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.     

Measurements of cytoplasmic and vacuolar pH in Neurospora using nitrogen-15 nuclear magnetic resonance spectroscopy

The nitrogen-15 chemical shift of the N1 (tau)-nitrogen of 15N-labeled histidine and the half-height line widths of proton-coupled resonances of the delta- and omega,omega'-nitrogens of 15N-labeled arginine and of the alpha-nitrogens of 15N-labeled alanine and proline were measured in intact mycelia of Neurospora crassa to obtain to estimates of intracellular pH. For intracellular 15N-labeled histidine, the N1 (tau)-nitrogen chemical shift was 200.2 ppm. In vitro measurements showed that the chemical shift was slightly affected by the presence of phosphate, with which the basic amino acids may be associated in vivo. These considerations indicate a pH of 5.7-6.0 for the environment of intracellular histidine. The half-height line widths of the delta- and omega,omega'-nitrogens of [15N]arginine were 15 and 26 Hz, respectively. In vitro studies showed that these line widths also are influenced by the presence of phosphate, and, after suitable allowance for this, the line widths indicate pH 6.1-6.5 for intracellular arginine. The half-height line widths for intracellular alanine and proline were 17 and 12 Hz, respectively, which are consistent with an intracellular pH of 7.1-7.2. Pools of histidine and arginine are found principally in the vacuole of Neurospora, most likely in association with polyphosphates. Proline and alanine are cytoplasmic. The results reported here are consistent with these localizations and indicate that the vacuolar pH is 6.1 +/- 0.4 while the cytoplasmic pH is 7.15 +/- 0.10. Comparisons of these estimates with those obtained by other techniques and their implications for vacuolar function are discussed.     

Carbamoyl-phosphate synthetases from Neurospora crassa. Immunological relatedness of the enzymes from Neurospora, bacteria, yeast, and mammals

Neurospora crassa contains two carbamoyl-phosphate synthetases: a mitochondrial enzyme (CPS-A) which supplies carbamoyl phosphate for arginine biosynthesis, and a nuclear enzyme whose product is used for the synthesis of pyrimidines. We have prepared antiserum against a highly purified preparation of the large subunit of CPS-A and have used the antiserum to demonstrate that the large subunit is, like most mitochondrially localized proteins, initially synthesized as a higher molecular weight precursor. The CPS-A antiserum cross-reacts with the nuclear enzyme, allowing us to identify the product of the complex N. crassa pyr-3 genetic locus as a protein with a subunit molecular weight of 180,000. Finally, we have found that the CPS-A antiserum also cross-reacts with carbamoyl-phosphate synthetases from bacteria, yeast, and mammals. The immunological relatedness of carbamoyl-phosphate synthetases from such diverse species suggests that the protein sequences required for carbamoyl phosphate production have been highly conserved during the course of evolution.     

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.     

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.