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1.
PLoS One ; 19(1): e0294122, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38261561

RESUMO

It is not possible to systematically screen the environment for rabies virus (RABV) using current approaches. We sought to determine under what conditions RABV is detectable from feces and other accessible samples from infected wildlife to broaden the number of biological samples that could be used to test for RABV. We employed a recently-developed quantitative RT-PCR assay called the "LN34 panlyssavirus real-time RT-PCR assay", which is highly sensitive and specific for all variants of RABV. We harvested and tested brain tissue, fecal, and/or mouth swab samples from 25 confirmed RABV positive bats of six species. To determine if rabies RNA lasts in feces sufficiently long post-defecation to use it as a surveillance tool, we tested fecal samples from 10 bats at the time of sample collection and after 24 hours of exposure to ambient conditions, with an additional test on six bats out to 72 hours. To assess whether we could pool fecal pellets and still detect a positive, we generated dilutions of known positives at 1:1, 1:10, 1:50, and 1:200. For six individuals for which matched brain, mouth swab, and fecal samples were tested, results were positive for 100%, 67%, and 67%, respectively. For the first time test to 24 hours, 63% of feces that were positive at time 0 were still positive after 24 hours, and 50% of samples at 72 hours were positive across all three replicates. Pooling tests revealed that fecal positives were detected at 1:10 dilution, but not at 1:50 or 1:200. Our preliminary results suggest that fecal samples hold promise for a rapid and non-invasive environmental screening system.


Assuntos
Líquidos Corporais , Quirópteros , Lepidópteros , Vírus da Raiva , Raiva , Humanos , Animais , Fezes
2.
Hepatology ; 79(3): 538-550, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-37676683

RESUMO

BACKGROUND AND AIMS: The International Autoimmune Hepatitis Group retrospective registry (IAIHG-RR) is a web-based platform with subjects enrolled with a clinical diagnosis of autoimmune hepatitis (AIH). As prognostic factor studies with enough power are scarce, this study aimed to ascertain data quality and identify prognostic factors in the IAIHG-RR cohort. METHODS: This retrospective, observational, multicenter study included all patients with a clinical diagnosis of AIH from the IAIHG-RR. The quality assessment consisted of external validation of completeness and consistency for 29 predefined variables. Cox regression was used to identify risk factors for liver-related death and liver transplantation (LT). RESULTS: This analysis included 2559 patients across 7 countries. In 1700 patients, follow-up was available, with a completeness of individual data of 90% (range: 30-100). During a median follow-up period of 10 (range: 0-49) years, there were 229 deaths, of which 116 were liver-related, and 143 patients underwent LT. Non-White ethnicity (HR 4.1 95% CI: 2.3-7.1), cirrhosis (HR 3.5 95% CI: 2.3-5.5), variant syndrome with primary sclerosing cholangitis (PSC) (HR 3.1 95% CI: 1.6-6.2), and lack of complete biochemical response within 6 months (HR 5.7 95% CI: 3.4-9.6) were independent prognostic factors. CONCLUSIONS: The IAIHG-RR represents the world's largest AIH cohort with moderate-to-good data quality and a relevant number of liver-related events. The registry is a suitable platform for patient selection in future studies. Lack of complete biochemical response to treatment, non-White ethnicity, cirrhosis, and PSC-AIH were associated with liver-related death and LT.


Assuntos
Colangite Esclerosante , Hepatite Autoimune , Transplante de Fígado , Humanos , Hepatite Autoimune/diagnóstico , Estudos Retrospectivos , Cirrose Hepática/complicações , Colangite Esclerosante/complicações
3.
J Hepatol ; 80(1): 53-61, 2024 01.
Artigo em Inglês | MEDLINE | ID: mdl-37802188

RESUMO

BACKGROUND AND AIMS: Autoimmune hepatitis (AIH) is a rare chronic liver disease of unknown aetiology; the risk of hepatocellular carcinoma (HCC) remains unclear and risk factors are not well-defined. We aimed to investigate the risk of HCC across a multicentre AIH cohort and to identify predictive factors. METHODS: We performed a retrospective, observational, multicentric study of patients included in the International Autoimmune Hepatitis Group Retrospective Registry. The assessed clinical outcomes were HCC development, liver transplantation, and death. Fine and Gray regression analysis stratified by centre was applied to determine the effects of individual covariates; the cumulative incidence of HCC was estimated using the competing risk method with death as a competing risk. RESULTS: A total of 1,428 patients diagnosed with AIH from 1980 to 2020 from 22 eligible centres across Europe and Canada were included, with a median follow-up of 11.1 years (interquartile range 5.2-15.9). Two hundred and ninety-three (20.5%) patients had cirrhosis at diagnosis. During follow-up, 24 patients developed HCC (1.7%), an incidence rate of 1.44 cases/1,000 patient-years; the cumulative incidence of HCC increased over time (0.6% at 5 years, 0.9% at 10 years, 2.7% at 20 years, and 6.6% at 30 years of follow-up). Patients who developed cirrhosis during follow-up had a significantly higher incidence of HCC. The cumulative incidence of HCC was 2.6%, 4.6%, 5.6% and 6.6% at 5, 10, 15, and 20 years after the development of cirrhosis, respectively. Obesity (hazard ratio [HR] 2.94, p = 0.04), cirrhosis (HR 3.17, p = 0.01), and AIH/PSC variant syndrome (HR 5.18, p = 0.007) at baseline were independent risk factors for HCC development. CONCLUSIONS: HCC incidence in AIH is low even after cirrhosis development and is associated with risk factors including obesity, cirrhosis, and AIH/PSC variant syndrome. IMPACT AND IMPLICATIONS: The risk of developing hepatocellular carcinoma (HCC) in individuals with autoimmune hepatitis (AIH) seems to be lower than for other aetiologies of chronic liver disease. Yet, solid data for this specific patient group remain elusive, given that most of the existing evidence comes from small, single-centre studies. In our study, we found that HCC incidence in patients with AIH is low even after the onset of cirrhosis. Additionally, factors such as advanced age, obesity, cirrhosis, alcohol consumption, and the presence of the AIH/PSC variant syndrome at the time of AIH diagnosis are linked to a higher risk of HCC. Based on these findings, there seems to be merit in adopting a specialized HCC monitoring programme for patients with AIH based on their individual risk factors.


Assuntos
Carcinoma Hepatocelular , Hepatite Autoimune , Neoplasias Hepáticas , Humanos , Carcinoma Hepatocelular/epidemiologia , Carcinoma Hepatocelular/etiologia , Carcinoma Hepatocelular/diagnóstico , Hepatite Autoimune/complicações , Hepatite Autoimune/epidemiologia , Hepatite Autoimune/diagnóstico , Incidência , Cirrose Hepática/complicações , Cirrose Hepática/epidemiologia , Neoplasias Hepáticas/epidemiologia , Neoplasias Hepáticas/etiologia , Neoplasias Hepáticas/diagnóstico , Obesidade/complicações , Estudos Retrospectivos , Fatores de Risco
4.
Ecol Evol ; 13(9): e10461, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37693939

RESUMO

Lizard diets are highly diverse and have contributed to the diversification, biogeographical distributions, and evolution of novel traits across this global radiation. Many parts of a lizard's ecology-including habitat preferences, foraging modes, predation risks, interspecific competition, and thermal constraints, among others-interact to shape diets, and dietary niche partitioning simultaneously contributes to co-occurrence within communities. We used DNA metabarcoding of fecal samples to identify prey items in the diets of three sympatric Sceloporus lizards in the Madrean Sky Islands of Arizona, USA. We found evidence for dietary niche partitioning between interacting species concomitant with their respective ecologies. We also compared diet composition between populations to understand how conserved or plastic species' diets are between different environments. Our findings suggest that habitat generalists are also diet generalists in this system, while the same may be true for specialists. The identification of prey items to much lower taxonomic levels than previously documented further reveals hidden diversity in the diets of these species and underscores the utility of metabarcoding for understanding the full complexity of lizard diets.

5.
PLoS One ; 18(6): e0287536, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37352304

RESUMO

Bats are prodigious consumers of agricultural and forest pests, and are, therefore, a natural asset for agricultural productivity, suppressing populations of such pests. This study provides baseline information of diet of 143 bats belonging to eight insectivorous bat species from agricultural areas of Rwanda while evaluating the effectiveness of bats as pest suppressors. Using DNA metabarcoding to analyze bat fecal pellets, 85 different insect species were detected, with 60% (n = 65), 64% (n = 11) and 78% (n = 9) found to be agricultural pests from eastern, northern and western regions, respectively. Given the high percentages of agricultural pests detected, we submit that Rwandan insectivorous bats have the capacity for biocontrol of agricultural pests. Rwandan bat populations should be protected and promoted since they may foster higher crop yields and sustainable livelihoods.


Assuntos
Quirópteros , Mariposas , Animais , Ecossistema , Ruanda , Florestas
6.
Rev. méd. Chile ; 151(2): 197-205, feb. 2023. ilus, tab
Artigo em Espanhol | LILACS | ID: biblio-1522083

RESUMO

BACKGROUND: Different modalities of quarantines were one of the main measures implemented worldwide to avoid the spread of SARS-CoV2 virus. AIM: To analyze and compare retrospectively the implementation of the Step- to-Step plan devised by the Chilean Ministry of Health during the pandemic. To propose a decision-making path based on an artificial intelligence fuzzy system to determine confinements in specific territories. MATERIAL AND METHODS: The Step-to-Step Plan threshold values such hospital network capacity, epidemic spreading, testing and contact tracing capability were modeled using fuzzy numbers and fuzzy rule-based systems. RESULTS: Ministry of Health's decision-making opportuneness were unrelated with the Step-to-Step Plan indicators for deconfinement. Such disagreements undermined epidemiological indicators. CONCLUSIONS: Using an artificial intelligence system could improve decision-making transparency, emergency governance, and risk communication to the population.


Assuntos
Humanos , Inteligência Artificial , Quarentena , RNA Viral , Estudos Retrospectivos , Lógica Fuzzy
7.
Rev Med Chil ; 151(2): 197-205, 2023 Feb.
Artigo em Espanhol | MEDLINE | ID: mdl-38293855

RESUMO

BACKGROUND: Different modalities of quarantines were one of the main measures implemented worldwide to avoid the spread of SARS-CoV2 virus. AIM: To analyze and compare retrospectively the implementation of the Step- to-Step plan devised by the Chilean Ministry of Health during the pandemic. To propose a decision-making path based on an artificial intelligence fuzzy system to determine confinements in specific territories. MATERIAL AND METHODS: The Step-to-Step Plan threshold values such hospital network capacity, epidemic spreading, testing and contact tracing capability were modeled using fuzzy numbers and fuzzy rule-based systems. RESULTS: Ministry of Health's decision-making opportuneness were unrelated with the Step-to-Step Plan indicators for deconfinement. Such disagreements undermined epidemiological indicators. CONCLUSIONS: Using an artificial intelligence system could improve decision-making transparency, emergency governance, and risk communication to the population.


Assuntos
Inteligência Artificial , Quarentena , Humanos , RNA Viral , Estudos Retrospectivos , Lógica Fuzzy
8.
Animals (Basel) ; 12(22)2022 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-36428303

RESUMO

Leptonycteris nivalis (the Mexican long-nosed bat) is an endangered nectar-feeding bat species that follows "nectar corridors" as it migrates from Mexico to the southwestern United States. Locating these nectar corridors is key to their conservation and may be possible using environmental DNA (eDNA) from these bats. Hence, we developed and tested DNA metabarcoding and qPCR eDNA assays to determine whether L. nivalis could be detected by sampling the agave flowers on which it feeds. We sampled plants with known bat visitations in the Sierra Madre Oriental in Laguna de Sanchez (LS), Nuevo León, Mexico, and in the Chisos Mountains in Big Bend National Park, TX, USA (CB). A total of 13 samples included both swabs of agave umbels and cuttings of individual flowers. DNA metabarcoding was performed as a PCR multiplex that targeted bats (SFF-COI), arthropods (ANML-COI), and plants (ITS2 and rbcL). We targeted arthropods and plants in parallel with bats because future metabarcoding studies may wish to examine all the pollinators and plants within the nectar corridor. We developed and tested the sensitivity and specificity of two qPCR assays. We found that both DNA metabarcoding and qPCR were highly successful at detecting L. nivalis (11 of 13 for DNA metabarcoding and 12 of 13 for qPCR). Swabs and flower cuttings and both qPCR assays detected the species over four replicates. We suggest that L. nivalis leaves substantial DNA behind as it forages for nectar. We also suggest that future studies examine the time since sampling to determine its effect on detection success. The DNA metabarcoding multiplex will be useful for parallel questions regarding pollination ecology, while, with further testing, the qPCR assays will be effective for large-scale sampling for the detection of migration corridors and foraging areas. This work may be relevant to other nectar-feeding bat species, which can likely be detected with similar methodologies.

9.
Turk J Urol ; 48(5): 331-338, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-36197140

RESUMO

OBJECTIVE: To evaluate the impact on continence rate during 1-year follow-up of a preservation technique that included nonligation of the dorsal vascular complex and sparing of the puboprostatic ligaments and the endopelvic fascia during laparoscopic radical prostatectomy. MATERIAL AND METHODS: Information from 30 patients who underwent the preservation technique was prospectively collected and compared with data from 60 patients who underwent the nonpreservation traditional technique. A single surgeon performed all procedures. RESULTS: Demographic and preoperative characteristics were similar. The mean patient age was 59 years in both groups. All patients were stage cT1c or cT2. Operative time was significantly lower in the preservation technique group (229.6 vs. 262.7 minutes, P < .001). There were no significant differences in intraoperative bleeding, discharge hemoglobin level, blood transfusion rate, length of hospitalization, and drop in the hemoglobin level. The probability of continence recovery was significantly higher in the preservation technique group than in the traditional technique group (hazard ratio = 0.50, 95% CI = 0.31-0.81). The continence rate (0 pads/day) for the preservation technique group versus the traditional technique group at 1, 3, 6, and 12 months was, respectively, 53.3% versus 30% (P = .031), 90% versus 45% (P < .001), 90% versus 63.3% (P = .008), and 96.6% versus 78.3% (P = .024). There were no significant differences between the groups regarding potency and oncologic outcomes. CONCLUSION: Nonligation of the dorsal vascular complex and preservation of the puboprostatic ligaments and the endopelvic fascia improved urinary continence compared with the traditional nonpreservation technique, with no impact in terms of bleeding and oncologic outcomes.

10.
Expert Opin Drug Metab Toxicol ; 18(9): 555-573, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-36107152

RESUMO

INTRODUCTION: Idiosyncratic drug-induced liver injury (iDILI) is a challenging and unpredictable multifactorial condition. At present, validated preclinical models for the prediction of the hepatotoxic potential of a given drug are scarce. AREAS COVERED: This review intends to sum up the current knowledge about in vitro (including hepatocyte 2D cultures, cocultures with non-parenchymal cells, 3D configurations and non-typical closer to reality in vitro models), in vivo (covering models for immunological and oxidative stress features, humanized mouse-based and non-rodent models) and in silico approaches for iDILI modeling, highlighting the recent advances in each topic. EXPERT OPINION: The future strategy for iDILI modeling should be patient-centered. Future animal and cell-based models, with more predictive value, will be easier to design by using a more translational approach based on mechanisms demonstrated in humans. Genetic and epigenetic information gathered from iDILI patients, together with data from in vitro and in vivo studies, could be used to develop sophisticated predictive in silico models to find compounds with iDILI potential. Collecting genetic, metabolic, and biomarker data from patient cohorts might be another option to create a 'fingerprint' characteristic of people at risk, allowing for the development of new, mechanistic strategies to enhance iDILI in vitro evaluation.


Assuntos
Doença Hepática Induzida por Substâncias e Drogas , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos , Animais , Biomarcadores/metabolismo , Doença Hepática Induzida por Substâncias e Drogas/etiologia , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos/metabolismo , Hepatócitos , Humanos , Fígado/metabolismo , Camundongos
11.
Biology (Basel) ; 10(2)2021 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-33540586

RESUMO

Mass cytometry (CyTOF) is a relatively novel technique for the multiparametric analysis of single-cell features with an increasing central role in cell biology, immunology, pharmacology, and biomedicine. This technique mixes the fundamentals of flow cytometry with mass spectrometry and is mainly used for in-depth studies of the immune system and diseases with a significant immune load, such as cancer, autoimmune diseases, and viral diseases like HIV or the recently emerged COVID-19, produced by the SARS-CoV-2 coronavirus. The objective of this study was to provide a useful insight into the evolution of the mass cytometry research field, revealing the knowledge structure (conceptual and social) and authors, countries, sources, documents, and organizations that have made the most significant contribution to its development. We retrieved 937 articles from the Web of Science (2010-2019), analysed 71 Highly Cited Papers (HCP) through the H-Classics methodology and computed the data by using Bibliometrix R package. HCP sources corresponded to high-impact journals, such as Nature Biotechnology and Cell, and its production was concentrated in the US, and specifically Stanford University, affiliation of the most relevant authors in the field. HCPs analysis confirmed great interest in the study of the immune system and complex data processing in the mass cytometry research field.

12.
Acta Pharm Sin B ; 11(12): 3685-3726, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35024301

RESUMO

Idiosyncratic drug-induced liver injury (iDILI) encompasses the unexpected harms that prescription and non-prescription drugs, herbal and dietary supplements can cause to the liver. iDILI remains a major public health problem and a major cause of drug attrition. Given the lack of biomarkers for iDILI prediction, diagnosis and prognosis, searching new models to predict and study mechanisms of iDILI is necessary. One of the major limitations of iDILI preclinical assessment has been the lack of correlation between the markers of hepatotoxicity in animal toxicological studies and clinically significant iDILI. Thus, major advances in the understanding of iDILI susceptibility and pathogenesis have come from the study of well-phenotyped iDILI patients. However, there are many gaps for explaining all the complexity of iDILI susceptibility and mechanisms. Therefore, there is a need to optimize preclinical human in vitro models to reduce the risk of iDILI during drug development. Here, the current experimental models and the future directions in iDILI modelling are thoroughly discussed, focusing on the human cellular models available to study the pathophysiological mechanisms of the disease and the most used in vivo animal iDILI models. We also comment about in silico approaches and the increasing relevance of patient-derived cellular models.

13.
PLoS One ; 14(11): e0224969, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31725795

RESUMO

DNA metabarcoding assays are powerful tools for delving into the DNA in wildlife feces, giving unprecedented ability to detect species, understand natural history, and identify pathogens for a range of applications in management, conservation, and research. Next-generation sequencing technology is developing rapidly, which makes it especially important that predictability and reproducibility of DNA metabarcoding assays are explored together with the post-depositional ecology of the target taxon's fecal DNA. Here, we defined the constraints of an assay called 'Species from Feces' used by government agencies, research groups, and non-governmental organizations to identify bat species from guano. We tested assay sensitivity by examining how time and humidity affect the ability to recover and successfully sequence DNA in guano, assessing whether a fecal pellet from a rare bat species could be detected in a background of feces from other bat species, and evaluating the efficacy of Species from Feces as a survey tool for bat roosts in temperate and tropical areas. We found that the assay performs well with feces over two years old in dry, cool environments, and fails by 12 months at 100% relative humidity. We also found that it reliably identifies rare DNA, has great utility for surveying roosts in temperate and tropical regions, and detects more bat species than do visual surveys. We attribute the success of Species from Feces to characteristics of the assay paired with application in taxa that are particularly well-suited for fecal DNA survival. In a time of rapid evolution of DNA metabarcoding approaches and their use with feces, this study illustrates the strengths and limitations of applied assays.


Assuntos
Quirópteros/genética , Fezes/química , Testes Genéticos/métodos , Animais , Arqueologia , Umidade , Mineração , Reprodutibilidade dos Testes , Sudoeste dos Estados Unidos , Especificidade da Espécie , Fatores de Tempo
14.
Pest Manag Sci ; 74(12): 2817-2821, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29766638

RESUMO

BACKGROUND: The Spodoptera cosmioides (Walker, 1858) population has increased in Bacillus thuringiensis Berliner (Bt) soybean crops in Argentina. As there are no registered products for its control, the recommended insecticides for S. frugiperda are used. The aim of this study was therefore to determine the lethal concentration (LC) of chlorantraniliprole and its sublethal effects on the biological and reproductive functions of S. cosmioides, an emerging soybean pest in Argentina. RESULTS: An ingestion toxicity bioassay showed that chlorantraniliprole was active against larvae of the second instar, and after 48 h of exposure LC50 was 0.054 µg mL-1 H2 O. In the study of sublethal effect, chlorantraniliprole induced changes in the life cycle of exposed S. cosmioides, which required more time to complete all stages of development (larval, pupal and adult stages). Pupal weight was also higher in larvae exposed to sublethal concentrations of chlorantraniliprole. Adult fecundity was decreased: the number of eggs laid by each adult female moth, as compared with control females, was two (LC15 ) and eight (LC30 ) times lower. CONCLUSION: These results indicate that chlorantraniliprole has toxicity against S. cosmioides larvae. Sublethal effects on the biological and reproductive performance of this species can help optimize integrated pest management programs. © 2018 Society of Chemical Industry.


Assuntos
Inseticidas , Spodoptera , ortoaminobenzoatos , Animais , Relação Dose-Resposta a Droga , Umidade , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Larva/fisiologia , Estágios do Ciclo de Vida/efeitos dos fármacos , Reprodução/efeitos dos fármacos , Spodoptera/fisiologia , Temperatura
15.
PLoS One ; 11(9): e0162342, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27654850

RESUMO

Bat guano is a relatively untapped reservoir of information, having great utility as a DNA source because it is often available at roosts even when bats are not and is an easy type of sample to collect from a difficult-to-study mammalian order. Recent advances from microbial community studies in primer design, sequencing, and analysis enable fast, accurate, and cost-effective species identification. Here, we borrow from this discipline to develop an order-wide DNA mini-barcode assay (Species from Feces) based on a segment of the mitochondrial gene cytochrome c oxidase I (COI). The assay works effectively with fecal DNA and is conveniently transferable to low-cost, high-throughput Illumina MiSeq technology that also allows simultaneous pairing with other markers. Our PCR primers target a region of COI that is highly discriminatory among Chiroptera (92% species-level identification of barcoded species), and are sufficiently degenerate to allow hybridization across diverse bat taxa. We successfully validated our system with 54 bat species across both suborders. Despite abundant arthropod prey DNA in guano, our primers were highly specific to bats; no arthropod DNA was detected in thousands of feces run on Sanger and Illumina platforms. The assay is extendable to fecal pellets of unknown age as well as individual and pooled guano, to allow for individual (using singular fecal pellets) and community (using combined pellets collected from across long-term roost sites) analyses. We developed a searchable database (http://nau.edu/CEFNS/Forestry/Research/Bats/Search-Tool/) that allows users to determine the discriminatory capability of our markers for bat species of interest. Our assay has applications worldwide for examining disease impacts on vulnerable species, determining species assemblages within roosts, and assessing the presence of bat species that are vulnerable or facing extinction. The development and analytical pathways are rapid, reliable, and inexpensive, and can be applied to ecology and conservation studies of other taxa.

16.
Anal Chem ; 86(5): 2308-13, 2014 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-24494709

RESUMO

The determination of trace elements using stripping voltammetry may be seriously affected by the presence of intensive matrix background or interfering peaks, leading to poorer detection limits and/or inaccurate quantitative results. In this work, we have tested the use of signal transformation (e.g., second derivative) in the analysis of platinum in seawater and sediment digests by means of catalytic adsorptive stripping voltammetry. In natural waters, the limit of detection of Pt is affected by a broad background wave due to the formazone complex used in the sample matrix for its determination, while in sediment digests, the Pt peak may be interfered with due to the presence of elevated concentrations of Zn, affecting the accuracy of the determination. Results applying second derivative signal transformation revealed a significant improvement (2-3-fold) of the detection limit in water due to the minimization of background effects, therefore allowing shorter accumulation times and faster determinations. In the presence of interfering peaks, the inaccuracy resulting from erroneous baseline selection in the original signal is eliminated when the second derivative is used. Signal processing should be considered as a useful tool for other voltammetric methodologies where more accurate or faster determinations are needed.

17.
Rev. bras. entomol ; 55(3): 454-456, July-Sept. 2011. tab
Artigo em Inglês | LILACS | ID: lil-602246

RESUMO

Mortality of Plutella xylostella (Lepidoptera, Plutellidae) by parasitoids in the Province of Santa Fe, Argentina. Plutella xylostella (Linnaeus, 1758) (Lepidoptera, Plutellidae) larvae cause severe economic damage on cabbage, Brassica oleracea L. variety capitata (Brassicaceae), in the horticultural fields in the Province of Santa Fe, Argentina. Overuse of broad spectrum insecticides affects the action of natural enemies of this insect on cabbage. The objectives of this work were to identify the parasitoids of P. xylostella and to determine their influence on larva and pupa mortality. Weekly collections of larvae and pupae were randomly conducted in cabbage crops during spring 2006 and 2007. The immature forms collected were classified according to their developmental stage: L1 and L2 (Ls = small larvae), L3 (Lm = medium larvae), L4 (Ll = large larvae), pre-pupae and pupae (P). Each individual was observed daily in the laboratory until the adult pest or parasitoid emergence. We identified parasitoids, the number of instar and the percentage of mortality of P. xylostella for each species of parasitoid. Parasitoids recorded were: Diadegma insulare (Cresson, 1875) (Hymenoptera, Ichneumonidae), Oomyzus sokolowskii (Kurdjumov, 1912) (Hymenoptera, Eulophidae), Cotesia plutellae (Kurdjumov, 1912) (Hymenoptera, Braconidae) and an unidentified species of Chalcididae (Hymenoptera). Besides parasitoids, an unidentified entomopathogenic fungus was also recorded in 2006 and 2007. In 2006, the most successful parasitoids were D. insulare and O. sokolowskii, while in 2007 only D. insulare exerted a satisfactory control and it attacked the early instars of the pest.


Mortalidade de Plutella xylostella (Lepidoptera, Plutellidae) por parasitóides na Província de Santa Fé, Argentina. Plutella xylostella (Linnaeus, 1758) (Lepidoptera, Plutellidae) causa danos econômicos severos em repolho, Brassica oleracea variedade capitata L. (Brassicaceae), na área de horticultura localizada na Província de Santa Fé, Argentina. O uso excessivo de inseticidas de largo espectro afeta a ação dos inimigos naturais de P. xylostella em repolho. O presente trabalho teve como objetivo identificar os parasitóides de P. xylostella e determinar sua influência na mortalidade de larvas e pupas em Santa Fé, Argentina. Coletas semanais de larvas e pupas em culturas de repolho foram realizadas aleatoriamente na área durante a primavera de 2006 e 2007, registradas pelo estágio de desenvolvimento: L1 e L2 (Ls = larvas pequenas), (Lm = larvas médias) L3, L4 (Ll = larvas grandes) pré-pupa e pupa (P). Cada indivíduo foi observado diariamente no laboratório até a emergência dos adultos da praga ou dos parasitóides. Foram identificadas as espécies de parasitóides o número de instars e a porcentagem de mortalidade. Os parasitóides registrados foram: Diadegma insulare (Cresson, 1875) (Hymenoptera, Ichneumonidae), Oomyzus sokolowskii (Kurdjumov, 1912) (Hymenoptera, Eulophidae), Cotesia plutellae (Kurdjumov, 1912) (Hymenoptera, Braconidae) e uma espécie não identificada pertencente à família Chalcididae. Além dos parasitóides, um fungo entomopatogênico não identificado foi registrado. Em 2006, os parasitóides mais bem sucedidos foram D. insulare e O. Sokolowskii; enquanto que em 2007 apenas D. insulare exerceu um controle satisfatório, atacando os instares iniciais da praga.

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