Regulation of synthesis and activity of NAD(+)-dependent 15-hydroxy-prostaglandin dehydrogenase (15-PGDH) by dexamethasone and phorbol ester in human erythroleukemia (HEL) cells

Dexamethasone stimulated 15-PGDH activity in HEL cells in a time and concentration dependent manner. Increase in 15-PGDH activity by dexamethasone was found to be accompanied by an increase in enzyme synthesis as revealed by Western blot and [35S]methionine labeling studies. In addition to dexamethasone, other anti-inflammatory steroids also increased 15-PGDH activity in the order of their glucocorticoid activity. Among sex steroids only progesterone increased significantly 15-PGDH activity. 12-0-Tetradecanoylphorbol-13-acetate (TPA) also induced the synthesis of 15-PGDH but inhibited the enzyme activity. It appears that TPA caused a time dependent inactivation of 15-PGDH by a protein kinase C mediated mechanism.     

Revisiting the use of Iprodione and Trichoderma in the integrated management of onion white rot

The biocontrol properties of Trichoderma species are well documented, but their effectiveness in antagonism of the problematic Sclerotium cepivorum, the causal agent of white rot in Allium species, appears limited with reports of significant control only relating to deliberately-mutated strains of Trichoderma. Our previous studies have indicated the possibility of using selected naturally-occurring strains of the antagonist in the suppression of other diseases; now in vitro and controlled environment in vivo studies have indicated that a degree of control of Onion White Rot is possible, and that the selected antagonist strains can be used in integrated treatments with Iprodione to good effect. The possible value of such treatments is considered in light of other approaches to the suppression of this continuing problem.     

A web server to locate periodicities in a sequence

Summary : FT is a tool written in C++, which implements the Fourier analysis method to locate periodicities in aminoacid or DNA sequences. It is provided for free public use on a WWW server with a Java interface. Availability : The server address is http://o2.db. uoa.gr/FT Contact : shamodr@atlas.uoa.gr      

Improving performance of HVAC systems to reduce exposure to aerosolized infectious agents in buildings; recommendations to reduce risks posed by biological attacks

The prospect of biological attacks is a growing strategic threat. Covert aerosol attacks inside a building are of particular concern. In the summer of 2005, the Center for Biosecurity of the University of Pittsburgh Medical Center convened a Working Group to determine what steps could be taken to reduce the risk of exposure of building occupants after an aerosol release of a biological weapon. The Working Group was composed of subject matter experts in air filtration, building ventilation and pressurization, air conditioning and air distribution, biosecurity, building design and operation, building decontamination and restoration, economics, medicine, public health, and public policy. The group focused on functions of the heating, ventilation, and air conditioning systems in commercial or public buildings that could reduce the risk of exposure to deleterious aerosols following biological attacks. The Working Group's recommendations for building owners are based on the use of currently available, off-the-shelf technologies. These recommendations are modest in expense and could be implemented immediately. It is also the Working Group's judgment that the commitment and stewardship of a lead government agency is essential to secure the necessary financial and human resources and to plan and build a comprehensive, effective program to reduce exposure to aerosolized infectious agents in buildings.     

A novel reagentless sensing system for measuring glucose based on the galactose/glucose-binding protein.

The galactose/glucose-binding protein (GBP) is synthesized in the cytoplasm of Escherichia coli in a precursor form and exported into the periplasmic space upon cleavage of a 23-amino-acid leader sequence. GBP binds galactose and glucose in a highly specific manner. The ligand induces a hinge motion in GBP and the resultant protein conformational change constitutes the basis of the sensing system. The mglB gene, which codes for GBP, was isolated from the chromosome of E. coli using the polymerase chain reaction (PCR). Since wild-type GBP lacks cysteines in its structure, introducing this amino acid by site-directed mutagenesis ensures single-label attachment at specific sites with a sulfhydro-specific fluorescent probe. Site-directed mutagenesis by overlap extension PCR was performed to prepare three different mutants to introduce a single cysteine residue at positions 148, 152, and 182. Since these residues are not involved in ligand binding and since they are located at the edge of the binding cleft, they experience a significant change in environment upon binding of galactose or glucose. The sensing system strategy is based on the fluorescence changes of the probe as the protein undergoes a structural change on binding. In this work a reagentless sensing system has been rationally designed that can detect submicromolar concentrations of glucose. The calibration plots have a linear working range of three orders of magnitude. Although the system can sense galactose as well, this epimer is not a potential interfering substance since its concentration in blood is negligible.     

Relative hypoglycemia and hyperinsulinemia in mice with heterozygous lipoprotein lipase (LPL) deficiency. Islet LPL regulates insulin secretion.

Lipoprotein lipase (LPL) provides tissues with fatty acids, which have complex effects on glucose utilization and insulin secretion. To determine if LPL has direct effects on glucose metabolism, we studied mice with heterozygous LPL deficiency (LPL+/-). LPL+/- mice had mean fasting glucose values that were up to 39 mg/dl lower than LPL+/+ littermates. Despite having lower glucose levels, LPL+/- mice had fasting insulin levels that were twice those of +/+ mice. Hyperinsulinemic clamp experiments showed no effect of genotype on basal or insulin-stimulated glucose utilization. LPL message was detected in mouse islets, INS-1 cells (a rat insulinoma cell line), and human islets. LPL enzyme activity was detected in the media from both mouse and human islets incubated in vitro. In mice, +/- islets expressed half the enzyme activity of +/+ islets. Islets isolated from +/+ mice secreted less insulin in vitro than +/- and -/- islets, suggesting that LPL suppresses insulin secretion. To test this notion directly, LPL enzyme activity was manipulated in INS-1 cells. INS-1 cells treated with an adeno-associated virus expressing human LPL had more LPL enzyme activity and secreted less insulin than adeno-associated virus-beta-galactosidase-treated cells. INS-1 cells transfected with an antisense LPL oligonucleotide had less LPL enzyme activity and secreted more insulin than cells transfected with a control oligonucleotide. These data suggest that islet LPL is a novel regulator of insulin secretion. They further suggest that genetically determined levels of LPL play a role in establishing glucose levels in mice.     

Photo-identification and satellite telemetry connect southern right whales from South Georgia Island (Islas Georgias del Sur) with multiple feeding and calving grounds in the southwest Atlantic

The sub-Antarctic waters of South Georgia Island (Islas Georgias del Sur, SG/IG) are a regularly visited feeding ground for southern right whales (Eubalaena australis, SRW) in the southwest Atlantic. Satellite telemetry and photo-identification records were compared to better understand the role of SG/IG in the SRW migratory network. We present the first insights from SRW satellite-tracked from the SG/IG feeding ground, habitat use patterns in the Scotia Arc, and movements to Antarctic habitats. Photo-identification comparisons to calving and feeding areas across the South Atlantic and a review of sightings of cetaceans reported from Bird Island (west of SG/IG) since 1979 illuminate long-term habitat use patterns in SG/IG. We present the first recorded migratory movement between SG/IG and multiple countries: Argentina, Uruguay, and Brazil. Photo-identification (1) linked SG/IG to a female SRW with a long-term sighting history in Brazil, and (2) provided the first match between SG/IG and the western Antarctic Peninsula, suggesting the latter could extend the feeding area for southwest Atlantic SRW. Satellite tracking and opportunistic sightings suggest that shelf and coastal waters west of SG/IG represent an important multi-season SRW feeding habitat and add to our overall understanding of habitats and ranges occupied by recovering southwest Atlantic SRW.     

Targeted overactivity of beta cell K(ATP) channels induces profound neonatal diabetes

A paradigm for control of insulin secretion is that glucose metabolism elevates cytoplasmic [ATP]/[ADP] in beta cells, closing K(ATP) channels and causing depolarization, Ca2+ entry, and insulin release. Decreased responsiveness of K(ATP) channels to elevated [ATP]/[ADP] should therefore lead to decreased insulin secretion and diabetes. To test this critical prediction, we generated transgenic mice expressing beta cell K(ATP) channels with reduced ATP sensitivity. Animals develop severe hyperglycemia, hypoinsulinemia, and ketoacidosis within 2 days and typically die within 5. Nevertheless, islet morphology, insulin localization, and alpha and beta cell distributions were normal (before day 3), pointing to reduced insulin secretion as causal. The data indicate that normal K(ATP) channel activity is critical for maintenance of euglycemia and that overactivity can cause diabetes by inhibiting insulin secretion.