Phosphorus Efficiency of Cabbage (Brassica oleraceae L. var. capitata), Carrot (Daucus carotaL.), and Potato (Solanum tuberosumL.)

Plant species and genotypes within the same species may differ in phosphorus efficiency. The objective of this research was to study phosphorus efficiency of cabbage (Brassica oleraceae L.), carrot (Daucus carota L.), and potato (Solanum tuberosum L.) and to quantify the contribution of morphological root characteristics to P uptake of the plant species. An experiment was conducted in a glasshouse with six P levels: 0, 12, 27, 73, 124 and 234 mg P kg^–1 soil, and with six replications. Cabbage attained 80% of its maximum yield already at the level of no P supply, whereas carrot and potato reached only 4 and 16% of their highest yields respectively at this level of P supply. This indicated that cabbage was P-efficient compared to carrot and potato. Root/shoot ratio (cm root g^–1 shoot d. m.) increased in the order of cabbage < carrot < potato, and was enhanced at lower P levels. Root hair length was not affected by P level, and averaged 0.22, 0.03 and 0.18 mm for cabbage, carrot, and potato, respectively. Predicting P uptake by a mechanistic simulation model revealed that root hairs contributed about 50% to the total P uptake of cabbage and potato, but only 0.3% to that of carrot. The relationship between the observed P uptake and the predicted P uptake of the plants revealed that model parameters explained nearly 4/5th of the total P uptake of carrot and potato, but only 2/5th of that of cabbage. This showed that the P uptake of cabbage was strongly under-predicted, whereas that of carrot and potato was predicted well. Therefore, it was hypothesised that cabbage may have the ability to mobilise and take up soil P additionally by other root mechanisms such as exudation of organic acids.     

Host density effects on efficacy of entomopathogenic nematodes against white grub (Coleoptera: Scarabaeidae) species

We tested the effect of host density on entomopathogenic nematode efficacy in 1-L pots with grass and soil. In four experiments, combinations ranged from somewhat resistant hosts (oriental beetle, Anomala orientalis, or northern masked chafer, Cyclocephala borealis, with Heterorhabditis bacteriophora) over more susceptible hosts (Japanese beetle, Popillia japonica, with Steinernema glaseri) to a highly susceptible host (P. japonica and S. scarabaei). In each experiment, four larval densities were exposed to two nematode rates over a 14-day period. A significant effect of host density on nematode efficacy occurred only in the A. orientalis–H. bacteriophora combination, but there was no clear trend in the data. This suggests that an exhaustion of available nematode populations to less lethal levels by high host numbers was counteracted by other factors such as increased chances for nematode-host contact and increased host susceptibility due to stress via reduced food resources and increased aggression between larvae.     

Assessment of Anthelmintic Efficacy of Mebendazole in School Children in Six Countries Where Soil-Transmitted Helminths Are Endemic

Background

Robust reference values for fecal egg count reduction (FECR) rates of the most widely used anthelmintic drugs in preventive chemotherapy (PC) programs for controlling soil-transmitted helminths (STHs; Ascaris lumbricoides, Trichuris trichiura, and hookworm) are still lacking. However, they are urgently needed to ensure detection of reduced efficacies that are predicted to occur due to growing drug pressure. Here, using a standardized methodology, we assessed the FECR rate of a single oral dose of mebendazole (MEB; 500 mg) against STHs in six trials in school children in different locations around the world. Our results are compared with those previously obtained for similarly conducted trials of a single oral dose of albendazole (ALB; 400 mg).

Methodology

The efficacy of MEB, as assessed by FECR, was determined in six trials involving 5,830 school children in Brazil, Cambodia, Cameroon, Ethiopia, United Republic of Tanzania, and Vietnam. The efficacy of MEB was compared to that of ALB as previously assessed in 8,841 school children in India and all the above-mentioned study sites, using identical methodologies.

Principal Findings

The estimated FECR rate [95% confidence interval] of MEB was highest for A. lumbricoides (97.6% [95.8; 99.5]), followed by hookworm (79.6% [71.0; 88.3]). For T. trichiura, the estimated FECR rate was 63.1% [51.6; 74.6]. Compared to MEB, ALB was significantly more efficacious against hookworm (96.2% [91.1; 100], p<0.001) and only marginally, although significantly, better against A. lumbricoides infections (99.9% [99.0; 100], p = 0.012), but equally efficacious for T. trichiura infections (64.5% [44.4; 84.7], p = 0.906).

Conclusions/Significance

A minimum FECR rate of 95% for A. lumbricoides, 70% for hookworm, and 50% for T. trichiura is expected in MEB-dependent PC programs. Lower FECR results may indicate the development of potential drug resistance.     

Woody plant diversity,composition and structure in relation to environmental variables and land-cover types in Lake Wanchi watershed,central highlands of Ethiopia

Knowledge of vegetation dynamics associated with human land-use change and environmental variables is crucial for sustainable watershed management. The objective of this study was to analyse woody plant diversity in response to the effects of anthropogenic disturbances, and topographic variables in different land-cover types. Woody plants ≥5 cm diameter at breast height (DBH) were recorded from 20-by-20 m plots, those <5 cm DBH were recorded from 10-by-10 m plots, and tree seedlings were recorded in 3-by-3 m plots. Nonmetric multidimensional scaling with Bray–Curtis distance was employed to analyse woody species composition. Woody species richness was analysed using generalised linear modelling. Tree diameter-class distributions were examined for population structure. The study identified 104 woody plants belonging to 52 families, where 74.5% were indigenous and 16.7% were endemic to Ethiopia. Asteraceae, Fabaceae and Rosaceae were the most species-rich families. There was evidence for the effect of anthropogenic disturbance and elevation on woody species composition. Wetlands contained the highest woody species richness, while woody species richness declined with increasing elevation and disturbance. Evidence of good regeneration was observed in wetlands. To sustain the ecological functions and services provided by the watershed, rehabilitation of the forest and shrub-cover should be a high priority for local management authorities.     

Identification of antigenic linear peptides in the soil-transmitted helminth and Schistosoma mansoni proteome

The scientific community identified non stool-based biomarkers as the way forward to support soil-transmitted helminth (STH; Ascaris lumbricoides, Trichuris trichiura and the hookworms Ancylostoma duodenale and Necator americanus) and schistosome (S. mansoni and S. haematobium) deworming programs. This support is needed in making the decision of whether or not to stop preventive chemotherapy intervention efforts and to ultimately transition towards a post-intervention surveillance phase. We applied a two-step micro-array approach to identify antigenic linear epitopes in the STH and S. mansoni proteomes. In a first experiment, we identified antigenic peptides by applying sera from 24 STH and/or S. mansoni infected Ethiopian children on a high-density peptide microarray containing 3.3 million peptides derived from the complete STH and S. mansoni proteomes. A second array experiment with 170,185 peptides that were recognized in the first array was designed to identify non-specific antibody reactivity by applying sera from 24 healthy individuals from Belgium (a non-endemic country). From this array testing cascade, several peptides were identified for STH but none of them appeared to be unique for one species. We therefore concluded that for STH, none of the peptides revealed to be sufficiently sensitive or species specific. For S. mansoni, some promising peptides were identified prompting future investigation. Based on these results, it is unlikely that linear epitopes would be highly useful in detecting species-specific antibody responses to STH in endemic communities. For S. mansoni, one particular peptide of the micro-exon gene 12 (MEG-12) protein deserves further research. In addition, this study emphasizes the need of well-characterized biobanks for biomarker discovery, particularly when the integration of multiple disease programs is envisioned.     

Biochemical and biophysical characterization of unique switch pocket inhibitors of p38α

Herein we describe the identification and characterization of a class of molecules that are believed to extend into a region of p38 known as the ‘switch pocket’. Although these molecules lack a canonical hinge binding motif, they show K_i values as low as 100 nM against p38. We show that molecules that interact with this region of the protein demonstrate different binding kinetics than a canonical ATP mimetic, as well as a wide range of kinome profiles. Thus, the switch pocket presents new opportunities for kinome selectivity which could result in unique biochemical responses and offer new opportunities in the field of kinase drug discovery.     

Identification and characterization of a small molecule AMPK activator that treats key components of type 2 diabetes and the metabolic syndrome

AMP-activated protein kinase (AMPK) is a key sensor and regulator of intracellular and whole-body energy metabolism. We have identified a thienopyridone family of AMPK activators. A-769662 directly stimulated partially purified rat liver AMPK (EC₅₀ = 0.8 μM) and inhibited fatty acid synthesis in primary rat hepatocytes (IC₅₀ = 3.2 μM). Short-term treatment of normal Sprague Dawley rats with A-769662 decreased liver malonyl CoA levels and the respiratory exchange ratio, VCO₂/VO_2, indicating an increased rate of whole-body fatty acid oxidation. Treatment of ob/ob mice with 30 mg/kg b.i.d. A-769662 decreased hepatic expression of PEPCK, G6Pase, and FAS, lowered plasma glucose by 40%, reduced body weight gain and significantly decreased both plasma and liver triglyceride levels. These results demonstrate that small molecule-mediated activation of AMPK in vivo is feasible and represents a promising approach for the treatment of type 2 diabetes and the metabolic syndrome.     

MNAR plays an important role in ERa activation of Src/MAPK and PI3K/Akt signaling pathways

Estrogens play a critical role in the regulation of cellular proliferation, differentiation, and apoptosis. Evidence indicates that this regulation is mediated by a complex interface of direct control of gene expression (so-called "genomic action") and by regulation of cell-signaling/phosphorylation cascades (referred to as the "non-genomic", or "extranuclear" action). However, the mechanisms of the non-genomic action of estrogens are not well defined. We have recently described the identification of a novel scaffold protein termed MNAR (modulator of non-genomic action of estrogen receptor), that couples conventional steroid receptors with extranuclear signal transduction pathways, thus potentially providing additional and tissue- or cell-specific level of steroid hormone regulation of cell functions. We have demonstrated that the MNAR is required for ER alpha (ERa) interaction with p60(src) (Src), which leads to activation of Src/MAPK pathway. Our new data also suggest that activation of cSrc in response to E2 leads to MNAR phosphorylation, interaction with p85, and activation of the PI3 and Akt kinases. These data therefore suggest that MNAR acts as an important scaffold that integrates ERa action in regulation of important signaling pathways. ERa non-genomic action has been suggested to play a key role in estrogen-induced cardio-, neuro-, and osteo-protection. Therefore, evaluation of the molecular crosstalk between MNAR and ERa may lead to development of functionally selective ER modulators that can separate between beneficial, prodifferentiative effects in bone, the cardiovascular system and the CNS and the "detrimental", proliferative effects in reproductive tissues and organs.     

Attempts to revive Mycobacterium tuberculosis from 300-year-old human mummies

Environmental persistence of Mycobacterium tuberculosis is subject to speculation. However, the reality that infected postmortem tissues can be a danger to pathologists and embalmers has worrisome implications. A few experimental studies have demonstrated the organism's ability to withstand exposure to embalming fluid and formalin. Recently, a failure was reported in an attempt to resuscitate an original isolate of Robert Koch to determine the lifetime of the tubercle bacillus. The present study also considers a historical approach to determine persistence under favorable environmental conditions. It asks whether acid-fast forms observed in tissues of 300-year-old Hungarian mummies can be resuscitated. Finding organisms before the advent of antibiotics and pasteurization may yield valuable genetic information. Using various media modifications, as well as guinea pig inoculation, an attempt was made to culture these tissues for M. tuberculosis. In addition, a resuscitation-promoting factor, known to increase colony counts in high G+C bacteria, was applied to the cultures. Although an occasional PCR-positive sample was detected, no colonies of M. tuberculosis were obtained. Our results may indicate that the life span of the tubercle bacillus is less than a few hundred years, even though in the short run it can survive harsh chemical treatment.