Effects of Local Conspecific Density on Reproductive Success in Penstemon Digitalis and Hesperis Matronalis

Author Institution: Department of Biology, University of AkronWe investigated the effects of plant density on reproductive success for two insect-pollinated plant species—the native North American wildflower Penstemon digitalis (Foxglove-leaved Penstemon), and the showy introduced weed Hesperis matronalis (Dame's Rocket). We found no indication that local density (within 3.0 m) affected reproductive success (seeds per fruit, proportion fruit set, total seeds per plant) for either species. Penstemon digitalis suffered heavy fruit predation from micro-lepidopterans, and such damage tended non-significantly to increase with density. We discuss the reasons for our results, and suggest that an understanding of those causes is important for conservation

B cells produce pathogenic antibodies and impair recovery after spinal cord injury in mice

Traumatic injury to the mammalian spinal cord activates B cells, which culminates in the synthesis of autoantibodies. The functional significance of this immune response is unclear. Here, we show that locomotor recovery was improved and lesion pathology was reduced after spinal cord injury (SCI) in mice lacking B cells. After SCI, antibody-secreting B cells and Igs were present in the cerebrospinal fluid and/or injured spinal cord of WT mice but not mice lacking B cells. In mice with normal B cell function, large deposits of antibody and complement component 1q (C1q) accumulated at sites of axon pathology and demyelination. Antibodies produced after SCI caused pathology, in part by activating intraspinal complement and cells bearing Fc receptors. These data indicate that B cells, through the production of antibodies, affect pathology in SCI. One or more components of this pathologic immune response could be considered as novel therapeutic targets for minimizing tissue injury and/or promoting repair after SCI

An efficient and reproducible method for quantifying macrophages in different experimental models of central nervous system pathology

Historically, microglia/macrophages are quantified in the pathological central nervous system (CNS) by counting cell profiles then expressing the data as cells/mm(2). However, because it is difficult to visualize individual cells in dense clusters and in most cases it is unimportant to know the absolute number of macrophages within lesioned tissue, alternative methods may be more efficient for quantifying the magnitude of the macrophage response in the context of different experimental variables (e.g., therapeutic intervention or time post-injury/infection). The present study provides the first in-depth comparison of different techniques commonly used to quantify microglial/macrophage reactions in the pathological spinal cord. Individuals from the same and different laboratories applied techniques of digital image analysis (DIA), standard cell profile counting and a computer-assisted cell counting method with unbiased sampling to quantify macrophages in focal inflammatory lesions, disseminated lesions caused by autoimmune inflammation or at sites of spinal trauma. Our goal was to find a simple, rapid and sensitive method with minimal variability between trials and users. DIA was consistently the least variable and most time-efficient method for assessing the magnitude of macrophage responses across lesions and between users. When used to evaluate the efficacy of an anti-inflammatory treatment, DIA was 5-35x faster than cell counting and was sensitive enough to detect group differences while eliminating inter-user variability. Since lesions are clearly defined and single profiles of microglia/macrophages are difficult to discern in most pathological specimens of brain or spinal cord, DIA offers significant advantages over other techniques for quantifying activated macrophages. (C) 2009 Elsevier B.V. All rights reserve