Search PubMed⌕ Search

Biomedical subjects

V Bottazzi

Publications and source records attributed to V Bottazzi.

30 records · Page 2Linked to original sources
PubMed1982

Drug resistance plasmids in Lactobacillus acidophilus and Lactobacillus reuteri.

Sixteen strains of Lactobacillus reuteri and 20 strains of Lactobacillus acidophilus were tested for resistance to 22 antibiotics by using commercially available sensitivity disks. Evidence suggesting linkage of these resistances to plasmids was obtained by "curing" experiments with acridine dyes and high growth temperatures. Examination of plasmid patterns of agarose gel electrophoresis provided further evidence of loss in plasmid DNA under curing conditions in some of the strains examined.

Anti-Bacterial Agents↗
PubMed1980

Genetic heterogeneity among Lactobacillus acidophilus strains.

Physiological characteristics, DNA base composition (% GC) and DNA-DNA reassociation values were determined for 138 Lactobacillus acidophilus strains. Twenty seven strains were received from various culture collections and 111 strains were freshly isolated during a study on the composition of the intestinal lactic microflora of piglets and suckling calves. All strains had physiological characteristics which were substantially similar. The strains isolated from pigs were unable to ferment trehalose. The % GC ranged from 35.8 to 43.4. On the basis of the results of DNA-DNA hybridization the strains were divided into four genetic groups.

Animals↗
PubMedDate not supplied

Single-stranded DNA plasmid, vector construction and cloning of Bacillus stearothermophilus alpha-amylase in Lactobacillus.

Vector plasmids were constructed by ligating chloramphenicol and erythromycin resistance genes to TaqI-digested DNA of a cryptic plasmid from Lactobacillus plantarum. The minimal region of Lactobacillus plasmid DNA that was required for DNA replication was defined and a single-stranded DNA intermediate replication system was observed. Homologies with other origins of replication of plasmids from Gram-positive bacteria, replicating via rolling circle mechanism, were found. It was shown that the constructed vectors, named pPSC20 and pPSC22, were transformable into L. plantarum, Lactobacillus acidophilus, Lactobacillus reuteri, Lactobacillus fermentum, Lactobacillus helveticus, Lactococcus lactis subsp. lactis, Bacillus subtilis, and Escherichia coli. Using plasmid pPSC22, the alpha-amylase gene of Bacillus stearothermophilus was cloned and expressed in several Lactobacillus species.

DNA, Single-Stranded↗
PubMedDate not supplied

The interaction between poultry and Triatoma infestans Klug, 1834 (Hemiptera: Reduviidae) in an experimental model.

This paper compares the predation pressure that ducks and chickens exert on triatomines. For the tests, these birds were placed in individual boxes together with a known number of Triatoma infestans and left to interact from 6 p.m. till the next morning, involving a long lasting period of complete darkness limited by two short-term periods of semi-darkness. There was a shelter which could prevent the bugs from being predated. The number of live and dead triatomines was recorded, considering missing bugs as predated by the birds. Ducks exhibited a greater predatory activity than chickens, that could be due to a long term active period at night while chickens sleep motionless from sunset to dawn. Surviving triatomines that had fed on chickens outnumbered those fed on ducks suggesting that these were less accessible to the triatomine biting. If ducks are better than chickens to detect and eat bugs and to interfere with their feeding in the field, an increase in duck number might help to diminish triatomine density. Further research is needed to determine the feasibility of application of these experimental results.

Animals↗
PubMedDate not supplied

Interaction between Didelphis albiventris and Triatoma infestans in relation to Trypanosoma cruzi transmission.

This paper attempts to prove if a high Trypanosoma cruzi prevalence of opossums might be reached with few potential infective contacts. One non-infected Didelphis albiventris to T. cruzi and 10 infected nymphs of Triatoma infestans were left together during 23 hr in a device that simulated a natural opossum burrow. Twenty-six replicates were performed using marsupials and triatomines only once. Potentially infective contacts occurred in all the trials. From the 26 opossums used in trials, 54% did not eat any bug. Of the 260 bugs used, 21% were predated. In the 25 trials involving 205 surviving bugs, 36% of them did not feed. In 15/25 cases, > or = 60% of the triatomines were able to feed. The parasitological follow-up of 24 opossums showed that among 10 that had eaten bugs, 4 turned out infected and among the 14 that had not predate, 3 (21%) became positive. In sum, 7/24 (29%) of the marsupials acquired the infection after the experiment. This infection rate was similar to the prevalences found for the opossum population of Santiago del Estero, Argentina, suggesting that the prevalences observed in the field might be reached if each marsupial would encounter infected bugs just once in its lifetime.

Animals↗
PubMedDate not supplied

Comparative meiotic studies in Triatoma sordida (Stål) and T. guasayana Wygodzinsky & Abalos (Reduviidae, Heteroptera).

Triatoma sordida and T. guasayana are competent Trypanosoma cruzi vectors, with overlapping distribution areas in Argentina. Both species are morphologically similar, and their immature stages are hard to discriminate. Cytogenetic studies in the genus Triatoma reveal scarce karyotypic variations, being 2n = 20 + XY the most frequent diploid number in males. In the present work the meiotic behaviour of different Argentinian populations of T. sordida and T. guasayana has been analyzed; the meiotic karyotype of both species has also been compared. The species differ in total chromosome area and in the relative area of the sex chromosomes. These meiotic karyotypic differences constitute an additional tool for the taxonomic characterization of T. sordida and T. guasayana. The analysis of an interpopulation hybrid of T. sordida (Brazil x Argentina) reveals a regular meiotic behaviour; despite the presence of heteromorphic bivalents. Our observations support the hypothesis that karyotype variations through the gain or loss of heterochromatin can not be considered as a primary mechanism of reproductive isolation in Triatoma.

Animals↗