Correlation of cotylenol with the aglycone of fusicoccin

The stereostructure of cotylenol, the aglycone of the cotylenins, has been confirmed by chemical correlation with the aglycone of fusicoccin A.     

Freeze-preservation of rice cells: A physiological study of freeze-thawed cells

Rice ( Oryza sativa L.) cells returning to in vitro culture after preservation at superlow temperature in liquid nitrogen are characterized by a number of physiological alterations. These include: reduction in respiration and glucose uptake, loss of intracellular potassium, decrease in the cellular level of key metabolites (ATP, glucose-6-phosphate and pyruvate) and fragility of protoplasts following the action of cell wall-degrading enzymes.
Nevertheless, cell growth resumes after a short lag phase (2–4 days) with an actual 70–100% cell survival, thus indicating that the observed damage is not lethal and can be repaired in a short time.     

The molecular basis of disorders of human hemoglobin synthesis

Summary The structure and organization of the human globin genes at the nucleotide level has been established by restriction endonuclease digestion of cellular DNA, and by the isolation and purification of these. genes in phage vectors. With this approach it has been possible to define alterations at the DNA level resulting in a group of inherited diseases of man known as the thalassemia syndromes, and related disorders. Combined with other known genetic and biochemical data, these studies provide a framework for understanding the pathogenesis of these disorders at the molecular level.     

Sterols from three Lactarius species

The sterol composition of three fungi was determined. Ergosterol is the major sterol, accompanied by other closely related sterols.     

Enhanced erythroid burst formation in mice after testosterone treatment

A single administration of testosterone propionate (TP) in ex-hypoxic polycythemic mice induces, at 24 hr after androgen, an amplification of the erythroid burst-forming unit (BFU-E or B) pool in marrow. This phenomenon is not associated with an amplification of the erythroid colony-forming unit (CFU-E or E) compartment and is followed by its depletion. In the other hand, the 36–49 hr rise of erythropoietin (Ep) levels in serum is followed by a 60-hr amplification of the E pool. It is suggested that the latter phenomenon is mediated by enhanced Ep production, whereas the early amplification of the B compartment may derive from a direct influence of TP at the stem cell level.     

Amino acid composition of zein molecular components

Zein extracted from maize endosperm has been fractionated into four polypeptide chains, having the following MWs 23 000, 21 000, 13 500 and 9600. By amino acid analysis the two smaller MW chains (representing 30% of total zeins) have been found to be zein-type molecules. These two chains are thought to be responsible for zein granule formation via -S-S- bridges. Zein is also highly heterogeneous in charge, and is resolved into at least 15 components, with pI's in the pH range 5–9. As demonstrated by amino acid analysis, part of this heterogeneity is due to spot mutations in some of the genes responsible for zein synthesis.     

MK-801 Prevents 1-Methyl-4-Phenyl-1,2,3,6-Tetrahydropyridine-Induced Parkinsonism in Primates

In cynomologus monkeys, systemic administration of MK-801, a noncompetitive antagonist for the N-methyl-D-aspartate receptor, prevented the development of the parkinsonian syndrome induced by the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). MK-801 also attenuated dopamine depletion in the caudate and putamen and protected dopaminergic neurons in the substantia nigra from the degeneration induced by the neurotoxin. Nevertheless, 7 days after MPTP administration in the caudate and putamen of monkeys also receiving MK-801, the levels of toxic 1-methyl-4-phenylpyridinium were even higher than those measured in monkeys receiving MPTP alone. This indicates that the protective action of MK-801 is not related to MPTP metabolism and strongly suggests that, in primates, the excitatory amino acids could play a crucial role in the mechanism of the selective neuronal death induced by MPTP.     

The R1 gene conferring race-specific resistance to Phytophthora infestans in potato is located on potato chromosome V.

Summary Late blight in potato is caused by the fungusPhytophthora infestans and can inflict severe damage on the potato crop. Resistance toP. infestans is either based on major dominantR genes conferring vertical, race-specific resistance or on minor genes inducing horizontal, unspecific resistance. A dihaploid potato line was identified which carried theR1 gene, conferring vertical resistance to allP. infestans races, with the exception of those homozygous for the recessive virulence allele of the locusV1. The F₁ progeny of a cross between this resistant parent P(R1) and P(r), a line susceptible to all races, was analysed for segregation ofR1 and of restriction fragment length polymorphism (RFLP) markers distributed on the potato RFLP map comprising more than 300 loci. TheR1 locus was mapped to chromosome V in the interval between RFLP markers GP21 and GP179. The map position ofR1 was found to be very similar to the one ofRx2, a dominant locus inducing extreme resistance to potato virus X.     

Isolation of cytochalasins A and B fromAscochyta lathyri

The possible presence of toxic metabolites in the culture extracts of 24Ascochyta strains, grown on autoclaved wheat, was ascertained by the use of the biological assay on brine shrimps (Artemia salina). Only in the culture extract ofA lathyri, that showed a very high toxicity, the presence of cytochalasins A and B was revealed by tlc,¹H nmr and fab-mass spectra. SinceA heteromorpha, previously described as the firstAscochyta species to produce cytochalasins, has been reclassified asPhoma exigua varheteromorpha, this is therefore the first report on the cytochalasin production by a trueAscochyta species.     

The human ryanodine receptor gene: Its mapping to 19q13.1, placement in a chromosome 19 linkage group, and exclusion as the gene causing myotonic dystrophy

The recent cloning of cDNA encoding the Ca++ release channel (ryanodine receptor) of human sarcoplasmic reticulum has enabled us to use somatic cell hybrids to localize the ryanodine receptor gene (RYR) to the proximal long arm of human chromosome 19. Studies with additional hybrids containing deletions or translocations in chromosome 19 enabled us to localize RYR to 19q13.1 in a region distal to GPI/MAG and proximal to D19S18/DNF11. On the basis that the myotonic dystrophy (DM) locus maps near this region and that myotonia could result from a defect in the ryanodine receptor, we examined the linkage between the DM locus and RYR. Our results, showing several DM-RYR recombinants, rule out an RYR defect as the cause of DM. However, localization of RYR to a region of human chromosome 19 which is syntenic to an area of pig chromosome 6 containing the HAL gene responsible for porcine malignant hyperthermia supports the candidacy of RYR for this disorder.