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The purpose of the experiment was to screen probiotics with control effect on Vibrio harveyi. The experiment compared the differences in the gut microbiota between red-head disease N. albiflora and and healthy N. albiflora, and further in vitro bacteriostatic tests, drug sensitivity tests, and biosafety tests were conducted to screen autochthonous probiotic candidates that possess bacteriostatic ability on V. harveyi B0003 and were safe to N. albiflora. The results showed that intestinal microbiota between diseased and healthy N. albiflora showed huge differences, and 12 probiotic candidates were selected for antagonistic screening. Five strains, which could inhibit V. harveyi B0003, were screened by in vitro bacteriostatic tests, and their bacteriostatic ability was ranked from strong to weak in order as B. siamensis B0E14, B. velezensis DM5, B. megaterium B1M2, B. subtilis B0E9 and Enterococcus faecalis AT5. The five probiotic candidates did not have hemolytic activity, were non-harmful to N. albiflora, and were sensitive to many antibiotic drugs. The study indicates that the five antagonistic candidates have the potential to be used as probiotics for the prevention and treatment of red-head disease in N. albiflora aquaculture. [ABSTRACT FROM AUTHOR]

This study attempted to evaluate the potential for biofilm formation and the probiotic properties of lactic acid bacteria (LAB) isolated from the Carassius auratus intestine and to determine their antibacterial activity against crucial injurious bacteria of fish. The biological features test was carried out to obtain LAB with well-resistant pH, trypsin, bile and antibiotic challenge, and biofilm formation capacity. The most promising LAB isolates, y11 and y78 were identified as Lactobacillus johnsonii and Weissella confusa using 16S ribosomal RNA gene sequencing. We discovered that oral LAB additives improved immunity in the C. auratus by increasing immune-related expression of immunoglobulin M (IgM), superoxide dismutase (SOD), alkaline phosphatase (AKP), and lysozyme (LYS) in serum and interleukins (IL-10 and IL-1β), interferon-γ (IFN-γ), and tumor necrosis factor-α (TNF-α) in organs. After the introduction of Aeromonas veronii TH0426 for 15 days, the survival rate of C. auratus was determined as follows: the protection rate of group y11 was 45 %, and group y78 was 65 % when challenged with 109 CFU/mL density. This experiment successfully selected two LAB strains as the bioprotective agents and provided theoretical support for further LAB application in aquaculture.

Short chain-galactooligosaccharides (SC-GOS) is an effective proliferation factor of Bifidobacteria. Seven strains of Bifidobacteria with high utilization of SC-GOS were screened from infant fecal samples' the result of 16S rDNA identification was that one was Bifidobacterium longum subsp. infantis BI_Y46' 2 B. pseudocatenulatum (BP_Y43' BP_YA)' 2 B. bifidum (BB_Y22' BB_S7) and 2 strains of B. longum (BL_S34' BL_H26). Compared with B. infantis M63 and B. infantis ATCC 15697' the morphology of the strains was observed and the probiotic characteristics were analyzed. Thus' the probiotics with application potential were screened. The results showed that BI_Y46 had special morphology with bifurcated fimbriae' and the exopolysaccharide yield of BB_Y22 and BP_Y43 was higher than 0.45 mg/mL. The sur¬face protein content of BL_H26 was (0.74±0.07) mg/mL' the content of BB_S7 and BB_Y22 was between 0.35-0.45 mg/mL. Whereas' BP_Y43 and BB_Y22 had strong surface hydrophobicity and self-aggregation ability. BB_Y22 and BI_Y46 showed strong tolerance to the stimulation of bile salt and gastric juice. The supernatant of BI_Y46 and BB_S7 had strong inhibiting effect on Escherichia coli ATCC 25922. In summary' B. infantis BI_Y46' B. bifidum BB_Y22 and B. pseudocatenulatum BP_Y43 had good probiotic potential and provide some reference for the development of products containing galactoseoligosaccharides and Bifidobacterium. [ABSTRACT FROM AUTHOR]

Bactericidal/permeability-increasing protein (BPI) and lipopolysaccharide-binding protein (LBP) are a group of antibacterial proteins that play an important role in the host's innate immune defense against pathogen infection. In this study, two BPI/LBPs, named ToBPI1/LBP (1434 bp in length, 478 amino acids) and ToBPI2/LBP (1422 bp in length, 474 amino acids), were identified from the golden pompano. ToBPI1/LBP and ToBPI2/LBP were significantly expressed in immune-related tissues after being challenged with Streptococcus agalactiae and Vibrio alginolyticus. The two BPI/LBPs showed significant antibacterial activity against Gram-negative Escherichia coli and Gram-positive S. agalactiae and Streptococcus iniae. In contrast, the antibacterial activity against Staphylococcus aureus, Corynebacterium glutamicum, Vibrio parahaemolyticus, V. alginolyticus and Vibrio harveyi was low and decreased with time. The membrane permeability of bacteria treated with recombinant ToBPI1/LBP and ToBPI2/LBP was significantly enhanced. These results suggest that ToBPI1/LBP and ToBPI2/LBP may play important immunological roles in the immune response of the golden pompano to bacteria. This study will provide basic information and new insights into the immune response mechanism of the golden pompano to bacteria and the function of BPI/LBP. [ABSTRACT FROM AUTHOR]

The application of semiconductor photocatalysts with multiple functions is important in the field of photocatalysis technology. As a result, a unique three-dimensional (3D) porous AgVO3/BiVO4/graphene aerogel (AgVO3/BiVO4/GA) was fabricated by using in situ ion exchange and a hydrothermal strategy. The obtained AgVO3/BiVO4/GA shows well-organized heterostructures in which AgVO3 with a rod-like morphology is well dispersed in the 3D graphene aerogel network. Moreover, AgVO3 is used as a precursor for BiVO4 growing on its surface via in situ ion exchange, which effectively avoids the agglomeration of AgVO3 and BiVO4 in the reaction. Benefitting from a reasonable composition and structure, AgVO3/BiVO4/GA possesses a brilliant photodegradation rate towards methyl orange (MO) (93% removal efficiency in 54 min) and tetracycline hydrochloride (TCH) (approximately 92% removal rate within 80 min) and bacteriostatic ability for E. coli (100% antiseptic rate in 30 min), as well as prominent photodegradation activity after five cycles. In addition, E. coli was used as an ecological indicator to evaluate the aquatic toxicity of TCH, and the results confirm that the prepared AgVO3/BiVO4/GA composite can effectively reduce the aquatic toxicity of TCH. A 3D porous AgVO3/BiVO4@GA was fabricated by an in situ ion exchange method. In the as-prepared AgVO3/BiVO4@GA photocatalyst, GA with a 3D macrostructure, porous channels and excellent electrical conductivity can efficiently support AgVO3 and facilitate cyclic regeneration, improve the mass transfer of reactants/products and promote the photogenerated charge separation rate in the photocatalytic process. Furthermore, benefitting from the ion exchange between Ag+ and Bi3+, the BiVO4 can be well dispersed on AgVO3, which avoids the agglomeration of AgVO3 and BiVO4 and further enhances the photocatalytic performance and cyclic stability of AgVO3/BiVO4@GA. [ABSTRACT FROM AUTHOR]

As a new species of Bacillus, B. velezensis has attracted much attention because of its wide distribution in nature, strong enzyme production ability, rich secondary metabolites, stress resistance and high antibacterial activity. B. velezensis can promote the growth of animals and plants and effectively prevent and control animal and plant diseases. It has been widely studied and applied in agriculture such as biological prevention and control, feed processing, aquaculture and so on. The paper reviews the biological characteristics of B. velezensis and its application in agriculture, in order to provide reference ideas for the related research of B. velezensis and provide important theoretical basis for the development of its products. [ABSTRACT FROM AUTHOR]

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Bactericidal/permeability-increasing protein (BPI) and lipopolysaccharide-binding protein (LBP) are a group of antibacterial proteins that play an important role in the host’s innate immune defense against pathogen infection. In this study, two BPI/LBPs, named ToBPI1/LBP (1434 bp in length, 478 amino acids) and ToBPI2/LBP (1422 bp in length, 474 amino acids), were identified from the golden pompano. ToBPI1/LBP and ToBPI2/LBP were significantly expressed in immune-related tissues after being challenged with Streptococcus agalactiae and Vibrio alginolyticus. The two BPI/LBPs showed significant antibacterial activity against Gram-negative Escherichia coli and Gram-positive S. agalactiae and Streptococcus iniae. In contrast, the antibacterial activity against Staphylococcus aureus, Corynebacterium glutamicum, Vibrio parahaemolyticus, V. alginolyticus and Vibrio harveyi was low and decreased with time. The membrane permeability of bacteria treated with recombinant ToBPI1/LBP and ToBPI2/LBP was significantly enhanced. These results suggest that ToBPI1/LBP and ToBPI2/LBP may play important immunological roles in the immune response of the golden pompano to bacteria. This study will provide basic information and new insights into the immune response mechanism of the golden pompano to bacteria and the function of BPI/LBP.

Sapindus mukorossi Gaertn is also known as Mu Huanzi, You Huanzi, soap tree, etc. The pericarp of Sapindus mukorossi contains many saponins, which is a type of natural non-ionic surfactant. Its extract has vigorous surface activity and biological activities such as bacteriostasis, oxidation resistance, and free radical scavenging. The Sapindus mukorossi extract is an environmentally friendly washing product that microorganisms can be rapidly decompose in nature without any environmental pollution.This study aims to investigate the effects of E-beam and Co60-γ irradiation on the total saponins content in the crude extract of the S mukorossi. The S mukorossi powder is irradiated with E-beam and Co60-γ ray at doses of 0, 4, 6, 8, 10, and 12 kGy for E-beam and 0, 50, 100, 150, and 200 Gy, respectively, for Co60-γ ray. The changes in the content of total saponins in the crude extract, total detergency, and the bacteriostatic abilities before and after the irradiation were analyzed. The results showed that the content of total saponins in samples irradiated by E-beam was significantly higher than that in non-irradiated samples. The saponins yield was the highest at a radiation dose of 6 kGy, and the detergency and bacteriostatic ability were also the strongest. After lowdose Co60-γ irradiation, the total saponins in the S mukorossi crude extract, and detergency and bacteriostatic ability had no apparent change. Conclusion: E-beam irradiation at a dose of 6 kGy can effectively improve the content of total saponins in the crude extract of S mukorossi powder. In addition, its effects on detergency and bacteriostatic abilities are relatively significant. The findings provide sufficient reference data for the further development of S mukorossi commodities. [ABSTRACT FROM AUTHOR]

Lactiplantibacillus plantarum could regulate certain physiological functions through the AI-2/LuxS-mediated quorum sensing (QS) system. To explore the regulation mechanism on the growth characteristics and bacteriostatic ability of L. plantarum SS-128, a luxS mutant was constructed by a two-step homologous recombination. Compared with ΔluxS/SS-128, the metabolites of SS-128 had stronger bacteriostatic ability. The combined analysis of transcriptomics and metabolomics data showed that SS-128 exhibited higher pyruvate metabolic efficiency and energy input, followed by higher LDH level and metabolite overflow compared to ΔluxS/SS-128, resulting in stronger bacteriostatic ability. The absence of luxS induces a regulatory pathway that burdens the cysteine cycle by quantitatively drawing off central metabolic intermediaries. To accommodate this mutations, ΔluxS/SS-128 exhibited lower metabolite overflow and abnormal proliferation. These results demonstrate that the growth characteristic and metabolism of L. plantarum SS-128 are mediated by the AI-2/LuxS QS system, which is a positive regulator involved in food safety. It would be helpful to investigate more bio-preservation control potential of L. plantarum, especially when applied in food industrial biotechnology.

In order to explore the changes of main components and antibacterial properties of honey during natural ripening and provide a theoretical basis for the production of mature honey, the amylase value was determined by spectrophotometry, the components of honey were analyzed by high performance liquid chromatography (HPLC) with low- and high-concentration and caps of honey, and the antibacterial activities of honey against Escherichia coli, Staphylococcus aureus and Candida albicans were tested by plate colony counting method. The results showed that the water content of low-concentration honey was (241.12± 11.02) mg ⋅ g-1 which was significantly higher than high-concentration honey and capping honey (p<0.05). With the increasing of honey maturity, the content of proline, fructose and amylase increased significantly (p<0.05), but the content of sucrose decreased significantly (p<0.05). In vitro bacteriostasis results showed that all three honey samples displayed strong antibacterial effects on the 3 pathogens, and the inhibition rate reached more than 85%, and high concentration honey and capped honey had the better antibacterial effect against Staphylococcus aureus and Candida albicans especially (P <0.05). In conclusion, the water content, amylase activity and proline content could be used as indicators to characterize the ripe degree of honey. Honey generally had strong bacteriostatic ability, which was enhanced with the improvement of honey-ripening. [ABSTRACT FROM AUTHOR]

Lactiplantibacillus plantarum could regulate certain physiological functions through the AI-2/LuxS-mediated quorum sensing (QS) system. To explore the regulation mechanism on the growth characteristics and bacteriostatic ability of L. plantarum SS-128, a luxS mutant was constructed by a two-step homologous recombination. Compared with ΔluxS/SS-128, the metabolites of SS-128 had stronger bacteriostatic ability. The combined analysis of transcriptomics and metabolomics data showed that SS-128 exhibited higher pyruvate metabolic efficiency and energy input, followed by higher LDH level and metabolite overflow compared to ΔluxS/SS-128, resulting in stronger bacteriostatic ability. The absence of luxS induces a regulatory pathway that burdens the cysteine cycle by quantitatively drawing off central metabolic intermediaries. To accommodate this mutations, ΔluxS/SS-128 exhibited lower metabolite overflow and abnormal proliferation. These results demonstrate that the growth characteristic and metabolism of L. plantarum SS-128 are mediated by the AI-2/LuxS QS system, which is a positive regulator involved in food safety. It would be helpful to investigate more bio-preservation control potential of L. plantarum, especially when applied in food industrial biotechnology. [ABSTRACT FROM AUTHOR]

This study was conducted to identify major constituents in the volatile matter from four indoor flowering plants and to evaluate them for bacteriostatic activity of the most abundant compounds. Volatile matter was collected by a dynamic collection method from Gardenia jasminoides, Ceropegia woodii, Pilea nummulariifolli, and Rhoeo purpurea. GC-MS analyses identified that the most abundant terpene compounds were á-pinene and ocimene (14.19% of total volatile matter) in G. jasminoides, á-pinene, camphene, ocimene and eucalyptole (43.91% of total volatile matter) in C. woodii, á-pinene and camphene (45.52% of total volatile matter) in P. nummulariifollia, and á-pinene, camphene and eucalyptole (46.42% of total volatile matter) in R. purpurea. These four terpene monomers have demonstrated strong bacteriostatic activity against six bacterial cultures. The most effective was á-pinene (5μl/ml) which had 100% bacteriostatic rate on all the bacterial cultures. The least effective (34% bacteriostatic rate) was eucalyptole (10μl/ml) against Saprophytic staphylococcus. [ABSTRACT FROM AUTHOR]

Sapindus mukorossi  Gaertn is also known as Mu Huanzi, You Huanzi, soap tree, etc. The pericarp of  Sapindus mukorossi  contains many saponins, which is a type of natural non-ionic surfactant. Its extract has vigorous surface activity and biological activities such as bacteriostasis, oxidation resistance, and free radical scavenging. The  Sapindus mukorossi  extract is an environmentally friendly washing product that microorganisms can be rapidly decompose in nature without any environmental pollution.This study aims to investigate the effects of E-beam and Co 60 -γ irradiation on the total saponins content in the crude extract of the  S mukorossi . The  S mukorossi  powder is irradiated with E-beam and Co 60 -γ ray at doses of 0, 4, 6, 8, 10, and 12 kGy for E-beam and 0, 50, 100, 150, and 200 Gy, respectively, for Co 60 -γ ray. The changes in the content of total saponins in the crude extract, total detergency, and the bacteriostatic abilities before and after the irradiation were analyzed. The results showed that the content of total saponins in samples irradiated by E-beam was significantly higher than that in non-irradiated samples. The saponins yield was the highest at a radiation dose of 6 kGy, and the detergency and bacteriostatic ability were also the strongest. After low-dose Co 6 -γ irradiation, the total saponins in the  S mukorossi  crude extract, and detergency and bacteriostatic ability had no apparent change. Conclusion: E-beam irradiation at a dose of 6 kGy can effectively improve the content of total saponins in the crude extract of  S mukorossi  powder. In addition, its effects on detergency and bacteriostatic abilities are relatively significant. The findings provide sufficient reference data for the further development of  S mukorossi  commodities., Competing Interests: Declaration of Conflicting Interests: The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (© The Author(s) 2022.)

Objective: To achieve better therapeutic results in burn wound infections and to examine alternatives to antibiotics, we designed this study to elaborate the role of myeloperoxidase (MPO) on infected burn wounds in rats. Approach: We compared chemical properties as well as bacteriostatic ability of MPO in different concentrations with NeutroPhase. Subsequently, we applied MPO (MPO group), NeutroPhase (NeutroPhase group), NaCl+H 2 O 2 (NaCl+H 2 O 2 group), or NaCl (control group) on rat dorsal burn wounds inoculated with methicillin-resistant Staphylococcus aureus (MRSA). Their effects on MRSA-colonized wounds were evaluated by microscopy, histologic section, and Western blot. Results: MPO produced more H + and HClO - , leading to a more acidic environment. Moreover, MPO inhibited the growth of MRSA more intensely after 6 h of inoculation ex vivo . In vivo the open wound rate in the MPO group was significantly lower, while the contraction rate and epithelialization rate of MPO group were higher than that of the control group, NaCl+H 2 O 2 group, and NeutroPhase group on day 20. The hematoxylin and eosin staining of MPO group showed better wound healing than other groups. More vascular endothelial growth factor (VEGF) was expressed in wound tissue of MPO group by Western blot. Innovation: This is the first study to use MPO for MRSA-colonized burn wound therapy. Conclusion: MPO displayed more effective bacteriostatic ability, possibly beneficial for MRSA-colonized wound healing., Competing Interests: No competing financial interests exist. The content of this article was expressly written by the authors listed. No ghostwriters were used to write this article., (Copyright 2019, Mary Ann Liebert, Inc., publishers.)

Lipocalin2, which also known as neutrophil gelatinase-associated lipocalin, is an essential component of the innate antimicrobial immune system. The aim of current study was to determine the distribution of lipocalin2, investigate the expression changes of lipocalin2 after bacterial challenge, and further explore the function of lipocalin2 during bacterial infection. Western blot, real-time quantitative PCR, immunohistochemistry, and ELISA were used to evaluate the temporospatial expression of lipocalin2. Normally, lipocalin2 can be detected mainly in the liver, spleen, kidney, thymus, and intestine. After Escherichia coli K88 challenge, both mRNA and protein levels of lipocalin2 were significantly elevated in the liver, spleen, thymus, and jejunum (P < 0.05) either in piglets or in mice. Serum lipocalin2 exerted a continuous increase from 8 h after challenge and peaked by 32 h. In addition, we found that the bacterial burden in blood and liver tissues was significantly increased (P < 0.05) in lipocalin2-deficient mice. Furthermore, our study revealed that in vitro lipocalin2 exerted obvious bacteriostatic activity, as the proliferation of E. coli K88 and Salmonella typhimurium CMCC50013 was significantly inhibited (P < 0.05) in a dose-dependent manner when treated with lipocalin2. The results suggested that the elevated lipocalin2 expression in vivo was presumed to effectively contribute protection to host innate immunity. [ABSTRACT FROM AUTHOR]