Mitochondrial modulation of apoptosis induced by low-dose radiation in mouse testicular cells / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To investigate whether apoptosis induced by low-dose radiation (LDR) is regulated by mitochondrial pathways in testicular cells.</p><p><b>METHODS</b>Male mice were exposed to whole-body LDR, and changes in mitochondrial function and in expression of apoptotic factors were analyzed in the testicular cells as follows. Total nitric-oxide synthase (T-NOS) and Na+/K+ ATPase activities were biochemically assayed. Reactive oxygen species (ROS) and mitochondrial membrane potential (Δψm) were determined by flow cytometry using fluorescent probes. Levels of mRNAs encoding cytochrome c (Cyt c) and apoptosis-inducing factor (AIF) were quantified by real-time reverse-transcription PCR (RT-PCR). Expression of Cyt c, AIF, caspase-9, and caspase-3 at the protein level was assessed by western blotting and immunohistochemistry.</p><p><b>RESULTS</b>LDR induced an increase in T-NOS activity and ROS levels, and a decrease in Na+/K+ ATPase activity and mitochondrial Δψm, in the testicular cells. The intensity of these effects increased with time after irradiation and with dose. The cells showed remarkable swelling and vacuolization of mitochondria, and displayed a time- and dose-dependent increase in the expression of Cyt c, AIF, procaspase-9, and procaspase-3. Activation of the two procaspases was confirmed by detection of the cleaved caspases. The changes in expression of the four apoptotic factors were mostly limited to spermatogonia and spermatocytes.</p><p><b>CONCLUSION</b>LDR can induce testicular cell apoptosis through mitochondrial signaling pathways.</p>

Cellular fatty acids as chemical markers for differentiation of Acinetobacter baumannii and Acinetobacter calcoaceticus / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>Gas chromatography (GC) was used to investigate the cellular fatty acid (CFA) composition of 141 Acinetobacter baumannii and 32 A. calcoaceticus isolates from different locations in China and to find chemical markers to differentiate these two closely related bacteria.</p><p><b>METHODS</b>Whole cell fatty acid methyl esters (FAMEs) were obtained by saponification, methylation, and extraction for GC analysis, followed by a standardized Microbial Identification System (MIS) analysis.</p><p><b>RESULTS</b>All A. baumannii and A. calcoaceticus strains contained some major fatty acids, namely, 18:1 ω9c, 16:0, Sum In Feature 3, 12:0, 17:1ω8c, 3-OH-12:0, 17:0, Sum In Feature 2, 2-OH-12:0, and 18:0 compounds. Although most of the total CFAs are similar between A. baumannii and A. calcoaceticus strains, the ratios of two pairs of CFAs, i.e., Sum In Feature 3/18:1 ω9c versus 16:0/18:1 ω9c and Sum In Feature 3/18:1 ω9c versus unknown 12.484/18:1 ω9c fatty acids, could differentiate these two closely related bacteria. A. baumannii could be easily classified into two subgroups by plotting some ratios such as Sum In Feature 3/16:0 versus 17:0 and Sum In Feature 3/2-OH-12:0 versus 17:0 fatty acids.</p><p><b>CONCLUSION</b>The ratios of some CFAs could be used as chemical markers to distinguish A. baumannii from A. calcoaceticus.</p>