Circadian rhythms in Neurospora crassa: Lipid deficiencies restore robust rhythmicity to null frequency and white-collar mutants

The conidiation rhythm in the fungus Neurospora crassa is a model system for investigating the genetics of circadian clocks. Null mutants at the frq (frequency) locus (frq9 and frq10) make no functional frq gene products and are arrhythmic under standard conditions. The white-collar strains (wc-1 and wc-2) are insensitive to most effects of light, and are also arrhythmic. All three genes are proposed to be central components of the circadian oscillator. We have been investigating two mutants, cel (chain-elongation) and chol-1 (choline-requirer), which are defective in lipid synthesis and affect the period and temperature compensation of the rhythm. We have constructed the double mutant strains chol-1 frq9, chol-1 frq10, chol-1 wc-1, chol-1 wc-2, cel frq9, cel frq10, and cel wc-2. We find that these double mutant strains are robustly rhythmic when assayed under lipid-deficient conditions, indicating that free-running rhythmicity does not require the frq, wc-1, or wc-2 gene products. The rhythms in the double mutant strains are similar to the cel and chol-1 parents, except that they are less sensitive to light. This suggests that the frq, wc-1, and wc-2 gene products may be components of a pathway that normally supplies input to a core oscillator to transduce light signals and sustain rhythmicity. This pathway can be bypassed when lipid metabolism is altered.

Genes, peoples, and languages

The genetic history of a group of populations is usually analyzed by reconstructing a tree of their origins. Reliability of the reconstruction depends on the validity of the hypothesis that genetic differentiation of the populations is mostly due to population fissions followed by independent evolution. If necessary, adjustment for major population admixtures can be made. Dating the fissions requires comparisons with paleoanthropological and paleontological dates, which are few and uncertain. A method of absolute genetic dating recently introduced uses mutation rates as molecular clocks; it was applied to human evolution using microsatellites, which have a sufficiently high mutation rate. Results are comparable with those of other methods and agree with a recent expansion of modern humans from Africa. An alternative method of analysis, useful when there is adequate geographic coverage of regions, is the geographic study of frequencies of alleles or haplotypes. As in the case of trees, it is necessary to summarize data from many loci for conclusions to be acceptable. Results must be independent from the loci used. Multivariate analyses like principal components or multidimensional scaling reveal a number of hidden patterns and evaluate their relative importance. Most patterns found in the analysis of human living populations are likely to be consequences of demographic expansions, determined by technological developments affecting food availability, transportation, or military power. During such expansions, both genes and languages are spread to potentially vast areas. In principle, this tends to create a correlation between the respective evolutionary trees. The correlation is usually positive and often remarkably high. It can be decreased or hidden by phenomena of language replacement and also of gene replacement, usually partial, due to gene flow.

Biological clocks

Circadian rhythms describe biological phenomena that oscillate with an ≈24-hour cycle. These rhythms include blood pressure, body temperature, hormone levels, the number of immune cells in blood, and the sleep-wake cycle. In this paper, we will focus on common genes between species that are responsible for determining the circadian behavior, especially some transcription factors (i.e., switch genes) that serve to regulate many circadian rhythm genes. The intent of this summary is to introduce the common molecular mechanism of biological clocks between flies and humans and then to describe the research from three laboratories that was presented in the session.

A general additive distance with time-reversibility and rate variation among nucleotide sites.

As additivity is a very useful property for a distance measure, a general additive distance is proposed under the stationary time-reversible (SR) model of nucleotide substitution or, more generally, under the stationary, time-reversible, and rate variable (SRV) model, which allows rate variation among nucleotide sites. A method for estimating the mean distance and the sampling variance is developed. In addition, a method is developed for estimating the variance-covariance matrix of distances, which is useful for the statistical test of phylogenies and molecular clocks. Computer simulation shows (i) if the sequences are longer than, say, 1000 bp, the SR method is preferable to simpler methods; (ii) the SR method is robust against deviations from time-reversibility; (iii) when the rate varies among sites, the SRV method is much better than the SR method because the distance is seriously underestimated by the SR method; and (iv) our method for estimating the sampling variance is accurate for sequences longer than 500 bp. Finally, a test is constructed for testing whether DNA evolution follows a general Markovian model.

The bear watches the dragon. The Russian debate on China. OSW Point of View Number 31, February 2013

Most participants in the Russian public debate seem to agree in their evaluation of the present condition of Russian-Chinese relations. There is awareness of increasing inequality between these two powers and Russia’s weakening position as compared to China.Those who share the optimistic view see co-operation with China as an opportunity for the Russian economy and a key element of Russia’s multi-directional foreign policy, an opportunity for Russia to avoid unilateral dependence on the West. The pessimists view the deepening co-operation with China through the prism of threats resulting from the increasing imbalance in bilateral relations. The greatest source of concern is the model of economic relations, which is often referred to as neo-colonial, where Russia’s role is reduced to that of a supplier of raw materials to China. The possible consequences are evaluated in different ways, ranging from the political subordination of Russian interests the Chinese ones to real loss of control over the Russian Far East. Those who share such views believe that Moscow should slow down its rapprochement with China and search for other partners in Eastern Asia, relations with whom could counterbalance the Chinese influence.

Atomic clocks of the National Bureau of Standards.

Mode of access: Internet.

The novels and stories.

v. 1. The late Mrs. Null.--v. 2. The Squirrel Inn. The Merry Chanter.--v. 3. Rudder Grange.--v. 4. The hundredth man.--v. 5. Ardis Claverden.--v. 6. The great war syndicate. The stories of the three burglars. The knife that killed Po Hancy. Dusky philosophy.--v. 7. The house of Martha.--v. 8. Pomona's travels. Euphemia among the pelican's. The Rudder Grangers in England. Pomona's daughter.--v. 9. The adventures of Captain Horn.--v. 10. Mrs. Cliff's yacht.--v. 11. The great stone of Sardis. The water-devil.--v. 12. The girl at Cobhurst.--v. 13. The casting away of Mrs. Lecks and Mrs. Aleshine. The vizier of the two-horned Alexander.--v. 14. The associate hermits.--v. 15. Stories. [v.]1: The lady or the tiger? The discourager of hesitancy. The transferred ghost. The spectral mortgage. Every man his own letter-writer. Thar same old coon. Our story. Derelict. On the training of parents. A borrowed month. The baker of Barnbury. The watchmaker's wife.--v. 16. Stories. [v.]2: A tale of negative gravity. Asaph. The remarkable page. The Cloverfield's carriage. A story of assisted fate. My bull-calf. As one woman to another. Our fire-screen. My terminal moraine. Plain fishing.--v. 17. Stories. [v.]3: The griffin and the minor canon. Old Pipes and the dryad. The bee-man of Orn. The queen's museum. The clocks of Rondaine. Christmas before last; or, the fruit of the fragile palm. Prince Hassak's march. The battle of the third cousins. The banished king. The philopena. Amos Kilbright: his adscititious experiences. The Christmas shadrach. The bishop's ghost and the printer's baby. The philosophy of relative existences.--v. 18. Stories. [v.]4: The magic egg. "His wife's deceased sister." The widow's cruise. Captain Eli's best ear. Love before breakfast. The staying power of Sir Rohan. A piece of red calico. The Christmas wreck. My well and what came out of it. Mr. Tolman. My unwilling neighbor. Our archery club.--v. 19. Afield and afloat: The Buller-Podington compact. The romance of a mule-car. The governor-general. Old Applejoy's ghost. Struck by a boomerang. The skipper and El Capitan. "Come in, new year." A sailor's knot. The great staircase at Landover Hall. The ghosts in my toewer. The landsman's tale.--v. 20. Kate Bonnet: the romance of a pirate's daughter.--v. 21. John Gayther's garden.--v. 22. The captain's toll-gate.--v. 23. A bicycle of Cathay. With a memorial sketch of Mr. Stockton and a bibliography of his works.

Dog-watches at sea /

Mode of access: Internet.

Collectaneous epitaphs : chiefly designed to assist surviving relations in fixing upon suitable inscriptions, for the tombs and grave-stones of deceased friends ... /

Includes index.

Observations made in astronomy, magnetism and meteorolgy.

Vols. for 1841-1914 include Rates of box and pocket chronometers on trial for purchase by the Board of Admiralty (varies slightly); 1888-1914 includes Rates of chronometer watches on trial for purchase by the Board of Admiralty (varies slightly); 1838,1845-19 include Report of the Astronomer Royal to the Board of Visitors (these titles also issued separately)

British Manufacturing Industries. Edited by G.P. Bevan.

Imperfect; wanting the volume entitled, "Paper, by Prof. Archer, Printing, by Joseph Hatton, etc."

Dermatology Hospital. One of two general wards

Built 1918. Buildings and Grounds Dept., architects. Torn down 1932. Located east of Glen, downhill and behind western-most hospital building

Detroit Rackham

Harley & Ellington, architects. W.E. Wood Co., contractor. Built from July 1940 to January 1942. Built jointly for the Engineering Society of Detroit and the University as an Extension Service facility in Detroit. Funded by the Horace H. and Mary A. Rackham Fund. Sculptures on exterior by Marshall Fredericks.