30 research outputs found
Regeneration Ecology of Chrysopogon aucheri and Cymbopogon jwarancusa in Grasslands of Upland Balochistan , Pakistan
Field experiments were conducted to investigate the seed attributes, movements and fates of dispersal units, and seedling establishment of Chrysopogon aucheri and Cymbopogon jwarancusa in a representative grassland ecosystem in upland Balochistan, Pakistan.
Cymbopogon jwarancusa had more filled and viable caryopses than Chrysopogon aucheri. Seeds (spikelets) of both species had similar morphological features. Chrysopogon aucheri had one dispersal unit, a triplet spikelet. Cymbopogon jwarancusa had four types of dispersal units: a paired spikelet, a partial raceme, an entire raceme, and a partial inflorescence comprised of two racemes.
Paired spikelets and partial racemes of Cymbopogon jwarancusa had greater mean dispersal distances (94 and 101 cm) from the edge of the basal crown of marked plants to the ground surface than triplet spikelets of Chrysopogon aucheri (79 cm). Spikelets of Cymbopogon jwarancusa and Chrysopogon aucheri moved mean distances of 26 and 32 cm, respectively, on the ground surface before becoming trapped in a microhabitat. The mean angle of dispersal for both species was toward the northeast, according to the prevailing wind direction. An ant (Tica verona) was the only detected seed (spikelet) predator for Chrysopogon aucheri. Both species had a weakly persistent soil seed bank, with higher amounts of seeds found under plant canopies compared to open interspaces.
The recruitment of Chrysopogon aucheri and Cymbopogon jwarancusa seedlings from the natural seed bank was monitored in seven different microhabitats under natural and above-normal precipitation regimes . Above-normal precipitation increased seedling recruitment for both species in all microhabitats. Cymbopogon jwarancusa had higher seedling densities than Chrysopogon auchfiri. Seedling survival and tiller development for both species were greatest in the gravel microhabitat in the natural precipitation treatment. Monsoon rains in late July enhanced emergence of both species from recently dispersed seeds but emerged seedlings did not survive to the end of the growing season.
The field studies indicate that Cymbopogon jwarancusa has a greater regeneration potential than Chrysopogon aucheri in this grassland ecosystem in upland Balochistan. It may be difficult to increase the composition of Chrysopogon aucheri, the more desirable species in these grasslands, when using management techniques that rely on natural regeneration
Water–Polysaccharide Interactions in the Primary Cell Wall of <i>Arabidopsis thaliana</i> from Polarization Transfer Solid-State NMR
Polysaccharide-rich
plant cell walls are hydrated under functional
conditions, but the molecular interactions between water and polysaccharides
in the wall have not been investigated. In this work, we employ polarization
transfer solid-state NMR techniques to study the hydration of primary-wall
polysaccharides of the model plant, <i>Arabidopsis thaliana</i>. By transferring water <sup>1</sup>H polarization to polysaccharides
through distance- and mobility-dependent <sup>1</sup>H–<sup>1</sup>H dipolar couplings and detecting it through polysaccharide <sup>13</sup>C signals, we obtain information about water proximity to
cellulose, hemicellulose, and pectins as well as water mobility. Both
intact and partially extracted cell wall samples are studied. Our
results show that water–pectin polarization transfer is much
faster than water–cellulose polarization transfer in all samples,
but the extent of extraction has a profound impact on the water–polysaccharide
spin diffusion. Removal of calcium ions and the consequent extraction
of homogalacturonan (HG) significantly slowed down spin diffusion,
while further extraction of matrix polysaccharides restored the spin
diffusion rate. These trends are observed in cell walls with similar
water content, thus they reflect inherent differences in the mobility
and spatial distribution of water. Combined with quantitative analysis
of the polysaccharide contents, our results indicate that calcium
ions and HG gelation increase the amount of bound water, which facilitates
spin diffusion, while calcium removal disrupts the gel and gives rise
to highly dynamic water, which slows down spin diffusion. The recovery
of spin diffusion rates after more extensive extraction is attributed
to increased water-exposed surface areas of the polysaccharides. Water–pectin
spin diffusion precedes water–cellulose spin diffusion, lending
support to the single-network model of plant primary walls in which
a substantial fraction of the cellulose surface is surrounded by pectins
Additional file 1 of Effect of Broncho-Vaxom (OM-85) on the frequency of chronic obstructive pulmonary disease (COPD) exacerbations
Additional file 1
Effects of Plant Cell Wall Matrix Polysaccharides on Bacterial Cellulose Structure Studied with Vibrational Sum Frequency Generation Spectroscopy and X‑ray Diffraction
The crystallinity, allomorph content,
and mesoscale ordering of
cellulose produced by Gluconacetobacter xylinus cultured with different plant cell wall matrix polysaccharides were
studied with vibrational sum frequency generation (SFG) spectroscopy
and X-ray diffraction (XRD). Crystallinity and ordering were assessed
as the intensity of SFG signals in the CH/CH<sub>2</sub> stretch vibration
region (and confirmed by XRD), while Iα content was assessed
by the relative intensity of the OH stretch vibration at 3240 cm<sup>–1</sup>. A key finding is that the presence of xyloglucan
in the culture medium greatly reduced Iα allomorph content but
with a relatively small effect on cellulose crystallinity, whereas
xylan resulted in a larger decrease in crystallinity with a relatively
small decrease in the Iα fraction. Arabinoxylan and various
pectins had much weaker effects on cellulose structure as assessed
by SFG and XRD. Homogalacturonan with calcium ion reduced the SFG
signal, evidently by changing the ordering of cellulose microfibrils.
We propose that the distinct effects of matrix polysaccharides on
cellulose crystal structure result, at least in part, from selective
interactions of the backbone and side chains of matrix polysaccharides
with cellulose chains during the formation of the microfibril
Comparison of Clinical Efficacy and Safety between Indacaterol and Tiotropium in COPD: Meta-Analysis of Randomized Controlled Trials
<div><p>Two once-daily inhaled bronchodilators, indacaterol and tiotropium, are widely used as first-line therapy in stable COPD patients. This study was performed to compare the clinical efficacy and safety between indacaterol and tiotropium in patients with moderate-to-severe COPD. MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials were searched to identify all published randomized controlled trials (RCTs). The primary outcome was trough forced expiratory volume in 1 second (FEV<sub>1</sub>) at week 12. Four RCTs were eligible for inclusion (three RCTs with moderate-to-severe COPD patients and one RCT with only severe COPD patients). Trough FEV<sub>1</sub> at weeks 12 and 26 were not significantly different between indacaterol and tiotropium by the standardized mean difference with 0.014 (95% CI, -0.036, 0.063, <i>I<sup>2</sup></i>= 23.5%) and with 0.037 (95% CI, -0.059 to 0.133, <i>I<sup>2</sup></i>= 0%) along with differences in means of 0.003L and 0.014L, respectively. Indacaterol and tiotropium also showed similar St. George`s Respiratory Questionnaire (SGRQ) total scores and percentages of patients with SGRQ improvement (≥ 4 units) at week 26. The incidences of nasopharyngitis, serious cardiovascular events, and serious adverse events were not different between indacaterol and tiotropium, while those of cough (OR = 1.68, <i>P</i> < 0.001, and RR = 1.63) and COPD worsening (OR = 1.18, <i>P</i> = 0.003, and RR = 1.12) were higher for indacaterol than tiotropium. However, when one study with only severe COPD patients was removed from the meta-analysis, the difference in the incidence of COPD worsening between indacaterol and tiotropium became non-significant (OR = 1.13, <i>P</i> = 0.204, and RR = 1.09). The clinical efficacy and serious adverse events between indacaterol and tiotropium were equivocal in patients with moderate-to-severe COPD. Cough is a common complaint associated with indacaterol, and COPD worsening needs to be carefully monitored in severe COPD patients when treated with indacaterol.</p></div
Dependence of Sum Frequency Generation (SFG) Spectral Features on the Mesoscale Arrangement of SFG-Active Crystalline Domains Interspersed in SFG-Inactive Matrix: A Case Study with Cellulose in Uniaxially Aligned Control Samples and Alkali-Treated Secondary Cell Walls of Plants
Vibrational
sum frequency generation (SFG) spectroscopy can selectively
detect not only molecules at two-dimensional (2D) interfaces but also
noncentrosymmetric domains interspersed in amorphous three-dimensional
(3D) matrixes. However, the SFG analysis of 3D systems is more complicated
than 2D systems because more variables are involved. One such variable
is the distance between SFG-active domains in SFG-inactive matrixes.
In this study, we fabricated control samples in which SFG-active cellulose
crystals were uniaxially aligned in an amorphous matrix. Assuming
uniform separation distances between cellulose crystals, the relative
intensities of alkyl (CH) and hydroxyl (OH) SFG peaks of cellulose
could be related to the intercrystallite distance. The experimentally
measured CH/OH intensity ratio as a function of the intercrystallite
distance could be explained reasonably well with a model constructed
using the theoretically calculated hyperpolarizabilities of cellulose
and the symmetry cancellation principle of dipoles antiparallel to
each other. This comparison revealed physical insights into the intercrystallite
distance dependence of the CH/OH SFG intensity ratio of cellulose,
which can be used to interpret the SFG spectral features of plant
cell walls in terms of mesoscale packing of cellulose microfibrils
Characteristics of study participants according to the radiographic activities on chest CT.
<p>Characteristics of study participants according to the radiographic activities on chest CT.</p
MTB culture yield according to radiographic activities of chest CT (A) and final diagnosis as definite or probable PTB by each radiographic grades (B).
<p>MTB = Mycobacterium tuberculosis Definite TB, defined as microbiologically, histologically or genotypically confirmed cases Probable TB, defined as clinically diagnosed case.</p
Indacaterol versus Tiotropium on SGRQ at week 26.
<p>(A) Pooled standardized difference in means for SGRQ total score at week 26 with 95% CIs of eligible studies comparing indacaterol vs tiotropium. (B) Pooled odds ratio for percentage of patients with MCID (decrease ≥ 4 units) of SGRQ total score at week 26 of eligible studies comparing indacaterol vs tiotropium. SGRQ = St. George`s Respiratory Questionnaire; MCID = minimal clinically important difference; SGRQ = St. George`s Respiratory Questionnaire.</p