Eimeria zapi sp. n. from the Meadow Jumping Mouse, Zapus hudsonius Zimmerman in Southwestern Michigan

SYNOPSIS Four of 5 meadow jumping mice ( Zapus hudsonius ) captured had in their feces a previously undescribed species of Eimeria which is named Eimeria zapi sp. n. The sporulated oocysts measured 21.7 (19.5–24.0) × 20.3 (17.5–23.0) μm. The single-layered oocyst wall was 1.5 μm thick, rough, pitted and appeared clear-to-amber. Usually 2 polar granules could be seen. An oocyst residuum was not observed. Each sporocyst averaged 16.0 (12.5–18.0) × 9.7 (7.5–11.5) μm. A substiedal body was present. The sporocyst residuum consisted of a membrane-enclosed packet of 15 to 20 granules. This is the first species of Eimeria to be described from the genus Zapus.     

Mobilization of metals from uranium mine waste: the role of pyoverdines produced by Pseudomonas fluorescens

Microorganisms produce chelating agents, such as siderophores and other ligands, which allow them to mobilize and scavenge essential elements from the environment when bioavailability is low. To better understand the effects of biologically mediated leaching of metals from mine waste, Pseudomonas fluorescens was cultivated in the presence of processed ore from the former uranium mine in Ranstad, southern Sweden. Light conditions, the concentration of the mineral source and oxygen availability were varied. The presence of ore in the culture flasks enhanced bacterial growth and raised the pH of the culture medium. Increasing the amount of ore or enhancing aeration of the medium further encouraged cell growth and pH rise. Bacteria mobilized Fe, Ni and Co from the ore. Fe‐siderophore complexes were detected and estimated to be present at approximately 9 μm . In the presence of bacteria and light, dissolved Fe and U concentrations were higher compared to dark conditions. Increasing the amount of ore resulted in higher dissolved Ni concentrations but lower dissolved Fe, most likely due to precipitate formation. Data from this study support siderophore production by bacteria that allowed mobilization of essential nutrients from the processed ore. However, the availability of potentially toxic metals like Ni and U may also be enhanced. Microbial‐promoted mobilization could contribute to leaching of toxic metals in current and historic mining areas. This process should be considered during design and implementation of remediation projects where trace metals are of environmental concern.     

What future for British red squirrels?

The geographic range of red squirrels contracted sharply in Britain during the 1940s arid 1950s, as increasingly large areas were colonized by the congeneric North American grey squirrel. Red squirrels remain common only on offshore islands, and in the large conifer forests of northern England and Scotland. The initial replacement of red squirrels was in arras dominated by oak woodland, probably because acorn crops are exploited less efficiently by red squirrels than by grey squirrels. Dirt studies have shown that acorns are digested less efficiently by the red squirrel, which occurs in conifers through most of its Eurasian range, than by the introduced grey squirrel, which is primarily a native of deciduous woodland. The red squirrel will probably be replaced in deciduous and mixed woodland throughout mainland Britain, and may eventually persist only in large areas of conifers which arc far from oak trees. The conservation of red squirrels on islands is therefore particularly important for their survival, perhaps making it worthwhile to create new island populations where they do not at present exist.     

Inhibition of Deoxyribonuclease Activity in Synchronized Tetrahymena

SYNOPSIS. Deoxyribonuclease (DNase) activity in crude homogenates of synchronized cultures of Tetrahymena pyriformis GL was inhibited by added acidic polymers (which inactivated the enzyme) and polyamines (which blocked enzyme sites on the substrate). The inhibition appeared to be a nonspecific reaction between basic groups on the enzyme and acidic groups on the substrate. The relation between variation in DNase activity and amount of DNA was analyzed by means of puromycin and mitomycin C. DNase activity was lower after addition of each antibiotic, without significant change in amount of DNA. The results suggest that induction of DNase synthesis is governed by the amount of DNA.     

No inhibitory effect on receptor neurone activity by sulphur analogues of the sex pheromone component (Z)-5-decenyl acetate in the turnip moth, Agrofis segetum (Lepidoptera: Noctuidae)

Abstract. Olfactory responses from the entire antenna and from single antennal sensilla of the male turnip moth, Agrotis segetum (Lepidoptea: Noctuidae Schiff.), were recorded after stimulation of the antenna with the sex pheromone component, (Z)-5-decenyl acetate (Z5-10:OAc), and three sulphur analogues of this compound. Adaptation of olfactory receptor neurones tuned to Z5-10:OAc was investigated after pre-exposure of these receptor neurones to the key stimulus and to the three sulphur analogues. Both electro-antennographic and single sensillum recordings revealed that the sulphur analogues had a significantly decreased effect compared to the natural stimulus. The pre-exposure experiments demonstrated that no further inhibition of neural activity was observed than could be expected from receptor neurone adaptation. Earlier reports, describing sulphur analogues as possible hyperagonists acting on moth pheromone receptor neurones, are not supported by the present study.     

Comparison of male and female olfactory cell response to pheromone compounds and plant volatiles in the turnip moth, Agrotis segetum

ABSTRACT. Pheromone and plant volatile perception was studied with electroantennogram and single sensillum techniques in male and female turnip moths, Agrotis segetum Schiff. Lepidoptera, Noctuidae. The female is insensitive to the pheromone components and her receptors are specialized for plant volatile reception. The specific pheromone receptors on the male antenna are also sensitive to plant volatiles. The male was in addition found to have specialized plant volatile receptors. The biological significance of the different response profiles in males and females, and a possible hypothesis for the evolutionary specialization of olfactory receptors are discussed.