Comparison of transforming growth factor β and a human tumour-derived suppressor factor

Summary Serum-free supernatants from the human melanoma cell line G361 contain a factor that can potently suppress the generation of tumouricidal lymphokine-activated killer (LAK) cells in response to interleukin-2. To characterise the suppressive factor of tumour origin we performed a number of physicochemical and functional comparisons with another immunosuppressive protein, transforming growth factor (TGF). The bioactivity of tumour-derived suppressor factor (TDSF), assayed by suppression of LAK cell generation, was unaffected by a reducing agent but lost when denatured with a chaotropic agent. In contrast, TGF was inactivated by reduction but not denaturation. TDSF lost bioactivity in conditions of pH less than 4, whereas TGF showed no loss of activity. The TDSF moiety has an estimated pI of 4.3 and a molecular mass of 69–87 kDa. This differs from published values of pI 9.5, and 25 kDa molecular mass for TGF. Anti-TGF antiserum reversed the effects of TGF but did not affect the suppression of LAK cell generation caused by TDSF. These findings provide compelling evidence that the TDSF moiety is not TGF, and may be a novel immunoregulatory cytokine.     

Relationship of tumor necrosis factor α expression with activation of sphingomyelinase and lipid peroxidation after removal of cholestatic factor

The goal of this work was to study the expression of tumor necrosis factor α (TNFα), sphingomyelin cycle activation, and lipid peroxidation (LPO) processes after the removal of a cholestatic factor in the liver subjected to different durations of cholestasis. Restored bile flow after a 9-day hepatic cholestasis normalized sphingomyelinase (SMase) activity and levels of TNFα and LPO products. The removal of a cholestatic factor after a 12-day cholestasis did not normalize the studied parameters: SMase activity and the levels of TNFα and LPO products remained much higher compared to control. A significant positive correlation between TNFα expression, SMase activity, and LPO rate has been revealed. The obtained data indicate that hepatocyte apoptosis after bile outflow restoration in late cholestasis can be due to the activation of the sphingomyelin cycle, LPO, and TNFα expression. The synergistic interaction can sharply increase the proapoptotic capacity of each of these factors since TNFα activates SMase and LPO, SMase activity depends on the LPO rate, while ceramide, an SMase-produced secondary messenger of apoptosis, can induce oxidative stress.     

Effect of platelet activating factor on leukocytes II. Enhancement of eosinophil chemotactic factor and β-glucuronidase release

Synthetic 1-O-alkyl-2-O-acetyl-sn-glyceryl-3-phosphorylcholine (PAF) and 1-O-alkyl-sn-glyceryl-3-phosphorylcholine (lyso-PAF) have previously been shown to induce chemotaxis and chemokinesis of human neutrophils. We present here data showing that these agents are inactive by themselves, but that they enhance neutrophil secretion once it has been initiated by a calcium ionosphore or by zymosan. Two substances, the lipid eosinophil chemotactic factor (ECF) and the lysosomal enzyme β-glucuronidase, are used as markers for neutrophil release. PAF augments secretion of both substances in a dose-dependent fashion, with lyso-PAF being less potent. The kinetics of enhancement are very rapid (<2 min) and are not reversible by washing of the cells. A pyrazoline derivative that inhibits arachidonate cyclo-oxygenation and lipoxygenation, reduces the enhancing effect of PAF and lyso-PAF. PAF, and less so lyso-PAF, are thus potentially important modulators of neutrophil secretion during inflammatory processes.     

Expression of scatter factor/hepatocyte growth factor is regionally correlated with the initiation of sperm motility in murine male genital tract: Is scatter factor/hepatocyte growth factor involved in initiation of sperm motility?

Based upon findings that the scatter factor/hepatocyte growth factor (SF/HGF) has strong mitogenic and motogenic properties, and that the sperm cell acquires its fertilizing capacity and motility in the distal parts of mammalian epididymis, the present study was conducted to investigate the role of SF/HGF in initiation of sperm cell motility. This was investigated by determining the expression of SF/HGF in various regions of the murine male genital tract by scatter and cell tracking assays using MDCK epithelial cells, Western blot procedure, and the immunohistochemical procedure using paraffin sections of various regions of the male genital tract. The findings from all these assays indicate that SF/HGF is differentially expressed in various parts of the male genital tract with slight or no expression in the testes, caput epididymis, and vas deferens, and with the highest expression in cauda and corpus (distal) epididymis followed by expression in the corpus (proximal) epididymis. This region-specific SF/HGF expression pattern coincides with the pattern of acquiring the fertilizing capacity and motility by the sperm cell during its transit through the male genital tract. However, wherever SF/HGF was expressed in the male genital tract, its molecular weight was slightly higher (Mr, 82 kD), compared to the SF/HGF expressed in various other somatic tissues (Mr, 78 kD), indicating that the genital tract SF/HGF may be a different molecular species that shares some immunoreactive epitopes with the somatic cell SF/HGF. Incubation of immotile sperm from caput epididymis with the purified human placental SF/HGF of 78 kD initiated motility in 5–15% of sperm population. These results strongly suggest that the SF/HGF-like activity is expressed in the male genital tract in a region-specific manner, and this activity may have a role in initiation of sperm motility acquired during its transit through the epididymis in mammals. © 1994 Wiley-Liss, Inc.     

Properties of the competence-inducing factor of Bacillus subtilis 168I−

It has been shown that the competence-inducing factor of Bacillus subtilis 168I^? exhibits lytic activity toward isolated cell walls and nuclease activity toward transforming DNA. It has been shown that the competence factor covalently bound to CNBr-Sepharose exhibits the same enzymatic properties. A mechanism for the transformation process is proposed which advances the mechanism previously proposed by this laboratory.     

Isolation and characterization of autoagglutination factor of Yersinia pestis Hms− cells

An approach for isolation of an autoagglutination factor (AF) from Hms(-) cells of the plague agent has been developed. Purified AF has been obtained and characterized in physicochemical properties. The AF is found to be a complex of a 17.5-kD protein with a low molecular weight peptide component, which binds iron ions and shows siderophore activity. This low molecular weight component is responsible for hydrophobic properties and immunochemical activity of the AF, as well as for its ability to interact with the plague diagnosticum L-413c bacteriophage.     

What factor drives the fibrillogenic association of beta-sheets?

The identification of the driving factor for fibril formation is paramount to understand the molecular basis of amyloidogenic disease. Recently, an atomic-detail structure of a fibrillogenic aggregate was reported and revealed a tight packing of beta-sheets. However, there is not a single pair-wise interaction of significance between the beta-sheets, no hydrogen bond and no hydrophobic interaction. Instead, there is extensive burial of polar groups at the interface. These observations lead to the question: What factor drives the association of beta-sheets? This issue is addressed by combining all-atom molecular dynamics with an implicit-solvent analysis. The driving force for the association arises from the mechanical equivalent of the dehydration propensity of pre-formed intra-sheet hydrogen bonds and dipole-dipole interactions.     

Host factor requirements and some properties of ΦXtB

Summary Replication of XtB, a capsid mutant of bacteriophage X174, depends on the host functions directed by the E. coli genes dnaE, dnaF, dnaG, dnaZ, lig and rep. The cellular products of dnaA, dnaB, dnaC(D), dnaI, dnaP, polA, polB and xth genes are, however, dispensable for the viral growth. In these host factor requirements, XtB resembles phages K and St-1, rather than X174. Host ranges of XtB, St-1 and K overlap considerably, and growth temperature of the three phages is somewhat higher than that of X174. Furthermore, XtB is, like K, inactivated by antiserum against St-1. XtB may thus fill an evolutionary gap between the X174 group and the St-1 group.     

Effect of anticalmodulin drugs on the action of yeast α factor pheromone

Saccharomyces cerevisiae factor pheromone arrest growth of cells of the a mating type (MAT a) at the G1 phase of the cell cycle. When treatment of MAT a cells with factor was carried out in the presence of anticalmodulin drugs, trifluoperazine or chlorpromazine, the extent of cell growth arrest induced by factor was reduced or even became undetectable. These results lend support to the hypothesis that calmodulin plays a role as mediator in the action of factor on MAT a cells.Abbreviation MAT mating type     

Tumor necrosis factor α knockout increases fertility of mice

Tumor necrosis factor α (TNFα) acts through two receptors, TNFα receptor| (TNFR|) and TNFα‖ (TNFR‖). Tumor necrosis factor α receptor| knockout mice had early senescence and poor fertility, whereas TNFR‖ knockout mice had reproductive performance not different from wild type (WT) mice. In the present study, TNFα knockout mice were used to study the roles of TNFα in female reproduction. The TNFα−/− mice had similar vaginal opening time (PD 27.6 ± 1.8 vs PD 27.7 ± 1.9, respectively, P > 0.05) and exogenous gonadotropin primed TNFα−/− mice shed more ova (28.9 ± 3.75 vs 9.8 ± 0.51, respectively, P = 0.001) compared with WT controls. At 2 mo of age, in 21 d, TNFα−/− mice had more estrous cycles than WT counterparts (6.0 ± 0.25 vs 4.0 ± 0.28, respectively, P < 0.05). Tumor necrosis factor α mutation also influenced ovarian follicular development; TNFα−/− mice had approximately a two-fold larger follicle pool in the early neonatal period (6087 ± 508.15 vs 3440 ± 261.91, respectively, P = 0.004), whereas TNFα knockout affected growth of primordial follicles to the antral stage as well. Moreover, TNFα−/− mice gave birth to 21% more pups than control mice during a 12 mo breeding period (37.38 ± 3.69 vs 22.38 ± 3.53, respectively, P = 0.03). At 1 y of age, the follicular reserve in TNFα−/− mice was more than that in WT mice. These physiological differences in TNFα−/− mice were associated with increased proliferation of granulosa cells and decreased apoptosis of oocytes. This was apparently the first demonstration that in the TNFα−/− mouse model, multiple parameters of ovarian function were altered, and that lack of TNFα increased fertility in mice.     

α-Enolase, an adhesion-related factor of Mycoplasma bovis

Mycoplasma bovis is the causative agent of Mycoplasma bovis-associated disease (MbAD). Although the mechanisms underlying M. bovis adherence to host cells is not clear, recent studies have shown that the cell surface protein α-enolase facilitates bacterial invasion and dissemination in the infected host. In this study, we cloned, expressed and purified recombinant M. bovis α-enolase and induced polyclonal anti-α-enolase antibodies in rabbits. M. bovis α-enolase was detected in the cytoplasmic and membrane protein fractions by these antibodies. Triple immunofluorescence labeling combined with confocal laser scanning microscopy (CLSM) revealed that the plasminogen (Plg) enhanced the adherence of M. bovis to embryonic bovine lung (EBL) cells; the values obtained for adherence and inhibition are consistent with this finding. Interestingly, we found that trace amounts of trypsin acted as a more effective enhancer of cell adherence than Plg. Hence, our data indicate that surface-associated M. bovis α-enolase is an adhesion-related factor of M. bovis that contributes to adherence by binding Plg.     

Enhancement of epidermal growth factor receptor expression on glioma cells by recombinant tumor necrosis factor α

Summary Recombinant tumor necrosis factor (rTNF; optimal dose 1000 U/ml) significantly increased the density of epidermal growth factor receptor (EGF-R) in three of four glioma cell lines in culture as determined by binding analysis of anti-EGF-R monoclonal antibody (mAb) 425. Since enhancement of EGF-R expression by rTNF- was inhibited when cells were treated with the protein synthesis inhibitor cycloheximide, the effects of rTNF may be protein-synthesis-dependent. The dose of rTNF that was optimal for up-regulation of EGF-R on glioma cells did not inhibit the growth of these cells.¹²⁵I-labeled mAb 425 lysed glioma cells in culture following its internalization into the cells. After glioma cells had been treated with rTNF, the growth-inhibitory effects of the mAb were significantly enhanced, probably a reflection of the increase in EGF-R density on the tumor cell surfaces. The rTNF effects were specific to the EGF-R and did not affect unrelated glioma-associated antigens. In our previous clinical trials,¹²⁵I-labeled mAb 425 showed immunotherapeutic effects in glioma patients. The present study provides the basis for considerations of combined immunotherapy of glioma patients with¹²⁵I-labeled mAb 425 and rTNF.     

Impact factor of Revista Iberoamericana de Micología

The impact factor is a bibliometric indicator published annually in the Journal Citation Reports, and widely regarded as a quality ranking of the journals included in this database. The problem with this indicator is that the impact factor of several journals not listed in the Science Citation Index database is largely unknown. The aim of this study was to analyze the 2001 national and international impact factor of Revista Iberoamericana de Micología. The National impact factor of Revista Iberoamericana de Micología was obtained by adding the number of cites in 2001 from a total of 87 Spanish medical journals of greater scientific quality. Also, bibliographical references from Spanish journals indexed in the 2001 Journal Citation reports database have been included to determine the international impact factor of this analyzed journal. Revista Iberoamericana de Micología received a total of 62 cites from published articles in 1999 to 2001, coming from 20 different journals, being their self-citation index 10.1%. The journal with the highest number of cites to Revista Iberoamericana de Micología was Journal of Clinical Microbiology, with 12 cites (19.3%). According to this findings the national and international impact factor of Revista Iberoamericana de Micología was 0.266 and 0.606, respectively. The impact factor of Revista Iberoamericana de Micología, although not included in the Science Citation Index database, was higher than other Journal Citation Reports. Moreover, Revista Iberoamericana de Micología received most of its citations from high impact factor journals included in the Journal Citation Reports database. These data support the international recognition of the scientific level of the journal.