H2O2 participates in ABA regulation of grafting-induced chilling tolerance in cucumber.

KEY MESSAGE: Rootstock provides more abscisic acid (ABA) content to scions to increase the chilling tolerance of seedlings. H2O2 is involved in ABA regulation of grafting-induced chilling tolerance of cucumber. Here we examined the role of ABA in the response of grafted cucumber to chilling stress. The data showed chilling induced an increase in leaf and root ABA content and there was a positive correlation between ABA content and the chilling tolerance of the varieties. The increase of ABA content and NCED mRNA abundance in the leaf of both Cs/Cs (self-root) and Cs/Cm (grafted with pumpkin as rootstock) showed a delay under aerial stress compared with those under whole plant and root-zone stress. Intriguingly, an increase in ABA in xylem was found under whole-plant and root-zone chilling stress but was not detected under aerial stress, implying the increases in ABA content in leaves were mainly from root ABA transportation. Compared to Cs/Cs, a higher ABA content and NCED mRNA abundance were observed in Cs/Cm, which showed that Cm could output more ABA than Cs. The removal of endogenous ABA decreased the difference in chilling tolerance induced by Cm, as evidenced by the observed similar oxidative stress levels and photosynthetic capacity between Cs/Cs and Cs/Cm after chilling stress. Moreover, we found that the H2O2 signal in grafted cucumber could respond to chilling stress earlier than the H2O2 signal in self-rooted cucumber. The inhibition of endogenous H2O2 decreased the chilling tolerance of grafted cucumber induced by ABA by reducing photosynthesis and the mRNA abundance of CBF1 and COR. Thus, our results indicate that H2O2, as the downstream signal, participated in the rootstock-induced chilling tolerance of grafted seedlings induced by ABA.

Nonlinear Topological Effects in Optical Coupled Hexagonal Lattice.

Topological physics in optical lattices have attracted much attention in recent years. The nonlinear effects on such optical systems remain well-explored and a large amount of progress has been achieved. In this paper, under the mean-field approximation for a nonlinearly optical coupled boson-hexagonal lattice system, we calculate the nonlinear Dirac cone and discuss its dependence on the parameters of the system. Due to the special structure of the cone, the Berry phase (two-dimensional Zak phase) acquired around these Dirac cones is quantized, and the critical value can be modulated by interactions between different lattices sites. We numerically calculate the overall Aharonov-Bohm (AB) phase and find that it is also quantized, which provides a possible topological number by which we can characterize the quantum phases. Furthermore, we find that topological phase transition occurs when the band gap closes at the nonlinear Dirac points. This is different from linear systems, in which the transition happens when the band gap closes and reopens at the Dirac points.

Auxin acts as a downstream signaling molecule involved in hydrogen sulfide-induced chilling tolerance in cucumber.

MAIN CONCLUSION: This report proves a cross talk between H2S and IAA in cold stress response, which has presented strong evidence that IAA acts as a downstream signal mediating the H2S-induced stress tolerance in cucumber seedlings. We evaluated changes in endogenous hydrogen sulfide (H2S) and indole-3-acetic acid (IAA) emission systems, and the interactive effect of exogenous H2S and IAA on chilling tolerance in cucumber seedlings. The results showed that chilling stress increased the activity and relative mRNA expression of L-/D-cysteine desulfhydrase (L-/D-CD), which in turn induced the accumulation of endogenous H2S. Similarly, the endogenous IAA system was triggered by chilling stress. We found that 1.0 mM sodium hydrosulfide (NaHS, an H2S donor) significantly enhanced the activity of flavin monooxygenase (FMO) and relative expression of FMO-like proteins (YUCCA2), which in turn elevated endogenous IAA levels in cucumber seedlings. However, IAA had little effects on activities of L-/D-CD and endogenous H2S levels. H2S-induced IAA production accompanied by increase in chilling tolerance, as shown by the decrease in stress-induced electrolyte leakage (EL) and reactive oxygen species (ROS) accumulation, and increase in gene expressions and enzyme activities of photosynthesis. 1-naphthylphthalamic acid (NPA, an IAA polar transport inhibitor) declined H2S-induced chilling tolerance and defense genes' expression. However, scavenging of H2S had a little effect on IAA-induced chilling tolerance. These results suggest that IAA acting as a downstream signaling molecule is involved in the H2S-induced chilling tolerance in cucumber seedlings.

Overexpression of transketolase gene promotes chilling tolerance by increasing the activities of photosynthetic enzymes, alleviating oxidative damage and stabilizing cell structure in Cucumis sativus L.

Despite being a key enzyme of Cavin cycle, transketolase (TK) is believed to be related to abiotic resistance in higher plants. However, how TK affects chilling tolerance still remains largely unknown. Here, we describe the effect of overexpression of the Cucumis sativa TK gene (CsTK) on growth, photosynthesis, ROS metabolism and cell ultrastructure under chilling stress. Low temperature led to a decrease of the photosynthetic rate (Pn), the stomatal conductance (Gs), the actual photochemical efficiency (ΦPSII) and the sucrose content, whereas there was an increase of the intercellular CO2 concentration (Ci) and MDA content. These changes were alleviated in the CsTK plants after 5 days of chilling stress, however, inhibition of CsTK showed the opposite results. Furthermore, transgenic plants with overexpression of CsTK showed higher increase in leaf area and dry matter, higher activity of the enzymes and higher increase in the contents of metabolism substance involved in Calvin cycle and reactive oxygen scavenging system as well as lower • OH and H2 O2 content, superoxide anion production rate compared with the control cucumber plants under chilling stress. At the end of the chilling stress, compared to wild-type (WT) which exhibited dramatically destroyed cell ultrastructure, expanded chloroplast, broken cell and chloroplast membranes as well as the disappeared grana lamella, the CsTK sense plants showed a more complete cell ultrastructure, whereas, the damage of the cell ultrastructure was aggravated in CsTK antisense plants. Taken together, these results imply that CsTK promoted chilling tolerance in cucumber plants mainly through increasing the capacity to assimilate carbon, alleviating oxidative damage and stabilizing cell structure.

The prognostic value of circulating tumor cells lacking cytokeratins in metastatic breast cancer patients.

AIM OF STUDY: In this study, we detected epithelial circulating tumor cells (CTCs) that expressed cytokeratins and potential circulating tumor cells (pCTCs) that had lost expression of cytokeratins in metastatic breast cancer (MBC) patients. The aim of the study was to evaluate the prognostic significance of these two kinds of CTCs in MBC patients. MATERIALS AND METHODS: We detected CTCs and pCTCs from 66 MBC patients using MACS immunomagnetic enrichment technology combined with immunocytochemistry (ICC). A cutoff score of 5 CTCs (or pCTCs) was set as a benchmark for prognosis in patients. Progression free survival (PFS) was calculated and analyzed during the following 24 months. RESULTS: We evaluated the sensitivity of this method and recovery rates of the CTCs by spiking experiments. The loss number of tumor cells by our method was 0-15. The population with fewer than 5 CTCs showed significantly higher PFS than the group with 5 or more CTCs. The difference in PFS between the patients with 5 or more pCTCs and those with fewer than 5 pCTCs was statistically significant. The presence of these pCTCs more accurately predicted poor prognosis than the CTCs that express cytokeratins. CONCLUSIONS: There is a subset of CTCs that lose epithelial markers such as pCTCs. Due to the heterogeneity of the expression of epithelial antigens in CTCs, different subtypes of CTCs exist. Independently of CTCs, the groups of patients with pCTCs had poorer prognoses.

Study on application of biological iron sulfide composites in treating vanadium-extraction wastewater containing chromium (VI) and chromium reclamation.

In this study, the Cr(VI)-resistant properties and regeneration characteristics of biological iron sulfide composites were investigated, which consist of sulfate reducing bacteria (SRB) and its in situ synthesized nanosized iron sulfides. Then the application of the composites in treating vanadium-extraction wastewater containing high concentration Cr(VI) and reclaiming Cr were performed. It was found that SRB in composites still survived after being used to treat vanadium-extraction wastewater, which could reduce reaction products Fe3+ and sulphur into Fe2+ and S2 by using them as the electron accepters and thus regenerating biological iron sulfide composites. The SRB also could be resistant to 600 mgl(-1) Cr(VI) and reduce it gradually. Based on the Cr(VI)-resistant properties and regeneration characteristics of the composites, a reduction-regeneration recirculation process for treating vanadium-extraction wastewater and reclamation of Cr was developed. The results indicated that the contaminants in effluent reached the Chinese discharge standard of pollutants for vanadium industry (GB 26452-2011), i.e. the concentration of total Cr(TCr) was less than 0.912 mgl(-1), Cr(VI) was less than 0.017 mgl(-1) and V was less than 0.260 mgl(-1). After 10 cycles of treatment, the Cr2O3 content in sludge reached 41.03%, and the ratio of Cr2O3/FeO was 7.35. The sludge reached the chemical and metallurgical (hydrometallurgy) grade of chromite ore and could be reclaimed.

[Property analysis of nanosized iron sulfide produced by sulfate reducing bacteria and its application in the treatment of wastewater containing high concentration of Cr (VI)].

The properties of novel nanosized iron sulphide produced by sulfate reducing bacteria (SRB) and its application to the removal of Cr (VI) from wastewater were studied. The structural properties were examined by transmission electron microscope (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The influences of pH, temperature and dosage on removal of Cr (VI) from wastewater by nanosized iron sulphide were investigated, and the effect comparison of nanosized iron sulphide and other traditional wastewater treatment was also evaluated. TEM result shows that the length of the nanosized iron sulphide is approximately 45-80 nm, and the ratio of length to width is 10-15. XPS and XRD results indicate that the Fe/S is 1.07-1.11, and the main composition of nanosized iron sulphide is amorphous FeS and mackinawite. While in treating wastewater containing Cr (V), pH, temperature and dosage of nanosized iron sulphide are the main factors to control the reaction. The Cr (VI) reduction rate increases with decrease of pH and increase of dosage and temperature. Among these factors, pH is the most significant influence factor. At 25 degrees C, pH 3, when the mole ratio of nanosized iron sulphide to chromium (VI) reaches 1.17/1, wastewater containing Cr (VI) 0.03 mol/L can be treated to meet the discharge standard within 10 min. Moreover, in treating wastewater containing Cr (VI), compared with commercial iron sulfide (AR.), nanosized iron sulphide has advantages of low dosage and short treatment time, and compared to conventional biological treatment by SRB, nanosized iron sulphide has advantages of low effluent COD and small amount of sludge.

[Application of distortion product otoacoustic emissions in detection of pseudohypacusis and exaggerated hearing loss].

OBJECTIVE: To explore the role of differential diagnosis of distortion product otoacoustic emissions (DPOAE) in pseudohypacusis and exaggerated hearing loss. METHOD: Detection and analysis of DPOAE were made by ILO96 Otodynamics Analyzer in the patients complaining of post-traumatic hearing loss and in cooperative in pure tone threshold (PTT) examination. RESULT: The detective results of DPOAE in 102 patients (121 ears) in cooperative in PTT examination revealed that pseudohypacusis was 66.12% (80/121 ears), exaggerated hearing loss was 33.88% (41/121 ears). The reactive threshold value determined by auditory brainstem response (ABR) in these patients confirmed that the results of DPOAE were objective and reliable. CONCLUSION: DPOAE can be used as a routine examination method in differential diagnosis of the post-traumatic hearing loss. It gives an objective and reliable diagnosis and differential diagnosis for the pseudohypacusis and exaggerated hearing loss.

[Auditory neuropathy in children(analysis of 14 cases)].

OBJECTIVE: To study the clinic findings and the audiological characteristics of auditory neuropathy in children. METHOD: Clinical findings and systemic audiometry were analyzed in 14 cases(28 ears) of auditory neuropathy in children. RESULT: In 14 cases the primary onset age was 7 approximately to 13 year-old,4 male and 10 female. 7 cases had differential pitch tinnitus,mainly low pitch with poor speech discrimination. 1 case manifested peripheral neuropathy symptoms at 1 year after diagnosis. Audiograms of pure tone threshold (PTT) showed various curves including ascending slope, spoon, peak, lain letter S, letter W, gentle slope. Both ascending slope and spoon were 53.57% (15/28 ears). PTT revealed a elevated range from mild to moderate degrees. There was no significant difference between the cours for 0.5 approximately 1.0 year and 1.5 approximately 2.0 years ( t =0.24, P >0.05). Either the acoustic reflex (AR) was absent or the AR threshold was elevated. Speech discrimination scores (SDS) were 0% approximately 46%, average (14.64+/-15.42) %. Auditory brainstem response (ABR) was absent or severely abnormal. Prevalence of distortion product otoacoustic emissions (DPOAE) were 100%, amplitude of DPOAE was normal, which could not be suppressed by contralateral white noise. Prevalence of spontaneous otoacoustic emissions (SOAE) were 82.14% (23/28 ears). CONCLUSION: Audiological characteristics in pediatric auditory neuropathy is obviously. Systemic audiometry has important clinical signification in recognition, diagnosis and research of auditory neuropathy.