Laura L. Valdez-Velazquez

Mass Fingerprinting of the Venom and Transcriptome of Venom Gland of Scorpion Centruroides tecomanus

Centruroides tecomanus is a Mexican scorpion endemic of the State of Colima, that causes human fatalities. This communication describes a proteome analysis obtained from milked venom and a transcriptome analysis from a cDNA library constructed from two pairs of venom glands of this scorpion. High perfomance liquid chromatography separation of soluble venom produced 80 fractions, from which at least 104 individual components were identified by mass spectrometry analysis, showing to contain molecular masses from 259 to 44,392 Da. Most of these components are within the expected molecular masses for Na+- and K+-channel specific toxic peptides, supporting the clinical findings of intoxication, when humans are stung by this scorpion. From the cDNA library 162 clones were randomly chosen, from which 130 sequences of good quality were identified and were clustered in 28 contigs containing, each, two or more expressed sequence tags (EST) and 49 singlets with only one EST. Deduced amino acid sequence analysis from 53% of the total ESTs showed that 81% (24 sequences) are similar to known toxic peptides that affect Na+-channel activity, and 19% (7 unique sequences) are similar to K+-channel especific toxins. Out of the 31 sequences, at least 8 peptides were confirmed by direct Edman degradation, using components isolated directly from the venom. The remaining 19%, 4%, 4%, 15% and 5% of the ESTs correspond respectively to proteins involved in cellular processes, antimicrobial peptides, venom components, proteins without defined function and sequences without similarity in databases. Among the cloned genes are those similar to metalloproteinases.

Transcriptome Analysis of Scorpion Species Belonging to the Vaejovis Genus

Scorpions belonging to the Buthidae family have traditionally drawn much of the biochemist’s attention due to the strong toxicity of their venoms. Scorpions not toxic to mammals, however, also have complex venoms. They have been shown to be an important source of bioactive peptides, some of them identified as potential drug candidates for the treatment of several emerging diseases and conditions. It is therefore important to characterize the large diversity of components found in the non-Buthidae venoms. As a contribution to this goal, this manuscript reports the construction and characterization of cDNA libraries from four scorpion species belonging to the Vaejovis genus of the Vaejovidae family: Vaejovis mexicanus, V. intrepidus, V. subcristatus and V. punctatus. Some sequences coding for channel-acting toxins were found, as expected, but the main transcribed genes in the glands actively producing venom were those coding for non disulfide-bridged peptides. The ESTs coding for putative channel-acting toxins, corresponded to sodium channel β toxins, to members of the potassium channel-acting α or κ families, and to calcium channel-acting toxins of the calcin family. Transcripts for scorpine-like peptides of two different lengths were found, with some of the species coding for the two kinds. One sequence coding for La1-like peptides, of yet unknown function, was found for each species. Finally, the most abundant transcripts corresponded to peptides belonging to the long chain multifunctional NDBP-2 family and to the short antimicrobials of the NDBP-4 family. This apparent venom composition is in correspondence with the data obtained to date for other non-Buthidae species. Our study constitutes the first approach to the characterization of the venom gland transcriptome for scorpion species belonging to the Vaejovidae family.

Renin gene haplotype diversity and linkage disequilibrium in two Mexican and one German population samples

Introduction. Renin is the main rate-limiting enzyme in the renin—angiotensin—aldosterone system. Its gene, REN, is a candidate crucial factor in essential hypertension and cardiovascular disease. The aim of this study was to evaluate allele and haplotype distributions of REN polymorphisms, and to estimate normalised linkage disequilibrium (D’) in Mexican and German populations. Materials and methods. Four groups were studied for the REN single nucleotide polymorphisms (SNPs) 1205C>T, 1303G>A, and 10607G>A, in population samples of Mexican Mestizo (n = 86), Mexican Huichol (n = 49), German (n = 39), and individuals with hypertension diagnosis (n = 66). Polymorphisms were detected by PCR—RFLP. Genotype, allele and haplotype frequencies were estimated. Results. SNP 1205C>T and 10607G>A allele and genotype distribution showed inter-group differences. The 1205T and 10607A allele showed a significance difference in hypertensive population. Haplotype analysis also showed some inter-group differences, especially in 1205C-1303G-10607G, 1205C-1303G-10607A and 1205T-1303G-10607G haplotypes. The segregation analysis disclosed complete linkage disequilibrium between 1205 and 1303 loci. Conclusion. These results provide an example of genetic diversity in related populations and illustrate the convenience of increasing the number of loci in associative studies between diseases and candidate genes.

Polymorphisms in the Genes Related to Angiogenesis Are Associated With Uterine Cervical Cancer

Introduction The expression of plasminogen activator inhibitor type 1 (PAI-1), vascular endothelial growth factor (VEGF), and transforming growth factor β1 (TGF-β1) participates in the angiogenesis of several cancer types. The goal of this study was to investigate polymorphisms in genes related to angiogenesis (PAI-1-675 4G/5G, VEGF C936T, and TGF-β1 G-800A) to evaluate the risk for developing uterine cervical cancer (UCC). Methods In a case-control study, 100 healthy subjects and 100 patients with UCC from Mexico were included. We determined the genetic profile of the polymorphic markers, which were evaluated by polymerase chain reaction using a sequence-specific primer. Results There was no statistical difference in the allele distribution from the intergroup comparisons of PAI-1 675 4G/5G and VEGF C936T data; however, a significant difference was observed within TGF-β1 G-800A. The linkage disequilibrium analysis revealed that PAI-1 -675 4G and TGF-β1 -800A pair-haplotype was in strong linkage disequilibrium with a significantly increased risk (odds ratio, 3.44; 95% confidence interval, 1.66–7.25) to UCC. Conclusions The polymorphisms in the genes related to angiogenesis -675 4G/5G PAI-1 and G-800A TGF-β1, segregated solely or combined, might contribute to the increased susceptibility to UCC in a Mexican population.

Association of the polymorphism 12109g>A from the REN gene as a risk factor for preterm birth

Introduction: Preterm birth is the most important cause of neonatal mortality and morbidity. It is a multifactorial disease with different etiologies, including genetic factors. Genetic variability is represented by single nucleotide polymorphisms (SNPs) in genes of proteins involved in the contractile activity. We determine the association between SNP 12109G> A in REN associated with preterm birth and premature rupture of membrane. Materials and methods: A study of cases (N=112, 22–36 weeks of gestation; mean: 31, 95% confidence interval 30.7–32.2) and controls (N=66; 38–40 weeks of gestation from the last menstrual period; mean: 39.8, 95% confidence interval 38.9–39.4) was performed. Genomic DNA was isolated in all patients from peripheral blood. The SNP 12109G> A (Mbo I) in REN was typified by PCR-restriction fragment length polymorphism. Results: A significant difference in the case group for the SNP 12109G>A was observed. The A allele was increased in women with preterm birth (81% cases vs. 15% control, p<0.0000004). There was also a significant difference between genotypes, mainly an excess of G/A heterozygotes in women with preterm birth (60% cases vs. 23% controls). The phenotype 12109G> A has odds ratio 6.62 (95% confidence interval 3.14–14.15), which means a high risk of preterm birth/premature rupture of membrane in presence of allele A, both in homozygotes and in heterozygotes. Conclusion: Allelic frequency of A of SNP 12109G>A was higher in women with preterm birth than in women with normal vaginal delivery and could be considered a risk factor.

Estudio de usabilidad de visualización molecular educativa en un teléfono inteligente

Chemistry students have difficulty understanding molecular structures and their functions. To aide their comprehension, molecular visualization software has been developed to run on smart phones, but in order to positively influence learning it must have a high degree of usability (usability measures how software is used in terms of efficiency, efficacy and satisfaction). This paper describes a usability study of molecular visualization software running on a smart phone, where chemistry students analyzed molecular models. Results showed very good usability and 95% of students wanted to use it in further classes.

Description of Pseudo-nitzschia cuspidata var. manzanillensis var. nov. (Bacillariophyceae): morphology and molecular characterization of a variety from the central Mexican pacific

The diatoms of the genus Pseudo-nitzschia are of special interest due to their capacity to produce domoic acid, which is responsible for amnesic shellfish poisoning (ASP) in humans. Domoic acid is a neurotoxin that can cause devastating effects in the food web, especially in seabirds and marine mammals. Identification of Pseudo-nitzschia species is challenging since the morphological differences are difficult to distinguish in the light microscope, and even in SEM or TEM. In recent years, new molecular biology methods have been developed that allow us to differentiate between pseudo-cryptic or cryptic species. In this study, a new pseudo-cryptic taxon is described within the Pseudo-nitzschia/pseudodelicatissima complex, as a variety of P. cuspidata. Subtle morphological differences were found among our strains of P. cuspidata and other previously described strains of the P. pseudodelicatissima/cuspidata complex with respect to the poroids of the valvocopula. These differences were supported by phylogenetic analyses of ITS rDNA sequences. The existence of hemi-compensatory base changes in some of the strains indicates the presence of a separate clade, which is described as a new variety of P. cuspidata group. Domoic acid was not detected in the strains investigated in this study.

Polimorfismo rs4285184 del gen MGAT1 como factor de riesgo de obesidad en la población mexicana

BACKGROUND AND OBJECTIVE Obesity is a factor that contributes to the morbidity of certain diseases and to worldwide mortality. MGAT1 is a glycosyltransferase involved in the synthesis of protein-bound and lipid-bound oligosaccharides and its polymorphisms are possibly involved in the etiology of obesity. We investigated the association of the rs4285184 polymorphism of the MGAT1 gene with obesity in adults in the State of Colima, Mexico. METHODS A case-control study was conducted that included 244 subjects. All of them were grouped according to their percentage of body fat, determined through bioelectrical impedance, and they were genotyped for the rs4285184 polymorphism of the MGAT1 gene through PCR-RFLP. The results were analyzed for their association with the percentage of body fat. RESULTS The G allele had a frequency of 49.19 and 38.75% for the cases and controls, respectively (P=.020) (OR 1.53; 95% CI 1.068-2.193). The frequency of the A/G+G/G genotype was 75% in the obese patients, which was significantly higher compared with the 57.5% of the control group (P=.004) (OR 2.217; 95% CI 1.287-3.821). CONCLUSIONS The presence of the rs4285184 polymorphism of the MGAT1 gene increased the risk for developing body fat associated with obesity in the Mexican population.

Histological changes caused by meclofenamic acid in androgen-independent prostate cancer tumors: evaluation in a mouse model.

ABSTRACT Meclofenamic acid is a nonsteroidal anti-inflammatory drug that has shown therapeutic potential for different types of cancers, including androgen-independent prostate neoplasms. The antitumor effect of diverse nonsteroidal anti-inflammatory drugs has been shown to be accompanied by histological and molecular changes that are responsible for this beneficial effect. The objective of the present work was to analyze the histological changes caused by meclofenamic acid in androgen-independent prostate cancer. Tumors were created in a nude mouse model using PC3 cancerous human cells. Meclofenamic acid (10 mg/kg/day; experimental group, n=5) or saline solution (control group, n=5) was administered intraperitoneally for twenty days. Histological analysis was then carried out on the tumors, describing changes in the cellular architecture, fibrosis, and quantification of cellular proliferation and tumor vasculature. Meclofenamic acid causes histological changes that indicate less tumor aggression (less hypercellularity, fewer atypical mitoses, and fewer nuclear polymorphisms), an increase in fibrosis, and reduced cellular proliferation and tumor vascularity. Further studies are needed to evaluate the molecular changes that cause the beneficial and therapeutic effects of meclofenamic acid in androgen-independent prostate cancer.