Pre‐copulation intervals,copulation frequencies,and initial progeny sex ratios in two biotypes of whitefly,Bemisia tabaci

The whitefly Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae) is a species complex, and its systematic classification requires controlled crossing experiments among its genetic groups. Accurate information on pre‐copulation intervals, copulation frequencies, and initial frequency of egg fertilization of newly emerged adults is critical for designing procedures for collecting the virgin adults necessary for these experiments. In the literature, considerable variation is reported between B. tabaci populations, with respect to the length of the pre‐copulation interval and the initial frequency of egg fertilization. Here, we used a video‐recording method to observe continuously the copulation behaviour of the Mediterranean/Asia Minor/Africa (B biotype) and the Asia II (ZHJ1 biotype) groups of B. tabaci. We also recorded the initial frequency of egg fertilization, as determined by the sex of the progeny. When adults were caged in female–male pairs on leaves of cotton plants, the earliest copulation events occurred 2–6 h after emergence; at 12 h after emergence 56–84% of the females had copulated at least once, and nearly all (92–100%) had copulated at least once by 36 h after emergence. Both females and males copulated repeatedly. Approximately 80 and 20% of copulation events occurred during the photophase and scotophase, respectively. By 72 h post‐emergence, the females of the B and ZHJ1 biotypes had copulated on average 6.1 and 3.9 times, respectively. When adults were caged in groups on plants 1–13 h after emergence, 30–35% of the eggs deposited during this period were fertilized, and approximately 90% of females were fertilized by the end of the 13 h. Although timing of copulation differed in detail between the two genetic groups, the results demonstrate that B. tabaci adults can start to copulate as early as 2–6 h post‐emergence and the majority of females can become fertilized on the day that they emerge.     

Chromosomal locations of the gene coding for the CD3 (T3) γ subunit of the human and mouse CD3/T-cell antigen receptor complexes

The gene coding for the M _r 26000 chain of the human CD3 (T3) antigen/T-cell antigen receptor complex was mapped to chromosome band 11q23 by using a cDNA clone (pJ6T3 -2), by in situ hybridization to metaphase chromosomes and by Southern blot analysis of a panel of human-rodent somatic cell hybrids. The mouse homolog, here termed Cdg-3, was mapped to chromosome 9 using the mouse cDNA clone pB10.AT3 -1 and a panel of mouse-hamster somatic cell hybrids. Similar locations for the CD3 genes have been described previously. Thus, the corporate results indicate that the CD3 and genes have remained together since they duplicated about 200 million years ago.     

Zinc,copper, selenium,and glutathione peroxidase in blood of 11-yr-old dunedin,New Zealand children

Blood was obtained from 564 11-yr-old children who had participated since birth in a multidisciplinary health and development study. Serum zinc concentration did not differ between the boys and the girls (mean±SD: 91=17 μg/100 mL,n=453). Five-6% of serum zinc values were low; although there was a weak correlation with height, none of the boys with low values were below the 10th percentile for height for this group. Serum copper concentration (112±24 μg/100 mL,n=454) was unrelated to sex, height, weight, body mass index, socioeconomic status (SES), or iron status. Blood selenium concentration (49±10 ng/mL,n=564) was lower than previously reported for Dunedin children; it was higher in children in the lower SES categories. The data represent normal values for healthy, 11-yr-old NZ children.     

External factors involved in the regulation of an extracellular proteinase synthesis in Bacillus megaterium

Summary A mathematical model was formulated to describe the kinetics and stoichiometry of growth and proteinase production in Bacillus megaterium. Synthesis of the extracellular proteinase in a batch culture is repressed by amino acids. The specific rate of formation of the enzyme (r _E) can be described by the formula {ie373-1}, where k ₂ and k ₃ stand for the non-repressible and repressible part of enzyme synthesis respectively, k _{S 2} is a repression coefficient and S ₂ indicates the concentration of amono acids; the values of k ₂ and k _{S 2} depend on the composition of the mixture of amino acids. Even in a high concentration, a single amino acid is less effective than a mixture of amino acids. The dependence of the proteinase repression on the concentration of an external amino acid (leucine) follows the same course as its rate of incorporation into proteins, approaching saturation at concentrations higher than 50 M (half saturation approximately 10 M). However, the total uptake of leucine did not exhibit any saturation even at 500 M external concentration.Symbols X biomass concentration, g/l - E proteinase concentration, unit/l - t time, h - S ₁ concentration of glucose, g/l - S ₂ concentration of amino acids, g/l - specific growth rate, l/h - rE specific rate of enzyme production, unit/g/h - k ₁ growth kinetic constant, l/h - k ₂ product formation kinetic constant (for non-repressible part of enzyme synthesis), unit/g - k ₃ product formation kinetic constant (for repressible portion of enzyme synthesis), unit/g - k _{S 1} saturation constant, g/l - k _{S 2} repression coefficient for a certain amino acid or amino acids mixture, g/l     

Isolation of high molecular weight DNA from wholeEuglena cells

Summary A method for isolating high quality DNA from wholeEuglena cells is described. The procedure consists in: the weakening of the cell pellicle in glycerol avoiding the mechanical disruption of cells and shearing damage in DNA molecules; the decondensation ofEuglena compact chromatin directly inside the cells; the complete dissociation of cells and nucleoproteins in sarkosyl detergent; the optional digestion of proteins and RNA with DNase-free enzymes and the final purification of DNA by isopycnic banding in CsCl gradients. Degradation of DNA is prevented all along the extraction procedure by glycerol, antioxydants, EDTA and sarkosyl detergent. Using the enzymatic digestion step, DNA containing few single-stranded nicks is obtained with a yield approaching 100%. DNA with no single-stranded nick could be obtained with a 35% yield when the enzymatic digestion step was omitted. In both cases, the double-stranded DNA has an average molecular weight equal or greater than 6×10⁷. It is free of contaminants and could be easily digested with restriction enzymes. After digestion with Eco RI and size-fractionation in agarose gel this DNA has permitted specific hybridization of the rDNA sequences with a radioactive rRNA probe.Abbreviations Kbp kilobasepairs - Kb kilobases     

Trifluoperazine Activates and Releases Latent ATP-Generating Enzymes Associated with the Synaptic Plasma Membrane

Neurone-specific enolase (NSE) and the brain form of creatine phosphokinase (CPK-BB) were previously found to be present in rat synaptosomal plasma membranes (SPM) using two-dimensional gel (2-D gel) and peptide analysis; enzymatic activities of these and of pyruvate kinase (PK), all involved in ATP generation, were shown to be "cryptic" unless the SPM were treated with Triton X-100. We now show that enzymatic activation also occurs when the SPM are treated with trifluoperazine (TFP). TFP activation occurred even when the enzymes were membrane associated, showing that solubilization was not responsible for "unmasking" the enzyme activities. When TFP treatment was performed at alkaline instead of neutral pH, NSE and CPK-BB were released as well as PK, nonneuronal enolase, and aldolase which were identified by 2-D gel and tryptic peptide analysis. Other proteins released included calmodulin, actin, and the 70-kilodalton heat-shock cognate protein. Tubulin, synapsin I, and a 35-kilodalton basic protein were largely unaffected. The latter was identified as the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase on the basis of 2-D gel and peptide analyses and subsequent partial sequencing of a rat brain cDNA coding for the same protein. TFP treatment is thus useful for activating latent enzymes as well as for distinguishing enzymes that have a different disposition on the membrane.     

Stability of Lanatoside C content in thein vitro propagatedDigitalis lanata clones

In vitro culture was established from shoot tips ofDigitalis lanata cotyledonous plants. The propagated plant material was rooted, transplanted into soil and grown under field conditions. Lanatoside C content was determined in a total of 20 clones and statistically evaluated by means of variance analysis of unequal-sized samples.In vitro clonal propagation ofD. lanata was found not to affect lanatoside C content. Drug level was dependent on a plant genotype.     

High-affinity uptake of γ-[3H]aminobutyric acid by isolated mouse oligodendrocytes in culture

Oligodendrocytes were isolated from mixed glial cultures of neonatal mouse forebrain and further grown in serum-free hormone supplemented culture medium. Cell populations were identified by indirect immunofluorescence using a range of specific antibodies, revealing a predominantly immature population of oligodendrocytes, the majority expressing the myelin glycolipids galactocerebroside and sulfatide on their plasma membrane. Astroglial contamination was found to be minimal. Simultaneous autoradiography and immunofluorescence demonstrated the presence of a transport system for the major inhibitory neurotransmitter GABA in the oligodendrocytes. The transport system was found to be energy, sodium and temperature dependent. Kinetic analysis revealed a high affinity system, with aK _m of 6.27 M and aV _max of 0.714 nmol/min/mg protein, which is comparable to that found previously for CNS neurons and astrocytes.Special Issue dedicated to Dr. E. M. Shooter and Dr. S. Varon.