Comparative compositional analysis of cassava brown streak disease resistant 4046 cassava and its non-transgenic parental cultivar

Compositional analysis is an important component of an integrated comparative approach to assessing the food and feed safety of new crops developed using biotechnology. As part of the safety assessment of cassava brown streak disease resistant 4046 cassava, a comprehensive assessment of proximates, minerals, amino acids, fatty acids, vitamins, anti-nutrients, and secondary metabolites was performed on leaf and storage root samples of 4046 cassava and its non-transgenic parental control, TME 204, collected from confined field trials in Kenya and Uganda over two successive cropping cycles. Among the 100 compositional components that were assessed in samples of 4046 and control TME 204 cassava roots (47 components) and leaves (53 components), there were no nutritionally relevant differences noted. Although there were statistically significant differences between the transgenic and control samples for some parameters, in most cases the magnitudes of these differences were small (<20%), and in every case where comparative literature data were available, the mean values for 4046 and control cassava samples were within the range of normal variation reported for the compositional component in question. Overall, no consistent patterns emerged to suggest that biologically meaningful adverse changes in the composition or nutritive value of the leaves or storage roots occurred as an unintended or unexpected consequence of the genetic modification resulting in 4046 cassava. The data presented here provide convincing evidence of the safety of 4046 cassava with respect to its biochemical composition for food and feed, and it could be considered as safe as its non-transgenic control.

DNMT3B Oncogenic Activity in Human Intestinal Cancer Is Not Linked to CIMP or BRAFV600E Mutation

Approximately 10% of human colorectal cancer (CRC) are associated with activated BRAFV600E mutation, typically in absence of APC mutation and often associated with a CpG island methylator (CIMP) phenotype. To protect from cancer, normal intestinal epithelial cells respond to oncogenic BRAFV600E by activation of intrinsic p53 and p16-dependent tumor suppressor mechanisms, such as cellular senescence. Conversely, CIMP is thought to contribute to bypass of these tumor suppressor mechanisms, e.g. via epigenetic silencing of tumor suppressor genes, such as p16. It has been repeatedly proposed that DNMT3B is responsible for BRAFV600E-induced CIMP in human CRC. Here we set out to test this by in silico, in vitro, and in vivo approaches. We conclude that although both BRAFV600E and DNMT3B harbor oncogenic potential in vitro and in vivo and show some evidence of cooperation in tumor promotion, they do not frequently cooperate to promote CIMP and human intestinal cancer.

A prospective comparison of the prognostic value of tumor- and patient-related factors in patients undergoing potentially curative surgery for pancreatic ductal adenocarcinoma

BACKGROUND

Outcome prediction after resection with curative intent for pancreatic ductal adenocarcinoma remains a challenge. There is increasing evidence that the presence of an ongoing systemic inflammatory response is associated with poor outcome in patients undergoing resection for a variety of common solid tumors. Our aim was to prospectively evaluate the prognostic value of tumor- and patient-related factors including the systemic inflammatory response in patients undergoing potentially curative surgery for pancreatic ductal adenocarcinoma of the head of pancreas.

METHODS

The prognostic impact of tumor factors such as stage and host factors, including the systemic inflammatory response (modified Glasgow Prognostic Score [mGPS]), were evaluated in a prospective study of 135 patients who underwent elective pancreaticoduodenectomy for pancreatic ductal adenocarcinoma from January 2002 to April 2009.

RESULTS

In addition to the established tumor-related pathological factors (in particular margin involvement; hazard ratio [HR] 2.82, 95% confidence interval [CI] 1.65-4.84, P < 0.001), an elevated mGPS (HR 2.26, 95% CI 1.43-3.57, P < 0.001) was independently associated with lower overall survival after pancreaticoduodenectomy. Additionally, in an adjuvant therapy subgroup of 74 patients, both margin involvement and an elevated mGPS remained independently associated with reduced overall survival.

CONCLUSIONS

We have prospectively validated the influence of tumor-related and patient-related factors. Margin involvement and the preoperative mGPS were the most important determinants of overall survival in patients undergoing potentially curative pancreaticoduodenectomy. Furthermore, both had independent prognostic value in those patients receiving adjuvant chemotherapy. In the future, this may be considered a stratification factor for entry onto therapeutic trials.

Perception of the voicing distinction in speech produced during simultaneous communication

This study investigated the perception of voice onset time (VOT) in speech produced during simultaneous communication (SC). Four normally hearing, experienced sign language users were recorded under SC and speech alone (SA) conditions speaking stimulus words with voiced and voiceless initial consonants embedded in a sentence. Twelve hearing-impaired listeners participated, with three of them randomly assigned to audit the speech sample provided by each one of the four speakers under the SC and SA conditions. In addition, 24 normal hearing listeners were randomly assigned to audit the speech samples produced by the four speakers under the SC and SA conditions, three listeners in noise and three listeners in filtered listening conditions for each of the four speakers. Although results indicated longer sentence durations for SC than SA, results showed no difference in the perception of the voicing distinction for speech produced during SC versus speech produced during SA under either the noise or filtered listening condition, or any difference in perception for the hearing-impaired listeners. This conclusion is consistent with previous research indicating that temporal alterations produced by SC do not produce degradation of temporal or spectral cues in speech or disruption of the perception of specific English phoneme segments.

LEARNING OUTCOMES

As a result of this activity, the participant will be able to: (1) describe simultaneous communication; (2) explain the role of simultaneous communication in communication with persons who are hearing-impaired; (3) discuss methods of measuring perception of voice onset time with hearing-impaired listeners and with hearing listeners under filtered and noise conditions; and (4) specify the ability of listeners to perceive the voicing distinction in speech produced during simultaneous communication.

Effects of noise and filtering on the intelligibility of speech produced during simultaneous communication

This study investigated the effects of noise and filtering on the intelligibility of speech produced during simultaneous communication (SC). Four normal hearing, experienced sign language users were recorded under SC and speech alone (SA) conditions speaking Boothroyd's forced-choice phonetic contrast material designed for measurement of speech intelligibility. Twenty-four normal hearing listeners audited the speech samples produced by the four speakers under the SC and SA conditions, three listeners in noise and three listeners in filtered listening conditions for each of the four speakers. Although results indicated longer sentence durations for SC than SA, the data showed no difference in the intelligibility of speech produced during SC versus speech produced during SA under either the noise or filtered listening condition, nor any difference in pattern of phonetic contrast recognition errors between the SA and SC speech samples in either listening condition. This conclusion is consistent with previous research indicating that temporal alterations produced by SC do not produce degradation of temporal or spectral cues to speech intelligibility or disruption of the perception of specific English phoneme segments.

LEARNING OUTCOMES

As a result of this activity, the participant will be able to (1) describe simultaneous communication; (2) explain the role of simultaneous communication in communication with children who are deaf; (3) discuss methods of measuring speech intelligibility under filtered and noise conditions; and (4) specify the ability of listeners to perceive speech produced during simultaneous communication under noise and filtered listening conditions.

Intelligibility of speech produced during simultaneous communication

This study investigated the overall intelligibility of speech produced during simultaneous communication (SC). Four hearing, experienced sign language users were recorded under SC and speech alone (SA) conditions speaking Boothroyd's (1985) forced-choice phonetic contrast material designed for measurement of speech intelligibility. Twelve hearing-impaired listeners participated, with three of them randomly assigned to audit the speech sample provided by each one of the four speakers under the SC and SA conditions. Although results indicated longer sentence durations for SC than SA, results showed no difference in the overall intelligibility of speech produced during SC versus speech produced during SA, nor any difference in pattern of phonetic contrast recognition errors during SC. This conclusion is consistent with previous research indicating that temporal alterations produced by SC do not produce degradation of temporal or spectral cues in speech or disruption of the perception of specific English phoneme segments.

LEARNING OUTCOMES

As a result of this activity, the participant will be able to (1) describe simultaneous communication; (2) explain the role of simultaneous communication in communication with children who are deaf; (3) discuss methods of measuring speech intelligibility; and (4) specify the ability of listeners to perceive speech produced during simultaneous communication.

Resistance to tomato spotted wilt virus infection in transgenic tobacco expressing the viral nucleocapsid gene

A recombinant plasmid containing the entire tomato spotted with virus (TSWV) nucleocapsid gene, with the exception of nucleotide encoding three N-terminal amino acids, was isolated by screening a complementary DNA library, prepared against random primed viral RNA, using a specific monoclonal antibody. The insert contained in plasmid pTSW1 was repaired and amplified by polymerase chain reaction, and the complete nucleocapsid protein gene was introduced into Nicotiana tabacum 'Samsun' by leaf disk transformation using Agrobacterium tumefaciens. Transgenic plants expressing the viral nucleocapsid protein were resistant to subsequent infection following mechanical inoculation with TSWV as indicated by a lack of systemic symptoms and little or no systemic accumulation of virus as determined by double antibody sandwich enzyme-liked immunosorbent assay. These results further extend the applicability of coat protein-mediated resistance, as previously demonstrated for a number of simple plant viruses composed of a positive-sense RNA genome encapsidated with a single species of coat protein, to a membrane-encapsidated, multi-component, negative-sense RNA virus.

Transgenic Nicotiana debneyii expressing viral coat protein are resistant to potato virus S infection

The coat protein gene from potato virus S (PVS) was introduced into Nicotiana debneyii by leaf disc transformation using Agrobacterium tumefaciens. Transgenic plants expressing the viral coat protein were highly resistant to subsequent infection by the ME strain of PVS as indicated by an absence of symptom development and a lack of accumulation of virus in both the inoculated and upper leaves. As in reported experiments with plants expressing potato virus X coat protein, plants expressing PVS coat protein were also protected from inoculation with PVS RNA. These results provide further evidence that coat protein-mediated protection for these two groups of viruses, which share similar genome organizations, may involve inhibition of some early event in infection other than or in addition to virus uncoating.

Organization and interviral homologies of the 3'-terminal portion of potato virus S RNA

The sequence of 3553 nucleotides corresponding to the 3'-terminal region of potato virus S (PVS) has been determined from cloned cDNA. The sequence obtained contains six open reading frames (ORFs) encoding proteins of Mr 10,734, Mr 32,515, Mr 7,222, Mr 11,802, Mr 25,092 and at least Mr 41,052. The sequence of the 33K ORF has been confirmed to be that of the viral coat protein gene. The nucleotide sequence of this ORF was obtained from plasmids which were isolated by colony hybridization with a specific monoclonal antibody to PVS, and the expression of coat protein fusion products was verified by Western blots of bacterial cell lystates. The deduced amino acid sequence of a 70 amino acid portion from the central region of the PVS coat protein was 59% identical to the analogous region of potato virus X. In addition, the 7K, 12K and 25K ORFs displayed significant sequence homology with the similarly sized ORFs from a number of potexviruses. The partial 41K ORF product was homologous with the C-terminal portion of the viral replicase proteins of potato virus X and white clover mosaic virus.

Subacute sclerosing panencephalitis (SSPE) in southern Africa. Recent additions to the SSPE Registry

Subacute sclerosing panencephalitis can no longer be regarded as a rare disease in all parts of southern Africa. Information derived from a third postal survey added to that from our own experience in Cape Town has brought to light 116 cases; 61 of the patients came from the Cape Province, 40 from the Transvaal and the remaining 15 from the other regions. This unequal distribution and the high prevalence in the Coloured community are important factors in any attempt to understand the epidemiology and the pathogenesis of this serious complication of measles.