Limits of phenotypic markers for the diagnosis of megakaryoblastic leukemia

Diagnosis of megakaryoblastic and early erythroid leukemia requires the use of differentiation markers that in most cases permit their precise diagnosis. In some cases, their use can be misleading. Here we report and discuss some examples. A platelet peroxidase (PPO) activity is detected in most cases of early erythroid leukemias as well as in the CFU-E-like cells of normal marrow, thus providing evidence that PPO activity must be studied along with other (immunologic or ultrastructural) markers to permit a reliable diagnosis of megakaryoblastic leukemia. Ferritin molecules an erythroid marker, could be detected as a cluster at ultrastructural level in leukemic platelets and in micromegakaryocytes of one patient. However, in blasts of the erythroid lineage, ferritin molecules are also either dispersed in the cytoplasm or localized in theta granules. Immunologic markers have also their own limit. Indeed, in one patient, GB IIb and IIIa were detected on erythroid blasts, resulting in a phenotype very similar to HEL cells. Carbonic anhydrase (CA) I, an early erythroid marker, was detected in the platelets of four leukemic patients and was present along with an increased expression of CA II. This study emphasizes the fact that precise diagnosis of leukemia cannot be performed with a single marker of differentiation, but requires the simultaneous use of several lineage restricted markers.     

Anther culture of kale (Brassica oleracea L. convar.acephala (DC.) Alef.)

The pollen development and androgenic ability of 18 kale (Brassica oleracea convar.acephala) genotypes was observed during an anther culture study. Anther culture was successful in 6 of the genotypes and the highest yield obtained was 17 embryos per 100 anthers plated. Two stages of anther development were identified as being responsive to anther culture. The first and most responsive was that corresponding to the late uninucleated stage and the second to the late binucleated stage. These stages correspond with the onset of mitotic events in the microspores. Pollen viability was studied and low viability was noted which declined to zero after 9 days of anther culture. The initial viability level however was not clearly related to androgenic ability. The significance of the production of haploid and dihaploid kale genotypes in the study and breeding of resistance to clubroot is discussed.     

Modelling the dynamics of an antigenic peptide using NMR relaxation data.

The internal dynamics of a cyclic peptide which was designed to mimic an antigenic loop of the haemagglutinin, is studied through heteronuclear relaxation along the 13C alpha-1H alpha vectors and through homonuclear relaxation along the 1H alpha-1HN and 1H beta-1H beta' vectors. Order parameters are extracted from the longitudinal and cross-relaxation data. Molecular dynamics simulations are performed and the order parameters are calculated in different ways from the trajectories. The simulation, which is performed in vacuo, gives smaller order parameters (vector motions of larger amplitude) than the experimental results. However, the general features of the experimental order parameters are reproduced by the molecular dynamics simulation. The flexibility of the molecule can then be investigated from the results of the molecular dynamics. It shows that the mobility observed through the order parameters is due to motions in flanking regions, remote from the observed vectors.     

Fishers' knowledge and seahorse conservation in Brazil

From a conservationist perspective, seahorses are threatened fishes. Concomitantly, from a socioeconomic perspective, they represent a source of income to many fishing communities in developing countries. An integration between these two views requires, among other things, the recognition that seahorse fishers have knowledge and abilities that can assist the implementation of conservation strategies and of management plans for seahorses and their habitats. This paper documents the knowledge held by Brazilian fishers on the biology and ecology of the longsnout seahorse Hippocampus reidi. Its aims were to explore collaborative approaches to seahorse conservation and management in Brazil; to assess fishers' perception of seahorse biology and ecology, in the context evaluating potential management options; to increase fishers' involvement with seahorse conservation in Brazil. Data were obtained through questionnaires and interviews made during field surveys conducted in fishing villages located in the States of Piauí, Ceará, Paraíba, Maranhão, Pernambuco and Pará. We consider the following aspects as positive for the conservation of seahorses and their habitats in Brazil: fishers were willing to dialogue with researchers; although captures and/or trade of brooding seahorses occurred, most interviewees recognized the importance of reproduction to the maintenance of seahorses in the wild (and therefore of their source of income), and expressed concern over population declines; fishers associated the presence of a ventral pouch with reproduction in seahorses (regardless of them knowing which sex bears the pouch), and this may facilitate the construction of collaborative management options designed to eliminate captures of brooding specimens; fishers recognized microhabitats of importance to the maintenance of seahorse wild populations; fishers who kept seahorses in captivity tended to recognize the condtions as poor, and as being a cause of seahorse mortality.     

Science – A life fully lived: Joe Sodroski wins the 2006 Retrovirology Prize

The 2006 M Jeang Retrovirology Prize for HIV research has been awarded to Dr Joe Sodroski     

Sterility in hybrid cattle. I. Distribution of constitutive heterochromatin and nucleolus organizer regions in somatic and meiotic chromosomes.

The distribution of constitutive heterochromatin and nucleolus organizer regions (NOR's) in somatic as well as in meiotic chromosomes of Bos taurus, Bos banteng, Bison bison, and their hybrids are analyzed. C-bands are present in the centromeric regions of every autosome. The X chromosome does not show a distinct C-band in the centromeric region, whereas the Y chromosome contains an appreciable amount of C-band material. In somatic metaphases, NOR's are present on the telomeric ends of five pairs of autosomes. During pachytene, five autosomal bivalents contain NOR's on their terminal ends. Meiotic preparations made from sterile bulls did not contain stages beyond the degenerating pachytene, which are C-banding, more frequently showed clustering of heterochromatin than did the pachytene stage in normal bulls.