Nitrogen is an essential element for sugarcane growth and development and is generally applied in the form of urea often much more than at recommended rates, causing serious soil degradation, ...particularly soil acidification, as well as groundwater and air pollution. In spite of the importance of nitrogen for plant growth, fewer reports are available to understand the application and biological role of N
fixing bacteria to improve N
nutrition in the sugarcane plant.
In this study, a total of 350 different bacterial strains were isolated from rhizospheric soil samples of the sugarcane plants. Out of these, 22 isolates were selected based on plant growth promotion traits, biocontrol, and nitrogenase activity. The presence and activity of the nifH gene and the ability of nitrogen-fixation proved that all 22 selected strains have the ability to fix nitrogen. These strains were used to perform 16S rRNA and rpoB genes for their identification. The resulted amplicons were sequenced and phylogenetic analysis was constructed. Among the screened strains for nitrogen fixation, CY5 (Bacillus megaterium) and CA1 (Bacillus mycoides) were the most prominent. These two strains were examined for functional diversity using Biolog phenotyping, which confirmed the consumption of diverse carbon and nitrogen sources and tolerance to low pH and osmotic stress. The inoculated bacterial strains colonized the sugarcane rhizosphere successfully and were mostly located in root and leaf. The expression of the nifH gene in both sugarcane varieties (GT11 and GXB9) inoculated with CY5 and CA1 was confirmed. The gene expression studies showed enhanced expression of genes of various enzymes such as catalase, phenylalanine-ammonia-lyase, superoxide dismutase, chitinase and glucanase in bacterial-inoculated sugarcane plants.
The results showed that a substantial number of Bacillus isolates have N-fixation and biocontrol property against two sugarcane pathogens Sporisorium scitamineum and Ceratocystis paradoxa. The increased activity of genes controlling free radical metabolism may at least in part accounts for the increased tolerance to pathogens. Nitrogen-fixation was confirmed in sugarcane inoculated with B. megaterium and B. mycoides strains using N-balance and
N
isotope dilution in different plant parts of sugarcane. This is the first report of Bacillus mycoides as a nitrogen-fixing rhizobacterium in sugarcane.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Mesocrystals are 3D ordered nanoparticle superstructures, often with internal porosity, which receive much recent research interest. While more and more mesocrystal systems are found in ...biomineralization or synthesized, their potential as material still needs to be explored. It needs to be revealed, which new chemical and physical properties arise from the mesocrystal structure, or how they change by the ordered aggregation of nanoparticles to fully exploit the promising potential of mesocrystals. Also, the mechanisms for mesocrystal synthesis need to be explored to adapt it to a wide class of materials. The last three years have seen remarkable progress, which is summarized here. Also potential future directions of this reaserch field are discussed. This shows the importance of mesocrystals not only for the field of materials research and allows the appliction of mesocrystals in advanced materials synthesis or property improvement of existing materials. It also outlines attractive research directions in this field.
This Progress Report highlights recent advances in the field of mesocrystals. Focus is on understanding of the formation mechanisms as well as the generation or change of chemical and physical properties, such as optical, magnetic, mechanical, and catalytic performance due to the mesoscopically ordered nanoparticle aggregation. Future research directions in the field are also proposed.
Activation of the phagocytosis of macrophages to tumor cells is an attractive strategy for cancer immunotherapy, but the effectiveness is limited by the fact that many tumor cells express an ...increased level of anti‐phagocytic signals (e.g., CD47 molecules) on their surface. To promote phagocytosis of macrophages, a pro‐phagocytic nanoparticle (SNPACALR&aCD47) that concurrently carries CD47 antibody (aCD47) and a pro‐phagocytic molecule calreticulin (CALR) is constructed to simultaneously modulate the phagocytic signals of macrophages. SNPACALR&aCD47 can achieve targeted delivery to tumor cells by specifically binding to the cell‐surface CD47 and block the CD47‐SIRPα pathway to inhibit the “don't eat me” signal. Tumor cell‐targeted delivery increases the exposure of recombinant CALR on the cell surface and stimulates an “eat me” signal. Simultaneous modulation of the two signals enhances the phagocytosis of 4T1 tumor cells by macrophages, which leads to significantly improved anti‐tumor efficacy in vivo. The findings demonstrate that the concurrent blockade of anti‐phagocytic signals and activation of pro‐phagocytic signals can be effective in macrophage‐mediated cancer immunotherapy.
The phagocytosis of tumor cells by macrophages requires both the coordinated disruption of “don't eat me” signals and simultaneous activation of “eat me” signals. Herein, a nanoparticle‐enabled strategy is proposed to concurrently modulate the cell surface levels of calreticulin (CALR) and CD47 to improve macrophage phagocytosis for improved cancer immunotherapy.
Sugarcane (
L.) is one of the world's highly significant commercial crops. The amounts of synthetic nitrogen (N
) fertilizer required to grow the sugarcane plant at its initial growth stages are ...higher, which increases the production costs and adverse environmental consequences globally. To combat this issue, sustainable environmental and economic concerns among researchers are necessary. The endophytic diazotrophs can offer significant amounts of nitrogen to crops through the biological nitrogen fixation mediated
gene. The
gene is the most extensively utilized molecular marker in nature for studying N
fixing microbiomes. The present research intended to determine the existence of novel endophytic diazotrophs through culturable and unculturable bacterial communities (EDBCs). The EDBCs of different tissues (root, stem, and leaf) of five sugarcane cultivars (
L. cv. Badila,
Jesw.cv Pansahi,
,
, and
Roxb.cv Uba) were isolated and molecularly characterized to evaluate N
fixation ability. The diversity of EDBCs was observed based on
gene Illumina MiSeq sequencing and a culturable approach. In this study, 319766 operational taxonomic units (OTUs) were identified from 15 samples. The minimum number of OTUs was recorded in leaf tissues of
and maximum reads in root tissues of
These data were assessed to ascertain the structure, diversity, abundance, and relationship between the microbial community. A total of 40 bacterial families with 58 genera were detected in different sugarcane species. Bacterial communities exhibited substantially different alpha and beta diversity. In total, 16 out of 20 genera showed potent N
-fixation in sugarcane and other crops. According to principal component analysis (PCA) and hierarchical clustering (Bray-Curtis dis) evaluation of OTUs, bacterial microbiomes associated with root tissues differed significantly from stem and leaf tissues of sugarcane. Significant differences often were observed in EDBCs among the sugarcane tissues. We tracked and validated the plethora of individual phylum strains and assessed their nitrogenase activity with a culture-dependent technique. The current work illustrated the significant and novel results of many uncharted endophytic microbial communities in different tissues of sugarcane species, which provides an experimental system to evaluate the biological nitrogen fixation (BNF) mechanism in sugarcane. The novel endophytic microbial communities with N
-fixation ability play a remarkable and promising role in sustainable agriculture production.
There is increasing evidence that the existence of systemic inflammation response is correlated with poor prognosis in several solid tumors. The aim of this retrospective study was to investigate the ...association between systemic immune-inflammation index (SII) and therapy response and overall survival in patients with stage III non-small cell lung cancer (NSCLC). The prognostic values of neutrophil to lymphocyte ratio (NLR), platelet to lymphocyte ratio (PLR), and prognostic nutritional index (PNI) were also evaluated.
In total, 332 patients with new diagnosis of stage III NSCLC were included in this retrospective analysis. SII was defined as platelet counts × neutrophil counts/lymphocyte counts. Receiver operating characteristic (ROC) curve was used to evaluate the optimal cut-off value for SII, NLR, PLR and PNI. Univariate and multivariate survival analysis were performed to identify the factors correlated with overall survival.
Applying cut-offs of ≥ 660 (SII), ≥ 3.57 (NLR), ≥ 147 (PLR), ≤ 52.95 (PNI), SII ≥ 660 was significantly correlated with worse ECOG PS (< 0.001), higher T stage (< 0.001), advanced clinical stage (p = 0.019), and lower response rate (p = 0.018). In univariate analysis, SII ≥ 660, NLR ≥ 3.57, PLR ≥ 147, and PNI ≤ 52.95 were significantly associated with worse overall survival (p
< 0.001). Patients with SII ≥ 660 had a median overall survival of 10 months, and patients with SII < 660 showed a median overall survival of 30 months. In multivariate analysis only ECOG PS (HR, 1.744; 95% CI 1.158-2.626; p = 0.008), T stage (HR, 1.332; 95% CI 1.032-1.718; p = 0.028), N stage (HR, 1.848; 95% CI 1.113-3.068; p = 0.018), SII (HR, 2.105; 95% CI 1.481-2.741; p < 0.001) and NLR ≥ 3.57 (HR, 1.934; 95% CI 1.448-2.585; p < 0.001) were independently correlated with overall survival.
This study demonstrates that the SII is an independent prognostic indicator of poor outcomes for patients with stage III NSCLC and is superior to other inflammation-based factors in terms of prognostic ability.
Pancreatic ductal adenocarcinoma (PDAC) is one of the most malignant tumors with a low survival rate. The therapeutic effect of chemotherapy and immunotherapy for PDAC is disappointing due to the ...presence of dense tumor stroma and immunosuppressive cells in the tumor microenvironment (TME). Herein, a tumor‐penetrating nanoparticle is reported to modulate the deep microenvironment of PDAC for improved chemoimmunotherapy. The tumor pH‐sensitive polymer is synthesized by conjugating N,N‐dipentylethyl moieties and monomethoxylpoly(ethylene glycol) onto PAMAM dendrimer, into whose cavity a hydrophobic gemcitabine (Gem) prodrug is accommodated. They self‐assemble into nanoparticles (denoted as SPN@Pro‐Gem) with the size around 120 nm at neutral pH, but switch into small particles (≈8 nm) at tumor site to facilitate deep delivery of Gem into the tumor parenchyma. In addition to killing cancer cells that resided deeply in the tumor tissue, SPN@Pro‐Gem could modulate the TME by reducing the abundance of tumor‐associated macrophages and myeloid‐derived suppressor cells as well as upregulating the expression level of PD‐L1 of tumor cells. This collectively facilitates the infiltration of cytotoxic T cells into the tumors and renders checkpoint inhibitors more effective in previously unresponsive PDAC models. This study reveals a promising strategy for improving the chemoimmunotherapy of pancreatic cancer.
A tumor penetrating nanomedicine SPN@Pro‐Gem is designed for deep tumor delivery of gemcitabine prodrug (Pro‐Gem) through tumor pH‐sensitive size switching. The SPN@Pro‐Gem not only potentiates chemotherapy of Gem, but also reduces the infiltration of immunosuppressive cells and upregulates PD‐L1 expression on tumor cells. Combining SPN@Pro‐Gem with anti‐PD‐1 antibody improves the chemoimmunotherapy of pancreatic cancer.
Lasing from an Organic Micro‐Helix Sun, Chun‐Lin; Li, Jun; Song, Qi‐Wei ...
Angewandte Chemie International Edition,
June 26, 2020, Letnik:
59, Številka:
27
Journal Article
Recenzirano
Organic solid‐state semiconductor lasers are attracting ever‐increasing interest for their potential application in future photonic circuits. Despite the great progress made in recent years, an ...organic laser from 3D chiral structures has not been achieved. Now, the first example of an organic nano‐laser from the micro‐helix structure of an achiral molecule is presented. Highly regular micro‐helixes with left/right‐handed helicity from a distyrylbenzene derivative (HM‐DSB) were fabricated and characterized under microscope spectrometers. These chiral micro‐helixes exhibit unique photonic properties, including helicity‐dependent circularly polarized luminescence (CPL), periodic optical waveguiding, and length‐dependent amplified spontaneous emission (ASE) behavior. The successful observation of laser behavior from the organic micro‐helix extends our understanding to morphology chirality of organic photonic materials and provides a new design strategy towards chiral photonic circuits.
An organic nano‐laser from the micro‐helix structure of an achiral molecule is presented. Highly regular micro‐helixes with left/right‐handed helicity from a distyrylbenzene derivative were fabricated and characterized under microscope spectrometers. These chiral micro‐helixes exhibited unique photonic properties, including helicity‐dependent circularly polarized luminescence, periodic optical waveguiding, and laser behavior.
The study was designed to isolate and characterize
spp. from sugarcane rhizosphere, and to evaluate their plant- growth- promoting (PGP) traits and nitrogenase activity. A biological nitrogen-fixing ...microbe has great potential to replace chemical fertilizers and be used as a targeted biofertilizer in a plant. A total of 100 isolates from sugarcane rhizosphere, belonging to different species, were isolated; from these, 30 isolates were selected on the basis of preliminary screening, for
antagonistic activities against sugarcane pathogens and for various PGP traits, as well as nitrogenase activity. The production of IAA varied from 312.07 to 13.12 μg mL
in tryptophan supplemented medium, with higher production in AN15 and lower in CN20 strain. The estimation of ACC deaminase activity, strains CY4 and BA2 produced maximum and minimum activity of 77.0 and 15.13 μmoL mg
h
. For nitrogenase activity among the studied strains, CoA6 fixed higher and AY1 fixed lower in amounts (108.30 and 6.16 μmoL C
H
h
mL
). All the strains were identified on the basis of 16S rRNA gene sequencing, and the phylogenetic diversity of the strains was analyzed. The results identified all strains as being similar to
spp. Polymerase chain reaction (PCR) amplification of
and antibiotic genes was suggestive that the amplified strains had the capability to fix nitrogen and possessed biocontrol activities. Genotypic comparisons of the strains were determined by BOX, ERIC, and REP PCR profile analysis. Out of all the screened isolates, CY4 (
) and CN11 (
) showed the most prominent PGP traits, as well as nitrogenase activity. Therefore, only these two strains were selected for further studies; Biolog profiling; colonization through green fluorescent protein (GFP)-tagged bacteria; and
gene expression using quantitative real-time polymerase chain reaction (qRT-PCR) analysis. The Biolog phenotypic profiling, which comprised utilization of C and N sources, and tolerance to osmolytes and pH, revealed the metabolic versatility of the selected strains. The colonization ability of the selected strains was evaluated by genetically tagging them with a constitutively expressing GFP-pPROBE-pTet
-OT plasmid. qRT-PCR results showed that both strains had the ability to express the
gene at 90 and 120 days, as compared to a control, in both sugarcane varieties GT11 and GXB9. Therefore, our isolated strains,
and
may be used as inoculums or in biofertilizer production for enhancing growth and nutrients, as well as for improving nitrogen levels, in sugarcane and other crops. The present study, to the best of our knowledge, is the first report on the diversity of
spp. associated with sugarcane in Guangxi, China.
Major depressive disorder (MDD) is a highly prevalent psychiatric disorder, and inflammation has been considered crucial components of the pathogenesis of depression. NLRP1 inflammasome-driven ...inflammatory response is believed to participate in many neurological disorders. However, it is unclear whether NLRP1 inflammasome is implicated in the development of depression.
Animal models of depression were established by four different chronic stress stimuli including chronic unpredictable mild stress (CUMS), chronic restrain stress (CRS), chronic social defeat stress (CSDS), and repeat social defeat stress (RSDS). Depressive-like behaviors were determined by sucrose preference test (SPT), forced swim test (FST), tail-suspension test (TST), open-field test (OFT), social interaction test (SIT), and light-dark test (LDT). The expression of NLRP1 inflammasome complexes, BDNF, and CXCL1/CXCR2 were tested by western blot and quantitative real-time PCR. The levels of inflammatory cytokines were tested by enzyme-linked immunosorbent assay (ELISA) kits. Nlrp1a knockdown was performed by an adeno-associated virus (AAV) vector containing Nlrp1a-shRNA-eGFP infusion.
Chronic stress stimuli activated hippocampal NLRP1 inflammasome and promoted the release of pro-inflammatory cytokines IL-1β, IL-18, IL-6, and TNF-α in mice. Hippocampal Nlrp1a knockdown prevented NLRP1 inflammasome-driven inflammatory response and ameliorated stress-induced depressive-like behaviors. Also, chronic stress stimuli caused the increase in hippocampal CXCL1/CXCR2 expression and low BDNF levels in mice. Interestingly, Nlrp1a knockdown inhibited the up-regulation of CXCL1/CXCR2 expression and restored BDNF levels in the hippocampus.
NLRP1 inflammasome-driven inflammatory response contributes to chronic stress induced depressive-like behaviors and the mechanism may be related to CXCL1/CXCR2/BDNF signaling pathway. Thus, NLRP1 inflammasome could become a potential antidepressant target.
As one of the most ubiquitous bulk reagents available, the intrinsic chemical inertness of tetrahydrofuran (THF) makes direct and site‐selective C(sp3)−H bond activation difficult, especially under ...redox neutral condition. Here, we demonstrate that semiconductor quantum dots (QDs) can activate α‐C−H bond of THF via forming QDs/THF conjugates. Under visible light irradiation, the resultant alkoxyalkyl radical directly engages in radical cross‐coupling with α‐amino radical from amino C−H bonds or radical addition with alkene or phenylacetylene, respectively. In contrast to stoichiometric oxidant or hydrogen atom transfer reagents required in previous studies, the scalable benchtop approach can execute α‐C−H bond activation of THF only by a QD photocatalyst under redox‐neutral condition, thus providing a broad of value added chemicals starting from bulk THFs reagent.
As one of the most ubiquitous bulk reagents available, THF is activated by visible light irradiation of quantum dots in a direct, site‐selective and redox‐neutral manner. The resultant α‐oxyalkyl radicals, generated from α‐C−H of THF on the surface of QD, enable either coupling with the α‐amino radical of amines, or addition to chromones and terminal alkynes.
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