Antimicrobial peptide LL37 is a promising antibacterial candidate due to its potent antimicrobial activity with no known bacterial resistance. However, intrinsically LL37 is susceptible to degradation in wound fluids limits its effectiveness. Bacterial toxins which are released after cell lysis are found to hinder wound healing. To address these challenges, encapsulating LL37 in microspheres (MS) and loading the MS onto activated carbon (AC)-chitosan (CS) hydrogel. This advanced wound dressing not only protects LL37 from degradation but also targets bacterial toxins, aiding in the healing of chronic wound infections. First, LL37 MS and LL37-AC-CS hydrogel were prepared and characterised in terms of physicochemical properties, drug release, and peptide-polymer compatibility. Antibacterial and antibiofilm activity, bacterial toxin elimination, cell migration, and cell cytotoxicity activities were investigated. LL37-AC-CS hydrogel was effective against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. LL37-AC-CS hydrogel bound more endotoxin than AC with CS hydrogel alone. The hydrogel also induced cell migration after 72 h and showed no cytotoxicity towards NHDF after 72 h of treatment. In conclusion, the LL37-AC-CS hydrogel was shown to be a stable, non-toxic advanced wound dressing method with enhanced antimicrobial and antitoxin activity, and it can potentially be applied to chronic wound infections to accelerate wound healing.
While a group of oral commensals have been implicated in the aetiology of chronic periodontitis; the asaccharolytic Gram negative anaerobe Porphyromonas gingivalis is most commonly reported to be associated with severe forms of the disease. Although a variety of human tissues can produce a number of peptidylarginine deiminase (PAD), enzymes that convert peptide bound arginine residues to citrulline, P. gingivalis is one of the few prokaryotes known to express PAD. Protein and peptide citrullination are important in the development of rheumatoid arthritis and in recent years a number of authors have suggested a possible link between periodontitis and rheumatoid arthritis (RA). Indeed, some have linked P. gingivalis directly to RA via the action of PAD. Accordingly, the prime purpose of this study was to further characterise PAD in P. gingivalis cells particular emphasis on substrate specificity, using arginine containing peptides and RA relevant proteins.
Finding a proper transition structure for the peptide bond formation process can lead one to a better understanding of the role of ribosome in catalyzing this reaction. Using computer simulations, we performed the potential energy surface scan on the ester bond dissociation of P-site aminoacyl-tRNA and the peptide bond formation of P-site and A-site amino acids. The full fragments of initiator tRNA(i)(met) and elongator tRNA(phe) are attached to both cognate and non-cognate amino acids as the P-site substrate. The A-site amino acid for all four calculations is methionine. We used ONIOM calculations to reduce the computational cost. Our study illustrates the reduced rate of peptide bond formation for misacylated tRNA(i)(met) in the absence of ribosomal bases. The misacylated elongator tRNA(phe), however, did not show any difference in its PES compared with that for the phe-tRNA(phe). This demonstrates the structural specification of initiator tRNA(i)(met) for the amino acids side chain.
Avian influenza viruses (AIV) cause high morbidity and mortality among the poultry worldwide. Their highly mutative nature often results in the emergence of drug resistant strains, which have the potential of causing a pandemic. The virus has two immunologically important glycoproteins, hemagglutinin (HA), neuraminidase (NA), and one ion channel protein M2 which are the most important targets for drug discovery, on its surface. In order to identify a peptide-based virus inhibitor against any of these surface proteins, a disulfide constrained heptapeptide phage display library was biopanned against purified AIV sub-type H9N2 virus particles.
Obtaining pure population of neural cells from embryonic stem (ES) cells remains a challenge as little is known about the genes that govern embryonic stem cell differentiation. Using mouse ES cells, we aim to uncover the mechanisms that regulate neural differentiation of ES cells by focusing on roles played by Wnt family genes. Combining two techniques, Cre/loxP-based genetic recombination and ligand-dependent activation of Cre, we have generated transgenic ES cell lines that allow for the temporal control of expression and activity of Wnt gene (Wnt1-Ha) and Wnt antagonist (Dkk1). The ability of these cell lines in inducing the expression of transgene in undifferentiated ES cells and, more importantly, in differentiated derivatives of ES cells in vitro is evaluated.
Matched MeSH terms: Intercellular Signaling Peptides and Proteins/genetics
Cocoa-specific aroma precursors and methylpyrazines in underfermented cocoa beans obtained from fermentation induced by indigenous carboxypeptidase have been investigated. Fermentation conditions and cocoa bean components were analyzed during 0 to 3 d of fermentation. Underfermented cocoa beans were characterized as having hydrophilic peptides and free hydrophobic amino acids much higher than unfermented ones. These 2 key components of cocoa aroma precursors may be produced from the breakdown of proteins and polypeptides by endogenous carboxypeptidase during the fermentation process. The enzyme was activated during fermentation. Polypeptides of 47, 31, and 19 kDa were observed in the samples throughout the 3-d fermentation period; however, only the first 2 polypeptides were remarkably reduced during fermentation. Since the 1st day of fermentation, underfermented cocoa beans contained methylpyrazines, a dominant group of cocoa-specific aroma. This might be due to microbial activities during fermentation, observed through a decrease of pH value and an increase of temperature of cocoa beans. The concentration of tetramethylpyrazines was significantly increased during the 3 d of fermentation. This may increase the cocoa-specific flavor to the beans.
A peptide with the sequence CTLTTKLYC has previously been identified to inhibit the propagation of Newcastle disease virus (NDV) in embryonated chicken eggs and tissue culture. NDV has been classified into two main groups: the velogenic group, and mesogenic with lentogenic strains as the other group based on its dissociation constants. In this study the peptide, CTLTTKLYC, displayed on the pIII protein of a filamentous M13 phage was synthesized and mutated in order to identify the amino acid residues involved in the interactions with NDV. Mutations of C1 and K6 to A1 and A6 did not affect the binding significantly, but substitution of Y8 with A8 dramatically reduced the interaction. This suggests that Y8 plays an important role in the peptide-virus interaction. The three-dimensional structure of the peptide was determined using circular dichroism (CD), nuclear magnetic resonance (NMR), and molecular modeling. The peptide exhibited two possible conformers. One that consists of consecutive beta-turns around T2-L3-T4-T5 and K6-L7-Y8-C9. The other conformer exhibited a beta-hairpin bend type of structure with a bend around L3-T4-T5-K6.
Edible bird's nest (EBN) is made of the swiftlets' saliva, which has attracted rather more attention owing to its nutritious and medical properties. Although protein constitutes the main composition and plays an important role in EBN, few studies have focused on the proteomic profile of EBN. The purpose of this study was to produce a proteomic map and clarify common EBN proteins. Liquid-phase isoelectric focusing (LIEF) was combined with two-dimensional electrophoresis (2-DE) for comprehensive analysis of EBN proteins. From 20 to 100 protein spots were detected on 2-DE maps of EBN samples from 15 different sources. The proteins were mainly distributed in four taxa (A, B, C, and D) according to their molecular mass. Taxa A and D both contained common proteins and proteins that may be considered another characteristic of EBN. Taxon A was identified using MALDI-TOF-TOF/MS and found to be homologous to acidic mammalian chitinase-like ( Meleagris gallopavo ), which is in glycosyl hydrolase family 18.
Matched MeSH terms: Salivary Proteins and Peptides/analysis
Many species of Trichoderma have attracted interest as agents for the biological control of soil borne fungal pathogens of a range of crop plants. Research on the biochemical mechanisms associated with this application has focused on the ability of these fungi to produce enzymes which lyse fungal cell walls, and antifungal antibiotics. An important group of the latter are the non-ribosomal peptides called peptaibols. In this study Trichoderma asperellum, a strain used in biological control in Malaysia, was found to produce the peptaibol, trichotoxin. This type of peptide molecule is synthesised by a peptide synthetase (PES) enzyme template encoded by a peptide synthetase (pes) gene. Using nucleotide sequences amplified from adenylation (A-) domains as probes, to hybridise against a lambda FIXII genomic library from T. asperellum, 25 clones were recovered. These were subsequently identified as representative of four groups based on their encoding properties for specific amino acid incorporation modules in a PES. This was based on analysis of their amino acid sequences which showed up to 86% identity to other PESs including TEX 1.
Cardiovascular risk factors significantly increase the risk of developing Alzheimer disease. A possible mechanism may be via ischemic infarction-driving amyloid deposition. We conducted a study to determine the presence of β-amyloid in infarct, peri-infarct, and hemispheric areas after stroke. We hypothesized that an infarct would trigger β-amyloid deposition, with deposition over time.
Loss of auditory hair cells is a major cause of deafness. The presence of auditory progenitor cells in the inner ear raises the hope for mammalian inner ear cell regeneration. In this study, we aimed to investigate the effect of growth factor supplementations, namely a combination of epidermal growth factor (EGF), insulin-like growth factor (IGF), and beta (β)-fibroblast growth factor (βFGF), on the expression of hair cell-specific markers by cells harvested from the cochlear membrane. This would provide an insight into the capability of these cells to differentiate into hair cells.
Matched MeSH terms: Intercellular Signaling Peptides and Proteins/pharmacology*
This study concerns an attempt to establish a new method for predicting antimicrobial peptides (AMPs) which are important to the immune system. Recently, researchers are interested in designing alternative drugs based on AMPs because they have found that a large number of bacterial strains have become resistant to available antibiotics. However, researchers have encountered obstacles in the AMPs designing process as experiments to extract AMPs from protein sequences are costly and require a long set-up time. Therefore, a computational tool for AMPs prediction is needed to resolve this problem. In this study, an integrated algorithm is newly introduced to predict AMPs by integrating sequence alignment and support vector machine- (SVM-) LZ complexity pairwise algorithm. It was observed that, when all sequences in the training set are used, the sensitivity of the proposed algorithm is 95.28% in jackknife test and 87.59% in independent test, while the sensitivity obtained for jackknife test and independent test is 88.74% and 78.70%, respectively, when only the sequences that has less than 70% similarity are used. Applying the proposed algorithm may allow researchers to effectively predict AMPs from unknown protein peptide sequences with higher sensitivity.
Immunoreactive adrenocorticotropin (ACTH), beta-endorphin (BEP) and corticotropin-releasing factor (CRF) were detected in human term placenta obtained from elective Caesarian surgery. The concentrations of ACTH, BEP and CRF in placenta detected by radioimmunoassay (RIA) were 2.83 +/- 0.36, 0.52 +/- 0.05 and 0.56 +/- 0.15 ng/g wet weight of tissue respectively. Pro-opiomelanocortin (POMC) peptides were also detected in the amnion and chorion membranes and in the decidua. The concentrations of ACTH were 1.72 +/- 0.20, 4.43 +/- 0.39 and 5.80 +/- 0.17 ng/g and the levels of BEP were 0.42 +/- 0.18, 0.65 +/- 0.20 and 3.66 +/- 1.10 ng/g in the amnion, chorion and decidua respectively. In contrast to placenta, immunoreactive CRF was not detected in the amnion, chorion and decidua. Immunoreactive N-acetylated BEP was also not detected in all the placental subfractions. Comparison of the amounts of both ACTH and BEP in the various placental components indicated the following distribution: decidua > chorion > placenta > amnion. In decidua, POMC peptides were present in an equi-molar ratio but in the other three placental fractions, ACTH levels were three to five-fold higher than BEP. In immunohistochemical studies, only a positive staining for ACTH was obtained for decidua. Our results confirm the presence of POMC peptides and CRF in placenta and their physiological roles in pregnancy and parturition.
Fresh samples of human whole saliva containing approximately 20-40 micrograms protein were analyzed using SDS-polyacrylamide slab gel electrophoresis systems. More than 20 protein bands were revealed by Coomassie Brilliant Blue R 250 staining. Some of the protein bands were shown to be glycoprotein-positive with PAS (periodic acid-Schiff) reagent. The protein bands with alpha-Amylase activity appeared within a molecular weight range of 120,000-180,000, which is 2 to 2.8 times higher than the normal molecular weight reported for alpha-Amylase from parotid saliva, and showed positive staining with PAS reagent. These results show that the alpha-Amylase in whole saliva appears to exist in a macromolecular form which is not dissociated in the presence of sodium dodecyl sulfate (SDS).
Matched MeSH terms: Salivary Proteins and Peptides/analysis*
The concentrations of calcium, phosphate, protein and nitrite in whole unstimulated saliva, and the salivary flow rate under fasting conditions (saliva collected at least after 6 h without food and water) were compared with those under control conditions (saliva collected within 30 min to 1 h after food). The flow rate of fasting saliva was half that of control (0.098 ml/min vs 0.208 ml/min) and no significant differences in the flow rate were observed between sexes. The concentration of nitrite under fasting conditions was 50% higher than that in control saliva (p less than 0.05). The protein concentration was decreased, but not significantly, under fasting conditions. The composition of fasting saliva with regard to calcium and phosphate concentrations was comparable to that of the control. No significant variations in these components between sexes were observed under either condition.
Matched MeSH terms: Salivary Proteins and Peptides/analysis
Conventional diuretic agents are very effective agents in relieving volume overload and congestive symptoms in chronic heart failure (CHF). However, they are associated with activation of the renin-angiotensin system (RAS) and the sympathetic nervous system and a reduction in glomerular filtration rate, all of which have been associated with adverse outcomes in CHF. Therefore, there is an increasing interest in drugs that target the natriuretic system without neurohormonal activation and deterioration of renal function. In this review, we will discuss the underlying rationale and evidence behind currently pursued strategies that target the natriuretic system. This includes the administration of natriuretic peptides (NPs) and strategies that potentiate the NP system, such as neutral endopeptidase inhibition. We will also highlight some potentially important interactions of these strategies with drugs that target the RAS.
Moringa oleifera is a miracle plant with many nutritional and medicinal properties. Chemopreventive values of the combined mixture of moringa leaves and seed residue (MOLSr) at different ratios (M1S9, M1S1 and M9S1) were investigated. MOLSr extracts were subjected to phytochemical screening, antioxidant assays, metabolite profiling and cytotoxic activity on the primary mammary epithelial cells (PMECs), non-malignant Chang's liver cells and various human cancer cell lines (including breast, cervical, colon and liver cancer cell lines). The MOLSr ratio with the most potent cytotoxic activity was used in xenograft mice injected with MDA-MB-231 cells for in vivo tumorigenicity study as well as further protein and gene expression studies. M1S9, specifically composed of saponin and amino acid, retained the lowest antioxidant activity but the highest glucosinolate content as compared to other ratios. Cell viability decreased significantly in MCF-7 breast cancer cells and PMECs after treatment with M1S9. Solid tumor from MDA-MB-231 xenograft mice was inhibited by up to 64.5% at third week after treatment with high-dose M1S9. High-dose M1S9 significantly decreased the expression of calcineurin (CaN) and vascular endothelial cell growth factor (VEGF) proteins as well as the secreted frizzled-related protein 1 (SFRP1) and solute carrier family 39 member 6 (SLC39A6) genes. This study provides new scientific evidence for the chemoprevention potential of MOLSr extracts in a breast cancer model; however, the precise mechanism warrants further investigation.
Matched MeSH terms: Intercellular Signaling Peptides and Proteins; Intracellular Signaling Peptides and Proteins
We employed dielectrophoresis to a yeast cell suspension containing amyloid-beta proteins (Aβ) in a microfluidic environment. The Aβ was separated from the cells and characterized using the gradual dissolution of Aβ as a function of the applied dielectrophoretic parameters. We established the gradual dissolution of Aβ under specific dielectrophoretic parameters. Further, Aβ in the fibril form at the tip of the electrode dissolved at high frequency. This was perhaps due to the conductivity of the suspending medium changing according to the frequency, which resulted in a higher temperature at the tips of the electrodes, and consequently in the breakdown of the hydrogen bonds. However, those shaped as spheroidal monomers experienced a delay in the Aβ fibril transformation process. Yeast cells exposed to relatively low temperatures at the base of the electrode did not experience a positive or negative change in viability. The DEP microfluidic platform incorporating the integrated microtip electrode array was able to selectively manipulate the yeast cells and dissolve the Aβ to a controlled extent. We demonstrate suitable dielectrophoretic parameters to induce such manipulation, which is highly relevant for Aβ-related colloidal microfluidic research and could be applied to Alzheimer's research in the future.
Three human saliva genetic markers, namely, salivary peroxidase (SAPX), Pm, and Ph proteins, were investigated in the three major ethnic groups of Malaysia: Malays, Chinese, and Indians. For Pm, the allelic frequencies of Pm+ for Malays, Chinese, and Indians are 0.385 +/- 0.030, 0.282 +/- 0.026, and 0.289 +/- 0.026 respectively. For Ph, the allelic frequencies of Ph+ are 0.082 +/- 0.016 for Malays, 0.109 +/- 0.017 for Chinese, and 0.062 +/- 0.013 for Indians. For SAPX, the allelic frequencies of SAPX1 in Malays, Chinese, and Indians are 0.762 +/- 0.027, 0.755 +/- 0.027, and 0.723 +/- 0.026 respectively.
Matched MeSH terms: Salivary Proteins and Peptides/genetics*