Model of ammonia volatilization from calcareous soils

A quantitative model of ammonia volatilization from the calcareous soil uppermost 1-cm layer was developed and tested. The model accounts for the following processes: ammonium-ammonia equilibration in the soil solution, cation exchange between calcium and ammonium which results in ammonium distribution between soil liquid and solid phases, nitrification of dissolved ammonium, distribution of ammonia between liquid and gaseous phases and diffusion of gaseous ammonia in the soil air. The combined effect of various characteristics such as soil pH, cation exchange capacity, water capacity and nitrification rate on ammonia losses from various soil types have been studied. The model was validated against experimental results of ammonia losses from different soils for its use as a predicting tool. The model shows that most of ammonia losses can be explained by the interactive effect of high soil pH and low cation exchange capacity. Computations show increased ammonia volatilization with decreasing soil water capacity. Increasing fertilizer application rate has a small effect on percentage of ammonia losses. Increased nitrification rate and shorter “lag” period of nitrification reduce ammonia losses considerably. Good agreement was obtained between model calculations and experimental results of ammonia volatilization from 13 soils.     

Mutations of the mitochondrial holocytochrome c-type synthase in X-linked dominant microphthalmia with linear skin defects syndrome

The microphthalmia with linear skin defects syndrome (MLS, or MIDAS) is an X-linked dominant male-lethal disorder almost invariably associated with segmental monosomy of the Xp22 region. In two female patients, from two families, with MLS and a normal karyotype, we identified heterozygous de novo point mutations--a missense mutation (p.R217C) and a nonsense mutation (p.R197X)--in the HCCS gene. HCCS encodes the mitochondrial holocytochrome c-type synthase that functions as heme lyase by covalently adding the prosthetic heme group to both apocytochrome c and c(1). We investigated a third family, displaying phenotypic variability, in which the mother and two of her daughters carry an 8.6-kb submicroscopic deletion encompassing part of the HCCS gene. Functional analysis demonstrates that both mutant proteins (R217C and Delta 197-268) were unable to complement a Saccharomyces cerevisiae mutant deficient for the HCCS orthologue Cyc3p, in contrast to wild-type HCCS. Moreover, ectopically expressed HCCS wild-type and the R217C mutant protein are targeted to mitochondria in CHO-K1 cells, whereas the C-terminal-truncated Delta 197-268 mutant failed to be sorted to mitochondria. Cytochrome c, the final product of holocytochrome c-type synthase activity, is implicated in both oxidative phosphorylation (OXPHOS) and apoptosis. We hypothesize that the inability of HCCS-deficient cells to undergo cytochrome c-mediated apoptosis may push cell death toward necrosis that gives rise to severe deterioration of the affected tissues. In summary, we suggest that disturbance of both OXPHOS and the balance between apoptosis and necrosis, as well as the X-inactivation pattern, may contribute to the variable phenotype observed in patients with MLS.     

Cultivation and utilisation of red seaweeds in the Western Indian Ocean (WIO) Region

Seaweed farming in the Western Indian Ocean (WIO) Region is carried out in a number of countries, most of them farming Eucheuma denticulatum, Kappaphycus alvarezii and Kappaphycus striatum. These species are farmed mostly in Tanzania with limited production in Madagascar, Mozambique and Kenya; current production (2012) stands at 15,966 t (dry weight) year^?1 of Eucheuma and Kappaphycus, valued at US$ 4.2 million with 95 % of this tonnage coming from Tanzania. Other countries in the region have limited or no seaweed production owing to problems of epiphytes, ice ice and markets. The problem of epiphytes coupled with ice ice that WIO countries are facing causes die-off of Kappaphycus which is the preferred species in foreign markets for its thicker gel, kappa carrageenan (vs. the weaker iota carrageenan from Eucheuma). New efforts are put to curb these problems including moving seaweed farms to deeper waters and cultivation trials of other carrageenophytes as well as agar-producing species, agarophytes. Research work has been initiated to evaluate Gracilaria and Hypnea farming and processing in Tanzania, the Republic of Mauritius and Mayotte. Gracilaria farming is at experimental stages as a biofilter of fishpond effluents and as potential species for the production of agar with growth rates of 1.5–1.9 % day^?1. Hypnea farming is only being initiated in Mauritius and Mayotte at present. Other innovations including value addition by making various seaweed products and encouraging the consumption of seaweed as food at least in Tanzania and Mauritius are increasing further the importance of the seaweed farming and processing industry in the WIO Region.     

Molecular and functional characterization of voltage-gated sodium channels in human sperm

Background  

We have investigated the expression of voltage-gated sodium channels in human spermatozoa and characterized their role in sperm motility.     

5-HT2 antagonist activity of 3-aminomethyltetralones

The affinity of four 3-aminomethyltetralones for 5-HT₂ receptors is reported, together with their inhibitory activity against serotonin-induced contractions in rat aorta rings stripped of endothelium. Compound 4, which has a p-fluorobenzoyl-piperidine fragment, exhibited activity similar to that of methysergyde.     

The H syndrome is caused by mutations in the nucleoside transporter hENT3

The H syndrome is a recently reported autosomal-recessive disorder characterized by cutaneous hyperpigmentation, hypertrichosis, hepatosplenomegaly, heart anomalies, hearing loss, hypogonadism, short stature, hallux valgus, and fixed flexion contractures of the toe joints and the proximal interphalangeal joints. Homozygosity mapping in five consanguineous families resulted in the identification of mutations in the SLC29A3 gene, which encodes the equilibrative nucleoside transporter hENT3. Three mutations were found in 11 families of Arab and Bulgarian origin. The finding of several different mutations in a small geographic region implies that the H syndrome might be rather common. The identification of mutations in the SLC29A3 gene in patients with a mild clinical phenotype suggests that this is a largely underdiagnosed condition and strongly suggests that even oligosymptomatic individuals might have the disorder.     

Boron and salinity effects on grafted and non-grafted melon plants

Production of melon (Cucumis melo) may be limited by excesses of boron and salinity, and it was hypothesized that melon grafted onto Cucurbita rootstock would be more tolerant to excessive boron concentrations than non-grafted plants. The objectives of this study were (i) to determine the effects of salinity and excessive boron concentrations in irrigation water on growth and yields of grafted and non-grafted melon plants; and (ii) to study the interaction between the effects of salinity and boron on the uptake of macroelements and boron by grafted and non-grafted melon plants. The plants were grown in pots of Perlite in a greenhouse. The combined effects of boron and salinity on growth and yield were investigated for five boron concentrations, ranging from 0.2 to 10 mg L^{− 1}, and two salinity levels, electrical conductivity (EC) 1.8 and 4.6 dS m^{− 1}, in the irrigation water. With low salinity the boron concentrations in old leaves of non-grafted and grafted plants ranged from 249 to 2827 and from 171 to 1651 mg kg^{− 1} dry weight, respectively; with high salinity the corresponding concentrations ranged from 192 to 2221 and from 200 to 1263 mg kg^{− 1} dry weight, respectively. These results indicate that the grafted plants accumulated less boron than the non-grafted plants when they were exposed to similar boron concentrations, and that both plant types absorbed less boron when irrigated with the more saline irrigation water. It is suggested that: (i) the Cucurbita rootstock excluded some boron and that this, in turn, decreased the boron concentration in the grafted plants; and (ii) the low boron uptake under high-salinity irrigation was mainly a result of reduced transpiration of the plants. Significant negative linear regressions were found between fruit yield and leaf boron concentration for grafted plants, under both low and high salinity levels, and for non-grafted plants under low salinity. The fruit yield of the grafted plants was less affected by boron accumulation in the leaves than that of non-grafted plants. Increasing the water salinity decreased the sensitivity of both plant types to increases in leaf boron concentration, which indicates that the effects of boron and salinity on melon plants were not additive.     

Anthropometry Versus Imaging for Prediction of Inflammation Among Hispanic Girls

Objective: This study aimed to compare total and regional estimates of body composition, by direct and indirect techniques, for the optimal prediction of C‐reactive protein (CRP) among young (aged 9‐12 years) Hispanic girls (N = 232). Methods: Standard anthropometric techniques were used to measure height, weight, and waist circumference. Dual‐energy X‐ray absorptiometry (DXA) and peripheral quantitative computed tomography (pQCT) assessed body composition. Fasting serum CRP was measured by the AU5812 Clinical Chemistry Analyzer (Beckman Coulter, Brea, California). Associations between each total and regional body composition parameter and CRP were tested using linear regression (log‐transformed, continuous CRP) and ordinal logistic regression (CRP < 1.0, ≥ 1.0‐2.9, and ≥ 3.0 mg/L), controlling for maturation, dietary energy, physical activity, and medications. Results: All measures of total and regional body fat were positively associated with CRP (P < 0.0001) except for intermuscular fat by pQCT. There were no clinically relevant differences in their association with CRP between anthropometric (BMI; waist circumference) and DXA‐derived (total fat and regional fat: trunk, gynoid, android fat, leg) measures of fat. Conclusions: Measurement of body habitus in Hispanic girls, by multiple commonly available means, predicts CRP equally well.     

Over-Expression of the DM-20 Myelin Proteolipid Causes Central Nervous System Demyelination in Transgenic Mice

Abstract: We have created transgenic mice bearing varying copy numbers of a transgene coding for normal DM-20, the alternatively spliced quantitatively minor isoform of myelin proteolipid protein. Demyelination of the CNS occurs as a consequence of 70 copies of this transgene. Overt symptoms begin at ∼3 months with a wobbling gait. Occasional seizures lasting a few seconds begin at 3–4 months. These symptoms progress in severity with age. Death occurs by 8–10 months. Myelination in 2-month-old animals, before the onset of any overt symptoms, appears morphologically normal at the electron microscopic level. However, the myelin in these 2-month-old animals has a reduced amount of the major myelin proteolipid protein and about three times as much DM-20 as normal animals. In 7-month-old animals that appear to be undergoing demyelination in the CNS, both the major myelin proteolipid protein and DM-20 are greatly reduced relative to the 2-month-old animal. Mice with 17 copies of the transgene also have a reduced amount of the major myelin proteolipid protein but appear to be otherwise normal and have normal life spans (>2 yr). Mice with low copy numbers of the transgene (2–4 copies) appear to be unaffected and have normal life spans.