Publications by authors named "Jose Luis Ramirez"

Biocontrol agents play a pivotal role in managing pests and contribute to sustainable agriculture. Recent advancements in genetic engineering can facilitate the development of entomopathogenic fungi with desired traits to enhance biocontrol efficacy. In this study, a CRISPR-Cas9 ribonucleoprotein system was utilized to genetically improve the virulence of Beauveria bassiana, a broad-spectrum insect pathogen used in biocontrol of arthropod pests worldwide.

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Article Synopsis
  • * The research involved standard bioassays to assess resistance against various insecticides, along with biochemical tests to identify metabolic resistance mechanisms and real-time PCR for detecting specific genetic mutations (Kdr).
  • * The findings revealed significant resistance levels in multiple strains of Aedes mosquitoes, with notable variation in enzyme activity related to resistance, and identified the presence of Kdr mutations in several populations, indicating a pressing public health challenge.
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This paper presents the integration of a sensing layer over interdigitated electrodes and an electronic circuit on the same flexible printed circuit board. This integration provides an effective technique to use this design as a wearable gas measuring system in a target application, exhibiting high performance, low power consumption, and being lightweight for on-site monitoring. The wearable system proves the concept of using an NFC tag combined with a chemoresistive gas sensor as a cumulative gas sensor, having the possibility of holding the data for a working day, and completely capturing the exposure of a person to NO concentrations.

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Background And Objective: Neoadjuvant chemotherapy (NAC) followed by cystectomy is the standard of care in muscle-invasive bladder cancer (MIBC). Pathological response has been associated with longer survival, but no currently available clinicopathological variables can identify patients likely to respond, highlighting the need for predictive biomarkers. We sought to identify a predictive signature of response to NAC integrating clinical score, taxonomic subtype, and gene expression.

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Tar spot disease in corn, caused by , can reduce grain yield by limiting the total photosynthetic area in leaves. Stromata of are long-term survival structures that can germinate and release spores in a gelatinous matrix in the spring, which are thought to serve as inoculum in newly planted fields. In this study, overwintered stromata in corn leaves were collected in Central Illinois, surface sterilized, and caged on water agar medium.

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Chagas disease, caused by infections, is included in the group of neglected diseases, and efforts to develop new therapeutic or immunoprevention approaches have not been successful. After the publication of the genome, the number of molecular and biochemical studies on this parasite has increased considerably, many of which are focused on families of variant surface proteins, especially trans-sialidases, mucins, and mucin-associated proteins. The disperse gene protein 1 family (DGF-1) is one of the most abundant families in the genome; however, the large gene size, high copy numbers, and low antibody titers detected in infected humans make it an unattractive study target.

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Article Synopsis
  • The study investigates the treatment failure of oral Chagas disease (oCD) in Venezuela, despite close supervision of patients receiving nitroheterocyclic drugs since its emergence in 2007.
  • Researchers analyzed blood samples and hemoculture isolates from nine patients, identifying significant genetic variability in parasite populations before and after treatment.
  • Findings suggest a connection between poor drug response and the presence of resistant parasite clones, emphasizing the importance of understanding drug susceptibility for effective treatment guidelines in the region.
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Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) is a multisystem and progressive neurodegenerative mitochondrial disease, caused by point nucleotide changes in the mtDNA where 80 % of cases have the mutation m.3243A>G in the MT-TL1 gene. In this work, we described the clinical, biochemical and molecular analysis of three Venezuelan patients affected with MELAS syndrome.

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Imaging techniques based on mass spectrometry or spectroscopy methods inform about the chemical composition of biological tissues or organisms, but they are sometimes limited by their specificity, sensitivity, or spatial resolution. Multimodal imaging addresses these limitations by combining several imaging modalities; however, measuring the same sample with the same preparation using multiple imaging techniques is still uncommon due to the incompatibility between substrates, sample preparation protocols, and data formats. We present a multimodal imaging approach that employs a gold-coated nanostructured silicon substrate to couple surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS) and surface-enhanced Raman spectroscopy (SERS).

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In the phase II MAJA trial, maintenance therapy with vinflunine resulted in longer progression-free survival compared to best supportive care in advanced urothelial cell carcinoma (aUCC) patients who did not progress after first-line platinum-based chemotherapy. However, despite an initial benefit observed in some patients, unequivocal resistance appears which underlying mechanisms are presently unknown. We have performed gene expression and functional enrichment analyses to shed light on the discovery of these underlying resistance mechanisms.

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Trypanosoma cruzi uses various mechanisms of infection to access humans. Since 1967, food contaminated with metacyclic trypomastigotes has triggered several outbreaks of acute infection of Chagas disease by oral transmission. Follow-up studies to assess the effectiveness of anti-parasitic treatment of oral outbreaks are rather scarce.

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Background: More than 85% of the malaria cases in Panama occur in poor, rural and indigenous regions like Darien Province. Vector diversity, infection rate and spatial distribution are important entomological parameters of malaria transmission dynamics. Their understanding is crucial for the development of effective disease control strategies.

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Culturing the entomopathogenic fungus, , under high glucose concentrations coupled with high aeration results in a fungal developmental shift from hyphal growth to mostly blastospores (yeast-like cells). The underlying molecular mechanisms involved in this shift remain elusive. A systematic transcriptome analysis of the differential gene expression was preformed to uncover the fungal transcriptomic response to osmotic and oxidative stresses associated with the resulting high blastospore yield.

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Background: Wolbachia bacteria are widely distributed throughout terrestrial arthropod species. These bacteria can manipulate reproduction and influence the vector competence of their hosts. Recently, Wolbachia have been integrated into vector control programmes for mosquito management.

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Retrotransposon Hot Spot (RHS) is the most abundant gene family in with unknown function in this parasite. The aim of this work was to shed light on the organization and expression of RHS in The diversity of the RHS protein family in was demonstrated by phylogenetic and recombination analyses. Transcribed sequences carrying the RHS domain were classified into ten distinct groups of monophyletic origin.

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Hemocytes limit the capacity of mosquitoes to transmit human pathogens. Here we profile the transcriptomes of 8506 hemocytes of and mosquito vectors. Our data reveal the functional diversity of hemocytes, with different subtypes of granulocytes expressing distinct and evolutionarily conserved subsets of effector genes.

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On 15 July 2020 was the 15th anniversary of the Magazine issue that reported three trypanosomatid genomes, namely , , and . That publication was a milestone for the research community working with trypanosomatids, even more so, when considering that the first draft of the human genome was published only four years earlier after 15 years of research. Although nowadays, genome sequencing has become commonplace, the work done by researchers before that publication represented a huge challenge and a good example of international cooperation.

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Background & Objectives: In Venezuela, Chagas disease (ChD) is considered a serious health problem, with about 6 million people at risk; and acute outbreaks due to oral transmission of Chagas Disease (OChD) are becoming increasingly important. In 2007 there was a major outbreak of OChD and although patients from this episode were treated with nifurtimox (Lampit®-Bayer), about 70% therapeutic failure was registered. These results led us to examine whether parasite's drug susceptibility was related to this therapeutic failure.

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An Evolutionary View of Telomeres.

Front Cell Infect Microbiol

September 2020

Like in most eukaryotes, the linear chromosomes of end in a nucleoprotein structure called the telomere, which is preceded by regions of variable length called subtelomeres. Together telomeres and subtelomeres are dynamic sites where DNA sequence rearrangements can occur without compromising essential interstitial genes or chromosomal synteny. Good examples of subtelomeres involvement are the expansion of human olfactory receptors genes, variant surface antigens in , and mating types.

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Many sensors are developed over flexible substrates to be used as wearables, which does not guarantee that they will actually withstand being bent. This work evaluates the gas sensing performance of metal oxide devices of three different types, before and after having undergone automated, repetitive bending tests. These tests were aimed at demonstrating that the fabricated sensors were actually flexible, which cannot be taken for granted beforehand.

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