Silencing of the major salt-dependent isoform of pectinesterase in tomato alters fruit softening

Pectinesterase (PE; E.C. 3.1.1.11) is an enzyme responsible for the demethylation of galacturonyl residues in high-molecular-weight pectin and is believed to play an important role in cell wall metabolism. In this study, Pmeu1, a ubiquitously expressed PE gene, has been characterized by antisense suppression in tomato (Solanum lycopersicum). Transgenic tomato plants showed reduced PE activity levels in both green fruit and leaf tissue to around 65% and 25% of that found in wild-type plants, respectively. Pmeu1 was observed to encode a salt-dependent PE isoform that correlated with PE1 as previously described in fruit tissue. Silencing of Pmeu1 did not result in any detectable phenotype within the leaf tissue despite the gene product representing the major isoform in this tissue. In comparison, silencing in fruit resulted in an enhancement to the rate of softening during ripening. The role of PMEU1 in fruit ripening is discussed.     

Survey for zoonotic liver and intestinal trematode metacercariae in cultured and wild fish in An Giang Province, Vietnam

Although Vietnam has a high risk of fishborne zoonotic trematode (FZT) infections for humans, little information exists on the epidemiology of these infections in the country's fish. Because of the importance of cultured catfish and snakehead production in An Giang province, a major production area in the Mekong Delta of Vietnam, a survey for FZTs was carried out in randomly selected fish farms between June 2005 and March 2006. For comparison, wild fish from the same area were also surveyed. A total of 852 cultured fish from 4 districts were collected and examined by pepsin digestion to determine their FZT infection status. In Tra catfish, the prevalence of all types of metacercariae was 2.6%, of which the prevalence of Haplorchis pumilio was 0.7%. The overall prevalence of metacercariae in wild fish was 30.6%, of which 10.3% harbored zoonotic species: H. pumilio (2.8%) and Procerovum sp. (5.6%). The prevalence of Opisthorchis metacercariae, which were diagnosed as O. viverrini, was 1.9%. No metacercariae were found in cultured snakehead fish, although wild-caught snakehead fish had a FZT prevalence of 10.3%: 5.1% were O. viverrini 2.6% H. pumilio and 2.6% were Procerovum sp. These are the first reports of H. pumilio, Procerovum sp., and O. viverrini metacercariae in Vietnamese fish. These results indicate that consumption of improperly prepared fish represents a significant risk of acquiring FZTs in this south Vietnam region.     

Alcohol dependence patterns and their impact on New York City

As a follow-up to a national survey by the Community Anti-Drug Coalitions of America (CADCA), an expert panel was convened to discuss local alcoholism data from New York, NY. The impact of alcoholism on the US economy is estimated at $185 billion annually. About 15% of New Yorkers drink alcohol excessively, with the highest percentage in Manhattan (22%). Over 135,000 New York City residents are admitted for alcohol treatment. Alcohol dependency is highest among whites (21%), followed by Latinos (14.8%) and African Americans (11%). Despite lower levels of excessive drinking, African-American and Latino New Yorkers are more likely than white New Yorkers to be hospitalized or die as a result of excessive drinking. The barriers to overcome are the lack of information on treatment options, the stigma of alcoholism, the lack of physician education, and a limited number of treatment facilities/personnel. Patients need behavioral counseling, a commitment to treatment, and compliance with medication if they are to succeed in treatment.     

Impact of arsenite and its methylated metabolites on PARP-1 activity, PARP-1 gene expression and poly(ADP-ribosyl)ation in cultured human cells

The underlying mechanisms of arsenic carcinogenicity are still not fully understood. Mechanisms currently discussed include the induction of oxidative DNA damage and the interference with DNA repair pathways. Still unclear is the role of biomethylation, which has long been considered to be one major detoxification process. Methylated arsenicals have recently been shown to interfere with DNA repair in cellular and subcellular systems, but up to now no DNA repair protein has been identified being particular sensitive towards methylated arsenicals in cultured cells. Here we report that the trivalent methylated metabolites MMA(III) and DMA(III) inhibit poly(ADP-ribosyl)ation in cultured human HeLa S3 cells at concentrations as low as 1nM, thereby showing for the first time an inactivation of an enzymatic reaction related to DNA repair by the trivalent methylated arsenicals at very low environmentally relevant concentrations. In contrast the pentavalent metabolites MMA(V) and DMA(V) showed no such effects up to high micromolar concentrations. All investigated arsenicals did not alter gene expression of PARP-1. However, all trivalent arsenicals were able to inhibit the activity of isolated PARP-1, indicating that the observed decrease in poly(ADP-ribosyl)ation in cultures human cells, predominantly mediated by PARP-1, is likely due to changes in the activity of PARP-1. Since poly(ADP-ribosyl)ation plays a major role in DNA repair, cell cycle control and thus in the maintenance of genomic stability, these findings could in part explain DNA repair inhibition and the genotoxic and carcinogenic effects of arsenic.     

Dosimetric and Monte Carlo verification of jaws-only IMRT plans calculated by the Collapsed Cone Convolution algorithm for head and neck cancers

AimThe aim of this study is to verify the Prowess Panther jaws-only intensity modulated radiation therapy (JO-IMRT) treatment planning (TP) by comparing the TP dose distributions for head-and-neck (H&N) cancer with the ones simulated by Monte Carlo (MC).BackgroundTo date, dose distributions planned using JO-IMRT for H&N patients were found superior to the corresponding three-dimensional conformal radiotherapy (3D-CRT) plans. Dosimetry of the JO-IMRT plans were also experimentally verified using an ionization chamber, MapCHECK 2, and Octavius 4D and good agreements were shown.Materials and methodsDose distributions of 15 JO-IMRT plans of nasopharyngeal patients were recalculated using the EGSnrc Monte Carlo code. The clinical photon beams were simulated using the BEAMnrc. The absorbed dose to patients treated by fixed-field IMRT was computed using the DOSXYZnrc. The simulated dose distributions were then compared with the ones calculated by the Collapsed Cone Convolution (CCC) algorithm on the TPS, using the relative dose error comparison and the gamma index using global methods implemented in PTW-VeriSoft with 3%/3 mm, 2%/2 mm, 1%/1 mm criteria.ResultsThere is a good agreement between the MC and TPS dose. The average gamma passing rates were 93.3 ± 3.1%, 92.8 ± 3.2%, 92.4 ± 3.4% based on the 3%/3 mm, 2%/2 mm, 1%/1 mm criteria, respectively.ConclusionsAccording to the results, it is concluded that the CCC algorithm was adequate for most of the IMRT H&N cases where the target was not immediately adjacent to the critical structures.     

Tunable Hybrid Gap Surface Plasmon Polariton Waveguides with Ultralow Loss Deep-Subwavelength Propagation

Exploring hybrid gap surface plasmon polariton waveguides (HGSPPWs) is an important milestone in developing the next-generation, nanoscale integrated photonic circuit technology. To advance their potential applications, HGSPPWs are required to have tunable capability, highly reliable, simple fabrication process, and feasible integration. In this paper, we propose two tunable HGSPPWs fulfilling the requirements. The proposed HGSPPWs consist of a metallic wedge laterally coupled with a dielectric waveguide. The modal characteristics of HGSPPWs are investigated at the optical telecommunication wavelength, which shows the modal characteristics could be effectively controlled by tuning the key geometry parameters and structure of HGSPPWs. The propagation length could achieve the centimeter scale while maintaining the propagation mode size at the deep-subwavelength scale (~ λ²/10⁵). The studies on fabrication tolerance and waveguide crosstalk show their robust property for practical implementations. The effective tunable mechanism is also proposed and studied, which shows remarkable feasibility to realize multifunctional plasmon-based photonic components. Compared with the conventional HGSPPWs, the proposed HGSPPWs exhibit superior features in ultralow loss deep-subwavelength light guiding, are highly reliable, and are easy to integrate.

     

Occurrence of Melibiose‐Containing Glycosphingolipids in a Sample of a Sponge‐Coral Association (Desmapsamma anchorata/Carijoa riisei)

In our research on biologically active compounds from Vietnamese marine invertebrates, rare melibiose‐containing glycosphingolipids were found in a sample of a sponge‐coral association (Desmapsamma anchorata/Carijoa riisei). Melibiosylceramides were analyzed as constituents of some multi‐component RP‐HPLC fractions, and the structures of 14 new ( 1b , 3b , 4a – 4c , 6a – 6c , 8b , 9a , 9b , 10b , 11a , 11b ) and five known ( 2b , 5a – 5c , 7b ) natural compounds were elucidated using NMR, mass spectrometry, optical rotation, and chemical transformations. These α‐d ‐Galp‐(1→6)‐β‐d ‐Glcp‐(1 1)‐ceramides (presumably sponge‐derived compounds) were shown to contain phytosphingosine‐type n‐t17:0 ( 1 ), (6E)‐n‐t17:1 ( 2 ), i‐t17:0 ( 3 ), n‐t18:0 ( 4 ), (6E)‐n‐t18:1 ( 5 ), i‐t18:0 ( 6 ), (6E)‐i‐t18:1 ( 7 ), i‐t19:0 ( 8 ), (6E)‐i‐t19:1 ( 9 ), ai‐t19:0 ( 10 ), and (6E)‐ai‐t19:1 ( 11 ) backbones N‐acylated with saturated straight‐chain (2R)‐2‐hydroxy C₂₁ ( a ), C₂₂ ( b ), and C₂₃ ( c ) acids. Characteristic trends in the fragmentations of the terminal parts of tetraacetylated normal‐chain and iso‐ and anteiso‐branched sphingoid bases were observed using GC/MS. The total sum of melibiosylceramides and compound 5b caused a reduction in colony formation of human melanoma cells.