Production of added value bacterial lipids through valorisation of hydrocarbon-contaminated cork waste

This work demonstrates that cork used as oil-spill sorbents, contaminated with liquid hydrocarbons, herein demonstrated with hexadecane, can be biologically treated by Rhodococcus opacus B4 with concomitant lipids production. R. opacus B4 consumed up to 96% of hexadecane (C16) impregnated in natural and regranulated cork sorbents after 48h incubation, producing 0.59±0.06g of triacylglycerol (TAG) g^-1 of C16 consumed with a TAG content of 0.60±0.06gg^-1 of cellular dry weight (CDW) and 0.54±0.05g TAG g^-1 of C16 consumed with a TAG content of 0.77±0.04gg^-1 (CDW), respectively. TAG was mainly composed by fatty acids of 16 and 18 carbon chains demonstrating the feasibility of using it as raw material for biodiesel production. In addition, the obtained lipid-rich biomass (whole cells) can be used for biomethane production, at a yield of 0.4L CH₄ g^-1 (CDW). The obtained results support a novel approach for management of oil-spill contaminated cork sorbents through its valorisation by producing bacterial lipids, which can be used as feedstocks for biofuels production.

Effects of citronella oil (Cymbopogon winterianus Jowitt ex Bor) on Spodoptera frugiperda (J. E. Smith) midgut and fat body

The armyworm, Spodoptera frugiperda, is the principal pest of corn in Brazil. Control is achieved primarily by synthetic insecticides, which cause problems for the agro-ecosystem. Alternative methods of control are under investigation and citronella (Cymbopogon winterianus) essential oil appears to be a promising agent. We investigated the effects of citronella oil using histological, histochemical and immunohistochemical methods. The midgut of larvae treated with citronella exhibited altered epithelium including cytoplasmic protrusions, columnar cell extrusion, pyknotic nuclei, and increased periodic acid-Schiff positive granules. Regenerative cells in the epithelium of the midgut increased in number, which facilitated subsequent regeneration of this tissue. After exposure to citronella, trophocytes, the principal cell type of the fat body, possessed enlarged vacuoles and mitotic bodies, and contained reduced amounts of glycogen, lipid, and protein. Citronella oil caused morphological changes of the midgut and reduction of stored resources in the fat body, which may adversely affect insect reproduction and survival.

Desolventizing of Jatropha curcas oil from azeotropes of solvents using ceramic membranes

The separation of Jatropha curcas oil from azeotropes of ethyl alcohol-n-hexane and isopropyl alcohol-n-hexane using ceramic membranes with different cutoffs (5, 10 and 20 kDa) is presented. The mass ratios of oil:azeotropes (O:S) studied were 1:3 for feeding pressures of 0.1, 0.2 and 0.3 MPa, and 1:1 for the feeding pressure of 0.1 MPa. Isopropyl alcohol was the best solvent for the membranes conditioning to permeate n-hexane (240 kg/m²h). In the separation of J. curcas oil and azeotropes of solvents, both membranes showed oil retention and total flux decreases with time. Overall, the lowest decrease in the retentions was reached in the 5 kDa membrane, while the lowest decrease in the total flux was reached in the 20 kDa. In the separation of oil and ethyl alcohol-n-hexane azeotrope, the best retention at 60 min of the process was equal to 17.3 wt% in the 20 kDa membrane at 0.3 MPa and O:S ratio equalled to 1:3. In this condition, the total permeate flux was 17.5 kg/m² h. Different retentions and permeabilities are provided when changing the O:S ratio, the feeding pressure and the molecular weight cutoff of membranes.

Sublethal Effects of Essential Oils From Eucalyptus staigeriana (Myrtales: Myrtaceae), Ocimum gratissimum (Lamiales: Laminaceae), and Foeniculum vulgare (Apiales: Apiaceae) on the Biology of Spodoptera frugiperda (Lepidoptera: Noctuidae)

Spodoptera frugiperda (Smith 1797) (Lepidoptera: Noctuidae) is a major pest of maize, Zea mays L. Its control is often achieved through repeated applications per season of insecticides, which may lead to adverse effects on the ecosystem. Thus, the study of alternative methods with less environmental impact has expanded to include the use of essential oils. These oils are products of the secondary metabolism in plants, and their insecticidal activity has been widely demonstrated in populations of many pest insects. This study evaluated the insecticidal activities of essential oils from Eucalyptus staigeriana, Ocimum gratissimum, and Foeniculum vulgare on Spodoptera frugiperda. Gas chromatography–mass spectrometry profiles and contact toxicity of these oils as well as their sublethal effects on larvae and reproductive parameters in adults were evaluated. All three oils had sublethal effects on S. frugiperda; however, the oil of O. gratissimum showed the best results at all doses tested. These essential oils may have promise for control of S. frugiperda.

Optimization of biogas production from Sargassum sp. using a design of experiments to assess the co-digestion with glycerol and waste frying oil

A design of experiments was adopted to assess the optimal conditions for methane production from the macroalgae Sargassum sp. co-digested with glycerol (Gly) and waste frying oil (WFO). Three variables were tested: % total solids of algae (%TSSargassumsp.), co-substrate concentration (gGly/WFOL(-1)), and co-substrate type (Gly or WFO). The biochemical methane potential (BMP) of Sargassum sp. was 181±1L CH4kg(-1) COD. The co-digestion with Gly and WFO increased the BMP by 56% and 46%, respectively. The methane production rate (k), showed similar behaviour as the BMP, increasing 38% and 19% with Gly and WFO, respectively. The higher BMP (283±18L CH4kg(-1) COD) and k (65.9±2.1L CH4kg(-1) CODd(-1)) was obtained in the assay with 0.5% TS and 3.0gGlyL(-1). Co-digestion with glycerol or WFO is a promising process to enhance the BMP from the macroalgae Sargassum sp.

Comparison between Oligoryzomys nigripes and O. flavescens by RAPD and genetic diversity in O. nigripes (Rodentia, Cricetidae)

The genus of Oligoryzomys includes species of small size, morphologically similar, which may impede taxonomic identification, mainly between O. flavescens (Waterhouse, 1837) and O. nigripes (Olfers, 1818). The main objective of this work was to investigate whether the RAPD markers are capable of genetically differentiating the specimens O. nigripes and O. flavescens, coming from Rio Grande do Sul (RS) and Santa Catarina (SC) states, and also to estimate the genetic variability among populations of O. nigripes, with the Uruguay River as a geographical barrier. For this purpose, samples were collected in fragments of forests situated in the North of RS, at FLONA (Floresta Nacional de Passo Fundo) and in fragments from SC, close to the Uruguay River. The karyotyping of two samples for each species was carried out and compared using the RAPD technique together with non- karyotyped individuals. Samples of O. nigripes presented 2n = 62; NA = 82, with submetacentric arms on the largest chromosomes, while samples of O. flavescens showed 2n = 64; NA = 66, with the largest chromosomes presenting acrocentric morphology, making such a result the main difference between the species. The analysis was able to detect two distinct groups, being the first one with karyotyped O. flavescens and the second with karyotyped O. nigripes. Identification afforded 211 loci, among them 181 (85.78%) polymorphic. The Jaccard similarity coefficient was in the range of 0.45 to 0.87. The UPGMA and Main Coordinate Analysis techniques demonstrated the existence of heterogeneous genetics among populations, but did not separate them completely in terms of geographical standards, and they are not influenced by the Uruguay River, which did not act as an efficient barrier.

Design of experiments to assess pre-treatment and co-digestion strategies that optimize biogas production from macroalgae Gracilaria vermiculophylla

A design of experiments was applied to evaluate different strategies to enhance the methane yield of macroalgae Gracilaria vermiculophylla. Biochemical Methane Potential (BMP) of G. vermiculophylla after physical pre-treatment (washing and maceration) reached 481±9 L CH4 kg(-1) VS, corresponding to a methane yield of 79±2%. No significant effects were achieved in the BMP after thermochemical pre-treatment, although the seaweeds solubilisation increased up to 44%. Co-digestion with glycerol or sewage sludge has proved to be effective for increasing the methane production. Addition of 2% glycerol (w:w) increased the BMP by 18%, achieving almost complete methanation of the substrate (96±3%). Co-digestion of seaweed and secondary sludge (15:85%, TS/TS) increased the BMP by 25% (605±4 L CH4 kg(-1) VS) compared to the seaweed individual digestion.

Bioactivity of Piper hispidinervum (Piperales: Piperaceae) and Syzygium aromaticum (Myrtales: Myrtaceae) oils, with or without formulated Bta on the biology and immunology of Spodoptera frugiperda (Lepidoptera: Noctuidae)

The combination of essential oils and Bacillus thuringiensis Berliner may represent an interesting control strategy. Thus, the study tested the following hypothesis: the combination of long pepper oil (Piper hispidinervum L.) and clove (Syzygium aromaticum L.) oils in two concentrations with Xentari WG (Bta) yields a more effective control of Spodoptera frugiperda (JE Smith) (Lepidoptera: Noctuidae) affecting biological and reproductive parameters and leading to changes in the levels of phenoloxidase and nitric oxide in the hemolymph of the pest. The results demonstrate that only long pepper oil, at the highest concentration with Xentari WG (Bta), promotes reduced larval survival. However, both oils with or without the insecticide interfere in the biology and humoral immunity of S.frugiperda. All treatments caused a decrease in the amount of eggs, except for the clove oil at both concentrations without Bta. Therefore, the use of these oils is a promising alternative for the integrated management of S. frugiperda; however, its association with Bta demonstrated no significant increase in their efficiency.

Modularity and evolutionary constraints in a baculovirus gene regulatory network

BACKGROUND

The structure of regulatory networks remains an open question in our understanding of complex biological systems. Interactions during complete viral life cycles present unique opportunities to understand how host-parasite network take shape and behave. The Anticarsia gemmatalis multiple nucleopolyhedrovirus (AgMNPV) is a large double-stranded DNA virus, whose genome may encode for 152 open reading frames (ORFs). Here we present the analysis of the ordered cascade of the AgMNPV gene expression.

RESULTS

We observed an earlier onset of the expression than previously reported for other baculoviruses, especially for genes involved in DNA replication. Most ORFs were expressed at higher levels in a more permissive host cell line. Genes with more than one copy in the genome had distinct expression profiles, which could indicate the acquisition of new functionalities. The transcription gene regulatory network (GRN) for 149 ORFs had a modular topology comprising five communities of highly interconnected nodes that separated key genes that are functionally related on different communities, possibly maximizing redundancy and GRN robustness by compartmentalization of important functions. Core conserved functions showed expression synchronicity, distinct GRN features and significantly less genetic diversity, consistent with evolutionary constraints imposed in key elements of biological systems. This reduced genetic diversity also had a positive correlation with the importance of the gene in our estimated GRN, supporting a relationship between phylogenetic data of baculovirus genes and network features inferred from expression data. We also observed that gene arrangement in overlapping transcripts was conserved among related baculoviruses, suggesting a principle of genome organization.

CONCLUSIONS

Albeit with a reduced number of nodes (149), the AgMNPV GRN had a topology and key characteristics similar to those observed in complex cellular organisms, which indicates that modularity may be a general feature of biological gene regulatory networks.

Morphological characterisation and agronomical parameters of different species of Salvia sp. (Lamiaceae)

The aim of this work is to assess the morphological characteristics and parameters of biomass production, such as fresh and dry matter weight (FMW and DMW, g/plant), yield of dry matter (YDM) in terms of ton/ha, essential oil content (EOC, mL/100 g) and yield of essential oils (YEO) expressed as L/ha of the following plants Salvia verbenaca, Salvia argentea, Salvia lavandulifolia, Salvia pratensis, Salvia sclarea, Salvia triloba and Salvia officinalis. Except for Salvia argentea (S2) all other species have adapted to the south Brazilian climate conditions, with morphological differences among the species evaluated. In terms of DMW and YDM, S. officinalis was found to be the most productive species with 445.83 g/plant and 11.14 ton/ha. The higher essential oil content and yield was observed for S. officinalis, affording 1.99 mL/100 g and 221.74 L/ha, respectively. Chemical characterisation of the essential oils obtained from hydrodistillation was performed through GC and GC/MSD analyses, which revealed for most of the species studied, α e β-thujone, camphor and 1,8-cineole as major compounds, apart from S. sclarea, for which linalool, linalyl acetate and α-terpineol were the major components.

Histological description of the midgut and the pyloric valve of Tropidacris collaris (Stoll, 1813) (Orthopetera: Romaleidae)

The present research describes the histology of the midgut, gastric caeca, and pyloric valve of Tropidacris collaris (Stoll, 1813), (Orthopetera: Romaleidae). We used light microscopy, staining (Gomori's trichrome and periodic acid-Schiff (PAS)), and a routine histological analysis method (hematoxilin-eosin). The insects were obtained from, and also bred in, the Laboratory of Entomology, Department of Biology, of the Rural Federal University of Pernambuco (UFRPE). The collected material was fixed in alcoholic Boüin and embedded in paraplast. The results demonstrated that the midgut wall is composed of an inner epithelial layer and two outer layers of striate muscles: one internal (circular) and the other external (longitudinal), with connective tissue between the muscle fibers. The epithelium is single-layered, with two cell types: regenerative and elongated columnar. The gastric caeca presents muscle layers similar to those of the midgut. Simple columnar epithelium lines the gastric caeca, which presents villi and projects towards the lumen. The pyloric valve is of striate muscle tissue, covered by a single epithelial-cell layer.

Hepatocyte metaplasia in experimental chagasic pancreatitis: preliminary report

Beginning the study of chronic pathologic changes in pancreas of hamsters experimentally infected with Trypanosoma cruzi Vic strain, hepatocyte metaplasia was observed in one animal from infected group. This is the first report of oncocytes in Chagas' disease, which could be due to aberrant regenerative response to pancreas inflammatory process.

Evaluation of residual levels of benomyl, methyl parathion, diuron, and vamidothion in pineapple pulp and bagasse (Smooth cayenne)

The objective of this research was to study the residual levels of benomyl, methyl parathion, diuron, and vamidothion in pineapple bagasse and pulp. Benomyl (benlate), methyl parathion (Folidol 600), diuron (Krovar), and Vamidothion (Kilval 300) were applied pre-harvest to pineapples (smooth cayenne). After harvesting, the fruits were washed (100 ppm sodium hypochlorite) and the pulp was separated from the sub-products (peel, core, tops, and tails). The pulp was not submitted to any heat treatment. The sub-products and the juice expressed from them, were submitted to a blanching process (95 degrees C for 1 min). After separating the juice, the bagasse and pulp were analyzed for residues of diuron and benomyl by high performance liquid chromatography, and for residues of vamidothion and methyl parathion by gas chromatography using a TSD detector. No residues of benomyl, diuron, vamidothion, or methyl parathion were detected in the pulp within the quantification limits of the methods (0.1 mg/kg, 0.1 mg/kg, 0.005 mg/kg, and 0.005 mg/kg, respectively). Only methyl parathion (0.052 mg/kg) and vamidothion (0.021 mg/kg) were detected in the bagasse. The presence of these residues in the bagasse was probably due to the action of the wax found in the peel, which prevented the methyl parathion and vamidothion from dissolving in the juice. According to these results, the pulp was fit for human consumption, as far as pesticide residues were concerned, and the bagasse was fit for animal feed and similar applications, because the residual levels found were below the limits established for these compounds.