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M Soto

Publications and source records attributed to M Soto.

At least 19 recordsLinked to original sources
PubMed2006

Copeptin, derived from isotocin precursor, is a probable prolactin releasing factor in carp.

Control of prolactin (PRL) release is of crucial importance for the multiple functions exerted by PRL in vertebrates. Recently identified hypothalamic PRL-releasing peptides displayed additional neuromodulatory activities and in fish only few could be detected close to lactotrophs. Here we describe the C-terminal peptide processed from the carp isotocin precursor as probable physiologically relevant regulator of PRL release in carp. The amino acid sequence derived from the complete isotocin precursor gene of Cyprinus carpio, predicted a C-terminal peptide uncleaved between the neurophysin (Np) and copeptin (Cp) domain. Accordingly, antibodies against synthetic Np- and Cp-specific oligopeptides both immunodetected a 13kDa protein (cNpCp) in total pituitary proteins and showed abundant immunoreaction in hypothalamic axons in direct contact with lactotrophs in the rostral pars distalis of carp pituitary gland sections. Finally, incubation of cultured carp pituitary explants with purified carp cNpCp resulted in a potent stimulation of PRL release.

Amino Acid Sequence↗
PubMed2006

Immunohistological features of visceral leishmaniasis in BALB/c mice.

It has been reported that the level of protection provided by vaccines against murine visceral leishmaniasis (VL) is low and that progress in research on VL may be due to the lack of appropriate models to study protective immunity. We have analysed the immunohistological features occurring in BALB/c mice after intravenous administration of 10(3), 10(5) and 10(6) parasites of Leishmania infantum. Our results show that in all cases parasite administration leads to the establishment of infection and to the development of quantifiable immunohistological features which are dependent on the inoculum size. This study demonstrates that differences in the parasite challenge result in changes in the evolution of some of the parameters associated with the degree of the infection in the BALB/c model: level of anti-Leishmania antibodies, up-regulation of spleen arginase activity, balance between IFN-gamma and IL-10, extent of lymphoid follicle depletion in the splenic white pulp and ineffective development of hepatic granulomas. Also, and depending on the initial infectious inoculum, the absence of parasites in the bone marrow and the number of mature and empty type granulomas were parameters associated with protection. We think that in this model a challenge of the order of 10(5) parasites should prove useful for vaccine studies against VL.

Animals↗
PubMed2005

Start-up alternatives and performance of an UASB pilot plant treating diluted municipal wastewater at low temperature.

Different start-up procedures of an upflow anaerobic sludge bed (UASB) digester were carried out. Start-up without inoculum (experiment A) was delayed for about 120 day. The digester reached 75-85% total suspended solids (TSS) removal, 54-58% total chemical oxygen demand (TCOD) removal and 63-73% biological oxygen demand (BOD5) removal at influent concentrations of 240-340 mg TCODil-1, temperatures of 13.5-15 degrees C and hydraulic retention times (HRT) of 10-11 h. Digested sludge was used as inoculum in experiment B. After the start-up period of 75 days, digester efficiencies were 58%, 41% and 54% for TSS, TCOD and BOD5 removal, respectively, working at 169 mg TCODil-1, temperature of 14 degrees C and HRT of 11 h. The sludge bed developed and stabilised quickly when using a hydraulically adapted inoculum (experiment C), but TCOD and BOD5 removals remained low and volatile fatty acids (VFA) accumulated in the effluent.

Bacteria, Anaerobic↗
PubMed2005

Effect of LACK and KMP11 on IFN-gamma production by peripheral blood mononuclear cells from cutaneous and mucosal leishmaniasis patients.

The immune modulatory properties of recombinant antigens Kinetoplasmid membrane protein-11 (KMP11) and Leishmania homologue of receptors for activated C kinase (LACK) in cutaneous leishmaniasis (CL) and mucosal leishmaniasis (ML) patients were evaluated. The mean levels of interferon-gamma (IFN-gamma) in soluble leishmania antigen (SLA) stimulated peripheral blood mononuclear cells (PBMC) of ML and CL patients were 5625 +/- 2333 pg/ml and 4422 +/- 3665 pg/ml, respectively. IFN-gamma was not detected in cultures stimulated with KMP11 or LACK. Interleukin-10 (IL-10) concentration in SLA, KMP11 and LACK-stimulated PBMC of ML patients was 13 +/- 12 pg/ml, 285 +/- 388 pg/ml and 802 +/- 483 pg/ml, respectively. Addition of KMP11 or LACK to SLA-stimulated PBMC of CL and ML patients enhanced IL-10 production (P < 0.05). Addition of KMP11 decreased IFN-gamma levels by 52% in CL patients and by 19% in ML patients. Addition of LACK to SLA-stimulated cultures decreased IFN-gamma levels by 58% in CL patients and by 30% in ML patients. Neutralization of IL-10 abrogated the downregulatory effect of LACK and KMP11. The modulatory properties of LACK and KMP11 are due to induction of IL-10 production and may be helpful for attenuating chronic inflammatory diseases. However, in some clinical conditions, as demonstrated for ML, these molecules are not able to suppress the IFN-gamma response, even inducing IL-10 production.

Adolescent↗
PubMed2005

Recombinant leishmania antigens for serodiagnosis of visceral leishmaniasis.

Serological tests with crude or recombinant Leishmania antigens are important tools for the diagnosis of leishmania infection. However, these tests are not markers of active visceral leishmaniasis (VL), since antibodies to these markers are often observed in individuals with subclinical L. chagasi infection and they do not fall shortly after therapy. In this study, levels of immunoglobulin G (IgG) against three recombinant Leishmania antigens (rH2A, KMP11, and the "Q" protein) were evaluated in sera from individuals with subclinical L. chagasi infection and in patients with VL pre- and posttherapy. The sensitivity of the serological test for diagnosis of VL was 100% with all three antigens. The titers of IgG fell significantly after therapy. While most of the individuals with subclinical L. chagasi infection had antibodies to rH2A and the "Q" protein, only 1 out of 15 individuals had antibodies to KMP11. These data indicate that KMP11 may be used to discriminate L. chagasi infection from active VL and may serve as a marker of response to therapy.

Animals↗
PubMed2004

Performance of a UASB-digester system treating domestic wastewater.

The anaerobic treatment of raw domestic wastewater by a novel technology consisting of an Up-flow Anaerobic Sludge Bed (UASB) reactor combined with a completely mixed digester for the stabilisation of the UASB sludge was assessed. A pilot-scale plant of the so-called UASB-Digester system was located at the municipal wastewater treatment facility of Santiago de Compostela (Northwest of Spain). The main aim of the Digester was to enhance the biodegradation of influent solids retained in the UASB reactor at low temperatures, then increasing its specific methanogenic activity. The sludge drawn from the middle zone of the UASB entered the upper zone of the Digester and then circulated from the bottom of the Digester to the UASB bottom. Circulating in an automated semi-continuous way, the flow of this sludge stream was selected in order to set a previously defined hydraulic retention time (HRT) (16-27 d) in the digester. The Digester temperature was set at an optimum value ranging from 25 to 35 degrees C. The steady state efficiency of the UASB system, at 6-8 h of HRT, 15-16 degrees C of temperature and 330-360 mg l(-1) of influent total chemical oxygen demand (TCOD) was 79% of total suspended solids (TSS) removal, 52% of TCOD removal and 60% of biological oxygen demand (BOD5) removal. The hydrolysis of retained solids reached 85%, while excess sludge generation was only 7% of influent TCOD. A stable anaerobic (pre)treatment of diluted domestic wastewater was reached as the sludge concentration in the reactor remained mainly constant and the specific methanogenic activity showed a slight increase.

Bacteria, Anaerobic↗
PubMed2003

A Leishmania infantum multi-component antigenic protein mixed with live BCG confers protection to dogs experimentally infected with L. infantum.

The capacity of a quimeric protein, formed by the genetic fusion of five antigenic determinants from four Leishmania proteins, formulated with BCG, to protect dogs against Leishmania infantum infection is described. The data showed that after i.v. administration of 500,000 parasites of the L. infantum M/CAN/ES/96/BCN150 strain, zymodeme MON-1, the animals became infected as suggested by the humoral response against the parasite antigens. All control unvaccinated dogs had parasites in the lymph nodes at day 150 post-infection. One of these unvaccinated infected dog was parasite negative at day 634 behaving, thus, as resistant. In contrast, only 50% of the immunized dogs had parasites in the lymph nodes at day 150 post-infection. Four of these dogs became parasite negative by day 634 post-infection. The control animals developed at various times during the follow-up period clinical symptoms associated with Leishmaniasis. The control diseased dogs developed also in the liver and spleen some of the abnormal histological features associated with natural visceral Leishmaniasis. The immunized dogs, however, were not only normal at the clinical but also at the anatomo-pathological level. A positive delayed type hypersensitivity (DTH) response was observed in nine of the immunized protected dogs. The data indicated that Q+BCG confers 90% protection against infection and at least 90% protection at the clinical level.

Animals↗
PubMed2003

Leishmania infantum possesses a complex family of histone H2A genes: structural characterization and analysis of expression.

We have studied the genomic organization and transcription of the histone H2A genes in the protozoan parasite Leishmania infantum. In the parasite genome 2 gene clusters exist, each containing 3 H2A gene copies. Sequence analyses showed the existence of significant sequence divergence among the H2A genes, mainly in their 5'- and 3'-untranslated regions (UTRs). Also, the existence of allelic alternatives has been evidenced. Based on the divergence in the 3'UTR regions, we have defined 3 classes of H2A transcripts, which are present at different levels in L. infantum promastigotes. However, transcription of the 3 classes of H2A genes occurs at similar levels, as measured by nuclear run-on assays, indicating that their abundance is regulated post-transcriptionally. Also, differences in regulation were observed among the H2A transcripts: the levels of transcripts with 3'-UTR type I and type III are affected by growth phase whereas transcripts with 3'-UTR type II, that are barely detected, remain constant. It is likely that the complexity, in both gene organization and differential expression exhibited by the L. infantum H2A genes, is imposed by the nature of the post-transcriptional mechanisms of regulation operating in this parasite.

Amino Acid Sequence↗
PubMed2003

Anaerobic hydrolysis of a municipal wastewater in a pilot-scale digester.

Raw domestic wastewater from the city of Santiago de Compostela (Northwest Spain) was fed into a pilot-scale hydrolytic up flow sludge bed (HUSB) digester with an active volume of 25.5 m3. The total influent chemical oxygen demand (COD) ranged from 360 to 470 mg/l, the influent SS varied from 190 to 370 mg/l, and the temperature was between 17 degrees and 20 degrees C. The organic load rate (OLR) applied increased step by step from 1.2 to 3.9 kgCOD/m3 x d, while the hydraulic retention time (HRT) decreased from 7.1 h to 2.9 h. A high suspended solids (SS) removal of about 82-85% from the influent was reached, most of which (81 to 88%) was eliminated by hydrolysis, while the rest remained in the purge stream. The total COD removal ranged from 46 to 59%. On the other hand, a high acidification of the COD remaining in the effluent was obtained, so the percent COD in the form of volatile fatty acids (VFA(COD)) with respect to total effluent COD was about 43% for the highest HRT applied, and about 27% for the lowest HRT. The soluble to total COD ratio (CODs/CODt) increased from 25-32% for the influent to 71-86% for the effluent. The results obtained confirm the viability and interest of direct anaerobic hydrolytic pre-treatment of domestic wastewater.

Bacteria, Anaerobic↗
PubMed2003

Anaerobic hydrolysis of primary sludge: influence of sludge concentration and temperature.

Anaerobic hydrolysis of primary sludge from urban wastewater treatment was first studied as part of anaerobic sludge stabilisation and later as a process for readily biodegradable matter (volatile fatty acids) production in order to improve biological nutrient removal. Furthermore, hydrolysis was found to be the rate limiting step in both single- or two-step anaerobic treatment of domestic wastewater. However, the influence on the process of several factors such as sludge concentration and temperature is still barely understood, as are kinetic aspects. The aim of this work was to study the influence of sludge concentration and temperature on the hydrolytic and acidogenic conversion of primary sludge and to determine the hydrolysis kinetic coefficients at different temperatures. Specific VFA production varied from 0.17 to 0.34 gVFA(COD)/gVSS of raw primary sludge, depending mainly on the assay sludge concentration and, to a lesser extent, on the process temperature. The first-order hydrolysis constants were 0.038, 0.095 and 0.169 d(-1) for 10, 20 and 35 degrees C, respectively.

Adsorption↗
PubMed2001

Calcium-induced conformational changes in Leishmania infantum kinetoplastid membrane protein-11.

Total-reflection X-ray fluorescence has been used to study whether the Leishmania infantum kinetoplastid membrane protein-11 is a Ca2+-binding protein. The 108 amino acid helix-loop-helix protein has the loop region located between residues 45 and 57, having similarity to the EF-hand motifs. In particular, the sequence alignment of the putative motif revealed the existence of 67% similarity and 33% identity with the EF-hand of the plasmodia-specific 40-kDa protein from Physarum polycephalum. To address the type of conformational changes induced by Ca2+ binding, circular dichroism and fluorescence spectroscopy were used. The data showed that Ca2+ induces changes in both the secondary and tertiary structure of the protein in a temperature- and pH-dependent way. It also induces the precipitation of the protein at pH 7.5, in contrast with what occurs at pH 5.0, and the precipitation process can be reverted by addition of EGTA. At acidic pH values the complex EGTA-Ca2+ causes drastic structural changes, forcing the protein to adopt a structure close to that of a random coil. Because, at acidic pH values, protein:Ca2+:EGTA ternary complexes may be formed, the drastic change may be attributed to the presence of a high density of EGTA negative charges in the neighborhood of the alpha-helices.

Amino Acid Sequence↗
PubMed2001

[Schistosomiasis of the spinal cord. Case report].

The authors report a case of a 34 year-old woman who, in the last four years, had travelled to Africa frequently, and developed a progressive clinical (about three months) dysfunction of the conus medullaris mainly consisting in sensitive disturbances. The MRI showed an intramedullary spinal cord lesion, and specific laboratory tests were negative. A biopsy for histologic diagnosis, showed a granulomatous tissue with eggs of S. Hematobium. After this diagnosis she was treated with praziquantel. We emphasize the relative frequency of the spinal cord location of schistosomiasis in endemic countries, and the importance of the laboratory diagnosis to start an early and effective antischistosomal treatment. Spinal cord schistosomiasis is uncommon but we must bear in mind this possibility in patients with a progressive spinal cord afectation.

Adult↗
PubMed2001

Characterization of aspercetin, a platelet aggregating component from the venom of the snake Bothrops asper which induces thrombocytopenia and potentiates metalloproteinase-induced hemorrhage.

Thrombocytopenia occurs in a number of patients bitten by Bothrops asper, a species responsible for the majority of snakebites in Central America and southern Mexico. In this work we describe the isolation of a new platelet-aggregating protein, named aspercetin, from the venom of B. asper, which induces thrombocytopenia in mice. Isolation was carried out by a combination of ion-exchange chromatography on DEAE-Sepharose and affinity chromatography on Affi-Gel Blue. Aspercetin is a disulfide-linked heterodimer, with a pI of 4.5 and a molecular mass of 29,759 Da, detemined by MALDI-ESI mass spectrometry. N-terminal sequence shows homology with a number of venom proteins which belong to the C-type lectin family. Aspercetin has functional similarities with botrocetin, from B. jararaca venom, since it induces platelet aggregation only in the presence of plasma or purified von Willebrand factor. Aspercetin-mediated platelet aggregation results from the interaction of von Willebrand factor with platelet receptor GPIb. Aspercetin lacks anticoagulant effect and does not agglutinate erythrocytes, in contrast with other representatives of the C-type lectin family isolated from snake venoms. Moreover, aspercetin is not lethal, nor does it induce myonecrosis, hemorrhage and edema. When injected intravenously or intramuscularly in mice it induces a rapid, dose-dependent drop in platelet counts and prolongs the bleeding time, suggesting that it may play a role in the thrombocytopenia that develops in a number of B. asper envenomations. Moreover, mice injected intravenously with aspercetin and then receiving an intradermal injection of B. asper hemorrhagic metalloproteinase BaP1 develop a larger hemorrhagic lesion than mice receiving only BaP1. This suggests that aspercetin, by reducing platelet numbers, may

Amino Acid Sequence↗
PubMed2001

Influence of HRT (hydraulic retention time) and SRT (solid retention time) on the hydrolytic pre-treatment of urban wastewater.

This work presents the results obtained from a study on the pretreatment of urban wastewater using a digester that acted as a system for the retention of solids (sedimentation-filtration), hydrolysis of the retained solids and acidification of the dissolved substances. After start-up (Phase I), the digester was operated at hydraulic retention times (HRT) of 4.4, 3.4 and 2.2 h and at solid retention times (SRT) of 24, 16 and 14 d, during Phases II, III and IV, respectively. The retention and removal of suspended solids (SS) was maintained slightly above 60%, independently of HRT and SRT. Conversely, eliminated chemical oxygen demand (COD) decreased slightly upon reducing HRT and SRT. The influence of these two parameters on the generation of volatile fatty acids (VFA) is more notable, reaching effluent VFA concentration of 29 (Phase II), 96 (Phase III), and 107 (Phase IV) mg COD/I. VFA to SS generation ratios were 0.13 (II), 0.35 (III), and 0.48 (IV) g VFACOD/g SS added. Optimum values were reached at an HRT of 2.2 h. Taking 100 kg influent COD as a base, the conversion of different kinds of COD was as follows (in kg influent: kg effluent): VFACOD(4:17), non-VFA soluble COD (45:23), VSSCOD (51:23). Simultaneously to these conversions, 2 kg VSSCOD are generated as purge stream and 35 kg COD are eliminated during the process.

Bacteria, Anaerobic↗
PubMed2000

Immune and clinical parameters associated with Leishmania infantum infection in the golden hamster model.

For experimental infections with viscerotropic strains of Leishmania, a suitable animal model is not yet defined. In the present work, we have reappraised the use of golden hamster (Mesocricetus auratus) as an experimental model for infection with Leishmania infantum. Groups of hamsters were challenged by the intracardial route with doses ranging from 10(3) to 10(5) infectious promastigotes and the animals were monitored for 1-year follow-up period. The outcome of the infection was assessed by clinical symptoms of leishmaniasis, parasite loads in both liver and spleen, humoral response to Leishmania antigens and antibody levels in kidneys. The humoral response was analysed using either crude antigens (by ELISA and Western blotting) or several recombinant Leishmania antigens (Hsp70, Hsp83, LiP2a, LiP2b, H2A, H3 and KMP-11). From the analysis of all these parameters, we established the existence of three groups of animals: symptomatic or susceptible, oligosymptomatic, and resistant. Given the parallelism existing between the outcomes of Leishmania-infection in hamsters, dogs and humans, we believe that our data illustrate that the hamster is an excellent experimental model to study visceral leishmaniasis and for the design of vaccine development.

Animals↗
PubMed2000

Changes in mussel biometry on exposure to metals: implications in estimation of metal bioavailability in 'Mussel-Watch' programmes.

The occurrence of changes in flesh and shell weights and in other biometric parameters of mussels, Mytilus galloprovincialis, has been related to different metal levels found in their soft tissues. The effects of clean and Zn-polluted environments and laboratory experiments where Zn-polluted mussels were exposed to sublethal concentrations of Zn, Cu and Cd were investigated. Zinc-polluted mussel shell weights increased significantly after a 51-day depuration period. Exposure of Zn-polluted mussels to Zn or Cd, however, caused a slightly reduced shell growth in comparison with depurating mussel Cu-exposures not causing any reduction in growth. Apart from metal concentrations, metal/shell weight indices have been used to assess metal bioavailability. Metal concentrations recorded in the soft tissues of depurating mussels increased without a source of 'extra' metals, while the Zn/shell-weight index was reduced, as expected from a depuration process, Cu and Cd/shell-weight indices remaining constant. Experimental exposure to Zn, Cu and Cd caused augmented values of Zn, Cu and Cd/shell-weight indices, respectively. These different findings were attributed to changes in flesh weight (related with gamete spawning) that would produce inconsistent estimates of whole metal concentration in soft tissues. Since changes in the tissue composition and in growth rates do not affect Zn/Cu ratios and metal/shell-weight indices, these parameters are proposed as reliable indices of metal bioavailability for 'Mussel-Watch' monitoring programmes. The most sensitive parameter is the metal/shell-weight index, which is, therefore, highly recommended to be used in 'Mussel-Watch' monitoring programmes in order to determine metal bioavailability in seawaters.

Animals↗