Ultrastructure of erythrocytes and leucocytes of Priapulus caudatus (de Lamarck) (Priapulida)

The marine priapulid Priapulus caudatus has a voluminous body cavity filled with a blood-like fluid containing erythrocytes and leucocytes (amoebocytes). The hematocrit of animals weighing 0.5–14 gm was 2–10%. The erythrocytes contain a hemerythrin blood pigment. The structure of the coelomocytes was studied by light and electron microscopy. The erythrocytes are nucleated and contain marginal bands, vacuoles and occasionally crystals. The cytoplasm has few organelles. The leucocytes are amoeboid motile cells, the cytoplasm of which contains numerous organelles. The most conspicuous of these are oval particles, probably representing developmental stages of lysosomes. Most of these organelles contain tubules stretching from one pole to another. In the hind part of the animal, certain tissues, primarily the posterior warts contain large numbers of coelomocytes. The histological picture is complicated, showing some resemblance to the lymphoepithelial tissues of vertebrates.     

Analysis of a model for random competition

A random competition model is reformulated as an urn model and its behavior is analysed.     

Immunosuppressive activity of antamanide and some of its analogues

In connection with our discovery of a strong immunosuppressive activity of cyclolinopeptide A (CLA), we investigated immunosuppressive properties of antamanide and a number of its analogues, including symmetrical antamanide, and compared them with the activities of cyclosporin A and CLA. The peptides were investigated by using plaque forming cell (PFC), graft-versus-host (GvH), delayed type hypersensitivity (DTH), and autologous rosette formation cell (ARFC) tests. Antamanide and symmetrical antamanide exhibit an immunosuppressive activity lower than CLA. Linear antamanide fragments are also active. At higher concentrations of the latter peptides, toxic effects occur.     

Regeneration of transgenic plants of Prunus armeniaca containing the coat protein gene of Plum Pox Virus

Summary A system was developed which allows the transfer of foreign genes into apricot cultivars. We report the transformation and regeneration of Prunus armeniaca plants with Agrobacterium tumefaciens strain LBA 4404 containing various binary plasmids, pBinGUSint, carrying the marker gene ß-glucuronidase (GUS) and pBinPPVm, carrying the coat protein gene of Plum Pox Virus (PPV). The marker gene GUS was used for optical evaluation of the efficiency of the transformation system. The coat protein gene of PPV was used to introduce coat protein mediated resistance against one of the most important pathogens of stone fruit trees in Europe and the whole Mediterranean area. This is the first report of the successful integration of a viral coat protein gene into a fruit tree species, opening a new perspective on the control of the disease.Abbreviations GUS ß-glucuronidase - PPV Plum Pox Virus - BA 6-benzylaminopurine - NPTII neomycin phosphotransferase II - CP coat protein - CaMV Cauliflower Mosaic Virus - P35S 35S promoter - MS Murashige and Skoog - PCR polymerase chain reaction - P/C/I phenol/chloroform/isoamylalcohol - RNase ribonuclease - dNTP deoxyribonucleosidetriphosphate - DMSO dimethyl sulfoxide     

Silencing of the MEG3 gene promoted anti-cancer activity and drug sensitivity in glioma

Aberrant expression of MEG3 has been shown in various cancers. The purpose of this study is to evaluate the effect of MEG3 on glioma cells and the use of potential chemotherapeutics in glioma by modulating MEG3 expression. Cell viability, migration and chemosensitivity were assayed. Cell death was evaluated in MEG3 overexpressing and MEG3 suppressed cells. MEG3 expression was compared in patient-derived glioma cells concerning IDH1 mutation and WHO grades. Silencing of MEG3 inhibited cell proliferation and reduced cell migration while overexpression of MEG3 promoted proliferation in glioma cells. MEG3 inhibition improved the chemosensitivity of glioma cells to 5-fluorouracil (5FU) but not to navitoclax. On the other hand, there is no significant effect of MEG3 expression on temozolamide (TMZ) treatment which is a standard chemotherapeutic agent in glioma. Suppression of the MEG3 gene in patient-derived oligodendroglioma cells also showed the same effect whereas glioblastoma cell proliferation and chemosensitivity were not affected by MEG3 inhibition. Further, as a possible cell death mechanism of action apoptosis was investigated. Although MEG3 is a widely known tumour suppressor gene and its loss is associated with several cancer types, here we reported that MEG3 inhibition can be used for improving the efficiency of known chemotherapeutic drug sensitivity. We propose that the level of MEG3 should be evaluated in the treatment of different glioma subtypes that are resistant to effective drugs to increase the potential effective drug applications.     

Molecular mechanisms of endotoxin activity

Endotoxin (lipopolysaccharide, LPS), a constitutent of the outer membrane of the cell wall of gramnegative bacteria, exerts a wide variety of biological effects in humans. This review focuses on the molecular mechanisms underlying these activities and discusses structure-function relationships of the endotoxin molecule, its interaction with humoral and cellular receptors involved in cell activation, and transmembrane and intra-cellular signal transduction pathways.     

Mutations in neuromusculin,a gene encoding a cell adhesion molecule,cause nervous system defects

The Drosophila neuromusculin (nrm) gene encodes an immunoglobulin-like (Ig-like) cell adhesion molecule expressed in the precursors of the embryonic peripheral nervous system (PNS), in the midline precursors of the central nervous system (CNS), and in muscles. During the initial phases of CNS axonogenesis, nrm is expressed in cells involved in the development of commissures and longitudinal tracts. Mutations which alter expression of nrm mRNAs cause aberrant development of commissures and longitudinal axon pathways. Defects in the PNS and muscles of nrm mutants are also observed. In most nrm embryos, abnormal development can be detected in a subset of abdominal segments; however, in approximately 1 of 10 nrm embryos, the defects extend to all segments. Herein, we present evidence that nrm plays an important role in early morphogenesis, possibly by mediating or facilitating inductive cell contacts and movements.     

Aspects of the biology of the euryhaline Asian cichlid,Etroplus suratensis

Synopsis Aspects of the biology of the euryhaline Asian cichlid Etroplus suratensis in a coastal lagoon of Sri Lanka were studied for a period of 15 months. Comparisons are made from the catches from the fishery of manmade, inland freshwater reservoirs. Changes in the stock structure in the sublittoral region of the lagoon indicate that recruitment takes place twice a year, during the high rainfall/low salinity periods. The feeding habits of E. suratensis were different in the two habitats. In the lagoon it fed mainly on molluscs and in the freshwater reservoirs on macrophytes. Feeding chronology based on diurnal surveys indicate that it feeds mainly during the daylight hours. The dentition of E. suratensis is adapted for both tearing and crushing (pharyngeal teeth). Distinct differences in the mean relative intestinal length between populations from the coastal lagoon and inland reservoirs were evident and these differences are correlated to their respective feeding habits. Diurnal changes in feeding activity are associated with changes in the stomach pH. The egg-diameter distribution of mature fish indicate that E. suratensis is a single spawner, that it sheds its mature eggs all at once. It is inferred that E. suratensis breeds twice a year but that an individual female is capable of spawning only once a year.     

Indole alkaloids from cell suspension cultures of Rauwolfia serpentina benth

Twelve indole alkaloids belonging to the Ajmaline-, Sarpagine-, Yohimbine-, and Heteroyohimbine-type have been isolated and identified from cell suspension cultures of Rauwolfia serpentina. Ten of the alkaloids were found for the first time in cultured R. serpentina cells. The yield of the main alkaloid vomilenine was 51 times more than that of differentiated plants. Crude enzymes isolated from this cell suspension culture completely metabolize the biogenetic precursor strictosidine under formation of several alkaloidal compounds.     

Studies on the yield and gel strength of agar from Gracilaria domingensis Sonder ex Kuetzing (Gracilariales,Rhodophyta) following the addition of calcium

Studies were carried out on the seasonal variation in yield and gel strength of agar from Gacilaria domingensis with and without the addition of calcium chloride. Extraction was done with and without treatment with 1% hydrochloric acid. The results showed an increase in yield and gel strength when an alkaline solution of calcium was used, but the gel strength was low. For commercial use, Gracilaria domingensis should be mixed with better quality Gracilaria species because of its low gel strength.