No evidence of substantial nicotine metabolism by Lasioderma serricorne (Fabricius) (Coleoptera: Anobiidae) reared on tobacco

The cigarette beetle, Lasioderma serricorne (Fabricius), is the most prevalent pest of stored tobacco and is responsible for substantial economic damage. Other than L. serricorne, few insects have been found to infest tobacco due to its low nutritional value and nicotine toxicity. Self, L.S., Guthrie, F.E., Hodgson, E. [1964a. Metabolism of nicotine by tobacco-feeding insects. Nature 204, 300-301] reported that L. serricorne metabolizes at least 70% of ingested nicotine to cotinine. This study re-examined nicotine metabolism by the L. serricorne using gas chromatography/flame ionization detection (GC/FID) and gas chromatography/thermal desorption with time-of-flight mass spectrometry (GC/TDS/ToF). Cigarette beetles reared on whole-wheat flour were compared with those reared on tobacco. Larvae, depurated larvae, frass, and both diets were analyzed to determine if nicotine was assimilated, sequestered, metabolized, and/or excreted. Contrary to previous findings, these data indicate that L. serricorne does not metabolize a significant amount of nicotine into cotinine. Nicotine is excreted unmodified. Older research involving nicotine metabolism by other insects should be reviewed in the light of these findings.     

Expression of CD38 increases intracellular calcium concentration and reduces doubling time in HeLa and 3T3 cells

CD38 is a bifunctional ectoenzyme, predominantly expressed on hematopoietic cells during differentiation, that catalyzes the synthesis (cyclase) and the degradation (hydrolase) of cyclic ADP-ribose (cADPR), a powerful calcium mobilizer from intracellular stores. Due to the well established role of calcium levels in the regulation of apoptosis, proliferation, and differentiation, the CD38/cADPR system seems to be a likely candidate involved in the control of these fundamental processes. The ectocellular localization of the cyclase activity, however, contrasts with the intracellular site of action of cADPR. Here we demonstrate that ectocellular expression of human CD38 in CD38(-) HeLa and 3T3 cells results in intracellular CD38 substrate (NAD+ + NADH) consumption and product (cADPR) accumulation. Furthermore, a causal relationship is established between presence of intracellular cADPR, partial depletion of thapsigargin-sensitive calcium stores, increase in basal free cytoplasmic calcium concentration, and decrease of cell doubling time. The significant shortening of the S phase in CD38(+) HeLa cells, as compared with controls, demonstrates an effect of intracellular cADPR on the mammalian cell cycle.     

Esophageal intramural pseudodiverticulosis

Cows that develop a persistent lymphocytosis (PL) as a result of bovine leukemia virus (BLV) infection develop massive proliferation of B-lymphocytes expressing both IgM and CD5 markers. The association of these two markers on peripheral blood mononuclear cells (PBMC) derived from BLV-infected cows and also expressing BLV-gp51 antigen marker on these cells was determined by three-color cytometric analysis. After in vitro cultivation of PBMC in the presence of PHA for 24 h, the mean percentages of marker-reactive cells of five PL+ cows were as follows; 43% +/- 4.5 of the PBMC expressed BLV-gp51 antigen; 90% +/- 1.6 of these cells expressed both IgM and CD5 at the same time, whereas but 7.5% +/- 1.9 expressed only IgM and 2.9% +/- 0.4 expressed only CD5. The PBMC, IgM positive cells accounted for 77.8% +/- 6.8, while both CD5 and BLV-gp51 were detected simultaneously on 52.0% +/- 2.4 of the IgM+ cells, while the CD5 marker and BLV-gp51 antigen were detected independently on 35.0% +/- 1.9 and in 9.0% +/- 3.1, respectively of the IgM+ cells. Of the CD5+ cells (equivalent to 75.5% +/- 9.0 of the PBMC), 54.7% +/- 4.7 expressed simultaneously IgM and BLV-gp51, while BLV-gp51 and IgM were expressed separately by 3.0% +/- 0.5 and 37.8% +/- 3.3, respectively. An association between the B-cell phenotype and BLV tropism might exist. It is also possible that cells bearing both IgM and CD5 markers are the main target cells for BLV infection.     

Effect of polypyrrole film on the stability and electrochemical activity of fluoride based graphite intercalation compounds in HF media

Fluoride intercalation/deintercalation cycles on commercially available high purity graphite electrodes leads to powder formation and electrode damage. Formation of polypyrrole films of optimum thickness by potential cycling on the graphite surface before fluoride intercalation leads to good mechanical stability to the electrode during intercalation/deintercalation cycles. The intercalation potential shifts by 200 mV in the positive direction. The intercalation and deintercalation charges (Q _a, Q _c) also decrease slightly. However the charge recovery ratio (Q _c/Q _a) improves significantly. Since the polypyrrole layer is compact on the graphite surface, the present study indicates that the film offers mechanical stability to the graphite film without affecting the electronic conductivity of the surface. F^– ion transport through the film also occurs with a small overvoltage.     

Chemical and Physical Properties of Copper-Based Catalysts for CO Shift Reaction and Methanol Synthesis

The modern low-pressure methanol synthesis catalysts are based on copper-containing systems such as Cu/ZnO/Al₂O₃ and Cu/ZnO/Cr₂O₃ with various compositions. These catalysts are also highly active for the low-temperature CO shift reaction. For both reactions the nature of the active sites is still an open question.     

Reversal of toxigenic effects of aflatoxin B1 on cockerels by alcoholic extract of African nutmeg,Monodora myristica

The reversal of the toxigenic effects of crystalline aflatoxin B₁ (AFB₁; from Aspergilus flavus) on cockerels using different concentrations of the ethanolic extract from the seeds of African nutmeg, Monodora myristica, was studied in 130 two‐week‐old cockerels, randomly divided into 13 groups (A–M) of ten birds each. Group A (controls) received 100 µl of phosphate‐buffered saline, while those in the test groups B, C and D received 690 ng, 1380 ng or 2010 ng of AFB₁, respectively; groups E to M received the three doses of AFB₁ with either 0.1, 0.2 or 0.3 ml of the extract of M myristica, respectively, 5 min after administration of AFB₁. Jugular blood, collected on days 14 and 21 after administration, was analysed for haematology parameters, serum proteins, alanine aminotransaminase (ALT), aspartate aminotransaminase (AST) and γ‐glutamyl transferase (GGT) levels. The birds were observed daily for clinical signs and mortality for 21 days. Post‐mortem examination was carried out on the livers of dead birds and those sacrificed by exsanguination after the 21 days post‐administration. One hundred per cent mortality was recorded in cockerels that received high doses of only AFB₁ within 72 h (2010 ng per bird), and between 17 and 19 days (1380 ng). The cockerels developed leucocytosis and microcytic hypochromic anaemia. Dosing with 0.2 or 0.3 ml of the extract of M myristica reversed these changes over time, while the lowest dose (0.1 ml) did not. While serum bilirubin levels rose significantly in test cockerels, no significant changes (P > 0.05) were observed in the levels of serum proteins of control and test cockerels, whether or not they received the extract of M myristica. Aflatoxicosis caused significant decreases and increases (P < 0.05) in serum AST and GGT levels, respectively, while the administration of alcoholic extract of M myristica reversed the GGT but not AST levels to normal. Livers from control cockerels and those given 2010 ng of AFB₁ showed no appreciable gross or histological lesions. The other groups showed mild to moderate hepatomegaly, paleness and friability, diffuse vacuolar degeneration and necrosis, Kupffer cell proliferation, presence of megalocytes and multinucleated hepatocytes. Cockerels that received 0.2 or 0.3 ml of extract of M myristica, irrespective of the dose of AFB₁ showed the mildest hepatic lesions. The results of this study show that AFB₁ is highly toxigenic to cockerels and that this could be successfully reversed by the concurrent administration of alcoholic extract of M myristica. It is therefore recommended that reduction of fungal growth on foods and subsequent toxicosis by aeration, cooling, modified atmospheres or by fungistats, is complemented with the use of extracts of spices from M myristica seed, a tree widely distributed along the west coast and central Africa. Copyright © 2004 Society of Chemical Industry     

Post-occupancy evaluation in architecture: experiences and perspectives from UK practice

The importance of post-occupancy evaluation (POE) is widely acknowledged in the academic literature, industry press and, increasingly, by professional institutes. Learning from previous projects systematically is central to improving building performance, resulting in a built environment that better fits the needs of clients, end users, wider society and the environment. The key role of architects in pushing forward this agenda has been recognized, however evidence suggests that take up of POE is low across the profession. Whilst research has investigated barriers to POE across the construction industry, very little has considered the unique perspective of architects. In-depth interviews with UK-based architects are presented to explore their experiences in relation to POE and their perspectives on its potential to be a standard part of architectural practice. The findings indicate that a considerable amount of practical work is being undertaken, but uncertainty over what constitutes POE means it is often excluded from the POE label – with significant implications for the development of a rigorous evidence base. An appetite is identified for more holistic evaluation measures that move beyond the current preoccupation with energy efficiency to consider other aspects of building performance, and thereby sustainability, in a wider value framework.     

Light‐Activated Triazabutadienes for the Modification of a Viral Surface

Chemical crosslinking is a versatile tool for the examination of biochemical interactions, in particular host–pathogen interactions. We report the critical first step toward the goal of probing these interactions by the synthesis and use of a new heterobifunctional crosslinker containing a triazabutadiene scaffold. The triazabutadiene is stable to protein conjugation and liberates a reactive aryl diazonium species upon irradiation with 350 nm light. We highlight the use of this technology by modifying the surface of several proteins, including the dengue virus envelope protein.