PCR primers for polymorphic microsatellite loci in the desert locust,Schistocerca gregaria (Orthoptera: Acrididae)

Nine pairs of polymerase chain reaction (PCR) primers that amplify polymorphic microsatellite loci in the desert locust, Schistocerca gregaria (Forskal), were developed using a magnetic bead‐based enrichment protocol. A sample of 48 locusts collected during the 1993 and 1995 upsurge periods in Eritrea, East Africa, were genotyped. The number of alleles per locus ranged from six to 20; the average was 12.67. Allelic distributions were significantly different between samples from different localities.     

Localization of Surface Structures During Procaryotic Differentiation: Role of Cell Division in Caulobacter crescentus

Asymmetric cell division in Caulobacter crescentus produces two cell types, a stalked cell and a new swarmer cell, with characteristics surface structures. We have examined the role of the cell cycle in the differentiation of these two cells using the adsorption of bacteriophage øLC72, the assembly of the polar flagellum, and stalk formation as assays for changes in surface morphology. Previous studies of this aquatic bacterium [17, 25] have suggested that the replicating chromosome acts as a 'clock' in timing the formation of the flagellar filament at one pole of the new swarmer cell. The analysis of conditional cell cycle mutants presented here extends these results by showing that DNA synthesis is also required for adsorption of phage øLC72 and, more importantly, they also suggest that a late cell division step is involved in determining the spatial pattern in which the phage receptors and flagella are assembled. We propose that this cell division step is required for formation of 'organizational' centers which direct the assembly of surface structures at the new cell poles, and for the polarity reversal in assembly that accompanies swarmer cell to stalked cell development.     

Growth and Nutrient Status of Quercus rubra L. in Response to Al and Ca

Northern red oak (Quercus rubra L.) seedlings were grown for63 d in a complete nutrient solution (pH 3.8) containing oneof three concentrations of Al (0, 0.75 or 2-0 mol m^–3)and either 10 or 250 mmol m^–3 Ca. Of all solution variables,the In of (Al³⁺)/(Ca²⁺), the solution activities ratio, wasmost closely correlated with declines in shoot and root growth.Ln (Al³⁺)/(Ca²⁺) also most closely predicted leaf and root [Mg],[Al], and [Al]/[Ca]. These three variables in turn were closelyrelated to growth. Toxic levels of (Al³⁺) and (Al³⁺)/(Ca²⁺)in solution are compared to levels in forest soils. Key words: Al phytotoxicity, Al x Ca interaction, Quercus rubra     

On the sipunculan genus Golfingia Lankester, 1885

The largest genus of the phylum Sipuncula is reviewed and a key provided to the six subgenera. Some historical comments are provided, particularly with reference to the recent monograph by Stephen & Edmonds (1972). It is noted, in concurrence with Gepner's (1965) views, that despite its large size, Golfingia is a natural unit and probably reflects the site of most rapid cladogenesis as well as being the most generalized, primitive genus. Ten species names (abnormis, cantabriensis, charcoti, derjugini, iniqua, kolense, pavlenkoi, profunda, pusilla, and sluiteri) are synonymized as well as one generic name (Nephasoma). The motivating force behind many of these changes was our consideration of species as populations rather than types. This work is based on the inspection of several type specimens as well as the authors' extensive experience with this genus.     

The Serine Hydroxymethyltransferase of Plasmodium lophurae*

SYNOPSIS. Plasmodium lophurae serine hydroxymethyltransferase (EC 2.1.2.1) was partially purified and characterized by (NH₄)₂SO₄ fractionation and chromatography on Sephadex G-100. The enzyme, precipitated by 3.0–3.3 m (NH₄)₂SO₄, had a molecular weight of 68,300 as estimated by exclusion chromatography on G-100. The pH optimum of the enzyme was 6.8–7.6 in sodium phosphate-citrate buffer. Citrate stabilized the enzyme during storage in phosphate buffer at 4 C. The K_m was 4.3 × 10^?3m for l -serine and 2.5 × 10^?4m for tetrahydrofolate.     

Maggot therapy: a review of the therapeutic applications of fly larvae in human medicine, especially for treating osteomyelitis

In traditional medical practice, the larvae of some Diptera: Calliphoridae, notably Lucilia illustris (Meigen), L.sericata (Meigen) and Phormia regina (Meigen), have been employed for maggot therapy, i.e. to help clean lesions antiseptically, especially for treatment of chronic osteomyelitis. This mode of treatment remains appropriate for cases where antibiotics are ineffective and surgery impracticable.     

A spatially explicit analysis to extrapolate carbon fluxes in upland tundra where permafrost is thawing

One of the most important changes in high‐latitude ecosystems in response to climatic warming may be the thawing of permafrost soil. In upland tundra, the thawing of ice‐rich permafrost can create localized surface subsidence called thermokarst, which may change the soil environment and influence ecosystem carbon release and uptake. We established an intermediate scale (a scale in between point chamber measurements and eddy covariance footprint) ecosystem carbon flux study in Alaskan tundra where permafrost thaw and thermokarst development had been occurring for several decades. The main goal of our study was to examine how dynamic ecosystem carbon fluxes [gross primary production (GPP), ecosystem respiration (R_eco), and net ecosystem exchange (NEE)] relate to ecosystem variables that incorporate the structural and edaphic changes that co‐occur with permafrost thaw and thermokarst development. We then examined how these measured ecosystem carbon fluxes responded to upscaling. For both spatially extensive measurements made intermittently during the peak growing season and intensive measurements made over the entire growing season, ecosystem variables including degree of surface subsidence, thaw depth, and aboveground biomass were selected in a mixed model selection procedure as the ‘best’ predictors of GPP, R_eco, and NEE. Variables left out of the model (often as a result of autocorrelation) included soil temperature, moisture, and normalized difference vegetation index. These results suggest that the structural changes (surface subsidence, thaw depth, aboveground biomass) that integrate multiple effects of permafrost thaw can be useful components of models used to estimate ecosystem carbon exchange across thermokarst affected landscapes.