Peat mosses of the genus Sphagnum play a major role in global carbon storage and dominate many northern peatland ecosystems, which are currently being subjected to some of the most rapid climate ...changes on Earth.Arapidly expanding database indicates that a diverse community of microorganisms is intimately associated with Sphagnum, inhabiting the tissues and surface of the plant. Here we summarize the current state of knowledge regarding the Sphagnum microbiome and provide a perspective for future research directions. Although the majority of the microbiome remains uncultivated and its metabolic capabilities uncharacterized, prokaryotes and fungi have the potential to act as mutualists, symbionts, or antagonists of Sphagnum. For example, methanotrophic and nitrogen-fixing bacteria may benefit the plant host by providing up to 20–30% of Sphagnum carbon and nitrogen, respectively. Next-generation sequencing approaches have enabled the detailed characterization of microbiome community composition in peat mosses. However, as with other ecologically or economically important plants, our knowledge of Sphagnum–microbiome associations is in its infancy. In order to attain a predictive understanding of the role of the microbiome in Sphagnum productivity and ecosystem function, the mechanisms of plant–microbiome interactions and the metabolic potential of constituent microbial populations must be revealed.
Face masks are promoted for preventing spread of viruses; however, wearing a mask during exercise might increase CO
2
rebreathing, decrease arterial oxygenation, and decrease exercise performance. A ...systematic review and meta-analysis was conducted on the impact of wearing a mask during exercise. Data sources included SPORTDiscus, PubMed, and Medline. Eligibility criteria included all study designs comparing surgical, N95, or cloth masks to a no mask condition during any type of exercise where exercise performance and/or physiological parameters were evaluated. Healthy and clinical participants were included. Mean differences (MD) or standardized mean differences (SMD) with 95% confidence intervals were calculated and pooled effects assessed. Twenty-two studies involving 1573 participants (620 females, 953 males) were included. Surgical, or N95 masks did not impact exercise performance (SMD −0.05 −0.16, 0.07 and −0.16 −0.54, 0.22, respectively) but increased ratings of perceived exertion (SMD 0.33 0.09, 0.58 and 0.61 0.23, 0.99) and dyspnea (SMD 0.6 0.3, 0.9 for all masks). End-tidal CO
2
(MD 3.3 1.0, 5.6 and 3.7 3.0, 4.4 mm Hg), and heart rate (MD 2 0,4 beats/min with N95 masks) slightly increased. Face masks can be worn during exercise with no influences on performance and minimal impacts on physiological variables. PROSPERO registration: CRD42020224988.
Novelty:
Face masks can be worn during exercise with no impacts on performance and minimal impacts on physiological variables.
Many high-grade serous carcinomas (HGSCs) of the pelvis are thought to originate in the distal portion of the fallopian tube. Serous tubal intra-epithelial carcinoma (STIC) lesions are the putative ...precursor to HGSC and identifiable in ~ 50% of advanced stage cases. To better understand the molecular etiology of HGSCs, we report a multi-center integrated genomic analysis of advanced stage tumors with and without STIC lesions and normal tissues. The most significant focal DNA SCNAs were shared between cases with and without STIC lesions. The RNA sequence and the miRNA data did not identify any clear separation between cases with and without STIC lesions. HGSCs had molecular profiles more similar to normal fallopian tube epithelium than ovarian surface epithelium or peritoneum. The data suggest that the molecular features of HGSCs with and without associated STIC lesions are mostly shared, indicating a common biologic origin, likely to be the distal fallopian tube among all cases.High-grade serous carcinomas (HGSCs) are associated with precursor lesions (STICs) in the fallopian epithelium in only half of the cases. Here the authors report the molecular analysis of HGSCs with and without associated STICs and show similar profiles supporting a common origin for all HGSCs.
The influence of aerosol concentration on the cloud-droplet size distribution is investigated in a laboratory chamber that enables turbulent cloud formation through moist convection. The experiments ...allow steady-state microphysics to be achieved, with aerosol input balanced by cloud-droplet growth and fallout. As aerosol concentration is increased, the cloud-droplet mean diameter decreases, as expected, but the width of the size distribution also decreases sharply. The aerosol input allows for cloud generation in the limiting regimes of fast microphysics (τc
< τt
) for high aerosol concentration, and slow microphysics (τc
> τt
) for low aerosol concentration; here, τc
is the phase-relaxation time and τt
is the turbulence-correlation time. The increase in the width of the droplet size distribution for the low aerosol limit is consistent with larger variability of supersaturation due to the slow microphysical response. A stochastic differential equation for supersaturation predicts that the standard deviation of the squared droplet radius should increase linearly with a system time scale defined as
τ
s
−
1
=
τ
c
−
1
+
τ
t
−
1
, and the measurements are in excellent agreement with this finding. The result underscores the importance of droplet size dispersion for aerosol indirect effects: increasing aerosol concentration changes the albedo and suppresses precipitation formation not only through reduction of the mean droplet diameter but also by narrowing of the droplet size distribution due to reduced supersaturation fluctuations. Supersaturation fluctuations in the low aerosol/slow microphysics limit are likely of leading importance for precipitation formation.
Epigenetic mechanisms, such as DNA methylation, regulate transcriptional programs to afford the genome flexibility in responding to developmental and environmental cues in health and disease. A prime ...example involving epigenetic dysfunction is the postnatal neurodevelopmental disorder Rett syndrome (RTT), which is caused by mutations in the gene encoding methyl-CpG binding protein 2 (MeCP2). Despite decades of research, it remains unclear how MeCP2 regulates transcription or why RTT features appear 6–18 months after birth. Here we report integrated analyses of genomic binding of MeCP2, gene-expression data, and patterns of DNA methylation. In addition to the expected high-affinity binding to methylated cytosine in the CG context (mCG), we find a distinct epigenetic pattern of substantial MeCP2 binding to methylated cytosine in the non-CG context (mCH, where H = A, C, or T) in the adult brain. Unexpectedly, we discovered that genes that acquire elevated mCH after birth become preferentially misregulated in mouse models of MeCP2 disorders, suggesting that MeCP2 binding at mCH loci is key for regulating neuronal gene expression in vivo. This pattern is unique to the maturing and adult nervous system, as it requires the increase in mCH after birth to guide differential MeCP2 binding among mCG, mCH, and nonmethylated DNA elements. Notably, MeCP2 binds mCH with higher affinity than nonmethylated identical DNA sequences to influence the level of Bdnf , a gene implicated in the pathophysiology of RTT. This study thus provides insight into the molecular mechanism governing MeCP2 targeting and sheds light on the delayed onset of RTT symptoms.
Significance Decades of research have not deciphered the mechanism by which methyl-CpG binding protein 2 (MeCP2) regulates transcription and why Rett symptoms manifest 1 to 2 y after birth. We hypothesized that the temporal dynamics of MeCP2 binding might provide an answer. We developed mice with an EGFP-tagged MeCP2 allele to identify high-resolution MeCP2 binding profiles in the adult mouse brain. Using genomic binding profiles, methylation maps, and mRNA deep-sequencing data, we found MeCP2 binds to non-CG methylation (mCH, not mCG) to regulate expression of genes altered in mouse models of MeCP2 disorders. These data and the parallel timing of mCH and MeCP2 postnatal accumulation suggest MeCP2 binds mCH as neurons mature to regulate gene expression, offering an explanation for the delayed onset of Rett.
Cloud droplet size distributions (CDSDs), which are related to cloud albedo
and rain formation, are usually broader in warm clouds than predicted from
adiabatic parcel calculations. We investigate a ...mechanism for the CDSD
broadening using a moving-size-grid cloud parcel model that considers the
condensational growth of cloud droplets formed on polydisperse,
submicrometer aerosols in an adiabatic cloud parcel that undergoes vertical
oscillations, such as those due to cloud circulations or turbulence. Results
show that the CDSD can be broadened during condensational growth as a result
of Ostwald ripening amplified by droplet deactivation and reactivation, which
is consistent with early work. The relative roles of the solute effect,
curvature effect, deactivation and reactivation on CDSD broadening are
investigated. Deactivation of smaller cloud droplets, which is due to the
combination of curvature and solute effects in the downdraft region, enhances
the growth of larger cloud droplets and thus contributes particles to the
larger size end of the CDSD. Droplet reactivation, which occurs in the
updraft region, contributes particles to the smaller size end of the CDSD. In
addition, we find that growth of the largest cloud droplets strongly depends
on the residence time of cloud droplet in the cloud rather than the magnitude
of local variability in the supersaturation fluctuation. This is because the
environmental saturation ratio is strongly buffered by numerous smaller cloud
droplets. Two necessary conditions for this CDSD broadening, which generally
occur in the atmosphere, are as follows: (1) droplets form on aerosols of different
sizes, and (2) the cloud parcel experiences upwards and downwards motions.
Therefore we expect that this mechanism for CDSD broadening is possible in
real clouds. Our results also suggest it is important to consider both
curvature and solute effects before and after cloud droplet activation in a
cloud model. The importance of this mechanism compared with other mechanisms
on cloud properties should be investigated through in situ measurements and
3-D dynamic models.
Spore-producing organisms have small dispersal units enabling them to become widespread across continents. However, barriers to gene flow and cryptic speciation may exist. The common, haploid ...peatmoss Sphagnum magellanicum occurs in both the Northern and Southern hemisphere, and is commonly used as a model in studies of peatland ecology and peatmoss physiology. Even though it will likely act as a rich source in functional genomics studies in years to come, surprisingly little is known about levels of genetic variability and structuring in this species. Here, we assess for the first time how genetic variation in S. magellanicum is spatially structured across its full distribution range (Northern Hemisphere and South America). The morphologically similar species S. alaskense was included for comparison. In total, 195 plants were genotyped at 15 microsatellite loci. Sequences from two plastid loci (trnG and trnL) were obtained from 30 samples. Our results show that S. alaskense and almost all plants of S. magellanicum in the northern Pacific area are diploids and share the same gene pool. Haploid plants occur in South America, Europe, eastern North America, western North America, and southern Asia, and five genetically differentiated groups with different distribution ranges were found. Our results indicate that S. magellanicum consists of several distinct genetic groups, seemingly with little or no gene flow among them. Noteworthy, the geographical separation of diploids and haploids is strikingly similar to patterns found within other haploid Sphagnum species spanning the Northern Hemisphere. Our results confirm a genetic division between the Beringian and the Atlantic that seems to be a general pattern in Sphagnum taxa. The pattern of strong genetic population structuring throughout the distribution range of morphologically similar plants need to be considered in future functional genomic studies of S. magellanicum.
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