An elongation control particle containing the N gene transcriptional antitermination protein of bacteriophage lambda

The N gene transcriptional antitermination protein of bacteriophage lambda is incorporated in vitro into transcriptional elongation complexes containing the E. coli proteins NusA and NusB. The binding of NusA to elongating RNA polymerase is sequence-independent and follows the release of sigma 70. Incorporation of N into the elongation complex requires an N utilization site (nut site) on the DNA template. Incorporation of NusB into the complex requires NusA, ribosomal protein S10, and the boxA component of the nut site. T1 RNAase releases N, but not NusB, from the elongation complex. We therefore propose that an N-modified termination-resistant elongation complex includes an elongation control particle (ECP) containing at least NusA, NusB, S10, N, and an RNA transcript of the nut site.

Formation of lymphocyte colonies under serum-free culture conditions in normal individuals and patients with chronic lymphocytic leukemia

This paper describes a culture system which supports the formation of B cell and some T cell colonies under serum-free conditions in peripheral blood samples of normal individuals and patients with chronic lymphocytic leukemia (CLL) of B cell type. In this system, serum is replaced by bovine serum albumin, transferrin, cholesterol, insulin and catalase or horseradish peroxidase. In addition, it is necessary to add staphylococcus protein A, mitomycin-treated T cells as feeders and phytohemagglutinin leukocyte-conditioned medium as a source of growth factors. The plating efficiency is greatly enhanced when normal cells are incubated with galactose oxidase prior to plating and when CLL cells are exposed sequentially to neuraminidase and galactose oxidase.

[Preliminary study on the nucleic acid hybridization technic in detecting HSV-2 DNA corresponding sequence of cancer tissues of the uterine cervix]

In this paper, 34 samples, 25 from 18 cervical carcinoma patients and 9 from 8 non-cervical carcinoma patients, were assayed using (alpha-32P) dCTP HSV-2 DNA probe and nucleic acid hybridization technic. It was shown that the positive rates of HSV-2 DNA corresponding sequence were 50% (2/4), 36% (5/14) and 12% (1/8) in the in situ cancer, invasive cancer and non-cervical cancer tissues. No HSV was isolated from 7 cancer specimens which showed a positive reaction by nucleic acid hybridization.

Reversal of the effects of cyclosporin A on the production of human interferon-gamma

Previous reports have documented that cyclosporin A (CsA) can inhibit the production of interferon-gamma (HuIFN-gamma) and interleukin-2 (IL-2). In this report we have extended these earlier findings and have demonstrated that the defect in the production of HuIFN-gamma persists even after the CsA is removed and is associated with altered synthesis of other lymphokines, mainly a cytotoxin and leukocyte migration inhibition factor. In the presence of recombinant exogenous IL-2, the effect of CsA on the synthesis of HuIFN-gamma can be reversed depending on the concentrations of both the IL-2 and CsA. In addition, the presence of the calcium ionophore A23187 partially reverses the inhibitory effect of CsA by synergistically enhancing the synthesis of HuIFN-gamma.

First report of an epidemic of diarrhoea in human neonates involving the new rotavirus and biological characteristics of the epidemic virus strain (KMB/R85)

An outbreak of diarrhoea in neonates occurred at the nurseries of the Department of Obstetrics of Zhao Tong Regional Hospital, Yunnan Province, from the middle of August to the end of November, 1985. Fifty-one percent of children were affected 2-8 days after birth. The clinical symptoms were mild; patients mainly had diarrhoea and did not vomit. Rotaviruses were detected in 66.7% by RNA PAGE and in 72.7% by EM. The virus strain designated as KMB/R85 had a typical morphology, which was indistinguishable from that of infantile rotaviruses by EM. The viral RNA genome was composed of 11 segments. The buoyant density in CsCl was 1.377 g/cm3. The KMB/R85 strain possessed a hemagglutinin for rhesus monkey erythrocytes. By ELISA, IEM, and HAI, it was found that KMB/R85 strain did not possess the common group antigen shared by group A rotaviruses and was antigenically similar to the Chinese adult diarrhoea rotavirus (serogroup B).

Size and shape of the Escherichia coli lactose permease measured in filamentous arrays

The Escherichia coli lactose permease has been purified on cation exchanger to contain a minimal amount of phospholipids, i.e., 4-5 mol/mol of permease, in the presence of the detergent dodecyl beta-maltoside at its critical micelle concentration. This preparation is active in galactoside binding. When the detergent level is further reduced by dialysis, the lactose permease forms filaments one molecule wide and up to several micrometers long. The filaments tend to associate laterally to form sheets. Analysis of electron micrographs of negatively stained filamentous arrays indicates an average filament spacing of 51 A and a subunit period of 26-30 A along individual filaments. These values most probably correspond to the dimensions of the lactose permease molecule measured parallel to the membrane plane. In many filaments, the subunits show a stain-penetrated cleft. It suggests that the lactose permease molecule comprises two domains, which may be correlated with internal repeats between the N- and C-terminal halves of the polypeptide sequence.

Demographic variation and survival in discrete population models

Persistence and extinction attributes of a discrete population model are explored on both a finite and an infinite time horizon. For a first-order autonomous nonlinear difference equation, a classification is found of when, for each positive integer N, trajectories go to extinction at time N. The dynamic complexity that is known to permeate difference-equation models is also present in the survival analyses developed here. Also found is an interesting decomposition of the continuum of initial population sizes into intervals where populations are persistent at time N and intervals leading to extinction at time n less than or equal to N.

The effect of corticosteroids and other antineoplastic agents on the generation of leukocyte migration inhibition factor

We have shown that hydrocortisone in physiological concentrations can inhibit the production of leukocyte migration inhibition factor (LMIF), but does not diminish the action of this lymphokine. Other agents tested failed to influence LMIF production. Inhibition of LMIF production by corticosteroids was influenced by the nature of the stimulus used for the production as an effect could be seen with PHA or Con A, but not Staphylococcal enterotoxin A (SEA). Production of LMIF was promptly restored after removal of the steroids. Furthermore, addition of a calcium ionophore to PHA restored the production of LMIF even in the presence of corticosteroids. In contrast, addition of exogenous IL-2 did not correct the defect in lymphokine secretion. We believe that inhibition of the production of LMIF by steroid may lead to defective granulocytic function and thus, predispose to infection.