Identification and characterization of a solute carrier, CIA8, involved in inorganic carbon acclimation in Chlamydomonas reinhardtii

© The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology. The supply of inorganic carbon (Ci) at the site of fixation by Rubisco is a key parameter for efficient CO2 fixation in aquatic organisms including the green alga, Chlamydomonas reinhardtii. Chlamydomonas reinhardtii cells, when grown on limiting CO2, have a CO2-concentrating mechanism (CCM) that functions to concentrate CO2 at the site of Rubisco. Proteins thought to be involved in inorganic carbon uptake have been identified and localized to the plasma membrane or chloroplast envelope. However, current CCM models suggest that additional molecular components are involved in Ci uptake. In this study, the gene Cia8 was identified in an insertional mutagenesis screen and characterized. The protein encoded by Cia8 belongs to the sodium bile acid symporter subfamily. Transcript levels for this gene were significantly up-regulated when the cells were grown on low CO2. The cia8 mutant exhibited reduced growth and reduced affinity for Ci when grown in limiting CO2 conditions. Prediction programs localize this protein to the chloroplast. Ci uptake and the photosynthetic rate, particularly at high external pH, were reduced in the mutant. The results are consistent with the model that CIA8 is involved in Ci uptake in C. reinhardtii

Health-related quality-of-life results from the randomised phase II TAVAREC trial on temozolomide with or without bevacizumab in 1p/19q intact first-recurrence World Health Organization grade 2 and 3 glioma (European Organization for Research and Treatment of Cancer 26091)

Background: In an international randomised controlled phase II study of temozolomide (TMZ) versus TMZ in combination with bevacizumab (BEV) in locally diagnosed non-1p/19q co-deleted World Health Organization grade 2 or 3 gliomas with a first and contrast-enhancing recurrence after initial radiotherapy, and overall survival at 12 months was not significantly different (61% in the TMZ arm and 55% in the TMZ + BEV arm). Objectives: Health-related quality of life (HRQoL) was a key secondary end-point in this trial, and the main objective of this study was to determine the impact of the addition of BEV to TMZ on HRQoL. Methods: HRQoL was assessed using the European Organization for Research and Treatment of Cancer QLQ-C30 (version 3) and QLQ-BN20 at baseline, and then every 12 weeks until disease progression. The pre-selected primary HRQoL end-point was the QLQ-C30 global health scale, with self-perceived cognitive functioning and pain selected as secondary HRQoL issues. Analysis was undertaken using linear mixed modelling and complemented with sensitivity analyses using summary statistics. A difference was considered clinically relevant with ≥10 points difference on a 100-point scale. Results: Baseline compliance was high at 94% and remained above 60% until 72 weeks, limiting the analysis to 60 weeks. Compliance was similar in both arms. We found no statistically significant or clinically significant differences between the primary HRQoL end-point in both treatment arms (p = 0.2642). The sensitivity analyses confirmed this finding. The overall test for post-baseline differences between the two treatment arms also showed no statistically or clinically significant differences regarding the selected secondary end-point scales. Interpretation: The addition of BEV to TMZ in this patient group neither improves nor negatively impacts HRQoL.</p

Identification and characterization of a solute carrier, CIA8,involved in inorganic carbon acclimation in Chlamydomonas reinhardtii

The supply of inorganic carbon (Ci) at the site of fixation by Rubisco is a key parameter for efficient CO2 fixation in aquatic organisms including the green alga, Chlamydomonas reinhardtii. Chlamydomonas reinhardtii cells, when grown on limiting CO2, have a CO2-concentrating mechanism (CCM) that functions to concentrate CO2 at the site of Rubisco. Proteins thought to be involved in inorganic carbon uptake have been identified and localized to the plasma membrane or chloroplast envelope. However, current CCM models suggest that additional molecular components are involved in Ci uptake. In this study, the gene Cia8 was identified in an insertional mutagenesis screen and characterized. The protein encoded by Cia8 belongs to the sodium bile acid symporter subfamily. Transcript levels for this gene were significantly up-regulated when the cells were grown on low CO2. The cia8 mutant exhibited reduced growth and reduced affinity for Ci when grown in limiting CO2 conditions. Prediction programs localize this protein to the chloroplast. Ci uptake and the photosynthetic rate, particularly at high external pH, were reduced in the mutant. The results are consistent with the model that CIA8 is involved in Ci uptake in C. reinhardtii

PHYSIOLOGICAL RESPONSES TO WATER DEFICIT BY SORGHUM BICOLOR GENOTYPES VARYING IN EXPRESSION OF THE LIMITED TRANSPIRATION TRAIT

The ability by land plants to partially close their stomata in response to high vapor pressure deficit, called the limited transpiration trait, is a rare phenomenon in crop plants. The characteristic has been demonstrated in several crop species including Sorghum bicolor. The molecular and physiological basis for the limited transpiration trait is however, not clear. This study was conducted to determine the physiological attributes associated with the limited transpiration trait in three sorghum genotypes SC1345, SC35 and Macia. Plants of these three sorghum genotypes were established in a greenhouse and subjected to water deficit stress. Chlorophyll fluorescence and relative water content were assessed after exposing plants to water deficit. The two genotypes with an ability to express the limited transpiration trait (SC35 and Macia) were able to maintain a higher water status while genotype SC1345, which does not have a transpiration breakpoint, had a significantly lower water status compared to controls. In addition, an interesting pattern for chlorophyll fluorescence was observed in the genotypes expressing the limited transpiration trait. The results confirm that the limited transpiration trait helps to maintain plant water status, and also suggest that chlorophyll fluorescence could be used to screen for the trait

A facilitated process towards finding options for improved livestock production in the communal areas of Sterkspruit in the Eastern Cape province, South Africa

A participatory multi-stakeholder process of finding options for improving livestock production in the severely degraded communal grazing area of Sterkspruit in South Africa was conducted. Interviews were conducted with individual livestock keepers from two sites to gather data on their demographic characteristics, livestock holdings, and main sources of income. Interviews and focus workshops with various stakeholders and the livestock keepers were conducted on what they perceived to be options for improving livestock production. Livestock keepers comprised less than 20% of the entire population in both villages, consisting of individuals about 60 years of age. About 60% kept less than eight cattle. Regardless of herd size, about 40% relied on old-age and welfare grants rather than livestock for income. Livestock keepers identified options promoting survival of livestock, such as improved veterinary services and winter feeding as a priority. In contrast, other stakeholders, including representatives of government, municipalities, farmers unions and commodity associations, identified options for reducing livestock numbers, such as marketing and removal of large stock owners to private land, as a priority for reducing degradation due to overstocking. Due to this difference in goals and aspirations, no common set of priorities could be agreed upon. Keywords: degradation; livelihoods; livestock keepers; multi-stakeholder; participatoryAfrican Journal of Range & Forage Science 2008, 25(2): 63–6