Induction of fibronectin mRNA by urokinase- and tissue-type plasminogen activator in human skin fibroblasts: differential role of u-PA and t-PA at the fibronectin protein level

Plasminogen activators of the urokinase- and tissue-type and fetal calf serum (u-PA, t-PA, FCS) exert their mitogenic effect on quiescent human dermal fibroblasts and modulate the mRNA expression of cell-cycle related genes. The present study deals with the effects of PAs on the expression of fibronectin (FN), a heterodimeric extracellular matrix (ECM) protein that can be modulated in different ways by various mitogens. The kinetics of FN gene response was examined in quiescent fibroblasts upon PA stimulation (30 min -24 h). The results obtained evidenced that: (i) all mitogens tested (u-PA, t-PA and FCS) led to an increase of FN mRNA expression in early G1, as shown by the analysis of two sequences, III-9, common to all FN mRNAs, and EDA+, present only in the EDA+FN isoform; (ii) the kinetic profiles of FN mRNA stimulation were comparable for the three mitogens, although the effects on the FN-ECM assembly were distinct; (iii) t-PA and FCS led to FN assembly in the ECM, which was absent or decreased in u-PA-treated cultures. Immunobiochemical analysis of total FN and EDA+ FN showed that FN induced by t-PA was mainly dimeric (450-500 kDa), whereas FN induced by u-PA was mainly monomeric (230-250 kDa). These differences are probably due to the differential enzymatic action of t-PA and u-PA on FN, which might be related to a differential role of the two PAs in several physiopathological conditions.     

Optimizing Controlled Environment Assessment of Levels of Resistance to Yam Anthracnose Disease Using Tissue Culture-derived Whole Plants

Studies were conducted to determine the timing and frequency of disease assessment required to effectively identify levels of resistance to yam anthracnose using tissue culture‐derived whole plant inoculation assay. The effects of inoculation methods (paint brush and spray), and disease scoring methods [individual leaf area (ILA) and whole plant area (WPA)] were also assessed. Spray inoculation resulted in rapid infection and higher variations among yam genotypes, leading to earlier discrimination of genotypes than with the paintbrush method. Both the ILA and WPA scoring methods showed variation among yam genotypes, and association between the two methods gave a high positive correlation (r > 0.90). However, the WPA was faster and had the advantage of detecting differences in reactions of yam genotypes to less aggressive pathogen isolates to which the ILA method showed no variation. A single disease evaluation at 7 days after inoculation was as good as the area under the disease progress curve (AUDPC) and the disease progress rate (R_d) derived from multiple evaluations. However, a significant time–genotype interaction, suggests a need for more than a single assessment for effective comparison of genotypes. AUDPC derived from two assessments (5 and 7 DAI) was better than AUDPC from three assessments (5, 7 and 9 DAI) in separating genotypes reactions to a less aggressive pathogen isolate. This study showed that the use of spray inoculation method, the WPA scoring method, and AUDPC derived from two assessments (5 and 7 DAI) provided best conditions for evaluating yam genotypes for levels of anthracnose resistance with the tissue culture‐derived whole plant assay.     

Response of hepatic metallothionein to iron administration

Female broiler chicks receiving an ip injection of Fe (10 mg/kg bw) were found to have a greatly increased level of hepatic metallothionein. The increase in metallothionein was not correlated with changes in serum corticosterone. Attempts to vary serum corticosterone levels by feeding metyrapone, an 11-β steroid hydroxylase inhibitor, were unsuccessful.     

Straightforward hit identification approach in fragment-based discovery of bromodomain-containing protein 4 (BRD4) inhibitors

A combination approach of a fragment screening and “SAR by catalog” was used for the discovery of bromodomain-containing protein 4 (BRD4) inhibitors. Initial screening of 3695-fragment library against bromodomain 1 of BRD4 using thermal shift assay (TSA), followed by initial hit validation, resulted in 73 fragment hits, which were used to construct a follow-up library selected from available screening collection. Additionally, analogs of inactive fragments, as well as a set of randomly selected compounds were also prepared (3?×?3200 compounds in total). Screening of the resulting sets using TSA, followed by re-testing at several concentrations, counter-screen, and TR-FRET assay resulted in 18 confirmed hits. Compounds derived from the initial fragment set showed better hit rate as compared to the other two sets. Finally, building dose-response curves revealed three compounds with IC₅₀?=?1.9–7.4?μM. For these compounds, binding sites and conformations in the BRD4 (4UYD) have been determined by docking.     

Effects of heavy barbell hip thrust vs back squat on subsequent sprint performance in rugby players

The objective of this research was to compare the effect of Post-Activation Performance Enhancement (PAPE) exerted on the back squat (BS) versus the barbell hip thrust (HT) on the sprint performance (5- and 10-m). 17 male amateur rugby players participated in the study (age 22.14 ± 2.52 years; body mass 81.06 ± 9.6 kg; height 1.78 ± 0.05 m). All participants performed a dynamic maximum strength test (3RM) in BS and HT at maximum speed. Two randomized sessions were performed inducing PAPE using BS or HT trough three series with three repetitions at 85% 1RM eight minutes before the sprint tests. An ANOVA of repeated measurement, found no differences in the time for 5-m (F = 0.398, P = 0.537, η²p = 0.024) or 10-m (F = 2.589, P = 0.127, η²p = 0.139). There were no significant differences in the Protocol effect between HT and BS in 5-m or 10-m (F = 2.963, P = 0.104, η²p = 0.156 and F = 1.472, P = 0.243 η²p = 0.084, respectively). There were also no differences in the Time x Protocol interaction at 5-m (F = 0.001, P = 0.976, η²p < 0.001) or 10-m (F = 4.174, P = 0.058, η²p = 0.207). The effect size obtained in the results of the sprint tests was small in both exercises (ES < 0.2). None of the BS or HT exercises performed with heavy load induced a significant PAPE phenomenon on the ability to sprint in rugby players.     

Quenching of chlorophyll triplet states by carotenoids in algal light-harvesting complexes related to fucoxanthin-chlorophyll protein

Photosynthesis Research - We have used time-resolved absorption and fluorescence spectroscopy with nanosecond resolution to study triplet energy transfer from chlorophylls to carotenoids in a...     

Blast-Associated Shock Waves Result in Increased Brain Vascular Leakage and Elevated ROS Levels in a Rat Model of Traumatic Brain Injury

Blast-associated shock wave-induced traumatic brain injury (bTBI) remains a persistent risk for armed forces worldwide, yet its detailed pathophysiology remains to be fully investigated. In this study, we have designed and characterized a laboratory-scale shock tube to develop a rodent model of bTBI. Our blast tube, driven by a mixture of oxygen and acetylene, effectively generates blast overpressures of 20–130 psi, with pressure-time profiles similar to those of free-field blast waves. We tested our shock tube for brain injury response to various blast wave conditions in rats. The results show that blast waves cause diffuse vascular brain damage, as determined using a sensitive optical imaging method based on the fluorescence signal of Evans Blue dye extravasation developed in our laboratory. Vascular leakage increased with increasing blast overpressures and mapping of the brain slices for optical signal intensity indicated nonhomogeneous damage to the cerebral vasculature. We confirmed vascular leakage due to disruption in the blood-brain barrier (BBB) integrity following blast exposure. Reactive oxygen species (ROS) levels in the brain also increased with increasing blast pressures and with time post-blast wave exposure. Immunohistochemical analysis of the brain sections analyzed at different time points post blast exposure demonstrated astrocytosis and cell apoptosis, confirming sustained neuronal injury response. The main advantages of our shock-tube design are minimal jet effect and no requirement for specialized equipment or facilities, and effectively generate blast-associated shock waves that are relevant to battle-field conditions. Overall data suggest that increased oxidative stress and BBB disruption could be the crucial factors in the propagation and spread of neuronal degeneration following blast injury. Further studies are required to determine the interplay between increased ROS activity and BBB disruption to develop effective therapeutic strategies that can prevent the resulting cascade of neurodegeneration.