• Journal of Microbiology and Biotechnology
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• v.26 no.2
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• pp.421-431
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• 2016

Recently, poly-γ-glutamic acid synthetase A (pgsA) has been applied to display exogenous proteins on the surface of Lactobacillus casei or Lactococcus lactis, which results in a surface-displayed component of bacteria. However, the ability of carrying genes encoded by plasmids and the expression efficiency of recombinant bacteria can be somewhat affected by the longer gene length of pgsA (1,143 bp); therefore, a truncated gene, pgsA, was generated based on the characteristics of pgsA by computational analysis. Using murine IL-10 as an exogenous gene, recombinant Lactobacillus plantarum was constructed and the capacity of the surface-displayed protein and functional differences between exogenous proteins expressed by these strains were evaluated. Surface expression of IL-10 on both recombinant bacteria with anchorins and the higher expression levels in L. plantarum-pgsA'-IL-10 were confirmed by western blot assay. Most importantly, up-regulation of IL-1β, IL-6, TNF-α, IFN-γ, and the nuclear transcription factor NF-κB p65 in RAW264.7 cells after stimulation with Poly(I:C) or LPS was exacerbated after co-culture with L. plantarum-pgsA. By contrast, IL-10 expressed by these recombinant strains could reduce these factors, and the expression of these factors was associated with recombinant strains that expressed anchorin (especially in L. plantarum-pgsA'-IL-10) and was significantly lower compared with the anchorin-free strains. These findings indicated that exogenous proteins could be successfully displayed on the surface of L. plantarum by pgsA or pgsA', and the expression of recombinant bacteria with pgsA' was superior compared with bacteria with pgsA.

• Animal Bioscience
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• v.35 no.8
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• pp.1109-1120
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• 2022

Antibiotics used to be supplemented to animal feeds as growth promoter and as an effective strategy to reduce the burden of pathogenic bacteria present in the gastro-intestinal tract. However, in-feed antibiotics also kill bacteria that may be beneficial to the animal. Secondly, unrestricted use of antibiotics enhanced the antibiotic resistance in pathogenic bacteria. To overcome above problems, scientists are taking a great deal of measures to develop alternatives of antibiotics. There is convincing evidence that probiotics could replace in-feed antibiotics in poultry production. Because they have beneficial effects on growth performance, meat quality, bone health and eggshell quality in poultry. Better immune responses, healthier intestinal microflora and morphology which help the birds to resist against disease attack were also identified with the supplementation of probiotics. Probiotics establish cross-feeding between different bacterial strains of gut ecosystem and reduce the blood cholesterol level via bile salt hydrolase activity. The action mode of probiotics was also updated according to recently published literatures, i.e antimicrobial substances generation or toxin reduction. This comprehensive review of probiotics is aimed to highlight the beneficial effects of probiotics as a potential alternative strategy to replace the antibiotics in poultry.

• Journal of Microbiology and Biotechnology
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• v.29 no.1
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• pp.160-170
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• 2019

The lactic acid bacteria species Lactobacillus plantarum (L. plantarum) has been used extensively for vaccine delivery. Considering to the critical role of dendritic cells in stimulating host immune response, in this study, we constructed a novel CD11c-targeting L. plantarum strain with surface-displayed variable fragments of anti-CD11c, single-chain antibody (scFv-CD11c). The newly designed L. plantarum strain, named 409-aCD11c, could adhere and invade more efficiently to bone marrow-derived DCs (BMDCs) in vitro due to the specific interaction between scFv-CD11c and CD11c located on the surface of BMDCs. After incubation with BMDCs, the 409-aCD11c strain harboring a eukaryotic vector pValac-GFP could lead to more efficient expression of GFP compared with wild-type strains shown by flow cytometry analysis, indicating the enhanced translocation of pValac-GFP from L. plantarum to BMDCs. Similar results were also observed in an in vivo study, which showed that oral administration resulted in efficient expression of GFP in both Peyer's patches (PP) and mesenteric lymph nodes (MLNs) within 7 days after the last administration. In addition, the CD11c-targeting strain significantly promoted the differentiation and maturation of DCs, the differentiation of $IL-4^+$ and $IL-17A^+$ T helper (Th) cells in MLNs, as well as production of $B220^+$ $IgA^+$ B cells in the PP. In conclusion, this study developed a novel DC-targeting L. plantarum strain which could increase the ability to deliver eukaryotic expression plasmid to host cells, indicating a promising approach for vaccine study.

• Food Science of Animal Resources
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• v.38 no.2
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• pp.403-416
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• 2018

In this study, the dietary effects of probiotics with a liquid application system on meat quality and physicochemical characteristics of pigs were evaluated. A total of 80 Landrace${\times}$Yorkshire${\times}$Duroc (LYD) 3-way crossbred pigs (average age $175{\pm}5d$) were assigned to a conventional farm and a probiotics farm equipped with a liquid probiotics application system (40 pigs in each farm). The two treatments were: CON (diet without probiotics) and PRO (diet with probiotics). Dietary probiotics decreased shear force in the longissimus muscle compared to the control group (p<0.05). The treatment diet did not affect backfat thickness, carcass weight, meat color, cooking loss, water holding capacity (WHC), and drip loss. Dietary probiotics significantly reduced ash, salinity, and pH (at 5 and 15 d) (p<0.05). There was no significant effect on thiobarbituric acid reactive substance (TBARS) values. Polyunsaturated fatty acid (PUFA) and omega fatty acids (${\omega}3$ and ${\omega}6$) were significantly (p<0.05) higher in the PRO group, whereas monounsaturated fatty acid (MUFA) was decreased. The free amino acid composition, serine, lysine, histidine, and arginine levels were significantly lower in the PRO than in the control group. The treatment group exhibited higher nucleotide compounds (hypoxanthine, inosine, GMP, IMP) than the controls. Also, levels of ascorbic acid and thiamin were significantly different (p<0.05), while minerals were not significantly different between the groups. In conclusion, feeding of probiotics had effects on shear force, ash, salinity, pH, PUFA, and some amino acids which related to taste and flavor without any negative effects on the pigs' carcass traits.

• Food Science of Animal Resources
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• v.42 no.6
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• pp.981-995
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• 2022

Cognitive dysfunction is a common symptom of neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, and Huntington's disease, and is known to be caused by the structural and functional loss of neurons. Many natural agents that can improve cognitive function have been developed and assessed for efficacy using various cognitive deficit animal models. As the gut environment is known to be closely connected to brain function, probiotics are attracting attention as an effective treatment target that can prevent and mitigate cognitive deficits as a result of neurodegenerative diseases. Thus, the objective of this review is to provide useful information about the types and characteristics of cognitive deficit animal models, which can be used to evaluate the anti-cognitive effects of probiotics. In addition, this work reviewed recent studies describing the effects and treatment conditions of probiotics on cognitive deficit animal models. Collectively, this review shows the potential of probiotics as edible natural agents that can mitigate cognitive impairment. It also provides useful information for the design of probiotic treatments for cognitive deficit patients in future clinical studies.

• Journal of Microbiology and Biotechnology
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• v.30 no.4
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• pp.515-525
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• 2020

Interferon (IFN)-λ plays an essential role in mucosal cells which exhibit strong antiviral activity. Lactobacillus plantarum (L. plantarum) has substantial application potential in the food and medical industries because of its probiotic properties. Alphacoronaviruses, especially porcine epidemic diarrhea virus (PEDV) and transmissible gastroenteritis virus (TGEV), cause high morbidity and mortality in piglets resulting in economic loss. Co-infection by these two viruses is becoming increasingly frequent. Therefore, it is particularly important to develop a new drug to prevent diarrhea infected with mixed viruses in piglets. In this study, we first constructed an anchored expression vector with CWA (C-terminal cell wall anchor) on L. plantarum. Second, we constructed two recombinant L. plantarum strains that anchored IFN-λ3 via pgsA (N-terminal transmembrane anchor) and CWA. Third, we demonstrated that both recombinant strains possess strong antiviral effects against coronavirus infection in the intestinal porcine epithelial cell line J2 (IPEC-J2). However, recombinant L. plantarum with the CWA anchor exhibited a more powerful antiviral effect than recombinant L. plantarum with pgsA. Consistent with this finding, Lb.plantarum-pSIP-409-IFN-λ3-CWA enhanced the expression levels of IFN-stimulated genes (ISGs) (ISG15, OASL, and Mx1) in IPEC-J2 cells more than did recombinant Lb.plantarum-pSIP-409-pgsA'-IFN-λ3. Our study verifies that recombinant L. plantarum inhibits PEDV and TGEV infection in IPEC-J2 cells, which may offer great potential for use as a novel oral antiviral agent in therapeutic applications for combating porcine epidemic diarrhea and transmissible gastroenteritis. This study is the first to show that recombinant L. plantarum suppresses PEDV and TGEV infection of IPEC-J2 cells.

• Journal of Animal Science and Technology
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• v.58 no.7
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• pp.26.1-26.11
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• 2016

The use of probiotics for human and animal health is continuously increasing. The probiotics used in humans commonly come from dairy foods, whereas the sources of probiotics used in animals are often the animals' own digestive tracts. Increasingly, probiotics from sources other than milk products are being selected for use in people who are lactose intolerant. These sources are non-dairy fermented foods and beverages, non-dairy and non-fermented foods such as fresh fruits and vegetables, feces of breast-fed infants and human breast milk. The probiotics that are used in both humans and animals are selected in stages; after the initial isolation of the appropriate culture medium, the probiotics must meet important qualifications, including being non-pathogenic acid and bile-tolerant strains that possess the ability to act against pathogens in the gastrointestinal tract and the safety-enhancing property of not being able to transfer any antibiotic resistance genes to other bacteria. The final stages of selection involve the accurate identification of the probiotic species.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.8
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• pp.1196-1200
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• 2008

An experiment was conducted to evaluate the physiological changes of laying hens subjected to feed removal during induced molting while received probiotics in the drinking water. Post-molt performance and egg quality criteria were also studied. Ninety 78-week-old Hy-line W36 laying hens were divided into two treatment groups according to equal body weight and subjected to induced molting by continuous feed removal until around 30% BW reduction. The experiment lasted 12 wks consisting of 4-wk molting and 8-wk post-molt periods. Treatment 1 received no probiotics and was considered as the control. Treatment 2 was similar to the control except that hens received probiotics in the drinking water at 400 mg/L during feed deprivation. The results indicated that hens in both groups went out of production by Day 5. However, hens received probiotics reached 5 and 50% egg production sooner than the control (30 and 52 days vs. 31 and 54 days). Starvation during molting increased heterophil to lymphocyte (H/L) ratio, hematocrit and plasma T4 and $Na^+$ levels while plasma T3 and Cl- levels were decreased. Probiotics had no significant impact on BW reduction during molt. Post-molt egg production and egg mass were higher in hens which previously received probiotics, but these responses were not significant. However, feed conversion ratio was significantly better in hens which received probiotics. Hematocrit, plasma thyroid hormone concentrations (T3 and T4) and plasma $Na^+$, $K^+$ and Cl- levels during molting were not significantly influenced by supplementation of probiotics. However, H/L ratio showed a significant (p<0.05) reduction in birds which received probiotics suggesting beneficial effects of this product for feed-deprived laying hens. No significant difference was observed in post-molt egg quality criteria.

• Journal of Microbiology and Biotechnology
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• v.29 no.9
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• pp.1335-1340
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• 2019

Probiotics, including bacteria and yeast, are live microorganisms that have demonstrated beneficial effects on human health. Recently, probiotic bacteria are constantly being studied and their applications are also being considered in promising adjuvant treatments for various intestinal diseases. Clinical trials and in vivo experiments have extended our current understanding of the important roles that probiotics play in human gut microbiomeassociated diseases. It has been documented through many clinical trials that probiotics could shape the intestinal microbiota leading to potential control of multiple bowel diseases and promotion of overall wellness. In this review, we focused on the relationship between probiotics and the human gut microbiota and its roles in gut microbiome-associated diseases. Here, we also discuss future directions and research areas that need further elucidation in order to better understand the roles of probiotics in the treatment of intestinal diseases.

• Food Science of Animal Resources
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• v.44 no.2
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• pp.255-268
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• 2024

Probiotic products have long been recognized for their health benefits. Additionally, milk has held a longstanding reputation as a dairy product that offers high-quality proteins and essential micronutrients. As awareness of the impact of food on health grows, interest in functional products such as probiotic dairy products is on the rise. Fermentation, a time-honored technique used to enhance nutritional value and food preservation, has been used for centuries to increase nutritional value and is one of the oldest food processing methods. Historically, fermented dairy products have been used as convenient vehicle for the consumption of probiotics. However, addressing the potential drawbacks of fermentation has recently led to increase in research on probiotic dairy drinks prepared without fermentation. These non-fermented dairy drinks have the advantage of maintaining the original flavors of milk drinks, containing potential health functional probiotics, and being an alternative dairy product that is helpful for probiotics intake. Currently, research on plant-based dairy products is rapidly increasing in the market. These developments might suggest the potential for novel forms of non-fermented dairy beverages with substantial prospects in the food market. This review aims to provide an overview of milk-based dairy beverages, both fermented and non-fermented, and discuss the potential of non-fermented dairy products. This exploration paves the way for innovative approaches to deliver probiotics and nutrition to consumers.