Subset of hybrid eukaryotic proteins is exported by the type I secretion system of Erwinia chrysanthemi

Erwinia chrysanthemi exports degradative enzymes by using a type I protein secretion system. The proteases secreted by this system lack an N-terminal signal peptide but contain a C-terminal secretion signal. To explore the substrate specificity of this system, we have expressed the E. chrysanthemi transporter system (prtDEF genes) in Escherichia coli and tested the ability of this ABC transporter to export hybrid proteins carrying C-terminal fragments of E. chrysanthemi protease B. The C terminus contains six glycine-rich repeated motifs, followed by two repeats of the sequences DFLV and DIIV. Two types of hybrid proteins were assayed for transport, proteins with the 93-residue-protease-B C terminus containing one glycine-rich repeat and both hydrophobic terminal repeats and proteins with the 181-residue C terminus containing all repeat motifs. Although the shorter C terminus is unable to export the hybrids, the longer C terminus can promote the secretion of hybrid proteins with N termini as large as 424 amino acids, showing that the glycine-rich motifs are required for the efficient secretion of these hybrids. However, the secretion of hybrids occurs only if these proteins do not carry disulfide bonds in their mature structures. These latter results suggest that disulfide bond formation can occur prior to or during the secretion. Disulfide bonds may prevent type I secretion of hybrids. One simple hypothesis to explain these results is that the type I channel is too narrow to permit the export of proteins with secondary structures stabilized by disulfide bonds.     

Dermatomycoses Caused by Nattrassia Mangiferae in São Paulo,Brazil

Nattrassia mangiferae formerly known as Hendersonula toruloidea,is a phaeoid coelomycete described by Nattrass in 1933. We report five casesof N. mangiferae infections in São Paulo, Brazil. This fungus wasisolated from interdigital lesions on the feet in one patient, toenails in threecases and fingernails in the other one. The infections were initially consideredto be caused by a dermatophyte. Although there are only a few cases describedin the medical literature, the five cases reported suggest that N. mangiferaeshould be taken into consideration in the differential diagnosis of tinea pedisinfections.     

A new case of rhinosporidiosis in Chile

BackgroundRhinosporidiosis is a chronic, granulomatous, and non-contagious infection, in which highly vascularized polyps (mainly present in the nasal cavity) appear. These polyps usually bleed easily.AimsTo present the case of a 14 year-old male suffering from an obstruction and injury of the right nostril due to a polypoid shaped-lesion with a raspberry-like appearance.MethodsA wide surgery resection of the base of the lesion was performed, as well as a standard histopathology procedure, including microscopic analysis with haematoxylin-eosin and Grocott staining.Results and conclusionsThe histopathology report indicated that the chronic inflammatory polyp was compatible with rhinosporidiosis.     

Mathematical modelling and simulation of aqueous two-phase continuous protein extraction.

A mathematical model has been developed to describe the continuous, steady-state operation of an aqueous two-phase system for protein extraction. The model is based on steady-state mass balances of the main components and phase equilibrium data. Experimental data on the separation of thaumatin from contaminant proteins of an homogenate of E. coli in a PEG4000/Phosphate system was used. The data shows the effect of the presence and absence of NaCl which was used to carry out the extraction of thaumatin into the PEG phase and back into the PO4(-3) phase. Simulation results showing the sensitivity to key process parameters, and the effect of process variables on performance are presented and discussed. The model can be used to predict performance and thus 'robustness' of process conditions as well as predict protein recovery yield and purity. This model can also be used to implement a suitable control strategy to maintain process stability.     

A new species of Podospora from soil in Chile

Podospora selenospora sp. nov. isolated from soil in Chile is described and illustrated. It belongs to the group of Podospora species with cylindrical asci, and inequilateral or curved ascospores, with a small, quickly evanescent primary appendage and absence of secondary appendages.     

Onychomycosis Caused by Fusarium Solani and Fusarium Oxysporum In São Paulo,Brazil

Fusarium species are common soil saprophytes and plant pathogens that have been frequently reported as etiologic agents of opportunistic infections in humans. We report eight cases of onychomycosis caused by Fusarium solani (4) and Fusarium oxysporum (4) in São Paulo, Brazil. These species were isolated from toenails in all cases. The infections were initially considered to be caused by dermatophytes. The clinical appearance of the affected toenails was leukonychia or distal subungual hyperkeratosis with yellowish brown coloration. The eight cases reported here suggest that Fusarium spp. should be taken into consideration in the differential diagnosis of tinea unguium.     

Eichhornia crassipes-based tertiary treatment of Kraft pulp mill effluents in Chilean Central Region

This paper presents experimental results on the implementation of Eichhornia crassipes–based tertiary lagoon to treat effluents generated by a 300 ton d^–1 Kraft pulp mill in Chile. Results show that E. crassipes rapidly adapted to the tertiary lagoon conditions. Active growth was maintained even during a cold winter, protected by the wastewater heat content. A 1000 m² seeding area extended to 2300–6200 m² after a month of growth, with a monthly harvested biomass and nitrogen uptake were 1.1–5.4 ton (dry wt.), and 18–127 kg N, respectively. E. crassipes growth was adequately described by a first order model, with an estimated rate constant ca. 0.03 d^–1 and 0.06 d^–1, for winter and summer seasons, respectively. A management strategy based on such model, to account for seasonal variations in growth rate while keeping a constant nitrogen uptake capacity, is proposed here.     

Abdominal zygomycosis in a bitch due to Absidia corymbifera

We report a case of abdominal zygomicosis in a Doberman bitch. Clinical signs consisted of urinary incontinence and hard abdominal masses detected by palpation. The masses were surgically removed by exploratory laparatomy and had a tumoral-like appearance. A granulomatous reaction containing coarse and non septate hyphae was the main histological finding. Direct microscopic examination revealed the presence of fungal structures. On Sabouraud honey agar the fungus developed fluffy, greyish white colonies that were identified as Absidia corymbifera on the basis of their macro and microscopic morphology.     

Differential bacterial growth kinetic and nitrification of fisheries wastewaters containing high ammonium and organic matter concentration by using pure oxygen

Nitrification with pure O of fisheries wastewaters high in N-NH4+ (0.2-1g/l) and in organic matter (1-2gCOD/l) gave specific growth rates for the bacteria degrading organic matter of 0.24h and for nitrifying bacteria of 0.15h. Average organic matter abatement was 75% whereas N-NH (0.7g/l as initial concentration) oxidation to nitrite and nitrate was 20%.