Flowering plants predominantly conduct water in tubes known as vessels, with vessel diameter playing a crucial role in plant adaptation to climate and reactions to climate change. The importance of ...vessels makes it essential to understand how and why vessel diameter, plant height, and other ecological factors are interrelated. Although shoot length is by far the main driver of variation in mean vessel diameter across angiosperms, much remains to be understood regarding the factors accounting for the abundant variation around the y-axis in plots of mean species vessel diameter against shoot length. Here, we explore the potential role of porosity types, wood density, leaf phenology, background imperforate tracheary element type, vasicentric tracheids, vascular tracheids, perforation plate type, and successive cambia in causing variation in the y-intercept or slope of the mean species vessel-diameter– and vessel-density–shoot-length associations at the shoot tip and base. We detected numerous cases of ecologically significant variation. For example, latewood vessels of ring porous species scale with a lower slope than earlywood, i.e., latewood vessels are relatively narrow in taller plants. This pattern is likely the result of selection favoring freezing-induced embolism resistance via narrow vessels. Wood density was negatively associated with vessel diameter, with low wood density plants having wider vessels for a given height. Species with scalariform perforation plates scale with a lower shoot base vessel-diameter–shoot-length slope, likely reflecting selection against scalariform plates in wide vessels. In other cases, functional groups scaled similarly. For example, species with successive cambia did not differ from those with conventional single cambia in their mean vessel-diameter–shoot-length scaling, rejecting our prediction that species with successive cambia should have narrower vessels for a given shoot length. They did, however, have fewer vessels per unit shoot cross-sectional area than plants of similar heights, likely because vessels have longer functional lifespans (and therefore are fewer) in species with successive cambia. Our methods illustrate how vessel diameter can be studied taking shoot length into account to detect ecologically important variation and construct theory regarding plant adaptation via the hydraulic system that includes plant size as a vital element.
Tree growth limitation at treeline has mainly been studied in terms of carbon limitation while effects and mechanisms of potential nitrogen (N) limitation are barely known, especially in the southern ...hemisphere. We investigated how soil abiotic properties and microbial community structure and composition change from lower to upper sites within three vegetation belts (Nothofagus betuloides and N. pumilio forests, and alpine vegetation) across an elevation gradient (from 0 to 650 m a.s.l.) in Cordillera Darwin, southern Patagonia. Increasing elevation was associated with a decrease in soil N‐NH₄ ⁺ availability within the N. pumilio and the alpine vegetation belt. Within the alpine vegetation belt, a concurrent increase in the soil C:N ratio was associated with a shift from bacterial‐dominated in lower alpine sites to fungal‐dominated microbial communities in upper alpine sites. Lower forested belts (N. betuloides, N. pumilio) exhibited more complex patterns both in terms of soil properties and microbial communities. Overall, our results concur with recent findings from high‐latitude and altitude ecosystems showing decreased nutrient availability with elevation, leading to fungal‐dominated microbial communities. We suggest that growth limitation at treeline may result, in addition to proximal climatic parameters, from a competition between trees and soil microbial communities for limited soil inorganic N. At higher elevation, soil microbial communities could have comparably greater capacities to uptake soil N than trees, and the shift towards a fungal‐dominated community would favour N immobilization over N mineralization. Though evidences of altered nutrient dynamics in tree and alpine plant tissue with increasing altitude remain needed, we contend that the measured residual low amount of inorganic N available for trees in the soil could participate to the establishment limitation. Finally, our results suggest that responses of soil microbial communities to elevation could be influenced by functional properties of forest communities for instance through variations in litter quality.
The beehive as a quantitative monitor of pesticide residues applied over a soybean crop was studied through a semi field experiment of controlled exposure of honey bees to pesticides in macro ...tunnels. The distribution within exposed beehives of pesticides commonly used in soybean plantation, was assessed. Residue levels of insecticides in soybean leaves, honey bees, wax, honey and pollen were analyzed. The transference from pesticides present in the environment into the beehive was evidenced. The obtained results allow relating pesticide concentrations present in the environment with traces found in foraging bees. Therefore, pesticide transference ratios could be calculated for each detected compound (acetamiprid, imidacloprid and thiamethoxam) which showed a linear inverse trend with their 1-octanol/water partition coefficient (Kow). The least transferred pesticide to the hive (acetamiprid) has the highest vapor pressure (Vp). This study gives new insights on the usefulness of monitoring the environment through beehives aiming to evaluate if agroecosystems remain sustainable. It also contributes to generate valuable information for model building aiming to predict environmental quality through beehive's analysis.
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•New insights to support beehives as environmental monitors for pesticide residues.•It is shown that bees carry pesticides applied in the field to the hive.•Pesticide transference was calculated for acetamiprid, imidacloprid, thiamethoxam.•Transferences had a linear inverse trend with their Kow.•Relationship with Vp was also observed.
We evaluated the IgG antibody titer against SARS-CoV-2 in 196 residents of a Spanish nursing home after the second dose of the BNT162b2 vaccine and the evolution of this titer over time. The role of ...the third dose of the vaccine on immune-response is also analysed in 115 of participants.
Vaccine response was evaluated 1, 3 and 6 months after second dose of Pfizer-BioNTech COVID-19 Vaccine and 30 days after booster vaccination. Total anti-RBD (receptor binding domain) IgG immunoglobulins were measured to assess response. Six month after the second dose of vaccine and previously to the booster, T-cell response was also measured in 24 resident with different antibody levels. T-spot Discovery SARS-CoV-2 kit was used to identify cellular immunogenicity.
As high as 99% of residents demonstrated a positive serological response after second dose. Only two patients showed no serologic response, two men without records of previous SARS-CoV-2 infection. A higher immune response was associated with prior SARS-CoV-2 infection regardless of the gender or age. The anti-S IgG titers decreased significantly in almost all the participants (98.5%) after six months of vaccination whatever previous COVID-infection. The third dose of vaccine increased antibody titers in all patients, although initial vaccination values were not restored in the majority of cases.
The main conclusion of the study is that vaccine resulted in good immunogenicity in this vulnerable population. Nevertheless more data are needed on the long-term maintenance of antibody response after booster vaccination.
One of the most important fields of study in material science is surface characterization. This topic is currently a field of growing interest as many functional properties depend on the surface ...texture. In this paper the authors, after a short a review of different methods for surface topography characterization and the determination of the traceability problems that arise in this type of measurements, propose four different designs of material standards that can be used to calibrate the most common optical measuring instruments used for these tasks, such as measuring microscopes, metallurgical microscopes, confocal microscopes, focus variation microscopes, etc. The authors consider that the use of this type of standards (or others similar to them) could provide a step forward in assuring metrological traceability for different metrological characteristics that enables a more precise measurement of surface features with optical measuring instruments. In addition, authors expect that this work could lay the groundwork for the development of custom standards with specialized features tuned to gain a better metrological control when measuring specific geometrical surface properties.
Male meiotic germ cell including the spermatozoa represent a great challenge to the immune system, as they appear long after the establishment of normal immune tolerance mechanisms. The capacity of ...the testes to tolerate autoantigenic germ cells as well as survival of allogeneic organ engrafted in the testicular interstitium have led to consider the testis an immunologically privileged site. Disruption of this immune privilege following trauma, tumor, or autoimmune orchitis often results in male infertility. Strong evidence indicates that indoleamine 2,3-dioxygenase (IDO) has been implicated in fetal and allograft tolerance, tumor immune resistance, and regulation of autoimmune diseases. IDO and tryptophan 2,3-dioxygenase (TDO) catalyze the same rate-limiting step of tryptophan metabolism along a common pathway, which leads to tryptophan starvation and generation of catabolites collectively known as kynurenines. However, the relevance of tryptophan metabolism in testis pathophysiology has not yet been explored. Here we assessed the in vivo role of IDO/TDO in experimental autoimmune orchitis (EAO), a model of autoimmune testicular inflammation and immunologically impaired spermatogenesis. EAO was induced in adult Wistar rats with testicular homogenate and adjuvants. Control (C) rats injected with saline and adjuvants and normal untreated rats (N) were also studied. mRNA expression of IDO decreased in whole testes and in isolated Sertoli cells during EAO. TDO and IDO localization and level of expression in the testis were analyzed by immunostaining and Western blot. TDO is expressed in granulomas from EAO rats, and similar protein levels were observed in N, C, and EAO groups. IDO was detected in mononuclear and endothelial cells and reduced IDO expression was detected in EAO group compared to N and C rats. This phenomenon was concomitant with a significant reduction of IDO activity in EAO testis measured by tryptophan and kynurenine concentrations (HPLC). Finally, in vivo inhibition of IDO with 1-methyl-tryptophan increased severity of the disease, demonstrating down regulation of IDO-based tolerance when testicular immune regulation was disrupted. We present evidence that an IDO-based mechanism is involved in testicular immune privilege.
ABSTRACTScientific advances and technological requirements to develop carbon fibre-reinforced polymers (CFRP) with excellent strength-to-weight ratios led to the high consumption of CFRP composites. ...The mechanical recycling of CFRP is a simpler, more economical, and environmentally responsible solution for effectively recovering this structural material that contains epoxy resin and carbon fibre. CFRP laminates were placed on a Computer Numerical Control (CNC) and milling cutting at 1100, 1800, and 2500 rpm. The recovered CFRP particles were mixed with acrylonitrile butadiene styrene (ABS) using the melt intercalation approach. Recovered CFRP particles increased the molecular mobility and reduced the thermal stability of ABS. The main differences between the ABS and the composites were a more pronounced necking region in the ABS than in the composites and a notable reduction in strain. The strain of the ABS was 27.58%, while in the composites, it was 4.29, 4.02, and 3.51%, depending on the cutting speed. Thus, ductility decreased up to 87% in the composites. This work’s successful CFRP mechanical recycling method provides epoxy powder, individual carbon fibres, and CFRP particles, opening a research field of great economic and environmental relevance in developing new materials.
Chagas cardiomyopathy, caused by Trypanosoma cruzi infection, continues to be a neglected illness, and has a major impact on global health. The parasite undergoes several stages of morphological and ...biochemical changes during its life cycle, and utilizes an elaborated antioxidant network to overcome the oxidants barrier and establish infection in vector and mammalian hosts. Trypanothione synthetase (TryS) catalyzes the biosynthesis of glutathione-spermidine adduct trypanothione (T(SH)2) that is the principal intracellular thiol-redox metabolite in trypanosomatids.
We utilized genetic overexpression (TryShi) and pharmacological inhibition approaches to examine the role of TryS in T. cruzi proliferation, tolerance to oxidative stress and resistance to anti-protozoal drugs. Our data showed the expression and activity of TryS was increased in all morphological stages of TryShi (vs. control) parasites. In comparison to controls, the TryShi epimastigotes (insect stage) recorded shorter doubling time, and both epimastigotes and infective trypomastigotes of TryShi exhibited 36–71% higher resistance to H2O2 (50–1000 μM) and heavy metal (1–500 μM) toxicity. Treatment with TryS inhibitors (5–30 μM) abolished the proliferation and survival advantages against H2O2 pressure in a dose-dependent manner in both TryShi and control parasites. Further, epimastigote and trypomastigote forms of TryShi (vs. control) T. cruzi tolerated higher doses of benznidazole and nifurtimox, the drugs currently administered for acute Chagas disease treatment.
TryS is essential for proliferation and survival of T. cruzi under normal and oxidant stress conditions, and provides an advantage to the parasite to develop resistance against currently used anti-trypanosomal drugs. TryS indispensability has been chemically validated with inhibitors that may be useful for drug combination therapy against Chagas disease.
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•Trypanothione synthetase (TryS) is an essential enzyme for T. cruzi.•TryS-overexpression confers higher replication rate to T. cruzi epimastigotes.•TryS provides protection against oxidative stress to different parasite stages.•TryS confers resistance to current treatment drugs, benznidazole and nifurtimox.
Previous studies showed that a naturally attenuated strain from Trypanosoma cruzi triggers an immune response mainly related to a Th2-type profile. Albeit this, a strong protection against virulent ...challenge was obtained after priming mice with this attenuated strain. However, this protection is not enough to completely clear parasites from the host. In T. cruzi infection, early Interferon-gamma (IFN-γ) is critical to lead type 1 responses able to control intracellular parasites. Therefore we evaluated whether the co-administration of a plasmid encoding murine IFN-γ could modify the immune response induced by infection with attenuated parasites and improve protection against further infections.
C57BL/6J mice were infected intraperitoneally with three doses of live attenuated parasites in combination with plasmid pVXVR-mIFN-γ. Before each infection dose, sera samples were collected for parasite specific antibodies determination and cytokine quantification. To evaluate the recall response to T. cruzi, mice were challenged with virulent parasites 30 days after the last dose and parasite load in peripheral blood and heart was evaluated.
As determined by ELISA, significantly increase in T. cruzi specific antibodies response was detected in the group in which pVXVR-mIFN-γ was incorporated, with a higher predominance of IgG2a subtype in comparison to the group of mice only inoculated with attenuated parasites. At our limit of detection, serum levels of IFN-γ were not detected, however a slight decrease in IL-10 concentrations was observed in groups in which pVXVR-mIFN-γ was supplemented. To analyze if the administration of pVXVR-mIFN-γ has any beneficial effect in protection against subsequent infections, all experimental groups were submitted to a lethal challenge with virulent bloodstream trypomastigotes. Similar levels of challenge parasites were detected in peripheral blood and heart of mice primed with attenuated parasites alone or combined with plasmid DNA. Expansion of IgG antibodies was not significant in TCC+ pVXVR-mIFN-γ; however, the overall tendency to sustain a Th2 profile was maintained.
Overall, these results suggest that administration of plasmid pVXVR-mIFN-γ could have beneficial effects on host specific antibody production in response to T. cruzi attenuated infection; however, this outcome is not reflected in an improved protection against further virulent infections.
Chagas disease, caused by the protozoan Trypanosoma cruzi, remains a major public health challenge affecting millions in Latin America and worldwide. Although significant progress has been made in ...vector control, no vaccine exists to prevent infection or mitigate disease pathogenesis. We developed a rationally designed chimeric protein vaccine, N-Tc52/TSkb20, incorporating immunodominant epitopes from two T. cruzi antigens, the amino-terminal portion of Tc52 and the TSkb20 epitope derived from trans-sialidase. The objectives of this study were to construct and characterize the antigen and evaluate its protective potential in an immunoprophylactic murine model of T. cruzi infection. The N-Tc52/TSkb20 protein was recombinantly expressed in E. coli and its identity was confirmed using mass spectrometry and Western blotting. Immunization with the chimeric protein significantly controlled parasitemia and reduced the heart, colon, and skeletal muscle parasite burdens compared to non-vaccinated mice. Protection was superior to vaccination with the individual parental antigen components. Mechanistically, the vaccine induced potent CD8+ T-cell and IFNγ responses against the incorporated epitopes and a protective IgG antibody profile. A relatively low IL-10 response favored early parasite control. These results validate the promising multi-epitope approach and support the continued development of this type of rational vaccine design strategy against Chagas disease.
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