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161.
Cormorants (median numbers of 54.5 ind.) excreted ca. 102.7 kg yr−1 of nitrogen and ca. 80.5 kg yr−1 of phosphorus in the area of the Dobczyce Reservoir (ca. 980 ha). Concentrations of N-tot and P-tot were 3 times higher in
soil from the roosting area of the cormorants than outside this area. Nutrient concentrations in the littoral sediment of
the reservoir were also higher in the area frequented by these birds. Differences in concentrations of pH, NO3−, NO2−, NH4+, PO4−, and P-tot in water between the area associated with the cormorants and the reference site were not found. Differences in
the planktonic algal communities from around the roost and the reference site were not found, with the exception of the chlorophytes
which were more abundant in the area occupied by the cormorants. Water movement and mixing in the reservoir can influence
the effect of the nutrient load on the water chemistry and planktonic algae. 相似文献
162.
Leber hereditary optic neuropathy (LHON), acute or subacute vision loss due to retinal ganglion cell death which in the long run leads to optic nerve atrophy is one of the most widely studied maternally inherited diseases caused by mutations in mitochondrial DNA. Although three common mutations, 11778G>A, 14484T>C or 3460G>A are responsible for over 90% of cases and affect genes encoding complex I subunits of the respiratory chain, their influence on bioenergetic properties of the cell is marginal and cannot fully explain the pathology of the disease. The following chain of events was proposed, based on biochemical and anatomical properties of retinal ganglion cells whose axons form the optic nerve: mitochondrial DNA mutations increase reactive oxygen species production in these sensitive cells, leading to caspase-independent apoptosis. As LHON is characterized by low penetrance and sex bias (men are affected about 5 times more frequently than women) the participation of the other factors—genetic and environmental—beside mtDNA mutations was studied. Mitochondrial haplogroups and smoking are some of the factors involved in the complex etiology of this disease. 相似文献
163.
Magdalena Lebiedzinska Agnieszka Karkucinska-Wieckowska Carlotta Giorgi Elzbieta Karczmarewicz Ewa Pronicka Paolo Pinton Jerzy Duszynski Maciej Pronicki Mariusz R. Wieckowski 《BBA》2010,1797(6-7):952-960
p66Shc, the growth factor adaptor protein, can have a substantial impact on mitochondrial metabolism through regulation of cellular response to oxidative stress. We investigated relationships between the extent of p66Shc phosphorylation at Ser36, mitochondrial dysfunctions and an antioxidant defense reactions in fibroblasts derived from five patients with various mitochondrial disorders (two with mitochondrial DNA mutations and three with methylglutaconic aciduria and genetic defects localized, most probably, in nuclear genes). We found that in all these fibroblasts, the extent of p66Shc phosphorylation at Ser36 was significantly increased. This correlated with a substantially decreased level of mitochondrial superoxide dismutase (SOD2) in these cells. This suggest that SOD2 is under control of the Ser36 phosphorylation status of p66Shc protein. As a consequence, an intracellular oxidative stress and accumulation of damages caused by oxygen free radicals are observed in the cells. 相似文献
164.
165.
Epidemiological studies were carried out on 135 isolates of Staphylococcus aureus strains originating from medical staff, patients, and hospital environment. Restriction fragment length polymorphism (RFLP) analysis revealed genetic diversity of S. aureus isolates. Some clones were transmitted among nurses, doctors and patients. Our studies also demonstrate contamination of the hospital environment with S. aureus strains and there is a possibility that the patients acquire staphylococci from the environment. Moreover, we found that many medical staff workers were colonized with S. aureus and the transmission of these strains to patients is possible. 相似文献
166.
Background
FYVE domains have emerged as membrane-targeting domains highly specific for phosphatidylinositol 3-phosphate (PtdIns(3)P). They are predominantly found in proteins involved in various trafficking pathways. Although FYVE domains may function as individual modules, dimers or in partnership with other proteins, structurally, all FYVE domains share a fold comprising two small characteristic double-stranded β-sheets, and a C-terminal α-helix, which houses eight conserved Zn2+ ion-binding cysteines. To date, the structural, biochemical, and biophysical mechanisms for subcellular targeting of FYVE domains for proteins from various model organisms have been worked out but plant FYVE domains remain noticeably under-investigated. 相似文献167.
168.
Zalejska-Fiolka J Kasperczyk A Kasperczyk S Błaszczyk U Birkner E 《Biological trace element research》2007,120(1-3):195-204
Effect of garlic supplementation on blood antioxidant status, lipid peroxidation, and coronary plaque formation process was
investigated in oxidized oil-fed rabbits. Eighteen adult male mixed European rabbits were given a balanced diet (21 g% protein,
34 g% fat, 45 g% carbohydrate), which contained isocaloristic addition of nonoxidized or oxidized rapeseed oil in the presence
and absence of garlic. The experiment lasted 24 weeks. At the beginning and every 6 weeks, rabbits were weighed, and blood
was taken. To evaluate the antioxidant status of the rabbits, erythrocytes malondialdehyde (MDA) concentration, total superoxide
dismutase (t-SOD), and glutathione peroxidase (GPX) activations were determined. After the experiment was completed, aortas
were dissected for histological examinations. Changes in the contents of the above parameters and histological examinations
showed that oxidized rapeseed, oil administered to rabbits, caused the development of atherosclerotic changes and disturbed
antioxidant status. The addition of garlic in such diets inhibited atherosclerotic changes in the aorta wall, and it is related
to the homeostatic activity of antioxidative enzymes and lipid peroxidation. 相似文献
169.
Cudnoch-Jedrzejewska A Dobruch J Puchalska L Szczepańska-Sadowska E 《Regulatory peptides》2007,142(3):86-94
Experimental objectives. Because myocardial infarct is associated with overactivation of brain angiotensin II (ANG II) and vasopressin (AVP) V1a receptors we decided to determine whether AT1 and V1a receptors-mediated effects of ANG II and AVP interact in central cardiovascular control during the post-infarct state. Four groups of infarcted and four groups of sham-operated conscious rats entered the study. Results. In the infarcted rats cerebroventricular infusion of AT1 (AT1ANT, losartan) and V1a antagonist {V1aANT,d(CH(2))(5)[Tyr(Me)(2)Ala-NH(2)(9)]VP} and combined infusion of both these compounds performed 4 weeks after induction of the infarct significantly and comparably reduced mean arterial blood pressure (MABP) in comparison to control experiments (artificial cerebrospinal fluid infusion). In the sham rats MABP was not affected by any of the infusions. In control experiments MABP and HR responses to an alarming air jet stress were significantly higher in the infarcted than in the sham rats. Both responses were normalized with the same effectiveness by administration of AT1ANT, V1aANT and AT1ANT+V1aANT. In the sham rats administration of these compounds did not affect MABP and HR responses to stress. Conclusion: The results provide evidence for interaction of AT1 and V1a receptors-mediated effects of ANG II and AVP in the central cardiovascular control during the post-infarct state. 相似文献
170.
In Arabidopsis the in vitro culture of immature zygotic embryos (IZEs) at a late stage of development, on the solid medium containing synthetic
auxin, leads to formation of somatic embryos via direct somatic embryogenesis (DSE). The presented results provide evidence
that in IZE cells competent for DSE are located in the protodermis and subprotodermis of the adaxial side of cotyledons and
somatic embryos displayed a single- or multicellular origin. Transgenic Arabidopsis lines expressing the GUS reporter gene, driven by the DR5 and LEC2 promoters, were used to analyse the distribution of auxin to mark embryogenic cells in cultured explants and develop somatic
embryos. The analysis showed that at the start of the culture auxin was accumulated in all explant tissues, but from the fourth
day onwards its location shifted to the protodermis and subprotodermis of the explant cotyledons. In globular somatic embryos
auxin was detected in all cells, with a higher concentration in the protodermis, and in the heart stage its activity was mainly
displayed in the shoot, root pole and cotyledon primordia. The embryogenic nature of dividing protodermal and subprotodermal
cells accumulating auxin was confirmed by high expression of promoter activity of LEC2 in these cells. Analysis of symplasmic tracer (CFDA) distribution indicated symplasmic isolation between tissues engaged
in DSE and other parts of an explant. Symplasmic isolation of somatic embryos from the explant was also detected. 相似文献