Effects of Insemination Quantity on Honey Bee Queen Physiology

Mating has profound effects on the physiology and behavior of female insects, and in honey bee (Apis mellifera) queens, these changes are permanent. Queens mate with multiple males during a brief period in their early adult lives, and shortly thereafter they initiate egg-laying. Furthermore, the pheromone profiles of mated queens differ from those of virgins, and these pheromones regulate many different aspects of worker behavior and colony organization. While it is clear that mating causes dramatic changes in queens, it is unclear if mating number has more subtle effects on queen physiology or queen-worker interactions; indeed, the effect of multiple matings on female insect physiology has not been broadly addressed. Because it is not possible to control the natural mating behavior of queens, we used instrumental insemination and compared queens inseminated with semen from either a single drone (single-drone inseminated, or SDI) or 10 drones (multi-drone inseminated, or MDI). We used observation hives to monitor attraction of workers to SDI or MDI queens in colonies, and cage studies to monitor the attraction of workers to virgin, SDI, and MDI queen mandibular gland extracts (the main source of queen pheromone). The chemical profiles of the mandibular glands of virgin, SDI, and MDI queens were characterized using GC-MS. Finally, we measured brain expression levels in SDI and MDI queens of a gene associated with phototaxis in worker honey bees (Amfor). Here, we demonstrate for the first time that insemination quantity significantly affects mandibular gland chemical profiles, queen-worker interactions, and brain gene expression. Further research will be necessary to elucidate the mechanistic bases for these effects: insemination volume, sperm and seminal protein quantity, and genetic diversity of the sperm may all be important factors contributing to this profound change in honey bee queen physiology, queen behavior, and social interactions in the colony

Queen mandibular pheromone: questions that remain to be resolved

The discovery of ‘queen substance’, and the subsequent identification and synthesis of keycomponents of queen mandibular pheromone, has been of significant importance to beekeepers and to thebeekeeping industry. Fifty years on, there is greater appreciation of the importance and complexity of queenpheromones, but many mysteries remain about the mechanisms through which pheromones operate. Thediscovery of sex pheromone communication in moths occurred within the same time period, but in this case,intense pressure to find better means of pest management resulted in a remarkable focusing of research activityon understanding pheromone detection mechanisms and the central processing of pheromone signals in themoth. We can benefit from this work and here, studies on moths are used to highlight some of the gaps in ourknowledge of pheromone communication in bees. A better understanding of pheromone communication inhoney bees promises improved strategies for the successful management of these extraordinary animals

At the Crossroads of Sustainability: The Natural Recompositioning of Architecture

It is widely acknowledged that the mantra of sustainability has triggered a fundamental reversal in the core of design practice: If the original purpose of architecture was to protect humans from the destructive actions of nature,today it should protect nature from the damaging actions of humans. But sustainable design is far from being a coherent body of fully totalized ideas:it has a broad spectrum of disputing interpretations that oscillate between the deterministic models of energy control and technological efficiencies, and the moralistic and romantic approaches that attempt to see in nature and natural processes a fundamental way to de-escalate the global urban footprint and its associated patterns of consumption. However, mainstream green design has been evolving by progressively absorbing the narrative of deep ecology. Nature has been being integrated into architecture literally, by inserting vegetation onto buildings; digitally, by bringing environmental data into the design process (climate records, wind streams, sun rotation and air flows are computed, modelled and effectually shape architectures), and transcendentally, by claiming that sustainable architecture nurtures “the existing and evolving connections between spiritual and material consciousness.” The acknowledgement of the inexorable affiliation between architecture and the environment is, of course, not exactly new. What is distinctive today is the reification of the role of nature in architecture as an ideological stance, now totally intertwined with state-of-art data processing and the market-driven tools brought by Natural Capitalism. This paper will examine emblematic “green” buildings produced by leading architects such as Pelli Clarke Pelli, William McDonough, Stefano Boeri, Norman Foster and BIG in the light of Tim Morton’s, Slavoj Zizek and Bruno Latour’s critique of nature. It will illustrate how, despite being able to successfully forge new creative freedoms by exploring hybridizations between the domains of design and science, sustainability’s self-righteous “naturalistic” narrative is enabling a vision of the architect as an “expert manager” focused on producing projects of ecologic “beautification” while assumed to be “saving the world,” effectively depoliticizing the architectural practice. Nevertheless, these examples attest that there is a vast and fertile field of ideas to be explored and in this regard it is important to underline that we are still in the embryonic outset of the engagement of architecture with sustainability

Report from the Annual Conference of the British Society of Echocardiography, November 2017, Edinburgh International Conference Centre, Edinburgh

No abstract available

Aspects of turbulent-shear-layer dynamics and mixing

Experiments have been conducted in the GALCIT Supersonic Shear Layer Facility to investigate some aspects of high-Reynolds-number, turbulent, shearlayer flows in both incompressible- and compressible-flow regimes. Experiments designed to address several issues were performed; effects of inflow boundary conditions, freestream conditions (supersonic/subsonic flow), and compressibility, on both large-scale dynamics and small-scale mixing, are described. Chemically-reacting and non-reacting flows were investigated, the former relying on the (H2 + NO/F2) chemical system, in the fast-kinetic regime, to infer the structure and amount of molecular-scale mixing through use of "flip" experiments. A variety of experimental techniques, including a color-schlieren visualization system developed as part of this work, were used to study the flows. Both inflow conditions and compressibility are found to have significant effects on the flow. In particular, inflow conditions are "remembered" for long distances downstream, a sensitivity similar to that observed in low-dimensionality, non-linear (chaotic) systems. The global flowfields (freestreams coupled by the shear layer) of transonic flows exhibit a sensitivity to imposed boundary conditions, i. e., local area ratios. A previously-proposed mode-selection rule for turbulent-structure convection speeds, based on the presence of a lab-frame subsonic freestream, was experimentally demonstrated to be incorrect. Compressibility, when decoupled from all other parameters, e.g., Reynolds number, velocity and density ratios, etc., reduces laxge-scale entrainment and turbulent growth, but slightly enhances smallscale mixing, with an associated change in the structure of the molecularly-mixed fluid. This reduction in shear-layer growth rate is examined and a new parameter that interprets compressibility as an energy-exchange mechanism is proposed. The parameter reconciles and collapses experimentally-observed growth rates

Cloning, expression and purification of cindoxin, an unusual FMN-containing cytochrome P450 redox partner

Cytochromes P450 (P450s) belong to a superfamily of haemoproteins that catalyse a remarkable variety of oxidative transformations. P450 catalysis generally requires that cognate redox proteins transfer electrons, derived ultimately from NAD(P)H, to the P450 for oxygen activation. P450 (CYP176A1) is a bacterial P450 that is postulated to allow Citrobacter braakii to live on cineole as its sole carbon source by initiating cineole biodegradation. Here we report the cloning, expression, purification and characterisation of one of its postulated redox partners, cindoxin (Cdx), which has strong similarity to the FMN domain of cytochrome P450 reductase. Cindoxin reductase (CdR), which displays strong similarity to NADPH-dependent ferredoxin reductases, was unable to be expressed in a functional form. Mass spectrometric and HPLC analyses confirmed that the flavin cofactor of cindoxin was FMN. Redox potentiometric titrations were performed with cindoxin within the range

Cineole biodegradation: Molecular cloning, expression and characterisation of (1R)-6beta - hydroxycineole dehydrogenase from Citrobacter braakii

The first steps in the biodegradation of 1,8-cineole involve the introduction of an alcohol and its subsequent oxidation to a ketone. In Citrobacter braakii, cytochrome P450 has previously been demonstrated to perform the first oxidation to produce (1R)-6β-hydroxycineole. In this study, we have cloned cinD from C. braakii and expressed the gene product, which displays significant homology to a number of short-chain alcohol dehydrogenases. It was demonstrated that the gene product of cinD exhibits (1R)-6β-hydroxycineole dehydrogenase activity, the second step in the degradation of 1,8-cineole. All four isomers of 6-hydroxycineole were examined but only (1R)-6β-hydroxycineole was converted to (1R)-6-ketocineole. The (1R)-6β-hydroxycineole dehydrogenase exhibited a strict requirement for NAD(H), with no reaction observed in the presence of NADP(H). The enzyme also catalyses the reverse reaction, reducing (1R)-6-ketocineole to (1R)-6β-hydroxycineole. During this study the N-terminal His-tag used to assist protein purification was found to interfere with NAD(H) binding and lower enzyme activity. This could be recovered by the addition of Ni ions or proteolytic removal of the His-tag

An in vivo cytochrome P450(cin) (CYP176A1) catalytic system for metabolite production

Cytochrome P450 (CYP176A1) is a bacterial P450 isolated from Citrobacter braakii that catalyses the hydroxylation of 1,8-cineole to (1R)-6β-hydroxycineole. P450 uses two redox partners in vitro for catalysis: cindoxin, its physiological FMN-containing redox partner, and Escherichia coli flavodoxin reductase. Here we report the construction of a tricistronic plasmid that expresses P450 , cindoxin and E. coli flavodoxin reductase and a bicistronic plasmid that encodes only P450 and cindoxin. E. coli transformed with the bicistronic vector effectively catalysed the oxidation of 1,8-cineole, with the endogenous E. coli flavodoxin reductase presumably acting as the terminal electron transfer protein. This in vivo system was capable of producing enantiomerically pure (1R)-6β-hydroxycineole in yields of ∼1 g/L culture, thus providing a simple, one-step synthesis of this compound. In addition, the metabolism of (1R)- and (1S)-camphor, structural homologues of 1,8-cineole was also evaluated in order to investigate the ability of this in vivo system to produce compounds for mechanistic studies. Significant quantities of five of the six possible secondary alcohols arising from methylene oxidation of both (1R)- and (1S)-camphor were isolated and structurally characterised. The similarity of the (1R)- and (1S)-camphor product profiles highlight the importance of the inherent reactivity of the substrate in determining the regiochemistry of oxidation in the absence of any specific enzyme-substrate binding interactions