Translocation (11;14) is a common cytogenetic abnormality in clonal plasma cells in monoclonal immunoglobulin deposition disease.

Monoclonal Immunoglobulin deposition disease (MIDD) is characterised by deposits of intact monoclonal light chains in the kidney leading to renal dysfunction. In this study, we retrospectively investigated the underlying plasma cell cytogenetic abnormalities in MIDD. CyclinD1 (11;14) translocation was identified in 12/27 (45%) patients. Among the patients without translocation, del13q and hyperdiploidy were the most common abnormalities. Patients in the non-t (11;14) group had a higher baseline light-chain ratio, higher proteinuria and lower eGFR as compared to patients with t (11;14). Haematological VGPR or higher was seen in 58% of t (11;14), and 30% without t (11;14), possibly related to higher use of Daratumumab-based therapy in the t (11;14) group. With a median follow-up of 750 days, 30% (8/24) progressed to end stage renal disease (ESRD). eGFR <20 mL/min (HR 25, 95% CI 2.09-298, p = 0.01) and 24 urine protein >3 g/24 h (HR 9, 95% CI 1.27-63.90, p = 0.02) at diagnosis were significantly associated with progression to ESRD. Renal survival was better in t (11;14) as compared to the non-t (11;14) group (HR 0.11, p = 0.06). Translocation (11;14) is a common abnormality in MIDD and affects the presentation and outcomes. Identification of this abnormality should lead to exploration of BCL2 inhibitors in this disease.

Copper Isotope Compositions Measured Using a Sapphire Dual Path MC-ICPMS with a Collision/Reaction Cell.

We present a new approach to Cu isotopic measurements using a state-of-the-art Nu Sapphire multicollector inductively coupled plasma source mass spectrometer equipped with a collision/reaction cell (CRC-MC-ICPMS). We investigate the effects of Na doping and Cu concentration mismatch between bracketing standard and unknown samples and demonstrate the efficacy of introducing a He-H2 gas mix into the CRC to efficiently eliminate the sample matrix-based 40Ar23Na+ isobaric interference on 63Cu+. This capability is crucial when measuring samples with high Na/Cu ratios, such as some biological samples, which have significantly different chemical compositions compared to most geological samples. Moreover, considering the necessity of obtaining large data sets for biological samples to ensure reliable interpretations, the implementation of a CRC for mitigating the 40Ar23Na+ interference offers the advantage of minimizing the requirement for extensive Cu chemical separation procedure prior to Cu isotopic measurements. Our results demonstrate that the accurate determination of the δ65Cu values is achievable for samples with Na/Cu concentration ratios of up to ∼65, even when measuring 100 ppb Cu solutions (equivalent to a signal of ∼3.5-4 V total Cu). Furthermore, our results showcase a good short-term repeatability on δ65Cu for pure Cu standard solutions (NIST SRM 976 and Cu-IPGP), typically of 0.05‰ (2 SD) when measuring >50 ppb Cu solutions. Our long-term external reproducibility stands at approximately 0.07‰ (2 SD). This value accounts for the variable Cu concentrations analyzed across the different analytical sequences (from 10 to 100 ppb Cu solutions). To validate the robustness of our analytical method, we first conduct a comparison between data sets from mice brains processed twice through column chemistry using a Thermo Finnigan Neptune MC-ICPMS and a Nu Sapphire CRC-MC-ICPMS in CRC mode. This comparison serves to verify the reliability of our method for measuring Cu isotopic composition using the CRC on samples with a low Na/Cu ratio after traditional chemical processing. Then, we compare the data sets obtained for biological standards (tuna fish ERM-CE 464 (IRMM) and human serum Seronorm Trace Elements Serum L-1) processed either once, or twice, through column chemistry and demonstrate that the CRC allows accurate Cu isotopic measurements of the samples processed only once and therefore with a higher Na/Cu ratio.

Unraveling the molecular determinants of the anti-phagocytic protein cloak of plague bacteria.

The pathogenic bacterium Yersina pestis is protected from macrophage engulfment by a capsule like antigen, F1, formed of long polymers of the monomer protein, Caf1. However, despite the importance of this pathogen, the mechanism of protection was not understood. Here we demonstrate how F1 protects the bacteria from phagocytosis. First, we show that Escherichia coli expressing F1 showed greatly reduced adherence to macrophages. Furthermore, the few cells that did adhere remained on the macrophage surface and were not engulfed. We then inserted, by mutation, an "RGDS" integrin binding motif into Caf1. This did not change the number of cells adhering to macrophages but increased the fraction of adherent cells that were engulfed. Therefore, F1 protects in two separate ways, reducing cell adhesion, possibly by acting as a polymer brush, and hiding innate receptor binding sites needed for engulfment. F1 is very robust and we show that E. coli expressing weakened mutant polymers are engulfed like the RGDS mutant. This suggests that innate attachment sites on the native cell surface are exposed if F1 is weakened. Single-molecule force spectroscopy (SMFS) experiments revealed that wild-type F1 displays a very high mechanical stability of 400 pN. However, the mechanical resistance of the destabilised mutants, that were fully engulfed, was only 20% weaker. By only marginally exceeding the mechanical force applied to the Caf1 polymer during phagocytosis it may be that the exceptional tensile strength evolved to resist the forces applied at this stage of engulfment.

A Managed Care System with Telemedicine Support for Neurological Emergencies.

OBJECTIVES: Telemedicine is frequently used to provide remote neurological expertise for acute stroke workup and was associated with better functional outcomes when combined with a stroke unit system-of-care. We investigated whether such system-of-care yields additional benefits when implemented on top of neurological competence already available onsite. METHODS: Quality improvement measures were implemented within a "hub-and-spoke" teleneurology network in 11 hospitals already provided with onsite or telestroke expertise. Measures included dedicated units for neurological emergencies, standardization of procedures, multiprofessional training, and quality-of-care monitoring. Intervention effects were investigated in a controlled study enrolling patients insured at 3 participating statutory health insurances diagnosed with acute stroke or other neurological emergencies. Outcomes during the intervention period between November 2017 and February 2020 were compared with those pre-intervention between October 2014 and March 2017. To control for temporal trends, we compared outcomes of patients with respective diagnoses in 11 hospitals of the same region. Primary outcome was the composite of up-to-90-day death, new disability with the need of ambulatory or nursing home care, expressed by adjusted hazard ratio (aHR). RESULTS: We included 1,418 patients post-implementation (55% female, mean age 76.7 ± 12.8 year) and 2,306 patients pre-implementation (56%, 75.8 ± 13.0 year, respectively). The primary outcome occurred in 479/1,418 (33.8%) patients post-implementation and in 829/2,306 (35.9%) pre-implementation. The aHR for the primary outcome was 0.89 (95% confidence interval [CI]: 0.79-0.99, p = 0.04) with no improvement seen in non-participating hospitals between post- versus pre-implementation periods (aHR 1.04; 95% CI: 0.95-1.15). INTERPRETATION: Implementation of a multicomponent system-of-care was associated with a lower risk of poor outcomes. ANN NEUROL 2023;93:511-521.

Identifying Patterns and Sources of Fine and Ultrafine Particulate Matter in London Using Mobile Measurements of Lung-Deposited Surface Area.

We performed more than a year of mobile, 1 Hz measurements of lung-deposited surface area (LDSA, the surface area of 20-400 nm diameter particles, deposited in alveolar regions of lungs) and optically assessed fine particulate matter (PM2.5), black carbon (BC), and nitrogen dioxide (NO2) in central London. We spatially correlated these pollutants to two urban emission sources: major roadways and restaurants. We show that optical PM2.5 is an ineffective indicator of tailpipe emissions on major roadways, where we do observe statistically higher LDSA, BC, and NO2. Additionally, we find pollutant hot spots in commercial neighborhoods with more restaurants. A low LDSA (15 µm2 cm-3) occurs in areas with fewer major roadways and restaurants, while the highest LDSA (25 µm2 cm-3) occurs in areas with more of both sources. By isolating areas that are higher in one source than the other, we demonstrate the comparable impacts of traffic and restaurants on LDSA. Ratios of hyperlocal enhancements (ΔLDSA:ΔBC and ΔLDSA:ΔNO2) are higher in commercial neighborhoods than on major roadways, further demonstrating the influence of restaurant emissions on LDSA. We demonstrate the added value of using particle surface in identifying hyperlocal patterns of health-relevant PM components, especially in areas with strong vehicular emissions where the high LDSA does not translate to high PM2.5.

DNA metabarcoding reveals metacommunity dynamics in a threatened boreal wetland wilderness.

The complexity and natural variability of ecosystems present a challenge for reliable detection of change due to anthropogenic influences. This issue is exacerbated by necessary trade-offs that reduce the quality and resolution of survey data for assessments at large scales. The Peace-Athabasca Delta (PAD) is a large inland wetland complex in northern Alberta, Canada. Despite its geographic isolation, the PAD is threatened by encroachment of oil sands mining in the Athabasca watershed and hydroelectric dams in the Peace watershed. Methods capable of reliably detecting changes in ecosystem health are needed to evaluate and manage risks. Between 2011 and 2016, aquatic macroinvertebrates were sampled across a gradient of wetland flood frequency, applying both microscope-based morphological identification and DNA metabarcoding. By using multispecies occupancy models, we demonstrate that DNA metabarcoding detected a much broader range of taxa and more taxa per sample compared to traditional morphological identification and was essential to identifying significant responses to flood and thermal regimes. We show that family-level occupancy masks high variation among genera and quantify the bias of barcoding primers on the probability of detection in a natural community. Interestingly, patterns of community assembly were nearly random, suggesting a strong role of stochasticity in the dynamics of the metacommunity. This variability seriously compromises effective monitoring at local scales but also reflects resilience to hydrological and thermal variability. Nevertheless, simulations showed the greater efficiency of metabarcoding, particularly at a finer taxonomic resolution, provided the statistical power needed to detect change at the landscape scale.

Products Generated by Amine-Catalyzed Strand Cleavage at Apurinic/Apyrimidinic Sites in DNA: New Insights from a Biomimetic Nucleoside Model System.

Abasic sites are common in cellular and synthetic DNA. As a result, it is important to characterize the chemical fate of these lesions. Amine-catalyzed strand cleavage at abasic sites in DNA is an important process in which conversion of small amounts of the ring-opened abasic aldehyde residue to an iminium ion facilitates ß-elimination of the 3'-phosphoryl group. This reaction generates a trans-α,ß-unsaturated iminium ion on the 3'-terminus of the strand break as an obligate intermediate. The canonical product expected from amine-catalyzed cleavage at an AP site is the corresponding trans-α,ß-unsaturated aldehyde sugar remnant resulting from hydrolysis of this iminium ion. Interestingly, a handful of studies have reported noncanonical 3'-sugar remnants generated by amine-catalyzed strand cleavage, but the formation and properties of these products are not well-understood. To address this knowledge gap, a nucleoside system was developed that enabled chemical characterization of the sugar remnants generated by amine-catalyzed ß-elimination in the 2-deoxyribose system. The results predict that amine-catalyzed strand cleavage at an AP site under physiological conditions has the potential to reversibly generate noncanonical cleavage products including cis-alkenal, 3-thio-2,3-dideoxyribose, and 2-deoxyribose groups alongside the canonical trans-alkenal residue on the 3'-terminus of the strand break. Thus, the model reactions provide evidence that the products generated by amine-catalyzed strand cleavage at abasic sites in cellular DNA may be more complex that commonly thought, with trans-α,ß-unsaturated iminium ion intermediates residing at the hub of interconverting product mixtures. The results expand the list of possible 3'-sugar remnants arising from amine-catalyzed cleavage of abasic sites in DNA that must be chemically or enzymatically removed for the completion of base excision repair and single-strand break repair in cells.

Spatial-Controlled Coating of Pro-Angiogenic Proteins on 3D Porous Hydrogels Guides Endothelial Cell Behavior.

In tissue engineering, the composition and the structural arrangement of molecular components within the extracellular matrix (ECM) determine the physical and biochemical features of a scaffold, which consequently modulate cell behavior and function. The microenvironment of the ECM plays a fundamental role in regulating angiogenesis. Numerous strategies in tissue engineering have attempted to control the spatial cues mimicking in vivo angiogenesis by using simplified systems. The aim of this study was to develop 3D porous crosslinked hydrogels with different spatial presentation of pro-angiogenic molecules to guide endothelial cell (EC) behavior. Hydrogels with pores and preformed microchannels were made with pharmaceutical-grade pullulan and dextran and functionalized with novel pro-angiogenic protein polymers (Caf1-YIGSR and Caf1-VEGF). Hydrogel functionalization was achieved by electrostatic interactions via incorporation of diethylaminoethyl (DEAE)-dextran. Spatial-controlled coating of hydrogels was realized through a combination of freeze-drying and physical absorption with Caf1 molecules. Cells in functionalized scaffolds survived, adhered, and proliferated over seven days. When incorporated alone, Caf1-YIGSR mainly induced cell adhesion and proliferation, whereas Caf1-VEGF promoted cell migration and sprouting. Most importantly, directed cell migration required the presence of both proteins in the microchannel and in the pores, highlighting the need for an adhesive substrate provided by Caf1-YIGSR for Caf1-VEGF to be effective. This study demonstrates the ability to guide EC behavior through spatial control of pro-angiogenic cues for the study of pro-angiogenic signals in 3D and to develop pro-angiogenic implantable materials.

Probing the oligomeric re-assembling of bacterial fimbriae in vitro: a small-angle X-ray scattering and analytical ultracentrifugation study.

Capsular antigen fragment 1 (Caf1) is an oligomeric protein consisting of 15 kDa monomeric subunits that are non-covalently linked through exceptionally strong and kinetically inert interactions into a linear polymer chain. It has been shown that after its thermal depolymerisation into unfolded monomeric subunits, Caf1 is able to efficiently repolymerise in vitro to reform its polymeric structure. However, little is known about the nature of the repolymerisation process. An improved understanding of this process will lead to the development of methods to better control the lengths of the repolymerised species, and ultimately, to better design of the properties of Caf1-based materials. Here we utilize small-angle X-ray scattering to estimate the size of Caf1 polymers during the first 24 h of the re-polymerisation process. Analytical ultracentrifugation measurements were also used to investigate the process post-24 h, where the rate of repolymerisation becomes considerably slower. Results show that in vitro polymerisation proceeds in a linear manner with no evidence observed for the formation of a lateral polymer network or uncontrolled aggregates. The rate of Caf1 in vitro repolymerisation was found to be concentration-dependent. Importantly, the rate of polymer growth was found to be relatively fast over the first few hours, before continuing at a dramatically slower rate. This observation is not consistent with the previously proposed step-growth mechanism of in vitro polymerisation of Caf1, where a linear increase in polymer length would be expected with time. We speculate how our observations may support the idea that the polymerisation process may be occurring at the ends of the chains with monomers adding sequentially. Our findings will contribute towards the development of new biomaterials for 3D cell culture and bio-printing.

When Measurements Meet Blockchain: On Behalf of an Inter-NMI Network.

The growing demand for solutions related to measurement (e.g., digital sensors, smart meters, distributed measuring systems) imposes several concerns about information and process reliability. In this context, blockchain can play a crucial role as a platform to implement applications and activities in the context of legal metrology. In most countries, the National Metrology Institutes (NMIs) are responsible for promoting these initiatives. Thus, in this paper, we present a functional architecture to integrate NMIs in a collaborative blockchain network. We discuss the main aspects and features that an inter-NMI blockchain network must deliver. Furthermore, we implement our proposal using the Hyperledger Fabric platform. We connect peers from Physikalisch-Technische Bundesanstalt (PTB) (German NMI) and the National Institute of Metrology, Quality, and Technology (Inmetro) (Brazilian NMI) in a useful application that consists of a blockchain-based public-key infrastructure to identify and authenticate smart meters. Our preliminary results demonstrate that the proposed architecture meets the main requirements imposed by applications involving measurements. Furthermore, it opens the opportunity to integrate NMIs from other countries into the project, constituting an important global initiative in the metrology field.

Intradiploic Hematoma Associated With Synostosis in an Infant.

Intradiploic hematomas are extremely rare, particularly in newborns. Caused by bleeding between the inner and outer tables of the calvarium, they manifest with bony swelling of the skull. The authors present the first case of an intraosseous hematoma associated with synostosis, and the first report in a female patient. The clinical, radiological, surgical, and pathological characteristics of this lesion are discussed.

Induction of the immunoprotective coat of Yersinia pestis at body temperature is mediated by the Caf1R transcription factor.

BACKGROUND: Thermal regulation of gene expression occurs in many microorganisms, and is mediated via several typical mechanisms. Yersinia pestis is the causative agent of the plague and spreads by zoonotic transfer from fleas to mammalian blood with a concomitant rapid temperature change, from ambient to 37 °C, which induces the expression of capsular antigen (Caf1) that inhibits phagocytosis. Caf1 is formed into long polymeric fimbriae by a periplasmic chaperone (Caf1M) and outer membrane usher (Caf1A). All three are encoded on an operon regulated by an AraC-type transcription factor Caf1R. The aim of this study was to determine the role of Caf1R in the thermal control of caf1 operon gene expression. RESULTS: PCR analysis of cDNA demonstrated that the genes of the operon are transcribed as a single polycistronic mRNA. Bioinformatic analysis, supported by deletion mutagenesis, then revealed a region containing the promoter of this polycistronic transcript that was critical for Caf1 protein expression. Caf1R was found to be essential for Caf1 protein production. Finally, RT-PCR analysis and western blot experiments showed large, Caf1R dependent increases in caf1 operon transcripts upon a shift in temperature from 25 °C to 35 °C. CONCLUSIONS: The results show that thermal control of Caf1 polymer production is established at the transcriptional level, in a Caf1R dependent manner. This gives us new insights into how a virulent pathogen evades destruction by the immune system by detecting and responding to environmental changes.

Resveratrol-Coated Balloon Catheters in Porcine Coronary and Peripheral Arteries.

Angioplasty aiming at vascular dilatation causes endothelial denudation and induces complex inflammatory responses that affect vascular healing, including delayed reendothelialization and excessive neointima proliferation. Resveratrol is known for multiple beneficial effects on the vessel wall after systemic treatment or sustained release from a stent. It is also used as an additive on drug-coated balloon catheters (DCB). In this study, the effect of a single dose of resveratrol, three days to four weeks after administration as a balloon coating during angioplasty, was investigated. Sixteen pigs underwent angioplasty with resveratrol-coated or uncoated balloon catheters in coronary and peripheral arteries. Vessels were overstretched by approximately 20% to enhance vessel wall injury and to produce persistent vessel wall irritation. A significantly reduced number of micro vessels and macrophages in the adventitia, as well as an improved reendothelialization of the vessel lumen, were observed in resveratrol-treated peripheral arteries. The coronaries had a much higher injury score compared to peripheral vessels. Resveratrol-dependent reduction of macrophages, micro vessels or acceleration of reendothelialization was not evident in the coronary vessels. Additionally, no significant effect on neointima proliferation and inflammation score in either vessel territory was observed as a result of resveratrol treatment. In conclusion, the results suggest that resveratrol diminishes the inflammatory response and promotes vascular healing in peripheral arteries. These same effects are absent in more severely injured coronary arteries.

A systematic review of the human health and social well-being outcomes of green infrastructure for stormwater and flood management.

BACKGROUND: The increase in frequency and intensity of urban flooding is a global challenge. Flooding directly impacts residents of industrialized cities with aging combined sewer systems, as well as cities with less centralized infrastructure to manage stormwater, fecal sludge, and wastewater. Green infrastructure is growing in popularity as a sustainable strategy to mimic nature-based flood management. Although its technical performance has been extensively studied, little is known about the effects of green stormwater infrastructure on human health and social well-being. METHODS: We conducted a multidisciplinary systematic review of peer-reviewed and gray literature on the effects of green infrastructure for stormwater and flood management on individuals', households', and communities' a) physical health; b) mental health; c) economic well-being; and d) flood resilience and social acceptance of green infrastructure. We systematically searched databases such as PubMed, Web of Science, and Scopus; the first 300 results in Google Scholar; and websites of key organizations including the United States Environmental Protection Agency. Study quality and strength of evidence was assessed for included studies, and descriptive data were extracted for a narrative summary. RESULTS: Out of 21,213 initial results, only 18 studies reported health or social well-being outcomes. Seven of these studies used primary data, and none allowed for causal inference. No studies connected green infrastructure for stormwater and flood management to mental or physical health outcomes. Thirteen studies were identified on economic outcomes, largely reporting a positive association between green infrastructure and property values. Five studies assessed changes in perceptions about green infrastructure, but with mixed results. Nearly half of all included studies were from Portland, Oregon. CONCLUSIONS: This global systematic review highlights the minimal evidence on human health and social well-being relating to green infrastructure for stormwater and flood management. To enable scale-up of this type of infrastructure to reduce flooding and improve ecological and human well-being, widespread acceptance of green infrastructure will be essential. Policymakers and planners need evidence on the full range of benefits from different contexts to enable financing and implementation of instfrastructure options, especially in highly urbanized, flood-prone settings around the world. Therefore, experts in social science, public health, and program evaluation must be integrated into interdisciplinary green infrastructure research to better relate infrastructure design to tangible human outcomes.

Major reorientation of tRNA substrates defines specificity of dihydrouridine synthases.

The reduction of specific uridines to dihydrouridine is one of the most common modifications in tRNA. Increased levels of the dihydrouridine modification are associated with cancer. Dihydrouridine synthases (Dus) from different subfamilies selectively reduce distinct uridines, located at spatially unique positions of folded tRNA, into dihydrouridine. Because the catalytic center of all Dus enzymes is conserved, it is unclear how the same protein fold can be reprogrammed to ensure that nucleotides exposed at spatially distinct faces of tRNA can be accommodated in the same active site. We show that the Escherichia coli DusC is specific toward U16 of tRNA. Unexpectedly, crystal structures of DusC complexes with tRNA(Phe) and tRNA(Trp) show that Dus subfamilies that selectively modify U16 or U20 in tRNA adopt identical folds but bind their respective tRNA substrates in an almost reverse orientation that differs by a 160° rotation. The tRNA docking orientation appears to be guided by subfamily-specific clusters of amino acids ("binding signatures") together with differences in the shape of the positively charged tRNA-binding surfaces. tRNA orientations are further constrained by positional differences between the C-terminal "recognition" domains. The exquisite substrate specificity of Dus enzymes is therefore controlled by a relatively simple mechanism involving major reorientation of the whole tRNA molecule. Such reprogramming of the enzymatic specificity appears to be a unique evolutionary solution for altering tRNA recognition by the same protein fold.

Human Miro Proteins Act as NTP Hydrolases through a Novel, Non-Canonical Catalytic Mechanism.

Mitochondria are highly dynamic organelles that play a central role in multiple cellular processes, including energy metabolism, calcium homeostasis and apoptosis. Miro proteins (Miros) are "atypical" Ras superfamily GTPases that display unique domain architecture and subcellular localisation regulating mitochondrial transport, autophagy and calcium sensing. Here, we present systematic catalytic domain characterisation and structural analyses of human Miros. Despite lacking key conserved catalytic residues (equivalent to Ras Y32, T35, G60 and Q61), the Miro N-terminal GTPase domains display GTPase activity. Surprisingly, the C-terminal GTPase domains previously assumed to be "relic" domains were also active. Moreover, Miros show substrate promiscuity and function as NTPases. Molecular docking and structural analyses of Miros revealed unusual features in the Switch I and II regions, facilitating promiscuous substrate binding and suggesting the usage of a novel hydrolytic mechanism. The key substitution in position 13 in the Miros leads us to suggest the existence of an "internal arginine finger", allowing an unusual catalytic mechanism that does not require GAP protein. Together, the data presented here indicate novel catalytic functions of human Miro atypical GTPases through altered catalytic mechanisms.

Anomalous Extratemporal Facial Nerve in Oculoauriculovertebral Spectrum.

Facial nerve dysfunction is common in oculoauriculovertebral spectrum (OAVS). However, the course of the nerve has rarely been described. A 23-year-old woman with OAVS underwent excision of microtic ear remnants in preparation for an osseointegrated prosthesis and suffered iatrogenic transection of the facial nerve-the pes anserinus was within the subcutaneous tissue 15 mm posterior and 15 mm cephalad to the external acoustic meatus. The patient underwent primary nerve repair and regained nearly complete preoperative function. When considering reconstruction for OAVS patients, clinicians should have a high index of suspicion for anomalous facial nerve anatomy.

lin28 proteins promote expression of 17∼92 family miRNAs during amphibian development.

BACKGROUND: Lin28 proteins are post-transcriptional regulators of gene expression with multiple roles in development and the regulation of pluripotency in stem cells. Much attention has focussed on Lin28 proteins as negative regulators of let-7 miRNA biogenesis; a function that is conserved in several animal groups and in multiple processes. However, there is increasing evidence that Lin28 proteins have additional roles, distinct from regulation of let-7 abundance. We have previously demonstrated that lin28 proteins have functions associated with the regulation of early cell lineage specification in Xenopus embryos, independent of a lin28/let-7 regulatory axis. However, the nature of lin28 targets in Xenopus development remains obscure. RESULTS: Here, we show that mir-17∼92 and mir-106∼363 cluster miRNAs are down-regulated in response to lin28 knockdown, and RNAs from these clusters are co-expressed with lin28 genes during germ layer specification. Mature miRNAs derived from pre-mir-363 are most sensitive to lin28 inhibition. We demonstrate that lin28a binds to the terminal loop of pre-mir-363 with an affinity similar to that of let-7, and that this high affinity interaction requires to conserved a GGAG motif. CONCLUSIONS: Our data suggest a novel function for amphibian lin28 proteins as positive regulators of mir-17∼92 family miRNAs.

Human Lin28 Forms a High-Affinity 1:1 Complex with the 106~363 Cluster miRNA miR-363.

Lin28A is a post-transcriptional regulator of gene expression that interacts with and negatively regulates the biogenesis of let-7 family miRNAs. Recent data suggested that Lin28A also binds the putative tumor suppressor miR-363, a member of the 106~363 cluster of miRNAs. Affinity for this miRNA and the stoichiometry of the protein-RNA complex are unknown. Characterization of human Lin28's interaction with RNA has been complicated by difficulties in producing stable RNA-free protein. We have engineered a maltose binding protein fusion with Lin28, which binds let-7 miRNA with a Kd of 54.1 ± 4.2 nM, in agreement with previous data on a murine homologue. We show that human Lin28A binds miR-363 with a 1:1 stoichiometry and with a similar, if not higher, affinity (Kd = 16.6 ± 1.9 nM). Further analysis suggests that the interaction of the N-terminal cold shock domain of Lin28A with RNA is salt-dependent, supporting a model in which the cold shock domain allows the protein to sample RNA substrates through transient electrostatic interactions.

Retrieving the real refractive index of mono- and polydisperse colloids from reflectance near the critical angle.

We investigate the accuracy in retrieving the real refractive index of submicron aerosol particles, at a visible wavelength, from near critical angle reflectance measurements of a dilute suspension of the aerosol. A coherent scattering model (CSM) is used to model the coherent reflectance from the colloidal suspension. We use an extension of the model for polydisperse particles to properly account for the modified size distribution close to the incident medium to colloid interface. We perform a rigorous sensitivity analysis, for both the monodisperse and polydisperse models, to determine how experimental uncertainties propagate into uncertainty in the retrieval of real refractive index. The effect of non-spherical scattering was included in the sensitivity analysis by using T-matrix methods. Experimental reflectance data, at a wavelength of 635 nm, were obtained for monodisperse spherical latex particles, a polydisperse sand sample and a polydisperse volcanic ash sample. We show that the retrieved real refractive index for these particles is consistent with values obtained using other techniques.