The antisense expression of

Although phosphoenolpyruvate carboxylases (PEPCs) are reported to be involved in fatty acid accumulation, nitrogen assimilation, and salt and drought stresses, knowledge regarding PEPC gene functions is still limited, particularly in peanuts (Arachis hypogaea L.). In this study, the antisense expression of the peanut PEPC isoform 1 (AhPEPC1) gene increased the lipid content by 5.7%–10.3%. This indicated that AhPEPC1 might be related to plant lipid accumulation. The transgenic plants underwent more root elongation than the wild-type under salinity stress. Additionally, the specific down regulation of the AhPEPC1 gene improved the salt tolerance in peanuts. This is the first report on the role of PEPC in lipid accumulation and salt tolerance in peanuts.

Structured photocathodes for improved high-energy x-ray efficiency in streak cameras

We have designed and fabricated a structured streak camera photocathode to provide enhanced efficiency for high energy X-rays (1-12 keV). This gold coated photocathode was tested in a streak camera and compared side by side against a conventional flat thin film photocathode. Results show that the measured electron yield enhancement at energies ranging from 1 to 10 keV scales well with predictions, and that the total enhancement can be more than 3×. The spatial resolution of the streak camera does not show degradation in the structured region. We predict that the temporal resolution of the detector will also not be affected as it is currently dominated by the slit width. This demonstration with Au motivates exploration of comparable enhancements with CsI and may revolutionize X-ray streak camera photocathode design.

[Application of robot-assisted surgery in the surgical treatment of head and neck cancer]

In recent years, robot-assisted surgery (RAS) has developed rapidly and become one of the hot topics in clinical research. Compared with traditional surgery, RAS has advantages in terms of minimal invasiveness, aesthetics, and functional preservation, and has been gradually applied in clinical practice such as neurosurgery, urology, and head and neck surgery. In the treatment of head and neck tumors, RAS can effectively minimize the surgical injury and accelerate postoperative recovery. This article reviews the application of RAS in the resection of primary lesions of head and neck tumors, neck dissection, and reconstruction of tissue defects.

Aberrations of volume holographic grating

We discuss the volume holographic grating produced by imperfect plane waves and derive analytical formulas for phase aberrations of the transmitted and diffracted waves at Bragg incidence. With these results, a quantitative analysis of wave-front distortion is made.

Image feature extraction using diameter-limited gradient direction histograms

Features extracted by operators which examine diameter-limited gradient direction histograms are important because they describe images of industrial workpieces efficiently and have the potential for rapid computation via special purpose hardware. When such operators are passed over an image in raster fashion, features such as the following are detected: a strong peak in the direction histogram indicating the presence of a relatively straight edge, a second strong direction indicating a corner, a wide direction group indicating a curved edge, and a uniform distribution of directions over the histogram indicating small holes. Diameter-limited optimization can be used to substantially reduce the number of pixels which have been given feature labels by such operators without losing descriptive power. Feature labels for direction histograms having a second strong direction, a wide direction group, or a uniform distribution might be retained only if all other pixels within a circular aperture have a lower bin value. Pixels with a strong direction label might be retained only if all other pixels within a circular aperture and along the gradient direction have a smaller bin value. Tracking can then be applied to the remaining strong direction pixels in the direction perpendicular to the gradient to achieve representation of edges by endpoints. Experimental results indicate that descriptions which are compatible with human interpretation can be achieved.

The role of ethylene during the infection of Nicotiana tabacum by Colletotrichum destructivum

Two periods of increased ethylene production were observed after inoculation of Nicotiana tabacum by Colletotrichum destructivum. This pathogen exhibits an intracellular hemibiotrophic infection process, with a biotrophic phase followed by a necrotrophic phase. Ethylene production first increased during the biotrophic phase with a peak at 24 h before the necrotrophic phase. A second increase in ethylene occurred late in the necrotrophic phase when the lesions were expanding. Two different 1-aminocyclopropane-1-carboxylic acid synthase genes showed increased expression after the first ethylene peak with a maximum at 24 h before the second ethylene increase. Expression of an 1-aminocyclopropane-1-carboxylic acid oxidase (ACO) gene increased during the first ethylene peak and then declined at the beginning of the second ethylene increase. A second ACO gene showed relatively little change in expression during infection with slightly higher expression at 24 h before the second ethylene increase, and a third ACO gene showed a progressive decline in expression with a major decrease occurring before the second ethylene increase. Inoculation of ethylene-insensitive tobacco with C. destructivum revealed that it was more susceptible than the wild type. The changes in ethylene production and associated gene expression as well as the increased disease susceptibility of ethylene-insensitive tobacco indicate that ethylene plays a role in this interaction, perhaps as a signalling molecule to trigger defense mechanisms.

Mating-Type Genes Control Sexual Reproduction, Conidial Germination, and Virulence in Cochliobolus lunatus

Cochliobolus lunatus (anamorph: Curvularia lunata) is a major pathogenic fungus that causes the Curvularia leaf spot of maize. ClMAT1-1-1 and ClMAT1-2-1, the C. lunatus orthologs of C. heterostrophus ChMAT1-1-1 and ChMAT1-2-1, were investigated in the present study to uncover their functions in C. lunatus. Southern blot analysis showed that these mating-type MAT genes exist in the C. lunatus genome as a single copy. ClMAT1-1-1 and ClMAT1-2-1 were knocked out and complemented to generate ΔClmat1-1-1 and ΔClmat1-2-1 and ΔClmat1-1-1-C and ΔClmat1-2-1-C, respectively. The mutant strains had defective sexual development and failed to produce pseudothecia. There were no significant differences in growth rate or conidia production between the mutant and wild-type strains. However, the aerial mycelia and mycelial dry weight of ΔClmat1-1-1 and ΔClmat1-2-1 were lower than those of wild type, suggesting that MAT genes affect asexual development. ClMAT genes were involved in the responses to cell wall integrity and osmotic adaptation. ΔClmat1-2-1 had a lower conidial germination rate than the wild-type strain CX-3. The virulence of ΔClmat1-2-1 and ΔClmat1-1-1 was also reduced compared with the wild-type. Complementary strains could restore all the phenotypes.

Peroxisomal membrane protein PMP68 of mouse liver: cloning of a cDNA encompassing the nucleotide binding fold and epitope mapping of monoclonal antibodies to the expressed protein

We have isolated and sequenced a cDNA which encodes 376 amino acids toward the carboxy-terminus, and encompassing the putative nucleotide binding fold, of PMP68 (mouse liver peroxisomal integral membrane protein of 68 kDa) the major integral membrane protein of mouse liver peroxisomes. The protein sequence predicted from this cDNA shows 97.9% amino acid identity to this same region of rat liver PMP70, a member of the ATP-binding cassette protein superfamily (K. Kamijo, S. Taketani, S. Yokota, T. Osumi, and T. Hashimoto, 1990, J. Biol. Chem. 265, 4534-4540). The section of the cDNA encoding the hydrophilic and putative cytoplasmic domain of PMP68 was expressed as a recombinant fusion protein in bacteria. Two monoclonal antibodies raised against this protein have been epitope-mapped to peptides generated by cyanogen bromide cleavage of the fusion protein. Antibody 1A4 recognizes a peptide whose sequence contains the first motif of the putative nucleotide binding fold of PMP68, and antibody 8F11 recognizes a carboxy-terminal peptide which includes the second motif of this nucleotide binding fold. These antibodies are expected to be useful in the elucidation of the biological function of this putative membrane transporter.

A dynein heavy chain homologue gene in Hexamita inflata

A gene encoding an unusually small dynein heavy chain homologue, hDYHH, was cloned from the genome of a free-living diplomonad, Hexamita inflata (Hi). The open reading frame (ORF) of hDYHH is 867bp and encodes a polypeptide of 289 amino acids (aa), hDYHH. hDYHH is homologous to the region around the third P-loop ATP-binding site of several dynein heavy chain polypeptides that are around 4000aa. Northern blot analysis showed that hDYHH is expressed in vivo and that the mRNA length (approximately 1.8kb) is consistent with the gene length (1.67kb). Southern blot analysis indicated that there are hDYHH homologues within the Hi genome, possibly including a longer dynein heavy chain gene. An hDYHH homologue was also identified in Hexamita pusilla (Hp). hDYHH is the first full-length protein-encoding gene cloned from Hexamita.

[Oxymatrine inhibits target cell infection in the HCVcc system]

OBJECTIVE

To validate the antiviral effect of oxymatrine against hepatitis C virus (HCV) in the construction of the cell culture-based infectious virus system HCVcc.

METHODS

An HCVcc system was established by infecting Huh7.5.1 cells with the J6 adapted virus (J6cc). Cells of the HCVcc system were then treated with different concentrations of oxymatrine for 24 h, 48 h and 72 h, or left untreated (controls). MTT assay was used to detect effects on proliferation. Real-time quantitative PCR was used to detect effects on HCV mRNA expression level, and immunofluorescence was used to detect effects on HCV protein expression. Data were expressed as mean±standard deviation, and statistically assessed using one-way ANOVA and one-sample t-test.

RESULTS

Treatment with 2, 4, 8 and 12 mg/mL of oxymatrine for 24 h inhibited proliferation of the J6cc-infected cells by 8.4%, 15.2%, 29.6% and 48.6% respectively, 48 h treatment inhibited by 14.3%, 25.7%, 46.1% and 66.4% respectively, and 72 h treatment inhibited by 36.5%, 46.6%, 70.6% and 85.4% respectively. Thus, the effects of oxymatrine were time- and dose-dependent (P < 0.05). The mRNA expression level in the oxymatrine-treated cells of the HCVcc system was 0.59 ± 0.12, which was significantly lower than that in the control cells (P < 0.05). Moreover, as the oxymatrine concentration increased from 2 mg/mL to 12 mg/mL, the expression levels of HCV proteins also showed a decreasing trend.

CONCLUSION

We successfully constructed a J6cc infection HCVcc system and verified the antiviral effect of oxymatrine against HCV.

Investigations of mechanical vibrations for beamlines at the Canadian Light Source

Vibration is often a problem causing poor quality of photon beams at synchrotron radiation facilities, since beamlines are quite sensitive to vibrations. Therefore, vibration analysis and control at synchrotron radiation facilities is crucial. This paper presents investigations on mechanical vibrations at four beamlines and endstations at the Canadian Light Source, i.e. the Canadian Macromolecular Crystallography Facility 08ID-1 beamline, the Hard X-ray MicroAnalysis 06ID-1 beamline, the Resonant Elastic and Inelastic Soft X-ray Scattering 10ID-2 beamline, and the Scanning Transmission X-ray Microscope endstation at the Spectromicroscopy 10ID-1 beamline. This study identifies vibration sources and investigates the influence of mechanical vibrations on beamline performance. The results show that vibrations caused by movable mechanical equipment significantly affect the data acquired from beamlines.

Effects of online cone-beam computed tomography with active breath control in determining planning target volume during accelerated partial breast irradiation

PURPOSE

To test if active breath control during cone-beam computed tomography (CBCT) could improve planning target volume during accelerated partial breast radiotherapy for breast cancer.

METHODS

Patients who were more than 40 years old, underwent breast-conserving dissection and planned for accelerated partial breast irradiation, and with postoperative staging limited to T1-2 N0 M0, or postoperative staging T2 lesion no larger than 3cm with a negative surgical margin greater than 2mm were enrolled. Patients with lobular carcinoma or extensive ductal carcinoma in situ were excluded. CBCT images were obtained pre-correction, post-correction and post-treatment. Set-up errors were recorded at left-right, anterior-posterior and superior-inferior directions. The differences between these CBCT images, as well as calculated radiation doses, were compared between patients with active breath control or free breathing.

RESULTS

Forty patients were enrolled, among them 25 had active breath control. A total of 836 CBCT images were obtained for analysis. CBCT significantly reduced planning target volume. However, active breath control did not show significant benefit in decreasing planning target volume margin and the doses of organ-at-risk when compared to free breathing.

CONCLUSION

CBCT, but not active breath control, could reduce planning target volume during accelerated partial breast irradiation.