Exceptional hexose-fermenting ability of the xylitol-producing yeast Candida guilliermondii FTI 20037.

The yeast Candida guilliermondii FTI 20037 is well-known for its ability to produce xylitol from xylose. Recently, this strain was found to produce greater than 5% (w/v) ethanol from glucose. This level of ethanol is typically not exceeded by wild-type strains of other native pentose-fermenting yeasts. This prompted the current study to examine the ability of C. guilliermondii FTI 20037 to utilize and ferment high concentrations of each of the hexoses commonly found in lignocellulosic hydrolysates. In defined media, FTI 20037 fermented 14.4%-25.9% (w/v) of glucose, mannose or galactose individually to ethanol in concentrations ranging from 6% to 9.3% (w/v). Fermentation was completed within 36 h (for glucose) to 100 h (for galactose). In 25.9% (w/v) glucose, FTI 20037 produced 9.3% (w/v) ethanol within 40 h. FTI 20037 produced xylitol exclusively when xylose was given as the sole carbon source. The strain utilized arabinose poorly. Under the same fermentation conditions, an industrial Saccharomyces cerevisiae strain produced slightly higher levels of ethanol [9.9% (w/v)] from 25.0% (w/v) glucose. Another pentose-fermenting yeast Pachysolen tannophilus also fermented high concentrations of glucose and mannose to produce relatively high peak ethanol concentrations; however, this yeast required considerably longer to completely consume these hexoses. The ability of FTI 20037 to produce high level of ethanol rapidly from glucose is remarkable. To our knowledge, this is the first known instance of a non-modified native xylose-fermenting yeast strain able to produce such high levels of ethanol from glucose as rapidly as S. cerevisiae in a defined medium.

Toward the total synthesis of variecolin.

[reaction: see text] An annulative approach toward the total synthesis of the sesterterpenoid variecolin (1) is presented. Synthesis of the key hemiketal, containing the core ABC ring skeleton, has been achieved on a model system by an expeditious route utilizing samarium(II) iodide. Furthermore, enantioselective syntheses of component fragments for the total synthesis have been developed.

Interrater reliability of the Technology Team Assessment Process.

OBJECTIVE: This study examined the interrater reliability of the Technology Team Assessment Process (TTAP). METHOD: Students ages 9 to 12 years who have learning disabilities received a TTAP assessment, which was videotaped. Five independent raters trained in the assessment process observed the videotapes and rated each student with the TTAP recording forms. Additionally, each rater made specific assistive technology recommendations on the basis of his or her evaluation. RESULTS: Intraclass correlation coefficients revealed that only one of four sections of the TTAP investigated had low to moderate interrater reliability for the students evaluated CONCLUSION: The results of this study suggest that the TTAP, in its present form, cannot be used with confidence to assess students with learning disabilities and requires more extensive development and testing.

Transitions: From school to adult life.

Occupational therapy has a unique and valuable contribution to make to the transition of students with disabilities from school to productive adult life. This contribution includes utilization of an ecological approach that considers student performance of essential occupations in a range of natural environments including on-the-job. Legislative background, the specific role of occupational therapy on the transition team, and challenges related to implementation of effective transition services, are presented in this article.

Inhibition of Cyanogenesis by tannins.

During isolation of two biosynthetic types of cyanogenic glycosides fromCarica papaya, weak cyanide tests were obtained from initial fractions. Upon final purification, strongly positive cyanide tests were obtained. Pretreatment of extracts to remove polyphenolics alleviated inhibition of cyanogenesis, which led us to suspect that tannins were inhibitory agents. Qualitative and quantitative measures of inhibition were made using standard cyanogenic glycosides and polyphenolics. Cyanogenesis was inhibited quantitatively when condensed tannins (quebracho, wattle, and chestnut), or hydrolyzable tannin (tannic acid) were added. When tannins were precipitated from the reaction mixture, cyanide tests proceeded optimally. These results stress the need to interpret negative cyanide tests with care and indicate possible ecological synergisms between plant defensive chemicals.

Gynocardin from passiflora.

Gynocardin has been isolated and identified for the first time from a species of PASSIFLORA. This compound is typical of the FLACOURTIACEAE, and its presence in the PASSIFLORACEAE underscores the close relationship of the two families.

Gynocardin and tetraphyllin B from Carpotroche brasiliensis.

Gynocardin and Tetraphyllin B were isolated from the seeds and pericarp of Carpotroche brasiliensis (Raddi) Endl. (Flacourtiaceae). The cyanogenic glycosides occur in an approximately equimolar mixture in the seeds and in the pericarp. Their structures were confirmed by (1)H-NMR.

Tetraphyllin B from Turnera diffusa.

Tetraphyllin B has been isolated from the tropical American species Turnera diffusa Willd. The structure was established by NMR and MS.