The stacking interactions of bipyridine complexes: the influence of the metal ion type on the strength of interactions

The strength of the stacking interactions in the bipy complexes of nickel, palladium, and platinum, [M(CN)₂ bipy]₂ (M?=?Ni, Pd, Pt), was calculated using the ωB97xD/def2-TZVP method. The results show that for all considered geometries, interactions are the strongest for platinum, and weakest for nickel complexes, as a result of higher dispersion contributions of platinum over the palladium and nickel complexes. It was also shown that strength of interactions considerably rises with an increase of the stacking overlap area. As a consequence of the favorable electrostatic term, the strength of interactions also rises when metal atom and cyano ligands are involved in the overlap with bipy ligand. The strongest interaction was calculated in the platinum complex, for the geometry that has overlap of metal and cyano ligands with bipy ligand with an energy of -39.80 kcal mol^-1. The energies for similar geometries of palladium and nickel complexes are -34.60 and -32.45 kcal mol^-1. These energies, remarkably, exceed the strength of the stacking interactions between organic aromatic molecules. These results can be of importance in all systems with stacking interactions, from materials to biomolecules.     

Biometric approach in selecting plants for phytoaccumulation of uranium

This paper promotes the biometric classification system of plant cultivars, unique characteristics, in terms of the uranium (U) uptake, primarily in the function of the application for phytoremediation. It is known that the degree of adoption of U depends on the plant species and its morphological and physiological properties, but it is less known what impact have plants cultivars, sorts, and hybrids. Therefore, we investigated the U adoption in four cultivars of three plant species (corn, sunflower and soy bean). “Vegetation experiments were carried out in a plastic-house filled with soil (0.66 mgU) and with tailing (15.3 mgU kg^?1) from closed uranium mine Gabrovnica-Kalna southeast of Serbia”. Principal Component Analysis (PCA), Cluster Analysis (CA) and analysis of variance (ANOVA) were used for assessing the effect of different substrates cultivars, plant species and plant organs (root or shoot) on U uptake. Obtained results showed that a difference in U uptake by three investigated plant species depends not only of the type of substrate types and plant organs but also of their cultivars. Biometrics techniques provide a good opportunity for a better understanding the behavior of plants and obtaining much more useful information from the original data.     

Isolation and partial characterization of a mitochondrial deoxyribonucleic acid-protein complex from sea urchin embryos

Summary Lysis of mitochondria from sea urchin embryos with Triton X-100 led to a complete conversion of DNA-containing mitochondrial residues into protein-DNA complex with a density higher than 1.22 g/cm³ in sucrose solutions. This complex banded isopycnically in metrizamide gradients at a density of 1..26 g/cm³. Exposure to mixtures of Triton X-100 with Tween 80 resulted in progressively less delipitated and disorganized mitochondria over Tween/Triton weight ratios from 1 to 2, with the retention of the starting buoyant density in sucrose of approximately 1.16 g/cm³ at Tween/Triton ratios above 2.5. The DNA-internal protein complex sedimented with the bulk of the surviving mitochondrial structure under all conditions studied. No free DNA could be detected under any conditions of membrane removal.     

Aphids (Hemiptera,Aphididae) on ornamental plants in greenhouses in Bulgaria

Investigations on the species composition and host range of aphids on ornamental greenhouse plants in Bulgaria was conducted over a period of five years, from 2008 to 2012. Twenty greenhouses, growing ornamentals for landscaping, plant collections and other purposes were observed. They were located in the regions of Sofia, Plovdiv, Smolyan, Pavlikeni, Varna and Burgas. The total number of collected aphid samples was 279. Their composition included 33 aphid species and one subspecies from 13 genera and 5 subfamilies. Twenty-eight species were found to belong to subfamily Aphidinae. Almost 70 % of all recorded species were polyphagous. The most widespread aphid species was Myzus persicae, detected in 13 greenhouses all year round, followed by Aulacorthum solani (10 greenhouses) and Aphis gossypii (9 greenhouses). The widest host range was shown by Myzus persicae (43 hosts), Aulacorthum solani (32 hosts) and Aulacorthum circumflexum (23 hosts).The list of host plants includes 114 species from 95 genera and 58 families. The greatest variety of aphid species was detected on Hibiscus (9 species). Out of all aphid samples 12.9 % were collected on Hibiscus and 6.8 %, on Dendranthema. The greatest variety of aphid species was detected on Hibiscus (9 species).Periphyllus californiensis and Aphis (Aphis) fabae mordvilkoi are reported for the first time for Bulgaria. Furthermore, Aphis spiraecola has been found in new localities and has widened its host range in this country.     

Changes in cortisol binding to soluble receptor proteins in rat liver and thymus during development and ageing.

Changes in labeled cortisol binding to soluble cytoplasmic proteins of rat liver and thymus during development and ageing of animals have been observed.The relationship of age and cortisol binding to a fraction of soluble liver proteins precipitated at 50% saturation with ammonium sulfate displayed two maxima: The first one on the seventh day of postnatal life and the second one at 2.5 months of age. Binding of hormone to macromolecules of the same fraction prepared from older animals was less efficient. Almost the same picture has been obtained when total bound activity to macromolecular cytosol fraction was expressed per milligram of dry weight of liver.Binding of labeled cortisol to total cytosol macromolecules of liver and thymus was most efficient in 3-month-old animals and decreased after that, which is of interest in view of totally opposite effects of glucocorticoids upon various biosynthetic processes of these organs.     

Hepatoprotective effects of melatonin against pronecrotic cellular events in streptozotocin-induced diabetic rats

Oxidative stress-mediated damage to liver tissue underlies the pathological alterations in liver morphology and function that are observed in diabetes. We examined the effects of the antioxidant action of melatonin against necrosis-inducing DNA damage in hepatocytes of streptozotocin (STZ)-induced diabetic rats. Daily administration of melatonin (0.2 mg/kg) was initiated 3 days before diabetes induction and maintained for 4 weeks. Melatonin-treated diabetic rats exhibited improved markers of liver injury (P?<?0.05), alkaline phosphatase, and alanine and aspartate aminotransferases. Melatonin prevented the diabetes-related morphological deterioration of hepatocytes, DNA damage (P?<?0.05), and hepatocellular necrosis. The improvement was due to containment of the pronecrotic oxygen radical load, observed as inhibition (P?<?0.05) of the diabetes-induced rise in lipid peroxidation and hydrogen peroxide increase in the liver. This was accompanied by improved necrotic markers of cellular damage: a significant reduction in cleavage of the DNA repair enzyme poly(ADP-ribose) polymerase 1 (PARP-1) into necrotic 55- and 62-kDa fragments, and inhibition of nucleus-to-cytoplasm translocation and accumulation in the serum of the high-mobility group box 1 (HMGB1) protein. We conclude that melatonin is hepatoprotective in diabetes. It reduces extensive DNA damage and resulting necrotic processes. Melatonin application could thus present a viable therapeutic option in the management of diabetes-induced liver injury.     

Acute coronary syndrome frequency in western Herzegovina over the fifteen year period (1987-2001)

All patients who suffered from the acute coronary syndrome in western Herzegovina over the fifteen year period (1987-2001) are included in this retrospective epidemiological study. The population that was undertaken by the study is relative stabile and did not emigrate during the war period. The study compared the time before the war (1987-1991), during the war (1992-1996) and after the war (1997-2001). The data were acquired from the archives of the patients of the Mostar hospital and Clinical hospital Split during the war period. A total of 2022 acute coronary syndrome patients were found, 1305 men and 717 women. More patients were treated during the war compared to the time before the war for both male and female patients (p<0.0005). During the after-war period the number of treated patients was greater (p< 0.0005) compared to the war-time for both sexes. The comparison of the after-war period and the pre-war period reveals a statistically significant difference as the number of treated patients (male and female) is larger in the after-war period. The number of patient who are 65 years old and older than that is greater, and that is statistically significant (p= 0.0005.). We can conclude that the stress caused by the war and other factors have influenced a larger number of treated patients of acute coronary syndrome. Therefore, further epidemiological researches of acute coronary syndrome with the accent on prevention and treatment are needed.