RNase treatment of yeast and mammalian cell extracts affects in vitro substrate methylation by type I protein arginine N-methyltransferases.

Type I protein arginine N-methyltransferases catalyze the formation of omega-NG-monomethylarginine and asymmetric omega-NG, NG-dimethylarginine residues using S-adenosyl-l-methionine as the methyl donor. In vitro these enzymes can modify a number of soluble methyl-accepting substrates in yeast and mammalian cell extracts including several species that interact with RNA. We treated normal and hypomethylated Saccharomyces cerevisiae and RAT1 cell extracts with RNase prior to in vitro methylation by recombinant protein N-arginine methyltransferases and found that the methylation of certain polypeptides is enhanced up to 12-fold whereas that of others is diminished. 2-D gel electrophoresis of RNase-treated yeast extracts allowed us to tentatively identify the glycine- and arginine-rich (GAR) domain-containing proteins Gar1, Nop1, Sbp1, and Npl3 as major methyl-acceptors based on their known isoelectric points and apparent molecular weights. These results suggest that the methylation and RNA-binding of GAR domain-containing proteins in vivo may regulate protein-nucleic acid or protein-protein interactions.     

Use of thermometers in general practice.

OBJECTIVE--To identify the attitudes of general practitioners towards the use of thermometers in general practice. DESIGN--Postal questionnaire survey. SETTING--All general practitioners in the catchment area of Frimley Park Hospital, Surrey. SUBJECTS--145 general practitioners. MAIN OUTCOME MEASURES--Answers to questions covering a variety of aspects concerning the use of thermometers in general practice. RESULTS--116 (80%) doctors replied. Seven doctors did not have any method of taking a patient''s temperature; up to 12 more doctors did not use their thermometers and 56 doctors used them infrequently, less than once a fortnight. Mercury glass thermometers were most commonly used (80 doctors; 69%), but only 8% of doctors used them correctly. Six doctors failed to clean their thermometers between patients. The study failed to identify the roles of axillary and rectal temperature readings. CONCLUSION--There is a wide variation in attitudes towards the use of thermometers in general practice.     

Interleukin-1α Activity in Necrotic Endothelial Cells Is Controlled by Caspase-1 Cleavage of Interleukin-1 Receptor-2: IMPLICATIONS FOR ALLOGRAFT REJECTION*

Inflammation is a key instigator of the immune responses that drive atherosclerosis and allograft rejection. IL-1α, a powerful cytokine that activates both innate and adaptive immunity, induces vessel inflammation after release from necrotic vascular smooth muscle cells (VSMCs). Similarly, IL-1α released from endothelial cells (ECs) damaged during transplant drives allograft rejection. However, IL-1α requires cleavage for full cytokine activity, and what controls cleavage in necrotic ECs is currently unknown. We find that ECs have very low levels of IL-1α activity upon necrosis. However, TNFα or IL-1 induces significant levels of active IL-1α in EC necrotic lysates without alteration in protein levels. Increased activity requires cleavage of IL-1α by calpain to the more active mature form. Immunofluorescence and proximity ligation assays show that IL-1α associates with interleukin-1 receptor-2, and this association is decreased by TNFα or IL-1 and requires caspase activity. Thus, TNFα or IL-1 treatment of ECs leads to caspase proteolytic activity that cleaves interleukin-1 receptor-2, allowing IL-1α dissociation and subsequent processing by calpain. Importantly, ECs could be primed by IL-1α from adjacent damaged VSMCs, and necrotic ECs could activate neighboring normal ECs and VSMCs, causing them to release inflammatory cytokines and up-regulate adhesion molecules, thus amplifying inflammation. These data unravel the molecular mechanisms and interplay between damaged ECs and VSMCs that lead to activation of IL-1α and, thus, initiation of adaptive responses that cause graft rejection.     

Elongated hindguts in desert‐living dung beetles (Scarabaeidae: Scarabaeinae) feeding on dry dung pellets or plant litter

Most adult dung beetles (Scarabaeidae: Scarabaeinae) feed on fresh, wet dung of larger herbivorous or omnivorous mammals. As refractory plant fragments are selected out before ingestion, the food is presumed easily digestible. However, members of the desert‐living scarabaeine genus Pachysoma (probably evolved from an ancestor closely related to the wet‐dung feeding genus Scarabaeus) select dry dung pellets and/or plant litter. Thus, they ingest a much higher proportion of structural plant material, which nevertheless appears to be digested rather efficiently. This study investigates morphological modifications of the gut for this digestion in adults of eight Pachysoma species, both pellet and litter feeders. To ascertain hypothesized ancestral conditions, four fresh‐dung feeding Scarabaeus species were also examined. The latter have the usual dung beetle gut consisting of a long, simple midgut, followed by an equally simple, much shorter hindgut of the same width. Lengths of midguts (M) and hindguts (H) divided by body length (B) for comparison between species of different size are: 4.9–6.3 (M/B) and 0.7–0.8 (H/B), which is normal for dung feeders. In Pachysoma, lengths are 6.3–6.5 (M/B) and 1.0–1.4 (H/B) in pellet feeders, and 4.4–5.0 (M/B) and 2.0–2.5 (H/B) for litter feeders. Hindguts are still morphologically undifferentiated and of midgut width, but clearly longer, particularly in litter feeders. Presumably, plant fragments in the food are digested, at least partly, in the hindgut. If so, the morphological adaptation is unusual: simple elongation rather than the expansion of part of the hindgut, as found in several other plant‐ or detritus‐feeding scarabaeids. J. Morphol. 2013. © 2013 Wiley Periodicals, Inc.     

Temperature and embryonic development in polar marine invertebrates

The life-history tactics of many Antarctic marine invertebrates suggest that the commonly observed slow rates of growth are adaptations to the pattern of food availability, and not due to low temperature per se. This implies that marine invertebrates have been able, over the course of evolutionary time, to compensate their rates of embryonic development for the effect of temperature. Data from north Atlantic copepods indicate that this is so. It is therefore suggested that the slow rates of embryonic development in many Antarctic marine invertebrates are the result of large egg size, and not the low temperature. Large, slowly developing eggs are part of a suite of tactics, often called K-strategies, which characterise many marine invertebrates in Antarctica.     

A cyclodextrin-capped histone deacetylase inhibitor

We have synthesized a β-cyclodextrin (βCD)-capped histone deacetylase (HDAC) inhibitor 3 containing an alkyl linker and a zinc-binding hydroxamic acid motif. Biological evaluation (HDAC inhibition studies) of 3 enabled us to establish the effect of replacing an aryl cap (in SAHA (vorinostat,)) 1 by a large saccharidic scaffold “cap”. HDAC inhibition was observed for 3, to a lesser extent than SAHA, and rationalized by molecular docking into the active site of HDAC8. However, compound 3 displayed no cellular activity.