Ecology and survival of Nigritella nigra, a threatened orchid species in Scandinavia

Nigritella nigra ssp. nigra (Orchidaceae) is the only taxon of the genus in Scandinavia, where it occurs as an endemic with a disjunct distribution, mostly in upland areas of central Norway and Sweden. Nigritella nigra is a boreal-alpine, basiophilous species of open grasslands and dry fens. Both the number of localities and the number of individuals in a majority of the localities, including the study area at Sølendet, Røros, central Norway, have declined in recent decades. The most important threat is the change in agricultural practices followed by overgrowing of land earlier harvested for hay or intensively grazed. The total population of N. nigra at Sølendet is estimated to be about 3000 individuals, the largest known. Flowering individuals have been counted annually and all 225 individuals in nine permanent plots have been recorded for twenty years. The population has a large proportion of long-lived individuals with a half-life of up to 8 years in particular cohorts. Flowering behaviour varies greatly and flowering rarely occurs several years in succession. Together with the reduced size of individuals after flowering, this indicates a high cost of flowering. Correlation analyses indicate that high precipitation in autumn and winter negatively affects flowering (in July) on dry grasslands. On damp grasslands, warmth in autumn and in May of the flowering year correlates positively with flowering density. Many individuals are killed in years with heavy microtine rodent grazing. Experimental mowing as a management measure, and apparently also cattle grazing, have positive effects on the population. Some small, shallow valleys with a good supply of base-rich water on its flat, sandy floor is the main N. nigra biotopes at Sølendet.     

Effects of Targeting Herpes Simplex Virus Type 1 gD to the Endoplasmic Reticulum and trans-Golgi Network

Glycoprotein D (gD) of herpes simplex virus type 1 (HSV-1) was modified to encode targeting signals known to localize proteins to either the endoplasmic reticulum (ER) or the trans-Golgi network. These motifs conferred the predicted targeting properties on gD in transfected cells as judged by immunofluorescence staining, and the exclusion of targeted gD from the cell surface was confirmed by the fact that these molecules exhibited substantially reduced activity in cell-cell fusion assays. Recombinant viruses expressing Golgi-targeted forms of gD grew to wild-type levels in noncomplementing cells, exhibited unaltered particle/infectivity ratios, and were found to contain wild-type levels of gD, whereas a recombinant expressing ER-retained gD was helper cell dependent and, when grown on noncomplementing cells, produced virions of low specific infectivity with greatly reduced levels of gD. These data imply that HSV-1 acquires its final membrane from a post-ER compartment and lend support to the view that the virus undergoes de-envelopment and reenvelopment steps during virus egress.     

Clinical presentation and diffusion weighted MRI of acute cerebral infarction. The Bergen Stroke Study

Background

No large study has compared the yield of diffusion-weighted imaging (DWI) with clinical examination in order to differentiate lacunar stroke from other stroke subtypes. This differentiation is important for guiding further investigations and treatment.

Methods

Consecutive patients admitted with cerebral infarction were classified according to the Oxfordshire Community Stroke Project scale. Based on DWI and CT stroke was classified as lacunar (LI) and non-lacunar (NLI). Acute ischemic lesion <1.5 cm and located in subcortex or in brainstem were classified as LI. All other infarctions were classified as NLI.

Results

DWI was performed in 419 (69%) patients. Among patients with lacunar syndrome (LACS) 45 (40.5%) had NLI on DWI. All patients with total anterior syndrome (TACS) and 144 (88.3%) with partial anterior syndrome (PACS) had NLI on DWI.

Conclusion

DWI is important among patients presenting with clinical symptoms suggestive of lacunar syndrome to differentiate between LI and NLI. On the other hand, there is good correspondence between TACS or PACS and NLI on DWI.     

Improper excess light energy dissipation in Arabidopsis results in a metabolic reprogramming

Background  

Plant performance is affected by the level of expression of PsbS, a key photoprotective protein involved in the process of feedback de-excitation (FDE), or the qE component of non-photochemical quenching, NPQ.