Differential binding of conA and WGA on the cell surface, the role of sialic acid in their expression and the increased activity of sialidase after cis-Platin treatment

It is reported that concanavalin A (conA) and wheat germ agglutinin (WGA) have a differential binding pattern on normal mouse spleen lymphocytes and the surface of Dalton's lymphoma cells. It is suggested that sialic acid on the cell surface controls the expression of lectin binding sites. Further, it has been observed that the increased release of sialic acid from cell surfaces after cis-dichlorodiammine platinum (II) (cis-Platin) treatment is due to the increased activity of sialidase.     

Coexistence of A- and B-form DNA in a single crystal lattice

It is well known that DNA can exist in a variety of conformations which can be interconverted by relatively mild changes in conditions. The in vivo conformation of DNA is usually thought to be the B form, but there is recent evidence that other conformations may be important in DNA-protein recognition. Different fragments of DNA crystallized under virtually identical conditions can form A, B or Z helices. A fragment that adopted an A conformation in a crystal was found in the B conformation in solution, whereas NMR spectroscopy of A-DNA films revealed the presence of a substantial amount of disordered B-DNA. Until now, however, a DNA fragment of a given sequence has not been crystallized in more than one global conformation. We report here an X-ray diffraction study of crystals of the DNA octamer dGGBrUABrUACC. In addition to a 'framework' of A-DNA, which gives discrete X-ray reflections, there are partially disordered B-DNA helices, recognized by their diffuse scattering features.     

MULTIPLE CRITERIA DECISION MAKING： DISCORDANT PREFERENCES AND PROBLEM DESCRIPTION

There are many practical decision problems where decision makers＇ preferences may be inconsistent and contradictory. In this paper, new methods for ordering and classifying multi-attribute objects by discordant collective preferences are suggested. These methods are based on the theory of multiset metric spaces. The proposed techniques are applied to ranking companies and a competitive selection of projects, which are estimated by several experts upon multiple qualitative criteria.     

Cooperative tandem binding of met repressor of Escherichia coli

We present biochemical and genetic data to support the hypothesis that the Escherichia coli met repressor, MetJ, binds to synthetic and natural operator sequences in tandem arrays such that repression depends not only on the affinity of the DNA-protein interaction, but also on protein-protein contacts along the tandem array. This represents a novel form of regulatory switch. Furthermore, there seems to be homology between the organization of the met and trp operators.     

Supernumerary chromosomes inDrosophila nasuta albomicana

Summary Supernumerary chromosomes have been detected in the karyotype ofD.n. albomicana. Their number varies from one to three. They are the smallest elements in the karyotype. Karyotypes ofD.n. albomicana with and without supernumerary chromosomes have been presented.     

A novel type of cardiac calcium channel in ventricular cells

Calcium influx is vital for several aspects of cardiac activity, so it is important to ask if heart cells possess a single or multiple types of Ca channel. Only one Ca channel type has been identified in patch-clamp studies of unitary current, despite suggestions to the contrary from whole-cell recordings in heart cells and unitary recordings from other cells. Here we describe a novel type of cardiac Ca channel with several properties that distinguish it from the hitherto-identified Ca channel in heart cells. Its conductance in isotonic Ba is small (8 pS), and is no larger in Ba than in Ca. It activates and inactivates at relatively negative potentials and remains functional long after patch excision. It is insensitive to dihydropyridines such as nimodipine and the Ca agonist Bay K 8644, and is more resistant to block by external Cd than the previously described type of cardiac Ca channel.     

Differential binding of conA and WGA on the cell surface,the role of sialic acid in their expression and the increased activity of sialidase after cis-Platin treatment

Summary It is reported that concanavalin A (conA) and wheat germ agglutinin (WGA) have a differential binding pattern on normal mouse spleen lymphocytes and the surface of Dalton's lymphoma cells. It is suggested that sialic acid on the cell surface controls the expression of lectin binding sites. Further, it has been observed that the increased release of sialic acid from cell surfaces aftercis-dichlorodiammine platinum (II) (cis-Platin) treatment is due to the increased activity of sialidase.To whom reprint requests should be addressed.     

Presynaptic neurones may contribute a unique glycoprotein to the extracellular matrix at the synapse

As the extracellular matrix at the original site of a neuromuscular junction seems to play a major part in the specificity of synaptic regeneration, considerable attention has been paid to unique molecules localized to this region. Here we describe an extracellular matrix glycoprotein of the elasmobranch electric organ that is localized near the nerve endings. By immunological criteria, it is synthesized in the cell bodies, transported down the axons and is related to a glycoprotein in the synaptic vesicles of the neurones that innervate the electric organ. It is apparently specific for these neurones, as it cannot be detected elsewhere in the nervous system of the fish. Therefore, neurones seem to contribute unique extracellular matrix glycoproteins to the synaptic region. Synaptic vesicles could be involved in transporting these glycoproteins to or from the nerve terminal surface.