Rebeca D. Martínez Contreras

• PhD
• Principal Investigator at Meritorious Autonomous University of Puebla

Identification of the emerging multidrug-resistant yeast Candida auris is challenging. Here, we describe the role of the Mexico national reference laboratory Instituto de Diagnóstico y Referencia Epidemiológicos Dr. Manuel Martínez Báez (InDRE) and the Mexican national laboratory network in the identification of C. auris. Reference identification o...

Identification of the emerging multidrug resistant yeast Candida auris is challenging. Here we described the role of the Mexico national reference laboratory Instituto de Diagnóstico y Referencia Epidemiológicos Dr. Manuel Martínez Báez (InDRE) and the Mexican national laboratory network in the identification of C. auris . Reference identification...

Crataegus sp. is a tree that grows in temperate zones with worldwide distribution and is commonly known in Mexico as tejocote. The use of products derived from Crataegus in traditional medicine, food, and cosmetics has increased over the last few years and the relevance of this plant has also grown. Here, we report a disease that was observed in te...

Introduction Several plant-beneficial bacteria have the capability to promote the growth of plants through different mechanisms. The survival of such bacteria could be affected by environmental abiotic factors compromising their capabilities of phytostimulation. One of the limiting abiotic factors is low water availability. Materials and Methods I...

Bacteria continually face adverse conditions in the environment, which represent a stressor and restrict their survival. Among these factors, we could mention the following: the limitation of water, fluctuations in temperature, extreme pH values, high salt concentrations, exposure to ultraviolet radiation, and others. The present review focuses on...

Background: Despite dramatic advances in cancer treatment that lead to long-term survival, there is an increasing number of patients presenting with clinical manifestations of cerebral metastasis in breast cancer, for whom only palliative treatment options exist. Objective: The present review aims to provide to identify recent patens of breast c...

Stanhopea tigrina is a Mexican endemic orchid reported as a threatened species. The naturally occurring microorganisms present in S. tigrina are unknown. In this work, we analyzed the diversity of endophytic and epiphytic culturable fungi in S. tigrina according to morphological and molecular identification. Using this combined approach, in this st...

Alternative splicing is a key mechanism determinant for gene expression in metazoan. During alternative splicing, non-coding sequences are removed to generate different mature messenger RNAs due to a combination of sequence elements and cellular factors that contribute to splicing regulation. A different combination of splicing sites, exonic or int...

Gibberellins (GAs) are natural complex biomolecules initially identified as secondary metabolites in the fungus Gibberella fujikuroi with strong implications in plant physiology. GAs have been identified in different fungal and bacterial species, in some cases related to virulence, but the full understanding of the role of these metabolites in the...

Alternative splicing is a key molecular mechanism now considered as a hallmark of cancer that has been associated with the expression of distinct isoforms during the onset and progression of the disease. The leading cause of cancer-related deaths in women worldwide is breast cancer, and even when the role of alternative splicing in this type of can...

Breast Cancer (BCa) is a global public health problem in that is one of the main causes of deaths due to cancer in women. Synaptic Vesicle Protein (SV2) is a neuronal protein with three isoforms. Recent research on tumor cells has identified Synaptic Vesicle SV2 receptor isoform A (SV2A) in different types of cancer, such as colon, prostate, and th...

In eukaryotes, genes are frequently interrupted with noncoding sequences named introns. Alternative splicing is a nuclear mechanism by which these introns are removed and flanking coding regions named exons are joined together to generate a message that will be translated in the cytoplasm. This mechanism is catalyzed by a complex machinery known as...

The molecular mechanisms regulating the accuracy of gene expression are still not fully understood. Among these mechanisms, Nonsense-mediated Decay (NMD) is a quality control process that detects post-transcriptionally abnormal transcripts and leads them to degradation. The UPF1 protein lays at the heart of NMD as shown by several structural and fu...

RMS value for the residues involved in the different interactions of UPF1. The residues from H. sapiens and U. maydis used for the calculations are indicated. The crystal handled in each case is included. Relevant residues are highlighted according to their spatial and physicochemical properties (*) or because they have been experimentally demonstr...

Mutations reported for UPF1 that affect different aspects of its functionality. The position in U. maydis and H. sapiens is presented and the conservation between the two sequences is included. The description and effect is summarized for each mutation. (XLSX)

Crystal structures reported for UPF1. Different crystallographic studies have been performed using different portions of UPF1 from H. sapiens and S. cerevisiae. The ID for each crystal and their general characteristics are presented. Some of the structures were used as templates along this work. (XLSX)

RMS values for the amino acids mutated in silico in this work. The position for the different residues in U. maydis is shown. The mutation performed in silico and the atoms considered to calculate the rms value in each case are included. (XLSX)

The precise control of protein production is essential for the appropriate cell physiology and survival. However, single mutations or accidentally introduced errors can occur during the flow of genetic information. In eukaryotic cells, some messenger RNA (mRNA) molecules leave the nucleus after splicing but further mechanisms are involved in the ul...

Se aislaron 76 cepas de aguas residuales provenientes de corredores industriales. Las cepas se sometieron a diferentes condiciones de crecimiento: Temperatura, pH, colorantes y solventes de uso industrial, determinando una diferencia significativa de acuerdo con la prueba T-student al tener afinidad por valores bajos por temperatura a 35°C, por pH...

The accurate expression of the genetic information is regulated by processes like mRNA splicing, proposed after the discoveries of Phil Sharp and Richard Roberts, who demonstrated the existence of intronic sequences, present in almost every structural eukaryotic gene, which should be precisely removed. This intron removal is called “splicing”, whic...

It has been established that a decrease in the population of Gluconacetobacter diazotrophicus associated with sugarcane occurs after nitrogen fertilization. This fact could be due to a direct influence of NH4NO3 on bacterial cells or to changes in plant physiology after fertilizer addition, affecting bacterial establishment. In this work, we observ...

Schizosaccharomyces pombe (Sz. pombe), or fission yeast, is an ascomycete unicellular fungus that has been used as a model system for studying diverse biological processes of higher eukaryotic cells, such as the cell cycle and the maintenance of cell shape, apoptosis, and ageing. Sz. pombe is a rod-shaped cell that grows by apical extension; it div...

Alternative splicing is a co-transcriptional mechanism that regulates eukaryotic gene expression affecting the majority of human genes. In this mechanism, different sequences can be identified and removed from the pre-mRNA. Using alternatives splicing, multiple mRNA combinations of joined sequences can be produced from a single gene, increasing the...

The 3' untranslated region (3'UTR) of human astroviruses (HAstV) consists of two hairpin structures (helix I and II) joined by a linker harboring a conserved PTB/hnRNP1 binding site. The identification and characterization of cellular proteins that interact with the 3'UTR of HAstV-8 virus will help to uncover cellular requirements for viral functio...

The accurate expression of the genetic information is regulated by processes like mRNA splicing, proposed after the discoveries of Phil Sharp and Richard Roberts, who demonstrated the existence of intronic sequences, present in almost every structural eukaryotic gene, which should be precisely removed. This intron removal is called “splicing”, whic...

A pesar de la importancia para el sostenimiento de la vida de nuestro planeta, en el presente desconocemos a la mayor parte de su diversidad. Muchas bacterias son benéficas para la agricultura, la biomedicina, el medio ambiente y la industria. En la actualidad se tiene especial interés en aislar nuevas especies bacterianas, así como en estudiar la...

In an attempt to quantify the number of bacteria present in a high number of samples, routine procedures are usually very time-consuming. During this period of time, bacterial population could be modified. In this work, an alternative for a mas-sive, quick and economic method was evaluated in order to count viable bacteria, consisting in the sealin...

Título en ingles: Quantification of cultivable bacteria by the “Massive Stamping Drop Plate” method Resumen: Cuando se desea cuantificar el número de bacterias presentes en múltiples muestras, los procedimientos de rutina suelen consumir mucho tiempo. En ese periodo las muestras podrían sufrir modificaciones en su población. En el presente trabajo...

A maize rhizosphere isolate was phenotypically and genotypically characterized and identified as Enterobacter spp. bacterium. Germinated seeds were inoculated, the plantlets were sown in vermiculite and in soil and grown under laboratory and field conditions, respectively. The adherence, colonization and plant growth promotion capability of Enterob...

Forty soil samples were collected from four rural communities in the Municipality of Huauchinango (Puebla, Mexico), a region with endemic dermatomycoses. Classical and molecular approaches allowed the identification of 30 different species, including several agents of superficial, subcutaneous and opportunistic mycoses. The most prevalent pathogeni...

Bacteria sustain life on earth, and even thought we only known around 1% of its diversity, several of them could result beneficial when used in different domains, including agriculture, biomedicine, bioremediation, and others. Nowadays, strong effort has been put into elucidating both new bacterial species and the function encoded in their genes; t...

El descubrimiento de la estructura del ácido desoxirribonucleico (ADN) en 1953 y la demostración de que esta molécula constituye la clave de la herencia en los organismos abrió la puerta a numerosas aplicaciones, todas ellas excitantes y prometedoras: desde controlar enfermedades de origen genético hasta modificar la constitución y características...

Proteins of the heterogeneous nuclear ribonucleoparticles (hnRNP) family form a structurally diverse group of RNA binding proteins implicated in various functions in metazoans. Here we discuss recent advances supporting a role for these proteins in precursor-messenger RNA (pre-mRNA) splicing. Heterogeneous nuclear RNP proteins can repress splicing...

hnRNP A/B proteins modulate the alternative splicing of several mammalian and viral pre-mRNAs, and are typically viewed as proteins that enforce the activity of splicing silencers. Here we show that intronic hnRNP A/B-binding sites (ABS) can stimulate the in vitro splicing of pre-mRNAs containing artificially enlarged introns. Stimulation of in vit...

RT-PCR Assay of Splicing Mixtures Incubated with Different Ratios of Test and Control Pre-mRNAs A quantity (80 pM) of test 7-AdA(−.−) or 7-AdA (+.+) pre-mRNA was mixed with various amounts of control 7B-Ad pre-mRNA (from 0 to 40 pM). The mixtures were incubated in HeLa nuclear extracts for 2 h at 30 °C. The RT-PCR assay was carried out with a singl...

Gel-Shift Assay Using Recombinant hnRNP H, F, and A1 The initial G1 and G2 elements (larger letters) stimulated splicing when inserted into a Fugu intron. The sequences immediately flanking the insertion sites are also shown. The 16-nt G1 and 19-nt G2 RNA oligonucleotides were 5′-end labeled and individually incubated with hnRNP proteins (1, 2, and...

The 240-bp alpha exon of the tight junction (TJ) protein ZO-1 pre-mRNA is alternatively spliced. Expression of both ZO-1alpha+/ZO-1alpha- isoforms results in hermetic TJs, and these become leaky when ZO-1alpha- expression prevails. The alpha exon inclusion/skipping mechanism was studied by in vivo RT-PCR splicing assays in neural and epithelial cel...