Beetles with ‘trochantelli’: phylogeny of Cephenniini (Coleoptera: Staphylinidae: Scydmaeninae) focussing on Neotropical genera

Neotropical genera of Cephenniini characterized by an additional leg ‘segment’ (‘trochantellus’) are revised, and the following new taxa are described: Shyri gen.n. , Shyri pichincha sp.n. (type species of Shyri) (Ecuador), Shyri perversus sp.n. (Ecuador), Shyri quitu sp.n. (Ecuador), Shyri microphthalmus sp.n. (Ecuador), Monstrophennium gen.n. (type species: Cephennium spinicolle Schaufuss), Furcodes gen.n. , Furcodes apicalis sp.n. (type species of Furcodes) (Mexico), Furcodes tutule sp.n. (Honduras), Paracephennium pumilio sp.n. (Costa Rica), Pseudocephennium iwokramanum sp.n. (Guyana), Pseudocephennium trilineatum sp.n. (Guyana), Pseudocephennium araguanum sp.n. (Venezuela), Pseudocephennium maximum sp.n. (Venezuela), Pseudocephennium peruvianum sp.n. (Peru), Pseudocephennium cochabambanum sp.n. (Bolivia), Pseudocephennium saramaccanum sp.n. (Suriname) and Pseudocephennium brokopondonum sp.n. (Suriname). Pseudocephennium spinicolle (Schaufuss) is transferred to Monstrophennium. Cladistic analysis of characters from adult morphology of all genera of Cephenniini and a large outgroup sample from Cyrtoscydmini, Eutheiini, Scydmaenini, Clidicini and Mastigini strongly supported the monophyly of Cephenniini. However, only the Cephennomicrus group comprising nine genera was strongly supported as a monophyletic clade, while only weak support was found for the previously suggested Cephennodes group and Cephennium group. Two alternative hypotheses concerning the phylogeny of Cephenniini are put forward and discussed: (i) the Cephennium group is sister to all remaining Cephenniini; or (ii) the Cephennomicrus group is sister to all remaining Cephenniini. The Neotropical genera with ‘trochantellus’ form a well‐supported clade derived from the ancestral lineage of the Cephennodes group.     

Strategies for promoting division of cultured plant protoplasts: synergistic beneficial effects of haemoglobin (Erythrogen) and Pluronic F-68

Novel approaches, involving supplementation of aqueous culture medium with haemoglobin solution (Erythrogen), in the presence or absence of the copolymer surfactant, Pluronic F-68, have been evaluated to facilitate cellular oxygen availability to promote mitotic division. Cell-suspension-derived protoplasts of albino Petunia hybrida cv. Comanche were cultured for up to 45 days in KM8P medium containing 1:50–1:500 (vol:vol) Erythrogen. The mean initial protoplast plating efficiency after 9 days with 1:50 Erythrogen (18.5%) was significantly greater (P<0.05) than in untreated controls (11.3%). Supplementation of culture medium with 1:50 Erythrogen, together with 0.01% (wt/vol) Pluronic F-68, increased the mean plating efficiency after 9 days (24.4%) by 92% (P<0.05) over the control (12.7%). These treatments also produced increases in biomass of protoplast-derived cells up to 2.5-fold greater than control (P<0.01) over 80 days. Gassing the medium, containing 1:50 Erythrogen, with carbon monoxide abolished the increase in plating efficiency. There was no additional benefit of gassing Erythrogen-supplemented medium with 100% oxygen. The synergistic, beneficial effect of Erythrogen and Pluronic F-68 on protoplast division has implications for plant biotechnology utilising protoplasts. Received: 24 May 1996 / Revision received: 12 July 1996 / Accepted: 15 August 1996     

Climate change and heat-related mortality in six cities Part 2: climate model evaluation and projected impacts from changes in the mean and variability of temperature with climate change

Previous assessments of the impacts of climate change on heat-related mortality use the “delta method” to create temperature projection time series that are applied to temperature–mortality models to estimate future mortality impacts. The delta method means that climate model bias in the modelled present does not influence the temperature projection time series and impacts. However, the delta method assumes that climate change will result only in a change in the mean temperature but there is evidence that there will also be changes in the variability of temperature with climate change. The aim of this paper is to demonstrate the importance of considering changes in temperature variability with climate change in impacts assessments of future heat-related mortality. We investigate future heat-related mortality impacts in six cities (Boston, Budapest, Dallas, Lisbon, London and Sydney) by applying temperature projections from the UK Meteorological Office HadCM3 climate model to the temperature–mortality models constructed and validated in Part 1. We investigate the impacts for four cases based on various combinations of mean and variability changes in temperature with climate change. The results demonstrate that higher mortality is attributed to increases in the mean and variability of temperature with climate change rather than with the change in mean temperature alone. This has implications for interpreting existing impacts estimates that have used the delta method. We present a novel method for the creation of temperature projection time series that includes changes in the mean and variability of temperature with climate change and is not influenced by climate model bias in the modelled present. The method should be useful for future impacts assessments. Few studies consider the implications that the limitations of the climate model may have on the heat-related mortality impacts. Here, we demonstrate the importance of considering this by conducting an evaluation of the daily and extreme temperatures from HadCM3, which demonstrates that the estimates of future heat-related mortality for Dallas and Lisbon may be overestimated due to positive climate model bias. Likewise, estimates for Boston and London may be underestimated due to negative climate model bias. Finally, we briefly consider uncertainties in the impacts associated with greenhouse gas emissions and acclimatisation. The uncertainties in the mortality impacts due to different emissions scenarios of greenhouse gases in the future varied considerably by location. Allowing for acclimatisation to an extra 2°C in mean temperatures reduced future heat-related mortality by approximately half that of no acclimatisation in each city.     

A single half-turnover of the glucose carrier of the human erythrocyte

Single half-turnovers of the glucose carrier of the human erythrocyte have been measured by recruiting carriers to the outward-facing conformation by (a) pre-exposing cells to extracellular maltose, or (b) pre-warming cells to 38 degrees C, before addition of D-[14C]glucose at 0 degrees C. Based on these experiments estimates of the number of glucose carriers per red cell range from 124,000 to 190,000.     

Kinetics and mechanism of the reaction of cyanide with molybdenum nitrogenase from Azotobacter vinelandii

The steady-state kinetic behavior of the six-electron reduction of N2 by nitrogenase is known to differ markedly from the six-electron reduction of cyanide in two ways. First, on extrapolation to infinite concentration of cyanide, the H2 evolution reaction is almost completely suppressed whereas at extrapolated infinite concentration of N2, H2 evolution continues. Second, as the ratio of the Fe protein to the MoFe protein increases, the reduction of N2 is favored over H2 evolution, whereas the reduction of cyanide becomes less favored relative to H2 evolution. We have extended these steady-state experiments with Azotobacter vinelandii nitrogenase to include a third observation, that the six-electron reduction of N2 is favored over H2 evolution at high total protein concentrations whereas cyanide reduction is less favored over H2 evolution at high total protein concentrations. All three steady-state observations can be explained by a model whereby cyanide is proposed to bind to a redox state of the MoFe protein more oxidized than that reactive toward H2 evolution and N2 reduction. To test this model, we have examined the pre-steady-state kinetic behavior of both cyanide reduction by A. vinelandii nitrogenase and cyanide inhibition of total electron flow through nitrogenase. The data show that in the presence or absence of cyanide there is a short lag of 100 ms before H2 is detected, followed by a linear phase of H2 evolution lasting for about 3 s, during which time no effects of cyanide are observable. After 3 s electron flow is finally inhibited by cyanide, and the cyanide reduction product CH4 is finally formed.(ABSTRACT TRUNCATED AT 250 WORDS)