Activation of the p38 mitogen-activated protein kinase mediates the suppressive effects of type I interferons and transforming growth factor-beta on normal hematopoiesis.

Type I interferons (IFNs) are potent regulators of normal hematopoiesis in vitro and in vivo, but the mechanisms by which they suppress hematopoietic progenitor cell growth and differentiation are not known. In the present study we provide evidence that IFN alpha and IFN beta induce phosphorylation of the p38 mitogen-activated protein (Map) kinase in CD34+-derived primitive human hematopoietic progenitors. Such type I IFN-inducible phosphorylation of p38 results in activation of the catalytic domain of the kinase and sequential activation of the MAPK-activated protein kinase-2 (MapKapK-2 kinase), indicating the existence of a signaling cascade, activated downstream of p38 in hematopoietic progenitors. Our data indicate that activation of this signaling cascade by the type I IFN receptor is essential for the generation of the suppressive effects of type I IFNs on normal hematopoiesis. This is shown by studies demonstrating that pharmacological inhibitors of p38 reverse the growth inhibitory effects of IFN alpha and IFN beta on myeloid (colony-forming granulocytic-macrophage) and erythroid (burst-forming unit-erythroid) progenitor colony formation. In a similar manner, transforming growth factor beta, which also exhibits inhibitory effects on normal hematopoiesis, activates p38 and MapKapK-2 in human hematopoietic progenitors, whereas pharmacological inhibitors of p38 reverse its suppressive activities on both myeloid and erythroid colony formation. In further studies, we demonstrate that the primary mechanism by which the p38 Map kinase pathway mediates hematopoietic suppression is regulation of cell cycle progression and is unrelated to induction of apoptosis. Altogether, these findings establish that the p38 Map kinase pathway is a common effector for type I IFN and transforming growth factor beta signaling in human hematopoietic progenitors and plays a critical role in the induction of the suppressive effects of these cytokines on normal hematopoiesis.     

Seasonal Changes in Fungal Production and Biomass on Standing Dead Scirpuslacustris Litter in a Northern Prairie Wetland

Decaying macrophytes are an important source of carbon and nutrients in fungal and bacterial communities of northern prairie wetlands. Dead macrophytes do not collapse into the water column immediately after death, and decomposition by fungi and bacteria begins while the plants are standing. The seasonal variations in fungal biomass and production on Scirpus lacustris stems, both above and below water, were measured to assess which environmental factors were dominant in affecting these variations in a typical prairie wetland. Fungal biomass and production were measured from early May to November, just prior to freeze-up. Fungal decomposition began and was greatest in the spring despite low water temperatures. The fungal production, as measured by the incorporation of [1-¹⁴C]acetate into ergosterol, ranged from 1.8 to 376 μg of C g of ash-free dry mass (AFDM)⁻¹ day⁻¹, and the biomass, as estimated by using ergosterol, ranged from nondetectable to 5.8 mg of C g of AFDM⁻¹. There was no significant difference in biomass or production between aerial and submerged portions of Scirpus stems. The water temperature was correlated with fungal production (r = 0.7, P < 0.005) for aerial stem pieces but not for submerged pieces. However, in laboratory experiments water temperature had a measurable effect on both biomass and production in submerged stem pieces. Changes in fungal biomass and productivity on freshly cut green Scirpus stems decaying in the water either exposed to natural solar radiation or protected from UV radiation were monitored over the summer. There was no significant difference in either fungal biomass (P = 0.76) or production (P = 0.96) between the two light treatments. The fungal biomass and rates of production were within the lower range of the values reported elsewhere, probably as a result of the colder climate and perhaps the lower lability of Scirpus stems compared to the labilities of the leaves and different macrophytes examined in other studies performed at lower latitudes.     

Esterase isozyme polymorphism, specific and nonspecific esterase, syngenic lines development and natural occurrence of a thermostable esterase in the tropical silkworm Bombyx mori L.

Esterase isozyme polymorphism was documented for digestive juice and haemolymph of the tropical multivoltine silkworm, Bombyx mori L., breed CB5 (GP) and its syngenic lines (CB5Lm^e-1, CB5Lm-2 and CB5Lm-5) using α- and β-naphthylacetate separately as nonspecific substrates (Ogita, Z., Kasai, T., 1965. Genetico-biochemical analysis of specific esterases in Musca domestica. Jpn. J. Genet. 40, 173–184). Polymorphism existed in the isozyme pattern of α-esterase with two or three bands in digestive juice and three to five bands in haemolymph. No polymorphism was observed in β-esterase isozyme pattern having four bands in digestive juice and two bands in haemolymph. During the course of esterase isozyme studies, the presence of some specific α-esterase bands (Est-1, 4 and 5) in haemolymph and β-esterase bands (Est-1, 2 and 3) in digestive juice were observed. But both α- and β-esterase bands Est-3 and 4 in digestive juice and Est-2 and 3 in haemolymph were found to be nonspecific. Nonspecific β-esterase band (Est-3) in haemolymph of CB5 (GP) and its syngenic lines withstood a temperature up to 80±1°C for 10 min. No thermostable band was observed in the isozyme zymogram of α-esterase in digestive juice and haemolymph or β-esterase in digestive juice. Overall, this study discusses the presence of esterase heterogeneity in the CB5 (GP) genepool, syngenic lines development, occurrence of specific α- and β-esterase bands in digestive juice and haemolymph and thermostable β-esterase band Est-3 in haemolymph in tropical silkworm Bombyx mori L.     

Seasonal variation in methane emission from a temperate Phragmites-dominated marsh: effect of growth stage and plant-mediated transport

The eddy covariance technique was employed with a tunable diode laser spectrometer to quantify methane flux from a prairie marsh dominated by Phragmites australis in north-central Nebraska, USA. The observations spanned the entire growing season (April to October) and a wide range of weather conditions, allowing a quantitative assessment of the physical and biological controls of methane emission in this ecosystem. Diel patterns in methane emission varied markedly depending on plant growth stage. Prior to plant emergence above water, the rate of methane emission from the marsh was fairly constant throughout the day. After emergence above water, there was a gradual increase in methane emission after sunrise with a peak in late afternoon. Significant changes in diel patterns were observed after tillering. Then, the diel pattern was characterized by a mid- to late-morning peak and a 2-to 4-fold increase in methane emissions from night to daytime. In early stages of plant growth, molecular diffusion through dead/live plants and the standing water column seemed to be the primary transport mechanism. After tillering, a transition occurred in the transport mechanism from a molecular diffusion to a convective throughflow, which is a rapid and active gas transport driven by pressure differences. The role of convective throughflow became less important as the plants senesced. Integrated methane emission over the six-month measurement period (April–October) was about 64 g CH₄ m^–2. On an annual basis, we estimate the annual methane emission from this ecosystem to be ≈ 80 g CH₄ m^–2 and that about 80% of the total methane emission occurred between late April and late October.     

BCR/ABL Directly Inhibits Expression of SHIP, an SH2-Containing Polyinositol-5-Phosphatase Involved in the Regulation of Hematopoiesis

The BCR/ABL oncogene causes chronic myelogenous leukemia (CML), a myeloproliferative disorder characterized by clonal expansion of hematopoietic progenitor cells and granulocyte lineage cells. The SH2-containing inositol-5-phosphatase SHIP is a 145-kDa protein which has been shown to regulate hematopoiesis in mice. Targeted disruption of the murine SHIP gene results in a myeloproliferative syndrome characterized by a dramatic increase in numbers of granulocyte-macrophage progenitor cells in the marrow and spleen. Also, hematopoietic progenitor cells from SHIP(-/-) mice are hyperresponsive to certain hematopoietic growth factors, a phenotype very similar to the effects of BCR/ABL in murine cells. In a series of BCR/ABL-transformed hematopoietic cell lines, Philadelphia chromosome (Ph)-positive cell lines, and primary cells from patients with CML, the expression of SHIP was found to be absent or substantially reduced compared to untransformed cell lines or leukemia cells lacking BCR/ABL. Ba/F3 cells in which expression of BCR/ABL was under the control of a tetracycline-inducible promoter showed rapid loss of p145 SHIP, coincident with induction of BCR/ABL expression. Also, an ABL-specific tyrosine kinase inhibitor, CGP57148B (STI571), rapidly caused reexpression of SHIP, indicating that BCR/ABL directly, but reversibly, regulates the expression of SHIP protein. The estimated half-life of SHIP protein was reduced from 18 h to less than 3 h. However, SHIP mRNA also decreased in response to BCR/ABL, suggesting that SHIP protein levels could be affected by more than one mechanism. Reexpression of SHIP in BCR/ABL-transformed Ba/F3 cells altered the biological behavior of cells in culture. The reduction of SHIP due to BCR/ABL is likely to directly contribute to the pathogenesis of CML.     

Activated brown adipose tissue releases exosomes containing mitochondrial methylene tetrahydrofolate dehydrogenase (NADP dependent) 1-like protein (MTHFD1L)

Brown adipose tissue (BAT) is a promising weapon to combat obesity and metabolic disease. BAT is thermogenic and consumes substantial amounts of glucose and fatty acids as fuel for thermogenesis and energy expenditure. To study BAT function in large human longitudinal cohorts, safe and precise detection methodologies are needed. Although regarded a gold standard, the foray of PET-CT into BAT research and clinical applications is limited by its high ionizing radiation doses. Here, we show that brown adipocytes release exosomes in blood plasma that can be utilized to assess BAT activity. In the present study, we investigated circulating protein biomarkers that can accurately and reliably reflect BAT activation triggered by cold exposure, capsinoids ingestion and thyroid hormone excess in humans. We discovered an exosomal protein, methylene tetrahydrofolate dehydrogenase (NADP⁺ dependent) 1-like (MTHFD1L), to be overexpressed and detectable in plasma for all three modes of BAT activation in human subjects. This mitochondrial protein is packaged as a cargo within multivesicular bodies of the endosomal compartment and secreted as exosomes via exocytosis from activated brown adipocytes into the circulation. To support MTHFD1L as a conserved BAT activation response in other vertebrates, we examined a rodent model and also proved its presence in blood of rats following BAT activation by cold exposure. Plasma concentration of exosomal MTHFD1L correlated with human BAT activity as confirmed by PET-MR in humans and supported by data from rats. Thus, we deduce that MTHFD1L appears to be overexpressed in activated BAT compared to BAT in the basal nonstimulated state.     

Outcomes in patients with and without disability admitted to hospital with COVID-19: a retrospective cohort study

Background:Disability-related considerations have largely been absent from the COVID-19 response, despite evidence that people with disabilities are at elevated risk for acquiring COVID-19. We evaluated clinical outcomes in patients who were admitted to hospital with COVID-19 with a disability compared with patients without a disability.Methods:We conducted a retrospective cohort study that included adults with COVID-19 who were admitted to hospital and discharged between Jan. 1, 2020, and Nov. 30, 2020, at 7 hospitals in Ontario, Canada. We compared in-hospital death, admission to the intensive care unit (ICU), hospital length of stay and unplanned 30-day readmission among patients with and without a physical disability, hearing or vision impairment, traumatic brain injury, or intellectual or developmental disability, overall and stratified by age (≤ 64 and ≥ 65 yr) using multivariable regression, controlling for sex, residence in a long-term care facility and comorbidity.Results:Among 1279 admissions to hospital for COVID-19, 22.3% had a disability. We found that patients with a disability were more likely to die than those without a disability (28.1% v. 17.6%), had longer hospital stays (median 13.9 v. 7.8 d) and more readmissions (17.6% v. 7.9%), but had lower ICU admission rates (22.5% v. 28.3%). After adjustment, there were no statistically significant differences between those with and without disabilities for in-hospital death or admission to ICU. After adjustment, patients with a disability had longer hospital stays (rate ratio 1.36, 95% confidence interval [CI] 1.19–1.56) and greater risk of readmission (relative risk 1.77, 95% CI 1.14–2.75). In age-stratified analyses, we observed longer hospital stays among patients with a disability than in those without, in both younger and older subgroups; readmission risk was driven by younger patients with a disability.Interpretation:Patients with a disability who were admitted to hospital with COVID-19 had longer stays and elevated readmission risk than those without disabilities. Disability-related needs should be addressed to support these patients in hospital and after discharge.

A successful public health response to the COVID-19 pandemic requires accurate and timely identification of, and support for, high-risk groups. There is increasing recognition that marginalized groups, including congregate care residents, racial and ethnic minorities, and people experiencing poverty, have elevated incidence of COVID-19.^1,2 Older age and comorbidities such as diabetes are also risk factors for severe COVID-19 outcomes.^3,4 One potential high-risk group that has received relatively little attention is people with disabilities.The World Health Organization estimates there are 1 billion people with disabilities globally.⁵ In North America, the prevalence of disability is 20%, with one-third of people older than 65 years having a disability.⁶ Disabilities include physical disabilities, hearing and vision impairments, traumatic brain injury and intellectual or developmental disabilities.^5,6 Although activity limitations experienced by people with disabilities are heterogeneous,^5,6 people with disabilities share high rates of risk factors for acquiring COVID-19, including poverty, residence in congregate care and being members of racialized communities.^7–9 People with disabilities may be more reliant on close contact with others to meet their daily needs, and some people with disabilities, especially intellectual developmental disabilities, may have difficulty following public health rules. Once they acquire SARS-CoV-2 infection, people with disabilities may be at risk for severe outcomes because they have elevated rates of comorbidities.¹⁰ Some disabilities (e.g., spinal cord injuries and neurologic disabilities) result in physiologic changes that increase vulnerability to respiratory diseases and may mask symptoms of acute respiratory disease, which may delay diagnosis.^11–13 There have also been reports of barriers to high-quality hospital care for patients with disabilities who have COVID-19, including communication issues caused by the use of masks and restricted access to support persons.^14–17Some studies have suggested that patients with disabilities and COVID-19 are at elevated risk for severe disease and death, with most evaluating intellectual or developmental disability.^13,18–26 Yet, consideration of disability-related needs has largely been absent from the COVID-19 response, with vaccine eligibility driven primarily by age and medical comorbidity, limited accommodations made for patients with disabilities who are in hospital, and disability data often not being captured in surveillance programs.^14–17 To inform equitable pandemic supports, there is a need for data on patients with a broad range of disabilities who have COVID-19. We sought to evaluate standard clinical outcomes in patients admitted to hospital with COVID-19²⁷ (i.e., in-hospital death, intensive care unit [ICU] admission, hospital length of stay and unplanned 30-d readmission) for patients with and without a disability, overall and stratified by age. We hypothesized that patients with a disability would have worse outcomes because of a greater prevalence of comorbidities,¹⁰ physiologic characteristics that increase morbidity risk^11–13 and barriers to high-quality hospital care.^14–17     

Conformational change in the activation of lipase: an analysis in terms of low-frequency normal modes.

The interfacial activation of Rhizomucor miehei lipase (RmL) involves the motion of an alpha-helical region (residues 82-96) which acts as a "lid" over the active site of the enzyme, undergoing a displacement from a "closed" to an "open" conformation upon binding of substrate. Normal mode analyses performed in both low and high dielectric media reveal that low-frequency vibrational modes contribute significantly to the conformational transition between the closed and open conformations. In these modes, the lid displacement is coupled to local motions of active site loops as well as global breathing motions. Atomic fluctuations of the first hinge of the lid (residues 83-84) are substantially larger in the low dielectric medium than in the high dielectric medium. Our results also suggest that electrostatic interactions of Arg86 play an important role in terms of both the intrinsic stability of the lid and its displacement, through enhancement of hinge mobility in a high dielectric medium. Additional calculations demonstrate that the observed patterns of atomic fluctuations are an intrinsic feature of the protein structure and not dependent on the nature of specific energy minima.     

Year-round observations of the net ecosystem exchange of carbon dioxide in a native tallgrass prairie

An Ameriflux site was established in mid 1996 to study the exchange of CO₂ in a native tallgrass prairie of north‐central Oklahoma, USA. Approximately the first 20 months of measurements (using eddy covariance) are described here. This prairie, dominated by warm season C4 grasses, is typical of the central Kansas/northern Oklahoma region. During the first three weeks of the measurement period (mid‐July–early August 1996), moisture‐stress conditions prevailed. For the remainder of the period (until March 1998), however, soil moisture was nonlimiting. Mid‐day net ecosystem CO₂ exchange (NEE), under well‐watered conditions, reached a maximum magnitude of 1.4 mg CO₂ m^?2 s^?1 (flux toward the surface is positive) during peak growth (mid‐July 1997), with green leaf area index of 2.8. In contrast, under moisture‐stress conditions in the same growth stage in 1996, mid‐day NEE was reduced to near‐zero. Average night NEE ranged from near‐zero, during winter dormancy, to ? 0.50 mg CO₂ m^?2 s^?1, during peak growth. Most of the variance in average night NEE was explained by changes in soil temperature (0.1 m depth) and green leaf area. The daytime NEE measurements were examined in terms of a rectangular hyperbolic relationship with incident photosynthetically active radiation. The analysis showed that the quantum yield during peak growth was similar to those measured in other prairies and the y‐intercept, so obtained, can be potentially used as an estimate of night‐time CO₂ emissions when eddy covariance data are unavailable. Daily integrated NEE reached its peak magnitude of 30.8 g CO₂ m^?2 d^?1 (8.4 g C m^?2 d^?1) in mid‐July when the green LAI was the largest (about 2.8). In general, the seasonal trend of daily NEE (on relatively clear days) followed that of green LAI. Annually integrated carbon exchange, between prescribed burns in 1997 and 1998, was 268 g C m^?2 y^?1. After incorporating carbon loss during the prescribed burn , the net annual carbon exchange in this prairie was near‐zero in 1998.