Archaeal host cells infected by Sulfolobus turreted icosahedral virus (STIV) and Sulfolobus islandicus rod-shaped virus 2 (SIRV2) produce unusual pyramid-like structures on the cell surface prior to virus-induced cell lysis. This viral lysis process is distinct from known viral lysis processes associated with bacterial or eukaryal viruses. The STIV protein C92 and the SIRV2 protein 98 are the only viral proteins required for the formation of the pyramid lysis structures of STIV and SIRV2, respectively. Since SIRV2 and STIV have fundamentally different morphotypes and genome sequences, it is surprising that they share this lysis system. In this study, we have constructed a collection of C92/P98 chimeric proteins and tested their abilities, both in the context of virus replication and alone, to form pyramid lysis structures in S. solfataricus. The results of this study illustrate that these proteins are functionally homologous when expressed as individual chimeric proteins but not when expressed in the context of complete STIV infection.
Background and Aims
Simple indicators of crop and cultivar performance across a range of soil types and management are needed for designing and testing sustainable cropping practices. This paper determined the extent to which soil chemical and physical properties, particularly soil strength and pore-size distribution influences root elongation in a wide range of agricultural top soils, using a seedling-based indicator.
Intact soil cores were sampled from the topsoil of 59 agricultural fields in Scotland, representing a wide geographic spread, range of textures and management practices. Water release characteristics, dry bulk density and needle penetrometer resistance were measured on three cores from each field. Soil samples from the same locations were sieved, analysed for chemical characteristics, and packed to dry bulk density of 1·0 g cm−3 to minimize physical constraints. Root elongation rates were determined for barley seedlings planted in both intact field and packed soil cores at a water content close to field capacity (–20 kPa matric potential).
Root elongation in field soil was typically less than half of that in packed soils. Penetrometer resistance was typically between 1 and 3 MPa for field soils, indicating the soils were relatively hard, despite their moderately wet condition (compared with <0·2 MPa for packed soil). Root elongation was strongly linked to differences in physical rather than chemical properties. In field soil root elongation was related most closely to the volume of soil pores between 60 µm and 300 µm equivalent diameter, as estimated from water-release characteristics, accounting for 65·7 % of the variation in the elongation rates.
Root elongation rate in the majority of field soils was slower than half of the unimpeded (packed) rate. Such major reductions in root elongation rates will decrease rooting volumes and limit crop growth in soils where nutrients and water are scarce.
Root elongation; abiotic stress; soil chemistry; soil porosity; soil strength; Scotland; macroporosity; dry bulk density; barley; Hordeum vulgare; pore diameter
Introduction. Non Hodgkin lymphoma (NHL) presenting with obstructive jaundice is a rare occurrence. Because of rarity of combination, it is seldom considered in differential diagnosis of patients presenting with obstructive jaundice. It is considered treatable due to the chemosensitive nature of the disease and the recent advances in chemotherapy. Case Series. We present a case series of 2 patients with NHL presenting with obstructive jaundice as an initial manifestation. Both patients presented with obstructive jaundice and were diagnosed by CT guided liver biopsy. One patient died of sepsis and multiorgan failure before initiating chemotherapy and the second patient did not choose to undergo chemotherapy. Conclusion. Biliary obstruction is a sign of poor prognosis. The diagnosis of NHL needs to be considered in patients presenting with biliary obstruction. It can be associated with high mortality and poses treatment dilemma.
Zulfi Bhutta and colleagues lay out research priorities for global child diarrheal disease over the next 15 years, which they developed using the Child Health and Nutrition Research Initiative (CHNRI) method.
Please see later in the article for the Editors' Summary
A DTPA-Gd containing polymer was grown in the interior of a heat shock protein cage resulting in T1 particle relaxivities of 4,200mM-1 sec-1 for the 12nm particle. Relaxivity parameters were determined and this analysis suggests that the rotational correlation time has been optimized while the water exchange life time is slower than optimal. This synthetic approach holds much promise for the development of next generation contrast agents and this report will aid in their design.
Hyperthermophilic archaeal viruses including Sulfolobus spindle-shaped viruses (SSVs) such as SSV-1 and SSV-Ragged Hills exhibit remarkable morphology and genetic diversity. However, they remain poorly understood, in part because their genomes exhibit limited or unrecognizable sequence similarity to genes with known function. Here we report structural and functional studies of E73, a 73-residue homodimeric protein encoded within the SSV-Ragged Hills genome. Despite lacking significant sequence similarity, the NMR structure reveals clear similarity to ribbon-helix-helix (RHH) domains present in numerous proteins involved in transcriptional regulation. In vitro dsDNA binding experiments confirm the ability of E73 to bind dsDNA in a non-specific manner with micromolar affinity, and characterization of the K11E variant confirms the location of the predicted DNA binding surface. E73 is distinct, however, from known RHHs. The RHH motif is elaborated upon by the insertion of a third helix that is tightly integrated into the structural domain, giving rise to the “RH3” fold. Within the homodimer, this helix results in the formation of a conserved, symmetric cleft distal to the DNA binding surface, where it may mediate protein-protein interactions, or contribute to the high thermal stability of E73. Analysis of backbone amide dynamics by NMR provides evidence for a rigid core, and fast ps-ns timescale NH bond vector motions for residues located within the antiparallel β-sheet region of the proposed DNA-binding surface, and slower μs to ms timescale motions for residues in the α1-α2 loop. The role of E73 and its SSV homologs in the viral life cycle are discussed.
Where there is life, there are viruses. The impact of viruses on evolution, global nutrient cycling, and disease has driven research on their cellular and molecular biology. Knowledge exists for a wide range of viruses, however, a major exception are viruses with archaeal hosts. Archaeal virus-host systems are of great interest because they have similarities to both eukaryotic and bacterial systems and often live in extreme environments. Here we report the first proteomics-based experiments on archaeal host response to viral infection. Sulfolobus Turreted Icosahedral Virus (STIV) infection of Sulfolobus solfataricus P2 was studied using 1D and 2D differential gel electrophoresis (DIGE) to measure abundance and redox changes. Cysteine reactivity was measured using novel fluorescent zwitterionic chemical probes that, together with abundance changes, suggest that virus and host are both vying for control of redox status in the cells. Proteins from nearly 50% of the predicted viral open reading frames were found along with a new STIV protein with a homolog in STIV2. This study provides insight to features of viral replication novel to the archaea, makes strong connections to well described mechanisms used by eukaryotic viruses such as ESCRT-III mediated transport, and emphasizes the complementary nature of different omics approaches.
Archaea; virus infection; Sulfolobus solfataricus strain P2; STIV; Sulfolobus turreted icosahedral virus; Proteomics; virus–host interaction; LC/MS/MS; liquid chromatography mass spectrometry; differential gene expression; membrane protein; VAPs; Virus-associated pyramids; 2-D Fluorescence Difference Gel Electrophoresis; Thiol-reactive maleimide probe
The first structure of a catalytic domain from a hyperthermophilic archaeal viral integrase reveals a minimal fold similar to that of bacterial HP1 integrase and defines structural elements conserved across three domains of life. However, structural superposition on bacterial Holliday junction complexes and similarities in the C-terminal tail with that of eukaryotic Flp suggest that the catalytic tyrosine and an additional active-site lysine are delivered to neighboring subunits in trans. An intramolecular disulfide bond contributes significant thermostability in vitro.
Paragangliomas are very rare tumors derived from neuroendocrine cells of autonomic nervous system. Extra-adrenal paragangliomas account for only 10 to 15% of all paragangliomas and may present incidentally as a mass. Typical triad of fluctuating hypertension, headache, and sweating is not always present which makes the diagnosis difficult sometimes. Definitive diagnosis is usually made with histologic findings and surgery is the treatment of choice. We report a case of a 53-year-old male who presented with chest pain and vomiting.
Marine deposits from the Callovian of Europe have yielded numerous species of metriorhynchid crocodylomorphs. While common in English and French Formations, metriorhynchids are poorly known from the Iberian Peninsula. Twenty years ago an incomplete, but beautifully preserved, skull was discovered from the Middle Callovian of Spain. It is currently the oldest and best preserved metriorhynchid specimen from the Iberian Peninsula. Until now it has never been properly described and its taxonomic affinities remained obscure.
Here we present a comprehensive description for this specimen and in doing so we refer it to a new genus and species: Maledictosuchus riclaensis. This species is diagnosed by numerous autapomorphies, including: heterodont dentition; tightly interlocking occlusion; lachrymal anterior process excludes the jugal from the preorbital fenestra; orbits longer than supratemporal fenestrae; palatine has two non-midline and one midline anterior processes. Our phylogenetic analysis finds Maledictosuchus riclaensis to be the basal-most known member of Rhacheosaurini (the subclade of increasingly mesopelagic piscivores that includes Cricosaurus and Rhacheosaurus).
Our description of Maledictosuchus riclaensis shows that the craniodental morphologies that underpinned the success of Rhacheosaurini in the Late Jurassic and Early Cretaceous, as a result of increasing marine specialization to adaptations for feeding on fast small-bodied prey (i.e. divided and retracted external nares; reorientation of the lateral processes of the frontal; elongate, tubular rostrum; procumbent and non-carinated dentition; high overall tooth count; and dorsolaterally inclined paroccipital processes), first appeared during the Middle Jurassic. Rhacheosaurins were curiously rare in the Middle Jurassic, as only one specimen of Maledictosuchus riclaensis is known (with no representatives discovered from the well-sampled Oxford Clay Formation of England). As such, the feeding/marine adaptations of Rhacheosaurini did not confer an immediate selective advantage upon the group, and it took until the Late Jurassic for this subclade to dominate in Western Europe.
Metriorhynchid crocodylomorphs were the only group of archosaurs to fully adapt to a pelagic lifestyle. During the Jurassic and Early Cretaceous, this group diversified into a variety of ecological and morphological types, from large super-predators with a broad short snout and serrated teeth to specialized piscivores/teuthophages with an elongate tubular snout and uncarinated teeth. Here, we use an integrated repertoire of geometric morphometric (form), biomechanical finite-element analysis (FEA; function) and phylogenetic data to examine the nature of craniofacial evolution in this clade. FEA stress values significantly correlate with morphometric values representing skull length and breadth, indicating that form and function are associated. Maximum-likelihood methods, which assess which of several models of evolution best explain the distribution of form and function data on a phylogenetic tree, show that the two major metriorhynchid subclades underwent different evolutionary modes. In geosaurines, both form and function are best explained as evolving under ‘random’ Brownian motion, whereas in metriorhynchines, the form metrics are best explained as evolving under stasis and the function metric as undergoing a directional change (towards most efficient low-stress piscivory). This suggests that the two subclades were under different selection pressures, and that metriorhynchines with similar skull shape were driven to become functionally divergent.
Metriorhynchidae; form; function; phenotypic evolution
The origin and evolutionary relationship of viruses is poorly understood. This makes archaeal virus-host systems of particular interest because the hosts generally root near the base of phylogenetic trees, while some of the viruses have clear structural similarities to those that infect prokaryotic and eukaryotic cells. Despite the advantageous position for use in evolutionary studies, little is known about archaeal viruses or how they interact with their hosts, compared to viruses of bacteria and eukaryotes. In addition, many archaeal viruses have been isolated from extreme environments and present a unique opportunity for elucidating factors that are important for existence at the extremes. In this article we focus on virus-host interactions using a proteomics approach to study Sulfolobus Turreted Icosahedral Virus (STIV) infection of Sulfolobus solfataricus P2. Using cultures grown from the ATCC cell stock, a single cycle of STIV infection was sampled six times over a 72 h period. More than 700 proteins were identified throughout the course of the experiments. Seventy one host proteins were found to change their concentration by nearly twofold (p < 0.05) with 40 becoming more abundant and 31 less abundant. The modulated proteins represent 30 different cell pathways and 14 clusters of orthologous groups. 2D gel analysis showed that changes in post-translational modifications were a common feature of the affected proteins. The results from these studies showed that the prokaryotic antiviral adaptive immune system CRISPR-associated proteins (CAS proteins) were regulated in response to the virus infection. It was found that regulated proteins come from mRNAs with a shorter than average half-life. In addition, activity-based protein profiling (ABPP) profiling on 2D-gels showed caspase, hydrolase, and tyrosine phosphatase enzyme activity labeling at the protein isoform level. Together, this data provides a more detailed global view of archaeal cellular responses to viral infection, demonstrates the power of quantitative two-dimensional differential gel electrophoresis and ABPP using 2D gel compatible fluorescent dyes.
archaea; virus infection; S. solfataricus P2; proteomics; virus–host interaction; differential gene expression; activity probes; caspase
This statement presents the latest evidence for integrated community case management of childhood illness, describes the necessary program elements and support tools for effective implementation, and lays out actions that countries and partners can take to support the implementation of integrated community case management at scale.
We describe community health workers (CHWs) in government community case management (CCM) programs for child survival across sub-Saharan Africa. In sub-Saharan Africa, 91% of 44 United Nations Children's Fund (UNICEF) offices responded to a cross-sectional survey in 2010. Frequencies describe CHW profiles and activities in government CCM programs (N = 29). Although a few programs paid CHWs a salary or conversely, rewarded CHWs purely on a non-financial basis, most programs combined financial and non-financial incentives and had training for 1 week. Not all programs allowed CHWs to provide zinc, use timers, dispense antibiotics, or use rapid diagnostic tests. Many CHWs undertake health promotion, but fewer CHWs provide soap, water treatment products, indoor residual spraying, or ready-to-use therapeutic foods. For newborn care, very few promote kangaroo care, and they do not provide antibiotics or resuscitation. Even if CHWs are as varied as the health systems in which they work, more work must be done in terms of the design and implementation of the CHW programs for them to realize their potential.
There are no known RNA viruses that infect Archaea. Filling this gap in our knowledge of viruses will enhance our understanding of the relationships between RNA viruses from the three domains of cellular life and, in particular, could shed light on the origin of the enormous diversity of RNA viruses infecting eukaryotes. We describe here the identification of novel RNA viral genome segments from high-temperature acidic hot springs in Yellowstone National Park in the United States. These hot springs harbor low-complexity cellular communities dominated by several species of hyperthermophilic Archaea. A viral metagenomics approach was taken to assemble segments of these RNA virus genomes from viral populations isolated directly from hot spring samples. Analysis of these RNA metagenomes demonstrated unique gene content that is not generally related to known RNA viruses of Bacteria and Eukarya. However, genes for RNA-dependent RNA polymerase (RdRp), a hallmark of positive-strand RNA viruses, were identified in two contigs. One of these contigs is approximately 5,600 nucleotides in length and encodes a polyprotein that also contains a region homologous to the capsid protein of nodaviruses, tetraviruses, and birnaviruses. Phylogenetic analyses of the RdRps encoded in these contigs indicate that the putative archaeal viruses form a unique group that is distinct from the RdRps of RNA viruses of Eukarya and Bacteria. Collectively, our findings suggest the existence of novel positive-strand RNA viruses that probably replicate in hyperthermophilic archaeal hosts and are highly divergent from RNA viruses that infect eukaryotes and even more distant from known bacterial RNA viruses. These positive-strand RNA viruses might be direct ancestors of RNA viruses of eukaryotes.
A 67-years-old male presented with periumbilical abdominal pain, fever and jaundice. His anaerobic blood culture was positive for clostridium perfringens. Computed tomogram scan of the abdomen and abdominal ultrasound showed normal gallbladder and common bile duct (CBD). Subsequently magnetic resonance cholangiopancreaticogram showed choledocholithiasis. Endoscopic retrograde cholangiopancreaticogramwith sphincterotomy and CBD stone extraction was performed. The patient progressively improved with antibiotic therapy Choledocholithiasis should be considered as a source of clostridium perfringens bacteremia especially in the setting of elevated liver enzymes with cholestatic pattern.
Choledocholithiasis; Clostridium perfringens; Bacteremia
Dakosaurus and Plesiosuchus are characteristic genera of aquatic, large-bodied, macrophagous metriorhynchid crocodylomorphs. Recent studies show that these genera were apex predators in marine ecosystems during the latter part of the Late Jurassic, with robust skulls and strong bite forces optimized for feeding on large prey.
Here we present comprehensive osteological descriptions and systematic revisions of the type species of both genera, and in doing so we resurrect the genus Plesiosuchus for the species Dakosaurus manselii. Both species are diagnosed with numerous autapomorphies. Dakosaurus maximus has premaxillary ‘lateral plates’; strongly ornamented maxillae; macroziphodont dentition; tightly fitting tooth-to-tooth occlusion; and extensive macrowear on the mesial and distal margins. Plesiosuchus manselii is distinct in having: non-amblygnathous rostrum; long mandibular symphysis; microziphodont teeth; tooth-crown apices that lack spalled surfaces or breaks; and no evidence for occlusal wear facets. Our phylogenetic analysis finds Dakosaurus maximus to be the sister taxon of the South American Dakosaurus andiniensis, and Plesiosuchus manselii in a polytomy at the base of Geosaurini (the subclade of macrophagous metriorhynchids that includes Dakosaurus, Geosaurus and Torvoneustes).
The sympatry of Dakosaurus and Plesiosuchus is curiously similar to North Atlantic killer whales, which have one larger ‘type’ that lacks tooth-crown breakage being sympatric with a smaller ‘type’ that has extensive crown breakage. Assuming this morphofunctional complex is indicative of diet, then Plesiosuchus would be a specialist feeding on other marine reptiles while Dakosaurus would be a generalist and possible suction-feeder. This hypothesis is supported by Plesiosuchus manselii having a very large optimum gape (gape at which multiple teeth come into contact with a prey-item), while Dakosaurus maximus possesses craniomandibular characteristics observed in extant suction-feeding odontocetes: shortened tooth-row, amblygnathous rostrum and a very short mandibular symphysis. We hypothesise that trophic specialisation enabled these two large-bodied species to coexist in the same ecosystem.
A factor contributing to the pathogenicity of Bacteroides fragilis, the most common anaerobic species isolated from clinical infections, is the bacterium's extreme aerotolerance, which allows survival in oxygenated tissues prior to anaerobic abscess formation. We investigated the role of the bacterioferritin-related (bfr) gene in the B. fragilis oxidative stress response. The bfr mRNA levels are increased in stationary phase or in response to O2 or iron. In addition, bfr null mutants exhibit reduced aerotolerance, and the bfr gene product protects DNA from hydroxyl radical cleavage in vitro. Crystallographic studies revealed a protein with a dodecameric structure and greater similarity to an archaeal DNA protection in starved cells (DPS)-like protein than to the 24-subunit bacterioferritins. Similarity to the DPS-like (DPSL) protein extends to the subunit and includes a pair of conserved cysteine residues juxtaposed to a buried dimetal binding site within the four-helix bundle. Compared to archaeal DPSLs, however, this bacterial DPSL protein contains several unique features, including a significantly different conformation in the C-terminal tail that alters the number and location of pores leading to the central cavity and a conserved metal binding site on the interior surface of the dodecamer. Combined, these characteristics confirm this new class of miniferritin in the bacterial domain, delineate the similarities and differences between bacterial DPSL proteins and their archaeal homologs, allow corrected annotations for B. fragilis bfr and other dpsl genes within the bacterial domain, and suggest an evolutionary link within the ferritin superfamily that connects dodecameric DPS to the (bacterio)ferritin 24-mer.
Cage-like protein nano particles are promising platforms for cell and tissue specific targeted delivery of imaging and therapeutic agents. Here, we have successfully modified the 12 nm small heat shock protein from Methanococcus jannaschii (MjHsp) to detect atherosclerotic plaque lesions in a mouse model system. As macrophages are centrally involved in the initiation and progression of atherosclerosis, targeted imaging of macrophages is valuable to assess the biologic status of the blood vessel wall. LyP-1, a nine residue peptide, has been shown to target tumor-associated macrophages. Thus, LyP-1 was genetically incorporated onto the exterior surface of MjHsp, while a fluorescent molecule (Cy5.5) was conjugated on the interior cavity. This bioengineered protein cage, LyP-Hsp, exhibited enhanced affinity to macrophage in vitro. Furthermore, in vivo injection of LyP-Hsp allowed visualization of macrophage-rich murine carotid lesions by in situ and ex vivo fluorescence imaging. These results demonstrate the potential of LyP-1-conjugated protein cages as nano-scale platforms for delivery of imaging agents for the diagnosis of atherosclerosis.
protein cage; nanoparticle; imaging agent; atherosclerosis; macrophage; cell specific targeting
Atherosclerosis is a leading cause of death worldwide. Macrophages are key components of vascular inflammation, which contributes to the development and complications of atherosclerosis. Ferritin, an iron storage and transport protein, has been found to accumulate in macrophages in human atherosclerotic plaques. We hypothesized that ferritin could serve as an intrinsic nano-platform to target delivery of imaging agents to vascular macrophages to detect high-risk atherosclerotic plaques. Here we show that engineered human ferritin protein cages, either conjugated to the fluorescent Cy5.5 molecule or encapsulating a magnetite nanoparticle, are taken up in vivo by macrophages in murine atherosclerotic carotid arteries and can be imaged by fluorescence and magnetic resonance imaging. These results indicate that human ferritin can serve as a nanoparticle platform to image vascular inflammation in vivo.
nanoparticle; inflammation; macrophage; ferritin; atherosclerosis; molecular imaging
Tendon injuries are a common cause of morbidity and a significant health burden on society. Tendons are structural tissues connecting muscle to bone and are prone to tearing and tendinopathy, an overuse or degenerative condition that is characterized by failed healing and cellular depletion. Current treatments, for tendon tear are conservative, surgical repair or surgical scaffold reconstruction. Tendinopathy is treated by exercises, injection therapies, shock wave treatments or surgical tendon debridement. However, tendons usually heal with fibrosis and scar tissue, which has suboptimal tensile strength and is prone to reinjury, resulting in lifestyle changes with activity restriction. Preclinical studies show that cell therapies have the potential to regenerate rather than repair tendon tissue, a process termed tenogenesis. A number of different cell lines, with varying degrees of differentiation, have being evaluated including stem cells, tendon derived cells and dermal fibroblasts. Even though cellular therapies offer some potential in treating tendon disorders, there have been few published clinical trials to determine the ideal cell source, the number of cells to administer, or the optimal bioscaffold for clinical use.
The transversus abdominis plane (TAP) block is a relatively new regional anesthesia technique that provides analgesia to the parietal peritoneum as well as the skin and muscles of the anterior abdominal wall. It has a high margin of safety and is technically simple to perform, especially under ultrasound guidance. A growing body of evidence supports the use of TAP blocks for a variety of abdominal procedures, yet, widespread adoption of this therapeutic adjunct has been slow. In part, this may be related to the limited sources for anesthesiologists to develop an appreciation for its sound anatomical basis and the versatility of its clinical application. As such, we provide a brief historical perspective on the TAP block, describe relevant anatomy, review current techniques, discuss pharmacologic considerations, and summarize the existing literature regarding its clinical utility with an emphasis on recently published studies that have not been included in other systematic reviews or meta-analyses.
Host cells infected by Sulfolobus turreted icosahedral virus (STIV) have been shown to produce unusual pyramid-like structures on the cell surface. These structures represent a virus-induced lysis mechanism that is present in Archaea and appears to be distinct from the holin/endolysin system described for DNA bacteriophages. This study investigated the STIV gene products required for pyramid formation in its host Sulfolobus solfataricus. Overexpression of STIV open reading frame (ORF) c92 in S. solfataricus alone is sufficient to produce the pyramid-like lysis structures in cells. Gene disruption of c92 within STIV demonstrates that c92 is an essential protein for virus replication. Immunolocalization of c92 shows that the protein is localized to the cellular membranes forming the pyramid-like structures.
We applied whole cell electron cryotomography to the archaeon Sulfolobus infected by Sulfolobus turreted icosahedral virus (STIV), which belongs to the PRD1-Adeno lineage of dsDNA viruses. STIV infection induced the formation of pyramid-like protrusions with sharply defined facets on the cell surface. They had a thicker cross-section than the cytoplasmic membrane and did not contain an exterior surface protein layer (S-layer). Intra-pyramidal bodies often occupied the volume of the pyramids. Mature virions, procapsids without genome cores, and partially assembled particles were identified, suggesting that the capsid and inner membrane co-assemble in the cytoplasm to form a procapsid. A two-class reconstruction using a maximum likelihood algorithm demonstrated that no dramatic capsid transformation occurred upon DNA packaging. Virions tended to form tightly packed clusters or quasi-crystalline arrays while procapsids mostly scattered outside or on the edges of the clusters. The study revealed vivid images of STIV assembly, maturation and particle distribution in cell.
Electron cryotomography (ECT); Sulfolobus turreted icosahedral virus (STIV); in vivo virus assembly; Sulfolobus; inner-membrane containing viruses