Estimating dinosaur maximum running speeds using evolutionary robotics

Maximum running speed is an important locomotor parameter for many animals-predators as well as prey-and is thus of interest to palaeobiologists wishing to reconstruct the behavioural ecology of extinct species. A variety of approaches have been tried in the past including anatomical comparisons, bone scaling and strength, safety factors and ground reaction force analyses. However, these approaches are all indirect and an alternative approach is to create a musculoskeletal model of the animal and see how fast it can run. The major advantage of this approach is that all assumptions about the animal's morphology and physiology are directly addressed, whereas the exact same assumptions are hidden in the indirect approaches. In this paper, we present simple musculoskeletal models of three extant and five extinct bipedal species. The models predict top speed in the extant species with reasonably good agreement with accepted values, so we conclude that the values presented for the five extinct species are reasonable predictions given the modelling assumptions made. Improved musculoskeletal models and better estimates of soft tissue parameters will produce more accurate values. Limited sensitivity analysis is performed on key muscle parameters but there is considerable scope for extending this in the future.     

Chemoattractant-stimulated GTPase activity is decreased on membranes from polymorphonuclear leukocytes incubated in chemoattractant

Polymorphonuclear leukocytes, PMNs, incubated in a chemoattractant undergo a time-dependent decrease in responsiveness to the chemoattractant; i.e. they desensitize or adapt. We have examined the role of ligand-induced changes at early steps in signal transduction for adaptation of PMNs to chemoattractants. The chemoattractant stimulation of a pertussis toxin-sensitive GTPase activity on PMN membranes was used as an assay of signal transduction. We find a decreased basal GTPase activity and a decrease in the ability of N-formylnorleucylleucylphenylalanine (FN-LLP) to stimulate this activity on membranes prepared from PMNs incubated with the chemotactic peptide FNLLP. The basal GTPase activity is decreased by up to 70% and the peptide-stimulated GTPase activity by up to 95% on membranes from PMNs incubated for 20 min at 37 degrees C in 10(-7) M FNLLP. The decrease in peptide-stimulated GTPase activity cannot be accounted for by the decreased number of FNLLP receptors on the membranes. Rather, receptors that remain available for binding stimulate the GTPase activity with a decreased efficiency. The ligand-induced change in GTPase activity is not stimulus specific. GTPase activity stimulated by both C5a and LTB4 was decreased on membranes from PMNs incubated in FNLLP. The decrease in chemoattractant-stimulated GTPase activity is partially reversed if cells are subsequently incubated at 37 degrees C in the absence of peptide prior to membrane preparation. We detected no quantitative or qualitative change in either pertussis toxin substrates or immunoreactive G proteins when membranes from control and FNLLP-treated cells were compared.     

The polymeric hemoglobin molecule of Artemia. Interpretation of translated cDNA sequence of nine domains.

Translated cDNA for Artemia hemoglobin provided sequence data for almost nine domains, from the fourth residue of the A helix of one domain through 1405 residues to a stop codon after the ninth domain. The domain sequences were all different (homology between pairs 17-38%) but aligned well with each other and with conventional globins, satisfying the requirements for Phe at CD1, His at F8 and most other highly conserved features of globins including His at E7. Features found to be characteristic of Artemia globin and present in all nine domains were Phe at B10, Tyr at C4, Gly at F5, Phe at G5 and Gly at H22. Approximately 14 residues including a consensus -Val-Asp-Pro-Val-Thr-Gly-Leu- were available to form the linker between each pair of domains. The Artemia sequence data were compared with the crystal structures of Chironomus thummi thummi erythrocruorin III and sperm whale myoglobin in order to identify features of structural similarity and to examine the consequences of the differences. The Artemia sequences were compatible with the main helices and critical features of the globin fold. Possible modifications to the C helix, FG turn, and GH turn were studied in terms of molecular coordinates.     

2,3,4,5-Tetrahydro-1H-pyrido[2,3-b and e][1,4]diazepines as inhibitors of the bacterial enoyl ACP reductase, FabI

In the search for new antibacterial agents, the enzyme FabI has been identified as an attractive target. Employing a structure guided approach, the previously reported ene-amide series of FabI inhibitors were expanded to include 2,3,4,5-tetrahydro-1H-pyrido[2,3-b and e][1,4]diazepines. These novel series incorporate additional H-bonding functions and can be more water soluble than their naphthyridinone progenitors; diazepine 16c is shown to be efficacious in a mouse infection model.     

Paddock trees, parrots and agricultural production: An urgent need for large-scale, long-term restoration in south-eastern Australia

Summary Scattered trees, or ‘paddock trees’, are keystone structures, which provide multiple ecological values. However, they are in decline in many places. This has serious implications for species that use them, such as the vulnerable Superb Parrot (Polytelis swainsonii) of south‐eastern Australia. We outline three key aspects of the ecology, biology and distribution of the species that illustrate the implications of scattered tree decline. These are that (i) it depends on trees; (ii) it lives across agricultural landscapes; and (iii) it uses scattered tree landscapes dynamically in response to climate variation. We outline the dual challenge of maintaining populations of both scattered trees and the Superb Parrot over large scales and over the long term. Without urgent restoration action, a narrow bottleneck (where there are few mature trees) will make the long‐term future of the Superb Parrot precarious in these landscapes. We outline a vision for future landscapes that addresses this challenge, including the development of a form of Australian ‘wood‐pasture’. We suggest some ways that might be implemented at two scales. At the farm scale, we suggest (i) protecting what remnant vegetation we currently have; (ii) recruiting future large, old trees; (iii) sequentially setting aside land to ensure whole‐of‐farm tree regeneration; (iv) use of incentives to encourage restoration actions; and (v) using a revolving land fund to purchase and reorganize farms into economically and ecologically sustainable units. At the landscape scale, we suggest (i) the need for coordination of long‐term landscape restoration plans; (ii) the possible collaborative management of adjacent farms to ensure economic and ecological sustainability. We conclude that addressing the large‐scale and long‐term challenges of restoring scattered trees in landscapes occupied by the Superb Parrot could restore lost or diminished ecological services. This challenge illustrates the need for action at both the farm and the landscape scale that is planned over the short, medium and long term.     

Multilocus sequence typing of Cronobacter sakazakii and Cronobacter malonaticus reveals stable clonal structures with clinical significance which do not correlate with biotypes

Background  

The Cronobacter genus (Enterobacter sakazakii) has come to prominence due to its association with infant infections, and the ingestion of contaminated reconstituted infant formula. C. sakazakii and C. malonaticus are closely related, and are defined according their biotype. Due to the ubiquitous nature of the organism, and the high severity of infection for the immunocompromised, a multilocus sequence typing (MLST) scheme has been developed for the fast and reliable identification and discrimination of C. sakazakii and C. malonaticus strains. It was applied to 60 strains of C. sakazakii and 16 strains of C. malonaticus, including the index strains used to define the biotypes. The strains were from clinical and non-clinical sources between 1951 and 2008 in USA, Canada, Europe, New Zealand and the Far East.     

Aggregation of human serum albumin during a thermal viral inactivation step

A terminal pasteurization step has been used for some plasma-derived protein products such as human serum albumin (HSA), which consists of heating the protein in solution at 60 °C for 10 h. Native and denaturing SDS-PAGE and dynamic light scattering were used to follow the stability of HSA during this process. It appears that a thermally unstable fraction, comprised primarily of haptoglobin, is involved in the formation of soluble aggregates of HSA. Therefore, it appears that aggregation during heat treatment is not due to conformational instability of HSA itself, but arises from unfolding of a thermally labile protein impurity. As haptoglobin aggregates, it entraps some HSA, which is present at much higher concentrations. This study emphasizes that, in a complex mixture of naturally occurring proteins, one thermally labile species can trigger aggregation of more stable proteins.     

Variants in the CNR1 and the FAAH Genes and Adiposity Traits in the Community

Pharmacologic blockade of the endocannabinoid receptor 1 leads to weight loss and an improved metabolic risk profile in overweight and obese individuals. We hypothesize that common genetic variants in the CNR1 (encoding endocannabinoid receptor 1) and FAAH genes (encoding fatty acid amide hydrolase, a key enzyme hydrolyzing endocannabinoids) are associated with adiposity traits. We genotyped 18 single‐nucleotide polymorphisms (SNPs) in the CNR1 gene and 9 SNPs in the FAAH gene in 2,415 Framingham Offspring Study participants (mean age 61 ± 10 years; 52.6% women; mean BMI 28.2 ± 5.4 kg/m²; 30.3% obese) and studied them for association with cross‐sectional and longitudinal measures of adiposity (BMI, waist circumference, change over time in BMI and waist circumference, visceral and subcutaneous adipose tissue) using linear mixed‐effect models. The selected SNPs captured 85% (r² = 0.8) of the common variation (minor allele frequency >5%) at the CNR1 locus and 96% (r² = 0.8) of the common variation at the FAAH locus (defined as the genomic segment containing the gene +20 kb upstream and +10 kb downstream). After correction for multiple testing, none of the SNPs in the CNR1 gene or in the FAAH gene displayed statistical evidence for association with BMI, waist circumference, and visceral adipose tissue or subcutaneous adipose tissue (all P > 0.18). Despite comprehensive SNP mapping across the genes and their regulatory regions in a large unselected sample, we failed to find evidence for an association of common variants in the CNR1 and FAAH genes with measures of adiposity in our community‐based sample.     

Adaptive radiation of the putrid perianth: Ferraria (Iridaceae: Irideae) and its unusual pollinators

Field studies of 13 of the estimated 17 species of the southern African geophytic genus Ferraria (Iridaceae: Iridoideae) identified four distinct pollination systems. Ferraria flowers are radially symmetric and cupped with a large, mostly pale or dull-colored perianth. Perigonal nectaries secrete hexose dominant (fructose and glucose) nectar. Most species are pollinated by Diptera of four families, apparently attracted by strong floral odors, mostly putrid or fermenting, but sometimes apparently sweet, and a large perianth mottled and edged with dark color. Concentrated sugary secretions are produced on the tepal claws that form a shallow floral cup. In contrast, flowers of F. ferrariola have a deep, narrow floral cup, a pale blue or yellow perianth, and a spicy scent and are pollinated by bees in the family Apidae, rewarded by nectar of moderate sugar concentration. Ferraria divaricata and F. variabilis have dull-colored, darkly speckled or streaked perianths and produce ample, highly dilute nectar pooled at the base of the floral cup and are pollinated by eumenid and masarine wasps (Vespidae). Lastly, F. uncinata has flowers with a narrow floral cup and dull violet tepals with brown margins. They are visited only by meloid and melyrid beetles. All pollen transfers from the anther of a Ferraria flower to an insect’s body are passive, regardless of pollinator. Pollen load analyses suggests that all pollinators show a high degree of faithfulness to Ferraria flowers.