared among groups.

RESULTS

Of 240 patients who received a diagnosis of CAP during the study period, procalcitonin concentrations were measured in 185 patients (77.1%). Levels were higher in patients with high-severity risk classes (PSI classes III-V) [p = 0.01] and in those with complications (p = 0.03) or death (p < 0.0001). Among patients classified into PSI low-severity risk classes (classes I-II), levels tended to be higher in those with bacterial etiology (p = 0.08); in this group, a serum procalcitonin level > or = 0.15 microg/L was more frequently found in patients with bacterial pneumonia than in those with nonbacterial pneumonia (p = 0.03). In patients with higher-severity risk classes, no significant differences were observed in procalcitonin levels among etiologic groups, but higher concentrations were associated with development of complications (p = 0.01) and death (p < 0.0001).

CONCLUSIONS

Procalcitonin contribution to the evaluation of CAP varies according to severity. While procalcitonin may have a role to predict the microbial etiology in patients with a low PSI score, in patients classified within high PSI risk classes, it is a prognostic marker rather than a predictor of etiology.

Antioxidant enzyme activities and lipid peroxidation in the freshwater cladoceran Daphnia magna exposed to redox cycling compounds

Contaminant-related changes in antioxidative processes in the freshwater crustacea Daphnia magna exposed to model redox cycling contaminant were assessed. Activities of key antioxidant enzymes including catalase, superoxide dismutase, glutathione peroxidase and glutathione S-transferases and levels of lipid peroxidation measured as thiobarbituric acid-reactive substances (TBARS) and lipofucsin pigment content were determined in D. magna juveniles after being exposed to sublethal levels of menadione, paraquat, endosulfan, cadmium and copper for 48 h. Results denoted different patterns of antioxidant enzyme responses, suggesting that different toxicants may induce different antioxidant/prooxidant responses depending on their ability to produce reactive oxygen species and antioxidant enzymes to detoxify them. Low responses of antioxidant enzyme activities for menadione and endosulfan, associated with increasing levels of lipid peroxidation and enhanced levels of antioxidant enzyme activities for paraquat, seemed to prevent lipid peroxidation, whereas high levels of both antioxidant enzyme activities and lipid peroxidation were found for copper. For cadmium, low antioxidant enzyme responses coupled with negligible increases in lipid peroxidation indicated low potential for cadmium to alter the antioxidant/prooxidant status in Daphnia. Among the studied enzymes, total glutathione peroxidase, catalase and glutathione S-transferase appeared to be the most responsive biomarkers of oxidative stress.

Changes in antioxidant enzyme activities, fatty acid composition and lipid peroxidation in Daphnia magna during the aging process

Age-related changes in the balance between endogenous pro-oxidative and antioxidative processes in the freshwater cladoceran Daphnia magna (Crustacea) were assessed. The activities of key antioxidant enzymes including catalase, superoxide dismutase and glutathione peroxidase and levels of lipid peroxidation measured as thiobarbituric acid-reactive substances (TBARS) were determined in eight age classes, covering juvenile, young and senescent adults. Age-related changes in fatty acid composition were also measured to examine the contribution of polyunsaturated fatty acids (PUFA) in the peroxidation status of animals. Biochemical responses depicted in this study demonstrated that age-related decline in survival was accompanied by increasing oxidative stress and oxidative damage. Enhanced oxidative stress in aging D. magna was suggested by the significant increase in the formation of lipid peroxides, and a concomitant reduction of unsaturated fatty acids of 20 or more carbon atoms. Because aging was accompanied by selective loss of key antioxidant enzymes and small changes in the amount of PUFA, the breakdown of antioxidant defences might have directly contributed to oxidative stress, membrane lipid peroxide and a decline of survival. Indeed, the results reported here, indicate that age-related increases of lipid peroxides were at least partially due to the functional imbalance of enzymatic antioxidant defences.

Characterization of enzootic foci of Venezuelan equine encephalitis virus in western Venezuela

The distribution of the sylvatic subtype ID Venezuelan equine encephalitis (VEE) viruses in the lowland tropical forests of western Venezuela was investigated using remote sensing and geographic information system technologies. Landsat 5 Thematic Mapper satellite imagery was used to study the reflectance patterns of VEE endemic foci and to identify other locations with similar reflectance patterns. Enzootic VEE virus variants isolated during this study are the closest genetic relatives of the epizootic viruses that emerged in western Venezuela during 1992-1993. VEE virus surveillance was conducted by exposing sentinel hamsters to mosquito bites and trapping wild vertebrates in seven forests identified and located by means of the satellite image. We isolated VEE viruses from 48 of a total of 1,363 sentinel hamsters in two of the forests on six occasions, in both dry and wet seasons. None of the 12 small vertebrates captured in 8,190 trap-nights showed signs of previous VEE virus infection. The satellite image was classified into 13 validated classes of land use/vegetation using unsupervised and supervised techniques. Data derived from the image consisted of the raw digital values of near- and mid-infrared bands 4, 5, and 7, derived Tasseled Cap indices of wetness, greenness, and brightness, and the Normalized Difference Vegetation Index. Digitized maps provided ancillary data of elevation and soil geomorphology. Image enhancement was applied using Principal Component Analysis. A digital layer of roads together with georeferenced images was used to locate the study sites. A cluster analysis using the above data revealed two main groups of dense forests separated by spectral properties, altitude, and soil geomorphology. Virus was isolated more frequently from the forest type identified on flat flood plains of main rivers rather than the forest type found on the rolling hills of the study area. The spatial analysis suggests that mosquitoes carrying the enzootic viruses would reach 82-97% of the total land area by flying only 1-3 km from forests. We hypothesize that humans within that area are at risk of severe disease caused by enzootic ID VEE viruses. By contrast, equines could actually become naturally vaccinated, thus preventing the local emergence of epizootic IC VEE virus strains and protecting humans indirectly.

Comparison of PCR mediated amplification of DNA and the classical methods for detection of Mycobacterium leprae in different types of clinical samples in leprosy patients and contacts

Traditional staining and microscopic examination techniques for the detection of Mycobacterium leprae, DNA amplification by polymerase chain reaction (PCR) of a 531-bp fragment of the M. leprae specific gene encoding the 36-kDa antigen, and serodiagnosis with M. leprae specific antigens (PGL-1 and D-BSA) were compared on different clinical specimens (serum samples, slit-skin smears, biopsies and swabs) from 60 leprosy patients attending the Sanatorium of Fontilles. Patients were divided into groups; (i) 20 multibacillary patients (MB) with positive bacteriological index (BI) by conventional methods and on WHO multidrug therapy (MDT); (ii) 30 MB patients with negative BI and completed minimum 2 years treatment MDT; (iii) 10 paucibacillary (PB) patients who had completed 6 months MDT at least 8 years ago. Control groups included four non-leprosy patients for PCR methods and 40 health control patients and 10 tuberculosis patients for serological methods. In the multibacillary BI positive group, there was a good correlation between all methods. All tests were negative in the paucibacillary group, although only a few patients were tested and all had been treated many years ago. One must be cautious concerning the diagnostic potential of these techniques in this type of leprosy. We also studied different combinations of leprosy diagnosis methods to determine the potential risk in a leprosy contact individuals group. The prevalence of antibodies to M. leprae antigens in serum was measured, together with the presence of M. leprae DNA in the nose and lepromin status in a group of 43 contacts of leprosy patients (12 household and 31 occupational) to evaluate the maintenance of infection reservoirs and transmission of the disease. Only two individuals were found to form a potential high risk group.

Characterisation of cholinesterases and evaluation of the inhibitory potential of chlorpyrifos and dichlorvos to Artemia salina and Artemia parthenogenetica

In this study, the acute toxicity of the organophosphorous pesticides dichlorvos and chlorpyrifos to two different species of Artemia (A. salina and A. parthenogenetica) was evaluated. In addition, the in vivo effect of these two pesticides on cholinesterase (ChE) activity of both A. salina and A. parthenogenetica was also determined. The characterisation of the ChE, using different substrates and specific inhibitors, and the normal range of activity in non-exposed individuals were previously investigated for both species. The results obtained indicate that the ChE of A. salina is different from that of A. parthenogenetica and that both enzymes cannot be classified neither as acetylcholinesterase nor as butyrylcholinesterase since they show intermediary characteristics between the two vertebrate forms. The range of normal ChE activity was 2.65+/-0.15 U/mg protein for A. salina, and 3.69+/-0.17 U/mg protein for A. parthenogenetica. Significant in vivo effects of both pesticides on Artemia ChE activity were found, at concentrations between 5.38 and 9.30 mg/l for dichlorvos and between 1.85 and 3.19 mg/l for chlorpyrifos. Both Artemia species are resistant to these pesticides and they are able to survive with more than 80% ChE inhibition. However, A. parthenogenetica is more resistant than A. salina, with about a 95% reduction in its ChE activity respect to the control for nauplii exposed to the median lethal concentrations (LC50), without lethal effects after 24 h of exposure.

Bioaccumulation of chlorpyrifos through an experimental food chain: study of protein HSP70 as biomarker of sublethal stress in fish

The accumulation and transfer of the organophosphorus pesticide chlorpyrifos has been studied in an experimental aquatic two-level food chain using two species of the crustacean Artemia (A. franciscana and A. parthenogenetica) and the small fish Aphanius iberus. Artemia adults contaminated by exposure to the pesticide in water were used as live prey for Aphanius, the next trophic level. During the experimental bioaccumulation phase, fish were fed chlorpyrifos-contaminated Artemia pools with concentrations between 6.5 and 14.5 ng/g fresh weight for 32 days. Both concentrations accumulated in fish, and biomagnification factor (BMF) values showed a continuous decrease during the bioaccumulation phase, probably due to the physicochemical characteristics of the organophosphorus pesticide, to the biotransformation ability of fish and to the progressive adaptation of fish metabolism to toxic exposure. The first day that fish were fed uncontaminated preys, the pesticide accumulated via food was rapidly eliminated and was not detected. The effect of chlorpyrifos exposure through the food chain on stress protein (HSP70) synthesis was measured as a general biochemical response of stress in the fish (A. iberus). The levels of HSP70 were significantly higher in fish fed on contaminated Artemia than in the control fish fed on uncontaminated Artemia. Results showed that the HSP70 induction in fish could be associated to exposure of chlorpyrifos via food.

Genetic diversity and relationships among Venezuelan equine encephalitis virus field isolates from Colombia and Venezuela

During field studies of enzootic Venezuelan equine encephalitis (VEE) viruses associated with epizootic emergence, a large number of virus isolates were made in sylvatic foci of Venezuela and Colombia. To rapidly characterize these isolates, antigenic subtypes were determined by means of immunofluorescence and by single-strand conformational polymorphism (SSCP) analysis by use of an 856-bp fragment from the P62 gene, which we used to distinguish genetic variants. Representative isolates were sequenced to assess the sensitivity of SSCP to detect genetic differences. The SSCP analysis distinguished isolates differing by as little as 1 nucleotide; overall, differences of > or = 1 nucleotide were recognized 89% of the time, and the sensitivity to distinguish strains that differed by only 1 or 4 nucleotides was 17 and 57%, respectively. Phylogenetic analyses of representative sequences showed that all recent isolates from the Catatumbo region of western Venezuela and the middle Magdalena Valley of Colombia were closely related to epizootic subtype IAB and IC strains; strains from Yaracuy and Miranda States were more distantly related. Cocirculation of the same virus genotype in both Colombian and Venezuelan foci indicated that these viruses are readily transported between enzootic regions separated by > 300 km. The SSCP analysis appears to be a simple, fast, and relatively efficient method of screening VEE virus isolates to identify meaningful genetic variants.

Spatial dispersion of adult mosquitoes (Diptera: Culicidae) in a sylvatic focus of Venezuelan equine encephalitis virus

We studied the spatial localization of mosquitoes in sylvatic focus of Venezuelan equine encephalitis virus in western Venezuela to identify mosquito species potentially involved in the hypothesized transport of viruses out of enzootic foci. The following criteria were used to identify species with potential for virus export: (1) common in the forest and surrounding area, (2) feeding on a wide range of vertebrates; (3) long dispersal capabilities, and (4) established vectorial competence for enzootic or epizootic VEE viruses. CDC traps baited with light/CO2 were operated for four and 12-h intervals to collect mosquitoes at four stations along two forest/open area transects from September to November 1997. We collected 60,444 mosquitoes belonging to 11 genera and 34 species. The most common species were Aedes serratus (Theobald), Ae. scapularis (Rondani), Ae. fulvus (Wiedmann), Culex nigripalus Theobald, Cx, (Culex) "sp", Cx. mollis Dyar & Knab, Cx. spissipes (Theobald), Cx. pedroi Sirivanakarn and Belkin, Psorophora ferox (Humboldt), Ps. albipes (Theobald), and Ps. cingulata (F.). Very few mosquitoes were captured during the (day in the open area outside the forest, suggesting that any virus export from the forest may occur at night. The following mosquitoes seemed to be mostly restricted to the forest habitat: Ae. serratus, Ps. ferox, Ps. albipes, sabethines, Cx. spissipes, Cx. pedroi, Cx. dunni Dyar, and Ae. fulvus. The main species implicated its potential virus export were Cx. nigripalpus, Ae. scapularis, and Mansonia titillans (Walker).

Ecological studies of enzootic Venezuelan equine encephalitis in north-central Venezuela, 1997-1998

From 1997-1998, we investigated the possible continuous circulation of epizootic Venezuelan equine encephalitis (VEE) virus suggested by a 1983 subtype IC interepizootic mosquito isolate made in Panaquire, Miranda State, Venezuela. The study area was originally covered by lowland tropical rainforest but has been converted into cacao plantations. Sentinel hamsters, small mammal trapping, mosquito collections, and human serosurveys were used to detect active or recent virus circulation. Six strains of subtype ID VEE virus were isolated from hamsters that displayed no apparent disease. Four other arboviruses belonging to group A (Togaviridae: Alphavirus), two Bunyamwera group (Bunyaviridae), and three Gamboa group (Bunyaviridae) arboviruses were also isolated from hamsters, as well as 8 unidentified viruses. Venezuelan equine encephalitis-specific antibodies were detected in 5 small mammal species: Proechimys guairae, Marmosa spp., and Didelphis marsupialis. Mosquito collections comprised of 38 different species, including 8 members of the subgenus Culex (Melanoconion), did not yield any virus isolates. Sera from 195 humans, either workers in the cacao plantation or nearby residents, were all negative for VEE virus antibodies. Sequences of 1,677 nucleotides from the P62 gene of 2 virus isolates indicated that they represent a subtype ID lineage that is distinct from all others characterized previously, and are unrelated to epizootic VEE emergence.