Three further naphthoquinones produced by Fusarium solani

Three naphthoquinone pigments are described which were produced by Fusarium solani. They are 2,3-dihydro-5,8-dihydroxy-6-methoxy-2-hydroxymethyl-3-(2-hydroxypropyl)-1,4-naphthalenedione, 2,3-dihydro-5-hydroxy-4-hydroxymethyl-8-methoxy-naphtho[1,2-b]furan-6,9-dione and 5,8-dihydroxy-2-methoxy-6-hydroxymethyl-7-(2-hydroxypropyl)-1,4-naphthalenedione. One of these pigments was shown to be the precursor of the other two.     

Clues from Xanthomonas campestris about the evolution of aromatic biosynthesis and its regulation

The recent placement of major Gram-negative prokaryotes (Superfamily B) on a phylogenetic tree (including, e.g., lineages leading to Escherichia coli, Pseudomonas aeruginosa, and Acinetobacter calcoaceticus) has allowed initial insights into the evolution of the biochemical pathway for aromatic amino acid biosynthesis and its regulation to be obtained. Within this prokaryote grouping, Xanthomonas campestris ATCC 12612 (a representative of the Group V pseudomonads) has played a key role in facilitating deductions about the major evolutionary events that shaped the character of aromatic biosynthesis within this grouping. X. campestris is like P. aeruginosa (and unlike E. coli) in its possession of dual flow routes to both L-phenylalanine and L-tyrosine from prephenate. Like all other members of Superfamily B, X. campestris possesses a bifunctional P-protein bearing the activities of both chorismate mutase and prephenate dehydratase. We have found an unregulated arogenate dehydratase similar to that of P. aeruginosa in X. campestris. We separated the two tyrosine-branch dehydrogenase activities (prephenate dehydrogenase and arogenate dehydrogenase); this marks the first time this has been accomplished in an organism in which these two activities coexist. Superfamily B organisms possess 3-deoxy-D-arabino-heptulosonate 7-P (DAHP) synthase as three isozymes (e.g., in E. coli), as two isozymes (e.g., in P. aeruginosa), or as one enzyme (in X. campestris). The two-isozyme system has been deduced to correspond to the ancestral state of Superfamily B. Thus, E. coli has gained an isozyme, whereas X. campestris has lost one. We conclude that the single, chorismate-sensitive DAHP synthase enzyme of X. campestris is evolutionarily related to the tryptophan-sensitive DAHP synthase present throughout the rest of Superfamily B. In X. campestris, arogenate dehydrogenase, prephenate dehydrogenase, the P-protein, chorismate mutase-F, anthranilate synthase, and DAHP synthase are all allosteric proteins; we compared their regulatory properties with those of enzymes of other Superfamily B members with respect to the evolution of regulatory properties. The network of sequentially operating circuits of allosteric control that exists for feedback regulation of overall carbon flow through the aromatic pathway in X. campestris is thus far unique in nature.     

Translational regulation of light-induced ribulose 1,5-bisphosphate carboxylase gene expression in amaranth.

The regulation of the genes encoding the large and small subunits of ribulose 1,5-bisphosphate carboxylase was examined in amaranth cotyledons in response to changes in illumination. When dark-grown cotyledons were transferred into light, synthesis of the large- and small-subunit polypeptides was initiated very rapidly, before any increase in the levels of their corresponding mRNAs. Similarly, when light-grown cotyledons were transferred to total darkness, synthesis of the large- and small-subunit proteins was rapidly depressed without changes in mRNA levels for either subunit. In vitro translation or in vivo pulse-chase experiments indicated that these apparent changes in protein synthesis were not due to alterations in the functionality of the mRNAs or to protein turnover, respectively. These results, in combination with our previous studies, suggest that the expression of ribulose 1,5-bisphosphate carboxylase genes can be adjusted rapidly at the translational level and over a longer period through changes in mRNA accumulation.     

Anaerobic biodegradation of phenolic compounds in digested sludge.

We examined the anaerobic degradation of phenol and the ortho, meta, and para isomers of chlorophenol, methoxyphenol, methylphenol (cresol), and nitrophenol in anaerobic sewage sludge diluted to 10% in a mineral salts medium. Of the 12 monosubstituted phenols studied, only p-chlorophenol and o-cresol were not significantly degraded during an 8-week incubation period. The phenol compounds degraded and the time required for complete substrate disappearance (in weeks) were: phenol (2), o-chlorophenol (3), m-chlorophenol (7), o-methoxyphenol (2), m- and p-methoxyphenol (1), m-cresol (7), p-cresol (3), and o-, m-, and p-nitrophenol (1). Complete mineralization of phenol, o-chlorophenol, m-cresol, p-cresol, o-nitrophenol, p-nitrophenol, and o-, m-, and p-methoxyphenol was observed. In general, the presence of Cl and NO2 groups on phenols inhibited methane production. Elimination or transformation of these substituents was accompanied by increased methane production, o-Chlorophenol was metabolized to phenol, which indicated that dechlorination was the initial degradation step. The methoxyphenols were transformed to the corresponding dihydroxybenzene compounds, which were subsequently mineralized.     

Relationship of seminal vesicle size and measures of libido in yearling beef bulls

Ninety-five yearling beef bulls were given routine Breeding Soundness Examinations, two libido tests and palpated rectally for internal genital disease and measurement of seminal vesicle size. Finger tips were premeasured, and then used as "glandometers". The bulls were examined at the end of a 140-day performance test. Sixteen lines of breeding were examined including 13 Hereford, 2 Angus and 1 Red Angus. Average age was 384 days and average weight was 961 lbs. Line and breed differences (P<.05) were observed for scrotal circumference, scrotal circumference score and second libido test. Similar differences were observed for SV length (P<.01), depth and volume both (P<.05). There were no significant correlations between seminal vesicle (SV) size and libido scores. There were, however, significant correlations between SV size and scrotal circumference (P<.05), BSE score (P<.01), body weight (P<.01), and semen morphology score (P<.05). Proximal droplets and midpiece abnormalities, respectively, were the most common spermatozoal abnormalities observed in semen from this group of bulls.     

Effect of tryptophan and selected analogues on body temperatur of endotoxin-poisoned mice

The effect of endotoxin on the body temperature of mice was studied in animals housed without bedding at an environmental temperature of 15 C. Rectal temperatures were measured during the initial 3 to 5 hr of exposure. Doses of endotoxin ranging from 0.01 to 1 ld(50), as determined for mice maintained at 25 C, produce a hypothermia in proportion to dose. Concurrent injection of tryptophan magnified this response in a dose-dependent manner. Cyproheptadine, an antiserotonin drug, antagonized both the hypothermia produced by serotonin alone, and the augmentation of hypothermia produced by tryptophan in endotoxin-poisoned mice. alpha-Methyltryptophan, an analogue of the amino acid that is known to induce tryptophan pyrrolase, also antagonized the increased hypothermia produced by tryptophan. These data support a previous suggestion that inhibition of tryptophan pyrrolase in endotoxin-poisoned mice has the effect of funneling injected tryptophan into the serotonin pathway.