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Department of Parasitology, Guiyang Medical College, China.
OBJECTIVE To isolate and purify the antibacterial peptides from larvae secretion of housefly (Musca domestica) and study their partial characteristics. METHODS Protein isolation and purification were performed by routine process, namely, ultrafiltration, solid phase extraction (SPE) and reversed-phase high-performance liquid chromatography (RP-HPLC). The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of the antibacterial peptides were examined. The antibacterial effect of peptides was studied in nutritive medium with different pH value(pH 5.0-10.0), divalent cations (Mg2+:(0.5 x 10(-3)- 10.0 x 10(-3))mol/L, Na+, K+:(10 x 10(-3)- 100 x 10(-3))mol/L), and serum content (12.5%-75%). RESULTS Molecular weight of the peptides was about Mr 3 000-30 000 after ultrafiltration. The fractions eluted with 20%, 30%, 70%, and 80% of acetonitrile (ACN) all showed antibacterial activity by solid phase extraction. The fractions eluted with 70% ACN showed strongest and stable st antibacterial activity which was further purified by RP-HPLC. Two sub-fractions appeared at around RT 15.5 min and 18.5 min were obtained with antibacterial activity. The MIC to those standard Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Bacillus subtilis was 32.7380, 16.3688, 65.4750 and 32.7380 microg/ml respectively. In the nutritive medium of pH 6.0-9.0, different divalent cations and serum content, the increment of A570 in experiment groups was less than 0.05, while that of the control group was greater than 0.3 (P<0.01). CONCLUSION SPE and RP-HPLC have been effective in purifying the antibacterial peptides which show strong activity in different conditions.
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Department of Parasitology, Guiyang Medical College, Guiyang, Guizhou 550004, China.
Antibacterial and antifungal peptides found in houseflies (Musca domestica) in large number are indispensable components of its immune defense mechanism. In this study the anterior tip of the larvae of housefly was cut off with a pair of fine scissors and hemolymph was collected and exuded in an ice-cold test tube. From the hemolymph an antifungal substance was isolated by solid-phase extraction combined with reverse phase-high performance liquid chromotography (RP-HPLC) and named as Musca domestica antifungal peptide-1 (MAF-1). Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) showed its molecular weight was 17 kDa. UV absorption spectra revealed that this antifungal substance possessed the characteristics of protein peptides. Analysis by fingerprint-identification and tandem mass spectrometry suggested MAF-1 was an unknown protein. Edman degradation identified the sequence of 30 amino acids of its N-terminal which matched no peptide in the MASCOT search database, indicating MAF-1 was a novel insect antifungal peptide. Mass spectrometry showed the precise molecular weight of MAF-1 was 17203.384 Da. Its isoelectric point was acidic.
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Department of Parasitology, Guiyang Medical College, Guiyang 550004, China.
OBJECTIVE To clone the cDNA sequence of Musca domestica antifungal peptide-1 (MAF-1) and analyze the amino acid sequence of MAF-1 by bioinformatics method. METHODS Based on the primer designed according to the N-terminal amino acid sequence of MAF-1, the cDNA and amino sequence of MAF-1 were obtained by the methods of RACE and NestPCR. The accuracy of the experiment was confirmed by RT-PCR The characteristic of the sequence was analyzed by bioinformatics software. RESULTS The length of the cDNA sequence of MAF-1 was 568 bp by 3'RACE, including an open reading frame (ORF) of 441 bp length and 3'UTR of 127 bp. It was a novel sequence with the submission number of HM178948 in GenBank since none homology was found when compared with other sequences by Blast. Added with the 9 amino acids that were not used to design primer, the whole sequence of MAF-1 was 156 amino acids conferred from its cDNA. 139 bp cDNA sequence was obtained by 5'RACE and the result was consistent to 3'RACE. The result of RT-PCR showed the cDNA of MAF-1 mature peptide was accurate. The bioinformatics analysis deduced that the theoretic molecular weight and isoelectric point of the whole protein sequence of MAF-1 gene were similar to those detected. The ExPASy illustrated that the MAF-1 gene had a signal peptide. There were abundant a-helix in it, the domain located between the 128 and 153 amino acid residuals. Subcellular analysis showed MAF-1 was almost in the nucleus. Predict Protein found two protein kinase C phosphorylation sites and one N-myristoylation site, and predicted that it was not a globular protein. In the end, the three dimension image of MAF-1 was set up with 3D-pssm of ExPASy. CONCLUSION The cDNA sequence and the amino acid sequence of MAF-1 have been obtained and analyzed successfully.
Department of Parasitology, Guiyang Medical College, Guiyang, Guizhou 550004, China.
Antibacterial and antifungal peptides found in houseflies (Musca domestica) in large number are indispensable components of its immune defense mechanism. In this study the anterior tip of the larvae of housefly was cut off with a pair of fine scissors and hemolymph was collected and exuded in an ice-cold test tube. From the hemolymph an antifungal substance was isolated by solid-phase extraction combined with reverse phase-high performance liquid chromotography (RP-HPLC) and named as Musca domestica antifungal peptide-1 (MAF-1). Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) showed its molecular weight was 17 kDa. UV absorption spectra revealed that this antifungal substance possessed the characteristics of protein peptides. Analysis by fingerprint-identification and tandem mass spectrometry suggested MAF-1 was an unknown protein. Edman degradation identified the sequence of 30 amino acids of its N-terminal which matched no peptide in the MASCOT search database, indicating MAF-1 was a novel insect antifungal peptide. Mass spectrometry showed the precise molecular weight of MAF-1 was 17203.384 Da. Its isoelectric point was acidic.
Pharmaceutical College, Guiyang Medical Institute, Guiyang 550004, China. qinronggui@hotmail.com
OBJECTIVE To study the immunological effect of the housefly protein in mice. METHODS The housefly protein was given orally in normal and Cyclophosphamide (CY) immunosuppressive mice, and then the indexes of the clearance rate of carbon particles and the serum hemolysin against SRBC were detected. RESULTS The housefly protein could increase HC50 significantly in the normal mice, but could not in the CY immunosppressive mice. It could increase phagocytic index significantly in the normal mice, but could not in the CY immunosuppressive mice. CONCLUSION The results suggest that the housefly protein can promote humoral immunity functions of normal mice. It has distinct preventive and cure effect on the CY immunosuppressive.
Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, P. R. China;; Tel:+86 (0)512 65880378.
The catalytic synthesis of nitrogen-containing heterocycles is of great importance to medicinal and synthetic chemists, and also a challenge for modern chemical methodology. In this paper, we report the synthesis of pyrazolidine derivatives through a domino aza-Michael/hemiacetal sequence with chiral or achiral secondary amines as organocatalysts. Thus, a series of achiral pyrazolidine derivatives were obtained with good yields (up to 90%) and high diastereoselectivities (>20:1) with pyrrolidine as an organocatalyst, and enantioenriched pyrazolidines are also achieved with good results (up to 86% yield,>10/1 regioselectivity,>20:1 dr, 99% ee) in the presence of (S)-diphenylprolinol trimethylsilyl ether catalyst.
School of Medicine, Shaoxing University, Shaoxing, Zhejiang, China; First Clinical Medical Institute, Wenzhou Medical College, Wenzhou, Zhejiang, China.
OBJECTIVE The objective was to explore the feasibility of ultrasound-microbubble-mediated hepatocyte growth factor (HGF) gene transfer for treating rat hepatic fibrosis induced by CCl(4). METHODS Forty-eight male SD rats were divided into ultrasound-microbubble-HGF group (U-M-HGF group), ultrasound-HGF group (U-HGF group), microbubble-HGF group (M-HGF group), HGF group (HGF group), CCl(4) group (control group), and normal group. The serum levels of alanine transaminase (ALT), aspartate transaminase (AST), total protein, albumin (ALB), and globulin (GLB) and the ratio of ALB/GLB were determined after treatment. The degree of hepatic fibrosis was evaluated by histopathological numerical scores. The protein expressions of HGF, collagen I, collagen III, and α-smooth muscle antibody (α-SMA) were detected by immunohistochemistry. RESULTS Ultrasound-microbubble-mediated HGF therapy significantly reduced the serum level of ALT and AST to 59.88% and 49.18% of the control group, respectively. Ultrasound-microbubble-mediated HGF therapy prevented liver fibrosis, with an obvious decrease in fibrosis areas and extracellular matrix production of collagen I, collagen III, and α-SMA. The gene therapy could induce HGF delivery into the fibrotic liver effectively. CONCLUSIONS Ultrasound-microbubble-mediated HGF gene therapy can reduce liver fibrosis, which provides a novel strategy for gene therapy of chronic liver disease.
Mol Cell Endocrinol. 2012 Nov 28;:
23201092
Xin Qi,
Wenyi Zhou,
Shuisheng Li,
Danqi Lu,
Shibai Yi,
Rui Xie,
Xiaochun Liu,
Yong Zhang,
Haoran Lin
State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals, and the Guangdong Province Key Laboratory for Aquatic Economic Animals, Sun Yat-Sen University, Guangzhou 510275, China.
Gonadotrophin-inhibitory hormone (GnIH) plays an important role in regulating of reproduction in teleosts. To clarify the mode of action of GnIH on the synthesis of gonadotropin releasing hormone (GnRH) and gonadotrophin (GtH), three GnIHR cDNAs were cloned from the goldfish brain. In situ hybridization results showed that GnIHRs were localized to the hypothalamus and pituitary. In the hypothalamus, GnIHRs were found in the NPP, NPO and NLT, whereas sGnRH neurons were reported to be located, and potentially regulated by GnIH. In the pituitary, only two GnIHRs were observed and they were localized to the PI instead of the adenohypophysis where GtH-expressing cells are localized, suggesting indirect regulation of GtH by GnIH. In vivo, intraperitoneal (i.p.) injections of synthetic goldfish GnIH-II peptide and GnIH-III peptide significantly decreased sGnRH and FSHβ mRNA levels. Only GnIH- II decreased LHβ mRNA levels significantly. In vitro, both GnIH- II and GnIH- III showed no effect on GtH synthesis, but an inhibition of GnRH-stimulated LHβ and FSHβ synthesis was observed when GnIH- III was applied to primary pituitary cells in culture. Thus, GnIH could contribute to the regulation of gonadotropin in the brain and pituitary in teleosts.
Chest. 2012 Sep 24;:
23188423
Xiaocong Fang,
Ka Li,
Xuefei Tao,
Chengshui Chen,
Xiaoying Wang,
Lingyan Wang,
Diane C Wang,
Yong Zhang,
Chunxue Bai,
Xiangdong Wang
ABSTRACT RATIONALE: Phosphoinositide 3-kinase (PI3K) plays an important role in tissue inflammatory reactions and fibrosis processes. OBJECTIVES: To evaluate the potential mechanism and therapeutic effects of PI3K inhibitor on pancreatic elastase (PE)- induced acute and chronic lung inflammation, edema and injury. METHODS: Rats were terminated at 7 or 28 days after an intra-tracheal challenge with PE and intranasal instillation with a PI3K inhibitor SHBM1009. Alterations of airway epithelial cells and myofibroblasts were studied in vitro. MEASUREMENTS: Lung inflammation, edema and injury, emphysema, and tissue remodeling were measured after PE instillation with or without treatment with PI3K inhibitor and budesonide. Cellular biological functions were monitored. MAIN RESULTS: SHBM1009 could prevent PE-induced acute lung inflammation, edema and injury and chronic lung inflammation, remodeling and emphysema. Different patterns of inhibitory effects of SHBM1009 and BEZ235 on PE-challenged epithelial cells were observed. PE per se reduced epithelial cell proliferation and stability through the inhibition of cell division rather than promoting cell death, with a dose- and time-dependent pattern. Effects of PI3K inhibitors on cells were associated with the severity of PE challenges. CONCLUSIONS: PI3K plays a critical role in the development of acute and chronic lung injury including the process of tissue remodeling and emphysema. PI3K inhibitors could be one of the new therapeutic alternatives for chronic lung diseases.1Department of Pulmonary Medicine, Zhongshan Hospital, Fudan University, Shanghai, China;2Biomedical Research Center, Zhongshan Hospital, Fudan University, Shanghai, China;3Shanghai Key Lab of Organ Transplantation, Zhongshan Hospital, Fudan University, Shanghai;4Department of Respiratory Diseases, Wenzhou Medical College and The First Hospital, Wenzhou, ChinaCorresponding author: Xiangdong Wang, MD, PhD, Professor of Respiratory Medicine. E-mail: xiangdong.wang@telia.comFunding/Support: The work was supported by Shanghai Leading Academic Discipline Project (Project Number: B115), Fudan University (Distinguished Professor Grant), and Shanghai Science & Technology Committee Grants for International Collaboration (11410708600) and Project of Science and Technology Innovation Plan in Biomedicine, National Natural Science foundation of China (H0108), and National Natural Key Science foundation of China:"Lung injury of ischemic reperfusion", 30930090.Xiaocong Fang and Ka Li contributed to this article equally as the first co-authors.
PLoS One. 2012 ;7 (11):e50226
23185583
Marc T J Johnson,
Eric J Carpenter,
Zhijian Tian,
Richard Bruskiewich,
Jason N Burris,
Charlotte T Carrigan,
Mark W Chase,
Neil D Clarke,
Sarah Covshoff,
Claude W Depamphilis,
Patrick P Edger,
Falicia Goh,
Sean Graham,
Stephan Greiner,
Julian M Hibberd,
Ingrid Jordon-Thaden,
Toni M Kutchan,
James Leebens-Mack,
Michael Melkonian,
Nicholas Miles,
Henrietta Myburg,
Jordan Patterson,
J Chris Pires,
Paula Ralph,
Megan Rolf,
Rowan F Sage,
Douglas Soltis,
Pamela Soltis,
Dennis Stevenson,
C Neal Stewart Jr,
Barbara Surek,
Christina J M Thomsen,
Juan Carlos Villarreal,
Xiaolei Wu,
Yong Zhang,
Michael K Deyholos,
Gane Ka-Shu Wong
Department of Biology, University of Toronto at Mississauga, Mississauga, Ontario, Canada.
Next-generation sequencing plays a central role in the characterization and quantification of transcriptomes. Although numerous metrics are purported to quantify the quality of RNA, there have been no large-scale empirical evaluations of the major determinants of sequencing success. We used a combination of existing and newly developed methods to isolate total RNA from 1115 samples from 695 plant species in 324 families, which represents >900 million years of phylogenetic diversity from green algae through flowering plants, including many plants of economic importance. We then sequenced 629 of these samples on Illumina GAIIx and HiSeq platforms and performed a large comparative analysis to identify predictors of RNA quality and the diversity of putative genes (scaffolds) expressed within samples. Tissue types (e.g., leaf vs. flower) varied in RNA quality, sequencing depth and the number of scaffolds. Tissue age also influenced RNA quality but not the number of scaffolds ≥1000 bp. Overall, 36% of the variation in the number of scaffolds was explained by metrics of RNA integrity (RIN score), RNA purity (OD 260/230), sequencing platform (GAIIx vs HiSeq) and the amount of total RNA used for sequencing. However, our results show that the most commonly used measures of RNA quality (e.g., RIN) are weak predictors of the number of scaffolds because Illumina sequencing is robust to variation in RNA quality. These results provide novel insight into the methods that are most important in isolating high quality RNA for sequencing and assembling plant transcriptomes. The methods and recommendations provided here could increase the efficiency and decrease the cost of RNA sequencing for individual labs and genome centers.
PLoS One. 2012 ;7 (11):e50142
23185557
Key Laboratory of Agricultural and Environmental Microbiology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.
Direct cloning of PCR fragments by TA cloning or blunt end ligation are two simple methods which would greatly benefit high-throughput (HTP) cloning constructions if the efficiency can be improved. In this study, we have developed a ribosomal binding site (RBS) switching strategy for direct cloning of PCR fragments. RBS is an A/G rich region upstream of the translational start codon and is essential for gene expression. Change from A/G to T/C in the RBS blocks its activity and thereby abolishes gene expression. Based on this property, we introduced an inactive RBS upstream of a selectable marker gene, and designed a fragment insertion site within this inactive RBS. Forward and reverse insertions of specifically tailed fragments will respectively form an active and inactive RBS, thus all background from vector self-ligation and fragment reverse insertions will be eliminated due to the non-expression of the marker gene. The effectiveness of our strategy for TA cloning and blunt end ligation are confirmed. Application of this strategy to gene over-expression, a bacterial two-hybrid system, a bacterial one-hybrid system, and promoter bank construction are also verified. The advantages of this simple procedure, together with its low cost and high efficiency, makes our strategy extremely useful in HTP cloning constructions.
Tumour Biol. 2012 Nov 20;:
23179396
Department of Hepatobiliary Surgery, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shannxi, 710032, People's Republic of China.
Although Notch1 expression has been associated with progression or prognosis in various tumors, the role of Notch1 in hepatocellular carcinoma (HCC) remains unknown. This study sought to investigate the clinicopathological and prognostic relevance of Notch1 expression in HCC as well as the underlying mechanisms responsible. HCC tissues were stained with an anti-Notch1 antibody. The invasion capacities of cells were measured using Transwell cell culture chambers. Reverse transcription PCR and/or western blot were used to evaluate the expression levels of Notch1, matrix metalloproteinase (MMP)-2, and MMP-9. Notch1 expression was downregulated by RNA interference. The activity of MMP-2/MMP-9 was quantified by enzyme-linked immunosorbent assay, and cellular apoptosis was analyzed using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. Notch1 expression was mainly localized within the cytoplasm and at the cell membrane. High Notch1 expression correlated with tumor size, tumor grade, metastasis, venous invasion, and American Joint Committee on Cancer TNM stage (P < 0.05), and patients with high levels of Notch1 expression were at a significantly increased risk for shortened survival time (P < 0.05). In vitro, the downregulation of Notch1 expression decreased the invasion capacity of HCC cells via the regulation of MMP-2 and MMP-9. The results of the MTT assay showed that downregulation of Notch1 did not affect HCC cell viability. Notch1 may represent a novel candidate marker for patient prognosis as well a molecular target for HCC therapy.
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Guangdong Provincial Key Laboratory of Pharmaceutical Bioactive Substances, Guangdong Pharmaceutical University, 280 Wai Huan Dong Road, Guangzhou Higher Education Mega Center, Guangzhou, China.
The housefly (Musca domestica) larvae have been used clinically to cure osteomyelitis, decubital necrosis, lip boil, ecthyma and malnutritional stagnation ever since the Ming/Qing Dynasty (1368 Anno Domini) till now, in China. In prior research, we have cloned and characterized a new gene of antimicrobial peptide cecropin from M. domestica larvae. This peptide was potently active against Gram-positive and Gram-negative bacteria standard strain. In the present study, we evaluated the possibility of Mdc to be a potential bactericidal agent against clinical isolates of multidrug-resistant (MDR) Escherichia coli and to elucidate the related antimicrobial mechanisms. Antimicrobial activity assays indicated a minimal inhibitory concentration (MIC) of 1.56 μM. Bactericidal kinetics at MIC showed that Mdc rapid killing of MDR E. coli. Lipopolysaccharide (LPS) dose-dependently suppressed Mdc antibacterial potency indicates that LPS is the initial binding site of Mdc in E. coli. Propidium iodide-based flow cytometry revealed that Mdc causes E. coli membrane permeabilization. Transmission electron micrographs further indicated that a remarkable damage in the bacteria's outer and inner membrane, even the leakage of cytoplasmic contents induced by Mdc. DNA binding experimental result implies that DNA is one of the possible intracellular targets of Mdc. Of note, Mdc did not show a perceptible cytotoxic effect on human red blood cells. Altogether, these results suggest that Mdc could be an excellent candidate for the development of more efficacious bactericidal agents.
Pharm Biol. 2011 Mar ;49 (3):269-75
21323479
College of Biological Science and Technology, HeiLongJiang BaYi Agricultural University, DaQing, China. huazi8541@sina.com
CONTEXT Earthworm Eisenia foetida (Lumbricus rubellus), a traditional Chinese medicine, is used for treating many diseases, and its coelomic fluid has extensive biological functions. OBJECTIVE The hemolytic, antibacterial and antitumor activities of an earthworm protein purified from coelomic fluid were investigated in vitro. MATERIALS AND METHODS We used ultrafiltration, gel chromatography, and ion exchange chromatography in sequence to isolate and purify an earthworm protein from coelomic fluid (ECFP), and ECFP was characterized by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Hemolytic assay and antibacterial tests were applied to determine the cytolytic activity of ECFP. The MTT method was carried out to evaluate the antitumor effect of ECFP on HeLa cells and LTEP-A2 cells. RESULTS ECFP, with molecular weight determined to be approximately 38.6 kilodaltons (KDa), was shown to possess significant hemolytic activity to chicken red blood cells (CRBC)(minimal hemolytic concentration 0.39 µg/mL). Antibacterial effect of ECFP obviously tested against Escherichia coli (minimal bactericidal concentration, MBC 180 µg/ mL) and Staphylococcus aureus (MBC 90 µg/mL) were observed. Moreover, ECFP notably inhibited the proliferation of HeLa cells (IC₅₀ 77 µg/mL) and LTEP-A2 cells (IC₅₀ 126 µg/mL) both in a time- and dose-dependent manner. DISCUSSION AND CONCLUSION ECFP could serve as a component of the innate defense system of earthworms against foreign organisms, and thus it has potential pharmaceutical application in the future.
Tomoko Hanawa,
Takako Osaki,
Taki Manzoku,
Minoru Fukuda,
Hayato Kawakami,
Akio Tomoda,
Shigeru Kamiya
Department of Infectious Diseases, Division of Medical Microbiology, Kyorin University, School of Medicine.
Phx-3, one of the phenoxazine derivatives, is reported to have inhibitory effect on Mycobacterium species and Chlamydia pneumoniae but not Escherichia coli, Salmonella Typhimurium, Pseudomonas aeruginosa, Staphylococcus aureus, Listeria monocytogenes. The bactericidal activities of Phx-3 against Helicobacter pylori strains have not been assessed. Then, we measured minimum inhibitory concentration of Phx-3 for Helicobacter strains and assessed the morphological and biochemical effects of Phx-3 on H. pylori. In present study, it has shown that H. pylori strains including clarithromycin resistant strain and Helicobacter musterae were killed effectively by the treatment with Phx-3. Furthermore, severe morphological changes such as membrane blebbing and formation of hollows in H. pylori were detected. In addition, induction of heat shock protein 60 was observed. Taken together, Phx-3 has antibacterial activity against Helicobacter pylori.
Department of Parasitology, Guiyang Medical College, Guiyang, Guizhou 550004, China.
Antibacterial and antifungal peptides found in houseflies (Musca domestica) in large number are indispensable components of its immune defense mechanism. In this study the anterior tip of the larvae of housefly was cut off with a pair of fine scissors and hemolymph was collected and exuded in an ice-cold test tube. From the hemolymph an antifungal substance was isolated by solid-phase extraction combined with reverse phase-high performance liquid chromotography (RP-HPLC) and named as Musca domestica antifungal peptide-1 (MAF-1). Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) showed its molecular weight was 17 kDa. UV absorption spectra revealed that this antifungal substance possessed the characteristics of protein peptides. Analysis by fingerprint-identification and tandem mass spectrometry suggested MAF-1 was an unknown protein. Edman degradation identified the sequence of 30 amino acids of its N-terminal which matched no peptide in the MASCOT search database, indicating MAF-1 was a novel insect antifungal peptide. Mass spectrometry showed the precise molecular weight of MAF-1 was 17203.384 Da. Its isoelectric point was acidic.
BMC Res Notes. 2009 Jul 15;2 (1):136
19604396
ABSTRACT: BACKGROUND: Antimicrobial peptides (AMP) are important effectors of the innate immune system. Although there is increasing evidence that AMPs influence bacteria in a multitude of ways, bacterial wall rupture plays the pivotal role in the bactericidal action of AMPs. Structurally, AMPs share many similarities with endogenous heparin-binding peptides with respect to secondary structure, cationicity, and amphipathicity. FINDINGS: In this study, we show that RQA21 (RQAREHSERKKRRRESECKAA), a cationic and hydrophilic heparin-binding peptide corresponding to the C-terminal region of extracellular superoxide dismutase (SOD), exerts antimicrobial activity against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus subtilis and Candida albicans. The peptide was also found to induce membrane leakage of negatively charged liposomes. However, its antibacterial effects were abrogated in physiological salt conditions as well as in plasma. CONCLUSION: The results provide further evidence that heparin-binding peptide regions are multifunctional, but also illustrate that cationicity alone is not sufficient for AMP function at physiological conditions. However, our observation, apart from providing a link between heparin-binding peptides and AMPs, raises the hypothesis that proteolytically generated C-terminal SOD-derived peptides could interact with, and possibly counteract bacteria. Further studies are therefore merited to study a possible role of SOD in host defence.
J Mol Model. 2010 Feb ;16 (2):327-35
19603202
Marcin Koba,
Tomasz Baczek,
Katarzyna Macur,
Leszek Bober,
Teresa Frackowiak,
Adam Buciński,
Danuta Rystok-Grabska,
Jolanta Stasiak,
Katarzyna Koba
Department of Medicinal Chemistry, Faculty of Pharmacy, Collegium Medicum, Nicolaus Copernicus University, Bydgoszcz, Poland.
Factor analysis (FA) was performed on quinolone derivatives with antibacterial activity to model relationships between molecular descriptors and microbiological activities determined on five bacterial cell lines (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus and Streptococcus pneumoniae). Molecular modeling studies were performed with the use of HyperChem software and MM+ molecular mechanics with the semi-empirical AM1 method. Factor analysis led to the extraction of two main factors, with the share of factor 1 amounting to about 76% and factor 2 to about 24% for all the parameters used in the statistical analysis. Moreover, FA results indicated that energy of orbitals lowest unoccupied molecular orbital, energy of ionization, electron affinity, electronegativity, maximum electron density, refraction and polarizability appeared to be descriptors important for the antibacterial activity of quinolones.
Trop Biomed. 2008 Dec ;25 (3):252-3
19287365
Department of Parasitology & Medical Entomology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, 50300 Kuala Lumpur, Malaysia.
A forensic entomological study conducted in an oil palm plantation in Tanjung Sepat, Selangor, Malaysia on 3 August 2007 revealed that a housefly, Musca domestica Linnaeus oviposited its eggs on a freshly dead pig. This finding indicated that housefly might play an important role in forensic investigation in determining post-mortem interval (PMI), although it was not yet found in human corpses or any animal carrion. This preliminary paper presented a first record of Musca domestica eggs found on animal carcass in the country.
Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP, Brasil.
cDNA coding for two digestive lysozymes (MdL1 and MdL2) of the Musca domestica housefly was cloned and sequenced. MdL2 is a novel minor lysozyme, whereas MdL1 is the major lysozyme thus far purified from M. domestica midgut. MdL1 and MdL2 were expressed as recombinant proteins in Pichia pastoris, purified and characterized. The lytic activities of MdL1 and MdL2 upon Micrococcus lysodeikticus have an acidic pH optimum (4.8) at low ionic strength (mu = 0.02), which shifts towards an even more acidic value, pH 3.8, at a high ionic strength (mu = 0.2). However, the pH optimum of their activities upon 4-methylumbelliferyl N-acetylchitotrioside (4.9) is not affected by ionic strength. These results suggest that the acidic pH optimum is an intrinsic property of MdL1 and MdL2, whereas pH optimum shifts are an effect of the ionic strength on the negatively charged bacterial wall. MdL2 affinity for bacterial cell wall is lower than that of MdL1. Differences in isoelectric point (pI) indicate that MdL2 (pI = 6.7) is less positively charged than MdL1 (pI = 7.7) at their pH optima, which suggests that electrostatic interactions might be involved in substrate binding. In agreement with that finding, MdL1 and MdL2 affinities for bacterial cell wall decrease as ionic strength increases.
Acta Pol Pharm. ;65 (5):565-9
19051603
Department of Pharmacognosy, University of Benin, Benin City, Nigeria. emakhuoboh@yahoo.co.uk
Phytochemical investigation was carried out on the leaves of Lecaniodiscus cupanoides Planch (Sapindaceae). The diameter of the zones of inhibition of the 90% ethanol and aqueous extracts of the leaves were compared in order to determine the relative activity of the extracts against the tested microorganisms and also to verify its claimed ethnomedicinal use in the treatment of microbial infections. Phytochemical tests were carried out employing standard procedures. The antimicrobial activity of the extract was tested against standard strains and clinical isolates of some aerobic bacteria using the agar well diffusion method. Commercial antibiotics were used as positive reference standards to determine the sensitivity of the strains. The minimum inhibitory concentration (MIC) values were also determined using the agar well diffusion method. Preliminary phytochemical studies revealed the presence of flavonoids, tannins, saponins and cardiac glycosides as the chemical classes of compounds present in the crude extract. The extracts showed inhibitory activity against clinical isolates of Bacillus subtilis. Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa Staphylococcus aureus and a standard strain of Staphylococcus aureus (NCTC 10788). The ethanol extract was more active than the aqueous extract against all the microorganisms tested, except against the clinical isolates of Staphylococcus aureus. The MIC values ranged from 2.5 to 6.25 mg/mL for all the organisms tested. The results showed that the ethanol extract was more potent than the aqueous extract. The broad spectrum of activity displayed by the extracts would appear to provide the scientific basis for the use of the leaves of Lecaniodicus cupanoides for dressing of boils, burns and cuts in ethnomedicine.
Department of Cell and Genetics, Genetic Engineering Laboratory, College of Life Science, Nankai University, Tian Jin 300071, China. nkhyjin@hotmail.com
This work describes the induction, purification and partial biochemical characterizations of an antimicrobial protein from the housefly larvae induced by ultrasonic wave. It has been purified to apparent homogeneity by ammonium sulfate precipitation followed by Sephadex G-75, Bio-gel P6 gel filtration, and CM-Sepharose Fast Flow cation exchange chromatography. The protein is a cationic protein with an apparent molecular weight of 16315 Da determined by no-denaturing electrophoresis and SDS-PAGE, respectively. Biochemical profile assays show that this protein has good thermal stability, and repeatedly frozen and defrosted durability. The optimum pH for antimicrobial activity is around pH5. The antimicrobial range of the protein includes Gram-positive, Gram-negative bacteria and some fungi. Results of the membrane permeability assays suggest that the probable mode of action of this protein is membrane-disrupting mechanism.
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