Phosphatidylinositolmannoside vaccination induces lipid-specific Th1-responses and partially protects guinea pigs from Mycobacterium tuberculosis challenge.

The concept of donor-unrestricted T cells (DURTs) comprises a heterogeneity of lymphoid cells that respond to an abundance of unconventional epitopes in a non-MHC-restricted manner. Vaccinologists strive to harness this so far underexplored branch of the immune system for new vaccines against tuberculosis. A particular division of DURTs are T cells that recognize their cognate lipid antigen in the context of CD1-molecules. Mycobacteria are characterized by a particular lipid-rich cell wall. Several of these lipids have been shown to be presented to T cells via CD1b-molecules. Guinea pigs functionally express CD1b and are hence an appropriate small animal model to study the role of CD1b-restricted, lipid-specific immune responses. In the current study, guinea pigs were vaccinated with BCG or highly-purified, liposome-formulated phosphatidylinositol-hexa-mannoside (PIM6) to assess the effect of CD1-restricted DURTs on the course of infection after virulent Mycobacterium tuberculosis (Mtb) challenge. Robust PIM6-specific T cell-responses were observed both after BCG- and PIM6-vaccination. The cellular response was significantly reduced in the presence of monoclonal, CD1b-blocking antibodies, indicating that a predominant part of this reactivity was CD1b-restricted. When animals were challenged with Mtb, BCG- and PIM6-vaccinated animals showed significantly reduced pathology, smaller necrotic granulomas in lymph node and spleen and reduced bacterial loads. While BCG conferred an almost sterile protection in this setting, compared to control animals' lesions were reduced roughly by two thirds in PIM6-vaccinated. Comprehensive histological and transcriptional analyses in the draining lymph node revealed that protected animals showed reduced transcription-levels of inflammatory cyto- and chemokines and higher levels of CD1b-expression on professional antigen cells compared to controls. Although BCG as a comparator induced by far stronger effects, our observations in the guinea pig model suggest that CD1b-restricted, PIM6-reactive DURTs contribute to immune-mediated containment of virulent Mtb.

Influence of root exudates on the extracellular proteome of the plant growth-promoting bacterium Bacillus amyloliquefaciens FZB42.

Proteins secreted by Bacillus amyloliquefaciens FZB42, a root-associated plant growth-promoting rhizobacterium, are thought to play an important role in the establishment of beneficial interactions with plants. To investigate the possible role of proteins in this process, extracellular proteome maps of B. amyloliquefaciens FZB42 during the late exponential and stationary growth phases were generated using 2D gel electrophoresis. Out of the 121 proteins identified by MALDI-TOF MS, 61 were predicted to contain secretion signals. A few of the others, bearing no signal peptide, have been described as elicitors of plant innate immunity, including flagellin proteins, cold-shock proteins and the elongation factor Tu, suggesting that B. amyloliquefaciens FZB42 protects plants against disease by eliciting innate immunity. Our reference maps were used to monitor bacterial responses to maize root exudates. Approximately 34 proteins were differentially secreted in response to root exudates during either the late exponential or stationary phase. These were mainly involved in nutrient utilization and transport. The protein with the highest fold change in the presence of maize root exudates during the late exponential growth phase was acetolactate synthase (AlsS), an enzyme involved in the synthesis of the volatile acetoin, known as an inducer of systemic resistance against plant pathogens and as a trigger of plant growth.

Serotonin and the neuropeptide PDF initiate and extend opposing behavioral states in C. elegans.

Foraging animals have distinct exploration and exploitation behaviors that are organized into discrete behavioral states. Here, we characterize a neuromodulatory circuit that generates long-lasting roaming and dwelling states in Caenorhabditis elegans. We find that two opposing neuromodulators, serotonin and the neuropeptide pigment dispersing factor (PDF), each initiate and extend one behavioral state. Serotonin promotes dwelling states through the MOD-1 serotonin-gated chloride channel. The spontaneous activity of serotonergic neurons correlates with dwelling behavior, and optogenetic modulation of the critical MOD-1-expressing targets induces prolonged dwelling states. PDF promotes roaming states through a Gαs-coupled PDF receptor; optogenetic activation of cAMP production in PDF receptor-expressing cells induces prolonged roaming states. The neurons that produce and respond to each neuromodulator form a distributed circuit orthogonal to the classical wiring diagram, with several essential neurons that express each molecule. The slow temporal dynamics of this neuromodulatory circuit supplement fast motor circuits to organize long-lasting behavioral states.

Proteomics analysis of hypothalamic response to energy restriction in dairy cows.

The hypothalamus is the central regulatory unit that balances a number of body functions including metabolic rate, hunger, and satiety signals. Hypothalamic neurons monitor and respond to alterations of circulating nutrients and hormones that reflect the peripheral energy status. These extracellular signals are integrated within the cell at the ATP:AMP ratio and at the level of ROS, triggering gene expression associated with glucose and lipid metabolism. In order to identify new molecular factors potentially associated with the control of energy homeostasis, metabolic adaptation, and regulation of feed intake, hypothalami from ad libitum fed and energy restricted cows were characterized using 2-DE and MALDI-TOF-MS. Among 189 different protein spots identified, nine proteins were found to be differentially expressed between groups. Beside the 5-aminoimidazole-4-carboxamide ribonucleotide formyltransferase/IMP cyclohydrolase, stress-induced phosphoprotein-1, heat shock protein 70 kDa-protein-5, dihydropyrimidinase-related protein-2, [Cu-Zn]-superoxide dismutase, ubiquitin carboxy-terminal hydrolase-L1, and inorganic pyrophosphatase were found to be up-regulated, whereas glyceraldehyde 3-phosphate dehydrogenase and aconitase-2 were down-regulated in the restricted group. In conclusion, differentially expressed proteins are related to energy and nucleotide metabolism and cellular stress under conditions of dietary energy deficiency. These proteins may be new candidate molecules that are potentially involved in signaling for maintaining energy homeostasis.

The phosphorus source phytate changes the composition of the cell wall proteome in Bacillus subtilis.

Phytate is the most abundant phosphorus source in plants. Since Bacillus subtilis is a soil-dwelling bacterium, the focus of this study was to investigate whether it can use phytate as a phosphorus source. The extracellular proteome analysis revealed that phytate is an alternative phosphorus source to overcome the phosphate starvation response in B. subtilis. However, the phytase was not induced neither under phosphate starvation conditions nor by phytate addition. Surprisingly, the proteome analyses demonstrated a re-distribution of the major cell wall protease WprA from the cell wall to the extracellular medium in phytate-supplemented medium. In contrast, several cell wall proteins such as autolysins and autolysin modifier proteins (e.g., LytB, -C, -D, -E, -F) are increased in the cell wall proteome in response to phytate which is not accompanied by increased transcription of the corresponding genes. These effects of phytate on the composition of the B. subtilis cell wall proteome do not depend on the acidic conditions, the increased sodium ion concentration, and the increased cell lysis. In addition, the previously predicted as cytoplasmic protein oxalate decarboxylase OxdC was identified as the most abundant cell wall protein which was induced at the transcriptional level due to the acidic conditions caused by phytate.