Testosterone and intrasexual competition in men: is there any relation with digit ratio (2D:4D)?

Digit ratio 2D:4D is a sexually dimorphic characteristic and it is believed that this difference is related to high levels of prenatal testosterone and circulating testosterone in men. High levels of testosterone are also associated with traits related to competitiveness. Therefore, this study aimed to examine the relation between intrasexual competition and 2D:4D in men. One hundred thirteen college men answered a questionnaire to measure their scores of intrasexual competition and donated a saliva sample to measure their testosterone levels; finally, the finger length from both hands was measured. It was found a positive correlation between testosterone levels and intrasexual competition scores, and a negative correlation between testosterone levels and left 2D:4D. Finally, we did not find a significant association between digit ratios 2D:4D and intrasexual competition scores. Our study shows that men with higher testosterone levels also have higher intrasexual competition scores and lower values of left digit ratio 2D:4D. Further studies will have to take into account fluctuations in testosterone over the time to observe if the relation between competitiveness scores and digit ratios 2D:4D becomes significant.     

Identification of the bona fide DHDPS from a common plant pathogen

Agrobacterium tumefaciens is a Gram‐negative soil‐borne bacterium that causes Crown Gall disease in many economically important crops. The absence of a suitable chemical treatment means there is a need to discover new anti‐Crown Gall agents and also characterize bona fide drug targets. One such target is dihydrodipicolinate synthase (DHDPS), a homo‐tetrameric enzyme that catalyzes the committed step in the metabolic pathway yielding meso‐diaminopimelate and lysine. Interestingly, there are 10 putative DHDPS genes annotated in the A. tumefaciens genome, including three whose structures have recently been determined (PDB IDs: 3B4U, 2HMC, and 2R8W). However, we show using quantitative enzyme kinetic assays that nine of the 10 dapA gene products, including 3B4U, 2HMC, and 2R8W, lack DHDPS function in vitro. A sequence alignment showed that the product of the dapA7 gene contains all of the conserved residues known to be important for DHDPS catalysis and allostery. This gene was cloned and the recombinant product expressed and purified. Our studies show that the purified enzyme (i) possesses DHDPS enzyme activity, (ii) is allosterically inhibited by lysine, and (iii) adopts the canonical homo‐tetrameric structure in both solution and the crystal state. This study describes for the first time the structure, function and allostery of the bona fide DHDPS from A. tumefaciens, which offers insight into the rational design of pesticide agents for combating Crown Gall disease. Proteins 2014; 82:1869–1883. © 2014 Wiley Periodicals, Inc.     

Modulation of peroxisomal and microsomal fatty acid oxidation by acetone. A comparative study between liver and kidney

The effect of acetone consumption on some microsomal and peroxisomal activities was studied in rat kidney and these results were compared with data from former investigations in liver. Acetone increased the microsomal lauric acid hydroxylation, the aminopyrine N-demethylation catalyzed by cytochrome P450 and the microsomal UDP-glucuronyltransferase activity. Also, acetone increased the peroxisomal β-oxidation of palmitoyl CoA and catalase activities in kidney. These studies suggest that acetone is a common inducer of the microsomal and peroxisomal fatty acid oxidation, as previously shown in both starved and ethanol treated rats. Our results support the hypothesis that microsomal fatty acid ω-hydroxylation results in the generation of substrates being supplied for peroxisomal β-oxidation. We propose that the final purpose of these linked fatty acid oxidations could be the catabolism of fatty acids or the generation of a substrate for the synthesis of glucose from fatty acids. This pathway would be triggered by acetone treatment in a similar way in liver and kidney.