Environmental responses and productivity of the CAM plant, Agave tequilana

Agave tequilana (Weber), whose stem is commercially harvested for the production of the distilled alcoholic beverage tequila, exhibited Crassulacean acid metabolism (CAM), as do other agaves. About 87% of net CO2 uptake occurred at night and was accompanied by an increase in tissue acidity. Such nocturnal acid accumulation was maximal for day/night air temperatures of 30�C/15�C, approximately the mean annual values at the field site in Tequila, Jalisco, Mexico. Nocturnal acid accumulation increased with the total daily photosynthetically active radiation (PAR) incident on the leaves, reaching 90% of maximum at 22 mol PAR m-2. Drought reduced nocturnal acid accumulation by 50% after 7 days and by 90% after 30 days. For the 1-year study period, 93% of the annual rainfall of 1082 mm occurred from June to September, leading to a water index (nocturnal acid accumulation relative to that under wet conditions) averaging 0.95 for June through November. For this 6-month period, the temperature index averaged 0.89 and the PAR index averaged 0.44, indicating that PAR was then the main environmental factor limiting nocturnal acid accumulation by A. tequilana. The product of these three indices was termed the environmental productivity index (EPI); when EPI was >0.2 generally 4 or more leaves unfolded monthly from the central spike of the rosette, but when EPI was <0.1 usually less than half as many leaves unfolded. Based on the plant fraction made up of leaves (55-60% by dry weight) and the leaf dry weight as a function of leaf length, productivity could be determined per unit ground area. For plants initially 1-, 3-, and 6-years-old, the dry weight productivity was 2.49, 2.24, and 2.11 kg m-2y-1, respectively. This is higher than for any other CAM plant so far reported and is in the range of 2-3 kg m-2y-1 found for many C3 and C4 crops. � 1987

Isolierung und Absicherung grundwasserkontaminierender Schadstoffquellen im Untergrund durch Umschliessung mittels Dichtwaenden und Injektionssohlen Abschlussbericht

SIGLECopy held by FIZ Karlsruhe; available from UB/TIB Hannover / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Pelletization of seeds of Raphanus sativus L. cv. Redondo Gigante with graphite for germination under water stress conditions

The effect of water stress on germination of radish seeds is dependent on the presence of light. The effect of pelletization of radish seeds with powdered graphite on the tolerance to water stress under light was analysed. White light and far-red lights were filtered by graphite increasing slightly the tolerance of pelleted seeds to water stress of -0.77MPa. Although red light also inhibited seed germination the graphite had no effect. We propose the pelletization of seeds of Raphanus sativus, at least in cv redondo gigante with graphite as a pratice before planting to increase the tolerance to water stress.<br>O efeito do estresse hídrico é dependente da presença de luz em sementes de rabanete. O efeito da peletização com grafite em pó foi analisado. Luz branca e vermelho-extremo são filtradas pelo grafite aumentando parcialmente a tolerância ao estresse hídrico de -0,77MPa em sementes peletizadas. Embora a luz vermelha também iniba a germinação em condições de estresse a peletização não teve efeito. Nós propomos a peletização de sementes de Raphanus saivus L. cv. redondo gigante como uma prática antes do plantio para aumentar a tolerância ao estresse hídrico

Assessment of CFTR function in homozygous R117H-7T subjects

Background: R117H is a frequent missense mutation included in most CFTR mutation panels. However knowledge about the residual function of R117H-CFTR channels in cystic fibrosis-affected organs, e.g. airways, intestines and sweat glands is presently lacking. Methods: We evaluated clinical CF symptoms and assessed CFTR function by sweat tests, nasal potential difference and intestinal current measurements in 2 homozygous R117H individuals (7T variant). Results: The CFTR activity in airways and intestine was within the normal range. However both individuals presented with a borderline sweat test and the male patient was infertile. Conclusions: The lack of impact of the R117H mutation on chloride secretion in intestine and nose contrasts with the similar to 80% loss of CFTR activity reported in patch clamp studies. Apparently CFTR activity is not rate-limiting for chloride secretion in both tissues at levels >20% of normal, or compensatory factors may operate that are absent in heterologous host cells in vitro. (C) 2011 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved

Evidence for associations between the purinergic receptor P2X₇ (P2RX7) and toxoplasmosis

Congenital Toxoplasma gondii infection can result in intracranial calcification, hydrocephalus and retinochoroiditis. Acquired infection is commonly associated with ocular disease. Pathology is characterized by strong proinflammatory responses. Ligation of ATP by purinergic receptor P2X7, encoded by P2RX7, stimulates proinflammatory cytokines and can lead directly to killing of intracellular pathogens. To determine whether P2X7 has a role in susceptibility to congenital toxoplasmosis, we examined polymorphisms at P2RX7 in 149 child/parent trios from North America. We found association (FBAT Z-scores ±2.429; P=0.015) between the derived C(+)G(−) allele (f=0.68; OR=2.06; 95% CI: 1.14–3.75) at single-nucleotide polymorphism (SNP) rs1718119 (1068T>C; Thr-348-Ala), and a second synonymous variant rs1621388 in linkage disequilibrium with it, and clinical signs of disease per se. Analysis of clinical subgroups showed no association with hydrocephalus, with effect sizes for associations with retinal disease and brain calcifications enhanced (OR=3.0–4.25; 0.004<P<0.009) when hydrocephalus was removed from the analysis. Association with toxoplasmic retinochoroiditis was replicated (FBAT Z-scores ±3.089; P=0.002) in a small family-based study (60 families; 68 affected offspring) of acquired infection in Brazil, where the ancestral T(+) allele (f=0.296) at SNP rs1718119 was strongly protective (OR=0.27; 95% CI: 0.09–0.80)