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"Cun, Zhu"
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Photosynthetic performance and photosynthesis-related gene expression coordinated in a shade-tolerant species Panax notoginseng under nitrogen regimes
Background
Nitrogen (N) is an essential component of photosynthetic apparatus. However, the mechanism that photosynthetic capacity is suppressed by N is not completely understood. Photosynthetic capacity and photosynthesis-related genes were comparatively analyzed in a shade-tolerant species
Panax notoginseng
grown under the levels of low N (LN), moderate N (MN) and high N (HN).
Results
Photosynthetic assimilation was significantly suppressed in the LN- and HN-grown plants. Compared with the MN-grown plants, the HN-grown plants showed thicker anatomic structure and larger chloroplast accompanied with decreased ratio of mesophyll conductance (g
m
) to Rubisco content (g
m
/Rubisco) and lower Rubisco activity. Meanwhile, LN-grown plants displayed smaller chloroplast and accordingly lower internal conductance (g
i
). LN- and HN-grown individuals allocated less N to light-harvesting system (N
L
) and carboxylation system (N
C
), respectively. N surplus negatively affected the expression of genes in Car biosynthesis (
GGPS
,
DXR
,
PSY
,
IPI
and
DXS
). The LN individuals outperformed others with respect to non-photochemical quenching. The expression of genes (
FBA, PGK, RAF2, GAPC, CAB, PsbA
and
PsbH
) encoding enzymes of Calvin cycle and structural protein of light reaction were obviously repressed in the LN individuals, accompanying with a reduction in Rubisco content and activity. Correspondingly, the expression of genes encoding
RAF2
,
RPI4
,
CAB
and
PetE
were repressed in the HN-grown plants.
Conclusions
LN-induced depression of photosynthetic capacity might be caused by the deceleration on Calvin cycle and light reaction of photosynthesis, and HN-induced depression of ones might derive from an increase in the form of inactivated Rubisco.
Journal Article
Extracting more light for vertical emission: high power continuous wave operation of 1.3-μm quantum-dot photonic-crystal surface-emitting laser based on a flat band
For long distance optical interconnects, 1.3-μm surface-emitting lasers are key devices. However, the low output power of several milliwatts limits their application. In this study, by introducing a two-dimensional photonic-crystal and using InAs quantum dots as active materials, a continuous-wave, 13.3-mW output power, 1.3-μm wavelength, room-temperature surface-emitting laser is achieved. In addition, such a device can be operated at high temperatures of up to 90 °C. The enhanced output power results from the flat band structure of the photonic crystal and an extra feedback mechanism. Surface emission is realized by photonic crystal diffraction and thus the distributed Bragg reflector is eliminated. The proposed device provides a means to overcome the limitations of low-power 1.3-μm surface-emitting lasers and increase the number of applications thereof.
Journal Article
The salt secretion of leaves promotes the competitiveness of Reaumuria soongarica in a desert grassland
Background
For better understanding the mechanism of
Reaumuria soongarica
community formation in a salt stressed grassland ecosystem, we designed a field experiment to test how leaves salt secretion changes the competitive relationship between species in this plant communities.
Results
Among the three species (
R. soongarica, Stipa glareosa
and
Allium polyrhizum
) of the salt stressed grassland ecosystem, the conductivity of
R. soongarica
rhizosphere soil was the highest in five soil layers (0–55 cm depth). The high soil conductivity can increase the daily salt secretion rate of plant leaves of
R. soongarica
. In addition, we found the canopy size of
R. soongarica
was positively related to the distance from
S. glareosa
or
A. polyrhizum
. The salt-tolerance of
R. soongarica
was significantly higher than the other two herbs (
S. glareosa
and
A. polyrhizum
). Moreover, there was a threshold (600 µS/cm) for interspecific competition of plants mediated by soil conductivity. When the soil conductivity was lower than 600 µS/cm, the relative biomass of
R. soongarica
increased with the soil conductivity increase.
Conclusions
The efficient salt secretion ability of leaves increases soil conductivity under the canopy. This leads the formation of a “saline island” of
R. soongarica.
Meanwhile
R. soongarica
have stronger salt tolerance than
S. glareosa
and
A. polyrhizum.
These promote the competitiveness of
R. soongarica
and inhibit interspecies competition advantage of the other two herbs (
S. glareosa
and
A. polyrhizum
) in the plant community. It is beneficial for
R. soongarica
to establish dominant communities in saline regions of desert grassland.
Journal Article
Chemical composition and growth characteristics of Amorphophallus bulbifer
Konjac is an important horticultural vegetable and characteristic cash crop.
Amorphophallus bulbifer
has many advantages such as high yield, good quality and strong resistance. However, the awareness of collection and classification of germplasm resources is not strong, the germplasm resources are mixed in planting, there is a lack of good varieties, and the chemical composition of
A. bulbifer
is still unclear. Therefore, 5 self-selected
A. bulbifer
germplasm resources were used as experimental materials to study the growth, physicochemical properties and nutritional components by correlation analysis, principal components analysis (PCA) and metabolomic analysis. The results showed that
A. bulbifer
had strong growth adaptability, konjac glucomanan (KGM) content was 34.88% to 65.72%, viscosity was up to 19513.33 mPa.s, in addition, it was rich in starch, crude protein, amino acids and other nutrients. The aboveground growth and underground yield of konjac had significant positive correlation with each other (
p
< 0.05) and KGM had significant positive correlation with viscosity (
r
= 0.8,
p
< 0.001), but had significant negative correlation with starch, soluble sugar and crude fiber (
p
< 0.01), respectively. 945 metabolites were detected in the metabolome. Besides the primary metabolites, there were also abundant secondary metabolites such as flavonoids, alkaloids, organoheterocyclic compounds, phytohormones and other secondary metabolites. Carbohydrates and its derivatives, amino acids and its derivatives, organic acids and its derivatives, organoheterocyclic compounds and lipids were the main differential metabolites, among which D-Gluconic acid was an important differential metabolite. In conclusion, this study confirmed that
A. bulbifer
has good physical and chemical properties and rich nutritional components, suitable for the development and utilization of high value-added products.
Highlights
1. There was a significant positive correlation among petiole diameter, plant height, leaf width and yield, and the correlation coefficient was 0.59 or above.
2. Konjac glucomannan was positively correlated with viscosity and negatively correlated with starch, soluble sugar and crude fiber.
3. By principal components analysis, 5
Amorphophallus bulbifer
germplasm resources were divided into 3 categories. The first category was ‘YunRe1701’, which was significantly higher than other varieties and had the highest yield. The second category was ‘YunRe1709’ and ‘YunRe1726’ with KGM content of about 65%. The third category was ‘YunRe1707’ and ‘YunRe1710’ with better comprehensive performance.
4. D-gluconic acid was an important differential metabolite among
A. bulbifer
varieties.
Journal Article
Percutaneous Alginate Hydrogel Endomyocardial Injection with a Novel Dedicated Catheter Delivery System: An Animal Feasibility Study
The objective of this preclinical study was to evaluate the feasibility and safety of transcatheter endocardial alginate hydrogel injection (TEAi) in a large animal model, utilizing the high-stiffness XDROP® alginate hydrogel in combination with the dedicated EndoWings® catheter-based system. All swine (
n
= 9) successfully underwent TEAi without complications. Acute results from a subset of animals (
n
= 5) demonstrated the ability of the catheter to access a wide range of endomyocardial areas and achieve consecutive circumferential hydrogel distribution patterns within the mid-left ventricular wall. Histological examinations at 6 months (
n
= 4) demonstrated that the XDROP® remained localized within the cardiac tissue. In addition, serial echocardiographic imaging showed that XDROP® had no adverse impacts on LV systolic and diastolic functions. In conclusion, this innovative combination technology has the potential to overcome the translational barriers related to alginate hydrogel delivery to the myocardium.
Graphical abstract
Journal Article
High nitrogen inhibits photosynthetic performance in a shade-tolerant and N-sensitive species Panax notoginseng
Nitrogen (N) is a primary factor limiting leaf photosynthesis. However, the mechanism of high-N-driven inhibition on photosynthetic efficiency and photoprotection is still unclear in the shade-tolerant and N-sensitive species such as Panax notoginseng. Leaf chlorophyll (Chl) content, Ribulose-1,5-bisphosphate carboxylase oxygenase (Rubisco) activity and content, N allocation in the photosynthetic apparatus, photosynthetic performance and Chl fluorescence were comparatively analyzed in a shade-tolerant and N-sensitive species P. notoginseng grown under the levels of moderate nitrogen (MN) and high nitrogen (HN). The results showed that Rubisco content, Chl content and specific leaf nitrogen (SLN) were greater in the HN individuals. Rubisco activity, net photosynthetic rate (Anet), photosynthetic N use efficiency (PNUE), maximum carboxylation rate (Vcmax) and maximum electron transport rate (Jmax) were lower when plants were exposed to HN as compared with ones to MN. A large proportion of leaf N was allocated to the carboxylation component under the levels of MN. More N was only served as a form of N storage and not contributed to photosynthesis in HN individuals. Compared with the MN plants, the maximum quantum yield of photosystem II (Fv/Fm), non-photochemical quenching of PSII (NPQ), effective quantum yield and electron transport rate were obviously reduced in the HN plants. Cycle electron flow (CEF) was considerably enhanced in the MN individuals. There was not a significant difference in maximum photo-oxidation P700+ (Pm) between the HN and MN individuals. Most importantly, the HN individuals showed higher K phase in the fast chlorophyll fluorescence induction kinetic curve (OJIP kinetic curve) than the MN ones. The results obtained suggest that photosynthetic capacity might be primarily inhibited by the inactivated Rubisco in the HN individuals, and HN-induced depression of photoprotection might be caused by the photodamage to the donor side of PSII oxygen-evolving complex.
Journal Article
Identification of candidate genes and residues for improving nitrogen use efficiency in the N-sensitive medicinal plant Panax notoginseng
Background
Nitrogen (N) metabolism-related key genes and conserved amino acid sites in key enzymes play a crucial role in improving N use efficiency (NUE) under N stress. However, it is not clearly known about the molecular mechanism of N deficiency-induced improvement of NUE in the N-sensitive rhizomatous medicinal plant
Panax notoginseng
(Burk.) F. H. Chen. To explore the potential regulatory mechanism, the transcriptome and proteome were analyzed and the three-dimensional (3D) information and molecular docking models of key genes were compared in the roots of
P. notoginseng
grown under N regimes.
Results
Total N uptake and the proportion of N distribution to roots were significantly reduced, but the NUE, N use efficiency in biomass production (NUEb), the recovery of N fertilizer (RNF) and the proportion of N distribution to shoot were increased in the N
0
-treated (without N addition) plants. The expression of N uptake- and transport-related genes
NPF1.2
,
NRT2.4
,
NPF8.1
,
NPF4.6
,
AVP
, proteins AMT and NRT2 were obviously up-regulated in the N
0
-grown plants. Meanwhile, the expression of
CIPK23
,
PLC2
,
NLP6
,
TCP20
, and
BT1
related to the nitrate signal-sensing and transduction were up-regulated under the N
0
condition. Glutamine synthetase (GS) activity was decreased in the N-deficient plants, while the activity of glutamate dehydrogenase (GDH) increased. The expression of genes
GS1-1
and
GDH1
, and proteins GDH1 and GDH2 were up-regulated in the N
0
-grown plants, there was a significantly positive correlation between the expression of protein GDH1 and of gene
GDH1
. Glu192, Glu199 and Glu400 in PnGS1 and PnGDH1were the key amino acid residues that affect the NUE and lead to the differences in GDH enzyme activity. The 3D structure, docking model, and residues of
Solanum tuberosum
and
P. notoginseng
was similar.
Conclusions
N deficiency might promote the expression of key genes for N uptake (genes
NPF8.1
,
NPF4.6
,
AMT
,
AVP
and
NRT2
), transport (
NPF1.2
and
NRT2.4
), assimilation (proteins GS1 and GDH1), signaling and transduction (genes
CIPK23
,
PLC2
,
NLP6
,
TCP20
, and
BT1
) to enhance NUE in the rhizomatous species. N deficiency might induce Glu192, Glu199 and Glu400 to improve the biological activity of GS1 and GDH, this has been hypothesized to be the main reason for the enhanced ability of N assimilation in N-deficient rhizomatous species. The key genes and residues involved in improving NUE provide excellent candidates for the breeding of medicinal plants.
Journal Article
Bio‐inspired photonic crystals: Tailoring the dielectric building blocks to control the light propagation
Photonic crystals have drawn tremendous attention in recent years owing to their unique optical properties and remarkable advantages in various applications such as bioassays, sensors and optical devices. Benefiting from the spatially ordered structures, the flow of visible light can be manipulated by photonic crystals in a controlled manner. In this review, we summarize recent progress toward bio‐inspired photonic crystals, including techniques for the construction of spatially ordered structures in diverse dimensions for photonic crystals, and strategies to manipulate the periodicity of the dielectric building blocks to control the light propagation in the presence of external stimuli. We start with the description of structure induced colors in nature with a systematic investigation to reveal the derivation of these colors, followed by a discussion on the design and fabrication of various types of bio‐inspired photonic crystals by manipulating the arrangement of dielectric building blocks. We also highlight the stimuli responsive photonic crystals with tunable optical properties and their applications in sensing and color display. Taking advantage of the spatial ordered structures, bio‐inspired photonic crystals have drawn tremendous attention in bioassays, sensors, and optical devices. This review summarizes recent progress toward bio‐inspired photonic crystals, including the origination of vivid structural color in living creatures, and strategies to construct the periodic ordered structures and manipulate the photonic stop band to achieve the control of light propagation.
Journal Article
Percutaneous Endocardial Alginate–Hydrogel Injection in the Treatment of Heart Failure: First-in-Human Study
Abstract
Aims
Despite the potential of alginate hydrogel intramyocardial injections in the treatment of heart failure (HF), minimally invasive implantation techniques remain scarce. This study evaluated the safety and feasibility of percutaneous transcatheter endocardial alginate hydrogel injection (TEAi), facilitated by novel implants and a dedicated catheter-based device, in patients with HF with reduced ejection fraction (HFrEF).
Methods and Results
This first-in-human study enrolled HFrEF patients [New York Heart Association (NYHA) Class III–IV and left ventricular ejection fraction (LVEF) ≤35%]. The primary endpoint was the incidence of procedure- or device-related serious adverse events (SADEs) at 30 days. Secondary endpoints included the device success rate, HF hospitalization at 6 months, and change from baseline to 6 months post-procedure in the following parameters: LVEF as assessed by MRI; NYHA functional class; 6 min walk test distance (6MWT); the quality of life assessed by the Kansas City Cardiomyopathy Heart Failure Questionnaire (KCCQ); and serum N-terminal prohormone of B-type natriuretic peptide (NT-proBNP) level. Pre- and post-procedural biomechanical analysis was also evaluated. Ten patients successfully underwent TEAi with no SADEs at 30 days. There was one death and two HF hospitalizations at 6 months. At 6 months, LVEF improved from 17.7% ± 3.8% to 24.9% ± 11.2% (P = 0.021), end-systolic volume decreased from 297.5 ± 67.9 mL to 264.8 ± 101.4 mL (P = 0.029), and KCCQ scores increased from 49.7 ± 3.9 to 79.0 ± 8.07 (P = 0.008). No statistically significant changes were observed in end-diastolic volume, NT-proBNP and 6MWT at six months compared with the baseline. Biomechanical analysis revealed a reduction in peak left ventricular end-diastolic wall stress (6.5 ± 1.1 kPa vs. 5.9 ± 1.3 kPa, P = 0.043).
Conclusions
TEAi is feasible and safe for the treatment of HFrEF, warranting further randomized, efficacy clinical trials.
Using EndoWings™ and XDROP™, we developed a percutaneous minimally invasive technique for sequential circumferential alginate hydrogel injection into LV free mid-wall. This human study assessed its safety/feasibility in HFrEF patients, with personalised biomechanical models. Key findings: high procedural success, good safety, improved EF, ESV, KCCQ scores, symptom relief, and reduced peak ED wall stress.
Journal Article