Calcium oxalate accumulation and soil weathering in mats of the hypogeous fungus Hysterangium crassum

Fungal mats of Hysterangium crassum (Tul. and Tul.) Fischer occupied a mean of 9.6% of the upper 10 cm of soil developed under a 40–65 yr old stand of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) in Oregon. This hypogeous basidiomycete exudes large amounts of oxalic acid, some of which precipitates with Ca in microscopic crystals of calcium oxalate, resulting in a mean CaC₂O₄ content of 82g m^?2 for the entire soil. Soil oxalate concentration was significantly greater within fungal mats (P < 0.01) and soil pH was significantly lower (P < 0.01) than in soil adjacent to mats. The quantity of Ca present as CaC₂O₄ is 0.5 the amount of exchangeable Ca in the soil and exceeds the mass of Ca lost annually in runoff. Scanning electron micrographs show intense chemical weathering, attributable to oxalate attack, in the immediate vicinity of hyphae. X-ray diffraction patterns of clay indicate bulk weathering is more intense within the fungal mats than in adjacent uncolonized soil.     

Interactions between bacteria and ectomycorrhizal fungi

Interactions between eight ectomycorrhizal fungi and eight bacteria were tested on five laboratory media and in the rhizoplane of Pinus radiata. Depression of growth of the fungi by the bacteria in laboratory media was dependent on the medium and bore little relation to effects in the rhizoplane. In the rhizoplane, different bacteria could depress, have no effect or even stimulate growth of mycorrhizal fungi. Competition and antagonism are suggested as mechanisms for depression of the fungi. Some bacteria gave protection against the depressive effects of other bacteria. Considerable differences occurred between ectomycorrhizal fungi in their colonization of the rhizoplane in the absence of bacteria and also in their presence. The common mycorrhizal fungi Rhizopogon luteolus and Thelephora terrestris generally colonized roots well but the strain of Pisolithus tinctorius studied colonized poorly. Direct microscopy showed the percentage cover of the root by microorganisms was usually only 10–20%.It is proposed that interactions of ectomycorrhizal fungi with soil organisms are important in determining the successful introduction and persistence of inoculated ectomycorrhizal fungi. Fungi should be selected for compatibility with a wide range of soil microflora as well as efficiency in plant stimulation.     

Distribution and partial characterisation of acid hydrolysable organic nitrogen in six New Zealand soils

Six New Zealand topsoils of widely different origins and properties were subjected to 6m HC1 hydrolysis and the distribution of N fractions and amino acids were determined qualitatively and quantitatively.Of the total-N in the soils studied 83–91%, was hydrolysable with 6m HCl. The largest proportion of the hydrolysable N was α-amino acid N (38– 42%). followed by hydrolysable-unknown N (HUN) (14–24%), and NH₄⁺-N (14–22%). A significant proportion (25–50%) of the HUN fraction was accounted for by the non α-amino acid-N. Oxidative (3% H₂O₂) hydrolysis released N-phenoxy amino acid-N and possibly N-compounds which were complexed with phenols and sugars. All soils had a similar amino-acid composition with a predominance of acidic amino-acids.     

Remarks on the anatomy and ontogeny of scales of teleosts. I

Densitometer records were made from the scales of a number of fish species, mainly from pikeperch. Analysis of the records showed that the pattern of hollows, representing the circuli in the curves, was very regular. No arrangement into groups of narrowly interspaced circuli could be demonstrated. It was therefore concluded that the circuli of the surface layer do not produce the “growth-checks”. Ringlike structures were also present in the fibrous basal plate. These were about 3–5 μm closer together than the circuli. These two circular gratings of slightly different inter-ring spacing will create an interference pattern, in this case a circular moiré pattern, having no direct relation to the structures present in the two layers forming the scale.     

Comparison of yeast and algal diets for bivalve molluscs

Four species of bivalve molluscs were fed diets consisting of varying proportions of the yeast Candida utilis and the diatom Thalassiosira pseudonana. Juvenile Argopecten irradians, Mercenaria mercenaria, and Mytilus edulis grew as fast or faster than controls when fed diets containing as much as 50% yeast. Growth of soft tissue in Crassostrea virginica, however, decreased with the amount of yeast in the diet. The relative food values of the different diets were not closely correlated with gross chemical composition or amino acid composition.     

Glugea heraldi n. sp. (Microsporida, Glugeidae) from the seahorse Hippocampus erectus Perry

Abstract. A new species of Microsporida, Glugea heraldi , is described from the seahorse Hippocampus erectus . Measurements of fixed spores and notes on the histopathology of parasitized tissue are given.     

Hepatomas in Atlantic tomcod Microgadus tomcod (Walbaum) collected in the Hudson River estuary in New York

Abstract. Incidental observations of Atlantic tomcod during routine laboratory processing revealed that a portion of the adult population collected during the 1977–78 spawning season had enlarged livers containing dark coloured tumours and other abnormalities. Of the total of 264 livers collected between 16 January and 27 February 1978 and grossly examined for prevalence of abnormalities, 25% appeared to contain neoplastic nodules and hepatocellular carcinoma. One liver contained a massive tumour (7 × 12 mm) that involved approximately 60% of the liver. The exact causes of the high prevalence of hepatocellular carcinoma are unknown but poly-chlorinated biphenyls (PCBs) are suspected of having a possible role. The Hudson River is known to contain elevated concentrations of PCBs. Twelve tomcod livers from the 1977–78 spawning population representing both normal and hepatoma conditions contained concentrations of PCBs ranging from 10–9 to 98–2 ppm (mean of 37–5 ppm).     

Cellular immune response in rainbow trout Salmo gairdneri Richardson to Yersinia ruckeri O-antigen monitored by the passive haemolytic plaque assay test

Abstract. The specificity and kinetics of the immune response of rainbow trout ( Salmo gairdneri ) to single injections of an O-antigen extracted from the bacterial pathogen Yersinia ruckeri , which causes enteric redmouth in fish, were investigated by the passive haemolytic plaque assay and serum antibody quantitation. Doses ranging from 5 ng to 500 mg in 10-fold increments were injected intraperitoneally into groups of trout held at 17 × 1°5°C. The occurrence of plaque forming cells (PFC) and humoral antibody was followed for 35 days after injection. Trout gave an immune response to doses of 500 ng and above. Seven days after injection no humoral antibody was detected, but PFC were found in the spleen. The maximum PFC numbers occurred 11 days after injection. On day 21, few PFC were found, whereas serum antibody titres were highest. The antibody from immunized trout showed little or no cross-reactions with sheep red blood cells passively labelled With antigens from other fish pathogens.     

Photoperiod induced off-season spawning of pink salmon (Oncorhynchus gorbuscha)

Four groups of pink salmon, which had been reared under artificial light, became sexually mature and produced viable gametes: 59 days prior to, and 19 – 32 days, 115 days and 220 days after their expected date of reaching sexual maturity. Altered times of sexual maturation were obtained by accelerating, leaving unchanged, or decelerating the rate of change of photoperiod which each group of fish would normally receive during its first year of life. All groups of fish were exposed to a normal rate of change in photoperiod during their final year of life. Mean fecundity was reduced from the 800–2000 ova observed in wild stocks, and ranged from 629 for the 59 day advanced fish, to 862 for the 115 day delayed fish. Egg mortality during the period from fertilization to eyeing was much greater in the three groups of fish subjected to accelerated or decelerated rates of change in photoperiod than in the fish subjected to the normal rate of change in photoperiod. Some of the progeny of the 220 day delayed fish, which were reared under artificial light with the normal rate of change in photoperiod set 220 days out-of-phase, became sexually mature 2 years after they had begun life as fertilized eggs.