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Notes: Summary The present paper describes a species ofLeptosphaerulina occurring on 10 angiospermic hosts belonging to 7 families of dicotyledons. On the basis of perithecial size, shape, septation and size of ascospores, the fungus occurring on all these hosts was considered to be belonging to a single species which was identified asL. australis McAlp. Further work on the taxonomy and nutritional requirements of the fungus is under investigation.

Notes: Summary In this paper in all 6 fungi three of which viz.Helminthosporium dorycarpum, Tetrasporium asterinearum andDiploida sp. growing as hyperparasites onMeliola sp.,Meliola aethiops var.cassiae var. nov. andPhyllachora sacchari spontanei respectively are recorded and described.

Notes: Abstract  The evolution of acute lymphoblastic leukemia from a myelodysplastic syndrome is a very uncommon event. We describe a 46-year-old man in whom refractory anemia with excess blasts (RAEB) evolved to a pre-B acute lymphocytic leukemia. Trisomy 8 was one of the cytogenetic abnormalities in the dysplastic clone and was detected in both peripheral blood and bone marrow smears of interphase cells by the fluorescence in situ hybridization (FISH) technique. Using a chromosome 8 centromeric specific DNA probe we identified the trisomy 8 to be present in lymphoblasts, erythroid precursors, myeloblasts, promyelocytes, myelocytes, metamyelocytes, granulocytes, and monocytes. Our case supports the hypothesis that in MDS the pluripotent precursor cell is affected, and we examine the potential role of FISH for the study and follow-up of some hematological diseases.

Notes: [Auszug] When Chinese hamster cells were arrested at the Gl/S boun-dary of the cell cycle by treatment with 2 mM hydroxyurea for 20 h and subsequently treated for 4-6 h with caffeine (5 mM), the cells entered mitosis without completing DNA synthesis as originally observed in BHK (baby hamster kidney) ...

Notes: Summary Somatic chromosome elimination was identified and its patterns studied in a trisomic (2n=11) with marker genes in Coix aquatica Roxb. In a cross between a recessive trisomic with green base and white style (ccc ii ss) and a dominant disomic having purple base and purple style (CC II SS), all the F1 seedling progeny were purple based because of the presence of C, I and S. For C. to be expressed in seedling base, either I should be absent or S should be present with I. In style colour, however, irrespective of the presence of I and S, C produces purple phenotype. In one trisomic (Ccc ii ss) plant (designated as 4–15) of the F1 progeny, a part of the seedling base was green. All the tillers coming up from the green side of the main tiller also had green base, and those arising on the purple side were purple based. Similarly, the pistillate spikelets on the green side of the main culm and on the tillers with green base were white styled, and the male spikes showed 10 chromosomes. Female spikelets on the purple side of the main tiller and on the tillers with purple base were mostly purple styled and the male spikes had 11 chromosomes. In some of the purple based tillers, however, there were both 11 and 10 chromosomes in different regions or different inflorescence clusters on the tiller. In these tillers, where the chromosome number was 11, style colour was purple, and white style occurred when there were 10 chromosomes. In one tiller, the style colour was purple but the chromosome number was 10. The recessive phenotype of the style in the trisomic conceivably resulted from an elimination of the extra chromosome carrying the dominant allele C. On the basis of the morphological features of the extra chromosome, such as length, centromere position and distribution pattern of the hetero and eupycnotic regions, it was identified as chromosome No. 2 in the complement. It was therefore possible to place with certainty the gene c on this chromosome. Sometimes, however, the extra chromosome carrying c also was eliminated giving 10 chromosomes and purple style. In the other trisomic plants of the F1 progeny, one plant showed 11 chromosomes but in a tiller there were only 10 chromosomes and white styles. In two other plants, although the chromosome number was 11 throughout, white style was present in a single cluster of inflorescences in one plant, and in one pistillate spikelet in the other. In the latter two cases, white style was believed to have arisen as a result of a mutation from C to c or somatic crossing over, giving the genotype ccc in the affected regions. In a single plant, chromosome elimination was observed in only one cell. Apparently the 10-chromosome sectors arose from the 11-chromosome condition by selective elimination of the extra chromosome during mitosis in the primordium giving rise to these sectors. In the affected plants, elimination did not obviously occur at the same stage but at different times in their ontogeny. Instability is probably governed by one or a few major genes, associated with a number of modifiers, exhibiting incomplete penetrance and variable expression. Chromosome elimination did not apparently follow any particular pattern but was erratic. Probably some intracellular environment is necessary to trigger the mechanism governing the elimination into action. The unstable system, occurring in combination with other favourable features like the functional nature of the aneuploid gametes, sexual reproduction, monoecious condition favouring cross pollination and tolerance of extra chromosomes by the sporophyte, could be an important factor in the cytogenetic evolution of the species.

Notes: Summary In gamma-ray treated populations of tomato, one of the plants showed stickiness of chromosomes at meiosis. At diakinesis, some of the bivalents tended to fall apart as univalents, and at about the same time or a little later, the bivalents and/or univalents congregated into groups. At metaphase I, the number of such groups varied from 1 to 14 and the groups were of various sizes; the masses of chromatin in which the individuality of chromosomes seemed to be completely lost were spherical, oval or irregular in outline and freely dispersed in the cytoplasm. Some of the masses were so small that they might possibly represent fragments of chromosomes. As the stage passed to anaphase I, the masses dissolved into individual chromosomes, even though stickiness was still persistent but less intense. Laggards in varying numbers were also found. At completion of meiosis, in some proportion of telophase II cells, persistent laggards were found. Pollen fertility and seed set were low. The selfed M2 progeny of the sticky plant contained a few yellow seedlings which died at the cotyledon stage. Cytological examination of meiosis of some of the individuals of this progeny revealed stickiness again in a majority of plants. Sticky as well as normal plants in M2 were selfed and the M3 generation raised. In progenies of both kinds, yellow lethals were found in proportions that gave a good fit with three green to one yellow seedlings in many cases. The occurrence of a sticky plant in M1 and many such plants in M2 was assumed to be due to a dominant mutation induced by gamma irradiation. This, besides causing sticky meiosis, also produced recessive yellow lethal mutations.

Notes: Summary Interspecific hybrids and amphidiploids of Nicotiana knightiana Goodspeed (n= 12)x N. umbratica Burbidge (n = 23) resembled either parent in some characters and were intermediate in other characters. The F1 hybrids (2n = 35) showed mostly univalents during meiosis, while the amphidiploids (2n = 70) formed bivalents almost regularly. The former were completely sterile and the latter fully male fertile but predominantly female sterile. This female sterility was due to disintegration of the embryo sacs leading to collapsed ovules. The few fertile ovules, however, showed normal development of embryo sac and embryo. The occurrence of fertile and sterile ovules was believed to be due to segregation of the genes governing sterility.