Robust chromatin state annotation.

With the goal of mapping genomic activity, international projects have recently measured epigenetic activity in hundreds of cell and tissue types. Chromatin state annotations produced by segmentation and genome annotation (SAGA) methods have emerged as the predominant way to summarize these epigenomic data sets in order to annotate the genome. These chromatin state annotations are essential for many genomic tasks, including identifying active regulatory elements and interpreting disease-associated genetic variation. However, despite the widespread applications of SAGA methods, no principled approach exists to evaluate the statistical significance of chromatin state assignments. Here, we propose the first method for assigning calibrated confidence scores to chromatin state annotations. Toward this goal, we performed a comprehensive evaluation of the reproducibility of the two most widely used existing SAGA methods, ChromHMM and Segway. We found that their predictions are frequently irreproducible. For example, when applying the same SAGA method on two sets of experimental replicates, 27%-69% of predicted enhancers fail to replicate. This suggests that a substantial fraction of predicted elements in existing chromatin state annotations cannot be relied upon. To remedy this problem, we introduce SAGAconf, a method for assigning a measure of confidence (r-value) to chromatin state annotations. SAGAconf works with any SAGA method and assigns an r-value to each genomic bin of a chromatin state annotation that represents the probability that the label of this bin will be reproduced in a replicated experiment. Thus, SAGAconf allows a researcher to select only the reliable predictions from a chromatin annotation for use in downstream analyses.

Precision enzyme discovery through targeted mining of metagenomic data.

Metagenomics has opened new avenues for exploring the genetic potential of uncultured microorganisms, which may serve as promising sources of enzymes and natural products for industrial applications. Identifying enzymes with improved catalytic properties from the vast amount of available metagenomic data poses a significant challenge that demands the development of novel computational and functional screening tools. The catalytic properties of all enzymes are primarily dictated by their structures, which are predominantly determined by their amino acid sequences. However, this aspect has not been fully considered in the enzyme bioprospecting processes. With the accumulating number of available enzyme sequences and the increasing demand for discovering novel biocatalysts, structural and functional modeling can be employed to identify potential enzymes with novel catalytic properties. Recent efforts to discover new polysaccharide-degrading enzymes from rumen metagenome data using homology-based searches and machine learning-based models have shown significant promise. Here, we will explore various computational approaches that can be employed to screen and shortlist metagenome-derived enzymes as potential biocatalyst candidates, in conjunction with the wet lab analytical methods traditionally used for enzyme characterization.

Computational study of inclusion complexes of V-type nerve agents (VE, VG, VM, VR and VX) with ß-cyclodextrin.

The effective detoxification of organophosphate (OP) nerve agents (OPNAs) is a challenging issue for scientists. The host-guest inclusion complexes of five V-type nerve agents (VE, VG, VM, VR and VX) with ß-cyclodextrin (ß-CD) have been studied by combining quantum mechanical (QM) calculations and molecular dynamics (MD) simulations. The frontier molecular orbital (FMO) and molecular electrostatic potential (MEP) have been analyzed to describe the reactivity parameters and electronic properties. The obtained results clearly reveal that stable complexes were formed in both vacuum and water media, and the complexation process occurred spontaneously. To understand non-covalent interactions, natural bond orbital (NBO) and quantum theory of atoms in molecules (QTAIM) have been used. IR and Raman spectra have been calculated to confirm the formation of complexes and also thermodynamic parameters have been investigated. It was demonstrated that in addition to van der Waals interactions, the presence of intermolecular hydrogen bonds enhances the stability of these complexes. Furthermore, MD simulations were carried out to get a better insight into the inclusion process of the above complexes. From MD simulations, all simulated systems reached full equilibration at 1000 ps and the V-agent molecules consistently remained in the ß-CD cavity and only had vibrational motion inside the cavity. More importantly, MD simulations support the findings of QM calculations and indicate that hydrogen bonding can help the leaving groups of V-agents to be released and them to be hydrolyzed. All results have shown that the VR agent formed the most stable complex with ß-CD molecule than that of other agents.Communicated by Ramaswamy H. Sarma.

Microplastics in atmospheric dust samples of Sistan: sources and distribution.

In this work, the amount and physical and chemical characteristics of airborne microplastics (MPs) pollution in dust samples in Sistan, located in the eastern part of Iran, is reported. Sampling stations were selected according to the wind direction and population density. MPs were collected by a static dust sampler and analyzed by optical microscopy and FT-IR spectroscopy. Results showed that the distribution frequency of MPs in residential and non-residential areas was 6 to 11 pieces per 100 g (pcs/100 g) with an average abundance of 9.8 pcs/100 g. Fragmented MPs were approximately consisted 64% of total MPs and their sizes were in the range of 0.9-3.8 mm. Polyethylene (49%), polystyrene (21%) and polyester (18%) were the main MPs presented in the dust samples. It was observed that population density and wind direction were the most important parameters affecting MPs pollution in dust. Supplementary Information: The online version contains supplementary material available at 10.1007/s40201-022-00833-y.

Effects of gallic acid on intraperitoneal adhesion bands in rats.

Objective: Gallic acid (GA) is an organic acid that possesses anti-inflammatory effects as it inhibits the production of metalloproteinases, tissue plasminogen activator, growth factors and adhesion molecules. Since formation of abdominal surgery-induced adhesion bands is accompanied by inflammation, angiogenesis and cell proliferation, in the current study, we assessed potential beneficial properties of GA against adhesion bands formation in rats. Materials and Methods: Thirty-six adult male rats were assigned into six groups of six animals. After induction of anesthesia, peritoneal injury was induced using a standard method and animals received either GA (10, 25, 50 and 100 mg/kg), or normal saline, while a group of rats remained intact. Seven days after the surgery, animals were decapitated and samples were collected for pathology evaluations. Also, lipid peroxidation (TBARS) and tumor necrosis factor alpha (TNF-α) levels were determined in serum samples. Results: Our results showed that GA significantly reduced lipid peroxidation in serum samples but had no effect on TNF-α levels. Furthermore, microscopic and macroscopic injuries reduced significantly in GA-treated animals. Conclusion: Since GA reduced adhesion bands formation at microscopic and macroscopic levels, it could be considered a treatment against adhesion bands formation.

Theoretical study on the mechanism and kinetics of the formation ß-carotene epoxides from the oxidative degradation of ß-carotene.

Some factors such as oxidation can significantly affect the level of ß-carotene after processing and during the storage of foods. Oxidative degradation of ß-carotene with the active forms of oxygen produces ß-carotene 5,6 and 5,8-epoxides. Two mechanisms involving a direct attack on the double bonds of the ß-carotene by 1O2 (a neutral mechanism) and 3O2 (a radical mechanism) oxygen have been proposed and considered kinetically and thermodynamically by the density functional theory method. It concluded that due to the smaller energy barrier in the first step, the neutral mechanism with 1O2 is a more desirable path than the diradical mechanism with 3O2 and this was in complete agreement with the experimental reality of more reactivity of 1O2. The energy barriers of the stepwise manner in the intersystem crossing pathway showed a more favorable pathway in the neutral mechanism. The deviation of spin contamination values was ignorable in the diradical mechanism.

A computational learning paradigm to targeted discovery of biocatalysts from metagenomic data: A case study of lipase identification.

The growing adoption of enzymes as biocatalysts in various industries has accentuated the demand for acquiring access to the great natural diversity and, in the meantime, the advent and advancements of metagenomics and high-throughput sequencing technologies have offered an unprecedented opportunity to explore this extensive resource. Lipases, enzymes responsible for the biological turnover of lipids, are among the most commercialized biocatalysts with numerous applications in different domains and therefore are of high industrial value. The relatively costly and time-consuming wet-lab experimental pipelines commonly used for novel enzyme discovery, highlight the necessity of agile in silico approaches to keep pace with the exponential growth of available sequencing data. In the present study, an in-depth analysis of a tannery wastewater metagenome, including taxonomic and enzymatic profiling, was performed. Using sequence homology-based screening methods and supervised machine learning-based regression models aimed at prediction of lipases' pH and temperature optima, the metagenomic data set was screened for lipolytic enzymes, which led to the isolation of alkaline and highly thermophilic novel lipase. Moreover, MeTarEnz (metagenomic targeted enzyme miner) software was developed and made freely accessible (at https://cbb.ut.ac.ir/MeTarEnz) as a part of this study. MeTarEnz offers several functions to automate the process of targeted enzyme mining from high-throughput sequencing data. This study highlights the competence of computational approaches in exploring vast biodiversity within environmental niches, while providing a set of practical in silico tools as well as a generalized methodology to facilitate the sequence-based mining of biocatalysts.

Evaluation of Multiplex/Nested Polymerase Chain Reaction and Loop-Mediated Isothermal Amplification for Malaria Diagnosis in Southeastern Iran.

Malaria is one of the most serious health problems in many countries, including Iran. Accurate diagnosis is important regardless of the elimination status of a country. A cross-sectional study was performed on 105 people who were suspected to be positive for malaria infection in Sistan and Baluchistan, Iran. Blood smears (thin and thick films) were stained with 10% Giemsa. DNA was extracted from the prepared thin and thick films for molecular methods. Multiplex/nested polymerase chain reaction (mn-PCR), loop-mediated isothermal amplification (LAMP), and light microscopy (LM) were compared with nested PCR (nPCR) as a gold standard. Of 105 subjects, 52 (49.5%), 58 (55.2%), 58 (55.2%), and 63 (60%) were positive for malaria by LM, nPCR, mn-PCR, and LAMP, respectively. The sensitivity, specificity, and kappa were 92.1%, 100%, and 0.9 for LAMP and 100%, 100%, and 1 for mn-PCR, respectively. Eight cases of coinfection (Plasmodium vivax and Plasmodium falciparum) that were not detected by LM method were diagnosed by mn-PCR and LAMP. In the present study, the high sensitivity and specificity of LAMP and mn-PCR indicate that these two tests are good alternatives to nPCR for malaria diagnosis.

Seroepidemiology of visceral leishmaniasis among free-roaming dogs and children in Zahedan city, southeast of Iran, 2018-2020.

BACKGROUND: Mediterranean visceral leishmaniasis (VL) or kala-azar is an endemic zoonotic disease in Iran. Domestic dogs are the primary reservoir host and source of VL infection. The high-risk populations are children and immune-deficient adults. OBJECTIVE: Based on the lack of published reports about the VL in Sistan and Baluchestan province in the southeast of Iran, this study aimed to assess the seroprevalence of diseae in free-roaming dogs and children under 12 years old using indirect fluorescent antibody (IFA) test. METHODS: This cross-sectional study was performed between 2018 and 2020 in Zahedan city, Sistan, and Baluchestan province. Blood samples were taken from 400 children under 12 years old with a fever history accompanied by at least another specific clinical presentation. In the same period, blood samples were collected from 150 stray dogs. Demographic characteristics and clinical manifestations in both humans and dogs were recorded. The IFA test examined all blood samples for the detection of anti-Leishmania infantum antibodies. RESULTS: Overall, the IFA test results were positive in 8 dogs (5.33%). Only two seropositive dogs (25%) showed obvious clinical symptoms. There was a significant correlation between the positive cases, clinical signs (P = 0.046), and age (P = 0.037) in infected dogs. None of the collected sera from 400 febrile children were positive. CONCLUSION: According to the present finding, it seems that VL is not endemic in Zahedan city, Sistan, and Baluchestan province, but the domestic cycle of L. infantum has been established in this area. Further investigations would be needed to estimate the status of VL infection in wild canines as a secondary potential reservoir host. Furthermore, periodic monitoring of disease must not be neglected.

Molecular Characterization and Phylogeny of Taenia hydatigena and Echinococcus granulosus from Iranian Sheep and Cattle Based on COX1 Gene.

Hydatid cyst, the larval stage of Echinococcus granulosus, and Cysticercus tenuicollis, the larval stage of Taenia hydatigena, are prevalent in domestic, livestock, and wild ruminants. The main goal of this research was to identify the isolates of E. granulosus and C. tenuicollis by partial sequencing with PCR amplification of the cytochrome C oxidase 1 (COX1) gene. During a routine veterinary inspection at a Chabahar city slaughterhouse, two samples of hydatid cysts from sheep's liver and cattle's lung and two samples of C. tenuicollis from sheep's liver were collected. After DNA extraction, the fragment of the COX1 gene was amplified by the PCR method. Sample sequences were modified and synchronized by Chromas and CLC genomic workbench 11 software. Sequence analysis was carried out by BLAST algorithms and GenBank databases. Phylogenetic trees were performed using MEGA 7 software and the neighbor-joining and maximum likelihood method for T. hydatigena and E. granulousus. The result indicated that the main genotype of parasites and the amplified fragment size were G1 and approximately 455 bp, respectively. The analysis of phylogenetic trees based on nucleic acid for four samples showed that there was a common ancestor. However, the shift in nucleotides in the two isolates in E. granulosus and the two isolates of T. hydatigena were non-synonymous type and synonymous type, respectively. The present study showed that the dominant genotype in all isolates was G1 and this report was similar to other studies in Iran and the world. Also, the partial COX1 gene sequence was matched with T. hydatigena.

Full Kinetics and Mechanism Investigation for Generating 4-Substituted 1, 4- Dihydropyridine Derivatives in the Presence of Green Catalyst and Aqueous Medium: Experimental Procedure.

AIMS AND OBJECTIVE: The main objective of the kinetic investigation of the reaction between ethyl acetoacetate 1, ammoniumacetat 2, dimedone 3, and diverse substitutions of benzaldehyde 4-X, (X= H, NO2, CN, CF3, Cl, CH (CH3)2, CH3, OCH3, OCH3, and OH) for generating 4-substituted 1, 4-dihydropyridine derivatives (product 5) was to recognize the most realistic reaction mechanism. The layout of the reaction mechanism was studied kinetically via a UV-visible spectrophotometry approach. MATERIALS AND METHODS: Among the various mechanisms, only mechanism1 (path1) involving 12 steps was recognized as a dominant mechanism (path1). Herein, the reactions between 1 and 2 (kobs= 814.04 M-1.min-1) and also between 3 and 4-H (kobs= 151.18 M-1.min-1) can be accepted as the first and second steps (step1 and step2) of the reaction mechanism, respectively. Amongst all steps, only step9 of the dominant mechanism (path1) comprised substituent groups (X) near the reaction center. RESULTS AND DISCUSSION: Para electron-withdrawing or donating groups on the compound 4-X increased the rate of the reaction 4 times more or decreased 8.7 times less than the benzaldehyde alone. So, this step is sensitive for monitoring any small or huge changes in the reaction rate. Accordingly, step9 is the rate-determining step of the reaction mechanism (path1). CONCLUSION: The recent result is in agreement with the Hammett description of an excellent dual substituent factor (r = 0.990) and positive value of reaction constant (ρ= +0.9502), which confirms that both the resonance and inductive effects "altogether" contribute to the reaction center of step9 in the dominant mechanism (path1).

A generalized machine-learning aided method for targeted identification of industrial enzymes from metagenome: A xylanase temperature dependence case study.

Growing industrial utilization of enzymes and the increasing availability of metagenomic data highlight the demand for effective methods of targeted identification and verification of novel enzymes from various environmental microbiota. Xylanases are a class of enzymes with numerous industrial applications and are involved in the degradation of xylose, a component of lignocellulose. The optimum temperature of enzymes is an essential factor to be considered when choosing appropriate biocatalysts for a particular purpose. Therefore, in silico prediction of this attribute is a significant cost and time-effective step in the effort to characterize novel enzymes. The objective of this study was to develop a computational method to predict the thermal dependence of xylanases. This tool was then implemented for targeted screening of putative xylanases with specific thermal dependencies from metagenomic data and resulted in the identification of three novel xylanases from sheep and cow rumen microbiota. Here we present thermal activity prediction for xylanase, a new sequence-based machine learning method that has been trained using a selected combination of various protein features. This random forest classifier discriminates non-thermophilic, thermophilic, and hyper-thermophilic xylanases. The model's performance was evaluated through multiple iterations of sixfold cross-validations as well as holdout tests, and it is freely accessible as a web-service at arimees.com.

MCIC: Automated Identification of Cellulases From Metagenomic Data and Characterization Based on Temperature and pH Dependence.

As the availability of high-throughput metagenomic data is increasing, agile and accurate tools are required to analyze and exploit this valuable and plentiful resource. Cellulose-degrading enzymes have various applications, and finding appropriate cellulases for different purposes is becoming increasingly challenging. An in silico screening method for high-throughput data can be of great assistance when combined with the characterization of thermal and pH dependence. By this means, various metagenomic sources with high cellulolytic potentials can be explored. Using a sequence similarity-based annotation and an ensemble of supervised learning algorithms, this study aims to identify and characterize cellulolytic enzymes from a given high-throughput metagenomic data based on optimum temperature and pH. The prediction performance of MCIC (metagenome cellulase identification and characterization) was evaluated through multiple iterations of sixfold cross-validation tests. This tool was also implemented for a comparative analysis of four metagenomic sources to estimate their cellulolytic profile and capabilities. For experimental validation of MCIC's screening and prediction abilities, two identified enzymes from cattle rumen were subjected to cloning, expression, and characterization. To the best of our knowledge, this is the first time that a sequence-similarity based method is used alongside an ensemble machine learning model to identify and characterize cellulase enzymes from extensive metagenomic data. This study highlights the strength of machine learning techniques to predict enzymatic properties solely based on their sequence. MCIC is freely available as a python package and standalone toolkit for Windows and Linux-based operating systems with several functions to facilitate the screening and thermal and pH dependence prediction of cellulases.

A novel high performance in-silico screened metagenome-derived alkali-thermostable endo-ß-1,4-glucanase for lignocellulosic biomass hydrolysis in the harsh conditions.

BACKGROUND: Lignocellulosic biomass, is a great resource for the production of bio-energy and bio-based material since it is largely abundant, inexpensive and renewable. The requirement of new energy sources has led to a wide search for novel effective enzymes to improve the exploitation of lignocellulose, among which the importance of thermostable and halotolerant cellulase enzymes with high pH performance is significant. RESULTS: The primary aim of this study was to discover a novel alkali-thermostable endo-ß-1,4-glucanase from the sheep rumen metagenome. At first, the multi-step in-silico screening approach was utilized to find primary candidate enzymes with superior properties. Among the computationally selected candidates, PersiCel4 was found and subjected to cloning, expression, and purification followed by functional and structural characterization. The enzymes' kinetic parameters, including Vmax, Km, and specific activity, were calculated. The PersiCel4 demonstrated its optimum activity at pH 8.5 and a temperature of 85 °C and was able to retain more than 70% of its activity after 150 h of storage at 85 °C. Furthermore, this enzyme was able to maintain its catalytic activity in the presence of different concentrations of NaCl and several metal ions contains Mg2+, Mn2+, Cu2+, Fe2+ and Ca2+. Our results showed that treatment with MnCl2 could enhance the enzyme's activity by 78%. PersiCel4 was ultimately used for enzymatic hydrolysis of autoclave pretreated rice straw, the most abundant agricultural waste with rich cellulose content. In autoclave treated rice straw, enzymatic hydrolysis with the PersiCel4 increased the release of reducing sugar up to 260% after 72 h in the harsh condition (T = 85 °C, pH = 8.5). CONCLUSION: Considering the urgent demand for stable cellulases that are operational on extreme temperature and pH conditions and due to several proposed distinctive characteristics of PersiCel4, it can be used in the harsh condition for bioconversion of lignocellulosic biomass.

A novel thermostable cellulase cocktail enhances lignocellulosic bioconversion and biorefining in a broad range of pH.

Lignocellulose is the most abundant biomass in nature, and the effective biorefining of them is dependent upon enzymes with high catalytic activity and stability in extreme pH and high temperatures. Due to the molecular constraints for a single enzyme, obtaining a more excellent active pH range can be more easily achievable through the simultaneous activity of two or more enzymes in a cocktail. To address this, we attempted to develop a cocktail of novel thermostable cellulases with high hydrolytic ability and stability. Two cellulases were mined, identified, cloned, and expressed from the camel rumen microbiota. The PersiCel1 demonstrated its maximum relative activity at the pH of 8, and the temperature of 60 °C and the PersiCel2 was optimally active at the pH of 5 and the temperature of 50 °C. Furthermore, utilization of the enzyme cocktail implies the synergistic relationship and significantly increased the saccharification yield of lignocellulosic substrates up to 71.7% for sugar-beet pulp (active pH range of 4-9) and 138.7% for rice-straw (active pH range of 5-8), compared to maximum hydrolysis of Persicel1 or PersiCel2 separately at 55 °C. Our results indicate the probable applicability of PersiCel1, PersiCel2, and their cocktail in numerous industries, specifically biorefineries and lignocellulose bioconversion based technologies.

Serological and molecular diagnosis of Toxoplasma gondii in patients with schizophrenia.

Schizophrenia is a persistent neuropsychiatric syndrome of uncertain source. Toxoplasmosis is the most prevalent parasitic protozoan infecting one-third of the worldwide human population. Infectious agents such as toxoplasma are the probable cause of schizophrenia. This study was aimed to evaluate the association between schizophrenia and toxoplasmosis using SAG1 and B1 Target gene. During February to December 2016, 92 patients with schizophrenia are imported in our study. All cases were assessed by serological (IgG and IgM antibodies) and molecular examinations. ELISA was performed by Commercial kits according to manufactures procedure. DNA was extracted and nested PCR was done using two pairs of primers. From 92 patients, 59 (64.13%) cases were positive for toxoplasmosis by serological examinations (14 samples positive for IgM and IgG, 40 samples positive for only IgG and 5 samples Positive for only IgM) and 58 (63.04%) were positive by Nested PCR technique. Based on the nested PCR method, 68.47 and 47.82% of samples were positive by B1 and SAG1 genes, respectively. Our results showed the importance of use both serological and molecular diagnostic methods for accurate recognition of T. gondii in patients with schizophrenia. Moreover our results indicated that B1 gene is more sensitive than SAG1 gene.

Synthesis and Kinetics of Highly Substituted Piperidines in the Presence of Tartaric Acid as a Catalyst.

Aim & Scope: The synthesis of highly substituted piperidine from the one-pot reaction between aromatic aldehydes, anilines and ß-ketoesters in the presence of tartaric acid as a catalyst has been investigated in both methanol and ethanol media at ambient temperature. Different conditions of temperature and solvent were employed for calculating the thermodynamic parameters and obtaining an experimental approach to the kinetics and mechanism. Experiments were carried out under different temperature and solvent conditions. MATERIAL AND METHODS: Products were characterized by comparison of physical data with authentic samples and spectroscopic data (IR and NMR). Rate constants are presented as an average of several kinetic runs (at least 6-10) and are reproducible within ± 3%. The overall rate of reaction is followed by monitoring the absorbance changes of the products versus time on a Varian (Model Cary Bio- 300) UV-vis spectrophotometer with a 10 mm light-path cell. RESULTS: The best result was achieved in the presence of 0.075 g (0.1 M) of catalyst and 5 mL methanol at ambient temperature. When the reaction was carried out under solvent-free conditions, the product was obtained in a moderate yield (25%). Methanol was optimized as a desirable solvent in the synthesis of piperidine, nevertheless, ethanol in a kinetic investigation had none effect on the enhancement of the reaction rate than methanol. Based on the spectral data, the overall order of the reaction followed the second order kinetics. The results showed that the first step of the reaction mechanism is a rate determining step. CONCLUSION: The use of tartaric acid has many advantages such as mild reaction conditions, simple and readily available precursors and inexpensive catalyst. The proposed mechanism was confirmed by experimental results and a steady state approximation.

Structural effects on kinetics and a mechanistic investigation of the reaction between DMAD and N-H heterocyclic compound in the presence of triphenylarsine: spectrophotometry approach.

Kinetics and a mechanistic investigation of the reaction between dimethyl acetylenedicarboxcylate (DMAD) and saccharin (N-H heterocyclic compound) has been spectrally studied in methanol environment in the presence of triphenylarsine (TPA) as a catalyst. Previously, in a similar reaction, triphenylphosphine (TTP) (instead of triphenylarsine) has been employed as a third reactant (not catalyst) for the generation of an ylide (final product) while, in the present work the titled reaction in the presence of TPA leaded to the especial N-vinyl heterocyclic compound with different kinetics and mechanism. The reaction followed second order kinetics. In the kinetic study, activation energy and parameters (Ea, ΔH‡, ΔS‡ and ΔG‡) were determined. Also, the structural effect of the N-H heterocyclic compound was investigated on the reaction rate. The result showed that reaction rate increases in the presence of isatin (N-H compound) that participates in the second step (step2), compared to saccharin (another N-H compound). This was a good demonstration for the second step (step2) of the reaction that could be considered as the rate- determining step (RDS). As a significant result, not only a change in the structure of the reactant (TPA instead of TPP) creates a different product, but also kinetics and the reaction mechanism have been changed.

Epidemiological Study of Toxocar canis in Children under 14-Years-Old and Dogs in Zabol and Chabahar Districts, Southeast of Iran.

BACKGROUND: The purpose of this study was seroepidemiological and parasitological assessment of Toxocara canis infection in children and dogs in Zabol and Chabahar, Iran. METHODS: This study was a descriptive-analytic study with a simple random sampling of children under 14 yr old, referring to urban, rural, and tribal laboratories of Zabol and Chabahar, Sistan and Baluchestan Province, Iran in 2016. Demographic data, clinical, and laboratory conditions of patients were collected through interviews, questionnaires, and blood count measuring. The prevalence of IgG antibodies against T. canis was assessed by ELISA. T. canis eggs in dogs (as the original host) were also assessed by examining animal feces. Then the data were analyzed using SPSS 19 software and descriptive statistics, chi-square and ANOVA statistical tests. RESULTS: Totally, 364 patients were enrolled, of which 51.6% were female and mean±SD age of participants was 7.2 (±3.7) yr. IgG antibodies against T. canis was observed in 3.8% of cases. A significant association was found between the seroprevalence of T. canis and eosinophil (P=0.003) and red blood cell count (P=0.04). We also found a significant association between serological prevalence of T. canis and demographic parameters, such as city of residence (P=0.003), gender (P=0.04), consumption of vegetables (P=0.01), and the living place (P=0.04). Mean antibody titration was 2.2 ±1.1, with statistically significant difference among age groups (P=0.001). In addition, T. canis infection was positive in 27.5% of dogs living in the study areas. CONCLUSION: High risk of infection represented in patients referring to laboratories of Zabol and Chabahar. In addition, given the fact that dogs are the final hosts to transfer Toxocara infection to humans, this study emphasizes the need to control the population of stray dogs in the region to prevent the development of disease in the human society.

Kinetic Spectrophotometric Method for the 1,4-Diionic Organophosphorus Formation in the Presence of Meldrum's Acid: Stopped-Flow Approach.

The kinetics of the reaction between triphenylphosphine (TPP) and dimethyl acetylenedicarboxylate (DMAD) in the presence of Meldrum's acid (MA) for the generation of the 1,4-diionic organophosphorus compound has been investigated using the stopped-flow and UV-VIS spectrophotometry techniques. The first step of the reaction between TPP and DMAD for the generation of (I1) in ethanol was followed by the stopped-flow apparatus. This step was recognized as a fast step. The reaction between the intermediate (I1) and MA showed first-order kinetics, and it was followed by the UV-VIS spectrophotometry technique. The activation parameters for the slow step of the proposed mechanism were determined using two linearized forms of the Eyring equation. From the temperature, concentration and solvent studies, the activation energy (Ea = 20.16 kJ·mol-1) and the related activation parameters (ΔG‡ = 71.17 ± 0.015 kJ·mol-1, ΔS‡ = -185.49 ± 0.026 J·mol-1 and ΔH‡ =17.72 ± 0.007 kJ·mol-1) were calculated. The experimental data indicated that the reaction was zero-order in MA and second-order overall. The proposed mechanism was confirmed with the observed kinetic data obtained from the UV-VIS and stopped-flow techniques.