A potato skin SSH library yields new candidate genes for suberin biosynthesis and periderm formation

Potato (Solanum tuberosum) tubers are underground storage organs covered by the skin or periderm, a suberized layer that protects inner flesh from dehydration and pathogens. Understanding the molecular processes associated with periderm formation is of great importance for a better knowledge of this protective tissue and for improving the storage life of tubers. Here, to isolate new candidate genes for potato periderm, a suppression subtractive hybridization library from potato skin was performed. This library yielded a comprehensive list of 108 candidate genes that were manually sorted in functional categories according to the main cellular and metabolic processes in periderm. As expected, the list contains Suberin and wax genes, including some genes with a demonstrated role in the biosynthesis of these cell wall aliphatic compounds. Moreover, Regulation and Stress and defence genes are highly abundant in the library in general agreement with previous potato skin proteomic studies. The putative function of the genes in periderm is discussed.     

Primary pulmonary non-Hodgkin lymphoma with myocardial infiltration

A case of primary pulmonary non-Hodgkin's lymphoma is presented. On this occasion, the lymphoma invaded the myocardium, an event which has not previously been reported in the literature. These neoplasms spread by proximity, and invasion of the pericardium, thoracic wall and oesophagus have been described. Our patient died from heart failure. Tumour myocardial infiltration may well have been the determinant cause through various mechanisms, including a decrease in myocardial contractility. Spread into the myocardium may be facilitated by bulky tumour infiltrates in the pleural space.     

Plasmids, viruses and virus-like membrane vesicles from Thermococcales

Several families of plasmids and viruses (PVs) have now been described in hyperthermophilic archaea of the order Thermococcales. One family of plasmids replicates by the rolling circle mechanism, whereas most other PVs probably replicate by the θ mode. PVs from Thermococcales encode novel families of DNA replication proteins that have only detectable homologues in other archaeal PVs. PVs from different families share a common gene pool and co-evolve with their hosts. Most Thermococcales also produce virus-like membrane vesicles similar to eukaryotic microparticles (ectosomes). Some membrane vesicles of Thermococcus nautilus harbour the plasmid pTN1, suggesting that vesicles can be involved in plasmid transfer between species.     

Whole Exome Re-Sequencing Implicates CCDC38 and Cilia Structure and Function in Resistance to Smoking Related Airflow Obstruction

Chronic obstructive pulmonary disease (COPD) is a leading cause of global morbidity and mortality and, whilst smoking remains the single most important risk factor, COPD risk is heritable. Of 26 independent genomic regions showing association with lung function in genome-wide association studies, eleven have been reported to show association with airflow obstruction. Although the main risk factor for COPD is smoking, some individuals are observed to have a high forced expired volume in 1 second (FEV₁) despite many years of heavy smoking. We hypothesised that these “resistant smokers” may harbour variants which protect against lung function decline caused by smoking and provide insight into the genetic determinants of lung health. We undertook whole exome re-sequencing of 100 heavy smokers who had healthy lung function given their age, sex, height and smoking history and applied three complementary approaches to explore the genetic architecture of smoking resistance. Firstly, we identified novel functional variants in the “resistant smokers” and looked for enrichment of these novel variants within biological pathways. Secondly, we undertook association testing of all exonic variants individually with two independent control sets. Thirdly, we undertook gene-based association testing of all exonic variants. Our strongest signal of association with smoking resistance for a non-synonymous SNP was for rs10859974 (P = 2.34×10⁻⁴) in CCDC38, a gene which has previously been reported to show association with FEV₁/FVC, and we demonstrate moderate expression of CCDC38 in bronchial epithelial cells. We identified an enrichment of novel putatively functional variants in genes related to cilia structure and function in resistant smokers. Ciliary function abnormalities are known to be associated with both smoking and reduced mucociliary clearance in patients with COPD. We suggest that genetic influences on the development or function of cilia in the bronchial epithelium may affect growth of cilia or the extent of damage caused by tobacco smoke.     

A visual test based on a freeware software for quantifying and displaying night-vision disturbances: study in subjects after alcohol consumption

Background

In this work, we propose the Halo test, a simple visual test based on a freeware software for quantifying and displaying night-vision disturbances perceived by subjects under different experimental conditions, more precisely studying the influence of the alcohol consumption on visual function.

Methods

In the Halo test, viewed on a monitor, the subject's task consists of detecting luminous peripheral stimuli around a central high-luminance stimulus over a dark background. The test, performed by subjects before and after consuming alcoholic drinks, which deteriorate visual performance, evaluates the influence that alcohol consumption exerts on the visual-discrimination capacity under low illumination conditions. Measurements were made monocularly and binocularly. Pupil size was also measured in both conditions (pre/post). Additionally, we used a double-pass device to measure objectively the optical-quality of the eye and corroborate the results from the Halo test.

Results

We found a significant deterioration of the discrimination capacity after alcohol consumption, indicating that the higher the breath-alcohol content, the greater the deterioration of the visual-discrimination capacity. After alcohol intake, the graphical results showed a greater area of undetected peripheral stimuli around the central high-luminance stimulus. An enlargement of the pupil was also observed and the optical quality of the eye was deteriorated after alcohol consumption.

Conclusions

A greater influence of halos and other night-vision disturbances were reported with the Halo test after alcohol consumption. The Halo freeware software constitutes a positive contribution for evaluating nighttime visual performance in clinical applications, such as reported here, but also in patients after refractive surgery (where halos are present) or for monitoring (time course) some ocular pathologies under pharmacological treatment.

     

Long‐term coevolution between avian brood parasites and their hosts

Coevolutionary theory predicts that the most common long‐term outcome of the relationships between brood parasites and their hosts should be coevolutionary cycles based on a dynamic change selecting the currently least‐defended host species, given that when well‐defended hosts are abandoned, hosts will be selected to decrease their defences as these are usually assumed to be costly. This is assumed to be the case also in brood parasite‐host systems. Here I examine the frequency of the three potential long‐term outcomes of brood parasite–host coevolution (coevolutionary cycles, lack of rejection, and successful resistance) in 182 host species. The results of simple exploratory comparisons show that coevolutionary cycles are very scarce while the lack of rejection and successful resistance, which are considered evolutionary enigmas, are much more frequent. I discuss these results considering (i) the importance of different host defences at all stages of the breeding cycle, (ii) the role of phenotypic plasticity in long‐term coevolution, and (iii) the evolutionary history of host selection. I suggest that in purely antagonistic coevolutionary interactions, such as those involving brood parasites and their hosts, that although cycles will exist during an intermediate phase of the interactions, the arms race will end with the extinction of the host or with the host acquiring successful resistance. As evolutionary time passes, this resistance will force brood parasites to use previously less suitable host species. Furthermore, I present a model that represents the long‐term trajectories and outcomes of coevolutionary interactions between brood parasites and their hosts with respect to the evolution of egg‐rejection defence. This model suggests that as an increasing number of species acquire successful resistance, other unparasitized host species become more profitable and their parasitism rate and the costs imposed by brood parasitism at the population level will increase, selecting for the evolution of host defences. This means that although acceptance is adaptive when the parasitism rate and the costs of parasitism are very low, this cannot be considered to represent an evolutionary equilibrium, as conventional theory has done to date, because it is not stable.     

Do climatic conditions affect host and parasite phenotypes differentially? A case study of magpies and great spotted cuckoos

Climatic conditions, through their effects on resource availability, may affect important life history strategies and trade-offs in animals, as well as their interactions with other organisms such as parasites. This impact may depend on species-specific pathways of development that differ even among species with similar resource requirements (e.g., avian brood parasites and their hosts). Here we explore the degree of covariation between environmental-climatic conditions and nestling phenotypes (i.e., tarsus length, body mass, immune response to phytohemagglutinin injection) and ectoparasite loads of great spotted cuckoos (Clamator glandarius) and those of their magpie (Pica pica) hosts, both within and among 11 study years (1997–2011). Our main results were that (1) nestling phenotypes differed among years, but differently for great spotted cuckoos and magpies; (2) nestling phenotypes showed significant among-year covariation with breeding climatic conditions (temperature and precipitation); and (3) these associations differed for cuckoos and magpies for some phenotypic traits. As the average temperature at the beginning of the breeding season (April) increased, body mass and tarsus length increased only for cuckoos, but not for magpie hosts, while immune response decreased in both species. Finally, (4) the strength of the within-year relationships between the probability of ectoparasitism by Carnus hemapterus flies and laying date (used as an estimate of the within-year variation in climatic conditions) was negatively affected by the annual accumulated precipitation in April. These results strongly suggest that variation in climatic conditions would result in asymmetric effects on different species with respect to the probability of ectoparasitism, immunity and body size. Such asymmetric effects may affect animal interactions in general and those of brood parasites and their hosts in particular.