Encapsulation of recombinant <Emphasis Type="Italic">E. coli</Emphasis> expressing cyclopentanone monooxygenase in polyelectrolyte complex capsules for Baeyer–Villiger biooxidation of 8-oxabicyclo[3.2.1]oct-6-en-3-one

Recombinant Escherichia coli cells, over-expressing cyclopentanone monooxygenase activity, were immobilized in polyelectrolyte complex capsules, made of sodium alginate, cellulose sulfate, poly(methylene-co-guanidine), CaCl₂ and NaCl. More than 90% of the cell viability was preserved during the encapsulation process. Moreover, the initial enzyme activity was fully maintained within encapsulated cells while it halved in free cells. Both encapsulated and free cells reached the end point of the Baeyer–Villiger biooxidation of 8-oxabicyclo[3.2.1]oct-6-en-3-one to 4,9-dioxabicyclo[4.2.1]non-7-en-3-one at the same time (48 h). Similarly, the enantiomeric excess above 94% was identical for encapsulated and free cells.     

Sex and size related differences in the dry season feeding patterns of elephants in Chobe National Park, Botswana

Differences in feeding patterns of the African elephant were examined by sex and age during the dry season in a dystrophic savanna-woodland ecosystem in northern Botswana. Adult males had the least diverse diet in terms of woody plant species, but they consumed more plant parts than family units. The diameter of stems of food plants broken or bitten off was also greater for adult males than for females and subadult males. Adult males spent more time foraging on each woody plant than did females. The number of woody plant species and individuals present were higher at feeding sites of family units than at feeding sites of adult males, indicating that family units positioned themselves at feeding sites with higher species diversity than those of males. We argue that the most likely explanation for these differences is related to the pronounced sexual size dimorphism exhibited by elephants, resulting in sex differences in browsing patterns due to the allometric relationships that govern the tolerance of herbivores for variation in diet quality. From our results this Body Size Hypothesis is accepted rather than the alternative Scramble Competition Hypothesis, which predicts that adult male elephants consume lower quality browse because they are displaced from preferred browse as an outcome of scramble competition with adult females and their offspring. If the feeding patterns of adult male elephants were affected by intersexual scramble competition, we would expect adult males to browse at a higher level in the canopy than the smaller-bodied females and their offspring. No evidence was found for this, although adult females were found to browse at a higher level in the canopy when feeding in close proximity to subadults and juveniles than when feeding alone. Sex differences in elephant browsing patterns are, we propose, of relevance to understanding and managing elephant impacts on African woodlands.     

Wine biotechnology in South Africa: towards a systems approach to wine science

The wine industry in South Africa is over three centuries old and over the last decade has reemerged as a significant competitor in world wine markets. The Institute for Wine Biotechnology (IWBT) was established in partnership with the Department of Viticulture and Oenology at Stellenbosch University to foster basic fundamental research in the wine sciences leading to applications in the broader wine and grapevine industries. This review focuses on the different research programmes of the Institute (grapevine, yeast and bacteria biotechnology programmes, and chemical-analytical research), commercialisation activities (SunBio) and new initiatives to integrate the various research disciplines. An important focus of future research is the Wine Science Research Niche Area programme, which connects the different research thrusts of the IWBT and of several research partners in viticulture, oenology, food science and chemistry. This 'Functional Wine-omics' programme uses a systems biology approach to wine-related organisms. The data generated within the programme will be integrated with other data sets from viticulture, oenology, analytical chemistry and the sensory sciences through chemometrics and other statistical tools. The aim of the programme is to model aspects of the wine making process, from the vineyard to the finished product.     

Genetic and biochemical evidence for involvement of HOTHEAD in the biosynthesis of long-chain α-,ω-dicarboxylic fatty acids and formation of extracellular matrix

In plants, extracellular matrix polymers built from polysaccharides and cuticular lipids have structural and protective functions. The cuticle is found to be ten times thinner in Arabidopsis thaliana (L.) Heynh than in many other plants, and there is evidence that it is unusual in having a high content of α-,ω-dicarboxylic fatty acids (FAs) in its polyesters. We designated the new organ fusion mutant hth-12 after it appeared to be allelic to adhesion of calyx edges (ace) and hothead (hth), upon molecular cloning of the gene by transposon tagging. This mutant is deficient in its ability to oxidize long-chain ω-hydroxy FAs to ω-oxo FAs, which results in leaf polyesters in decreased α-,ω-dicarboxylic FAs and increased ω-hydroxy FAs. These chemical phenotypes lead to disorder of the cuticle membrane structure in hth-12. ACE/HTH is a single-domain protein showing sequence similarity to long-chain FA ω-alcohol dehydrogenases from Candida species, and we hypothesize that it may catalyze the next step after cytochrome P450 FA ω-hydroxylases in the ω-oxidation pathway. We show that ACE/HTH is specifically expressed in epidermal cells. It appears very likely therefore that the changes in the amount of α-,ω-dicarboxylic FAs in hth-12 reflect the different composition of cuticular polyesters. The ACE/HTH gene is also expressed in root epidermal cells which do not form a polyester membrane on the exterior surface, thereby making it possible that the end products of the pathway, α-,ω-dicarboxylic FAs, are generally required for the cross-linking that ensures the integrity of the outer epidermal cell wall.     

Physicomechanical Characterization and Optimization of EDTA–mPEG and Avicel®–EDTA–mPEG In Situ Melt Dispersion Mini-Pellets

The purpose of this study was to develop a physicomechanically customizable oral metal chelatory in situ hot melt dispersion mini-pellet entity which could be utilized within a binary drug delivery system. Avicel^® RC/CL type R-591 was included within the in situ hot melt dispersion mini-pellet formulations to determine the physicomechanical effect this compound would have on the mini-pellet formulations. The physicomechanical properties of the hot melt in situ mini-pellet formulations were mathematically fitting to regression curves. Physicomechanical adjustment of the in situ hot melt dispersion mini-pellet formulations could be mathematically predicted with the derived regression curve equations. The addition of Avicel^® RC/CL type R-591 increased the physicomechanical properties such as matrix hardness and increased total disintegration of the in situ hot melt dispersion mini-pellet formulations. The utilization of a physicomechanically customizable oral metal chelatory in situ hot melt dispersion mini-pellet entity within a binary drug delivery system would to achieve a synergistically enhance the activity of a drug-carrying entity or a permeation enhancing entity within a single drug delivery unit. The experimental results indicated that weights of the pellets that achieved optimal hardness ranged between 35 and 45 mg. The melt–dispersion formulations disintegrated within shorter time periods and maintained higher ethylenediaminetetraacetic acid (EDTA) concentrations whereas melt–dispersion formulations which included Avicel^® had superior physicomechanical properties. Disintegration times ranged between 1,000 s for melt–dispersions containing EDTA and methyloxy polyethylene glycol 2000 (mPEG) only, to >6,000 s for melt–dispersions comprising EDTA, mPEG, and Avicel^®.     

Neural Control of Enhanced Filtering Demands in a Combined Flanker and Garner Conflict Task

Several studies demonstrated that visual filtering mechanisms might underlie both conflict resolution of the Flanker conflict and the control of the Garner effect. However, it remains unclear whether the mechanisms involved in the processing of both effects depend on similar filter mechanisms, such that especially the Garner effect is able to modulate filtering needs in the Flanker conflict. In the present experiment twenty-four subjects participated in a combined Garner and Flanker task during two runs of functional magnetic resonance imaging (fMRI) recordings. Behavioral data showed a significant Flanker but no Garner effect. A run-wise analysis, however, revealed a Flanker effect in the Garner filtering condition in the first experimental run, while we found a Flanker effect in the Garner baseline condition in the second experimental run. The fMRI data revealed a fronto-parietal network involved in the processing of both types of effects. Flanker interference was associated with activity in the inferior frontal gyrus, the anterior cingulate cortex, the precuneus as well as the inferior (IPL) and superior parietal lobule (SPL). Garner interference was associated with activation in middle frontal and middle temporal gyrus, the lingual gyrus as well as the IPL and SPL. Interaction analyses between the Garner and the Flanker effect additionally revealed differences between the two experimental runs. In the first experimental run, activity specifically related to the interaction of effects was found in frontal and parietal regions, while in the second run we found activity in the hippocampus, the parahippocampal cortex and the basal ganglia. This shift in activity for the interaction effects might be associated with a task-related learning process to control filtering demands. Especially perceptual learning mechanisms might play a crucial role in the present Flanker and Garner task design and, therefore, increased performance in the second experimental run could be the reason for the lack of behavioral Garner interference on the level of the whole experiment.     

The occurrence of malolactic fermentation in brandy base wine and its influence on brandy quality

AIMS: In this study we determined the extent to which lactic acid bacteria (LAB) occurred in brandy base wines, their ability to catalyse the malolactic fermentation (MLF) and the effect of MLF on the quality of the base wine and the brandy distillate. METHODS AND RESULTS: Lactic acid bacteria were isolated and enumerated from grape juice, experimental and commercially produced brandy base wines. Spontaneous MLF occurred in approximately 50% of the commercial base wines. The occurrence of MLF had an influence on the quality of the base wines and the resulting distillates. In samples where MLF occurred there was a loss of fruitiness and in the intensity of aroma. Volatile compounds like iso-amyl acetate, ethyl acetate, ethyl caproate, 2-phenethyl acetate and hexyl acetate decreased in samples having undergone MLF, while ethyl lactate, acetic acid and diethyl succinate increased in the same samples. CONCLUSIONS: Spontaneous malolactic fermentation does occur in commercial brandy base wines and it has an influence on base wine and brandy quality. SIGNIFICANCE AND IMPACT OF THE STUDY: This study showed that MLF influences the quality of the base wine and the resulting distillate and with this in mind commercial base wine producers should be able to produce brandy of higher quality.     

Systematic Phenotyping of a Large-Scale Candida glabrata Deletion Collection Reveals Novel Antifungal Tolerance Genes

The opportunistic fungal pathogen Candida glabrata is a frequent cause of candidiasis, causing infections ranging from superficial to life-threatening disseminated disease. The inherent tolerance of C. glabrata to azole drugs makes this pathogen a serious clinical threat. To identify novel genes implicated in antifungal drug tolerance, we have constructed a large-scale C. glabrata deletion library consisting of 619 unique, individually bar-coded mutant strains, each lacking one specific gene, all together representing almost 12% of the genome. Functional analysis of this library in a series of phenotypic and fitness assays identified numerous genes required for growth of C. glabrata under normal or specific stress conditions, as well as a number of novel genes involved in tolerance to clinically important antifungal drugs such as azoles and echinocandins. We identified 38 deletion strains displaying strongly increased susceptibility to caspofungin, 28 of which encoding proteins that have not previously been linked to echinocandin tolerance. Our results demonstrate the potential of the C. glabrata mutant collection as a valuable resource in functional genomics studies of this important fungal pathogen of humans, and to facilitate the identification of putative novel antifungal drug target and virulence genes.     

Asymmetric cytokinin signaling opposes gravitropism in roots

Plants depend on gravity to provide the constant landmark for downward root growth and upward shoot growth. The phytohormone auxin and its cell‐to‐cell transport machinery are central determinants ensuring gravitropic growth. Statolith sedimentation toward gravity is sensed in specialized cells. This positional cue is translated into the polar distribution of PIN auxin efflux carriers at the plasma membrane, leading to asymmetric auxin distribution and consequently, differential growth and organ bending. While we have started to understand the general principles of how primary organs execute gravitropism, we currently lack basic understanding of how lateral plant organs can defy gravitropic responses. Here we briefly review the establishment of the oblique gravitropic set point angle in lateral roots and particularly discuss the emerging role of asymmetric cytokinin signaling as a central anti‐gravitropic signal. Differential cytokinin signaling is co‐opted in gravitropic lateral and hydrotropic primary roots to counterbalance gravitropic root growth.