Thermographic visualization of cell death in tobacco and Arabidopsis

Pending cell death was visualized by thermographic imaging in bacterio‐opsin transgenic tobacco plants. Cell death in these plants was characterized by a complex lesion phenotype. Isolated cell death lesions were preceded by a colocalized thermal effect, as previously observed at sites infected by tobacco mosaic virus (TMV) ( Chaerle et al. 1999 Nature Biotechnology 17, 813–816). However, in most cases, a coherent front of higher temperature, trailed by cell death, initiated at the leaf base and expanded over the leaf lamina. In contrast to the homogenous thermal front, cell death was first visible close to the veins, and subsequently appeared as discrete spots on the interveinal tissue, as cell death spread along the veins. Regions with visible cell death had a lower temperature because of water evaporation from damaged cells. In analogy with previous observations on the localized tobacco–TMV interaction ( Chaerle et al. 1999 ), the kinetics of thermographic and continuous gas exchange measurements indicated that stomatal closure preceded tissue collapse. Localized spontaneous cell death could also be presymptomatically visualized in the Arabidopsis lsd2 mutant.     

Isolation by affinity chromatography of a cholinergic proteolipid from Nucleus caudatus.

A cholinergic proteolipid fraction (i.e. a hydrophobic lipoprotein) was separated from the $\text{n. caudatus}$ of the cow, using affinity chromatography with the lipophilic gel Sephadex LH-20 and p-phenyltrimethylamonium as the active group. High affinity binding studies showed that only the specific fraction, desorbed after an acetylcholine (or acid) pulse, and corresponding to 0,72% of the proteolipids, is the one that binds the cholinergic ligands. The binding of (³H)atropine and (¹⁴C)d-tubocurarine demonstrated that there are 814 picomoles/g fresh tissue of muscarinic sites and only 76 picomoles/g of nicotinic sites. The specific radioactivity for (³H)atropine is 10,000 nmoles/g protein, suggesting a high degree of purification of the specific cholinergic proteolipid.     

UDP-Gal: <Emphasis Type="Italic">N</Emphasis>-acetylglucosamine β 1–4 galactosyltransferase expressing live attenuated parasites as vaccine for visceral leishmaniasis

As compared to cutaneous leishmaniasis, vaccination against visceral leishmaniasis (VL) has received limited attention. In this study, we demonstrate for the first time that an UDP-Galactose: N-acetylglucosamine β 1–4 galactosyltransferase (GenBank Accession No. EF159943) expressing attenuated LD clonal population (A-LD) is able to confer protection against the experimental challenge with the virulent LD AG83 parasite. A-LD was also effective in established leishmania infection. The vaccinated animals showed both cell mediated (in vitro T-cell proliferation, and DTH response) and humoral responses (Th1 type). These results demonstrate the potential of the attenuated clones as an immunotherapeutic and immunoprophylactic agent against visceral leishmaniasis.     

Linkage analysis of the murine mos proto-oncogene on chromosome 4

A linkage analysis of the murine Mos gene, which codes for the c-mos proto-oncogene, was performed in 88 backcross progeny of an interspecies cross of laboratory mice and Mus spretus. Linkage was tested for four different genes on mouse chromosome 4: Aco-1, Mup-1, b, and Ifb. The gene order (from centromere) with intervening percentage recombination is Mos-15.9 (+/- 3.9)-Aco-1-5.6 (+/- 2.4)-Mup-1-3.4 (+/- 1.9)-b-5.6 (+/- 2.4)-Ifb. These results confirm the previous assignment of Mos to chromosome 4 on the basis of segregation in somatic cell hybrids (D. Swan et al., 1982, J. Virol. 44: 752-754) and show furthermore that Mos and the Ifa/Ifb clusters are not tightly linked as a group of intronless genes, but are separated by a map distance of 30.6 +/- 4.9 recombination units. The linkage data obtained in the present study place Mos in a region compatible with the physical map (D. W. Threadgill and J. E. Womack, 1988, Genomics 3: 82-86).     

Linkages between seagrass,mangrove and saltmarsh as fish habitat in the Botany Bay estuary,New South Wales

Shallow-water vegetated estuarine habitats, notably seagrass, mangrove and saltmarsh, are known to be important habitats for many species of small or juvenile fish in temperate Australia. However, the movement of fish between these habitats is poorly understood, and yet critical to the management of the estuarine fisheries resource. We installed a series of buoyant pop nets in adjacent stands of seagrass, mangrove and saltmarsh in order to determine how relative abundance of fishes varied through lunar cycles. Nets were released in all habitats at the peak of the monthly spring tide for 12 months, and in the seagrass habitat at the peak of the neap tide also. The assemblage of fish in each habitat differed during the spring tides. The seagrass assemblage differed between spring and neap tide, with the neap tide assemblage showing greater abundances of fish, particularly those species which visited the adjacent habitats when inundated during spring tides. The result supports the hypothesis that fish move from the seagrass to the adjacent mangrove and saltmarsh during spring tides, taking advantage of high abundances of zooplankton, and use seagrass as a refuge during lower tides. The restoration and preservation of mangrove and saltmarsh utility as fish habitat may in some situations be linked to the proximity of available seagrass.