Studies on the relationship between genes and enzymes

The experimental work and theoretical discussion presented here suggests the following main conclusions.1. Argininosuccinase may be detected in extracts of a standard wild -type (SLA) and measurements may be made of some of the kinetics of its catalysis. I:t is considered likely, from these kinetic data and from the information on the behaviour of the enzyme on hydroxylapatite gel and on electrophoresis, that the enzyme is a single protein species.2. A report is given of an examination of some of the arg-10 mutants and of a heterokaryon between two of them.3.. The production and genetics of revertants of some of these arg-10 mutants, is described and it is suggested that at least two of the revertants (362r-1 and 362r-2) are the result of mutation(s) at or close to the arg-10 locus.4. The argininosuccinase formed by 362r-1 is described and it is proposed that the differences between this enzyme and that of the original wild-type (SLA) may be explained as the result of an alteration to the structure of the enzyme involving the active site.5. The argininosuccinase formed by 362r-2 is described and it is proposed that this enzyme differs both from that found in SLA and in 362r-1 and that this is also a reflection of an alteration in the structure of the active site of the enzyme.6. Some of the properties of argininosuccinase from K32 3-revertants are described and it is suggested that they may not differ in any way from the enzyme of SLA.7. A discussion is given of the growth of Neurospora crassa in culture and it is concluded that the growth -curves of the organism are complex and depend on the culture conditions.8. Measurements of argininosuccinase, argininosuccinic acid and arginine in cultures of SLA and 362r-1 are reported and the results obtained are explained in terms of a kinetic model of the arginine pathway in vivo. It is suggested that the concentration of arginine must always be independent of argininosuccinase concentration (at steady-state).9. In a discussion of the experiments and theory presented, the thesis is proposed that there are at least two major classes of catalyses, 'buffered" and "unbuffered", and that the genes affecting the enzymes concerned with these two types of catalyses will have distinct properties

Preparing for animal health emergencies: considerations for economic evaluation

Livestock production systems and the societies in which they are embedded face a set of risks presented by infectious diseases and natural and human-made disasters which compromise animal health. Within this set, threats are posed by natural, deliberate and accidental actions that can cause sudden changes in animal health status, requiring the allocation of additional resources to manage animal health. Determining the benefit of preparing for such emergencies is a challenge when the total set of risks includes the unknown. Any method for analysing the economic costs and benefits of animal health emergencies must not only accommodate this uncertainty, but make it a central feature of the analysis. Cost-benefit analysis is a key approach to economically evaluating animal health interventions. However, the value of this approach in dealing with uncertainty is often called into question. This paper makes the case that, by restricting the outcomes of an emergency event to specified states of nature, boundaries can be placed on the uncertainty space, allowing cost-benefit analysis to be performed. This method, which merges state-contingent analysis with cost-benefit analysis, is presented here. Further discussion on the economic characteristics of emergency events, and the nature of the threats posed to animal health systems, is also provided.D. Adamson, W. Gilbert, K. Hamilton, D. Donachie and J. Rushto

Cultivation and Complete Genome Sequencing of Gloeobacter kilaueensis sp. nov., from a Lava Cave in Kīlauea Caldera, Hawai'i

The ancestor of Gloeobacter violaceus PCC 7421T is believed to have diverged from that of all known cyanobacteria before the evolution of thylakoid membranes and plant plastids. The long and largely independent evolutionary history of G. violaceus presents an organism retaining ancestral features of early oxygenic photoautotrophs, and in whom cyanobacteria evolution can be investigated. No other Gloeobacter species has been described since the genus was established in 1974 (Rippka et al., Arch Microbiol 100:435). Gloeobacter affiliated ribosomal gene sequences have been reported in environmental DNA libraries, but only the type strain's genome has been sequenced. However, we report here the cultivation of a new Gloeobacter species, G. kilaueensis JS1T, from an epilithic biofilm in a lava cave in Kīlauea Caldera, Hawai'i. The strain's genome was sequenced from an enriched culture resembling a low-complexity metagenomic sample, using 9 kb paired-end 454 pyrosequences and 400 bp paired-end Illumina reads. The JS1T and G. violaceus PCC 7421T genomes have little gene synteny despite sharing 2842 orthologous genes; comparing the genomes shows they do not belong to the same species. Our results support establishing a new species to accommodate JS1T, for which we propose the name Gloeobacter kilaueensis sp. nov. Strain JS1T has been deposited in the American Type Culture Collection (BAA-2537), the Scottish Marine Institute's Culture Collection of Algae and Protozoa (CCAP 1431/1), and the Belgian Coordinated Collections of Microorganisms (ULC0316). The G. kilaueensis holotype has been deposited in the Algal Collection of the US National Herbarium (US# 217948). The JS1T genome sequence has been deposited in GenBank under accession number CP003587. The G+C content of the genome is 60.54 mol%. The complete genome sequence of G. kilaueensis JS1T may further understanding of cyanobacteria evolution, and the shift from anoxygenic to oxygenic photosynthesis. © 2013 Saw et al

The First Neptune Analog or Super-Earth with Neptune-like Orbit: MOA-2013-BLG-605Lb

We present the discovery of the first Neptune analog exoplanet or super-Earth with Neptune-like orbit, MOA-2013-BLG-605Lb. This planet has a mass similar to that of Neptune or a super-Earth and it orbits at $9\sim 14$ times the expected position of the snow-line, $a_{\rm snow}$, which is similar to Neptune's separation of $11\,a_{\rm snow}$ from the Sun. The planet/host-star mass ratio is $q=(3.6\pm0.7)\times 10^{-4}$ and the projected separation normalized by the Einstein radius is $s=2.39\pm0.05$. There are three degenerate physical solutions and two of these are due to a new type of degeneracy in the microlensing parallax parameters, which we designate "the wide degeneracy". The three models have (i) a Neptune-mass planet with a mass of $M_{\rm p}=21_{-7}^{+6} M_{Earth}$ orbiting a low-mass M-dwarf with a mass of $M_{\rm h}=0.19_{-0.06}^{+0.05} M_\odot$, (ii) a mini-Neptune with $M_{\rm p}= 7.9_{-1.2}^{+1.8} M_{Earth}$ orbiting a brown dwarf host with $M_{\rm h}=0.068_{-0.011}^{+0.019} M_\odot$ and (iii) a super-Earth with $M_{\rm p}= 3.2_{-0.3}^{+0.5} M_{Earth}$ orbiting a low-mass brown dwarf host with $M_{\rm h}=0.025_{-0.004}^{+0.005} M_\odot$ which is slightly favored. The 3-D planet-host separations are 4.6$_{-1.2}^{+4.7}$ AU, 2.1$_{-0.2}^{+1.0}$ AU and 0.94$_{-0.02}^{+0.67}$ AU, which are $8.9_{-1.4}^{+10.5}$, $12_{-1}^{+7}$ or $14_{-1}^{+11}$ times larger than $a_{\rm snow}$ for these models, respectively. The Keck AO observation confirm that the lens is faint. This discovery suggests that low-mass planets with Neptune-like orbit are common. So processes similar to the one that formed Neptune in our own Solar System or cold super-Earth may be common in other solar systems.Comment: 54 pages, 10 figures, 13 tables, Accepted for publication in the Ap

OGLE-2014-BLG-0289: Precise Characterization of a Quintuple-peak Gravitational Microlensing Event

We present the analysis of the binary-microlensing event OGLE-2014-BLG-0289. The event light curve exhibits five very unusual peaks, four of which were produced by caustic crossings and the other by a cusp approach. It is found that the quintuple-peak features of the light curve provide tight constraints on the source trajectory, enabling us to precisely and accurately measure the microlensing parallax πE. Furthermore, the three resolved caustics allow us to measure the angular Einstein radius θE. From the combination of πE and θE, the physical lens parameters are uniquely determined. It is found that the lens is a binary composed of two M dwarfs with masses M1 = 0.52 ± 0.04 M⊙ and M2 = 0.42 ± 0.03 M⊙ separated in projection by a⊥ = 6.4 ± 0.5 au. The lens is located in the disk with a distance of DL = 3.3 ± 0.3 kpc. The reason for the absence of a lensing signal in the Spitzer data is that the time of observation corresponds to the flat region of the light curve

Clinical presentation, auscultation recordings, ultrasonographic findings and treatment response of 12 adult cattle with chronic suppurative pneumonia: case study

Auscultation is considered the critical component of the veterinary clinical examination for the diagnosis of bovine respiratory disease but the accuracy with which adventitious sounds reflect underlying lung pathology remains largely unproven. Modern portable ultrasound machines provide the veterinary practitioner with an inexpensive, non-invasive tool with which to examine the pleural surfaces and superficial lung parenchyma. Simultaneous recording of sounds overlying normal lung and defined pathology allows critical assessment of auscultated sounds in the same animal removing confounding factors such as respiratory rate and thickness of the chest wall (body condition). Twelve cows, referred to the University of Edinburgh Veterinary School, were diagnosed with chronic suppurative pneumonia and enrolled into this prospective study to record and monitor lung sounds, ultrasonographic findings, and response to a standardised antibiotic treatment regimen. Most cows (8/12) had a normal rectal temperature on presentation but all cows had received antibiotic therapy at some time in the previous two weeks and six animals were receiving antibiotic treatment upon admission. All cattle were tachypnoeic (>40 breaths per minute) with frequent and productive coughing, halitosis, and a purulent nasal discharge most noticeable when the head was lowered. Ultrasonographic examination of the chest readily identified pathological changes consistent with severe lung pathology subsequently confirmed as chronic suppurative pneumonia in four cows at necropsy; eight cows recovered well after antibiotic treatment and were discharged two to six weeks after admission. It proved difficult to differentiate increased audibility of normal lung sounds due to tachypnoea from wheezes; coarse crackles were not commonly heard. In general, sounds were reduced in volume over consolidated lung relative to normal lung tissue situated dorsally. Rumen contraction sounds were commonly transmitted over areas of lung pathology. Trueperella (formerly Arcanobacterium) pyogenes was isolated from three of four lung tissue samples at necrospy. Treatment with procaine penicillin for 42 consecutive days resulted in marked improvement with return to normal appetite and improvement in body condition in 8 of 12 cows (67%) where lesions did not extend more than 10-15 cm above the level of the olecranon on both sides of the chest