Heavy metal tolerance and accumulation of Triarrhena sacchariflora, a large amphibious ornamental grass

In this study, we report the tolerance and accumulation of Triarrhena sacchariflora to copper (Cu) and cadmium (Cd). The results show that T. sacchariflora had strong tolerance to Cu and Cd stress. The tolerance indexes (TI) were greater than 0.5 for all treatments. The bioconcentration factors (BCFs) to Cu and Cd were both above 1.0. The accumulation ability of roots was stronger than that of shoots, and ranges of BCF to Cu and Cd in roots were 37.89-79.08 and 83.96-300.57, respectively. However, the translocation ability to Cu and Cd was weak, with more than 86% of Cu or Cd accumulated in roots, suggesting an exclusion strategy for heavy metal tolerance. The uptake efficiency (UE) and translocation efficiency (TE) to Cu and Cd increased linearly as the Cu and Cd concentration in the substrate increased. UE was higher than TE, with a maximum of 2,118.90 μg g(-1) root dry weight (DW) (50 mg L(-1) Cu) and 1,847.51 μg g(-1) root DW (20 mg L(-1)Cd), respectively. The results indicate that T. sacchariflora is a Cu- and Cd-tolerant non-hyperaccumulator plant, suggesting that T. sacchariflora could play an important role in phytoremediation in areas contaminated with Cu and Cd.

Prospective feasibility study on the use of multiband mucosectomy for endoscopic resection of early squamous neoplasia in the esophagus

BACKGROUND AND STUDY AIMS

Endoscopic resection for esophageal squamous high-grade intraepithelial neoplasia (HGIN) or intramucosal cancer (esophageal squamous cell carcinoma [ESCC]) with the endoscopic resection cap technique is technically difficult, and requires submucosal lifting and multiple snares for piecemeal resections. Multiband mucosectomy (MBM) is an easy-to-use endoscopic resection technique and may be the modality of choice in China, where ESCC is extremely prevalent. The aim of the current study was to prospectively evaluate MBM for piecemeal endoscopic resection of squamous neoplasia of the esophagus.

METHODS

Patients with HGIN/ESCC and no signs of submucosal invasion or metastatic disease were included in the study. Lesions were delineated using electrocoagulation and resected using the MBM technique. Endpoints were procedure time, endoscopic radicality, complications, histology of the endoscopic resection specimens, and absence of HGIN/ESCC at the endoscopic resection scar during follow-up.

RESULTS

A total of 41 patients (26 male; mean age 61 years) underwent MBM; all lesions were visible with white light endoscopy (median length 5 cm, interquartile range [IQR] 4 - 6 cm; median circumferential extent 42 %, IQR 25 - 50 %). Median procedure time was 12 minutes (IQR 8 - 24 minutes). Median number of resections was 5 (IQR 3 - 6). Endoscopic complete resection was achieved in all lesions. There was one perforation, which was treated by application of clips. No other complications were observed. The worst histology was ESCC (n = 19), HGIN (n = 17), middle grade intraepithelial neoplasia (n = 4), and normal squamous epithelium (n = 1). Endoscopic follow-up at 3 months showed HGIN at the endoscopic resection scar in two patients, which was effectively treated endoscopically, and showed normal squamous epithelium in all patients at final follow-up (median 15 months, IQR 12 - 24 months).

CONCLUSION

This first prospective study on MBM for piecemeal endoscopic resection of early esophageal squamous neoplasia showed that MBM was effective for the complete removal of lesions with short procedure time, few complications, effective histological assessment of resected specimens, and durable treatment effect.

Secondhand cigarette smoke exposure causes upregulation of cerebrovascular 5-HT(1) (B) receptors via the Raf/ERK/MAPK pathway in rats

AIM

Cigarette smoke exposure increases the risk of stroke. Upregulation of 5-hydroxytryptamine 1B (5-HT(1) (B) ) receptors is associated with the pathogenesis of cerebral ischaemia. This study examined the hypothesis that the expression of 5-HT(1) (B) receptors is altered in brain vessels after secondhand smoke (SHS) exposure.

METHODS

Rats were exposed to SHS in vivo for 200 min daily for 8 weeks. The contractile responses of isolated cerebral arteries were studies by a sensitive myograph. The mRNA and protein expression for 5-HT(1) (B) receptors were examined by real-time PCR, Western blot and immunofluorescence respectively. In addition, the phosphorylation of Raf/extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinases (MAPK) pathway was evaluated.

RESULTS

The results showed that SHS exposure shifted the 5-HT(1) (B) receptor-mediated concentration-contraction curve towards the left with a markedly increased maximal contraction. Furthermore, there were significant elevations in mRNA level and protein expression of 5-HT(1) (B) receptors in SHS-exposed rats. Immunostaining revealed that the 5-HT(1) (B) receptors were localized to the smooth muscle cells of cerebral arteries. SHS was also found to induce the phosphorylation of Raf-1 and ERK1/2 proteins. The administration of a Raf-1 inhibitor GW5074 attenuated the 5-HT(1) (B) receptor upregulation.

CONCLUSION

Secondhand smoke exposure upregulates cerebrovascular 5-HT(1) (B) receptors in rats. The receptor upregulation is associated with Raf/ERK/MAPK activation.

Knockdown of AXL receptor tyrosine kinase in osteosarcoma cells leads to decreased proliferation and increased apoptosis

Dysregulation of the Axl receptor tyrosine kinase (RTK) has been implicated in the development and progression of a variety of malignancies. Axl is known to activate strong anti-apoptotic signaling pathways that promote oncogenesis. However, the role of Axl plays in osteosarcoma (OS) remains elusive. The present study aimed to investigate the clinical significance and function of Axl in human OS. Forty cases of OS and corresponding adjacent non-cancerous tissues (ANCT) were collected. The expression of Axl was assessed using immunohistochemical assay through tissue microarray procedure. A loss-of-function experiment was performed to investigate the effects of small hairpin RNA (shRNA)-mediated knockdown of Axl on the expression of p-AKT, poly ADP-ribose polymerase (PARP) and Ki-67, the proliferative activities, indicated by MTT assay, and the apoptotic index in OS MG-63 cells. As a result, the expression of Axl was found in OS tissues with higher strong reactivity rate, compared with the ANCT (75.0 percent vs 20.0 percent, P=0.000), but it did not associate with the age, gender, tumor size, TNM staging and distant metastases (each Pgreater than0.05). Furthermore, knockdown of Axl inhibited the proliferative activities and induced apoptosis in MG-63 cells with decreased expression of p-AKT, and Ki-67 and increased expression of PARP. In conclusion, our findings suggest that Axl is highly expressed in most of the OS tissues compared with the ANCT, and knockdown of Axl inhibits proliferation and induces apoptosis of OS cells possibly through downregulation of the AKT pathway, suggesting that our findings may provide new insights into the potential therapeutic target for cancer.

Intense nanosecond pulsed electric fields promote cancer cell apoptosis through centrosome-dependent pathway involving reduced level of PLK1

BACKGROUND

Intense nanosecond pulsed electric fields (nsPEFs) have been known to promote apoptosis without physically changing membrane structure or damaging morphology of tumor cells. To determine the contribution of centrosome to the progression of apoptosis by nsPEFs, HeLa cells were exposed to high intensity (6 kV/cm) nsPEFs (8-32 ns) in normal culture condition and cell biology and molecular parameters of cells were investigated.

MATERIALS AND METHODS

Apoptotic cell death was identified by TUNEL assay after being exposed to the nsPEFs with various pulse durations, while immunofluorescent staining was performed to detect the number and distribution of centrosomes. To clarify whether nsPEFs-induced centrosome over-duplication is the consequence of DNA damage, we used comet assay to detect simultaneous DNA damage. And additionally Western Blot was used to detect PLK1 protein level to explore the correlation between apoptotic cell death and nsPEFs-induced centrosome over-duplication. Correlation between nsPEFs and molecular parameters was statistically analyzed.

RESULTS

NsPEFs induced a clear apoptosis reaching a maximum at 24ns, 24h after exposure (p < 0.05), where DNA fragmentation and over-duplicated centrosomes were observed. This apoptosis may be promoted in a time- and pulse duration-dependent manner. Polo-like kinase (PLK1) protein levels were significantly decreased by such nsPEFs (p < 0.05). Control treatment without the nsPEFs did not cause any damage to the cultured HeLa cells.

CONCLUSIONS

Intense nsPEFs promote cell apoptosis through a centrosome-mediated pathway involving a reduction in the level of PLK1, which may provide new therapeutic targets for human cancer treatment.

P2Y12 protects platelets from apoptosis via PI3k-dependent Bak/Bax inactivation

BACKGROUND

Platelet ADP receptor P2Y(12) is well studied and recognized as a key player in platelet activation, hemostasis and thrombosis. However, the role of P2Y(12) in platelet apoptosis remains unknown.

OBJECTIVES

To evaluate the role of the P2Y(12) receptor in platelet apoptosis.

METHODS

We used flow cytometry and Western blotting to assess apoptotic events in platelets treated with ABT-737 or ABT-263, and stored at 37°C, combined with P2Y(12) receptor antagonists or P2Y(12) -deficient mice.

RESULTS

 P2Y(12) activation attenuated apoptosis induced by ABT-737 in human and mouse platelets in vitro, evidenced by reduced phosphatidylserine (PS) exposure, diminished depolarization of mitochondrial inner transmembrane potential (ΔΨm) and decreased caspase-3 activation. Through increasing the phosphorylation level of Akt and Bad, and changing the interaction between different Bcl-2 family proteins, P2Y(12) activation inactivated Bak/Bax. This antiapoptotic effect could be abolished by P2Y(12) antagonism or PI3K inhibition. We also observed the antiapoptotic effect of P2Y(12) activation in platelets stored at 37°C. P2Y(12) activation improved the impaired activation responses of apoptotic platelets stressed by ABT-737. In platelets from mice dosed with ABT-263 in vivo, clopidogrel or deficiency of P2Y(12) receptor enhanced apoptosis along with increased Bak/Bax activation.

CONCLUSIONS

This study demonstrates that P2Y(12) activation protects platelets from apoptosis via PI3k-dependent Bak/Bax inactivation, which may be physiologically important to counter the proapoptotic challenge. Our findings that P2Y(12) blockade exaggerates platelet apoptosis induced by ABT-263 (Navitoclax) also imply a novel drug interaction of ABT-263 and P2Y(12) antagonists.

Fine mapping and characterization of BPH27, a brown planthopper resistance gene from wild rice (Oryza rufipogon Griff.)

The brown planthopper (Nilaparvata lugens Stål; BPH) is one of the most serious rice pests worldwide. Growing resistant varieties is the most effective way to manage this insect, and wild rice species are a valuable source of resistance genes for developing resistant cultivars. BPH27 derived from an accession of Guangxi wild rice, Oryza rufipogon Griff. (Accession no. 2183, hereafter named GX2183), was primarily mapped to a 17-cM region on the long arm of the chromosome four. In this study, fine mapping of BPH27 was conducted using two BC(1)F(2) populations derived from introgression lines of GX2183. Insect resistance was evaluated in the BC(1)F(2) populations with 6,010 individual offsprings, and 346 resistance extremes were obtained and employed for fine mapping of BPH27. High-resolution linkage analysis defined the BPH27 locus to an 86.3-kb region in Nipponbare. Regarding the sequence information of rice cultivars, Nipponbare and 93-11, all predicted open reading frames (ORFs) in the fine-mapping region have been annotated as 11 types of proteins, and three ORFs encode disease-related proteins. Moreover, the average BPH numbers showed significant differences in 96-120 h after release in comparisons between the preliminary near-isogenic lines (pre-NILs, lines harboring resistance genes) and BaiR54. BPH growth and development were inhibited and survival rates were lower in the pre-NIL plants compared with the recurrent parent BaiR54. The pre-NIL exhibited 50.7% reductions in population growth rates (PGR) compared to BaiR54. The new development in fine mapping of BPH27 will facilitate the efforts to clone this important resistant gene and to use it in BPH-resistance rice breeding.

Controlled clockwise and anticlockwise rotational switching of a molecular motor

The design of artificial molecular machines often takes inspiration from macroscopic machines. However, the parallels between the two systems are often only superficial, because most molecular machines are governed by quantum processes. Previously, rotary molecular motors powered by light and chemical energy have been developed. In electrically driven motors, tunnelling electrons from the tip of a scanning tunnelling microscope have been used to drive the rotation of a simple rotor in a single direction and to move a four-wheeled molecule across a surface. Here, we show that a stand-alone molecular motor adsorbed on a gold surface can be made to rotate in a clockwise or anticlockwise direction by selective inelastic electron tunnelling through different subunits of the motor. Our motor is composed of a tripodal stator for vertical positioning, a five-arm rotor for controlled rotations, and a ruthenium atomic ball bearing connecting the static and rotational parts. The directional rotation arises from sawtooth-like rotational potentials, which are solely determined by the internal molecular structure and are independent of the surface adsorption site.

Post-treatment human papillomavirus status and recurrence rates in patients treated with loop electrosurgical excision procedure conization for cervical intraepithelial neoplasia

PURPOSE OF INVESTIGATION

The aim of the study was to evaluate the rate of human papillomavirus (HPV) infection clearance after loop electrosurgical excision (LEEP) procedure conization for cervical intraepithelial neoplasia (CIN) and the factors related to such clearance and to assess the relation between HPV and recurrence.

MATERIALS AND METHODS

A total 141 patients who underwent LEEP owing to high-risk human papillomavirus (HR-HPV) associated with CIN were involved this study. All patients with negative margins on LEEP specimens were followed up with HPV testing and cervical smear after three, six, nine, and 12 months post-treatment. If necessary, cervical biopsy under colposcopy was performed.

RESULTS

LEEP can effectively eliminate HPV infection. Most patients cleared HPV infection within six months. The persistent HPV infection rates were 44.6%,10.6%, 5.7%, and 2.1% after three, six, nine, and 12 months, respectively. The clearance rates were significantly slower in patients with HPV 16 infection, and not differ significantly by age, parity, and pathologic degree. Patients with persistent HR-HPV infection after treatment had a significantly higher risk for recurrence/residual after LEEP compared to patients with negative HPV infection.

CONCLUSION

The authors concluded that patients who were positive for HPV infection, especially for HPV 16, should be followed up closely after treatment.