salmonnb: a program for computing cohort‐specific effective population sizes (Nb) in Pacific salmon and other semelparous species using the temporal method

We describe a new method and a computer program salmonn b to calculate the effective number of breeders (N_b) per year in semelparous species with variable age at maturity. The existing temporal method for the ‘salmon’ life history produces an estimate of the harmonic mean N_b in the two sampled years. salmonn b reads genotypic data in standard formats and computes yearly N_b values by combining information from pairwise comparisons of samples taken in 3 or more years. Simulations show that the new method produces unbiased estimates of yearly N_b, and precision is inversely proportional to true effective size.     

EFFECT OF AUXIN AND ANTIAUXIN ON THE GROWTH AND RNA SYNTHESIS OF ETIOLATED PEA INTERNODE

Using etiolated Alaska pea internode segments the followingresults were obtained. An auxin, 2,4-dichlorophenoxyacetic acid, 1 mg/liter, inducedthe elongation growth of the segment and stimulated the biosynthesisof RNA, particularly of messengar RNA, in 3 hr incubation. Thesimilar stimulation of RNA synthesis and of elongation due toindole-3-acetic acid was found in 1 hr incubation. The stimulativeeffect of 2,4-dichlorophenoxyacetic acid on the elongation andon the synthesis of messenger RNA was inhibited by the additionof an antiauxin, transcinnamic acid. Significance of the auxin-inducedsynthesis of messenger RNA in producing protein responsiblefor the stress relaxation of cell wall is discussed. (Received June 13, 1967; )     

Auxin-induced synthesis of TB-RNA in pea stems

The effect of 2,4-dichlorophenoxyacetic acid on RNA synthesisin etiolated pea internode segments was studied. Auxin stimulatedsynthesis of TB-RNA only in short period incubation, suggestingits primary importance in auxin action. The nucleotide compositionof newly synthesized TB-RNA seems to be modified under auxininfluence. (Received February 8, 1969; )     

Noninducible Phenotype exhibited by a Proportion of Female Mice Heterozygous for the <Emphasis Type="Italic">X</Emphasis>-Linked Testicular Feminization Mutation

This article describes the varying degrees of inducibility of two marker enzymes and kidney hypertrophy of Tfm/+ heterozygous female mice.     

Further Characterization of <Emphasis Type="Italic">o</Emphasis><Superscript>s</Superscript> Mutation of Mouse β-Glucuronidase Locus

The operator noninducible mutation of the mouse β-glucuronidase locus is associated with a reduced electro-phoretic mobility for the enzyme. This suggests that the translational repressor, specified by the Tfm locus, recognizes a translatable segment of the messenger RNA it controls.     

FURTHER STUDIES ON THE RNA FUNCTIONAL IN AUXIN ACTION

Avena coleoptile and a respiration-deficient mutant of yeastwhose cells are elongated by the action of auxin in the absenceof GA added were subjected to the phenol method of RNA fractionation."RNA" from the phenol layer promoted the auxin-induced expansionof Jerusalem artichoke tuber slices just as GA did, whereas"RNA" from the water layer was ineffective. The GA-like activityof the former "RNA" was reduced by treatment with RNase or alkali. No active "RNA" was extractable from a respiration-sufficientyeast strain which does not respond to auxin without GA supplemented. (Received August 19, 1964; )     

SPECIES SPECIFIC PATTERN OF CILIOGENESIS IN DEVELOPING SEA URCHIN EMBRYOS

The events of cell division and ciliogenesis in individual blastomeres of developing embryos of the sea urchins Temnopleurus toreumaticus and Hemicentrotus pulcherrimus were followed with a Nomarski differential interference microscope. The number of cell divisions before initiation of ciliogenesis was determined with respect to species. In T. toreumaticus , ciliogenesis began about 4 hr after fertilization at 25°C. The sequence of ciliogenesis was as follows: cilia appeared first on smaller micromeres, followed in order by blastomeres derived from larger micromeres, those from mesomeres and finally those derived from macromeres. Blastomeres originating from mesomeres, macromeres, larger micromeres and smaller micromeres had completed the 8th, 9th, 7th and 5th divisions respectively, before they generated cilia.
In H. pulcherrimus , embryos started to form cilia about 9 hr after fertilization at 18°C. Cilia appeared first on blastomeres of mesomere origin and, then on those of macromere origin. Before initiation of ciliogenesis, descendants of mesomeres and macromeres completed 9 and 10 rounds of cell division. Descendants of larger micromeres and the majority of cells derived from smaller micromeres did not acquired cilia even when the embryo began to rotate within the fertilization membrane. At this stage, the former had completed the 6th division and the latter the 8th division. Cell counts of blastomeres per embryo at the blastula stage also supported this observation.     

Rubisco content and photosynthesis of leaves at different positions in transgenic rice with an overexpression of RBCS

As ribulose 1·5-bisphosphate carboxylase/oxygenase (Rubisco) activity limits light-saturated photosynthesis under present atmospheric condition, the effects of an overexpression of RBCS on Rubisco content and photosynthesis were examined in the leaves at different positions in rice ( Oryza sativa L.). Rubisco content in the transformant was significantly greater in the uppermost, fully expanded leaves but decreased to levels similar to those in wild-type plants in the lower leaves. The mRNA levels of total RBCS and rbcL in these leaves were much less than those in the expanding leaves, where Rubisco synthesis is active, suggesting commensurately low level of synthesis. Although the activation state of Rubisco was lower in the uppermost, fully expanded leaves of the transformant, it recovered to its full level in the lower leaves. As a result, the photosynthetic rate did not differ in leaves at the same position between the transformant and the wild type. Similarly, whole plant biomass did not differ between these genotypes. Thus, we conclude that although the overexpression of RBCS led to an enhancement of Rubisco protein content in the uppermost, fully expanded leaves, it does not result in increased photosynthetic rates or plant biomass, because of an apparent down-regulation in its activation state.     

EFFECT OF AUXIN AND OXALIC ACID ON THE CELL WALL PROPERTY OF AVENA COLEOPTILE

In accelerating the elongation of excised Avena coleoptile cylinders,the effect of oxalic acid was found to be additive to that ofindole-3-acetic acid. Elastic and plastic extensions of the coleoptile cylinder weremeasured by using the plasmolytic method. Both indole-3-aceticacid and oxalic acid increased the elastic extension quickly,while their effect in increasing the plastic extension appeared2 hours after their application. The mechanism of auxin action is discussed in connection withthe effect of removal of calcium from the pectic substance ofthe primary cell wall. (Received November 15, 1960; )