Microfossil assemblages that include large acritarchs with complex processes, known as Doushantuo-Pertatataka-type acritarchs, are recovered from early Ediacaran successions globally. They are ...commonly found in shale and chert lithologies, but their diversity and palaeobiological significance is greatest when they are phosphatized. The best-known examples are from the Doushantuo Formation, South China, which preserves over 60 taxa including possible embryonic forms which may represent the oldest fossil animals. Fossils have only been recorded in four Ediacaran phosphorite deposits. Here we report the fifth such occurrence, from phosphorites of the upper Khesen Formation, Khuvsgul Group, northern Mongolia, where preservation rivals that in the Doushantuo Formation. The assemblage includes the likely cyanobacteria Obruchevella delicata, O. magna, O. parvissima and O. valdaica, as well as various Siphonophycus filaments, the possible alga Archaeophycus yunnanensis, and the Doushantuo-Pertatataka-type acritarchs Appendisphaera grandis, A. fragilis, A. tenuis, Cavaspina basiconica, Variomargosphaeridium gracile and V. aculeiparvum, sp. nov. The phosphorites also preserve the multicellular embryo-like taxon Megasphaera, which is represented by M. minuscula sp. nov. and potentially by M. puncticulosa. Geological and chemostratigraphical data suggest a latest Ediacaran age for the Khesen assemblage, immediately prior to the Proterozoic-Phanerozoic boundary. Thus, this is the youngest Doushantuo-Pertatataka-type microfossil assemblage yet described. It extends the range of Appendisphaera, Cavaspina, Megasphaera and Variomargosphaeridium upward by tens of millions of years. The assemblage adds to a growing database of Ediacaran fossils and emphasizes the importance of Mongolian strata to understanding the transition from a broadly microbial Proterozoic Eon to a Phanerozoic Eon where macroscopic animals acted as geobiological agents.
Background
The natural history of multiple sclerosis (MS) typically presents with the clinically isolated syndrome (CIS), an episode of neurological symptoms caused by central nervous system ...inflammation or demyelination that does not fulfil the diagnostic criteria for MS.
Objective
As preclinical studies have suggested that exposure to ultraviolet radiation (UVR) could regulate the development of MS, the Phototherapy for CIS (PhoCIS trial) was established to examine the effects of narrowband UVB phototherapy on patients with CIS, and their conversion to MS.
Methods
Of the 20 participants, half received 24 sessions of narrowband UVB exposure over eight weeks; participants in both arms were followed for 12 months. All participants were supplemented to 25-hydroxyvitamin D3 levels of >80 nmol/l.
Results
By 12 months, 100% of those in the no phototherapy arm and 70% in the phototherapy arm had converted to MS, although this difference was not statistically significant.
Conclusion
This study provides a basis for further studies to determine if there are any benefits of the therapeutic effects of narrowband UVB radiation on MS progression.
The etiology of asthma, a chronic inflammatory disorder of the airways, remains obscure, although T cells appear to be central disease mediators. Lyn tyrosine kinase has been implicated as both a ...facilitator and inhibitor of signaling pathways that play a role in allergic inflammation, although its role in asthma is unclear because Lyn is not expressed in T cells. We show in the present study that Lyn-/- mice develop a severe, persistent inflammatory asthma-like syndrome with lung eosinophilia, mast cell hyperdegranulation, intensified bronchospasm, hyper IgE, and Th2-polarizing dendritic cells. Dendritic cells from Lyn-/- mice have a more immature phenotype, exhibit defective inhibitory signaling pathways, produce less IL-12, and can transfer disease when adoptively transferred into wild-type recipients. Our results show that Lyn regulates the intensity and duration of multiple asthmatic traits and indicate that Lyn is an important negative regulator of Th2 immune responses.
Abstract
We present early observations and analysis of the double-peaked Type IIb supernova (SN IIb) SN 2021zby. TESS captured the prominent early shock-cooling peak of SN 2021zby within the first ...∼10 days after explosion with a 30 minute cadence. We present optical and near-infrared spectral series of SN 2021zby, including three spectra during the shock-cooling phase. Using a multiband model fit, we find that the inferred properties of its progenitor are consistent with a red supergiant or yellow supergiant, with an envelope mass of ∼0.30–0.65
M
⊙
and an envelope radius of ∼120–300
R
⊙
. These inferred progenitor properties are similar to those of other SNe IIb with a double-peaked feature, such as SNe 1993J, 2011dh, 2016gkg, and 2017jgh. This study further validates the importance of the high cadence and early coverage in resolving the shape of the shock-cooling light curve, while the multiband observations, particularly UV, are also necessary to fully constrain the progenitor properties.
Within Syngnathidae (pipefish, seadragons and seahorses), male pregnancy often results in choosy males and competitive females. Females in these species often evolve secondary sexual traits and ...engage in courtship displays that make their ornaments more noticeable to males. Most syngnathids probably continue to grow larger throughout their lives, but we know little about the relationship between age and mating competition in these taxa. Here, we use the Gulf pipefish, Syngnathus scovelli, to investigate the roles of ornament size, courtship activity level, age and fecundity in female mating competition. We conducted male choice trials that allowed males to choose between similarly sized females of different ages. We also measured age and size at maturity. We found that females with larger ornaments were deeper bodied and engaged in longer courtship displays, yet males chose females based on body depth and display rather than ornamentation. This result suggests that ornamentation serves to help males assess female quality. Female age plays no role in male choice or in female ornamentation. Our finding that males care more about female phenotype than female age considerably simplifies the interpretation of mating patterns in natural populations of Gulf pipefish, which are characterized by considerable age structure.
•We investigated factors influencing male choice in S. scovelli.•Males chose females based on body depth and display rather than ornamentation.•Female ornamentation was correlated with female body size, fecundity and courtship.•Female age did not affect mate choice, female fecundity, ornamentation or courtship.•Faster growth in females had no impact on any of the tested traits.
Development of multiple sclerosis (MS) is frequently preceded by an acute or subacute neurological disturbance referred to as clinically isolated syndrome (CIS). The specific immunological ...disturbances present in CIS remain underexamined. This study analysed peripheral blood mononuclear cells from n=18 treatment‐naive individuals with recently diagnosed CIS (<120 days) for disturbances in the phenotype of T regulatory (Treg), follicular T regulatory (Tfr), T helper (Th), follicular T helper (Tfh) and B cells. Relative to healthy controls (n=19), CIS was associated with lower proportions of suppressive CD45RA+FoxP3lo Treg and Tfr cells and greater proportions of non‐suppressive CD45RA−FoxP3lo and Th17‐like Treg and Tfr. Lower Helios expression (mean fluorescence intensity) was measured across all Treg and Tfr fractions in the CIS group, suggesting less potent regulatory function. Greater frequencies of activated, efficient B‐cell helper Tfh subsets and a trend for a higher proportion of IgD−CD27− B cells was also detected in the CIS group, characteristics that were positively correlated with Treg and Tfr Helios expression. These results indicate that Treg and Tfr impairment is an early feature in MS.
Neurology: Changes in T cells precede multiple sclerosis
Neurological attacks that commonly precede multiple sclerosis are associated with impairment of the immune system's T cells. A team led by Prue Hart from the Telethon Kids Institute at the University of Western Australia in Perth characterized the immune cells in the blood from 18 people who had been recently diagnosed with clinically isolated syndrome (CIS), a condition that often leads to multiple sclerosis, and 19 healthy controls. Looking at a subpopulation of immune‐modulating cells known as regulatory T cells, the researchers found that patients with CIS had lower levels of the kind that suppress immune responses and higher levels of the kind that induce inflammation. The regulatory T cells also showed molecular signs of dysfunction, as did B cells from CIS patients. The findings highlight several immune aberrations that could be targeted to halt the course of the disease.
Summary
Background
The molecular determinants of the severity and persistence of allergic asthma remain poorly understood. Suppressor of cytokine signalling 1 (SOCS1) is a negative regulator of ...IL‐4‐dependent pathways in vitro and might therefore control T‐helper type 2 (Th2) immunity associated traits, such as IgE levels, mucin production, IL‐5 and IL‐13 induction, and eosinophilic mucosal inflammation, which are implicated in allergic asthma.
Objective
To investigate the role of SOCS1 in regulating Th2‐associated disease traits in a murine sub‐chronic aeroallergen‐driven asthma model.
Methods
Following sensitization and challenge with ovalbumin (OVA), bronchoalveolar lavage and serum were collected from mice lacking the Socs1 gene on an IFN‐γ null background (Socs1−/−Ifnγ−/−). The composition of infiltrating cells in the lung, serum IgE and IgG1 levels and cytokine levels were analysed.
Results
Serum IgE levels and infiltrating eosinophils were considerably increased in the lungs of OVA‐treated Socs1−/−Ifnγ−/− mice compared with Ifnγ−/− and C57BL/6 controls. Expression of the Th2 cytokines, IL‐4, IL‐5 and IL‐13 was increased in CD4+ cells and lung tissue from OVA‐treated Socs1−/−Ifnγ−/− mice. IgE, IL‐5 levels and infiltrating eosinophils were also elevated in saline‐treated Socs1−/−Ifnγ−/− mice, suggesting that in the absence of SOCS1, mice are already biased towards a Th2 response. It is at present unclear whether the elevated cytokine levels are sufficient to result in the exacerbated Th2 response to OVA challenge or whether enhanced intra‐cellular signalling also contributes. Surprisingly, of the various IL‐4/IL‐13 responsive genes tested, only Arginase I appeared to be modestly up‐regulated in the lungs of OVA‐treated Socs1−/−Ifnγ−/− mice, suggesting that regulation by SOCS1 occurs primarily in haematopoietic cells and not in the airway epithelium.
Conclusions
Together these results indicate that SOCS1 is an important regulator of the Th2 response.
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