Sulfated derivatives of Escherichia coli K5 polysaccharides as modulators of fibroblast growth factor signaling

Heparan sulfate (HS) proteoglycans are intimately involved in the regulation of fibroblast growth factor (FGF) signaling. HS and the related glycosaminoglycan heparin interact with FGFs and FGF receptors (FGFRs), and it is believed that both interactions are required for productive FGF signaling. Attempts to inhibit FGF activity have been made with modified heparin preparations, various heparin-like polysaccharide analogues and other polyanionic molecules, which may all act by interfering with the physiological HS-FGF-FGFR interactions on the cell surface. Here, we have studied the potential of sulfated derivatives of a bacterial polysaccharide (capsular polysaccharide from Escherichia coli K5 (K5PS)) in the modulation of FGF-heparin/HS interactions and FGF signaling. We demonstrate that O-sulfated and N,O-sulfated species of K5PS, with high degrees of sulfation, displaced FGF-1, FGF-2, and FGF-8b from heparin. However, only O-sulfated K5PS efficiently inhibited the FGF-induced proliferation of S115 mammary carcinoma cells and 3T3 fibroblasts, whereas N,O-sulfated K5PS had little or no inhibitory effect. Studies with CHO677 cells lacking endogenous HS, as well as with chlorate-treated S115 cells expressing undersulfated HS, indicated that whereas exogenously administered heparin and N,O-sulfated K5PS restored the cellular response toward FGF stimulation, O-sulfated K5PS was largely devoid of such stimulatory activity. Our data suggest that highly O-sulfated species of K5PS may be efficient inhibitors of FGF signaling.     

Immunocytochemical demonstration of 5-HT-like and FMRF-amide-like substances in whole mounts of Microstomum lineare (Turbellaria)

Summary A whole mount immunofluorescence method is used for an investigation of immunoreactivity (IR) to anti-(a-) 5-HT and anti-(a-)FMRF-amide in the nervous system (NS) of Microstomum lineare (Turbellaria, Macrostomida, Platyhelminthes). New details of the organization of the NS are demonstrated, differences in 5-HT and FMRF amide IR are revealed, and new information on the development of the NS in zooids is obtained. In contrast to previous reports of a reduction (one pair of nerve cords without transverse processes) of the basic turbellarian plan, IR to both antisera reveals three pairs of longitudinal nerve cords, and features of the orthogonal organization, characterized by transverse commissures. The lateral pair of nerve cords is the most prominent. The following differences in the patterns of 5-HT and FMRF-amide IR are observed: 1. Perikarya positive for a-5-HT and a-FMRF-amide in the brain show different localizations. 2. Perikarya positive for a-5HT occur along the main lateral nerve cords, while the cords visualized by FMRF-amide IR look double-stranded and lack associated perikarya. 3. 5-HT IR is observed in a postpharyngeal commissure, which is absent in the a FMRF-amide-stained preparations. 4. In developing zooids 5-HT IR is first observed in the postpharyngeal commissure and later on in an increasing number of perikarya and in the neuropile. The first FMRF-amide IR in developing zooids appears in the cerebral commissure and in two perikarya in front of this commissure.     

Proliferative T-cell response to HIV envelope glycoprotein in immunized and infected primates and human beings

Human immunodeficiency virus (HIV)-specific helper T-cell response was studied in human subjects and nonhuman primates either infected with HIV or immunized with different HIV protein preparations. A strong group-specific T-cell response involving T-cell proliferation and lymphokine secretion was observed in immunized chimpanzees and rhesus monkeys as well as HIV-infected chimpanzees and gibbons. HIV-infected people demonstrated a low or no HIV-specific T-cell response. In contrast, five of 14 HIV antibody-negative sexual partners of HIV-infected men recognized one or more T-cell epitopes in the envelope glycoprotein of HIV.     

Uukuniemi virus contains an RNA polymerase.

An RNA-dependent RNA polymerase activity has been found associated with Uukuniemi virions. The enzyme activity is expressed only after disrupting the virions with the nonionic detergent Triton X-100 and is absolutely dependent on Mn2+, whereas Mg2+ is not required, a finding that distinguishes this polymerase from those of other enveloped minus-strand RNA viruses. Within the range pH 7.2 to 8.5 no distinct optimum was found. The optimum temperature was between 37 and 40 C. The reaction was not inhibited by actinomycin D, rifampin, or DNase, whereas RNase was completely inhibitory. The partially RNase-resistant product consisted of rather small-sized RNA, which contained sequences complementary to Uukuniemi virus RNA as shown by hybridization to the template L, M, and S RNA species of Uukuniemi virus.     

Selective responses of mouse T lymphocytes to different T mitogens and in mixed lymphocyte culture induced cytolysis reaction.

CBA spleen T lymphocytes were stimulated by the T mitogens concanavalin-A (Con-A), phytohemagglutinin (PHA), and leukoagglutinin (LA). On the 2nd to 3rd culture day the activated cells (blasts) were separated from the nonactivated cells (lymphocytes) by 1g velocity sedimentation. The lymphocytes which were not activated during the primary culture (lymphocyte fraction from the velocity sedimentation) were then stimulated by the same mitogens or in one-way MLC to DBA/2 m, and tested for relevant target lysis after MLC stimulation. Primary stimulation with Con-A abolished the responses to Con-A, to PHA, and to LA, whereas primary stimulation with PHA or with LA abolished the responses to these mitogens but left behind a considerable Con-A response. Stimulation with any one of the listed T mitogens did not significantly affect the MLC responses. While primary stimulation with Con-A abolished the relevant target cell lysis after MLC stimulation, primary stimulation with PHA or with LA reduced it only slightly. Assuming that the various mitogens stimulate separate subpopulations of T cells, the results seem to indicate that the Con-A-responsive population includes the PHA- and LA-responsive populations but not the MLC-responsive population. It also appears that the T cells generated to killer cells during MLC are mainly confined to the concanavalin-responsive population.     

Post-drainage changes in vegetation composition and carbon balance in Lakkasuo mire,Central Finland

The post-drainage changes in vegetation composition and carbon balance were studied on four site types (from minero- to ombrotrophic conditions) in Lakkasuo mire, central Finland, by directly comparing undrained and drained parts (30 years ago) of the mire. Drainage had drastically changed the species composition of the sites, especially at the minerotrophic sites, where almost all Sphagna had been replaced by forest mosses. On the ombrotrophic sites much of the mire vegetation still remained 30 years after drainage. Drainage had decreased the C stores in ground vegetation on the minerotrophic sites but increased them on the ombrotrophic sites. The changes were, however, very small compared to the changes in the tree stand, where the C stores had increased at all sites (increasing with nutrient level). The change in peat C balance over the 30-year post-drainage period was negative on the most nutrient-rich site, and positive on the others, increasing with lower nutrient levels. The decrease in the peat C balance on the most nutrient-rich site was compensated by the greater increase in the tree stand C stores and the changes in the total C balance (peat+tree stand+ground vegetation) remained positive on all sites. This revised version was published online in June 2006 with corrections to the Cover Date.     

Current growth,fat reserves and somatic condition of juvenile Baltic herring (<Emphasis Type="Italic">Clupea harengus membras</Emphasis>) reared in different salinities

We studied the effect of salinity on growth, fat reserves and condition of the Baltic herring (Clupea harengus membras) juveniles in order to determine their optimum salinity. About 5 months old fish were reared in four salinities (5.7, 8, 12 and 15 psu) over a period of 1.5 months in constant temperature (+6°C) and photoperiod (light:dark = 12 h:12 h). Uptake of radioactively labelled glycine (¹⁴C-glycine) by the scales was used as an indicator of growth rate. The amount of mesenteric fat varied among individuals, but fish kept in 12 psu had significantly more fat in their body cavity and also their somatic condition was better (P < 0.05) than in juveniles kept in the other salinities. Incorporation of ¹⁴C-glycine by the scales was dependent not only on salinity, but also on the method of scale sampling. Part of the scales sampled was non-growing and therefore unsuitable for the analysis of growth. Using the growing scales in the analysis, the current growth rate of herring juveniles was highest in salinities of 8 and 12 psu. Fat reserves, somatic condition and growth rate suggested that Baltic herring juveniles have their optimum salinity in 8–12 psu, which is somewhat higher than the salinity in most of the nursery grounds in the Baltic Sea.