Scielo RSS <![CDATA[Electronic Journal of Biotechnology]]> http://www.scielo.cl/rss.php?pid=0717-345819990003&lang=es vol. 2 num. 3 lang. es <![CDATA[SciELO Logo]]> http://www.scielo.cl/img/en/fbpelogp.gif http://www.scielo.cl <![CDATA[<B>BIOLOGICAL WARFARE, BIOTERRORISM, BIODEFENCE AND THE BIOLOGICAL AND TOXIN WEAPONS CONVENTION</B>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34581999000300001&lng=es&nrm=iso&tlng=es Biological warfare is the intentional use of micro-organisms, and toxins, generally of microbial, plant or animal origin to produce disease and death in humans, livestock and crops. The attraction of bioweapons in war, and for use in terroristic attacks is attributed to easy access to a wide range of disease-producing biological agents, to their low production costs, to their non-detection by routine security systems, and to their easy transportation from one place to another. In addition, novel and accessible technologies give rise to proliferation of such weapons that have implications for regional and global security. In counteraction of such threats, and in securing the culture and defence of peace, the need for leadership and example in devising preventive and protective strategies has been emphasised through international consultation and co-operation. Adherence to the Biological and Toxin Weapons Convention reinforced by confidence-building measures sustained by use of monitoring and verification protocols, is indeed, an important and necessary step in reducing and eliminating the threats of biological warfare and bioterrorism <![CDATA[<B>VNTR-based diversity analysis of 2x and 4x full-sib <I>Musa</I> hybrids</B>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34581999000300002&lng=es&nrm=iso&tlng=es The triploid plantain landrace Obino l’Ewai (Musa spp., AAB genome) has been crossed with a wild diploid banana (M. acuminata subsp. burmannica var. ‘Calcutta 4’, AA genome) to generate full-sib diploid and tetraploid hybrids combining good agronomic performance and disease resistance. Microsatellite marker analysis of the parental genotypes confirmed the highly heterozygous nature of both parental genotypes. Comparative analysis of 2x and 4x full-sib hybrids with their parental genotypes indicated that tetraploid hybrids are generally more closely related to Obino l’Ewai than their diploid full-sibs. Based on VNTR analysis it is possible to identify those hybrids, which may be most useful in subsequent breeding of secondary triploid hybrids. There was a significant (P<0.05) negative association between the VNTR-based genetic similarity of hybrids to Obino l’Ewai and a phenotypic distance index based on eight agronomic descriptors. However, there was no association between the molecular genetic similarity of hybrids to Calcutta 4 and the respective phenotypic distance index. Many microsatellite markers generated an unexpectedly high number of amplification products from AA and AAB genotypes plus their progeny which may suggest the presence of a high frequency of loci duplication in both A and B genomes, in addition to the detection of heterozygous and/or homoeologous loci. <![CDATA[<B>Visualization and Functional Analysis of a Maxi-K Channel (<I>mSlo</I>) Fused to Green Fluorescent Protein (GFP)</B>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34581999000300003&lng=es&nrm=iso&tlng=es We have constructed a fusion protein between mSlo (a recombinant, high conductance, calcium-activated potassium channel or maxi-K), and GFP (green fluorescent protein). This construct represents a tag to not only monitor channel expression, but to locate the protein in living cells. The GFP was fused in frame to the carboxy-terminus of the mSlo core protein (mSlo-GFP fusion protein). Expression of this fusion protein in COS-7 cells resulted in robust fluorescence localized near the cell membrane. Fluorescing cells that were patch clamped exhibited whole cell currents with a direction consistent with potassium currents. Conversely, non-fluorescing cells showed no significant whole cell currents. Excised inside out patches revealed single channel currents and calculated conductances in the range of those expected for the maxi-K. The mSlo and mSlo-GFP channels reconstituted into lipid bilayers bound wild-type, recombinant CTX with high affinity and displayed a half-blocking concentration (K D) of 7.4 and 7.6 nM, respectively (at +30 mV in 150 mM equimolar KCl). This resulted in single channel evaluation of the functional inhibition of CTX on these clones. As newly constructed GFP chimeras emerge for the study of physiological processes in living organisms, this work provides another area of insight illuminated by GFP. <![CDATA[<B>Isolation by PCR-based methods of a plant antifungal polygalacturonase-inhibiting protein gene</B>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34581999000300004&lng=es&nrm=iso&tlng=es A polygalacturonase-inhibiting protein (pgip) gene from Malus domestica cv Granny Smith apple fruit was cloned by degenerate oligo-primed polymerase chain reaction (PCR) and Inverse PCR. An alignment of the pear and bean PGIP sequences was used to design degenerate PCR primers in highly conserved regions. Degenerate PCR allowed the amplification of a 351bp internal fragment of the pgip gene, termed ipgip. The DNA sequence of ipgip was used to design Inverse PCR primers. A Southern blot of apple genomic DNA probed with the ipgip fragment was used to identify restriction enzyme sites for Inverse PCR. Inverse PCR enabled cloning of the remainder of the gene, from which a composite pgip gene sequence was constructed. A new set of PCR primers were designed to the 5' and 3' ends of the gene, which allowed amplification of the full-length gene from apple genomic DNA. This method has broad application to isolation of homologues of any gene for which some sequence information is known.