Early events responsible for aluminum toxicity symptoms in suspension-cultured tobacco cells

We investigated the aluminum (Al)-induced alterations in zeta potential, plasma membrane (PM) potential and intracellular calcium levels to elucidate their interaction with callose production induced by Al toxicity. A noninvasive confocal laser microscopy has been used to analyse the live tobacco (Nicotiana tabacum) cell events by means of fluorescent probes Fluo-3 acetoxymethyl ester (intracellular calcium) and DiBAC4 (PM potential) as well as to monitor callose accumulation. Log-phase cells showed no detectable changes in the PM potential during the first 30 min of Al treatment, but sustained large depolarization from 60 min onwards. Measurement of zeta potential confirmed the depolarization effect of Al, but the kinetics were different. The Al-treated cells showed a moderate increase in intracellular Ca2+ levels and callose production in 1 h, which coincided with the time course of PM depolarization. Compared with the Al treatment, cyclopiazonic acid, an inhibitor of endoplasmic reticulum Ca(2+)-ATPase, facilitated a higher increase in intracellular Ca2+ levels, but resulted in accumulation of only moderate levels of callose. Calcium channel modulators and Al induced similar levels of callose in the initial 1 h of treatment. Callose production induced by Al toxicity is dependent on both depolarization of the PM and an increase in intracellular Ca2+ levels.     

Cerebrovascular insult hospital cases in the Clinical Hospital Mostar (Bosnia and Herzegovina) from 1999 to 2003--an example of an institutional register

The analysis of a cerebro-vascular insult hospitalized cases in the Clinical Hospital Mostar as a retrospective epidemiological study was done in the Clinical Hospital Mostar for the period from 1999 to 2003. The major source of data was medical documentation of this hospital (an institutional register), the only hospital for the treatments of 457,491 inhabitants who gravitate by a health insurance for the treatment in this hospital. The study included a total of 1,555 cerebro-vascular insult cases treated in the Clinical Hospital Mostar Among them 727 (46.8%) were male patients, while 828 (53.2%) cases were female. The majority of the cases were above 50 years of life. Majority of treated female patients were older than 61 (45.6% of all cases), as well as among male patients (31.3%). The least number of cases was under 41 years in both groups (1.2%). Prevalence of risk factors was 2,035 cases (74%). During the same period risk factors research for entire Federation of Bosnia and Herzegovina (FBiH) was performed on the sample of 2,750 national insurance holders, out of which 852 gravitate for treatment in CB Mostar. Out of them 1.7% was found to suffer of cerebro vascular insult.     

Effects of bovine spermatozoa preparation on embryonic development in vitro

The aim of our research was to examine the ability of density gradient preparation BoviPure^? and swim up method on bull sperm separation and in vitro embryo production (IVP) systems. Frozen/thawed semen from six Simmental bulls was pooled and treated using both methods. The sperm motility, concentration, membrane activity, membrane integrity and acrosomal status were evaluated and compared before and after sperm processing using BoviPure^? and swim up methods. We also evaluated and compared cleavage rates, embryo yield and quality between the methods. There were significant differences (P < 0.05) between the sperm characteristics before and after BoviPure^?, but not after swim up method. However, there were significant differences for sperm results among those two mentioned methods. A total of 641 oocytes were matured and fertilized in vitro and cultured in SOFaaBSA. The percentage of cleavage (Day 2) and the percentage of hatched embryos (Day 9) were similar for both methods. However, embryo production rate (Day 7) was significantly higher using BoviPure^? method (P < 0.05). Also, total cell number and embryo differential staining (inner cell mass and trophectoderm cells) of Day 7 morulas and blastocysts showed that BoviPure^? treated sperm displayed higher quality embryos compared to swim up method (P < 0.05). Our results indicate that BoviPure^? method has an enhanced capacity in sperm selection for in vitro embryo production when compared with swim up method. So, we concluded that BoviPure^? could be considered as a better alternative to swim up method for separating bull spermatozoa from frozen/thawed semen for IVP of bovine embryos.     

Detection of ovarian cancer by determination of CA 125 in different patohistologycal types of tumor according to age

During the eighteen-year period in "Sestre milosrdnice" University Hospital Center, Zagreb, 271 women with ovarian tumor was studied. 229 women with ovarian cancer and 42 with borderline tumor. The pathohistological types of tumors were different. The age of the patients ranged from 20-83 years. In all patients the value of biochemical marker CA125 was determined. The aim of this study was to determine the usefulness of CA125 measurement in different age groups and in different patohistologycal forms of tumor. CA125 has proven to be positive in 89.1% of women with ovarian cancer and in 62% with neoplasm of low malignant potential. The higher values of CA125 were detected in younger women with low malignant tumor potential. Serous and metastatic tumor types were also associated with higher values of CA125.     

Using alfalfa (Medicago sativa) to ameliorate salt-affected soils in Yingda irrigation district in Northwest China

Secondary salinization of soil is a major limiting factor of agricultural sustainability and recovery of functional environments in irrigated agriculture in arid and semi-arid regions. The ameliorating effect of planting alfalfa (Medicago sativa) on salt-affected soils was assessed in field experiments in the irrigated region of Qingwangchuan basin for 5 years. The results showed that salt content in the soil profile gradually decreased with duration of alfalfa cultivation. Soil EC in the layer of 0-20 cm decreased significantly. The concentrations of soluble anions were found to be in the order of Cl^- > SO₄^2- > HCO₃^- in the soil profile of the study area. After alfalfa planting, Cl^- concentration in the soil profile notably decreased. In contrast, HCO₃^- concentration was significantly higher in the topsoil planted to alfalfa than in unplanted soil, especially after the first and the second year of cultivation, but markedly decreased after 3 years of alfalfa growth. With the extension of cultivation ages, total N content in different soil layers gradually increased through N2 fixation. Organic matter content in the soil profile was not enhanced significantly until the later stages of alfalfa cultivation. Available P accumulated in the topsoil in dependence on the length of cultivation. Soil pH was significantly higher in the planted than unplanted treatment, but was gradually decreased with increased duration of cultivation, especially in topsoil. Significant differences in ash content of alfalfa shoot were found between the different cultivation ages. Alfalfa shoot Na concentration showed slightly decrease, whereas shoot Cl^- concentration decreased with the duration of cultivation. The ameliorating effect of alfalfa cultivation on salt-affected soil showed a spatial and temporal variability due to the interactions between soil and plants. This positive effect resulted in either the salt leaching from the root zone to below 80-cm depth by irrigation water or the removal of less salts through harvest of alfalfa shoots.     

Epigenetic drivers and genetic passengers on the road to cancer

Cancer is traditionally viewed as a primarily genetic disorder, however it is now becoming accepted that cancer is also a consequence of abnormal epigenetic events. Genetic changes and aneuploidy are associated with alterations in DNA sequence, and they are a hallmark of the malignant process. Epigenetic alterations are universally present in human cancer and result in heritable changes in gene expression and chromatin structure over many cell generations without changes in DNA sequence, leading to functional consequences equivalent to those induced by genetic alterations. Importantly, intriguing evidence emerged suggesting that epigenetic changes may precede and provoke genetic changes. In this scenario, epigenetic events are primary events while genetic changes (such as mutations) may simply be a consequence of disrupted epigenetic states. This fact may explain why many genetic screens proved to be limited with regard to cancer causality and pathogenesis. Aberrant epigenetic events affect multiple genes and cellular pathways in a non-random fashion and this can predispose to induction and accumulation of genetic changes in the course of tumour initiation and progression. These considerations are critical for a better understanding of tumourigenesis and molecular events underlying the acquisition of drug resistance, as well as development of novel strategies for cancer therapy and prevention.     

Importance of the cyanobacterial Gun4 protein for chlorophyll metabolism and assembly of photosynthetic complexes

Gun4 is a porphyrin-binding protein that activates magnesium chelatase, a multimeric enzyme catalyzing the first committed step in chlorophyll biosynthesis. In plants, GUN4 has been implicated in plastid-to-nucleus retrograde signaling processes that coordinate both photosystem II and photosystem I nuclear gene expression with chloroplast function. In this work we present the functional analysis of Gun4 from the cyanobacterium Synechocystis sp. PCC 6803. Affinity co-purification of the FLAG-tagged Gun4 with the ChlH subunit of the magnesium chelatase confirmed the association of Gun4 with the enzyme in cyanobacteria. Inactivation of the gun4 gene abolished photoautotrophic growth of the resulting gun4 mutant strain that exhibited a decreased activity of magnesium chelatase. Consequently, the cellular content of chlorophyll-binding proteins was highly inadequate, especially that of proteins of photosystem II. Immunoblot analyses, blue native polyacrylamide gel electrophoresis, and radiolabeling of the membrane protein complexes suggested that the availability of the photosystem II antenna protein CP47 is a limiting factor for the photosystem II assembly in the gun4 mutant.     

Interactive effects of N and P on growth but not on resource allocation of Canna indica in wetland microcosms

The interactive effects of three levels of N (mM) (low 0.36, medium 2.1 and high 6.4) and two levels of P (mM) (low 0.10 and high 0.48) on growth and resource allocation of Canna indica Linn. were studied in wetland microcosms. After 91 days of plant growth, there was a significant interactive effect of N and P on plant growth, but not on resource allocation (except for allocation of N to leaves and allocation of P to the stems). The plant growth positively responded to the relatively higher nutrient availability (taller plants with more stems, leaves and flowers), but the growth performance was not significantly different between the medium N-low P and high N-low P treatments. At high P, the total biomass in the high N was about 51% higher than that in the medium N and about 348% higher than that in the low N. The growth performance was related to the physiological responses. The photochemical efficiency (F_v/F_m) increased from 0.843 to 0.855 with an increase in N additions. The photosynthetic rate increased from 13 to 16 μmol m⁻² s⁻¹ in the low P levels and from 14 to 20 μmol m⁻² s⁻¹ in the high P levels with an increase in N applications, but significant difference was only between the low and medium N levels, regardless of the P levels. The tissue concentrations of N increased with an increase in N applications and decreased with an increase in P additions, whereas reverse was true for tissue concentrations of P. The highest concentrations of N and P in leaves were 30.8 g N kg⁻¹ in the high N-low P treatment and 4.9 g P kg⁻¹ in the low N-high P treatment. The percent biomass allocation to aboveground tissues in the high N was nearly twice that in the low N treatments. The N allocation to aboveground tissues was slightly larger in high N than in low N treatments, whereas the P allocation to aboveground tissues increased with an increase in the N addition. Although some patterns of biomass allocation were similar to those of nutrient allocation, they did not totally reflect the nutrient allocation. These results imply that in order to enhance the treatment performance, appropriately high nutrient availability of N and P are required to stimulate the growth of C. indica in constructed wetlands.