Metabolism of indole-3-acetic acid and indole-3-methanol in wheat leaf segments

Indole-3-methanol is a product of indole-3-acetic acid metabolism in wheat leaves ( Triticum compactum Host., cv. Little Club). It leads either to the production of the corresponding aldehyde and carboxylic acid, to the production of a polar glucoside which releases indole-3-methanol on β-glucosidase treatment, or to an unidentified apolar product on mild alkaline hydrolysis in aqueous methanol. With reference to a published pathway of indole-3-acetic acid degradation, the results provide evidence for a prominent role of indole-3-methanol and also for the occurrence of co-oxidation processes in wheat leaves involving indole-3-acetic acid and phenolic cosubstrates.     

Regulatory RNAs and beyond

The dynamic regulation of biological processes by RNA has emerged as a key field in recent years, and was the topic of the 62nd Mosbacher Colloquium of the German Society for Biochemistry and Molecular Biology (GBM). The 2011 Colloquium, held in April in the romantic Neckar-river region, was also a celebration of the tenth anniversary of the RNA Biochemistry study group within the GBM, which acts as platform for RNA biologists and chemists within Germany and in other European countries.     

Identification of evolutionarily conserved genetic regulators of cellular aging

To identify new genetic regulators of cellular aging and senescence, we performed genome-wide comparative RNA profiling with selected human cellular model systems, reflecting replicative senescence, stress-induced premature senescence, and distinct other forms of cellular aging. Gene expression profiles were measured, analyzed, and entered into a newly generated database referred to as the GiSAO database. Bioinformatic analysis revealed a set of new candidate genes, conserved across the majority of the cellular aging models, which were so far not associated with cellular aging, and highlighted several new pathways that potentially play a role in cellular aging. Several candidate genes obtained through this analysis have been confirmed by functional experiments, thereby validating the experimental approach. The effect of genetic deletion on chronological lifespan in yeast was assessed for 93 genes where (i) functional homologues were found in the yeast genome and (ii) the deletion strain was viable. We identified several genes whose deletion led to significant changes of chronological lifespan in yeast, featuring both lifespan shortening and lifespan extension. In conclusion, an unbiased screen across species uncovered several so far unrecognized molecular pathways for cellular aging that are conserved in evolution.     

Multiple Lytic Origins of Replication Are Required for Optimal Gammaherpesvirus Fitness In Vitro and In Vivo

An unresolved question in herpesvirus biology is why some herpesviruses contain more than one lytic origin of replication (oriLyt). Using murine gammaherpesvirus 68 (MHV-68) as model virus containing two oriLyts, we demonstrate that loss of either of the two oriLyts was well tolerated in some situations but not in others both in vitro and in vivo. This was related to the cell type, the organ or the route of inoculation. Depending on the cell type, different cellular proteins, for example Hexim1 and Rbbp4, were found to be associated with oriLyt DNA. Overexpression or downregulation of these proteins differentially affected the growth of mutants lacking either the left or the right oriLyt. Thus, multiple oriLyts are required to ensure optimal fitness in different cell types and tissues.     

Chemical derivatization of histones for facilitated analysis by mass spectrometry

Histone post-translational modifications have been recently intensely studied owing to their role in regulating gene expression. Here, we describe protocols for the characterization of histone modifications in both qualitative and semiquantitative manners using chemical derivatization and tandem mass spectrometry. In these procedures, extracted histones are first derivatized using propionic anhydride to neutralize charge and block lysine residues, and are subsequently digested using trypsin, which, under these conditions, cleaves only the arginine residues. The generated peptides can be easily analyzed using online LC-electrospray ionization-tandem mass spectrometry to identify the modification site. In addition, a stable isotope-labeling step can be included to modify carboxylic acid groups allowing for relative quantification of histone modifications. This methodology has the advantage of producing a small number of predicted peptides from highly modified proteins. The protocol should take approximately 15-19 h to complete, including all chemical reactions, enzymatic digestion and mass spectrometry experiments.     

Age-related changes in immunity: implications for vaccination in the elderly

Average life expectancy is continuously rising in all developed countries, leading to an ever-increasing elderly population. Of the many functions of the body affected by the complex process of ageing, the immune system in particular undergoes various changes, collectively termed immunosenescence. As a result, elderly people are more susceptible to infections and are frequently less protected by vaccines. This review summarises the effect of ageing on immunity, emphasising the age-associated changes within T and B cells at a molecular and cellular level. Furthermore, it discusses strategies, such as the addition of immunostimulatory adjuvants and the use of potent antigen-delivery systems, that may counteract age-related defects in immune responses to vaccination. A proper understanding of how immunological memory is affected by ageing, and the introduction of strategies to ameliorate vaccine efficacy in the elderly, might reduce the incidence and the severity of infectious disease within this fragile age group and have a strong impact on the quality of life of elderly individuals.     

Acute diarrhea in west african children: diverse enteric viruses and a novel parvovirus genus

Parvoviruses cause a variety of mild to severe symptoms or asymptomatic infections in humans and animals. During a viral metagenomic analysis of feces from children with acute diarrhea in Burkina Faso, we identified in decreasing prevalence nucleic acids from anelloviruses, dependoviruses, sapoviruses, enteroviruses, bocaviruses, noroviruses, adenoviruses, parechoviruses, rotaviruses, cosavirus, astroviruses, and hepatitis B virus. Sequences from a highly divergent parvovirus, provisionally called bufavirus, were also detected whose NS1 and VP1 proteins showed <39% and <31% identities to those of previously known parvoviruses. Four percent of the fecal samples were PCR positive for this new parvovirus, including a related bufavirus species showing only 72% identity in VP1. The high degree of genetic divergence of these related genomes from those of other parvoviruses indicates the presence of a proposed new Parvoviridae genus containing at least two species. Studies of the tropism and pathogenicity of these novel parvoviruses will be facilitated by the availability of their genome sequences.     

Non-omnivorous generality promotes population stability

Using a combination of stable isotope analysis of delta13C and delta15N and long-term census data on population abundances for meiofauna in tropical aquatic rock pools, we provide evidence that species which exhibit greater variation in delta13C, an indication of a greater range of distinct carbon sources in their diet, have more stable populations than species with lower variation in delta13C. This link between increased isotope variability and reduced population variability, however, did not hold for delta15N. This suggests that increases in population stability were due to non-omnivorous feeding on multiple carbon sources within a trophic level rather than omnivorous feeding on multiple carbon sources across trophic levels. Our findings corroborate MacArthur's original hypothesis that populations that can access a greater range of resources are more stable than those which consume a more restricted range of resources.