E ND AA L . 1999. Lactobacillus pentosus TV35b, isolated from the posterior fornix secretions of the vagina of a prenatal patient, produced a bacteriocin-like peptide (pentocin TV35b), which is inhibitory to Clostridium sporogenes, Cl. tyrobutyricum, Lact. curvatus, Lact. fermentum, Lact. sake, Listeria innocua, Propionibacterium acidipropionici, Propionibacterium sp. and Candida albicans. The mechanism of activity of pentocin TV35b is bactericidal, as shown by a decrease in the viable cell numbers of Lact. sake from approximately 4 × 10 8 to less than 10 cfu ml −1 over a period of 4 h. Pentocin TV35b added to the growth medium of C. albicans stimulated the formation of pseudohyphae during the first 36 h, followed by a slight repression in cell growth. Production of pentocin TV35b was at its maximum towards the end of the logarithmic growth phase of strain TV35b. The peptide was purified by ammonium sulphate precipitation, followed by SP-Sepharose cation exchange chromatography. The molecular size of pentocin TV35b was estimated to be between 2·35 and 3·4 kDa, according to tricine-SDS PAGE. However, results obtained by electrospray ionization mass spectroscopy indicated that the peptide is 3930·2 Da in size. Amino acid analysis performed by using the Pico-Tag® method and a Nova-Pak C 18 HPLC column indicated that pentocin TV35b consists of 33 amino acids with a total mass of 3929·63 Da. Pentocin TV35b is inactivated when treated with papain and Proteinase K, but remains active after incubation at pH 1-10 for 2 h at 25°C, and when heattreated for 30 min at 100°C.
Background: Within the last decade, below the giant dipole resonance the existence of a concentration of additional electric dipole strength has been established. This accumulation of low-lying E1 strength is commonly referred to as pygmy dipole resonance (PDR). Purpose: The photoresponse of 60 Ni has been investigated experimentally and theoretically to test the evolution of the PDR in a nucleus with only a small neutron excess. Furthermore, the isoscalar and isovector M1 resonances were investigated. Method: Spin-1 states were excited by exploiting the (γ, γ ) nuclear resonance fluorescence technique with unpolarized continuous bremsstrahlung as well as with fully linearly polarized, quasimonochromatic, Comptonbackscattered laser photons in the entrance channel of the reaction. Results: Up to 10 MeV a detailed picture of J = 1 levels was obtained. For the preponderant number of the individual levels spin and parity were firmly assigned. Furthermore, branching ratios, transition widths, and reduced B(E1) or B(M1) excitation probability were calculated from the measured scattering cross sections. A comparison with theoretical results obtained within the quasiparticle phonon model allows an insight into the microscopic structure of the observed states. Conclusions: Below 10 MeV the directly observed E1 strength [ B(E1) ↑= (153.8 ± 9.5) e 2 (fm) 2 ] exhausts 0.5% of the Thomas-Reiche-Kuhn sum rule. This value increases to 0.8% of the sum rule [ B(E1) ↑= (250.9 ± 31.1) e 2 (fm) 2 ] when indirectly observed branches to lower-lying levels are considered. Two accumulations of M1 excited spin-1 states near 8 and 9 MeV excitation energy are identified as isoscalar and isovector M1 resonances dominated by proton and neutron f 7/2 → f 5/2 spin-flip excitations. The B(M1) ↑ strength of these structures accumulates to 3.94(27)μ 2 N .
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