Streptococcus Lutetiensis Research Articles

Enhancement of Active Substances in Astragali Radix Broth with Lactic Acid Bacteria Fermentation and the Promotion Role of Chlorella Growth Factor

Astragali Radix, a traditional Chinese herbal medicine widely used for its medicinal properties, is known to be rich in active components that possess various pharmacological effects. However, the effectiveness of microbial fermentation in enhancing the content of these active substances remains unclear. In this study, a microflora of lactic acid bacteria was used to ferment Astragali Radix, and the promoting effect of Chlorella Growth Factor (CGF) on the fermentation process was investigated so as to clarify the changes in major active compound content in the fermented Astragali Radix broth. Non-targeted metabolomic analysis based on ultra-high-performance liquid chromatography–mass spectrometry was conducted to analyze the differences in metabolites before and after fermentation. The results showed that the total polysaccharide, total flavonoid, and total saponin content in the fermented Astragali Radix broth increased by up to 51.42%, 97.76%, and 72.81% under the optimized conditions, respectively. Streptococcus lutetiensis was the dominant bacterial species during the fermentation process. There were significant differences in metabolites in the fermentation broth before and after fermentation, among which amino acids (such as L-Aspartyl-L-Phenylalanine, etc.) and saponin compounds (such as Cloversaponin I, Goyasaponin I, etc.) were the main upregulated metabolites, which can enhance the physiological functions of Astragali Radix fermentation broth. The CGF exhibited the ability to promote the increase of active substance content in the fermented Astragali Radix broth.

Exploring the Effects of an Alfalfa Leaf-Derived Adsorbent on Microbial Community, Ileal Morphology, Barrier Function, and Immunity in Turkey Poults during Chronic Aflatoxin B1 Exposure.

This article follows-up on our recently published work, which evaluated the impact of the addition of an alfalfa leaf-derived adsorbent in the aflatoxin B1 (AFB1)-contaminated diet in regard to the production parameters, blood cell count, serum biochemistry, liver enzymes, and liver histology of turkey poults. This paper presents complementary results on microbial community, ileal morphology, barrier function, and immunity. For this purpose, 350 1-day-old female turkey poults were randomly distributed into five groups: (1) Control, AFB1-free diet; (2) AF, AFB1-contaminated diet at 250 ng/g; (3) alfalfa, AFB1-free diet + 0.5% (w/w) adsorbent; (4) alfalfa + AF, AFB1-contaminated diet at 250 ng/g + 0.5% (w/w) adsorbent; and (5) YCW + AF, AFB1-contaminated diet at 250 ng/g + 0.5% (w/w) commercial yeast cell wall-based adsorbent (reference group). In general, in the AF group, the growth of opportunistic pathogens was promoted, which lead to gut dysbacteriosis, mainly influenced by Streptococcus lutetiensis. Conversely, a significant increase in beneficial bacteria (Faecalibacterium and Coprococcus catus) was promoted by the addition of the plant-based adsorbent. Moreover, the AF group had the lowest villus height and a compromised barrier function, as evidenced by a significant (p < 0.05) increase in fluorescein isothiocyanate dextran (FITC-d), but these negative effects were almost reversed by the addition of the alfalfa adsorbent. Furthermore, the AF + YCW and alfalfa + AF groups exhibited a significant increase in the cutaneous basophil hypersensitivity response compared to the rest of the experimental groups. Taken together, these results pointed out that the alfalfa counteracts the adverse effects of AFB1 in poults, facilitating the colonization of beneficial bacteria and improving the barrier function of the turkey poults.

Streptococcus lutetiensis e Streptococcus equinus como potenciais patógenos emergentes da mastite bovina

ABSTRACT: The current study characterizes the genetic distribution of virulence and antimicrobial resistance of Streptococcus lutetiensis and Streptococcus equinus isolated from cows with clinical mastitis using whole genome sequencing (WGS). Although they are not the protagonist species within the genus Streptococcus, recent studies have isolated these species associated with bovine mastitis. In addition, these species are reported and isolated from humans and other animals. A total of four strains of S. lutetiensis and one of S. equinus were isolated from five cows with identified cases of clinical mastitis at a dairy farm near Ithaca, New York. Nineteen genes associated with antimicrobial resistance and 20 genes associated with virulence were identified in the analyzed strains. All strains presented genes associated with resistance: alr, ddl, gdpD, kasA, murA, lsa(E), msr(D), mef(A), gidB, and LiaF. Resistance genes associated with several different classes of antibiotics have also been reported. Sixteen virulence-associated genes were identified in all strains. Based on our findings, we conclude that the studied species have the potential to cause mastitis in cattle, and further studies are important to elucidate their role.

Biodiversity and Safety: Cohabitation Experimentation in Undefined Starter Cultures for Traditional Dairy Products

Natural starter cultures, characterised by undefined microbiota, can contribute to the technological process, giving peculiar characteristics to artisanal fermented foods. Several species have a long history of safe use and have obtained Qualified Presumption of Safety (QPS) status from the European Food Safety Authority (EFSA), whereas others (non-QPS) could represent a potential risk for consumers’ health and must undergo a safety assessment. In this work, the biodiversity, at species and strain level, by pulsed-field gel electrophoresis (PFGE) and (GTG)5 rep-PCR, of an undefined natural starter culture, in frozen and lyophilized form, obtained from ewe’s raw milk avoiding thermal treatment or microbial selection, was investigated. The culture was constituted by different biotypes of Enterococcus durans, Enterococcus faecium, Enterococcus faecalis, and Lacticaseibacillus paracasei. Streptococcus oralis and Streptococcus salivarius were also found, over species belonging to the Streptococcus bovis–Streptococcus equinus complex (SBSEC), like Streptococcus gallolyticus subsp. macedonicus, Streptococcus lutetiensis, and Streptococcus equinus. Molecular investigation on virulence and antibiotic resistance genes, as well as minimum inhibitory concentration (MIC) determination, revealed that all the non-QPS strains can be considered safe in the perspective of using this culture for cheesemaking. The obtainment of a natural culture directly from ewe’s raw milk bypassing thermal treatment and selection of pro-technological bacteria can be advantageous in terms of biodiversity preservation, but non-QPS microorganisms can be included in the natural starter and also in cheeses, especially in traditional ones obtained from fermenting raw milk. Following EFSA guidelines, artisanal factories should not be allowed to produce starter cultures by themselves from raw milk, running the risk of including some non-QPS species in their culture, and only selected starters could be used for cheesemaking. A revision of the criteria of QPS guidelines should be necessary.

Antilisterial activity of raw sheep milk from two native Epirus breeds: Culture-dependent identification, bacteriocin gene detection and primary safety evaluation of the antagonistic LAB biota

Raw milk from native small ruminant breeds in Epirus, Greece, is a valuable natural source of autochthonous lactic acid bacteria (LAB) strains with superior biotechnological properties. In this study, two bulk milks (RM1, RM2) from two local sheep yards, intended for traditional Kefalotyri cheese production, were preselected for bacteriocin-like antilisterial activity by in vitro tests. Their antagonistic LAB biota was quantified followed by polyphasic (16S rRNA gene sequencing; IGS for Enterococcus; a multiplex-PCR for Leuconostoc) identification of 42 LAB (RM1/18; RM2/24) isolates further evaluated for bacteriocin encoding genes and primary safety traits. Representative isolates of the numerically dominant mesophilic LAB were Leuconostoc mesenteroides (10) in both RMs, Streptococcus parauberis (7) in RM2, and Lactococcus lactis (1) in RM1; the subdominant thermophilic LAB isolates were Enterococcus durans (8), E. faecium (6), E. faecalis (3), E. hirae (1), E. hermanniensis (1), Streptococcus lutetiensis (2), S. equinus (1) and S. gallolyticus (1). Based on their rpoB, araA, dsr and sorA profiles, six Ln. mesenteroides strains (8 isolates) were atypical lying between the subspecies mesenteroides and dextranicum, whereas two strains profiled with Ln. mesenteroides subsp. jonggajibkimchii that is first-time reported in Greek dairy food. Two RM1 E. faecium strain biotypes (3 isolates) showed strong, enterocin-mediated antilisterial activity due to entA/entB/entP possession. One E. durans from RM1 possessed entA and entP, while additional nine RM2 isolates of the E. faecium/durans group processed entA or entP singly. All showed direct (cell-associated) antilisterial activity only, as also both S. lutetiensis strains from RM2 did strongly. Desirably, no LAB isolate was β-hemolyrtic, or cytolysin-positive, or possessed vanA, vanB for vancomycin resistance, or agg, espA, hyl, and IS16 virulence genes. However, all three E. faecalis from RM2 possessed gelE and/or ace virulence genes. In conclusion, all Ln. mesenteroides strains, the two safe, enterocin A-B-P-producing E. faecium strains, and the two antilisterial S. lutetiensis strains should be validated further as potential costarter or adjunct cultures in Kefalotyri cheese. The prevalence of α-hemolytic pyogenic streptococci in raw milk, mainly S. parauberis in RM2, requires consideration in respect to subclinical mastitis in sheep and the farm hygiene overall.

Extraction of Heat-Stabilised Defatted Rice Bran Protein by Solid-State Fermentation Using Heterofermentative Microbes from Traditional Asian Starters.

Heat-stabilised defatted rice bran (HSDRB) is a primary by-product of rice bran oil extraction industry and a nutritious source of protein. However, despite the unique nutritional profile of rice bran protein, the protein-rich by-product, HSDRB is underutilised as a low-value animal feed. Research on protein extraction from HSDRB by enzymatic hydrolysis has attracted the attention of numerous scientists. However, a cost-effective extraction method is required to mitigate the high costs associated with the use of enzymes. Therefore, we have presented an alternative economical and natural approach for protein extraction from HSDRB by solid-state fermentation (SSF) with heterofermentative microbes. SSF of HSDRB with two types of traditional Asian fermentation starters, namely loog-pang and koji, were evaluated for enzyme production and their efficacy in extracting proteins from HSDRB. For this purpose, HSDRB fermentation was carried out for 0, 12, 24, 48, 72 and 96 h followed by 24-hour hydrolysis to evaluate the extracted rice bran protein. In addition, microbiome diversity in the fermentation starters was also determined by metagenomic sequencing of 16S rRNA and internal transcribed spacer to identify bacteria and fungi, respectively. The microbial community in the fermentation starters showed the dominance of lactic acid bacteria (LAB) such as Bacillus subtilis in loog-pang and Streptococcus lutetiensis, Bacillus pumilus, Lactococcus cremoris, Lactococcus garvieae and Pediococcus pentosaceus in koji, while yeast species Saccharomycopsis fibuligera and Saccharomyces cerevisiae dominated the fungal diversity in loog-pang and koji starters, respectively. The results suggest that loog-pang and koji can produce cellulase, neutral and acid proteases during fermentation. Despite the discrepancy in their microbial diversity and the enzyme activity during SSF, both starters could effectively increase protein extraction from HSDRB. A positive relationship between the SSF duration and extracted protein was observed. During SSF with loog-pang and koji after 72 h followed by 24-hour hydrolysis, 65.66 and 66.67 % protein was extracted from HSDRB, respectively. The amino acid analysis of the protein hydrolysate produced by the non-fermented and fermented methods showed no difference and had an abundance of glutamic and aspartic acids, leucine, arginine, alanine and glycine amino acids, which accounted for approx. 58 % of the total amino acids. Loog-pang and koji (traditional Thai and Japanese fermentation starters, respectively) were found to be effective in extracting proteins from HSDRB by SSF although they are inexpensive microbial enzyme sources. Future research aimed at scaling up HSDRB protein extraction for usage in industrial applications can draw on our results.

Analysis of nasal microbial characteristics in patients with allergic rhinitis and non-allergic rhinitis

Objective: To investigate the characteristics of nasal flora and the pathogenic role of differential microbiome in patients with allergic rhinitis (AR) and non-allergic rhinitis (nAR). Methods: Thirty-five patients with AR who attended the rhinology outpatient clinic of the Second Hospital of Harbin Medical University from February to July 2022 were selected. A total of 35 nAR patients were selected as the test group, and 20 cases of healthy people with physical examination at the same period were selected as the control group, including 39 males and 51 females, aged 8 to 55 years. 16SrDNA High-throughput sequencing was used to analyze the relative abundance from nasal flora in the three groups of subjects. Alpha diversity index analysis was conducted with R software, and differences between groups were analyzed with LEfSe, Metastats, and t tests. At the same time, the role of microbiome and its relationship with environmental factors were analyzed with R software. Results: There was a significant difference in the bacterial composition of the samples from the three groups, with the relative abundance of Staphylococcus aureus (P=0.032) and Corynebacterium proinquum (P=0.032) within the AR group being significantly higher than that of the nAR group, and that of Lactobacillus murinus, Lactobacillus kunkeei, and Alcaligenes faecalis (P value was 0.016, 0.005, and 0.001, respectively) being significantly lower than that of the nAR group. The relative abundance of Ackermannia muciniphila within the nAR group was higher than that of the control group (P=0.009). Correlation analysis of environmental factors showed a negative correlation between Lactobacillus kunkeei and IgE (P=0.044), and a positive correlation between Lactobacillus murinus and age (P=0.019). AR and nAR random forest prediction models were constructed for the five genera, respectively, and the area under the curve (AUC) of the models of Streptococcus-SP-FF10, Pseudoalteromonas luteoviolacea, Pseudomonas parafulva, Acinetobacter ursingii, and Azotobacter chroococcum in the AR group was 100% (95%CI: 100% to 100%). The AUC for the Pseudomonas parafulva, Azotobacter chroococcum, Closoridium baratii, Turicibacter-SP-H121, and Streptococcus lutetiensis models in the nAR group was 98.4% (95%CI: 94.9% to 100%). Conclusions: The distribution of nasal flora in AR patients, nAR patients and healthy subjects is significantly different, and the changes of bacterial flora abundance are significantly related to the occurrence of AR and nAR. Combined detection of microbiota has the potential to diagnose AR and nAR patients.

Culturable Diversity and Biological Properties of Bacterial Endophytes Associated with the Medicinal Plants of Vernonia anthelmintica (L.) Willd

As one of the important traditional medicinal plants listed in the Chinese pharmacopoeia, Vernonia anthelmintica (L.) Willd has been shown to possess various biological activities. In this study, we characterized culturable endophytic bacteria associated with the medicinal plant V. anthelmintica collected from Hotan within the Xinjiang autonomous region of China. Bacterial endophytes were identified via 16S rRNA gene sequence analysis and compared to similar sequences from the GenBank. Isolated strains exhibited 99.08–100% similarity to Bacillus haynesii XJB-5, Bacillus proteolyticus XJB-16, Bacillus halotolerans XJB-35, Bacillus safensis XJB-71, Pseudomonas punonensis XJB-7, Lysinibacillus fusiformis XJB-17, Streptococcus lutetiensis XJB-66, Leclercia adecarboxylata XJB-12, Paenibacillus alvei XJB-14, and Pantoea agglomerans XJB-62. The ethyl acetate extracts of the bacterial endophytes demonstrated various pharmacological properties, such as antimicrobial, cytotoxic, antidiabetic, and antioxidant activity, according to a melanin content assay and have shown tyrosinase activity in murine B16 cells. A crude extract of B. halotolerans XJB-35 displayed more powerful biological activities than other bacterial endophytes; therefore, this strain was studied further in order to select the optimized parameters for enhancing the synthesis of bioactive compounds. The optimal culture medium was found to be nutrient broth (NB) medium, using peptone as its carbon source and yeast extract as its nitrogen source. A 24 h incubation time produced the optimal conditions for the maximum growth of B. halotolerans XJB-35 and the production of bioactive compounds. Moreover, we investigated the volatile chemical component of the dichloromethane fraction using GC-MS analysis. Our findings provide valuable information regarding the synthesize of bioactive natural products by B. halotolerans XJB-35 for use by the medicinal and pharmaceutical industries.

Direct utilization and conversion of raw starch to exopolysaccharides by a newly isolated amylolytic Streptococcus sp.

A newly isolated culture is identified as Streptococcus lutetiensis with significant starch saccharifying activity. Along with considerable amylolytic property (∼ 2.71U/mL), the culture exhibited significant production of exopolysaccharide (EPS) in starch medium. Interestingly, the glycosyl transferase activity which is essential in the biosynthesis of polysaccharide is also detected in the culture and after screening and process optimization, a maximum EPS titre of 19.92±0.5g/L was obtained from cassava starch. The crude EPS, after purification and characterization (monosaccharide analysis, FT-IR, TGA, GPC NMR, and SEM) was found to be of dextran nature with a Mw of 1275.36kDa. Dextran type exopolysaccharide are synthesized by dextransucrase enzyme by the transfer of glucosyl residues from sucrose to dextran polymer. Interestingly, the glycosyl transferase enzyme activity which is essential in the biosynthesis of EPS is also detected in the culture. The particle size (447.8 dnm) and the zeta potential (-33.4) analysis of the purified EPS showed that the EPS produced is a stable molecule and has a random coil confirmation when exposed to alkaline condition with shear thinning property. One step conversion of sustainable low-cost starchy raw materials without adding external enzymes for hydrolysis, improved the economic viability of EPS production.

Tetracycline resistance potential of heterotrophic bacteria isolated from freshwater fin-fish aquaculture system

This study investigated the tetracycline resistance potential of heterotrophic bacteria isolated from twenty-four freshwater fin-fish culture ponds in Andhra Pradesh, India. A total of 261 tetracycline resistant bacteria (tetR) were recovered from pond water, pond sediment, fish gills, fish intestine, and fish feed. Bacteria with high tetracycline resistance (tetHR) (n=30) that were resistant to tetracycline concentrations above 128 μg mL-1 were predominantly Lactococcus garvieae followed by Enterobacter spp., Lactococcus lactis, Enterobacter hormaechei, Staphylococcus arlettae, Streptococcus lutetiensis, Staphylococcus spp., Brevundimonas faecalis, Exiguobacterium profundum, Lysinibacillus spp., Stutzerimonas stutzeri, Enterobacter cloacae, and Lactococcus taiwanensis. Resistance to 1024μg mL-1 of tetracycline was observed in L. garvieae, S. arlettae, Enterobacter spp., B. faecalis. Tet(A) (67%) was the predominant resistance gene in tetHR followed by tet(L), tet(S), tet(K), and tet(M). At similar concentrations of exposure, tetracycline procured at the farm level (69.5% potency) exhibited lower inhibition against tetHR bacteria compared to pure tetracycline (99% potency). The tetHR bacteria showed higher cross-resistance to furazolidone (100%) followed by co-trimoxazole (47.5%) and enrofloxacin (11%). The maximum threshold of tetracycline resistance at 1024μg mL-1 was observed in S. arlettae, Enterobacter spp., B. faecalis, and L. garvieae and tet(A) was the major determinant found in this study.

Abstract PR004: Older adult-specific microbes correlate with treatment response and markers of T-cell senescence in NSCLC

Abstract The gut microbiome changes with age and affects many aspects of human health, including response to cancer treatments. Cancer survival rates have improved with new treatment options, including immune checkpoint blockade (ICB); however, the objective response rate remains low. Manipulation of the microbiome is a promising approach to improving cancer outcomes, but the effect of age is understudied. Here, we sought to understand whether (1) specific microbes are associated with treatment response in older adults with non-small cell lung cancer (NSCLC) and (2) whether these microbes are the same as for younger adults. Next, we explored the causal effects of the microbiome on ICB response in mouse models and the relationship with blood-based markers of T-cell senescence. We conducted a prospective cohort study of adults ≥60 years with a new diagnosis of NSCLC who received any treatment modality. Stool was collected, and metagenomic whole-genome shotgun sequencing was performed. Blood T-cells were isolated, the RNA purified and then assessed for markers of senescence by nanostring. Response to treatment was determined by RECIST v1.1 criteria. Generalized linear regression was used to relate baseline microbiome abundances to treatment response and non-parametric correlations associated with CDKN2A (p16) expression to microbe abundances. To assess the causal role of the gut microbiome in ICB response, we gavaged gut microbiome samples from responders and non-responders into C57BL/6 mice to create human-microbiome avatar models. The mice were then injected with MC38 cancer cells and treated with anti-PD1 or isotype control antibodies, and tumor volume was measured over time. Biospecimens and best response data at three months were captured from 23 patients, of which five had a complete response, eight had a partial response, eight had stable disease, and two had progressive disease. Over 50 microbes were associated with a response after p-value adjustment. Responder stool was enriched for microbes associated with youth and ICB response (Bifidobacterium adolescentis, p = 2.64e-20). However, microbial taxa associated with response differed from those reported in younger populations (Firmicutes sp. CAG 145, p = 1.58e-20, Oscillibacter sp. 57-20, p = 7.96e-24). Stool from non-responders (NRs) was enriched in taxa previously linked to treatment-related toxicities and shorter progression-free survival (Streptococcus lutetiensis, p = 4.55E-24) but also contained microbes previously linked to response in younger adults (e.g., Roseburia sp. CAG 309, p = 5.16e-15). The T cell senescence marker, p16, correlated with the most enriched taxon in non-responders NRs (Streptococcus thermophilus, r = 0.45, p = 0.02), suggesting a connection between immune aging and the microbiome. Preliminary fecal transplant studies in mice showed improved ICB response in mice engrafted with stool from responders versus non-responders. Together, these data identify potential differences in the gut microbiomes of young and older adult NSCLC patients who respond to ICB. Citation Format: Daniel Spakowicz, Rebecca Hoyd, Caroline E. Wheeler, Nyelia Williams, Amna Bibi, Marium Husain, Srichandhana Rajamouli, Shankar Suman, Joseph Amann, Madison Grogan, Pooja Vibhakar, Dwight H. Owen, David P. Carbone, Ashley Rosko, Christin E. Burd, Carolyn J. Presley. Older adult-specific microbes correlate with treatment response and markers of T-cell senescence in NSCLC [abstract]. In: Proceedings of the AACR Special Conference: Aging and Cancer; 2022 Nov 17-20; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2022;83(2 Suppl_1):Abstract nr PR004.

The composition and function profile of the gut microbiota of patients with primary Sjögren's syndrome.

This healthy volunteer control-based study was conducted to explore alterations of compositions and function of gut microbiota in Chinese pSS patients. The high-throughput Illumina Miseq sequencing method, targeting the V3-V4 region of the 16S ribosomal RNA (rRNA) gene, was used to compare the microbiota communities between 30 pSS patients and 30 age-matched healthy volunteers. The intestinal dysbiosis of pSS patients was evaluated and its correlation with some disease phenotypes was analyzed. Furthermore, we performed the amino acid sequence alignment analysis to illustrate the molecular mimicry patterns of new microbial peptides. Compared with that in healthy controls, the composition and function of the gut microbiota significantly differed in pSS patients. Certain genera and species, including genera: Escherichia-Shigella, Sardovia, Veillonella, Insteinimonas, and Lactobacillales; species: Escherichia coli, Lactobacillus phage Sal3, Lactobacillus reuteri, Lactobacillus gasseri, Streptococcus lutetiensis, Streptococcus mutans, Scardovia wiggsiae, and Fusobacterrium ulcerans were found to be enriched in the feces of pSS patients, while butyrate-producing bacteria were less abundant in pSS patients. Certain genera (including Lactobacillales) and species (including Lactobacillus gasseri) were associated with disease severity and therapy resistance parameters. Autoantigen epitopes of "WPSALPT, NPARSFG, MNPARSFG, and AFGLAIGT" from aquaporin-5 were aligned perfectly with one enriched microbiota of patients with pSS, namely Escherichia coli. The composition and function of the gut microbiota significantly differed in pSS patients compared with that in healthy controls. Our study would facilitate the possible research on the role of gut microbiota in the pathogenesis of pSS.

Characterization of Lactic Acid-Producing Bacteria Isolated from Rumen: Growth, Acid and Bile Salt Tolerance, and Antimicrobial Function

Lactic acid bacteria are some of the dominant bacteria in the rumen, and they have a high ability for lactic acid production. The present study aimed to screen and evaluate the performance of culturable rumen bacteria from Chinese Holstein dairy cows as a potential probiotic or inoculant for silage production, in order to isolate ruminal lactic acid bacteria and evaluate their potential as probiotics. Three strains of Enterococcus avium (E. avium, EA1-3); three strains of Streptococcus lutetiensis (S. lutetiensis, SL1-3); and six strains of Streptococcus equinus (S. equinus, SE1-6) were successfully identified from the rumen fluid using modified De Man Rogosa sharp medium supplemented with 0.325% lactic acid. E. avium, S. lutetiensis and S. equinus are clustered in the phylogenetic tree. All the 12 Gram-positive strains reached the plateau growth phase in 6–10 h, with an OD600 at about 1.8. Both gas and acid accumulation reached plateaus at about 10–12 h in all strains, and S. equinus showed the strongest capacity. The highest lactic acid accumulation was detected in S. equinus broth (up to 219.77 μmol/L). The growth of all isolates was inhibited at pH 4.0, and EA2, SL1, SL2, SL3 and SE2 were tolerant to 0.1%, 0.2% and 0.3% bile salt. In addition, the supernatants of the strains had inhibitory effects on Escherichia coli and Staphylococcus aureus. Specifically, the S. equinus strains exhibited the strongest inhibition of the pathogens. In conclusion, these 12 strains had good potential as silage inoculants or probiotics for edible animals, especially S. equinus.

Microbiome Profile of Dogs with Stage IV Multicentric Lymphoma: A Pilot Study.

Simple SummaryLymphoma is a common type of hematopoietic cancer encountered in small animal practices. Canine multicentric lymphoma represents 80% of lymphoma cases and is characterized by a spread of the disease in multiple lymph nodes and organs as well. A causal role of the gut microbiota in disease spread has been shown in different diseases. In this study, the gut microbiome of dogs diagnosed with stage IV multicentric lymphoma has been analyzed and compared with that of healthy dogs to evaluate potential changes linked to lymphoma and disease spread.Changes in the gut microbiome can be associated with diseases and affect the overall health of an individual. In the current study, the gut microbiome profile of dogs diagnosed with advanced stages of multicentric lymphoma was compared with that of healthy dogs and analyzed. For this purpose, dogs from veterinary hospitals diagnosed with lymphoma were selected and were further narrowed down to cases of stage IV multicentric lymphoma. Fecal samples from the selected sick and healthy dogs were collected and analyzed using MiSeq sequencing. The gut microbiota in the two groups of dogs was statistically analyzed and compared. The results revealed significant differences in the microbial populations present in sick and healthy dogs. Phylum Actinobacteria and two species (Corynebacterium amycolatum and Streptococcus lutetiensis) were found in high proportions in sick dogs and may be considered as potential biomarkers for canine stage IV multicentric lymphoma. Further investigations need to be conducted to understand the mechanisms they might be involved in.

Characterization of technological properties of lactic acid bacteria isolated from Turkish Beyaz (white) cheese

A total 144 lactic acid bacteria (LAB) strains were chosen and identified from 20 samples of Turkish Beyaz cheeses to be used as a starter or bioprotective culture. Genotypic characterization of these isolates revealed the presence of distinct LAB strains belonging to 15 different species including Enterococcus faecium, Streptococcus lutetiensis, Enterococcus faecalis, Lactococcus lactis, Lacticaseibacillus paracasei, Lactiplantibacillus plantarum, Streptococcus macedonicus, Lactobacillus curvatus, Lacticaseibacillus paracasei spp. tolerans, Enterococcus durans, Lactobacillus delbrueckii spp. lactis, Enterococcus italicus, Leuconostoc pseudomesenteroides, Lactiplantibacillus paraplantarum, and Pediococcus parvulus. The LAB strains were characterized according to their technological properties. In conclusion, many of the isolated LAB have important technological properties and in particular, L. lactis L52 and S. macedonicus L36 were found to be the most promising starter culture candidates due to their high acid-producing capacity. In addition, based on the results of antimicrobial and bacteriocinogenic activity, L. lactis L54 strain could be used as a bioprotective culture. Novelty impact statement This study is one of the most comprehensive research revealing the LAB diversity of Turkish Beyaz cheese, and it has been shown that many of the isolated LAB strains might have important technological properties to be used in white brined cheese production.

Characteristics of Gut Microbiota in Patients With Clear Cell Renal Cell Carcinoma.

Different gut microbiota is implicated in different diseases, including cancer. However, gut microbiota differences between individuals with clear cell renal cell carcinoma (ccRCC) and healthy individuals are unclear. Here, we analyzed gut microbiota composition in 51 ccRCC patients and 40 healthy controls using 16S rRNA sequencing analysis. We observed that Blautia, Streptococcus, [Ruminococcus]_torques_group, Romboutsia, and [Eubacterium]_hallii_group were dominant and positively associated with ccRCC. We isolated and cultured Streptococcus lutetiensis to characterize specific gut microbiota that promotes ccRCC and found that it promoted in vitro ccRCC proliferation, migration, and invasion via the TGF-signaling pathway. Interactions identified between the gut microbiota and ccRCC suggest the gut microbiota could serve as a potential non-invasive tool for predicting ccRCC risk and also function as a cancer therapy target.

Quality and storage time of traditional dangke cheese inoculated with indigenous lactic acid bacteria isolated from Enrekang District, South Sulawesi, Indonesia

Abstract. Zakariah MA, Malaka R, Laga A, Ako A, Zakariah M, Mauliah FU. 2022. Quality and storage time of traditional dangke cheese inoculated with indigenous lactic acid bacteria isolated from Enrekang District, South Sulawesi, Indonesia. Biodiversitas 23: 3270-3276. Dangke is a traditional cheese from Enrekang District. Many research on the isolation of lactic acid bacteria (LAB) from dangke has been done without knowing the type of LAB species. This study aimed to find out the type of LAB species that have been successfully isolated and applied to dangke again. The design of this study was conducted in two stages: 1) isolated LAB species were identified by 16S rRNA sequencing; 2) effect of inoculated LAB on the quality and storage time of traditional dangke cheese. The molecular results showed that LAB from dangke included Streptococcus lutetiensis, Weissella confusa and Streptococcus equinus. Isolates type and ripening time have affected pH, organic matter, and dangke crude fat. The type of isolate can partially affect the dry matter content, and dangke crude protein. Weissella confusa can improve the quality of dangke with a ripening time of 6 days and a storage time of 3 days.

Whole-Genome Sequencing and Comparative Genomic Analysis of Antimicrobial Producing Streptococcus lutetiensis from the Rumen.

Antimicrobial peptides (AMPs) can efficiently control different microbial pathogens and show the potential to be applied in clinical practice and livestock production. In this work, the aim was to isolate AMP-producing ruminal streptococci and to characterize their genetic features through whole-genome sequencing. We cultured 463 bacterial isolates from the rumen of Nelore bulls, 81 of which were phenotypically classified as being Streptococcaceae. Five isolates with broad-range activity were genome sequenced and confirmed as being Streptococcus lutetiensis. The genetic features linked to their antimicrobial activity or adaptation to the rumen environment were characterized through comparative genomics. The genome of S. lutetiensis UFV80 harbored a putative CRISPR-Cas9 system (Type IIA). Computational tools were used to discover novel biosynthetic clusters linked to the production of bacteriocins. All bacterial genomes harbored genetic clusters related to the biosynthesis of class I and class II bacteriocins. SDS-PAGE confirmed the results obtained in silico and demonstrated that the class II bacteriocins predicted in the genomes of three S. lutetiensis strains had identical molecular mass (5197 Da). These results demonstrate that ruminal bacteria of the Streptococcus bovis/equinus complex represent a promising source of novel antimicrobial peptides.

Acrylamide Elimination by Lactic Acid Bacteria: Screening, Optimization, In Vitro Digestion, and Mechanism.

Acrylamide is a toxic compound that is formed in cooked carbohydrate-rich food. Baking, roasting, frying, and grilling are cooking methods that cause its formation in the presence of reducing sugar and asparagine. To prevent acrylamide formation or to remove it after its formation, scientists have been trying to understand acrylamide formation pathways, and methods of prevention and removal. Therefore, this study aimed to: (1) screen newly isolated LAB for acrylamide removal, (2) optimize conditions (pH, temperature, time, salt) of the acrylamide removal for selected LAB isolates using Box-Behnken design (BBD), (3) investigate the acrylamide removal abilities of selected LAB isolates under the in vitro digestion conditions using INFO-GEST2.0 model, and (4) explore the mechanism of the acrylamide removal using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS), zeta potential, transmission electron microscopy (TEM) measurement, and Fourier transform infrared spectroscopy (FTIR). Forty strains were tested in MRS broth, where Streptococcus lutetiensis and Lactiplantibacillus plantarum had the highest capability of acrylamide removal by 39% and 26%, respectively. To enhance the binding ability, both strains were tested under controlled conditions of pH (4.5, 5.5 and 6.5), temperature (32 °C, 37 °C and 42 °C), time (14, 18 and 22 h), and NaCl (0%, 1.5% and 3% w/v) using Box-Behnken design (BBD). Both strains removed more acrylamide in the range of 35–46% for S. lutetiensis and 45–55% for L. plantarum. After testing the bacterial binding ability, both strains were exposed to a simulated gastrointestinal tract environment, removing more than 30% of acrylamide at the gastric stage and around 40% at the intestinal stage. To understand the mechanism of removal, LAB cells were characterized via scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS) and transmission electron microscopy (TEM) techniques. Cell charges were characterized by zeta potential and functional groups analyzed by Fourier transform infrared spectroscopy (FTIR). Results indicated that increasing cell wall thickness improved acrylamide adsorption capacity. Both FTIR and EDS indicated that functional groups C=O, C-O, and N-H were associated with acrylamide adsorption.

Streptococcus lutetiensis Induces Autophagy via Oxidative Stress in Bovine Mammary Epithelial Cells.

Streptococcus lutetiensis, an emerging pathogen causing bovine mastitis, has not been well characterized. We reported that S. lutetiensis was pathogenic both in vivo and in vitro and caused inflammatory reactions in the mammary gland. However, roles of autophagy and oxidative stress in the pathogenesis of S. lutetiensis-induced mastitis are unclear. In this study, an autophagy model of S. lutetiensis-infected bovine mammary epithelial cells (bMECs) was used to assess oxidative stress and autophagy flux. Expressions of Beclin1, light chain 3II, and Sequestosome 1/p62 were elevated in bMECs after S. lutetiensis infection. In addition, autophagosome and lysosome formation confirmed autophagy occurred. Based on LysoTracker Red and acridine orange, lysosome degradation was blocked, and lower expressions of lysosomal-associated membrane protein 2, cathepsins D, and cathepsins L confirmed lysosomal damage. Concurrently, the nuclear factor erythroid 2-related factor 2 (Nrf2), kelch-like ECH-associated protein 1 (Keap1), heme oxygenase 1 (HO1), and NAD (P)H: quinone oxidoreductase 1 (NQO1), and basilic proteins associated with the Nrf2/Keap1 signaling pathway, were detected. Decreased keap1 and increased Nrf2, HO1, NQO1, and reactive oxygen species (ROS) indicated increased oxidative stress. Treatment with N-Acetyl-L-cysteine (NAC), an ROS inhibitor, decreased both oxidative stress and autophagy. Therefore, we concluded that S. lutetiensis caused intracellular oxidative stress and autophagy in bMECs. In addition, crosstalk between autophagy and oxidative stress affected the autophagic flux and blocked downstream autophagy. The Nrf2-keap1-p62 pathway participated in this process, with ROS acting upstream of these effects, interfering with normal cell functions.