Control of nucleotide and erythroascorbic acid pools by cyclic AMP in Neurospora crassa.

UDPglucuronic acid and erythroascorbic acid were identified in extracts of the fungus Neurospora crassa. The concentrations of these two compounds are estimated, in growing wild type N. crassa, to be about 0.10 and 0.28 mumol/ml of cell water, respectively. The pools of these two compounds are regulated by cyclic AMP in Neurospora, both being elevated in the cr-1, adenylate cyclase deficient mutant and both being lowered by exogenous cyclic AMP. The pools of these two compounds are also elevated on nitrogen deprivation. The pools of a large number of other nucleotides are not influenced by cyclic AMP. Possible relationships between the metabolism of UDPglucuronic acid and erythroascorbic acid are discussed. It was found that exogenous cyclic AMP was much more effective in influencing cultures grown at 30-37 degrees C than those grown at 25 degrees C. We suggest that higher temperatures may render Neurospora more permeable to a variety of different compounds.

Regulation of fructose 2,6-bisphosphate levels in Neurospora crassa.

Both wild type and cr-1 mutant (adenylate cyclase and cyclic AMP-deficient) strains of Neurospora crassa contain fructose 2,6-bisphosphate at levels of 27 nmol/g dry tissue weight. This level decreases by about 50% in both strains upon depriving the cells of carbon or nitrogen sources for 3 h. An increase in cyclic AMP levels produced by addition of lysine to nitrogen-starved cells produced no increase in fructose 2,6-bisphosphate levels. Both strains respond to short-term addition of salicylate, acetate, or 2,4-dinitrophenol with an increase in fructose 2,6-bisphosphate. Thus, the above-described regulation of fructose 2,6-bisphosphate levels is cyclic AMP-independent. A suspension of the wild type produces a transient increase of fructose 2,6-bisphosphate in response to administration of glucose, whereas the mutant strain does not respond unless it is fed exogenous cyclic AMP. Substitution of acetate for sucrose as a sole carbon source for growth leads to a differential decrease in fructose 2,6-bisphosphate levels between the two strains: the wild type strain has 63% and the cr-1 mutant strain has 37% of the levels of fructose 2,6-bisphosphate on acetate as compared to sucrose-grown controls. This may be the basis for an advantage of cr-1 over wild type in growth on acetate. Thus, although most regulation of fructose 2,6-bisphosphate is cyclic AMP-independent, the levels can be regulated by a combination of carbon source and cyclic AMP levels.

The role of HBV-infection in development of cataracts in children and adults.

Possible role of intrauterine HBV infection in the formation of congenital non-hereditary cataracts is testified by discoveries of HBV markers in lens masses, aqueous humor of the anterior chamber and blood serum of the operated children and in blood of mother. We consider the patients with chronic diffuse liver diseases of HBV etiology to be a risk group of post capsular cataracts' formation. The development of these cataracts is associated with the progress of the basic liver disease. Among practically healthy persons, the initial lens changes are more often observed in carriers of australian antigen. Early signs of lens diseases in children and young or middle-aged adults determine the social meaning of this problem and reasons for the regular ophthalmologic check-up of patients with virus liver diseases and somatically healthy virus carriers.

[Clinical and immunological signs of retinal lesions and possibilities of their correction by drugs in patients with chronic diffuse liver diseases of viral etiology and carriers of Australia antigen]. / Kliniko-immunologicheskie priznaki porazheniia setchatki i vozmozhnosti ikh farmakokorrektsii u bol'nykh s khronicheskimi diffuznymi zabolevaniiami pecheni virusnoi étiologii i nositelei avstraliiskogo antigena.

A total of 133 subjects aged 15 to 55 were followed up, the main group (n = 87), patients with chronic diffuse diseases of the liver caused by hepatitis B virus, and two reference groups, 26 patients with uveitis and 20 normal subjects, 13 and 4 subjects of each group, respectively, were Australian antigen (HBsAg) carriers. Functional disorders of the retina were detected in 93.2% of group 1 patients, as well as intensified local (tears) and total system (blood) autoimmune reactions to tissue-specific retinal S-antigen (mol.mass 48 kD). An increased detection rate of antibodies to S-antigen and its higher titers were found in healthy virus carriers as compared to HBsAg-seronegative donors. These data may be regarded as evidence of an increased risk of uveoretinal pathology in subjects infected with hepatitis B virus, this being confirmed by a higher incidence (50%) of latent virus carriership in the group of patients with uveoretinitis. Stabilizing effect of cavinton in functional changes of the retina was revealed, this recommending this drug for combined therapy of patients with chronic diffuse diseases of the liver and for prevention of ocular diseases. The majority of the examinees in whom retinal abnormalities were found being young, the authors draw attention to the social aspect of the problem.

[Viral hepatitis B as a factor in the etiology of cataracts in adults and children]. / Virusnyi gepatit B kak faktor formirovaniia katarakt u vzroslykh i detei.

Vacuoles, aqueous fissures, crumb-like opacities, color iridescence, and thickening under the posterior capsule in the lens were found in 86% of 45 patients with chronic active hepatitis B, mean age 33 +/- 2.5 years. Seven percent of patients developed posterior capsule cataracts. examinations of 42 patients with cirrhosis of the liver caused by hepatitis B virus (mean age 39 +/- 2 years) revealed changes in the lens in 100% and mature cataracts in 36% of the eyes. In 2 of the 4 healthy HBsAg carriers aged 31 to 35 initial changes in the lens and accumulation of antilenticular antibodies in the lacrimal fluid and serum. A reliable difference by all the tested parameters between the examinees and controls (HBsAg-negative age-matched blood donors, n = 20) confirms a relationship between hepatitis B infection and lenticular abnormalities in subjects of a productive age. Markers of hepatitis B virus (HBsAg, HBeAg, anti-HBs, anti-HBe, anti-HBc) were found in the lenticular mass and blood sera of 11 out of 14 children aged 1.5 to 4 operated on for congenital nonhereditary cataracts; in 4 of them viral replication still continued. HBV markers of chronic viral carriership or markers of potential contagiousness were found in the sera of their mothers (in 6 and 5 sera, respectively), this indicating a possible intrauterine infection of children. The findings evidence a possible etiological role of hepatitis B virus infection in the formation of congenital and early acquired cataracts.