SrnR from Streptomyces griseus is a nickel-binding transcriptional activator

JBIC Journal of Biological Inorganic Chemistry - Nickel ions are crucial components for the catalysis of biological reactions in prokaryotic organisms. As an uncontrolled nickel trafficking is...     

A revised root for the human Y chromosomal phylogenetic tree: the origin of patrilineal diversity in Africa

To shed light on the structure of the basal backbone of the human Y chromosome phylogeny, we sequenced about 200 kb of the male-specific region of the human Y chromosome (MSY) from each of seven Y chromosomes belonging to clades A1, A2, A3, and BT. We detected 146 biallelic variant sites through this analysis. We used these variants to construct a patrilineal tree, without taking into account any previously reported information regarding the phylogenetic relationships among the seven Y chromosomes here analyzed. There are several key changes at the basal nodes as compared with the most recent reference Y chromosome tree. A different position of the root was determined, with important implications for the origin of human Y chromosome diversity. An estimate of 142 KY was obtained for the coalescence time of the revised MSY tree, which is earlier than that obtained in previous studies and easier to reconcile with plausible scenarios of modern human origin. The number of deep branchings leading to African-specific clades has doubled, further strengthening the MSY-based evidence for a modern human origin in the African continent. An analysis of 2204 African DNA samples showed that the deepest clades of the revised MSY phylogeny are currently found in central and northwest Africa, opening new perspectives on early human presence in the continent.     

Running backwards: soft landing–hard takeoff,a less efficient rebound

Human running at low and intermediate speeds is characterized by a greater average force exerted after ‘landing’, when muscle–tendon units are stretched (‘hard landing’), and a lower average force exerted before ‘takeoff’, when muscle–tendon units shorten (‘soft takeoff’). This landing–takeoff asymmetry is consistent with the force–velocity relation of the ‘motor’ (i.e. with the basic property of muscle to resist stretching with a force greater than that developed during shortening), but it may also be due to the ‘machine’ (e.g. to the asymmetric lever system of the foot operating during stance). Hard landing and soft takeoff—never the reverse—were found in running, hopping and trotting animals using diverse lever systems, suggesting that the different machines evolved to comply with the basic force–velocity relation of the motor. Here we measure the mechanical energy of the centre of mass of the body in backward running, an exercise where the normal coupling between motor and machine is voluntarily disrupted, in order to see the relevance of the motor–machine interplay in human running. We find that the landing–takeoff asymmetry is reversed. The resulting ‘soft landing’ and ‘hard takeoff’ are associated with a reduced efficiency of positive work production. We conclude that the landing–takeoff asymmetry found in running, hopping and trotting is the expression of a convenient interplay between motor and machine. More metabolic energy must be spent in the opposite case when muscle is forced to work against its basic property (i.e. when it must exert a greater force during shortening and a lower force during stretching).     

Application of enhanced stromal vascular fraction and fat grafting mixed with PRP in post-traumatic lower extremity ulcers

BackgroundThe authors presented their experience in regenerative surgery of post-traumatic lower extremity ulcers, evaluating the effects related to the use of Enhanced Stromal Vascular Fraction (e-SVF) and Fat Grafting with Platelet rich Plasma (PRP). The authors compared the results of two control groups.MethodThe analysis involved 20 patients aged between 23 to 62 years affected by post-traumatic lower extremity ulcers. 10 patients managed with e-SVF and 10 patients managed with Fat grafting + PRP in the Plastic and Reconstructive Surgery Department at “Tor Vergata” University Rome. Patients in the first control group (n = 10), were treated only with curettage and application of hyaluronic acid in the bed of ulcers. Patients in the second control group (n = 10), were treated only with PRP.ResultsThe authors showed that wounds treated with e-SVF healed better than those treated with hyaluronic acid. In fact, after 9.7 weeks, patients treated with e-SVF underwent 97.9% ± 1.5% reepithelialisation compared to 87.8% ± 4.4% of the first control group (only hyaluronic acid; p < 0.05). Patients treated with PRP and fat grafting also showed an improvement in reepithelialisation; in fact after 9.7 weeks, they underwent a 97.8% ± 1.5% reepithelialisation compared to 89.1% ± 3.8% of the second control group (only PRP; p < 0.05). As reported e-SVF and PRP mixed with fat grafting were the two treatments evidencing improvement in the healing of patients post-traumatic extremity ulcers.ConclusionsThe results obtained proved the efficacy of these treatments, and the satisfaction of the patients confirmed the quality of the results.