FORTNIGHTLY BIOLOGY NEWSLETTER
Vol. 2, No. 1
A brief report prepared by the Faculty of the Section of Biological Sciences Purdue University at Fort Wayne
January 18, 1971
MALES OF the solitary englossine bees gather aromatic substances from tropical orchids apparently for marking mating territories where several males are in competition. Both bees and orchids have developed highly differentiated adaptions, and many plant species attract only a single pollinator species. Englossine pollination provides effective isolating mechanisms and apparently has been important in speciation of several orchid groups. Isolation by highly selective fragrance permits sympatric speciation through odor-modifying mutation. Evolution 22 202 (1968) WD
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AFTER CHRONIC MARIJUANA exposure, behavior and brain function change, and the changes extend for a considerable time. Barratt and co-workers at the U. of Texas medical branch, Galveston, made electroencephalograms of cats given daily oral or intraperitoneal doses of a marijuana extract distillate. EEG patterns changed after a few weeks and, after dosage was stopped, remained changed for periods of a few weeks to a few months. At Battelle Memorial Institute, Truitt disclosed that alcohol and marijuana exert many differences in action, although low doses are primarily sedative-depressants of the central nervous system. Most conspicuous are muscular weakness, poor coordination, and loss of balance produced by alcohol in rats injected intravenously with either alcohol or Δ9-3, 4-trans-tetrahydrocannabinol (THC), the major active principle of marijuana. Two striking effects of THC are prolonged catatonia (unresponsiveness) and biting of objects with failure to release. Chem. & Eng. News 49 24 Jan. 4 (1971) BB
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IN THE CHOLODNY-WENT theory explaining positive geotropism in plant roots, root growth is said to be mediated by differentials in auxin concentrations on upper and lower sides of the horizontally positioned root. Chadwick and Burg have demonstrated that inhibition of root growth is actually the result of ethylene gradients in the axis formed by eccentric distribution of the plant hormone, indoleacetic acid. Plant Physiology 45 192 (1970) WD
IN THE U. S. two systems of measures exist side by side: the Customary System and the International System (metric). In the International System (SI), the length unit is the meter. The micron and the millimicron are obsolescent terms being replaced by micrometer and nanometer, respectively. Following is a table of prefixes used in SI:
Prefix Symbol Multiples & Submultiples
tera T 1012
giga G 109
mega M 106
kilo k 103
hecto h 102
deka da 10
deci d 10-1
Prefix Symbol Multiples & Submultiples
centi c 10-2
milli m 10-3
micro u 10-6
nano n 10-9
pico p 10-12
femto f 10-15
atto a 10-18
The results of a study of measures by a committee will be submitted to Congress late in 1971. BB
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A TOBACCO SUBSTITUTE moved one step closer to commercialization. Celanese Fibers Co. disclosed recently that it would build a semiworks facility in Princeton, W. Virginia, for continued evaluation and testing of man-made smoking materials developed by the company. Celanese refuses to reveal details about its tobacco substitute but says it hopes to achieve a product that will offer a new route to the reduction of tar and nicotine and gas-phase constituents in cigarettes. Celanese has test marketed outside the U. S. several blends containing the tobacco substitute. Chem. & Eng. News 49 14 Jan. 4 (1971) BB
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CHLOROPLAST DNA in the brown alga Sphacelaria occurs within a ring-shaped genophore (chromosome). The genophore, in turn, demonstrates a definite pattern of association with the photosynthetic lamellae similar to those in the brown alga Egregia and spinach. Direct connection between DNA molecules and the membrane system is well known in bacteria, and it appears that the association facilitates the replication of DNA molecules in prokaryotic organisms and the nucleic acid containing organelles in eukaryotic cells. J. Ultrastructure Research 29 224 (1969) WD
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