Responses of neurons of the anterodorsal nucleus of the thalamus and comparative analysis of 3 limbic nuclei

Comparison of the three limbic thalamic nucleic shows that in spite of some common features of organization and connections, these nuclei presumably play different functional roles. N. AV may be regarded as an important "on-line" functional link of the limbic circuit. N. AD, possibly serves as input from the specific auditory structures to the limbic system. N. AM may participate in regulation of the general level of activity together with unspecific thalamic nuclei.     

PERMEABILITY OF MUSCLE CAPILLARIES TO EXOGENOUS MYOGLOBIN

Whale skeletal muscle myoglobin (mol wt 17,800; molecular dimensions 25 x 34 x 42 Å) was used as a probe molecule for the pore systems of muscle capillaries. Diaphragms of Wistar-Furth rats were fixed in situ at intervals up to 4 h after the intravenous injection of the tracer, and myoglobin was localized in the tissue by a peroxidase reaction. Gel filtration of plasma samples proved that myoglobin molecules remained in circulation in native monomeric form. At 30–35 s postinjection, the tracer marked ~75% of the plasmalemmal vesicles on the blood front of the endothelium, 15% of those located inside and none of those on the tissue front. At 45 s, the labeling of vesicles in the inner group reached 60% but remained nil for those on the tissue front. Marked vesicles appeared on the latter past 45 s and their frequency increased to ~80% by 60–75 s, concomitantly with the appearance of myoglobin in the pericapillary spaces. Significant regional heterogeneity in initial labeling was found in the different segments of the endothelium (i.e., perinuclear cytoplasm, organelle region, cell periphery, and parajunctional zone). Up to 60 s, the intercellular junctions and spaces of the endothelium were free of myoglobin reaction product; thereafter, the latter was detected in the distal part of the intercellular spaces in concentration generally equal to or lower than that prevailing in the adjacent pericapillary space. The findings indicate that myoglobin molecules cross the endothelium of muscle capillaries primarily via plasmalemmal vesicles. Since a molecule of this size is supposed to exit through both pore systems, our results confirm the earlier conclusion that the plasmalemmal vesicles represent the large pore system; in addition, they suggest that the same structures are, at least in part, the structural equivalent of the small pore system of this type of capillaries.     

Neolignans from an Aniba species

A benzene extract of the trunk wood of an Aniba species contained 3a-allyl-2-aryl-5-methoxy-3-methyl-2,3,3a,6-tetrahydro-6-oxobenzofurans which may be responsible, through sequential Cope, retro-Claisen and Claisen rearrangements respectively for the formation of the co-occurring 5-allyl-2-aryl-5-methoxy-3-methyl-2,3,5,6-tetrahydro-6-oxobenzofurans; the 6-O-allyl-2-aryl-5-methoxy-3-methyl-2,3-dihydrobenzofurans and the 7-allyl-2-aryl-6-hydroxy-5-methoxy-3-methyl-2,3-dihydrobenzofurans. The examination of the stereochemistry of these products led to the formulation of burchellin, previously isolated from Aniba burchellii Kostermans, as (2S,3S,3aR)-3a-allyl-5-methoxy-2-piperonyl-3-methyl-2,3,3a,6-tetrahydro-6-oxobenzofuran. The structure 1-allyl-4,8-dihydroxy-7-(3-methoxy-4,5-methylenedioxyphenyl)-6-methyl-3-oxobicyclo[3,2,1]octane is tentatively proposed for an additional neolignan.     

The theta modulation of rabbit hippocampal neurons and its correlation with other indices of spontaneous and evoked activity]

Reliability of the existing functional criteria for differentiation of pyramidal ("complex spike neurones") and inhibitory ("theta neurones") cells in the hippocampus of waking rabbit is evaluated on the basis of statistical analysis of neuronal spontaneous and evoked activity. The analysis shows, that the criteria of mean frequency, presence of theta modulation, neuronal behaviour in situations provoking EEG theta rhythm (e.g., excitation or inhibition during presentation of sensory stimuli), effects of medial septum and intrahippocampal stimulation do not permit reliable identification of the hippocampal neuronal types in the waking rabbit. The data on functional classification of the hippocampal neurones are discussed in connection with existing suggestions about their state in situations inducing theta rhythm generation.     

Ecosystem quality in LCIA: status quo,harmonization, and suggestions for the way forward

Purpose

Life cycle impact assessment (LCIA) results are used to assess potential environmental impacts of different products and services. As part of the UNEP-SETAC life cycle initiative flagship project that aims to harmonize indicators of potential environmental impacts, we provide a consensus viewpoint and recommendations for future developments in LCIA related to the ecosystem quality area of protection (AoP). Through our recommendations, we aim to encourage LCIA developments that improve the usefulness and global acceptability of LCIA results.

Methods

We analyze current ecosystem quality metrics and provide recommendations to the LCIA research community for achieving further developments towards comparable and more ecologically relevant metrics addressing ecosystem quality.

Results and discussion

We recommend that LCIA development for ecosystem quality should tend towards species-richness-related metrics, with efforts made towards improved inclusion of ecosystem complexity. Impact indicators—which result from a range of modeling approaches that differ, for example, according to spatial and temporal scale, taxonomic coverage, and whether the indicator produces a relative or absolute measure of loss—should be framed to facilitate their final expression in a single, aggregated metric. This would also improve comparability with other LCIA damage-level indicators. Furthermore, to allow for a broader inclusion of ecosystem quality perspectives, the development of an additional indicator related to ecosystem function is recommended. Having two complementary metrics would give a broader coverage of ecosystem attributes while remaining simple enough to enable an intuitive interpretation of the results.

Conclusions

We call for the LCIA research community to make progress towards enabling harmonization of damage-level indicators within the ecosystem quality AoP and, further, to improve the ecological relevance of impact indicators.

     

Edge effects on small mammals: Differences between arboreal and ground‐dwelling species living near roads in Brazilian fragmented landscapes

Habitat fragmentation often induces edge effects that can increase, decrease or have minimal effect upon the population density of a species, depending upon environmental conditions and the requirements of the species. Using a trapping study and generalized linear mixed models, we evaluated edge effects on small tropical mammals living near roads, including two ground‐dwelling (Akodon sp. and Cerradomys subflavus) and two arboreal (Marmosops incanus and Rhipidomys sp.) species. We examined the relationship of these edge effects to environmental factors at both plot and patch scales. Generalist ground‐dwelling species were attracted to edges, with higher population densities recorded in habitats close to road or matrix edges where vegetation density was lower. In contrast, populations of the generalist arboreal species avoided edge habitats, their populations were found in greater density in habitats far from roads/matrix edges. Thus, our results show that patterns of edge habitat utilization were related to the ecological requirements of each species. These findings are especially important in the tropics, where demand for economic growth in many countries has accelerated the fragmentation process and has recently culminated in increased road construction and expansion. Fragmented habitats promote an increase in edge environments, and consequently will reduce the abundance of arboreal small mammal species, such as those used as models in this study.     

CRISPR Screens Uncover Genes that Regulate Target Cell Sensitivity to the Morphogen Sonic Hedgehog

1. Download high-res image (232KB)
2. Download full-size image