Applicability of papain solutions in immunohematology / Aplicabilidade de soluções de papaína em imuno-hematologia

ABSTRACT Objective: To compare the enzyme activity of different presentations of papain solution to validate in-house preparations. Methods: Two papain solutions were prepared, and the third presentation was a commercial solution. Tests were carried out with samples of red cells typed as weak RhD. Results: In-house prepared papain solutions showed similar enzyme reactivity, and statistically no differences compared to the enzyme activity of the commercial solution. Conclusion: Evaluating the cost-benefit ratio, the in-house prepared papain solutions present more economic advantages, and can be incorporated into immunohematological routines as a way to cope with periods of financial crisis and cost-containment policies.

RESUMO Objetivo: Comparar a atividade enzimática de diferentes apresentações de solução de papaína para validação de preparados in-house. Métodos: Foram preparadas duas soluções de papaína, e a terceira apresentação tratou-se de uma solução comercial. Os testes comparativos das reações enzimáticas foram realizados com amostras de hemácias tipadas como RhD fraco. Resultados: As soluções de papaína preparadas in-house apresentaram reatividade enzimática semelhante e estatisticamente sem diferenças em comparação com a atividade enzimática da solução comercial. Conclusão: Avaliando-se a relação entre custo e benefício, as soluções de papaína preparadas in-house são economicamente vantajosas, podendo ser incorporadas às rotinas imuno-hematológicas como forma de enfrentamento em períodos de crise financeira e em políticas de retenção de gastos.

Spoilage potential of psychrotrophic bacteria isolated from raw milk and the thermo-stability of their enzymes / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

The storage and transportation of raw milk at low temperatures promote the growth of psychrotrophic bacteria and the production of thermo-stable enzymes, which pose great threats to the quality and shelf-life of dairy products. Though many studies have been carried out on the spoilage potential of psychrotrophic bacteria and the thermo-stabilities of the enzymes they produce, further detailed studies are needed to devise an effective strategy to avoid dairy spoilage. The purpose of this study was to explore the spoilage potential of psychrotrophic bacteria from Chinese raw milk samples at both room temperature (28 °C) and refrigerated temperature (7 °C). Species of Yersinia, Pseudomonas, Serratia, and Chryseobacterium showed high proteolytic activity. The highest proteolytic activity was shown by Yersinia intermedia followed by Pseudomonas fluorescens (d). Lipolytic activity was high in isolates of Acinetobacter, and the highest in Acinetobacter guillouiae. Certain isolates showed positive β-galactosidase and phospholipase activity. Strains belonging to the same species sometimes showed markedly different phenotypic characteristics. Proteases and lipases produced by psychrotrophic bacteria retained activity after heat treatment at 70, 80, or 90 °C, and proteases appeared to be more heat-stable than lipases. For these reasons, thermo-stable spoilage enzymes produced by a high number of psychrotrophic bacterial isolates from raw milk are of major concern to the dairy industry. The results of this study provide valuable data about the spoilage potential of bacterial strains in raw milk and the thermal resistance of the enzymes they produce.

Enhanced production and organic solvent stability of a protease fromBrevibacillus laterosporus strain PAP04

A bacterial strain (PAP04) isolated from cattle farm soil was shown to produce an extracellular, solvent-stable protease. Sequence analysis using 16S rRNA showed that this strain was highly homologous (99%) to Brevibacillus laterosporus. Growth conditions that optimize protease production in this strain were determined as maltose (carbon source), skim milk (nitrogen source), pH 7.0, 40°C temperature, and 48 h incubation. Overall, conditions were optimized to yield a 5.91-fold higher production of protease compared to standard conditions. Furthermore, the stability of the enzyme in organic solvents was assessed by incubation for 2 weeks in solutions containing 50% concentration of various organic solvents. The enzyme retained activity in all tested solvents except ethanol; however, the protease activity was stimulated in benzene (74%) followed by acetone (63%) and chloroform (54.8%). In addition, the plate assay and zymography results also confirmed the stability of the PAP04 protease in various organic solvents. The organic solvent stability of this protease at high (50%) concentrations of solvents makes it an alternative catalyst for peptide synthesis in non-aqueous media.

Milk-deteriorating exoenzymes from Pseudomonas fluorescens 041 isolated from refrigerated raw milk

The practice of refrigerating raw milk at the farm has provided a selective advantage for psychrotrophic bacteria that produce heat-stable proteases and lipases causing severe quality problems to the dairy industry. In this work, a protease (AprX) and a lipase (LipM) produced by Pseudomonas fluorescens 041, a highly proteolytic and lipolytic strain isolated from raw milk obtained from a Brazilian farm, have been purified and characterized. Both enzymes were purified as recombinant proteins from Escherichia coli. The AprX metalloprotease exhibited activity in a broad temperature range, including refrigeration, with a maximum activity at 37 °C. It was active in a pH range of 4.0 to 9.0. This protease had maximum activity with the substrates casein and gelatin in the presence of Ca+2. The LipM lipase had a maximum activity at 25 °C and a broad pH optimum ranging from 7.0 to 10. It exhibited the highest activity, in the presence of Ca+2, on substrates with long-chain fatty acid residues. These results confirm the spoilage potential of strain 041 in milk due to, at least in part, these two enzymes. The work highlights the importance of studies of this kind with strains isolated in Brazil, which has a recent history on the implementation of the cold chain at the dairy farm.

Partial purification and characterization of extracellular protease from a halophilic and thermotolerant strain Streptomyces pseudogrisiolus NRC-15.

An alkaline protease was purified from a halophilic and thermotolerant potent alkaline protease-producing strain Streptomyces pseudogrisiolus NRC-15 using ammonium sulphate precipitation and Sephadex G-100 column chromatography. The enzyme was purified to 77.24-folds with a yield of 91.8% and the specific activity was 112 U/mg of protein. The protease showed a single band on SDS-PAGE with its molecular mass at 20 kDa and exhibited a maximum relative activity of 100% using casein as a substrate and. The enzyme had an optimum pH of 9.5 and displayed optimum activity at 50°C. The enzyme activity was completely inhibited by the serine protease inhibitor PMSF, suggesting the presence of serine residue in the active site. The enzyme activity was increased by the metal ions Ca2+, Co2+, K+ and Mg2+. The enzyme significantly enhanced the removal of stains when used with wheel detergent, indicating the potential of the enzyme for using as a laundry detergent additive to improve the performance of heavy-duty laundry detergent.

Virulence potential of filamentous fungi isolated from poultry barns in Cascavel, Paraná, Brazil / Potencial de virulência de fungos filamentosos isolados de celeiros de aves em Cascavel, Paraná, Brasil

Opportunistic fungi are those that normally would not cause diseases in otherwise healthy people, but are able to cause problems under some circumstances, and for this they need to possess a certain virulence potential. The objective of this study was to identify samples of filamentous fungi isolated from poultry barns in Cascavel, Paraná, and also to evaluate their virulence potential by assessing proteinase production, hemolytic activity, urease production, and growth rate at 37 ºC. We have evaluated the following samples: Acremonium hyalinulum (1 sample), Aspergillus sp. (12), Beauveria bassiana (1), Curvularia brachyspora (1), Paecilomyces variotti (1), and Penicillium sp. (2). Out of the 18 samples analyzed, 44.4 percent showed proteolytic activity using albumin as the substrate versus 66.7 percent when using casein; 66.7 percent showed hemolytic activity, 83.3 percent were positive for urea, and 88.9 percent grew at a temperature of 37 ºC. The results demonstrated that the majority of the isolates expressed virulence factors. Therefore, these isolates have the potential to harm human hosts, such as those working at poultry barns, especially predisposed or susceptible individuals.

Fungos oportunistas são aqueles que normalmente não causariam doenças em pessoas saudáveis, mas eles são capazes de causar problemas sob certas circunstâncias e, para isso, eles necessitam possuir algum potencial de virulência. O objetivo deste trabalho foi identificar amostras de fungos filamentosos isolados de granjas de aves em Cascavel, Paraná, e também avaliar o seu potencial de virulência, verificando a produção de proteinase, atividade hemolítica, produção de urease e crescimento a 37 ºC. Foram avaliados Acremonium hyalinulum (01), Aspergillus sp (12), Beauveria bassiana (01), Curvularia brachyspora (01), Paecylomices variotti (01) e Penicillium sp (02). Das 18 amostras, 44,4 por cento apresentaram atividade proteolítica usando como substrato a albumina e 66,7 por cento com caseína; 66,7 por cento demonstraram atividade hemolítica, 83,3 por cento foram uréia positivas e 88,9 por cento cresceram em temperatura de 37 ºC. Os resultados demonstram que a maioria dos isolados expressaram fatores de virulência e, portanto, têm potencial para causar danos a hospedeiros humanos como os trabalhadores dos aviários, sobretudo em indivíduos predispostos ou suscetíveis.

The use of Fluorescence Resonance Energy Transfer (FRET) peptidesfor measurement of clinically important proteolytic enzymes

Proteolytic enzymes have a fundamental role in many biological processes and are associated with multiple pathological conditions. Therefore, targeting these enzymes may be important for a better understanding of their function and development of therapeutic inhibitors. Fluorescence Resonance Energy Transfer (FRET) peptides are convenient tools for the study of peptidases specificity as they allow monitoring of the reaction on a continuous basis, providing a rapid method for the determination of enzymatic activity. Hydrolysis of a peptide bond between the donor/acceptor pair generates fluorescence that permits the measurement of the activity of nanomolar concentrations of the enzyme. The assays can be performed directly in a cuvette of the fluorimeter or adapted for determinations in a 96-well fluorescence plate reader. The synthesis of FRET peptides containing ortho-aminobenzoic acid (Abz) as fluorescent group and 2, 4-dinitrophenyl (Dnp) or N-(2, 4-dinitrophenyl)ethylenediamine (EDDnp) as quencher was optimized by our group and became an important line of research at the Department of Biophysics of the Federal University of São Paulo. Recently, Abz/Dnp FRET peptide libraries were developed allowing high-throughput screening of peptidases substrate specificity. This review presents the consolidation of our research activities undertaken between 1993 and 2008 on the synthesis of peptides and study of peptidases specificities.

As enzimas proteolíticas têm um papel fundamental em muitos processos biológicos e estão associadas a vários estados patológicos. Por isso, o estudo da especificidade das peptidases pode ser importante para uma melhor compreensão da função destas enzimas e para o desenvolvimento de inibidores. Os substratos com supressão intramolecular de fluorescência constituem uma excelente ferramenta, pois permitem o monitoramento da reação de forma contínua, proporcionando um método prático e rápido para a determinação da atividade enzimática. A hidrólise de qualquer ligação da cadeia peptídica entre o grupo doador e o grupo supressor gera fluorescência que permite detectar concentração nanomolar de enzima. Os ensaios podem ser acompanhados diretamente na cubeta ou adaptados para determinações de fluorescência em leitoras de placa. A síntese dos peptídeos com supressão intramolecular de fluorescência contendo o grupo fluorescente Abz (orto-aminobenzóico) e o grupo supressor EDDnp (N-[2, 4-dinitrofenil]-etilenodiamino ou Dnp (2, 4-dinitrophenyl) foi otimizada pelo nosso grupo e tornou-se uma importante linha de pesquisa no Departamento de Biofísica da Universidade Federal de São Paulo. Recentemente, foram desenvolvidas bibliotecas de peptídeos fluorogênico contendo Abz/Dnp como grupo doador/supressor trazendo um grande avanço no estudo de especificidade das peptidases. Esta revisão apresenta o trabalho desenvolvido pelo nosso grupo entre 1993 e 2008 sobre a síntese de peptídeos e o estudo da especificidade de peptidases.

Processing of multimer FMD virus VP1-2A protein expressed in E. coli into monomers.

Expressions of several genes in bacteria were carried out by independent promoter. However, in case of eukaryotes ribosome skipping and introduction of IRES are employed as alternative to multiple translation initiation. Foot and mouth disease virus (FMDV) 2A peptide has been widely used for co-expression of multiple genes in eukaryotic, plant and mammalian systems. The 18 amino acid 2A peptide of FMDV facilitates efficient co-translational dissociation of the polyprotein into discrete protein products. To study the role of 2A in multimeric protein production a construct consisting of tandem repeat of 4 units of C- terminal VP1 linked through 2A sequence was made and expressed in E. coli. Along with tetramer protein, trimer, dimer and monomer proteins were produced. Stability studies showed that the tetramer protein was cleaved to smaller monomer on storage. The results provide scope for using FMDV 2A for expressing multiple genes under a single promoter in prokaryotes.

Identification of digestive hydrolases in the larval midgut of the camel nasal bot fly cephalopina titilla tor clark [diptera: Oestridae]

Activities of digestive hydrolases associated with midgut of the third instar larva of Cephalopina titillator were investigated. Based on the hydrolysis of synthetic substrates and optimum pH, it was found that C. titillator midgut contains trypsin-like [optimum pH, 9], chymotrypsin esterase-like [optimum pH, 8], carboxypeptidase A and B [optimum pH at 8.5 and 7 respectively], alkaline- and acidphosphatase [optimum pH at 9 and 5 respectively] and membrane bound leucine aminopeptidase [optimum pH, 8]. An acid proteinase activity was detected, by the ability to hydrolyze acid denaturated haemoglobin; and it seems to be close to pepsin than cathepsin-like enzyme. It has a maximum activity at pH 3.5. alpha-Glucosidase activity, and was also identified [optimum pH at 6] in the midgut, and seems to be membrane bound

Identification of 38kDa Brugia malayi microfilarial protease as a vaccine candidate for lymphatic filariasis.

A FPLC purified 38kDa protease (Bm mf S-7) isolated from B. malayi microfilarial soluble antigen was identified. It showed pronounced reactivity with sera collected from 'putatively immune' asymptomatic and amicrofilaraemic individuals residing in an endemic area for bancroftian filariasis. Further the immune protective activity of Bm mf S-7 antigen was evaluated in susceptible hosts, jirds (Meriones unguiculatus) against B. malayi filarial infection. The antigen showed 89% cytotoxicity against mf and 87-89% against infective (L3) larvae in in vitro antibody dependent cellular cytotoxicity Assay (ADCC) and in situ micropore chamber methods. Bm mf S-7 immunized jirds after challenge infection showed 81.5% reduction in the adult worm burden. The present study has shown that, the 38kDa microfilarial proteases (Bm mf S-7) could stimulate a strong protective immune response against microfilariae and infective larvae in jird model to block the transmission of filariasis. Analysis of IgG subclasses against Bm mf S-7 revealed a significant increase in IgG2 and IgG3 antibodies in endemic normals. Lymphocyte proliferation to Bm mf S-7 was significantly high in endemic normal group as compared to that in clinical and microfilarial carriers. Significantly enhanced levels of IFN-gamma in the culture supernatant of PBMC of endemic normals followed by stimulation with Bm mf S-7 suggest that the cellular response in this group is skewed towards Th 1 type.

Production of an extracellular keratinase from Chryseobacterium sp. growing on raw feathers

The strain Chryseobacterium sp. kr6 shown to be useful for biotechnological purposes such as hydrolysis of poultry feathers and de-hairing of bovine pelts. The effect of temperature, initial pH and media composition on protease production by this keratinolytic strain was studied. The enzyme was produced between 25 and 37ºC, with maximum activity and yield at 30ºC. When protease production was tested in media with different initial pH, maximum activity was observed when cultivation was carried out at 30ºC and initial pH ranging from 6.0 to 8.0. Higher activity was observed when feathers or feather meal were used as growth substrates, followed by soybean meal. The addition of carbohydrates or surfactants to feather broth resulted in decrease in keratinolytic activity.

Evaluation of protein and peptide hydrolases in DOCA-salt hypertensive rats treated with chlorthalidone

We have reported that chlorthalidone (Chlor) prevents the development of heart hypertrophy in deoxycorticosterone acetate (DOCA)-salt hypertensive rats. The present study was carried out to determine whether Chlor (8 mg/day per animal, added to the food, for 20 days) affects kidney and heart hypertrophy in DOCA-salt (8 mg/kg, sc, twice a week) rats by causing alterations in protein and peptide hydrolysis Heart (left ventricle) and kidney enzyme activities were measured i tissue homogenates from normal-control, salt-control, DOCA-sa salt and DOCA-salt-Chlor male Wistar rats (N = 6 for each group), using azocasein as the substrate for proteolytic enzymes and specific peptides for prolylendopeptidase (PEP) and multicatalytic proteinase (MCP). The tissue weight/body weight ratio increased in parallel to elevation of blood pressure. The left ventricular muscle hypertrophy (26 per cent, P<0.05) present in the DOCA-salt hypertensive group was completely prevented by simultaneous Chlor treatment. Chlor treatment did not change the kidney hypertrophy (+79 per cent, P<0.05) observe in the salt-control (+57 per cent, P<0.05) and DOCA-salt (+74 per cent, P<0.05) groups. The hydrolysis of peptides by PEP and MCP was similar in the normal and salt-control groups. The heart PEP activity was 24 per cent higher (P<0.01) in DOCA-salt rats, whereas MCP activity was not different when compared to control groups. DOCA-salt treatment increased MCP activity in the kidney by 44 per cent while PEP activity did not differ from that of control groups. The hydrolysis of proteins by heart enzymes was increased by salt by 47 per cent. Chlor treatment restored the reduction in protein hydrolysis induced by DOCA-salt (a 21 per cent decrease, P<0.05) to a level similar to that of the normal-control group. Similarly, Chlor coadministration prevented the 30 per cent reduction in renal proteolytic activity elicited by DOCA-salt treatment. Although Chlor treatment prevented the DOCA-salt-induced reduction in protein hydrolysis, this response did not interfere with kidney hypertrophy. The mechanism by which hypertension produces hypertrophy is unclear, but our results suggest that this structural modification is not related to the activities of some peptidases, e.g. protein and peptide hydrolases.