New chromosome characteristics of the monozoic tapeworm Caryophyllaeus laticeps (Cestoda, Caryophyllidea)

Summary The karyotype of a caryophyllidean tapeworm Caryophyllaeus laticeps (Pallas, 1781) from the freshwater bream Abramis brama (L.) caught in the Slovak part of the River Tisa, was described and originally inspected for amount of heterochromatin and its chromosome localization. The chromosome set comprised nine metacentric and one submetacentric (No. 3) pairs (2n = 20). The chromosomes were up to 12.0 ± 2.5 μm long and the mean total length of haploid genome (TLC) reached 80.6 μm that represents one of the highest yet recorded values among tapeworms. C-banding and staining with fl uorescent dyes DAPI and YOYO1 revealed a distinct banding pattern explicitly on chromosomes with centromeric bright heterochromatin bands present on all 10 chromosome pairs; no pair showed any interstitial heterochromatin. A complete course of spermatocyte meiosis and dynamics of nucleolus formation and degradation during meiotic division was described.

Adiponectin Produced by Lymphocytes Inhibits Granulopoiesis.

Previous studies by our group have shown that normal unstimulated lymphocytes produce a protein which inhibits colony formation of granulopoietic progenitors, but has no effect on erythroid progenitors. Therefore, this inhibitor was initially designated GIA (granulopoietic inhibitory activity). GIA was identified as a glycoprotein of approximately 30 kDa, with a pI of 7.9 - 8.4. Futhermore, we demonstrated that this inhibitor may have physiological significance in that its production is altered in patients with neutropenia. GIA has proved difficult to characterise to date since it is produced in relatively low amounts although it has a high specific biological activity. Adiponectin is an adipokine reported to share many of the inhibitory characteristics of GIA and has been demonstrated to act as a negative regulator of hematopoiesis and immune response. This study aimed to determine whether GIA is adiponectin or if it represents an adiponectin-like molecule. Lymphocyte conditioned medium (LCM) from lymhocytes cultured at 1 X 106 cells/ml in HL-1 minimal medium was used as a source of GIA. Inclusion of LCM as 10% of the top layer of agar in a myeloid colony assay inhibited growth of CFU-GM by 52 ± 11 % (n=3), confirming the presence of the inhibitory activity. RNA and protein from lymphocytes and LCM harvested over a 7 day culture period were subsequently investigated for adiponectin expression. Western blot analysis demonstrated a distinct banding pattern in days 3-7 LCM corresponding to monomers, dimers, trimers and greater. This is consistent with adiponectin which circulates as a multimer of trimers. Characterisation of GIA at the transcript level confirmed that GIA is in fact adiponectin. The N-terminal collagenous domain, C-terminal globular domain and full length adiponectin were amplified by RT-PCR analysis. Adiponectin is thought to be secreted exclusively from adipocytes and much of our current knowledge of this molecule relates to its metabolic functions. Our study provides evidence that adiponectin is also produced by lymphocytes and may play a role in the pathogenesis of neutropenia.

Immunological localization of ribosomes in striated rat muscle. Evidence for myofibrillar association and ontological changes in the subsarcolemmal:myofibrillar distribution

Ribosome distribution in skeletal-muscle fibres was investigated immunohistochemically by using polyclonal antibodies raised against large-ribosomal-subunit proteins isolated from rat liver. Immunoblot analysis showed the antibodies to recognize five major proteins of the large subunit; these were identified as L4, L6, L7, L15 and L17 by two-dimensional electrophoresis. Immunohistochemistry of frozen rat skeletal-muscle sections showed staining of both the subsarcolemmal and intermyofibrillar cytoplasm. A distinct banding pattern was observed, and when peroxidase and phase-contrast images of the same field were compared by image analysis the anti-ribosome staining was found to correspond to the A-bands. These results suggest that a proportion of muscle ribosomes are present in the myofibrillar cytoplasm in a regular fashion, possibly associated with myosin. Densitometric analysis of the peroxidase immunostaining showed that the ratio of myofibrillar to sub-sarcolemmal ribosomal material was lower in muscle from 51-day-old rats compared with those from 14-day-old animals.

Localization of chromosomal protein HMG-1 in polytene chromosomes of Chironomus thummi.

The distribution of accessible antigenic sites in the chromosomal protein high mobility group one (HMG-1) in Chironomus thummi polytene chromosomes is visualized by immunofluorescence. The results indicate that (a) HMG-1 is distributed in a distinct banding pattern along the entire length of the chromosomes; (b) the banding pattern obtained with fluorescent antibody does not strictly correspond to that observed by phase-contrast microscopy; and (c) the amount of HMG-1 increases, and the fluorescent banding pattern changes, during the development of the organism. Our findings suggest that the protein may be involved in the modulation of the structure of selected loci in the chromosome.

GIEMSA STAINING OF HETEROCHROMATIC AREAS OF HUMAN CHROMOSOMES FOR IDENTIFICATION

A simple technique is described for differential staining of human chromosomes with Giemsa. The procedure involves DNA denaturation with a methanol-acetic acid fixative, and subsequent annealing using a saline solution. This technique has a number of advantages over quinacrine fluorescence, and gives a more distinct banding pattern. It is a rapid, inexpensive procedure and can be done with existing equipment and material in most cytogenetic laboratories.