Odors: from chemical structures to gaseous plumes

We are immersed within an odorous sea of chemical currents that we parse into individual odors with complex structures. Odors have been posited as determined by the structural relation between the molecules that compose the chemical compounds and their interactions with the receptor site. But, naturally occurring smells are parsed from gaseous odor plumes. To give a comprehensive account of the nature of odors the chemosciences must account for these large distributed entities as well. We offer a focused review of what is known about the perception of odor plumes for olfactory navigation and tracking, which we then connect to what is known about the role odorants play as properties of the plume in determining odor identity with respect to odor quality. We end by motivating our central claim that more research needs to be conducted on the role that odorants play within the odor plume in determining odor identity

Studies of glutathione metabolism in sheep erythrocytes

The tripeptide, reduced glutathione (GSH), is present in high concentration in mammalian erythrocytes, where its major role is the protection of the cell against oxidative damage. Sheep exhibit two distinct types of erythrocyte GSH deficiency. In Finnish Landrace sheep (Finns) low GSH is inherited as an autosomal recessive trait, and is associated with a markedly diminished erythrocyte life-span, and the presence of unusually high concentrations of some erythrocyte amino acids, notably ornithine and lysine. In contrast, in Tasmanian Merino sheep (Merinos) the low GSH characteristic is inherited in an autosomal dominant manner and both the erythrocyte life -span and amino acid concentrations are normal. This Thesis describes an investigation of the biochemical mechanisms responsible for the Finn and Merino erythrocyte GSH deficiencies. The Finn and Merino sheep investigated were maintained by the ARC Animal Breeding Research Organisation, Edinburgh. Both breeds contained substantial numbers of GSH-deficient animals. In agreement with other studies, GSH-deficient Finn erythrocytes were found to contain very high concentrations of ornithine and lysine, a phenomenon not encountered in Merinos. Sheep were allotted their GSH type on the basis of their erythrocyte total non -protein reduced thiol concentration as determined by the non-specific thiol reagent 5,5'-dithiobis-(-2-nitrobenzoate) (DTNB). The validity of equating total DTNB reactive thiol with GSH was established by estimating GSH using novel automated versions of methods employing DTNB and alloxan as chromogens. GSH-deficient erythrocytes of both breeds were also found to have a diminished GSSG concentration so that they had a diminished total glutathione content (GSH + 2GSSG). The alloxan GSH and GSSG estimates were used to calculate the redox potential of the GSH:GSSG couple in the various cell types. In both breeds the difference in redox potential between normal and GSH-deficient cells was small. It is suggested that the diminished life-span of GSH-deficient Finn cells may not be a direct consequence of their GSH status. Merino GSH-deficient erythrocytes had a markedly diminished maximum activity of δ-glutamyl cysteine synthetase (GC-S) and computer simulation studies provided evidence that this enzyme is the rate-limiting one for GSH biosynthesis in sheep erythrocytes. The low GC-S activity of these cells may therefore be responsible for the GSH deficiency. Sheep erythrocyte GC-S was markedly inhibited by physiological GSH concentrations. The diminished GSH feedback inhibition in GSH-deficient Merino cells was insufficient to compensate for their low GC-S activity. Reticulocytes from Merinos of both GSH types had similar very high GSH concentrations and GC-S activities. The differentiation into normal and GSH-deficient cells therefore occurs at some stage during reticulocyte maturation. In contrast to the situation in Merinos, the GC-S activity of GSH-deficient Finn erythrocytes was normal. The activity of GSH synthetase (the second enzyme of GSH biosynthesis) and the ATP concentration of these cells was also normal, and they did not appear to contain an inhibitor of GSH biosynthesis (other than GSH). Their ability to maintain glutathione in the reduced state was unimpaired. However GSH-deficient Finn cells were much less permeable to cysteine and lysine than normal Finn cells. In contrast, the amino acid permeability of normal and GSH-deficient Merino erythrocytes was the same, and not significantly different from that found in normal Finn cells. It is concluded that the diminished amino acid permeability of GSH- deficient Finn cells represents a membrane transport defect. It further seems likely that diminished availability of cysteine is responsible for the low concentration of GSH in these cells, and that the accumulation of lysine and ornithine is a further reflection of reduced amino acid transport. During these investigations a novel enzymic activity was discovered by chance in a commercial preparation of glucose oxidase from Aspergillus niger. The reaction catalysed was: 2GSH + O₂→ GSSG + H₂O₂ The enzyme was specific for GSH, and could be separated from glucose oxidase by ion-exchange chromatography

Less government intervention in biodiversity management: risks and opportunities

n a changing global environment, with increasing pressure on ecosystem goods and services, biodiversity conservation is likely to become increasingly important. However, with the current global financial crisis, governments are increasingly trying to stabilise economies through spending cuts aiming to reduce national deficits. Within such an economic climate, the devolution of governance through public participation is an intrinsically appealing concept. We outline a number of challenges that explain why increased participation in biodiversity management has been and may continue to be problematic. Using as a case study the local stakeholder-driven Moray Firth Seal Management Plan in Scotland, we identify four key conditions that were crucial to the successful participatory management of a biodiversity conflict: a local champion, the emergence of a crisis point, the involvement of decision-makers, and long-term financial and institutional support. Three of the four conditions point to the role of direct government involvement, highlighting the risk of devolving responsibility for biodiversity conflict management to local communities. We argue that without an informed debate, the move towards a more participatory approach could pose a danger to hard-won policy gains in relation to public participation, biodiversity conservation and conflict management

Cost effective combined axial fan and throttling valve control of ventilation rate

This paper is concerned with Proportional-Integral-Plus (PIP) control of ventilation rate in mechanically ventilated agricultural buildings. In particular, it develops a unique fan and throttling valve control system for a 22m3 test chamber, representing a section of a livestock building or glasshouse, at the Katholieke Universiteit Leuven. Here, the throttling valve is employed to restrict airflow at the outlet, so generating a higher static pressure difference over the control fan. In contrast with previous approaches, however, the throttling valve is directly employed as a second control actuator, utilising airflow from either the axial fan or natural ventilation. The new combined fan/valve configuration is compared with a commercially available PID-based controller and a previously developed scheduled PIP design, yielding a reduction in power consumption in both cases of up to 45%

NOTE First Records of Alcathoe carolinensis Engelhardt and Synanthedon alleri (Engelhardt) in South Carolina, U.S.A.1

Clearwing moths (Lepidoptera: Sesiidae) are day-flying hornet and wasp mimics that can be found visiting flowers for nectar. Larvae bore in the roots, branches and trunks of woody and some herbaceous plants. Some of these larvae are pests in orchards, nurseries and commercial forestry operations. For example, Synanthe- don exitiosa (Say) and Synanthedon pictipes (Grote & Robinson) are major pests of peach [Prunus persica (L.) Batsch; Rosaceae] (Johnson et al. 2005), and Synanthe- don scitula (Harris) is a major pest of apple (Malus domestica Borkh.; Rosaceae) (Bergh & Leskey 2003). These species, and Podosesia syringae (Harris), Podosesia aureocincta Purrington & Nielsen and Paranthrene simulans (Grote) are pests of ornamental trees (Brown and Mizell 1993, Braxton & Raupp 1995, Held 2019). About 135 sesiid species in 20 genera occur in North America (Pühringer & Kallies 2004, Pohl et al. 2016). Forty-four species are likely to occur in South Carolina based on collection records from South Carolina and neighboring states documented in Eichlin & Duckworth (1988). This species richness has not been validated with a comprehensive survey of sesiid diversity in the state. As a first step to better understand sesiid species diversity in South Carolina, a survey was conducted in three counties (Darlington, Georgetown and Pickens) from March 2011 to December 2013. A mixed pine-hardwood forest, an ornamental plant nursery and a botanical garden were surveyed in each of Darlington and Georgetown Counties to diversify the habitats and outcome of this exploratory survey. In Pickens County, a single ornamental plant nursery was surveyed. Surveyed locations in Georgetown County lay within the Sea Island and Coastal Marsh Ecoregion, those in Darlington County within the Atlantic Southern Loam Plain Ecoregion, and that in Pickens County within the Southern Outer Piedmont Ecoregion (Griffith et al. 2002). Locations within a county were separated by at least 20 km

First Records of Alcathoe carolinensis Engelhardt and Synanthedon alleri (Engelhardt) in South Carolina, U.S.A.

Clearwing moths (Lepidoptera: Sesiidae) are day-flying hornet and wasp mimics that can be found visiting flowers for nectar. Larvae bore in the roots, branches and trunks of woody and some herbaceous plants. Some of these larvae are pests in orchards, nurseries and commercial forestry operations. For example, Synanthedon exitiosa (Say) and Synanthedon pictipes (Grote & Robinson) are major pests of peach [Prunus persica (L.) Batsch; Rosaceae] (Johnson et al. 2005), and Synanthedon scitula (Harris) is a major pest of apple (Malus domestica Borkh.; Rosaceae) (Bergh & Leskey 2003). These species, and Podosesia syringae (Harris), Podosesia aureocincta Purrington & Nielsen and Paranthrene simulans (Grote) are pests of ornamental trees (Brown and Mizell 1993, Braxton & Raupp 1995, Held 2019). About 135 sesiid species in 20 genera occur in North America (Pühringer & Kallies 2004, Pohl et al. 2016). Forty-four species are likely to occur in South Carolina based on collection records from South Carolina and neighboring states documented in Eichlin & Duckworth (1988). This species richness has not been validated with a comprehensive survey of sesiid diversity in the state. As a first step to better understand sesiid species diversity in South Carolina, a survey was conducted in three counties (Darlington, Georgetown and Pickens) from March 2011 to December 2013. A mixed pine-hardwood forest, an ornamental plant nursery and a botanical garden were surveyed in each of Darlington and Georgetown Counties to diversify the habitats and outcome of this exploratory survey. In Pickens County, a single ornamental plant nursery was surveyed. Surveyed locations in Georgetown County lay within the Sea Island and Coastal Marsh Ecoregion, those in Darlington County within the Atlantic Southern Loam Plain Ecoregion, and that in Pickens County within the Southern Outer Piedmont Ecoregion (Griffith et al. 2002). Locations within a county were separated by at least 20 km