Revista Colombiana de Biotecnología

5-6

Authors: Gustavo Buitrago Hurtado

Intellectual property and the sustainable use of natural resources and biodiversity

17-23

Authors: Romina Belén Parada, Emilio Rogelio Marguet, Marisol Vallejo

Two hundred and thirty four actinobacteria strains were isolated from Argentinian and Peruvian soil in order to evaluate the antimicrobial activity against multidrug resistant bacteria On the basis of their antagonist activity against methicillin-resistant Staphylococcus aureus (MRSA) and two vancomycin-resistant Enterococcus (EVR-Van A and EVR Van B),13 strains were selected. The presence of NRPS, PKS-I and PKS-II genes were also investigated by PCR techniques. Among the 13 selected actinobacteria, strain AC69C displayed the higher activity in diffusion tests in solid medium and was further evaluated for the production of antagonist metabolites in liquid media. The best results were obtained using fermentation broth with carbohydrates, when starch and glucose were used in combination. Antimicrobial activities of 640 arbitrary units (AU), 320 AU, 320 AU and 80 AU were obtained against EVR-Van A, EVR-Van B, Listeria monocytogenes ATCC7644 and MRSA, respectively. PCR amplification of 16S rRNA gene and subsequent phylogenetic analysis of AC69C strain displayed a 100 % homology with Streptomyces antibioticus NRRL B-1701. It was not possible to establish a correlation between the amplified genes and antimicrobial activity of the 13 selected strains. The results of this work show the wide distribution of actinobacteria in soil and the importance of the isolation of strain to screen novel active metabolites against multidrug resistant bacteria of clinical origin.

35-46

Authors: Jazmín Vanessa Pérez-Pazos, Diana Beatriz Sánchez-López

The use of plant growth promoting Rhizobacteria (PGPR) is an alternative to replace chemical fertilizers for the cultivation of agricultural crops. The aim of this research was to search, selection and characterization of PGPR from the genus Azotobacter, Azospirillum and Pseudomonas natives from sweet potato (Ipomoea batatas) plants and rhizosphere of representative production regions of the Colombian Caribbean. Selected isolates were identified by molecular methods and they were screened in vitro for activities related to plant growth such as phosphate solubilization, indole production and acetylene reduction. The strains were tested in the greenhouse on plants of Ipomoea batatas produced in vitro. The height, root length, dry mass of the shot and root were evaluated. Associated with sweet potato crop us finded strains identificated as Azotobacter vinelandii, Azotobacter chroococcum, Azospirillum lipoferum, Azospirillum brasilense and Pseudomonas denitrificans. The strains were able to solubilize phosphate, synthesize indole-3-acetic acid (IAA) and reduce acetylene. The inoculation of bacteria selected increased growth parameters such as root length, height, dry weight root and shoot in plants of sweet potato in greenhouse. Those results catalog to the isolated obtained as possible microorganisms with potential as biofertilizers in sweet potato.

63-73

Authors: Melangel Tacoronte, María Vielma A., Auxiliadora Olivo, Nancy Chacín

The recovery of native potato varieties is a current priority in Venezuela, given their value as a genetic resource of high nutritional quality. Unfortunately, native potato varieties were progressively replaced by exotic commercial, varieties. To date, the limited existing germplasm of native potato varieties is impoverished and of low quality, due to its continual reutilization in crop cycles. Nevertheless, efforts can be made to recover and standardize the production of quality propagules under adequate sanitary conditions. The aim of this study was to assay the effect of varying concentrations of nitrates and saccharose in tissue culture media of three Venezuelan varieties "Cucuba", "Arbolona Negra" and "Rosada". Unimodal segments were planted and incubated using a photoperiod of 16 h light (76 μmol photon m-2 s-1) at 19 ± 1 ºC. The experiment was designed following a standard factor analysis, consisting of three treatments, parting from the basic Murashige & Skoog (MS) medium and data were submitted to an multifactor ANOVA. Our findings indicate significant statistical differences amongst all of the treatments assayed, confirming that all of the varieties reached maximum physiological response under increasing concentrations of nitrates. Such was the case with 1.98 g L-1 ammonium nitrate and 2.28 g L-1 potassium nitrate using a concentration of saccharose 20g L-1. Mean shoot and root lengths under optimal concentrations were 5.82 cm and 3.0 cm, respectively. In contrast, MS basic culture media represented the treatment of least growth induction; yielding un rooted shoots of a mean length of 2.94 cm. Of these three native varieties, "Cucuba" proved to have the highest growth rates. All of the Vitroplantlets were then transferred to liquid MS media, with a saccharose concentration of 8 %, originating microtubers after 90 days. We conclude that these findings may be of use for massive in vitro production of native potato varieties. Palabras clave (en_US)

87-94

Authors: Victor Julio Atencio García, María Dorado Longas, César Montes Prieto, Martha Prieto-Guevara, José Espinosa-Araujo

The aim was assess thawed sperm quality of dorada Brycon moorei, cryopreserved with dimethylsulfoxide (DMSO) to three inclusion rate. The sperm was obtained from nine males, kept in captivity in the Repelón Fish Farming Station (Atlántico, Col), were induced with carp pituitary extract (4.5 mg/kg). The semen was diluted with an extender composed of DMSO to three inclusion rates (5%, 10% and 15%); 6% glucose and 12% egg yolk. The sperm was diluted in 1:3, packed in macrotubes of 2.5 mL and freeze with vapors of nitrogen and after three months were thawed at 35°C for 90 s. The fresh sperm was considered as control treatment. The thawed semen was analyzed total motility, types of motility, progressivity, velocities and sperm concentration with the Sperm Class Analyzer SCA® software; further, volume, color and activation time were measured in fresh semen. The fresh sperm showed motility greater than 80% and activation time between 28.5 and 41 s; whereas that sperm concentration ranged between 10188.1 and 14590.2 million/ml. The total motility of thawed sperm was higher when DMSO was included at 5% (40.1±5.0%) or DMSO 10% (43.3±8.7%) (p> 0.05); but with 15% DMSO, were registered the low motility (30.6±7.9%) and the highest percentage of immotile sperm (69.4±7.9%) (p<0.05); which suggests inclusions of DMSO above 10% cause greater damage to dorada spermatozoa. The results showed that DMSO should be included between 5 and 10%, along with 6% glucose and 12% egg yolk for cryopreservation of dorada sperm.

105-117

Authors: Yamile Adriana Celis Bustos, Vivian Vanesa Rubio, María Marcela Camacho Navarro

Antimicrobial resistance is a natural aspect of bacterial evolution that can result from mutations or acquisition of foreign genes. Various views on the origin of this resistance explain the ability of these organisms to acquire new features. Lamarck andDarwin’s theories of evolution have led to experiments designed to explore the origin of bacterial variation and the emergence of new features. These experiments show that antimicrobial resistance is related to mutations in chromosomal genes and/or transfer of extrachromosomal genetic elements that can be expressed based on the antibiotic pressure exerted. The main experiments and findings that seek to explain the phenomenon of antibiotic resistance are reviewed here in.

133-139

Authors: Eder Durango Ballesteros, Alicia Humanez Álvarez

The Caña Agria (Cheilocostus speciosus, J. Koenig) is a decorative floral plant, used in the production of handicrafts derived from the Cane Flecha (Gynerium sagittatum, Aubl.), in the municipalities of San Andrés de Sotavento and Túchin, department of Córdoba in Colombia, for its properties for the fiber whitening of Caña Flecha. Due to the scarce presence of Caña Agria plants in the indigenous reserves of Túchin and San Andrés de Sotavento, it was considered necessary to investigate new methods of propagation with the objective of forming seed banks that allow to increase the availability of plant material. To do this, stem cuttings of approximately 11 cm in length were selected, and the effect of three concentrations (0.0, 500 and 1000 mg • L-1 of ANA) was evaluated on the rooting. The cuttings were placed in each concentration for 10 days, and after the time, they were transferred to trays with soil under semicontrolled conditions of temperature and humidity. 30 days after the transplant, the percentage of survival and rooting of the cuttings were established. As a result, it was found that ANA treatments increase root formation. The best treatment to root cuttings was the 500 mg • L-1, with a percentage of rooting of 96% at 10 days after induction. On the other hand, the treatments corresponding to 0.0 mg • L-1 and 1000 mg • L-1 generated percentages of rooting of 24% and 70% respectively. The highest number of roots per plant with an average of 8.76 was obtained in the 500 mg • L-1 ANA solution.