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We report a case of a 30 year old gentleman seen on the respiratory ward with no significant past medical history presenting with a three week history of worsening dyspnoea, productive cough, fever, bilateral leg swelling and bilateral leg swelling. Initial differential diagnosis included community-acquired pneumonia, cellulitis and deep vein thrombosis. After much investigation a diagnosis of AIDS-related kaposi's sarcoma with visceral manifestations was made.

Background: Analysis of large datasets produced by mass spectrometry-based proteomics relies on database search algorithms to sequence peptides and identify proteins. Several such scoring methods are available, each based on different statistical foundations and thereby not producing identical results. Here, the aim is to compare peptide and protein identifications using multiple search engines and examine the additional proteins gained by increasing the number of technical replicate analyses.

Methods: A HeLa whole cell lysate was analyzed on an Orbitrap mass spectrometer for 10 technical replicates. The data were combined and searched using Mascot, SEQUEST, and Andromeda. Comparisons were made of peptide and protein identifications among the search engines. In addition, searches using each engine were performed with incrementing number of technical replicates.

Results: The number and identity of peptides and proteins differed across search engines. For all three search engines, the differences in proteins identifications were greater than the differences in peptide identifications indicating that the major source of the disparity may be at the protein inference grouping level. The data also revealed that analysis of 2 technical replicates can increase protein identifications by up to 10-15%, while a third replicate results in an additional 4-5%.

Conclusions: The data emphasize two practical methods of increasing the robustness of mass spectrometry data analysis. The data show that 1) using multiple search engines can expand the number of identified proteins (union) and validate protein identifications (intersection), and 2) analysis of 2 or 3 technical replicates can substantially expand protein identifications. Moreover, information can be extracted from a dataset by performing database searching with different engines and performing technical repeats, which requires no additional sample preparation and effectively utilizes research time and effort.

During a screen of bacterial nutrients as inhibitors of Escherichia coli O157:H7 biofilm, the Prüß research team made an intriguing observation: among 95 carbon and 95 nitrogen sources tested, β-phenylethylamine (PEA) performed best at reducing bacterial cell counts and biofilm amounts, when supplemented to liquid beef broth medium. This review article summarizes what is known about PEA. After some starting information on the chemistry of the molecule, we focus on PEA as a neurotransmitter and then move on to its role in food processing. PEA is a trace amine whose molecular mechanism of action differs from biogenic amines, such as serotonin or dopamine. Especially low or high concentrations of PEA may be associated with specific psychological disorders. For those disorders that are characterized by low PEA levels (e.g. attention deficit hyperactivity disorder), PEA has been suggested as a 'safe' alternative to drugs, such as amphetamine or methylphenidate, which are accompanied by many undesirable side effects. On the food processing end, PEA can be detected in food either as a result of microbial metabolism or thermal processing. PEA's presence in food can be used as an indicator of bacterial contamination.

A previous study postulated that acetate metabolism was a metabolic sensory mechanism that related information about E. coli's environment to the formation of biofilms (Prüβ et al., Arch. Microbiol. 2010). Considering that mutants in pta ackA (no acetyl phosphate) and ackA (high acetyl phosphate) exhibited similarly increased biofilm amounts and three dimensional structures, the hypothesis for this study was that acetyl Co-A was a more likely mediator of the acetate effect than acetyl phosphate. The effect of acetate metabolism on biofilm amounts was detailed by using single carbon sources rather than the previously used mixed amino acid medium, as well as mutations in additional genes that contribute to acetate metabolism (ldhA, pflA, pflB). In summary, the mutations in ackA, pta ackA, and ldhA increased biofilm amounts in the presence of maltose, D-trehalose, D-mannose, and L-rhamnose, all of which get converted to acetyl-CoA. The ackA mutant also exhibited increased biofilm amounts in the presence of inosine and thymidine. The mutation in pflA decreased biofilm amounts in the presence of maltotriose, uridine, D-serine, and acetate. Since ackA, pta ackA, and ldhA mutants are expected to exhibit increased intracellular acetyl-CoA levels, and pflA and pflB mutants likely exhibit decreased acetyl-CoA concentrations, we believe that acetyl-CoA is the activated acetate intermediate that controls biofilm amounts.

We report a case of paradoxical patellar reflex as a presenting sign of acute inflammatory demyelinating polyradiculoneuropathy.