Interleukin-6 and 12-O-tetradecanoyl phorbol-13-acetate act synergistically in inducing cell-cell separation and migration of human breast carcinoma cells.

Interleukin-6 (IL-6) causes an epithelial to fibroblastoid conversion and an increase in the motility of human ductal breast carcinoma cell lines ZR-75-1 and T-47D. Although IL-6 decreases DNA synthetic activity in these cell lines, the IL-6-induced alterations in cell shape and motility occur independently of inhibition of DNA synthesis per se. Whereas tumor necrosis factor alpha (TNF-alpha) inhibits DNA synthesis in T-47D cells, it does not cause an epithelial-fibroblastoid conversion or other major morphological changes and does not increase cell motility; TNF-alpha rapidly lyses a majority of ZR-75-1 cells. Furthermore, the DNA synthesis inhibitors 5-fluoro-2'-deoxyuridine (FUDR) and methotrexate (MTX) also do not cause effects mimicking the action of IL-6 on cell structure and motility. Transforming growth factors alpha and beta 1, acidic and basic fibroblast growth factors, epidermal growth factor, and insulin-like growth factor-1 (TGF-alpha, TGF-beta 1, aFGF, bFGF, EGF, and IGF-1) have little or no effect on breast cancer cell morphology, which serves to exclude the possibility that the IL-6-induced changes are a consequence of induction of these growth factors by IL-6. 12-O-tetradecanoyl phorbol-13-acetate (TPA) but not 8-bromoadenosine 3',5'-cyclic monophosphate (Br-cAMP) induces changes in the morphology and associative behavior of ZR-75-1 cells that are similar but not identical to those caused by IL-6. The TPA-induced alterations are not blocked by anti-IL-6 neutralizing antibodies; staurosporine inhibits the TPA-induced cell alterations but not those induced by IL-6. IL-6 and TPA used together have a phenotypic effect that greatly exceeds that of either agent alone and results in extensive cell scattering in less than 1 day. These findings are consistent with the hypothesis that IL-6 and TPA induce similar morphological changes and cell scattering via independent pathways.     

Noncontact dipole effects on channel permeation. III. Anomalous proton conductance effects in gramicidin

Proton transport on water wires, of interest for many problems in membrane biology, is analyzed in side-chain analogs of gramicidin A channels. In symmetrical 0.1 N HCl solutions, fluorination of channel Trp(11), Trp-(13), or Trp(15) side chains is found to inhibit proton transport, and replacement of one or more Trps with Phe enhances proton transport, the opposite of the effects on K(+) transport in lecithin bilayers. The current-voltage relations are superlinear, indicating that some membrane field-dependent process is rate limiting. The interfacial dipole effects are usually assumed to affect the rate of cation translocation across the channel. For proton conductance, however, water reorientation after proton translocation is anticipated to be rate limiting. We propose that the findings reported here are most readily interpreted as the result of dipole-dipole interactions between channel waters and polar side chains or lipid headgroups. In particular, if reorientation of the water column begins with the water nearest the channel exit, this hypothesis explains the negative impact of fluorination and the positive impact of headgroup dipole on proton conductance.     

Murine GFP-Mx1 forms nuclear condensates and associates with cytoplasmic intermediate filaments: Novel antiviral activity against VSV

Type I and III interferons induce expression of the “myxovirus resistance proteins” MxA in human cells and its ortholog Mx1 in murine cells. Human MxA forms cytoplasmic structures, whereas murine Mx1 forms nuclear bodies. Whereas both HuMxA and MuMx1 are antiviral toward influenza A virus (FLUAV) (an orthomyxovirus), only HuMxA is considered antiviral toward vesicular stomatitis virus (VSV) (a rhabdovirus). We previously reported that the cytoplasmic human GFP-MxA structures were phase-separated membraneless organelles (“biomolecular condensates”). In the present study, we investigated whether nuclear murine Mx1 structures might also represent phase-separated biomolecular condensates. The transient expression of murine GFP-Mx1 in human Huh7 hepatoma, human Mich-2H6 melanoma, and murine NIH 3T3 cells led to the appearance of Mx1 nuclear bodies. These GFP-MuMx1 nuclear bodies were rapidly disassembled by exposing cells to 1,6-hexanediol (5%, w/v), or to hypotonic buffer (40–50 mosm), consistent with properties of membraneless phase-separated condensates. Fluorescence recovery after photobleaching (FRAP) assays revealed that the GFP-MuMx1 nuclear bodies upon photobleaching showed a slow partial recovery (mobile fraction: ∼18%) suggestive of a gel-like consistency. Surprisingly, expression of GFP-MuMx1 in Huh7 cells also led to the appearance of GFP-MuMx1 in 20–30% of transfected cells in a novel cytoplasmic giantin-based intermediate filament meshwork and in cytoplasmic bodies. Remarkably, Huh7 cells with cytoplasmic murine GFP-MuMx1 filaments, but not those with only nuclear bodies, showed antiviral activity toward VSV. Thus, GFP-MuMx1 nuclear bodies comprised phase-separated condensates. Unexpectedly, GFP-MuMx1 in Huh7 cells also associated with cytoplasmic giantin-based intermediate filaments, and such cells showed antiviral activity toward VSV.     

How to Improve Postgenomic Knowledge Discovery Using Imputation

While microarrays make it feasible to rapidly investigate many complex biological problems, their multistep fabrication has the proclivity for error at every stage. The standard tactic has been to either ignore or regard erroneous gene readings as missing values, though this assumption can exert a major influence upon postgenomic knowledge discovery methods like gene selection and gene regulatory network (GRN) reconstruction. This has been the catalyst for a raft of new flexible imputation algorithms including local least square impute and the recent heuristic collateral missing value imputation, which exploit the biological transactional behaviour of functionally correlated genes to afford accurate missing value estimation. This paper examines the influence of missing value imputation techniques upon postgenomic knowledge inference methods with results for various algorithms consistently corroborating that instead of ignoring missing values, recycling microarray data by flexible and robust imputation can provide substantial performance benefits for subsequent downstream procedures.     

Impaired insulin secretion in the neonatal rhesus monkey after chronic hyperinsulinemia in utero

The secretion of insulin by the pancreas of the newborn rhesus monkey that had been made experimentally hyperinsulinemic in utero was studied in 18 animals. Chronic in utero hyperinsulinemia was produced by the continuous subcutaneous delivery of 4.75 units of insulin per day for 18 +/- 1 days. After delivery, the insulin-containing pump was removed to allow neonatal insulin levels to drop to normal levels. By 6.5 +/- 1.0 hr after pump removal, plasma glucose, insulin, and C-peptide immunoreactivity (CPIR) were comparable in the control and experimental animals. At that point 300 micrograms of glucagon/kg body weight was given iv to stimulate insulin secretion. After 30 min a significant elevation (expressed as the percentage of basal levels) in plasma glucose by 250%, insulin by 200%, and CPIR by 200% was observed in the control animals. In contrast, no changes in plasma insulin or CPIR concentrations occurred, with an attenuated glucose response that was only one-fifth of the control response, in the experimental animals. These results along with the observed lowered concentrations of CPIR in the plasma and insulin in the pancreas at birth can be interpreted as evidence that insulin is an inhibitor of its synthesis and secretion in utero and that this abnormal intrauterine environment causes changes that persist into extrauterine life.     

Vertical transmission of hepatitis B in north India.

A total of 2337 mother-baby paired sera were screened for the presence of hepatitis B surface antigen. Fifty eight mothers (2.48 per cent) were positive for HBsAg. Six babies (10.3 per cent) were positive for HBsAg at birth. The risk of the babies acquiring the infection during the first year of life varied with the serological status of the mothers. In HBeAg positive mothers the babies were at the greatest risk, with 11/15 (73.3 per cent) babies acquiring the infection by twelve months. If the mothers were only HBsAg positive the risk was lower (17.3 per cent), and if the mother was anti-HBe positive also then the baby had the least chance of becoming infected (9 per cent).     

Factors in the rejection and survival of captive cotton top tamarins (Saguinus oedipus)

Captive colonies of cotton top tamarins experience a high rate of rejection of infants within the 1st week of life. The rates of rejection and survival to maturity (2 or more years) among 659 live colony-born infants were correlated with rearing, birth group, litter size, season of birth, gender, origin of parents, experience of parents raising siblings, parity and age of parents, and experience of parent pairs. The most important factors associated with low rejection rates were family life and parental experience raising infants. Infants born into family groups or reared in families were rejected at a significantly lower rate. Rejection of infants whose sires were raised with siblings was significantly lower. Paternal experience was more important than maternal experience. Litter size had no effect on rejection of infants born to family groups, whereas, rejection of triplets was significantly higher than twins or singles among those born to parents alone. Rejection was significantly higher among primiparous births than multiparous birth. The combined experience of colony-born parents was not related to rejection if there were no sibling helpers in the cage at the time of birth. Rejection was significantly lower if sibling helpers were present. High survival of infants who were not rejected was correlated with rearing by or being born into family groups and higher parity and older age of the sires.