Effects of bud removal in Scots pine (Pinus silvestris) seedlings

One- and two-“year”-old seedlings of Pinus silvestris L., from which the buds had been removed, were studied for five weeks during the second and third growth period, respectively. Intact seedlings were used as controls. The seedlings were cultivated under controlled conditions in a climate chamber. The growth of the seedlings was determined and the one-“year”-old needles assayed for changes in net photosynthesis and ribulose bisphosphate carboxylase activity and in the levels of protein, Kjeldahl nitrogen, chlorophyll and starch. In the control the carboxylase activity and the content of protein, Kjeldahl nitrogen and starch in the needles increased in the beginning of the “summer” and decreased during the shoot growth period. The starch content was higher after bud removal (decapitation), since the carbohydrate could not be utilized for the growth of the new shoot. Decapitation did not affect the growth rate of the roots. The content of Kjeldahl nitrogen and total and soluble protein in the needles was higher in the decapitated seedlings during the period of shoot elongation in the control. Total nitrogen, but not protein, reached high levels, indicating accumulation of non-protein compounds. The general course of the chlorophyll pattern was not affected. Higher ribulose bisphosphate carboxylase activity than in the control was observed in the later part of the experimental periods. The higher levels of protein and nitrogen as well as of carboxylase activity after decapitation support the interpretation that soluble protein, including the carboxylase, and possibly other nitrogen compounds in the older needles are used for growth of the shoot. The loss of protein and nitrogen and of carboxylase activity in the control did not seem to be due to mineral deficiency in the substrate. Despite higher levels of carboxylase activity and similar chlorophyll concentrations, light-saturated net photosynthesis was lower after decapitation. The ratio between photosynthesis and photorespiration was not affected.     

Induction of cytokinesis is independent of precisely regulated microtubule dynamics

Astral microtubules (MTs) emanating from the mitotic apparatus (MA) during anaphase are required for stimulation of cytokinesis in eggs. We have used green fluorescent protein-labeled EB1 to observe MT dynamics during mitosis and cytokinesis in normal sea urchin eggs. Analysis of astral MT growth rates during anaphase shows that MTs contact the polar cortex earlier than the equatorial cortex after anaphase onset but that a normal cleavage furrow is not induced until contact with MTs has been achieved throughout the cortex. To assess the role of MT dynamics in initiation of cytokinesis, we used a collection of small molecule drugs to affect dynamics. Hexylene glycol resulted in rapid astral elongation due to decreased MT catastrophe and precocious furrowing. Taxol suppressed MT dynamics but did not inhibit furrow induction when the MA was manipulated toward the cortex. Urethane resulted in short, highly dynamic astral MTs with increased catastrophe that also stimulated furrowing upon being brought into proximity to the cortex. Our findings indicate that astral MT contact with the cortex is necessary for furrow initiation but that the dynamic state of astral MTs does not affect their competency to stimulate furrowing.     

Evidence of cardiovascular protection by moderate alcohol: role of nitric oxide

Epidemiological evidence indicates that moderate alcohol consumption reduces the incidence of heart disease. Endothelial nitric oxide synthase (eNOS) is a key regulator of vascular homeostasis and myocardial functions through the controlled production of nitric oxide (*NO). These studies were conducted to determine if the apparent alcohol-associated cardioprotection is mediated, in part, through modulation of the eNOS protein and activity in the cardiovascular system. Rats were fed alcohol and eNOS protein and *NO production were evaluated at the end of 8 weeks. Myocardial and vascular function was assessed ex vivo in a subset of animals. Moderate alcohol improved postischemic myocardial systolic and diastolic function and attenuated the postischemic reduction in coronary vascular resistance. Moderate alcohol also enhanced maximum vascular relaxation by 26 +/- 0.2% and increased plasma *NO production concomitant with a greater than 2.5-fold increase in eNOS protein. Higher levels of alcohol impaired maximum vascular relaxation by 22 +/- 0.1%. These results suggest that moderate alcohol improves postischemic myocardial functions and increases *NO production by vascular endothelium. An increase in *NO may explain, at least in part, the cardioprotective benefits of moderate alcohol consumption.     

Mutational analysis of the IFNAR1 binding site on IFNalpha2 reveals the architecture of a weak ligand-receptor binding-site

Type I interferons activate cellular responses by forming a ternary complex with two receptor components, IFNAR1 and IFNAR2. While the binding of the IFNAR2 receptor to interferon is of high affinity and well characterized, the binding to IFNAR1 is weak, transient, and poorly understood. Here, we mapped the complete binding region of IFNAR1 on IFNalpha2 by creating a panel of 21 single alanine mutant proteins, and determined their binding affinities. The IFNAR1 binding site on IFNalpha2 maps to the center of the B and C helices, opposite to the binding site for IFNAR2. No hot spots for binding were found in the interface, with individual mutations having an up to fivefold effect on binding. Of the nine residues that affected binding, three adjacent conserved residues, located on the B helix, conferred an increase in the binding affinity to IFNAR1, as well as an increase in the biological activity of the interferon mutant. This suggests that binding of alpha interferons to the IFNAR1 receptor is sub-optimal. A correlation between binding affinity and biological activity was found, albeit not across the whole range of affinities. In WISH cells, but not DAUDI cells, the anti-proliferative activity was markedly affected by fluctuations in the IFNalpha2 affinity towards the IFNAR1 receptor. On the other hand, the antiviral activity of interferons on WISH cells seems to change in accordance to the binding affinity towards IFNAR1 only as long as the binding affinity is not beyond twofold of the wild-type. In accordance, the biological roles of the two interferon-receptor subunits are discussed.     

Phytostabilization of polymetallic contaminated soil using Medicago sativa L. in combination with powdered marble: Sustainable rehabilitation

This study uses an ecotoxicology approach to evaluate the effectiveness of combining powdered marble as an amendment, with phytostabilization by Medicago sativa L. on the neutralization of acidic mine tailings, and the stabilization of heavy metals. The mine tailings were collected from an abandoned polymetallic mine in Southern Morocco, and mixed with powdered marble as the following proportions, 25%, 50%, and 75%. Laboratory immobilization/stabilization tests showed that the application of powdered marble in the treatments led to a significant increase in pH, and significant reductions of Cu, Zn (99%), Pb (98%), and Fe (45%). Greenhouse experiments showed that plant growth in all treatments was significantly (p ≤ 0.05) less than growth in agricultural soil. Plant growth significantly (p ≤ 0.05) decreased as the proportion of powdered marble increased. The concentration of metals in plant roots were significantly (p ≤ 0.05) higher than those of shoots. Combining immobilization by powdered marble with phytostabilization by M. sativa L. could represent a viable method of rehabilitating acidic polymetallic mine tailings.     

Sclerosing angiomatoid nodular transformation of the spleen (SANT) in a patient with clear cell carcinoma of the uterus: a case report

Background

Sclerosing angiomatoid nodular transformation of the spleen is a very rare benign vascular lesion recently described. Usually, sclerosing angiomatoid nodular transformation of the spleen is an incidental finding; the association with malignant tumors is extremely rare. To the best of our knowledge, we report the first case of sclerosing angiomatoid nodular transformation of the spleen associated with uterine clear cell carcinoma.

Case presentation

A 49-year-old Arabic woman presented to our institute with abdominal pain and distention. An abdominal computed tomographic scan was obtained, which showed a 14-cm uterine malignant tumor and a 4-cm isolated splenic nodule suggesting a metastatic lesion. The tumor was limited to the uterus but did not extend beyond. The patient underwent surgical treatment, and the histopathological examination of the resected uterine and splenic specimens disclosed invasive uterine clear cell carcinoma and sclerosing angiomatoid nodular transformation of the spleen, respectively. The patient had no signs of the disease 17 months after surgical treatment.

Conclusions

Sclerosing angiomatoid nodular transformation of the spleen is a very rare benign disease with a misleading presentation when associated with a malignant tumor. Pathological assessment of the resected spleen is the only way to achieve the correct diagnosis.

     

Acute toxicity of nitrite in fat snook (Centropomus parallelus)

Oxidative stress and hypoxia responses in Centropomus parallelus exposed to three different concentrations of nitrite (0, 0.5, and 10 mg L^?1) were evaluated. To determinate toxicity, we used enzymatic analyses and quantifications of oxygen consumption and opercular beats under conditions of normoxia and hypoxia. There was no significant difference in GST, CAT, or GPx enzymes in the liver or in GPx in the gills. Levels of GST were altered at a concentration of 10 mg L^?1 in experiment I. Experiment II displayed alterations for GST and CAT in the liver at the same concentration, indicating that exposure to nitrite does not generate differentiated activation in the body’s defense system by the production of oxidative stress enzymes. When nitrite was associated with hypoxia, there was a significant increase in both enzymatic activity and opercular beating under hypoxia in the group exposed to 10 mg L^?1 nitrite compared to the control.     

Estrogen rescues heart failure through estrogen receptor Beta activation

Background

Recently, we showed that exogenous treatment with estrogen (E2) rescues pre-existing advanced heart failure (HF) in mice. Since most of the biological actions of E2 are mediated through the classical estrogen receptors alpha (ERα) and/or beta (ERβ), and both these receptors are present in the heart, we examined the role of ERα and ERβ in the rescue action of E2 against HF.

Methods

Severe HF was induced in male mice by transverse aortic constriction-induced pressure overload. Once the ejection fraction (EF) reached ~?35%, mice were treated with selective agonists for ERα (PPT, 850 μg/kg/day), ERβ (DPN, 850 μg/kg/day), or E2 (30 μg/kg/day) together with an ERβ-antagonist (PHTPP, 850 μg/kg/day) for 10 days.

Results

EF of HF mice was significantly improved to 45.3?±?2.1% with diarylpropionitrile (DPN) treatment, but not with PPT (31.1?±?2.3%). E2 failed to rescue HF in the presence of PHTPP, as there was no significant improvement in the EF at the end of the 10-day treatment (32.5?±?5.2%). The improvement of heart function in HF mice treated with ERβ agonist DPN was also associated with reduced cardiac fibrosis and increased cardiac angiogenesis, while the ERα agonist PPT had no significant effect on either cardiac fibrosis or angiogenesis. Furthermore, DPN improved hemodynamic parameters in HF mice, whereas PPT had no significant effect.

Conclusions

E2 treatment rescues pre-existing severe HF mainly through ERβ. Rescue of HF by ERβ activation is also associated with stimulation of cardiac angiogenesis, suppression of fibrosis, and restoration of hemodynamic parameters.