Resistant Starch Content and Structural Changes in Maize (Zea mays) Tortillas During Storage

Storage of maize products such as tortillas may cause starch retrogradation and lead to resistant starch (RS) formation. This study was carried out to determine if storage of maize tortillas under refrigerated conditions enhanced RS content and/or modified RS structure. Improved Costeño variety maize grain was nixtamalized and processed into tortillas which were stored for five and ten days at 5°C. Total resistant starch (TRS) and retrograded resistant starch (RRS or RS3) contents were determined on raw and nixtamalized maize grain and tortillas stored for zero, five and ten days. Differential scanning calorimetry (DSC), X‐ray diffraction (XRD) and near‐infrared (NIR) spectroscopy were use to evaluate structural changes in retrograded resistant starch isolated from each sample type. Total starch content was 67 ± 1.5% for all samples, TRS ranged from 3.3% in the raw grain at 7.2% in tortillas stored for ten days, while RRS starch content ranged from 0% in the raw grain to 3.2% in tortillas stored for ten days. DSC showed endothermic transitions corresponding to amylopectin and amylose retrogradation, at 31.9 and 139.7°C in RRS from tortillas stored for five days, and at 47.9 and 146°C in RRS from tortillas stored for ten days. These values agreed with the higher total RS content recorded after prolonged storage. XRD revealed a starch crystallinity of 13.7% in tortillas stored for five days and 15.3% in those stored for ten days. NIR spectroscopy analysis showed evidence of structural changes in polymeric order that were more pronounced in RRS of tortillas stored for ten days, due to increase in crystalline region.     

Development of a PCR-restriction fragment length polymorphism protocol for rapid detection and differentiation of four cockroach vectors (group I "Dirty 22" species) responsible for food contamination and spreading of foodborne pathogens: public health importance

Assessing the adulteration of food products and the presence of filth and extraneous materials is one of the measures that the U.S. Food and Drug Administration (FDA) utilizes in implementing regulatory actions of public health importance. To date, 22 common pest species (also known as the "Dirty 22" species) have been regarded by this agency as the spreaders of foodborne diseases. We have further categorized the Dirty 22 species into four groups: I has four cockroach species, II has two ant species, III has 12 fly species, and IV has four rodent species. The presence of any Dirty 22 species is also considered an indicator of unsanitary conditions in food processing and storage facilities. In this study, we describe the development of a two-step nested PCR protocol to amplify the small subunit ribosomal gene of group I Dirty 22 species that include four cockroach species: Blattella germanica, Blatta orientalis, Periplaneta americana, and Supella longipalpa, along with the development of a PCR-restriction fragment length polymorphism method for rapid detection and differentiation of these violative species. This method will be utilized when the specimen cannot be identified with conventional microscopic taxonomic methods, especially when only small body parts are separated and recovered from food samples for analysis or when these body parts are in a decomposed state. This new PCR-restriction fragment length polymorphism will provide correct identification of group I Dirty 22 species; this information can then be used in regulation and prevention of foodborne pathogens.     

Saccharomyces cerevisiae and Hanseniaspora uvarum mixed starter cultures: Influence of microbial/physical interactions on wine characteristics

The growing trend in the wine industry is the revaluation of the role of non-Saccharomyces yeasts, promoting the use of these yeasts in association with Saccharomyces cerevisiae. Non-Saccharomyces yeasts contribute to improve wine complexity and organoleptic composition. However, the use of mixed starters needs to better understand the effect of the interaction between these species during alcoholic fermentation. The aim of this study is to evaluate the influence of mixed starter cultures, composed by combination of different S. cerevisiae and Hanseniaspora uvarum strains, on wine characteristics and to investigate the role of cell-to-cell contact on the metabolites produced during alcoholic fermentation. In the first step, three H. uvarum and two S. cerevisiae strains, previously selected, were tested during mixed fermentations in natural red grape must in order to evaluate yeast population dynamics during inoculated fermentation and influence of mixed starter cultures on wine quality. One selected mixed starter was tested in a double-compartment fermentor in order to compare mixed inoculations of S. cerevisiae/H. uvarum with and without physical separation. Our results revealed that physical contact between S. cerevisiae and H. uvarum affected the viability of H. uvarum strain, influencing also the metabolic behaviour of the strains. Although different researches are available on the role of cell-to-cell contact-mediated interactions on cell viability of the strains included in the mixed starter, to our knowledge, very few studies have evaluated the influence of cell-to-cell contact on the chemical characteristics of wine.     

Transferable Antibiotic Resistances in Marketed Edible Grasshoppers (Locusta migratoria migratorioides)

Grasshoppers are the most commonly eaten insects by humans worldwide, as they are rich in proteins and micronutrients. This study aimed to assess the occurrence of transferable antibiotic resistance genes in commercialized edible grasshoppers. To this end, the prevalence of 12 selected genes [aac(6’)‐Ie aph(2″)‐Ia, blaZ, erm(A), erm(B), erm(C), mecA, tet(M), tet(O), tet(S), tet(K), vanA, vanB] coding for resistance to antibiotics conventionally used in clinical practice was determined. The majority of samples were positive for tet(M) (70.0%), tet(K) (83.3%) and blaZ (83.3%). A low percentage of samples were positive for erm(B) (16.7%), erm(C) (26.7%), and aac(6’)‐Ie aph(2″)‐Ia (13.3%), whereas no samples were positive for erm(A), vanA, vanB, tet(O), and mecA. Cluster analysis identified 4 main clusters, allowing a separation of samples on the basis of their country of origin.     

Candida albicans homologue of GGP1/GAS1 gene is functional in Saccharomyces cerevisiae and contains the determinants for glycosylphosphatidylinositol attachment

The GGP1/GAS1/CWH52 gene of Saccharomyces cerevisiae encodes a major exocellular 115 kDa glycoprotein (gp115) anchored to the plasma membrane through a glycosylphosphatidylinositol (GPI). The function of gp115 is still unknown but the analysis of null mutants suggests a possible role in the control of morphogenesis. PHR1 gene isolated from Candida alibicans is homologous to the GGP1 gene. In this report we have analysed the ability of PHR1 to complement a ggp1Δ mutation in S. cerevisiae. The expression of PHR1 controlled by its natural promoter or by the GGP1 promoter has been studied. In both cases we have observed a complete complementation of the mutant phenotype. Moreover, immunological analysis has revealed that PHR1 in budding yeast gives rise to a 75–80 kDa protein anchored to the membrane through a GPI, indicating that the signal for GPI attachment present in the C. albicans gene product is functional in S. cerevisiae.     

Beneficial and Sexually Dimorphic Response to Combined HDAC Inhibitor Valproate and AMPK/SIRT1 Pathway Activator Resveratrol in the Treatment of ALS Mice

Amyotrophic lateral sclerosis (ALS) is a fatal adult-onset neurodegenerative disorder. There is no cure and current treatments fail to slow the progression of the disease. Epigenetic modulation in the acetylation state of NF-kB RelA and the histone 3 (H3) protein, involved in the development of neurodegeneration, is a drugable target for the class-I histone deacetylases (HDAC) inhibitors, entinostat or valproate, and the AMP-activated kinase (AMPK)-sirtuin 1 pathway activator, resveratrol. In this study, we demonstrated that the combination of valproate and resveratrol can restore the normal acetylation state of RelA in the SOD1(G93A) murine model of ALS, in order to obtain the neuroprotective form of NF-kB. We also investigated the sexually dimorphic development of the disease, as well as the sex-sensibility to the treatment administered. We showed that the combined drugs, which rescued AMPK activation, RelA and the histone 3 acetylation state, reduced the motor deficit and the disease pathology associated with motor neuron loss and microglial reactivity, Brain-Derived Neurotrophic Factor (BDNF) and B-cell lymphoma-extra large (Bcl-xL) level decline. Specifically, vehicle-administered males showed earlier onset and slower progression of the disease when compared to females. The treatment, administered at 50 days of life, postponed the time of onset in the male by 22 days, but not in a significant way in females. Nevertheless, in females, the drugs significantly reduced symptom severity of the later phase of the disease and prolonged the mice’s survival. Only minor beneficial effects were produced in the latter stage in males. Overall, this study shows a beneficial and sexually dimorphic response to valproate and resveratrol treatment in ALS mice.     

Macrophage-Mediated Melanoma Reduction after HP-NAP Treatment in a Zebrafish Xenograft Model

The Helicobacter pylori Neutrophil Activating Protein (HP-NAP) is endowed with immunomodulatory properties that make it a potential candidate for anticancer therapeutic applications. By activating cytotoxic Th1 responses, HP-NAP inhibits the growth of bladder cancer and enhances the anti-tumor activity of oncolytic viruses in the treatment of metastatic breast cancer and neuroendocrine tumors. The possibility that HP-NAP exerts its anti-tumor effect also by modulating the activity of innate immune cells has not yet been explored. Taking advantage of the zebrafish model, we examined the therapeutic efficacy of HP-NAP against metastatic human melanoma, limiting the observational window to 9 days post-fertilization, well before the maturation of the adaptive immunity. Human melanoma cells were xenotransplanted into zebrafish embryos and tracked in the presence or absence of HP-NAP. The behavior and phenotype of macrophages and the impact of their drug-induced depletion were analyzed exploiting macrophage-expressed transgenes. HP-NAP administration efficiently inhibited tumor growth and metastasis and this was accompanied by strong recruitment of macrophages with a pro-inflammatory profile at the tumor site. The depletion of macrophages almost completely abrogated the ability of HP-NAP to counteract tumor growth. Our findings highlight the pivotal role of activated macrophages in counteracting melanoma growth and support the notion that HP-NAP might become a new biological therapeutic agent for the treatment of metastatic melanomas.     

Cytoskeletal Protein 4.1G Is Essential for the Primary Ciliogenesis and Osteoblast Differentiation in Bone Formation

The primary cilium is a hair-like immotile organelle with specific membrane receptors, including the receptor of Hedgehog signaling, smoothened. The cilium organized in preosteoblasts promotes differentiation of the cells into osteoblasts (osteoblast differentiation) by mediating Hedgehog signaling to achieve bone formation. Notably, 4.1G is a plasma membrane-associated cytoskeletal protein that plays essential roles in various tissues, including the peripheral nervous system, testis, and retina. However, its function in the bone remains unexplored. In this study, we identified 4.1G expression in the bone. We found that, in the 4.1G-knockout mice, calcium deposits and primary cilium formation were suppressed in the trabecular bone, which is preosteoblast-rich region of the newborn tibia, indicating that 4.1G is a prerequisite for osteoblast differentiation by organizing the primary cilia in preosteoblasts. Next, we found that the primary cilium was elongated in the differentiating mouse preosteoblast cell line MC3T3-E1, whereas the knockdown of 4.1G suppressed its elongation. Moreover, 4.1G-knockdown suppressed the induction of the cilia-mediated Hedgehog signaling and subsequent osteoblast differentiation. These results demonstrate a new regulatory mechanism of 4.1G in bone formation that promotes the primary ciliogenesis in the differentiating preosteoblasts and induction of cilia-mediated osteoblast differentiation, resulting in bone formation at the newborn stage.     

Hybrid Nanoparticles and Composite Hydrogel Systems for Delivery of Peptide Antibiotics

The growing number of drug-resistant pathogenic bacteria poses a global threat to human health. For this reason, the search for ways to enhance the antibacterial activity of existing antibiotics is now an urgent medical task. The aim of this study was to develop novel delivery systems for polymyxins to improve their antimicrobial properties against various infections. For this, hybrid core–shell nanoparticles, consisting of silver core and a poly(glutamic acid) shell capable of polymyxin binding, were developed and carefully investigated. Characterization of the hybrid nanoparticles revealed a hydrodynamic diameter of approximately 100 nm and a negative electrokinetic potential. The nanoparticles demonstrated a lack of cytotoxicity, a low uptake by macrophages, and their own antimicrobial activity. Drug loading and loading efficacy were determined for both polymyxin B and E, and the maximal loaded value with an appropriate size of the delivery systems was 450 µg/mg of nanoparticles. Composite materials based on agarose hydrogel were prepared, containing both the loaded hybrid systems and free antibiotics. The features of polymyxin release from the hybrid nanoparticles and the composite materials were studied, and the mechanisms of release were analyzed using different theoretical models. The antibacterial activity against Pseudomonas aeruginosa was evaluated for both the polymyxin hybrid and the composite delivery systems. All tested samples inhibited bacterial growth. The minimal inhibitory concentrations of the polymyxin B hybrid delivery system demonstrated a synergistic effect when compared with either the antibiotic or the silver nanoparticles alone.     

Impact of Endocrine Disruptors upon Non-Genetic Inheritance

Similar to environmental factors, EDCs (endocrine-disrupting chemicals) can influence gene expression without modifying the DNA sequence. It is commonly accepted that the transgenerational inheritance of parentally acquired traits is conveyed by epigenetic alterations also known as “epimutations”. DNA methylation, acetylation, histone modification, RNA-mediated effects and extracellular vesicle effects are the mechanisms that have been described so far to be responsible for these epimutations. They may lead to the transgenerational inheritance of diverse phenotypes in the progeny when they occur in the germ cells of an affected individual. While EDC-induced health effects have dramatically increased over the past decade, limited effects on sperm epigenetics have been described. However, there has been a gain of interest in this issue in recent years. The gametes (sperm and oocyte) represent targets for EDCs and thus a route for environmentally induced changes over several generations. This review aims at providing an overview of the epigenetic mechanisms that might be implicated in this transgenerational inheritance.