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Search Results: 1 - 10 of 189888 matches for " Giovan Gómez "
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Variabilidad morfométrica y molecular en poblaciones de Anopheles albimanus (Diptera: Culicidae) de las regiones Caribe y Pacífica de Colombia
Giovan Gómez,Edna Márquez,Margarita Correa
Actualidades Biológicas , 2012,
Abstract:
Factores no biológicos relacionados con el desarrollo de resistencia de Plasmodium falciparum a la cloroquina
GóMEZ GARCíA,GIOVAN FERNANDO; VáSQUEZ VALENCIA,MARíA FERNANDA;
CES Medicina , 2011,
Abstract: the development of plasmodium falciparum resistant to antimalarial drugs constitutes a major public health issue for malaria control. particularly, the emergence and widespread of chloroquine resistant p. falciparum strains in the second half of xx century represents a new challenge to malaria control. the scientific literature has documented factors related to the human host, the vector, the parasite and the treatment, which could explain the selection, survival and local or wide spread of these strains. in this paper are reviewed non-biological factors that could explain the emergency of p. falciparum resistant chloroquine strains. the understanding of these factors is relevant to design strategies to delay the emergence of antimalarial drug resistant parasites.
Análisis morfológico y molecular evidencia problemas al identificar Anopheles nuneztovari (Diptera: Culicidae) por claves dicotómicas Morphological and molecular analyses demonstrate identification problems of Anopheles nuneztovari (Diptera: Culicidae) using dichotomous keys
GIOVAN F GóMEZ,ASTRID V CIENFUEGOS,LINA A GUTIéRREZ,JAN E CONN
Revista Colombiana de Entomología , 2010,
Abstract: El Grupo Oswaldoi, subgénero Nyssorhynchus (Diptera: Culicidae), incluye 16 especies. Algunas de estas especies presentan una alta variabilidad morfológica intraespecífica y similitud interespecie; lo anterior puede ocasionar dificultad en la identificación de la hembra al usar las claves morfológicas, como ocurre con Anopheles nuneztovari, considerado vector primario de malaria en Colombia. En este trabajo se comparó la utilidad de cinco claves morfológicas para la identificación de especímenes A. nuneztovari recolectados en la localidad de Puerto Anchica, Montelibano, Córdoba, Colombia. Se analizaron tres relaciones morfométricas y se confirmó la identificación morfológica utilizando la técnica PCR-RFLP basada en secuencias ITS2. El análisis de 41 hembras usando las claves, mostró que los especímenes A. nuneztovari presentaron sobrelapamiento morfológico con otras especies del Grupo Oswaldoi, como: A. rangeli, A. oswaldoi, A. evansae y A. benarrochi. El análisis molecular confirmó que todos los especímenes corresponden a A. nuneztovari. Dado que el uso de claves morfológicas continúa siendo la estrategia de elección para la identificación de anofelinos, los resultados sugieren que en caso de especies problemáticas, es conveniente confirmar la identificación mediante herramientas moleculares desarrolladas con el respaldo de la identificación de estadios inmaduros. The Oswaldoi Group, subgenus Nyssorhynchus (Diptera: Culicidae), includes 16 species. Some of these species exhibit high intraspecific morphological variability and interspecific similarity; this can lead to difficulty in the identification of females by using morphological keys, as is the case with Anopheles nuneztovari, considered a primary malaria vector in Colombia. In this study we compared the usefulness of five morphological keys for the identification of A. nuneztovari specimens collected in the locality of Puerto Anchica, Montelibano, Córdoba, Colombia. Three morphometric ratios were analyzed and morphological identification results were confirmed using the PCR-RFLP technique based on ITS2 sequences. The analysis of 41 females using the keys showed that A. nuneztovari specimens presented overlap with other species of the Oswaldoi Group, such as A. rangeli, A. oswaldoi, A. evansae and A. benarrochi. Molecular analysis confirmed that all of the specimens corresponded to A. nuneztovari. Because the use of morphological keys continue to be a strategy of choice for the identification of anophelines, the results suggest that in the case of problematic species, it is convenient to confirm i
Análisis morfológico y molecular evidencia problemas al identificar Anopheles nuneztovari (Diptera: Culicidae) por claves dicotómicas
GóMEZ,GIOVAN F; CIENFUEGOS,ASTRID V; GUTIéRREZ,LINA A; CONN,JAN E; CORREA,MARGARITA M;
Revista Colombiana de Entomología , 2010,
Abstract: the oswaldoi group, subgenus nyssorhynchus (diptera: culicidae), includes 16 species. some of these species exhibit high intraspecific morphological variability and interspecific similarity; this can lead to difficulty in the identification of females by using morphological keys, as is the case with anopheles nuneztovari, considered a primary malaria vector in colombia. in this study we compared the usefulness of five morphological keys for the identification of a. nuneztovari specimens collected in the locality of puerto anchica, montelibano, córdoba, colombia. three morphometric ratios were analyzed and morphological identification results were confirmed using the pcr-rflp technique based on its2 sequences. the analysis of 41 females using the keys showed that a. nuneztovari specimens presented overlap with other species of the oswaldoi group, such as a. rangeli, a. oswaldoi, a. evansae and a. benarrochi. molecular analysis confirmed that all of the specimens corresponded to a. nuneztovari. because the use of morphological keys continue to be a strategy of choice for the identification of anophelines, the results suggest that in the case of problematic species, it is convenient to confirm identification using molecular methods developed with the support of the identification of immature stages.
A new mtDNA COI gene lineage closely related to Anopheles janconnae of the Albitarsis complex in the Caribbean region of Colombia
Gutiérrez, Lina A;Orrego, Lina M;Gómez, Giovan F;López, Andrés;Luckhart, Shirley;Conn, Jan E;Correa, Margarita M;
Memórias do Instituto Oswaldo Cruz , 2010, DOI: 10.1590/S0074-02762010000800011
Abstract: an understanding of the taxonomic status and vector distribution of anophelines is crucial in controlling malaria. previous phylogenetic analyses have supported the description of six species of the neotropical malaria vector anopheles (nyssorhynchus) albitarsis s.l. (diptera: culicidae): an. albitarsis, anopheles deaneorum, anopheles marajoara, anopheles oryzalimnetes, anopheles janconnae and an. albitarsis f. to evaluate the taxonomic status of an. albitarsis s.l. mosquitoes collected in various localities in the colombian caribbean region, specimens were analyzed using the complete mitochondrial dna cytochrome oxidase i (coi) gene, the ribosomal dna (rdna) internal transcribed spacer 2 (its2) region and partial nuclear dna white gene sequences. phylogenetic analyses of the coi gene sequences detected a new lineage closely related to an. janconnae in the caribbean region of colombia and determined its position relative to the other members of the complex. however, the its2 and white gene sequences lacked sufficient resolution to support a new lineage closely related to an. janconnae or the an. janconnae clade. the possible involvement of this new lineage in malaria transmission in colombia remains unknown, but its phylogenetic closeness to an. janconnae, which has been implicated in local malaria transmission in brazil, is intriguing.
Species composition and natural infectivity of anthropophilic Anopheles (Diptera: Culicidae) in the states of Córdoba and Antioquia, Northwestern Colombia
Gutiérrez, Lina A;González, John J;Gómez, Giovan F;Castro, Martha I;Rosero, Doris A;Luckhart, Shirley;Conn, Jan E;Correa, Margarita M;
Memórias do Instituto Oswaldo Cruz , 2009, DOI: 10.1590/S0074-02762009000800008
Abstract: malaria is a serious health problem in the states of córdoba and antioquia, northwestern colombia, where 64.4% of total colombian cases were reported in 2007. because little entomological information is available in this region, the aim of this work was to identify the anopheles species composition and natural infectivity of mosquitoes distributed in seven localities with highest malaria transmission. a total of 1,768 anopheles mosquitoes were collected using human landing catches from march 2007-july 2008. ten species were identified; overall, anopheles nuneztovari s.l. was the most widespread (62%) and showed the highest average human biting rates. there were six other species of the nyssorhynchus subgenus: anopheles albimanus (11.6%), anopheles darlingi (9.8%), anopheles braziliensis (6.6%), anopheles triannulatus s.l. (3.5%), anopheles albitarsis s.l. and anopheles oswaldoi s.l. at < 1%; and three of the anopheles subgenus: anopheles punctimacula, anopheles pseudopunctipennis s.l. and anopheles neomaculipalpusat < 1% each. two species from córdoba, an. nuneztovari and an. darlingi, were found to be naturally infected by plasmodium vivax vk247, as determined by elisa and confirmed by nested pcr. all species were active indoors and outdoors. these results provide basic information for targeted vector control strategies in these localities.
Free-energy calculations for semi-flexible macromolecules: Applications to DNA knotting and looping
Stefan M. Giovan,Robert G. Scharein,Andreas Hanke,Stephen D. Levene
Quantitative Biology , 2014, DOI: 10.1063/1.4900657
Abstract: We present a method to obtain numerically accurate values of configurational free energies of semiflexible macromolecular systems, based on the technique of thermodynamic integration combined with normal-mode analysis of a reference system subject to harmonic constraints. Compared with previous free-energy calculations that depend on a reference state, our approach introduces two innovations, namely the use of internal coordinates to constrain the reference states and the ability to freely select these reference states. As a consequence, it is possible to explore systems that undergo substantially larger fluctuations than those considered in previous calculations, including semiflexible biopolymers having arbitrary ratios of contour length L to persistence length P. To validate the method, high accuracy is demonstrated for free energies of prime DNA knots with L/P=20 and L/P=40, corresponding to DNA lengths of 3000 and 6000 base pairs, respectively. We then apply the method to study the free-energy landscape for a model of a synaptic nucleoprotein complex containing a pair of looped domains, revealing a bifurcation in the location of optimal synapse (crossover) sites. This transition is relevant to target-site selection by DNA-binding proteins that occupy multiple DNA sites separated by large linear distances along the genome, a problem that arises naturally in gene regulation, DNA recombination, and the action of type-II topoisomerases.
Into the life and death: RecA a WISE factor working to integrate survival and evolution in Escherichia coli  [PDF]
José María Gómez Gómez
Advances in Bioscience and Biotechnology (ABB) , 2013, DOI: 10.4236/abb.2013.43A059
Abstract:

Escherichia coli RecA has been considered traditionally a cellular protein with multiple vital functions working to ensure the maintenance of integrity of genome in each individual bacterial cell as well as promoting swarming migration in collectivity. On the contrary, recently it has been described that RecA promotes cellular apoptotic-like death (ALD), a pathway of programmed cellular death (PCD). In fact, RecA has been dubbed as the major apoptotic executor in E. coli. From these studies, RecA emerges as a prototypical Gin/Gan protein that despite of their intrinsic vital and lethal anfi-funcionality becomes in a WISE factor: a Worker to Integrate Survival and Evolution in E. coli evolving populations living in community. Here, I provide a review of recent experimental and conceptual advances trying to understand these RecA’s antagonistic roles in appearance contradictory under a unified biological vision.

Equilibrium Dynamics in the Neoclassical Growth Model with Habit Formation and Elastic Labor Supply  [PDF]
Manuel A. Gómez
Theoretical Economics Letters (TEL) , 2012, DOI: 10.4236/tel.2012.25087
Abstract: This note analyzes the equilibrium dynamics in the neoclassical growth model with habit-forming preferences and elastic labor supply. Habits enter into utility in a multiplicative way. The specification of the habit formation process comprises the particular cases of internal and external habits. Existence, uniqueness and saddle-path stability of the steady state are proved analytically.
A Novel Cellular Autoaggregative Developmentally CRP Regulated Behaviour Generates Massively Chondrule-Like Formations over Surface of Old Escherichia coli K-12 Macrocolony Biofilms  [PDF]
José María Gómez Gómez, Ricardo Amils
Advances in Bioscience and Biotechnology (ABB) , 2014, DOI: 10.4236/abb.2014.59086
Abstract:

How Escherichia coli bacteria develop a particular colonial, 3-D biofilm morphological pattern is still a poorly understood process. Recently, we reported a new E. coli K-12 morphotype exhibited by old macrocolonies described as volcano-like. The formative developmental process of this morphotype has been presented as a suitable experimental model for the study of 3D patterning in macrocolony biofilms. Here, we report the optical microscopy observations and genetic analysis that have unveiled the existence of a novel autoaggregative behaviour which generates massive lumpiness over the surface of the volcano-like macrocolonies. These lumpy formations are generated by the autoaggregation and strong interaction of tightly packed bacterial cells in structures with a chondrule-like appearance which give the colony’s surface its characteristic microscopic lumpy phenotype. Furthermore, they exhibit different levels of maturation from the edge to the center of the colony. Hence, its generation appears to follow a spatiotemporal program of development during the macrocolony’s morphogenesis. Interestingly, the agar’s hardness influences the morphology exhibited by these formations, with high agar concentration (1.5%, 15 g/L) suppressing its development. This new auto-aggregative E. coli’s behaviour does not require the activity of the biofilm master regulator CsgD, the adhesiveness of flagella, pili type 1, adhesin Ag43, β-1,6-N-acetyl-D-glucosamine polymer-PGA, cellulose or colanic acid, but it is under glucose repression and the control of cAMP receptor protein (CRP). The possible physiological role

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