The in vitro activity of teicoplanin and A16686, two new glycopeptide antibiotics was determined against 196 isolates of anaerobic bacteria. The activity of teicoplanin and A16686, in comparison with that of vancomycin, clindamycin, erythromycin and fusidic acid was 2 to 16 times higher against the gram positive anaerobes, namely, Propionibacterium acnes, Clostridium perfringens, Clostridium difficile, Clostridium species, Peptococcus species and Peptostreptococcus species. However, Bacteroides fragilis was resistant to teicoplanin and A16686 while Bacteroides melaninogenicus and Bacteroides bivius were found to be sensitive.
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*
Antimicrobial peptides (AMPs) are expressed in various living organisms as first-line host defenses against potential harmful encounters in their surroundings. AMPs are short polycationic peptides exhibiting various antimicrobial activities. The principal antibacterial activity is attributed to the membrane-lytic mechanism which directly interferes with the integrity of the bacterial cell membrane and cell wall. In addition, a number of AMPs form a transmembrane channel in the membrane by self-aggregation or polymerization, leading to cytoplasm leakage and cell death. However, an increasing body of evidence has demonstrated that AMPs are able to exert intracellular inhibitory activities as the primary or supportive mechanisms to achieve efficient killing. In this review, we focus on the major intracellular targeting activities reported in AMPs, which include nucleic acids and protein biosynthesis and protein-folding, protease, cell division, cell wall biosynthesis, and lipopolysaccharide inhibition. These multifunctional AMPs could serve as the potential lead peptides for the future development of novel antibacterial agents with improved therapeutic profiles.
Hereditary angioedema (HAE) is a rare and potentially life threatening autosomal dominant disease characterized by recurrent episodes of cutaneous and mucosal oedema. It results from reduced expression or loss of function of CI-esterase inhibitors (C1-INH). As opposed to the more common histamine-mediated angioedema, HAE does not respond well to conventional treatments with anti-histamines, steroids and adrenaline. Early recognition and timely intervention with the correct treatment are crucial particularly preventing airway obstruction. New disease specific treatment including plasma derived or recombinant C1-INH, ecallantide and icatibant have recently emerged and its appropriate use can reduce HAE-associated mortality and morbidity. However due to its costs, these disease specific treatments have yet to reach Malaysia. Despite that no randomized clinical trial on FFP has been performed, its efficacy in treating acute attacks of HAE is only demonstrated in case studies. This case report illustrates the successful treatment of acute HAE episode with FFP in a Malaysian government hospital setting.
Neuroblastoma cell lines such as SH-SY5Y are the most frequently utilized models in neurodegenerative research, and their use has advanced the understanding of the pathology of neurodegeneration over the past few decades. In Alzheimer's disease (AD), several pathogenic mutations have been described, all of which cause elevated levels of pathological hallmarks such as amyloid-beta (Aβ). Although the genetics of Alzheimer's disease is well known, familial AD only accounts for a small number of cases in the population, with the rest being sporadic AD, which contains no known mutations. Currently, most of the in vitro models used to study AD pathogenesis only examine the level of Aβ42 as a confirmation of successful model generation and only perform comparisons between wild-type APP and single mutants of the APP gene. Recent findings have shown that the Aβ42/40 ratio in cerebrospinal fluid (CSF) is a better diagnostic indicator for AD patients than is Aβ42 alone and that more extensive Aβ formation, such as accumulation of intraneuronal Aβ, Aβ plaques, soluble oligomeric Aβ (oAβ), and insoluble fibrillar Aβ (fAβ) occurs in TgCRND8 mice expressing a double-mutant form (Swedish and Indiana) of APP, later leading to greater progressive impairment of the brain. In this study, we generated SH-SY5Y cells stably transfected separately with wild-type APP, the Swedish mutation of APP, and the Swedish and Indiana mutations of APP and evaluated the APP expression as well as the Aβ42/40 ratio in those cells. The double-mutant form of APP (Swedish/Indiana) expressed markedly high levels of APP protein and showed a high Aβ2/40 ratio compared to wild-type and single-mutant cells.
Effective novel peptide inhibitors which targeted the domain III of the dengue envelope (E) protein by blocking dengue virus (DENV) entry into target cells, were identified. The binding affinities of these peptides towards E-protein were evaluated by using a combination of docking and explicit solvent molecular dynamics (MD) simulation methods. The interactions of these complexes were further investigated by using the Molecular Mechanics-Poisson Boltzmann Surface Area (MMPBSA) and Molecular Mechanics Generalized Born Surface Area (MMGBSA) methods. Free energy calculations of the peptides interacting with the E-protein demonstrated that van der Waals (vdW) and electrostatic interactions were the main driving forces stabilizing the complexes. Interestingly, calculated binding free energies showed good agreement with the experimental dissociation constant (Kd) values. Our results also demonstrated that specific residues might play a crucial role in the effective binding interactions. Thus, this study has demonstrated that a combination of docking and molecular dynamics simulations can accelerate the identification process of peptides as potential inhibitors of dengue virus entry into host cells.
The main purpose of this paper was to determine the heterogeneity of primary isolated mononucleated cells that originated from the peripheral blood system by observing molecular markers. The isolated cells were cultured in complete medium for 4 to 7 days prior to the separation of different cell types, that is, adherent and suspension. Following a total culture time of 14 days, adherent cells activated the Cd105 gene while suspension cells activated the Sca-1 gene. Both progenitor markers, Cbfa-1 and Ostf-1, were inactivated in both suspension and adherent cells after 14-day culture compared to cells cultured 3 days in designated differentiation medium. In conclusion, molecular analyses showed that primary mononucleated cells are heterogeneous, consisting of hematopoietic stem cells (suspension) and mesenchymal stem cells (adherent) while both cells contained no progenitor cells.
Matched MeSH terms: Intracellular Signaling Peptides and Proteins/genetics
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.
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
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.
Newcastle disease virus (NDV) strains can be classified as virulent or avirulent based upon the severity of the disease. Differentiation of the virus into virulent and avirulent is necessary for effective control of the disease. Biopanning experiments were performed using a disulfide constrained phage displayed heptapeptide library against three pathotypes of NDV strains: velogenic (highly virulent), mesogenic (moderately virulent) and lentogenic (avirulent). A phage clone bearing the peptide sequence SWGEYDM capable of distinguishing virulent from avirulent NDV strains was isolated. This phage clone was employed as a diagnostic reagent in a dot blot assay and it successfully detected only virulent NDV strains.
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.
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.
Alzheimer's disease (AD) is a progressive neurological disorder that impairs memory and cognitive abilities, primarily in the elderly. The burden of AD extends beyond patients, impacting families and caregivers due to the patients' reliance on assistance for daily tasks. The main features of the pathogenesis of AD are beta-amyloid plaques and neurofibrillary tangles (NFTs), that strongly correlate with oxidative stress and inflammation. NFTs result from misfolded and hyperphosphorylated tau proteins. Various studies have focused on tau phosphorylation, indicating protein phosphatase 2A (PP2A) as the primary tau phosphatase and glycogen synthase kinase-3 beta (GSK-3β) as the leading tau kinase. Experimental evidence suggests that inhibition of PP2A and increased GSK-3β activity contribute to neuroinflammation, oxidative stress, and cognitive impairment. Hence, targeting PP2A and GSK-3β with pharmacological approaches shows promise in treating AD. The use of natural compounds in the drug development for AD have been extensively studied for their antioxidant, anti-inflammatory, anti-cholinesterase, and neuroprotective properties, demonstrating therapeutic advantages in neurological diseases. Alongside the development of PP2A activator and GSK-3β inhibitor drugs, natural compounds are likely to have neuroprotective effects by increasing PP2A activity and decreasing GSK-3β levels. Therefore, based on the preclinical and clinical studies, the potential of PP2A and GSK-3β as therapeutic targets of natural compounds are highlighted in this review.
One of the critical stages of the T-cell immune response is the dimerization of the intramembrane domains of T-cell receptors (TCR). Structural similarities between the immunosuppressive domains of viral proteins and the transmembrane domains of TCR have led several authors to hypothesize the mechanism of immune response suppression by highly pathogenic viruses: viral proteins embed themselves in the membrane and act on the intramembrane domain of the TCRalpha subunit, hindering its functional oligomerization. It has also been suggested that this mechanism is used by influenza A virus in NS1-mediated immunosuppression. We have shown that the peptide corresponding to the primary structure of the potential immunosuppressive domain of NS1 protein (G51) can reduce concanavalin A-induced proliferation of PBMC cells, as well as in vitro, G51 can affect the oligomerization of the core peptide corresponding to the intramembrane domain of TCR, using AFM and small-angle neutron scattering. The results obtained using in cellulo and in vitro model systems suggest the presence of functional interaction between the NS1 fragment and the intramembrane domain of the TCR alpha subunit. We have proposed a possible scheme for such interaction obtained by computer modeling. This suggests the existence of another NS1-mediated mechanism of immunosuppression in influenza.
For centuries, macrofungi have been used as food and medicine in different parts of the world. This is mainly attributed to their nutritional value as a potential source of carbohydrates, proteins, amino acids, and minerals. In addition, they also include many bioactive metabolites which make mushrooms and truffles common components in folk medicine, especially in Africa, the Middle East, China, and Japan. The reported medicinal effects of mushrooms include anti-inflammatory effects, with anti-inflammatory compounds of mushrooms comprising a highly diversified group in terms of their chemical structure. They include polysaccharides, terpenoids, phenolic compounds, and many other low molecular weight molecules. The aims of this review are to report the different types of bioactive metabolites and their relevant producers, as well as the different mechanisms of action of mushroom compounds as potent anti-inflammatory agents.
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.