Transcriptome and proteome analyses of adaptive responses to methyl methanesulfonate in Escherichia coli K-12 and ada mutant strains

<p>Abstract</p> <p>Background</p> <p>The Ada-dependent adaptive response system in <it>Escherichia coli </it>is important for increasing resistance to alkylation damage. However, the global transcriptional and translational changes during this response have not been reported. Here we present time-dependent global gene and protein expression profiles following treatment with methyl methanesulfonate (MMS) in <it>E. coli </it>W3110 and its <it>ada </it>mutant strains.</p> <p>Results</p> <p>Transcriptome profiling showed that 1138 and 2177 genes were differentially expressed in response to MMS treatment in the wild-type and mutant strains, respectively. A total of 81 protein spots representing 76 nonredundant proteins differentially expressed were identified using 2-DE and LC-MS/MS. In the wild-type strain, many genes were differentially expressed upon long-exposure to MMS, due to both adaptive responses and stationary phase responses. In the <it>ada </it>mutant strain, the genes involved in DNA replication, recombination, modification and repair were up-regulated 0.5 h after MMS treatment, indicating its connection to the SOS and other DNA repair systems. Interestingly, expression of the genes involved in flagellar biosynthesis, chemotaxis, and two-component regulatory systems related to drug or antibiotic resistance, was found to be controlled by Ada.</p> <p>Conclusion</p> <p>These results show in detail the regulatory components and pathways controlling adaptive response and how the related genes including the Ada regulon are expressed with this response.</p

Proteome-Level Responses of Escherichia coli to Long-Chain Fatty Acids and Use of Fatty Acid Inducible Promoter in Protein Production

In Escherichia coli, a long-chain acyl-CoA is a regulatory signal that modulates gene expression through its binding to a transcription factor FadR. In this study, comparative proteomic analysis of E. coli in the presence of glucose and oleic acid was performed to understand cell physiology in response to oleic acid. Among total of 52 proteins showing altered expression levels with oleic acid presence, 9 proteins including AldA, Cdd, FadA, FadB, FadL, MalE, RbsB, Udp, and YccU were newly synthesized. Among the genes that were induced by oleic acid, the promoter of the aldA gene was used for the production of a green fluorescent protein (GFP). Analysis of fluorescence intensities and confocal microscopic images revealed that soluble GFP was highly expressed under the control of the aldA promoter. These results suggest that proteomics is playing an important role not only in biological research but also in various biotechnological applications

Congenital Heart Disease (Atrioventricular Septal Defect) in the Mouse with Trisomy 16

Failure of fusion between the superior and inferior cushions has usually been assumed to be the main morphogenetic event in producing hearts with deficient atrioventricular septation (atrioventricular septal, or endocardial cushion defects). Morphological studies on human autopsy specimens, however, showed that another consistent finding is the marked disproportion between the dimensions of the inlet and outlet of the left ventricle, which, until now, has no known developmental basis. We have studied the early formation of the hearts with atrioventricular septal defects, using a mouse model with trisomy 16. Animals were studied between the 10th and 19th days of gestation by stereomicroscopic examination, scanning electronmlcroscopy and the in-vitro incorporation of thymidine. The first detectable morphological abnormality of the heart in the trisomic mouse was observed on the 11th day, being a persistence of an infolding at the inferior atrioventricular junction. This infolding was present in both trisomic and eusomic animals on the 10th day. This morphology could be explained by a differential growth of the myocardium at the inferior atrioventricular junction, which was found to be a distinct zone with low incorporation of thymidine. On the 11th day, the inferior atrioventricular cushion was bigger in the trisomic hearts. The abnormalities of the cushions observed on the 12th day or later were deemed to be consequences of these primary defects. Sectioning of the heart from the left lateral aspect convincingly showed morphological changes of the superior and inferior cushion or bridging leaflets in this animal model. Abnormal endocardial cushions and abnormality in the proliferation index of the myocardium at the inferior atrioventricular junction play more significant roles in the formation of the hearts with deficient atrioventricular septation, than the abnormalities found in the atrioventricular cushions

X-chromosome Inactivation Patterns in Korean Women with Idiopathic Recurrent Spontaneous Abortion

Recurrent spontaneous abortion (RSA) defines as two or more consecutive losses at ≤20 weeks of gestation and affects an estimated 1 of every 100 couples wishing to have children. However, it remains a poorly understood phenomenon. Recent reports observed a significant association between highly skewed X chromosome and RSA, supporting that X chromosome inactivation might be an important and previously unknown cause of RSA. X-inactivation pattern, using polymeric X-linked women with idiopathic RSA and 80 control subjects with a single successful pregnancy and no history of spontaneous abortion. The ratio of heterozygotes was 68.2% (45/66) in women with RSA and 67.5% (54/80) in control group. Among 45 informative RSA cases, only 1 (2.2%) woman showed extreme skewed X inactivation (≥90%) and 4 (8.9%) had mild skewed inactivation (≥85%). In 54 heterozygous control subjects, 5 (9.3%) women showed extreme skewed X inactivation and 7 (13.0%) had mild one. The frequency of skewed X inactivation between RSA patients and control group was not significantly different (p>0.05). This finding suggests that skewed X chromosome be not associated with unexplained RSA patients

Isolated Weakness of Middle, Ring, and Little Fingers due to a Small Cortical Infarction in the Medial Precentral Gyrus

Small cortical strokes can produce predominant isolated weakness in a particular group of fingers: radial or ulnar. The traditional views are of point-to-point representations of each finger to neurons located in the precentral gyrus of the motor cortex such that the neurons of the radial fingers are located laterally and those of the ulnar fingers are located medially. We present a case of isolated weakness of middle, ring, and little fingers due to a small cortical infarction in the medial precentral gyrus