Post‐glacial history and introgression in Abies (Pinaceae) species of the Russian Far East inferred from both nuclear and cytoplasmic markers

Aim The main aim of the present study is to infer the post‐glacial history of Abies species from north‐east Asia and to test the hypotheses that coastal Abies populations suffered less from climatic fluctuations during Pleistocene glacial periods than their more continental counterparts, and that Sakhalin was a major area of introgression. Location Natural ranges of the fir species Abies nephrolepis, Abies sachalinensis and Abies holophylla in the Russian Far East, and of Abies gracilis, which is endemic to the Kamchatka Peninsula. Methods Nineteen populations were sampled for allozyme analysis. Seventeen of these populations were also screened for variation at two paternally inherited chloroplast DNA microsatellite loci (cpSSR) and variation at one maternally inherited mitochondrial marker (nad4‐3/4). Finally a subset of 11 populations was analysed with amplified fragment length polymorphism (AFLP). Comparisons were made with already available Abies sibirica data. For all sets of markers, we estimated genetic diversity and differentiation using an analysis of molecular variance (AMOVA). Population clustering was assessed with a Bayesian approach implemented in structure v.2.3. Results Among the three major species, A. sibirica, A. nephrolepis and A. sachalinensis, A. sachalinensis demonstrated the highest cytoplasmic and nuclear diversity and the most continental species, A. sibirica, the lowest. Both nuclear and mitochondrial DNA markers revealed the presence of a transitional zone on Sakhalin Island between A. nephrolepis and A. sachalinensis of south Sakhalin. The structure analysis delivered very clear results confirming the admixed origin of A. sachalinensis, with a genetic contribution from A. nephrolepis. No variation in cytoplasmic markers was found in A. gracilis, suggesting the occurrence of a recent bottleneck. Main conclusions There is a clear reduction of genetic diversity in Abies species from the Pacific coast into the continent. The higher diversity in A. sachalinensis could have two causes: a larger effective population size in the islands due to relatively stable climatic conditions and consequently less pronounced demographic fluctuations in population size and/or hybridization with continental and Japanese populations. Sakhalin Island is a major transitional zone for conifer species. Finally, the fir from Kamchatka, A. gracilis, should be regarded as a separate species closely related to the A. nephrolepis–A. sachalinensis complex.     

Cell-by-cell flow cytometric analysis of chromosomes

The authors discuss various aspects of a recently developed method permitting a detailed flow cytometric analysis of the individual cell karyotypes such as instrumentation, histochemistry, data proceeding algorithms. Possible drawbacks of the method and the ways of their overcoming are considered. Results of analysis of the Chinese hamster cells are presented that illustrate the possibilities of the method, including the metaphase chromosome distribution according to their fluorescence intensity, the analysed cell distribution according to their chromosomes number, the table in which the individual cell karyotypes are distributed according to their fluorescence. The results obtained show that the developed method may be successfully used for investigating chromosomal iNstability and heterogeneity of the mammalian cells.     

1988 Gordon Conference on Theoretical Biology and Biomathematics Tilton Academy, Tilton, New Hampshire, U.S.A., 13–17 June 1988

Announcement

1988 Gordon Conference on Theoretical Biology and Biomathematics Tilton Academy, Tilton, New Hampshire, U.S.A., 13–17 June 1988     

Recovery of acetylcholinesterase activity after irreversible inhibition by organophosphorous compounds in embryonic development

1. Recovery of acetylcholinesterase (AChE) activity was studied using the embryos of sea urchins Strongylocentrotus intermedius and S. nudus, embryos of axolotl Ambystoma mexicanum and in the chick embryo muscle culture treated by "irreversible" organophosphorous inhibitors (OPI). 2. AChE activity was assayed by a modified Ellman's procedure. 3. It follows from the data obtained that, unlike the plutei of sea urchins and the monolayer culture of chick embryo muscle cells, the embryos of axolotl show a compensatory increase in AChE biosynthesis after inhibition by OPI. 4. This mechanism is assumed to be related to the presence of a well developed neuromuscular system in the A. mexicanum embryos. 5. It is possible that acetylcholine accumulated as a result of partial AChE inhibition is responsible for the compensatory increase in AChE biosynthesis.     

Characterization of a new hybrid mink-mouse clone panel: chromosomal and regional assignments of the GLO,ACY, NP,CKBB, ADH2, and ME1 loci in mink (Mustela vison)

To expand the mink map, we established a new panel consisting of 23 mink-mouse clones. On the basis of statistical criteria (Wijnen et al. 1977; Burgerhout 1978), we developed a computer program for choice of clones of the panel. Assignments of the following mink genes were achieved with the use of the hybrid panel: glyoxalase (GLO), Chromosome (Chr) 1; acetyl acylase (ACY), Chr 5; creatine phosphokinase B (CKBB), Chr 10; alcohol dehydrogenase-2 (subunit B) (ADH2), Chr 8. Using a series of clones carrying rearrangements involving mink Chr 1 and 8, we assigned the gene for ME1 to the short arm of Chr 1 and that for ADH2 to Chr 8, in the region 8p12-p24. Mapping results confirm the ones we previously obtained with a mink-Chinese hamster panel. However, by means of an improved electrophoretic technique, we revised the localization of the gene for purine nucleoside phosphorylase (NP), which has been thought to be on mink Chr 2. It is reassigned to mink Chr 10.     

Cloning and inactivation of a chromosomal copy of the imidazole glycerophosphate dehydratase (HIS) gene from Hansenula polymorpha]

A gene for imidazole glycerophosphate dehydratase (HIS) has been selected from the library of Hansenula polymorpha genes by complementation of Escherichia coli hisB mutations or his3 mutation of Saccharomyces cerevisiae. Inactivation of the gene in Hansenula polymorpha strain 48V, as well as Leu(-)-Leu+ conversion of phenotype and arising of antibiotic G418 resistance resulted from transformation of the strain by the linear DNA molecules of the cloned HIS-gene with the in vitro inserted LEU2 gene from Saccharomices cerevisiae and KmR gene. The Southern hybridization analysis of the Leuf+His- G418R clones representing 1-2% of transformants population together with the DNA analysis of the monospore clones from the hybrid Leu+His-G418R transformant tetrad and tester strain have revealed the locus specific nature of the clones.     

Effect of acute and chronic deprivation of catecholaminergic system activity induced by 6-hydroxydopamine on the behavior of the rat

On 202 male rats of Wistar line, a study was carried out of the effect of chronic and acute deprivations of the brain CA-systems activity resulting from administration of 6-OHDA on investigating behaviour and learning. Chronic deprivation of CA-systems activity by neonatal administration of 6-OHDA (100 mg/kg subcutaneously) and their acute deprivation by intracerebral administration of 6-OHDA to adult rats (150 mkg in each lateral ventriculus) was accompanied by similar deep changes of behaviour. Both forms of deprivation reduced the investigating activity of the animals in the open field. In both cases, the above 6-OHDA dozes sharply impeded the learning of animals with emotionally negative reinforcement, with no significant influence on learning with emotionally positive reinforcement. Both forms of deprivation of CA-systems activity weakened the reaction of frustration elicited by a sharp reduction of food reinforcement.     

Effect of the segregation of neutral red, acridine orange and ammonium chloride by L cells (subline LSM) on lysosomal hydrolase activity

Kinetics of Neutral red (NR) and Acridine orange (AO) uptake by cultured L cells (subline LSM) has been studied. It was found that the uptake of both NR and AO, with their constant concentrations in the medium was characterized as a two-phase process. During 2 hours, these cells concentrated as much as 90% of the total amount of NR and AO taken up during the whole incubation period. The segregation and accumulation of NR, AO as well as NH4Cl took place in lysosomes. NR and AO concentrations within the cells exceed by 600 and 400 times, respectively, those in the medium. NR, AO and NH4+ accumulation in cells resulted in inhibition of the activity of the following lysosomal hydrolases: cathepsins B and D, acid lipase, N-acetyl-beta,D-glucosaminidase, beta-galactosidase, acid phosphatase and galactosyltransferase, the latter being a marker of Golgi apparatus. The effect of lysosomal enzyme activity inhibition on the cell economy, and a possible role of lysosomotropic agents as regulators of the lysosomal apparatus functional activity are discussed.