Mutations in RAB28, Encoding a Farnesylated Small GTPase,Are Associated with Autosomal-Recessive Cone-Rod Dystrophy

The majority of the genetic causes of autosomal-recessive (ar) cone-rod dystrophy (CRD) are currently unknown. A combined approach of homozygosity mapping and exome sequencing revealed a homozygous nonsense mutation (c.565C>T [p.Glu189^∗]) in RAB28 in a German family with three siblings with arCRD. Another homozygous nonsense mutation (c.409C>T [p.Arg137^∗]) was identified in a family of Moroccan Jewish descent with two siblings affected by arCRD. All five affected individuals presented with hyperpigmentation in the macula, progressive loss of the visual acuity, atrophy of the retinal pigment epithelium, and severely reduced cone and rod responses on the electroretinogram. RAB28 encodes a member of the Rab subfamily of the RAS-related small GTPases. Alternative RNA splicing yields three predicted protein isoforms with alternative C-termini, which are all truncated by the nonsense mutations identified in the arCRD families in this report. Opposed to other Rab GTPases that are generally geranylgeranylated, RAB28 is predicted to be farnesylated. Staining of rat retina showed localization of RAB28 to the basal body and the ciliary rootlet of the photoreceptors. Analogous to the function of other RAB family members, RAB28 might be involved in ciliary transport in photoreceptor cells. This study reveals a crucial role for RAB28 in photoreceptor function and suggests that mutations in other Rab proteins may also be associated with retinal dystrophies.     

The Failure of Intensive Self-Regulatory Treatment with Chronic Daily Headache: A Prospective Study

Sixteen patients with chronic daily headache (HA) of moderate to severe intensity received 20 sessions of self-regulatory treatment including progressive muscle relaxation, thermal biofeedback, and cognitive stress coping therapy. Four stopped treatment after 12 visits (but had received all 3 treatment components). Only 2 of 12 completers (17%) showed more than 50% reduction in HA Index based on daily diaries. Chronic daily HA continues to be relatively refractory to self-regulatory treatment.     

Some Aspects of the Importance of Genetic Diversity in Phragmites australis (Cav.) Trin. ex Steudel for the Development of Reed Stands

Various sites of Phragmites australis in Germany (Uckermark and Mark Brandenburg) and sites in Hungary and Denmark were investigated by PCR fingerprinting in order to determine their genetic diversity. Genetic similarities were calculated and, based on this, a cluster analysis was performed. The genetic similarity of reed clones around one lake ranged from between 70 to 100%, that of clones from different lakes was clearly lower. The further apart the clones were situated from each other, the less similar they were. At a wetland site near the shore a sudden colonisation by several new Phragmites clones was observed. This site was located in front of a well established genetically almost homogenous stand within the eulittoral. All the results are discussed in connection with a proposed model of establishment and development of water reed stands: colonization, selection of best adapted clones by competition and the stability of stands.     

Northern fowl mite orientation in a thermal gradient and evidence for idiothetic course control

Abstract.  The northern fowl mite, Ornithonyssus sylviarum , is an ectoparasite of birds and a poultry pest. The ability of northern fowl mites to orientate to a heat source is investigated with individual mites video-recorded in two-dimensional arenas and exposed to spatial or temporal heat gradients. Recorded tracks are digitally analysed for variation in linear velocity, mean direction of movement, and patterns in angular displacement. Mean direction of movement in a spatial gradient is significantly associated with the position of the heat source for 24/29 mites tested ( P  < 0.05), whereas most control (no heat) mean bearings are randomly distributed (16/25; P  > 0.1). Angular displacement that orientates a mite towards the heat source is positively correlated with the preceding deviation from that direction ( P  < 0.01). Angular displacement away from the heat source is random. The temporal heat gradient is such that no spatial reference to the heat source exists within the plane of the arena. Mites in an ambient (27 °C) to heated (30 °C) transition have angular displacement distributions similar to control mites (ambient to ambient transition). However, mites in a heated to ambient transition execute angular displacements approximately 25° greater than mites in the other treatments ( P  < 0.03). Mites compare the shift in temperature over time and alter their direction of movement by a programmed (idiothetic) response to a decrease in temperature, rather than through detection of the spatial position of the gradient (allothetic).     

Integrating video and genetic data to estimate annual age-structured apparent survival of American black bears

Camera or genetic data are increasingly used to estimate wildlife abundance and density. We integrated video camera data with genetic data over 7 years to estimate annual age-structured apparent survival of American black bears (Ursus americanus). We identified 70 individuals through meticulous scrutiny of 7531 video captures, cross-referenced with 721 genetic captures from hair samples concurrently collected from stations in view of cameras. We used the Cormack–Jolly–Seber model in Program Mark to estimate annual age-structured apparent survival for yearling males, yearling females, 2+ year-old males, and 2+ year-old females. We manually calculated cub survival. We compared parameter estimates based on combined video and genetic data with those based on only genetic data. Combining video and genetic data provided a means to test video-based identification accuracy, which was highest for females (97%–100%). Annual apparent survival was highest for yearling females (φ = 0.92, SE = 0.07), followed by 2+ year-old females (φ = 0.88, SE = 0.05), 2+ year-old males (φ = 0.84, SE = 0.06), and yearling males (φ = 0.80, SE = 0.14). Annual cub survival (φ = 0.86, SE = 0.07) was likely biased because we could not account for mortality that occurred in-den through early spring. Annual apparent survival and recapture probabilities derived from only genetic data were lower than those derived from combined video and genetic data. Our finding that noninvasive data can be used to estimate annual age-structured apparent survival of a species with relatively indistinct traits is broadly relevant to wildlife research and conservation.     

Long-lasting mobbing of the pied flycatcher increases the risk of nest predation

Mobbing behavior may provide real benefits because mobbing preyindividuals often cause a predator to leave the vicinity. However,mobbing calls of prey can attract acoustically oriented predatorsthus increasing nest predation. Therefore, a real value of mobbingas a type of adaptive behavior may depend on its duration. Inthis experimental study, we tested whether mobbing durationby the pied flycatcher Ficedula hypoleuca, a small hole-nestingpasserine, increases the risk of nest predation. From the topof one nest-box within each of 78 experimental plots, we playedback long calls of pied flycatchers, whereas recordings of shortmobbing calls were played back from the top of another nearbynest-box. The nest-boxes were arranged in pairs, and each ofthem contained a quail Coturnix coturnix egg. Long-call nest-boxeswere depredated by martens Martes martes significantly moreoften than short-call nest-boxes. This predator usually huntsby night and may eavesdrop on the calls of their mobbing preywhile resting nearby during the day. The results of the presentstudy show that long-lasting conspicuous mobbing calls may carrya significant cost for the breeding birds.