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E Cervantes

Publications and source records attributed to E Cervantes.

13 recordsLinked to original sources
PubMed2004

Aphrodisiac properties of Montanoa tomentosa aqueous crude extract in male rats.

Cihuapatli, the Mexican zoapatle (Montanoa tomentosa) has an extensive ethnomedical history of use as a traditional remedy for reproductive impairments. During the study of the ejaculatory function in rats and by testing a set of Mexican plants with medicinal properties, we observed that crude extracts of M. tomentosa facilitated ejaculation. Thus, we decided to analyze the possibility that this plant possessed sexual stimulant properties. To that aim, copulatory behavior of sexually active male rats receiving doses of 38, 75 and 150 mg/kg of the aqueous crude extract of M. tomentosa, as it is prepared in traditional medicine, was assessed. In addition, we evaluated the effect of the 75-mg/kg dose of the extract on males with anesthetization of the genital area and on sexual behavior of sexually inactive male rats (noncopulators). Results showed that acute oral administration of crude extracts of M. tomentosa facilitates expression of sexual behavior in sexually active male rats, significantly increases mounting behavior in genitally anesthetized animals and induces the expression of sexual behavior in noncopulating males. Altogether, these data reveal a facilitatory action of this extract on sexual activity and particularly on sexual arousal. Present findings provide experimental evidence that the crude extract preparation of M. tomentosa, used as a traditional remedy, possesses aphrodisiac properties.

Animals↗
PubMed2002

Significant large-scale chromosome territory movement occurs as a result of mitosis, but not during interphase.

PURPOSE: To investigate large-scale relative movement (position change) of interphase chromosome territories (ICT), as indicated by the separation of chromosome derivatives following exposure to ionizing radiation. MATERIALS AND METHODS: A simple experiment was conducted to investigate large-scale movement of ICT, using whole chromosome 18 painting to measure the frequency of fluorescent ICT in irradiated lymphocytes, cultured over 9 days (seven cell cycles). After chromosome 18 painting, derivative chromosome territory separation was indicated by the observation of three fluorescent ICT in aberrant cells compared with the presence of two fluorescent ICT in normal cells. The frequencies of interphase nuclei containing three fluorescent chromosome territories for unirradiated resting lymphocytes and for lymphocytes acutely irradiated with 2.25 or 5.5 Gy 137Cs gamma-rays were measured for each culture time point of 0, 1, 2, 3, 4, 7 and 9 days. RESULTS: No significant difference was observed in the frequency of three ICT between the average of the controls and irradiated cells cultured for 0, 1 and 2 days. However, irradiated cells cultured for >or=3 days showed a significant increase in the frequency of three fluorescent ICT over those cultured for <or=2 days, as well as over all controls. The frequency of cells containing three territories for cultures that received a dose of 5.5 Gy was about twice that for cultures that received a dose of 2.25 Gy for 3-, 4-, 7- and 9-day cultures. CONCLUSION: The finding that significant large-scale movement was not observed within the first 48 h of cell culture, but was seen in cultures after 48 h, suggests that ICT do not undergo large-scale movement relative to each other until lymphocytes go through mitosis.

Chromosome Aberrations↗
PubMed2001

Mesorhizobium chacoense sp. nov., a novel species that nodulates Prosopis alba in the Chaco Arido region (Argentina).

Low-molecular-weight RNA analysis was performed for the identification and classification of 20 Argentinian strains isolated from the root nodules of Prosopis alba. SDS-PAGE of total cellular proteins, determination of the DNA base composition, DNA-DNA reassociation experiments and physiological and biochemical tests were also carried out for these strains and the whole 16S rRNA gene was sequenced from one of the strains, strain LMG 19008T. Results of the genotypic and phenotypic characterization showed that the strains isolated in this study belong to a group that clustered in the genus Mesorhizobium. The results of DNA-DNA hybridizations showed that this group is a novel species of this genus. The name Mesorhizobium chacoense sp. nov. is proposed for this species. The type strain is LMG 19008T (= CECT 5336T).

Anti-Bacterial Agents↗
PubMed2000

Staircase electrophoresis profiles of stable low-molecular-weight RNA--a new technique for yeast fingerprinting.

Staircase electrophoresis (SCE) in polyacrylamide gels was used to analyse the stable low-molecular-weight (LMW) RNA profiles of several yeast species and genera. As in prokaryotes, this new electrophoretic technique results in good separation of molecules forming LMW RNA profiles in yeasts. In this study it is reported that, while LMW RNA profiles in prokaryotes include only 5S rRNA, and class 2 and class 1 tRNA, these profiles in eukaryotes also include 5.8S rRNA. Differences in the number and distribution of RNA bands in these profiles allowed identification of differences among the yeast species and genera assayed. LMW RNAs, analysed by SCE, provide a yeast fingerprint that allows them to be clearly differentiated and will in the future enable the rapid assignment of yeast isolates to already described species and the detection of new ones.

Electrophoresis, Polyacrylamide Gel↗
PubMed1998

Analysis of LMW RNA profiles of Frankia strains by staircase electrophoresis.

An optimized technique of polyacrylamide gel electrophoresis, Staircase Electrophoresis (SCE), was applied to determine the stable Low Molecular Weight RNA (LMW RNA) profiles of 25 Frankia strains from diverse geographic origins and host specificity groups as well as species from other actinomycete genera. Application of the technique permits the rapid identification of Frankia strains and their differentiation from other actinomycetes. The isolates used in this study were grouped in eight clusters, each comprising strains with identical LMW RNA profiles. Comparison of these results with others obtained from DNA sequences or DNA hybridization methods suggest a high degree of complexity in the genus Frankia. Application of SCE to profile LMW RNA should in the future facilitate biodiversity studies of Frankia and discrimination of new species.

Actinomycetales↗
PubMed1994

Ethylene regulates the expression of a cysteine proteinase gene during germination of chickpea (Cicer arietinum L.).

Synthetic oligonucleotides corresponding to conserved regions of cysteine proteinases were used as primers in the RT-PCR amplification of a fragment of cDNA corresponding to a region of a cysteine proteinase gene expressed during germination of chickpea (cac for Cicer arietinum cysteine proteinase). The identity of the PCR-amplified fragment was confirmed by sequencing and the fragment used as a probe to investigate the pattern of cac gene expression during germination and its hormonal regulation. The corresponding transcript is undetected in the seed during embryogenesis and before imbibition, being detected 24 h after imbibition. Ablation of the embryonic axis before imbibition results in a dramatic decrease in the amount of transcript detected. Expression of the cac transcript in excised cotyledons is restored in the presence of aqueous extracts from embryonic axes and also by incubating the excised cotyledons in 1 mM ethephon. Experiments with various known inhibitors of ethylene action indicate that ethylene activates the expression of cac gene in the cotyledons of chickpea during normal germination.

Base Sequence↗
PubMed1990

Sequence and analysis of the rpoN sigma factor gene of rhizobium sp. strain NGR234, a primary coregulator of symbiosis.

We report the nucleotide sequence of the rpoN gene from broad-host-range Rhizobium sp. strain NGR234 and analyze the encoded RPON protein, a sigma factor. Comparative analysis of the deduced amino acid sequence of RPON from NGR234 with sequences from other gram-negative bacteria identified a perfectly conserved RPON box unique to RPON sigma factors. Symbiotic regulatory phenotypes were defined for a site-directed internal deletion within the coding sequence of the rpoN gene of Rhizobium strain NGR234: they included quantitative nodulation kinetics on Vigna unguiculata and microscopic analysis of the Fix- determinate nodules of V. unguiculata and Macroptilium atropurpureum. RPON was a primary coregulator of nodulation and was implicated in establishment or maintenance of the plant-synthesized peribacteroid membrane. Phenotypes of rpoN in Rhizobium strain NGR234 could be grouped as symbiosis related, rather than simply pleiotropically physiological as in free-living bacteria such as Klebsiella pneumoniae and Pseudomonas putida.

Amino Acid Sequence↗
PubMed1989

The Rhizobium meliloti host range nodQ gene encodes a protein which shares homology with translation elongation and initiation factors.

The Rhizobium meliloti nod region IIb is involved in host-range determination: (i) the presence of region IIb is necessary for transfer of alfalfa root hair curling ability to Rhizobium leguminosarum biovar trifolii; (ii) a mutation in region IIb extends the R. meliloti infection host range to Vicia sativa nigra; (iii) dominance of R. meliloti nod genes over R. leguminosarum biovar viciae nod genes is abolished by mutations in region IIb. The nucleotide sequence of this region has been determined. Genes corresponding to the two open reading frames identified are designated nodP and nodQ. The predicted amino acid sequence of the NodQ protein shows homology with translation initiation and elongation factors. The consensus sequence involved in the GTP-binding domain is conserved.

Amino Acid Sequence↗
PubMedDate not supplied

nodSU, two new nod genes of the broad host range Rhizobium strain NGR234 encode host-specific nodulation of the tropical tree Leucaena leucocephala.

Rhizobium species strain NGR234 nodulates at least 35 diverse genera of legumes as well as the nonlegume Parasponia andersonii. Most nodulation genes are located on the 500-kilobase pair symbiotic plasmid, pNGR234a. Previously, three plasmid-borne host range determinants (HsnI, HsnII, and HsnIII) were identified by their ability to extend the nodulation capacity of heterologous rhizobia to include Vigna unguiculata. In this study, we show that HsnII contains two new nod-box linked hsn genes, nodS and nodU.nodS controls nodulation of the tropical tree Leucaena leucocephala, while the nodSU genes regulate nodulation of the pasture legume Desmodium intortum and the grain legume V. unguiculata. Regulation of the nod-box upstream of nodSU by the flavonoid naringenin was shown using a fusion with a promoterless lacZ gene. Determination of the nucleotide sequence of the nodS gene did not reveal homology with any gene in the EMBL library, although Bradyrhizobium japonicum USDA110 contains both nodS and nodU (M. Göttfert, S. Hitz, and H. Hennecke, Molecular Plant-Microbe Interactions 3:308-316, 1990). We suggest that broad host range in NGR234 is controlled in part by a nodD gene which interacts with a wide range of flavonoids, and in part by host-specific nod genes such as nodS.

Amino Acid Sequence↗