Jerry A. Cooper

Role of phenolic compounds in the antialgal activity of barley straw

Barley straw decomposing in well-aerated water releases a substance(s) that inhibits algal growth. Phenolic compounds are toxic to algae but are unlikely to be present in sufficient quantities to account for the extended antialgal action of straw. However, straw is antialgal under conditions that may promote oxidation of phenolic hydroxyl groups to quinones; tannins are antialgal under similar conditions. The toxicity of authentic quinones towardsMicrocystis is confirmed; the quinones are some 103 times more antialgal than phenolic acids. The possibility that oxidized lignin derivatives may be involved in straw toxicity towards algae is discussed.

Barley straw as an inhibitor of algal growth III: the role of fungal decomposition

Rotting barley straw, which is known to inhibit algal growth, has been subjected to mycological examination. A wide range of fungi was isolated from submerged, aerated decomposing straw and tested for antialgal effects againstChlorella on agar plates. Three species, each the dominant isolate from different batches of straw, inhibited the alga. However, the general antialgal effects of decomposing straw are unlikely to be explained by antialgal properties of specific fungi.

Barley straw inhibits growth of some aquatic saprolegniaceous fungi

Abstract Barley straw rotting in water under aerobic conditions controls the growth of both algal and cyanobacterial species and is exploited as a method to control nuisance algae. We report here the effect of anti-algal straw on isolates of an aquatic fungus that comprises a significant component of the freshwater aquatic ecosystem and causes a major fungal disease in fish and other aquatic animals. In a laboratory bioassay, straw, at dose rates comparable to those which inhibit algal growth, stopped the mycelial growth of isolates of two species of Saprolegnia, S. parasitica and S. diclina ; S. ferax was less inhibited. Inhibition in the laboratory bioassay was also recorded at the lower dose rate at which straw is widely used in environmental algal control programmes. We suggest that straw may ameliorate symptoms of saprolegniasis in fish, but it is not clear whether straw can prevent the rapid spread of the fungus in hatcheries.

New Zealand hyphomycete fungi: Additional records, new species, and notes on interesting collections

Abstract Thirty‐eight species of micro‐fungi are described as newly recorded in New Zealand. These fungi are mainly found in association with a specific exotic host, Quercus ilex, or the hitherto uninvestigated ecological group of aero‐aquatic fungi. Six are described as new: Bactrodesmium nothofagi, Dactylaria leptospermi, Pleurothecium leptospermi, Polyscytalum ciliatum, Pseudoclathrosphaerina spiralis, and Zanclospora ureweri. An existing invalid name in the literature, Pseudaegerita foliicola, is provided with a validating description. Keys are provided to the genera Pseudaegerita, Thozetella, and aero‐aquatic fungi with helicoid, non‐wettable or air‐trapping propagules.

Molecular phylogeny and global diversity of the remarkable genus Bondarzewia (Basidiomycota, Russulales)

Bondarzewia is a remarkable polypore genus due to its relatively large poroid basidiocarps and belongs to order Russulales according to recent phylogenetic analyses. Two species, B. berkeleyi and B. mesenterica, are commonly reported in North America and Europe but the genus is poorly known elsewhere. We explored the phylogeny and species diversity of Bondarzewia based on a larger number of samples covering a wider geographic range, including eastern Asia, Europe, North America, Oceania and South America. Sequences were generated from the nuc rDNA region encompassing the internal transcribed spacers 1 and 2, along with the 5.8S rDNA (ITS) and nuc 28S rDNA D1-D2 domains (28S), and the final dataset included 28 samples of which 21 ITS and 28S sequences were newly generated. As a result of phylogenetic analyses and comparison of morphological features we propose a new classification of the genus recognizing 10 species. Most of the novel taxonomic concepts are geographically restricted in contrast to the past broad species concepts, especially of B. berkeleyi. In addition, a degree of host specificity is observed with B. mesenterica, B. occidentalis, B. podocarpi, B. propria and B. submesenterica apparently restricted to gymnosperms and all others on angiosperm hosts where known. Three new species, B. kirkii, B. occidentalis and B. submesenterica, are described and illustrated. Three new combinations (B. dickinsii, B. propria, B. retipora) are revived from synonymy under B. berkeleyi. A key to known species of Bondarzewia is provided.

Stable free radical from plant litter decomposing in water

The presence of a stable radical species in both fresh straw and that which had been submerged in aerated water for up to six months has been demonstrated using electron paramagnetic (spin) resonance (EPR or ESR) spectroscopy. A radical signal was associated also with material shown to contain straw lignin markers, which was leached from the rotting straw into surrounding water. Fresh straw treated with strong alkali to remove phenolics did not show a radical signal. The possible effect of a dissolved stable free radical is discussed in relation to the antagonistic effect of rotting straw on algal and cyanobacterial growth in water to which straw has been added as a nuisance algal control agent.

A spherical capacitance transducer for ultrasonic displacement measurements in NDE

A capacitance transducer is described which is particularly suitable for the measurement of ultrasonic surface acoustic transients. The transducer has a small spherical electrode in a simple construction which is straightforward to use in comparison with other designs. A typical transducer has been compared experimentally with a parallel-plate capacitance probe using laser-generated acoustic transients as a standard source. The transducer is shown to have a frequency response in excess of 5 MHz with a sensitivity of 1.5 mV nm-1 for Rayleigh surface transients a few nanometres in amplitude.

Psathyloma, a new genus in Hymenogastraceae described from New Zealand

A new genus Psathyloma is described based on collections of agarics from New Zealand. We describe two new species in the genus, Ps. leucocarpum and Ps. catervatim, both of which have been known and tentatively named for a long time awaiting a formal description. Morphological traits and phylogenetic analyses reveal that Psathyloma forms a strongly supported sister clade to Hebeloma, Naucoria and Hymenogaster. Morphologically Psathyloma resembles Hebeloma from which it differs mainly by producing smooth basidiospores with a germ pore. The geographical range of the genus has been demonstrated to include several regions in the southern hemisphere. A survey of published environmental sequences reveals that Psathyloma spp. were isolated from ectomycorrhizal root tips from Tasmania and Argentina, indicating an ectomycorrhizal association with southern beech.

Nomenclature - Formal reports, proposals, and opinion

Formal proposals to conserve or protect fungal names as well as proposals to amend the International Code of Nomenclature of immediate interest to mycologists are now published concurrently in Mycotaxon and Taxon. Conservation proposals include Prop. 1918 (to conserve the name Dermatocarpon bucekii against Placidium steineri), Prop. 1919 (to conserve the name Lactarius with a conserved type), Prop. 1926 (to conserve the name Cladia against Heterodea, and Prop.1927 (to conserve the name Agaricus rachodes with that spelling). Props. 117-119 to amend the Code ask for pre-publication deposit of nomenclatural information in a recognized repository for valid publication of fungal names.

CRACK DEPTH ESTIMATION USING WIDEBAND LASER GENERATED SURFACE ACOUSTIC WAVES

Following previous studies where we analysed the physics of laser generated acoustic waves in metals, techniques have been developed using these acoustic waves which permit flaw detection in metal surfaces. The laser generated surface waves are used in conjunction with transducers to both locate and estimate the depth of surface breaking cracks. The results show that one of the advantages of the laser-acoustic source is that it generates transient ultrasonic pulses with a wide frequency bandwidth.