Cytochrome c‐based domain modularity governs genus‐level diversification of electron transfer to dissimilatory nitrite reduction

The genus Neisseria contains two pathogenic species (N. meningitidis and N. gonorrhoeae) in addition to a number of commensal species that primarily colonize mucosal surfaces in man. Within the genus, there is considerable diversity and apparent redundancy in the components involved in respiration. Here, we identify a unique c‐type cytochrome (c_N) that is broadly distributed among commensal Neisseria, but absent in the pathogenic species. Specifically, c_N supports nitrite reduction in N. gonorrhoeae strains lacking the cytochromes c₅ and CcoP established to be critical to NirK nitrite reductase activity. The c‐type cytochrome domain of c_N shares high sequence identity with those localized c‐terminally in c₅ and CcoP and all three domains were shown to donate electrons directly to NirK. Thus, we identify three distinct but paralogous proteins that donate electrons to NirK. We also demonstrate functionality for a N. weaverii NirK variant with a C‐terminal c‐type heme extension. Taken together, modular domain distribution and gene rearrangement events related to these respiratory electron carriers within Neisseria are concordant with major transitions in the macroevolutionary history of the genus. This work emphasizes the importance of denitrification as a selectable trait that may influence speciation and adaptive diversification within this largely host‐restricted bacterial genus.     

Adrenomedullin-epinephrine cotreatment enhances cardiac output and left ventricular function by energetically neutral mechanisms

Adrenomedullin (AM) used therapeutically reduces mortality in the acute phase of experimental myocardial infarction. However, AM is potentially deleterious in acute heart failure as it is vasodilative and inotropically neutral. AM and epinephrine (EPI) are cosecreted from chromaffin cells, indicating a physiological interaction. We assessed the hemodynamic and energetic profile of AM-EPI cotreatment, exploring whether drug interaction improves cardiac function. Left ventricular (LV) mechanoenergetics were evaluated in 14 open-chest pigs using pressure-volume analysis and the pressure-volume area-myocardial O(2) consumption (PVA-MVo(2)) framework. AM (15 ng·kg(-1)·min(-1), n = 8) or saline (controls, n = 6) was infused for 120 min. Subsequently, a concurrent infusion of EPI (50 ng·kg(-1)·min(-1)) was added in both groups (AM-EPI vs. EPI). AM increased cardiac output (CO) and coronary blood flow by 20 ± 10% and 39 ± 14% (means ± SD, P < 0.05 vs. baseline), whereas controls were unaffected. AM-EPI increased CO and coronary blood flow by 55 ± 17% and 75 ± 16% (P < 0.05, AM-EPI interaction) compared with 13 ± 12% (P < 0.05 vs. baseline) and 18 ± 31% (P = not significant) with EPI. LV systolic capacitance decreased by -37 ± 22% and peak positive derivative of LV pressure (dP/dt(max)) increased by 32 ± 7% with AM-EPI (P < 0.05, AM-EPI interaction), whereas no significant effects were observed with EPI. Mean arterial pressure was maintained by AM-EPI and tended to decrease with EPI (+2 ± 13% vs. -11 ± 10%, P = not significant). PVA-MVo(2) relationships were unaffected by all treatments. In conclusion, AM-EPI cotreatment has an inodilator profile with CO and LV function augmented beyond individual drug effects and is not associated with relative increases in energetic cost. This can possibly take the inodilator treatment strategy beyond hemodynamic goals and exploit the cardioprotective effects of AM in acute heart failure.     

Mitogenome polymorphism in a single branch sample revealed by SOLiD deep sequencing of the Lophelia pertusa coral genome

We present an initial genomic analysis of the non-symbiotic scleractinian coral Lophelia pertusa, the dominant cold-water reef-building coral species in the North Atlantic Ocean. A significant fraction of the deep sequencing reads was of mitochondrial and microbial origins. SOLiD deep sequencing reads from fragment library experiments of total DNA and PCR amplified mitogenome generated about 21,000 times and 136,000 times coverage, respectively, of the 16,150bp mitogenome. Five polymorphic sites that include two non-synonymous sites in the NADH dehydrogenase subunit 5 genes were detected in both experiments. This observation is surprising since anthozoans in general exhibit very low mtDNA sequence variation at intraspecific level compared to nuclear sequences. More than fifty bacterial species associated with the coral isolate were also sequence detected, representing at least ten complete genomes. Most reads, however, were predicted to originate from the Lophelia nuclear genome.     

Dissimilar effects of one- and three-set strength training on strength and muscle mass gains in upper and lower body in untrained subjects

The purpose of this study was to compare the effects of single- and multiple-set strength training on hypertrophy and strength gains in untrained men. Twenty-one young men were randomly assigned to either the 3L-1UB group (trained 3 sets in leg exercises and 1 set in upper-body exercises; n = 11), or the 1L-3UB (trained 1 set in leg exercises and 3 sets in upper-body exercises; n = 10). Subjects trained 3 days per week for 11 weeks and each workout consisted of 3 leg exercises and 5 upper-body exercises. Training intensity varied between 10 repetition maximum (RM) and 7RM. Strength (1RM) was tested in all leg and upper-body exercises and in 2 isokinetic tests before training, and after 3, 6, 9, and 11 weeks of training. Cross sectional area (CSA) of thigh muscles and the trapezius muscle and body composition measures were performed before training, and after 5 and 11 weeks of training. The increase in 1RM from week 0 to 11 in the lower-body exercises was significantly higher in the 3L-1UB group than in the 1L-3UB group (41 vs. 21%; p < 0.001), while no difference existed between groups in upper-body exercises. Peak torque in maximal isokinetic knee-extension and thigh CSA increased more in the 3L-1UB group than in the 1L-3UB group (16 vs. 8%; p = 0.03 and 11 vs. 7%; p = 0.01, respectively), while there was no significant difference between groups in upper trapezius muscle CSA. The results demonstrate that 3-set strength training is superior to 1-set strength training with regard to strength and muscle mass gains in the leg muscles, while no difference exists between 1- and 3-set training in upper-body muscles in untrained men.     

Carotenoids‐based reddish pelvic spines in nonreproducing female and male sticklebacks (Gasterosteus aculeatus) – Signalling social dominance?

Conspicuous ornaments are often considered a result of evolution by sexual selection. According to the social selection hypothesis, such conspicuous traits may also evolve as badges of status associated with increased boldness or aggression toward conspecifics in conflicts about ecological resources. This study tested predictions from the social selection hypothesis to explain evolution of conspicuous red color of the pelvic spines of the three‐spine stickleback (Gasterosteus aculeatus). Wild nonreproducing sticklebacks were presented to pairs of dummies which differed at their pelvic spines, having either (i) normal‐sized gray or red pelvic spines or (ii) normal‐sized gray or large red pelvic spines. The experimental tank was illuminated by white or green light, since green light impedes the sticklebacks’ ability to detect red color. The dummies moved slowly around in circles at each end of the experimental tank. We quantified the parameters (i) which of the two dummies was visited first, (ii) time taken before the first visit to a dummy, (iii) distribution of the focal sticklebacks in the two zones close to each of the two dummies and in the neutral zone of the tank, (iv) close to which of the two dummies did the focal fish eat its first food‐piece, and (v) time spent until the first piece of food was eaten. This was carried out for 22 females and 29 males sticklebacks. The results suggested no effect of the color or size of the dummies’ pelvic spines, on none of the five behavioral parameters. Moreover, neither the color of the pelvic spines of the focal sticklebacks themselves (as opposed to redness of the dummies’ spines) nor their body length was associated with behavior toward the dummies. Thus, this study did not support predictions from the social selection hypothesis to explain evolution of red pelvic spines in sticklebacks.     

A paretic condition in an Anaplasma phagocytophilum infected roe deer calf

This paper describes a case of Anaplasma phagocytophilum infection in a roe deer (Capreolus capreolus) calf in Norway. The calf was found deserted, paretic, and heavily infested with Ixodes ricinus ticks. It was euthanized and investigated postmortem. Anaplasma phagocytophilum was detected in several tissues by polymerase chain reaction (PCR) and 16S rRNA sequence analyses. Analyses for Borrelia burgdorferi sensu lato and tick-borne encephalitis (TBE) virus infections were negative. This is the first report of a possible paretic condition in A. phagocytophilum infected roe deer.