Soft rot Erwinia bacteria in surface and underground waters in southern Scotland and in Colorado, United States

An anaerobic liquid enrichment method followed by plating on a selective medium revealed that the soft rot coliform bacterium Erwinia carotovora subsp. carotovora was generally present in water from drains, ditches, streams, rivers and lakes (including reservoirs) in southern Scotland and in Colorado, United States, in mountainous, upland and arable areas through the year. Many sites were remote from susceptible or diseased crops. Erwinia carotovora subsp. atroseptica was isolated much less frequently and no Erwinia bacteria were isolated from underground waters. Erwinia bacteria were also found in rain-water in Scotland, in winter snow from mountain passes in Colorado, and in sea water from the west and east coasts of Scotland and from the coasts of Oregon, California, Texas, Louisiana and Florida. The significance of the occurrence of these bacteria in water is discussed in relation to the control of blackleg and soft rot diseases of potato by production of Erwinia -free stocks.     

Photoperiodic induction of pupal diapause in the flesh fly,Sarcophaga crassipalpis: embryonic sensitivity

Summary The last two days of embryonic development are crucial in programming pupal diapause in the flesh fly,Sarcophaga crassipalpis. Short daylength (greater than 10 1/2h of darkness) during this interval permits expression of diapause while long daylength during this brief sensitive stage eliminates the potential for diapause. Length of scotophase rather than photophase programs the diapause although three hours of light is needed to separate tandem dark periods. Early in the scotophase, photosensitivity is restricted to blue light (less than 540 nm). The scotophase can be divided into 4 phases according to the effect of light breaks on diapause expression. During Phase I (0–6 h after scotophase onset) embryos are highly sensitive to light interruption and diapause is effectively eliminated. A period of insensitivity to light, Phase II, extends from 6–hh after onset of scotophase. Light breaks at 10–11h coincide with the critical scotophase length and result in a partial reduction of diapause. In Phase IV, the scotophase reaction is complete and diapause competence is preserved even in the presence of light. Although light breaks result in elimination of diapause throughout Phase I, recovery time from a 1 h light break (length of darkness needed to counter the effect of a light break) differs dramatically depending upon when the light break is presented. Early in Phase I (0–3h) recovery from light interruption is rapid, while late in Phase I (4–6h), the effects of light are not readily reversible. The scotophase reaction thus appears to follow a step-wise progression rather than represent a simple linear response. We present a molecular model that could account for the dynamics of the scotophase reaction.     

The transport of morphologically abnormal sperm in the female reproductive tract of mice

Mice of the PL/J strain exhibit a high percentage of morphologically abnormal sperm and provide a model for studying the function of abnormal sperm. The ability of such sperm to reach the site of fertilization within the female reproductive tract has been investigated. We have found a decrease in the percentage of structurally abnormal sperm within the population that reaches the oviduct. This observation suggests either that there is an active selection against abnormal sperm or that they are physiologically disadvantaged in reaching the site of fertilization.     

NALL-1, an acute lymphoblastic leukemia cell line with peroxidase activity

Summary All cells examined from the non-B, non-T acute lymphoblastic leukemia cell line, NALL-1, stained positive both for terminal deoxynucleotidyl transferase and for common ALL antigen. In addition, peroxidase activity was detected by light microscopy in 55 to 75% of cells and peroxidase-positive granules were detected ultrastructurally in >80% of cells. Peroxidase activity in NALL-1 may result from derepression of peroxidase genes or clonal proliferation of a biphenotypic precursor cell.     

Development of cerebellar astroglia: Transitions in form and cytoskeletal content

The forms, disposition, and cytoskeletal contents of astroglia in immature mouse cerebellum were studied by immunocytochemical staining with antisera against two intermediate filament proteins, vimentin (Vim) (58,000 daltons) and glial filament protein (GF) (51,000 daltons). From embryonic (E) Day 15 to postnatal (P) Day 2, Vim is expressed in cells throughout the cerebellar anlage, including radial glia and Bergmann fibers, cells with amorphous shapes and 2–3 processes, and thick longitudinal elements oriented parallel to axons within axon tracts. GF is not expressed during the first few postnatal days, but by P7, there is a dramatic increase in GF-positive astrocyte-like cells in the putative white matter that are more densely stained and more crowded than at any other age. Between P7 and P14 all astrocytes throughout the cerebellum express both Vim and GF. From P21 on, Vim expression is progressively rarer in all astrocytes except for Bergmann fibers, and GF-positive astrocytes become less numerous. These findings raise two issues: (a) the lineage and relationships of cells expressing Vim and GF; (b) Since GF-positive cells appear as axon ingrowth ceases, axons must grow in a terrain comprised of glial cells that have a different cytoskeletal composition (vimentin), reflecting a less differentiated state, than mature astrocytes or than the GF-rich astrocytes that proliferate after injury in adult CNS.     

The detection of picomolar quantities of GD1b,GT1b and GQ1b on thin-layer chromatograms by the direct binding of125I-labeled tetanus toxin,fragment C

The¹²⁵I-labeled fragment C of tetanus toxin was found to bind specifically to the gangliosides G_D1b, G_T1b, and G_Q1b when applied to thin-layer chromatograms on which a mixture of gangliosides had been resolved. As little as 2.5 pmoles of these gangliosides could be detected by this method. In addition to factors determined by the sample, namely the amount and species of gangliosides present, optimal binding of the¹²⁵I-labeled fragment C also depended upon the iodination procedure used to generate the probe, the toxin concentration, and the concentration, buffer type, pH, and ionic strength of the binding solution. This new technique was shown to be a sensitive method for the detection and identification of specific gangliosides originating from extraneural or neural cells.Nomenclature: The gangliosides follow the nomenclature system of Svennerholm [Eur J Biochem (1977) 79:11–21] G_M3 II³NeuAc-LacCer - G_D3 II³(NeuAc)₂-LacCer - G_M1 II³NeuAc-GgOse₄Cer - G_D1a IV³NeuAc, II³NeuAc-GgOse₄Cer - G_D1b II³(NeuAc)₂-GgOse₄Cer - G_T1b IV³NeuAc, II³(NeuAc)²-GgOse₄Cer - G_Q1b IV³(Neu-Ac)₂, II³(NeuAc)₂-GgOse₄Cer - G_P1b IV³(NeuAc)₃, II³(NeuAc)₂-GgOse₄Cer     

The uptake of soil and fertilizer-nitrogen by barley growing under Scottish climatic conditions

Summary Field experiments were carried out using¹⁵N-labelled calcium nitrate, to investigate the relative uptake by barley of fertilizer-N and soil-N. On imperfectly drained till soils uptake of soil-N increased with increasing rate of fertilizer, but remained constant on a brown sand, possibly due to more efficient root exploration in the latter soil. In four out of five seasons, late uptake of soil-derived N was a major feature, and uptake from ploughed soil as compared with uptake from direct-drilled soil was correlated with seasonal rainfall patterns. Significantly higher quantities of both fertilizer- and soil-derived N were taken up by winter barley than by spring barley, reflecting the longer growth period and higher dry matter yield from the former crop.