In vitro production of interleukin 1 by normal and malignant human B lymphocytes

In this study, the capacity of normal and neoplastic B lymphocytes to release interleukin 1 (IL 1) has been investigated. Peripheral blood B cells from normal donors were isolated by depletion of E rosetting cells and by positive selection of cells expressing surface immunoglobulin (sIg) or the B1 marker. Peripheral blood B cells from patients with B cell chronic lymphocytic leukemia (B-CLL) were purified by removal of E rosetting cells followed by complement-mediated cytotoxicity with selected monoclonal antibodies. All of the normal B cell suspensions and the large majority of the B-CLL cells produced in culture high amounts of IL 1 in the absence of any apparent stimulus. Control experiments ruled out that small numbers of monocytes in the B cell suspensions could represent the source of IL 1. These data support the contention that B cells participate to the immune response as accessory cells for T cell activation not only by physically presenting antigen, but also by releasing IL 1.     

Production of B cell growth factor by a Leu-7+, OKM1+ non-T cell with the features of large granular lymphocytes (LGL)

The present study reports the characterization of a non-T cell from human peripheral blood which is capable of releasing BCGF. This BCGF-producing non-T cell had a T3-, T8-, Leu-7+, OKM1+, HLA-DR-, Leu-11- surface phenotype and was likely to belong to the so-called large granular lymphocyte (LGL) subset because: after fractionation of non-T cells according to the expression of Leu-7 or HLA-DR markers, it was found in the Leu-7+, HLA-DR- fractions that were particularly enriched in LGL; it co-purified with LGL on Percoll density gradients; and it expressed Leu-7 and OKM1 markers that are shared by a large fraction of LGL. Although co-purified with cells with potent NK capacities, the BCGF-producing cell was not cytotoxic, because treatment of Leu-7+ cells with Leu-11 monoclonal antibody and complement abolished the NK activity but left the BCGF activity unaltered. The factor released by this LGL subset was not IL 1 or IL 2 mistakenly interpreted as BCGF, because: a) cell supernatants particularly rich in BCGF activity contained very little or no IL 1 or IL 2; b) BCGF-induced B cell proliferation was not inhibitable by anti-Tac antibodies (this in spite of the expression of IL 2 receptor by a proportion of activated B cells); and c) BCGF activity was absorbed by B but not T blasts.     

Novel Miscanthus hybrids: Modelling productivity on marginal land in Europe using dynamics of canopy development determined by light interception

New biomass crop hybrids for bioeconomic expansion require yield projections to determine their potential for strategic land use planning in the face of global challenges. Our biomass growth simulation incorporates radiation interception and conversion efficiency. Models often use leaf area to predict interception which is demanding to determine accurately, so instead we use low-cost rapid light interception measurements using a simple laboratory-made line ceptometer and relate the dynamics of canopy closure to thermal time, and to measurements of biomass. We apply the model to project the European biomass potentials of new market-ready hybrids for 2020–2030. Field measurements are easier to collect, the calibration is seasonally dynamic and reduces influence of weather variation between field sites. The model obtained is conservative, being calibrated by crops of varying establishment and varying maturity on less productive (marginal) land. This results in conservative projections of miscanthus hybrids for 2020–2030 based on 10% land use conversion of the least (productive) grassland and arable for farm diversification, which show a European potential of 80.7–89.7 Mt year⁻¹ biomass, with potential for 1.2–1.3 EJ year⁻¹ energy and 36.3–40.3 Mt year⁻¹ carbon capture, with seeded Miscanthus sacchariflorus × sinensis displaying highest yield potential. Simulated biomass projections must be viewed in light of the field measurements on less productive land with high soil water deficits. We are attempting to model the results from an ambitious and novel project combining new hybrids across Europe with agronomy which has not been perfected on less productive sites. Nevertheless, at the time of energy sourcing issues, seed-propagated miscanthus hybrids for the upscaled provision of bioenergy offer an alternative source of renewable energy. If European countries provide incentives for growers to invest, seeded hybrids can improve product availability and biomass yields over the current commercial miscanthus variety.     

Fc-receptors for IgG and IgM immunoglobulins on human T lymphocytes: mode of re-expression after proteolysis or interaction with immune complexes.

The susceptibility to proteolysis and the mode of re-expression of receptors for IgM or IgG present on two different subpopulations of human T lymphocytes (T.M and T.G cells, respectively) have been investigated. The IgM receptor was highly susceptible to both trypsin and pronase, whereas the IgG receptor was resistant to trypsin and sensitive only to high concentrations of pronase. The receptors have been removed by treating purified human T cells with pronase and their reappearance on the cell surface has been followed in vitro. The IgM receptors on the cell surface were detectable within 2 hr and the resynthesis was completed in 6 hr. IgG receptors were detectable in 4 to 6 hr and the resynthesis completed within 12 hr. When protein synthesis was inhibited by culturing the cells in the presence of cycloheximide for up to 12 hr, only the IgM receptor (which had a higher turnover rate) failed to be expressed. Whereas interaction of IgG immune complex with the IgG receptors was previously shown to induce a modulation of the receptors, contact with antigen-IgM antibody complexes did not alter the mode of expression of IgM receptors.     

La vegetazione delle isole Palmaria e Tino (Golfo della Spezia)

Abstract

The vegetation of the Palmaria and Tino Islands (Gulf of La Spezia). — The vegetation of the Palmaria and Tino islands in the Gulf of La Spezia shows various aspects although they are completely calcareous and do not exceed two hundred meters in height. Along the coast, we have noticed some small beaches with a few psammophytes, and some cliffs vertically overlooking the sea with the endemic Centaurea cineraria var. veneris and with a few shrubs (among which I would like to mention Pinus halepensis) that become bigger and bigger and grow in number with the altitude. On the southern side of Palmaria the Mediterranean « maquis » with Calicotome spinosa, Cistus monspeliensis, Myrtus communis and Pistacia lentiscus is to be noticed. This bush is either compact or rarefied so that it makes a sort of « garigue » on limestone with Euphorbia dendroides, Helichrysum stoechas, Ruta chalepensis, Thymus vulgaris. Owing to the fact that some land strips of Palmaria escaped from fire a thermophilous vegetation is to be found, with a few trees of Pinus halepensis and with a thick undergrowth of Euphorbia dendroides, Cistus incanus, Pistacia lentiscus, Myrtus communis, Smilax aspera. The vegetation of the northern side of Palmaria and Tino is less thermophilous, together with a thick wood of Quercus ilex with some plants of Quercus pubescens and with undergrowth of Viburnum tinus, Smilax aspera, Smilax mauritanica, Coronilla emerus; this wood, especially in the higher part of Palmaria, shows some glades where Erica arborea, Cistus salvifolius, Dorycnium hirsutum grow, with some entities which are distributed quite far from the sea, such as Peucedanum cervaria. Still on the northern side of Palmaria there are some traces of chestnut woods with Castanea sativa, Quercus pubescens, Ostrya carpinifolia, Corylus avellana, Cytisus laburnum and with some plants that usually grow in the cooler areas among the chestnut woods and often in the beech woods like Daphne laureola, Digitalis lutea, Helleborus foetidus and Sesleria autumnalis. A comparison between the biological spectrum of the two islands with the one of Capo Caccia in north western Sardinia and of Marettimo island in western Sicily, clearly shows that in going down southwards, a strong increase of the therophytes (respectively 29,57%, 41,73%, 49,59%), of the chamaephytes and of the nanophanerophytes (13,53%, 16,94%, 18,47%) is to be noticed, while the hemicryptophytes decrease (35,33%, 22,72%, 21,28%). Besides, the vegetation of Capo Caccia although being situated half way between the two Ligurian islands and Marettimo, is much more similar to the latter one; evidently Palmaria and Tino are conditioned by their closeness to the La Spezia coasts while having a climate quite different from them.     

Clerocidin-mediated DNA footprinting discriminates among different G-quadruplex conformations and detects tetraplex folding in a duplex environment

Background

G-quadruplexes are polymorphic non-canonical nucleic acid conformations involved both in physiological and pathological processes. Given the high degree of folding heterogeneity and comparable conformational stabilities, different G-quadruplex forms can occur simultaneously, hence rendering the use of basic instrumental methods for structure determination, like X-ray diffraction or NMR, hardly useful. Footprinting techniques represent valuable and relatively rapid alternative to characterize DNA folding. The natural diterpenoid clerocidin is an alkylating agent that specifically reacts at single-stranded DNA regions, with different mechanisms depending on the exposed nucleotide.

Methods

Clerocidin was used to footprint G-quadruplex structures formed by telomeric and oncogene promoter sequences (c-myc, bcl-2, c-kit2), and by the thrombin binding aptamer.

Results

The easy modulability of CL reactivity towards DNA bases permitted to discriminate fully and partially protected sites, highlights stretched portions of the G-quadruplex conformation, and discriminate among topologies adopted by one sequence in different environmental conditions. Importantly, CL displayed the unique property to allow detection of G-quadruplex folding within a duplex context.

Conclusions

CL is a finely performing new tool to unveil G-quadruplex arrangements in DNA sequences under genomically relevant conditions.

General significance

Nucleic acid G-quadruplex structures are an emerging research field because of the recent indication of their involvement in a series of key biological functions, in particular in regulation of proliferation-associated gene expression. The use of clerocidin as footprinting agent to identify G-quadruplex structures under genomically relevant conditions may allow detection of new G-quadruplex-based regulatory regions.