Large D/H variations in bacterial lipids reflect central metabolic pathways

Large hydrogen-isotopic (D/H) fractionations between lipids and growth water have been observed in most organisms studied to date. These fractionations are generally attributed to isotope effects in the biosynthesis of lipids, and are frequently assumed to be approximately constant for the purpose of reconstructing climatic variables. Here, we report D/H fractionations between lipids and water in 4 cultured members of the phylum Proteobacteria, and show that they can vary by up to 500‰ in a single organism. The variation cannot be attributed to lipid biosynthesis as there is no significant change in these pathways between cultures, nor can it be attributed to changing substrate D/H ratios. More importantly, lipid/water D/H fractionations vary systematically with metabolism: chemoautotrophic growth (approximately −200 to −400‰), photoautotrophic growth (−150 to −250‰), heterotrophic growth on sugars (0 to −150‰), and heterotrophic growth on TCA-cycle precursors and intermediates (−50 to +200‰) all yield different fractionations. We hypothesize that the D/H ratios of lipids are controlled largely by those of NADPH used for biosynthesis, rather than by isotope effects within the lipid biosynthetic pathway itself. Our results suggest that different central metabolic pathways yield NADPH—and indirectly lipids—with characteristic isotopic compositions. If so, lipid δD values could become an important biogeochemical tool for linking lipids to energy metabolism, and would yield information that is highly complementary to that provided by ^(13)C about pathways of carbon fixation

CASK regulates CaMKII autophosphorylation in neuronal growth, calcium signaling, and learning

Calcium (Ca2+)/calmodulin (CaM)-dependent kinase II (CaMKII) activity plays a fundamental role in learning and memory. A key feature of CaMKII in memory formation is its ability to be regulated by autophosphorylation, which switches its activity on and off during synaptic plasticity. The synaptic scaffolding protein CASK (calcium (Ca2+)/calmodulin (CaM) associated serine kinase) is also important for learning and memory, as mutations in CASK result in intellectual disability and neurological defects in humans. We show that in Drosophila larvae, CASK interacts with CaMKII to control neuronal growth and calcium signalling. Furthermore, deletion of the CaMK-like and L27 domains of CASK (CASK β null) or expression of overactive CaMKII (T287D) produced similar effects on synaptic growth and Ca2+ signalling. CASK overexpression rescues the effects of CaMKII overactivity, consistent with the notion that CASK and CaMKII act in a common pathway that controls these neuronal processes. The reduction in Ca2+ signalling observed in the CASK β null mutant caused a decrease in vesicle trafficking at synapses. In addition, the decrease in Ca2+ signalling in CASK mutants was associated with an increase in Ether-à-go-go (EAG) potassium (K+) channel localisation to synapses. Reducing EAG restored the decrease in Ca2+ signalling observed in CASK mutants to the level of wildtype, suggesting that CASK regulates Ca2+ signalling via EAG. CASK knockdown reduced both appetitive associative learning and odour evoked Ca2+ responses in Drosophila mushroom bodies, which are the learning centres of Drosophila. Expression of human CASK in Drosophila rescued the effect of CASK deletion on the activity state of CaMKII, suggesting that human CASK may also regulate CaMKII autophosphorylation

Mycobacterium tuberculosis lineage: a naming of the parts

There have been many reports of groups of related Mycobacterium tuberculosis strains described variously as lineages, families or clades. There is no objective definition of these groupings making it impossible to define relationships between those groups with biological advantages. Here we describe two groups of related strains obtained from an epidemiological study in Tanzania which we define as the Kilimanjaro and Meru lineages on the basis of IS6110 restriction fragment length polymorphism (RFLP), polymorphic GC rich sequence (PGRS) RFLP and mycobacterial interspersed repeat unit (MIRU) typing. We investigated the concordance between each of the typing techniques and the dispersal of the typing profiles from a core pattern. The Meru lineage is more dispersed than the Kilimanjaro lineage and we speculate that the Meru lineage is older. We suggest that this approach provides an objective definition that proves robust in this epidemiological study. Such a framework will permit associations between a lineage and clinical or bacterial phenomenon to be tested objectively. This definition will also enable new putative lineages to be objectively tested

Picturing the Way in Bae Yong-kyun\u27s Why Has Bodhidharma Left for the East?

Last year the teachers of a course called Religion and Film asked me to lead a discussion of Why Has Bodhidharma Left for the East? (hereafter, Bodhidharma) a film directed by Bae Yong-Kyun that tells a story set in the context of Son Buddhism (the Zen Buddhism of Korea). This opportunity has allowed me to reflect on the use of the film in classroom teaching and to evaluate how well this particular film displays the key elements of Zen. I find Bodhidharma uses a Zen-like simplicity to teach simplicity. With an otherwise simple story, it gradually opens up Zen\u27s compelling subtlety and richness. The Zen-like simplicity is key to the movie and to teaching Zen. I hope readers will respond with ideas about how this and similar films can be used effectively in teaching and with suggestions about my interpretation of Bodhidharma as a teaching device and a religious film

Do the Poor Pay More for Healthy Food? An Empirical Economic Analysis

Food Consumption/Nutrition/Food Safety,

EFFECT OF THE 1985 FARM BILL PROVISIONS ON FARMERS' SOIL CONSERVATION DECISIONS

Conservation initiatives in the 1985 Farm Bill affected farmers' decisions regarding soil conservation. A farmer survey was conducted and a multiperiod mixed-integer programming model was developed to determine an optimal farm plan with choice of crop-tillage combinations and land retirement. Results indicate that farmers' incentives to reduce soil loss in the Sand Mountain region in Alabama are not substantially affected by provisions of the 1985 Farm Bill. The bid price for the Conservation Reserve Program will have to be considerably higher than 1988 levels to provide an incentive to remove land from production.Agricultural and Food Policy,

A Suppurative Lumbar Wound in a Saddle Horse

A three year old American Saddle gelding was referred to Stange Memorial Clinic on March 11, 1\u27950, with a suppurative wound on the back. The history indicated that a penetrating wound by a sharp pointed object had occurred about three weeks previously