Are lemurs’ low basal metabolic rates an adaptation to Madagascar’s unpredictable climate?

It has been argued for nearly two decades that lemurs’ low basal metabolic rate (BMR) by comparison to other primates is an adaptation to Madagascar’s unpredictable climate. However, data from two recently published studies show that it is not just lemurs, but all strepsirrhines (the Suborder to which lemurs belong), that have low metabolic rates by comparison to other primates. Therefore, the better comparison to substantiate the argument is one with other strepsirrhines, not with all other primates. Data from the two studies do not allow the conclusion that lemurs’ BMR is lower than that of other strepsirrhines.     

‘Genetics is not the issue’: Insurers on genetics and life insurance

Valorization of knowledge has been defined as a major challenge in the context of genomics as an emerging strategic research field. Valorization is a Dutch science-policy concept for what is elsewhere called science impact or the third mission of universities. This article describes the institutionalization of valorization policy in the Dutch genomics research system as a specific manifestation of a changing social contract between science and society, which mainly targets economic value creation and the stimulation of entrepreneurship. A societal debate has emerged in which this focus on economic aspects has been strongly criticized as one-sided. In response, policy-makers are willing to adopt a broader definition of valorization. On the basis of an analysis of valorization policies and practices in Dutch medical genomics, this article draws attention to two myths in this valorization debate.     

Metabolic ‘engines’ of flight drive genome size reduction in birds

The tendency for flying organisms to possess small genomes has been interpreted as evidence of natural selection acting on the physical size of the genome. Nonetheless, the flight–genome link and its mechanistic basis have yet to be well established by comparative studies within a volant clade. Is there a particular functional aspect of flight such as brisk metabolism, lift production or maneuverability that impinges on the physical genome? We measured genome sizes, wing dimensions and heart, flight muscle and body masses from a phylogenetically diverse set of bird species. In phylogenetically controlled analyses, we found that genome size was negatively correlated with relative flight muscle size and heart index (i.e. ratio of heart to body mass), but positively correlated with body mass and wing loading. The proportional masses of the flight muscles and heart were the most important parameters explaining variation in genome size in multivariate models. Hence, the metabolic intensity of powered flight appears to have driven genome size reduction in birds.     

Population Genetic Diversity in the Australian ‘Seascape’: A Bioregion Approach

Genetic diversity within species may promote resilience to environmental change, yet little is known about how such variation is distributed at broad geographic scales. Here we develop a novel Bayesian methodology to analyse multi-species genetic diversity data in order to identify regions of high or low genetic diversity. We apply this method to co-distributed taxa from Australian marine waters. We extracted published summary statistics of population genetic diversity from 118 studies of 101 species and > 1000 populations from the Australian marine economic zone. We analysed these data using two approaches: a linear mixed model for standardised data, and a mixed beta-regression for unstandardised data, within a Bayesian framework. Our beta-regression approach performed better than models using standardised data, based on posterior predictive tests. The best model included region (Integrated Marine and Coastal Regionalisation of Australia (IMCRA) bioregions), latitude and latitude squared. Removing region as an explanatory variable greatly reduced model performance (delta DIC 23.4). Several bioregions were identified as possessing notably high genetic diversity. Genetic diversity increased towards the equator with a ‘hump’ in diversity across the range studied (−9.4 to −43.7°S). Our results suggest that factors correlated with both region and latitude play a role in shaping intra-specific genetic diversity, and that bioregion can be a useful management unit for intra-specific as well as species biodiversity. Our novel statistical model should prove useful for future analyses of within species genetic diversity at broad taxonomic and geographic scales.     

Vase life of cut rose cultivars ‘Avalanche’ and ‘Fiesta’ as affected by Nano-Silver and S-carvone treatments

Rosa hybrida L. is an important commercial cut flower. The vase life of this flower is usually short due to vascular occlusion. We assessed the effect of Nano-Silver (NS) and S-carvone in prolonging the vase life of R. hybrida L. cv. ‘Avalanche’ and ‘Fiesta’. Hence, an experiment involving the treatment with NS at 0, 50, 100, and 200 mgL^− 1 and S-carvone at 0, 0.25, 0.5, and 0.75 mgL^− 1 with 10 replicates was conducted. Applying NS pulse treatments increased vase life, water uptake rate, and fresh weight and reduced the number of bacteria, water loss, stomatal conductance and transpiration rate. However, S-carvone treatments did not have a positive effect on the vase-life parameters of cut rose flowers. NS pulse treatments increased relative fresh weight (RFW), and water uptake rate (WUR) and decreased water loss (WL) (%) by 10, 89 and 31% for cultivar ‘Avalanche’, compared to the controls, respectively. Application of 200 mgL^− 1 NS led to the highest vase life (18 days) for roses. The results show that NS increased vase life by suppressing stomatal opening, decreasing transpiration from leaves and inhibiting bacterial proliferation.     

The function of animal ‘eyespots’:Conspicuousness but not eye mimicry is key

Many animals are marked with conspicuous circular features often called 'eyespots',which intimidate predators,preventing or halting an attack.It has long been assumed that eyespots work by mimicking the eyes of larger animals,but recent experiments have indicated that conspicuousness and contrast is important in eyespot function,and not eye mimicry.We undertake two further experiments to distinguish between the conspicuousness and mimicry hypotheses,by using artificial prey presented to wild avian predators...     

The enone motif of (+)-grandifloracin is not essential for ‘anti-austerity’ antiproliferative activity

We report the synthesis and biological evaluation of three analogues of the natural product (+)-grandifloracin (+)-1. All three analogues exhibit enhanced antiproliferative activity against PANC-1 and HT-29 cells compared to the natural product. The retention of activity in an analogue lacking the enone functional group, 9, implies this structural element is not an essential part of the (+)-grandifloracin pharmacophore.     

A statistical methodology for tracking long-term change in reporting rates of birds from volunteer-collected presence–absence data

The ability to track change in biodiversity is essential to guide sustainable management and meet biodiversity monitoring, evaluation and reporting requirements, yet long-term data are usually scarce. Birds Australia has developed a simple survey methodology for use by their nationwide network of volunteers; it involves the collection of data on the presence–absence of species at repeatedly visited sites. Here we present a statistical methodology for use with these binary data to examine long-term change, using as an example records from a major bioregion of eastern Australia, 1999–2007. Regression splines were employed to model trend as a smooth nonlinear function of time within a generalised linear modelling framework. Confidence intervals based on bootstrap resampling provided a basis for assessing the significance of change, and a method was incorporated for identifying important change points in the trajectory from second derivatives of the curve. The methodology proved sensitive to change and the impact of extended dry periods was evident. The populations of several woodland species were found to be in significant decline. Two composite indices to track change common to a group of birds were developed and/or adapted from the existing literature. The results confirm the usefulness of repeated 2-ha presence–absence survey data to provide insight into patterns of long-term trends in bird populations. The statistical methodology described offers a means of tracking trends and identifying important time points and is particularly useful in situations where surveys of presence–absence of species are the most efficient way to gather long-term data.     

A case of ‘tachy-brady syndrome’: What is the mechanism?

A young male presented with incessant narrow QRS tachycardia and left ventricular dysfunction. 24-Holter monitoring revealed multiple episodes of sustained and nonsustained episodes of tachycardia with prolonged sinus pauses at termination. The analysis of the electrocardiogram, followed by an invasive electrophysiological study, suggested an unusual mechanism for this tachy-brady syndrome.     

A Sense of Belonging and Exclusion: ‘Touchability’ and ‘Untouchability’ in Tamil Nadu

In India, touch is a prime marker of status and social relations. Those who are impure are ‘untouchable’,1 The terms ‘Untouchable’ and ‘Untouchability’ have been abandoned due to the humiliating meaning these terms confer, therefore I use them in inverted commas. The politically correct and common terms today are Scheduled Castes, in short sc, or Dalits, or sometimes Harijan. I use them here synonymously. but those who are of a relatively higher purity are also, depending on the context, either ‘untouchable’ or ‘touchable’ only under certain fixed rules. In this paper, I will explore the contexts in which body contact and touch can be part of personal relations. I describe how these body contacts signify important social relations and establish community identity. Further, I will analyse how patterns of body contact on the one hand change during childhood, and on the other hand produce changes in the status of a social persona. The last point to be investigated is the meaning of touch as a sign for public representations.     

‘To be,or not to be’—The dilemma of ‘silent’ antimicrobial resistance genes in bacteria

Antimicrobial resistance is a serious threat to public health that dramatically undermines our ability to treat bacterial infections. Microorganisms exhibit resistance to different drug classes by acquiring resistance determinants through multiple mechanisms including horizontal gene transfer. The presence of drug resistance genotypes is mostly associated with corresponding phenotypic resistance against the particular antibiotic. However, bacterial communities harbouring silent antimicrobial resistance genes—genes whose presence is not associated with a corresponding resistant phenotype do exist. Under suitable conditions, the expression pattern of such genes often revert and regain resistance and could potentially lead to therapeutic failure. We often miss the presence of silent genes, since the current experimental paradigms are focused on resistant strains. Therefore, the knowledge on the prevalence, importance and mechanism of silent antibiotic resistance genes in bacterial pathogens are very limited. Silent genes, therefore, provide an additional level of complexity in the war against drug-resistant bacteria, reminding us that not only phenotypically resistant strains but also susceptible strains should be carefully investigated. In this review, we discuss the presence of silent antimicrobial resistance genes in bacteria, their relevance and their importance in public health.     

‘Selfish herds’ of guppies follow complex movement rules,but not when information is limited

Under the threat of predation, animals can decrease their level of risk by moving towards other individuals to form compact groups. A significant body of theoretical work has proposed multiple movement rules, varying in complexity, which might underlie this process of aggregation. However, if and how animals use these rules to form compact groups is still not well understood, and how environmental factors affect the use of these rules even less so. Here, we evaluate the success of different movement rules, by comparing their predictions with the movement seen when shoals of guppies (Poecilia reticulata) form under the threat of predation. We repeated the experiment in a turbid environment to assess how the use of the movement rules changed when visual information is reduced. During a simulated predator attack, guppies in clear water used complex rules that took multiple neighbours into account, forming compact groups. In turbid water, the difference between all rule predictions and fish movement paths increased, particularly for complex rules, and the resulting shoals were more fragmented than in clear water. We conclude that guppies are able to use complex rules to form dense aggregations, but that environmental factors can limit their ability to do so.     

Cardiomegaly induced by pressure overload in newborn rats is accompanied by altered expression of the long isoform of Gsα protein and deranged signaling of adenylyl cyclase

G proteins-coupled signaling pathways appear to play a role in the development of cardiac hypertrophy and its progression to heart failure. The present study aimed to investigate trimeric G proteins and adenylyl cyclase signaling in immature as well as in adult rat myocardium during this process caused by pressure overload. Pressure overload was induced in newborn (2-day-old) rats by abdominal aortic banding and myocardial preparations from left ventricular myocardium of immature (10-day-old) and adult (90-day-old) animals were analyzed for the relative content of different G protein subunits and adenylyl cyclase (AC) by immunoblotting with specific antibodies. A functional status of the AC signaling system was also evaluated. Normal maturation of rat heart was accompanied by increased expression of AC type V/VI and VII and of the long isoform (G(s)alphaL) of G(s)alpha protein. In parallel, the amounts of myocardial G(i)alpha/G(o)alpha proteins tended to decrease, and G(q)alpha/G(11)alpha and Gbeta did not change. Interestingly, whereas fluoride-stimulated AC activity increased in the course of maturation, activity of AC measured under other experimental conditions (stimulation by Mn2+, forskolin or isoproterenol) was lower in adult than in young rat myocardium. Pressure overload did not influence distribution of G proteins in immature myocardium, but considerably decreased the content of G(s)alphaL and increased G(o)alpha proteins in hearts of 90-day-old rats. These hearts exhibited worsened functional reserve as compared to age-matched controls and activity of AC was also markedly lower. A considerable reduction in Mn(2+)-stimulated AC activity together with similar decrease in AC activity determined under other stimulation conditions suggests that it is a function of AC catalytic subunit that is primarily impaired in this model of pressure overload.     

Transport and control of Ca2+ by pigeon erythrocytes. III. A ‘paradoxical’ expulsion of Ca2+ induced by a low dose of A23187 at 0° C

Pigeon erythrocytes expelled preloaded ⁴⁵Ca²⁺ in response to a low dose of A23187 at 0° C. We call this phenomenon ‘paradoxical’ expulsion. Within the first minute, 1.85 ± 0.38 μmol/l cell water was expelled; after that the internal ⁴⁵Ca²⁺ began to rise. The rises in Ca²⁺ uptake with and without A23187 addition were essentially paralleled. No premonitory rise of ⁴⁵Ca²⁺ upon the addition of A23187 was observed. Expulsion of ⁴⁵Ca²⁺ in response to A23187 was probably by the action of the Ca²⁺ pump and not by Na⁺-Ca²⁺ exchange since vanadate inhibited, but K⁺ replacement of Na⁺ in the medium had no effect. Lysophosphatidylcholine (lysoPC) caused an abrupt increase in ⁴⁵Ca²⁺ influx by cells at 0° C and was dose dependent. However, a very low dose of lysoPC induced expulsion of preloaded ⁴⁵Ca²⁺ similar to that by A23187, the response was fast and transitory, without any premonitory rise in ⁴⁵Ca²⁺ uptake. The results lend support to the suggestion that the signal to which cells respond may be a sudden change in Ca²⁺ influx per se rather than a change in internal Ca²⁺ concentration. These features of ‘paradoxical’ ⁴⁵Ca²⁺ expulsion induced by A23187 and lysoPC are not expected from mass-action equilibria but, instead, agree with the characteristics of an energy-dissipating control mechanism.     

Lys17 in the ‘lasso’ peptide lariatin A is responsible for anti-mycobacterial activity

C-terminal-lacking fragments of the anti-mycobacterial peptide lariatin A were obtained by hydrolysis using carboxypeptidase P and their anti-mycobacterial activities were evaluated. Lys17 was found to be essential for their antimicrobial activity. A molecular dynamics simulation, with explicit water molecules, helped determine the structural characteristics of Lys17 of lariatin A. The simulation revealed the dynamic formation and deformation of a salt bridge between the N_ξ atom of Lys17 and the carboxyl group of C-terminal Pro18, which is deemed to be crucial for the compound’s anti-mycobacterial activity.