Microalgae extracts modulates the immune response in Trypanosoma cruzi-infected human cells.

Chagas disease (CD) is caused by the hemoflagellate protozoan Trypanosoma cruzi. The control of the infection depends of the innate and acquired immune response of host. Moreover, CD plays a significant role in the immune response, and, in this context, microalgae can be an interesting alternative due to its immunomodulatory and trypanocidal effects. This study aimed to evaluate, in vitro, immunomodulatory potentials of the aqueous extracts of Chlorella vulgaris and Tetradesmus obliquus. Both microalgae extracts (ME) were obtained by sonication, and the selectivity index (SI) was determined by assays of inhibitory concentration (IC50) in T. cruzi trypomastigotes cells; as well as the cytotoxic concentrations (CC50) in human peripheral mononuclear cells (PBMC). The immune response was evaluated in T. cruzi-infected PBMC using the IC50 value. ME led to inhibition of T. cruzi trypomastigotes after 24 h of treatment, in which the IC50 values were 112.1 µg/ml to C. vulgaris and 15.8 µg ml-1 to T. obliquus. On the other hand, C. vulgaris did not affect the viability of PBMCs in concentrations up to 1000 µg ml-1, while T. obliquus was non-toxic to PBMCs in concentrations up to 253.44 µg ml-1. In addition, T. obliquus displayed a higher SI against T. cruzi (SI = 16.8), when compared with C. vulgaris (SI = 8.9). C. vulgaris decreased the levels of IFN, indicating a reduction of the inflammatory process; while T. obliquus displayed an interesting immunomodulatory effect, since discretely increased the levels of TNF and stimulated the production of the anti-inflammatory cytokine IL-10. This study confirms that ME are effective against T. cruzi trypomastigotes, and may able to control the parasitemia and preventing the progress of CD while regulating the inflammatory process.

Evaluation of reference genes for gene expression analysis by real-time quantitative PCR (qPCR) in different tissues from mice infected by Ascaris suum.

Human ascariasis is the most prevalent helminth infection, affecting 445 million people worldwide. To better understand the impact of the immune system on the pathophysiology of individuals infected with Ascaris suum, mice have been used as experimental models. The RT-qPCR technique is a critical auxiliary tool of investigation used to quantify mRNA levels. However, proper normalization using reference genes is essential to ensure reliable outcomes to avoid analytical errors and false results. Despite the importance of reference genes for experimental A. suum infection studies, no specific reference genes have been identified yet. Therefore, we conducted a study to assess five potential reference genes (GAPDH, 18s, ACTB, B2M, and HPRT1) in different tissues (liver, lungs, small and large intestines) affected by A. suum larval migration in C57BL/6j mice. Tissue collection was carried out to analyze parasite burden and confirm the presence of larvae during the peak of migration in each tissue. Upon confirmation, we analyzed different genes in the tissues and found no common gene with stable expression. Our results highlight the importance of analyzing different genes and using different software programs to ensure reliable relative expression results. Based on our findings, B2M was ranked as the ideal reference gene for the liver, while 18S was the most stable gene in the lung and small intestine. ACTB, or a combination of ACTB with GAPDH, was deemed suitable as reference genes for the large intestine due to their stable expression and less variation between the control and infected groups. To further demonstrate the impact of using different reference genes, we normalized the expression of a chemokine gene (CXCL9) in all tissues. Significant differences in CXCL9 expression levels were observed between different groups in all tissues except for the large intestine. This underscores the importance of selecting appropriate reference genes to avoid overestimating target gene expression levels and encountering normalization-related issues that can lead to false results. In conclusion, our study highlights the significance of using reliable reference genes for accurate RT-qPCR analysis, especially in the context of A. suum infection studies in different tissues. Proper normalization is crucial to ensure the validity of gene expression data and avoid potential pitfalls in interpreting results.

Toxicological assays in the evaluation of safety assessment of fibrinolytic enzymes.

Cardiovascular diseases (CVDs) cause 30% of deaths each year, and in 2030, around 23.6 million people will die due to CVDs. The major challenge is to obtain molecules with minimal adverse reactions that can prevent and dissolve blood clots. In this context, fibrinolytic enzymes from diverse microorganism sources have been extensively investigated due to their potential to act directly and specifically on the fibrin clot, preventing side effects and performing potential thrombolytic effects. However, most researches focus on the purification and characterization of proteases, with little emphasis on the mechanism of action and pharmacological characteristics, including toxicity assays which are essential to assess safety and side effects. Therefore, this work aims to emphasize the importance of evaluations indicating the toxicological profile of fibrinolytic proteases through in vitro and in vivo tests. Both types of assays contribute as preclinical stage in drug development and are crucial for clinical applications. This scarcity creates arbitrary barriers to further studies. This work should further encourage the development of studies to ensure the safety and effectivity of fibrinolytic proteases.

Suggested pre-clinical trials aim to validate more specific methods for fibrinolytic enzymes;Current toxicity standards can be adapted to better assess the profile of fibrinolytic enzymes;The class of fibrinolytic enzymes must be carefully evaluated according to the method of application.

Extracellular collagenase isolated from Streptomyces antibioticus UFPEDA 3421: purification and biochemical characterization.

Collagenases are proteases able to degrade native and denatured collagen, with broad applications such as leather, food, and pharmaceutical industries. The aim of this research was to purify and characterize a collagenase from Streptomyces antibioticus. In the present work, the coffee ground substrate provided conditions to obtaining high collagenase activity (377.5 U/mL) using anion-exchange DEAE-Sephadex G50 chromatographic protocol. SDS-PAGE revealed the metallo-collagenase with a single band of 41.28 kDa and was able to hydrolyzed type I and type V collagen producing bioactive peptides that delayed the coagulation time. The enzyme activity showed stability across a range of pH (6.0-11) and temperature (30-55 °C) with optima at pH 7.0 and 60 °C, respectively. Activators include Mg+2, Ca+2, Na+, K+, while full inhibition was given by other tested metalloproteinase inhibitors. Kinetic parameters (Km of 27.14 mg/mol, Vmax of 714.29 mg/mol/min, Kcat of 79.9 s-1 and Kcat/Km of 2.95 mL/mg/s) and thermodynamic parameters (Ea of 65.224 kJ/mol, ΔH of 62.75 kJ/mol, ΔS of 1.96 J/mol, ΔG of 62.16 kJ/mol, ΔGE-S of 8.18 kJ/mol and ΔGE-T of -2.64 kJ/mol) were also defined. Coffee grounds showed to be an interesting source to obtaining a collagenase able to produce bioactive peptides with anticoagulant activity.

Recovery and partial purification of fibrinolytic protease from Pleurotus ostreatus and P. eryngii and cytotoxic and antioxidant activity of their extracts.

Mushrooms are a source of primary and secondary metabolites. Little is known about the most suitable conditions for production of mushrooms by submerged fermentation. This article reports antioxidant and cytotoxic assays, in addition to quantitatively evaluating the content of proteases with fibrinolytic action in the crude extracts of two species of edible mushrooms produced in different formulations, as well as evaluating the recovery of these enzymes by aqueous two-phase systems (ATPS). The mushrooms Pleurotus ostreatus and Pleurotus eryngii, at concentration of 100 µg/mL, displayed inhibition of DPPH and ABTS radicals below 50%. In the cytotoxicity test, the cells human fibroblast cell lines (MRC-5) showed cell viability greater than 80%. Concerning fibrinolytic activity, P. eryngii presented 226.47 ± 7.26 U/mL, therefore being more efficient than P. ostreatus (71.5 ± 0.56 U/mL). In the recovery of the P. eryngii extract by ATPS, the fibrinolytic protease was partitioned in the salt phase (30.25 U/mL). The molecular mass of the proteases was between 75 and 100 kDa. These results prove the low cytotoxicity of the extracts produced and that fermentation in supplemented malt broth favored the excretion of fibrinolytic proteases compared to the other evaluated media.

Cost-effective fibrinolytic enzyme production by microalga Dunaliella tertiolecta using medium supplemented with corn steep liquor.

A fibrinolytic enzyme from the microalga Dunaliella tertiolecta was produced under mixotrophic conditions using different corn steep liquor (CSL) concentrations ( 0 ≤ CLS ≤ 0.75%), purified using a combination of salting out and ion-exchange chromatography, and then biochemical characterized. Cultivation of this microalga using 0.5% CSL led to the highest maximum cell concentration (1.960±0.010 mg L-1) and cell productivity (0.140g L-1 day-1), besides a high fibrinolytic activity of the extract obtained by the homogenization method (102 ±1 U mL-1). The enzyme extracted from the microalgal biomass was 5-fold purified with a 20% yield and was found to have a specific activity of 670 U mg-1. The enzyme, whose molecular weight determined by fibrin zymography was 10 kDa, was shown to be stable at pH 3.0-9.0 and up to 70°C with optimal pH and temperature values of 8.0 and 50°C, respectively. When compared to other fibrinolytic enzymes, this protease stood out for its high fibrinolytic activity, which was enhanced by Fe2+, inhibited by Zn2+, Cu2+, Mg2+, and Ca2+, and strongly inhibited by phenylmethylsulfonyl fluoride, suggesting that it belongs to the serine metalloprotease family. Moreover, thanks to its thermal stability, the enzyme may be easily preserved and activated under high-temperature conditions.

Extraction of collagenolytic proteases from Aspergillus heteromorphus URM 0269 in an aqueous two-phase system for application in collagen hydrolysis.

Collagenolytic proteases produced by Aspergillus heteromorphus URM0269 were extracted using a PEG/sulfate aqueous two-phase system (ATPS). A 23 factorial design was performed to analyze the independent variables: PEG molar mass (MPEG), PEG concentration (CPEG), and sulfate concentration (Csulf). The extracted proteases were also evaluated for their optimum pH and stability at different pH levels (4.0 - 11.0) after 20 h of incubation. Collagen was extracted from mutton snapper (Lutjanus analis) skin using acetic acid (0.5 mol L-1). The enzyme was preferentially partitioned to the PEG-rich phase (K > 1), whose highest purification factor and recovery (PF = 6.256 and Y = 404.432%) were obtained under specific conditions: MPEG 8000 g.mol-1, CPEG 30%, Csulf 10%. The ATPS extraction provided an enzymatic activity range of pH 7.0 - 11.0, exhibiting greater stability compared to the crude extract. Approximately 80% of protease activity was maintained after 20 hours of incubation at all analyzed pH levels, except pH 11.0. Collagen extraction from L. analis skin yielded 8.056%, and both crude extract samples and ATPS-derived samples successfully hydrolyzed the extracted collagen, reaching peak hydrolysis after 36 hours of treatment. These findings demonstrate the feasibility of extracting highly purified and active proteases capable of hydrolyzing L. analis collagen.

A novel ß-fructofuranosidase produced by Penicillium citreonigrum URM 4459: purification and biochemical features.

Fructooligosaccharides (FOS) are prebiotics of interest to the food industry. These compounds can be produced through the transfructosylation reaction by the enzyme fructofuranosidase. This enzyme is widely produced by fungi in a medium rich in sugar. Therefore, in this work, the main objectives were production, purification, biochemical characterization of a novel fructofuranosidase enzyme by Penicillium citreonigrum URM 4459 and synthesize and evaluate the antibacterial potential of fructooligosaccharides. With respect to sucrose hydrolysis, the optimal pH was 5.5, the apparent Km for purified FFase was 3.8 mM, the molecular mass was 43.0 kDa, estimated by gel filtration on Superdex increase G75 controlled by AKTA Avant 25 and confirmed by 10% SDS-PAGE under denaturing condition. Also, the isoelectric point was 4.9. The fractions obtained with enzymatic activities, both stable at acidic pH and high temperatures, as well as being able to produce FOS. Regarding antibacterial activity, the FOS produced in this study showed better results than commercial FOS and other carbon sources. Thus, this work presents relevant data for the use of P. citreonigum to produce fructofuranosidase and consequently FOS and can be used in the food and pharmaceutical industry.

Purification, biochemical characterization and fibrinolytic potential of proteases produced by bacteria of the genus Bacillus: a systematic literature review.

Thrombosis is a hematological disorder characterized by the formation of intravascular thrombi, which contributes to the development of cardiovascular diseases. Fibrinolytic enzymes are proteases that promote the hydrolysis of fibrin, promoting the dissolution of thrombi, contributing to the maintenance of adequate blood flow. The characterization of new effective, safe and low-cost fibrinolytic agents is an important strategy for the prevention and treatment of thrombosis. However, the development of new fibrinolytics requires the use of complex methodologies for purification, physicochemical characterization and evaluation of the action potential and toxicity of these enzymes. In this context, microbial enzymes produced by bacteria of the Bacillus genus are promising and widely researched sources to produce new fibrinolytics, with high thrombolytic potential and reduced toxicity. Thus, this review aims to provide a current and comprehensive understanding of the different Bacillus species used for the production of fibrinolytic proteases, highlighting the purification techniques, biochemical characteristics, enzymatic activity and toxicological evaluations used.

Immobilization of fibrinolytic protease from Mucor subtilissimus UCP 1262 in magnetic nanoparticles.

This work reports the immobilization of a fibrinolytic protease (FP) from Mucor subtilissimus UCP 1262 on Fe3O4 magnetic nanoparticles (MNPs) produced by precipitation of FeCl3·6H2O and FeCl2·4H2O, coated with polyaniline and activated with glutaraldehyde. The FP was obtained by solid state fermentation, precipitated with 40-60% ammonium sulfate, and purified by DEAE-Sephadex A50 ion exchange chromatography. The FP immobilization procedure allowed for an enzyme retention of 52.13%. The fibrinolytic protease immobilized on magnetic nanoparticles (MNPs/FP) maintained more than 60% of activity at a temperature of 40 to 60 °C and at pH 7 to 10, when compared to the non-immobilized enzyme. MNPs and MNPs/FP did not show any cytotoxicity against HEK-293 and J774A.1 cells. MNPs/FP was not hemolytic and reduced the hemolysis induced by MNPs from 2.07% to 1.37%. Thrombus degradation by MNPs/FP demonstrated that the immobilization process guaranteed the thrombolytic activity of the enzyme. MNPs/FP showed a total degradation of the γ chain of human fibrinogen within 90 min. These results suggest that MNPs/FP may be used as an alternative strategy to treat cardiovascular diseases with a targeted release through an external magnetic field.

Brazilian perspective: antimicrobial stewardship in solid organ transplant.

BACKGROUND: The incidence of multidrug resistant organisms (MDROs) infections among solid organ transplant (SOT) patients is very high in Brazil. METHODS: This review will discuss antimicrobial use and resistance in SOT in Brazil, highlighting the main barriers and facilitators for implementation of an antimicrobial stewardship programme (ASP). RESULTS: The most common group of MDROs is carbapenem-resistant Gram-negative bacteria and vancomycin-resistant Enterococcus. Carbapenem-resistant Enterobacterales (CREs) are the most frequent MDROs and have been reported as donor-derived as well. Although ASPs are mandatory in the country, there is a lack of information regarding ASPs in SOT recipients. The main barriers for the implementation of ASPs in Brazilian hospitals are lack of electronic medical records, absence of national guidelines specific to SOT recipients, lack of recommendations on surveillance culture to evaluate colonization and transmission of donor-derived MDROs, limited availability of rapid diagnostic tests, and insufficient pharmacist and clinician time allocated to ASP activities in some SOT centers. CONCLUSIONS: The incidence of MDRO infections caused mainly by VREs and CREs is very high in the country. There is limited data regarding antimicrobial use among SOT recipients in Brazil. The absence of antimicrobial stewardship national guidelines specific to SOT recipients is one of the main barriers for the implementation of ASPs in Brazilian hospitals.

Photosynthetic microorganisms and their bioactive molecules as new product to healing wounds.

Wounds are a public health problem due to long periods required to repair damaged skin, risk of infection, and amputations. Thus, there is a need to obtain new therapeutic agents with less side effects, more effective oxygen delivery, and increased epithelial cell migration. Photosynthetic microorganisms, such as microalgae and cyanobacteria, may be used as a source of biomolecules for the treatment of different injuries. The aim of this review article focuses on healing potential using phytoconstituents from photosynthetic microorganisms. Cyanophyte Spirulina and Chlorophyte Chlorella are more promising due to steroids, triterpenes, carbohydrates, phenols, and proteins such as lectins and phycocyanin. However, there are few reports about identification and specific function of these molecules on the skin. In other microalgae and cyanobacteria genus, high contents of pigments such as ß-carotene, chlorophyll a, allophycocyanin, and hydroxypheophytin were detected, but their effects on phases of wound healing is absent yet. The development of new topical drugs from photosynthetic microorganisms could be a potential alternative to maximize healing. KEY POINTS: • Conventional treatment to skin injuries has limitations. • Proteins, terpenes, and phenols increase collagen deposition and re-epithelialization. • Microalgae and cyanobacteria may be used as a source of biomolecules to wound healing.

Algae as a source of peptides inhibitors of the angiotensin-converting enzyme: a systematic review.

Hypertension is a factor that contributes to the risk of chronic diseases. The inhibition of angiotensin-I converting enzyme (ACE) is a useful therapeutic approach to the hypertension treatment. The algae have been an alternative for the production of ACE inhibitory (ACEi) peptides from enzymatic hydrolysis due to their protein-rich biomass. The aim of this study was to systematically review the literature regarding the production, composition and activity of ACEi peptides derived from algae proteins. Systematic database searches identified 648 related articles. Among these, only 14 were selected according to the eligibility criteria to this review. Macroalgae are more studied than microalgae as sources of ACEi peptides. Furthermore, hydrolysates by thermolysin or bromelain exhibited the highest ACEi activity compared to other enzymes. The main features of the peptides with high ACE inhibition are low molecular weight, short amino acids sequence and non-competitive inhibition pattern. In vivo studies using hydrolysates and peptides derived from algae proteins showed antihypertensive activity in spontaneously hypertensive rats (SHR). Thus, it is suggested that ACEi peptides derived from algae can be considered as potential antihypertensive.

In silico evaluation of genomic characteristics of Streptococcus infantarius subsp. infantarius for application in fermentations.

This study aims to evaluate the in silico genomic characteristics of Streptococcus infantarius subsp. infantarius, isolated from Coalho cheese from Paraíba, Brazil, with a view to application in lactic fermentations. rRNA sequences from the 16S ribosomal region were used as input to GenBank, in the search for patterns that could reveal a non-pathogenic behavior of S. infantarius subsp. infantarius, comparing mobile genetic elements, antibiotic resistance genes, pan-genome analysis and multi-genome alignment among related species. S. infantarius subsp. infantarius CJ18 was the only complete genome reported by BLAST/NCBI with high similarity and after comparative genetics with complete genomes of Streptococcus agalactiae (SAG153, NJ1606) and Streptococcus thermophilus (ST106, CS18, IDCC2201, APC151) revealed that CJ18 showed a low number of transposases and integrases, infection by phage bacteria of the Streptococcus genus, absence of antibiotic resistance genes and presence of bacteriocin, folate and riboflavin producing genes. The genome alignment revealed that the collinear blocks of S. thermophilus ST106 and S. agalactiae SAG153 have inverted blocks when compared to the CJ18 genome due to gene positioning, insertions and deletions. Therefore, the strains of S. infantarius subsp. infantarius isolated from Coalho cheese from Paraíba showed genomic similarity with CJ18 and the mobility of genes analyzed in silico showed absence of pathogenicity throughout the genome of CJ18, indicating the potential of these strains for the dairy industry.

Histomorphometric analysis of the lung of Swiss mice treated with a fibrinolytic protease.

Fibrinolytic enzymes are considered promising alternative in the treatment of cardiovascular diseases by preventing fibrin clots. A protease from Mucor subtilissimus UCP 1262 was obtained by solid state fermentation and purified by ion exchange chromatography. The purified extract was administered at an acute dose of 2000 mg/mL to evaluate its toxic effects to the lungs of mice. After 14 days of treatment, a histomorphometric study was performed by the type 1 and 2 pneumocyte count and the evaluation of the lung area. As result, the experimental group showed a significant decrease of type 2 pneumocyte and although a decrease in the alveolar area was observed in relation to the control group, no significant pulmonary toxicity, emphysema, and fibrosis characteristics were detected. The in vitro tests suggest possible clinical applications for the enzyme.

A novel collagenolytic protease from Mucor subtilissimus UCP 1262: Comparative analysis of production and extraction in submerged and stated-solid fermentation.

This work aimed to compare the production of collagenolytic proteases produced by M. subtilissimus UCP1262 in submerged fermentation (SF) and solid-state fermentation (SSF) as well as extracting in aqueous two-phase system (ATPS). Collagenolytic protease production was performed in using MS-2 culture medium (SF) and soybean bran as substrate (SSF). Subsequently, the fermented liquid from both fermentations were used for the extraction of enzyme by ATPS, it was verified the influence of different variables from a factorial design 23. In SSF the highest protease and collagenolytic activities were achieved with 362.66 U/mL and 179.81 U/mL, respectively. When compared with SF (26.33 and 18.70 U/mL) higher values were obtained in the activities. The protease partitioning from SF and SSF in ATPS showed a similar profile showing higher affinity for the polymer rich phase. The highest value for the response variable purification factor (3.49) was obtained in the system using SSF. Thus, SSF shows promise as a bioprocess for extracellular production of collagenolytic proteases, using of soybean bran as substrate had used sustainable raw material, aiming application this possible enzyme in the treatment of burns and postoperative scarring.

Extractive fermentation for process integration of protease production by Aspergillus tamarii Kita UCP1279 and purification by PEG-Citrate Aqueous Two-Phase System.

The present study evaluated the influence of the variables polyethylene glycol (PEG) molar mass, pH, PEG concentration and sodium citrate concentration in the integrated production of the protease from Aspergillus tamarii Kita UCP1279 by extractive fermentation, obtaining as a response the partition coefficient (K), activity yield (Y) and concentration factor (CF). The enzyme preferably partitioned to the top phase and obtained in the system formed by variables MPEG = 400 g mol-1, CPEG = 20% (w w-1), and CCIT = 20% (w w-1) and pH 6, in this condition were obtained CF = 1.90 and Y = 79.90%. The protease showed stability at a temperature of 60 °C for 180 min, with optimum temperature 40 °C and pH 8.0. For the ions and inhibitors effects, the protease activity increased when exposed to Fe2+, Ca2+ and Zn2 + and inhibited by EDTA, being classified as metalloprotease. The kinetic parameters Km (35.63 mg mL-1) and Vmax (1.205 mg mL-1 min-1) were also estimated. Thus, the protease showed desirable characteristics that enable future industrial applications, especially, for beer industry.

Structural and functional analysis of broad pH and thermal stable protease from Penicillium aurantiogriseum URM 4622.

This study aimed to better characterize a recently purified stable extracellular alkaline peptidase produced by Penicillium aurantiogriseum (URM 4622) through fluorescence spectroscopy, far-UV circular dichroism, kinetic and thermodynamic models to understand its' structure-activity and denaturation. Fluorescence data showed that changing pH leads to tryptophan residues exposure to more hydrophilic environments at optimum activity pH 9.0 and 10.0. When thermally treated, it displayed less unfolding at these pH values, along with 4-fold less photoproducts formation than at neutral pH. Different pH CD spectra showed more ß-sheet (21.5-43.0%) than α-helix (1-6.2%). At pH9.0, more than 2-fold higher α-helix content than any other pH. The melting temperature (Tm) was observed between 50 and 60 °C at all pH studied, with lower Tm at pH 9.0-11.0 (54.9-50.3 °C). The protease displayed two phase transition, with two energies of denaturation, and a 4-fold higher thermal stability (ΔH°m) than reports for other microorganism's proteases. An irreversible folding transition occurs between 50 and 60 °C. It displayed energies of denaturation suggesting higher thermal stability than reported for other microorganism's proteases. These results help elucidating the applicability of this new stable protease.

First report of collagenase production by Trichosporon sp. strain isolated from pollen of Amazonian bee (Melipona seminigra seminigra).

Trichosporon yeasts are widely employed to produce lipids, lipases, and aspartic peptidases, but there are no previous studies on collagenase production. This work aimed to select the best collagenase producing Amazonian Trichosporon strains. Moreover, a 23-full factorial design (FFD) and a 22-central composite design combined with Response Surface Methodology were applied to optimize production and find the best conditions for hydrolysis of type I bovine collagen. Most of the studied strains had some collagenolytic activity, but the selected one achieved the highest value (44.02 U) and a biomass concentration of 2.31 g/L. The best collagenase production conditions were 160 rpm of agitation, pH 5.5 and a substrate concentration of 4.0 g/L. The former experimental design showed that substrate concentration was the only statistically significant factor on both biomass concentration and collagenase activity, while the latter showed simultaneous effects of substrate concentration and pH on collagenolytic activity, which peaked at pH 5.5-6.4 and substrate concentration of 3.0-3.4 g/L. An additional 2³-FFD was finally used to optimize the conditions collagen hydrolysis, and pH 6, 25 °C and a substrate concentration of 7.5 (g/L) ensured the highest hydrolysis degree. This study is the first that describes optimized conditions of collagenase production by Trichosporon strains.

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Seroprevalence and Risk Factors Among Oligo/Asymptomatic Healthcare Workers: Estimating the Impact of Community Transmission.

We evaluated the seroprevalence of SARS-CoV-2 and risk factors among 4987 oligo/asymptomatic healthcare workers; seroprevalence was 14% and factors associated with SARS-CoV-2 infection were lower educational level (aOR, 1.93; 95% CI, 1.03-3.60), using public transport to work (aOR, 1.65; 95% CI, 1.07-2.62), and working in cleaning or security (aOR, 2.05; 95% CI, 1.04-4.03).