Proteomic studies on lactic acid bacteria: A review

Lactic acid bacteria viability in different refrigerated food matrices: a systematic review and Meta‑analysis

The aim of this systematic review and meta-analysis was to determine which variables affect the viability of lactic acid bacteria (LAB) added to different types of refrigerated foods during the first 28 days. Scopus, ScienceDirect, PubMed and Cochrane Central Register of Reviews databases were searched from 1997 to April 2022. A total of 278 studies, which showed randomized and controlled experiments published in peer reviewed journals, were included. The viability of LAB in different moments during the storage process was synthesized as mean point estimate (MPE) via random-effects meta-analyses and the effect of multiple factors on the LAB´s viability was evaluated by multiple meta-regression. The meta-analysis showed that the decrease in LAB viability will be more abrupt the greater the initial dose. The physical structure of food may influence bacterial viability. Fruit was the type of product that most quickly lost viability. Co-culture of two or more species did not affect viability. Preservation methods had an unfavorable effect and prebiotics had a beneficial effect on bacterial viability. Viability was genus dependent. The data obtained in this study provide an overview of the factors to be taken into account for the design of new foods.

The ameliorating effect of limosilactobacillus fermentum and its supernatant postbiotic on cisplatin-induced chronic kidney disease in an animal model

BACKGROUND

Chronic kidney disease (CKD) is a worldwide public health problem affecting millions of people. Probiotics and postbiotics are associated with valuable compounds with antibacterial, anti-inflammatory, and immunomodulatory effects, preserving renal function in CKD patients. The current study is aimed to evaluate the efficacy of Limosilactobacillus fermentum (L. fermentum) and its postbiotic in an animal model of cisplatin-induced CKD.

METHODS

The animals were divided into four experimental groups (normal mice, CKD mice with no treatment, CKD mice with probiotic treatment, and CKD mice with postbiotic treatment). CKD mice were induced by a single dose of cisplatin 10 mg/kg, intraperitoneally. For 28 days, the cultured probiotic bacteria and its supernatant (postbiotic) were delivered freshly to the related groups through their daily water. Then, blood urea nitrogen (BUN) and creatinine (Cr) of plasma samples as well as glutathione (GSH), lipid peroxidation, reactive oxygen species, and total antioxidant capacity of kidneys were assessed in the experimental mice groups. In addition, histopathological studies were performed on the kidneys.

RESULTS

Application of L. fermentum probiotic, and especially postbiotics, significantly decreased BUN and Cr (P < 0.0001) as well as ROS formation and lipid peroxidation levels (P < 0.0001) along with increased total antioxidant capacity and GSH levels (P < 0.001). The histopathologic images also confirmed their renal protection effect. Interestingly, the postbiotic displayed more effectiveness than the probiotic in some assays. The improvement effect on renal function in the current model is mainly mediated by oxidative stress markers in the renal tissue.

CONCLUSIONS

In conclusion, it was found that the administration of L. fermentum probiotic, and particularly its postbiotic in cisplatin-induced CKD mice, showed promising effects and could successfully improve renal function in the animal model of CKD. Therefore, probiotics and postbiotics are considered as probably promising alternative supplements to be used for CKD.

Physical, Nutritional, and Bioactive Properties of Mandacaru Cladode Flour (Cereus jamacaru DC.): An Unconventional Food Plant from the Semi-Arid Brazilian Northeast

In this study, we evaluated the physical, nutritional, and bioactive properties of mandacaru cladode flour (Cereus jamacaru DC.). The granulometric profile revealed particles with non-uniform geometry, flakiness, a rectangular tendency, and a non-homogeneous surface, with particle sizes ranging from 20 to 60 µm. The flour presented low water activity (0.423), a moisture content of 8.24 g/100 g, high ash (2.82 g/100 g), protein (5.18 g/100 g), and total carbohydrate contents (74.48 g/100 g), and low lipid contents (1.88 g/100 g). Mandacaru flour is an excellent source of insoluble dietary fiber (48.08 g/100 g), calcium (76.33%), magnesium (15.21%), and potassium (5.94%). Notably, ¹H NMR analysis revealed the presence of N-methyltyramine. Using HPLC chromatography, glucose was identified as the predominant sugar (1.33 g/100 g), followed by four organic acids, especially malic acid (9.41 g/100 g) and citric acid (3.96 g/100 g). Eighteen phenolic compounds were detected, with relevant amounts of kaempferol (99.40 mg/100 g), myricetin (72.30 mg/100 g), and resveratrol (17.84 mg/100 g). The total phenolic compounds and flavonoids were 1285.47 mg GAE/100 g and 15.19 mg CE/100 g, respectively. The mean in vitro antioxidant activity values were higher using the FRAP method (249.45 µmol Trolox TEAC/100 g) compared to the ABTS^•+ method (0.39 µmol Trolox TEAC/g). Finally, the ascorbic acid had a content of 35.22 mg/100 g. The results demonstrate the value of mandacaru as a little-explored species and an excellent matrix for the development of flours presenting good nutritional value and bioactive constituents with excellent antioxidant potential.

Lactobacillus plantarum surface-displayed ASFV (p54) with porcine IL-21 generally stimulates protective immune responses in mice

African classical swine fever virus (ASFV) has spread seriously around the world and has dealt with a heavy blow to the pig breeding industry due to the lack of vaccines. In this study, we produced recombinant Lactobacillus plantarum (L. plantarum) expressing an ASFV p54 and porcine IL-21 (pIL-21) fusion protein and evaluated the immune effect of NC8-pSIP409-pgsA'-p54-pIL-21 in a mouse model. First, we verified that the ASFV p54 protein and p54-pIL-21 fusion protein were anchored on the surface of L. plantarum NC8 by flow cytometry, immunofluorescence and Western blotting. Then, the results were verified by flow cytometry, ELISA and MTT assays. Mouse-specific humoral immunity and mucosal and T cell-mediated immune responses were induced by recombinant L. plantarum. The results of feeding mice recombinant L. plantarum showed that the levels of serum IgG and mucosal secreted IgA (SIgA), the number of CD4 and CD8 T cells, and the expression of IFN-γ in CD4 and CD8 T cells increased significantly, and lymphocyte proliferation occurred under stimulation with the ASFV p54 protein. Our data lay a foundation for the development of oral vaccines against ASFV in the future.

The study of the molecular mechanism of Lactobacillus paracasei clumping via divalent metal ions by electrophoretic separation

In this work, the molecular mechanism of Lactobacillus paracasei bio-colloid clumping under divalent metal ions treatment such as zinc, copper and magnesium at constant concentrations was studied. The work involved experimental (electrophoretic - capillary electrophoresis in pseudo-isotachophoresis mode, spectroscopic and spectrometric - FT-IR and MALDI-TOF-MS, microscopic - fluorescent microscopy, and flow cytometry) and theoretical (DFT calculations of model complex systems) characterization. Electrophoretic results have pointed out the formation of aggregates under the Zn²⁺ and Cu²⁺ modification, whereas the use of the Mg²⁺ allowed focusing the zone of L. paracasei biocolloid. According to the FT-IR analysis, the major functional groups involved in the aggregation are deprotonated carboxyl and amide groups derived from the bacterial surface structure. Nature of the divalent metal ions was shown to be one of the key factors influencing the bacterial aggregation process. Proteomic analysis showed that surface modification had a considerable impact on bacteria molecular profiles and protein expression, mainly linked to the activation of carbohydrate and nucleotides metabolism as well with the transcription regulation and membrane transport. Density-functional theory (DFT) calculations of modeled Cu²⁺, Mg²⁺ and Zn²⁺ coordination complexes support the interaction between the divalent metal ions and bacterial proteins. Consequently, the possible mechanism of the aggregation phenomenon was proposed. Therefore, this comprehensive study could be further applied in evaluation of biocolloid aggregation under different types of metal ions.

High-throughput sequencing approach to reveal the bacterial diversity of traditional yak jerky from the Tibetan regions

A high-throughput sequencing approach was used to investigate the bacterial community diversity of traditional Tibetan yak jerky, which was collected from three different regions in Tibet and with different natural drying times. Tibetan yak jerky from different regions had different bacterial communities, which was mainly reflected in the relative abundance levels of unclassified Cyanobacteria, Psychrobacter and Acinetobacter. The unclassified Cyanobacteria was the dominant genus of Qamdo yak jerky, Acinetobacter was the dominant genus of Shigatse yak jerky, and Psychrobacteria was the dominant genus of Nyingchi yak jerky. With increasing natural drying time, the diversity of bacterial communities in yak jerky decreased, and unclassified Cyanobacteria become the dominant genus. Spearman's correlation analysis and canonical correspondence analysis revealed that physicochemical factors (moisture content, water activity, shear force and pH) were significantly correlated with bacterial community. Our results will be beneficial to improve and standardize the safety and quality of traditional Tibetan yak jerky.

Molecular typing tools for identifying and characterizing lactic acid bacteria: a review

Identification and classification of beneficial microbes is of the highest significance in food science and related industries. Conventional phenotypic approaches pose many challenges, and they may misidentify a target, limiting their use. Genotyping tools show comparatively better prospects, and they are widely used for distinguishing microorganisms. The techniques already employed in genotyping of lactic acid bacteria (LAB) are slightly different from one another, and each tool has its own advantages and disadvantages. This review paper compiles the comprehensive details of several fingerprinting tools that have been used for identifying and characterizing LAB at the species, sub-species, and strain levels. Notably, most of these approaches are based on restriction digestion, amplification using polymerase chain reaction, and sequencing. Nowadays, DNA sequencing technologies have made considerable progress in terms of cost, throughput, and methodology. A research journey to develop improved versions of generally applicable and economically viable tools for fingerprinting analysis is ongoing globally.

Updates on understanding of probiotic lactic acid bacteria responses to environmental stresses and highlights on proteomic analyses

Probiotics are defined as live microorganisms that improve the health of the host when administered in adequate quantities. Nonetheless, probiotics encounter extreme environmental conditions during food processing or along the gastrointestinal tract. This review discusses different environmental stresses that affect probiotics during food preparation, storage, and along the alimentary canal, including high temperature, low temperature, low and alkaline pH, oxidative stress, high hydrostatic pressure, osmotic pressure, and starvation. The understanding of how probiotics deal with environmental stress and thrive provides useful information to guide the selection of the strains with enhanced performance in specific situations, in food processing or during gastrointestinal transit. In most cases, multiple biological functions are affected upon exposure of the cell to environmental stress. Sensing of sublethal environmental stress can allow for adaptation processes to occur, which can include alterations in the expression of specific proteins.

Multi-Product Lactic Acid Bacteria Fermentations: A Review

Industrial biotechnology is a continuously expanding field focused on the application of microorganisms to produce chemicals using renewable sources as substrates. Currently, an increasing interest in new versatile processes, able to utilize a variety of substrates to obtain diverse products, can be observed. A robust microbial strain is critical in the creation of such processes. Lactic acid bacteria (LAB) are used to produce a wide variety of chemicals with high commercial interest. Lactic acid (LA) is the most predominant industrial product obtained from LAB fermentations, and its production is forecasted to rise as the result of the increasing demand of polylactic acid. Hence, the creation of new ways to revalorize LA production processes is of high interest and could further enhance its economic value. Therefore, this review explores some co-products of LA fermentations, derived from LAB, with special focus on bacteriocins, lipoteichoic acid, and probiotics. Finally, a multi-product process involving LA and the other compounds of interest is proposed.

Recent systems biology approaches for probiotics use in health aspects: a review

The market of probiotics is growing dynamically for the food and supplements, which provides better health to an individual. Probiotics are used as dietary management for diseases, but it varies between regions and persons. Systems biology can help in resolving the strain specificity of probiotics by studying their genome level organization. In this review, we have compiled facets of systems biology and next-generation omics methods such as metagenomics, proteomics and metabolomics. These tools are crucial for the optimization of the metabolic processes in probiotics and hence, their use for human health. The limitations and challenges associated with the development of probiotics involve their stability and function in different individuals. Systems biology facilitates emerging metabolic engineering approaches to improve probiotics strain for their broader application. This review provides comprehensive and updated knowledge of engineered probiotics as therapeutics and various challenges in the development of engineered probiotics.

Proteomics for understanding pathogenesis, immune modulation and host pathogen interactions in aquaculture

Proteomic analyses techniques are considered strong tools for identifying and quantifying the protein contents in different organisms, organs and secretions. In fish biotechnology, the proteomic analyses have been used for wide range of applications such as identification of immune related proteins during infections and stresses. The proteomic approach has a significant role in understanding pathogen surviving strategies, host defence responses and subsequently, the fish pathogen interactions. Proteomic analyses were employed to highlight the virulence related proteins secreted by the pathogens to invade the fish host's defence barriers and to monitor the kinetics of protein contents of different fish organs in response to infections. The immune related proteins of fish and the virulence related proteins of pathogens are up or down regulated according to their functions in defence or pathogenesis. Therefore, the proteomic analyses are useful in understanding the virulence mechanisms of microorganisms and the fish pathogen interactions thereby supporting the development of new effective therapies. In this review, we focus and summarise the recent proteomic profiling studies exploring pathogen virulence activities and fish immune responses to stressors and infections.

Binding activity to intestinal cells and transient colonization in mice of two Lactobacillus paracasei subsp. paracasei strains with high aggregation potential

Surface properties like hydrophobicity, aggregation ability, adhesion to mucosal surfaces and epithelial cells and transit time are key features for the characterization of probiotic strains. In this study, we used two Lactobacillus paracasei subsp. paracasei strains (BGNJ1-64 and BGSJ2-8) strains which were previously described with very strong aggregation capacity. The aggregation promoting factor (AggLb) expressed in these strains showed high level of binding to collagen and fibronectin, components of extracellular matrix. The working hypothesis was that strains able to aggregate have an advantage to resist in intestinal tract. So, we assessed whether these strains and their derivatives (without aggLb gene) are able to bind or not to intestinal components and we compared the transit time of each strains in mice. In that purpose parental strains (BGNJ1-64 and BGSJ2-8) and their aggregation negative derivatives (BGNJ1-641 and BGSJ2-83) were marked with double antibiotic resistance in order to be tracked in in vivo experiments in mice. Comparative analysis of binding ability of WT and aggregation negative strains to different human intestinal cell lines and mucin revealed no significant difference among them, excluding involvement of AggLb in interaction with surface of intestinal cells and mucin. In vivo experiments showed that surviving and transit time of marked strains in mice did not drastically depend on the presence of the AggLb aggregation factor.

Probiotics: current landscape and future horizons

In recent years there has been a rapid rise in interest for the application of probiotic supplements to act as mediators in health and disease. This appeal is predominantly due to ever-increasing evidence of the interaction of the microbiota and pathophysiological processes of disease within the human host. This narrative review considers the current landscape of the probiotic industry and its research, and discusses current pitfalls in the lack of translation from laboratory science to clinical application. Future considerations into how industry and academia must adapt probiotic research to maximize success are suggested, including more targeted application of probiotic strains dependent on individual capabilities as well as application of multiple advanced analytical technologies to further understand and accelerate microbiome science.

Dual Analysis of Virus-Host Interactions: The Case of Ostreid herpesvirus 1 and the Cupped Oyster Crassostrea gigas

Dual analyses of the interactions between Ostreid herpesvirus 1 (OsHV-1) and the bivalve Crassostrea gigas during infection can unveil events critical to the onset and progression of this viral disease and can provide novel strategies for mitigating and preventing oyster mortality. Among the currently used “omics” technologies, dual transcriptomics (dual RNA-seq) coupled with the analysis of viral DNA in the host tissues has greatly advanced the knowledge of genes and pathways mostly contributing to host defense responses, expression profiles of annotated and unknown OsHV-1 open reading frames (ORFs), and viral genome variability. In addition to dual RNA-seq, proteomics and metabolomics analyses have the potential to add complementary information, needed to understand how a malacoherpesvirus can redirect and exploit the vital processes of its host. This review explores our current knowledge of “omics” technologies in the study of host-pathogen interactions and highlights relevant applications of these fields of expertise to the complex case of C gigas infections by OsHV-1, which currently threaten the mollusk production sector worldwide.

The Intestinal Microbiota of Hermetia illucens Larvae Is Affected by Diet and Shows a Diverse Composition in the Different Midgut Regions

The larva of the black soldier fly (Hermetia illucens) has emerged as an efficient system for the bioconversion of organic waste. Although many research efforts are devoted to the optimization of rearing conditions to increase the yield of the bioconversion process, microbiological aspects related to this insect are still neglected. Here, we describe the microbiota of the midgut of H. illucens larvae, showing the effect of different diets and midgut regions in shaping microbial load and diversity. The bacterial communities residing in the three parts of the midgut, characterized by remarkable changes in luminal pH values, differed in terms of bacterial numbers and microbiota composition. The microbiota of the anterior part of the midgut showed the highest diversity, which gradually decreased along the midgut, whereas bacterial load had an opposite trend, being maximal in the posterior region. The results also showed that the influence of the microbial content of ingested food was limited to the anterior part of the midgut, and that the feeding activity of H. illucens larvae did not significantly affect the microbiota of the substrate. Moreover, a high protein content compared to other macronutrients in the feeding substrate seemed to favor midgut dysbiosis. The overall data indicate the importance of taking into account the presence of different midgut structural and functional domains, as well as the substrate microbiota, in any further study that aims at clarifying microbiological aspects concerning H. illucens larval midgut.IMPORTANCE The demand for food of animal origin is expected to increase by 2050. Since traditional protein sources for monogastric diets are failing to meet the increasing demand for additional feed production, there is an urgent need to find alternative protein sources. The larvae of Hermetia illucens emerge as efficient converters of low-quality biomass into nutritionally valuable proteins. Many studies have been performed to optimize H. illucens mass rearing on a number of organic substrates and to quantitatively and qualitatively maximize the biomass yield. On the contrary, although the insect microbiota can be fundamental for bioconversion processes and its characterization is mandatory also for safety aspects, this topic is largely overlooked. Here, we provide an in-depth study of the microbiota of H. illucens larval midgut, taking into account pivotal aspects, such as the midgut spatial and functional regionalization, as well as microbiota and nutrient composition of the feeding substrate.

Non-isoflavones Diet Incurred Metabolic Modifications Induced by Constipation in Rats via Targeting Gut Microbiota

Isoflavones, presenting in leguminous plants and the normal chow diet, are known to alter intestinal microbiota, yet their deficiency has not been widely studied for its effect on constipation in biochemical state of rats. Our previous study discovered the differences in pharmacokinetic traits of isoflavones from Semen sojae praeparatum fed with normal chow diet (ISO) and non-isoflavones diet (NISO). To gain insight into the key role of intestinal microbiota in constipation and metabolic differences caused by isoflavones deficiency, we observed a significant decrease in fecal pellet numbers, fecal water content, intestinal transit rate together with the serum concentrations of substance P (SP) and vasoactive intestinal peptide (VIP) in NISO group, compared with those in the ISO group. Following 16S rRNA compositional sequencing, results excluded the changes in intestinal microbiota over time and highlighted that a total of 5 phyla and 21 genera changed significantly, among which Firmicutes, Bacteroidetes, Blautia, Prevotella, Lactobacillus and Bifidobacterium were closely related to constipation. In addition, Lactobacillus, produceing β-glucosidase which contribute to biotransform glycosides into aglycons and exert the bioactivities consequently, was decreased after non-isoflavones diet intake. Meanwhile, predicted metagenomics indicated that the pathway of glycan biosynthesis and metabolism was markedly down-regulated after non-isoflavones diet intake. Taken together, the findings suggested that the changes in the dietary components could alter the biochemical state of rats, which may be triggered by the abnormal modifications facilitated by β-glucosidase-producing bacteria. Our study shed a new strategy to explore the relationship among disease phenotypes (D), intestinal microbiota (I), enzymes (E) and traits of metabolism (T) named as "DIET," which can provide a reference for further study of the mechanism in regulation of intestinal bacteria-mediated diet on diseases.

Lactobacillus plantarum CQPC11 Isolated from Sichuan Pickled Cabbages Antagonizes d-galactose-Induced Oxidation and Aging in Mice

Chinese pickled cabbage is a traditional fermented food that contains abundant microbes produced during the process of fermentation. In this work, an in vivo animal study was conducted to investigate the effects of a newly isolated lactic acid bacterium (Lactobacillus plantarum CQPC11, LP-CQPC11) on d-galactose-induced oxidation and aging in mice. Analysis of the serum and tissue samples of these mice using molecular biology approaches showed that LP-CQPC11 suppressed the decrease in thymus, brain, heart, liver, spleen, and kidney indices caused by oxidation and aging. Furthermore, LP-CQPC11 increased the levels of SOD (superoxide dismutase), GSH-Px (glutathione peroxidase), and GSH (glutathione), whereas it reduced the levels of NO (nitric oxide) and MDA (malondialdehyde) in the serum, liver, and spleen of oxidation and aging mouse models. Pathological observation indicated that LP-CQPC11 alleviated the damage caused by oxidation and aging on the liver and spleen of mice. qPCR analysis indicated that LP-CQPC11 effectively upregulated the expression of nNOS (neuronal nitric oxide synthase), eNOS (endothelial nitric oxide synthase), Cu/Zn-SOD (cuprozinc-superoxide dismutase), Mn-SOD (manganese superoxide dismutase), CAT (catalase), HO-1 (heme oxygenase-1), Nrf2 (nuclear factor-erythroid 2 related factor 2), γ-GCS (γ-glutamylcysteine synthetase), and NQO1 (NAD(P)H dehydrogenase [quinone] 1), but downregulated the expression of iNOS (inducible nitric oxide synthase) in the mouse liver and spleen. Western blot analysis showed that LP-CQPC11 effectively upregulated SOD1 (Cu/Zn-SOD), SOD2 (Mn-SOD), CAT, GSH1 (c-glutamylcysteine synthetase), and GSH2 (glutathione synthetase) protein expression in mouse liver and spleen tissues. These findings suggest that LP-CQPC11 can effectively prevent d-galactose-induced oxidation and aging in mice, and the effect is even better than that of the commonly used Lactobacillus delbruechii subsp. bulgaricus (LDSB) and vitamin C in the industry. Thus, LP-CQPC11 may be potentially employed as a probiotic strain.