Processing of DNA lesions by archaeal DNA polymerases from Sulfolobus solfataricus

Spontaneous damage to DNA as a result of deamination, oxidation and depurination is greatly accelerated at high temperatures. Hyperthermophilic microorganisms constantly exposed to temperatures exceeding 80°C are endowed with powerful DNA repair mechanisms to maintain genome stability. Of particular interest is the processing of DNA lesions during replication, which can result in fixed mutations. The hyperthermophilic crenarchaeon Sulfolobus solfataricus has two functional DNA polymerases, PolB1 and PolY1. We have found that the replicative DNA polymerase PolB1 specifically recognizes the presence of the deaminated bases hypoxanthine and uracil in the template by stalling DNA polymerization 3–4 bases upstream of these lesions and strongly associates with oligonucleotides containing them. PolB1 also stops at 8-oxoguanine and is unable to bypass an abasic site in the template. PolY1 belongs to the family of lesion bypass DNA polymerases and readily bypasses hypoxanthine, uracil and 8-oxoguanine, but not an abasic site, in the template. The specific recognition of deaminated bases by PolB1 may represent an initial step in their repair while PolY1 may be involved in damage tolerance at the replication fork. Additionally, we reveal that the deaminated bases can be introduced into DNA enzymatically, since both PolB1 and PolY1 are able to incorporate the aberrant DNA precursors dUTP and dITP.     

Basic Analysis of the Cerebrospinal Fluid: An Important Framework for Laboratory Diagnostics of the Impairment of the Central Nervous System

Laboratory analysis of basic cerebrospinal fluid (CSF) parameters is considered as essential for any CSF evaluation. It can provide rapidly very valuable information about the status of the central nervous system (CNS). Our retrospective study evaluated parameters of basic CSF analysis in cases of either infectious or non-infectious CNS involvement. Neutrophils are effector cells of innate immunity. Predominance of neutrophils was found in 98.2% of patients with purulent inflammation in CNS. Lymphocytes are cellular substrate of adaptive immunity. We found their predominance in 94.8% of patients with multiple sclerosis (MS), 66.7% of patients with tick-borne encephalitis (TBE), 92.2% of patients with neuroborreliosis, 83.3% of patients with inflammatory response with oxidative burst of macrophages in CNS and 75.0% of patients with malignant infiltration of meninges (MIM). The simultaneous assessment of aerobic and anaerobic metabolism in CSF using the coefficient of energy balance (KEB) allows us to specify the type of inflammation in CNS. We found predominantly aerobic metabolism (KEB > 28.0) in 100.0% CSF of patients with normal CSF findings and in 92.8% CSF of patients with MS. Predominant faintly anaerobic metabolism (28.0 > KEB > 20.0) in CSF was found in 71.8% patients with TBE and in 64.7% patients with neuroborreliosis. Strong anaerobic metabolism (KEB < 10.0) was found in the CSF of 99.1% patients with purulent inflammation, 100.0% patients with inflammatory response with oxidative burst of macrophages and in 80.6% patients with MIM. Joint evaluation of basic CSF parameters provides sufficient information about the immune response in the CSF compartment for rapid and reliable diagnosis of CNS involvement.     

Elite young soccer players have smaller inter-limb asymmetry and better body composition than non-elite players

Body composition (BC) and inter-limb anthropometric asymmetries (LA) may influence the physical performance of soccer players. This study aimed to determine differences in BC and LA among soccer across four performance levels. The study involved 110 male soccer players participating in Czech senior teams who were grouped into four different performance levels (i.e. G1: national team, G2: 1^st division, G3: 2^nd division, G4: 3^rd division). The following BC and LA parameters were compared among groups: body height, body mass, absolute fat-free mass, relative fat-free mass (FFMrel), percentage of fat mass (FM), total body water (TBW), intracellular water (ICW), extracellular water (ECW), phase angle, and bilateral muscle mass differences in the upper and lower extremities. Significant differences were observed in BC parameters among all groups (λ = 0.06, F75,246 = 5.38, p = 0.01, η_p² = 0.62). High-performance players (i.e. G1, G2) had significantly (p < 0.01) lower FM than lower performance players (i.e. G3, G4). The lowest values of FFMrel, relative TBW, relative ICW and ECW were detected in the lowest-performance players (i.e. G4). Significantly lower bilateral muscle mass differences were detected in G1 players (2.71 ± 1.26%; p < 0.01) compared with G4 players (3.95 ± 1.17%). G1 and G2 players had a higher proportion of muscle mass in the torso (p < 0.01) and upper limbs than G3 and G4 (p < 0.01). Elite and high-performance players have better BC and lower inter-limb anthropometric asymmetries compared with low-performance level players.     

The effects of local and landscape-scale habitat characteristics and prey availability on corridor use by carnivores: A comparison of two contrasting farmlands

Corridors are thought to reduce the negative biological effects of habitat loss and fragmentation by providing connectivity and suitable habitat for many species, including carnivores. Although corridor structure maintenance is considered to be an essential tool for carnivore conservation in a human-dominated landscape, surprisingly little is known about the effects of different factors at various spatial scales. The main aim of this study was to determine how local and landscape-scale habitat characteristics and prey availability influence the corridor use by carnivores in a Central European agricultural landscape. Moreover we investigated carnivore corridor occurrence in two contrasting landscapes that differ in level of habitat loss and fragmentation to evaluate relative effect of species-specific response to regional context. Results show that the availability of principal prey (small mammals) was the most crucial factor affecting carnivore corridor use. Other important factors influencing corridor use were corridor width (positive), proportion of shrubs (positive) and presence of local, low-traffic, roads (positive). Single species models revealed interspecific and area-specific differences in carnivore preference at both spatial scales. Our findings confirm the general importance of multi-level approach to evaluating species-specific habitat requirements as a crucial tool for determining suitable methods for carnivore efficient conservation in human-dominated agricultural landscape.     

The biogeography of naturalization in alien plants

Aim  This paper reviews the main geographical determinants of naturalization in plants.
Location  Global.
Methods  Comparative studies of large data sets of alien floras are the main source of information on global patterns of naturalization.
Results  Temperate mainland regions are more invaded than tropical mainland regions but there seems to be no difference in invasibility of temperate and tropical islands. Islands are more invaded than the mainland. The number of naturalized species in temperate regions decreases with latitude and their geographical ranges increase with latitude. The number of naturalized species on islands increases with temperature. Naturalized species contribute to floristic homogenization, but the phenomenon is scale-dependent.
Main conclusions  Some robust patterns are evident from currently available data, but further research is needed on several aspects to advance our understanding of the biogeography of naturalization of alien plants. For example, measures of propagule pressure are needed to determine the invasibility of communities/ecosystems/regions. The patterns discussed in this paper are derived largely from numbers and proportions of naturalized species, and little is known about the proportion of introduced species that become naturalized. Further insights on naturalization rates, i.e. the proportion of aliens that successfully naturalize within regions, and on geographical and other determinants of its variation would provide us with better understanding of the invasion process. Comparative studies, and resulting generalizations, are almost exclusively based on numbers of species, but alien species differ in their impact on native biodiversity and ecosystem processes.     

Allogeneic and autogenous transplantations of MSCs in treatment of the physeal bone bridge in rabbits

Background

Serum and high ionic strength solutions constitute important barriers to cationic lipid-mediated intravenous gene transfer. Preparation or incubation of lipoplexes in these media results in alteration of their biophysical properties, generally leading to a decrease in transfection efficiency. Accurate quantification of these changes is of paramount importance for the success of lipoplex-mediated gene transfer in vivo.

Results

In this work, a novel time-resolved fluorescence resonance energy transfer (FRET) methodology was used to monitor lipoplex structural changes in the presence of phosphate-buffered saline solution (PBS) and fetal bovine serum. 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP)/pDNA lipoplexes, prepared in high and low ionic strength solutions, are compared in terms of complexation efficiency. Lipoplexes prepared in PBS show lower complexation efficiencies when compared to lipoplexes prepared in low ionic strength buffer followed by addition of PBS. Moreover, when serum is added to the referred formulation no significant effect on the complexation efficiency was observed. In physiological saline solutions and serum, a multilamellar arrangement of the lipoplexes is maintained, with reduced spacing distances between the FRET probes, relative to those in low ionic strength medium.

Conclusion

The time-resolved FRET methodology described in this work allowed us to monitor stability and characterize quantitatively the structural changes (variations in interchromophore spacing distances and complexation efficiencies) undergone by DOTAP/DNA complexes in high ionic strength solutions and in presence of serum, as well as to determine the minimum amount of potentially cytotoxic cationic lipid necessary for complete coverage of DNA. This constitutes essential information regarding thoughtful design of future in vivo applications.