The major Alternaria alternata allergen, Alt a 1: A reliable and specific marker of fungal contamination in citrus fruits.

The ubiquitously present spores of Alternaria alternata can spoil a wide variety of foodstuffs, including a variety of fruits belonging to the Citrus genus. The major allergenic protein of A. alternata, Alt a 1, is a species-specific molecular marker that has been strongly associated with allergenicity and phytopathogenicity of this fungal species. This study aimed to evaluate the potential of the detection of Alt a 1 as a reliable indicator of A. alternata contamination in citrus fruits. To accomplish this aim, sixty oranges were artificially infected with a spore suspension of A. alternata. Internal fruit material was collected at different incubation times (one, two and three weeks after the fungal inoculation) and used for both total RNA extraction and protein extraction. Alt a 1 detection was then performed by polymerase chain reaction (PCR) amplification using Alt a 1 specific primers and by enzyme-linked immunosorbent assay (ELISA). The experimental model presented in this work was effective to simulate the typical Alternaria black rot phenotype and its progression. Although both PCR and ELISA techniques have been successfully carried out for detecting Alt a 1 allergen in A. alternata infected oranges, the PCR method was found to be more sensitive than ELISA. Nevertheless, ELISA results were highly valuable to demonstrate that considerable amounts of Alt a 1 are produced during A. alternata fruit infection process, corroborating the recently proposed hypothesis that this protein plays a role in the pathogenicity and virulence of Alternaria species. Such evidence suggests that the detection of Alt a 1 by PCR-based assay may be used as a specific indicator of the presence of pathogenic and allergenic fungal species, A. alternata, in fruits. This knowledge can be employed to control the fungal infection and mitigate agricultural losses as well as human exposure to A. alternata allergens and toxins.

Alt a 15 is a new cross-reactive minor allergen of Alternaria alternata.

Alternaria alternata is one of the most common saprophytes worldwide that is clinically and epidemiologically associated with severe asthma. Therefore, the identification and characterization of all A. alternata allergens are of major clinical importance. This study describes a new cross-reactive A. alternata allergen that was officially named Alt a 15 by the official Allergen Nomenclature Subcommittee. The complete coding region for Alt a 15 was amplified using 5' and 3' rapid amplification of cDNA ends and PCR. The recombinant protein was produced in Escherichia coli as a 65-kDa fusion protein, and the protein sequence exhibits high homology with several important fungal allergens. Immunoblotting analyses revealed that IgE antibodies from A. alternata-sensitized patients (n=59) bound to rAlt a 15 with a prevalence of 10.2%. All patients who presented sIgE to rAlt a 15 were apparently poly-sensitized to A. alternata and C. lunata. The extensive cross-reactivity between A. alternata and C. lunata serine proteases was confirmed using immunoblotting inhibition assays. Overall, Alt a 15 is an important new cross-reactive allergen of A. alternata that explains some allergies to A. alternata without Alt a 1 sensitization and initial diagnostic errors for allergies to Alternaria. This molecule may improve the accuracy of the diagnosis, the understanding, and the management of IgE-mediated fungal diseases.

Development of a PCR-based tool for detecting immunologically relevant Alt a 1 and Alt a 1 homologue coding sequences.

Alt a 1 has been recognized as the most important allergen produced by the Pleosporaceae family and is a risk factor for asthma development and/or exacerbation. The aim of this study was to develop a detection tool that is highly specific for species that produced airborne Alt a 1. Based on the highly conserved internal nucleotide region of the several Alt a 1 sequences that are available in GenBank, a pair of primers (Alta1CF/Alta1CR) was designed. A set of primers used by other authors for the production of recombinant Alt a 1 (A21F/A21R) was also tested. The molecular analyses were based on the polymerase chain reaction (PCR) amplification and sequencing of the cDNA that was obtained from thirteen common fungal species. The PCR system that utilized Alta1CF/Alta1CR was highly specific, sensitive, and was able to detect an amplicon of approximately 180 bp from Alt a 1 and Alt a 1-like encoding genes from A. alternata, A. tenuissima, A. infectoria, U. botrytis, and S. botryosum. In contrast, the A21F/A21R primers were specific for the very close taxonomically related species A. alternata and A. tenuissima. Thus, this rapid, sensitive, and specific detection tool can be used to assess Alt a 1 exposure levels and to inform the implementation of the appropriate public health measures.

Diagnostic value of Alt a 1, fungal enolase and manganese-dependent superoxide dismutase in the component-resolved diagnosis of allergy to Pleosporaceae.

BACKGROUND: Over the last decades, genomics and proteomics have contributed to the current knowledge of individualized allergenic components and their potential use in the diagnosis of IgE-mediated allergies. Recent investigations have demonstrated that Alt a 1 should be considered as a relevant allergen of the Pleosporaceae group and that enolase is the main allergen involved in the cross-reactivity to fungi. However, the real utility of these allergens as tools for the diagnosis of allergy to Alternaria is still unclear. OBJECTIVE: To demonstrate the current value of the available fungal allergen panel and the need to build an accurate mould allergen array for the diagnosis of allergy to Pleosporaceae. METHODS: Specific IgEs to individual mould allergens and allergenic mould extracts were evaluated using the ImmunoCAP™ system in 30 patients allergic to Alternaria and in 100 blood donors. Cross-reactivity studies were performed by Fluoro Enzyme ImmunoAssay (FEIA) and FEIA inhibition using individual allergens and allergenic extracts. Two-dimensional electrophoresis associated with a MALDI-TOF analysis was carried out to identify new allergen molecules. RESULTS: All allergic patients had positive specific IgE responses to several moulds from different taxonomical families. Classic and molecular diagnosis demonstrated that 23% of patients had multi-sensitization. The current commercially available fungal allergen array was not sufficient to establish an accurate diagnosis. Unexpected correlations between Alternaria or Alt a 1 and Curvularia or Cladosporium stimulated the investigation of a more accurate allergen panel. A manganese-dependent superoxide dismutase (MnSOD) homologous to Asp f 6 was identified as a new IgE-binding molecule from Alternaria alternata. CONCLUSIONS AND CLINICAL RELEVANCE: Alt a 1 is the marker for allergy to Pleosporaceae, not including Curvularia. MnSOD can explain 6.6% of allergy to Alternaria without Alt a 1 sensitization and should be included together with Alt a 1 and fungal enolase in the molecular array for the diagnosis of allergy to Pleosporaceae.

Development of a qPCR assay for the quantification of porcine adenoviruses as an MST tool for swine fecal contamination in the environment.

The Adenoviridae family comprises a wide diversity of viruses that may be excreted for long periods in feces or urine. Previous studies have suggested that the detection of human and animal adenoviruses as well as human and animal polyomaviruses by PCR could be used as an index of fecal contamination of human and animal origin. In this study, quantitative PCR assays targeting specifically porcine adenoviruses have been developed and applied to fecal and environmental samples, including pig slurries, urban sewage, slaughterhouse sewage and river water samples. To develop real-time quantitative PCR for the detection and quantitation of porcine adenoviruses, primers and a TaqMan probe targeting a 68-bp region of the porcine adenovirus hexon gene were designed to amplify specifically porcine adenovirus, and the conditions of the reaction were optimized. The assay detected 1-10 genome copies per test tube and was specific in showing no positive results when samples containing human or bovine adenoviruses were analyzed. Fecal samples contained mean concentrations of porcine adenoviruses of 10(5) GC/g while slaughterhouse wastewater samples showed mean values of 10(3) GC/ml. The assay detected porcine fecal pollution in samples that were highly diluted and had been collected at a considerable distance from the input source, such as river water. In general, the data presented here provide a quantitative tool for the analysis of porcine adenoviruses as indicators of the presence of porcine contamination in the environment, and support the detection of porcine adenoviruses by real-time quantitative PCR as a promising and valuable tool for source-tracking studies.

Perioperative and short-term advantages of mini-open approach for lumbar spinal fusion.

It has been widely reported a vascular and neurologic damage of the lumbar muscles produced in the classic posterior approach for lumbar spinal fusions. The purpose of this study is to demonstrate a better clinical and functional outcome in the postoperative and short term in patients undergoing minimal invasive surgery ("mini-open") for this lumbar spinal arthrodesis. We designed a prospective study with a 30 individuals cohort randomized in two groups, depending on the approach performed to get a instrumented lumbar circumferential arthrodesis: "classic posterior" (CL group) or "mini-open" approach (MO group). Several clinical and functional parameters were assessed, including blood loss, postoperative pain, analgesic requirements and daily life activities during hospital stay and at the 3-month follow-up. Patients of the "mini-open approach" group had a significant lower blood loss and hospital stay during admission. They also had significant lower analgesic requirements and faster recovery of daily life activities (specially moderate efforts) when compared to the patients of the "classic posterior approach" group. No significant differences were found between two groups in surgery timing, X-rays exposure or sciatic postoperative pain. This study, inline with previous investigations, reinforces the concept of minimizing the muscular lumbar damage with a mini-open approach for a faster and better recovery of patients' disability in the short term. Further investigations are necessary to confirm these findings in the long term, and to verify the achievement of a stable lumbar spinal fusion.

Detection of enterovirus and hepatitis A virus RNA in mussels (Mytilus spp.) by reverse transcriptase-polymerase chain reaction.

AIMS: A simple and effective method of concentrating and purifying enteric viruses from mussel samples to be detected by nucleic acid extraction reverse transcriptase-polymerase chain reaction (RT-PCR) has been evaluated. METHODS AND RESULTS: Seeded mussels were processed by alkaline elution, polyethylene glycol (PEG) precipitation, solvent extraction and PEG precipitation. Final concentrates were assayed by infectivity and RT-PCR after nucleic acid extraction. Two RNA extraction methods were comparatively evaluated for removing inhibitory substances: guanidinium thiocyanate extraction and Purescripttrade mark RNA isolation. Both procedures removed most inhibitors allowing the detection of viral RNA at inoculum levels as low as 4 pfu g(-1) for poliovirus type 1 and 1.8-18 most probable number of cytopathogenic units g(-1) for HAV. When inhibitors remained, they were efficiently removed by Sephadex column chromatography before RNA extraction. CONCLUSION: The described method is effective for the detection of enteric viruses in mussels by RT-PCR. The use of Purescripttrade mark RNA isolation makes the method faster, safer and very easy to perform.

Recovery and detection of enterovirus, hepatitis A virus and Norwalk virus in hardshell clams (Mercenaria mercenaria) by RT-PCR methods.

A method for recovery of enteric viruses from hardshell clams (Mercenaria mercenaria) has been developed and evaluated. Seeded 50-g samples of clam tissue homogenates were processed by adsorption elution precipitation, two fluorocarbon extractions and PEG precipitation. Clam concentrates were assayed by infectivity and by RT-PCR after guanidinium isothiocyanate (GIT) extraction and/or an indirect immunomagnetic capture (IC) of the virus using paramagnetic beads. GIT extraction removed PCR inhibitors and allowed a reliable RT-PCR detection of viral RNA. The detection sensitivity of GIT extraction-RT-PCR was < 1 PFU of poliovirus 1, < 10 PFU of HAV and 1-11 PCRU of Norwalk virus. IC was very effective for additional concentration and purification of enteric viruses from clam concentrates removing most RT-PCR inhibitors. The sensitivity of this method was comparable to the GIT extraction and the sample volume tolerance for PCR was increased about 10-fold. Both methods gave similar efficiency for virus detection in samples seeded with low virus levels. The procedure developed in this study is effective for enteric viruses detection in hardshell clams by RT-PCR.

Minimum inhibitory concentration of smoke wood extracts against spoilage and pathogenic micro-organisms associated with foods.

Antimicrobial activity of seven commercial smoke preparations (four liquid and three solid) was studied. The minimum inhibitory concentration (MIC) was determined against a selection of food spoilage and pathogenic micro-organisms. The main smoke components were identified and quantified by gas chromatography/mass spectrometry. The most effective condensate was S2. All strains except Salmonella enteritidis were inhibited by S2 with an MIC < 0.5-1.5%. Smoke extract L2 inhibited growth of Vibrio vulnificus, Yersinia enterocolitica, Bacillus subtilis, Staphylococcus aureus, Listeria monocytogenes, L. inocua, Brochothrix thermosphacta and Lactococcus lactis ssp lactis with an MIC of < 0.2-0.8%. The condensate L3 inhibited effectively V. vulnificus, B. subtilis, L. innocua and Staph. aureus. L1, L4, S1 and S3 had no inhibitory effects at levels tested against most micro-organisms. Vibrio vulnificus was the most susceptible micro-organism to test compounds. The antimicrobial activity of smoke preparations was related to the concentration of phenols.

Disinfectant tolerance and antibiotic resistance in psychrotrophic gram-negative bacteria isolated from vegetables.

A total of 330 strains of psychrotrophic non-fermenting Gram-negative bacteria isolated from vegetables were studied. In spite of the wide range of antibiotic resistance occurring, less than 10% showed resistance patterns which included mezclocillin-ticarcillin-gentamicin or ceftizoxime-norfloxacin. Reductions of > 5 log10 in the numbers of cfu were found when these strains were exposed for 30 min to a quaternary ammonium compound (1% w/v).

[Serological parameters for the diagnosis and follow-up of toxoplasmosis. Experimental models]. / Parámetros séricos para el diagnóstico y seguimiento de la toxoplasmosis. Modelos experimentales.

BACKGROUND: Toxoplasmosis is a disease of increasing incidence. Its laboratory diagnosis is difficult, specially in acute toxoplasmosis. The data obtained in experimental models attempting to distinguish between acute and chronic toxoplasmosis by the simultaneous study of four serological tests: IgM and IgG antibodies, circulating antigens (CA) and antigens present in immune complexes (IC) are reported. METHODS: The evolution of IgM and IgG antibodies, CA and IC was followed in 3 murine models in acute, subacute and chronic toxoplasmosis, compared with the use of the ELISA technique. RESULTS: Acute toxoplasmosis is characterized by the presence of CA and IC in 100% of the individuals at high concentrations with IgM and IgG only being detectable at low concentrations. In subacute and chronic toxoplasmosis the response to IgG antibodies (100% in animals) is prominent, with detection of IgM being variable and the detection of CA and IC being reduced to the phase considered as acute. CONCLUSIONS: The detection of IgM and IgG antibodies, circulating antigens and immune complexes may be of great usefulness in the differentiation of acute, recently acquired or chronic toxoplasmosis.

[Detection of HBV-DNA in peripheral blood mononuclear cells of anti-HIV-positive patients and its relation to other serological markers of HBV]. / Detección del ADN-VHB en células mononucleares de sangre periférica de pacientes anti-VIH-positivos, y su relación con otros marcadores serológicos del VHB.

HBV infection has been investigated in 47 anti-human HIV positive patients in relation to a similar group of 33 anti-HIV negative patients. Serological HBV markers were found in 87% of anti-HIV positive patients. The difference in markers of viral replication (HBeAg, HBV-DNA) was not statistically significant between the two groups. It has been suggested that HBV infection of peripheral blood mononuclear cells could be a cofactor implicated in the development of immunodeficiency due to HIV. For this reason we have investigated the presence of HBV-DNA in peripheral blood mononuclear cells by in situ hybridization. Although its detection was more frequent in anti-HIV positive patients than in anti-HIV negative ones (p < 0.05), it was not related to clinical state of immunodeficiency. With regard to serological HBV markers, HBV-DNA was detected in peripheral blood mononuclear cells from antiHBc w/o antiHBs patients. This fact means the virus may persist in this cells after recovery and suggest they could serve as additional reservoirs of HBV. These cells, that contain the HBV genome, could be implicated in the perpetuation, reactivation of the infection and in its transmission.

Detection of hepatitis B virus DNA in chronic carriers by the polymerase chain reaction.

The polymerase chain reaction (PCR) was used to detect hepatitis B virus DNA (HBV-DNA) in serum samples of 104 chronic HBV carriers. Of 22 patients positive for both HBV surface (HBsAg) and HBVe (HBeAg) antigens, seven were positive for HBV-DNA on dot blot hybridisation, and all 22 positive in the PCR. Of 41 HBsAg positive patients who had antibodies against HBeAg (anti-HBe), only three were positive for DNA-HBV on dot blot hybridisation, however DNA was detected in 30 of them with the PCR. Similarly, of 41 individuals with antibodies against HBsAg (anti-HBs), 23 yielded positive results in the PCR technique, although dot blot hybridisation detected HBV-DNA in only one patient. These results indicate that while serological and conventional DNA hybridisation assays are not sensitive enough to determine the infectivity of HBV chronic carriers, PCR is an accurate method for establishing the status and progression of disease in these patients.

[Detection of hepatitis B virus DNA in peripheral blood mononuclear cells from patients with various hepatopathies using in situ hybridization]. / Detección del DNA del virus de la hepatitis B en células mononucleares de sangre periférica de pacientes con distintas hepatopatías mediante hibridación "in situ".

We have investigated, by "in situ" hibridisation, the presence of hepatitis B virus (HBV) DNA in peripheral blood mononuclear cells (PBMC) from 45 patients with acute and chronic hepatic disorders directly related with HBV or with some seric HBV marker. Results has been related with serological markers and the different types of hepatopaties. The HBV-DNA was detected in PBMC more frequently in patients with hepatic alterations more prolongated (chronic active hepatitis, chronic persistent hepatitis and cirrhosis) than in acute hepatitis patients. It was not detected in any asymptomatic patient with HBV serological markers. As regards HBV serological markers, HBV-DNA was detected in PBMC in 8/11 HBsAg positive patients and in 11/34 HBsAg negative patients: 3 antiHBc positive, 5 antiHBc and antiHBs positive and 3 without conventional seric markers. The detection of HBV-DNA in antiHBc and/or antiHBs positive subjects means the virus may persist after recovery of infection and suggests PMBC could serve as additional reservoirs for reinfection of hepatocytes leading to a reactivation of the liver disease. Our results suggest that HBV infection of PBMC is a frequent event during HBV infection and can have important consequences fundamentally with respect to pathogenic mechanisms of HBV induced liver disease and to the transmission of the virus.

[Detection and antigenic distribution of hepatitis B virus in liver tissue and its relation to other serological markers of viral replication]. / Detección y distribución antigénica del virus de la hepatitis B en tejido hepático y su relación con otros marcadores serológicos de replicación viral.

The aim of this work has been the production of specific monoclonal antibodies against HBV-antigens and their utilisation in order to study their distribution on liver tissue. The monoclonal antibodies anti-HBc and anti-HBs were obtained by the modified hybridoma technique. This study was performed on 50 patients affected by several chronic hepatopathies. For the detection of the antigens, avidin-biotin-peroxidase complex immunostaining was used. Both cytoplasmic and membranous HBsAg were detected in 15 out of 16 HBsAg+ patients; 8 of 12 HBsAg-/anti-HBc+ patients and 1 HBsAg-/antiHBc- patient. Cytoplasmic and nuclear HBcAg was observed in 12 of 16 HBsAg+ patients and 4 of 20 HBsAg- patients. Although the presence of serum HBsAg is an index of liver infection, in some HBsAg-/antiHB+ patients (20%) with undetectable levels of HBsAg, hepatic injury may be disclosed by the detection of other markers of active viral replication.

[Presence of HBsAg in lymphocyte cultured from patients infected with human immunodeficiency virus (HIV)]. / Presencia de HBsAg en cultivos de linfocitos de pacientes infectados por el virus de la inmunodeficiencia humana (VIH).

The behavior of the hepatitis B virus was investigated in mononuclear cell cultures in nine patients infected by the human immunodeficiency virus. Although only one of them was a carrier of HBsAg and four had anti-HBs in their sera, HBsAg was detected in the supernatant of the cultures from all patients. These results suggest that mononuclear cells might act as a reservoir for hepatitis B virus, and that the concomitant infection by this virus and human immunodeficiency virus may alter the natural evolution of any of both conditions.

[Detection of human immunodeficiency virus in seronegative adults]. / Detección del virus de la inmunodeficiencia humana en adultos seronegativos.

The diagnosis of human immunodeficiency virus infection is sometimes difficult or nonspecific, both in early and late stages, as the patients may be seronegative at the time of testing. Although serologic testing usually suffices to identify infected individuals and to follow up the course of the infection, in some cases direct detection of the virus is required. The culture of the mononuclear cells of the patient permits, after stimulation with mitogens and interleukin-2, the expression of viral antigens even in asymptomatic patients with latent or apparently nonproductive infection. In this way we have recovered the virus in four patients without serological evidence of infection. The possibility that human immunodeficiency virus infection can be undetectable with the usual diagnostic techniques, at least in a small proportion of patients, supports the need to use other methods such as direct viral culture to permit the identification of a greater number of infected individuals and the adoption of the appropriate prophylactic or therapeutic measures.