Similarly, HDPs act via a non-receptor-mediated pathway against the target cell membranes as do melittin (a non-selective cytotoxic α-helical peptide), cecropin (a non-hemolytic α-helical peptide), and androctonin (a non-hemolytic β-sheeted peptide) [84] and [85]. Therefore, the biological activity shown 5-FU clinical trial by these peptides suggests the existence of killing mechanisms that involve

perturbation of the plasma membrane, inducing necrosis. Membrane-active peptides can induce the permeabilization of mitochondria, triggering apoptosis [82]. A cationic membrane-active antimicrobial peptide, CNGRC-GG-D(KLAKLAK)2, shows antitumor activity via the mitochondrial pathway of apoptosis [86]. Similarly, tachyplesin, a heptadecameric cationic antimicrobial peptide, could interact with the mitochondrial membranes of cancer cells and induce apoptosis [87] and [88].

www.selleckchem.com/products/gsk1120212-jtp-74057.html Thus, the cationic antimicrobial peptides exhibit antitumor activity. In the cathelicidin family, the bovine produced BMAP-27 and BMAP-28 have been shown to induce membrane permeabilization and apoptosis in human leukemic tumor cells and normal proliferating but not resting lymphocytes [89] and [90]. This is associated with cathelicidin peptide-induced membrane permeabilization and is followed by programmed cell death. This indicates that BMAP-28 induced mitochondrial membrane permeability and then caused mitochondrial depolarization and released cytochrome c, leading to apoptosis [90]. We have previously synthesized a 27-amino acid sequence from the C-terminal domain of hCAP18/LL-37 and described its antimicrobial activity against Porphyromonas and Prevotella species [62]. This peptide is designated hCAP18109–135 and consists of the active domain, as LL-37. In our recent study, hCAP18109–135 induced apoptotic cell death of squamous cell carcinoma cells, but not gingival fibroblasts or Carnitine palmitoyltransferase II normal keratinocytes and HaCaT cells [91]. The hCAP18109–135 induced apoptotic cell death was attributed to a caspase-independent

pathway ( Fig. 5, data unpublished). Furthermore, we demonstrated a correlation between different apoptotic events affecting the mitochondria, cytosol, and nuclei following hCAP18109–135 inductions. In order to examine the apoptotic effect of hCAP18109–135 on human squamous cell carcinoma SAS-H1 cells, the peptide was added at a concentration of 40 μg/ml in the presence of 10% fetal bovine serum. We showed that hCAP18109–135 elicited the translocation of Bax to the mitochondria and endonuclease G to the cytosol. Thus, in peptide-induced cell death, Bax-dependent endonuclease G release plays a role in caspase-independent oligonucleosomal DNA fragmentation ( Figure 6 and Figure 7, data unpublished).

The total polyphenol contents (TPC) of the extracts were determined following a Folin–Ciocalteu procedure (Singleton, Joseph, & Rossi, 1965). The appropriate dilutions of extracts were oxidised with Folin–Ciocalteu reagent and its reaction was neutralised with sodium carbonate. The absorbance

of the resulting blue colour was measured at 765 nm, after 60 min, with a UV–Vis spectrophotometer (Model U-1800; Hitachi, Tokyo, Japan). The TPC was expressed as gallic acid equivalents (GAE) in mg per mL of extract (mg GAE/mL). The determination of chlorogenic acid was performed using an HPLC this website system (Shimadzu LC-10, Kyoto, Japan) equipped with a reverse-phase column (Shim-pack C18, 4.6 mm Ø × 250 mm), thermostated at 40 °C, and a UV–Vis detector (Shimadzu SPD 10A, λ = 280 nm). An isocratic mobile phase of water:acetic acid:n-butanol (350:1:10 v/v/v) was used at a flow rate of 0.8 mL/min. The

injection volume was 10 μL. For the quantitative analysis, a standard calibration curve was obtained by plotting the peak area against different concentrations of chlorogenic acid. The curve showed see more a good linearity and followed Beer’s Law (r2 = 0.99). Similarly, the final concentration of chlorogenic acid present in the samples was determined as average content after three consecutive injections. A volume of 15 mL of each extract was treated with 60 mL of dichloromethane for 1 h and the organic phase was concentrated to 2 mL under reduced pressure. The HPLC analysis was performed on a Shimadzu LC-10A system equipped with a UV–Vis detector SPD 10A set at 272 nm. The Thalidomide experiments were carried out on a reversed-phase Shim-pack C18 (4.6 mm Ø × 250 mm) column. The system was operated isocratically at 30 °C using a mobile phase composed of acetonitrile:0.1% formic

acid (15:85 v/v), with a flow rate of 1.0 mL/min. Prior to injection, all the samples were centrifuged at 2800g for10 min (Hermle, Z 200A, Wehingen, Germany) and filtered through 0.22-μm micropore membranes. The injection volume was 10 μL for the mate extract and 5 μL for the concentrated mate extract. For quantitative analysis, standard calibration curves were obtained for caffeine (1.0–100.0 μg/mL; r2 = 0.99) and for theobromine (2.5–50 μg/mL; r2 = 0.99). The final concentrations of each sample were determined by three consecutive injections ( Strassmann et al., 2008). The extraction procedure was performed according to Gnoatto, Shenkel, and Bassani (2005). The saponins present in 10 mL of each of the two extracts were hydrolysed with 5 mL of HCl (12 M) for 2 h under reflux. The saponins were extracted with 6 mL of chloroform. The organic phase was evaporated in a rotary evaporator and the residue was resuspended in 10 mL of ethanol.

Among the major microorganisms known for their ability to produce enzymes BKM120 solubility dmso that degrade the cell wall of plants, fungi comprise the most interesting group (Hegde, Kavitha, Varadaraj, & Muralikrishna, 2006). The genus Rhizopus is one of the most promising in this process because it has been shown that, besides the ability to increase the protein content of the raw materials of low nutritional value, these proteins possess functional activity and specific catalytic activity. Furthermore, the fungi of this genus are well indicated for not producing toxic substances ( Oliveira et al., 2010). The aim of this study was to determine the profile of

phenolic acids derived from solid state fermentation of rice bran with the fungus Rhizopus oryzae and evaluate the antioxidant capacity and inhibition of enzymes peroxidase and polyphenol oxidase by extracts containing these compounds. The fungus R. oryzae (CCT 1217), was obtained from the André Tosello Foundation (FAT), Campinas, Brazil. The cultures were maintained at 4 °C in slants of potato dextrose agar (PDA, Acumedia®). The spores were spread by adding 5 mL of an aqueous emulsion (Tween 80 at 0.2%v/v) and they were incubated for 7 days at 30 °C until a whole new sporulation of the fungus by adding 0.2 mL of the emulsion in Petri dishes containing potato dextrose agar. Spore suspension for fermentation was achieved by adding 10 mL of an aqueous emulsion of Tween 80 (0.2%)

to each plate. The release of spores was obtained by scraping find more the Bacterial neuraminidase plates with a Drigalski handle and the concentrated spores solution was estimated by enumeration in a Neubauer chamber (L. Opitik, Germany). The rice bran (rice variety BR-IRGA 417) used as substrate

in fermentation was provided by industries from Rio Grande do Sul, with their particles size standardised to particles smaller than 32 mesh, and packed in 100 g in tray bioreactors (12 × 8 × 4 cm3) arranged in 2 cm layers, covered with sterilized gauze and cotton to allow aeration and prevent external contamination. The reactors containing the substrate were added in a nutrient solution (2 g/L KH2PO4, 1 g/L MgSO4 and 8 g/L (NH4)2SO4 in 0.4 N HCl) sterilized by filtration in Millipore membrane of 0.45 μm (Oliveira et al., 2010). The spores solution of the fungus R. oryzae was added at an initial concentration of 4 × 106 spores/gbran. Distilled water was added to the medium in order to adjust the humidity to 50%. The bioreactors were placed in a fermentation chamber at 30 °C with controlled humidity. Upon expiry of the incubation time (0–120 h, with sampling every 24 h), the fermented biomass was stored at −18 °C. The biomass generated during the fermentation process was indirectly estimated by the glucosamine content (Aidoo, Henry, & Wood, 1981). The glucosamine content was estimated spectrophotometrically (Biospectro, Brazil) at 530 nm using a standard curve of glucosamine (Sigma, USA) in water (1–15 mg/mL).

Although microspheres of chitosan crosslinked with 8-hydroxyquinoline-5-sulphonic acid can act as an adsorbent for several

metallic ions (Vitali et al., 2008), the interference was greatly minimised check details by the application of the pre-concentration potential. At −0.4 V, the potential chosen to pre-concentrate Cu(II), the metallic ions with a reduction potential more negative than −0.4 V are not reduced (pre-concentrated) at the electrode surface. These results show that the proposed sensor can be used for Cu(II) determination in solutions containing the tested ions without a notable loss in the analytical response. The anodic stripping voltammograms for different Cu(II) concentrations under the optimised conditions are shown in Fig. 4. In the inset, the respective calibration curve obtained is represented, while the validation parameters obtained Navitoclax cell line for Cu(II) determination employing the CPE-CTS are given in Table 1. From these data it can be seen that the current peak increases linearly with increasing Cu(II) concentration in the range of 5.0 × 10−7 to 1.4 × 10−5 mol L−1 (Δip = −0.70 + 0.12 × 107 [Cu(II)], r = 0.9990). However, for higher Cu(II) concentrations a negative deviation

from linearity was observed due to the electrode surface saturation. Also, a slight shift toward more positive potentials is observed in the peak potential with increasing Cu(II) concentration. The detection and quantification limits calculated ( Table 1) show that the proposed sensor has a high sensitivity toward Cu(II) detection. The relative Tenofovir price standard deviation (n = 8) was lower than 3.0% for the determination of Cu(II) in solutions with concentrations of 6.0 × 10−6, 5.0 × 10−5 and 1.5 × 10−4 mol L−1

indicating that the electrode provides reliable data with excellent precision. In this study, the concentration of 1.5 × 10−4 mol L−1 Cu(II) is out of the linear range of the calibration curve, however, the relative standard deviation was practically the same as those observed for the other concentrations lying within the calibration curve. This behaviour indicates that the electrode provides reliable data even for solutions with concentrations slightly higher than those of the calibration curve. The repeatability for ten measurements of the current peak for solutions of 5.0 × 10−5 mol L−1 Cu(II) under optimised conditions was excellent, with relative standard deviations of 1.31%. The reproducibility of the current peak was tested over four days using different solutions prepared in the concentration of 5.0 × 10−5 mol L−1 Cu(II). The relative standard deviation was 2.73%. When compared to other modified carbon paste electrodes employed for Cu(II) determination, the CPE-CTS sensor also showed good performance. For example, a carbon paste electrode modified with 3,4-dihydro-4,4,6-trimethyl-2(1H)-pyrimidine thione for use in potentiometry showed a linear range of 9.8 × 10−7 to 7.

The potential recyclability of CNT-containing plastic parts is not as straightforward as other plastics not containing carbon nanomaterials. All CNT-containing plastic parts are black in color. With present recycling technology, it is not possible for plastic recyclers to separate different

types of black plastics by plastic type. This inability to differentiate between black plastics creates a “down-cycling” or no recycle option where all black plastics are grouped together into one batch and shredded to create post-consumer black plastics, potentially diluting the beneficial mechanical and electromagnetic properties of the material. It would also expand, albeit diluted, Z-VAD-FMK in vitro the number of post-consumer products containing nanomaterials. Depending on the products, occupational or consumer exposure is possible. With the advances in technology, it may be possible to design a “trigger” material into the manufacture of CNT products that can be used to separate CNT-containing black plastics from non-CNT products. This would allow the segregation of these plastics

for potential “up-cycling” opportunities. The other option to fully benefit from the recycling of CNT-containing materials is the implementation of a post-consumer “take-back” program. A “take-back” program Duvelisib cost may be feasible for higher end products such as electronics, automotive, aerospace and solar receivers but would not be feasible for the toy and packaging market sectors. The lower end markets would likely end up in a landfill or be incinerated thus generating another environmental exposure

scenario to include release due to UV exposure, in stormwater and/or burn. If these releases do occur, then the environment transport of these releases would need to be studied. At the end of the life of a product it is either recycled or thrown away. Depending on the country and Elongation factor 2 kinase region, if thrown away, the waste is either incinerated or landfilled. So far only one study has been published that investigated the behavior of nanoparticles during full-scale waste incineration (Walser et al., 2012). Because this work used CeO2 which does not undergo any changes during the incineration process the results from this study cannot be used to make conclusions about CNT-composites. Release of CNTs during waste incineration was modeled by Gottschalk et al., 2009 and Gottschalk et al., 2010. These authors suggested that in Switzerland the majority of all CNTs will end up in waste incineration. Of the total flow of 0.8–2.7 t/a CNTs that was predicted to reach the waste incineration plants of Switzerland, 0.5–1.8 t/a was modeled to be eliminated, the remaining fraction was attributed to filter ash (0.1–0.4 t/a) and slag (0.16–0.55 t/a), which were either exported or landfilled. The first data about incineration of CNT-composites are available.

Thus, we divided every individual tree crown into 12 layers and assigned 24 grid points to each layer. All APAR

calculations were made for each grid point, which represents a spatial subvolume of the crown. The path length of radiation reaching each grid point was calculated from the size and shape of the tree crowns through which the radiation passed, and the distribution of LA within them. Beer’s Law was applied to each path length of either direct or diffuse radiation intercepted on a grid point. Direct and diffuse radiation were treated separately, where transmission of diffuse APAR was handled by the method developed by Norman (1979). Multiple scattering was calculated by the method of Norman and Welles (1983). Total Akt inhibitor APAR per tree crown was calculated in Maestra by summing individual APAR of the sub-volumes. Potential shading by all neighboring trees within the plot on each individual tree crown was also taken into account by Maestra. To avoid edge effects, border trees (two outermost tree rows) were included in the

simulations, but not included in our evaluation of patterns of light use and tree growth. Site specific model input consisted of (i) detailed individual tree data: xy-coordinates, crown radii, total tree height, height to crown base, dbh and LA and (ii) plot characteristics: latitude, longitude, slope and bearing. We used tree data from Olaparib cost the end of the investigation period to avoid any bias from back-dating models. In addition, each tree crown was parameterized for the following:

the leaf area density (LAD) distribution, the foliage clumping factor, the leaf angle distribution, the average leaf incidence angle and the geometric crown shape. Except for the vertical LAD distribution, these parameters where taken from Picea abies literature ( Medlyn et al., 2005 and Ibrom et al., 2006) and are listed in Appendix Table A.1. In Maestra the LAD distribution is assumed to follow a β-function in the horizontal and vertical direction. LA data from the sample trees was available from a previous study (Laubhann et al., 2010) to estimate the LAD distribution for each crown along a vertical depth IKBKE profile: equation(1) rLA=β0·rCLβ1·(1-rCL)β2rLA=β0·rCLβ1·(1-rCL)β2where the relative leaf area (rLA) is the percentage of LA per crown third to the total LA of the tree and the relative crown length (rCL; 0 at the crown base and 1 at the top of the tree) (Table A.2). Parameters for the horizontal LAD distribution were taken from Ibrom et al. (2006). Daily meteorological Maestra input data (min–max temperature and total short-wave radiation) were available for all plots from 2003 to 2007 via a climate interpolation software that was parameterized and validated for Austria (Daymet; Hasenauer et al., 2003).

, 2013) and research on temperate trees indicates that high genetic variation helps support ecosystem functions (Whitham et al., 2006). When out-crossing indigenous trees exist only at very low densities in farmland, however, as is often the case when they are remnants from ABT-888 supplier natural forest otherwise cleared for crop planting (Lengkeek et al., 2005), they are vulnerable to the absence of neighbours in the landscape to support pollination, reducing the opportunities for reproduction and potentially leading to lower seed set and inbreeding depression (Lowe et al., 2005). This is a particular

concern for trees that provide fruit for human consumption, as no cross-pollination/the absence of fruit set may mean there is no reason for farmers to retain these trees in the agricultural landscape (Dawson et al., 2009). In the worst case scenario, rare, isolated trees in farm landscapes may be the ‘living dead’ (sensu Janzen, 1986; i.e., unable to pollinate and set seed) and will only survive for the current generation. Some have argued that further promoting tree domestication has negative impacts for the diversity of agricultural landscapes at both inter- and intra-specific levels, and this is most clearly seen if it leads to clonal tree monocultures (see Section 4.3). On the other hand, without the improvements in tree yield and quality associated with domestication, farmers may choose

not to plant trees at all on their land, but to cultivate other plants that are (otherwise) more productive (Sunderland, 2011). At an intra-specific level, domestication processes always cause shifts and/or losses in underlying genetic HSP assay diversity in the manipulated populations (Dawson et al., 2009), but the extent and nature of these changes depends on the domestication method adopted, with some approaches more favourable for maintaining diversity (Cornelius et al., 2006). The participatory domestication approach (Appendix B, Aurora Kinase Section 3.2), which is based on bringing selected indigenous trees from local wild stands into farms, appears to provide a good balance between farm-level productivity gains and the landscape-level conservation of genetic

resources (Leakey, 2010). Genetic-model analysis of a participatory domestication project with peach palm in Peru, for example, showed that the risk of genetic erosion in a regional context was low (Cornelius et al., 2006). The wide use of clonal propagation methods during participatory domestication could, however, cause longer-term challenges for intra-specific diversity, especially if substantial inter-village germplasm exchange occurs (expansion of a few clones). Tree commodity crops represent something of an exception to the sparse information available on the value of other tree products (as exemplified in Sections 2 and 3), as export data are compiled widely by national governments and are further assembled by FAO’s Statistics Division (FAOSTAT, 2013).

This included null alleles, likely due www.selleckchem.com/products/s-gsk1349572.html to a deletion or primer site mutation, intermediate alleles comprising

fractional repeats, and copy-number variants such as duplications and triplications of the whole locus. All variant alleles were confirmed by retyping or sequencing at the laboratory that had performed the original STR typing. The proportion of variant alleles differed greatly among markers (Fig. 4), with DYS458 showing the highest (n = 385) and DYS391 and DYS549 showing the lowest number (n = 1). Four of the six PPY23-specific markers (DYS481, DYS570, DYS576 and DYS643) had comparatively high numbers of variant alleles. Only two single non-fractional off-ladder alleles (allele 6 at GATAH4, allele 15 at DYS481) were observed in this study. On the other hand, only five of the 19 intermediate alleles observed for the six PPY23-specific markers (18.2, 18.3, 19.3 and 20.3 at DYS570, 11.1 at DYS643) were included in the bin set of the allelic ladder (Table S3). Some 75 different intermediate alleles occurred at one of 18 Y-STR loci and were seen in 550 samples (Table S3). DYS458 was

the locus with the highest proportion of intermediate alleles (16 different in 374 samples), followed by DYS385ab (12 different in 57 samples) and DYS448 (8 different in 23 samples). Of the PPY23-specific markers, DYS481 had the Selleck ATR inhibitor highest number of different intermediate alleles (5 in 26 samples) of which 25.1 was the most frequent (n = 13). The structure of 11.1 at the DYS643 marker (observed in 11 samples in our study) has been reported previously [26] and is included already in the PPY23 allelic ladder. A total of 133 null alleles were observed at 17 loci (Table S3), which corresponds to an overall frequency of 0.03%. The DYS448 locus showed the highest number of null alleles (n = 59), followed by PPY23-specific markers DYS576 (n = 14), DYS481 (n = 11) and DYS570 (n = 11). In nine samples, a large

deletion was detected at Yp11.2 encompassing the AMELY region that removed four adjacent loci (DYS570, DYS576, DYS458 and DYS481). All these samples were of Asian ancestry, namely Indians from Singapore, Tamils from Cell press Southern India and British Asians with reported origins from Pakistan or India, where this type of deletion is frequent [27] and [28]. Furthermore, two of the nine samples also carried a null allele at DYS448 [29]. Upon retyping with autosomal kits, all these samples showed a deletion of the AMELY gene locus. Another large deletion located at Yq11 and encompassing the AZFa region [30] affected two adjacent loci (DYS389I/II and DYS439) and was detected in one African American sample. Concomitant null alleles at three loci were observed in a Han Chinese sample (DYS448, DYS458, GATAH4) and an Indian sample (DYS392, DYS448, DYS549). The DYS448 and DYS456 markers were both not amplifiable in an Iraqi sample.

Thus, HA might not only stimulate expression of the provirus, but also affect the viability and infectivity of the released virions. A similar inhibition of HIV-1 by reactive oxygen species was indeed shown in the case of bleomycin (Georgiou et al., 2004). Heme oxygenase has been suggested to exert various immunoregulatory effects on innate and adaptive immune cells, and to inhibit pathogenesis of several immune-mediated inflammatory diseases find more (Soares et al., 2009). Further, analysis of HO-1 promoter polymorphism revealed that Caucasian HIV-1-infected patients who maintain low levels of immune activation and control

HIV-1 viral loads to undetectable levels are more likely to possess a specific microsatellite (GT)n repeat and two single nucleotide polymorphisms in HO-1 promoter region CDK activation that favor enhanced HO-1 gene expression ( Seu et al., 2009). The ability of cells to become activated remained unaffected by HA as demonstrated by expression of the early activation marker CD69, characterized by flow cytometry. Since the activation of T-cells constitutes an essential component of immune responses to the virus itself as well as to other infections, we consider the finding that HA does not seem to generally decrease the activation of T-cells as important. Moreover, HA did not induce any global activation of T-cells either; this finding is significant as well, since a nonspecific

T-cell activation and release of proinflammatory cytokines should be avoided. The effect of HA thus could be compared to the effect of 5-hydroxynaphthalene-1,4-dione, a compound recently described to reactivate the latent provirus without cellular activation (Yang et al., 2009). In vivo, HIV-1 infection can coincide with several conditions that lead to acute or chronic hemolysis that could cause a similar exposure to extracellular heme as does administration of HA. These conditions include genetically determined glucose-6-phosphate dehydrogenase deficiencies, sickle cell anemia, thalasemia or other hemoglobinopathies as well as various other diseases involving hemolytic episodes or chronic hemolysis, especially malaria ( Lopez

et al., 2010 and Pamplona et al., 2009). It would be worthwhile to determine a possible heptaminol correlation of HIV-1/AIDS progression with these conditions. However, the situation is complex and therapeutic interventions, namely iron supplementation, could strongly affect the fine balance of pro-oxidative and anti-oxidative agents. In clinics, HA is used to treat acute attacks of hepatic porphyrias. The mean maximum plasma levels of heme after a single dose of HA 3 mg/kg body weight was determined as 60 μg/ml (corresponds to 2.4 μl/ml of HA), with a plasma half-life of 10.8 h and a distribution volume of 3.4 L (Tokola et al., 1986). The concentrations of HA used throughout this paper are thus very close to the levels achieved in clinics.

During loading, RIP signals from the upper and the lower abdomen demonstrated inconsistent patterns. Cross-sectional area of the upper abdomen increased during inhalation in three subjects and decreased in two. Cross-sectional area of the lower abdomen decreased during inhalation in four subjects and increased in one. Before threshold loading, mean electrical-PdiTw was 39.3 ± 2.8 cm H2O and mean magnetic-PdiTw was 46.2 ± 2.4 cm H2O (p = 0.002). After loading, electrical-PdiTw and/or magnetic-PdiTw

decreased by ≥15% from baseline in four subjects indicating development of contractile fatigue ( Kufel et al., 2002) ( Fig. 7). Duration of loading was 567 ± 65 s in the fatiguers and 661 ± 27 s in the non-fatiguers (p = 0.23). To explore potential determinants of contractile fatigue of the diaphragm alone (as Selleckchem AUY922 indicated by the decreases in electrical-PdiTw) or in combination with contractile fatigue of the rib-cage muscles

(as indicated by the decreases in magnetic-PdiTw) (Similowski et al., 1998), breathing pattern, respiratory muscle pressure output and recruitment during loading were compared in fatiguers and Carfilzomib in vivo non-fatiguers. Between the onset and end of loading, there were no differences in TTdi (Fig. 8), ΔPga/ΔPes, TI and ΔEAdi between the two groups (data not shown). In contrast, respiratory frequency was faster and duration of exhalation was shorter in fatiguers than in non-fatiguers (p ≤ 0.04; ANOVA) ( Fig. 9). At task failure, PETCO2 was 48 ± 3 mm Hg in fatiguers and 59 ± 3 mm Hg in non-fatiguers (p = 0.045). The main finding of the study is that hypercapnia during acute loading in awake subjects primarily results from reflex inhibition of central activation of the diaphragm. That all participants developed hypercapnia underscores the soundness of the experimental model used to investigate the mechanisms of alveolar hypoventilation during acute mechanical loading. Alveolar hypoventilation was accompanied by submaximal EAdi and by inconsistent development of contractile fatigue. That is, the primary mechanism of hypercapnia was submaximal diaphragmatic

recruitment caused by inadequate central activation. What caused this inadequate central activation of the diaphragm? Severe hypercapnia can blunt respiratory see more motor output (Kellog, 1964), although it is unlikely that this was the mechanism for the submaximal EAdi. The highest mean level of PETCO2 (59 ± 3 mm Hg) was well below the CO2 tension associated with respiratory motor depression (Woodbury and Karler, 1960). Moreover, the amplitude of EAdi during the IC maneuvers – recorded when the mechanical load on the respiratory muscles was briefly removed (Experiment 2) – was not depressed by PCO2. The latter observation raises the possibility that the mechanical load on the respiratory muscles was causally linked to downregulation of respiratory output to the diaphragm.