Increase in total protein following infection of CV-1 cells with SV40 virus as assayed by flow cytometry

Summary The changes in cell size and total protein were determined for G1-arrested, contact-inhibited CV-1 cells infected with Simian virus 40 (SV40). The assays used were the Biorad total protein assays (Bradford and DC protein assays) on a standard number of cells, total protein as assayed by fluorescein isothiocyanate (FITC) and SR101 by flow cytometry, orthoganol (90°) light scatter by flow cytometry, and direct microscopic measurement with an ocular micrometer. Uninfected CV-1 cells and two cell lines with variations in DNA content (diploid vs. tetraploid) were used as controls for the studies presented. The results demonstrated a 40–60% increase in total protein at 32 to 42 h postinfection. These increases were similar to values obtained as control cells progress through the cell cycle. At later times postinfection (>42 h), total protein decreased due to cellular changes resulting from viral replication and cell death.     

Invited Review Free Radicals in Foods

During the last decade increasing attention has been given to the role of free radicals in biological oxidations. The subject has been of increasing interest to both the food scientist and the physiologist. Free radical scavengers in the form of both indigenous and added antioxidants are necessary for the successful preservation of food; free radicals are increasingly being implicated in the onset of, among others, ischaemic heart disease and for protection against these diseases it is suggested that the dietary intake of the antioxidant vitamins should be increased especially for diets high in polyunsaturated fats. ^1,2 Convenience and snack foods which absorb substantial amounts of frying oils are being increasingly consumed. Since poly-unsaturated fatty acids are particularly susceptible to oxidation by free radicals during the storage, cooking and frying of foods, the potential risk of exposure to lipid degradation products' is likely to have increased. In foods the non-enzymic and lipoxygenase catalysed oxidation of polyunsaturated fatty acids, β-carotene and vitamin A can result in the loss of essential nutrients and the development of off-flavours.     

Use of Genetic and Physical Mapping to Locate the Spinal Muscular Atrophy Locus between Two New Highly Polymorphic DNA Markers

The gene for autosomal recessive forms of spinal muscular atrophy (SMA) has recently been mapped to chromosome 5ql3, within a 4-cM region between the blocks D5S465/D5S125 and MAP-1B/D5S112. We identified two new highly polymorphic microsatellite DNA markers—namely, AFM265wf5 (D5S629) and AFM281yh9 (D5S637)—which are the closest markers to the SMA locus. Multilocus analysis by the location-score method was used to establish the best estimate of the SMA gene location. Our data suggest that the most likely location for SMA is between locus D5S629 and the block D5S637/D5S351/MAP-1B/D5S112/D5S357. Genetic analysis of inbred SMA families, based on homozygosity by descent and physical mapping using mega-YACs, gave additional information for the loci order as follows: cen–D5S6–D5S125/D5S465–D5S435–D5S629–SMA–D5S637–D5S351–MAP–1B/D5S112–D5S357–D5S39–tel. These data give the direction for bidirectional walking in order to clone this interval and isolate the SMA gene.     

Effect of growth regulators onin vitro propagation ofFicus benjamina cv. Exotica

Stem internodes with axillary buds were excised from 5-year old trees ofFicus benjamina cv. Exotica. The effect of 6-benzylaminopurine (BAP), gibberellic acid (GA₃), indole-3-acetic acid (IAA), naphthaleneacetic acid (NAA), and 2,4-dichlorophenoxyacetic acid (2,4-D) on shoot growth and proliferationin vitro was investigated. Multiple shoots were developed after 3–4 weeks from stem internodes with axillary buds incubated in Murashige and Skoog (MS) medium supplemented with phloroglucinol (PG) and BAP. Optimum shoot proliferation took place in the presence of 1.0 mg l⁻¹ BAP. Shoots obtained could be elongated in a medium with 0.5 mg l⁻¹ GA₃ prior to their rooting. The root initiation was successfully induced on MS medium either with IAA at 0.5–0.1 mg l⁻¹ or in plant growth regulator-free medium. All rooted plantlets were subsequently transferred to a peat, humus and perlite mixture in a culture room with high humidity and covered with plastic bags. After one month the plantlets were established for growing in a greenhouse. Communicated by J. TUPY     

Superovulatory response of ovarian follicles of Wave 1 versus Wave 2 in heifers

Experiments were designed to test the hypotheses that ovarian follicular response to superstimulatory treatment initiated during Wave 1 is equivalent to that of Wave 2, and recovery rate and quality of ova embryos derived from follicles of Wave 1 are equivalent to those derived from follicles of Wave 2. In a preliminary experiment (Experiment 1), heifers were given Folltropin-V (20 mg NIH-FSH-P1, im, bid for 5 d) beginning the day after emergence of the first (n=10) or second (n=10) follicular wave of the estrous cycle, equivalent to approximately Day 1 and Day 10, respectively (Day 0=ovulation). Luteolysis was induced with cloprostenol (500 mug im, bid) on the fourth day of treatment. Fewer (P<0.05) ovulations per heifer were induced in the Wave 1 group than in the Wave 2 group (4.6+/-1.0 vs 9.1+/-1.3). However, the interval from wave emergence to initiation of treatment was found, in retrospect, to have been longer (P<0.05) in the Wave 1 group, i.e., treatment was initiated relatively later with respect to wave emergence. Experiment 2 was designed to correct this disparity and to initiate the same treatment protocol on the day of wave emergence rather than the day after (n=21 per Wave group). There was no difference between Wave 1 and Wave 2 groups in the interval from wave emergence to initiation of treatment (0.4+/-0.1 d), the number of ovulations detected by ultrasonography (6.6+/-1.0 vs 8.2+/-1.7), the number of CL detected at slaughter (6.5+/-0.9 vs 8.1+/-1.8), the total number of ova embryos recovered (5.2+/-0.7 vs 5.1+/-0.8), or the number of fertilized embryos collected (2.8+/-0.6 vs 3.0+/-0.6). In addition, there was no difference between groups in the proportion of heifers that ovulated in either experiment; collectively, luteolysis and ovulation was induced in 58 of 60 heifers. The results supported the general hypothesis that follicles and oocytes of the first and second follicular waves are equivalent in the response to superstimulatory treatment. Regardless of which follicular wave, initiation of treatment near the time of wave emergence appears critical for maximal superovulatory response. Because of the consistency in the time of emergence of Wave 1 (day of ovulation) and equivalence in superovulatory response, use of Wave 1 rather than subsequent follicular waves may be more convenient and time-sparing in superovulation programs; the day of estrus (day before ovulation) may be used as a consistent point of reference for the start of treatment.     

Effect of Sodium on Phosphate Uptake in Unicellular and Filamentous Cyanobacteria

The effect of Na⁺ on phosphate uptake was studied in four strainsof cyanobacteria: Synechococcus PCC 7942, Gloeothece PCC 6501,Phormidium sp. and Chlorogloeopsis PCC 6912. Phosphate uptakewas stimulated by Na⁺ in all cases. Li⁺ and K⁺ acted as partialanalogues for Na⁺. Half-saturation [K_1/2(Na⁺)] of phosphateuptake was reached with Na⁺ concentrations ranging from 317µM in Chlorogloeopsis to 659 µM in Phormidium. Theconcentration of phosphate required to reach half-saturationof phosphate uptake [K_1/2(P_i)]was not changed by the presenceof Na⁺. (Received April 11, 1994; Accepted July 5, 1994)     

Comparative methods for isolation of Volcaniella eurihalina exopolysaccharide

Summary The best isolation procedure to obtain the EPS of Volcaniella eurihalina was centrifugation at 36,000 x g for 60 min and precipitation with cold ethanol after tangential filtration with 100,000 D ultrafilters. Ion chromatography showed that this EPS contained glucose, rhamnose and mannose in a molar ratio of 3.2: 1.1:1, respectively.     

Preliminary caged‐field trial,using the fungal pathogen Zoophthora radicans brefeld (zygomycetes: entomophthorales) against the diamondback moth Plutella xylostella L. (lepidoptera: Yponomeutidae) in the UK

Zoophthora radicans Brefeld was tested for control of Plutella xylostella L. in a caged‐field trial. No infection was seen in control cages, but between 36% and 68% of larvae in live samples, and 38% and 55% of larvae at the final harvest, were infected in inoculated cages, suggesting the biological control potential of this fungus.     

Effect of fructose-1,6-bisphosphate on glutamate uptake and glutamine synthetase activity in hypotix astrocyte cultures

Astrocytes are important in regulating the microencironment of neurons both by catabolic and synthetic pathways. The glutamine synthetase (GS) activity observed in astrocytes affects neurons by removing toxic substances, NH₃ and glutamate; and by providing an important neuronal substrate, glutamine. This glutamate cycle might play a critical role during periods of hypoxia and ischemia, when an increase in extracellular excitatory amino acids is observed. It was previously shown in our laboratory that fructose-1,6-bisphosphate (FBP) protected cortical astrocyte cultures from hypoxic insult and reduced ATP loss following a prolonged (18–30 hrs) hypoxia. In the present study we established the effects of FBP on the level of glutamate uptake and GS activity under normoxic and hypoxic conditions. Under normoxic conditions, [U-¹⁴C]glutamate uptake and glutamine production were independent of FBP treatment; whereas under hypoxic conditions, the initial increase in glutamate uptake and an overall increase in glutamine production in astrocytes were FBP-dependent. Glutamine synthetase activity was dependent on FBP added during the 22 hours of either normoxic- or hypoxic-treatment, hence significant increases in activity were observed due to FBP regardless of the oxygen/ATP levels in situ. These studies suggest that activation of GS by FBP may provide astrocytic protection against hypoxic injury.