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L Bolaños

Publications and source records attributed to L Bolaños.

9 recordsLinked to original sources
PubMed2001

Lectin-like glycoprotein PsNLEC-1 is not correctly glycosylated and targeted in boron-deficient pea nodules.

Symbiosome development was studied in pea root nodules from plants growing in the absence of boron (B). Rhizobia released into the host cells of nodules from B-deficient plants developed to abnormal endophytic forms with an altered electrophoretic lipopolysaccharide pattern. Immunostaining after sodium dodecyl sulfate-polyacrylamide gel electrophoresis and electroblotting of nodule homogenates with antibodies that recognize glycoprotein components showed that two previously described lectin-like glycoproteins (PsNLEC-1A and PsNLEC-1B) did not harbor the carbohydrate epitope normally recognized by specific monoclonal antibodies. Material derived from B-deficient nodules, however, still contained three antigenic isoforms with similar electrophoretic mobilities to PsNLEC-1 isoforms A, B, and C. These could be detected following immunoblotting and immunostaining with a specific antiserum originating from the purified PsNLEC protein that had been heterologously expressed in Escherichia coli. Immunogold localization of PsNLEC-1 sugar epitopes in B-deficient nodules showed that they were associated mostly with cytoplasmic vesicles rather than normal localization in the symbiosome compartment of mature infected cells. These results suggest that a modification of the glycosyl-moieties of PsNLEC-1 and an alteration of vesicle targeting occur during the development of pea nodules in the absence of B, and that these changes are associated with the development of aberrant nonfunctional symbiosomes.

Animals↗
PubMed1999

Intracerebroventricular infusion of hypertonic NaCl increases urinary CGMP in healthy and cirrhotic rats.

Implication of serum atrial natriuretic peptide (ANP) and endothelin-1 (ET1) in the central nervous system (CNS)-induced natriuresis and hypertension respectively, was investigated in healthy and cirrhotic rats. Both healthy and nonascitic CCl(4)-induced cirrhotic rats under pentobarbital anesthesia received either normotonic (140 mmol/L) or hypertonic (320 mmol/L) NaCl artificial cerebrospinal fluid into the CNS lateral ventricle at a rate of 8.3 microl/min for 120 min. A sham operated group, but not centrally infused, served as matched control. Hypertonic NaCl solution significantly increased mean arterial pressure (MAP) similarly in both healthy (n = 5) ((MAP: 16 mm Hg, 13%) and cirrhotic rats (n = 6) ((MAP: 20 mm Hg, 15%) (ANOVA, p <.001) although the latter showed a slower increment. Under hypertonic NaCl infusion, natriuresis was also significantly increased in a similar manner in both healthy (U (Na) V: baseline: 0.38 +/- 0.22 micromol/min x 100 g; experiment: 2.36 +/- 0.90 micromol/min x 100 g; mean +/- SD) and cirrhotic rats (0.69 +/- 0.48 vs. 3.16 +/- 0.87; p <.001). By contrast, central hypertonic NaCl solutions did not show a significant modification of serum ANP in neither healthy (62 +/- 18 fmol/ml vs. 51 +/- 17 fmol/ml) nor cirrhotic rats (126 +/- 61 vs. 115 +/- 30). Likewise, ET-1 was not significantly modified under central hypertonic NaCl infusion in neither healthy (352 +/- 46 pg/ml vs. 344 +/- 39 pg/ml) nor cirrhotic rats (287 +/- 58 vs. 277 +/- 61). Despite no modification in serum ANP, there was a significant increment in urinary excretion of cGMP under central hypertonic NaCl infusions in bo th healthy (6.8 +/- 4.1 pmol/min x 100 g vs. 13.0 +/- 6.5 pmol/min x 100 g; p <.05) and cirrhotic rats (8.6 +/- 1.7 vs. 11.1 +/- 1.3; p <.05). Our data indicate the preservation of the mechanisms of central natriuresis in a model of non-ascitic CCl(4 )-induced cirrhosis in rats. An increment in urinary cGMP could potentially be implicated in the natriuretic response obtained by intracerebroventricular hypertonic NaCl stimulus in both healthy and cirrhotic rats. The lack of modification of serum ANP and ET-1 does not appear to support a systemic implication of these peptides in the natriuretic and hypertensive responses respectively induced by this manoeuvre.

Animals↗
PubMed1994

Bacterial and plant glycoconjugates at the Rhizobium-legume interface.

Many classes of bacterial and plant glycoconjugate have been shown to be involved in establishing the Rhizobium root nodule symbiosis with peas (Pisum sativum). It was demonstrated, using techniques of molecular genetics, that a group of Rhizobium nodulation genes (nod genes) co-operate to synthesize a lipo-oligosaccharide signal molecule that specifically initiates nodule development on legume hosts. An additional gene function, encoded by nodX, has been found to extend the host range of Rhizobium leguminosarum bv. viciae to include nodulation of a pea mutant, cultivar Afghanistan; the nodX gene product specifies the addition of an acetyl group to the terminal N-acetylglucosamine residue at the reducing end of the pentasaccharide core of this signal molecule. Several other classes of bacterial glycoconjugate have also been shown by genetic analysis to be essential for normal nodule development and function: these include a capsular extracellular polysaccharide; lipopolysaccharide in the outer membrane; and cyclic glucans present in the periplasmic space. Potential functions for these glycoconjugates are discussed in the context of tissue and cell invasion by Rhizobium. Some plant components involved in symbiotic interactions have been identified by the analysis of nodule-specific gene expression (early nodulins). Several of the cDNA clones encoding these early nodulins specify proline-rich proteins that presumably correspond to cell wall glycoproteins or membrane arabinogalactan proteins. Other plant glycoconjugates have been identified using monoclonal antibodies as probes. A plant glycoprotein present in intercellular spaces has been identified as a component of the luminal matrix of infection threads. Because it attaches to the surface of bacteria and is itself susceptible to oxidative cross-linking, this glycoprotein may be involved in limiting the progress of microbial infections. Endocytosis of bacteria into the plant cytoplasm is apparently driven by direct interactions between the bacterial surface and the plasma membrane that is exposed within an unwalled infection droplet; glycoprotein and glycolipid components of the plant membrane glycocalyx have been defined using monoclonal antibodies. Differentiation of endosymbiotic bacteroids is preceded by differentiation of the plant-derived peribacteroid membrane which encloses the symbiosome compartment. Using a monoclonal antibody that identifies a group of plant membrane-associated, inositol-containing glycolipids, we have identified a very early marker for the differentiation of peribacteroid membrane from plasma membrane.

Carbohydrate Sequence↗
PubMed1991

Epidemiologic identification of infants with low birth weight in urban areas of Latin America: II. A simplified risk score for early prenatal identification in Guatemala City.

A simple, empirically derived instrument is needed in developing countries to identify mothers at risk of delivering low birth weight (LBW) infants, in order to help reduce the incidence of LBW deliveries and provide mothers at high risk with appropriate health care. The study reported here was devoted to developing an instrument of this kind using data obtained before the twenty-sixth week of gestation from an urban study population of 17,135 Guatemalan women. It appears that this instrument could be appropriately applied to urban populations in other developing countries.

Adolescent↗
PubMed1988

Perinatal data reliability in a large teaching obstetric unit.

In this inter-rater agreement study of antenatal and neonatal variables collected in a large teaching obstetric unit, information routinely collected by hospital staff was compared with that collected by a specially trained physician and a social worker. Agreement between the two sources of data was evaluated using kappa statistics and intraclass correlation coefficients. Excellent agreement was observed for some variables such as maternal and newborn anthropometric measures, and previous birthweight, but there was poor agreement for others such as indicators of physical activity, work during pregnancy and blood pressure measures. Some of the limitations are due to problems in phrasing questions, patients' recall, interviewer bias and abstracting data. We recommend that epidemiological studies should always include a reliability component, proper standardization of personnel and instruments and include, when published, validity data and examples of questions used.

Adult↗
PubMedDate not supplied

[Atheroembolic disease. Presentation of a case of multisystemic involvement and review of the literature].

The atheroembolic disease is an entity characterized by obstruction of multiple small arteries by cholesterol crystals. The incidence rises steeply with advancing age and following an invasive procedure involving arteries in patients with atherosclerosis. Actually it has a growing interest due to the increased frequency and to the lack of appropriate therapy. In this paper we report a clinical case of multiple system disease secondary to anticoagulant therapy in a 69 years old patient. We review the pathogenesis, clinical features, laboratory dates and pathology of the disease.

Aged↗