http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Macrolide Resistance and In Vitro Selection of Resistance to Antibiotics in Lactobacillus Isolates
Lorenzo Drago,Roberto Mattina,Lucia Nicola,Valentina Rodighiero,Elena De Vecchi 한국미생물학회 2011 The journal of microbiology Vol.49 No.4
Spreading of resistance to antibiotics is of great concern due to the increasing rate of isolation of multiresistant pathogens. Since commensal bacteria may transfer determinants of resistance to pathogens, studies on development of resistance should include also lactobacilli. Resistance to macrolides, penicillins and tetracycline was determined in 40 isolates of Lactobacillus acidophilus, Lactobacillus plantarum, Lactobacillus crispatus,and Lactobacillus casei isolated from faeces of apparently healthy volunteers. Frequency of mutation and changes in susceptibility after serial exposure to these antibiotics at concentrations of 4× and 8× MIC were evaluated in susceptible isolates. Acquired resistance was defined as an increment in MIC values of at least four times in respect to the pre-selection values. Resistance to macrolides and/or tetracycline was identified in 14 and 4 isolates, respectively. ermB gene and A2058G mutation in 23S rRNA were detected in macrolide resistant isolates. Frequencies of mutation of susceptible isolates (n=26) were lower for ampicillin and erythromycin than for tetracycline. Serial exposure to antibiotics led to selection of resistant mutants. However,acquired resistance was rather unstable and was lost after subcultures in antibiotic-free medium in most mutants. Resistance to erythromycin was associated to a A2058G mutation in 23S rRNA. In conclusion,results indicate that resistance to macrolides and tetracycline is present among intestinal lactobacilli. Decrease in susceptibility following serial exposure to antibiotics might occur in lactobacilli, in a strain- and antibiotic-dependent way. Since lactobacilli are often used as probiotics, their ability to acquire resistance should be evaluated for isolates candidate to be included in probiotics based products.
AKARI-NEP : EFFECTS OF AGN PRESENCE ON SFR ESTIMATES OF GALAXIES
L. Marchetti,A. Feltre,S. Berta,I. Baronchelli,S. Serjeant,M. Vaccari,D. Bulgarella,M.Karouzos,K. Murata,N.Oi,C. Pearson,G. Rodighiero,C. Segdwick,G. J. White 한국천문학회 2017 天文學論叢 Vol.32 No.1
How does the presence of an AGN influence the total SFR estimates of galaxies and change their distribution with respect to the \textit{Galaxy Main Sequence}?To contribute to solving this question, we study a sample of 1133 sources detected in the North Ecliptic Pole field (NEP) by AKARI and Herschel. We create a multi-wavelength dataset for these galaxies and we fit their multi-wavelength Spectral Energy Distribution (SED) using the whole spectral regime (from 0.1 to 500 $\mu$m). We perform the fit using three procedures: \texttt{LePhare} and two optimised codes for identifying AGN tracers from the SED analysis. In this work we present an overview of the comparison between the estimates of the Infrared bolometric luminosities (between 8 and 1000 $\mu$m) and the AGN fractions obtained exploiting these different procedures. In particular, by estimating the AGN contribution in four different wavelength ranges (5-40 $\mu$m, 10-20 $\mu$m, 20-40 $\mu$m and 8-1000 $\mu$m) we show how the presence of an AGN affects the PAH emission by suppressing the ratio $\frac{L_{\rm8~\mu m}}{L_{\rm4.5~\mu m}}$ as a function of the considered wavelength range.
AKARI DEEP FIELD SOUTH: SPECTROSCOPIC OBSERVATIONS OF INFRARED SOURCES
Chris Sedgwick,STEPHEN SERJEANT,CHRIS PEARSON,Shuji Matsuura,MAI SHIRAHATA,Hideo Matsuhara,Lucia Marchetti,Glenn J. White,Mattia Vaccari,Ivano Baronchelli,Giulia Rodighiero,Bunyo Hadsukade,David L. Cl 한국천문학회 2017 天文學論叢 Vol.32 No.1
We present a summary of our spectroscopic redshift catalogue of 404 sources in the {\it AKARI} Deep Field South (ADF-S). We have used the AAOmega spectrograph to target mid-infrared and far-infrared sources selected primarily from {\it AKARI} observations in this field for which we were able to obtain optical counterparts. Our sources with identified redshifts include 316 with H$\alpha$ detections at z ≤ 0.345 and 15 sources at z > 1 with MgII or Lyα emission lines. About 13% of our z ≤0.345 sources are dominated by active galactic nuclei (AGN) emission, although many show emission from both star formation and AGNs. The median Balmer decrement is 5.9. Ultra-luminous infrared galaxies (ULIRGs) were found only in the higher-redshift sources. Optical and near infrared data will be available shortly, enabling calibration of the line luminosities and spectral energy distribution (SED) fitting for these sources.