A user-friendly biological workstation

Learning methods developed by artificial intelligence research teams are very efficient for biological sequences analysis but they need running on large computers accessed by terminals. These computers are interfaced with standard displays involving long and unpleasant alphanumerical data handling. The "biological work station" is a personal computer with a color graphic screen providing a user-friendly interface for the artificial intelligence learning programs running on large computers. It provides to biologist a graphical convenient tool for sequence analysis built with efficient man-machine communication methods such as multiwindows, icons and mouse selection. It allows the biologist to edit and display sequences in an efficient and natural way, showing off directly on color pictures the data and the results of learning programs.     

Electrical conductivity of bilayer lipid membranes in electrolytic solution

The electrical conductivity of bilayer lipid membranes (BLM) of oxidized cholesterol has been measured separately in bathing solutions of sodium sulphate, sodium chloride, sodium bromide, sodium iodide and also in bathing solutions of iodine and iodine containing these salts. An attempt has been made to explain the conduction of electric current across the membranes.     

Successful artificial insemination in the giant panda (Ailuropoda melanoleuca) at ueno zoo

Successful breeding of the giant panda (Ailuropoda melanoleuca) following artificial insemination was achieved at the Ueno Zoo in 2 consecutive years (1985 and 1986). The first cub, born in June 1985, unfortunately died 43 hours after birth from being crushed by the mother panda; the second cub, born in June 1986, has been growing in good health. Electroejaculation and artificial insemination procedures were performed after immobilization with diazepam (0.1 mg/kg) and ketamine HCL (4.0–5.0 mg/kg). Semen of the male panda was collected by electroejaculation using a rectal probe with a diameter of 2.0 cm and with eight rings as electrodes. Stimulation of the male was given with 3 V (30–40 mA) over a 5-sec period with 5-sec intervals. The female panda exhibited estrus between late February and early March in 1985 and also between mid-january and early February 1986. Increased excretion of urinary total estrogen showed coincidentally at maximum behavioral estrus, and a gradual rise of pregnanediol level was followed by artificial insemination. The gestational length for the first pregnancy was 110 days and that of the second 121 days.     

Artificial seeds of alfalfa (Medicago sativa L.). Induction of desiccation tolerance in somatic embryos

Summary The use of somatic embryos from cell culture systems in the clonal propagation of plants would be greatly facilitated if the somatic embryos could be dried and stored in a dormant state similar to true seeds. A cell culture system was developed for alfalfa (Medicago sativa L.) line RL34 which gave high yields of somatic embryos in an approximately synchronized pattern. These somatic embryos were treated with abscisic acid (ABA) at the cotyledonary stage of development to induce desiccation tolerance. With no visual preselection, approximately 60% of the dried embryos converted into plants upon reimbibition. When high quality embryos were selected prior to drying, 90 to 100% conversion rates were observed. The timing of the application of ABA in terms of embryo development was critical with an optimum being at cotyledonary stage spanning approximately 4 days; thus, synchronized embryo development is required for optimal expression in bulk samples. The vigor of the seedlings from dried somatic embryos was greater than those from embryos which had not been dried, but remained substantially lower than those from true seeds.     

QUANTITATIVE GENETICS OF SPRINT RUNNING SPEED AND SWIMMING ENDURANCE IN LABORATORY HOUSE MICE (MUS DOMESTICUS)

We tested the hypothesis that locomotor speed and endurance show a negative genetic correlation using a genetically variable laboratory strain of house mice (Hsd:ICR: Mus domesticus). A negative genetic correlation would qualify as an evolutionary “constraint,” because both aspects of locomotor performance are generally expected to be under positive directional selection in wild populations. We also tested whether speed or endurance showed any genetic correlation with body mass. For all traits, residuals from multiple regression equations were computed to remove effects of possible confounding variables such as age at testing, measurement block, observer, and sex. Estimates of quantitative genetic parameters were then obtained using Shaw's (1987) restricted maximum-likelihood programs, modified to account for our breeding design, which incorporated cross-fostering. Both speed and endurance were measured on two consecutive trial days, and both were repeatable. We initially analyzed performances on each trial day and the maximal value. For endurance, the three estimates of narrow-sense heritabilities ranged from 0.17 to 0.33 (full ADCE model), and some were statistically significantly different from zero using likelihood ratio tests. The heritability estimate for sprint speed measured on trial day 1 was 0.17, but negative for all other measures. Moreover, the additive genetic covariance between speeds measured on the two days was near zero, indicating that the two measures are to some extent different traits. The additive genetic covariance between speed on trial day 1 and any of the four measures of endurance was negative, large, and always statistically significant. None of the measures of speed or endurance was significantly genetically correlated with body mass. Thus, we predict that artificial selection for increased locomotor speed in these mice would result in a decrease in endurance, but no change in body mass. Such experiments could lead to a better understanding of the physiological mechanisms leading to trade-offs in aspects of locomotor abilities.     

Alkaloid level in narrow-leafed lupin, Lupinus angustifolius, influences green peach aphid reproductive performance

Two viviparous parthenogenetic clones of the green peach aphid, Myzus persicae (Sulzer), one collected from Rydalmere, New South Wales (NSW), and the other from South Perth (SP), Western Australia, were reared on radish, Raphanus sativus L. cv. Scarlet Globe, under controlled conditions. The NSW clone was fed on simple artificial diets containing alkaloid extracted from narrow-leafed lupin, Lupinus angustifolius L. cv. Fest., and its reproductive performance monitored over 112 h. Forty (40) h into the experiment and thereafter, aphids on the control diet (sucrose solution) produced significantly more offspring (P<0.05) than those on diets containing alkaloid. In a separate experiment, apterae of each clone were caged on three lines (cv. Yorrel, cv. Danja and 84L:441) of narrow-leafed lupin, and allowed to reproduce. The first three offspring were retained, and all developed to 3rd or 4th instar stage. Two nymphs were removed, and the remaining nymph reared through. All three lines produced adults. The number of young produced were counted over 11 days. Fecundity of the SP clone was lower on line 84L:441, but there was no difference in the fecundity of the NSW clone. Phloem exudate and green tissue was concomitantly collected from all lines, and analysed by GC-MS for the alkaloids lupanine and 13-hydroxylupanine. Line 84L:441 contained the highest level of total alkaloids in both phloem and tissue. All experiments indicate that alkaloid level may suppress fecundity of green peach aphids.     

Characterization and application of soybean YACs to molecular cytogenetics

Yeast artificial chromosomes (YACs) are widely used in the physical analysis of complex genomes. In addition to their value in chromosome walking for map-based cloning, YACs represent excellent probes for chromosome mapping using fluorescence in situ hybridization (FISH). We have screened such a library for low-copy-number clones by hybridization to total genomic DNA. Four clones were chosen for chromosome tagging based upon their low or moderate signal. By using degenerate oligonucleotide-primed PCR (DOP-PCR), we were able to use relatively small amounts of soybean YAC DNA, isolated directly by preparative pulsed-field gel electrophoresis, as FISH probes for both metaphase chromosome spreads and interphase nuclei. FISH chromosomal analysis using the three of the clones as probes resulted in relatively simple hybridization patterns consistent with a single homologous locus or two homoeologous loci. The fourth YAC probe resulted in a diffuse hybridization pattern with signal on all metaphase chromosomes. We conclude that YACs represent a valuable source of probes for chromosomal analysis in soybean.     

Assays for the effects of volatile compounds from artificially damaged cotyledons of subterranean clover on the redlegged earth mite, Halotydeus destructor

The effects on the redlegged earth mite (Halotydeus destructor) (Acarina: Penthaleidae) of volatile compounds released from artificially damaged cotyledons of subterranean clover (Trifolium subterraneum L.), a host plant, were investigated with different assays. Mites were repelled by the volatile compounds in flask tube and in trimmed cotyledon disc tests. No differences could be shown between different tissue amounts and between resistant and susceptible varieties. When a membrane sachet was used containing either 2-(E)-hexenal, a compound produced by damaged subclover cotyledons, or the total volatile compounds collected from damaged cotyledons of Dalkeith (susceptible) admixed with 1% glucose, mites gathered to low but were deterred by high concentrations of the compounds. Volatile compounds collected from the resistant variety DGI007 were more deterrent than those from the susceptible Dalkeith. Membrane sachets containing 30 p.p.m. of 2-(E)-hexenal and 1% glucose were less preferred than cotyledons of Dalkeith (susceptible) but were not different from DGI007 (resistant). By increasing the glucose concentration to 5%, the membrane sachets with 30 p.p.m. of 2-(E)-hexenal were preferred to cotyledons of either variety. The results indicate that the membrane feeding technique provides a sensitive way of assaying volatile compounds from damaged subclover cotyledons against the mite.     

Genetic analysis of agronomic traits in a cross between sugarcane (Saccharum officinarum L.) and its presumed progenitor (S. robustum Brandes & Jesw. ex Grassl)

Saccharum robustum Brandes & Jesw. ex Grassl has been suggested as the immediate progenitor species of cultivated sugarcane (S. officinarum L.) [4]. Chromosome pairing and assortment in these two species were previously studied by genetic analysis of single-dose DNA markers in parents in and 44 F₁ progeny of a cross between euploid, meiotically regular 2n=80S. officinarum LA Purple andS. robustum Mol 5829 [2]. This same population was subsequently clonally propagated and evaluated in replicated trials for quantitative traits important to sugarcane breeders. Numbers of stalks, tasseled stalks, and stalks with smut, and the average diameter of two stalks were determined one day prior to harvest. At harvest, plant material from each plot was weighed and evaluated for pol (sucrose content) and fiber percentages. Clones were significantly different (P<0.01) for all traits analyzed. Associations of 83 single-dose arbitrarily primed PCR genetic markers with quantitative trait loci (QTL) of recorded traits was determined by single-factor ANOVA, and multiple regression. QTL analysis revealed markers significantly (P<0.05) associated with the expression of each trait analyzed. Markers associated with QTL after multiple regression were tested for digenic linear × linear epistatic interactions. The various multilocus models explained between 23% and 58% of the total phenotypic variation and 32% and 76% of the genotypic variation for the various traits. Digenic interactions were uncommon. Implications for marker-assisted selection in sugarcane and sugarcane domestication are discussed.