Analysis of wheat resistance to the cereal aphidSitobion avenae using electrical penetration graphs and flow charts combined with correspondence analysis

The behaviour ofSitobion avenae (F.), was compared on resistant wheat lines ofTriticum monococcum (L.) and a susceptible variety ofTriticum aestivum (L.). Firstly, stylet penetration activities were monitored with the Electrical Penetration Graph (EPG) technique and subsequently analysed using flow charts combined with correspondence analysis. Plant resistance was shown to be associated with repeated penetrations without access to either the xylem or the phloem, and with numerous failures in starting a sustained sap ingestion (as represented by pattern E2). Access to sieve elements of the phloem did not seem to be much affected on resistant plants but it took the aphid three times as long to produce a sap ingestion pattern when maintained on the resistant lineT. monococcum n^o 44 (Tm44) as compared with aphids maintained on susceptible plants. As a result the total time spent in ingesting from sieve elements was reduced by 72% on Tm44. Secondly, direct observations of freely-moving apterous adults were performed. Aphids did not discriminate between resistant and susceptible wheat during the first 30 min of access to test leaves, but only 4 out of 25 aphids were still probing after eight hours on resistant Tm44. The relevance of these results to possible location of the resistance factor(s) are discussed. Although detection of plant resistance before sieve elements are reached can not be rigorously excluded, the factors involved inT. monococcum resistance toS. avenae undoubtedly occur within the phloem vessels.     

Cell-contact mediated modulation of the sialylation of contactinhibin

Contactinhibin was found to be involved in contact-dependent inhibition of growth. The growth inhibitory activity of contactinhibin is mediated by N-linked oligosaccharides with desialylated -glycosidically linked, terminal galactose residues. Here we show that in sparse human fibroblasts contactinhibin was expressed in a biologically inactive, highly sialylated form both on the plasma membrane and intracellularily, while in confluent cells plasma membrane localized contactinhibin was present in a biologically active, low sialylated form. Plasma membranes were shown to contain a glycoprotein sialidase which is suggested to be engaged in the activation of contactinhibin in a cell contact-dependent manner.     

Detection of oligoclonal T lymphocytes in lymph nodes draining from advanced non-small-cell lung cancer

Despite the combined use of surgery and chemoradiotherapy, the poor prognosis of advanced non-smallcell lung cancer (NSCLC) requires the definition of new therapeutic approaches. The presence of T lymphocytes, with peculiar phenotypic, functional and molecular characteristics within the tumour, suggested the possible use of these cells, expanded in vitro, in protocols of adoptive immunotherapy. We have described how a population of oligoclonal T lymphocytes, derived from advanced NSCLC, can be expanded in vitro and has the capability of lysing autologous cancer cells. What is more important, we observed that patients with advanced NSCLC, treated with TIL expanded in vitro and recombinant interleukin-2, seemed to have a disease-free period longer than that of patients treated with conventional chemoradiotherapy. in an attempt to find new sources of specific lymphocytes for immunotherapy, we describe the analysis of the phenotypic, functional and molecular characteristics of T lymphocytes, derived from lymph nodes draining advanced NSCLC. In this paper we show that these cells, have restriction patterns of T cell receptor chain similar to those detectable in the population of infiltrating T lymphocytes. This finding suggests that T cells derived from draining lymph nodes of advanced NSCLC have peculiar characteristics and can be a suitable source of effector cells for protocols of adoptive immunotherapy in lung cancer treatment.     

Characterization and classification of virus particles associated with hepatitis A. I. Size, density, and sedimentation.

Virus-like particles were purified from stools of patients in an epidemic of hepatitis A in Germany. When reference MS-1 chimpanzee pre-inoculation and convalescent sera were used, the close serological relationship of the purified particles to well-known isolates of hepatitis A could be established. On the other hand, the physicochemical characteristics of the particles were determined in parallel to the characteristics of a marker parvovirus (LuIII) and a marker picornavirus (poliovirus type 2). It could be shown that the majority of the hepatitis A-associated particles band at 1.34 g/ml in CsCl and, like poliovirus, sediment at about 160S. In addition, a distinct hepatitis A antigen was observed, which banded at 1.305 g/ml and sedimented between 50 and 90S. A further component accumulated in the density range of between 1.38 and 1.44 g/ml. However, it seemed to be rather labile. Upon reisolation from CsCl and sedimentation in sucrose, it resolved into a 160S, a 90 to 100S, and a 50S form. The size of the 160S particles (27 to 29 nm) could be readily distinguished from that of the parvovirus (22 to 24 nm). It is concluded, therefore, that hepatitis A-associated virus particles are more likely to be classified with the picornaviruses than with the parvoviruses.     

Phytochrome-mediated control of grana and stroma thylakoid formation in plastids of mustard cotyledons

The etioplast»chloroplast transition in the cotyledons of mustard seedlings (Sinapis alba L.) has been studied by electron microscopy. It was found that the active form of phytochrome, established by a red light pulse pretreatment, increases the initial rate and eliminates the lag of grana and stroma thylakoid formation after the onset of white light 60 h after sowing. The effect of a pretreatment with 15 s red light pulses is fully reversible by 756 nm light pulses. This reversibility is lost within 5 min. Evidence is presented which suggests that the time course of grana and stroma thylakoid formation is not correlated with the time course of the dispersal of the prolamellar body. The different functions of phytochrome and chlorophyll in controlling thylakoid formation are discussed.     

Antagonism with dibenamine, D-600, and Ro 3-7894 to estimate dissociation constants and receptor reserves for cardiac adrenoceptors in isolated rabbit papillary muscles

In papillary muscles isolated from reserpinized rabbits, positive inotropic responses to the alpha (alpha)-adrenergic agonist, (-)-phenylephrine in the presence of 10(7) M timolol and the beta (beta)-adrenergic agonist. (-)-isoproterenol were antagonized with the irreversible alpha-adrenergic antagonist, dibenamine, the irreversible beta-adrenergic antagonist. Ro 3-7894, and the calcium blocker, D-600. D-600 was employed as a functional antagonist of both alpha- and beta-adrenoceptor responses. Dissociation constants (Ka values) for drug-receptor interactions were calculated by the method of Furchgott and used to estimate fractional receptor occupancy and agonist efficacies. Comparison of responses showed that the receptor reserve for cardiac beta-adrenoceptors was greater than for alpha-adrenoceptors. D-600 was an effective inhibitor of both cardiac alpha- and beta-adrenoceptor responses; however, estimates of KA and receptor reserves were similar to estimates using an irreversible antagonist for alpha-but not beta-adrenoceptors.     

Comparison of 4-hydroxynzoate decarboxylase and phenol carboxylase activities in cell-free extracts of a defined, 4-hydroxybenzoate and phenol-degrading anaerobic consortium

Summary Two 4-hydroxybenzoate decarboxylase activities and a phenol carboxylase activity were found in cell-free extracts of a defined, 4-hydroxybenzoate- or phenol-grown consortium. Both decarboxylase activities were loosely membrane-associated and required K⁺ but a different pH and ion strength. Loss of activity of both decarboxylases by EDTA could be compensated by Zn²⁺ ions. The K _m values for 4-hydroxybenzoate and K⁺ of the decarboxylase activities with pH optima at 6.4 or 7.8 were 0.02 and 2.5 or 0.004 and 0.5 mm, respectively. 3,4-Dihydroxybenzoate, 3,4,5-tridydroxybenzoate, 3,5-dimethoxy-4-hydroxybenzoate and 3-chloro-4-hydroxybenzoate were also decarboxylated by both enzyme activities. The phenol carboxylase was a soluble enzyme with its pH optimum at 6.5. It required K⁺, Rb⁺ or NH _inf4 ^sup+ as monovalent, Zn²⁺, Mg²⁺, Mn²⁺ or Ni²⁺ as divalent cations and catalysed the carboxylation of phenol if 2,4-,2,3,4- or 2,4,6-hydroxybezoates were absent. The three enzyme activities were not influenced by Avidin and thus were probably not biotin-dependent enzymes. Offprint requests to: J. Winter     

Purification and characterization of recombinant antistasin: a leech-derived inhibitor of coagulation factor Xa

Antistasin (ATS) is a selective, tight-binding inhibitor of blood coagulation Factor Xa originally isolated from the salivary glands of the Mexican leech Haementeria officinalis. In order to provide sufficient quantities of ATS to further investigate the role of Factor Xa in blood coagulation, a recombinant version of ATS has been produced in an insect baculovirus host-vector system. In this study, we describe the purification and in vitro and in vivo characterization of a single recombinant antistasin (rATS) isoform. The purified protein constitutes a minor isoform relative to the more abundant ATS isoforms present in leech salivary gland extracts. In vitro, rATS inhibits purified human Factor Xa stoichiometrically, prolongs plasma-based clotting assays at nanomolar concentrations, and like native ATS, is cleaved at a single position by Factor Xa during the course of inhibition. An initial evaluation of the in vivo efficacy of rATS was addressed utilizing a rhesus monkey model of mild disseminated intravascular coagulation. rATS was shown to fully suppress thromboplastin-induced fibrinopeptide A generation in a dose-dependent fashion. The availability of rATS should provide a valuable tool for the critical evaluation of the specific role played by Factor Xa in coagulation.     

Evidence for a driving role of ingrowing axons for the shifting of older retinal terminals in the tectum of fish

In amphibians and teleosts, retina and tectum grow incongruently. In order to maintain the retinotopy of the retinotectal projection, Gaze, Keating, and Chung (1974) postulated a shifting of terminals throughout growth. In order to test the possibility that ingrowing retinal fibers are the driving force for this shifting, we induced a permanent retinal projection into the ipsilateral tectum in juveniles of the cichlid fish Haplochromis burtoni. The surface of the tectum had increased (11–18 months later) 2.5–5.8 times, and the surface of the retina 8.6–14 times. Filling of ganglion cells with horseradish peroxidase (HRP) retrogradely from the tectum showed ipsilaterally regenerating ganglion cells only in the center of the retina. The position of ganglion cells indicated that the ipsilateral projection derived only from axotomized and regenerating retinal ganglion cells but not from those newly born. Ipsilaterally projecting retinal fibers showed terminals only in the rostral half of the tectum. Comparison of area of terminations of ipsilaterally projecting ganglion cells at various times after the crush provided no evidence for expansion or a shift into caudal tectal areas throughout the period of growth. These findings are compatible with the idea that newly ingrowing fibers induce older terminals to move caudally.