Evaluation of the androgenic competence of 66 wild Turkish Vaccaria hispanica (Mill.) Rauschert genotypes through microspore culture

One of the most remarkable natural plants is Vaccaria hispanica (Mill.) Rauschert, which has a high economic, medicinal and industrial potential due to its valuable compounds. However, it is mostly an underused plant worldwide. To implement doubled haploid technology in plant breeding programs and exploit its potential, first knowing the particulars of the species is necessary. This study was aimed to explore the androgenic potential of different wild Turkish V. hispanica genotypes collected from different Turkish regions, as a starting point to identify bottlenecks to solve in future studies. As to induction of microspore embryogenesis, nearly all of them responded, with efficiencies reaching 300 embryos/100 buds in some cases. However, we also found three main bottlenecks. First, the presence of foam-producing saponins in flowers prevented an efficient isolation of microspores. Second, embryos showed a reduced ability to germinate. Third, a dense network of hairy roots prevented the formation of a true, fully functional root system. Together, these drawbacks led to the production of very few DH plants. The presence of rhizogenic endophytes may be the cause of most of these problems, which opens the door for possible solutions.

     

Preventive role of gallic acid on hepatic ischemia and reperfusion injury in rats

There is little information about the hepatoprotective effects of gallic acid against ischemia–reperfusion (I/R) damage. Animals were subjected to I/R. Gallic acid at doses of 50 and 100 mg/kg body weight (bw) were injected as a single dose prior to ischemia. Liver tissue homogenates were used for the measurement of malondialdehyde (MDA), catalase (CAT) and glutathione peroxidase (GPx) levels. At the same time alanine aminotransferase (ALT), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) were assayed in serum samples and compared statistically. While the ALT, AST, LDH activities and MDA levels were significantly increased, CAT and GPx activities significantly decreased in only I/R-induced control rats compared to normal control rats (P < 0.05). Treatment with gallic acid at a dose of 100 mg/kg bw significantly decreased the ALT, AST, LDH activities and MDA levels, and markedly increased activities of CAT and GPx in tissue homogenates compared to I/R-induced rats with no treatment group (P < 0.05). In oxidative stress generated by hepatic ischemia–reperfusion, gallic acid contributes partially an alteration in the delicate balance between the scavenging capacity of antioxidant defense systems and free radicals in favour of the antioxidant defense systems in the body.     

RNA tertiary interactions mediate native collapse of a bacterial group I ribozyme

Large RNAs collapse into compact intermediates in the presence of counterions before folding to the native state. We previously found that collapse of a bacterial group I ribozyme correlates with the formation of helices within the ribozyme core, but occurs at Mg2+ concentrations too low to support stable tertiary structure and catalytic activity. Here, using small-angle X-ray scattering, we show that Mg2+-induced collapse is a cooperative folding transition that can be fit by a two-state model. The Mg2+ dependence of collapse is similar to the Mg2+ dependence of helix assembly measured by partial ribonuclease T1 digestion and of an unfolding transition measured by UV hypochromicity. The correspondence between multiple probes of RNA structure further supports a two-state model. A mutation that disrupts tertiary contacts between the L9 tetraloop and its helical receptor destabilized the compact state by 0.8 kcal/mol, while mutations in the central triplex were less destabilizing. These results show that native tertiary interactions stabilize the compact folding intermediates under conditions in which the RNA backbone remains accessible to solvent.     

Nickel resistance in fission yeast associated with the magnesium transport system

We isolated and characterized a nickel (Ni²⁺)-resistant mutant (GA1) of Schizosaccharomyces pombe. This mutant strain displayed resistance to both Ni²⁺ and Zn²⁺, but not to Cd²⁺, Co²⁺, and Cu²⁺. The growth rate of GA1 increased proportionally with increasing Mg²⁺ concentrations until 50 mM Mg²⁺. The GA1 mutation phenotype suggests a defect in Mg²⁺ uptake. Sequence analysis of the GA1 open reading frame (ORF) O13779, which is homologous to the prokaryotic and eukaryotic CorA Mg²⁺ transport systems, revealed a point mutation at codon 153 (ccc to acc) resulting in a Pro 153Thr substitution in the N-terminus of the CorA domain. Our results provide novel genetic information about Ni²⁺ resistance in fission yeast. Specifically, that reducing Mg²⁺ influx through the CorA Mg²⁺ transport membrane protein confers Ni²⁺ resistance in S. pombe. We also report that Ni²⁺ ion detoxification of the fission yeast is related to histidine metabolism and pH.     

Neuronal PTP1B regulates body weight, adiposity and leptin action

Obesity is a major health problem and a risk factor for type 2 diabetes. Leptin, an adipocyte-secreted hormone, acts on the hypothalamus to inhibit food intake and increase energy expenditure. Most obese individuals develop hyperleptinemia and leptin resistance, limiting the therapeutic efficacy of exogenously administered leptin. Mice lacking the tyrosine phosphatase PTP1B are protected from diet-induced obesity and are hypersensitive to leptin, but the site and mechanism for these effects remain controversial. We generated tissue-specific PTP1B knockout (Ptpn1(-/-)) mice. Neuronal Ptpn1(-/-) mice have reduced weight and adiposity, and increased activity and energy expenditure. In contrast, adipose PTP1B deficiency increases body weight, whereas PTP1B deletion in muscle or liver does not affect weight. Neuronal Ptpn1(-/-) mice are hypersensitive to leptin, despite paradoxically elevated leptin levels, and show improved glucose homeostasis. Thus, PTP1B regulates body mass and adiposity primarily through actions in the brain. Furthermore, neuronal PTP1B regulates adipocyte leptin production and probably is essential for the development of leptin resistance.     

Evaluation of the JAK2-V617F gene mutation in Turkish patients with essential thrombocythemia and polycythemia vera

An activating mutation of Janus kinase 2 (JAK2-V617F) was previously described in chronic myeloproliferative disorders (MPD). In previously published studies, the frequency of the JAK2-V617F mutation was determined to be 80-90 % for patients with polycythemia vera (PV) and 40-70 % for essential thrombocythemia (ET). In this study, we analyzed the relationship between the JAK2-V617F mutation and clinical-hematological parameters in Turkish patients with MPD and compared these findings with published studies from other geographic regions. A total of 148 patients were studied; of which, 70 were diagnosed with PV and 78 with ET. The mutation status of JAK2 was determined using a tetra-primer polymerase chain reaction. We found that 80 % of the PV group and 42 % of the ET group were positive for the JAK2-V617F mutation. When all patients were analyzed, the levels of white blood cells, hemoglobin and splenomegaly were significantly different in patients with the JAK2-V617F mutation (p < 0.05). To our knowledge, this study is the first to evaluate the relationship between MPD and JAK2-V617F in Turkish patients. The JAK2-V617F mutation is frequently detected in the Turkish patients with MPD, and especially in patients with PV. Hence, it would be useful to include JAK2 mutation screening in the initial evaluation of patients suspected to have MPD.     

Takayasu's arteritis is associated with HLA-B*52, but not with HLA-B*51, in Turkey

Introduction

HLA-B*51 and HLA-B*52 are two close human leukocyte antigen (HLA) allele groups with minor amino acid differences. However, they are associated with two different vasculitides (HLA-B*51 in Behçet's disease and HLA-B*52 in Takayasu's arteritis (TAK)) and with major clinical and immunological differences. In this study, we aimed to screen a large cohort of TAK patients from Turkey for the presence of HLA-B*51 and HLA-B*52 as susceptibility and severity factors.

Methods

TAK patients (n = 330) followed at a total of 15 centers were included in the study. The mean age of the patients was 37.8 years, and 86% were women. DNA samples from the patients and healthy controls (HC; n = 210) were isolated, and the presence of HLA-B*51 or HLA-B*52 was screened for by using PCR with sequence-specific primers.

Results

We found a significant association of HLA-B*52 with TAK (20.9% vs HC = 6.7%, P = 0.000, OR = 3.7, 95% CI = 2.02 to 6.77). The distribution of HLA-B*51 did not differ between TAK patients and HCs (22.7% vs 24.8%, OR = 0.9, 95% CI = 0.60 to 1.34). The presence of HLA-B*52 decreased in late-onset patients (> 40 years of age; 12.0%, P = 0.024, OR = 0.43, 95% CI = 0.20 to 0.91). Patients with angiographic type I disease with limited aortic involvement also had a lower presence of HLA-B*52 compared to those with all other disease subtypes (13.1% vs 26%, P = 0.005, OR = 0.43, 95% CI = 0.23 to 0.78).

Conclusions

In this study, the previously reported association of TAK with HLA-B*52 in other populations was confirmed in patients from Turkey. The functional relevance of HLA-B*52 in TAK pathogenesis needs to be explored further.