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• Combinations of P and water management options were tested in P deficient lowlands. • Root development of rice can be modified by specific P- but mainly by water management. • Under P limitation, reduced irrigation enhances rice development, P uptake, and yield. • Micro-dose P placements can reverse P depletion in deficient lowlands. • For small P placement rates, interactions with water management should be considered. Lowland rice production in sub-Saharan Africa (SSA) is often limited by water supply and low phosphorus (P) availability and efforts are needed towards more efficient management of both resources. Field and pot experiments were set up to evaluate combinations of water saving technologies and micro-dose P placement methods (i.e. the localized application of a small P dose to a sub-surface area, often combined with seeds into the planting hole) with due attention to treatment effects on root architecture. A two-year field experiment was set up in a lowland rice field in Tanzania with factorial combinations of different levels of water supply (field capacity, alternating wetting drying, permanent flooding) and P application (no P; 3.45 and 6.90 kg ha−1 placement versus 25 kg ha−1 broadcast), thereby testing residual effects in year 2. A trial in pots (10.5 L) was additionally performed with equivalent treatments and allowing measurements of soil solution composition, apparent fertilizer efficiency, and root density versus depth. Rice grain yields ranged 0–5 ton ha−1 and mainly responded to P application. The P placement at the lowest P rate resulted in higher grain yield at field capacity (2.0–2.5 ton ha−1) than in flooded rice (1.2–1.6 ton ha−1), whereas these differences were absent at higher P rates. Lower water supply at field capacity enhanced root growth and rooting depth, decreased nodal root thickness and enhanced root P uptake efficiency compared to flooded condition. Modelling P diffusion outwards the granules showed more restricted P diffusion under reduced water supply and, therefore, less P immobilization in the soil under field capacity. These differences between water treatments were more pronounced at lower than at higher P supply. This study shows that both root responses and P diffusion outwards placed granules explain rice development and yields under micro-dose P placement and water saving technologies. P placement can contribute to intensify rice production while countering soil P decline in P deficient lowlands when resources are limited. [ABSTRACT FROM AUTHOR]

Synthesis of medium-chain sophorolipids by Candida bombicola is a challenging objective. One of the difficulties is that the obtained sophorolipids always represent a mixture of medium-chain and native de novo formed or long-chain sophorolipids. The fatty acid moiety of de novo sophorolipids is derived from the de novo synthesis of fatty acids. Fatty acid synthesis can be blocked by the antifungal agent cerulenin, an inhibitor if the fatty acid synthase (FAS) complex acting on the β-ketoacyl thioester synthetase reaction. The toxic effect of cerulenin on C. bombicola was evaluated and 20 mg/ml was added in the stationary growth phase. No de novo formed sophorolipids were observed when the cells were cultured on merely glucose. Also when the hydrophilic substrate, 1,12-dodedanediol, was added, no de novo formed sophorolipids were detected, leading to a reduced complexity of the sophorolipid mixture. [ABSTRACT FROM AUTHOR]

E. coli is still one of the most commonly used hosts for protein production. However, when it is grown with excess glucose, acetate accumulation occurs. Elevated acetate concentrations have an inhibitory effect on growth rate and recombinant protein yield, and thus elimination of acetate formation is an important aim towards industrial production of recombinant proteins. Here we examine if over-expression of citrate synthase ( gltA) or phosphoenolpyruvate carboxylase ( ppc) can eliminate acetate production. Knock-out as well as over-expression mutants were constructed and characterized. Knocking out ppc or gltA decreased the maximum cell density by 14% and increased the acetate excretion by 7%, respectively decreased it by 10%. Over-expression of ppc or gltA increased the maximum cell dry weight by 91% and 23%, respectively. No acetate excretion was detected at these increased cell densities (35 and 23 g/l, respectively). [ABSTRACT FROM AUTHOR]

Carbohydrates on epithelial cell surfaces play an important role as attachment sites for different microorganisms like bacteria, viruses and protozoa. To obtain more information about the distribution of carbohydrates on the luminal surface along the intestine, lectin histochemical studies on different gut segments of chicks of different age groups were carried out using a panel of 13 lectins with specificities for Man, Glc, Gal, GalNAc, GlcNAc or GlcNAc oligosaccharides and Sia. Furthermore, we tried to find out whether previously reported specificities of certain lectins for M cells (membranous or multifold cells) in the bursa of Fabricius (BF) can be observed also on M cells of the intestine. As a result we were able to demonstrate binding of all lectins employed in these studies in all investigated gut segments. In some cases, the application of the same lectin led to varying staining intensities of the same histological structures in different age-groups (e.g. staining of the brush border with WGA, LEA, MAA or Conarva) or different gut segments (e.g. staining of goblet cells with CMA II, LEA and MPA). Hence, terminal carbohydrate residues of glycoconjugates on the intestinal epithelium vary depending on age and organ site. As glycoconjugates can act as attachment sites for microorganisms, these differences in the distribution of sugar residues may be one explanation for the site-specificity of certain pathogens. Furthermore, the binding of lectins to the follicle-associated epithelium (FAE) of the BF differs from that to the FAE of the intestine again stressing the site specificity of lectin binding. Thus, up to now no universal M-cell marker along the chicken intestine exists. [ABSTRACT FROM AUTHOR]

Apparent degradation of the RF characteristics of silicon MOSFETs was observed under normal operating conditions. We show that it was not caused by intrinsic device degradation but originated from a degradation of the contact resistance between probe and bonding pad. Guidelines, not limited to MOSFETs only, are given that enable accurate S-parameter measurements for RF modelling and reliability assessment. © 2001 John Wiley & Sons, Inc. Int J RF and Microwave CAE 11: 114–120, 2001. [ABSTRACT FROM AUTHOR]

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Vinegar production has a long history worldwide and has evolved over centuries from an art and handicraft into a controlled fermentation process nowadays. Many medieval manuscripts (13th-15th century) with medicinal, alchemy-related or kitchen recipes report on the trade and practice of vinegar production. In Europe, till first half of the 16th century, vinegar was mainly made from wine (as source of ethanol) in the households. Around 1600, poor grape harvests and colder climate conditions led to a switch to brew vinegar rather from mead, apple cider and mainly from beer; also production moved from the households to true vinegar breweries, usually located in the cities. This was the established trade situation till the 19th century, but then it changed drastically, due to scientific and technological developments. The invention of the continuous distillation column and the availability of cheap raw materials (beet sugar, molasses, potatoes, maize, ...) for producing distilled alcohol led the yeast, genever and spiritus factories to produce also alcohol vinegar. Famous Dutch (Clusius, Boerhaave), French (Pasteur, Lavoisier) and German (Kutzing, Liebig) scientists resolved in the meantime the secrets of vinegar fermentation. Based on Louis Pasteur's findings since 1858, a broth containing 10-14% alcohol, ammonium salts and autolysed yeast, could be fermented aerobically by acetic acid bacteria into vinegar in high yield. This fermentation alcohol based vinegar process is now worldwide applied. Fruit vinegars dominate in Europe, while cereal vinegars are typical for Asia. Specialty vinegar brands are on the rise again. In addition to Japanese microbiologists (Asai, Yamada, ...), also microbiologists from Belgian universities (Frateur from Louvain; De Ley from Ghent) contributed in the 20th century much to the taxonomy, physiology and genetics of the acetic acid bacteria. Vinegar production is indeed a nice example of industrial biotechnology avant la lettre, evolving from small-scale surface culture in barrels (Orleans process) via immobilized cell culture (Boerhaave/Schuzenbach/Frings process) or solid state to currently large-scale (100 m³) submerged (acetator) fermentation processes. In most cases, a seed vinegar (undefined mixed) - starter culture is essential to obtain a desired vinegar brand up till today!. [ABSTRACT FROM AUTHOR]