Dynamical Systems Approach to Higher-level Heritability

To explain higher-level heritability, we propose a dynamical systems approach, based on simulations of the high-dimensional replicator equation with mutation dynamics. We assume that all variants are generated from within the groups of variants through mutations. Simulating the equation with a random interaction matrix and possible variants, we report that this system tends to have many attractors, of fixed point, chaotic and quasiperiodic type. In a chaotic attractor, special gene-like variants appear to control the heritability ofthe system, in the sense that removal of the variants would easily enable the system to depart from the attractor. Those variants do not predominate in thepopulation size, but have the lowest net reproduction and mutation rates on average. Because their rate of growth is small, they are named neutral phenotypes. Additionally, combinatorial effects of these neutral variants to the entire system are reported.     

Replication of X chromosomes in complete moles

Summary DNA replication patterns of X chromosomes in complete hydatidiform moles were studied using cultured fibroblasts from three 46,XX moles resulting from duplication of a haploid sperm, and from a 46,XY mole originating from dispermy. Control cultures included skin fibroblasts from an adult woman and a female fetus as well as PB lymphocytes from an adult woman. Cultures were treated with 5-bromodeoxyuridine for the last 2–4h of the S phase, and the chromosome slides prepared were stained by the Hoechst 33258-Giemsa procedure. Each of the three XX moles studied revealed one early-replicating and one late-replicating X chromosomes, while the XY mole revealed one early-replicating X chromosome. DNA replication patterns of molar X chromosomes were similar to those of adult and fetal fibroblasts, but different from those in adult lymphocytes. These findings indicate that DNA replication kinetics of molar fibroblasts are tissue-specific rather than origin- or developmental-stage specific.     

Lung protein leaks in ventilated lambs: effects of gestational age

To study the protein permeability properties of the ventilated premature lung, we delivered groups of eight lambs at 122 and 135 days gestational age and ventilated the lambs equivalently. The lambs at 122 days gestational age had been treated with natural sheep surfactant at birth, and both groups of lambs had similar pH and blood gas values to 3 h of age. Three groups of lambs at 146 days gestational age also were studied for comparison; four lambs were ventilated to normalized PCO2 values, four lambs were ventilated equivalently to the premature lambs with supplemental CO2 used to normalize PCO2 values, and four lambs were treated with natural surfactant and ventilated similarly to the preterm lambs. The percent recovery into an alveolar wash and lung tissue of 131I-albumin given by intravascular injection and of 125I-albumin given into the airways was measured in each animal after killing at 3 h of age. Full-term lambs had a small bidirectional leak of albumin to and from the alveoli and lung tissue. The recovery of intravascular 131I-albumin in the alveolar wash was 5.8- and 4.1-fold higher in lambs at 122 and 135 days gestational age, respectively, than in full-term lambs. The loss of 125I-albumin from the airways and alveoli also increased as gestational age decreased. The bidirectional flux of albumin to and from the alveoli increased as gestational age decreased in the prematurely delivered and ventilated lambs.     

New PCR-RFLP analysis for the mouse Tnfsf6gld gene caused by a point mutation in the Tnfsf6 [tumor necrosis factor (ligand) superfamily, member 6] locus.

A new polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis was developed for genetic typing of the mouse Tnfsf6gld mutation. An artificial restriction site was introduced to the mouse Tnfsf6gld mutation by PCR amplification using a modified primer. The three genotypes of the Tnfsf6 locus (Tnfsf6gld/Tnfsf6gld, Tnfsf6gld/+, and +Tnfsf6-gld/+Tnfsf6-gld) could be distinguished clearly and easily. This PCR-RFLP analysis was found to be useful for the identification of the mouse Tnfsf6gld mutation.     

Identification of 4-Chloroindole-3-acetic Acid and Its Methyl Ester in Immature Seeds of Vicia amurensis (the Tribe Vicieae), and Their Absence from Three Species of Phaseoleae

The natural chlorinated auxins 4-chloroindole-3-acetic acid(4-Cl-IAA) and its methyl ester (4-Cl-IAA Me ester) were found,in addition to IAA and its Me ester, by gas chromatography-massspectrometry in immature seeds of Vicia amurensis, a Vicieaespecies. In contrast, only non-chlorinated, IAA and IAA Me esterwere present in immature seeds of three Phaseoleae species.These results are further evidence of the wide distributionof 4-Cl-IAA and its Me ester in various Vicieae. (Received October 3, 1986; Accepted December 22, 1986)     

Abrogation of the capacity of delayed-type hypersensitivity responses to alloantigens by intravenous injection of neuraminidase-treated allogeneic cells

BALB/c or C3H/He mice were inoculated i.v. with allogeneic spleen cells untreated or treated with neuraminidase. Appreciable or potent anti-allo-delayed-type hypersensitivity (DTH) responses were observed when mice were inoculated i.v. with untreated allogeneic cells or inoculated i.v. with those cells followed by s.c. immunization with untreated allogeneic cells. In contrast, i.v. inoculation of neuraminidase-treated allogeneic cells (presensitization) not only failed to induce any significant anti-allo-DTH responses but also abolished the capability of the animals to develop DTH responses after s.c. immunization, indicating the tolerance induction. This tolerance was alloantigen-specific, and rapidly inducible and long lasting. The induction of suppressor cell activity was demonstrated in tolerant mice. However, this activity was associated only with the tolerant state around 4 to 7 days after the i.v. presensitization, but was no longer detected in mice more than 14 days after the presensitization, although these mice exhibited complete tolerant state. When spleen cells from such tolerant mice were transferred i.v. into 600 R x-irradiated syngeneic recipient mice alone or together with normal syngeneic spleen cells, these tolerant spleen cells themselves failed to induce DTH responses but did not exhibit suppressive effect on the generation of DTH responses induced by normal spleen cells co-transferred. These results indicate that i.v. administration of neuraminidase-treated allogeneic cells results in the induction of alloantigen-specific tolerance which is not always associated with the induction of suppressor cell activity but rather with the elimination or functional impairment of alloantigen-specific clones.