The lethal effects of gamma irradiation on larvae of the Huhu beetle, Prionoplus reticularis: a potential quarantine treatment for New Zealand export pine trees

Gamma irradiation was investigated as a possible method for disinfestation of huhu beetle larvae, Prionoplus reticularis White, in Pinus radiataD. Don. Larvae of four representative size classes were irradiated at six doses, and the lethal dose (LD₉₉) calculated from mortality data 3 days and 10 days post treatment. All larval size classes showed a similar sensitivity to gamma irradiation and required 3677 Gray (Gy) and 2476 Gy for a LD₉₉ 3 and 10 days post-treatment, respectively. The penetration of gamma irradiation into pine wood was found to be lowest in freshly cut logs, and decreased linearly at a rate of 0.698 Gy mm^–1 of wood. The penetration was greatest in wood that had been stored for 2 years, and decreased 0.512 Gy mm^–1 of wood. These results are likely to be correlated with wood moisture content. Gamma irradiation appears to be a potential alternative method to fumigation for quarantine treatment of P. reticularis.     

Use of an inhibitor to identify members of the hormone-sensitive lipase family

Hormone-sensitive lipase (HSL) contributes importantly to the mobilization of fatty acids from the triacylglycerols stored in adipocytes, which provide the main source of energy in mammals. On the basis of amino acid sequence alignments and three-dimensional structures, this enzyme was previously found to be a suitable template for defining a family of serine carboxylester hydrolases. In this study, the HSL family members are characterized rather on the basis of their inhibition by 5-methoxy-3-(4-phenoxyphenyl)-3H-[1,3,4]oxadiazol-2-one (compound 7600). This compound inhibits mammalian HSL as well as other HSL family members, such as EST2 from the thermophilic eubacterium Alicyclobacillus acidocaldarius and AFEST from the hyperthermophilic archaeon Archaeoglobus fulgidus. Various carboxylester hydrolases that are not members of the HSL family were found not to be inhibited by compound 7600 under the same experimental conditions. These include nonlipolytic hydrolases such as Torpedo californica acetylcholinesterase and pig liver esterase, as well as lipolytic hydrolases such as human pancreatic lipase, dog gastric lipase, Thermomyces lanuginosus lipase, and Bacillus subtilis LipA. When vinyl esters were used as substrates, the residual activity of HSL, AFEST, and EST2 decreased with an increase in compound 7600 concentration in the incubation mixture. The inhibitor concentration at which the enzyme activity decreased to 50% after incubation for 5 min was 70, 20, and 15 nM with HSL, AFEST, and EST2, respectively. Treating EST2 and AFEST with the inhibitor resulted in an increase in the molecular mass, as established by performing matrix-assisted laser desorption ionization time-of-flight mass spectrometry analysis. This increase in the molecular mass, which corresponds approximately to the molecular mass of the inhibitor, indicates that a covalent enzyme-inhibitor complex has been formed. Surface-enhanced laser desorption ionization time-of-flight mass spectrometry analysis of a trypsin digest of AFEST treated with the inhibitor or not treated showed the occurrence of an increase in the molecular masses of the "GESAGG"-containing peptide, which is compatible with the formation of a covalent complex with the inhibitor.     

Molecular cloning and expression of major structural protein VP1 of the human polyomavirus JC virus: formation of virus-like particles useful for immunological and therapeutic studies

The major structural viral protein, VP1, of the human polyomavirus JC virus (JCV), the causative agent of progressive multifocal leukoencephalopathy (PML), was expressed by using recombinant baculoviruses. Recombinant VP1 formed virus-like particles (VLP) with the typical morphology of empty JCV capsids. Purified VP1 VLP bind to SVG, B, and T cells, as well as to monkey kidney cells. After binding, VP1 VLP were also internalized with high efficiency and transported to the nucleus. Immunization studies revealed these particles as highly immunogenic when administered with adjuvant, while immunization without adjuvant induced no immune response. VP1 VLP hyperimmune serum inhibits binding to SVG cells and neutralizes natural JCV. Furthermore, the potential of VP1 VLP as an efficient transporter system for gene therapy was demonstrated. Exogenous DNA could be efficiently packaged into VP1 VLP, and the packaged DNA was transferred into COS-7 cells as shown by the expression of a marker gene. Thus, VP1 VLP are useful for PML vaccine development and represent a potential new transporter system for human gene therapy.     

Long-term platinum retention after treatment with cisplatin and oxaliplatin

Background  

The aim of this study was to evaluate long-term platinum retention in patients treated with cisplatin and oxaliplatin.     

Reactivation of human immunodeficiency virus type 2 in macaques after simian immunodeficiency virus SIVmac superinfection.

By superinfection of human immunodeficiency virus type 2 (HIV-2) strain HIV-2ben-infected macaques with simian immunodeficiency virus (SIV) strain SIVmac, we investigated the mutual influences of an apathogenic and a pathogenic virus in vivo. Four rhesus and two cynomolgus monkeys were infected with HIV-2ben in 1988 and 1989, respectively. Virus could be reisolated from five of six animals 6 weeks after infection. The monkeys remained healthy over the next 2 to 3 years. PCR for viral RNA became negative, and virus could no longer be reisolated by coculture. All six macaques were superinfected with the pathogenic SIVmac251/32H. Subsequently, five monkeys became persistently viremic, while one animal was protected against the SIVmac infection. In the peripheral blood mononuclear cells and cocultures of the five viremic animals, DNA from both HIV-2 and SIVmac was present. The plasma contained RNA from both viruses. Thus, superinfection with SIVmac activated HIV-2. A proliferative T-cell response against both HIV-2 and SIVmac was measured in all animals after superinfection. Such a response was regularly seen after infection with the apathogenic HIV-2 but never when the pathogenic SIVmac alone was administered. While naive control monkeys inoculated with SIVmac251/32H regularly develop AIDS-like symptoms soon after infection and have to be killed, none of the preinfected animals has developed AIDS-like symptoms, but two of six animals developed tumors. After the SIVmac challenge, however, apoptotic lymphocytes were detected in the peripheral blood mononuclear cells of all animals. Thus, the presence of an apathogenic viral variant seems to retard the disease occurring after infection with a pathogenic virus rather than to confirm total protection. This partial protection appears to depend on a specific proliferative T-cell response early after infection.     

Efficacy and deficiencies of rapid biomonitoring in biodiversity conservation: a case study in South Africa

Rapid biomonitoring protocols, using biotic indices based on macroinvertebrate diversity to assess river ecosystem health, are widely used globally. Such quick assessment techniques are lauded for the rapid results obtained and the relatively easy protocol used to achieve an answer. However, do such quick assessments of water quality give enough information about ecosystems? Are important details being overlooked? When should a full faunal survey be used in preference? Important research programmes, including environmental impact studies, often misuse biomonitoring techniques, making influential management decisions using superficial, low-level data obtained using biomonitoring tools, inappropriate to address those management objectives. The value of using biomonitoring as a quick tool, versus a more detailed faunal assessment, is considered here. The assessment of teloganodid mayfly fauna occurring in South African rivers provides an example of the value of detailed studies versus superficial family level investigations, showing that a rapid biomonitoring approach should not be used as a shortcut when a more detailed survey is needed. Each situation should be assessed for its own merit in a given set of project circumstances. A checklist of criteria is presented, giving guidance on when rapid biomonitoring alone is valuable and when more detailed assessments would give a more relevant result.     

The effect of the "patency test" on arterial endothelial surface

The effect of the "milking patency test" on the arterial endothelium of the experimental rat is investigated. Each of 18 rats served as its own control. Bilateral femoral artery anastomoses were performed in identical fashion. The milking patency test was performed on one side (experimental) but not on the other (control). After removal of the approximator clamps, rats were perfusion-fixed in situ. Harvested experimental vessels stained with silver showed a twofold increase in endothelial cell loss compared to controls. Visual evidence of extensive endothelial loss was seen on silver-stained segments in the tested area. This was corroborated by scanning electron microscopy. The degree of damage seen in this study suggests that the milking patency test is too traumatic for use in clinical microsurgery.