Population ecology of Trituras cristatus and T. vulgaris (Urodela) in SW Sweden

The population ecology of newts was investigated between 1969 and 1974 in two localities near Gothenburg, SW Sweden: the Gunnebo park pond (about 300 m²) where Triturus cristatus Laurenti and T. vulgaris L. are sympatric, and a rock-pool (6 m²) in Billdal with only T. vulgaris. At Gunnebo, a population of about 350 breeding T. cristatus was found with about as many males as females but males being more aquatic than females. An annual survival of 0.7–0.8 was estimated for the adults. The T. vulgaris population at the same locality was estimated to about 250–300 breeding adults with a sex ratio possibly in favour of males. The survival of adults was found to be extremely low and a very small percent of the adults seems to breed more than once. The Billdal T. vulgaris population was estimated to contain nearly 70 breeding adults with a sex ratio very near to 1:1. The annual survival of adults was found to be 0.5. The different survival of the two T. vulgaris populations are discussed with particular reference to predation. The age at which newts breed for the first time seems to vary; for T. vulgaris five years may well be the normal age. Factors that may limit the sizes of the populations, possible reasons for differences in frequency of occurrence in water, and possible predators are discussed.     

Defensive and secondary metabolism in plant tissue cultures,with special reference to nicotinamide,glutathione and oxidative stress

The purpose of the presentation is to interconnect and illuminate certain parts of metabolism regarding stress signalling and defensive functions, including secondary metabolism in intact plants and plant tissue cultures. Increased cell/tissue levels of reactive oxygen species like H₂O₂, O₂ ^- and ·OH and the metabolism of glutathione, are linked to defensive/secondary metabolism and tissue differentiation. Special attention is paid to nicotinamide. A hypothetical role of nicotinamide and its metabolites as stress signals is also put forward especially in connection with hypomethylation of DNA. A role of DNA hypomethylation, as a link between various types of stressors and the induction of plant devensive metabolism, is discussed. We suggest that nicotinamide or nicotinamide based substances may be of value within biotechnology for the production of valuable substances as well as for plant protection.Abbreviations BSO buthionine sulfoximine - CHS chalcone synthase - GSH reduced glutathione - GSSG oxidized glutathione - INA isonicotinic acid - NIC nicotinamide - PADPRP poly(ADP-ribose)polymerase - PAL phenylalanine ammonia-lyase - SA salicylic acid - SAM S-adenosylmethionine - SSB single strand breakage     

Simple ways to measure behavioral responses of Drosophila to stimuli and use of these methods to characterize a novel mutant

The behavioral responses of adult Drosophila fruit flies to a variety of sensory stimuli--light, volatile and non-volatile chemicals, temperature, humidity, gravity, and sound--have been measured by others previously. Some of those assays are rather complex; a review of them is presented in the Discussion. Our objective here has been to find out how to measure the behavior of adult Drosophila fruit flies by methods that are inexpensive and easy to carry out. These new assays have now been used here to characterize a novel mutant that fails to be attracted or repelled by a variety of sensory stimuli even though it is motile.     

LYP inhibits T-cell activation when dissociated from CSK

Lymphoid tyrosine phosphatase (LYP) and C-terminal Src kinase (CSK) are negative regulators of signaling mediated through the T-cell antigen receptor (TCR) and are thought to act in a cooperative manner when forming a complex. Here we studied the spatiotemporal dynamics of the LYP-CSK complex in T cells. We demonstrate that dissociation of this complex is necessary for recruitment of LYP to the plasma membrane, where it downmodulates TCR signaling. Development of a potent and selective chemical probe of LYP confirmed that LYP inhibits T-cell activation when removed from CSK. Our findings may explain the reduced TCR-mediated signaling associated with a single-nucleotide polymorphism that confers increased risk for certain autoimmune diseases, including type 1 diabetes and rheumatoid arthritis, and results in expression of a mutant LYP that is unable to bind CSK. Our compound also represents a starting point for the development of a LYP-based treatment of autoimmunity.     

Magnetite nanoparticles can be coupled to microbubbles to support multimodal imaging

Microbubbles (MBs) are commonly used as injectable ultrasound contrast agent (UCA) in modern ultrasonography. Polymer-shelled UCAs present additional potentialities with respect to marketed lipid-shelled UCAs. They are more robust; that is, they have longer shelf and circulation life, and surface modifications are quite easily accomplished to obtain enhanced targeting and local drug delivery. The next generation of UCAs will be required to support not only ultrasound-based imaging methods but also other complementary diagnostic approaches such as magnetic resonance imaging or computer tomography. This work addresses the features of MBs that could function as contrast agents for both ultrasound and magnetic resonance imaging. The results indicate that the introduction of iron oxide nanoparticles (SPIONs) in the poly(vinyl alcohol) shell or on the external surface of the MBs does not greatly decrease the echogenicity of the host MBs compared with the unmodified one. The presence of SPIONs provides enough magnetic susceptibility to the MBs to accomplish good detectability both in vitro and in vivo. The distribution of SPIONs on the shell and their aggregation state seem to be key factors for the optimization of the transverse relaxation rate.     

Clinical Guidelines for Management of Bone Health in Rett Syndrome Based on Expert Consensus and Available Evidence

Objectives

We developed clinical guidelines for the management of bone health in Rett syndrome through evidence review and the consensus of an expert panel of clinicians.

Methods

An initial guidelines draft was created which included statements based upon literature review and 11 open-ended questions where literature was lacking. The international expert panel reviewed the draft online using a 2-stage Delphi process to reach consensus agreement. Items describe the clinical assessment of bone health, bone mineral density assessment and technique, and pharmacological and non-pharmacological interventions.

Results

Agreement was reached on 39 statements which were formulated from 41 statements and 11 questions. When assessing bone health in Rett syndrome a comprehensive assessment of fracture history, mutation type, prescribed medication, pubertal development, mobility level, dietary intake and biochemical bone markers is recommended. A baseline densitometry assessment should be performed with accommodations made for size, with the frequency of surveillance determined according to individual risk. Lateral spine x-rays are also suggested. Increasing physical activity and initiating calcium and vitamin D supplementation when low are the first approaches to optimizing bone health in Rett syndrome. If individuals with Rett syndrome meet the ISCD criterion for osteoporosis in children, the use of bisphosphonates is recommended.

Conclusion

A clinically significant history of fracture in combination with low bone densitometry findings is necessary for a diagnosis of osteoporosis. These evidence and consensus-based guidelines have the potential to improve bone health in those with Rett syndrome, reduce the frequency of fractures, and stimulate further research that aims to ameliorate the impacts of this serious comorbidity.     

Plankton community composition and vertical migration during polar night in Kongsfjorden

The polar night in the Arctic is characterized by up to six months of darkness, low temperatures and limited food availability. Biological data on species composition and abundance during this period are scarce due to the logistical challenges posed when sampling these regions. Here, we characterize the plankton community composition during the polar night using water samplers and zooplankton net samples (50, 64, 200, 1500 μm), supplemented by acoustics (ADCPs, 300 kHz), to address a previously unresolved question–which species of zooplankton perform diel vertical migration during the polar night? The protist community (smallest plankton fraction) was mainly represented by ciliates (Strombidiida). In the larger zooplankton fractions (50, 64, 200 μm) the species composition was represented primarily by copepod nauplii and small copepods (e.g., Microcalanus spp., Pseudocalanus spp. and Oithona similis). In the largest zooplankton fraction (>1500 μm), the euphausiid, Thysanoessa inermis, was the most abundant species followed by the chaetognath Parasagitta elegans. Classical DVM was not observed throughout the darkest parts of the polar night (November–mid-January), although, subtle vertical migration patterns were detected in the acoustic data. With the occurrence of a more distinct day–night cycle (i.e., end of January), acoustical DVM signals were observed, paralleled by a classical DVM pattern in February in the largest fractions of zooplankton net samples. We suggest that Thysanoessa spp. are main responsible for the acoustical migration patterns throughout the polar night, although, chaetognaths and copepods may be co-responsible.