Ocular manifestations of leishmaniasis in a cat: first case report from Brazil

ABSTRACT An 8-year-old domestic short hair female cat initially presented with bilateral uveitis with pseudotumoral appearance. The patient tested negative for feline immunodeficiency virus (FIV), feline leukemia virus (FeLV) and Toxoplasma gondii. Histopathology of a granulomatous lesion on the upper left conjunctiva revealed amastigotes compatible with Leishmania spp. Aqueous humor was aspired and the diagnosis was confirmed after isolation of promastigotes cultivated in biphasic NNN medium and by positive polymerase chain reaction (PCR) for Leishmania infantum. Treatment with allopurinol (10mg/kg/ BID/PO) was commenced and a natural insect repellent was prescribed. Six months of treatment with allopurinol associated with the initial topical medications helped to improve ocular signs. Leishmaniasis should be considered as a differential diagnosis in cats presenting uveitis with pseudotumoral appearance. To our knowledge, this is the first report of feline leishmaniasis with ocular manifestation in Brazil, in which diagnosis was confirmed by aqueous humor analysis.

Impacto do grau de uveíte em diferentes tipos de úlceras de córneas em cães submetidos ao enxerto pediculado de conjuntiva bulbar - 34 casos

RESUMO O presente trabalho objetivou avaliar os resultados de 34 olhos submetidos ao enxerto conjuntival pediculado (ECP) em ceratites ulcerativas profundas (n=5), em ceratites ulcerativas com colagenólise (n=2), descemetocele (n=7), perfuração corneal (n=15) e prolapso de íris (n=5). Os impactos do grau de uveíte e da integridade da córnea foram correlacionados com presença e ausência de visão por tabelas de contingência. Raças braquicefálicas foram acometidas em 91,11% dos casos. O número de córneas consideradas perfuradas [20/34 (58,82%)] foi maior que o de córneas íntegras [14/34 (41,17%)]. Ao 50º dia de pós-operatório, o número de olhos visuais que apresentavam córneas íntegras previamente às cirurgias (n=13) não diferiu significativamente dos olhos com córneas perfuradas (n=12) (P=0,05). Avaliações relativas ao grau de uveíte, revelaram que a metade dos casos foi considerada severa [17/34 (50%)] e na outra metade as uveítes foram consideradas discretas. Dos 17 casos que apresentaram uveíte severa, oito recuperaram a visão. Já nos 17 olhos onde a uveíte foi considerada leve, 15 mantiveram a visão ao final do período de avaliação. Apesar de a integridade da córnea não se correlacionar com a severidade da uveíte (P=0,48), constatou-se que o número de olhos visuais com uveíte discreta foi significativamente maior que os olhos com uveíte severa (P=0,006). Neste estudo, a taxa geral de sucesso visual após ECP foi de 73,52% e a integridade da córnea não exerceu impacto significativo sobre a manutenção da visão. Todavia, olhos acometidos por uveítes severas apresentaram menor chance de recuperar a visão.

Development of a novel lateral flow assay for detection of African swine fever in blood

Background

African swine fever (ASF) is a viral infectious disease of domestic and wild suids of all breeds and ages, causing a wide range of hemorrhagic syndromes and frequently characterized by high mortality. The disease is endemic in Sub-Saharan Africa and Sardinia. Since 2007, it has also been present in different countries of Eastern Europe, where control measures have not been effective so far. The continued spread poses a serious threat to the swine industry worldwide. In the absence of vaccine, early detection of infected animals is of paramount importance for control of the outbreak, to prevent the transmission of the virus to healthy animals and subsequent spreading of the disease. Current laboratory diagnosis is mainly based on virological methods (antigen and genome detection) and serodiagnosis.

Results

In the present work, a Lateral Flow Assay (LFA) for antigen detection has been developed and evaluated. The test is based on the use of a MAb against VP72 protein of ASFV, the major viral capsid protein and highly immunogenic. First experiments using VP72 viral and recombinant protein or inactivated culture virus showed promising results with a sensitivity similar to that of a commercially available Antigen-ELISA. Moreover, these strips were tested with blood from experimentally infected pigs and field animals and the results compared with those of PCR and Antigen-ELISA. For the experimentally infected samples, there was an excellent correlation between the LFA and the ELISA, while the PCR always showed to be more sensitive (38 % positive samples by PCR versus 27 % by LFA). The LFA was demonstrated to be positive for animals with circulating virus levels exceeding 10⁴ HAU. With the field samples, once again, the PCR detected more positives than either the Antigen-ELISA or LFA, although here the number of positive samples scored by the LFA exceeded the values obtained with the Antigen-ELISA, showing 60 % positivity vs 48 % for the ELISA. For the two groups of sera, the specificity was close to 100 % indicating that hardly any false positive samples were found.

Conclusions

The newly developed LFA allows rapid and reliable detection of ASFV, at field and laboratory level, providing a new useful tool for control programs and in situations where laboratory support and skilled personnel are limited.

The conserved carboxyl domain of MorC, an inner membrane protein of Aggregatibacter actinomycetemcomitans, is essential for membrane function

Morphogenesis protein C (MorC) of Aggregatibacter actinomycetemcomitans is important for maintaining the membrane morphology and integrity of the cell envelope of this oral pathogen. The MorC sequence and operon organization were found to be conserved in Gammaproteobacteria, based on a bioinformatic analysis of 435 sequences from representative organisms. Functional conservation of MorC was investigated using an A. actinomycetemcomitans morC mutant as a model system to express MorC homologs from four phylogenetically diverse representatives of the Gammaproteobacteria: Haemophilus influenzae, Escherichia coli, Pseudomonas aeruginosa, and Moraxella catarrhalis. The A. actinomycetemcomitans strains expressing the homologous proteins were assessed for sensitivity to bile salts, leukotoxin secretion, autoaggregation and membrane morphology. MorC from the most closely related organism (H. influenzae) was functionally identical to MorC from A. actinomycetemcomitans. However, the genes from more distantly related organisms restored some but not all A. actinomycetemcomitans mutant phenotypes. In addition, deletion mutagenesis indicated that the most conserved portion of the protein, the C-terminus DUF490 domain, was necessary to maintain the integrity of the membrane. Deletion of the last 10 amino acids of this domain of the A. actinomycetemcomitans MorC protein was sufficient to disrupt membrane stability and leukotoxin secretion. The data suggest that the MorC sequence is functionally conserved across Gammaproteobacteria and the C-terminus of the protein is essential for maintaining membrane physiology.

Use of Phosphite Salts in Laboratory and Semicommercial Tests to Control Citrus Postharvest Decay

Potassium phosphite (KP) concentrations that inhibited the germination of 50% of Penicillium digitatum conidia were 229, 334, 360, 469, 498, or 580 mg/liter at pH 3, 4, 5, 6, 7, or 8, respectively. Increasing phosphate content in media reduced phosphite toxicity. To control green or blue mold, fruit were inoculated with P. digitatum or P. italicum, then immersed 24 h later in KP, calcium phosphite (CaP), sodium carbonate, sodium bicarbonate, or potassium sorbate for 1 min at 20 g/liter for each at 25 or 50°C. Mold incidence was lowest after potassium sorbate, CaP, or KP treatments at 50°C. CaP was often more effective than KP but left a white residue on fruit. KP was significantly more effective when fruit were stored at 10 or 15°C after treatment compared with 20°C. Acceptable levels of control were achieved only when KP was used in heated solutions or with fungicides. KP was compatible with imazalil (IMZ) and other fungicides and improved their effectiveness. KP increased thiabendazole or IMZ residues slightly. Phosphite residues did not change during storage for 3 weeks, except they declined when KP was applied with IMZ. KP caused no visible injuries or alteration in the rate of color change of citrus fruit in air or ethylene at 5 μl/liter.

Experimental study of vertical stress profiles of a confined granular bed under static and dynamic conditions

In a wet agglomeration process inside a low shear mixer, the blade function is to induce i) homogenization of the liquid sprayed on the powder surface and ii) a stress field able to transfer the mechanical energy at the particle scale. In this work we study the mechanical state of a confined powder bed through the analysis of stress distributions (by force measurements) in a rectangular cell in two cases: for a classical model powder (i.e. glass beads) and a complex powder (i.e. wheat semolina). Two types of vertical stress profiles are obtained according to the type of measurements carried out in the powder bed, either locally (at different positions in the cell) or globally (at the entire base). The global vertical stress profile follows Janssen's model and the local vertical stress profile highlights a critical length, identified as the percolation threshold of the force network, and a shielding length near the bottom, which is similar to an influence length of the side walls. In the context of wet agglomeration, the results allow to consider the role of the characteristic lengths in the mixing bowl under vertical mechanical solicitation.

Characterization of the secretion pathway of the collagen adhesin EmaA of Aggregatibacter actinomycetemcomitans

The extracellular matrix protein adhesin A (EmaA) surface antennae-like structures of the periodontal pathogen Aggregatibacter actinomycetemcomitans are composed of three identical protein monomers. Recently, we have demonstrated that the protein is synthesized with an extended signal peptide of 56 amino acids necessary for membrane targeting and protein translocation. In this study, EmaA secretion was demonstrated to be reliant on a chaperone-dependent secretion pathway. Deletion of secB partially reduced but did not abolish the amount of EmaA in the membrane. This observation was attributed to an increase in the synthesis of DnaK in the ΔsecB strain. Overexpression of a DnaK substitution mutant (A174T), with diminished activity, in the ΔsecB strain further reduced the amount of EmaA in the membrane. Expression of dnaK A174T in the wild-type strain did not affect the amount of EmaA in the membrane when grown under optimal growth conditions at 37°C. However, EmaA was found to be reduced when this strain was grown at heat-shock temperature. A chromosomal deletion of amino acids 16-39 of the EmaA extended signal peptide, transformed with either the wild-type or dnaK A174T-expressing plasmid, did not affect the amount of EmaA in the membrane. In addition, the level of EmaA in a ΔsecB/emaA(-) double mutant strain expressing EmaAΔ16-39 was unchanged when grown at both temperatures. The data suggest that chaperones are required for the targeting of EmaA to the membrane and a specific region of the signal peptide is necessary for secretion under stress conditions.

3D Reconstruction of a Subcomplex of NADH-ubiquinone-oxidoreductase (Complex I) from Yarrowia lipolytica

Extended abstract of a paper presented at Microscopy and Microanalysis 2011 in Nashville, Tennessee, USA, August 7–August 11, 2011.

The structure of eukaryotic and prokaryotic complex I

The structures of the NADH dehydrogenases from Bos taurus and Aquifex aeolicus have been determined by 3D electron microscopy, and have been analyzed in comparison with the previously determined structure of Complex I from Yarrowia lipolytica. The results show a clearly preserved domain structure in the peripheral arm of complex I, which is similar in the bacterial and eukaryotic complex. The membrane arms of both eukaryotic complexes show a similar shape but also significant differences in distinctive domains. One of the major protuberances observed in Y. lipolytica complex I appears missing in the bovine complex, while a protuberance not found in Y. lipolytica connects in bovine complex I a domain of the peripheral arm to the membrane arm. The structural similarities of the peripheral arm agree with the common functional principle of all complex Is. The differences seen in the membrane arm may indicate differences in the regulatory mechanism of the enzyme in different species.

Interleukin-12 gene polymorphisim in patients with giant cell arteritis, polymyalgia rheumatica and elderly-onset rheumatoid arthritis

OBJECTIVE

The cytokine profile suggests that giant cell arteritis (GCA) is a Th1-driven disease, in which local IFN-gamma plays a critical role in the development of a systemic arteritis. IL-12 is a potent inducer of IFN-gamma and is critically involved in biasing an immune response towards a Th1 pathway. The purpose of this study was to investigate whether there was an association between an IL-12 gene polymorphism (-1188 A/C 3UTR) and disease susceptibility for GCA and two other age-related inflammatory conditions, such as polymyalgia rheumatica (PMR) and elderly-onset rheumatoid arthritis (EORA). Furthermore, we attempted to correlate such polymorphism with in vitro IL-12 production.

MATERIALS AND METHODS

We analyzed genotypes at -1188 in the 3UTR of the IL-12 promoter by PCR-RFLP in 68 GCA, 138 PMR, and 72 EORA patients as well as in 465 healthy controls (HC). IL-12p70 levels in culture supernatants after stimulation with PMA+Ionomycin was assessed by ELISA.

RESULTS

All groups were in Hardy-Weinberg equilibrium. Allelic and gen-omic distribution was not significantly different among the study groups. None of the genetic variants was associated with disease severity. Although the differences were not statistically significant, HC genotypes were associated with distinct IL-12 p70 production.

CONCLUSIONS

The IL-12 (-1188 A/C 3UTR) gene polymorphism is not associated with disease susceptibility or severity in three age-related chronic inflammatory syndromes. The production of IL-12 p70 is dependent on the genetic background in HC, although in patients such association may be biased by other unknown factors.

Twin product/process approach for pellet preparation by extrusion/spheronisation

The extrusion/spheronisation technique has made a notable contribution to the existing range of pharmaceutical forms especially in the area of modified-release products. The twin product/process approach adopted in this work is based on the on-line monitoring of the hydro-textural characteristics of the product up to its final form. The objective is to balance the influence of the operating parameters for each successive stage against the influence of product characteristics. A coherent "representational framework" is proposed for insoluble substances through a diagram locating intergranular porosity value depending on water content. The wetting/kneading operation brings the material to a state in which porosity is linked to water content. The extrusion operation densifies the material to saturation point, while spheronisation is only a shaping process which maintains hydro-textural state. The drying operation finalises the textural characteristics of the product by densifying the medium through induced shrinkage.

The three-dimensional structure of complex I from Yarrowia lipolytica: a highly dynamic enzyme

The structure of complex I from Yarrowia lipolytica was determined by three-dimensional electron microscopy. A random conical data set was collected from deep stain embedded particles. More than 14000 image pairs were analyzed. Through extensive classification combined with three-dimensional reconstruction, it was possible for the first time to show a much more detailed substructure of the complex. The peripheral arm is subdivided in at least six domains. The membrane arm shows two major protrusions on its matrix facing side and exhibits a channel like feature on the side facing the cytoplasm. Structures resembling a tether connecting the subunits near the catalytic center with the protrusions of the membrane arm provide a second connection between matrix and membrane domain.

Nutritional assessment, health markers and lipoprotein profile in postmenopausal women belonging to a closed community

OBJECTIVE

To assess the dietary characteristics of a closed community and their relationship with several health markers and lipid and lipoprotein values in postmenopausal women.

DESIGN

Energy and nutrient intake, serum lipids, lipoproteins, antioxidants, peroxides and low-density lipoprotein (LDL) peroxides in addition to several health markers were measured in a closed, postmenopausal female community consuming a diet without meat, meat products and alcoholic beverages.

SETTING

Departamento de Nutrición and Sección Departamental de Química Analítica and Escuela de Especialización de Análisis Clínicos, Universidad Complutense de Madrid, Spain and Lerma, Burgos, Spain.

RESULTS

Cereals, vegetables, legumes and fruit, together with milk and eggs, constituted the most important ingredients of the diet consumed. Dietary carbohydrates contributed 42%en and lipids 46.4%en. The SFA/MUFA/PUFA ratio was 1/2/1 and the n-3/n-6 ratio 0.05 (SFA=saturated fatty acids, MUFA=monounsaturated fatty acids, PUFA=polyunsaturated fatty acids). The study community diet was monotonous and made for possible deficiencies of iron, magnesium, zinc, vitamin B(6) and vitamin D, in variable proportions. Routine biochemical and haematological normality markers indicate that only one woman presented hyperglycaemia and hyperuricaemia. Two women had haemoglobin levels <12 g/dl, but their mean corpuscular volume or mean corpuscular haemoglobin was normal. The prevalence of high cholesterol values (>6.21 mmol/l) was 42.8%, while that of high LDL-cholesterol levels (>3.88 mmol/l) was 35.7%, but none of the women displayed levels of high-density lipoprotein (HDL)-cholesterol <1.16 mmol/l, triglycerides >1.2 mmol/l or an LDL-cholesterol/HDL-cholesterol ratio>3. Only one woman had apolipoprotein (Apo) B levels >1.5 g/l, while most of the women presented Apo B values <1.2 g/l and an ApoA-1/ApoB ratio &<1.1. Plasma and LDL-peroxide levels, together with the tocopherol and carotene intakes, suggest a good antioxidant status in this population.

CONCLUSIONS

The diet of the study group seems compatible with a healthy life-profile and permits a more-than-acceptable degree of cardiovascular disease protection. However, the consumption of certain nutrients should be improved.

The first three-dimensional structure of phosphofructokinase from Saccharomyces cerevisiae determined by electron microscopy of single particles

Phosphofructokinaseis a key regulatory enzyme of the glycolytic pathway. We have determined the structure of this enzyme from Saccharomyces cerevisiae to a resolution of 2.0 nm. This is the first structure available for this family of enzymes in eukaryotic organisms. Phosphofructokinase is an octamer composed of 4alpha and 4beta subunits arranged in a dihedral point group symmetry D(2). The enzyme has a very open and elongated structure, with dimensions of 24 nm in length and 17 nm in width. The final structure, calculated from 0 degrees tilt projections of the molecule at random orientations using as reference the volume obtained by the random conical reconstruction technique in ice, has allowed us to discern the shapes of the subunits and their mutual arrangement in the octamer.

Cloning and sequence analysis of the LEU2 homologue gene from Pichia anomala

The Pichia anomala LEU2 gene (PaLEU2) was isolated by complementation of a leu2 Saccharomyces cerevisiae mutant. The cloned gene also allowed growth of a Escherichia coli leuB mutant in leucine-lacking medium, indicating that it encodes a product able to complement the beta-isopropylmalate dehydrogenase deficiency of the mutants. The sequenced DNA fragment contains a complete ORF of 1092 bp, and the deduced polypeptide shares significant homologies with the products of the LEU2 genes from S. cerevisiae (84% identity) and other yeast species. A sequence resembling the GC-rich palindrome motif identified in the 5' region of S. cerevisiae LEU2 gene as the binding site for the transcription activating factor encoded by the LEU3 gene was found at the promoter region. In addition, upstream of the PaLEU2 the 3'-terminal half of a gene of the same orientation, encoding a homologue of the S. cerevisiae NFS1/SPL1 gene that encodes a mitochondrial cysteine desulphurase involved in both tRNA processing and mitochondrial metabolism, was found. The genomic organization of the PaNFS1-PaLEU2 gene pair is similar to that found in several other yeast species, including S. cerevisiae and Candida albicans, except that in some of them the LEU2 gene appears in the reverse orientation.

Some predictors of cardiovascular mortality among the elderly population of Botucatu (SP)

OBJECTIVE

To detect factors associated with cardiovascular mortality in the elderly of Botucatu.

METHODS

We evaluated 29 variables of interest in a cohort of patients aged 60 using data from a survey conducted between 1983/84. The elderly cohort was analyzed in 1992 to detect the occurrence of cardiovascular deaths. Survival analysis was performed using the Kaplan-Meier method, the log-rank test, and Cox regression analysis. Three models were adapted for each group of variables, and a final model was chosen from those variables selected from each group.

RESULTS

We identified predictor for cardiovascular death according to age for elderly males not supporting the family, not possessing a vehicle, and previous cardiovascular disease. In elderly females, the predictor variables were previous cardiovascular disease and diabetes mellitus.

CONCLUSION

Socioeconomic indicators (family heading and vehicle ownership) may be added to well stabilished medical factors (diabete mellitus and hypertension to select target groups for programs intended to reduce deaths due to cardiovascular diseases in elderly people.

Analysis of a putative voltage-gated prokaryotic potassium channel

Most of the completely sequenced prokaryotic genomes contain genes of potassium channel homologues, but there is still not much known about the role of these proteins in prokaryotes. Here we describe the large-scale overproduction and purification of a prokaryotic voltage-gated potassium channel homologue, Kch, from Escherichia coli. After successful overproduction of the protein, a specific increase in the potassium permeability of the cells was found. Kch could be purified in large amounts using classical purification methods to prevent aggregation of the protein. The physiological state of the protein was revealed to be a homotetramer and the protein was shown to be localized to the cytoplasmic membrane of the cells. In the course of the localization studies, we found a specific increase in the density of the cytoplasmic membrane on Kch production. This was linked to the observed increase in the protein to lipid ratio in the membranes. Another observed change in the membrane composition was an increase in the cardiolipin to phosphatidylglycerol ratio, which may indicate a specific cardiolipin requirement of Kch. On the basis of some of our results, we discuss a function for Kch in the maintenance of the membrane potential in E. coli.

Two-dimensional structure of the native light-harvesting complex LH2 from Rubrivivax gelatinosus and of a truncated form

The light-harvesting complex LH2 of Rubrivivax gelatinosus has an oligomeric structure built from alpha-beta heterodimers containing three bacteriochlorophylls and one carotenoid each. The alpha subunit (71 residues) presents a C-terminal hydrophobic extension (residues 51-71) which is prone to attack by an endogenous protease. This extension can also be cleaved by a mild thermolysin treatment, as demonstrated by electrophoresis and by matrix-assisted laser desorption-time of flight mass spectrometry. This cleavage does not affect the pigment binding sites as shown by absorption spectroscopy. Electron microscopy was used to investigate the structures of the native and thermolysin cleaved forms of the complexes. Two-dimensional crystals of the reconstituted complexes were examined after negative staining and cryomicroscopy. Projection maps at 10 A resolution were calculated, demonstrating the nonameric ring-like organization of alpha-beta subunits. The cleaved form presents the same structural features. We conclude that the LH2 complex is structurally homologous to the Rhodopseudomonas acidophila LH2. The hydrophobic C-terminal extension does not fold back in the membrane, but lays out on the periplasmic surface of the complex.

The structure of the V(1)-ATPase determined by three-dimensional electron microscopy of single particles

We determined the structure of the V(1)-ATPase from Manduca sexta to a resolution of 1.8 nm, which for the first time reveals internal features of the enzyme. The V(1)-ATPase consists of a headpiece of 13.5 nm in diameter, with six elongated subunits, A(3) and B(3), of approximately equal size, and a stalk of 6 nm in length that connects V(1) with the membrane-bound domain, V(O). At the center of the molecule is a cavity that extends throughout the length of the A(3)B(3) hexamer. Inside the cavity the central stalk can be seen connected to only two of the catalytic A subunits. The structure was obtained by a combination of the Random Conical Reconstruction Technique and angular refinements. Additional recently developed techniques that were used include methods for simultaneous translational rotational alignment of the 0 degrees images, contrast transfer function correction for tilt images, and the Two-Step Radon Inversion Algorithm.

Structural and functional effects of hydrostatic pressure on centrosomes from vertebrate cells

In an attempt to better understand the role of centrioles in vertebrate centrosomes, hydrostatic pressure was applied to isolated centrosomes as a means to disassemble centriole microtubules. Treatments of the centrosomes were monitored by analyzing their protein composition, ultrastructure, their ability to nucleate microtubules from pure tubulin, and their capability to induce parthenogenetic development of Xenopus eggs. Moderate hydrostatic pressure (95 MPa) already affected the organization of centriole microtubules in isolated centrosomes, and also impaired microtubule nucleation. At higher pressure, the protein composition of the peri-centriolar matrix (PCM) was also altered and the capacity to nucleate microtubules severely impaired. Incubation of the treated centrosomes in Xenopus egg extract could restore their capacity to nucleate microtubules after treatment at 95 MPa, but not after higher pressure treatment. However, the centriole structure was in no case restored. It is noteworthy that centrosomes treated with mild pressure did not allow parthenogenetic development after injection into Xenopus eggs, even if they had recovered their capacity to nucleate microtubules. This suggested that, in agreement with previous results, centrosomes in which centriole architecture is impaired, could not direct the biogenesis of new centrioles in Xenopus eggs. Centriole structure could also be affected by applying mild hydrostatic pressure directly to living cells. Comparison of the effect of hydrostatic pressure on cells at the G1/S border or on the corresponding cytoplasts suggests that pro-centrioles are very sensitive to pressure. However, cells can regrow a centriole after pressure-induced disassembly. In that case, centrosomes eventually recover an apparently normal duplication cycle although with some delay.

Expression of Pichia anomala INV1 gene in Saccharomyces cerevisiae results in two different active forms of hypoglycosylated invertase

The Pichia anomala invertase gene (INV1) was introduced at different copy numbers into a sucrose-nonfermenting mutant of Saccharomyces cerevisiae and expressed from its own promoter sequences. The level reached in the production of invertase by the transformants (up to 540 units/10(10) cells) was in agreement with the INV1 gene dosage. Two forms of multimeric active and glycosylated invertase displaying different subcellular locations and molecular masses could be detected in the transformants. One was found to be present in the culture medium and in the periplasm, and the other could only be detected inside the cell. Each of the two heterologous forms of invertase was shown to be an oligomer composed of identical subunits. The difference found in the apparent molecular masses of their monomers (81.5 and 78.3 kDa, respectively) seems to be due to the size of their N-linked oligosaccharide chains (on average 2.4 and 1.9 kDa, respectively), since the number of sugar chains (9) and the molecular mass of the protein moiety (60.5 kDa) are identical in both forms. The shorter size of their oligosaccharides must also be the reason for the lower apparent molecular masses of the heterologous invertases when compared with the enzyme purified from P. anomala. The hypoglycosylated invertase accumulated within the cells of the transformants to an unusual level (up to 130 units/10(10) cells). Such accumulation of active enzyme inside the cells, as well as its underglycosylation, could be due to intrinsic properties of the P. anomala invertase that are determined by the particular primary structure of its protein moiety.

Three-dimensional structure and subunit topology of the V(1) ATPase from Manduca sexta midgut

The three-dimensional structure of the Manduca sexta midgut V(1) ATPase has been determined at 3.2 nm resolution from electron micrographs of negatively stained specimens. The V(1) complex has a barrel-like structure 11 nm in height and 13.5 nm in diameter. It is hexagonal in the top view, whereas in the side view, the six large subunits A and B are interdigitated for most of their length (9 nm). The topology and importance of the individual subunits of the V(1) complex have been explored by protease digestion, resistance to chaotropic agents, MALDI-TOF mass spectrometry, and CuCl(2)-induced disulfide formation. Treatment of V(1) with trypsin or chaotropic iodide resulted in a rapid cleavage or release of subunit D from the enzyme, indicating that this subunit is exposed in the complex. Trypsin cleavage of V(1) decreased the ATPase activity with a time course that was in line with the cleavage of subunits B, C, G, and F. When CuCl(2) was added to V(1) in the presence of CaADP, the cross-linked products A-E-F and B-H were generated. In experiments where CuCl(2) was added after preincubation of CaATP, the cross-linked products E-F and E-G were formed. These changes in cross-linking of subunit E to near-neighbor subunits support the hypothesis that these are nucleotide-dependent conformational changes of the E subunit.

Molecular architecture of Manduca sexta midgut V1 ATPase visualized by electron microscopy

The structure of the V1 ATPase from the tobacco hornworm Manduca sexta has been determined from electron micrographs of isolated, negatively stained specimens. The resulting images clearly show a pseudohexagonal arrangement of six equal-sized protein densities, presumably representing the three copies each of subunits A and B, which comprise the headpiece of the enzyme. A seventh density could be observed either centrally or asymmetrically to the hexamer. The maximum diameter of the V1 complex in the hexagonal projection is 13 nm with each of the six peripheral densities being 3-4 nm in diameter.

Effects of calcium and nucleotides on the structure of insect flight muscle thin filaments

The structure of the insect flight muscle thin filament has been studied using a Drosophila mutant (Ifm(2)2) which does not contain thick filaments. Thin filaments that are biochemically identical to those of the wild type can be isolated free from thick filament contamination. We show that isolated thin filaments have different symmetries depending upon the calcium concentration. While the filaments mainly contain 13 subunits in six turns of the 5.9 nm genetic helix in the absence of calcium, 50% of the filaments have 28 subunits in 13 turns of the genetic helix at calcium concentrations equivalent to those present during muscle contraction. We also show that the structure (mainly the helical order) of the thin filaments depends on the nature of the nucleotide bound to the actin monomers. Three-dimensional reconstructions of the thin filaments in the presence and absence of calcium show that tropomyosin moves between two different positions on the actin filament. However, in Drosophila the amplitude of the movement as well as the disorder in the positions of the components (tropomyosin, troponin complex) are larger than those generally observed in other species.

Endothelium-derived nitric oxide-dependent response to hypoxia in piglet intrapulmonary arteries

The purpose of this study was to determine the involvement of eicosanoids and nitric oxide (NO) in the response to hypoxia in isolated intrapulmonary (third branch) arteries from 10- to 17-day-old piglets. We also compared the response to hypoxia in pulmonary arteries to pulmonary veins, mesenteric arteries and coronary arteries. Hypoxia was generated in vascular rings (under resting force or precontracted with 30 mM KCl) by switching the gas aerating the organ chambers from one composed of 21% O2-5% CO2-balance N2 (pO2 145 +/- 1.27 mm Hg) to a mixture of 5% CO2-balance N2 (pO2 33.87 +/- 0.24 mm Hg). In precontracted rings hypoxia produced a transient vasoconstriction (26 +/- 8% of the precontraction value) reaching a peak in 3-4 min, followed by a relaxation. A similar pattern of response was observed in pulmonary veins, coronary arteries and mesenteric arteries. The contractile phase was not present in endothelium-denuded arteries or after incubation with the NO synthase inhibitor L-NAME (10(-4) M) or the guanylate cyclase inhibitor methylene blue (10(-5) M). No changes in the hypoxia-induced vasoconstriction were observed after preincubation with the NO precursor L-arginine (10(-5) M), the lipoxygenase inhibitor meclofenamate (10(-5) M), the cyclooxygenase inhibitor AA 861 (10(-5) M), or the cytochrome P450 oxidase inhibitor SKF 525A (10(-5) M). These findings demonstrate that the contractile response to hypoxia in the isolated intrapulmonary porcine artery is caused by the loss of the inhibitory effects of endothelium-derived NO on the vascular tone. Eicosanoids do not appear to be involved in this response. Since the response to hypoxia in isolated rings is not specific to pulmonary vessels, any correlation between this response and hypoxic pulmonary vasoconstriction should be avoided.

In vitro effects of magnesium sulfate in isolated intrapulmonary and mesenteric arteries of piglets

Magnesium sulfate (MgSO4) has been proposed to be an efficient treatment in persistent pulmonary hypertension of the newborn. We compared the ability of MgSO4 to inhibit the responses to several vasoconstrictors in isolated intrapulmonary and mesenteric arteries from 10-17-d-old piglets. MgSO4 (3-100 mM) produced a slight vasodilator effect in pulmonary arteries precontracted with the thromboxane A2 mimetic U46619 (10(-6) M), noradrenaline (10(-5) M), and KCl (80 mM) (15.1 +/- 3.7%; 20 +/- 3.33%; 10.4 +/- 0.9% at 100 mM MgSO4 respectively). In contrast, in mesenteric arteries MgSO4, produced a marked vasodilation (80.4 +/- 4.0%, 93.1 +/- 3.46%, and 87.5 +/- 1.93% at 100 mM MgSO4, respectively, p < 0.01 versus pulmonary arteries). The vasodilator effect of MgSO4 was endothelium-independent and reversed by increasing the extracellular Ca2+ concentration. After incubation for 1 h of pulmonary arteries with three different MgSO4 concentrations (0, 1.2, and 4.8 mM) there were no differences in the contractile responses to U46619 nor in the vasodilator effects of acetylcholine or sodium nitroprusside. Rapid removal of Mg2+ from bath medium produced a transient vasodilation which was more marked in pulmonary than in mesenteric arteries and was greatly reduced by the removal of endothelium or by the nitric oxide synthase inhibitor L-NAME (10(-4) M). We conclude that MgSO4 is a poor vasodilator of pulmonary arteries in vitro and at physiologic concentrations appears to inhibit nitric oxide release from the pulmonary endothelium. Thus, the possible beneficial clinical effects of MgSO4 in persistent pulmonary hypertension of the newborn do not seem to be related to a direct effect on pulmonary vascular smooth muscle.

Cloning and sequence analysis of the invertase gene INV 1 from the yeast Pichia anomala

A genomic library from the yeast Pichia anomala has been constructed and employed to clone the gene encoding the sucrose-hydrolysing enzyme invertase by complementation of a sucrose non-fermenting mutant of Saccharomyces cerevisiae. The cloned gene, INV1, was sequenced and found to encode a polypeptide of 550 amino acids which contained a 22 amino-acid signal sequence and ten potential glycosylation sites. The amino-acid sequence shows significant identity with other yeast invertases and also with Kluyveromyces marxianus inulinase, a yeast beta-fructofuranosidase which has a different substrate specificity. The nucleotide sequences of the 5' and 3' non-coding regions were found to contain several consensus motifs probably involved in the initiation and termination of gene transcription.

Group B Streptococcus and E. coli LPS-induced NO-dependent hyporesponsiveness to noradrenaline in isolated intrapulmonary arteries of neonatal piglets

1. The effects of endotoxin (E. coli lipopolysaccharide, LPS) and heat inactivated group B Streptococcus (GBS) were studied on the contractile responses to noradrenaline (NA) in isolated pulmonary arteries and on the activity of the constitutive and inducible nitric oxide synthase (NOS) in lung fragments of neonatal piglets. 2. Short-term (< or = 5 h) incubation with LPS (1 micrograms ml-1) or GBS (3 x 10(7) colonies forming units ml-1) did not modify the vascular responsiveness to NA (10(-8) M-10(-4) M) in isolated intrapulmonary arteries. However, long-term incubation (20 h) with LPS or GBS produced a significant reduction in the maximal contractile responses and shifted the concentration-response curve for NA downwards. 3. Endothelium removal or the cyclo-oxygenase inhibitor meclofenamate (10(-5) M) did not affect the GBS- and LPS-induced hyporesponsiveness to NA. 4. The presence of the nitric oxide (NO) precursor, L-arginine (10(-5) M), 30 min prior to the contractility challenge increased the LPS- and GBS-induced pulmonary vascular hyporesponsiveness to NA. In contrast, the addition, prior to the challenge with NA, of the NOS inhibitor NG-nitro-L-arginine methyl ester (L-NAME, 10(-4) M) or coincubation with dexamethasone (3 x 10(-6) M), a potent inhibitor of the induction of NOS, or with the protein synthesis inhibitor cycloheximide (10(-5) M) completely restored the reactivity to NA in LPS- and GBS-treated pulmonary arteries. 5. The incubation for 20 h of lung fragments with LPS and GBS produced a significant increase in the Ca2+-independent (inducible) NOS activity determined by the conversion of radiolabelled L-arginine to citrulline, but did not modify the constitutive NOS activity. This NOS induction was abolished by coincubation with dexamethasone (3 X 10-6 M).6. These results demonstrated that prolonged incubation with GBS and LPS causes an induction of NOS activity which results in a reduced vascular responsiveness to NA in pulmonary arteries of neonatal piglets. Thus, induction of NOS seems to be responsible for the delayed pulmonary vascular hyporesponsiveness induced by GBS (a Gram-positive) and E. coli (a Gram-negative), the most common causal agents of neonatal sepsis.

[Care according to patient gender in emergency services: different or unequal?]

It has been recently published different studies that support the idea that the health services make variability according to the patient's gender. In this sense, the aim of this study is to find out if there are gender differences in diagnostic and therapeutic care in health problems attended in emergency services. With the purpose of assessing this problem in a public hospital in Spain we have make a secondary analysis of the patient's findings got in the Emergency Service of Elche Hospital during four weeks in 1985.3, 709 patients were attended during this period. The results show a greater utilization of this service by men ORmale/female = 1.37 (1.29-1.47). The waiting time was higher for women (35 minutes) than men (29 minutes) (p = 0.0001), and also the time of getting a diagnostic (86 minutes vs 76) (p = 0.003). Diagnostic test were more frequent perform to women than men ORmale/female = 0.75 (0.64-0.85) meanwhile men receive treatment more often, ORmale/female = 1.34 (1.09-1.47). The associations are adjusted for age, diagnostic groups and patient's destination. Taking into account the possibility of more severity diseases among men that could explain the shorter waiting time and the therapeutic effort, the results show the possibility of an inequality attitude in the emergency services that would need further investigations. The more frequent use of diagnostic tests among women and consequently the longer diagnostic time, could be explain by the fact of the higher rates of nonspecific pathology.

Characterization of the invertase from Pichia anomala

Synthesis of invertase (EC 3.2.1.26) in Pichia anomala is controlled by the carbon source in the culture medium. The enzyme was purified to homogeneity from P. anomala cells fully derepressed for invertase synthesis and shown to be a multimeric glycoprotein composed of identical subunits with an apparent molecular mass of 86.5 kDa. The carbohydrate moiety accounts for approx. 30% of the total mass of the molecule and consists of manno-oligosaccharides N-linked to the polypeptide. Most of the characteristics of the enzyme analysed in this study were similar to those previously reported for other yeast invertases, with the remarkable exception of its thermal sensitivity which appears after 15 min incubation at temperatures above 32 degrees C.