Ovarian development and analysis of mating effects on ovary maturation of Diaphorina citri Kuwayama (Hemiptera: Psyllidae)

As many other insects with a restricted diet, the citrus psyllid Diaphorina citri Kuwayama, which vector the causing agent of the Huanglongbing, the bacteria Candidatus Liberibacter spp., is intimately associated with symbiotic microorganisms. These mutualist symbionts play a key role on their host nutritional ecology, and are vertically transmitted to the progeny. However, despite the role symbionts play on host development and reproduction, and the growing opportunities of exploitation of the association insect-symbiont to control insect vectored-pathogens, there are very few studies on the host reproductive biology and on the symbiont transovarial transmission. Therefore, we aimed at analyzing the ovary development during D. citri adulthood, and at verifying for the mating requirement as a trigger to initiate ovary development. Newly-emerged D. citri females were grouped as virgin or mated and ovary development was observed during adulthood. Newly-emerged females have immature ovaries, and ovaries remain without any mature eggs until females mate. Once female mates, the vitellogenesis synthesis and uptake are estimulated, and oocytes are quickly developed. Oocytes maturation in ovarioles is metachronic, with only one oocyte developing at a time in each oogenic cycle. Morphological observations of the reproductive system including the ovaries and spermatheca, after the first cluster of eggs is laid, indicated D. citri is polyandrous, and may require multiple mating to develop additional oogenic maturation cycles.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Neural Bases of Cognitive Impairments in Post-Traumatic Stress Disorders : A Mini-Review of Functional Magnetic Resonance Imaging Findings

Introduction: Post-Traumatic Stress Disorder (PTSD) is often associated with impairments in emotional and cognitive domains. Contrarily to the emotional sphere, neural basis underpinnings to cognitive impairments are still not well known. Methods: We performed a bibliographic search on PUBMED of all the studies investigating the cognitive impairments in PTSD individuals. We considered only studies that applied cognitive tasks using a functional Magnetic Resonance Imaging technique. The inclusion criteria were met by nine studies. Results: Overall, PTSD individuals reported significant impairments in the dorsolateral prefrontal cortex, anterior cingulate cortex, inferior frontal gyrus, insula, inferior temporal cortex, supplement motor area, and Default Mode Network (DMN). Moreover, abnormal activity was reported in subcortical structures (e.g. hippocampus, amygdala, thalamus) and in the cerebellum. Limitations: Cognitive functioning was assessed using different cognitive tasks. Potential confounding factors such as age, sex, symptoms intensity, and comorbidities might have influenced the results. Conclusion: So far, the evidence reported that PTSD is characterized by cognitive impairments in several domains, such as attention, memory and autonomic arousal, which may be due to selective dysfunctions in brain regions that are part of cortical networks, the limbic system and DMN. However, further studies are needed in order to better assess the role of cognitive impairments in PTSD and to develop more targeted therapeutic approaches

A high-throughput, straightforward procedure for biomonitoring organomercury species in human hair

Mercury is a pervasive and concerning pollutant due to its toxicity, mobility, and tendency to biomagnify in aquatic and terrestrial ecosystems. Speciation analysis is crucial to assess exposure and risks associated with mercury, as different mercury species exhibit varying properties and toxicities. This study aimed at developing a selective detection method for organic mercury species in a non-invasive biomonitoring matrix like human hair. The method is based on frontal chromatography (FC) in combination with inductively coupled plasma mass spectrometry (ICP-MS), using a low pressure, homemade, anion exchange column inserted in a standard ICP-MS introduction system, without requiring high-performance liquid chromatography (HPLC) hyphenation. In addition to the extreme simplification and cost reduction of the chromatographic equipment, the proposed protocol involves a fast, streamlined and fully integrated sample preparation process (in contrast to existing methods): the optimized procedure features a 15-min ultrasonic assisted extraction procedure and 5 min analysis time. Consequently, up to 100 samples could be analyzed daily, making the method highly productive and suitable for large-scale screening programs in public and environmental health. Moreover, the optimized procedure enables a limit of detection (LOD) of 5.5 μg/kg for a 10 mg hair microsample. All these features undeniably demonstrate a significant advancement in routine biomonitoring practices. To provide additional evidence, the method was applied to forty-nine human hair samples from individuals with varying dietary habits successfully finding a clear correlation between methylmercury levels (ranging from 0.02 to 3.2 mg/kg) in hair and fish consumption, in line with previous literature data

n-3 AGPICL en la reversión de la esteatosis hepática: el papel de la ACOX y CAT

The aim of this study was to investigate the roles of the Acyl co-enzyme A oxidase (ACOX), carnitine acyl transferase I (CAT-1) and activating protein 1 (AP-1) in the reversal of hepatic steatosis with dietary change and n-3 long chain polyunsaturated fatty acid (n-3 LCPUFA) supplementation. Male C57BL/6J mice were given either a control diet (CD) or a high fat diet (HFD) for 12 weeks, and then continued with the CD or CD plus n-3 LCPUFA for eight weeks. After this period, body and adipose visceral tissue weight were analyzed and liver samples were taken to measure ACOX, CAT-1 and c-jun levels. The dietary change from HFD to a norm caloric diet plus n-3 LCPUFA supplementation significantly reduced liver steatosis and adipose tissue: body weight ratio, along with an increase in the hepatic ACOX and CAT-1 levels and normalization of AP-1 expression that could favor the fatty acid beta-oxidation over lipogenesis and regulate inflammation. These results provide new data on the enzymatic metabolism underlying dietary change to a norm caloric diet plus n-3 LCPUFA supplementation.El objetivo de este estudio fue investigar el rol de las enzimas Acil coenzima A oxidasa (ACOX) y Acil carnitina transferasa 1 (CAT-1), además del factor de transcripción, Proteína activadora 1 (AP-1) en la reversión de la esteatosis hepática mediante cambio de dieta más suplementación con Ácidos grasos poliinsaturados de cadena larga omega tres (AGPICL n-3). Ratones macho de la cepa C57BL/6J fueron alimentados con dieta control (DC) o alta en grasas (DAG) durante 12 semanas, luego continuaron con DC con o sin suplementación de AGPICL n-3 durante 8 semanas. Después de este período, se analizó el peso corporal y del tejido adiposo visceral; en las muestras hepáticas se evaluaron los niveles de ACOX, CAT-1 y AP-1. El cambio a dieta control más suplementación con AGPICL n-3 reduce significativamente la esteatosis hepática y la relación tejido adiposo/peso corporal, acompañado de un incremento en los niveles hepáticos de ACOX y CAT-1 y normalización de la expresión de AP-1; regulando la inflamación y favoreciendo la beta oxidación sobre la lipogénesis. Estos resultados proveen nuevos datos sobre el metabolismo enzimático cuando se realiza cambio a dieta control más suplementación con AGPICL n-3

How to clean and safely remove HF from acid digestion solutions for ultra-trace analysis: a microwave-assisted vessel-inside-vessel protocol

The complete dissolution of silicate-containing materials, often necessary for elemental determination, is generally performed by microwave-assisted digestion involving the forced use of hydrofluoric acid (HF). Although highly efficient in dissolving silicates, this acid exhibits many detrimental effects (e.g., formation of precipitates, corrosiveness to glassware) that make its removal after digestion essential. The displacement of HF is normally achieved by evaporation in open-vessel systems: atmospheric contamination or loss of analytes can occur when fuming-off HF owing to the non-ultraclean conditions necessarily adopted for safety reasons. This aspect strongly hinders determination at the ultra-trace level. To overcome this issue, we propose a clean and safe microwaveassisted procedure to induce the evaporative migration of HF inside a sealed \u201cvessel-inside-vessel\u201d system: up to 99.9% of HF can be removed by performing two additional microwave cycles after sample dissolution. HF migrates from the digestion solution to a scavenger (ultrapure H2O) via a simple physical mechanism, and then, it can be safely dismissed/recycled. The procedure was validated by a soil reference material (NIST 2710), and no external or cross-contamination was observed for the 27 trace elements studied. The results demonstrate the suitability of this protocol for ultra-trace analysis when the utilization of HF is mandatory

Exploring the Adsorption of Pb on Microalgae-Derived Biochar: A Versatile Material for Environmental Remediation and Electroanalytical Applications

Biochar, a carbon material obtained by pyrolysis of biomasses, is increasingly applied in environmental remediation and sensing thanks to its functional properties, cost-effectiveness and eco-friendliness. The adsorption capacity of biochar, strictly dependent on its specific surface area, heteroatom doping and surface functional groups, is crucial for these applications. Here, biochar produced at low temperature (350◦ C) from a marine microalga (Nannochloropsis sp.) is proposed as an efficient adsorbent of lead (II) ions in aqueous solution; this production strategy promotes the natural self-doping of biochar without requiring harsh conditions. The kinetics and thermodynamics of the adsorption process, as well as the effect of pH, ionic strength and dissolved organic matter on the adsorption efficiency were systematically assessed. The microalgae-derived biochar shows superior adsorption performances compared to a nutshell-derived one (used as a reference of lignocellulosic feedstocks) under all the tested conditions. The microalgae-derived biochar was finally used to decorate screen-printed carbon electrodes to improve the electroanalytical performances towards the voltammetric detection of lead (II) ions. A two-fold increase in sensitivity was obtained compared to the unmodified electrode thanks to the enhanced electron transfer and adsorption properties provided by biochar. These results highlight the potentialities of microalgae-derived biochar for environmental and sensing applications

The voltammetric behaviour of lead at a hand drawn pencil electrode and its trace determination in water by stripping voltammetry

This is the first reported the proof of concept application of pencil drawn electrodes (PDEs) for anodic stripping voltammetric determination of Pb2+ or any metal ion. PDEs offer advantages of economics, simplicity and rapid fabrication, affording a green alternative for the development of new devices. Cyclic voltammetric investigations of Pb2+ at these electrodes in 0.30 M acetic acid were characterised by a cathodic reduction peak on the initial negative scan resulting from the reduction of Pb2+ ions to Pb0. Anodic peaks obtained on the return positive scan showed that Pb had been deposited as a thin film on the PDE surface. The addition of Cl ions to this electrolyte improved the voltammetric behaviour and a supporting electrolyte of 0.30 M acetic acid containing 0.25 M KCl was found to be optimum. Investigations were made into the possibility of determining trace levels of Pb2+ by differential pulse anodic stripping voltammetry. The effect of accumulation potential and time were investigated and optimised. Three anodic stripping peaks were recorded resulting from the heterogeneous nature of the electrode surface. Using an accumulation potential of 1.1 V and an accumulation time of 200 s a bimodal calibration curve was recorded, with linear ranges between 80 to 330 ng/mL and 330 to 915 ng/mL. The theoretical detection limit (3σ) was calculated as 9.5 ng/mL. Pb2+ determinations on a drainage water sample gave a mean recovery of 100.9 % (%CV= 5.7 %) at a concentration of 166.1 ng/mL indicating the method holds promise for the determination of Pb2+ in such samples

Advancing on the understanding of the genome, gene expression, and potential for biotechnological exploitation of the polydnavirus associated with Cotesia flavipes.

Cotesia flavipes (Hymenoptera, Braconidae) in an efficient larval parasitoid of the sugarcane borer Diatraea saccharalis (Lepidoptera, Crambidae). C. flavipes was introduced and is successfully used in applied biological control programs over extensive areas of sugarcane production in Brazil. The successful exploitation of host larvae by Cotesia flavipes is related to a plethora of regulatory molecules this wasp injects into the host or that is produced by parasitoid-derived tissues and associated symbiotic virus (Polydnavirus ? PDV). PDVs produce several proteins that allow host colonization by immature parasitoids, as they affect the host immune system, regulate host metabolism and growth. PDV-derived proteins are an interesting source of molecules that could be used in developing genetically-modified plants suitable for sustainable pest management. In order to determine the diversity of proteins the PDV associated with Cotesia flavipes (CfPDV) and their production during parasitoid development, we obtained high throughput sequencing data and partially sequenced, annotated and compared the PDV genome of C. flavipes to other related PDVs. A set of PDV genes was selected and their expression in parasitized host larvae was assessed. In order to evaluate the potential for biotechnological exploitation of such proteins in pest control, candidate genes were selected and used for plant transformation to allow testing the effects of CfPDV proteins on non-preferred host insects