Bacillus siamensis Improves the Immune Status and Intestinal Health of Weaned Piglets by Improving Their Intestinal Microbiota.

Previous studies on the early interference of gut microbiota by Bacillus siamensis (B. siamensis) in weaned piglets are rarely reported, and the present trial is a preliminary study. This experiment was conducted to investigate the effects of B. siamensis supplementation on the growth performance, serum biochemistry, immune response, fecal short-chain fatty acids and microbiota of weaned piglets. Sixty weaned piglets were randomly divided into a control group (CON) and a B. siamensis group (BS), which were fed a basal diet and the basal diet supplemented with 5 × 1010 CFU B. siamensis per kg, respectively. Each group had 3 replicates and 10 piglets per replicate. The trial lasted for 28 days. The results showed that B. siamensis significantly increased the serum growth hormone (GH) and insulin-like growth factor (IGF) in piglets. Compared with the CON group, the levels of serum immunoglobulin and inflammatory factors in the BS group were significantly improved. In addition, the serum concentrations of zonulin and endotoxin (ET) in the BS group were lower. The dietary addition of B. siamensis significantly increased fecal short-chain fatty acid (SCFA) levels in piglets. Notably, B. siamensis improved the microbial composition by increasing beneficial genera, including Weissella, Lachnospiraceae_NK4A136_group and Bifidobacterium, and decreasing pathogenic genera, including Pantoea, Fusobacterium and Gemella, in piglet feces. Correlation analysis showed that the benefits of dietary B. siamensis supplementation were closely related to its improved microbial composition. In summary, the addition of B. siamensis can improve the immunity function, inflammatory response, gut permeability and SCFA levels of weaned piglets, which may be achieved through the improvement of their microbiota.

Dietary Resveratrol Ameliorates Hepatic Fatty Acid Metabolism and Jejunal Barrier in Offspring Induced by Maternal Oxidized Soybean Oil Challenge.

Increasing evidence indicates that maternal exposure to oxidized soybean oil (OSO) causes damage to the mother and offspring. The antioxidant resveratrol (Res) has a variety of health benefits. However, the protective effect of Res on mitigating offspring damage after maternal exposure to OSO and its mechanism remains unclear. Therefore, this study aimed to investigate the effect of Res on hepatic fatty acid metabolism and the jejunal barrier in suckling piglets after maternal OSO exposure. A total of 18 sows in late gestation were randomly assigned to three treatments. The sows were fed with a fresh soybean oil (FSO) diet, an OSO diet, or the OSO diet supplemented with 300 mg/kg Res (OSO + Res), respectively. The results showed that maternal supplementation of Res restored the mRNA levels of genes related to fatty acid metabolism and increased the activities of catalase (CAT) and total superoxide dismutase (T-SOD) in suckling piglets' livers under the OSO challenge. Moreover, the OSO + Res group restored the mRNA levels of occludin and claudin 4 in suckling piglet jejunum compared with the results of the OSO challenges. In summary, supplementation with Res improves hepatic fatty acid metabolism and intestinal barrier function of suckling piglets after maternal OSO challenge during late gestation and lactation.

Branched-chain amino acid modulation of lipid metabolism, gluconeogenesis, and inflammation in a finishing pig model: targeting leucine and valine.

Branched-chain amino acids (BCAAs) play a regulatory role in adipogenesis and energy balance. Therefore, this study aimed to investigate the impact of BCAA supplements, especially leucine (Leu) and valine (Val) supplementation, on lipid metabolism and related disorders in a finishing pig model. The results demonstrated that Leu (1%) and Val decreased serum as well as hepatic lipid accumulation. Moreover, metabolomics and lipidomics analyses revealed that Leu and Val markedly downregulated the level of various lipid species in the liver. This outcome may be explained by Leu and Val promoting cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA)/hormone-sensitive triglyceride lipase (HSL) signaling pathways. Leu and Val altered the fatty acid composition in distinct adipose tissues and decreased the levels of inflammatory factors. Additionally, they significantly decreased back fat thickness, and the results of the fatty acid profiles demonstrated that Leu and Val significantly increased the levels of monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs) while decreasing those of saturated fatty acids (SFAs), especially in back fat and abdominal fat. Besides, Leu and Val restored glucose homeostasis by suppressing gluconeogenesis through the serine/threonine protein kinase (AKT)/transcription factor forkhead box O1 (FOXO1) signaling pathway in the liver and back fat. In summary, these results suggest that Leu and Val may serve as key regulators for modulating lipid metabolism and steatosis.

The efficacy of anti-proteolytic peptide R7I in intestinal inflammation, function, microbiota, and metabolites by multi-omics analysis in murine bacterial enteritis.

Increased antibiotic resistance poses a major limitation in tackling inflammatory bowel disease and presents a large challenge for global health care. Antimicrobial peptides (AMPs) are a potential class of antimicrobial agents. Here, we have designed the potential oral route for antimicrobial peptide R7I with anti-proteolytic properties to deal with bacterial enteritis in mice. The results revealed that R7I protected the liver and gut from damage caused by inflammation. RNA-Seq analysis indicated that R7I promoted digestion and absorption in the small intestine by upregulating transmembrane transporter activity, lipid and small molecule metabolic processes and other pathways, in addition to upregulating hepatic steroid biosynthesis and fatty acid degradation. For the gut microbiota, Clostridia were significantly reduced in the R7I-treated group, and Odoribacteraceae, an efficient isoalloLCA-synthesizing strain, was the main dominant strain, protecting the gut from potential pathogens. In addition, we further discovered that R7I reduced the accumulation of negative organic acid metabolites. Overall, R7I exerted better therapeutic and immunomodulatory potential in the bacterial enteritis model, greatly reduced the risk of disease onset, and provided a reference for the in vivo application of antimicrobial peptides.

Broad-spectrum hybrid antimicrobial peptides derived from PMAP-23 with potential LPS binding ability.

Antimicrobial peptides, as an integral part of the innate immune system, kill bacteria through a special mechanism of action, making them less susceptible to drug resistance. However, Lipopolysaccharide (LPS) as the permeation barrier on the bacterial membrane, inhibits the antibacterial activity of antimicrobial peptides and triggers the inflammatory response. GWKRKRFG is an LPS binding sequence with a ß-boomerang motif that can be linked to antimicrobial peptides to enhance their LPS affinity and reduce the possibility of LPS-induced inflammatory responses. In this study, a series of hybrid peptides were designed by conjugating the reported LPS binding sequence to the C-/N-terminal sequences of the natural porcine antimicrobial peptide PMAP-23 to increase the LPS affinity of peptides. Among all the designed hybrid peptides, 4R-PP-G8 showed the best antibacterial activity, nonhemolytic activity, and excellent cell selectivity. The presence of LPS not only induced the secondary structure transformation of 4R-PP-G8 from a random structure to an α-helical structure but also reduced the antibacterial activity of 4R-PP-G8 in a dose-dependent manner, indicating the excellent binding ability of 4R-PP-G8 to LPS. The LPS/LTA binding assay further verified the interaction between the peptide and LPS. The membrane permeability test verified that 4R-PP-G8 possessed a strong capability to penetrate the bacterial membrane after interacting with LPS. More direct membrane disruption was observed under FE-SEM and TEM. In conclusion, we provided a simple and efficient method to improve the LPS binding ability of antimicrobial peptides and enhance their antimicrobial activity, resulting in the peptide 4R-PP-G8 with clinical application potential.

Lycopene improves maternal reproductive performance by modulating milk composition and placental antioxidative and immune status.

Placental health and milk quality are important for maternal reproductive performance during pregnancy and lactation. Lycopene plays an important role in antioxidation, anti-inflammation and regulating lipid metabolism. The goal of the present study was to investigate the effects of dietary lycopene supplementation in the pig model on reproductive performance, placental health and milk composition during maternal gestation and lactation. In the present study, the litter size of live piglets was increased and the litter size of dead piglets was decreased by lycopene supplementation of the diet of sows. The litter weight at birth and weaning were increased in the lycopene group. Through placental proteomics, we enriched differentially expressed proteins (DEPs), gene ontology (GO) terms, and Kyoto encyclopedia of proteins and genomes (KEGG) pathways involved in immunity, anti-inflammation, antioxidants, and lipid metabolism and transport. Furthermore, in terms of placental health, we analyzed the levels of related enzymes, metabolites and mRNA expression in the placenta. Lycopene was shown to reduce mRNA expression and the levels of placental inflammatory factors, increase the content of immunoglobulin, improve the antioxidant capacity, and improve lipid metabolism and lipid transport in the placenta. In terms of sow milk composition, lycopene increased the levels of immunoglobulins in colostrum and lactose in colostrum and milk. Overall, the results of the present study demonstrate that dietary lycopene supplementation of sows during gestation and lactation improves the reproductive performance to a certain extent; this may be due to lycopene improving the placental health and milk composition of sows.

Effects of Nutritional Restriction during Laying Period of Fat and Lean Line Broiler Breeder Hens on Meat Quality Traits of Offspring.

The offspring meat quality of hens undergoing a 25% dietary restriction treatment during the laying period were evaluated in fat and lean line breeder. A total of 768 female birds (384/line) were randomly assigned to four groups (12 replicates/group, 16 birds/replicates). Maternal feed restriction (MFR) and normal started at 27 weeks of age. Offspring broilers were fed ad libitum. The offspring meat quality traits and muscle fiber morphology in different periods were measured. At birth, significant interactions were found on breast muscle fiber morphology (p < 0.05). At 28 days, MFR decreased breast water content and increased thigh crude fat content, and significant interactions were observed on breast crude fat and protein contents (p < 0.05). At 56 days, MFR affected morphology of peroneus longus muscle tissue, and significant interactions were found on thigh redness at 48 h and amino acid contents in breast and thigh muscle (p < 0.05). Overall, MRF may lead to offspring birth sarcopenia. Such offspring grow more easily to deposit fat in a nutritious environment, but they will self-regulate adverse symptoms during growth and development. The two lines respond differently to maternal nutritional disturbance due to different nutritional requirements and metabolic patterns.

Lycopene Modulates Placental Health and Fetal Development Under High-Fat Diet During Pregnancy of Rats.

Lycopene plays an important role in improving immunity, promoting antioxidant capacity, and regulating fat metabolism. The placenta, an important organ for nutrients exchange between mother and child during pregnancy, directly affects fetal development. This study aims to characterize effects of lycopene on placental health and fetal development under a high-fat diet, and utilize RNA sequencing (RNA-seq) to investigate and integrate the differences of molecular pathways and biological processes in placenta. For placental health, high-fat diet during pregnancy increases placental oxidative stress, inflammation, and fat deposition. However, lycopene reduces the negative effects of high-fat diet on placenta to some extent, and further promotes fetal development. Under high-fat diet, lycopene reduces the levels of Interleukin 17 (IL-17), Interleukin 6 (IL-6), and tumor necrosis factor α (TNF-α) in placenta (p < 0.05) through the IL-17 pathway. Furthermore, lycopene supplementation in high-fat diet increases Glutaredoxin (Glrx) gene and protein expression in the placenta (p < 0.05), increases Glutathione peroxidase (GSH-Px) and Total antioxidant capacity (T-AOC) levels (p < 0.05), decreases reactive oxygen species (ROS) (p < 0.01) and Hydrogen peroxide (H2 O2 ) levels (p < 0.05) in placenta. In addition, lycopene supplementation in high fat diet increases the expression of Lep gene and protein in placenta and increases the level of leptin (p < 0.05). In terms of fetal development, the average fetal weight and fetal litter weight are increased by lycopene compared to high-diet treatment.

Rational Avoidance of Protease Cleavage Sites and Symmetrical End-Tagging Significantly Enhances the Stability and Therapeutic Potential of Antimicrobial Peptides.

Antimicrobial peptides (AMPs) are expected to solve problem of antibiotic resistance because of their distinctive nonspecific membrane-disruptive mechanism. However, clinical applications of AMPs have been precluded by their poor stability, although various complex chemical strategies have been employed to solve this problem, and this undoubtedly greatly increases the manufacturing cost. Herein, a series of novel peptides with high stability were developed based on protease-specific cleavage sites and symmetrical end-tagging. Among these peptides, II-I4-II exhibited the best antibacterial activity and the highest therapeutic index. More importantly, II-I4-II showed extremely high stability in the presence of various proteases, physiological salts and serum, and under acid, alkali, and heat conditions, and it exhibited excellent therapeutic potential in vivo. Additionally, II-I4-II exhibited a membrane-disruptive mechanism and a low propensity to induce resistance. In general, these findings contribute to the design of AMPs with high stability and might accelerate clinical applications of AMPs.

Characterization of an antibacterial dodecapeptide from pig as a potential food preservative and its antibacterial mechanism.

Antimicrobial peptides are believed to be promising bio-preservatives to prevent microbial spoilage through food processing and preservation. With the aim of developing short peptides with broad-spectrum antimicrobial activity and revealing their potential antimicrobial mechanism, a novel class of dodecapeptides were designed by introducing Trp into the hydrophilic face of RI12, a truncated α-helical peptide of porcine myeloid antimicrobial peptide-36 (PMAP-36). The antimicrobial activity study indicated that Trp endowed the peptides with higher antimicrobial potency, and the net charge of +5 was sufficient for the dodecapeptides to exert antimicrobial action. Taking hemolytic activity into consideration, the most promising peptide RI12[K3W] (RLWKIGKVLKWI-NH2) was screened with high antimicrobial activity and non-toxicity. The antimicrobial mechanism study revealed that RI12[K3W] possessed the ability to bind to LPS components and enhance membrane permeability, which was verified by membrane penetration assays. Flow cytometry and electron microscopy further confirmed that RI12[K3W] killed bacterial cells primarily by membrane damage. The results guide the potential application of antimicrobial peptides in the food industry as food preservatives to prevent bacterial contamination.

A Novel Adsorbent Albite Modified with Cetylpyridinium Chloride for Efficient Removal of Zearalenone.

Zearalenone (ZEN) is a non-steroidal estrogenic mycotoxin and constitutes a potential health threat to humans and livestock. This study aimed to explore the potential of albite modified by the cationic surfactant cetylpyridinium chloride (CPC) as ZEN adsorbent. The organoalbite (OA) was characterized by SEM analysis, XRD analysis, FTIR spectroscopy, thermal analysis, and BET gas sorption measurement. In vitro adsorption of ZEN by OA was carried out by simulating the pH conditions of the gastrointestinal tract. The characterization results showed that the surface of OA changed from hydrophilic to hydrophobic after modification. Adsorption kinetic studies showed that ZEN adsorption behavior of OA occurred by chemisorption. The equilibrium adsorption data fitted well with the Langmuir isotherm, indicating that the adsorption process of ZEN by OA was monolayer. The maximum adsorption capacity (qm) values of OA for ZEN were 10.580 and 9.287 mg/g at pH 7 and pH 3, respectively. In addition, OA had a low desorption rate (about 2%), and co-existing amino acids (i.e., Lys and Met), vitamins (i.e., VB1 and VE), and minerals (i.e., Fe2+ and Ca2+) did not affect the removal of ZEN. These results demonstrate that OA could be a promising mycotoxin adsorbent for removing the hydrophobic, weakly polar ZEN.

Maternal dietary resveratrol alleviates weaning-associated diarrhea and intestinal inflammation in pig offspring by changing intestinal gene expression and microbiota.

Early weaning commonly results in gastrointestinal disorders, inflammation and diarrhea in infants and young animals. Resveratrol, a plant phenol, affords protection against inflammation and cancer. A porcine model was used to investigate the effects of maternal dietary resveratrol on diarrhea, intestinal inflammation and the intestinal morphology in offspring during weaning. The results showed that maternal dietary resveratrol alleviated weaning-associated intestinal inflammation and diarrhea and improved the intestinal morphology in offspring. In weaning piglets, maternal dietary resveratrol increased the proportion of butyrate-producing bacteria, such as Flavonifractor, Odoribacter and Oscillibacter, as determined by 16S rRNA sequencing. RNA-seq analysis identified 189 and 139 differentially expressed genes (DEGs) in weaning and post-weaning piglets, respectively. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that DEGs were enriched for the T cell receptor, primary immunodeficiency, mitogen-activated protein kinase (MAPK) and Ras signaling pathways in weaning piglets and for the cytokine-cytokine receptor interaction pathway and metabolism-related pathways in post-weaning piglets.

TLR2/4-mediated NF-κB pathway combined with the histone modification regulates ß-defensins and interleukins expression by sodium phenyl butyrate in porcine intestinal epithelial cells.

BACKGROUND: Host defense peptides (HDPs) possess direct antibacterial, antineoplastic, and immunomodulatory abilities, playing a vital role in innate immunity. Dietary-regulated HDP holds immense potential as a novel pathway for preventing infection. OBJECTIVE: In this study, we examined the regulation mechanism of HDPs (pEP2C, pBD-1, and pBD-3) and cytokines (IL-8 and IL-18) expression by sodium phenylbutyrate (PBA). DESIGN: The effects of PBA on HDP induction and the mechanism involved were studied in porcine intestinal epithelial cell lines (IPEC J2). RESULTS: In this study, the results showed that HDPs (pEP2C, pBD-1, and pBD-3) and cytokines (IL-8 and IL-18) expression was increased significantly upon stimulation with PBA in IPEC J2 cells. Furthermore, toll-like receptor 2 (TLR2) and TLR4 were required for the PBA-mediated upregulation of the HDPs. This process occurred and further activated the NF-κB pathway via the phosphorylation of p65 and an IκB α synthesis delay. Meanwhile, histone deacetylase (HDAC) inhibition and an increased phosphorylation of histone H3 on serine S10 also occurred in PBA-induced HDP expression independently with TLR2 and TLR4. Furthermore, p38-MAPK suppressed PBA-induced pEP2C, pBD-1 pBD-3, IL-8, and IL-18 expression, but ERK1/2 failed to abolish the regulation of pBD-3, IL-8, and IL-18. Moreover, epidermal growth factor receptor (EGFR) is involved in PBA-mediated HDP regulation. CONCLUSIONS: We concluded that PBA induced HDP and cytokine increases but did not cause an excessive pro-inflammatory response, which proceeded through the TLR2 and TLR4-NF-κB pathway and histone modification in IPEC J2 cells.

Short Symmetric-End Antimicrobial Peptides Centered on ß-Turn Amino Acids Unit Improve Selectivity and Stability.

Antimicrobial peptides (AMPs) are excellent candidates to combat the increasing number of multi- or pan-resistant pathogens worldwide based on their mechanism of action, which is different from that of antibiotics. In this study, we designed short peptides by fusing an α-helix and ß-turn sequence-motif in a symmetric-end template to promote the higher cell selectivity, antibacterial activity and salt-resistance of these structures. The results showed that the designed peptides PQ and PP tended to form an α-helical structure upon interacting with a membrane-mimicking environment. They displayed high cell selectivity toward bacterial cells over eukaryotic cells. Their activities were mostly maintained in the presence of different conditions (salts, serum, heat, and pH), which indicated their stability in vivo. Fluorescence spectroscopy and electron microscopy analyses indicated that PP and PQ killed bacterial cells through membrane pore formation, thereby damaging membrane integrity. This study revealed the potential application of these designed peptides as new candidate antimicrobial agents.

Changes in glucose metabolism and mRNA expression of IRS-2 in rats exposed to phoxim and the protective effects of vitamin E.

Research has shown that organophosphorus pesticides impair glucose homeostasis and cause insulin resistance and type 2 diabetes. The current study investigates the influence of phoxim on insulin signaling pathways and the protective effects of vitamin E. Phoxim (180 mg kg-1) and VE (200 mg kg-1) were administered orally to Sprague-Dawley rats over a period of 28 consecutive days. After exposure to phoxim, the animals showed glucose intolerance and hyperinsulinemia during glucose tolerance tests, and insulin tolerance tests demonstrated an impaired glucose-lowering effect of insulin. Phoxim increases the fasting glucose, insulin and cholesterol levels, as well as the liver hexokinase activity (HK) significantly while decreasing the high density lipoprotein (HDL) cholesterol, and glycogen content in the liver and skeletal muscles observably. Furthermore, we observed an increase of insulin resistance biomarkers and a decrease of insulin sensitivity indices. The insulin receptor substrate (IRS)-2 mRNA expressions of liver and skeletal muscles were down-regulated by phoxim, while the expression of IRS-1 showed no difference. There were no differences in triglycerides, LDL-cholesterol, and fasting glucose treated with phoxim. On the basis of biochemical and molecular findings, phoxim has been determined to impair glucose homeostasis through insulin resistance and insulin signaling pathway disruptions resulting in a reduced function of insulin in hepatocytes and muscles. VE supplementation reduced the fasting glucose, increased the glycogen content and HDL-cholesterol, but did not reduce the insulin resistance indices, when phoxim-treated rats were compared to VE supplemented rats. Overall, this study shows that vitamin E modifies the phoxim toxicity in rats only to a moderate degree.

Dietary resveratrol improves antioxidant status of sows and piglets and regulates antioxidant gene expression in placenta by Keap1-Nrf2 pathway and Sirt1.

BACKGROUND: Resveratrol, a plant phenol, affords protection against inflammation and oxidative stress. The objective of this study was to investigate the effects of dietary resveratrol supplementation during pregnancy and lactation on the antioxidant status of sows and piglets and on antioxidant gene expression and pathway in placenta. METHODS: Forty sows were allotted to 2 dietary treatments 20 d after breeding. Sows were fed a control diet and a control diet with 300 mg/kg resveratrol. Oxidative stress biomarkers and antioxidant enzymes were measured in the placenta, milk, and plasma of sows and piglets. Antioxidant gene expression and protein expression of Kelch-like ECH-associated protein 1-Nuclear factor E2-related factor 2 (Keap1-Nrf2), nuclear factor kappa B-p65 (NFκB-p65) and sirtuin1 (Sirt1) were quantified in the placenta. RESULTS: Dietary resveratrol increased the litter and piglets weaning weights. Antioxidant status in the milk, placenta and plasma of sows and piglets was partially improved by dietary resveratrol. In placenta, Nrf2 protein expression was increased and Keap1 protein expression was decreased by dietary resveratrol. The mRNA expression of antioxidant genes including catalase (CAT), glutathione peroxidase 1 (GPX1), GPX4, superoxide dismutase 1 (SOD1) and heme oxygenase 1 (HO1), and phase 2 detoxification genes, including glutamate-cysteine ligase modifier (GCLM), microsomal glutathione S-transferase 1(MGST1) and UDP glucuronosyltransferase family 1 member A1 (UGT1A1), was increased by dietary resveratrol. Dietary resveratrol also increased Sirt1 and phosphorylated NFκB-p65 protein expression in the placenta. We failed to observe any influences of dietary resveratrol on pro-inflammatory cytokine levels, including those of interleukin 1ß (IL-1ß), IL-6, IL-8 and tumor necrosis factor α (TNF-α). However, we observed that the mRNA expression of IL-8 in placenta was reduced by maternal resveratrol. In addition, dietary resveratrol showed interactive effects with day of lactation on activities of SOD and CAT and levels of malonaldehyde (MDA) and hydrogen peroxide (H2O2) in milk. CONCLUSIONS: Dietary resveratrol supplementation during pregnancy and lactation improves the antioxidant status of sows and piglets, which is beneficial to the reproductive performance of sows. Dietary resveratrol regulates placental antioxidant gene expression by the Keap1-Nrf2 pathway and Sirt1 in placenta.

Central ß-turn increases the cell selectivity of imperfectly amphipathic α-helical peptides.

Although membrane lytic antimicrobial peptides (AMPs) show enormous potential for addressing mounting global antibiotic resistance, therapeutic applications are hindered by their weak antimicrobial activity, high toxicity, salt sensitivity and poor understanding of structure-activity relationships. To investigate the effects of different parameters on the biological activities of AMPs, a rational approach was adopted to design a series of short cationic α-helical peptides comprising the Ac-WxKyWxzzyKxWyK-NH2 sequence, where x: cationic residues (Arg or Lys), y: hydrophobic residues (Ala, Val, Ile or Leu), and zz: ß-turn (rigid D-Pro-Gly turn or flexible Gly-Gly turn). The peptides showed a more helical structure as the concentration of membrane-mimetic solution increased. The peptide RL with a central D-Pro-Gly turn (x: Arg, y: Lys, zz = D-Pro-Gly) exhibited broad-spectrum antimicrobial activities (2-8 µM) against ten types of clinically relevant microorganisms and even maintained its activity in the presence of physiological salts and showed excellent selectivity toward bacterial cells over human red blood cells and mammalian cells. However, the toxicity was increased after the removal of D-Pro-Gly turn. Additionally, the bactericidal activity was reduced when the D-Pro-Gly turn was replaced by a Gly-Gly turn. Fluorescence spectroscopy and electron microscopy analyses indicated that RL and its derivatives killed microbial cells by permeabilizing the cell membrane and damaging membrane integrity. In conclusion, these findings clearly generalized a potential method for designing or optimizing AMPs, and the peptide RL is a promising therapeutic candidate to combat antibiotic resistance. STATEMENT OF SIGNIFICANCE: We proposed a rational approach to design imperfectly amphiphilic peptides and identified RL (Ac-WRKLWRpGLKRWLK-NH2) in particular that shows strong antibacterial properties, low toxicity and high salt resistance. The ß-turn unit inserted into the central position of cationic α-helical peptides, especially the D-Pro-Gly turn, significantly increase the cell selectivity of the synthetic amphiphiles. The findings demonstrate a potential method for designing and/or optimizing AMPs, which would facilitate the development of strategies to design peptide-based antimicrobial biomaterials in a variety of biotechnological and clinical applications.

Individual and combined effects of Fusarium toxins on apoptosis in PK15 cells and the protective role of N-acetylcysteine.

Deoxynivalenol (DON), zearalenone (ZEN) and fumonisin B1 (FB1) are among the most toxicologically important Fusarium toxins commonly found in nature that lead to nephrotoxicity in animals. The present study investigated that the individual and combined effects of subcytotoxic DON (0.25 µM), ZEN (20 µM) and FB1 (10 µM) on oxidative stress and apoptosis in porcine kidney cells (PK15). In addition, the protective effect of N-acetylcysteine (NAC) against the toxicity of Fusarium toxins was also evaluated. Our results showed that the activities of glutathione reductase (GR) and total superoxide dismutase (SOD) were affected by DON, ZEN and FB1, and this change in activity induced reactive oxygen species (ROS) and malondialdehyde (MDA) production, increased apoptosis and regulated the mRNA expression of Bax, Bcl-2, caspase-3, caspase-9, cytochrome c (cyto c) and P53. This study demonstrated the complexity of combined mycotoxin infection since the combination of toxins exhibited more profound defects in the oxidative stress responses and apoptosis. Moreover, NAC reduced the oxidative damage and inhibited the apoptosis induced by Fusarium toxins. It was concluded that oxidative damage and apoptosis through the mitochondria-dependent channel were the mechanisms of Fusarium toxin mediated toxicity, and NAC reversed these damages to some extent.

Effects of dietary lecithin and l-carnitine on fatty acid composition and lipid-metabolic genes expression in subcutaneous fat and longissimus thoracis of growing-finishing pigs.

A 2×2 factorial experiment was conducted to investigate the effects of dietary lecithin and l-carnitine on fatty acid composition and lipid-metabolic genes expression in subcutaneous fat and longissimus thoracis of growing-finishing pigs. 160 barrows were assigned to 4 treatments consisting of 8 replicates with 5 pigs in each. The total PUFA, C18:2n-6 and C18:3n-3 in subcutaneous fat were increased by lecithin but the effect of lecithin was dependent of l-carnitine where supplementation of lecithin together with l-carnitine decreased total PUFA, C18:2n-6 and C18:3n-3. l-Carnitine increased the intramuscular fat content when supplemented with lecithin but no effect was observed without lecithin supplementation. l-Carnitine increased the mRNA expression of CPT1A, HSL, FABP4 and CRAT; and reduced the mRNA expression of FAS and ACCα in subcutaneous fat. Lecithin increased the mRNA expression of ACCα and ME1 in longissimus thoracis. l-Carnitine increased the mRNA expression of FAS in longissimus thoracis when supplemented with lecithin but no effect was observed without lecithin supplementation.

Bactericidal efficiency and modes of action of the novel antimicrobial peptide T9W against Pseudomonas aeruginosa.

The antipseudomonal efficiency and mechanism of action of a novel engineered antimicrobial peptide, T9W, were evaluated in this study. T9W displayed high activity, with a lethal concentration (LC) of 1 to 4 µM against Pseudomonas aeruginosa, including against ciprofloxacin-, gentamicin-, and ceftazidime-resistant strains, even in the presence of 50 to 300 mM NaCl, 1 to 5 mM Ca(2+), or 0.5 to 2 mM Mg(2+). The time-kill curve (TKC) analysis demonstrated concentration-dependent activity, with T9W achieving complete killing in less than 30 min at 1× LC and in less than 5 min at 4× LC. Combination TKC analyses additionally demonstrated a synergistic effect with ciprofloxacin and gentamicin. The selectivity of T9W was further supported by its ability to specifically eliminate P. aeruginosa in a coculture with macrophages without toxicity to the mammalian cells. The results from fluorescent measurement indicated that T9W bound to lipopolysaccharide (LPS) and induced P. aeruginosa membrane depolarization, and microscopic observations and flow cytometry further indicated that T9W targeted the P. aeruginosa cell membrane and disrupted cytoplasmic membrane integrity, thereby causing cellular content release leading to cell death. This study revealed the potential usefulness of T9W as a novel antimicrobial agent against P. aeruginosa.