Ancient split of major genetic lineages of European Black Pine: evidence from chloroplast <Emphasis>DNA</Emphasis>

The European Black Pine (Pinus nigra Arn.) has a long and complex history. Genetic distance and frequency analyses identified three differentiated genetic groups, which corresponded to three wide geographical areas: Westerns Mediterranean, Balkan Peninsula and Asia Minor. These groups shared common ancestors (14.75 and 10.72 Ma). The most recent splits occurred after the Messinian Salinity Crisis (4.37 Ma) and the Early–Middle Pleistocene Transitions (0.93 Ma). The posterior ancestral population size (Na) is 260,000–265,000 individuals. Each pool is further fragmented, with evidence of a phylogeographic structure (N _st  > G _st ) typically observed in some natural populations from the Western Mediterranean region and the Balkan Peninsula. The laboratory analysis was performed by fragment analysis—i.e. electrophoretic sizing of polymerase chain reaction fragments, combined with the sequencing analysis of 33 % of all individuals as a control. Intense sampling of chloroplast DNA polymorphisms (3154 individuals and 13 markers: SNPs and SSRs) over the full area of the species’ natural distribution indicated moderate among-population variability (G _st(nc) ≤ 0.177) in various parts of its range. These results indicate that the natural populations have long migration histories that differ from one another and that they have been strongly phylogeographically affected by complex patterns of isolation, speciation and fragmentation. Long and varying climatic fluctuations in the region of the principal genetic group have been the probable cause of different forest community associations with different successional patterns resulting in interglacial refugia vs. macro long-term refugia.     

Gonadal function in male mountain bikers

Some studies reported testicular disorders associated with biking in mountain cyclists, which include injuries, erectile dysfunction, and higher scrotal temperatures. But none of these studies evaluated gonadal function. Therefore, the aim of this study was to evaluate gonadal function in male mountain bikers. Twenty-two male professional mountain bikers and 30 healthy noncyclist controls were included in the study. The mean age and body mass index were similar in both groups. Fasting blood samples for the measurement of the levels of total testosterone (TT), sex-hormone binding globulin (SHBG), luteinizing hormone (LH), and follicle-stimulating hormone (FSH) were obtained from all study participants before any physical activity. In addition, because insulin sensitivity and leptin modulate gonadal function, the concentrations of insulin, glucose, and leptin were also measured in the same samples. Calculated free testosterone (cFT) and bioavailable testosterone (bioT) were calculated from SHBG and TT. Basal hormonal levels including insulin, leptin, LH, FSH, SHBG, TT, glucose, and homeostasis model assessment scores were similar between the groups. However, bioT and cFT levels were significantly lower (p ≤ 0.05) in the mountain bikers than those in the controls. Despite the lower mean testosterone levels in the study group, the levels of LH and FSH were similar to controls. Insulin and leptin do not contribute to lower testosterone levels. In conclusion, male mountain bikers have lower testosterone concentrations compared to controls. This alteration cannot solely be explained by testicular dysfunction. The etiology of lower testosterone levels in cyclists appears to be complex and requires further research. The influence of such a decline on the athlete's performance, quality of life, and muscle strength is not known as yet.     

Positive impact of levetiracetam on emotional learning and memory in naive mice

AimsThe effect of an antiepileptic drug on cognitive function is of primary importance with respect to the patient's quality of life. Levetiracetam (LEV) is a novel antiepileptic drug used to treat epilepsy, but its effects on spatial and emotional learning and memory are not yet well understood. The goal of our study was to establish the effects of LEV (17 and 54 mg/kg, intraperitoneally (IP)) on spatial memory retrieval in the Morris water maze test and on acquisition and memory formation in the passive avoidance (PA) test in naive mice.Main methodsThe subjects were adult male BALB/c mice. Spatial learning and memory was established with the Morris water maze (MWM) test. The ‘time spent in escape platforms quadrant’ and the ‘distance to platform’ analyses were measured using a video tracking system to determine spatial memory function. Emotional learning and memory were determined with a one-trial, step-through passive avoidance test.Key findingsIn the MWM test, LEV (17 and 54 mg/kg) neither affected the time spent in the target quadrant nor altered the distance to platform. Moreover, LEV had no effect on swim speed. In the PA task, LEV (17 and 54 mg/kg) significantly prolonged retention latency.SignificanceOur results indicate that LEV did not alter spatial memory retrieval in the MWM test, but it did show some ameliorating effects on acquisition and memory formation in the PA test in naive mice.     

Conformational changes mediate interleukin-10 receptor 2 (IL-10R2) binding to IL-10 and assembly of the signaling complex

Interleukin-10 receptor 2 (IL-10R2) is a critical component of the IL-10.IL-10R1.IL-10R2 complex which regulates IL-10-mediated immunomodulatory responses. The ternary IL-10 signaling complex is assembled in a sequential order with the IL-10.IL-10R1 interaction occurring first followed by engagement of the IL-10R2 chain. In this study we map the IL-10R2 binding site on IL-10 using surface plasmon resonance and cell-based assays. Critical IL-10R2 binding residues are located in helix A adjacent to the previously identified IL-10R1 recognition surface. Interestingly, IL-10R2 binding residues located in the N-terminal end of helix A exhibit large structural differences between unbound cIL-10 and cIL-10.IL-10R1 crystal structures. This suggests IL-10R1-induced conformational changes regulate IL-10R2 binding and assembly of the ternary IL-10.IL-10R1.IL-10R2 complex. The basic mechanistic features of the assembly process are likely shared by six additional class-2 cytokines (viral IL-10s, IL-22, IL-26, IL-28A, IL28B, and IL-29) to promote IL-10R2 binding to six additional receptor complexes. These studies highlight the importance of structure in regulating low affinity protein-protein interactions and IL-10 signal transduction.     

An unusual patient with hypercalciuria, recurrent nephrolithiasis, hypomagnesemia and G227R mutation of Paracellin-1. An unusual patient with hypercalciuria and hypomagnesemia unresponsive to thiazide diuretics

A 19-year-old female patient with hypercalciuria and recurrent nephrolithiasis/urinary tract infection unresponsive to thiazide type diuretics is presented. The patient first experienced nephrolithiasis at the age of 4 years. Afterwards, recurrent passages of stones and urinary tract infection occurred. On diagnostic evaluation at the age of 19 years, she also had hypocitraturia and hypomagnesemia. Her serum calcium concentrations were near the lower limit of normal (8.5-8.8 mg/dl; normal range: 8.5-10.5), her serum magnesium concentrations were 1.15-1.24 mg/dl (normal range: 1.4-2.5) and urinary calcium excretion was 900 mg/24 h. PTH concentrations were increased (110-156 pg/ml; normal range: 10-65). We tried to treat the patient with hydrochlorothiazide at a dose of 50 mg/day. During treatment with thiazide diuretics, PTH concentration remained high and the patient had recurrent urinary tract infections and passages of stones. Serum magnesium concentration did not normalize even under the parenteral magnesium infusion. Her mother had a history of nephrolithiasis 20 years ago. Severe hypomagnesemia in association with hypercalciuria/urinary stones is reported as a rare autosomal recessive disorder caused by impaired reabsorption of magnesium and calcium in the thick assending limp of Henle's loop. Recent studies showed that mutations in the CLDN16 gene encoding paracellin-1 cause the disorder. In exon 4, a homozygous nucleotide exchange (G679C) was identified for the patient. This results in a point mutation at position Glycine227, which is replaced by an Arginine residue (G227R). The mother was heterozygous for this mutation. G227 is located in the fourth transmembrane domain and is highly conserved in the claudin gene family. This case indicates the pathogenetic role of paracellin-1 mutation in familial hypomagnesemia with hypercalciuria and nephrocalcinosis and further underlines the risk of stone formation in heterozygous mutation carriers.     

Antioxidant defense system and cadmium uptake in barley genotypes differing in cadmium tolerance

Using two barley (Hordeum vulgare) cultivars (cvs. Tokak and Hamidiye) nutrient solution experiments were conducted in order to study the genotypic variation in tolerance to Cd toxicity based on (i) development of leaf symptoms, (ii) decreases in dry matter production, (iii) Cd concentration and (iv) changes in antioxidative defense system in leaves (i.e., superoxide dismutase, ascorbate peroxidase, glutathione reductase, catalase, ascorbic acid and non-protein SH-groups). Plants were grown in nutrient solution under controlled environmental conditions, and subjected to increasing concentrations of Cd (0, 15, 30, 60 and 120 micromol/L Cd) for different time periods. Of the barley cultivars Hamidiye was particularly sensitive to Cd as judged by the severity and earlier development of Cd toxicity symptoms on leaves. Within 48 h of Cd application Hamidiye rapidly developed severe leaf Cd toxicity symptoms whereas in Tokak the leaf symptoms appeared only slightly. Hamidiye also tended to show more decrease in growth caused by Cd supply when compared to Tokak. The differences in sensitivity to Cd between Tokak and Hamidiye were not related to Cd concentrations in roots and shoots or Cd accumulation per plant. With the exception of catalase, activities of the enzymes involved in detoxification of reactive oxygen species (ROS) were markedly enhanced in Hamidiye by increasing Cd supply. By contrast, in Tokak there was either only a slight increase or no change in the activities of the antioxidative enzymes. Similarly, levels of ascorbic acid and especially non-protein SH-groups were increased in Hamidiye by Cd supply, but not affected in Tokak. The results indicate the existence of a large genotypic variation between barley cultivars for Cd tolerance. The differential Cd tolerance found in the barley cultivars was not related to uptake or accumulation of Cd in plants, indicating importance of internal mechanisms in expression of differential Cd tolerance in barley. As a response to increasing Cd supply particular increases in antioxidative mechanisms in the Cd-sensitive barley cultivar Hamidiye suggest that the high Cd sensitivity of Hamidiye is related to enhanced production and oxidative damage of ROS.     

The possibility of useful usage of biodegradation products of sunflower plants

Heads of sunflower (Helianthus annuus L.) were first biodegraded at 55 degrees C by their microflora. Biodegradation products of sunflower heads (BPSH) were analyzed. They were found to contain 9.77% dry matter, 3.98% total ash, 3.18% crude protein and 5.75% total organic matter. BOD load was determined as 4.80 g/100 g. Subsequently, the effects of BPSH at various concentrations (1.0%, 2.5%, 10% and 100%) on the seed germination and some growth parameters of Phaseolus vulgaris L., Cicer arietinum L. and Triticum vulgare L. were investigated. The percentages of seed germination and germination index of seeds were similar between the control and 1.0% and 2.5% BPSH groups, but these values decreased at higher concentrations. On the other hand, growth of the seedlings gradually increased up to a concentration of 10% BPSH and decreased at 100% concentration. As a result, at concentrations up to 10% the product was found to be beneficial for growth of plants.     

Alpha-Tocopherol Decreases Iron-Induced Hippocampal and Nigral Neuron Loss

There are many studies about iron-induced neuronal hyperactivity and oxidative stress. Some reports also showed that iron levels rise in the brain in some neurodegenerative diseases such as Parkinson’s (PD) and Alzheimer’s disease (AD). It has been suggested that excessive iron level increases oxidative stress and causes neuronal death. Tocopherols act as a free radical scavenger when phenoxylic head group encounters a free radical. We have aimed to identify the effect of α-tocopherol (Vitamin E) on iron-induced neurotoxicity. For this reason, rats were divided into three groups as control, iron, and iron + α-tocopherol groups. Iron chloride (200 mM in 2.5 μl volume) was injected into brain ventricle of iron and iron + α-tocopherol group rats. Same volume of saline (2.5 μl) was given to the rats belonging to control group. Rats of iron + α-tocopherol group received intraperitoneally (i.p.) α-tocopherol (100 mg/kg/day) for 10 days. After 10 days, rats were perfused intracardially under deep urethane anesthesia. Removed brains were processed using standard histological techniques. The numbers of neurons in hippocampus and substantia nigra of all rats were estimated by stereological techniques. Results of present study show that α-tocopherol decreased hippocampal and nigral neuron loss from 51.7 to 12.1% and 41.6 to 17.8%, respectively. Findings of the present study suggest that α-tocopherol may have neuroprotective effects against iron-induced hippocampal and nigral neurotoxicity and it may have a therapeutic significance for neurodegenerative diseases involved iron.