Isolation and Identification of a Bacillus sp. from Freshwater Sediment Displaying Potent Activity Against Bacteria and Phytopathogen Fungi.

A bacterium strain isolated from freshwater sediment of San Pablo river of Santiago de Cuba, Cuba was identified as a Bacillus sp. by Matrix-Assisted Laser Desorption/Ionization Time Of Flight Mass Spectrometry. A 16S rRNA gene analysis showed that the isolate A3 belongs to the operational group Bacillus amyloliquefaciens, while the phylogenetic analysis of the gyrA gene sequence grouped it within B. amyloliquefaciens subsp. plantarum cluster, referred now as Bacillus velezensis. In vitro antibacterial studies demonstrated the capacity of the isolate A3 to produce bioactive metabolites against Bacillus subtilis ATCC 11,778, Bacillus cereus ATCC 6633, and Staphylococcus aureus ATCC 25,923 by cross-streak, overlay, and microdilution methods. The strain also showed a high potential against the multidrug-resistant Staphylococcus aureus ATCC 700,699, ATCC 29,213, and ATCC 6538. At pH 8 and 96 h in the medium 2 of A3 culture conditions, the produced metabolites with antibacterial potential were enhanced. Some alterations in the morphology of the phytopathogens Aspergillus niger ATCC 9642, Alternaria alternata CECT 2662, and Fusarium solani CCEBI 3094 were induced by the cell-free supernatant of B. velezensis A3. A preliminary study of the nature of the bioactive compounds produced by the strain A3 showed the presence of both lipids and peptides in the culture. Those results highlight B. velezensis A3 as a promissory bacterium capable to produce bioactive metabolites with antibacterial and antifungal properties against pathogens.

Copper(II) complexes of bis(amino amide) ligands: effect of changes in the amino acid residue.

A family of ligands derived from bis(amino amides) containing aliphatic spacers has been prepared, and their protonation and stability constants for the formation of Cu(2+) complexes have been determined potentiometrically. Important differences are associated to both the length of the aliphatic spacer and the nature of the side chains derived from the amino acid. In general, ligands containing aliphatic side chains display higher basicities as well as stability constants with Cu(2+). In the same way, basicities and stability constants tend to increase when decreasing the steric hindrance caused by the corresponding side-chain. FT-IR, UV-vis and ESI-MS were used for analyzing the complex species detected in the speciation diagram. UV-vis studies showed the presence of different coordination environments for the copper(II) complexes. Complexes with different stoichiometries can be formed in some instances. This was clearly highlighted with the help of ESI-MS experiments.

Geometric isomerism in pentacoordinate Cu2+ complexes: equilibrium, kinetic, and density functional theory studies reveal the existence of equilibrium between square pyramidal and trigonal bipyramidal forms for a tren-derived ligand.

A ligand (L1) (bis(aminoethyl)[2-(4-quinolylmethyl)aminoethyl]amine) containing a 4-quinolylmethyl group attached to one of the terminal amino groups of tris(2-aminoethyl)amine (tren) has been prepared, and its protonation constants and stability constants for the formation of Cu(2+) complexes have been determined. Kinetic studies on the formation of Cu(2+) complexes in slightly acidic solutions and on the acid-promoted complex decomposition strongly suggest that the Cu(2+)-L1 complex exists in solution as a mixture of two species, one of them showing a trigonal bipyramidal (tbp) coordination environment with an absorption maximum at 890 nm in the electronic spectrum, and the other one being square pyramidal (sp) with a maximum at 660 nm. In acidic solution only a species with tbp geometry is formed, whereas in neutral and basic solutions a mixture of species with tbp and sp geometries is formed. The results of density functional theory (DFT) calculations indicate that these results can be rationalized by invoking the existence of an equilibrium of hydrolysis of the Cu-N bond with the amino group supporting the quinoline ring so that CuL1(2+) would be actually a mixture of tbp [CuL1(H(2)O)](2+) and sp [CuL1(H(2)O)(2)](2+). As there are many Cu(2+)-polyamine complexes with electronic spectra that show two overlapping bands at wavelengths close to those observed for the Cu(2+)-L1 complex, the existence of this kind of equilibrium between species with two different geometries can be quite common in the chemistry of these compounds. A correlation found between the position of the absorption maximum and the tau parameter measuring the distortion from the idealized tbp and sp geometries can be used to estimate the actual geometry in solution of this kind of complex.

Hydrogen and copper ion-induced molecular reorganizations in scorpionand-like ligands. A potentiometric, mechanistic, and solid-state study.

Two aza scorpionand-like macrocycles (L2 and L3) have been prepared. L2 consists of a tren amine with two of its arms cyclizized with a 2,6-bis(bromomethyl)pyridine. In L3, the remaining pendant arm has been further functionalized with a fluorophoric naphthalene group. X-ray data on the compounds [H(L3)]ClO4.H2O (1) and [H3(L3)](H2PO4)3.H2O (2) as well as solution studies (pH-metry, UV-vis, and fluorescence data) show the movement of the pendant arm as a result of the protonation degree of the macrocycles and of the formation of intramolecular hydrogen bonds. X-ray data on the complexes [Cu(L2)](ClO4)2]2.H2O (3) and [Cu(L3)](ClO4)2 (4) and solution studies on Cu2+ coordination show the implication of the nitrogen of the arm in the binding to the metal ion. Kinetic studies on the decomposition and formation of the Cu2+ complexes provide additional information about the pH-dependent molecular reorganizations. Moreover, the obtained information suggests that the kinetics of the tail on/off process is essentially independent of the lability of the metal center.

Malformaciones congénitas diagnosticadas por ultrasonido en 6 años (1984-1989) / Congenital malformations ultrasonic diagnosis during 6 years (1984-1989)

Se evalúa el resultado del uso del ultrasonido como método de diagnóstico prenatal de malformaciones congénitas, aplicado en la provincia de Las Tunas en el período comprendido entre el 1 de mayo de 1984 y el 31 de diciembre de 1989. Se realizaron 39 243 estudios y se diagnosticaron 179 fetos malformados. La mayor cantidad de malformaciones correspondió al sistema nervioso central con 104 casos y fue más frecuente la anencefalia con 52 casos. Con malformaciones renales fueron diagnosticados 30 fetos, 11 malformaciones del sistema digestivo y de la pared abdominal anterior, 7 cardiopatías, 7 tumores fetales y 20 casos de otras malformaciones entre las que se encontraron 9 casos de hidrops fetal no inmunológico. Se comprobó el diagnóstico de las malformaciones por Anatomía Patológica y/o Neonatología del Hospital "Dr. Ernesto Guevara de la Serna", en Las Tunas y el Cardiocentro de Ciudad de La Habana

Malformaciones congénitas diagnosticadas por ultrasonido en 6 años (1984-1989) / Congenital alformations ultrasonic diagnosis during 6 years (1984-1989)

Se evalúa el resultado del uso del ultrasonido como método de diagnóstico prenatal de malformaciones congénitas, aplicado en la provincia de Las Tunas en el período comprendido entre el 1 de mayo de 1984 y el 31 de diciembre de 1989. Se realizaron 39 243 estudios y se diagnosticaron 179 fetos malformados. La mayor cantidad de malformaciones correspondió al sistema nervioso central con 104 casos y fue más frecuente la anencefalia con 52 casos. Con malformaciones renales fueron diagnosticados 30 fetos, 11 malformaciones del sistema digestivo y de la pared abdominal anterior, 7 cardiopatías, 7 tumores fetales y 20 casos de otras malformaciones entre las que se encontraron 9 casos de hidrops fetal no inmunológico. Se comprobó el diagnóstico de las malformaciones por Anatomía Patológica y/o Neonatología del Hospital "Dr. Ernesto Guevara de la Serna", en Las Tunas y el Cardiocentro de Ciudad de La Habana

Resultados del pesquisaje de malformaciones fetales por ultrasonido: estudio en 4 años (1984-1987) / Results of screening for fetal malformations by ultrasound: a four-year study (1984-1987)

Se realizó un estudio del resultado del ultrasonido en el diagnóstico de malformaciones fetales. Se estudiaron 20 230 gestantes y se detectaron 95 fetos malformados, lo que representa el 0,46% en el periodo del primero de mayo de 1984 al 31 de diciembre de 1987. La mayor cantidad de diagnósticados se hicieron hasta las 24 semanas con un total de 69 casos. Los defectos del sistema nervioso central ocuparon el primer lugar con un total de 52 casos (54,7%). Dentro de los defectos del sistema nervioso central, la anencefalia fue la malformación más frecuente y la que se diagnosticó más precozmente. La hidrocefalia se diagnosticó tardiamente en 7 casos (58,3%). Se comprobó el diagnóstico de malformaciones en el 100% de los casos diagnosticados mediante anatomía patológica

Resultados del pesquisaje de malformaciones fetales por ultrasonido: estudio en 4 años (1984-1987) / Results of screening for fetal alformations by ultrasound: a four-year study (1984-1987)

Se realizó un estudio del resultado del ultrasonido en el diagnóstico de malformaciones fetales. Se estudiaron 20 230 gestantes y se detectaron 95 fetos malformados, lo que representa el 0,46

en el periodo del primero de mayo de 1984 al 31 de diciembre de 1987. La mayor cantidad de diagnósticados se hicieron hasta las 24 semanas con un total de 69 casos. Los defectos del sistema nervioso central ocuparon el primer lugar con un total de 52 casos (54,7

). Dentro de los defectos del sistema nervioso central, la anencefalia fue la malformación más frecuente y la que se diagnosticó más precozmente. La hidrocefalia se diagnosticó tardiamente en 7 casos (58,3

). Se comprobó el diagnóstico de malformaciones en el 100

de los casos diagnosticados mediante anatomía patológica