in vitro response of Colletotrichum to chitosan. Effect on incidence and quality on tropical fruit. Enzymatic expression in mango

Colletotrichum is considered one of the fungal genera with the greatest diversity of species of phytopathogenic fungi and with a wide range of hosts including tropical fruits. In this study, the concentration of chitosan applied was a key factor in the in vitro inhibition of the three Colletotrichum isolates with the most sensitive being the one from banana. Germination was the development stage most affected by the application of this polymer. At the end of 10 days of storage, control of anthracnose in soursop, mango and banana fruit was considerable with the application of 1 % chitosan, with 80 to 100 % inhibition. Likewise, the ripening process of fruit with and without chitosan was generally similar. Activity of the peroxidase (POD) and polyphenol oxidase (PPO) enzymes was observed only in fruit of mango cv. 'Tommy Atkins,' inoculated and non-inoculated with C. gloeosporioides, the activity of both enzymes was higher in the chitosan treatments and the 1.0 % concentration was able to induce gene expression of POD and PPO, occurring until 24 h

in vitro response of Colletotrichum to chitosan. Effect on incidence and quality on tropical fruit. Enzymatic expression in mango

Colletotrichum is considered one of the fungal genera with the greatest diversity of species of phytopathogenic fungi and with a wide range of hosts including tropical fruits. In this study, the concentration of chitosan applied was a key factor in the in vitro inhibition of the three Colletotrichum isolates with the most sensitive being the one from banana. Germination was the development stage most affected by the application of this polymer. At the end of 10 days of storage, control of anthracnose in soursop, mango and banana fruit was considerable with the application of 1 % chitosan, with 80 to 100 % inhibition. Likewise, the ripening process of fruit with and without chitosan was generally similar. Activity of the peroxidase (POD) and polyphenol oxidase (PPO) enzymes was observed only in fruit of mango cv. 'Tommy Atkins,' inoculated and non-inoculated with C. gloeosporioides, the activity of both enzymes was higher in the chitosan treatments and the 1.0 % concentration was able to induce gene expression of POD and PPO, occurring until 24 h

Social and environmental factors in the diversity of tomato landraces from the South-Central region of Mexico

ABSTRACT: In the present study, we investigated the influence of social and environmental factors in the genetic diversity of tomato landraces in the South-Central region of Mexico. A total of 30 tomato landraces, collected in 18 villages with different ethnolinguistic affiliations, were analyzed. We reported that the genetic diversity of tomato landraces is associated with the ethnolinguistic group, weather, and soil-type present in the region studied. Our results showed that there are morphological differences between landraces grown by different ethnolinguistic groups; however, there was also evidence of morphological similarities between landraces from groups with different ethnolinguistic affiliations. Finally, different selection criteria, mainly fruit color, size and shape, plays an important role in the phenotypic divergence among landraces grown in different traditional farming systems

Effectiveness of a diagnostic algorithm for dengue based on an artificial neural network

Introduction Dengue is a disease with a wide clinical spectrum. The early identification of dengue cases is crucial but challenging for health professionals; therefore, it is necessary to have effective diagnostic instruments to initiate timely care. Objective To evaluate the effectiveness of an algorithm based on an artificial neural network (ANN) to diagnose dengue in an endemic area. Methods A single-center case–control study was conducted in a secondary-care hospital in Ciudad Obregón, Sonora. An algorithm was built with the official operational definitions, which was called the “direct algorithm,” and for the ANN algorithm, the brain.js library was used. The data analysis was performed with the diagnostic tests of sensitivity, specificity, positive predictive value (ppv), and negative predictive value (npv), with 95% confidence intervals and Cohen's kappa index. Results A total of 233 cases and 233 controls from 2022 were included. The ANN presented a sensitivity of 0.90 (95% CI [0.85, 0.94]), specificity of 0.82 (95% CI [0.77, 0.87]), npv of 0.91 (95% CI [0.87, 0.94]) and ppv of 0.81 (95% CI [0.76, 0.85]) and a kappa of 0.72. The direct algorithm had a sensitivity of 0.97 (95% CI [0.94, 0.99]), specificity of 0.96 (95% CI [0.92, 0.98]), npv 0.97 (95% CI [0.94, 0.98]), ppv 0.96 (95% CI [0.93, 0.98]) and kappa 0.93. Conclusions The direct algorithm performed better than the ANN in the diagnosis of dengue

Predict the incidence of Guillain Barré Syndrome and arbovirus infection in Mexico, 2014-2019.

The Dengue (DENV), Zika (ZIKV), and Chikungunya (CHIKV) virus infections have been linked to Guillain-Barré syndrome (GBS). GBS has an estimated lethality of 4% to 8%, even with effective treatment. Mexico is considered a hyperendemic country for DENV due to the circulation of four serotypes, and the ZIKV and CHIKV viruses have also been circulating in the country. The objective of this study was to predict the number of GBS cases in relation to the cumulative incidence of ZIKV / DENV / CHIKV in Mexico from 2014 to 2019. A six-year time series ecological study was carried out from GBS cases registered in the Acute Flaccid Paralysis (AFP) Epidemiological Surveillance System (ESS), and DENV, ZIKV and CHIKV estimated cases from cases registered in the epidemiological vector-borne diseases surveillance system. The results shows that the incidence of GBS in Mexico is positively correlated with DENV and ZIKV. For every 1,000 estimated DENV cases, 1.45 GBS cases occurred on average, and for every 1,000 estimated ZIKV cases, 1.93 GBS cases occurred on average. A negative correlation between GBS and CHIKV estimated cases was found. The increase in the incidence of GBS cases in Mexico can be predicted by observing DENV and ZIKV cases through the epidemiological surveillance systems. These results can be useful in public health by providing the opportunity to improve capacities for the prevention of arbovirus diseases and for the timely procurement of supplies for the treatment of GBS

Zika and dengue but not chikungunya are associated with Guillain-Barré syndrome in Mexico: A case-control study.

Background Zika, dengue and chikungunya viruses (ZIKV, CHIKV and DENV) are temporally associated with neurological diseases, such as Guillain-Barré syndrome (GBS). Because these three arboviruses coexist in Mexico, the frequency and severity of GBS could theoretically increase. This study aims to determine the association between these arboviruses and GBS in a Mexican population and to establish the clinical characteristics of the patients, including the severity of the infection. A case-control study was conducted (2016/07/01-2018/06/30) in Instituto Mexicano del Seguro Social (Mexican Social Security Institute) hospitals, using serum and urine samples that were collected to determine exposure to ZIKV, DENV, CHIKV by RT-qPCR and serology (IgM). For the categorical variables analysis, Pearson's χ2 or Fisher exact tests were used, and the Mann-Whitney U test for continuous variables. To determine the association of GBS and viral infection diagnosis through laboratory and symptomatology before admission, we calculated the odds ratio (OR) and 95% confidence intervals (95%CI) using a 2x2 contingency table. A p-value ≤ 0.05 was considered as significant. Ninety-seven GBS cases and 184 controls were included. The association of GBS with ZIKV acute infection (OR, 8.04; 95% CI, 0.89-73.01, p = 0.047), as well as laboratory evidence of ZIKV infection (OR, 16.45; 95% CI, 2.03-133.56; p = 0.001) or Flavivirus (ZIKV and DENV) infection (OR, 6.35; 95% CI, 1.99-20.28; p = 0.001) was observed. Cases of GBS associated with ZIKV demonstrated a greater impairment of functional status and a higher percentage of mechanical ventilation. According to laboratory results, an association between ZIKV or ZIKV and DENV infection in patients with GBS was found. Cases of GBS associated with ZIKV exhibited a more severe clinical picture. Cases with co-infection were not found