Effects of long-term fixation on histological quality of undecalcified murine bones embedded in methylmethacrylate

While long-term fixation and storage of specimens is common and useful for many research projects, it is particularly important for space flight investigations where samples may not be returned to Earth for several months (International Space Station) or years (manned mission to Mars). We examined two critical challenges of space flight experimentation: the effect of long-term fixation on the quality of mouse bone preservation and the preservation of antigens and enzymes for both histochemical and immunohistochemical analyses, and how the animal/sample processing affects the preservation. We show that long-term fixation minimally affects standard histological staining, but that enzyme histochemistry and immunolabeling are greatly compromised. Further, we demonstrate that whole animal preservation is not as suitable as whole leg or stripped leg preservation for long-term fixation and all histological analyses. Overall, we recommend whole leg processing for long-term storage of bone specimens in fixative prior to embedding in plastic for histological examination.     

The conservation of the belted beauty Lycia zonaria britannica (Lepidoptera, Geometridae) in the United Kingdom

Recent surveys have established that the belted beauty moth Lycia zonaria britannica, which is an endemic subspecies found only in the British Isles, now occurs at just three sites in England and Wales. Populations at all three sites are small, with annual peak counts of usually less than 50 females. At Morfa Conwy in Wales and Meols Common in England, habitat quality has been declining for more than a decade as open, herb-rich, early successional dune grassland is replaced by fixed, rank grassland. Uniquely at Sunderland Point in England, the moth is primarily associated with areas of saltmarsh, but distribution is constrained by surrounding farmland and man-made structures. Attempts are now being made to restore areas of open grassland and to return the moth to its former distribution. Since the winter of 2000-2001, small plots of rank grassland on Meols Common have been excavated annually, with all vegetation removed, together with any humic layer present. The exposed bare sand has then been allowed to re-vegetate naturally. Within 18 months, the plots have developed into open, herb-rich habitats suitable for the moth. Adults were recorded on the plots for the first time in spring 2003 and may have been the product of the small numbers of eggs and larvae introduced to the plots in spring 2002. Similar excavations have been initiated at Morfa Conwy, which is in the process of being notified as a Site of Special Scientific Interest (SSSI). A 3-year programme to establish a second Welsh population is underway and, to date, more than 2000 captive-reared larvae have been released on the receptor site which lies 21 km to the east of Morfa Conwy.     

Inhibition of PKA Blocks Fibroblast Migration in Response to Growth Factors

Cell migration requires precise coordination of many signaling pathways to achieve directed motility. We report here that NIH3T3 fibroblasts expressing a dominant negative PKA subunit (dnPKA) show diminished migration in response to serum or growth factors. This effect is not a general effect on cell motility, but rather a decreased capacity to enhance migration in response to stimuli. Control (neo) and dnPKA cells show very similar haptotactic migration toward fibronectin, but dnPKA cells show reduced stimulation of migration in response to EGF/PDGF or serum. These effects were not due to alterations in cell growth or adhesion to fibronectin. Forskolin, which elevates cyclic adenosine monophosphate (cAMP) levels, dramatically inhibited neo cell motility in a scrape migration assay, although dnPKA cell migration was unaffected. The MEK selective inhibitor U0126 and the phosphatidyl-inositol-3 kinase (PI3K) inhibitor LY294002 inhibited migrating neo cells and were able to further inhibit residual dnPKA cell migration. Our data show that intermediate or well-controlled levels of PKA activity are required for optimal growth factor-stimulated migration in fibroblasts. PKA may play an important role in the signaling processes that lead to motility.     

Female choice linked to male dorsal fin height in a shortfin molly

Sexual selection is a possible mechanism of speciation. This could be true even in systems where female mate choice has not been clearly observed, because pre-existing biases may be expressed if female decision-making results in male trait evolution. In some mollies, males have enlarged dorsal fins and courtship display is the prevailing mating process. In others, male dominance is thought to play a greater role. We tested females of a species in the latter group, Poecilia mexicana, for consistent preference related to dorsal fin morphology. We found that females were biased toward larger dorsal fins. This latent preference could be an important driver in trait evolution.