A histone deacetylase, GhHDT4D, is positively involved in cotton response to drought stress.

Acetylation and deacetylation of histones are important for regulating a series of biological processes in plants. Histone deacetylases (HDACs) control the histone deacetylation that plays an important role in plant response to abiotic stress. In our study, we show the evidence that GhHDT4D (a member of the HD2 subfamily of HDACs) is involved in cotton (Gossypium hirsutum) response to drought stress. Overexpression of GhHDT4D in Arabidopsis increased plant tolerance to drought, whereas silencing GhHDT4D in cotton resulted in plant sensitivity to drought. Simultaneously, the H3K9 acetylation level was altered in the GhHDT4D silenced cotton, compared with the controls. Further study revealed that GhHDT4D suppressed the transcription of GhWRKY33, which plays a negative role in cotton defense to drought, by reducing its H3K9 acetylation level. The expressions of the stress-related genes, such as GhDREB2A, GhDREB2C, GhSOS2, GhRD20-1, GhRD20-2 and GhRD29A, were significantly decreased in the GhHDT4D silenced cotton, but increased in the GhWRKY33 silenced cotton. Given these data together, our findings suggested that GhHDT4D may enhance drought tolerance by suppressing the expression of GhWRKY33, thereby activating the downstream drought response genes in cotton.

Genome-wide identification and functional characterization of cotton (Gossypium hirsutum) MAPKKK gene family in response to drought stress.

BACKGROUND: Mitogen-activated protein kinase kinase kinases (MAPKKKs) are significant components in the MAPK signal pathway and play essential roles in regulating plants against drought stress. To explore MAPKKK gene family functioning in cotton response and resistance to drought stress, we conducted a systematic analysis of GhMAPKKKs. RESULTS: In this study, 157 nonredundant GhMAPKKKs (including 87 RAFs, 46 MEKKs and 24 ZIKs) were identified in cotton (Gossypium hirsutum). These GhMAPKKK genes are unevenly distributed on 26 chromosomes, and segmental duplication is the major way for the enlargement of MAPKKK family. Furthermore, members within the same subfamily share a similar gene structure and motif composition. A lot of cis-elements relevant to plant growth and response to stresses are distributed in promoter regions of GhMAPKKKs. Additionally, these GhMAPKKKs show differential expression patterns in cotton tissues. The transcription levels of most genes were markedly altered in cotton under heat, cold and PEG treatments, while the expressions of some GhMAPKKKs were induced in cotton under drought stress. Among these drought-induced genes, we selected GhRAF4 and GhMEKK12 for further functional characterization by virus-induced gene silencing (VIGS) method. The experimental results indicated that the gene-silenced cotton displayed decreased tolerance to drought stress. Malondialdehyde (MDA) content was higher, but proline accumulation, relative leaf water content and activities of superoxide dismutase (SOD) and peroxidase (POD) were lower in the gene-silenced cotton, compared with those in the controls, under drought stress. CONCLUSION: Collectively, a systematic survey of gene structure, chromosomal location, motif composition and evolutionary relationship of MAPKKKs were performed in upland cotton (Gossypium hirsutum). The following expression and functional study showed that some of them take important parts in cotton drought tolerance. Thus, the data presented here may provide a foundation for further investigating the roles of GhMAPKKKs in cotton response and resistance to drought stress.

[Effect of emodin on gut microbiota of rats with acute kidney failure].

The aim of this paper was to investigate the effect of emodin on gut microbiota in acute kidney injury rats( AKI). Rats were randomly divided into several groups: normal group,model group,low-dose of emodin group( 10 mg·kg~(-1)),medium-dose of emodin group( 25 mg·kg~(-1)),high-dose of emodin group( 50 mg·kg~(-1)) and control group( 5 mg·kg~(-1) of benazepril hydrochloride).The AKI model rats were established by intraperitoneal injection of small dose of gentamicin sulfate for 7 days. Two hours after intraperitoneal injection,except for the normal group and the model group,the other groups were given corresponding doses of drugs for 15 days. The serum levels of serum creatinine( SCr),urea nitrogen( BUN),plasma endotoxin level,24 h urinary protein and D-lactate in the plasma were determined by sarcosine oxidase,urease method,tal reagent method,bromo cresol chloroform method and double antibody sandwich enzyme-linked immunoadsorbent assay,respectively. Gut microbial communities were assayed by fluorescent quantitative PCR methods. HE staining was used to detect the pathological changes of the kidneys. Compared with the normal group,there were significant differences in body weight,urinary protein( UTP),bacterial endotoxin,urea nitrogen,creatinine,D-lactate in the plasma and four bacterial contents in the model group( P<0. 05). The urinary protein,urea nitrogen,D-lactate,creatinine and plasma bacterial endotoxin in control group and each emodin group were lower than those in model group,especially for high-dose of emodin( P<0. 01). Moreover,pathology resolution in high-dose emodin was better than other groups. Except for low-dose of emodin group,qRT-PCR data suggested that the amounts of Escherichia coli and Enterococcus in medication administration group were increased,while the amounts of Lactobacilli and Bifidobacterium were reduced compared with model group( P<0. 05),especially for high-dose of emodin( P<0. 01). There is a clear imbalance of gut microbiota in rats with AKI. Emodin could regulate the imbalance of gut microbiota,which might be one of the mechanisms of its effects on AKI rats.

[Effects of Carriers on ANAMMOX Sludge Activity Recovery and Microbial Flora Characteristics].

In order to realize the rapid recovery of ANAMMOX sludge bacterial activity after long-term room temperature storage, three groups of reactors were added to ANAMMOX sludge that had been stored without substrate at room temperature (15-30℃) for 9 months. Among the three groups of reactors, comet fiber carrier and K3 carrier were added to R2 and R3 reactors, respectively, as biological carriers. The effects of different carriers on the recovery rate of ANAMMOX sludge bacterial activity were investigated. The results showed that ANAMMOX reactions in the R2 and R3 reactors began taking place on the 8th and 10th day, respectively, with respective TIN removal rates of 82.25% and 80.92%, which were significantly improved compared with that in the R1 reactor, in which no carrier was added (ANAMMOX reaction started occurring on the 15th day with a TIN removal rate of 80.26%). After 42 days with influent, ρ(NH4+-N) and ρ(NO2--N) respectively increased to 300 mg·L-1 and 396 mg·L-1, and the TIN removal rates of the three groups of reactors were respectively 78.96%, 84.92%, and 84.66%. Microbial community structure analysis showed that the relative abundances of ANAMMOX bacteria in the R2 and R3 reactor were respectively 6.85% and 6.06%, two to four times that in the R1 reactor. The predominant ANAMMOX bacteria in the sludge was Candidatus Jettenia, whose relative abundances in the three groups of reactors were respectively 1.62%, 5.74%, and 5.21%. The results show that ANAMMOX biofilm-granular sludge complex systems constructed by adding carriers can considerably shorten the time for recovering ANAMMOX sludge bacterial activity after long-term room temperature storage without substrate. The carriers effectively promoted the relative abundances of ANAMMOX bacteria in the reactors, whereas the promoting effect of comet fiber carrier was slightly more significant than that of the K3 carrier.

One-step self-assembled nanomicelles for improving the oral bioavailability of nimodipine.

Our study aimed to develop a self-assembled nanomicelle for oral administration of nimodipine (NIM) with poor water solubility. Using Solutol(®) HS15, the NIM-loaded self-assembled nanomicelles displayed a near-spherical morphology with a narrow size distribution of 12.57 ± 0.21 nm (polydispersity index =0.071 ± 0.011). Compared with Nimotop(®) (NIM tablets), the intestinal absorption of NIM from NIM nanomicelle in rats was improved by 3.13- and 2.25-fold in duodenum and jejunum at 1 hour after oral administration. The cellular transport of NIM nanomicelle in Caco-2 cell monolayers was significantly enhanced compared to that of Nimotop(®). Regarding the transport pathways, clathrin, lipid raft/caveolae, and macropinocytosis mediated the cell uptake of NIM nanomicelles, while P-glycoprotein and endoplasmic reticulum/Golgi complex (ER/Golgi) pathways were involved in exocytosis. Pharmacokinetic studies in our research laboratory have showed that the area under the plasma concentration-time curve (AUC0-∞) of NIM nanomicelles was 3.72-fold that of Nimotop(®) via oral administration in rats. Moreover, the NIM concentration in the brain from NIM nanomicelles was dramatically improved. Therefore, Solutol(®) HS15-based self-assembled nanomicelles represent a promising delivery system to enhance the oral bioavailability of NIM.

A novel injectable phospholipid gel co-loaded with doxorubicin and bromotetrandrine for resistant breast cancer treatment by intratumoral injection.

Systemically administered anticancer treatments were greatly limited by extensive side effects mainly due to nonspecific distributions in vivo, and multidrug resistance in various tumors. A phospholipids-based in situ-forming gel platform has been developed for the concurrent delivery of doxorubicin (DOX) and bromotetrandrin (W198). Phospholipid gel containing DOX and W198 remained in a solution (sol) state before injection and underwent rapid gelation after injection in vivo. The release of DOX and W198 from phospholipid gel (PG) was sustained in vitro for over 20 days (d). DOX and W198 from PG achieved prolonged release for over two weeks in rats via subcutaneous injection. Compared with repeated injections of free drug, eliminated cardiac toxicity and less bone marrow inhibition were observed for DOX and W198-loaded PG (DOX/W198-PG) in normal rats via subcutaneous injection. Also, a single intratumoral injection of DOX/W198-PG in the resistant MCF-7/Adr xenograft-bearing mice showed much better antitumor efficacy compared to other treatment groups. In sum, DOX/W198-PG was well demonstrated to achieve sustained drug release both in vitro and in vivo with eliminated toxicity and improved antitumor efficacy by reversing the multidrug resistance in breast cancers.

A high-efficiency, low-toxicity, phospholipids-based phase separation gel for long-term delivery of peptides.

Peptide and protein drugs are currently under rapid development attributed to their high potency and efficacy in therapy. Their successful delivery, however, is highly limited by their short half-life, fast degradation and rapid clearance. Here, we present a high content phospholipids-based phase separation gel (PPSG), which is readily injectable due to its low initial viscosity and can rapidly transform into an in situ implant after injection upon exposure to an aqueous environment. A selected model peptide, octreotide acetate, is loaded into PPSG and achieves sustained release profiles for one month in rats. In addition, the local irritation caused by ethanol contained in PPSG is ethanol content-dependent and the irritation of PPSG with 70% phospholipids content can be eliminated by partially replacing ethanol with medium chain triglyceride. The mechanisms underlying phase transition of PPSG are based on water-insolubility of phospholipids. Our findings demonstrate that PPSG is a readily injectable, highly safe and efficient in situ forming implant for sustained delivery of peptides.