The human Ia system: Definition and characterization by xenogeneic antisera

The production of xenogeneic anti-Ia serum against Ia antigens in serum has been previously described in the mouse and we now describe the production of xenogeneic anti-human Ia antisera using similar methods. With an indirect resetting technique, Ia-like antibodies were shown to react with the majority of B cells (95%), a subpopulation of T cells, with carbonyl iron adherent cells, and with some E^–Ig^– null cells, but there was no reaction with red cells and platelets. These reactions were the same as those obtained with DRW antisera using cytotoxicity testing. In addition, antigens detected with xenogeneic antisera were also found in serum, where they were found to exist in a low molecular weight, dialyzable form. By the selective removal of different cell surface markers by cocapping, no association could be found with the specifities detected with the xenogeneic anti-Ia antisera and with surface Ig, ₂-microglobulin, or HLA-A and B specificities. Alloantibodies to DRW specificities (but not HLA-A, B specificities) were able to specifically block the binding of the rabbit anti-Ia antibodies to B cells, and reciprocal blocking of rabbit antisera by DRW antibodies was also observed. Several xenogenic antisera were produced by immunizing rabbits with the serum of different individuals. Each antiserum was shown to contain a number of different specificities, as they gave different reaction patterns with different individuals when testing was done both directly and by absorption. These xenogeneic anti-la sera also segregated in a family with HLA-A and B specificities. The detection of a polymorphic antigenic system segregating with the HLA complex, distinct from HLA-A and B specificities, and whose antigens occur predominantly on B cells is therefore described. Because of the similarity of the reactions of the xenogeneic antisera in man to those found in the mouse, and because of the close relationship to the DRW specificities, the system has been provisionally called the H.Ia system.Abbreviations used in this paper AET 2-aminoethyl isothiouronium bromide - ₂-M -2 microglobulin - BSA Bovine serum albumin - H.Ia Human Ia - HuRBC Human red blood cells - Ig Immunoglobulin - Ir Immune response - MHC Major histocompatibility complex - MLR Mixed lymphocyte reaction - NHS Normal human serum - NMS Normal mouse serum - PBL Peripheral blood lymphocytes - PBS Phosphate-buffered saline - RAHIg Rabbit anti-human immunoglobulin - RASIg Rabbit anti-sheep immunoglobulin - RFC Rosette-forming cells - SAHIg Sheep anti-human immunoglobulin - SARIy Sheep anti-rabbit immunoglobulin - SRBC Sheep red blood cells     

Histochemical Demonstration of Enzyme Activities in Plastic and Paraffin Embedded Tissue Sections

Histochemical staining for enzymes is usually performed on frozen sections. This report lists the longer incubation times required to demonstrate esterase, acid phosphatase, β-galactosidase, and cytochrome oxidase in plastic embedded and routine paraffin embedded tissues. The sections embedded in plastic, i.e. water soluble methacrylate (Polyscience's JB-4) and cut at 2 μm, were far superior to frozen Sections and paraffin embedded sections both in tissue detail and in the localization of the histochemical reaction product.     

Conditions affecting primary cell cultures of functional adult rat hepatocytes

Summary The conditions for obtaining representative, primary adult rat hepatocyte cultures were explored. The methods applied included enzymatic liver perfusion which was nondestructive to hepatocytes, the prevention of aggregation of dissociated cells and the selective attachment of viable cells. These procedures yielded a recovery of 50% of the liver cells which gave rise to cultures representing 14% of the total liver cells. The cultures were composed of homogeneous epithelial-like cells cytologically similar to hepatocytes and possessed a number of liver-specific enzymes. There was virtually no cell division initially and most cells died between 24 and 48 hr. Insulin enhanced the attachment of the liver cells, altered their morphology, but did not prolong cell survival. This study was supported by grant no. BC 133 from the American Cancer Society.     

The effect of osmotic stress on the oxidation of glycolate by the blue-green alga Anacystis nidulans

Planta - Anacystis nidulans Richt. was shown to assimilate glycolic acid, and uptake was light-stimulated. In the dark 90% of the glycolate taken up was oxidised to CO2. Both light and dark uptake...     

The host inflammatory response contributes to disease severity in Crimean-Congo hemorrhagic fever virus infected mice

Crimean-Congo hemorrhagic fever virus (CCHFV) is an important human pathogen. In cell culture, CCHFV is sensed by the cytoplasmic RNA sensor retinoic acid-inducible gene I (RIG-I) molecule and its adaptor molecule mitochondrial antiviral signaling (MAVS) protein. MAVS initiates both type I interferon (IFN-I) and proinflammatory responses. Here, we studied the role MAVS plays in CCHFV infection in mice in both the presence and absence of IFN-I activity. MAVS-deficient mice were not susceptible to CCHFV infection when IFN-I signaling was active and showed no signs of disease. When IFN-I signaling was blocked by antibody, MAVS-deficient mice lost significant weight, but were uniformly protected from lethal disease, whereas all control mice succumbed to infection. Cytokine activity in the infected MAVS-deficient mice was markedly blunted. Subsequent investigation revealed that CCHFV infected mice lacking TNF-α receptor signaling (TNFA-R-deficient), but not IL-6 or IL-1 activity, had more limited liver injury and were largely protected from lethal outcomes. Treatment of mice with an anti-TNF-α neutralizing antibody also conferred partial protection in a post-virus exposure setting. Additionally, we found that a disease causing, but non-lethal strain of CCHFV produced more blunted inflammatory cytokine responses compared to a lethal strain in mice. Our work reveals that MAVS activation and cytokine production both contribute to CCHFV pathogenesis, potentially identifying new therapeutic targets to treat this disease.     

RELATIONSHIP BETWEEN CELL CYCLE AND LIGHT‐LIMITED GROWTH RATE IN OCEANIC PROCHLOROCOCCUS (MIT9312) AND SYNECHOCOCCUS (WH8103) (CYANOBACTERIA)1

The relationships between growth rate, cell‐cycle parameters, and cell size were examined in two unicellular cyanobacteria representative of open‐ocean environments: Prochlorococcus (strain MIT9312) and Synechococcus (strain WH8103). Chromosome replication time, C, was constrained to a fairly narrow range of values (～4–6 h) in both species and did not appear to vary with growth rate. In contrast, the pre‐ and post‐DNA replication periods, B and D, respectively, decreased with increasing growth rate from maxima of ～30 and 10–20 h to minima of ～4–6 and 2–3 h, respectively. The combined duration of the chromosome replication and postreplication periods (C+D), a quantity often used in the estimation of Prochlorococcus in situ growth rates, varied ～2.4‐fold over the range of growth rates examined. This finding suggests that assumptions of invariant C+D may adversely influence Prochlorococcus growth rate estimates. In both strains, cell mass was the greatest in slowly growing cells and decreased 2‐ to 3‐fold over the range of growth rates examined here. Estimated cell mass at the start of replication appeared to decrease with increasing growth rate, indicating that the initiation of chromosome replication in Prochlorococcus and Synechococcus is not a simple function of cell biomass, as suggested previously. Taken together, our results reflect a notable degree of similarity between oceanic Synechococcus and Prochlorococcus strains with respect to their growth‐rate‐specific cell‐cycle characteristics.     

Ecology,morphology and physiology of Chroothece richteriana (Rhodophyta,Stylonematophyceae) in the highly calcareous Río Chícamo,south-east Spain

The ecology of Chroothece was studied in the highly calcareous Río Chícamo, south-east Spain, in order to explain its success there, but rarity elsewhere. The river, which originates mainly from an underground aquifer, has water with high conductivity, sulphate and nitrate but low phosphate concentrations, the latter mainly organic. Chroothece occurs in mats and in lobed colonies reaching 4 cm in the broadest dimension. The colony surface consists of one layer of cells, each of which is attached to a stalk, which dichotomizes when the cell divides; stalks often extend to the colony base. The central region of many mat cells and almost all colony cells has a yellow to orange-brown colour, associated with the numerous lipid droplets densely covering the surface of the pyrenoid and arms of the star-shaped chloroplast. Field material and laboratory isolates indicate that stalk formation occurs under moderate P limitation and both stalks and cell sheath show high phosphatase activities. This also occurred in a culture collection strain maintained for 30 years in a very P-rich medium, but then transferred to a moderately P-limiting medium (c. 0.9 mg l^?1). We suggest that colony formation is initiated by aggregation of motile cells following P pulses in the water. Comparisons are made with Rivularia, a competitor in this nitrate-rich river, in spite of being a N₂-fixer. One difference is that Chroothece cells lie at the periphery of the colonies and are therefore exposed to maximum sunlight, whereas Rivularia trichomes grow inside colonies with photoprotection by scytonemin. However, the ability to withstand heavy grazing pressure may be an especially important factor favouring Rivularia here.     

Complementary genetic and genomic approaches help characterize the linkage group I seed protein QTL in soybean

Background

Cotton fibers (produced by Gossypium species) are the premier natural fibers for textile production. The two tetraploid species, G. barbadense (Gb) and G. hirsutum (Gh), differ significantly in their fiber properties, the former having much longer, finer and stronger fibers that are highly prized. A better understanding of the genetics and underlying biological causes of these differences will aid further improvement of cotton quality through breeding and biotechnology. We evaluated an inter-specific Gh × Gb recombinant inbred line (RIL) population for fiber characteristics in 11 independent experiments under field and glasshouse conditions. Sites were located on 4 continents and 5 countries and some locations were analyzed over multiple years.

Results

The RIL population displayed a large variability for all major fiber traits. QTL analyses were performed on a per-site basis by composite interval mapping. Among the 651 putative QTLs (LOD > 2), 167 had a LOD exceeding permutation based thresholds. Coincidence in QTL location across data sets was assessed for the fiber trait categories strength, elongation, length, length uniformity, fineness/maturity, and color. A meta-analysis of more than a thousand putative QTLs was conducted with MetaQTL software to integrate QTL data from the RIL and 3 backcross populations (from the same parents) and to compare them with the literature. Although the global level of congruence across experiments and populations was generally moderate, the QTL clustering was possible for 30 trait x chromosome combinations (5 traits in 19 different chromosomes) where an effective co-localization of unidirectional (similar sign of additivity) QTLs from at least 5 different data sets was observed. Most consistent meta-clusters were identified for fiber color on chromosomes c6, c8 and c25, fineness on c15, and fiber length on c3.

Conclusions

Meta-analysis provided a reliable means of integrating phenotypic and genetic mapping data across multiple populations and environments for complex fiber traits. The consistent chromosomal regions contributing to fiber quality traits constitute good candidates for the further dissection of the genetic and genomic factors underlying important fiber characteristics, and for marker-assisted selection.