Ghost Peaks of Aromatic Metabolites Induced by Corona Discharge Artifacts in LC-ESI-MS/MS.

LC-ESI-MS/MS is a preferred method for detecting and identifying metabolites, including those that are unpredictable from the genome, especially in basal metazoans like Cnidaria, which diverged earlier than bilaterians and whose metabolism is poorly understood. However, the unexpected appearance of a "ghost peak" for dopamine, which exhibited the same m/z value and MS/MS product ion spectrum during an analysis of Nematostella vectensis, a model cnidarian, complicated its accurate identification. Understanding the mechanism by which "ghost peaks" appear is crucial to accurately identify the monoamine repertoire in early animals so as to avoid misassignments.

[A case of anti-ganglioside antibody-positive Guillain-Barré syndrome with asymmetrical muscle weakness throughout the course of the disease].

A 56-year-old woman who presented with left drop foot and low back pain a week after the onset of diarrhea. Neurological symptoms progressed for a week and gradually improved thereafter. No weakness was observed in upper limbs and clearly asymmetrical muscle weakness was observed in left lower limbs during the course of the disease.

Mobilize a Proton to Transform the Collision-Induced Dissociation Spectral Pattern of a Cyclic Peptide.

The collision-induced dissociation (CID) behaviors of protonated molecules of anabaenopeptins, a group of cyanobacterial cyclic peptides, were investigated in detail using liquid chromatography-tandem mass spectrometry. Although anabaenopeptin A and B share a macrocyclic peptide structure, they give strikingly different fragmentation patterns; the former gives a variety of product ions including cleavages in the cyclic peptide structure, which is useful for structural analysis; whereas the latter gives far fewer product ions and no fragmentation in the cyclic moiety. Energy-resolved CID experiments clarified the mechanism behind the striking difference attributable to the difference in exocyclic amino acid residues, Tyr or Arg.

Characterization of eight types of 17β-hydroxysteroid dehydrogenases from the Japanese sardine Sardinops melanostictus: The probable role of type 12a in ovarian estradiol synthesis.

17β-hydroxysteroid dehydrogenases (Hsd17bs) play a critical role in sex steroid biosynthesis. Although multiple types of Hsd17b have been found in fish, there is limited research on their expression and function. Recently, we succeeded in identifying eight types of Hsd17b (types 3, 4, 7, 8, 10, 12a, 12b, and 14) by RNA sequencing in the Japanese sardine Sardinops melanostictus, a commercially important clupeoid fish; however, a homologous sequence of Hsd17b1, which catalyzes the key reaction of estradiol-17β (E2) synthesis, was absent.

[A case of tuberculous meningitis diagnosed early by direct Loop-Mediated Isothermal Amplification (LAMP) method using centrifuged medium of cerebrospinal fluid culture].

Tuberculous meningitis (TBM) is a central nervous system infection with a high mortality rate and requires early diagnosis and treatment. Identification of Mycobacterium tuberculosis in the cerebrospinal fluid is of primary importance in the diagnosis of TBM, however, conventional methods have some disadvantages: Rapid results tests such as smear and regular PCR method do not have sufficient diagnostic sensitivity; Nested PCR, which is one of the most sensitive tests, is not available in all facilities; Culture tests require a long period of 4-8 weeks for results. Here we report a case of TBM, diagnosed 14 days earlier than culture test by direct Loop-Mediated Isothermal Amplification (LAMP) method using centrifuged medium of cerebrospinal fluid (day 18) culture.