Achlya

Synthesis of polyoxysteroids of Achlya (steroid y- and 8-lactones) 98KPS3. 

Antheridiol.—The structure determination of antheridiol (100), the first specifically functioning steroidal sex hormone to be found in the plant kingdom which, when secreted by the female mycelia of the aquatic fungus Achlya bisexualis, initiates sexual reproduction, has been rapidly followed by its synthesis. Aldol condensation of ethyl 3,4-dimethylpent-2-enoate with the aldehyde (96) produced the unsaturated lactone (98) which could be op>ened to the dienic acid (99) with... 

Some of the enzymes from lower fungi, investigated by L John, are modulated by purine nucleotides, but generally in a different way from the regulation of GDH s from animal sources for example, whereas GDH s from Achlya and Saprolegnia are only weakly affected by purine nucleotides at concentrations of about 1 mM, that from Pythium is completely inhibited, in the direction of oxidative deamination, by 1 mM AMP (25). 

The first specific functioning sex hormone to be identified in the plant kingdom. A diffusible substance secreted by the female mycelium of the filamentous water molds Achlya bisexualis and A- ambisexuaiis, which induces... 

The values are expressed as a percentage of control s radial diameter obtained 3 to 12 days (depending on species) following inoculation with a Sima plug. A - P. cactorum without added cholesterol, B - P. cactorum with added cholesterol, C -Gibberella fujikuroi. D - Saproleania ferax. E - Achlya bisexualis, male strain, P - Achlva bisexualis. female strain. 

Achlya and Saproleania may, like P. cactorum. utilize sterols in a sparking and bulk role during vegetative growth. As a result, each of the 4 end products may ekhibit nonequivalent functions. 

Acetyl coenzyme A, formation, 45 Achlya, sterol utilization, 318,321 Aohlya ambisexualis. growth inhibition, 337 Achlya carolinlana. growth inhibition, 337... 

The initiation or arrest of enzyme synthesis responsible for the peak of ribonucleotide reductase is discussed below. Other factors which may modulate the activity in vivo or when measured in crude homogenates include allosteric control by the endogenous deoxyribonucleotides, the action of late S phase-specific inhibitors like the one found in Achlya, or the redox status of thioredoxin and glutaredoxin however the cell cycle dependence of these reactions is little known. It is therefore desirable to assay ribonucleotide reductase in preparations which have been subjected to at least one precipitation and dialysis step. While reliable cell cycle-dependent activity data are thus obtained, the absolute figures are frequently an order of magnitude too low to account for the cell s need of ribonucleotide reduction for DNA synthesis. This unsatisfactory condition is most likely a problem of quinary enzyme structure (see below) but is not felt to invalidate the accumulated evidence for tight correlation of ribonucleotide reduction and the cell cycle as a whole. 

There is a genus of water molds called Achlya that uses chanicals transmitted between male and female to synchronize their reproduction. There are four ch icals involved and each causes a spedlic behavior to occur in the proper sequence. 

The fungus Achlya (male strain) secretes a hormone oogoniol which causes the female strain to form egg-bearing branches. This hormone is a steroid, with oxygen atoms attached to the 7- and 15-positions, (McMorris etaL, 1975). 

Achlya bisexualis Saprotroph Oomycota Agar media with added heavy metals Box counting )bs = 1-26-1.6 [31]... 

Lundy, S.D., Payne, R.J., Giles, K.R. and GarriU, A. (2001). Heavy metals have different effects on mycelial morphology of Achlya bisexualis as determined by fractal geometry. FEMS Microbiol. Lett., 201, 259-263. 

A second hormone, produced by the male hyphae, has been shown to be a mixture of oogoniols 1 and 2 (44 and 45). These steroidal compounds are active at 620 and 460 ng/ml, respectively. Cultures of Achlya ambisexualis produced oogoniols only after treatment with antheridiol. Antheridiol appears to induce the formation of an enzyme necessary for the production of oogoniols (Mascarenhas, 1978 O Day and Horgen, 1981). 

Labeling studies with [3- H]-fucosterol (46) (the major sterol of Achlya) indicate that antheridiol and oogoniols 1 and 2 are derived from this compound. 

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