Three-dimensional localization: from image-guided surgery to information-guided therapy.

Image-guided surgery has become the standard of care for intracranial procedures. However, significant development is required before the benefits of this technology are brought to the majority of patients undergoing surgery. This article categorizes the areas wherein progress is needed, and indicates recent advances that may form the basis for the broad acceptance of this exciting technology. Emphasis is placed on a technique whereby preoperative imaging can be updated using low-resolution intraoperative imaging to reflect changes in anatomy caused by surgery, and on transforming image-guided surgery to information-guided therapy, in which diverse sources can be brought to bear at the time of greatest possible benefit, when the patient's anatomy is exposed for therapeutic intervention.     

The genetic architecture of fitness in a seed beetle: assessing the potential for indirect genetic benefits of female choice

Background  

Quantifying the amount of standing genetic variation in fitness represents an empirical challenge. Unfortunately, the shortage of detailed studies of the genetic architecture of fitness has hampered progress in several domains of evolutionary biology. One such area is the study of sexual selection. In particular, the evolution of adaptive female choice by indirect genetic benefits relies on the presence of genetic variation for fitness. Female choice by genetic benefits fall broadly into good genes (additive) models and compatibility (non-additive) models where the strength of selection is dictated by the genetic architecture of fitness. To characterize the genetic architecture of fitness, we employed a quantitative genetic design (the diallel cross) in a population of the seed beetle Callosobruchus maculatus, which is known to exhibit post-copulatory female choice. From reciprocal crosses of inbred lines, we assayed egg production, egg-to-adult survival, and lifetime offspring production of the outbred F1 daughters (F1 productivity).     

Repression and Recuperation of Brood Production in Bombus terrestris Bumble Bees Exposed to a Pulse of the Neonicotinoid Pesticide Imidacloprid

Currently, there is concern about declining bee populations and some blame the residues of neonicotinoid pesticides in the nectar and pollen of treated crops. Bumble bees are important wild pollinators that are widely exposed to dietary neonicotinoids by foraging in agricultural environments. In the laboratory, we tested the effect of a pulsed exposure (14 days ‘on dose’ followed by 14 days ‘off dose’) to a common neonicotinoid, imidacloprid, on the amount of brood (number of eggs and larvae) produced by Bombus terrestris L. bumble bees in small, standardised experimental colonies (a queen and four adult workers). During the initial ‘on dose’ period we observed a dose-dependent repression of brood production in colonies, with productivity decreasing as dosage increased up to 98 µg kg⁻¹ dietary imidacloprid. During the following ‘off dose’ period, colonies showed a dose-dependent recuperation such that total brood production during the 28-day pulsed exposure was not correlated with imidacloprid up to 98 µg kg⁻¹. Our findings raise further concern about the threat to wild bumble bees from neonicotinoids, but they also indicate some resilience to a pulsed exposure, such as that arising from the transient bloom of a treated mass-flowering crop.     

Multiple, non-allelic, intein-coding sequences in eukaryotic RNA polymerase genes

Background  

Inteins are self-splicing protein elements. They are translated as inserts within host proteins that excise themselves and ligate the flanking portions of the host protein (exteins) with a peptide bond. They are encoded as in-frame insertions within the genes for the host proteins. Inteins are found in all three domains of life and in viruses, but have a very sporadic distribution. Only a small number of intein coding sequences have been identified in eukaryotic nuclear genes, and all of these are from ascomycete or basidiomycete fungi.     

Thermothrix thioparus gen. et sp. nov. a facultatively anaerobic facultative chemolithotroph living at neutral pH and high temperature.

Thermothrix thioparus gen. et ep. nov. occurs naturally in a New Mexico hot spring at a temperature of 74 degrees C, a pH of 7.0, and a HS- concentration of 1 mg/litre. The organism is gram-negative, non-motile, 0.5-1.0 X 3-20 mum, and forms cell chains up to 1 cm in length. The resulting filaments do not possess a sheath. Sulfur is deposited extracellularly. The organism was isolated using an autotrophic medium with HS- as the energy source and NO3- as the terminal electron acceptor. Anaerobically either NO2- or NO3- is required, NO2- is formed from NO3-, and no observable gas is evolved. Oxygen can also be used as the terminal electron acceptor, but growth is poor because of the decreased solubility of O2 at temperatures required for growth. Alternate energy sources used aerobically and anaerobically include hexose, HS-, SO3-, and S2O3=. The temperature optimum is 70-73 degrees C and growth occurs from 62 to 77 degrees C. The organism's thermal and physiological characteristics are compared to those of Bacillus stearothermophilus, Methanobacterium thermoautotrophicum, Sulfolobus acidocalderius, Thermus aquaticus, Thermus flavus, as well as Thiobacillus denitrificans, the latter being the only other facultatively anaerobic chemolithotroph which has been isolated and described.