1. Recent declines in woodland birds in Britain have been linked to increasing habitat fragmentation. To understand the effects of fragmentation, data on avian dispersal across woodland gaps are ...essential but often lacking. 2. We used song thrush Turdus philomelos mobbing calls to attract songbirds across gaps ranging from 5 to 120 m in width and along comparable woodland edges. Responses were modelled against distance using generalized linear models. Such models have clear applied value for connecting fragmented landscapes. 3. We also calculated response indices and compared these with bird morphology. The gap-crossing results were applied to a real landscape in central Scotland and landscape metrics were calculated to judge how perception of habitat connectivity varies interspecifically. 4. The chaffinch Fringilla coelebs and the robin Erithacus rubecula both responded more readily across gaps than through woodland. There was no difference between gap and edge response for the coal tit Parus ater, while the goldcrest Regulus regulus responded more readily along edges than across gaps. Maximum gap-crossing distances ranged from 46 m (goldcrest) to 150 m (chaffinch). 5. There was a positive linear trend between mass of bird and the difference in the maximum response for gap and control experiments. Likewise there was a positive curvilinear relationship between wing area and the difference in probability of response between gap and control experiments at 50 m. These results may be interpreted in terms of manoeuvrability and ability to escape avian predation. 6. For the central Scotland landscape, the perceived number of patches in the landscape decreased exponentially with increasing gap-crossing distance, while the median patch size and mean patch fractal dimension increased linearly with gap-crossing distance. 7. Synthesis and applications. Our results show that an experimental approach using playback can be used to obtain data on avian gap crossing and the results applied to real landscapes to visualize interspecific differences in habitat perception. This has practical management applications, especially for designing forest habitat networks to maximize avian biodiversity, and potentially could help reverse the recent declines in woodland birds.
Improper management of organic waste can lead to unnecessary carbon dioxide and methane emissions, and groundwater contamination. In this study, organic waste materials from two of New Mexico’s ...(U.S.A.) top agricultural industries, pecan (Carya illinoinensis) and dairy cattle dairy manure, were used to evaluate the feasibility of an on-farm compost program. Pecan woody residues (P) served as the primary carbon source; regional cattle dairy manure (M) served as the primary nitrogen source. Additional (A) inputs from a compost consulting company (PM/A) and green waste from community landscaping and on-farm harvested legumes (PMG/A) were employed, both of which required additional labor and material inputs. Finished composts were analyzed for selected macro, secondary and micronutrients, pH, sodium adsorption ratio (SAR), electrical conductivity (EC), total carbon (TC) and organic matter (OM) content, bulk density (bd), and microbial biomass. The PM alone treatment showed similar or significantly higher amounts of macro, secondary and micronutrients compared to the PM/A and PMG/A treatments. Total microbial biomass and total salinity were highest for the PM treatment. The total cost of the PM treatment was around 1/6 of the cost of the lowest-cost addition compost production scheme, indicating that simpler, lower-input production methods may be more advantageous for on-farm compost program development.
OBJECTIVE:Activated (CD38HLA-DR) PD-1 CD4 T cells are strongly associated with virus replication and disease progression in untreated HIV-1 infection, and viral persistence in individuals on ART. Few ...studies have examined cell-associated viral load (CAVL) in different activated CD4 T-cell populations to measure relative contributions to viral reservoirs.
DESIGN:Longitudinal assessment of HIV-1 chronically infected Ugandans initiating ART, to investigate activated CD4 T-cell populations and their contribution to viral reservoirs.
METHODS:We followed 32 HIV-1 chronically infected individuals from Kampala, Uganda, and determined their CD4 T-cell counts and viral load at baseline, 6, and 12 months after the initiation of ART. T-cell populations were sorted based on activation profiles and gag DNA was measured to determine CAVL within these populations. Soluble factors associated with inflammation were measured in plasma using a multiplexed platform.
RESULTS:Concomitant with viral load decline and CD4 T-cell count rebound, the activated PD-1 CD4 T-cell population contracted upon initiation of ART. Baseline levels of activated PD-1 CD4 T cells correlated with plasma levels of IP-10 and TNFRII. Interestingly, a higher baseline level of activated PD-1 CD4 T cells was associated with poorer CD4 T-cell recovery after 12 months of ART. This population contributed significantly to the cell-associated HIV DNA load at baseline, whereas their contribution declined on ART, indicating high turnover.
CONCLUSION:Activated PD-1 CD4 T cells are predictors of poor immunologic recovery on ART and may represent a short-lived component of HIV-1 reservoirs.
Antibodies that mediate non-neutralizing functions play an important role in the immune response to Ebola virus (EBOV) and are thought to impact disease outcome. EBOV has also been associated with ...long term sequelae in survivors, however, the extent to which antibodies that mediate non-neutralizing functions are associated with the development of these sequelae is unknown. Here, the presence of antibodies mediating different effector functions and how they relate to long-term sequelae two years after the 2007 Bundibugyo Ebola virus (BDBV) outbreak was investigated. The majority of survivors demonstrated robust antibody effector functional activity and demonstrated persistent polyfunctional antibody profiles to the EBOV glycoprotein (GP) two years after infection. These functions were strongly associated with the levels of GP-specific IgG1. The odds of developing hearing loss, one of the more common sequelae to BDBV was reduced when antibodies mediating antibody dependent cellular phagocytosis (ADCP), antibody dependent complement deposition (ADCD), or activating NK cells (ADNKA) were observed. In addition, hearing loss was associated with increased levels of several pro-inflammatory cytokines and levels of these pro-inflammatory cytokines were associated with lower ADCP. These results are indicating that a skewed antibody profile and persistent inflammation may contribute to long term outcome in survivors of BDBV infection
HIV-1 infection expands large populations of late-stage differentiated CD8 T cells that may persist long after viral escape from TCR recognition. In this study, we investigated whether such CD8 T ...cell populations can perform unconventional innate-like antiviral effector functions. Chronic untreated HIV-1 infection was associated with elevated numbers of CD45RA
CD57
terminal effector CD8 T cells expressing FcγRIIIA (CD16). The FcγRIIIA
CD8 T cells displayed a distinctive transcriptional profile between conventional CD8 T cells and NK cells, characterized by high levels of
and low expression of
This transcriptional profile translated into a distinct NKp80
IL-7Rα
surface phenotype with high expression of the Helios transcription factor. Interestingly, the FcγRIIIA
CD8 T cells mediated HIV-specific Ab-dependent cellular cytotoxicity (ADCC) activity at levels comparable with NK cells on a per cell basis. The FcγRIIIA
CD8 T cells were highly activated in a manner that correlated positively with expansion of the CD8 T cell compartment and with plasma levels of soluble mediators of antiviral immunity and inflammation such as IP-10, TNF, IL-6, and TNFRII. The frequency of FcγRIIIA
CD8 T cells persisted as patients initiated suppressive antiretroviral therapy, although their activation levels declined. These data indicate that terminally differentiated effector CD8 T cells acquire enhanced innate cell-like characteristics during chronic viral infection and suggest that HIV-specific ADCC is a function CD8 T cells use to target HIV-infected cells. Furthermore, as the FcγRIIIA
CD8 T cells persist in treatment, they contribute significantly to the ADCC-capable effector cell pool in patients on antiretroviral therapy.
Acute HIV-1 infection (AHI) results in the widespread depletion of CD4
T cells in peripheral blood and gut mucosal tissue. However, the impact on the predominantly CD4
immunoregulatory invariant ...natural killer T (iNKT) cells during AHI remains unknown. Here, iNKT cells from peripheral blood and colonic mucosa were investigated during treated and untreated AHI. iNKT cells in blood were activated and rapidly depleted in untreated AHI. At the time of peak HIV-1 viral load, these cells showed the elevated expression of cell death-associated transcripts compared to preinfection. Residual peripheral iNKT cells suffered a diminished responsiveness to in vitro stimulation early into chronic infection. Additionally, HIV-1 DNA, as well as spliced and unspliced viral RNA, were detected in iNKT cells isolated from blood, indicating the active infection of these cells in vivo. The loss of iNKT cells occurred from Fiebig stage III in the colonic mucosa, and these cells were not restored to normal levels after initiation of ART during AHI. CD4
iNKT cells were depleted faster and more profoundly than conventional CD4
T cells, and the preferential infection of CD4
iNKT cells over conventional CD4
T cells was confirmed by in vitro infection experiments. In vitro data also provided evidence of latent infection in iNKT cells. Strikingly, preinfection levels of peripheral blood CD4
iNKT cells correlated directly with the peak HIV-1 load. These findings support a model in which iNKT cells are early targets for HIV-1 infection, driving their rapid loss from circulation and colonic mucosa.
Abstract
Background
Establishment of persistent human immunodeficiency virus type 1 (HIV-1) reservoirs occurs early in infection, and biomarkers of infected CD4+ T cells during acute infection are ...poorly defined. CD4+ T cells expressing the gut homing integrin complex α4β7 are associated with HIV-1 acquisition, and are rapidly depleted from the periphery and gastrointestinal mucosa during acute HIV-1 infection.
Methods
Integrated HIV-1 DNA was quantified in peripheral blood mononuclear cells obtained from acutely (Fiebig I–III) and chronically infected individuals by sorting memory CD4+ T-cell subsets lacking or expressing high levels of integrin β7 (β7negative and β7high, respectively). HIV-1 DNA was also assessed after 8 months of combination antiretroviral therapy (cART) initiated in Fiebig II/III individuals. Activation marker and chemokine receptor expression was determined for β7-defined subsets at acute infection and in uninfected controls.
Results
In Fiebig I, memory CD4+ T cells harboring integrated HIV-1 DNA were rare in both β7high and β7negative subsets, with no significant difference in HIV-1 DNA copies. In Fiebig stages II/III and in chronically infected individuals, β7high cells were enriched in integrated and total HIV-1 DNA compared to β7negative cells. During suppressive cART, integrated HIV-1 DNA copies decreased in both β7negative and β7high subsets, which did not differ in DNA copies. In Fiebig II/III, integrated HIV-1 DNA in β7high cells was correlated with their activation.
Conclusions
β7high memory CD4+ T cells are preferential targets during early HIV-1 infection, which may be due to the increased activation of these cells.
We demonstrate that memory CD4+ T cells expressing high levels of integrin β7 are enriched in total and integrated HIV-1 DNA compared to β7negative cells, and that preferential targeting of β7high cells is associated with their activation status.
In the Bay of Bengal, the warm, dry boreal spring concludes with the onset of the summer monsoon and accompanying southwesterly winds, heavy rains, and variable air–sea fluxes. Here, we summarize the ...2018 monsoon onset using observations collected through the multinational Monsoon Intraseasonal Oscillations in the Bay of Bengal (MISO-BoB) program between the United States, India, and Sri Lanka. MISO-BoB aims to improve understanding of monsoon intraseasonal variability, and the 2018 field effort captured the coupled air–sea response during a transition from active-to-break conditions in the central BoB. The active phase of the ̃20-day research cruise was characterized by warm sea surface temperature (SST > 30°C), cold atmospheric outflows with intermittent heavy rainfall, and increasing winds (from 2 to 15 m s−1). Accumulated rainfall exceeded 200 mm with 90% of precipitation occurring during the first week. The following break period was both dry and clear, with persistent 10–12 m s−1 wind and evaporation of 0.2 mm h−1. The evolving environmental state included a deepening ocean mixed layer (from ̃20 to 50 m), cooling SST (by ~1°C), and warming/drying of the lower to midtroposphere. Local atmospheric development was consistent with phasing of the large-scale intraseasonal oscillation. The upper ocean stores significant heat in the BoB, enough to maintain SST above 29°C despite cooling by surface fluxes and ocean mixing. Comparison with reanalysis indicates biases in air–sea fluxes, which may be related to overly cool prescribed SST. Resolution of such biases offers a path toward improved forecasting of transition periods in the monsoon.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Coherent quasi-elastic neutron scattering has been used to investigate the character of the rotational dynamics in the high-temperature solid phase of C60. The observed scattering can be described by ...a model in which each molecule undergoes rotational diffusion which is uncorrelated with the motions of adjacent molecules. The rotational diffusion constant D(R) is (1.4 +/-0.4) x 10 exp 10/sec at 260 K and (2.8 +/-0.8) x 10 exp 10/sec at 520 K. The temperature dependence of D(R) is consistent with a thermally activated process having an activation energy of 35 + /-15 meV. (Author)
A novel
IL4RA polymorphism, Ala57Thr, was identified in Greenlander Inuit.
We sought to determine whether the novel Thr57 allele is population specific and to assess the associations of Ala57Thr and ...Ile50Val with atopy in 2 Inuit populations.
Ala57Thr and Ile50Val were genotyped in 651 Inuit living in Denmark, 1295 Inuit living in Greenland, and 1329 individuals from 7 populations from widely differing global locations. In Inuit the polymorphisms were evaluated for associations with atopy, rhinitis, asthma, and pulmonary function.
Thr57 was in linkage disequilibrium with Ile50 (D′ = 1,
r
2
= 0.13) and was common (33%) in the Inuit but rare (<0.6%) in all other populations. In Inuit living in Denmark, the Thr57 allele (in a dose-dependent manner) and the Ile50/Thr57 haplotype were associated with lower risk of atopy (
P
linear = .003 and
P = .034, respectively), with similar trends observed for atopic rhinitis and atopic asthma. In Inuit living in Greenland, Thr57 was not associated with atopy or atopic diseases, but Ile50 was weakly associated with lower risk of atopy.
The novel
IL4RA Ala57Thr was common in and population specific to Greenlander Inuit, with Thr57 associated with a lower risk of atopy in those living in Denmark. Hence a full investigation of genotype-phenotype relationships in a given population can only be achieved if each gene is screened for novel polymorphisms in that population.
Clinical risk attributable to variations in a gene in an ethnic group requires that all variations of the gene are known for that group.
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