Fig. 6 Tom and Hope Punnett, Philadelphia PA, 2007 Acknowledgment We thank George C. Papageorgiou, who knew several members of the

Emerson-Rabinowitch Photosynthesis Project, for his valuable suggestions, and for editing the final copy of this manuscript. George was our guest editor, who enthusiastically recommended acceptance of this Tribute for publication in Photosynthesis Research. References Bannister TT (1972) The careers and contributions of Eugene Rabinowitch. Biophy J 12:707–HTS assay 718CrossRef Bonaventura C, Myers J (1969) Fluorescence and oxygen evolution from Chlorella pyrenoidosa. Biochim Biophys Acta 89:366–383 Brody SS (1992) We remember Eugene [Rabinowitch] and his lab during the fifties. Photosynth Res 43:67–74CrossRef Emerson R, Lewis

CM (1943) The dependence of MK 8931 mouse the MEK inhibitor quantum yield of Chlorella photosynthesis on wavelength of light. Am J Bot 30:165–178CrossRef Emerson R, Chalmers RV, Cederstrand CN (1957) Some factors influencing the long wave limit of photosynthesis. Proc Natl Acad Sci USA 43:133–143PubMedCrossRef Ghosh AK (2004) Passage of a young Indian physical chemist through the world of photosynthesis research at Urbana, Illinois in the 1960s: a personal essay. Photosynth Res 80:427–437PubMedCrossRef Govindjee, Krogmann D (2004) Discoveries in oxygenic photosynthesis (1727–2003): a perspective: dedicated to the memories of Martin Kamen (1920–2002), William A. Arnold 1904–2001). Photosynth Res 80:15–57PubMedCrossRef Govindjee, Rabinowitch E (1960) Two forms of chlorophyll a in vivo with distinct photochemical functions. Science 132:159–160 Govindjee, van Rensen JJS (1978) Bicarbonate effects on the electron flow in isolated broken chloroplasts. Biochim Biophys Acta 505:183–213 Govindjee R, Govindjee, Hoch G (1964) Emerson enhancement effect in chloroplast reactions. Plant Physiol 39:10–14PubMedCrossRef

Hagar W, Punnett T (1973) Probit transformation: improved method for defining synchrony of cell cultures. Science 182:1028–1030PubMedCrossRef Hill R (1937) Oxygen evolution by isolated chloroplasts. Nature 139:881–882CrossRef Low-density-lipoprotein receptor kinase Hill R (1939) Oxygen produced by isolated chloroplasts. Proc R Soc Lond Ser B 127:192–210CrossRef Hirsch RE, Rich M, Govindjee (2010) A tribute to Seymour Steven Brody: in memoriam (November 29, 1927 to May 25, 2010). Photosynth Res 106:191–199PubMedCrossRef Murata N (1969) Control of excitation transfer in photosynthesis. I. Light-induced changes of chlorophyll a fluorescence in Porphyridium cruentum. Biochim Biophys Acta 172:242–251PubMedCrossRef Myers J, French CS (1960) Evidences from action spectra for a specific participation of chlorophyll b in photosynthesis. J Gen Physiol 43:723–736PubMedCrossRef Papageorgiou GC, Govindjee (2011) Photosystem II fluorescence: slow changes-scaling from the past.

The AuNPs prepared with PBHs containing Met residue were stabilised with a lower number of ligands on each AuNP surface compared to the AuNPs capped with other PBH ligands. A direct comparison of Au[(Met)2B] and Au[(TrCys)2B] revealed fewer ligands for the Met-containing PBH-AuNP, despite both having the same diameter. 1H NMR spectra and FT-IR absorption spectra of free PBHs and of the PBH-capped AuNPs were measured to identify the interactions between the gold

surface and the capping ligand. The NMR spectra of the AuNPs showed broad signals PF-02341066 clinical trial compared to the free PBHs. Figure 3 shows 1H NMR spectra of Au[(Gly-Tyr-Met)2B] and its free PBH (Gly-Tyr-Met)2B in DMSO-d 6. The signal of the H-α of the Met residue appeared at approximately 1.5 ppm in the PBH (Gly-Tyr-Met)2B NMR spectrum and was significantly broadened in that

of Au[(Gly-Tyr-Met)2B]. A similar line broadening was also BAY 73-4506 observed in the NMR spectrum of Au[(Gly-Trp-Met)2B] (Figure 3) and of Au[(Met)2B] (see Additional file 2: Figure S1). These observations indicate that the PBH was attached to the gold surface through the Met residue [46]. Analogous results were observed for the NMR spectra of Au[(Gly-Tyr-TrCys)2B] and Au[(TrCys)2B] [9], where the sulphur atom of the TrCys residue is see more involved in the surface binding. Figure 3 1 H NMR spectra of Epothilone B (EPO906, Patupilone) free PBHs and PBH-capped AuNPs. (a) Free PBH (Gly-Tyr-Met)2B (top) and 1H NMR spectrum of AuNP Au[(Gly-Tyr-Met)2B] (bottom) in DMSO-d6, and (b) 1H NMR spectrum of free PBH (Gly-Trp-Met)2B (top)

and 1H NMR spectrum of AuNP Au[(Gly-Trp-Met)2B] (bottom) in DMSO-d6. Table 1 Structural characteristics of the AuNPs from elemental analysis and TEM data AuNP Size (nm) Calculated m/na from %Nb Number of Au atomsc PBH units per Au nanoparticle Mw Au[(Gly-Trp-Met)2B] 1.6 0.062 126 8 32,106 Au[(Gly-Tyr-TrCys) 2 B] 1.8 0.22 180 40 90,397 Au[(Gly-Tyr-Met)2B] 1.5 0.064 104 7 27,100 Au[(Met)2B] 2.3 0.154 375 57 102,625 Au[(TrCys)2B] 2.3 0.26 375 97 164,377 Bold emphasis is used to signal the most stable AuNP; a m, Number of PBH units; n, Number of Au atoms; b%N from elemental analysis; cestimated supposing spherical particles and applying N = 30.89602 D3 [47]. The FT-IR spectra are shown in Figure 4. For Au[(Gly-Tyr-Met)2B], Au[(Gly-Trp-Met)2B] and Au[(Met)2B], the band caused by the C = O stretching mode of the carboxylic group was absent. However, two bands were observed around 1,600 and 1,398 cm−1, assigned to the asymmetric and symmetric stretching vibrations of carboxylate anions [48]. These results suggest that the carboxylic groups are also involved in PBH interactions with the gold surface. Significant changes were observed in the amide I band in the spectra of capped NPs compared with those of the free PBHs.

Alternatively, loss of defense against H. pylori may be due to loss of antibacterial function of LL-37 in the milieu of the gastric mucosa. Consequently, design of antimicrobial agents that are more effective in this setting can be beneficial. Motivated by immunohistological results, the activity of LL-37 against clinical isolates of H. pylori and E. coli MG1655 under biologically relevant conditions was compared with that of the

synthetic peptide WLBU2 and the ceragenin CSA-13. This study shows that CSA-13, contrary to LL-37 and WLBU2 peptides, maintains strong bactericidal activity in the presence of mucin and after preincubation with pepsin at low pH. These conditions represent unique challenges related to H. pylori treatment, as these bacteria in the stomach are protected from the Veliparib manufacturer acidic environment by a thick mucus layer and the effectiveness of many antimicrobial drugs is greatly diminished at acidic pH [31]. Accordingly, the first effective therapy for H. pylori infection was a combination of relatively pH-insensitive antimicrobial drugs such as bismuth, tetracycline and metronidazole [33]. In addition, as the stomach periodically

empties its contents (topical therapy tends to be diluted and washed Selleck FRAX597 out) the finding that CSA-13 has bactericidal activity at much lower concentration then LL-37, after the same incubation time (3-6 hours) [11], suggests that CSA-13 may have therapeutic potential for treatment of H. pylori infection. The antibacterial activity of CSA-13, which has a smaller net charge and a unique distribution of this charge over a steroid scaffold when compared with LL-37 and WLBU2 peptides, was also found to be less inhibited by mucin isolated from gastric mucosa. Therapeutic potential based on the ability of CSA-13 to eradicate H. pylori is also supported by previously reported antibacterial activity against other bacteria strains, including clinical

isolates of Pseudomonas aeruginosa [21] and S. aureus [22]. CSA-13′s unique ability to compromise bacterial membrane integrity and the chemical nature of this low-molecular-mass Tyrosine-protein kinase BLK compound that translates to lower cost of synthesis compared to cationic antibacterial peptides suggest that CSA-13 or perhaps other ceragenins have potential for treatment of H. pylori infection, including those caused by its selleck chemical resistant strains. Conclusion Bactericidal activity of ceragenin CSA-13 is maintained after preincubation in simulated gastric juice and in the presence of mucin. This in vitro evaluation indicates a significant potential of this molecule in treatment of stomach mucosal infection.