Axonal outgrowth is associated with increased ERK 1/2 activation but decreased caspase 3 linked cell death in Schwann cells after immediate nerve repair in rats

<p>Abstract</p> <p>Background</p> <p>Extracellular-signal regulated kinase (ERK1/2) is activated by nerve damage and its activation precedes survival and proliferation of Schwann cells. In contrast, activation of caspase 3, a cysteine protease, is considered as a marker for apoptosis in Schwann cells. In the present study, axonal outgrowth, activation of ERK1/2 by phosphorylation (p-ERK 1/2 ) and immunoreactivity of cleaved caspase 3 were examined after immediate, delayed, or no repair of transected rat sciatic nerves.</p> <p>Results</p> <p>Axonal outgrowth, detected by neurofilament staining, was longer after immediate repair than after either the delayed or no repair conditions. Immediate repair also showed a higher expression of p-ERK 1/2 and a lower number of cleaved caspase 3 stained Schwann cells than after delayed nerve repair. If the transected nerve was not repaired a lower level of p-ERK 1/2 was found than in either the immediate or delayed repair conditions. Axonal outgrowth correlated to p-ERK 1/2, but not clearly with cleaved caspase 3. Contact with regenerating axons affected Schwann cells with respect to p-ERK 1/2 and cleaved caspase 3 after immediate nerve repair only.</p> <p>Conclusion</p> <p>The decreased regenerative capacity that has historically been observed after delayed nerve repair may be related to impaired activation of Schwann cells and increased Schwann cell death. Outgrowing axons influence ERK 1/2 activation and apoptosis of Schwann cells.</p

Extended Averaged Learning Subspace Method for Hyperspectral Data Classification

Averaged learning subspace methods (ALSM) have the advantage of being easily implemented and appear to outperform in classification problems of hyperspectral images. However, there remain some open and challenging problems, which if addressed, could further improve their performance in terms of classification accuracy. We carried out experiments mainly by using two kinds of improved subspace methods (namely, dynamic and fixed subspace methods), in conjunction with the [0,1] and [-1,+1] normalization methods. We used different performance indicators to support our experimental studies: classification accuracy, computation time, and the stability of the parameter settings. Results are presented for the AVIRIS Indian Pines data set. Experimental analysis showed that the fixed subspace method combined with the [0,1] normalization method yielded higher classification accuracy than other subspace methods. Moreover, ALSMs are easily applied: only two parameters need to be set, and they can be applied directly to hyperspectral data. In addition, they can completely identify training samples in a finite number of iterations

2021 Taxonomic update of phylum Negarnaviricota (Riboviria: Orthornavirae), including the large orders Bunyavirales and Mononegavirales.

Correction to: 2021 Taxonomic update of phylum Negarnaviricota (Riboviria: Orthornavirae), including the large orders Bunyavirales and Mononegavirales. Archives of Virology (2021) 166:3567–3579. https://doi.org/10.1007/s00705-021-05266-wIn March 2021, following the annual International Committee on Taxonomy of Viruses (ICTV) ratification vote on newly proposed taxa, the phylum Negarnaviricota was amended and emended. The phylum was expanded by four families (Aliusviridae, Crepuscuviridae, Myriaviridae, and Natareviridae), three subfamilies (Alpharhabdovirinae, Betarhabdovirinae, and Gammarhabdovirinae), 42 genera, and 200 species. Thirty-nine species were renamed and/or moved and seven species were abolished. This article presents the updated taxonomy of Negarnaviricota as now accepted by the ICTV.This work was supported in part through Laulima Government Solutions, LLC prime contract with the US National Institute of Allergy and Infectious Diseases (NIAID) under Contract No. HHSN272201800013C. J.H.K. performed this work as an employee of Tunnell Government Services (TGS), a subcontractor of Laulima Government Solutions, LLC under Contract No. HHSN272201800013C. This work was also supported in part with federal funds from the National Cancer Institute (NCI), National Institutes of Health (NIH), under Contract No. 75N91019D00024, Task Order No. 75N91019F00130 to I.C., who was supported by the Clinical Monitoring Research Program Directorate, Frederick National Lab for Cancer Research. This work was also funded in part by Contract No. HSHQDC-15-C-00064 awarded by DHS S&T for the management and operation of The National Biodefense Analysis and Countermeasures Center, a federally funded research and development center operated by the Battelle National Biodefense Institute (V.W.); and NIH contract HHSN272201000040I/HHSN27200004/D04 and grant R24AI120942 (N.V., R.B.T.). S.S. acknowledges partial support from the Special Research Initiative of Mississippi Agricultural and Forestry Experiment Station (MAFES), Mississippi State University, and the National Institute of Food and Agriculture, US Department of Agriculture, Hatch Project 1021494. Part of this work was supported by the Francis Crick Institute which receives its core funding from Cancer Research UK (FC001030), the UK Medical Research Council (FC001030), and the Wellcome Trust (FC001030).S

2021 Taxonomic update of phylum Negarnaviricota (Riboviria: Orthornavirae), including the large orders Bunyavirales and Mononegavirales.

In March 2021, following the annual International Committee on Taxonomy of Viruses (ICTV) ratification vote on newly proposed taxa, the phylum Negarnaviricota was amended and emended. The phylum was expanded by four families (Aliusviridae, Crepuscuviridae, Myriaviridae, and Natareviridae), three subfamilies (Alpharhabdovirinae, Betarhabdovirinae, and Gammarhabdovirinae), 42 genera, and 200 species. Thirty-nine species were renamed and/or moved and seven species were abolished. This article presents the updated taxonomy of Negarnaviricota as now accepted by the ICTV

Mesozooplankton response to iron enrichment during the diatom bloom and bloom decline in SERIES (NE Pacific)

A mesoscale iron-fertilization experiment was carried out in the eastern subarctic Pacific during summer 2002. The iron patch was traced for 26 days after the enrichment, and the abundance and behavior of mesozooplankton was compared with those outside of the patch during the first half of the experiment (days 2–18) by Sastri and Dower [2006. Mesozooplankton community response during the SERIES iron enrichment experiment in the subarctic NE Pacific. Deep-Sea Research Part II.) and during the post-enrichment diatom bloom and its period of decline (days 15–26; this paper). The surface chlorophyll-a concentration in the patch was high between days 15 and 17 (6 mg m−3) and decreased to 1.4 mg m−3 at the end of the observation. Dominant zooplankton species in the upper 200 m were copepods: Eucalanus bungii, Pseudocalanus spp., Neocalanus plumchrus, N. cristatus, and Metridia pacifica. Species composition did not change significantly in the patch over the observation period. However, shallower distribution depths of E. bungii, N. cristatus and M. pacifica were observed in the patch during and after the diatom bloom. Especially, E. bungii was mainly distributed in the subsurface layer outside of the patch, but it was mainly in the surface mixed layer inside the patch, where it also had an enhanced development rate and increased biomass. We also propose the accumulation mechanism of zooplankton in the patch due to the upward immigration. Moreover, the abundance of the first copepodite stage of E. bungii and calyptopis larvae of euphausiids increased several fold in the patch compared to the densities outside the patch. The increases in both species are considered to be due to lowered mortality during the egg and naupliar stages, which was caused by lowered relative importance of eggs and nauplii in the diets of the suspension-feeding omnivores in the patch due to increased diatom abundance during the diatom bloom. Gut-pigment contents of dominant copepods in the patch increased 6–8 times, and the maximum values were observed during the bloom peak. The grazing impact on phytoplankton was low during the bloom period, but increased in the declining period of the diatom bloom

Phytoplankton community response to Fe and temperature gradients in the NE (SERIES) and NW (SEEDS) subarctic Pacific Ocean

Ship-board iron enrichment bottle experiments were carried out with samples collected at the mesoscale iron fertilization experimental site (SERIES) in the subarctic NE Pacific in the summer of 2002. Samples were collected on Day 14 of the experiment outside the patch that was in a typical high nitrate and low chlorophyll (HNLC) condition. The iron concentration in the incubation bottles ranged from 0.1 to 2.0 nM by adding FeCl3 solution. The increase in chlorophyll-a (chl-a) in the micro (>10 μm) and nano-sized (2–10 μm) fraction was observed as a function of the added iron. Chl-a in the pico-sized fraction (0.7–2 μm) showed no increase with time. Nitrate and silicate were exhausted in the Fe-amended bottles, while those in the control bottle remained at the end of incubation. The relative consumption ratio of silicate to nitrate for the control bottles was significantly higher than that for the Fe-amended bottles. As a hyperbolic relation was found between iron concentration and the rate of increase in Chl-a (specific growth rate) for the micro and nano-sized fraction, the Monod equation was fit to obtain a maximum growth rate (μmax) and a half-saturation constant for iron (KFe). The μmax values were 0.72 and 0.48 d−1 for the micro and nano-sized fraction, respectively. The KFe values were 0.10 and 0.08 nM for the micro and nano-sized fraction, respectively. The μmax agreed with the rate of increase in Chl-a observed in situ for the mesoscale iron fertilization experiment. The μmax value for micro-sized fraction at 12 °C was half of that in the western subarctic Pacific Ocean (SEEDS experiment in 2001), indicating the Chl-a increase rate (potential growth rate) after iron enrichment was much higher in SEEDS than that in SERIES. The KFe values were much lower than that in SEEDS, suggesting that the phytoplankton community in the NE subarctic Pacific Ocean acclimates to a lower ambient Fe concentration. This difference in KFe between SERIES (NE) and SEEDS (NW) may reflect the previously suggested gradient in Fe flux to the subarctic Pacific Ocean. A temperature gradient was also applied to investigate the effect of temperature on the growth response of the phytoplankton community. No obvious effect of temperature increase to 16 °C was found in SERIES, while μmax and KFe changed significantly with temperature in SEEDS