Characterization of feather-degrading bacteria from Brazilian soils

Studies on keratinolytic microorganisms have been mainly related to their biotechnological applications and association with animal pathologies. However, these organisms have an ecological relevance to recycling keratinous residues in nature. This work aimed to select and identify new culturable feather-degrading bacteria isolated from soils of Brazilian Amazon forest and Atlantic forest. Bacteria that were isolated from temperate soils and bacteria from Amazonian basin soil were tested for their capability to grow on feather meal agar (FMA). Proteolytic bacteria were tested for feather degradation and were further identified according to their morphological and biochemical characteristics. Also, molecular identification based on 165 rDNA gene sequencing was carried out. A total of 24 proteolytic and 20 feather-degrading isolates were selected; Most of the isolates were from the Bacillus genus (division Firmicutes), but one Aeromonas, two Serratia (gamma-Proteobacteria), and one Chryseobacterium (Cytophaga-Flavobacterium group). (C) 2010 Elsevier Ltd. All rights reserved.

Morphological analysis of pitting corrosion in AISI 310S austenitic stainless steel after salt spray exposition

This paper aims to study evolution of increase, distribution and classification of pits in 310S austenitic stainless steels obtained in the state as-received and heat-treated under different exposure times in saline. This work applicability has been based on a technique development for morphologic characterization of localized corrosion associated with description aspects of shapes, size and population-specific parameters. Methodology has been consisted in the following steps: specimens preparation, corrosion tests via salt spray in different conditions, microstructural analysis, pits profiles analysis and images analysis, digital processing and image analysis in order to characterize the pits distribution, morphology and size. Results obtained in digital processing and profiles image analysis have been subjected to statistical analysis using median as parameter in the alloy as received and treated. The alloy as received displays the following morphology: hemispheric pits> transition region A> transition region B> irregular> conic. The pits amount in the treated alloy at each exposure time is: transition region B> hemispherical> transition region A> conic> irregular.

Molecular characterization of a miraculin-like gene differentially expressed during coffee development and coffee leaf miner infestation

The characterization of a coffee gene encoding a protein similar to miraculin-like proteins, which are members of the plant Kunitz serine trypsin inhibitor (STI) family of proteinase inhibitors (PIs), is described. PIs are important proteins in plant defence against insects and in the regulation of proteolysis during plant development. This gene has high identity with the Richadella dulcifica taste-modifying protein miraculin and with the tomato protein LeMir; and was named as CoMir (Coffea miraculin). Structural protein modelling indicated that CoMir had structural similarities with the Kunitz STI proteins, but suggested specific folding structures. CoMir was up-regulated after coffee leaf miner (Leucoptera coffella) oviposition in resistant plants of a progeny derived from crosses between C. racemosa (resistant) and C. arabica (susceptible). Interestingly, this gene was down-regulated during coffee leaf miner herbivory in susceptible plants. CoMir expression was up-regulated after abscisic acid application and wounding stress and was prominent during the early stages of flower and fruit development. In situ hybridization revealed that CoMir transcripts accumulated in the anther tissues that display programmed cell death (tapetum, endothecium and stomium) and in the metaxylem vessels of the petals, stigma and leaves. In addition, the recombinant protein CoMir shows inhibitory activity against trypsin. According to the present results CoMir may act in proteolytic regulation during coffee development and in the defence against L. coffeella. The similarity of CoMir with other Kunitz STI proteins and the role of CoMir in plant development and plant stress are discussed.

Carbide lime and industrial hydrated lime characterization

This paper focuses on the characterization of carbide lime (CL) - a by-product of acetylene production, composed mainly of calcium hydroxide with minor parts of carbonate - and compares its features to those of ""dry"" hydrated lime (HL) commonly used as a building material. Chemical, thermogravimetric and X-ray diffraction analyses indicated that the limes are similar in chemical and mineralogical compositions. except for the presence of carbon in the waste. Morphological and elemental chemical analyses by SEM and EDS revealed that CL particles differ from HL ones in their morphology and by the presence of carbon formations, Physical characterization included density and BET surface area of the materials. as well as, their particle size distributions in deionized water at diverse time periods. CL underwent agglomeration after approximately 60 min in water, whereas HL progressively became finer with time as determined by laser diffraction. In addition, water retention and squeeze flow tests were used to assess the pastes` fresh properties. (c) 2009 Elsevier B.V. All rights reserved.

Isolation and characterization of actinobacteria ectosymbionts from Acromyrmex subterraneus brunneus (Hymenoptera, Formicidae)

The ectosymbiont actinobacterium Pseudonocardia was isolated from the integument of Acromyrmex leaf-cutter ants and seems to play a crucial role in maintaining asepsis of the nest. Currently, there has been an intensive search for Pseudonocardia associated with several attine species, but few studies have indicated that other actinobacteria may be associated with these ants as well. We therefore characterized the culturable actinobacteria community associated with the integument of the fungus-growing ant Acromyrmex subterraneus brunneus Forel, 1893 (Hymenoptera: Formicidae). Ectosymbionts were isolated using four different media and characterized by morphological and molecular (16S rDNA) methods. A total of 20 strains were isolated, of which 17 were characterized as Streptomyces spp., and one isolate each as Pseudonocardia, Kitassatospora and Propionicimonas. Unlike other Acromyrmex species, A. subterraneus brunneus is associated with a diversity of actinobacteria. Even though Pseudonocardia is present on this leaf-cutting ant`s integument, the number and diversity of Streptomyces spp. found differs from those of previous studies with other attine ants and suggest that different culturing approaches are needed to characterize the true diversity of microbes colonizing the integument of attine ants. Moreover, understanding the diversity of the culturable actinobacteria associated with A. subterraneus brunneus should increase our knowledge of the evolutionary relationship of this intricate symbiotic association. (C) 2010 Elsevier GmbH. All rights reserved.

Molecular and morphological diversity in Japanese rice germplasm

Germplasm molecular and phenotypic characterization is instrumental to its utilization and to genetic variability incorporation into rice breeding programmes. The diversity within 192 Japanese rice accessions was analysed for 22 agro-morphological traits and 24 single sequence repeat markers. A total of 181 alleles were detected, 38 of which were exclusive. The number of alleles/marker ranged from 2 to 16, with an average of 7.54 alleles/locus and the H(e) value ranged from 0.01 to 0.82, with an average of 0.46. The accessions showed diversity at molecular and phenotypic level and few showed also good agronomic performance. Tocher`s method applied on a total-dissimilarity matrix was used to determine cluster formation of 13 diversity groups. Most of the accessions (81%) were clustered within a group, whereas eight accessions (Kyuushuu, Eika Ine, Ishiwari Mochi, Col/Fukui/1965, Ookuma Nishiki, Suzume Shirazu, Iwate Ryoon and Toga) did not cluster with other accessions.

Cloning and characterization of transcripts differentially expressed in the pulp of ripening papaya

Papaya (Carica papaya) is a relevant tropical crop and physico-chemical changes take place very quickly, as a consequence of activation of biochemical pathways by de nova synthesis of several proteins. Thus, in order to have information on the changes in gene expression in ripening papaya, transcripts from the pulp of unripe and ripe fruit were profiled by differential-display RT-PCR (DDRT-PCR). Seventy transcript derived fragments (TDFs) isolated from gels were re-amplified by PCR and differential expression of 40 papaya genes was confirmed by reverse northern blotting. Twenty-nine positively cloned TDFs were sequenced, and 17 were putatively identified by homology search. Ten of these genes were downregulated during ripening and UDP-glucose glucosyltransferase, alpha-2 importin, RNase L inhibitor-like protein, and a syntaxin protein were identified. Among the up-regulated genes there was a carboxylesterase, an integral membrane Yip1 family protein, a glycosyl hydrolase family-like protein and an endopolygalacturonase. Considering their relatedness to papaya quality, the fragments of genes potentially implicated in carbohydrate metabolism and pulp softening may be considered of interest for further studies. According to the results, differential display was a feasible approach to investigate differences in gene expression during fruit ripening, and can provide interesting information about those fruits whose genomic data is scarce, as is the case of papayas. (c) 2009 Elsevier B.V. All rights reserved.

Preparation and characterization of D, L-PLA loaded 17-beta-Estradiol valerate by emulsion/evaporation methods

PLA microparticles containing 17-beta-estradiol valerate were prepared by an emulsion/evaporation method in order to sustain drug release. This system was characterized concerning particle size, particle morphology and the influence of formulation and processing parameters on drug encapsulation and in vitro drug release. The biodegradation of the microparticles was observed by tissue histological analysis. Scanning electron microscopy and particle size analysis showed that the microparticles were spherical, presenting non-aggregated homogeneous surface and had diameters in the range of 718-880 nm (inert microparticles) and 3-4 mu m (drug loaded microparticles). The encapsulation efficiency was similar to 80%. Hormone released from microparticles was sustained. An in vivo degradation experiment confirmed that microparticles are biodegradable. The preparation method was shown to be suitable, since the morphological characteristics and efficiency yield were satisfactory. Thus, the method of developed microparticles seems to be a promising system for sustained release of 17-beta-estradiol.

Functional characterization of the Aspergillus fumigatus CRZ1 homologue, CrzA

The protein phosphatase calcineurin is an important mediator connecting calcium-dependent signalling to various cellular responses in multiple organisms. In fungi calcineurin acts largely through regulating Crz1p-like transcription factors. Here we characterize an Aspergillus fumigatus CRZ1 homologue, CrzA and demonstrate its mediation of cellular tolerance to increased concentrations of calcium and manganese. In addition to acute sensitivitiy to these ions, and decreased conidiation, the crzA null mutant suffers altered expression of calcium transporter mRNAs under high concentrations of calcium, and loss of virulence when compared with the corresponding complemented and wild-type strains. We use multiple expression analyses to probe the transcriptional basis of A. fumigatus calcium tolerance identifying several genes having calA and/or crzA dependent mRNA accumulation patterns. We also demonstrate that contrary to previous findings, the gene encoding the Aspergillus nidulans calcineurin subunit homologue, cnaA, is not essential and that the cnaA deletion mutant shares the morphological phenotypes observed in the corresponding A. fumigatus mutant, Delta calA. Exploiting the A. nidulans model system, we have linked calcineurin activity with asexual developmental induction, finding that CrzA supports appropriate developmental induction in a calcineurin and brlA-dependent manner in both species.

Partial characterization of proteins from baru (Dipteryx alata Vog) seeds

BACKGROUND: Baru (Dipteryx alata Vog.) is a fruit distributed throughout the Brazilian savanna and contains a seed with a high protein content, whose properties have been rarely explored. The purpose of this study was to characterize this protein, especially by isolation and quantifying its fractions and measuring some of its molecular properties. RESULTS: Baru seeds contain 244 g kg(-1) protein on a dry weight basis. Solubility profiles showed a preponderance of globulins. This fraction dominated the seed composition, with 61.7 wt% of the total soluble proteins. Albumins and glutelins accounted for 14 and 3.3 wt%, respectively. SDS-PAGE resolution of albumin and globulin showed main bands with molecular weights of 84 kDa and 64,66 and 73 kDa, respectively. The total protein of the flour and the globulin showed values of in vitro digestibility of 85.59% and 90.54%, relative to casein. Total globulin produced only one chromatographic peak, both on Sepharose CL-6B gel filtration and on DEAE-cellulose ion-exchange columns, eluted at a concentration of 0.12 mol L(-1) NaCl. CONCLUSION: The baru seed had high protein content with large quantities of storage proteins. The chromatographic and solubility profiles indicate the predominance of a fraction with characteristics of a legumin-type protein. (C) 2011 Society of Chemical Industry

Functional and structural characterization of isolated perfused stingray liver including effects of ischaemia/reperfusion

The morphological and functional characteristics of stingray liver were studied, including the effect of ischaemia/reperfusion. With an isolated perfused model, it was shown that the stingray liver was more resistant than the rat liver to ischaemia/reperfusion injury; this was consistent with the differing partial oxygen tensions usually present in the two species. This study confirmed that whereas stingray hepatocytes form tubules with central bile canaliculi as in other fish, the stingray liver has portal triads and a lobular architecture as in mammals. Apoptosis of hepatocytes, demonstrated in the normal liver, was only marginally enhanced by ischaemia/reperfusion. Resulting apoptotic bodies were phagocytized by macrophage-like cells in hepatocyte tubules. In contrast to rat liver, the stingray liver showed no necrosis after ischaemia-reperfusion. (C) 1998 W.B. Saunders Company Limited.

Molecular characterization of the toxic cyanobacterium Cylindrospermopsis raciborskii and design of a species-specific PCR

Cylindrospermopsis raciborskii is a toxic-bloom-forming cyanobacterium that is commonly found in tropical to subtropical climatic regions worldwide, but it is also recognized as a common component of cyanobacterial communities in temperate climates. Genetic profiles of C. raciborskii were examined in 19 cultured isolates originating from geographically diverse regions of Australia and represented by two distinct morphotypes. A 609-bp region of rpoC1, a DNA-dependent RNA polymerase gene, was amplified by PCR from these isolates with cyanobacterium-specific primers. Sequence analysis revealed that all isolates belonged to the same species, including morphotypes with straight or coiled trichomes. Additional rpoC1 gene sequences obtained for a range of cyanobacteria highlighted clustering of C. raciborskii with other heterocyst-producing cyanobacteria (orders Nostocales and Stigonematales). In contrast, randomly amplified polymorphic DNA and short tandemly repeated repetitive sequence profiles revealed a greater level of genetic heterogeneity among C. raciborskii isolates than did rpoC1 gene analysis, and unique band profiles were also found among each of the cyanobacterial genera examined. A PCR test targeting a region of the rpoC1 gene unique to C. raciborskii was developed for the specific identification of C. raciborskii from both purified genomic DNA and environmental samples. The PCR was evaluated with a number of cyanobacterial isolates, but a PCR-positive result was only achieved with C, raciborskii. This method provides an accurate alternative to traditional morphological identification of C. raciborskii.

The use of liquid phase adsorption isotherms for characterization of activated carbons

The characterization of three commercial activated carbons was carried out using the adsorption of various compounds in the aqueous phase. For this purpose the generalized adsorption isotherm was employed, and a modification of the Dubinin-Radushkevich pore filling model, incorporating repulsive contributions to the pore potential as well as bulk liquid phase nonideality, was used as the local isotherm. Eight different flavor compounds were used as adsorbates, and the isotherms were jointly fitted to yield a common pore size distribution for each carbon. The bulk liquid phase nonideality was incorporated through the UNIFAC activity coefficient model, and the repulsive contribution to the pore potential was incorporated through the Steele 10-4-3 potential model. The mean micropore network coordination number for each carbon was also determined from the fitted saturation capacity based on percolation theory. Good agreement between the model and the experimental data was observed. In addition, excellent agreement between the bimodal gamma pore size distribution and density functional theory-cum-regularization-based pore size distribution obtained by argon adsorption was also observed, supporting the validity of the model. The results show that liquid phase adsorption, using adsorptive molecules of different sizes, can be an effective means of characterizing the pore size distribution as well as connectivity. Alternately, if the carbon pore size distribution is independently known, the method can be used to measure critical molecular sizes. (C) 2001 Elsevier Science.

Preparation and characterization of Nickel-and cobalt-doped magnetites

Trabalho apresentado no I Simpósio Mineiro de Ciências dos Materiais, Ouro Preto, Novembro de 2001.