Molecular markers for leaf rust resistance genes in wheat

Over 100 genes of resistance to rust fungi: Puccinia recondita f. sp. tritici, (47 Lr - leaf rust genes), P. striiformis (18 Yr - yellow rust genes) and P. graminis f. sp. tritici (41 Sr - stripe rust genes) have been identified in wheat (Triticum aestivum L.) and its wild relatives according to recent papers. Sixteen Lr resistance genes have been mapped using restriction fragments length polymorphism (RFLP) markers on wheat chromosomes. More than ten Lr genes can be identified in breeding materials by sequence tagged site (STS) specific markers. Gene Lrk 10, closely linked to gene Lr 10, has been cloned and its function recognized. Available markers are presented in this review. The STS, cleaved amplified polymorphic sequence (CAPS) and sequence characterized amplified regions (SCAR) markers found in the literature should be verified using Triticum spp. with different genetic background. Simple sequence repeats (SSR) markers for Lr resistance genes are now also available.     

Genetic and nongenetic factors influencing callus induction inMiscanthus sinensis (Anderss.) anther cultures

Miscanthus sinensis is a promising species for biomass production. Influences of genetic and nongenetic factors on androgenesis induction efficiency were investigated. This is the first report on successful induction of pollen-derived callus inM. sinensis. The callus yield was strongly affected by genotype. A beneficial influence of cold pretreatment of spikes on androgenesis induction was observed. The highest yield of calli was obtained in cultures on a modified C17 medium. The results suggest that the high callus yield might be caused by the late culture initiation. The beginning of anther culture at the end of the flowering season caused a 17-fold increase in callus yield, in comparison to culture initiated at the height of the flowering season (August). It is likely, however, that the efficiency of androgenesis induction in the case ofM. sinensis anther culture beginning in October could be related to a positive influence of growing donor plants in conditions of cooler and shorter day, i.e. 11-h day with temperature around 11°C and 13-h night with temperature around 5°C. Results of this study can significantly support the development of effective methods ofM. sinensis haploidization, which could be used in crop improvement by breeding.     

Numerical simulation for a neurotransmitter transport model in the axon terminal of a presynaptic neuron

Neurotransmitters in the terminal bouton of a presynaptic neuron are stored in vesicles, which diffuse in the cytoplasm and, after a stimulation signal is received, fuse with the membrane and release its contents into the synaptic cleft. It is commonly assumed that vesicles belong to three pools whose content is gradually exploited during the stimulation. This article presents a model that relies on the assumption that the release ability is associated with the vesicle location in the bouton. As a modeling tool, partial differential equations are chosen as they allow one to express the continuous dependence of the unknown vesicle concentration on both the time and space variables. The model represents the synthesis, concentration-gradient-driven diffusion, and accumulation of vesicles as well as the release of neuroactive substances into the cleft. An initial and boundary value problem is numerically solved using the finite element method (FEM) and the simulation results are presented and discussed. Simulations were run for various assumptions concerning the parameters that govern the synthesis and diffusion processes. The obtained results are shown to be consistent with those obtained for a compartment model based on ordinary differential equations. Such studies can be helpful in gaining a deeper understanding of synaptic processes including physiological pathologies. Furthermore, such mathematical models can be useful for estimating the biological parameters that are included in a model and are hard or impossible to measure directly.     

Mutations in TMEM76* cause mucopolysaccharidosis IIIC (Sanfilippo C syndrome)

Mucopolysaccharidosis IIIC (MPS IIIC, or Sanfilippo C syndrome) is a lysosomal storage disorder caused by the inherited deficiency of the lysosomal membrane enzyme acetyl-coenzyme A: alpha -glucosaminide N-acetyltransferase (N-acetyltransferase), which leads to impaired degradation of heparan sulfate. We report the narrowing of the candidate region to a 2.6-cM interval between D8S1051 and D8S1831 and the identification of the transmembrane protein 76 gene (TMEM76), which encodes a 73-kDa protein with predicted multiple transmembrane domains and glycosylation sites, as the gene that causes MPS IIIC when it is mutated. Four nonsense mutations, 3 frameshift mutations due to deletions or a duplication, 6 splice-site mutations, and 14 missense mutations were identified among 30 probands with MPS IIIC. Functional expression of human TMEM76 and the mouse ortholog demonstrates that it is the gene that encodes the lysosomal N-acetyltransferase and suggests that this enzyme belongs to a new structural class of proteins that transport the activated acetyl residues across the cell membrane.     

Carbonic anhydrase inhibitors. Selective inhibition of human tumor-associated isozymes IX and XII and cytosolic isozymes I and II with some substituted-2-mercapto-benzenesulfonamides

A series of 2-mercapto-substituted-benzenesulfonamides has been prepared by a unique two-step procedure starting from the corresponding 2-chloro-substituted benzenesulfonamides. Compounds bearing an unsubstituted mercapto group and the corresponding S-benzoyl derivatives were investigated as inhibitors of four isoforms of the zinc enzyme carbonic anhydrase (CA, EC 4.2.1.1), i.e., the cytosolic, ubiquitous isozymes CA I and II, as well as the transmembrane, tumor associated isozymes CA IX and XII. These derivatives were medium potency hCA I inhibitors (K(I)s in the range of 1.5-5.7 microM), two derivatives were strong hCA II inhibitors (K(I)s in the range of 15-16 nM), whereas the others showed weak activity. These compounds inhibited hCA IX with inhibition constants in the range 160-1950 nM and hCA XII with inhibition constants in the range 1.2-413 nM. Some of these derivatives showed a certain degree of selectivity for inhibition of the tumor-associated over the cytosolic isoforms, being thus interesting leads for the development of potentially novel applications in the management of hypoxic tumors which overexpress CA IX and XII.     

Cytogenetic effect of prolonged in vitro exposure of <Emphasis Type="Italic">Allium cepa</Emphasis> L. root meristem cells to salt stress

Salt stress severely affects plant growth and regulation; however knowledge about its effect on cytological changes is limited. In this report, studies were carried out to reveal the morphological and cytogenetic responses of the Allium cepa roots after prolonged (7, 14, 20 days) exposure to salt stress in tissue culture conditions. Roots of plants were treated with different concentrations (100, 200, 300 mM) of NaCl and KCl added to the culture medium. Both salts caused root growth reduction and showed cytotoxic effect reflected in reduction of root tip cells mitotic activity and increase of different abnormalities such as chromosome breaks and bridges and formation of micronuclei. This experiment showed differences of the action of excessive amounts of both tested salts at the cellular level, as KCl induced higher frequencies of abnormalities during cell divisions, whereas NaCl showed more mitodepressive effect and more frequently led to the root meristem cell death.     

The effects of percutaneous transluminal coronary intervention on biomarkers of oxidative stress in the erythrocytes of elderly male patients

Objectives: Oxidative stress plays a key role in the pathogenesis of coronary artery disease. The aim of this study was to compare the effects of percutaneous transluminal coronary angioplasty (PTCA) and elective coronary angiography (EC) on erythrocytic antioxidant defense in elderly male patients.

Methods: Twenty-three stable angina pectoris (SAP) patients undergoing PTCA and 18 patients with ischemic symptoms scheduled to undergo diagnostic EC were included in the study. The concentrations of malondialdehyde (MDA) and reduced glutathione (GSH) and the activities of Zn,Cu-superoxide dismutase (SOD-1), catalase (CAT), and cytosolic glutathione peroxidase (GSH-Px) were examined in the erythrocytes before, immediately after and 2 weeks following PTCA or EC.

Results: The MDA concentrations were significantly higher and SOD-1, CAT, and GSH-Px activities were significantly lower in the PTCA group than in the EC group at baseline. Two weeks after treatment, the activities of the enzymes significantly increased in both groups, whereas the MDA concentrations decreased only in the PTCA patients.

Conclusions: The results confirm that an advanced state of atherosclerosis is related to greater levels of oxidative stress. The study indicates that both procedures may induce antioxidant defenses; however, PTCA exclusively induces a long-term reduction in lipid peroxidation.     

Kynurenic Acid Induces Impairment of Oligodendrocyte Viability: On the Role of Glutamatergic Mechanisms

Kynurenic acid (KYNA) is an end stage product of tryptophan metabolism with a variety of functions in the human body, both in the central nervous system (CNS) and in other organs. Although its activity in the human brain has been widely studied and effects on neural cells were emphasized, the effect of KYNA on oligodendroglial cells remains unknown. Present study aims at describing the activity of high concentration of KYNA in OLN-93 cells. The inhibition of OLN-93 oligodendrocytes viability by KYNA in a medium with reduced serum concentration has been demonstrated. Although decreased metabolic activity of KYNA treated OLN-93 cells was shown, the cells proliferation was not altered. KYNA treatment did not alter morphology as well as expression level of cell cycle and proliferation regulating proteins. Furthermore, glutamate receptor antagonists and agonists did not alter the inhibitory effect of KYNA on viability of OLN-93 oligodendrocytes. This study contributes to the elucidation of effects of KYNA on oligodendrocytes in vitro, yet further analyses are necessary to explain the mechanisms behind the damage and loss of myelin sheaths.     

Salicylic acid accumulation as a result of Cu,Zn, Cd and Pb interactions in common reed (<Emphasis Type="Italic">Phragmites australis</Emphasis>) growing in natural ecosystems

Common reed (Phragmites australis (Cav.) Trin. ex Steud.) plants were harvested from four natural water ecosystems of the Bogdanka river catchment (Poznań, Poland) four times throughout the 2014 vegetative season. Over the year, average metal contents followed different decreasing trends according to the analyzed tissue: Zn > Cu ≈ Pb > Cd (rhizomes) and Zn > Pb > Cu > Cd (leaves), and mean translocation ratios (leaves/rhizomes) were found as follows: 0.93, 0.70, 0.65, 0.40 for Zn, Pb, Cd and Cu, respectively. Metal content increased gradually during the growing season, and in the case of Cu, Cd and Pb exceeded the upper limit of average concentration detected in plants from natural ecosystems. However, the content of salicylic acid did not follow the increase of metal accumulation. In rhizomes, the highest production of the metabolite was observed in May and reached 324 ng g^?1 fresh weight (FW) (mean value). Afterwards, a significant drop to 50 ng g^?1 FW was observed. Simultaneously, the highest values of total salicylic acid in P. australis leaves were observed in July and accompanied the intensive development of the aboveground biomass of the plant (11.3 µg g^?1 FW–mean value). Subsequently, its content in leaves showed a significant decrease down to 2.1 µg g^?1 FW in November. Multivariate regression analysis revealed significant interactions between analyzed metals influencing the plant response to metal-derived stress. Cu and Zn showed antagonistic properties considering their uptake and the induction of salicylic acid biosynthesis, whereas non-essential metals (Pb and Cd) acted similarly and stimulated the formation of salicylic acid glucoside.     

Polyamines in yellow lupin (<Emphasis Type="Italic">Lupinus luteus</Emphasis> L.) tolerance to soil drought

Polyamines (PAs) are related to many physiological processes, including soil drought stress. Two yellow lupin ‘Morocco 4’ (drought tolerant) and ‘Taper’ (drought sensitive) were exposed to soil drought for 2 weeks. The half of the examined plants were additionally sprayed with a solution of polyamine biosynthesis inhibitor—dl-α-difluoromethylarginine (DFMA). Yellow lupin leaves showed a 19% increase and seeds a 54% decrease in the total PA contents. The seeds contained fourfold less PAs than the leaves under drought conditions. The highest amount of spermidine and lack of agmatine were found in the leaves, while in the seeds the highest content of spermine and the presence of agmatine was confirmed. The use of DFMA under drought conditions decreased the content of spermine in ‘Morocco 4’ and ‘Taper’ (41 and 19%, respectively) and spermidine in ‘Taper’ (by 13%), as well as reduced two out of three of the yield components. More tolerant ‘Morocco 4’, after DFMA treatment was characterized by a higher spermidine and spermine content and a smaller decrease in yield components compared to the less tolerant ‘Taper’. Simultaneously subjecting plants to soil drought and DFMA treatment caused in ‘Morocco 4’ a decline in the number of pods and seeds per plant and seeds dry weight per plant (64, 50 and 54%, respectively), while in ‘Taper’ a reduction of the number of pods per plant and seeds per pod (32 and 27%, respectively) was observed. These results confirm that PAs are involved in yellow lupin tolerance and may play a protective function under soil drought conditions.