RESUMO

The clinical course of breast cancer (BC) and survival depend on a wide range of risk factors. From the psychosomatic point of view, BC is one of the most studied type of cancer but there is no evidence available for this relation. Therefore, in the present study we evaluate the impact of chronic life stressors in BC patients. A total of 100 BC patients were invited to participate in an interview, when information about social parameters and emotional changes in the period prior to diagnosis were collected. The emotional changes were evaluated by the Holmes and Rahe's Stress Scale, which analyzes the difficulty required for a person to readjust to society after significant changes in their life. Clinicopathological parameters were obtained from the medical records. For all data, the level of significance adopted was p <0.05. It was observed that 55.2 % of the patients have a medium and 13.8 % were at high risk for disease development related to stressful events in the period prior to the BC diagnosis. The highest stress levels were presented by separated, divorced, or widowed patients compared to married (p <0.01) and single (p = 0.037) patients. The high-risk (HR) group had a lower proportion of positivity for estrogen receptor when compared to the low (LR) and moderate risk (MR) groups (p= 0.001). In addition, a binary logistic regression analysis was performed, and we found that the relationship between the estrogen receptor and the HR of chronic stress was independently associated with the histological type of BC and lymph nodes involvement. The relationship of stressful life experiences and BC is not well established, so our study collaborates with the literature to demonstrate the importance of stress as a factor associated with the development of BC.

RESUMO

Transforming growth factor beta 1 (TGFß1) is a pleiotropic cytokine that acts in a context-dependent manner. In breast cancer (BC) this cytokine exerts subtype- and stage-specific roles, inhibiting poorly aggressive tumors while enhances the invasive potential of highly aggressive cancers. Single-nucleotide polymorphisms (SNPs) affecting TGFß1 production largely reflect this pattern of association, but studies investigating systemic TGFß1 levels in BC patients and their association with clinical features or SNPs produced conflicting conclusions. Therefore, the present work investigated plasmatic TGFß1 levels through enzyme linked immunosorbent assay (ELISA) in 341 individuals previously genotyped for four TGFB1 SNPs [G-800A (rs1800468), C-509T (rs1800469), T29C (rs1800470) and G74C (rs1800471)], encompassing 184 neoplasia-free women with clinical information regarding health status, 113 treatment-free pre-surgery BC patients and 44 treated BC patients. Results have shown that TGFß1 levels varied greatly in function of health status in neoplasia-free women, and disease-free individuals had higher TGFß1 levels than both treatment-free or treated BC patients. There was no correlation between TGFß1 with clinicopathological features in treatment-free BC general group, but it was negatively correlated with tumor size in luminal-B-HER2+ patients and with histopathological grade in triple-negative group. Also, TGFB1 ACTG haplotype (from G-800A to G74C) was associated with decreased TGFß1 levels compared to the reference GCTG haplotype, and regression analyses showed that this association was independent of age, health status or BC diagnosis. In conclusion, several factors may influence TGFß1 levels, and ACTG haplotype seems to be an important factor regulating TGFß1 production.

RESUMO

PURPOSE: APOBEC3A and APOBEC3B cytidine deaminases have been implicated in the pathogenesis of multiple cancers, including breast cancer (BC). A germline deletion linking APOBEC3A and APOBEC3B loci (A3A/B) has been associated with higher APOBEC-mediated mutational burden, but its association with BC risk have been controversial. Therefore, this study investigated the association between A3A/B and BC susceptibility and clinical presentation in a Brazilian cohort. METHODS: A3A/B deletion was evaluated through allele-specific PCR in 341 BC patients and 397 women without familial or personal history of neoplasia from Brazil and associations with susceptibility to BC subtypes were tested through age-adjusted logistic models while correlations with clinicopathological parameters were tested using Kendall's tests. RESULTS: No association was found between A3A/B and BC susceptibility; however, in Luminal-A BCs, it was positively correlated with tumor size (Tau-c = 0.125) and Ki67 (Tau-c = 0.116) and negatively correlated with lymph node metastasis (LNM) (Tau-c = - 0.162). The negative association between A3A/B with LNM in Luminal-A BCs remained significant even after adjusting for tumor size and Ki67 in logistic models (OR = 0.22; p = 0.008). CONCLUSION: These results show that although A3A/B may not modify BC susceptibility in Brazilian population, it may affect clinicopathological features in BC subtypes, promoting tumor cell proliferation while being negatively associated with LNM in Luminal-A BCs.

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PURPOSE: Transforming growth factor beta (TGFß) has paradoxical effects in breast cancer (BC), inhibiting initial tumors while promoting aggressive ones. A polymorphism on TGFBR2 promoter region (G-875A, rs3087465) increases TGFß type II receptor expression and is protective against cancer. Previously, we have shown that TGFB1 variants have subtype-specific roles in BC. This work sought to investigate the association between TGFBR2 and susceptibility and clinicopathological features in BC subgroups. METHODS: TGFBR2 G-875A was analyzed through PCR-RFLP in 388 BC patients and 405 neoplasia-free women. Case-control analyses as well as interaction with TGFB1 haplotypes previously associated with BC were tested through age-adjusted logistic regression. Correlations between G-875A and clinicopathological parameters were assessed through Kendall's Tau-b test. All statistical tests were two-tailed (α = 0.05). RESULTS: TGFBR2 G-875A was protective against BC in additive, genotypic, and dominant models. In subgroup-stratified analyses, these effects were greater in hormonal receptor-positive and luminal-A tumors, but were not significant in other subgroups. Logistic models including TGFB1 variants showed that in luminal-A tumors, G-875A retained its significance while TGFB1 haplotype showed a trend towards significance; otherwise, in HER2+ tumors TGFB1 variants remained significant while TGFBR2 showed a trend for association. There was no interaction between these genes. In correlation analyses, G-875A positively correlated with histopathological grade in total sample, and a trend towards significance was observed in triple-negative BCs. CONCLUSION: These results indicate that G-875A is a protective factor against BC, especially from luminal-A subtype, but may promote anaplasia in established tumors, consistent with TGFß signaling roles in BC.

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PURPOSE: Despite the documented dual role of TGFß1 in breast cancer (BC) pathogenesis, the subtype-specific influences of its polymorphisms remain undocumented. The present study investigated the effects of the TGFB1 promoter region (rs1800468 or G-800A and rs1800469 or C-509T) and signal peptide (rs1800470 or C29T and rs1800471 or G74C) single nucleotide polymorphisms (SNPs) and their haplotype structures on the susceptibility and clinicopathological presentation of BC subtypes. METHODS: TGFB1 genotypes were assessed by PCR-RFLP and haplotype structures were inferred for 323 BC patients and 405 neoplasia-free women, and case-control analyses were performed by logistic regression adjusted by age. Clinicopathological parameters (age at diagnosis, tumor size, histopathological grade, lymph node metastasis, proliferation index and disease stage) were tested for correlation with TGFB1 variants. All statistical analyses were two-tailed with an alpha level of 0.05. RESULTS: Variants related to increased TGFß1 production (C-509T SNP and GTCG haplotype) were associated with increased susceptibility to HER2+ tumors and correlated with worse prognostic parameters in HER2+ and triple-negative (TN) BCs, but correlated negatively to Ki67 in ER/PR+HER2- tumors. Conversely, low TGFß1 production variants (C29T SNP and GCTG haplotype) were protective against HER2+ tumors and correlated negatively with prognostic parameters in HER2+ and TN BCs, while indicating higher proliferation rates in ER/PR+HER2- tumors. Furthermore, the GCCG haplotype was associated with decreased susceptibility to ER/PR+HER2- tumors, but correlated positively with Ki67 in this subgroup. CONCLUSION: The present study indicates that TGFB1 variants have subtype-specific roles in BC and may switch from tumor suppressor to promoter during tumor development, consistent with TGFß1 dual role in BC pathogenesis.

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Breast cancer (BC) is the main worldwide neoplasia in women. The metabolic balance between xenobiotic absorption and elimination rates plays an important role in preventing DNA damage and, consequently, tumor development. The glutathione S-transferases (GSTs), such as GSTM1 and GSTT1, and the NAD(P)H quinone oxidoreductase are important enzymes involved in phase II detoxification reactions. Deletions in GSTM1 and GSTT1, and single-nucleotide polymorphism (SNP) in NQO1 (rs1800655) have been investigated in cancer context, revealing conflicting results. The present study analyzed these genetic polymorphisms in 121 BC patients and 151 BC-free controls in order to verify if they could act as susceptibility modifiers and/or prognostic factors. Binary logistic regressions adjusted by age were performed to assess associations between allelic variants and interactions in polymorphisms combination with BC susceptibility, but no significant association was found. Genotypes distribution was also compared between BC subtypes, but no significant difference was observed (p > 0.05). GSTM1 deletion was significantly associated with histopathological grade, with a greater proportion of patients presenting grade III tumors (p = 0.007). Univariate analysis identified tumor size as the only clinicopathological parameter potentially associated with recurrence risk in patients that received adjuvant chemotherapy (p < 0.1). Thus, logistic regression analysis adjusted by tumor size revealed a positive association between GSTT1 deletion and recurrence risk in general BC (OR 4.25; p = 0.04), while GSTM1 was negatively associated with recurrence risk in ER/PR+HER2- samples (OR 0.07; p = 0.03). In conclusion, the present study indicated that GSTT1 deletion was associated with increased recurrence risk, while GSTM1 correlated with worst prognosis parameters at diagnosis, but was negatively associated with recurrence risk in luminal subtype samples.

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Many tumor cells express chemokines and chemokine receptors, and these molecules can affect both tumor progression and anti-tumor immune response. Genetic polymorphisms of some chemokine receptors were found to be closely related to malignant tumors, especially in metastasis process, including breast cancer (BC). Considering this, it was investigated a possible role for CCR2-V64I (C-C chemokine receptor 2) and CCR5-Δ32 (C-C chemokine receptor 5) genetic variants in BC context. Patients were divided into subgroups according to immunohistochemical profile of estrogen (ER) and progesterone (PR) receptors and the human epidermal growth factor receptor 2 (HER2) overexpression. No significant associations were found in relation to susceptibility (CCR2-V64I: OR 1.32; 95 % CI 0.57-3.06; CCR5-∆32: OR 1.04; 95 % CI 0.60-1.81), clinical outcome (tumor size, lymph nodes commitment and/or distant metastasis, TNM staging and nuclear grade) or therapeutic response (recurrence and survival). However, it was found a significant correlation between CCR2-V64I allelic variant and HER2 immunohistochemical positive samples (p = 0.026). All in all, we demonstrate, for the first time, a positive correlation between CCR2 receptor gene polymorphism and a subgroup of BC related to poor prognosis, which deserves further investigation in larger samples for validation.

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CXCR4 genetic polymorphisms, as well as their expression level, have been associated with cancer development and prognosis. The present study aimed to investigate the influence of CXCR4 rs2228014 polymorphism on its mRNA and protein expression in breast cancer samples. It was observed that patients presented higher CXCR4 mRNA relative expression (5.7-fold) than normal mammary gland, but this expression was not correlated with patients clinicopathological features (nuclear grade, nodal status, ER status, PR status, p53 staining, Ki67 index, and HER-2 status). Moreover, CXCR4 mRNA relative expression also did not differ regarding the presence or absence of T allele (p = 0.301). In the immunohistochemical assay, no difference was observed for CXCR4 cytoplasmic protein staining in relation to different genotypes (p = 0.757); however, high cytoplasmic CXCR4 staining was verified in invasive breast carcinoma (p < 0.01). All in all, the results from present study indicated that rs2228014 genetic variant does not alter CXCR4 mRNA or protein expression. However, this receptor was more expressed in tumor compared to normal tissue, in both RNA and protein levels, suggesting its promising applicability in the general context of mammary carcinogenesis.

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A subgroup of tumor that has received attention is triple-negative breast cancer (TNBC), which presents phenotype of negative estrogen receptor, negative progesterone receptor and has no overexpression of HER2. TP53 acts as a tumor suppressor limiting the proliferation of damaged cells. A polymorphic site (rs1042522) of TP53 encodes either an arginine or a proline amino acid, but its biological significance remains unclear. This study aimed to investigate this variant and its expression in search for a possible involvement in TNBC susceptibility and clinical outcome. Genetic polymorphism was evaluated in 50 patients and 115 controls by PCR based methodology and immunohistochemistry was done with monoclonal antibody. Case-control study showed no positive or negative association (OR= 0.95; CI95%= 0.48-1.89). Comparison of genotypes and clinical outcome showed no significant results. Despite most of patients presented p53 positive staining by immunohistochemistry, there was no significant association in relation to prognostic parameters. Results demonstrated a lack of association between codon 72 polymorphism, susceptibility and prognosis of TNBC. Immunohistochemistry analysis should be done more carefully, since most of the patients had the somatic mutation of p53, which could be an indicator of prognostic value in TNBC.

RESUMO

Triple negative breast cancer (TNBC) is a relevant subgroup of neoplasia which presents negative phenotype of estrogen and progesterone receptors and has no overexpression of the human epidermal growth factor 2 (HER2). FOXP3 (forkhead transcription factor 3) is a marker of regulatory T cells (Tregs), whose expression may be increased in tumor cells. This study aimed to investigate a polymorphism (rs3761548) and the protein expression of FOXP3 for a possible involvement in TNBC susceptibility and prognosis. Genetic polymorphism was evaluated in 50 patients and in 115 controls by allele-specific PCR (polymerase chain reaction). Protein expression was evaluated in 38 patients by immunohistochemistry. It was observed a positive association for homozygous AA (OR = 3.78; 95% CI = 1.02-14.06) in relation to TNBC susceptibility. Most of the patients (83%) showed a strong staining for FOXP3 protein in the tumor cells. In relation to FOXP3-positive infiltrate, 47% and 58% of patients had a moderate or intense intratumoral and peritumoral mononuclear infiltrate cells, respectively. Tumor size was positively correlated to intratumoral FOXP3-positive infiltrate (P = 0.026). In conclusion, since FOXP3 was positively associated with TNBC susceptibility and prognosis, it seems to be a promising candidate for further investigation in larger TNBC samples.

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Basidiomicetos têm sido amplamente utilizados como produtores de enzimas, no entanto são pouco explorados quanto a sua capacidade de produção de proteases. Estes fungos são reconhecidos pelas suas propriedades antitumorais, hipocolesterolêmicas, antimutagênicas, antioxidantes entre outras. Assim, a associação destas propriedades aos derivados do leite pode potencializar estes produtos como alimentos funcionais. Neste sentido, o objetivo deste trabalho foi selecionar basidiomicetos produtores de proteases, com potencial uso no processo de fabricação de derivados do leite. Foram utilizadas 27 linhagens de fungos crescidas em meio mínimo adicionado de 0,2% de caseína. A atividade proteolítica foi verificada pela formação de halo pela adição de uma solução saturada de (NH4)2SO4. Concluiu-se que a produção de proteases não apresenta relação com o crescimento micelial. O melhor produtor de proteases é a linhagem Lentinula edodes U8/1, seguida por Pleurotus sp (U2/9, U6/10 e U2/11). Os basidiomicetos Agaricus blazei (U4/3), Agaricus sp (U5/1), Flamulina sp (U5/4), Lycoperdon sp (U8/8), Agaricus blazei (U2/7), Agaricus blazei (U7/2), Agaricus blazei (U7/4) e Agaricus blazei (U7/5) não produzem proteases suficientes para serem medidas pela metodologia. Desta forma, estes resultados embasam o uso de Lentinula edodes e Pleurotus sp para o desenvolvimento de potenciais aplicações na hidrólise de proteínas em alimentos.

Basidiomycetes have been widely used as enzyme producers, but are poorly explored about their ability to produce protease. These fungi are known as antitumor, cholesterol-lowering, antimutagenic, antioxidant among other biological activities. Thus, the combination of basidiomycete properties to dairy products can improve them as functional foods. Therefore, the objective of this work was to screen basidiomycete protease producers to prospect the use of these fungi on dairy products. 27 basidiomycete strains grown on minimal medium supplemented with 0.2% casein were used. The proteolytic activity was verified by halo formation after a (NH4)2SO4 saturated solution addition on the culture medium. The production of proteases is not associated with mycelial growth. The best producers of proteases is Lentinula edodes U8/1 and after Pleurotus sp (U2/9, U6/10 e U2/11). The basidiomycetes of Agaricus blazei (U4/3), Agaricus sp (U5/1), Flamulina sp (U5/4), Lycoperdon sp (U8/8), Agaricus blazei (U2/7), Agaricus blazei (U7/2), Agaricus blazei (U7/4) and Agaricus blazei (U7/5) do not produce enough proteases to be measured by the methodology. Thus, these results support the use of Lentinula edodes and Pleurotus sp as potencial basidiomycetes for protein hydrolysis on food.

Basidiomicetos han sido ampliamente utilizados como productores de enzimas, pero poco exploradas en su capacidad de producción de proteasa. Estos hongos son reconocidos por sus propiedades antitumorales, reductor de colesterol, antimutagénicos, antioxidantes entre otras. Así, la asociación de estas propiedades a los derivados de la leche puede potencializar estos productos como alimentos funcionales. En este sentido, el objetivo de este trabajo fue seleccionar basidiomicetos productores de proteasas, con potencial uso en el proceso de fabricación de productos lácteos. Se utilizó 27 cepas de hongos crecidos en medio mínimo adicionado de 0,2% de caseína. La actividad proteolítica fue verificada por formación de halo por la adición de solución saturada de (NH4)2SO4. Se concluyó que la producción de proteasas no presenta relación con el crecimiento del micelio. El mejor productor de proteasas es la cepa de Lentinula edodes U8/1, seguida por Pleurotus sp (U2/9, U6/10 y U2/11). Los basidiomicetos Agaricus blazei (U4/3), Agaricus sp (U5/1), Flamulina sp (U5/4), Lycoperdon sp (U8/8), Agaricus blazei (U2/7), Agaricus blazei (U7/2), Agaricus blazei (U7/4) y Agaricus blazei (U7/5) no producen proteasas suficientes para que sean medidos por la metodología. Por lo tanto, estos resultados apoyan el uso de Lentinula edodes y Pleurotus sp para el desarrollo de potenciales aplicaciones en hidrólisis de proteínas en alimentos.

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RESUMO

Basidiomicetos têm sido amplamente utilizados como produtores de enzimas, no entanto são pouco explorados quanto a sua capacidade de produção de proteases. Estes fungos são reconhecidos pelas suas propriedades antitumorais, hipocolesterolêmicas, antimutagênicas, antioxidantes entre outras. Assim, a associação destas propriedades aos derivados do leite pode potencializar estes produtos como alimentos funcionais. Neste sentido, o objetivo deste trabalho foi selecionar basidiomicetos produtores de proteases, com potencial uso no processo de fabricação de derivados do leite. Foram utilizadas 27 linhagens de fungos crescidas em meio mínimo adicionado de 0,2% de caseína. A atividade proteolítica foi verificada pela formação de halo pela adição de uma solução saturada de (NH4)2SO4. Concluiu-se que a produção de proteases não apresenta relação com o crescimento micelial. O melhor produtor de proteases é a linhagem Lentinula edodes U8/1, seguida por Pleurotus sp (U2/9, U6/10 e U2/11). Os basidiomicetos Agaricus blazei (U4/3), Agaricus sp (U5/1), Flamulina sp (U5/4), Lycoperdon sp (U8/8), Agaricus blazei (U2/7), Agaricus blazei (U7/2), Agaricus blazei (U7/4) e Agaricus blazei (U7/5) não produzem proteases suficientes para serem medidas pela metodologia. Desta forma, estes resultados embasam o uso de Lentinula edodes e Pleurotus sp para o desenvolvimento de potenciais aplicações na hidrólise de proteínas em alimentos.(AU)

Basidiomycetes have been widely used as enzyme producers, but are poorly explored about their ability to produce protease. These fungi are known as antitumor, cholesterol-lowering, antimutagenic, antioxidant among other biological activities. Thus, the combination of basidiomycete properties to dairy products can improve them as functional foods. Therefore, the objective of this work was to screen basidiomycete protease producers to prospect the use of these fungi on dairy products. 27 basidiomycete strains grown on minimal medium supplemented with 0.2% casein were used. The proteolytic activity was verified by halo formation after a (NH4)2SO4 saturated solution addition on the culture medium. The production of proteases is not associated with mycelial growth. The best producers of proteases is Lentinula edodes U8/1 and after Pleurotus sp (U2/9, U6/10 e U2/11). The basidiomycetes of Agaricus blazei (U4/3), Agaricus sp (U5/1), Flamulina sp (U5/4), Lycoperdon sp (U8/8), Agaricus blazei (U2/7), Agaricus blazei (U7/2), Agaricus blazei (U7/4) and Agaricus blazei (U7/5) do not produce enough proteases to be measured by the methodology. Thus, these results support the use of Lentinula edodes and Pleurotus sp as potencial basidiomycetes for protein hydrolysis on food.(AU)

Basidiomicetos han sido ampliamente utilizados como productores de enzimas, pero poco exploradas en su capacidad de producción de proteasa. Estos hongos son reconocidos por sus propiedades antitumorales, reductor de colesterol, antimutagénicos, antioxidantes entre otras. Así, la asociación de estas propiedades a los derivados de la leche puede potencializar estos productos como alimentos funcionales. En este sentido, el objetivo de este trabajo fue seleccionar basidiomicetos productores de proteasas, con potencial uso en el proceso de fabricación de productos lácteos. Se utilizó 27 cepas de hongos crecidos en medio mínimo adicionado de 0,2% de caseína. La actividad proteolítica fue verificada por formación de halo por la adición de solución saturada de (NH4)2SO4. Se concluyó que la producción de proteasas no presenta relación con el crecimiento del micelio. El mejor productor de proteasas es la cepa de Lentinula edodes U8/1, seguida por Pleurotus sp (U2/9, U6/10 y U2/11). Los basidiomicetos Agaricus blazei (U4/3), Agaricus sp (U5/1), Flamulina sp (U5/4), Lycoperdon sp (U8/8), Agaricus blazei (U2/7), Agaricus blazei (U7/2), Agaricus blazei (U7/4) y Agaricus blazei (U7/5) no producen proteasas suficientes para que sean medidos por la metodología. Por lo tanto, estos resultados apoyan el uso de Lentinula edodes y Pleurotus sp para el desarrollo de potenciales aplicaciones en hidrólisis de proteínas en alimentos.(AU)

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RESUMO

A renina é um complexo natural de enzimas (endopeptidases aspárticas) utilizada na produção de queijos, extraída principalmente de estômagos de bezerros jovens. A maior demanda por queijos e o alto custo da renina têm incentivado a procura de fontes alternativas de proteases. Desse modo, o objetivo deste trabalho foi verificar as condições de tempo e temperatura para a produção de biomassa, exopolissacarídeos (EPS) e proteases por Pleurotus ostreatus em cultivo líquido. O micélio foi crescido em meio Pontecorvo, enriquecido com proteína isolada a 22, 25 ou 28oC, com amostragens aos 3, 6, 9, 14 e 17 dias de cultivo. A biomassa foi separada por centrifugação; EPS foram determinados por precipitação com etanol e a atividade proteolítica determinada pela ação do extrato enzimático sobre caseína solúvel alcalina 1% (m/v). Verificou-se que tanto o tempo quanto à temperatura afetaram (p<0,05) a produção de biomassa, EPS e proteases. Concluiu-se que a maior produção de biomassa de P. ostreatus ocorre após nove dias de cultivo a 25ºC; a produção de EPS aumenta com a ampliação do tempo de cultivo, com maior produção a 22ºC; e a máxima produção de proteases ocorre aos 14 dias de cultivo a 28ºC.

Rennet is a natural complex of enzymes (aspartic endopeptidases) and is often used in the production of cheese. Those enzymes (proteases) are extracted from abomasums of young ruminant animals. The high cheese demand associated with the high curdle cost have been stimulated the searching for alternative protease sources. The objective of this study was to verify the time and temperature conditions for biomass, exopolysaccharide (EPS) and protease production by Pleurotus ostreatus in liquid cultivation. The mycelium was grown in Pontecorvo medium added with isolated soy protein (5%) and maintained at 22, 25 or 28oC, with samplings at 3, 6, 9, 14 or 17 days of cultivation. The biomass was separated by centrifugation, EPS were separated by ethanol precipitation and the proteolytic activity was determined by enzymatic extract action on alkaline soluble casein 1% (m/v). It was verified that time and temperature affect (p<0.05) biomass, EPS and protease production. Most of P. ostreatus biomass production occurs after nine days of cultivation at 25°C. EPS production rise with increasing of cultivation time, with higher production at 22°C. Higher protease activity occurs at 28°C on 14 days of cultivation.

La renina es un complejo natural de enzimas (endopeptidasas aspárticas) utilizada en la producción de quesos, extraída principalmente de estómagos de becerros jóvenes. La mayor demanda por quesos y el alto costo de la renina ha incentivado la búsqueda de fuentes alternativas de proteasas. Así que, el objetivo de esta investigación fue verificar las condiciones de tiempo y temperatura para la producción de biomasa, exopolisacáridos (EPS) y proteasas por Pleurotus ostreatus en cultivo líquido. El micelio creció en medio a Ponte corvo, enriquecido con proteína aislada a 22, 25 o 28ºC, con muestras a los 3, 6, 9, 14 y 17 días de cultivo. Se separó la biomasa por centrifugación; EPS fueron determinados por precipitación con etanol y la actividad proteolítica determinada por la acción del estrato enzimático sobre caseína soluble alcalina 1% (m/v). Se verificó que tanto el tiempo como la temperatura afectaron (p<0,05) a la producción de biomasa, EPS y proteasas. Se concluye que la mayor producción de biomasa de P. ostreatus ocurre tras nueve días de cultivo a 25ºC; la producción de EPS aumenta con la ampliación del tiempo de cultivo, con mayor producción a 22ºC; y la máxima producción de proteasas ocurre a los 14 días de cultivo a 28ºC.

RESUMO

A renina é um complexo natural de enzimas (endopeptidases aspárticas) utilizada na produção de queijos, extraída principalmente de estômagos de bezerros jovens. A maior demanda por queijos e o alto custo da renina têm incentivado a procura de fontes alternativas de proteases. Desse modo, o objetivo deste trabalho foi verificar as condições de tempo e temperatura para a produção de biomassa, exopolissacarídeos (EPS) e proteases por Pleurotus ostreatus em cultivo líquido. O micélio foi crescido em meio Pontecorvo, enriquecido com proteína isolada a 22, 25 ou 28oC, com amostragens aos 3, 6, 9, 14 e 17 dias de cultivo. A biomassa foi separada por centrifugação; EPS foram determinados por precipitação com etanol e a atividade proteolítica determinada pela ação do extrato enzimático sobre caseína solúvel alcalina 1% (m/v). Verificou-se que tanto o tempo quanto à temperatura afetaram (p?0,05) a produção de biomassa, EPS e proteases. Concluiu-se que a maior produção de biomassa de P. ostreatus ocorre após nove dias de cultivo a 25ºC; a produção de EPS aumenta com a ampliação do tempo de cultivo, com maior produção a 22ºC; e a máxima produção de proteases ocorre aos 14 dias de cultivo a 28ºC.(AU)

Rennet is a natural complex of enzymes (aspartic endopeptidases) and is often used in the production of cheese. Those enzymes (proteases) are extracted from abomasums of young ruminant animals. The high cheese demand associated with the high curdle cost have been stimulated the searching for alternative protease sources. The objective of this study was to verify the time and temperature conditions for biomass, exopolysaccharide (EPS) and protease production by Pleurotus ostreatus in liquid cultivation. The mycelium was grown in Pontecorvo medium added with isolated soy protein (5%) and maintained at 22, 25 or 28oC, with samplings at 3, 6, 9, 14 or 17 days of cultivation. The biomass was separated by centrifugation, EPS were separated by ethanol precipitation and the proteolytic activity was determined by enzymatic extract action on alkaline soluble casein 1% (m/v). It was verified that time and temperature affect (p?0.05) biomass, EPS and protease production. Most of P. ostreatus biomass production occurs after nine days of cultivation at 25ºC. EPS production rise with increasing of cultivation time, with higher production at 22ºC. Higher protease activity occurs at 28ºC on 14 days of cultivation.(AU)

La renina es un complejo natural de enzimas (endopeptidasas aspárticas) utilizada en la producción de quesos, extraída principalmente de estómagos de becerros jóvenes. La mayor demanda por quesos y el alto costo de la renina ha incentivado la búsqueda de fuentes alternativas de proteasas. Así que, el objetivo de esta investigación fue verificar las condiciones de tiempo y temperatura para la producción de biomasa, exopolisacáridos (EPS) y proteasas por Pleurotus ostreatus en cultivo líquido. El micelio creció en medio a Ponte corvo, enriquecido con proteína aislada a 22, 25 o 28ºC, con muestras a los 3, 6, 9, 14 y 17 días de cultivo. Se separó la biomasa por centrifugación; EPS fueron determinados por precipitación con etanol y la actividad proteolítica determinada por la acción del estrato enzimático sobre caseína soluble alcalina 1% (m/v). Se verificó que tanto el tiempo como la temperatura afectaron (p?0,05) a la producción de biomasa, EPS y proteasas. Se concluye que la mayor producción de biomasa de P. ostreatus ocurre tras nueve días de cultivo a 25ºC; la producción de EPS aumenta con la ampliación del tiempo de cultivo, con mayor producción a 22ºC; y la máxima producción de proteasas ocurre a los 14 días de cultivo a 28ºC.(AU)

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