Nelson Rivera-Franco

In specific altitude ranges, biotic and abiotic factors can impact vector mosquitoes’ adaptation capacity, affecting their population differentiation. This study analyses if there exist morphological and genetic differences in four Anopheles (Kerteszia) populations in specific altitude ranges from the Colombian pacific coast to the premontane humid forests in Valle del Cauca, Colombia. Likewise, it is compared if the vector mosquito groups analyzed were genetically similar to the ones available in the region. Traditional and geometric morphometric analysis and the molecular marker CO-I were used. The research found that vector mosquitoes’ littoral populations differentiated morphologically according to their cross veins wing shapes compared to the other three groups in higher altitudes. Their genetic distances fluctuate between 4.95% and 6.84%, indicating that vector mosquitoes’ littoral populations belong to Anopheles neivai s.s. while the ones of higher altitudes are related to An. neivai 8—a lineage previously proposed based solely on molecular data. The study concludes that vector mosquitoes at the pacific Colombian coast from the littoral area in lower altitudes maintain a vast genetic variability with uniform populations; however, in higher altitudes, vector mosquitoes acquire molecular and morphological differences that may include the settlement of other lineages.

In Cali, Colombia, 405,689 COVID-19 cases were reported until March 2023, with 2463 complete genome sequences available for analysis. SARS-CoV-2 genomic data from Cali were analyzed to determine the prevalence of variants as well as the mutation frequencies. This study identified Nextstrain clades, Pango lineages, and specific mutations in key viral proteins. A total of 23 Nextstrain clades and 118 Pango lineages were detected, including variants of interest (Lambda, Mu) and variants of concern (Alpha, Gamma, Delta, Omicron). Analysis identified 2424 missense mutations, with notable frequencies in NSP3 (465), S (367), NSP2 (205), N (180), ORF3a (144), NSP12b (113), and NSP13 (108). The study also observed a high prevalence of simultaneous transmission of multiple variants. The COVID-19 epidemic waves in Cali were shaped more by social and economic dynamics than by the emergence of specific SARS-CoV-2 variants. These findings highlight the importance of context-specific public health interventions to mitigate future outbreaks effectively.

The oral microbiome, particularly periodontopathogens, may influence the gut microbiome. The aim of this study was to assess the correspondence, diversity, and abundance of periodontopathogenic bacteria in oral and fecal samples from healthy adults. Secondary analyses of 12 public sequences from 6 healthy women, matched by anatomical site (gut and oral cavity), were performed using 16S rRNA-based metagenomics. The sequences were obtained from the BioProject PRJNA834584, published by the Chinese University of Hong Kong, with data generated via Illumina MiSeq. The Shaman application, which relies on Vsearch and DESeq2 for R, along with the Silva database, facilitated the determination of differential abundance and diversity at the species and genus levels between anatomical sites. After dereplication and removal of singletons and chimeras, 352 OTUs were identified. Taxonomic assignment resulted in 148 genera and 80 species, corresponding to 88.64% and 25.85% of annotations, respectively. The dendrogram displayed two distinct clusters separating oral and faecal samples, and principal coordinate analysis accounted for 53.7% of the variance by anatomical site (Permanova test, p=0.003). The Shannon diversity index was 2.14 (95% CI: 1.55-2.73) for fecal samples and 2.28 (2.03-2.53) for oral samples. The Simpson index was 0.70 (0.53-0.88) for faecal samples and 0.82 (0.76-0.88) for oral samples. Periodontopathogenic bacteria were found exclusively in oral samples, with variations in frequency. No periodontopathogenic species were detected in fecal samples. The human microbiome from two different niches in healthy adults shows distinct bacterial compositions between the oral cavity and the gut, with Bacteroides predominating in faecal samples and Streptococcus in oral samples. Greater richness was observed in faecal samples. Both microbiomes exhibited high bacterial diversity, with no significant differences.

Este artículo explora la influencia de las cordilleras sobre el flujo génico de Exaerete smaragdina, una abeja de amplia distribución en Colombia y de gran importancia en el sostenimiento de la diversidad florística de sistemas naturales, gracias a su función como agente polinizador de orquídeas neotropicales. Se muestrearon once bosques naturales conservados. En cada bosque se establecieron dos transectos de 250 m x 2,5 m. A lo largo de cada transecto, se ubicaron seis estaciones de muestreo cada 50 metros, en las cuales se instalaron trampas de olor con atrayentes aromáticos. El material biológico recolectado fue procesado en el Laboratorio de Entomología de la Universidad del Cauca y las abejas depositadas en la Colección de Referencia del Museo de Historia Natural. Se realizó la caracterización molecular mediante el gen COI. Los resultados soportan la idea de que E. smaragdina es un complejo de especies en el país. La estructura genética y la alta diferenciación molecular entre las poblaciones dispuestas en cada flanco de las cordilleras sugiere su aparición como un evento geográfico que posiblemente aisló las poblaciones, donde los requerimientos ecológicos locales han constituido una barrera influyente en el aislamiento reproductivo de la especie.

Despite advances in chemotherapeutic drugs used against cervical cancer, available chemotherapy treatments adversely affect the patient’s quality of life. For this reason, new molecules from natural sources with antitumor potential and few side effects are required. In previous research, Pllans−II, a phospholipase A₂ type-Asp49 from Porthidium lansbergii lansbergii snake venom, has shown selective attack against the HeLa and Ca Ski cervical cancer cell lines. This work suggests that the cytotoxic effect generated by Pllans−II on HeLa cells is triggered without affecting the integrity of the cytoplasmic membrane or depolarizing the mitochondrial membranes. The results allow us to establish that cell death in HeLa is related to the junction blockage between α₅β₁ integrins and fibronectin of the extracellular matrix. Pllans−II reduces the cells’ ability of adhesion and affects survival and proliferation pathways mediated by intracellular communication with the external environment. Our findings confirmed Pllans−II as a potential prototype for developing a selective chemotherapeutic drug against cervical cancer.

Due to the lack of chemotherapeutic drugs that selectively affect cervical cancer cells, natural sources such as snake venom are currently being investigated for molecules with antitumor potential. Pllans–II, a phospholipase A₂ type–Asp49 from Porthidium lansbergii lansbergii snake venom, induced cell death in a cervical cancer cell line—Ca Ski—related to dysfunction in the ability to resolve endoplasmic reticulum stress, evidenced by sub–expression of genes such as PERK, ERO1 PDIs, HSP70, and CHOP. Western blot analysis validated the last two genes′ sub–expression at the protein level. In addition, Pllans–II presented a dose–dependent cytotoxic effect on cancer cells and an insignificant effect on healthy endothelial cells (HUVEC). Additionally, Pllans–II inhibited cancer cells′ adhesion and migration capacity, induced cell cycle arrest in the G2/M phase, and induced apoptosis stimulated possibly by the extrinsic route. These results demonstrate for the first time that Pllans–II has an antitumor effect on a squamous epithelial cervical cancer cell line and represents a possible biotechnological tool for designing a prominent antitumor agent.

Objetivo: Identificar las variantes patogénicas en una familia raizal afrocolombiana con factores de riesgo para el glaucoma. Métodos: En el presente estudio, se realizó una secuenciación de exoma completo en siete miembros de una familia Raizal del archipiélago de San Andrés, Providencia y Santa Catalina del Caribe colombiano. La mitad de ellos habían sido diagnosticados con glaucoma. Además, se incluyeron dos voluntarios sanos de la isla. Resultados: De las 198 variantes de un solo nucleótido (SNV) asociadas con el glaucoma, previamente informadas por la base de datos DisGeNET, se identificaron cuatro en los miembros de la familia Raizal: rs11938093, rs7336216, rs3817672 y rs983034. Además, en todos los miembros de la familia, pero no en voluntarios sanos, se identificó SNV rs983034 en el gen mediador de secreción de ligando Wnt (WLS). Notablemente, las disfunciones WLS se han relacionado con patologías en la red trabecular (TM) del ojo. TM es un regulador importante del flujo de salida del humor acuoso que mantiene la presión intraocular (presión intraocular) en niveles normales. El daño a la TM se asocia con hipertensión ocular que conduce a la progresión del glaucoma. En relación con los demás SNV identificados, se constató su presencia en algunos miembros de la familia Raizal. Sin embargo, aún no está clara la causa fisiopatológica que asocia estas SNV con el glaucoma. Conclusiones: Fue posible identificar cuatro SNVs no sinónimos con predicción de daño significativo en la estructura y función de genes asociados a patología de glaucoma en un afrocolombiano.

Deep-sea sediments are considered an extreme environment due to high atmospheric pressure and low temperatures, harboring novel microorganisms. To explore marine bacterial diversity in the southern Colombian Caribbean Sea, this study used 16S ribosomal RNA (rRNA) gene sequencing to estimate bacterial composition and diversity of six samples collected at different depths (1681 to 2409 m) in two localities (CCS_A and CCS_B). We found 1842 operational taxonomic units (OTUs) assigned to bacteria. The most abundant phylum was Proteobacteria (54.74%), followed by Bacteroidetes (24.36%) and Firmicutes (9.48%). Actinobacteria and Chloroflexi were also identified, but their dominance varied between samples. At the class-level, Alphaproteobacteria was most abundant (28.4%), followed by Gammaproteobacteria (24.44%) and Flavobacteria (16.97%). The results demonstrated that some bacteria were common to all sample sites, whereas other bacteria were unique to specific samples. The dominant species was Erythrobacter citreus, followed by Gramella sp. Overall, we found that, in deeper marine sediments (e.g., locality CCS_B), the bacterial alpha diversity decreased while the dominance of several genera increased; moreover, for locality CCS_A, our results suggest that the bacterial diversity could be associated with total organic carbon content. We conclude that physicochemical properties (e.g., organic matter content) create a unique environment and play an important role in shaping bacterial communities and their diversity.