Detection and quantification of group C rotaviruses in communal sewage

Group C rotaviruses have been recognized as a cause of acute gastroenteritis in humans, cattle, and swine, although the true epidemiologic and clinical importance of this virus in these hosts has not yet been fully established. A real-time PCR assay based on a broadly reactive primer pair was developed and used to quantitatively determine the viral load of group C rotaviruses in environmental samples. A total of 35 raw and 35 treated sewage samples collected at the same sampling time in four Hungarian sewage treatment plants during a survey in 2005 were tested for the presence of group C rotaviruses. The overall detection rates were 91% (32 of 35) for the influent and 57% (20 of 35) for the effluent samples. Molecular characterization of the amplified partial VP6 gene revealed the cocirculation of human and animal (i.e., bovine and porcine) strains that were easily distinguishable by melting curve analysis. Human strains yielded relatively high viral loads (mean, 1.2 x 10(7); median, 6.9 x 10(5) genome equivalents per liter influent sewage) and appeared to display seasonal activity over the study period, whereas animal strains appeared to circulate throughout the year at much lower average titers (bovine strains mean, 9.9 x 10(4); median, 3.0 x 10(4); porcine strains mean, 3.9 x 10(4); median, 3.1 x 10(4) genome equivalents per liter influent sewage). Our findings suggest that monitoring of communal sewage may provide a good surrogate for investigating the epidemiology and ecology of group C rotaviruses in humans and animals.     

The effects of the visual environment on responses to colour by domestic chicks

It is well known that development of vision is affected by experience, but there are few studies of environmental effects on colour vision. Natural scenes contain predominantly a restricted range of reflectance spectra, so such effects might be important, perhaps biasing visual mechanisms towards common colours. We investigated how the visual environment affects colour preferences of domestic chicks ( Gallus gallus), by training week-old birds to select small food containers distinguished from an achromatic alternative either by an orange or by a greenish-blue colour. Chicks that had been raised in control conditions, with long-wavelength-dominated reflectance spectra, responded more readily to orange than to blue. This was not due to avoidance of blue, as increasing saturation enhanced the chicks' preference for the same hue. The advantage of orange was, however, reduced or abolished for chicks raised in an environment dominated by blue objects. This indicates that responses to coloured food are affected by experience of non-food objects. If colours of ordinary objects in the environment do influence responses to specialised visual signals this might help explain why biological signals directed at birds are often coloured yellow, orange or red; long-wavelength-dominated spectra being more prevalent than short-wavelength-dominated spectra.     

Performance of Hungarian phylloxera strains on Vitis riparia rootstocks

Abstract: Vitis riparia and other rootstocks were used in excised root- and plantlet culture-bioassays to test the performance of Hungarian colonies of phylloxera. Phylloxera colonies from America and Germany were used as comparisons. The Hungarian colonies had a higher level of performance on V. riparia in contrast with the American and German colonies. Plantlet assays found the performance of a Hungarian strain on V. riparia equivalent to that on Vitis vinifera , AXR#1 and 41B root types. In contrast, the American colonies did not survive on V. riparia . Collections of Hungarian gallicole colonies from cultivated and escaped rootstock leaves were assayed using excised roots of the rootstock Teleki 5C. Results indicated that performance of phylloxera collected from feral rootstocks was higher than performance of colonies collected from cultivated rootstock leaves. Lastly, when the attached roots of field-grown V. riparia vines were damaged by girdling, phylloxera performance was much higher than on undamaged roots, suggesting cultural conditions can increase the risk of related vine damage. These laboratory and field results show that V. riparia is capable of supporting phylloxera on its roots. Escaped, feral vines may select for phylloxera with increased virulence on roots. This is of significance in regions such as Hungary where feral rootstock is common.     

Characterization of nociceptin binding sites by novel peptide analogs and radioprobes

A number of new synthetic nociceptin ligands were studied in receptor binding and functional tests in rat brain membranes and in cloned systems. Ligand binding experiments were performed with three different radioprobes developed in our lab. The nociceptin derivatives exhibited high affinity in competition experiments. Receptor‐mediated G‐protein activation was determined in [³⁵S]GTPgS binding assays. Among the new structures examined, Ac‐RYYRIK‐ol was found to be only a weak stimulator by itself, whereas this compound inhibited receptor‐mediated G‐protein activation. These data suggest that Ac‐RYYRIK‐ol is a high affinity peptide antagonist for the nociceptin receptor. Acknowledgements: Supported by the Hungarian Scientific Research Fund OTKA T‐035211, T‐033078, T‐030841, and the Ministry of Education, NKFP 1/027 Hungary.     

Enterotoxin production by Shigella flexneri type 2A, strain no. M42-43.

Enterotoxin produced by Shigella flexneri type 2a, strain M42-43, is similar to "Shig-like" cytotoxic enterotoxin and shares common features with that of other S. flexneri strains. On the basis of molecular filtration and neutralization experiments it is suggested that the same molecule carries these biological characters.     

Expression of endothelial nitric oxide synthase in the vascular wall during arteriogenesis

Nitric oxide (NO) has been demonstrated to play an important role in angiogenesis, and also to be involved in collateral vessel growth. The expression of endothelial NO synthase (eNOS) is moderated partly by blood flow-induced mechanical factors, i.e., shear stress. The purpose of this study was to evaluate how the expression of eNOS correlates with the development of collateral vessels in dog heart, induced by chronic occlusion of the left circumflex artery. Immunoconfocal microscopy using an antibody against eNOS was used to detect expression of eNOS in different stages of arteriogenesis. Collateral vessels were classified into normal, growing and mature vessels by using the cytoskeleton marker desmin. Expression of the growth factors bFGF and metallproteinase-2 (MMP-2) was also examined. The data show that in normal arteriolar vessels, expression of eNOS is very low, but in growing collateral vessel there is a 6.2-fold increase, which, however, returned to normal levels in mature collateral vessels. The expression of eNOS was localized only in endothelium, either in normal or growing vessels. bFGF was very weakly stained in normal vessels, but highly expressed in growing collateral vessels. MMP-2 was strongly stained in neointima, but very weak in endothelium. In addition, we also examined expression of iNOS because iNOS may be induced in vessel injury or in disease states, but it was not detected in either normal or growing collateral vessels. Our findings indicate that the expression pattern of eNOS is closely associated with the development of collateral vessels, suggesting that eNOS plays an important role in arteriogenesis. (Mol Cell Biochem 264: 193–200, 2004)     

Remodeling of the vascular tunica media is essential for development of collateral vessels in the canine heart

A method to study the export of citric acid cycle intermediates from rat liver mitochondria supplied with various individual substrates or combinations of substrates was designed to focus on the role of mitochondria in anaplerosis and cataplerosis. Under most conditions malate, citrate, and aspartate were exported in far higher amounts than isocitrate and alpha-ketoglutarate. In the presence of pyruvate alone or pyruvate in combination with most other substrates, citrate export equaled or was only slightly less than malate export. This contrasts with pancreatic islet mitochondria where citrate export is unaffected by many substrates. Malate and succinate potentiated pyruvate-induced citrate export and succinate caused massive malate export from liver mitochondria. Heart mitochondria, which possess very little or no pyruvate carboxylase, unlike liver and pancreatic islet mitochondria, did not produce malate from pyruvate. Heart mitochondria produced malate, but not citrate, from succinate. The results indicate that liver mitochondria export a larger number of metabolites from a wider range of substrates than do islet or heart mitochondria. This may reflect the multiple roles of the liver in body metabolism versus the specialized roles of the islet cell and heart.     

Expression of endothelial nitric oxide synthase in the vascular wall during arteriogenesis

Nitric oxide (NO) has been demonstrated to play an important role in angiogenesis, and also to be involved in collateral vessel growth. The expression of endothelial NO synthase (eNOS) is moderated partly by blood flow-induced mechanical factors, i.e., shear stress. The purpose of this study was to evaluate how the expression of eNOS correlates with the development of collateral vessels in dog heart, induced by chronic occlusion of the left circumflex artery. Immunoconfocal microscopy using an antibody against eNOS was used to detect expression of eNOS in different stages of arteriogenesis. Collateral vessels were classified into normal, growing and mature vessels by using the cytoskeleton marker desmin. Expression of the growth factors bFGF and metallproteinase-2 (MMP-2) was also examined. The data show that in normal arteriolar vessels, expression of eNOS is very low, but in growing collateral vessel there is a 6.2-fold increase, which, however, returned to normal levels in mature collateral vessels. The expression of eNOS was localized only in endothelium, either in normal or growing vessels. bFGF was very weakly stained in normal vessels, but highly expressed in growing collateral vessels. MMP-2 was strongly stained in neointima, but very weak in endothelium. In addition, we also examined expression of iNOS because iNOS may be induced in vessel injury or in disease states, but it was not detected in either normal or growing collateral vessels. Our findings indicate that the expression pattern of eNOS is closely associated with the development of collateral vessels, suggesting that eNOS plays an important role in arteriogenesis.     

Role of vascular adrenergic mechanisms in the haemodynamic and PGI2 stimulating effects of angiotensin in diabetic dogs

In aware of the well-known altered vascular responsiveness in the diabetic vasculature, this study aimed to compare the haemodynamic and PGI₂ releasing effects of angiotensin in metabolically healthy (12) and alloxan-(560 umol/kg) diabetic (12) dogs as well as to analyze the role of vascular adrenoceptors in this. In vivo the effect of intracoronarially administered angiotensin (63-125-250-500-1000 pmol/kg/min) on coronary blood flow, mean arterial blood pressure, myocardial contractile force and heart rate was investigated without and with pretreatment of 2 umol/kg phentolamine. In vitro PGI₂ release by isolated coronary rings was induced by 50 nmol/1 angiotensin before and after pretreatment with 5 umol/1 phentolamine and measured by radioimmunoassay. Angiotensin enhances dose-dependently both the mean arterial blood pressure and coronary blood flow, while it provokes a considerable (p < 0.05) increase of PGI₂ formation by isolated coronary arterial rings. These alterations could be prevented by phentolamine administration both in vivo and in vitro, while this drug did not affect the angiotensin-induced enhancement of diabetic coronary blood flow. On the other hand the increase of blood pressure by angiotensin was found to be more (p < 0.05) expressed in diabetes and it could be further potentiated by phentolamine. PGI₂ synthesis by isolated diabetic coronary rings could not be modified either by angiotensin alone or in combination with phentolamine. On the basis of above data, the lack of stimulated vascular PGI₂ formation mediated by alpha-adrenergic mechanisms is supposed to causatively contribute to the diminished sensitivity of diabetic coronary arteries to vasodilation.     

Dimethylsulfoniopropionate Biosynthesis in Spartina alterniflora : Evidence That S-Methylmethionine and Dimethylsulfoniopropylamine Are Intermediates

The osmoprotectant 3-dimethylsulfoniopropionate (DMSP) occurs in Gramineae and Compositae, but its synthesis has been studied only in the latter. The DMSP synthesis pathway was therefore investigated in the salt marsh grass Spartina alterniflora Loisel. Leaf tissue metabolized supplied [³⁵S]methionine (Met) to S-methyl-l-Met (SMM), 3-dimethylsulfoniopropylamine (DMSP-amine), and DMSP. The ³⁵S-labeling kinetics of SMM and DMSP-amine indicated that they were intermediates and, consistent with this, the dimethylsulfonium moiety of SMM was shown by stable isotope labeling to be incorporated as a unit into DMSP. The identity of DMSP-amine, a novel natural product, was confirmed by both chemical and mass-spectral methods. S. alterniflora readily converted supplied [³⁵S]SMM to DMSP-amine and DMSP, and also readily converted supplied [³⁵S]DMSP-amine to DMSP; grasses that lack DMSP did neither. A small amount of label was detected in 3-dimethylsulfoniopropionaldehyde (DMSP-ald) when [³⁵S]SMM or [³⁵S]DMSP-amine was given. These results are consistent with the operation of the pathway Met → SMM → DMSP-amine → DMSP-ald → DMSP, which differs from that found in Compositae by the presence of a free DMSP-amine intermediate. This dissimilarity suggests that DMSP synthesis evolved independently in Gramineae and Compositae.