264 research outputs found
Similar strains of Burkholderia spp. nodulate the South African invasive legume Dipogon lignosus in New Zealand and Australian soils
Brazil and South Africa are centres of diversity of Burkholderia ssp. that nodulate legumes (Gyaneschwar et al, 2011; Beukes et al. 2013). The nod gene sequence of Burkholderia spp, capable of nodulating South Africa plants are clearly separated from those of Burkholderia spp. shown to nodulate South American plants. Where tested, the South African strains did not nodulate South American plants nodulated by Burkholderia spp. (Gyaneschwar et al. 2011)
Denial at the top table: status attributions and implications for marketing
Senior marketing management is seldom represented on the Board of Directors nowadays, reflecting a deteriorating status of the marketing profession. We examine some of the key reasons for marketing’s demise, and discuss how the status of marketing may be restored by demonstrating the value of marketing to the business community. We attribute marketing’s demise to several related key factors: narrow typecasting, marginalisation and limited involvement in product development, questionable marketing curricula, insensitivity toward environmental change, questionable professional standards and roles, and marketing’s apparent lack of accountability to CEOs. Each of these leads to failure to communicate, create, or deliver value within marketing. We argue that a continued inability to deal with marketing’s crisis of representation will further erode the status of the discipline both academically and professionally
Complete genome sequence of the Medicago microsymbiont Ensifer (Sinorhizobium) medicae strain WSM419
Ensifer (Sinorhizobium) medicae is an effective nitrogen fixing microsymbiont of a diverse range of annual Medicago (medic) species. Strain WSM419 is an aerobic, motile, non-spore forming, Gram-negative rod isolated from a M. murex root nodule collected in Sardinia, Italy in 1981. WSM419 was manufactured commercially in Australia as an inoculant for annual medics during 1985 to 1993 due to its nitrogen fixation, saprophytic competence and acid tolerance properties. Here we describe the basic features of this organism, together with the complete genome sequence, and annotation. This is the first report of a complete genome se-quence for a microsymbiont of the group of annual medic species adapted to acid soils. We reveal that its genome size is 6,817,576 bp encoding 6,518 protein-coding genes and 81 RNA only encoding genes. The genome contains a chromosome of size 3,781,904 bp and 3 plasmids of size 1,570,951 bp, 1,245,408 bp and 219,313 bp. The smallest plasmid is a fea-ture unique to this medic microsymbiont
Biogeography of nodulated legumes and their nitrogen-fixing symbionts
In the last decade, analyses of both molecular and morphological characters, including nodulation, have led to major changes in our understanding of legume taxonomy. In parallel there has been an explosion in the number of genera and species of rhizobia known to nodulate legumes. No attempt has been made to link these two sets of data or to consider them in a biogeographical context. This review aims to do this by relating the data to the evolution of the two partners: it highlights both longitudinal and latitudinal trends and considers these in relation to the location of major land masses over geological time. Australia is identified as being a special case and latitudes north of the equator as being pivotal in the evolution of highly specialized systems in which the differentiated rhizobia effectively become ammonia factories. However, there are still many gaps to be filled before legume nodulation is sufficiently understood to be managed for the benefit of a world in which climate change is rife
Modelling the Role of UCH-L1 on Protein Aggregation in Age-Related Neurodegeneration
Overexpression of the de-ubiquitinating enzyme UCH-L1 leads to inclusion formation in response to proteasome impairment. These inclusions contain components of the ubiquitin-proteasome system and α-synuclein confirming that the ubiquitin-proteasome system plays an important role in protein aggregation. The processes involved are very complex and so we have chosen to take a systems biology approach to examine the system whereby we combine mathematical modelling with experiments in an iterative process. The experiments show that cells are very heterogeneous with respect to inclusion formation and so we use stochastic simulation. The model shows that the variability is partly due to stochastic effects but also depends on protein expression levels of UCH-L1 within cells. The model also indicates that the aggregation process can start even before any proteasome inhibition is present, but that proteasome inhibition greatly accelerates aggregation progression. This leads to less efficient protein degradation and hence more aggregation suggesting that there is a vicious cycle. However, proteasome inhibition may not necessarily be the initiating event. Our combined modelling and experimental approach show that stochastic effects play an important role in the aggregation process and could explain the variability in the age of disease onset. Furthermore, our model provides a valuable tool, as it can be easily modified and extended to incorporate new experimental data, test hypotheses and make testable predictions
Pandora's email box? An exploratory study of Web-based email forgery detection and validation
Web based email systems may be a source of pristine digital evidence because of the perceived difficulty of client tampering with messages stored inside the email account. We demonstrate that such assumption is wrong in the case of Windows Live Hotmail®1. Windows Live Mail®1 synchronises message on client-side computers with the Hotmail® server, benefiting users wishing to synchronise their email accounts and personal devices. However, this synchronisation opens an exploit for wrongdoers to tamper with existing email messages and attachments as well as facilitating the insertion of fabricated messages. The exploit process enables persistent storage of tampered and fabricated messages on the Hotmail®1 server. The exploitation favours both account owners and wrongdoers who gain unauthorised access of others’ accounts. Even if tampering were suspected, we anticipate some difficulties in validating messages to determine their reliability and relevance. We predict, with trepidation, that the exploit process will become commonplace and pose greater challenges to the cyber forensics examiner and legal practitioner during investigations and legal proceedings. Regrettably, the exploit complements the existing arsenal of tools for email forgery. More ominously, it provides opportunity for traceless injection of illicit material/malware onto any machine synchronised with the Hotmail® account
Laparoscopy in management of appendicitis in high-, middle-, and low-income countries: a multicenter, prospective, cohort study.
BACKGROUND: Appendicitis is the most common abdominal surgical emergency worldwide. Differences between high- and low-income settings in the availability of laparoscopic appendectomy, alternative management choices, and outcomes are poorly described. The aim was to identify variation in surgical management and outcomes of appendicitis within low-, middle-, and high-Human Development Index (HDI) countries worldwide. METHODS: This is a multicenter, international prospective cohort study. Consecutive sampling of patients undergoing emergency appendectomy over 6 months was conducted. Follow-up lasted 30 days. RESULTS: 4546 patients from 52 countries underwent appendectomy (2499 high-, 1540 middle-, and 507 low-HDI groups). Surgical site infection (SSI) rates were higher in low-HDI (OR 2.57, 95% CI 1.33-4.99, p = 0.005) but not middle-HDI countries (OR 1.38, 95% CI 0.76-2.52, p = 0.291), compared with high-HDI countries after adjustment. A laparoscopic approach was common in high-HDI countries (1693/2499, 67.7%), but infrequent in low-HDI (41/507, 8.1%) and middle-HDI (132/1540, 8.6%) groups. After accounting for case-mix, laparoscopy was still associated with fewer overall complications (OR 0.55, 95% CI 0.42-0.71, p < 0.001) and SSIs (OR 0.22, 95% CI 0.14-0.33, p < 0.001). In propensity-score matched groups within low-/middle-HDI countries, laparoscopy was still associated with fewer overall complications (OR 0.23 95% CI 0.11-0.44) and SSI (OR 0.21 95% CI 0.09-0.45). CONCLUSION: A laparoscopic approach is associated with better outcomes and availability appears to differ by country HDI. Despite the profound clinical, operational, and financial barriers to its widespread introduction, laparoscopy could significantly improve outcomes for patients in low-resource environments. TRIAL REGISTRATION: NCT02179112
The Genome of the Acid Soil-Adapted Strain Rhizobium favelukesii OR191 Encodes Determinants for Effective Symbiotic Interaction With Both an Inverted Repeat Lacking Clade and a Phaseoloid Legume Host
Although Medicago sativa forms highly effective symbioses with the comparatively acid-sensitive genus Ensifer, its introduction into acid soils appears to have selected for symbiotic interactions with acid-tolerant R. favelukesii strains. Rhizobium favelukesii has the unusual ability of being able to nodulate and fix nitrogen, albeit sub-optimally, not only with M. sativa but also with the promiscuous host Phaseolus vulgaris. Here we describe the genome of R. favelukesii OR191 and genomic features important for the symbiotic interaction with both of these hosts. The OR191 draft genome contained acid adaptation loci, including the highly acid-inducible lpiA/acvB operon and olsC, required for production of lysine- and ornithine-containing membrane lipids, respectively. The olsC gene was also present in other acid-tolerant Rhizobium strains but absent from the more acid-sensitive Ensifer microsymbionts. The OR191 symbiotic genes were in general more closely related to those found in Medicago microsymbionts. OR191 contained the nodA, nodEF, nodHPQ, and nodL genes for synthesis of polyunsaturated, sulfated and acetylated Nod factors that are important for symbiosis with Medicago, but contained a truncated nodG, which may decrease nodulation efficiency with M. sativa. OR191 contained an E. meliloti type BacA, which has been shown to specifically protect Ensifer microsymbionts from Medicago nodule-specific cysteine-rich peptides. The nitrogen fixation genes nifQWZS were present in OR191 and P. vulgaris microsymbionts but absent from E. meliloti-Medicago microsymbionts. The ability of OR191 to nodulate and fix nitrogen symbiotically with P. vulgaris indicates that this host has less stringent requirements for nodulation than M. sativa but may need rhizobial strains that possess nifQWZS for N2-fixation to occur. OR191 possessed the exo genes required for the biosynthesis of succinoglycan, which is required for the Ensifer-Medicago symbiosis. However, 1H-NMR spectra revealed that, in the conditions tested, OR191 exopolysaccharide did not contain a succinyl substituent but instead contained a 3-hydroxybutyrate moiety, which may affect its symbiotic performance with Medicago hosts. These findings provide a foundation for the genetic basis of nodulation requirements and symbiotic effectiveness with different hosts
The innovation of the symbiosome has enhanced the evolutionary stability of nitrogen fixation in legumes
Nitrogen-fixing symbiosis is globally important in ecosystem functioning and agriculture, yet the evolutionary history of nodulation remains the focus of considerable debate. Recent evidence suggesting a single origin of nodulation followed by massive parallel evolutionary losses raises questions about why a few lineages in the N2-fixing clade retained nodulation and diversified as stable nodulators, while most did not. Within legumes, nodulation is restricted to the two most diverse subfamilies, Papilionoideae and Caesalpinioideae, which show stable retention of nodulation across their core clades.
We characterize two nodule anatomy types across 128 species in 56 of the 152 genera of the legume subfamily Caesalpinioideae: fixation thread nodules (FTs), where nitrogen-fixing bacteroids are retained within the apoplast in modified infection threads, and symbiosomes, where rhizobia are symplastically internalized in the host cell cytoplasm within membrane-bound symbiosomes (SYMs).
Using a robust phylogenomic tree based on 997 genes from 147 Caesalpinioideae genera, we show that losses of nodulation are more prevalent in lineages with FTs than those with SYMs.
We propose that evolution of the symbiosome allows for a more intimate and enduring symbiosis through tighter compartmentalization of their rhizobial microsymbionts, resulting in greater evolutionary stability of nodulation across this species-rich pantropical legume clade
High-quality draft genome sequence of Rhizobium mesoamericanum strain STM6155, a Mimosa pudica microsymbiont from New Caledonia.
Rhizobium mesoamericanum STM6155 (INSCD?=?ATYY01000000) is an aerobic, motile, Gram-negative, non-spore-forming rod that can exist as a soil saprophyte or as an effective nitrogen fixing microsymbiont of the legume Mimosa pudica L.. STM6155 was isolated in 2009 from a nodule of the trap host M. pudica grown in nickel-rich soil collected near Mont Dore, New Caledonia. R. mesoamericanum STM6155 was selected as part of the DOE Joint Genome Institute 2010 Genomic Encyclopedia for Bacteria and Archaea-Root Nodule Bacteria (GEBA-RNB) genome sequencing project. Here we describe the symbiotic properties of R. mesoamericanum STM6155, together with its genome sequence information and annotation. The 6,927,906 bp high-quality draft genome is arranged into 147 scaffolds of 152 contigs containing 6855 protein-coding genes and 71 RNA-only encoding genes. Strain STM6155 forms an ANI clique (ID 2435) with the sequenced R. mesoamericanum strain STM3625, and the nodulation genes are highly conserved in these strains and the type strain of Rhizobium grahamii CCGE501(T). Within the STM6155 genome, we have identified a chr chromate efflux gene cluster of six genes arranged into two putative operons and we postulate that this cluster is important for the survival of STM6155 in ultramafic soils containing high concentrations of chromate
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