Blueberry flavonoids inhibit matrix metalloproteinase activity in DU145 human prostate cancer cells.

Regulation of the matrix metalloproteinases (MMPs), the major mediators of extracellular matrix (ECM) degradation, is crucial to regulate ECM proteolysis, which is important in metastasis. This study examined the effects of 3 flavonoid-enriched fractions (a crude fraction, an anthocyanin-enriched fraction, and a proanthocyanidin-enriched fraction), which were prepared from lowbush blueberries (Vaccinium angustifolium), on MMP activity in DU145 human prostate cancer cells in vitro. Using gelatin gel electrophoresis, MMP activity was evaluated from cells after 24-hr exposure to blueberry fractions. All fractions elicited an ability to decrease the activity of MMP-2 and MMP-9. Of the fractions tested, the proanthocyanidin-enriched fraction was found to be the most effective at inhibiting MMP activity in these cells. No induction of either necrotic or apoptotic cell death was noted in these cells in response to treatment with the blueberry fractions. These findings indicate that flavonoids from blueberry possess the ability to effectively decrease MMP activity, which may decrease overall ECM degradation. This ability may be important in controlling tumor metastasis formation.     

Isolation of Actinobacillus suis from a Canada goose (Branta canadensis)

Blindness from conjunctivitis caused by Actinobacillus suis was found in a Canada goose (Branta canadensis) from a wildlife refuge in Kentucky. Lesions were not observed elsewhere and other body organs were grossly normal. Actinobacillus spp. in birds is rare and this is apparently the first report of conjunctivitis resulting from this infection in waterfowl.     

Additive and independent responses in a single receptor: aspartate and maltose stimuli on the tar protein

The aspartate and maltose responses of E. coli are mediated through a single membrane receptor, yet the responses are independent and additive. Both stimuli cause methylation of the same 4 glutamic acid residues. More extensive methylation occurs when a cell that has adapted to one stimulus is exposed to the second, or when both stimuli are added simultaneously. The degree of methylation, as well as receptor migration on two-dimensional gels, demonstrates that only one type of protein is involved, rather than two different receptors arising from differential processing of a single gene. A conformational "push-pull" mechanism in which binding of stimulus and covalent modification, producing opposing stresses, can explain these diverse results.     

Vaginal treatment with a prostaglandin F2 alpha derivative (alfaprostol) for inducing labor in pregnancy at term

The effectiveness and acceptability of Alfaprostol (an analog of PGF2 alpha) in inducing labor were assessed in 20 pregnant women at term. All subjects had no spontaneous uterine activity before treatment and the mean (M +/- SE) Bishop score was 2.45 +/- 0.21. The drug was administered by vaginal route at the dose of 10 mg every 3 hours. Regular uterine contractions appeared in all patients and delivery occurred in 85% of the patients after a mean time of 9h50min +/- 0h55min following the start of treatment. The mean dose of Alfaprostol utilized to achieve delivery was 29.4 +/- 2.0 mg. No major side effects were noted in the mothers and their fetuses at any time during treatment. Two patients exhibited vomiting. The Apgar score of all newborns at birth was 8 or more. These results suggest the usefulness of Alfaprostol to induce labor in pregnant women at term, as it has oxytocic activity without adverse effects on either the mother or the fetus.     

The effect of Ca2+ on the thermal stability of trypsin in phosphate-buffered saline solution used for harvesting of human embryonic lung fibroblast cultures

The stabilizing effect of Ca2+ (264.9 mg CaCl2 X 2H2O ml-1) on a 0.5% solution of twice-crystallized bovine trypsin in phosphate-buffered saline (used for harvesting human embryonic lung fibroblasts) was studied at 7-37 degrees C and at -20 and -70 degrees C. It can be concluded that storage of the enzyme in the buffer (with or without Ca2+) is not advisable at temperatures greater than or equal to 20 degrees C. At 7 degrees C, on the other hand, trypsin can be stored for some weeks in the calcium-containing phosphate-buffered saline if a moderate loss of activity is acceptable. At -20 degrees C and -70 degrees C the stability of the enzyme was good. In the presence of Ca2+ about 90% of the activity remained after 18 weeks. Without Ca2+ the activity was approximately 10% lower.     

Microzooplankton and macrozooplankton glutamate dehydrogenase as indices of the relative contribution of these fractions to ammonium regeneration in the Gulf of Maine

Ammonium regeneration by micro- (35–153 µm) andmacrozooplankton (> 153 µm) was determined in the Gulfof Maine by measuring the activity of the excretory enzyme glutamatedehydrogenase (GDH) in various size fractions. GDH maxima weregenerally observed to correspond to the depth of the chlorophyllmaximum as previously reported in the Gulf of Mexico and inthe vicinity of the Nantucket Shoals. GDH activity of the microzooplanktonwas considerably lower than the macrazooplankton, suggestingthe microzooplankton made only a minor contribution (1–11%) to the total ammonium regenerated. These results were confirmedby biomass estimates made from counts of individual species.Ammonium excretion by both zooplankton fractions was estimatedto supply 5–31 % of the nitrogen requirements for primaryproduction, with an estimated 59–63% supplied by the verticaltransport of nitrate (new nitrogen) into the euphoric zone.     

Structure of a protein catalyzing the formation of 11 cis-retinal in the visual cycle of invertebrate eyes

A pigment made up of a protein able to bind retinal as well as retinol is described. The molecule consists of a dimer with a molecular weight of 50,000 which binds one molecule of retinal. The binding site for retinal is a Schiff base buried in the interior of the protein. Retinol is probably bound to the protein in the same site as for retinal, although not covalently, as suggested by the absorbance spectra. The protein, extracted from honeybee retina, is involved in visual pigment metabolism, and its structure may elucidate the mechanism of the stereospecific photoisomerization of all trans-retinal to 11-cis-retinal.     

Pheophytin-mediated energy storage of photosystem II particles detected by photoacoustic spectroscopy

The photoacoustic (PA) characteristics (energy storage and heat dissipation) of photosystem II (PSII) core-enriched particles from barley were studied (i) in conditions where there was electron flow, i.e., in the presence of a combination of the electron acceptor K₃ Fe (CN)₆, referred to as FeCN, and the electron donor diphenylcarbazide (DPC), and (ii) in conditions where electron flow was suppressed, i.e., in the absence of FeCN and DPC. The experimental data show that a decrease of heat dissipation with a minimum at 540 nm can be interpreted as energy storage resulting from the presence of pheophytin (Pheo) in the PSII particles. On account of the capability of the PA method to measure the energy absorbed by the chromophores which is converted to heat, it is suggested that the PA detection of Pheo present in the PSII complex will permit to clarify the function of processes involving non-radiative relaxation of excited states in P680-Pheo-Q_A interactions.Abbreviations -Car -Carotene - Chl Chlorophyll - DPC Diphenylcarbazide - EPR Electron Paramagnetic Resonance - FeCN potassium ferricyanide - HEPES N-2-hydroxyethylenepiperazine-N-2-ethanesulfonate - P680 reaction center of PSII - PA Photoacoustic - Pheo pheophytin - PSI photosystem I - PSII photosystem II - Q_A primary electron acceptor of PSII     

Transforming potential of a myc-containing variant of feline leukemia virus in vitro in early-passage feline cells.

We studied a naturally occurring variant of feline leukemia virus (FeLV) in which the oncogene myc has substituted for a portion of the viral structural genes (myc-FeLV). myc-FeLV was rescued by replication in the presence of FeLV as helper, and its biological activity was examined in early-passage feline cells in vitro. Infection of leukocytes from peripheral blood, spleen, or thymus, or of kitten fibroblasts did not immortalize these cells or alter them morphologically. Northern blot (RNA blot) analysis of virion RNA prepared from the supernatant of infected cells demonstrated the 8.2-kilobase genome of FeLV, but did not demonstrate the 5.0-kilobase genome of myc-FeLV. Apparently, the myc-FeLV genome was lost in the absence of the selective pressure of transformation. In contrast, infection of embryonic fibroblasts with myc-FeLV(FeLV) rendered these cells capable of greatly increased, if not infinite, proliferative potential. The cells were morphologically altered compared with controls and were only loosely adherent to the substrate. The cells failed to proliferate in semisolid medium and did not form tumors when inoculated subcutaneously into athymic mice. Blot analyses demonstrated the presence and expression of integrated proviral DNAs of both FeLV and myc-FeLV in these cells. They appear, then, to represent cells partially transformed by infection with myc-FeLV(FeLV). The action of feline v-myc in early-passage cells in vitro was compared to that of avian v-myc.