Caspase‐1 inflammasome activity in patients with Staphylococcus aureus bacteremia

The inflammasome is a multiprotein complex that mediates caspase‐1 activation with subsequent maturation of the proinflammatory cytokines IL‐1β and IL‐18. The NLRP3 inflammasome is known to be activated by Staphylococcus aureus, one of the leading causes of bacteremia worldwide. Inflammasome activation and regulation in response to bacterial infection have been found to be of importance for a balanced host immune response. However, inflammasome signaling in vivo in humans initiated by S. aureus is currently sparsely studied. This study therefore aimed to investigate NLRP3 inflammasome activity in 20 patients with S. aureus bacteremia (SAB), by repeated measurement during the first week of bacteremia, compared with controls. Caspase‐1 activity was measured in monocytes and neutrophils by flow cytometry detecting FLICA (fluorescent‐labeled inhibitor of caspase‐1), while IL‐1β and IL‐18 was measured by Luminex and ELISA, respectively. As a measure of inflammasome priming, messenger RNA (mRNA) expression of NLRP3, CASP1 (procaspase‐1), and IL1B (pro‐IL‐1β) was analyzed by quantitative PCR. We found induced caspase‐1 activity in innate immune cells with subsequent release of IL‐18 in patients during the acute phase of bacteremia, indicating activation of the inflammasome. There was substantial interindividual variation in caspase‐1 activity between patients with SAB. We also found an altered inflammasome priming with low mRNA levels of NLRP3 accompanied by elevated mRNA levels of IL1B. This increased knowledge of the individual host immune response in SAB could provide support in the effort to optimize management and treatment of each individual patient.     

Diversity of sporadic symbionts and nonsymbiotic endophytic bacteria isolated from nodules of woody, shrub, and food legumes in Ethiopia

Fifty-five bacterial isolates were obtained from surface-sterilized nodules of woody and shrub legumes growing in Ethiopia: Crotalaria spp., Indigofera spp., and Erythrina brucei, and the food legumes soybean and common bean. Based on partial 16S rRNA gene sequence analysis, the majority of the isolates were identified as Gram-negative bacteria belonging to the genera Achromobacter, Agrobacterium, Burkholderia, Cronobacter, Enterobacter, Mesorhizobium, Novosphingobium, Pantoea, Pseudomonas, Rahnella, Rhizobium, Serratia, and Variovorax. Seven isolates were Gram-positive bacteria belonging to the genera Bacillus, Paenibacillus, Planomicrobium, and Rhodococcus. Amplified fragment length polymorphism (AFLP) fingerprinting showed that each strain was genetically distinct. According to phylogenetic analysis of recA, glnII, rpoB, and 16S rRNA gene sequences, Rhizobium, Mesorhizobium, and Agrobacterium were further classified into six different genospecies: Agrobacterium spp., Agrobacterium radiobacter, Rhizobium sp., Rhizobium phaseoli, Mesorhizobium sp., and putative new Rhizobium species. The strains from R. phaseoli, Rhizobium sp. IAR30, and Mesorhizobium sp. ERR6 induced nodules on their host plants. The other strains did not form nodules on their original host. Nine endophytic bacterial strains representing seven genera, Agrobacterium, Burkholderia, Paenibacillus, Pantoea, Pseudomonas, Rhizobium, and Serratia, were found to colonize nodules of Crotalaria incana and common bean on co-inoculation with symbiotic rhizobia. Four endophytic Rhizobium and two Agrobacterium strains had identical nifH gene sequences with symbiotic Rhizobium strains, suggesting horizontal gene transfer. Most symbiotic and nonsymbiotic endophytic bacteria showed plant growth-promoting properties in vitro, which indicate their potential role in the promotion of plant growth when colonizing plant roots and the rhizosphere.     

Quantitative trait loci for rooting pattern traits of common beans grown under drought stress versus non-stress conditions

Drought is the major abiotic constraint contributing to yield reduction in common bean (Phaseolus vulgaris L.) worldwide. An increasing scarcity of water in the future will make improving adaptation to drought stress a major objective of most crop breeding efforts. Drought avoidance by increased extraction of soil moisture from greater depth under drought conditions is an adaptive mechanism of common bean. A recombinant inbred line population of DOR364?×?BAT477 was evaluated for rooting pattern traits in soil cylinder tubes under soil drying (progressive water stress) and non-stress (well-watered with 80% of field capacity) treatments in a greenhouse. One of the parents, BAT 477, is a deep-rooting genotype while the other parent, DOR 364, is a commercial cultivar in Central America. The recombinant inbred line population expressed quantitative variation and transgressive segregation for ten rooting pattern traits as well as five shoot traits of 48-day-old plants. A mixed model quantitative trait locus (QTL) mapping analysis was carried out using a genetic map constructed with 165 genetic markers that covered 11 linkage groups of the common bean genome. Genotype estimates were calculated from best design and spatial effects model for each trait. A total of 15 putative QTL were identified for seven rooting pattern traits and four shoot traits. The QTL detected were scattered over five of the 11 linkage groups. The QTL detected for all the root traits except total root length and fine root length were main effect QTL and did not interact with the level of water supply. The total root length and fine root length QTL with significant QTL?×?environment interaction only differed in magnitude of effect, and interaction was of a non-crossover type. Other QTL for total root length, fine roots, thick roots, root volume and root biomass were co-localized and also explained relatively more genetic variance. This suggests that the QTL affecting root traits in common beans are based on constitutive expression of genes and that drought avoidance based on deep rooting, longer root length, thicker roots, increasing root length distribution with depth, root volume and root biomass can be used in molecular breeding. The positive alleles for most of the QTL detected in this study were derived from the paternal parent BAT477. The results from the present analyses highlighted the feasibility of marker-aided selection as an alternative to conventional labor-intensive, phenotypic screening of drought avoidance root traits.     

Phosphorylation of Calcineurin at a Novel Serine-Proline Rich Region Orchestrates Hyphal Growth and Virulence in Aspergillus fumigatus

The fungus Aspergillus fumigatus is a leading infectious killer in immunocompromised patients. Calcineurin, a calmodulin (CaM)-dependent protein phosphatase comprised of calcineurin A (CnaA) and calcineurin B (CnaB) subunits, localizes at the hyphal tips and septa to direct A. fumigatus invasion and virulence. Here we identified a novel serine-proline rich region (SPRR) located between two conserved CnaA domains, the CnaB-binding helix and the CaM-binding domain, that is evolutionarily conserved and unique to filamentous fungi and also completely absent in human calcineurin. Phosphopeptide enrichment and tandem mass spectrometry revealed the phosphorylation of A. fumigatus CnaA in vivo at four clustered serine residues (S406, S408, S410 and S413) in the SPRR. Mutation of the SPRR serine residues to block phosphorylation led to significant hyphal growth and virulence defects, indicating the requirement of calcineurin phosphorylation at the SPRR for its activity and function. Complementation analyses of the A. fumigatus ΔcnaA strain with cnaA homologs from the pathogenic basidiomycete Cryptococcus neoformans, the pathogenic zygomycete Mucor circinelloides, the closely related filamentous fungi Neurospora crassa, and the plant pathogen Magnaporthe grisea, revealed filamentous fungal-specific phosphorylation of CnaA in the SPRR and SPRR homology-dependent restoration of hyphal growth. Surprisingly, circular dichroism studies revealed that, despite proximity to the CaM-binding domain of CnaA, phosphorylation of the SPRR does not alter protein folding following CaM binding. Furthermore, mutational analyses in the catalytic domain, CnaB-binding helix, and the CaM-binding domains revealed that while the conserved PxIxIT substrate binding motif in CnaA is indispensable for septal localization, CaM is required for its function at the hyphal septum but not for septal localization. We defined an evolutionarily conserved novel mode of calcineurin regulation by phosphorylation in filamentous fungi in a region absent in humans. These findings suggest the possibility of harnessing this unique SPRR for innovative antifungal drug design to combat invasive aspergillosis.     

Genetic and non-genetic parameter estimates for growth traits and Kleiber ratios in Dorper × indigenous sheep

Genetic improvement programme will only be successful when accompanied by a good understanding of the influence of different environmental factors, knowledge of the genetic parameters and the genetic relationships between the traits of interest. This study aimed to evaluate the influence of non-genetic factors on growth traits and Kleiber ratios and to estimate genetic parameters for early growth traits in Dorper × indigenous crossbred sheep. The effects of fixed factors were analysed by the general linear model procedure of statistical analysis system, while the genetic parameters were estimated using a WOMBAT computer program fitted animal model. The overall least-square mean for birth weight (BRW), weaning weight (3MW), six-month weight, nine-month weight, and yearling weight were 3.03 ± 0.02, 14.5 ± 0.18, 20.4 ± 0.26, 24.8 ± 0.31, and 28.3 ± 0.40 kg, respectively. The overall least-square mean for Kleiber ratio from birth to weaning (KR1), weaning to six months, six to nine months and nine months to yearling age were 16.8 ± 0.10, 6.41 ± 0.17, 4.55 ± 0.21 and 3.38 ± 0.20 g/kg of metabolic weight, respectively. The inclusion of maternal genetic effect had a significant influence on BRW, and it explains 20% of the phenotypic variation. The total heritability estimates for BRW, 3MW, birth to weaning average daily weight gain and KR1 were 0.10, 0.14, 0.16 and 0.12, respectively. The phenotypic correlation varied from ?0.11 ± 0.05 to 0.98 ± 0.02, whereas the direct genetic correlation ranged from ?0.32 ± 0.40 to 0.98 ± 0.17. The mean inbreeding coefficient was 0.105% with an annual rate of 0.02%. The heritability estimates for growth traits and Kleiber ratio suggest that slow genetic progress would be expected from the selection. However, the integration of selection with crossbreeding programme can enhance genetic gain. Therefore, selection should be conducted based on breeding values estimated from multiple information sources to increase the selection response.     

Micronutrient deficiency and the prevalence of mothers' overweight/obesity in Egypt.

I examine the relationship between micronutrient deficiency and the prevalence of mothers' overweight/obesity in Egypt using the 1997 Egyptian Integrated Household Survey. The ordered logit results show an overlap between micronutrient deficiency and the prevalence of mothers' overweight/obesity in Egypt. The odds of being overweight/obese are 80.8% higher for micronutrient deficient mothers than for non-deficient mothers, keeping all other variables constant. These results have at least two interesting policy implications. First, as the potential impact of the interaction between micronutrient deficiency and chronic diseases is not well known, the coexistence of micronutrient deficient and overweight/obese women can raise new and serious public health problems in the country. Second, the Egyptian food subsidy program, which lowers the relative prices of energy-dense, nutrient-poor food items, can be one of the major factors for the emergence of overweight/obese and micronutrient deficient mothers in the country. Changing the orientation of the food subsidy program may help to simultaneously address this double burden of mothers' malnutrition.     

Response of soil δ15N and nutrients to eastern red cedar (Juniperus virginiana) encroachment into a relict calcareous prairie

The calcareous prairies of Louisiana have been threatened by the encroachment of woody plants, primarily eastern red cedar (Juniperus virginiana). The restoration and management of these rare plant communities require a thorough understanding of the soils supporting them. The knowledge of whether eastern red cedar encroachment has altered these soils is also of interest. We studied the depth distribution, at contrasting vegetation types (prairie, transition, forest) and landscape positions, of ¹⁵N, total N, organic C, C/N ratio, Ca, Mg, K and pH of three relict prairie-forest associations in north central Louisiana, USA. The effect of vegetation type was significant for soil ¹⁵N and Ca. Plant leaf samples from prairie, transition, and forest showed similar ¹⁵N signals, and mean values ranged between –1.6 and –1.1. The order of soil ¹⁵N enrichment of the 0–10cm depth relative to corresponding leaves was forest soil> transition soil>prairie soil. The forest soil was significantly enriched with ¹⁵N compared with the prairie soil and transition soil. Except for C/N ratio, all the soil properties significantly decreased with depth while ¹⁵N increased with depth. Significant differences in C/N ratio, Ca and Mg were associated with landscape position. The change in soil pH due to woody encroachment was restricted to the 0–10cm depth. The results suggest that the prairie soil was distinctly different from the forest soil and that the vegetation at transition (encroaching woody plants) was altering the surface soil pH towards forest-like conditions.     

Edible oil crops and their integration with the major cereals in North Shewa and South Welo,Central Highlands of Ethiopia: an ethnobotanical perspective

A total of 1050 sorghum (Sorghum bicolor) and tef (Eragrostis tef) fields distributed in six study sites within north Shewa and south Welo (Central Highlands of Ethiopia) were systematically surveyed to examine the status of integration of edible oil crops into the cereal-based farming system. Farmers' criteria for, and perception on, integration between edible oil crops and the major cereals at field level as well as integration between the cereal grains and the oilseeds in food making at home were studied and analyzed based on formal semi-structured interview and informal discussion with local expert farmers as key informants. Farmers' traditional space optimization technique has been instrumental in rightly fitting edible oil crops (as intercrops and border crops) into the cereal-based system. Six species of edible oil crops are integrated (70.3%) in various proportions in fields of sorghum and tef. At least one oil crop was significantly intercropped and/or border cropped in sorghum fields. Noog (Guizotia abyssinica) and sesame (Sesamum indicum) were the most important edible oil crops of the study area having strong integration with sorghum both at field and home level. On average, noog was more frequently intercropped with sorghum (8.3%) than with tef (4.5%), while it was more frequently border cropped with tef (32.4%) than with sorghum (19%). Sorghum was more frequently inter/border cropped with sesame (39/2%) than with tef (10.1/0.5%). The stronger the integration of a given oilseed with sorghum-based foods, the higher the companionship between sorghum fields and the oil crop in the landscape. This cultural practice by farmers has positive contributions to on-farm conservation of oil crops along with tef and specific sorghum landraces. The central theme of this paper therefore converges on the issue of on-farm in-situ agrobiodiversity conservation that was shaped by successive ancestral generations and passed on to the present.