Ichthyophthirius multifiliis (Fouquet) in the mirror carp, Cyprinus carpio L.

Mirror carp were infected with Ichthyophthirius multifiliis (Fouquet) under standardized conditions. The size and number of parasites at selected sites on the body were recorded during the course of the infection. Initial exposure to 40 mature parasites resulted in a mild infection with 100% recovery after 18 days. Recovered fish did not appear to be carriers of the parasite. Exposure to 400 parasites resulted in 100% mortality between 22–25 days. The growth rate of the parasite was linear. Parasites were more numerous in the dorsal surface of the fish than in the lateral or ventral surface. The increase in parasite numbers during the disease was greater in the gills than in the skin.     

Elemental Fingerprinting of Mussel Shells to Predict Population Sources and Redistribution Potential in the Gulf of Maine

As the climate warms, species that cannot tolerate changing conditions will only persist if they undergo range shifts. Redistribution ability may be particularly variable for benthic marine species that disperse as pelagic larvae in ocean currents. The blue mussel, Mytilus edulis, has recently experienced a warming-related range contraction in the southeastern USA and may face limitations to northward range shifts within the Gulf of Maine where dominant coastal currents flow southward. Thus, blue mussels might be especially vulnerable to warming, and understanding dispersal patterns is crucial given the species'' relatively long planktonic larval period (>1 month). To determine whether trace elemental “fingerprints” incorporated in mussel shells could be used to identify population sources (i.e. collection locations), we assessed the geographic variation in shell chemistry of blue mussels collected from seven populations between Cape Cod, Massachusetts and northern Maine. Across this ∼500 km of coastline, we were able to successfully predict population sources for over two-thirds of juvenile individuals, with almost 80% of juveniles classified within one site of their collection location and 97% correctly classified to region. These results indicate that significant differences in elemental signatures of mussel shells exist between open-coast sites separated by ∼50 km throughout the Gulf of Maine. Our findings suggest that elemental “fingerprinting” is a promising approach for predicting redistribution potential of the blue mussel, an ecologically and economically important species in the region.     

Terpenoid and morphological variability of Pinus quadrifolia and the natural hybridization with Pinus monophylla in the San Jacinto Mountains in California

Monoterpenoids from wood of Pinus quadrifolia and Pinus monophylla from south of the San Jacinto Mountains in southern California were analysed by gas-liquid chromatography (GLC). The number of needles per fascicle, the number of resin canals, and the number of abaxial and adaxial stomatal rows in the needles were determined. Percentages of mycrene, α-pinene, and to a minor extent of camphene, β-pinene, limonene, and β-phellandrene, the above mentioned morphological characteristics and previously obtained data were all used for identification and characterisation of species intermediacy in the San Jacinto area. It was concluded that many P. quadrifolia trees in the mixed Buck Ridge stand and some trees in two pure stands of the same area were hybrids and that sympatric and to a lesser extent allopatric introgression of P. monophylla into P. quadrifolia takes place in the San Jacinto region. Introgression of P. quadrifolia into P. monophylla could not be demonstrated.     

Lipid microdomains and membrane trafficking in mammalian cells

This overview summarizes the data for how epithelial cells sort and deliver proteins and lipids to the apical and basolateral cell surface domains. The basolateral pathway uses a Rab-SNARE mechanism for docking and fusion, while the apical route employs a different machinery. This latter mechanism is based on lipid microdomains, composed of clusters of sphingolipids and cholesterol, which function as rafts for apical delivery. The sphingolipid-cholesterol raft mechanism seems to be employed generally by mammalian cells to transport raft-associated proteins to their post-Golgi destinations.     

Glucocorticoid receptor binding to calf thymus DNA. 1. Identification and characterization of a macromolecular factor involved in receptor-steroid complex binding to DNA.

Activation of receptor-steroid complexes to a form with high affinity for DNA is a poorly understood process involving multiple components in addition to the holoreceptor. Employing rat HTC cells as the source of glucocorticoid receptor, we show that maximal receptor binding to calf thymus DNA is mediated by a previously unknown small molecular weight factor. This factor can be removed from cytosolic preparations of receptor by gel filtration chromatography. Salt extraction of crude nuclear pellets afforded much larger amounts of a similar DNA-binding activity factor. The cytoplasmic factor and the more abundant nuclear factor were identical on the basis of their similar physical properties. The factor was precipitable in the crude state with (NH4)2SO4 and stable to heat as well as freezing and thawing. Chromatography on DNA-cellulose revealed that the factor itself did not bind to DNA. The factor could be filtered through a Centricon C-3 microconcentrator (molecular weight cutoff approximately 3000) but was excluded from Sephadex G-10 columns. These parameters enable us to determine an apparent molecular weight of 700-3000 for this factor. The presence of large amounts of this factor in nuclei accounts for the previously unexplained observation that, following size exclusion chromatography, more activated complexes bind to nuclei than to DNA. These data indicate that some, but not all, of the activated complexes require factor to be able to bind to DNA. The predominantly nuclear localization of this factor, coupled with its ability to increase DNA binding, attests to the biological relevance of this factor in the whole cell action of receptor-glucocorticoid complexes.     

Isomeric lipid signatures reveal compartmentalized fatty acid metabolism in cancer

The cellular energy and biomass demands of cancer drive a complex dynamic between uptake of extracellular FAs and their de novo synthesis. Given that oxidation of de novo synthesized FAs for energy would result in net-energy loss, there is an implication that FAs from these two sources must have distinct metabolic fates; however, hitherto, all FAs have been considered part of a common pool. To probe potential metabolic partitioning of cellular FAs, cancer cells were supplemented with stable isotope-labeled FAs. Structural analysis of the resulting glycerophospholipids revealed that labeled FAs from uptake were largely incorporated to canonical (sn-) positions on the glycerol backbone. Surprisingly, labeled FA uptake also disrupted canonical isomer patterns of the unlabeled lipidome and induced repartitioning of n-3 and n-6 PUFAs into glycerophospholipid classes. These structural changes support the existence of differences in the metabolic fates of FAs derived from uptake or de novo sources and demonstrate unique signaling and remodeling behaviors usually hidden from conventional lipidomics.     

Reconstitution of the fusogenic activity of vesicular stomatitis virus.

Enveloped virus glycoproteins exhibit membrane fusion activity. We have analysed whether the G protein of vesicular stomatitis virus, reconstituted into liposomes, is able to fuse nucleated cells in a pH-dependent fashion. Proteoliposomes produced by octylglucoside dialysis did not exhibit cell fusion activity of the G protein. However, by making use of n-dodecyl octaethylene monoether (C12E8) as the solubilizing agent and by removal of the detergent in two steps, we were able to produce fusogenic G protein liposomes. These G protein liposomes fuse to the BHK-21 cell surface at pH 5.7-6.0 with an efficiency of fusion comparable with that of the parent virus. Physical and chemical analysis revealed that the fusogenic liposomes exhibited a protein to lipid weight ratio of 0.67 and showed an average diameter of 130 nm.