STORAGE RESULTS IN LOSS OF THE ANTIGENOTOXIC PROPERTIES OF LENTINULA EDODES (SHIITAKE MUSHROOM) AND DEVELOPMENT OF IN VIVO GENOTOXICITY

In this study, we have investigated the stability of the antigenotoxic properties of dried of Lentinula edodes (Berk.) Singer mushroom powder stored at room and at − 20C. Mice were pretreated by gavage for 15 consecutive days with 0.6 mL/day of an aqueous extract of dried L. edodes powder prepared at 60C. On day 15, the mice were intraperitoneally injected with 50 mg/kg N-ethyl-N-nitrosourea (ENU); 3 h later, peripheral blood was withdrawn from the animals and used to evaluate DNA damage using the comet assay. The mice were sacrificed 24 h after the ENU treatment and the bone marrow used to measure the frequency of micronucleated polychromatic erythrocytes. The results indicated that storage at both room temperature and at − 20C significantly reduced the antigenotoxic effects of the mushroom powder. In addition, whereas freshly dried mushroom powder was nongenotoxic, storage of the powder at − 20C resulted in genotoxic activity ( P <  0.05). Taken together, our data indicate that constituents of L. edodes powder are altered during storage, resulting in both genotoxicity and a reduction in antigenotoxicity.     

SARS-CoV-2 induced myocarditis: Current knowledge about its molecular and pathophysiological mechanisms

The existence of an inflammatory process in the heart muscle, related to a progressive worsening of myocardial function, different etiopathogenetic mechanisms concur and often overlap, thus making the diagnosis and the therapeutic approach complex. As the COVID-19 pandemic progresses, the effects of the disease on the organ systems and in particular on the cardiovascular system are becoming more and more profound. Cardiac involvement is a well-known event with a high percentage of findings in the heart’s magnetic field, even in asymptomatic areas. There are numerous uncertainties regarding their evolution, in the long and short term, due not only to a difficult to determine the varied clinical expression and the rarely performed intramyocardial biopsy which additionally presents diagnostic problems but also in part to different clinical prognosis. Today, the new SARS-CoV-2 virus that uses the angiotensin converting enzyme 2 (ACE2) which is present at high levels in myocardial cells as its entrance it can create even severe heart injury. The pathophysiology in all of these cases can involve multiple immune and non-immune mechanisms within organs and vessels and can be occur in the clinical phases. Possible mechanisms of direct and indirect myocardial infarction in patients with COVID-19 include additional lesion and oxygen-rich and generalized inflammation response with myocardial immune hyperactivity (myocarditis). Therefore, these can occur through the excessive release of cytokines, the presence of thrombocytopenia, endocrine damage, heart failure, arrhythmias and more. Patients can show average signs of myocardial damage, and some develop spontaneous cardiac complications, such as heart failure, arrhythmias and, rarely, rare cardiogenic disorders. Pathophysiology in all of these may involve multiple mechanisms within the cytokine cephalic membrane, endocrine damage and thrombogenicity. The diagnosis of this myocardial injuri is mainly based on the myocardial enzyme troponin. This viewpoint paper explains today’s knowledge on viral myocarditis, in particular that from SARS-CoV-2 infection, if there is a connection with other possible biomolecular pathogenetic factors that can influence its natural course. In fact, it is for this reason that the pathogenetic mechanisms are analyzed and described. At the same time, its possible interaction with other parameters that are documented risk factors for cardiovascular disease was examined. Although these biomolecular findings were mainly related to necrotic parts of the myocardium, it is important to recognize that myocardial damage early for a better approach and prognosis.     

EFFECTS OF FEED DIETS ON DIGESTIVE PROTEASES FROM THE HEPATOPANCREAS OF WHITE SHRIMP (Penaeus vannamei)

Protease activities in the hepatopancreas extract (HP) from white shrimp (Penaeus vannamei) fed one of seven test diets for 30 days were evaluated by several methods. The test diet contained 85% of a reference ration for shrimp and 15% of either anchovy meal, tuna waste meal, deboned white fish meal, langostilla meal, soybean meal, and two menhaden meals as a protein replacer. One of the menhaden fish meals tested (B) had the lowest quality as a shrimp feed based on amino acid analysis. SDS-PAGE zymograms of HP from each of the seven diet groups showed similar proteins activity patterns with casein as substrate. The degree of hydrolysis of casein, measured by pH-stat, was also the same for HP from the seven diet groups (P > 0.05). However, total protease activity measured by azocasein hydrolysis (units/g HP) was higher for the diet group fed the test ration containing tuna waste as a replacer (P > 0.05). Trypsin and chymotrypsin activities measured with synthetic substrates (units/mg protein; units/g HP) from animals reared on the diet with menhaden meal B replacer were greater than in the other diet groups (P < 0.05). This study shows that a relatively small amount (15%) of a specific protein replacer in white shrimp rations can influence the protease activity of shrimp HP. Given that digestive proteases such as trypsin can leach into the muscle of postharvest shrimp and thereby cause softening of the meat, the impact of the rearing diet on postharvest shelf-life should be considered along with the standard measures of feed quality that are used by the fish farmer, i.e. animal growth and heatlh.     

Impact of different pasteurization temperatures on the survival of microbial contaminants isolated from pasteurized milk

The thermal inactivation of selected microbes was studied using the low temperature long time (LTLT), high temperature short time (HTST) and 'pot' pasteurization methods. Survivors were enumerated after heating for up to 40 min for the LTLT and HTST pasteurization methods and after heating for up to 30 min for the 'pot' pasteurization method. With the exception of the Bacillus cereus strain, the selected microbes did not survive the LTLT and HTST pasteurization methods. The results from the 'pot' pasteurizer showed that B. cereus, Chryseobacterium meningosepticum, Pseudomonas putida, Acinetobacter baumannii and Escherichia coli strains survived the pasteurization conditions applied, showing that the 'pot' pasteurizer does not pasteurize effectively.     

EFFECT OF FEED DIET ON AMINOPEPTIDASE ACTIVITIES FROM THE HEPATOPANCREAS OF WHITE SHRIMP (PENAEUS VANNAMEI)

White shrimp (Penaeus vannamei) were fed one of seven diets for 30 days. Diets contained 85% of a reference ration and 15% of either anchovy, tuna waste meal, deboned fish meal, langostilla crab meal, soybean meal, menhaden meal A, or menhaden B as a protein replacer. At the end of the feeding trial, animals were sacrificed and 10 aminopeptidase activities of the hepatopancreas tissue were assayed. The hepatopancreas tissues contained Arg-, Leu-, His-, Ile-, Lys-, Met-, Thr- and Val-aminopeptidase activities but no activity was detected for Phe-aminopeptidase. Leu-aminopeptidase activity was inhibited by Zn⁺² and Mg⁺² salts and activity was also inhibited when more than 0.2 mg of hepatopancreas extract protein was included in the assay. Principal component analysis was used to determine whether diet had an influence on hepatopancreas
aminopeptidase activities. The aminopeptidase activities were greater for animals fed a diet containing menhaden fish meal B. This was principally the result of the higher levels of Met-, Val-, Pro-, Lys-, and Leu-aminopeptidase activities in animals fed menhaden fish meal. Menhaden fish meal B had a lower nutritional quality for shrimp than the other protein replacers. Seven of the 10 essential amino acids for shrimp were present at less than 100% of the recommended values. On the other hand, shrimp fed soybean meal replacer contained lower amounts of aminopeptidase activity, notably Gly- and Met-aminopeptidase activities, and the meal was of excellent quality having only one limiting amino acid. The results indicate that the shrimp diet can influence proteolytic activity of the hepatopancreas tissue. This is significant to the seafood technologist since previous studies showed that hepatopancreas proteases can leach into the meat postmortem and cause tissue softening.     

Thermal resistance of aerobic spore formers isolated from food products

The heat resistance of aerobic spore formers isolated from dairy products and cocoa powder was examined to give an overview of occurring highly heat‐resistant spores. Experiments were conducted in phosphate buffer at different temperatures for 30 min. Two Geobacillus pallidus strains survived the heat treatment at 125 °C with log reductions of 6.68 and 6.73. Furthermore, the inactivation kinetics of one of these strains (Bacillus amyloliquefaciens) were determined using a modified Arrhenius model. The inactivation followed a reaction order of 1 with a reaction rate constant (k_ref) of 0.085/s at 394 K and an activation energy (E_a) of 209 kJ/mol.     

Precise tissue bioengineering and niches of mesenchymal stem cells: Their size and hierarchy matter

Stem cell microterritories (niches), as a specialized part of the extracellular matrix (ECM), are considered an important target and tool for the development of new materials, medical implants, and devices. However, tissue bioengineering products that have stem cell niches of known size on the surface or in the bulk structure of artificial materials are practically unknown. This brief review attempts to draw attention to the problematic aspects of niches as specific parts of the ECM, such as their hierarchy and size for mesenchymal stromal/stem cells (MSCs). These parameters arise directly from numerous definitions of stem cell niches as specialized morphological microterritories found in various tissues. The authors of this review analyze the known information on the hierarchy of MSC microterritories by analogy with that of hematopoietic stem cells. Occasional reports on the size of artificial MSC niches compared to natural niche candidates are summarized. A consensus on a hierarchy and optimal range of niche sizes for MSCs and other stem cells is needed to accelerate the development of prototyping technologies and additive manufacturing in applications to precise tissue bioengineering and regenerative medicine.     

Cherimoya (Annona cherimola Mill) Polyphenoloxidase: Monophenolase and Dihydroxyphenolase Activities

Polyphenoloxidase (PPO) from cherimoya epicarp catalyzed the hydroxylation of monphenols like L(?)tyrosine, tyramine, and p-cresol (monophenolase activity), and oxidation of o-dihydroxyphenols like catechol and L-DOPA (dihydroxyphenolase activity). The hydroxylation of monophenols occurred after a lag period which was shortened by diphenols. The Km values indicated a low affinity of PPO to the substrates. Aliphatic mono- and dicarboxylic acids and sugars did not show any inhibitory effect on PPO cherimoya epicarp. Cysteine and mercaptoethanol, but not ascorbic acid, appeared to be protective agents of PPO cherimoya epicarp.