Immunohistochemical study of the LHRH-synthesizing neuron system of aged female rats

Summary The LHRH-synthesizing neuron system was studied in young proestrous and old female rats, and in aged ovariectomized or reserpine-treated females. The medial preoptic area and septal region of old animals contains more LHRH positive perikarya compared to that of young proestrous rats. Reserpine treatment moderately increases the number of immunostainable LHRH cells, while ovariectomy is ineffective in this respect.The authors wish to thank Ms. Márta Szelier for her excellent technical assistance and Ms. Márta Soltész for the photographic work     

Plant Thin Cell Layers: A 40-Year Celebration

The concept of a thin cell layer (TCL) was initially presented by Tran Thanh Van in two key papers exactly 40 years ago. At that time, Nicotiana tabacum was the model plant used to establish three main pathways for de novo organogenesis by developing a flower, vegetative bud, and root “programme” from pedicel tissue. Over the last 40 years, a wealth of research in plant tissue culture based on TCLs has emerged, fortifying the importance of this very simple technique, and highlighting its fundamental importance as a key tool in plant cell and tissue differentiation as well as organ development. This review not only highlights the achievements made using TCLs in the plant kingdom over these 40 years, it also reports on the success of this technique in ornamentals, fruit and forestry species, vegetables, and medicinal plants. There is overwhelming evidence of the importance of this technique for plant biotechnology, and it provides one solution for the mass clonal propagation of plants, use in bioreactors, genetic transformation, or micropropagation.     

Sonication and ultrasound: impact on plant growth and development

Plant biotechnology, and plant tissue culture in particular, could benefit from new means to stimulate plant growth and development. Although the number of studies is still limited, there is evidence that sonication using low frequencies of sound (as little as a few dozen Hz) to as high as ultrasound (several dozen kHz) may increase organogenesis. In this brief review, we look at those examples in detail and explore how sound influences growth and development. Where available, we try to offer a mechanism by which sound affects or influences plant growth.     

Weak migratory connectivity,loop migration and multiple non-breeding site use in British breeding Whinchats Saxicola rubetra

Determining the links between breeding populations and the pressures, threats and conditions they experience presents a challenge for the conservation of migratory birds which can use multiple sites separated by hundreds to thousands of kilometres. Furthermore, migratory connectivity – the connections made by migrating individuals between networks of breeding and non-breeding sites – has important implications for population dynamics. The Whinchat Saxicola rubetra is declining across its range, and tracking data from a single African non-breeding site implies high migratory spread. We used geolocators to describe the migration routes and non-breeding areas of 20 Whinchats from three British breeding populations. As expected, migratory spread was high, with birds from the three populations overlapping across a wide area of West Africa. On average, in non-breeding areas, British breeding Whinchats were located 652 km apart from one another, with some likely to share non-breeding areas with individuals from breeding populations as far east as Russia. Four males made a direct non-breeding season movement to a second, more westerly, non-breeding location in January. Autumn migration was through Iberia and around the western edge of the Sahara Desert, whereas spring migration was more direct, indicating an anticlockwise loop migration. Weak migratory connectivity implies that Whinchat populations are somewhat buffered against local changes in non-breeding conditions. If non-breeding season processes have played a role in the species’ decline, then large-scale drivers are likely to be the cause, although processes operating on migration, or interactions between breeding and non-breeding processes, cannot be ruled out.     

A tightly bound chromosome antigen is detected by monoclonal antibodies in a ring-like structure on human centromeres

Monoclonal antibodies (Mabs) were raised against isolated Chinese hamster protein-depleted chromosomes Chromosome scaffolds) in order to probe for components involved in the higher-order structure of mammalian chromosomes. One of the Mabs detected a ring-like structure in metaphase at the centromere, which is conserved between Chinese hamster and human cells. Additionally, the Mab stained the centrioles in interphase cells in these two species. The antigen was enriched in chromosomal protein preparations by comparison with nuclear protein samples, and has an apparent Mr=170,000. The centromere antigen remained present in chromosome scaffold preparations, indicating that it was tightly associated with DNA. The antigen was distinct in its centromeric localisation from any of the centromere antigens reported to date. A possible role of the antigen in stabilising the centromere, by holding the sister chromatids together until their separation at the metaphase-anaphase transition is presented.     

Predicting the potential distribution and forest impact of the invasive species Cydalima perspectalis in Europe

Invasive species have considerably increased in recent decades due to direct and indirect effects of ever‐increasing international trade rates and new climate conditions derived from global change. We need to better understand how the dynamics of early species invasions develop and how these result in impacts on the invaded ecosystems. Here we studied the distribution and severe defoliation processes of the box tree moth (Cydalima perspectalis W.), a tree defoliator insect native to Asia and invasive in Europe since 2007, through the combination of species distribution models based on climate and landscape composition information. The results showed that the combination of data from the native and the invaded areas was the most effective methodology for the appropriate invasive species modeling. The species was not influenced by overall landscape factors, but only by the presence of its host plant, dispersal capacity, and climate suitability. Such climate suitability was described by low precipitation seasonality and minimum annual temperatures around 0°C, defining a continentality effect throughout the territory. We emphasize the need of studying distribution and severe defoliation processes separately because we identified that climate suitability was slightly involved in limiting species spread processes but strongly constrained ecosystem impact in terms of defoliation before the species reaches equilibrium with the new environment. New studies on habitat recovery after disturbance, ecological consequences of such impact, and community dynamics in a context of climate change are required for a better understanding of this invasive species.     

Detection and drivers of exposure and effects of pharmaceuticals in higher vertebrates

Pharmaceuticals are highly bioactive compounds now known to be widespread environmental contaminants. However, research regarding exposure and possible effects in non-target higher vertebrate wildlife remains scarce. The fate and behaviour of most pharmaceuticals entering our environment via numerous pathways remain poorly characterized, and hence our conception and understanding of the risks posed to wild animals is equally constrained. The recent decimation of Asian vulture populations owing to a pharmaceutical (diclofenac) offers a notable example, because the exposure route (livestock carcasses) and the acute toxicity observed were completely unexpected. This case not only highlights the need for further research, but also the wider requirement for more considered and comprehensive ‘ecopharmacovigilance’. We discuss known and potential high risk sources and pathways in terrestrial and freshwater ecosystems where pharmaceutical exposure in higher vertebrate wildlife, principally birds and mammals, may occur. We examine whether approaches taken within existing surveillance schemes (that commonly target established classes of persistent or bioaccumulative contaminants) and the risk assessment approaches currently used for pesticides are relevant to pharmaceuticals, and we highlight where new approaches may be required to assess pharmaceutical-related risk.     

Synthesis of orthogonally protected l-threo-β-ethoxyasparagine

Orthogonally protected l-threo-β-ethoxyasparagine (Fmoc-EtOAsn(Trt)-OH, 1) was synthesized from diethyl (2S,3S)-2-azido-3-hydroxysuccinate 2 in eight steps as a building block for solid-phase peptide synthesis. The starting material is easily available in multi-gram scale from d-diethyltartrate. The transformation steps reported here are robust and scalable. Thus, a significant amount of 1 (1.8 g) was obtained in 21% overall yield. The synthesis reported is also expected to be useful for the preparation of other O-substituted l-threo-β-hydroxyasparagine derivatives.