Monitoring of Eschericia. Coli O157 From Raw Cow\u27s Milk in the Storage Tank in Sleman District, YOGYAKARTA

Escherichia coli O157 is a member of Enterobacteriaceae which has somatic antigen O157. E. coli O157 isassociated with life threatening diseases such as hemorrhagic colitis (HC), hemolytic uremic syndrome(HUS) and thrombotic thrombocytopenic purpura (TTP). Raw milk is considered a high risk food as it ishighly nutritious and serves as an ideal medium for bacterial growth. The aim of this study was to monitorE. coli O157 contamination in the storage tank before distribution in Sleman district, Yogyakarta. Totalof 30 raw milk samples were collected from the storage tank in Sleman district. Tryptic Soy Broth (TSB)media added with novobiocin was used as enrichment medium, while Chromocult Coliform Agar (CCA)and Chromagar O157 medium for screening test. Additional analysis including serologic and moleculartest of isolates obtained. Based on the screening result, 11,428 colonies were considered as E. coli O157 suspectthat produced red colour in CCA medium. Further screening employing Chromagar O157 mediumresulted in 3 potential colonies which produce mauve colour. These colonies were later tested with LatexTest O157 for serological reason, showing that none were E. coli O157. Molecular analysis with primer pairsfor detection of Stx1 and Stx2 genes confirm that none of the suspected strains have genes that encodedthe toxin, Stx1 and Stx2. These results showed that the presence of STEC (Shiga toxin E. coli) hasn\u27t foundin the tested samples of raw cow\u27s milk

Three-dimensional optoacoustic imaging of nailfold capillaries in systemic sclerosis and its potential for disease differentiation using deep learning

From Springer Nature via Jisc Publications RouterHistory: received 2020-05-07, accepted 2020-09-09, registration 2020-09-16, pub-electronic 2020-10-05, online 2020-10-05, collection 2020-12Publication status: PublishedFunder: Helmholtz Association; doi: http://dx.doi.org/10.13039/501100009318; Grant(s): i3 (ExNet-0022-Phase2-3)Funder: University of Manchester; doi: http://dx.doi.org/10.13039/501100000770; Grant(s): MC_PC_16053Funder: Manchester Biomedical Research Centre; doi: http://dx.doi.org/10.13039/100014653Funder: H2020 European Research Council; doi: http://dx.doi.org/10.13039/100010663; Grant(s): No 694968 (PREMSOT)Funder: Arthritis Research UK,United Kingdom; Grant(s): 19465Abstract: The autoimmune disease systemic sclerosis (SSc) causes microvascular changes that can be easily observed cutaneously at the finger nailfold. Optoacoustic imaging (OAI), a combination of optical and ultrasound imaging, specifically raster-scanning optoacoustic mesoscopy (RSOM), offers a non-invasive high-resolution 3D visualization of capillaries allowing for a better view of microvascular changes and an extraction of volumetric measures. In this study, nailfold capillaries of patients with SSc and healthy controls are imaged and compared with each other for the first time using OAI. The nailfolds of 23 patients with SSc and 19 controls were imaged using RSOM. The acquired images were qualitatively compared to images from state-of-the-art imaging tools for SSc, dermoscopy and high magnification capillaroscopy. The vascular volume in the nailfold capillaries were computed from the RSOM images. The vascular volumes differ significantly between both cohorts (0.216 ± 0.085 mm3 and 0.337 ± 0.110 mm3; p < 0.0005). In addition, an artificial neural network was trained to automatically differentiate nailfold images from both cohorts to further assess whether OAI is sensitive enough to visualize anatomical differences in the capillaries between the two cohorts. Using transfer learning, the model classifies images with an area under the ROC curve of 0.897, and a sensitivity of 0.783 and specificity of 0.895. In conclusion, this study demonstrates the capabilities of RSOM as an imaging tool for SSc and establishes it as a modality that facilitates more in-depth studies into the disease mechanisms and progression

Genetic Evidence for a Tight Cooperation of TatB and TatC during Productive Recognition of Twin-Arginine (Tat) Signal Peptides in Escherichia coli

The twin arginine translocation (Tat) pathway transports folded proteins across the cytoplasmic membrane of bacteria. Tat signal peptides contain a consensus motif (S/T-R-R-X-F-L-K) that is thought to play a crucial role in substrate recognition by the Tat translocase. Replacement of the phenylalanine at the +2 consensus position in the signal peptide of a Tat-specific reporter protein (TorA-MalE) by aspartate blocked export of the corresponding TorA(D+2)-MalE precursor, indicating that this mutation prevents a productive binding of the TorA(D+2) signal peptide to the Tat translocase. Mutations were identified in the extreme amino-terminal regions of TatB and TatC that synergistically suppressed the export defect of TorA(D+2)-MalE when present in pairwise or triple combinations. The observed synergistic suppression activities were even more pronounced in the restoration of membrane translocation of another export-defective precursor, TorA(KQ)-MalE, in which the conserved twin arginine residues had been replaced by lysine-glutamine. Collectively, these findings indicate that the extreme amino-terminal regions of TatB and TatC cooperate tightly during recognition and productive binding of Tat-dependent precursor proteins and, furthermore, that TatB and TatC are both involved in the formation of a specific signal peptide binding site that reaches out as far as the end of the TatB transmembrane segment

The Dictyostelium discoideum acaA Gene Is Transcribed from Alternative Promoters during Aggregation and Multicellular Development

Background: Extracellular cAMP is a key extracellular signaling molecule that regulates aggregation, cell differentiation and morphogenesis during multi-cellular development of the social amoeba Dictyostelium discoideum. This molecule is produced by three different adenylyl cyclases, encoded by the genes acaA, acrA and acgA, expressed at different stages of development and in different structures. Methodology/Principal Findings: This article describes the characterization of the promoter region of the acaA gene, showing that it is transcribed from three different alternative promoters. The distal promoter, promoter 1, is active during the aggregation process while the more proximal promoters are active in tip-organiser and posterior regions of the structures. A DNA fragment containing the three promoters drove expression to these same regions and similar results were obtained by in situ hybridization. Analyses of mRNA expression by quantitative RT-PCR with specific primers for each of the three transcripts also demonstrated their different temporal patterns of expression. Conclusions/Significance: The existence of an aggregation-specific promoter can be associated with the use of cAMP as chemo-attractant molecule, which is specific for some Dictyostelium species. Expression at late developmental stages indicates that adenylyl cyclase A might play a more important role in post-aggregative development than previously considered

The Hydrophobic Core of Twin-Arginine Signal Sequences Orchestrates Specific Binding to Tat-Pathway Related Chaperones

Redox enzyme maturation proteins (REMPs) bind pre-proteins destined for translocation across the bacterial cytoplasmic membrane via the twin-arginine translocation system and enable the enzymatic incorporation of complex cofactors. Most REMPs recognize one specific pre-protein. The recognition site usually resides in the N-terminal signal sequence. REMP binding protects signal peptides against degradation by proteases. REMPs are also believed to prevent binding of immature pre-proteins to the translocon. The main aim of this work was to better understand the interaction between REMPs and substrate signal sequences. Two REMPs were investigated: DmsD (specific for dimethylsulfoxide reductase, DmsA) and TorD (specific for trimethylamine N-oxide reductase, TorA). Green fluorescent protein (GFP) was genetically fused behind the signal sequences of TorA and DmsA. This ensures native behavior of the respective signal sequence and excludes any effects mediated by the mature domain of the pre-protein. Surface plasmon resonance analysis revealed that these chimeric pre-proteins specifically bind to the cognate REMP. Furthermore, the region of the signal sequence that is responsible for specific binding to the corresponding REMP was identified by creating region-swapped chimeric signal sequences, containing parts of both the TorA and DmsA signal sequences. Surprisingly, specificity is not encoded in the highly variable positively charged N-terminal region of the signal sequence, but in the more similar hydrophobic C-terminal parts. Interestingly, binding of DmsD to its model substrate reduced membrane binding of the pre-protein. This property could link REMP-signal peptide binding to its reported proofreading function