Appl Environ Microbiol 2010, 76:7318–7321 PubMedCentralPubMedCros

Appl Environ Microbiol 2010, 76:7318–7321.PubMedCentralPubMedCrossRef 43. Ge B, White DG, McDermott PF, Girard W, Zhao S, Hubert S, Meng J: Antimicrobial-resistant Selleck BV-6 Campylobacter species from retail raw meats. Appl Environ Microbiol 2003, 69:3005–3007.PubMedCentralPubMedCrossRef GANT61 order 44. Jesse TW, Englen MD, Pittenger-Alley LG, Fedorka-Cray PJ: Two distinct mutations in gyrA lead to ciprofloxacin and nalidixic acid resistance in Campylobacter coli and Campylobacter jejuni isolated from chickens and beef cattle. J Appl Microbiol 2006, 100:682–688.PubMedCrossRef

45. EUR-Lex – 32013D0652 – EN – EUR-Lex. ᅟ. ; ᅟ [http://​eur-lex.​europa.​eu/​legal-content/​EN/​TXT/​?​qid=​1404378765237&​uri=​CELEX:​32013D0652] 46. Han J, Wang Y,

Sahin O, Shen Z, Guo B, Shen J, Zhang Q: A fluoroquinolone resistance associated mutation in gyrA Affects DNA supercoiling www.selleckchem.com/products/bix-01294.html in Campylobacter jejuni. Front Cell Infect Microbiol 2012, 2:21.PubMedCentralPubMedCrossRef 47. Jolley KA, Maiden MC: BIGSdb: Scalable analysis of bacterial genome variation at the population level. BMC Bioinformatics 2010, 11:595.PubMedCentralPubMedCrossRef 48. Sheppard SK, Dallas JF, MacRae M, McCarthy ND, Sproston EL, Gormley FJ, Strachan NJC, Ogden ID, Maiden MCJ, Forbes KJ: Campylobacter genotypes from food animals, environmental sources and clinical disease in Scotland 2005/6. Int J Food Microbiol 2009, 134:96–103.PubMedCentralPubMedCrossRef Competing interests The authors declare that they have no competing interests. Authors’ contributions CR conceived the typing method, coordinated the study, conducted data analysis and drafted the manuscript; SC conducted laboratory work associated with sequencing and participated in data analysis of the Campylobacter coli species; CP conceived the methodology for recovering isolates from environmental/animals samples, performed environmental sampling and revised the manuscript; HMC coordinated the sampling strategies for collecting environmental isolates and revised the manuscript; AD performed CYTH4 the statistical analyses; FD developed the PCR assays for

identifying isolates at the species level, SL isolated strains from veterinarian samples and food products at retail; JM initiated and managed the genotyping platforms for the national surveillance system, discussed analyses, interpretation and revised the manuscript critically. All authors read and approved the final manuscript.”
“Background According to the report of FAO, due to the attack from pathogenic organisms and insect pests, 20–40% decrease in crop yield occurs which results in loss of 120 billion US $ worldwide [1]. Pest insects, being plant disease vectors reduce crop output by 10–30% either by reducing the quality and quantity of the crop production, or by serving as vectors of plant diseases [2].

Wick LM, Quadroni M, Egli T: Short- and long-term changes in prot

Wick LM, Quadroni M, Egli T: Short- and long-term changes in proteome AZD3965 chemical structure composition and kinetic properties in a culture of Escherichia coli during transition from glucose-excess to glucose-limited growth conditions in continuous culture and vice versa. Environ Microbiol 2001,3(9):588–599.PubMedCrossRef 38. Ishii

N, Nakahigashi K, Baba T, Robert M, Soga T, Kanai A, Hirasawa T, Naba M, Hirai K, Hoque A, Ho PY, Kakazu Y, Sugawara K, Igarashi S, Harada S, Masuda T, Sugiyama N, Togashi T, Hasegawa M, Takai Y, Yugi K, Arakawa K, Iwata N, Toya Y, Nakayama Y, Nishioka T, Shimizu K, Mori H, Tomita M: Multiple high-throughput analyses monitor the response of E. coli to perturbations. Science 2007,316(5824):593–597.PubMedCrossRef selleck kinase inhibitor 39. Gosset G, Zhang Z, Nayyar S, Cuevas WA, Saier MH: Transcriptome analysis of Crp-dependent catabolite control of gene expression in Escherichia coli . J Bacteriol 2004,186(11):3516–3524.PubMedCrossRef 40. Falmagne P, Wiame JM: Purification and partial characterization of two malate synthases

of Echerichia coli . Eur J Biochem 1973,37(3):415–424.PubMedCrossRef 41. Zheng D, Constantinidou C, Hobman JL, Minchin SD: Identification of the CRP regulon using in vitro and in vivo transcriptional profiling. Nucleic Acids Res 2004,32(19):5874–5893.PubMedCrossRef 42. Aviv M, Giladi H, Schreiber G, Oppenheim AB, Glaser G: Expression of the genes coding for the Escherichia coli integration host factor are controlled by growth phase, rpoS, ppGpp and by Emricasan autoregulation. Mol Microbiol 1994,14(5):1021–1031.PubMedCrossRef 43. Pellicer MT, Fernandez C, Badía J, Aguilar J, Lin EC, Baldom L: Cross-induction of glc and ace operons of Escherichia coli attributable to pathway intersection. Characterization of the glc promoter. J Biol Chem 1999,274(3):1745–1752.PubMedCrossRef 44.

Alvarez H, Kalscheuer R, Steinbuchel A: Accumulation of storage lipids in species of Rhodococcus and Nocardia and effect of inhibitors and polyethylene glycol. FETT-LIPID 1997, 99:239–246.CrossRef 45. Dauvillée D, Kinderf IS, Li Z, Kosar-Hashemi B, Samuel MS, Rampling L, Ball S, Morell MK: Role of the Escherichia coli glgX gene in glycogen metabolism. Florfenicol J Bacteriol 2005,187(4):1465–1473.PubMedCrossRef 46. Giaever HM, Styrvold OB, Kaasen I, Strøm AR: Biochemical and genetic characterization of osmoregulatory trehalose synthesis in Escherichia coli . J Bacteriol 1988,170(6):2841–2849.PubMed 47. Hengge-Aronis R, Klein W, Lange R, Rimmele M, Boos W: Trehalose synthesis genes are controlled by the putative sigma factor encoded by rpoS and are involved in stationary-phase thermotolerance in Escherichia coli . J Bacteriol 1991,173(24):7918–7924.PubMed 48. Kandror O, DeLeon A, Goldberg AL: Trehalose synthesis is induced upon exposure of Escherichia coli to cold and is essential for viability at low temperatures. Proc Natl Acad Sci USA 2002,99(15):9727–9732.PubMedCrossRef 49.

Statistical analysis The Student’s t test was used to calculate t

Statistical analysis The Student’s t test was used to calculate the statistical differences between the mean levels of polysaccharide expression of experimental samples (biofilm grown cells) and control samples (planktonic cells). A P value < 0.05 was considered significant. All statistical analyses were done using InStat software (InStat, San Diego, CA). Results Identification of a novel H. somni surface component produced during anaerobic growth To determine if there was variation in expression of membrane components under different environmental conditions, H. somni 738 was grown on CBA plates in 3-5% CO2 or

under anaerobic conditions for 48 h at 37°C. The bacteria were harvested from the plates as described in methods, and Cetavlon was added to the supernatant (0.005 M, final concentration); LOS and protein-enriched outer membranes were prepared

#Cyclosporin A nmr randurls[1|1|,|CHEM1|]# from the cell pellets [46, 47]. No substantial qualitative differences were detected in the electrophoretic profiles of the LOS or membrane proteins of bacteria grown AZD1480 order on CBA under CO2 or anaerobic conditions (data not shown), although growth of H. somni under anaerobic conditions was poor. Nonetheless, when Cetavlon was added to the supernatant of cells washed off CBA plates incubated under anaerobic conditions, a large precipitate formed, whereas little or no precipitate formed from the supernatant of cells grown on CBA in CO2 (data not shown). The Cetavlon precipitate was solubilized in distilled Resveratrol water, and greater than 90% of the precipitate was determined to be carbohydrate. However, it was not LOS, as determined by polyacrylamide gel electrophoresis and silver staining for LOS (data not shown). Electrophoresis of the Cetavlon precipitate followed by staining with alcian blue and ammoniacal silver demonstrated a heterogeneous profile, typical of high molecular size polysaccharide (Figure 1). Figure 1 Electrophoretic profiles of semi-purified Cetavlon precipitates and biofilm. Bacteria were grown anaerobically on plates or to late stationary phase, Cetavlon added, and precipitates

extracted, as described in Methods. Each extract was loaded onto 25% polyacrylamide gels, followed by electrophoresis and staining with Alcian blue and silver. Lanes: 1 and 2, 20 μg and 30 μg of EPS extracted under growth conditions favorable to biofilm formation; 3 and 4, 20 μg and 30 μg of EPS extracted from cells grown to late stationary phase in broth, respectively; 5, buffer alone; 6 and 7, 20 μg and 30 μg of EPS extracted from cells grown anaerobically on plates, respectively. Immuno-transmission electron microscopy of H. somni grown under anaerobic conditions or CO2 The polysaccharide from Cetavlon precipitates obtained from scaled up anaerobic cultures was further purified, as described in methods, and used to immunize a rabbit.

Mol Cell Proteomics 2006,5(7):1338–1347 PubMedCrossRef 31 Le Bih

Mol Cell Proteomics 2006,5(7):1338–1347.PubMedCrossRef 31. Le Bihan T, Goh T, Stewart II, Salter AM, Bukhman YV, Dharsee M, Ewing R, Wisniewski JR: Differential analysis of membrane proteins in mouse fore- and hindbrain using a label-free approach. J Proteome Res 2006,5(10):2701–2710.PubMedCrossRef 32. Qu J, Qu Y, Straubinger RM: Thiazovivin molecular weight Ultra-sensitive quantification of corticosteroids in plasma

samples using selective solid-phase extraction and reversed-phase capillary high-performance liquid chromatography/tandem mass spectrometry. Analytical Chemistry 2007,79(10):3786–3793.PubMedCrossRef 33. Yu H, Straubinger RM, Cao J, Wang H, Qu J: Ultra-sensitive quantification of paclitaxel using selective solid-phase extraction in conjunction ARRY-438162 nmr with reversed-phase capillary liquid chromatography/tandem mass spectrometry. Journal of Chromatography A 2008,1210(2):160–160.PubMedCrossRef 34. Carr SA, Anderson L: Protein Quantitation through

targeted mass spectrometry: the way out of biomarker purgatory? Clin Chem 2008,54(11):1749–1752.PubMedCrossRef 35. Cash P, 4EGI-1 Argo E, Langford PR, Kroll JS: Development of a Haemophilus two-dimensional protein database. Electrophoresis 1997,18(8):1472–1482.PubMedCrossRef 36. Link AJ, Hays LG, Carmack EB, Yates JR: Identifying the major proteome components of Haemophilus influenzae type-strain NCTC 8143. Electrophoresis 1997,18(8):1314–1334.PubMedCrossRef 37. Thoren K, Gustafsson E, Clevnert A, Larsson T, Bergstrom J, Nilsson CL: Proteomic study of non-typable Haemophilus influenzae . J Chromatogr

B Analyt Technol Biomed Life Sci 2002,782(1–2):219–226.PubMedCrossRef 38. Langen H, Takacs B, Evers S, Berndt P, Lahm HW, Wipf B, Gray C, Fountoulakis M: Two-dimensional map of the proteome of Haemophilus influenzae . Electrophoresis 2000,21(2):411–429.PubMedCrossRef 39. Gmuender H, Kuratli K, Di Padova K, Gray CP, Keck W, Evers S: Gene expression changes triggered by exposure of Haemophilus influenzae Celecoxib to novobiocin or ciprofloxacin: combined transcription and translation analysis. Genome Res 2001,11(1):28–42.PubMedCrossRef 40. Gallaher TK, Wu S, Webster P, Aguilera R: Identification of biofilm proteins in non-typeable Haemophilus Influenzae . BMC Microbiol 2006, 6:65.PubMedCrossRef 41. Kolker E, Purvine S, Galperin MY, Stolyar S, Goodlett DR, Nesvizhskii AI, Keller A, Xie T, Eng JK, Yi E, et al.: Initial proteome analysis of model microorganism Haemophilus influenzae strain Rd KW20. J Bacteriol 2003,185(15):4593–4602.PubMedCrossRef 42. Raghunathan A, Price ND, Galperin MY, Makarova KS, Purvine S, Picone AF, Cherny T, Xie T, Reilly TJ, Munson R Jr, et al.: In silico metabolic model and protein expression of Haemophilus influenzae strain Rd KW20 in rich medium. OMICS 2004,8(1):25–41.PubMedCrossRef 43. Murphy TF, Kirkham C: Biofilm formation by nontypeable Haemophilus influenzae : strain variability, outer membrane antigen expression and role of pili. BMC Microbiol 2002,2(1):7.PubMedCrossRef 44.

: Adjuvant vinorelbine plus cisplatin versus observation in patie

: Adjuvant vinorelbine plus cisplatin versus observation in patients with completely resected stage IB-IIIA non-small-cell lung cancer (Adjuvant Navelbine

International Trialist Association [ANITA]): a randomised controlled trial. Lancet Oncol 2006, 7:719–727.PubMedCrossRef 8. Winton T, Livingston R, Johnson D, Rigas J, Johnston M, Butts C, Cormier Y, Goss G, Inculet R, Vallieres E, et al.: Vinorelbine plus cisplatin vs. observation in resected non-small-cell lung cancer. N Engl J Med 2005, 352:2589–2597.PubMedCrossRef 9. Butts AR-13324 research buy CA, Ding K, Seymour L, Twumasi-Ankrah P, Graham B, Gandara D, Johnson DH, Kesler KA, Green M, Vincent M, et al.: Randomized phase III trial of vinorelbine plus cisplatin selleck compound compared with observation in completely XAV-939 ic50 resected stage IB and II non-small-cell lung cancer: updated survival analysis of JBR-10. J Clin Oncol 28:29–34. 10. Arriagada R, Bergman B, Dunant A, Le Chevalier T, Pignon JP, Vansteenkiste J: Cisplatin-based adjuvant chemotherapy in patients with completely resected non-small-cell lung cancer. N Engl J Med 2004, 350:351–360.PubMedCrossRef 11. Arriagada R, Dunant

A, Pignon JP, Bergman B, Chabowski M, Grunenwald D, Kozlowski M, Le Pechoux C, Pirker R, Pinel MI, et al.: Long-term results of the international adjuvant lung cancer trial evaluating PLEKHM2 adjuvant Cisplatin-based chemotherapy in resected

lung cancer. J Clin Oncol 28:35–42. 12. Strauss GM, Herndon J, Maddaus MA, Johnstone DW, Johnson EA, Watson DM, Sugarbaker DJ, Schilsky RL, Green MR: Randomized Clinical Trial of adjuvant chemotherapy with paclitaxel and carboplatin following resection in Stage IB Non-Small Cell Lung Cancer (NSCLC): Report of Cancer and Leukemia Group B (CALGB) Protocol 9633. ASCO Meeting Abstracts 2004, 22:7019. 13. Strauss GM, Herndon JE, Maddaus MA, Johnstone DW, Johnson EA, Harpole DH, Gillenwater HH, Watson DM, Sugarbaker DJ, Schilsky RL, et al.: Adjuvant paclitaxel plus carboplatin compared with observation in stage IB non-small-cell lung cancer: CALGB 9633 with the Cancer and Leukemia Group B, Radiation Therapy Oncology Group, and North Central Cancer Treatment Group Study Groups. J Clin Oncol 2008, 26:5043–5051.PubMedCrossRef 14. Waller D, Peake MD, Stephens RJ, Gower NH, Milroy R, Parmar MK, Rudd RM, Spiro SG: Chemotherapy for patients with non-small cell lung cancer: the surgical setting of the Big Lung Trial. Eur J Cardiothorac Surg 2004, 26:173–182.PubMedCrossRef 15. Scagliotti GV, Fossati R, Torri V, Crino L, Giaccone G, Silvano G, Martelli M, Clerici M, Cognetti F, Tonato M: Randomized study of adjuvant chemotherapy for completely resected stage I, II, or IIIA non-small-cell Lung cancer. J Natl Cancer Inst 2003, 95:1453–1461.PubMedCrossRef 16.

PubMedCrossRef 34 Chattopadhyay S, Fensterl V, Zhang Y, Veleepar

PubMedCrossRef 34. Chattopadhyay S, Fensterl V, Zhang Y, Veleeparambil M, Yamashita M, Sen GC: Role of interferon regulatory factor 3-mediated apoptosis in the establishment and maintenance of persistent infection by Sendai virus. J Virol 2013, 87:16–24.PubMedCentralPubMedCrossRef

35. Uslu R, Sanli UA, Sezgin C, Karabulut B, Terzioglu E, Omay SB: QNZ solubility dmso arsenic trioxide-mediated cytotoxicity and apoptosis in prostate and ovarian carcinoma cell lines. Clin Cancer Res 2000, 6:4957–4964.PubMed see more 36. Jang M, Kim Y, Won H, Lim S, KRJ , Dashdorj A, Min YH, Kim SY, Shokat KM, Ha J, Kim SS: Carbonyl reductase 1 offers a novel therapeutic target to enhance leukemia treatment by arsenic trioxide. Cancer Res 2012, 72:4214–4224.PubMedCrossRef 37. Chen GQ, Shi XG, Tang W, Xiong SM, Zhu J, Cai X, Han ZG, Ni JH, Shi GY, Jia PM, Liu MM, He KL, Ma J, Zhang P, Zhang TD, Paul P, Naoe T, Kitamura K, Miller W, Waxman S, Wang ZY, de The H, Chen SJ, Chen Z: Use of arsenic trioxide (As 2 O 3 ) in the treatment of acute promyelocytic HDAC phosphorylation leukemia (APL): I. As 2 O 3 exerts dose-dependent dual effects on APL cells. Blood 1997, 89:3345–3353.PubMed 38. Ma DC, Sun YH, Chang KZ, Ma XF, Huang SL, Bai YH, Kang J, Liu YG, Chu JJ: Selective induction of apoptosis of NB4 cells from G2 + M phase by sodium arsenite at lower doses. Eur J Haematol 1998, 61:27–35.PubMedCrossRef 39. Baysan A, Yel L, Gollapudi S, Su H, Gupta S: Arsenic trioxide induces apoptosis via the mitochondrial pathway

by upregulating the expression of Bax and Bim in human B cells. Int J Oncol 2007, 30:313–318.PubMed 40. Kang YH, Lee SJ: The role of p38 MAPK and JNK in arsenic trioxide-induced mitochondrial cell death in human cervical Ribonuclease T1 cancer cells. J Cell Physiol 2008, 217:23–33.PubMedCrossRef 41. Catalani S, Carbonaro V, Palma F, Arshakyan M, Galati R, Nuvoli B, Battistelli S, Canestrari F, Benedetti S: Metabolism modifications and apoptosis induction after Cellfood™ administration to leukemia cell lines. J Exp Clin Cancer Res 2013, 32:63.PubMedCentralPubMedCrossRef 42. Niero EL, Machado-Santelli GM: Cinnamic acid induces apoptotic cell death and cytoskeleton disruption in human

melanoma cells. J Exp Clin Cancer Res 2013, 32:31.PubMedCentralPubMedCrossRef 43. Huang Y, Hu J, Zheng J, Li J, Wei T, Zheng Z, Chen Y: Down-regulation of the PI3K/Akt signaling pathway and induction of apoptosis in CA46 Burkitt lymphoma cells by baicalin. J Exp Clin Cancer Res 2012, 31:48.PubMedCentralPubMedCrossRef 44. Okui T, Fujiwara Y: Inhibition of human excision DNA repair by inorganic arsenic and the comutageniceffect in V79 Chinese hamster cells. Mutat Res 1986, 172:69–76.PubMedCrossRef 45. Kryeziu K, Jungwirth U, Hoda MA, Ferk F, Knasmüller S, Karnthaler-Benbakka C, Kowol CR, Berger W, Heffeter P: Synergistic anticancer activity of arsenic trioxide with erlotinib is based on inhibition of EGFR-mediated DNA double-strand break repair. Mol Cancer Ther 2013, 12:1073–1084.PubMedCrossRef 46.

PubMedCrossRef 46 Hogema BM, Arents JC, Bader R, Eijkemans K, Yo

PubMedCrossRef 46. Hogema BM, Arents JC, Bader R, Eijkemans K, Yoshida H, Takahashi H, Aiba H, Postma PW: Inducer exclusion in Escherichia coli by non-PTS substrates: the role of the PEP to pyruvate ratio in determining the phosphorylation state of enzyme IIA Glc . Mol Microbiol 1998, 30:487–498.PubMedCrossRef 47. Haest CW, de Gier J, van Deenen LL: Changes in the chemical and barrier properties of the membrane lipids of E. coli by variation of the temperature of growth. Chem Phys Lipids 1969, 3:413–417.PubMedCrossRef see more 48. Davies DG, Parsek MR, Pearson JP, Iglewski BH, Costerton JW, Selleckchem P005091 Greenberg EP: The involvement of cell-to-cell signals in the development of a bacterial biofilm. Science 1998, 280:295–298.PubMedCrossRef

49. Otto M: Quorum-sensing

control in Staphylococci – a target for antimicrobial drug therapy? FEMS Microbiol Lett 2004, 241:135–141.PubMedCrossRef 50. Datsenko KA, Wanner BL: One-step inactivation of chromosomal genes in Escherichia coli K-12 using PCR products. Proc Natl Acad Sci USA 2000, 97:6640–6645.PubMedCrossRef 51. Baba T, Ara T, Hasegawa M, Takai Y, Okumura Y, Baba M, Datsenko KA, Tomita M, Wanner BL, Mori H: Construction of Escherichia coli K-12 in-frame, single-gene knockout mutants: the Keio collection. Mol Syst Biol 2006, 2:2006.0008.PubMedCrossRef 52. Walters MC III, Roe F, Bugnicourt A, Franklin MJ, Stewart PS: Contributions of antibiotic penetration, oxygen limitation, and low metabolic activity to tolerance of Pseudomonas aeruginosa biofilms to ciprofloxacin Amylase and tobramycin. Antimicrob Agents Chemother 2003, 47:317–323.PubMedCrossRef 53. Hamilton M: The Biofilm Laboratory Step-By-Step Ganetespib clinical trial Protocols for Experimental Design, Analysis, and Data Interpretation. Edited by: Hamilton M, Heersink J, Buckingham-Meyer K, Goeres D. Cytergy Publishing, Bozeman MT; 2003. 54. Herigstad B, Hamilton M, Heersink J: How to optimize the drop plate method for enumerating bacteria.

J Microbiol Methods 2001, 44:121–129.PubMedCrossRef Authors’ contributions Conception and design of experiment: TRZ, RPC. Acquisition of data: TRZ, HB, JLR, LJT. Analysis and interpretation of data: TRZ, PSS, RPC. Drafting the manuscript: PSS, RPC. Revising the manuscript critically for intellectual content: TRZ, HB, PSS, RPC. Final approval of published version: TRZ, HB, JLR, LJT, PSS, RPC.”
“Background Carbonic anhydrases (CAs, EC 4.2.1.1) are zinc metalloenzymes which catalyze the reversible hydration of carbon dioxide to bicarbonate (CO2 + H2O ↔ HCO3 – + H+). This simple interconversion of a membrane-permeable gas substrate into a membrane-impermeable ionic product is vital to many important biological functions; such enzymes are thus widely distributed in nature. On the basis of differences in amino acid sequence and structure, carbonic anhydrases are divided into five distinct, evolutionarily unrelated gene families: α, β, γ and the recently discovered δ and ζ [1–4].

By exploiting the chemo-enzymatic synthesis

developed by

By exploiting the chemo-enzymatic synthesis

developed by DSM Pharmaceutical Products (Sonke et al., 1999), we prepared enantiomerically pure isovaline and Cα-methylvaline in large amounts. The corresponding AZD8186 mw racemic α-amino amides, synthesized by partial Strecker synthesis, were enzymatically resolved with appropriate α-amino amidases. Then, homo-peptides (di- and tetra-) from the sterically hindered isovaline and Cα-methylvaline were synthesized step-by-step in solution. The highly effective EDC/HOAt or acyl fluoride C-activation procedures RSL3 were employed in peptide bond formation. Results of the catalysis experiments showed Barasertib the all Cα-methylated peptides exhibit significant chiral influence on the synthesis of tetroses

and mimic the effect of the L-Val-L-Val catalyst in having a larger erythrose ee than threose ee, as well as in their configuration relationship with the sugars (the product erythrose acquires ee of configuration opposite to that of the catalyst in case of peptides, while it is the same for amino acids). Interestingly, the largest ee (45% for erythrose) was obtained with the homo-tetrapeptide of isovaline under mild conditions (sodium acetate buffer, pH 5.4, 25°C, 18 h). The homo-dipeptides of both isovaline and Cα-methylvaline also produced a significant ee (41% for erythrose) that appears to increase with time. Because Cα-methylated amino acids are non-racemic in meteorites, do not racemize in aqueous environments, and are known to be (310)-helix (Toniolo and Benedetti, 1991) crotamiton formers in peptides with as few as four residues (Toniolo et al., 2001),

these results suggest that meteoritic, Cα-methylated, α-amino acids may have contributed to molecular evolution upon delivery to the early Earth by catalytically transferring their asymmetry to other prebiotic molecules. Pizzarello, S., Weber, A. (2004). Meteoritic amino acids as asymmetric catalysts. Science, 303:1151. Sonke, T., Kaptein, B., Boesten, W. H. J., Broxterman, Q. B., Schoemaker, H. E., Kamphuis, J., Formaggio, F., Toniolo, C., Rutjes, F. P. J. T. (1999). In Patel, R. N., editor, Stereoselective Biocatalysis, pages 23–58. Dekker, New York, NY. Toniolo, C., Benedetti, E. (1991) The polypeptide 310-helix. Trends Biochem. Sci., 16:350–353. Toniolo, C., Crisma, M., Formaggio, F., Peggion, C. (2001). Control of peptide conformation by the Thorpe-Ingold effect (Cα-tetrasubstitution). Biopolymers (Pept. Sci.), 60:396–419. Weber, A., Pizzarello, S. (2006). The peptide catalyzed stereospecific synthesis of tetroses: a possible model for prebiotic molecular evolution. Proc. Natl.

Such processes can also bring contamination and impurity onto the

Such processes can also bring contamination and impurity onto the area fabricated [13]. In recent decades, the proximal

probe method based on the mechanical stamp and scratching technique has been employed to produce patterned GaAs substrate [4, 14], but it is difficult, if not impossible, to fabricate GaAs nanostructures with low destruction by solely mechanical scratching. Therefore, it is Selleck 3 Methyladenine necessary to develop a straightforward and more flexible fabrication method for the GaAs surface. In the present study, a novel friction-induced micro/nanofabrication method that consists of nanoscratching and post-this website etching was presented to produce nanostructures on GaAs. The effects of the applied normal load and etching period on the formation

of the nanostructure were studied. Based on the X-ray photoelectron spectroscope (XPS) and Raman spectra characterization, the fabrication mechanism of the nanostructure was discussed. Finally, through a homemade multi-probe instrument, Staurosporine clinical trial the capability of this fabrication method was demonstrated by producing various nanostructures on the GaAs surface, such as linear array, intersecting parallel, surface mesas, and special letters. Methods Material The GaAs (100) wafers, n-doped with Si, were purchased from JMEM Electronic Materials, Ltd., Tianjin, China. Using an atomic force microscope (AFM, SPI3800N, Seiko, Tokyo, Japan), the surface root-mean-square (RMS) roughness of the GaAs wafer was measured as 0.5 nm over a 1 μm × 1 μm area. The crystal state of the GaAs material was detected by the X-ray diffraction (XRD, X’Pert, PANalytical, mafosfamide Almelo, Netherlands), showing that the GaAs wafer was single crystal in (100) plane orientation. Before the fabrication, the GaAs wafers were ultrasonically cleaned with methanol and ethanol for 3 min in turn, and successively rinsed with deionized water for 10 min to remove surface contamination. Fabrication method As shown

in Figure 1, the maskless fabrication process consists of scratching and post-etching. When the GaAs surface was scratched by a diamond tip along the designed traces, grooves can be generated on the scanned area. After etching in H2SO4 aqueous solution, different protrusive nanostructures can be produced in situ from the scratched area on the GaAs surface. Scratching tests on the GaAs surface were performed by a nanoscratch tester (CSM Instruments, Peseux, Switzerland) or a homemade multi-probe instrument [15]. The spherical diamond tips used for scratching have the radii of about 5 μm. After the scratching tests, the specimens were dipped in a mixture of H2SO4 aqueous solution (H2SO4/H2O2/H2O = 1:0.5:100) for post-etching [16]. During scratching and post-etching, the experimental temperature was controlled at 22°C and the relative humidity varied between 50% and 55%. All the AFM images of GaAs specimens were scanned by silicon nitride tips (MLCT, Veeco Instruments Inc.

J Phys Chem B 2006,

J Phys Chem B 2006, find more 110:12865–12873.CrossRef 11. Qian F, Li Y, Gradecak S, Park HG, Dong Y, Ding Y, Wang ZL, Lieber CM: Multi-quantum-well nanowire heterostructures for wavelength-controlled

lasers. Nature Mater 2008, 7:701–706.CrossRef 12. Quochi F: Random lasers based on organic epitaxial nanofibers. J Opt 2010, 12:024003.CrossRef 13. Li Y, Dai GZ, Zhou CJ, Zhang QL, Wan Q, Fu LM, Zhang JP, Liu RB, Cao CB, Pan AL, Zhang YH, Zou BS: Formation and optical properties of ZnO:ZnFe 2 O 4 superlattice microwires. Nano Res 2010, 3:326–338.CrossRef 14. Saxena A, Yang SX, Philipose U, Ruda HE: Excitonic and pair-related photoluminescence in ZnSe nanowires. J Appl Phys 2008, 103:053109.CrossRef 15. Vugt LK, Zhang B, Piccione B, Spector AA, Agarwal R: Size-dependent waveguide dispersion in nanowire optical cavities: slowed light and dispersionless guiding. Nano Lett 2009, 9:1684–1688.CrossRef 16. Zhou WC, Liu RB, Tang DS, Wang XX, Fan HM, Pan AL, Zhang QL, Wan Q, Zou BS: Luminescence and local photonic confinement of single ZnSe:Mn nanostructure and the shape dependent lasing behavior. Nanotechnology 2013, 24:055201.CrossRef 17. Lee JY, Kim DS, Kang JH, Yoon SW, Lee H, Park J: Novel Zn 1- x Mn x Se ( x =0.1–0.4) one-dimensional nanostructures: nanowires, zigzagged nanobelts, and toothed nanosaws. J Phys Chem B 2006, 110:25869–25874.CrossRef 18. Kang JW, Choi YS, Choe

M, Kim NY, Lee T, Kim BJ, Tu CW, Park SJ: Electrical and structural properties of antimony-doped p-type Belnacasan solubility dmso ZnO nanorods with self-corrugated surfaces. Nanotechnology 2012, 23:495712.CrossRef 19. Suh M, Meyyappan M, Ju S: The effect of Ga content on In 2x Ga 2–2 x O 3 nanowire transistor characteristics. Nanotechnology 2012, 23:305203.CrossRef 20. Wang FF, Zhang ZH, Liu RB, Wang X, Zhu X, Pan AL, Zou BS: Structure and stimulated emission of ZnSe nanoribbons grown by thermal evaporation. Nanotechnology 2007, 18:305705.CrossRef 21. Popović ZV, Milutinović A: Far-infrared reflectivity and

Raman scattering study of α -MnSe. Phys Rev B 2006, 73:155203.CrossRef 22. Jiang Y, Meng XM, Yiu WC, Liu J, Ding JX, Lee CS, Lee ST: Zinc selenide nanoribbons and nanowires. J Phys Chem B 2004, 108:2784–2787.CrossRef 23. Leung YP, AZD6738 clinical trial Wallace Verteporfin price CHC, Markov I, Pang GKH, Ong HC, Yuk TI: Synthesis of wurtzite ZnSe nanorings by thermal evaporation. Appl Phys Lett 2006, 88:183110.CrossRef 24. Philipose U, Xu T, Yang S, Sun P, Ruda HE, Wang YQ, Kavanagh KL: Enhancement of band edge luminescence in ZnSe nanowires. J Appl Phys 2006, 100:084316.CrossRef 25. Panda AB, Acharya S, Efrima S: Ultranarrow ZnSe nanorods and nanowires: structure, spectroscopy, and one-dimensional properties. Adv Mater 2005, 17:2471–2474.CrossRef 26. Na CW, Han DS, Kim DS, Kang YJ, Lee JY, Park J, Oh DK, Kim KS, Kim D: Photoluminescence of Cd 1- x Mn x S ( x ≤0.3) nanowires. J Phys Chem B 2006, 110:6699–6704.CrossRef 27.