Phosphorylation of the HTLV-1 matrix L-domain-containing protein by virus-associated ERK-2 kinase.

L-domain-containing proteins from animal retroviruses play a critical role in the recruitment of the host cell endocytic machinery that is required for retroviruses budding. We recently demonstrated that phosphorylation of the p6(gag) protein containing the L-domain of the human immunodeficiency virus type 1 regulates viral assembly and budding. Here, we investigated whether or not the L-domain-containing protein from another human retrovirus, namely the matrix protein of the human T-cell leukemia virus type 1, that contains the canonical PTAP and PPPY L-domain motifs, shares similar functional properties.

The host cell MAP kinase ERK-2 regulates viral assembly and release by phosphorylating the p6gag protein of HIV-1.

The host cell MAP kinase ERK-2 incorporated within human immunodeficiency virus type 1 particles plays a critical role in virus infectivity by phosphorylating viral proteins. Recently, a fraction of the virus incorporated late (L) domain-containing p6(gag) protein, which has an essential function in the release of viral particles from the cell surface, was reported to be phosphorylated by an unknown virus-associated cellular protein kinase (Muller, B., Patschinsky, T.

Stimulation of soil nitrification and denitrification by grazing in grasslands: do changes in plant species composition matter?

Stimulation of nitrification and denitrification by long term (from years to decades) grazing has commonly been reported in different grassland ecosystems. However, grazing generally induces important changes in plant species composition, and whether changes in nitrification and denitrification are primarily due to changes in vegetation composition has never been tested. We compared soil nitrification- and denitrification-enzyme activities (NEA and DEA, respectively) between semi-natural grassland sites experiencing intensive (IG) and light (LG) grazing/mowing regimes for 13 years.

Active cAMP-dependent protein kinase incorporated within highly purified HIV-1 particles is required for viral infectivity and interacts with viral capsid protein.

Host cell components, including protein kinases such as ERK-2/mitogen-activated protein kinase, incorporated within human immunodeficiency virus type 1 (HIV-1) virions play a pivotal role in the ability of HIV to infect and replicate in permissive cells. The present work provides evidence that the catalytic subunit of cAMP-dependent protein kinase (C-PKA) is packaged within HIV-1 virions as demonstrated using purified subtilisin-digested viral particles. Virus-associated C-PKA was shown to be enzymatically active and able to phosphorylate synthetic substrate in vitro.

Interaction of human immunodeficiency virus type 1 Vif with Gag and Gag-Pol precursors: co-encapsidation and interference with viral protease-mediated Gag processing.

Interactions of human immunodeficiency virus type 1 (HIV-1) Vif protein with various forms of Gag and Gag-Pol precursors expressed in insect cells were investigated in vivo and in vitro by co-encapsidation, co-precipitation and viral protease (PR)-mediated Gag processing assays. Addressing of Gag to the plasma membrane, its budding as extracellular virus-like particles (VLP) and the presence of the p6 domain were apparently not required for Vif encapsidation, as non-N-myristoylated Deltap6-Gag and Vif proteins were co-encapsidated into intracellular VLP. Encapsidation of Vif occurred at significantly higher copy numbers in extracellular VLP formed from N-myristoylated, budding-competent Gag-Pol precursors harbouring an inactive PR domain or in chimaeric VLP composed of Gag and Gag-Pol precursors compared with the Vif content of Pr55Gag VLP.

Immunoreactive domains and integrin-binding motifs in adenovirus penton base capsomer.

A panel of nine independent mouse monoclonal antibodies (MAbs) against penton base capsomers of subgenus C adenovirus serotypes 2 (Ad2) and 5 (Ad5) were isolated and characterized. Two of them (1D2 and 5A5), raised against Ad5 virion as the immunogen, bound to sodium dodecyl sulfate (SDS)-resistant and subgenus C-specific epitopes that were not present in subgenus B Ad3 penton base. The 1D2 and 5A5 epitopes were mapped to two distinct regions that did not belong to the main variable region carrying the integrin-binding RGD motif at position 340.

Proteolytic activity in vivo and encapsidation of recombinant human immunodeficiency virus type 1 proteinase expressed in baculovirus-infected cells.

The activity in vivo of HIV-1 proteinase (PR) was analysed in the baculovirus expression system, using eight different constructs of the prt gene under the control of polyhedrin (PH) promoters of various strengths. None of the active PRs was expressed in substantial quantities, and only PH-fused and/or non-functional PR mutants accumulated in high amounts in insect cells. However, enough PR activity was generated from a lengthened PR construct in insect cells to process Gag polyprotein substrate co-expressed in the same cells in trans.

Demonstration of pathological circulating endothelial cells in patients with amaurosis fugax.

The present study was performed in nine patients with amaurosis fugax (AF). Eight of the patients had had at least one attack of AF in the preceding 3 months, and the ninth, a woman aged 35 years, had also had a transient cerebral ischaemic attack (TIA) 5 months previously, with residual hemiparesis. Only one patient, a man aged 51 years, had been given 'anti-platelet' therapy before beginning this study, having had a mycocardial infarct some years before.

Therapeutic trial of the combination in an eye lotion of adrenaline (0.5 or 1%) and guanethidine (3 or 5%) in cases of open-angle glaucoma.

Treatment of open-angle glaucoma has always been problematical, either because of the lack of efficacy, the inconvenience of multiple medication (handled by the patient with difficulty), or due to the high incidence of side effects. This study showed that an association of adrenaline and guanethidine in drop form, used in cases of open-angle glaucoma, achieved a rapid and lasting stabilisation of intraocular pressure. The main advantage of this form is the combination of two active ingredients for instillation twice daily.

[Metabolic changes in the retina after experimental microembolism in the miniature pig (author's transl)].

Experimental microembolisation provokes hemodynamics and metabolic changes in the inner retina. The metabolic modifications are the consequence of focal tissue ischaemia and have as a main feature, the activation of anaerobic glycolysis. This activation produces an increase in the production of lactic acid which, in turn, causes a drop of tissular pH.

[Transmission of the anterior chamber pressure to the center of the vitreous body and to the posterior pole of the eye of the miniature swine. Measurement of isovolumetric and direct pressure].

Experimental variations of the anterior chamber pressure (P.I.C.