The effect of monochromatic radiation in the range 350 to 750 nm on the carotenogenesis in Verticillium agaricinum

An action spectrum for carotenogenesis in V. agaricinum has maxima at 395, 433, 660 and 737 nm. In a previous study it had been shown that a light-minus-dark difference spectrum of a crude extract from V. agaricinum had maxima at 390 and 420 nm, and furthermore a red, far-red interaction suggesting phytochrome involvement has been proposed. All these data suggest that there may be at least two photoreceptor systems operating in the photoinduction process here; one for the near-ultraviolet (UV-A)-mediated carotenogenesis, presumably a novel pigment, and the other for the red, far-red region, most likely phytochrome.     

Produits neutres et alcaloides de Myrtopsis macrocarpa,M. myrtoidea,M. novae-caledoniae et M. sellingii

Stems and leaves of Myrtopsis macrocarpa, M. myrtoidea, M. novae-caledoniae and M. sellingii yielded terpenes, sterols, coumarins, alkaloids (furoquinolines and quinolones) and amides. A new quinolone (8-methoxy flindersine) occurs in Myrtopsis macrocarpa, a new amide (N-benzoyltryptamine) in M. myrtoidea, two new coumarins (myrsellin and myrsellinol) and a new dihydrofuroquinoline (myrtopsine) in M. sellingii. Structures of the new compounds are proposed from chemical and spectroscopic evidence.     

Adjuvant BCG immunotherapy for stage I and II malignant melanoma.

Initial adjuvant immunotherapy trials have demonstrated a greater disease-free interval in patients treated with bacille Calmette-Guérin (BCG) compared with historical controls. In this study 149 patients at high risk of recurrence after surgical treatment of local or regional malignant melanoma were given BCG for 2 years and were followed up for a median of 28 months from the start of immunotherapy. The 36 patients in the comparison group had a higher rate of recurrence than the patients treated with BCG, and the rate in the treatment group was close to that reported from a similar study at the University of California at Los Angeles. The relatively long disease-free interval for the high-risk comparison patients in this study suggests that the control groups at other centres may have included patients with unrecognized additional risk. The rates of survival in the Canadian treatment group were also comparable to those reported by other centres. However, reports of a favourable BCG-mediated pattern of recurrence could not be confirmed. Therefore, the routine use of adjuvant BCG immunotherapy is not recommended.     

Cowpea Rhizobia Producing Dark Nodules: Use in Competition Studies

During a program of screening rhizobia from West Africa, it was found that some strains produced nodules of unusually dark appearance on cowpeas, but not on peanuts, soybeans, pigeon peas, or mung beans. The dark pigmentation was in the bacteroid zone, was not correlated with nodule effectiveness, and was additional to the leghemoglobin pigment. Only rhizobial strains with a nongummy (“dry”) colony morphology produced dark nodules. Visually distinguishable pink and dark nodules formed on the same root when a mixture of pink and dark strains was applied as inoculum. The dark-nodule phenotype was therefore appraised as a marker and found to be useful for studying nodulation competition with strains of the orthodox pink-nodule type. The competitiveness of 10 pink-nodule strains was examined relative to a black-nodule strain, IRc 256; a range of competitiveness was obtained of less competitive than, equally competitive to, or more competitive than IRc 256. Patterns of primary (early) nodulation were generally the same as patterns of secondary (later) nodulation. Mixed infections by dark and pink strains produced piebald nodules, the frequency of occurrence of which was much greater among primary than among secondary nodules.     

Sulfate Reduction and Methanogenesis in the Sediment of a Saltmarsh on the East Coast of the United Kingdom

The rates of sulfate reduction, methanogenesis, and methane loss were measured in saltmarsh sediment at monthly intervals. In addition, dissolved methane and sulfate concentrations together with pS²⁻ and pH were determined. Methane formation from carbon dioxide, but not from acetate, was detected within the same horizon of sediment where sulfate reduction was most active. Sulfate reduction was about three orders of magnitude greater than annual methanogenesis. The two processes were not separated either spatially or temporally, but occurred within the same layer of sediment at the same time of the year. Their coexistence did not seem to be the result of sulfate-depleted microenvironments within which methanogenesis could occur, but the methanogenic bacteria persisted at very low rates of activity within the same environment as the sulfate reducers.     

Studies on dehydro-l-ascorbic acid 2-arylhydrazone 3-oximes: Conversion into substituted triazoles and isoxazolines

l-threo-2,3-Hexodiulosono-1,4-lactone 2-(arylhydrazones) (2) were prepared by condensation of dehydro-l-ascorbic acid with various arylhydrazines. Reaction of 2 with hydroxylamine gave the 2-(arylhydrazone) 3-oximes (3). On boiling with acetic anhydride, 3 gave 2-aryl-4-(2,3-di-O-acetyl-l-threo-glycerol-l-yl)-1,2,3-triazole-5-carboxylic acid 5,4¹-lactones (4). On treatment of 4 with liquid ammonia, 2-aryl-4-(l-threo-glycerol-l-yl)-1,2,3-triazole-5-carboxamides (5) were obtained. Acetylation of 5 with acetic anhydride-pyridine gave the triacetates, and vigorous acetylation with boiling acetic anhydride gave the tetraacetyl derivatives. Periodate oxidation of 5 gave the 2-aryl-4-formyl-1,2,3-triazole-5-carboxamides (8), and, on reduction, 8 gave the 2-aryl-4-(hydroxymethyl)-1,2,3-triazole-5-carboxamides, characterized as the monoacetates and diacetates. Controlled reaction of 2 with sodium hydroxide, followed by neutralization, gave 3-(l-threo-glycerol-l-yl)-4,5-isoxazolinedione 4-(arylhydrazones), characterized by their triacetates. Reaction of 2 with HBr-HOAc gave 5-O-acetyl-6-bromo-6-deoxy-l-threo-2,3-hexodiulosono-1,4-lactone 2-(arylhydrazones); these were converted into 4-(2-O-acetyl-3-bromo-3-deoxy-l-threo-glycerol-l-yl)-2-aryl-1,2,3-triazole-5-carboxylic acid 5,4¹-lactones on treatment with acetic anhydride-pyridine.     

The polysaccharides of the brown seaweed Turbinaria murrayana

Polysaccharides of the brown seaweed Turbinaria murrayana were isolated. Laminaran (3.2%) was isolated from the hot-water extract of the algae by using ion-exchange chromatography. Fucans (2.1%) were isolated from the hot-water extract, as well (4.7%) as from the extract of the algae with dilute acid. Acid hydrolsysis of the isolated fucans revealed glucose, amnnose, fucose, glucuronic acid, xylose, and galactose. Alginic acid (22.6%) was separated, and reduced to a neutral polysaccharide. The polysaccharides isolated were analyzed by methylation and Smith degradation.     

Effect of the organophosphorous insecticide, chlorpyrifos (Dursban), on growth, fecundity and mortality of Biomphalaria alexandrina and on the production of Schistosoma mansoni cercariae in the snail.

Exposure of Biomphalaria alexandrina to sublethal concentrations (0.125, 0.25 and 0.05 ppm) of the organophosphorous insecticide, chlorpyrifos (Dursban), induced a reduction in egg production and egg hatchability. Exposure of Schistosoma mansoni miracidia to the insecticide (60 min, 0.50 ppm) prior to infection of B. alexandrina did not affect the subsequent production of cercariae. However, exposure of S. mansoni-infected snails to the insecticide until day 55, from day 20 to day 62 and from day 35 to 62 following infection resulted in blockage of cercarial shedding. Cercarial shedding commenced in some snails when the treatment stopped. Exposure to the insecticide in concentrations of 0.125 and 0.25 ppm during the first 20 days following infection did not affect the subsequent production of cercariae, but exposure to 0.5 ppm during the first 20 days affected markedly the production of cercariae due to a high snail mortality. The findings indicate that the cercaria is the target stage for the activity of chlorpyrifos on the intramolluscan larval development. It is suggested that S. mansoni cercarial production in B. alexandrina may be a useful system for monitoring the effect of low concentrations of pesticides on the aquatic environment, and that the ability by chemical means to interrupt the cercarial production might be a useful tool in further analyses of important aspects of the snail/parasite relationship.     

13C isotope discrimination correlates with biological nitrogen fixation in soybean (Glycine max (L.) Merrill)

Ammonium sulphate was applied at the rate of 300 kg N ha^–1 with or without the nitrification inhibitor 1-carbamoyl-3(5)-methylpyrazol (4 kg ha^–1) to plots measuring 1.5 × 1.5 m. The fertilizer and the inhibitor were washed into the top 15-cm layer of the soil, which was highly calcareous (55% CaCO₃), and the plots were kept bare. The process of nitrification was monitored by regular soil sampling. In the absence of the inhibitor, nitrification was completed in three weeks. In the presence of the inhibitor only 10% of applied N was nitrified by the end of the third week and 42% by the end of the eighth week. Average soil temperature at 5–, 10– and 20-cm depth over the first six weeks was 26.0, 24.8 and 24.2°C, respectively.