Synaptic organisation and neuron microtubule distribution

Summary The microtubules in different parts of the neuron and synaptosomes were examined with respect to their stability, structure and orientation. On the basis of distribution, different labilities and differences in protofilament substructure seen by tannic acid staining, we have classified microtubules into eight major categories. Functional involvements in vesicle translocation, cytoskeletal support and the regulation of assembly/disassembly are considered.Dr. L.E. Westrum is an affiliate of the CDMRC at the University of Washington and a recipient of a Wellcome Research Travel Grant from the Burroughs-Wellcome Fund. The research was also supported in part by NIH Grants NS 09678, NS 04053 (NINCDS) and DE 04942 (NIDR), DHHS     

Revaluation of ortho-phosphorus and inorganic nitrogen levels in an antarctic meromictic lake

Recent studies of Lake Bonney, a meromictic Antarctic lake, utilized techniques modified for hypersaline waters and produced results significantly different from those of previous investigators. Notably higher values are reported for ammonia and nitrate, while phosphorus levels tend to be in distinct disagreement with those obtained by other workers except for limited data reported by one author using a technique similar to that used in the current studies. The method of standard additions was employed as a partial solution to salinity interferences.Correspondence: Bruce C. PARKER Biology Department, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061     

A new Thysanophora

Thysanophora striatispora is described as a new species of the genus. It is distinctive in that the spores have pronounced ridges running longitudinally down the spore giving it a fluted appearance in section. Sympodial proliferation of the conidiophore although present is not well developed in this species.

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Zusammenfassung Thysanophora striatispora ist als eine neue Art der Gattung beschrieben. Sie ist unterschiedlich, da die Sporen einen Furchenrain zeigen, der longitudinal auf der Spore verläuft und ihr das Aussehen einer Kannelüre verleiht. Die sympodiale Proliferation der Konidiophoren, obwohl vorhanden, ist in dieser Art nicht gut entwickelt.

     

Nematophagous fungi: three new species of Myzocytium.

Three species of Myzocytium parasitic on nematodes are described as new. In M. papillatum the zoospores encyst directly on the host cuticle before penetration. This species produces smooth, spherical oospores. In M. glutinosporum the biflagellate zoospores do not attack the host directly; after encystment they produce a spherical adhesive bud which allows the spores to adhere to the cuticle of passing nematodes. This species produces echinulate, spherical oospores. In M. anomalum the primary spores are aplanospores. After a dormant phase, and when suitably stimulated, these aplanospores change into biflagellate zoospores and the latter encyst on the host cuticle. No sexual state is known in this species. Persistence is by means of thick-walled, spherical chlamydospores.     

Scale Interactions and Regional Climate: Examples from the Susquehanna River Basin

One of the most difficult problems faced by climatologists is how to translate global climate model (GCM) output into regional- and local-scale information that health and environmental effects researchers can use. It will be decades before GCMs will be able to resolve scales small enough for most effects research, so climatologists have developed climate downscaling methods to bridge the gap between the global and local scales. There are two main streams of climate downscaling research. First, high-resolution, limited-area climate models can be embedded in the coarse-scale GCMs, producing much finer resolution climate data. Second, empirical downscaling techniques develop transfer functions linking the large-scale atmospheric circulation generated by the GCMs to surface data. Examples of both types of downscaling, aimed at improving projections of future climate in the Susquehanna River Basin (the Mid-Atlantic Region of the United States), are presented. A third case is also described in which an even higher-resolution nested atmospheric model is being developed and linked to a hydrologic model system, with the ultimate goal of simulating the environmental response to climate forcing at all time and space scales.     

Short communication: Ethanol production from cellulose at 45°C using a batch-fed system containing alginate-immobilized Kluyveromyces marxianus IMB3

The thermotolerant yeast, Kluyveromyces marxianus IMB3, was grown in batch culture at 45°C on cellulose-containing media, supplemented with exogenous cellulase activity. At various stages during fermentation, both substrate and enzyme were added in batch mode and fermentation was continued for 220 h. Ethanol production increased to 20 g/l at 200 h, representing 45% of the maximum theoretical yield. In subsequent experiments, the organism was immobilized in calcium alginate beads and these were used in a similar, batch-fed system at 45°C. Again, fermentation was continued for 220 h and ethanol production increased to its maximum, of 28 g/l, within 100 h and this represented in excess of 60% of the maximum theoretical yield.     

The gene expression sequence of radiated mucosa in an animal mucositis model

Abstract. Oral mucositis is a common, dose-limiting, acute toxicity of radiation therapy administered for the treatment of cancers of the head and neck. Accumulating data would suggest that the pathogenesis of mucositis is complex and involves the sequential interaction of all cell types of the oral mucosa, as well as a number of cytokines and elements of the oral environment. While a number of studies have reported on gene expression of particular cell types in response to radiation, the overall response of irradiated mucosa has only been evaluated in a limited way. The present study was undertaken to evaluate the expression of a target group of genes using RNA quantification assays and, more broadly, to assess patterns of mucosal gene expression using DNA microarray hybridization. Our results demonstrate the sequential upregulation of a series of genes that, when taken collectively, suggest an intricate functional interaction.