Antioxidant capacity and identification of radical scavenging peptides from Crema de Chiapas, Fresco and Cocido cheeses

Bioactive peptides may positively impact bodily functions. One of these are the antioxidant peptides which are well documented for a wide variety of food matrices, mostly from plant sources. Nevertheless, information of antioxidant milk-derived peptides is still a little-known field. The present study was aimed to evaluating the antioxidant capacity (AC) in vitro of water soluble extracts < 3 kDa (WSE) from three artisanal Mexican cheeses: Crema de Chiapas (CrC), Fresco (FC) and Cocido (CC). This study was carried out for cheeses of different days of storage (0, 5, 10, 15, and 20) at 4 °C. AC was assayed to the respective WSE by 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) diamoniun salt (ABTS) and oxygen radical absorbance capacity (ORAC) methods and those WSE that showed the most antioxidant capacity from each cheese were analyzed by using RP-HPLC/MS to identify and characterize the novel specific peptides. All the WSE analyzed show antioxidant capacity, especially those from CrC and CC which display the highest AC at 15 days of storage. Regarding to WSE from FC, the AC was constant during storage. Identified structures reveal that these novel peptides possess high content of specific amino acids, mainly proline, valine, leucine and phenylalanine, of which it has already been shown antioxidant properties. This study demonstrate that these artisanal Mexican cheeses are sources of potential antioxidant peptides.

Are Bacteriocins a Feasible Solution for Current Diverse Global Problems?

The development of effective technologies to cope with persistent and progressive global problems in the areas of human health and sustainable development has become an imperative worldwide challenge. The search for natural alternatives has led to the discovery of bacteriocins, which are potent protein antimicrobial compounds produced by most bacteria. The relevance of these molecules is evidenced by the more than 4,500 papers published in the last decade in Scopus index journals highlighting their versatility and potential to impact various aspects of daily life, including the food industry, medicine, and agriculture. Bacteriocins have demonstrated antibacterial, antifungal, antiviral, and anticancer activity, and they also act as microbiota regulators and plant growth promoters. This mini-review aims to provide insights into the current state and emerging roles of bacteriocins, as well as their potential and limitations as feasible solutions against current diverse global problems.

In Silico Prediction and In Vitro Assessment of Multifunctional Properties of Postbiotics Obtained From Two Probiotic Bacteria

In this study, a global metabolite profile using Raman spectroscopy analysis was obtained in order to predict, by an in silico prediction of activity spectra for substance approach, the bioactivities of the intracellular content (IC) and cell wall (CW) fractions obtained from Lactobacillus casei CRL 431 and Bacillus coagulans GBI-30 strains. Additionally, multifunctional in vitro bioactivity of IC and CW fractions was also assessed. The metabolite profile revealed a variety of compounds (fatty acids, amino acids, coenzyme, protein, amino sugars), with significant probable activities (Pa > 0.7) as immune-stimulant, anti-inflammatory, neuroprotective, antiproliferative, immunomodulator, and antineoplastic, among others. Moreover, in vitro assays exhibited that both IC and CW fractions presented angiotensin-converting enzyme-inhibitory (> 90%), chelating (> 79%), and antioxidant (ca. 22-57 cellular antioxidant activity units) activities. Our findings based on in silico and in vitro analyses suggest that L. casei CRL 431 and B. coagulans GBI-30 strains appear to be promising sources of postbiotics and may impart health benefits by their multifunctional properties.

High-throughput transcriptome sequencing and comparative analysis of Escherichia coli and Schizosaccharomyces pombe in respiratory and fermentative growth

In spite of increased complexity in eukaryotes compared to prokaryotes, several basic metabolic and regulatory processes are conserved. Here we explored analogies in the eubacteria Escherichia coli and the unicellular fission yeast Schizosaccharomyces pombe transcriptomes under two carbon sources: 2% glucose; or a mix of 2% glycerol and 0.2% sodium acetate using the same growth media and growth phase. Overall, twelve RNA-seq libraries were constructed. A total of 593 and 860 genes were detected as differentially expressed for E. coli and S. pombe, respectively, with a log2 of the Fold Change ≥ 1 and False Discovery Rate ≤ 0.05. In aerobic glycolysis, most of the expressed genes were associated with cell proliferation in both organisms, including amino acid metabolism and glycolysis. In contrast in glycerol/acetate condition, genes related to flagellar assembly and membrane proteins were differentially expressed such as the general transcription factors fliA, flhD, flhC, and flagellum assembly genes were detected in E. coli, whereas in S. pombe genes for hexose transporters, integral membrane proteins, galactose metabolism, and ncRNAs related to cellular stress were overexpressed. In general, our study shows that a conserved "foraging behavior" response is observed in these eukaryotic and eubacterial organisms in gluconeogenic carbon sources.

Modulatory Effect of the Intracellular Content of Lactobacillus casei CRL 431 Against the Aflatoxin B1-Induced Oxidative Stress in Rats

It has been recognized that lactic acid bacteria exhibit antioxidant properties, which have been mainly endorsed to the intact viable bacteria. However, recent studies have shown that intracellular content (IC) may also be good sources of antioxidative metabolites, which may potentially contribute to oxidative homeostasis in vivo. Hence, the modulatory effect of the intracellular content of Lactobacillus casei CRL 431 (IC431) on aflatoxin B₁ (AFB₁)-induced oxidative stress in rats was evaluated on the basis of its influence on hepatic lipid peroxidation (LPO), antioxidant status-antioxidant capacity (TAC), catalase (CAT), and glutathione peroxidase (GPx) activities; and on the oxidative stress index (OSi). Results demonstrated that CAT and GPx activities, and TAC, determined in plasma samples, were significantly (P < 0.05) higher in rats treated with AFB₁ plus IC431 (3.98 μM/min/mg protein, 1.88 μM/min/mg protein, and 238.7 μM Trolox equivalent, respectively) than AFB₁-treated rats (3.47 μM/min/mg protein, 1.46 μM/min/mg protein, and 179.7 μM Trolox equivalent, respectively). Furthermore, plasma and liver tissue samples from rats treated with AFB₁ plus IC431 showed significantly (P < 0.05) lower LPO values (52 and 51%, respectively) and OSi (59 and 51%, respectively) than AFB₁-treated rats. Hence, our results proved that the intracellular content of Lact. casei CRL 431 contains metabolites that are capable to modulate the antioxidant defense systems in living organism, which may help to ameliorate the damage associated to AFB₁-induced oxidative stress.

The Polycyclic Aromatic Hydrocarbon (PAH) degradation activities and genome analysis of a novel strain Stenotrophomonas sp. Pemsol isolated from Mexico

Background

Stenotrophomonas are ubiquitous gram-negative bacteria, which can survive in a wide range of environments. They can use many substances for their growth and are known to be intrinsically resistant to many antimicrobial agents. They have been tested for biotechnological applications, bioremediation, and production of antimicrobial agents.

Method

Stenotrophomonas sp. Pemsol was isolated from a crude oil contaminated soil. The capability of this isolate to tolerate and degrade polycyclic aromatic hydrocarbons (PAH) such as anthraquinone, biphenyl, naphthalene, phenanthrene, phenanthridine, and xylene was evaluated in Bushnell Hass medium containing PAHs as the sole carbon sources. The metabolites formed after 30-day degradation of naphthalene by Pemsol were analyzed using Fourier Transform Infra-red Spectroscopic (FTIR), Ultra-Performance Liquid Chromatography-Mass Spectrometry (UPLC-MS) and Gas Chromatography-Mass Spectrometry (GC-MS). The genome of Pemsol was also sequenced and analyzed.

Results

Anthraquinone, biphenyl, naphthalene, phenanthrene, and phenanthridine except xylene can be used as sole carbon sources for Pemsol’s growth in Bushnell Hass medium. The degradation of naphthalene at a concentration of 1 mg/mL within 30 days was tested. A newly formed catechol peak and the disappearance of naphthalene peak detected on the UPLC-MS, and GC-MS analyses spectra respectively confirmed the complete degradation of naphthalene. Pemsol does not produce biosurfactant and neither bio-emulsify PAHs. The whole genome was sequenced and assembled into one scaffold with a length of 4,373,402 bp. A total of 145 genes involved in the degradation of PAHs were found in its genome, some of which are Pemsol-specific as compared with other 11 Stenotrophomonas genomes. Most specific genes are located on the genomic islands. Stenotrophomonas sp. Pemsol’s possession of few genes that are associated with bio-emulsification gives the genetic basis for its inability to bio-emulsify PAH. A possible degradation pathway for naphthalene in Pemsol was proposed following the analysis of Pemsol’s genome. ANI and GGDH analysis indicated that Pemsol is likely a new species of Stenotrophomonas. It is the first report on a complete genome sequence analysis of a PAH-degrading Stenotrophomonas. Stenotrophomonas sp. Pemsol possesses features that make it a good bacterium for genetic engineering and will be an excellent tool for the remediation of crude oil or PAH-contaminated soil.

Potential role of natural bioactive peptides for development of cosmeceutical skin products

In recent years, consumers' demand for cosmeceutical products with protective and therapeutic functions derived from natural sources have caused this industry to search for alternative active ingredients. Bioactive peptides have a wide spectrum of bioactivities, which make them ideal candidates for development of these cosmeceutical products. In vitro studies have demonstrated that bioactive peptides (obtained as extracts, hydrolysates, and/or individual peptides) exhibit biological properties including antioxidant, antimicrobial, and anti-inflammatory activities, in addition to their properties of inhibiting aging-related enzymes such as elastase, collagenase, tyrosinase and hyaluronidase. Some studies report multifunctional bioactive peptides that can simultaneously affect, beneficially, multiple physiological pathways in the skin. Moreover, in vivo studies have revealed that topical application or consumption of bioactive peptides possess remarkable skin protection. These properties suggest that bioactive peptides may contribute in the improvement of skin health by providing specific physiological functions, even though the mechanisms underlying the protective effect have not been completely elucidated. This review provides an overview of in vitro, in silico and in vivo properties of bioactive peptides with potential use as functional ingredients in the cosmeceutical field. It also describes the possible mechanisms involved as well as opportunities and challenges associated with their application.

A Review on Viral Metagenomics in Extreme Environments

Viruses are the most abundant biological entities in the biosphere, and have the ability to infect Bacteria, Archaea, and Eukaryotes. The virome is estimated to be at least ten times more abundant than the microbiome with 10⁷ viruses per milliliter and 10⁹ viral particles per gram in marine waters and sediments or soils, respectively. Viruses represent a largely unexplored genetic diversity, having an important role in the genomic plasticity of their hosts. Moreover, they also play a significant role in the dynamics of microbial populations. In recent years, metagenomic approaches have gained increasing popularity in the study of environmental viromes, offering the possibility of extending our knowledge related to both virus diversity and their functional characterization. Extreme environments represent an interesting source of both microbiota and their virome due to their particular physicochemical conditions, such as very high or very low temperatures and >1 atm hydrostatic pressures, among others. Despite the fact that some progress has been made in our understanding of the ecology of the microbiota in these habitats, few metagenomic studies have described the viromes present in extreme ecosystems. Thus, limited advances have been made in our understanding of the virus community structure in extremophilic ecosystems, as well as in their biotechnological potential. In this review, we critically analyze recent progress in metagenomic based approaches to explore the viromes in extreme environments and we discuss the potential for new discoveries, as well as methodological challenges and perspectives.

Screening of Lactobacillus strains for their ability to produce conjugated linoleic acid in milk and to adhere to the intestinal tract

Conjugated linoleic acid (CLA) has been shown to provide beneficial effects on health; however, the amount consumed in food is far from that required for the desired effects. Thus, increasing the CLA content in dairy foods through milk fermentation with specific lactic acid bacteria (LAB) offers an interesting alternative. Moreover, some LAB may be able to adhere to the intestinal mucosa and produce CLA through endogenous synthesis. Therefore, the objective of this study was to screen LAB isolates for their ability to produce CLA in skim milk and in simulated gastrointestinal conditions. Additionally, the ability of selected CLA-producing LAB to adhere to the intestinal mucosa in a murine model was assessed. Results showed that of 13 strains of Lactobacillus tested, only 4 were able to produce CLA in skim milk supplemented with linoleic acid (13.44 ± 0.78 to 50.9 ± 0.26 µg/mL). Furthermore, these 4 Lactobacillus strains were able to survive and produce CLA in simulated gastrointestinal conditions and to adhere to the intestinal mucosa of Wistar rats after 7 d of oral inoculation with fluorescently labeled bacteria. Accordingly, these 4 Lactobacillus strains may be used to manufacture fermented dairy foods to increase CLA content, and consumption of these fermented milks may result in CLA produced endogenously by these LAB.

Antihypertensive and hypolipidemic effect of milk fermented by specific Lactococcus lactis strains

The antihypertensive and hypolipidemic effects of milk fermented by specific Lactococcus lactis strains in spontaneously hypertensive rats (SHR) were investigated. The SHR were fed ad libitum milk fermented by Lc. lactis NRRL B-50571, Lc. lactis NRRL B-50572, Captopril (40mg/kg of body weight, Sigma-Aldrich Co., St. Louis, MO) or purified water for 4 wk. Results suggested that Lc. lactis fermented milks presented a significant blood pressure-lowering effect. No significant difference was noted among milk fermented by Lc. lactis NRRL B-50571 and Captopril by the second and third week of treatment. Additionally, milk fermented by Lc. lactis strains modified SHR lipid profiles. Milk fermented by Lc. lactis NRRL B-50571 and B-50572 were able to reduce plasma low-density lipoprotein cholesterol and triglyceride contents. Thus, milk fermented by Lc. lactis strains may be a coadjuvant in the reduction of hypertension and hyperlipidemia and may be used as a functional food for better cardiovascular health.

Diminished redundancy of outer membrane factor proteins in rhizobiales: a nodT homolog is essential for free-living Rhizobium etli

Rhizobium etli is a gram-negative soil bacterium that induces nitrogen-fixing nodules on common bean roots (Phaseolus vulgaris). R. etli encodes two genes homologous to nodT of Rhizobium leguminosarum. nodTch is chromosomal and forms an operon with new genes resembling a multi-drug efflux pump of the resistance-nodulation-cell division (RND) family. nodTch is the last gene of this operon and can also be independently transcribed; the gene product is located in the bacterial outer membrane. Cell survival requires nodTch under all conditions tested. A second nodT gene, nodTpc, is encoded by plasmid c; it is constitutively transcribed but does not complement the essential function encoded by nodTch. NodT proteins belong to the outer membrane efflux proteins of the TolC superfamily. The number of duplications in the tolC gene family positively correlates with genome size in gram-negative bacteria. Nonetheless, some alpha-proteobacteria, including R. etli, encode fewer outer membrane factor exporters than expected suggesting further roles in addition to detoxification.

[Genetic diversity of 3 DNA probes in the DNA fingerprinting of a Mexican population]

Each individual may be identified by characterizing its genetic material by DNA fingerprinting technology. Its application in Mexico demands a knowledge of the allelic and genotypic diversity of the DNA markers and the probability that two individuals may have the same fingerprint. In the present study the allelic and genotypic diversities of the loci D12S11 (MS43A), D7S22 (g3) and D1S7 (MS1) were determined in 100 Mexican students of the military school of medicine (Escuela Médico Militar de México). The mean allelic frequency of the loci MS43A, g3, and MS1 was 0.01, 0.008 and 0.006, respectively. The heterozygosity of MS43A and g3 was 98 and 99% for MS1. The probability that two individuals might have the same genetic pattern was 2.0 x 10(-4), 1.3 x 10(-4) and 7.2 x 10(-5) for the loci MS43A, g3 and MS1, respectively, and as low as 1.9 x 10(-12) for the three taken together. These data indicate that the genetic diversity of these DNA fingerprinting markers in the Mexican population is high enough to warrant its use in paternity testing and in the identification of individuals in forensic medicine.