Ribosomal proteins as biomarkers for bacterial identification by mass spectrometry in the clinical microbiology laboratory

Whole-cell matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) is a rapid method for identification of microorganisms that is increasingly used in microbiology laboratories. This identification is based on the comparison of the tested isolate mass spectrum with reference databases. Using Neisseria meningitidis as a model organism, we showed that in one of the available databases, the Andromas database, 10 of the 13 species-specific biomarkers correspond to ribosomal proteins. Remarkably, one biomarker, ribosomal protein L32, was subject to inter-strain variability. The analysis of the ribosomal protein patterns of 100 isolates for which whole genome sequences were available, confirmed the presence of inter-strain variability in the molecular weight of 29 ribosomal proteins, thus establishing a correlation between the sequence type (ST) and/or clonal complex (CC) of each strain and its ribosomal protein pattern. Since the molecular weight of three of the variable ribosomal proteins (L30, L31 and L32) was included in the spectral window observed by MALDI-TOF MS in clinical microbiology, i.e., 3640–12000 m/z, we were able by analyzing the molecular weight of these three ribosomal proteins to classify each strain in one of six subgroups, each of these subgroups corresponding to specific STs and/or CCs. Their detection by MALDI-TOF allows therefore a quick typing of N. meningitidis isolates.     

Mutations in BICD2, which Encodes a Golgin and Important Motor Adaptor,Cause Congenital Autosomal-Dominant Spinal Muscular Atrophy

Spinal muscular atrophy (SMA) is a heterogeneous group of neuromuscular disorders caused by degeneration of lower motor neurons. Although functional loss of SMN1 is associated with autosomal-recessive childhood SMA, the genetic cause for most families affected by dominantly inherited SMA is unknown. Here, we identified pathogenic variants in bicaudal D homolog 2 (Drosophila) (BICD2) in three families afflicted with autosomal-dominant SMA. Affected individuals displayed congenital slowly progressive muscle weakness mainly of the lower limbs and congenital contractures. In a large Dutch family, linkage analysis identified a 9q22.3 locus in which exome sequencing uncovered c.320C>T (p.Ser107Leu) in BICD2. Sequencing of 23 additional families affected by dominant SMA led to the identification of pathogenic variants in one family from Canada (c.2108C>T [p.Thr703Met]) and one from the Netherlands (c.563A>C [p.Asn188Thr]). BICD2 is a golgin and motor-adaptor protein involved in Golgi dynamics and vesicular and mRNA transport. Transient transfection of HeLa cells with all three mutant BICD2 cDNAs caused massive Golgi fragmentation. This observation was even more prominent in primary fibroblasts from an individual harboring c.2108C>T (p.Thr703Met) (affecting the C-terminal coiled-coil domain) and slightly less evident in individuals with c.563A>C (p.Asn188Thr) (affecting the N-terminal coiled-coil domain). Furthermore, BICD2 levels were reduced in affected individuals and trapped within the fragmented Golgi. Previous studies have shown that Drosophila mutant BicD causes reduced larvae locomotion by impaired clathrin-mediated synaptic endocytosis in neuromuscular junctions. These data emphasize the relevance of BICD2 in synaptic-vesicle recycling and support the conclusion that BICD2 mutations cause congenital slowly progressive dominant SMA.     

No evidence for DUP25 in patients with panic disorder using a quantitative real-time PCR approach

A duplication of chromosome 15q24-q26 (DUP25) has been reported to be associated with anxiety disorders. We tested for the presence of DUP25 in a sample of 50 patients with panic disorder and 50 controls using a quantitative real-time PCR approach. Contrary to the original finding, our results were compatible with the absence of DUP25, and no significant difference could be detected between patients and controls (P=1.0). Thus, our study does not support the hypothesis of an involvement of DUP25 in panic disorder.     

Predominance of HA-222D/G Polymorphism in Influenza A(H1N1)pdm09 Viruses Associated with Fatal and Severe Outcomes Recently Circulating in Germany

Influenza A(H1N1)pdm09 viruses cause sporadically very severe disease including fatal clinical outcomes associated with pneumonia, viremia and myocarditis. A mutation characterized by the substitution of aspartic acid (wild-type) to glycine at position 222 within the haemagglutinin gene (HA-D222G) was recorded during the 2009 H1N1 pandemic in Germany and other countries with significant frequency in fatal and severe cases. Additionally, A(H1N1)pdm09 viruses exhibiting the polymorphism HA-222D/G/N were detected both in the respiratory tract and in blood. Specimens from mild, fatal and severe cases were collected to study the heterogeneity of HA-222 in A(H1N1)pdm09 viruses circulating in Germany between 2009 and 2011. In order to enable rapid and large scale analysis we designed a pyrosequencing (PSQ) assay. In 2009/2010, the 222D wild-type of A(H1N1)pdm09 viruses predominated in fatal and severe outcomes. Moreover, co-circulating virus mutants exhibiting a D222G or D222E substitution (8/6%) as well as HA-222 quasispecies were identified (10%). Both the 222D/G and the 222D/G/N/V/Y polymorphisms were confirmed by TA cloning. PSQ analyses of viruses associated with mild outcomes revealed mainly the wild-type 222D and no D222G change in both seasons. However, an increase of variants with 222D/G polymorphism (60%) was characteristic for A(H1N1)pdm09 viruses causing fatal and severe cases in the season 2010/2011. Pure 222G viruses were not observed. Our results support the hypothesis that the D222G change may result from adaptation of viral receptor specificity to the lower respiratory tract. This could explain why transmission of the 222G variant is less frequent among humans. Thus, amino acid changes at HA position 222 may be the result of viral intra-host evolution leading to the generation of variants with an altered viral tropism.     

Pandemic human viruses cause decline of endangered great apes

Commercial hunting and habitat loss are major drivers of the rapid decline of great apes [1]. Ecotourism and research have been widely promoted as a means of providing alternative value for apes and their habitats [2]. However, close contact between humans and habituated apes during ape tourism and research has raised concerns that disease transmission risks might outweigh benefits [3-7]. To date only bacterial and parasitic infections of typically low virulence have been shown to move from humans to wild apes [8, 9]. Here, we present the first direct evidence of virus transmission from humans to wild apes. Tissue samples from habituated chimpanzees that died during three respiratory-disease outbreaks at our research site, C?te d'Ivoire, contained two common human paramyxoviruses. Viral strains sampled from chimpanzees were closely related to strains circulating in contemporaneous, worldwide human epidemics. Twenty-four years of mortality data from observed chimpanzees reveal that such respiratory outbreaks could have a long history. In contrast, survey data show that research presence has had a strong positive effect in suppressing poaching around the research site. These observations illustrate the challenge of maximizing the benefit of research and tourism to great apes while minimizing the negative side effects.     

In vitro and ex vivo evaluation of second-generation histone deacetylase inhibitors for the treatment of spinal muscular atrophy

Among a panel of histone deacetylase (HDAC) inhibitors investigated, suberoylanilide hydroxamic acid (SAHA) evolved as a potent and non-toxic candidate drug for the treatment of spinal muscular atrophy (SMA), an alpha-motoneurone disorder caused by insufficient survival motor neuron (SMN) protein levels. SAHA increased SMN levels at low micromolar concentrations in several neuroectodermal tissues, including rat hippocampal brain slices and motoneurone-rich cell fractions, and its therapeutic capacity was confirmed using a novel human brain slice culture assay. SAHA activated survival motor neuron gene 2 (SMN2), the target gene for SMA therapy, and inhibited HDACs at submicromolar doses, providing evidence that SAHA is more efficient than the HDAC inhibitor valproic acid, which is under clinical investigation for SMA treatment. In contrast to SAHA, the compounds m-Carboxycinnamic acid bis-Hydroxamide, suberoyl bishydroxamic acid and M344 displayed unfavourable toxicity profiles, whereas MS-275 failed to increase SMN levels. Clinical trials have revealed that SAHA, which is under investigation for cancer treatment, has a good oral bioavailability and is well tolerated, allowing in vivo concentrations shown to increase SMN levels to be achieved. Because SAHA crosses the blood-brain barrier, oral administration may allow deceleration of progressive alpha-motoneurone degeneration by epigenetic SMN2 gene activation.