Prochilodus magdalenaeis a freshwater fish endemic to the Colombian Magdalena-Cauca and Caribbean hydrographic basins. The genetic structure patterns of populations of different members ofProchilodusand the historic restocking of its depleted natural populations suggest thatP. magdalenaeexhibits genetic stocks that coexist and co-migrate throughout the rivers Magdalena, Cauca, Cesar, Sinú and Atrato. To test this hypothesis and explore the levels of genetic diversity and population demography of 725 samples ofP.magdalenaefrom the studied rivers, we developed a set of 11 species-specific microsatellite loci using next-generation sequencing, bioinformatics, and experimental tests of the levels of diversity of the microsatellite loci. The results evidenced thatP. magdalenaeexhibits high genetic diversity, significant inbreeding coefficient ranging from 0.162 to 0.202, and signs of erosion of the genetic pool. Additionally, the population genetic structure constitutes a mixture of genetic stocks heterogeneously distributed along the studied rivers, and moreover, a highly divergent genetic stock was detected in Chucurí, Puerto Berrío and Palagua that may result from restocking practices. This study provides molecular tools and a wide framework regarding the genetic diversity and structure ofP. magdalenae, which is crucial to complement its baseline information, diagnosis and monitoring of populations, and to support the implementation of adequate regulation, management, and conservation policies.

The tiger shrimp Penaeus monodon is a native species of the Indo-Pacific Ocean that was introduced to promote its cultivation in several American countries, including Colombia. As a result of inappropriate aquaculture practices, it has established itself in the wild in almost all the Colombian Caribbean Sea. To evaluate the genetic diversity, population structure, and origin of the founder populations, samples from three sites in the Colombian Caribbean were analyzed from 10 microsatellite loci and the mitochondrial DNA Control Region. Genetic diversity similar to native populations was found to be present in three relatively discrete populations and their origin is related to natural populations from Thailand, the Philippines, Taiwan and China. We discuss how oceanographic conditions and culture systems of tiger shrimp facilitated the success of biological invasion processes in marine ecosystems of the Colombian Caribbean.

The comparative phylogeography of marine species with contrasting dispersal potential across the southern Caribbean Sea was evaluated by the presence of two putative barriers: the Magdalena River plume (MRP) and the combination of the absence of a rocky bottom and the almost permanent upwelling in the La Guajira Peninsula (ARB + PUG). Three species with varying biological and ecological characteristics (i.e., dispersal potentials) that inhabit shallow rocky bottoms were selected: Cittarium pica (PLD < 6 days), Acanthemblemaria rivasi (PLD < 22 days), and Nerita tessellata (PLD > 60 days). We generated a set of SNPs for the three species using the ddRad-seq technique. Samples of each species were collected in five locations from Capurganá to La Guajira. For the first time, evidence of a phylogeographic break caused by the MRP is provided, mainly for A. rivasi (AMOVA: Φ_CT = 0.420). The ARB + PUG barrier causes another break for A. rivasi (Φ_CT = 0.406) and C. pica (Φ_CT = 0.224). Three populations (K = 3) were identified for A. rivasi and C. pica, while N. tessellata presented one population (K = 1). The Mantel correlogram indicated that A. rivasi and C. pica fit the hierarchical population model, and only the A. rivasi and C. pica comparisons showed phylogeographic congruence. Our results demonstrate how the biological traits of these three species and the biogeographic barriers have influenced their phylogeographic structure.

El río Magdalena es una de las cuencas más importantes de Colombia, cuenta con gran cantidad de especies de peces importantes para la economía de muchas comunidades en el país. Sin embargo, una reducción marcada en las poblaciones de distintas especies asociadas se ha presentado por diferentes factores. Dentro de estos, se destaca la construcción de la represa de Betania, como respuesta a los requerimientos energéticos en Colombia. No obstante, especies migratorias como Prochilodus magdalenae, de importancia económica para la pesquería artesanal, se han visto seriamente afectadas, por lo que se ha generado la necesidad de analizar su estructura y diversidad genética, teniendo en cuenta la construcción de la represa como posible factor de fragmentación. Para esto, se hace adecuado el uso de microsatélites como marcador molecular en diferentes localidades de estudio aguas arriba y abajo de la represa. Esto permitió evaluar en 171 individuos el estado de la diversidad genética, cómo se encuentra distribuida esta variabilidad en las localidades de estudio y cómo influyen algunos factores como la construcción de la represa sobre su estructura genética. En este sentido, se obtuvieron 111 alelos distribuidos en siete loci 100 % polimórficos. Los promedios generales para la heterocigosidad observada fueron de 0,2169, mientras que para las esperadas fueron de 0,8316. Los estadísticos de Fst y PhiPT mostraron que existe una moderada diferenciación entre la represa de Betania y todas las localidades muestreadas. El análisis de inferencia bayesiana detectó la coexistencia de tres poblaciones en la cuenca del río, entre las que destaca la de Betania. Estos resultados se pueden estar presentando, debido a la fragmentación que genera la represa en el río, impidiendo el flujo genético entre las localidades aguas arriba y aguas abajo de la represa

Pneumonia caused by Pneumocystis jirovecii poses a serious threat, particularly to immunocompromised patients such as those with HIV/AIDS, transplant recipients, or individuals undergoing chemotherapy. Its diagnosis is challenging because current methods, such as microscopy and certain molecular tests, have limitations in sensitivity and specificity, and require specialized equipment, which delays treatment initiation. In this context, CRISPR-Cas12-based methods offer a promising alternative: they are rapid, highly specific, sensitive, and low-cost, enabling more timely and accessible detection, even in resource-limited settings. We developed a simple and rapid detection platform based on the CRISPR-Cas12 coupled with lateral flow strips. A guide RNA was designed against DHPS, β-tubulin, and mtLSU rRNA genes. The guide corresponding to β-tubulin showed high sensitivity in the detection of P. jirovecii to produce a detectable fluorescence signal within the first 20–30 min. In addition, it demonstrated high specificity for P. jirovecii when DNA from other microorganisms was used. When coupled with lateral flow strips, high sensitivity and specificity were also observed for detecting positive samples, without the need for genetic amplification. CRISPR-Cas12 successfully detected P. jirovecii infection in an initial diagnostic application, demonstrating the potential of this method for integration into public health diagnostic systems, particularly in field, due to its adaptability, speed, and ease of use.

Se evaluaron algunos aspectos poblacionales de Cittarium pica y su relación con variables ambientales y características de cobertura del sustrato en litorales rocosos en 3 estaciones (Bahía Concha = B.C, Bonito Gordo = B.G y Taganga = TAG) en Santa Marta, Magdalena, Colombia. El área de estudio presentó una abundancia de 3,821 individuos y una densidad de 2.65 (± 4.76) Ind/m2. Se estimó que cada individuo aporta 0.0482 g/Ind de biomasa al siguiente nivel trófico, para un total de 0.1279 g/m2. En el área de estudio predominaron los individuos de tallaspequeñas (98.09%), seguido por tallas medianas (1.83%) y por último tallas grandes (0.08%). Al tener en cuenta los individuos recapturados, se observó que la población de C. pica se comporta como una población abierta. Los parámetros de crecimiento de Von Bertalanffy estimaron una longitud asintótica (L∞) de 94.14 mm y un coeficiente de crecimiento (K) de 0.32/año, mientras el crecimiento observado fue de 0.1094 mm/día. Se estimó una tasa de mortalidad total (Z) de 1.71/año y una tasa de explotación (E) de 0.65. Se demostró una fuerte sobreexplotación deC. pica en los litorales rocosos de Santa Marta, Colombia.