bluuebunny/crossref_metadata_2025 huggingface dataset:
Erbium Yttrium–Aluminum–Garnet Laser Versus Traditional Bur in the Extraction of Impacted Mandibular Third Molars: Analysis of Intra- and Postoperative Differences
Authors: Giovannacci Ilaria , Giunta Giovanna , Pedrazzi Giuseppe , Meleti Marco , Manfredi Maddalena , Migliario Mario , Brucoli Matteo , Greco Lucchina Alberta , Mortellaro Carmen , Vescovi Paolo
Published: May 2018

Introduction:

Different osteotomy techniques have been proposed in order to improve postoperative course of impacted third molar extraction. The aim is to evaluate the possible advantages achieved with erbium yttrium–aluminum–garnet (Er:YAG) laser osteotomy compared with traditional burs.

Materials and Methods:

Seventy-six extractions were randomly classified into 2 groups according to osteotomy instrument: group 1 (G1)—Er:YAG laser: 35 patients; group 2 (G2)—traditional bur: 41 patients. Intraoperative parameters: total time, stitches number, and patient compliance. Postoperative: pain, health-related quality of life (HR-QoL), need for analgesics, edema, trismus, intra- and extraoral hematoma, and postoperative complications.

Results:

Mean time for G1 resulted 1069.4 seconds; for G2 1913.5 seconds (P < 0.0001). Mean number of stitches (P = 0.773) and patient compliance (P = 0.063) were not statistically different. Regarding pain, mean visual analog scale (VAS), and numeric rating scale (NRS) scores were lower in G1 than in G2. Statistically significant differences were highlighted at days 0, 1, and 3 with VAS scale and at days 0, 1, 3, and 7 with NRS scale. The HR-QoL scores resulted lower in G1 than in G2 (P < 0.0001). Mean facial swelling and trismus resulted statistically lower in G1 than in G2 at day 2 (P < 0.0001). Trismus resulted statistically lower in G1 than in G2 at days 2 (P < 0.0001) and 7 (P = 0.004). Two patients (5.71%) of subcutaneous emphysema was recorded in G1 and 2 patients (4.88%) of lip paresthesia in G2.

Conclusion:

Data confirm that the use of Er:YAG laser for osteotomy may achieve several advantages both technical and biological.
Endoscopically Assisted Transoral Gap Arthroplasty of the Temporomandibular Joint Ankylosis in a Pediatric Patient
Authors: Abdelazeem Mohamed Hazem , Erdogan Özgür , Awad Tarek Ahmed
Published: May 2018

Surgical management of temporomandibular joint (TMJ) ankylosis in children is often challenging and may result in various complications such as facial nerve injury and visible scar. In this clinical report, the authors present minimally invasive management of a 9-year-old boy with bilateral post-traumatic TMJ ankylosis. The ankylotic TMJs were addressed and gap arthoplasties were performed by endoscopically assisted transoral approach. The risk of facial nerve injury is minimized and facial scar was prevented by avoiding extraoral incision. Mandibular movements in 3 directions were satisfactory at 3rd postoperative month.
Cervical Tracheal Resection and Anastomosis for Postintubation Tracheal Stenosis
Authors: Kanlikama Muzaffer , Celenk Fatih , Gonuldas Burhanettin , Gulsen Secaattin
Published: May 2018

In this study the authors evaluated the outcomes of tracheal resection and anastomosis in postintubation tracheal stenosis. The authors also aimed to identify clinical and radiological factors associated with restenosis. Thirty-four consecutive patients were included in the study. Patients with subglottic stenosis who underwent procedures involving cricoid cartilage and patients with other etiologies were excluded from the study. Univariate analysis was performed to determine the risk factors for restenosis. Receiver operating characteristic (ROC) curves were generated for the diameter of the narrowest part of the trachea (Dst) and the distance between cricoid cartilage and stenosis (Dcs). Of the 34 patients, 31 (91.1%) patients were successfully decannulated. Nineteen (55.8%) patients had complications. After univariate analysis, Dst (P = 0.001), Dcs (P = 0.001), smoking (P = 0.007) and grade of the stenosis (P = 0.003) were significantly associated with restenosis. The sensitivity and specificity were 90.9% and 77.3%, respectively, when the cutoff value for Dst was 4 mm. Sensitivity and specificity were 72.7% and 100%, respectively, when the cutoff value for Dcs was 10 mm. Tracheal resection and anastomosis is an effective surgical method for treating postintubation tracheal stenosis. In our series, 91.1% of the patients with postintubation tracheal stenosis were successfully decannulated. Restenosis was the most common complication. The diameter of the narrowest part of the trachea (Dst), the distance between cricoid cartilage and stenosis (Dcs), smoking and grade of stenosis were significantly associated with restenosis.
Morphology-based differences in the thermal response of freshwater phytoplankton
Authors: Segura Angel M. , Sarthou Florencia , Kruk Carla
Published: May 2018

The thermal response of maximum growth rate in morphology-based functional groups (MBFG) of freshwater phytoplankton is analysed. Contrasting an exponential Boltzmann–Arrhenius with a unimodal model, three main features were evaluated: (i) the activation energy of the rise (
E
r
), (ii) the presence of a break in the thermal response and (iii) the activation energy of the fall (
E
f
). The whole dataset (
N
= 563) showed an exponential increase (
E
r
∼ 0.5), a break around 24°C and no temperature dependence after the breakpoint (
E
f
= 0). Contrasting thermal responses among MBFG were found. All groups showed positive activation energy (
E
r
> 0), four showed no evidence of decline in growth rate (temperature range = 0–35°C) and two presented a breakpoint followed by a sharp decrease in growth rate. Our results evidenced systematic differences between MBFG in the thermal response and a coherent response significantly related to morphological traits other than size (i.e. within MBFG). These results provide relevant information for water quality modelling and climate change predictions.
Dictating anisotropic electric conductivity of a transparent copper nanowire coating by the surface structure of wood
Authors: Guo Huizhang , Büchel Martin , Li Xing , Wäckerlin Aneliia , Chen Qing , Burgert Ingo
Published: May 2018

In this article, a robust, air-stable, flexible and transparent copper (Cu) nanowire (NW) network coating on the surface of the wood is presented, based on a fusion welding of the Cu NWs by photonic curing. Thereby, an anisotropic conductivity can be achieved, which is originating from the structural organization of the wood body and its surface. Furthermore, the Cu NWs are protected from oxidation or wear by a commercially available paraffin wax—polyolefin, which also results in surface water repellency. The developed processing steps present a facile and flexible routine for applying Cu NW transparent conductors to abundant biomaterials and solve current manufacturing obstacles for corrosion-resistant circuits while keeping the natural appearance of the substrate. It may open a venue for more extensive utilization of materials from renewable resources such as wood for electronic devices in smart buildings or mobility applications.
In vivo
impact testing on a lengthened femur with external fixation: a future option for the non-invasive monitoring of fracture healing?
Authors: Mattei Lorenza , Di Puccio Francesca , Marchetti Stefano
Published: May 2018

Non-invasive methods for assessing fracture healing are crucial for biomedical engineers. An approach based on mechanical vibrations was tried out in the 1990s, but was soon abandoned due to insufficiently advanced technologies. The same approach is re-proposed in the present study in order to monitor the healing process of a lengthened femur with an external fixator. The pins screwed into the bone were exploited for the impact testing (IT) to excite the bone and capture its response. Transmission through the soft tissues was thus prevented, and the quality of the signals was improved. Impact tests were performed every three to four weeks for five months. Unfortunately, after seven weeks, some pins were removed due to infection, and thus, the system was modified. Two different configurations were considered: before and after pin removal. An additional configuration was examined in the last two sessions, when the fixator body was removed, while four pins were left in the femur. The evolution of the frequency response function and of the resonant frequencies of the system were analysed for the duration of the monitoring period. The IT results were compared to the indications provided by X-ray images. During the evolution of the callus from the soft phase to the woven bone, the resonant frequencies of the system were found to increase by approximately 2–3% per week. The largest increase (approx. 22%) was observed for the first resonant frequency. After formation of the woven bone, the vibratory response remained almost the same, suggesting that the healing assessment could be related to the relative variation in the resonant frequencies. The results presented support the application of the IT approach for fracture healing assessment.
Einstein in Oxford
Authors: Fox Robert
Published: May 2018

Albert Einstein made three visits to Oxford between 1931 and 1933, staying for a month in the spring of each year. For our understanding of Einstein's work, the Rhodes Memorial Lectures that he delivered during his first visit are of special interest. They show him in a period of intense rethinking of his cosmological views in the light of Edwin Hubble's recent evidence in favour of an expanding universe, an idea that Einstein had hitherto opposed. The lectures, heavily mathematical and delivered in German, were challenging. Nevertheless, they were well received, and Frederick Lindemann (later Lord Cherwell) saw them as a springboard for a continuing association between Einstein and the University's Clarendon Laboratory. To that end, Lindemann persuaded his college, Christ Church, to invite Einstein for a month in 1932 and each of the four years that followed. The arrangement, part of Lindemann's plan to revitalize Oxford physics, was soon overtaken by political events in Germany and Einstein's emigration to Princeton in October 1933.
Structural design of the minute clypeasteroid echinoidEchinocyamus pusillus
Authors: Grun Tobias B. , Nebelsick James H.
Published: May 2018

The clypeasteroid echinoid skeleton is a multi-plated, light-weight shell construction produced by biomineralization processes. In shell constructions, joints between individual elements are considered as weak points, yet these echinoid skeletons show an extensive preservation potential in both Recent and fossil environments. The remarkable strength of the test is achieved by skeletal reinforcement structures and their constructional layouts. Micro-computed tomography and scanning electron microscopy are used for microstructural and volumetric analyses of the echinoid's skeleton. It is shown that strengthening mechanisms act on different hierarchical levels from the overall shape of the skeleton to skeletal interlocking. The tight-fitting and interlocking plate joints lead to a shell considered to behave as a monolithic structure. The plate's architecture features distinct regions interpreted as a significant load-transferring system. The internal support system follows the segmentation of the remaining skeleton, where sutural layout and stereom distribution are designed for effective load transfer. The structural analysis of the multi-plated, yet monolithic skeleton ofEchinocyamus pusillusreveals new aspects of the micro-morphology and its structural relevance for the load-bearing behaviour. The analysed structural principles allowE. pusillusto be considered as a role model for the development of multi-element, light-weight shell constructions.
Stable genetic structure and connectivity in pollution-adapted and nearby pollution-sensitive populations ofFundulus heteroclitus
Authors: Nunez Joaquin C. B. , Biancani Leann M. , Flight Patrick A. , Nacci Diane E. , Rand David M. , Crawford Douglas L. , Oleksiak Marjorie F.
Published: May 2018

Populations of the non-migratory estuarine fishFundulus heteroclitusinhabiting the heavily polluted New Bedford Harbour (NBH) estuary have shown inherited tolerance to local pollutants introduced to their habitats in the past 100 years. Here we examine two questions: (i) Is there pollution-driven selection on the mitochondrial genome across a fine geographical scale? and (ii) What is the pattern of migration among sites spanning a strong pollution gradient? Whole mitochondrial genomes were analysed for 133F. heteroclitusfrom seven nearby collection sites: four sites along the NBH pollution cline (approx. 5 km distance), which had pollution-adapted fish, as well as one site adjacent to the pollution cline and two relatively unpolluted sites about 30 km away, which had pollution-sensitive fish. Additionally, we used microsatellite analyses to quantify genetic variation over threeF. heteroclitusgenerations in both pollution-adapted and sensitive individuals collected from two sites at two different time points (1999/2000 and 2007/2008). Our results show no evidence for a selective sweep of mtDNA in the polluted sites. Moreover, mtDNA analyses revealed that both pollution-adapted and sensitive populations harbour similar levels of genetic diversity. We observed a high level of non-synonymous mutations in the most polluted site. This is probably associated with a reduction inNeand concomitant weakening of purifying selection, a demographic expansion following a pollution-related bottleneck or increased mutation rates. Our demographic analyses suggest that isolation by distance influences the distribution of mtDNA genetic variation between the pollution cline and the clean populations at broad spatial scales. At finer scales, population structure is patchy, and neither spatial distance, pollution concentration or pollution tolerance is a good predictor of mtDNA variation. Lastly, microsatellite analyses revealed stable population structure over the last decade.
Fluctuations in annual climatic extremes are associated with reproductive variation in resident mountain chickadees
Authors: Kozlovsky Dovid Y. , Branch Carrie L. , Pitera Angela M. , Pravosudov Vladimir V.
Published: May 2018

Mounting evidence suggests that we are experiencing rapidly accelerating global climate change. Understanding how climate change may affect life is critical to identifying species and populations that are vulnerable. Most current research focuses on investigating how organisms may respond to gradual warming, but another effect of climate change is extreme annual variation in precipitation associated with alternations between drought and unusually heavy precipitation, like that exhibited in the western regions of North America. Understanding climate change effects on animal reproductive behaviour is especially important, because it directly impacts population persistence. Here, we present data on reproduction in nest-box breeding, resident mountain chickadees inhabiting high and low elevations in the Sierra Nevada across 5 years. These 5 years of data represent the full range of climatic variation from the largest drought in five centuries to one of the heaviest snow years on record. There were significant differences in most reproductive characteristics associated with variation in climate. Both climate extremes were negatively associated with reproductive success at high and low elevations, but low-elevation chickadees had worse reproductive success in the largest drought year while high-elevation chickadees had worse reproductive success in the heaviest snow year. Considering that the frequency of extreme climate swings between drought and snow is predicted to increase, such swings may have negative effects on chickadee populations across the entire elevation gradient, as climatic extremes should favour different adaptations. Alternatively, it is possible that climate fluctuations might favour preserving genetic variation allowing for higher resilience. It is too early to make specific predictions regarding how increased frequency of extreme climate fluctuation may impact chickadees; however, our data suggest that even the most common species may be susceptible.
Modelling of retinal vasculature based on genetically tuned parametric L-system
Authors: Aghamirmohammadali Seyed Mohammad Ali , Bozorgmehry Boozarjomehry Ramin , Abdekhodaie Mohammad
Published: May 2018

Structures of retinal blood vessels are of great importance in diagnosis and treatment of diseases that affect the eyes. Parametric Lindenmayer system (L-system) is one of the powerful rule-based methods that has a great capability for generating tree-like structures using simple rewriting rules. In this study, a novel framework, which can be used to model the retinal vasculature based on available images, has been proposed. This framework presents a solution to special instance of a general open problem, the L-system inverse problem, in which L-system rules should be obtained based on images representing a particular tree-like structure. In this study, genetic algorithm with a novel objective function based on feature matching and an L-system grammar comparison has been used along with nonlinear regression to solve the parametric L-system inverse problem. The resulting L-system growth rules have been employed to predict inaccessible vascular branches. Graphical and quantitative comparison between model results and target structures of different case studies reveals that the proposed framework can be used to generate the structure of retinal blood vessels accurately. Even in the cases lacking sufficient image data, it can provide acceptable predictions.
Development of the HPLC–ELSD method for the determination of phytochelatins and glutathione inPerilla frutescensunder cadmium stress conditions
Authors: Zheng Xinyu , Chen Shen , Zheng Meiqin , Peng Jun , He Xiaosan , Han Yongming , Zhu Jingjing , Xiao Qingtie , Lv Rixin , Lin Ruiyu
Published: May 2018

A rapid, accurate and simple method was developed for the simultaneous determination of glutathione (GSH) and phytochelatins (PCs) by high-performance liquid chromatography (HPLC) with an evaporative light-scattering detector. GSH, phytochelatin 2 (PC2), PC3, PC4, PC5and PC6can be separated with baseline separation within 9 min using a Venusil AA column (250 mm × 4.6 mm i.d., 5 µm particle sizes). Acetonitrile and water containing 0.1% trifluoroacetic acid (0.1%) were employed as the mobile phase for the gradient elution. The drift tube temperature and flow rate of the carrier gas (N2) were 50°C and 1.5 l min−1, respectively. Under optimum conditions, good linear regression equations of six analytes were obtained with the detection limits ranging from 0.2 to 0.5 µg ml−1. The proposed method has been applied successfully for the quantification of GSH and PCs inPerilla frutescens(a cadmium hyperaccumulator) under cadmium stress. The recoveries were between 82.9% and 115.3%.
Fe
3
O
4
nanoparticle-coated mushroom source biomaterial for Cr(VI) polluted liquid treatment and mechanism research
Authors: Wang Can , Liu Huakang , Liu Zizhao , Gao Yufeng , Wu Bin , Xu Heng
Published: May 2018

Agrocybe cylindracea
substrate–Fe
3
O
4
(ACS–Fe
3
O
4
), a Fe
3
O
4
nanoparticle-coated biomaterial derived from agriculture waste from mushroom cultivation, was developed to remove hexavalent chromium (Cr(VI)) from liquid. After modification, material surface became uneven with polyporous and crinkly structure which improved Cr-accommodation ability in a sound manner. Optimized by the Taguchi method, Cr(VI) removal percentage was up to 73.88 at 240 min, 40°C, pH 3, Cr(VI) concentration 200 mg l
−1
, dosage 12 g l
−1
, rpm 200. The efficient Cr(VI) removal was due to the combined effect of adsorption and redox. In addition, verification test using tannery wastewater, with removal percentage of Cr(VI) and total Cr reaching 98.35 and 95.6, provided further evidence for the efficiency and feasibility of ACS–Fe
3
O
4
. The effect of storage time of the material on Cr(VI) removal was small, which enhanced its value in practical application. Results indicated that metal removal was mainly influenced by solution concentration, adsorbent dosage and treatment time. The experimental data obtained were successfully fitted with the Langmuir isotherm model. Thermodynamic study indicated the endothermic nature of the process. The results confirmed that ACS–Fe
3
O
4
as novel material derived from waste, with long-term stability, could be applied for heavy metal removal from wastewater and waste cycling.
Behavioural elements and sensory cues involved in sexual isolation betweenDrosophila melanogasterstrains
Authors: Grillet Micheline , Ferveur Jean-François , Everaerts Claude
Published: May 2018

Sensory cues exchanged during courtship are crucial for mate choice: if they show intraspecific divergence, this may cause or reinforce sexual isolation between strains, ultimately leading to speciation. There is a strong asymmetric sexual isolation betweenDrosophila melanogasterfemales from Zimbabwe (Z) and males from all other populations (M). While M and Z flies of both sexes show different cuticular pheromones, this variation is only partly responsible for the intraspecific isolation effect. Male acoustic signals are also partly involved in sexual isolation. We examined strain-specific courtship behaviour sequences to determine which body parts and sensory appendages may be involved in sexual isolation. Using two strains representative of the Z- and M-types, we manipulated sensory cues and the social context; we then measured the consequence of these manipulations on courtship and copulation. Our data suggest that Z females mated best with males whose sensory characteristics matched those of Z males in both quantity and quality. M females were less choosy and much less influenced by the sensory and social contexts. Differences in emission and reception of sensory signals seen between Z and M flies may lead to the concerted evolution of multiple sensory channel, thereby shaping a population-specific mate recognition system.
Monogamy promotes altruistic sterility in insect societies
Authors: Davies Nicholas G. , Gardner Andy
Published: May 2018

Monogamy is associated with sibling-directed altruism in multiple animal taxa, including insects, birds and mammals. Inclusive-fitness theory readily explains this pattern by identifying high relatedness as a promoter of altruism. In keeping with this prediction, monogamy should promote the evolution of voluntary sterility in insect societies if sterile workers make for better helpers. However, a recent mathematical population-genetics analysis failed to identify a consistent effect of monogamy on voluntary worker sterility. Here, we revisit that analysis. First, we relax genetic assumptions, considering not only alleles of extreme effect—encoding either no sterility or complete sterility—but also alleles with intermediate effects on worker sterility. Second, we broaden the stability analysis—which focused on the invasibility of populations where either all workers are fully sterile or all workers are fully reproductive—to identify where intermediate pure or mixed evolutionarily stable states may occur. Third, we consider a broader range of demographically explicit ecological scenarios relevant to altruistic worker non-reproduction and to the evolution of eusociality more generally. We find that, in the absence of genetic constraints, monogamy always promotes altruistic worker sterility and may inhibit spiteful worker sterility. Our extended analysis demonstrates that an exact population-genetics approach strongly supports the prediction of inclusive-fitness theory that monogamy promotes sib-directed altruism in social insects.
Nest-site competition and killing by invasive parakeets cause the decline of a threatened bat population
Authors: Hernández-Brito Dailos , Carrete Martina , Ibáñez Carlos , Juste Javier , Tella José L.
Published: May 2018

The identification of effects of invasive species is challenging owing to their multifaceted impacts on native biota. Negative impacts are most often reflected in individual fitness rather than in population dynamics of native species and are less expected in low-biodiversity habitats, such as urban environments. We report the long-term effects of invasive rose-ringed parakeets on the largest known population of a threatened bat species, the greater noctule, located in an urban park. Both species share preferences for the same tree cavities for breeding. While the number of parakeet nests increased by a factor of 20 in 14 years, the number of trees occupied by noctules declined by 81%. Parakeets occupied most cavities previously used by noctules, and spatial analyses showed that noctules tried to avoid cavities close to parakeets. Parakeets were highly aggressive towards noctules, trying to occupy their cavities, often resulting in noctule death. This led to a dramatic population decline, but also an unusual aggregation of the occupied trees, probably disrupting the complex social behaviour of this bat species. These results indicate a strong impact through site displacement and killing of competitors, and highlight the need for long-term research to identify unexpected impacts that would otherwise be overlooked.
An empirical study of the
per capita
yield of science Nobel prizes: is the US era coming to an end?
Authors: Gros Claudius
Published: May 2018

We point out that the Nobel prize production of the USA, the UK, Germany and France has been in numbers that are large enough to allow for a reliable analysis of the long-term historical developments. Nobel prizes are often split, such that up to three awardees receive a corresponding fractional prize. The historical trends for the fractional number of Nobelists per population are surprisingly robust, indicating in particular that the maximum Nobel productivity peaked in the 1970s for the USA and around 1900 for both France and Germany. The yearly success rates of these three countries are to date of the order of 0.2–0.3 physics, chemistry and medicine laureates per 100 million inhabitants, with the US value being a factor of 2.4 down from the maximum attained in the 1970s. The UK in contrast managed to retain during most of the last century a rate of 0.9–1.0 science Nobel prizes per year and per 100 million inhabitants. For the USA, one finds that the entire history of science Noble prizes is described on a
per capita
basis to an astonishing accuracy by a single large productivity boost decaying at a continuously accelerating rate since its peak in 1972.
Application of low-order potential solutions to higher-order vertical traction boundary problems in an elastic half-space
Authors: Taylor Adam G. , Chung Jae H.
Published: May 2018

New solutions of potential functions for the bilinear vertical traction boundary condition are derived and presented. The discretization and interpolation of higher-order tractions and the superposition of the bilinear solutions provide a method of forming approximate and continuous solutions for the equilibrium state of a homogeneous and isotropic elastic half-space subjected to arbitrary normal surface tractions. Past experimental measurements of contact pressure distributions in granular media are reviewed in conjunction with the application of the proposed solution method to analysis of elastic settlement in shallow foundations. A numerical example is presented for an empirical ‘saddle-shaped’ traction distribution at the contact interface between a rigid square footing and a supporting soil medium. Non-dimensional soil resistance is computed as the reciprocal of normalized surface displacements under this empirical traction boundary condition, and the resulting internal stresses are compared to classical solutions to uniform traction boundary conditions.
Stability transitions of an axially moving string subjected to a distributed follower force
Authors: Lad Pranav , Kartik V.
Published: May 2018

The transverse vibrations of an axially moving string that is subjected to a distributed follower force are examined here. This model provides an insight into the complex dynamics of seemingly simpler systems such as silicon wafer cutting using wire saws, and aerial or marine towing, where a relatively long flexible structure is dragged through fluid. The equation of motion is derived and it includes the axial variation in the tension that arises due to acceleration and the follower force. As the exact analytical solution of this equation is difficult to determine, the approximate closed-form modal solution of a non-travelling counterpart of the system is obtained using the asymptotic technique, which is then used as a basis to obtain the numerical solution for the axially moving string. The effect of the follower force and viscous dissipation on the eigenstructure of the system is investigated. Mathematical operations such as the Hermite form and the Routh–Hurwitz criterion are applied to the characteristic polynomial to investigate the dynamic behaviour of these modes. The semi-analytical approach presented explains the ‘mathematical’ instability (in the absence of damping) that arises when both axial transport and follower force are simultaneously present. An unusual transition of the dynamic behaviour from the stable to the overdamped and then directly to the unstable regime is observed.
Simultaneity of centres in ℤq-equivariant systems
Authors: Giné Jaume , Llibre Jaume , Valls Claudia
Published: May 2018

We study the simultaneous existence of centres for two families of planarZq-equivariant systems. First, we give a short review aboutZq-equivariant systems. Next, we present the necessary and sufficient conditions for the simultaneous existence of centres for aZ2-equivariant cubic system and for aZ2-equivariant quintic system.
Arrival order and release from competition does not explain why haplochromine cichlids radiated in Lake Victoria
Authors: Muschick Moritz , Russell James M. , Jemmi Eliane , Walker Jonas , Stewart Kathlyn M. , Murray Alison M. , Dubois Nathalie , Stager J. Curt , Johnson Thomas C. , Seehausen Ole
Published: May 2018

The frequent occurrence of adaptive radiations on oceanic islands and in lakes is often attributed to ecological opportunity resulting from release from competition where arrival order among lineages predicts which lineage radiates. Thispriority effectoccurs when the lineage that arrives first expands its niche breadth and diversifies into a set of ecological specialists with associated monopolization of the resources. Later-arriving species do not experience ecological opportunity and do not radiate. While theoretical support and evidence from microbial experiments for priority effects are strong, empirical evidence in nature is difficult to obtain. Lake Victoria (LV) is home to an exceptional adaptive radiation of haplochromine cichlid fishes, where 20 trophic guilds and several hundred species emerged in just 15 000 years, the age of the modern lake that was preceded by a complete desiccation lasting several thousand years. However, while about 50 other lineages of teleost fish also have established populations in the lake, none of them has produced more than two species and most of them did not speciate at all. Here, we test if the ancestors of the haplochromine radiation indeed arrived prior to the most competent potential competitors, ‘tilapias’ and cyprinids, both of which have made rapid radiations in other African lakes. We assess LV sediment core intervals from just before the desiccation and just after refilling for the presence of fossil fish teeth. We show that all three lineages were present when modern LV began to fill with water. We conclude that the haplochromines' extraordinary radiation unfolded in the presence of potentially competing lineages and cannot be attributed to a simple priority effect.
Unpicking allosteric mechanisms of homo-oligomeric proteins by determining their successive ligand binding constants
Authors: Gruber Ranit , Horovitz Amnon
Published: May 2018

Advances in native mass spectrometry and single-molecule techniques have made it possible in recent years to determine the values of successive ligand binding constants for large multi-subunit proteins. Given these values, it is possible to distinguish between different allosteric mechanisms and, thus, obtain insights into how various bio-molecular machines work. Here, we describe for ring-shaped homo-oligomers, in particular, how the relationship between the values of successive ligand binding constants is diagnostic for concerted, sequential and probabilistic allosteric mechanisms.

This article is part of a discussion meeting issue ‘Allostery and molecular machines’.
Substrate protein dependence of GroEL–GroES interaction cycle revealed by high-speed atomic force microscopy imaging
Authors: Noshiro Daisuke , Ando Toshio
Published: May 2018

A double-ring-shaped tetradecameric GroEL complex assists proper protein folding in cooperation with the cochaperonin GroES. The dynamic GroEL–GroES interaction reflects the allosteric intra- and inter-ring communications and the chaperonin reaction. Therefore, revealing this dynamic interaction is essential to understanding the allosteric communications and the operation mechanism of GroEL. Nevertheless, how this interaction proceeds in the chaperonin cycle has long been controversial. Here, we directly image the dynamic GroEL–GroES interaction under conditions with and without foldable substrate protein using high-speed atomic force microscopy. Then, the imaging results obtained under these conditions and our previous results in the presence of unfoldable substrate are compared. The molecular movies reveal that the entire reaction pathway is highly complicated but basically identical irrespective of the substrate condition. A prominent (but moderate) difference is in the population distribution of intermediate species: symmetric GroEL : GroES
2
and asymmetric GroEL : GroES
1
complexes, and GroES–unbound GroEL. This difference is mainly attributed to the longer lifetime of GroEL : GroES
1
complexes in the presence of foldable substrate. Moreover, the inter-ring communication, which is the basis for the alternating action of the two rings, occurs at two distinct (GroES association and dissociation) steps in the main reaction pathway, irrespective of the substrate condition.

This article is part of a discussion meeting issue ‘Allostery and molecular machines’.
Molecular switch-like regulation in motor proteins
Authors: Tafoya Sara , Bustamante Carlos
Published: May 2018

Motor proteins are powered by nucleotide hydrolysis and exert mechanical work to carry out many fundamental biological tasks. To ensure their correct and efficient performance, the motors' activities are allosterically regulated by additional factors that enhance or suppress their NTPase activity. Here, we review two highly conserved mechanisms of ATP hydrolysis activation and repression operating in motor proteins—the glutamate switch and the arginine finger—and their associated regulatory factors. We examine the implications of these regulatory mechanisms in proteins that are formed by multiple ATPase subunits. We argue that the regulatory mechanisms employed by motor proteins display features similar to those described in small GTPases, which require external regulatory elements, such as dissociation inhibitors, exchange factors and activating proteins, to switch the protein's function ‘on’ and ‘off'. Likewise, similar regulatory roles are taken on by the motor's substrate, additional binding factors, and even adjacent subunits in multimeric complexes. However, in motor proteins, more than one regulatory factor and the two mechanisms described here often underlie the machine's operation. Furthermore, ATPase regulation takes place throughout the motor's cycle, which enables a more complex function than the binary ‘active' and ‘inactive' states.

This article is part of a discussion meeting issue ‘Allostery and molecular machines'.
Interplay of self-association and conformational flexibility in regulating protein function
Authors: Garton Michael , MacKinnon Stephen S. , Malevanets Anatoly , Wodak Shoshana J.
Published: May 2018

Many functional roles have been attributed to homodimers, the most common mode of protein self-association, notably in the regulation of enzymes, ion channels, transporters and transcription factors. Here we review findings that offer new insights into the different roles conformational flexibility plays in regulating homodimer function. Intertwined homodimers of two-domain proteins and their related family members display significant conformational flexibility, which translates into concerted motion between structural domains. This flexibility enables the corresponding proteins to regulate function across family members by modulating the spatial positions of key recognition surfaces of individual domains, to either maintain subunit interfaces, alter them or break them altogether, leading to a variety of functional consequences. Many proteins may exist as monomers but carry out their biological function as homodimers or higher-order oligomers. We present early evidence that in such systems homodimer formation primes the protein for its functional role. It does so by inducing elevated mobility in protein regions corresponding to the binding epitopes of functionally important ligands. In some systems this process acts as an allosteric response elicited by the self-association reaction itself. Our analysis furthermore suggests that the induced extra mobility likely facilitates ligand binding through the mechanism of conformational selection.

This article is part of a discussion meeting issue ‘Allostery and molecular machines’.
Haemophilus to meningococci transfer of beta-lactamase
Authors: Hong Eva , Deghmane Ala-Eddine , Taha Muhamed-Kheir
Published: May 2018

We report the detection in France of a beta-lactamase producing invasive meningococcal isolate. Whole genome sequencing of the isolate revealed ROB-1 type beta-lactamase that is frequently encountered in Haemophilus influenzae suggesting horizontal transfer between isolates of these bacterial species. Beta-lactamases are exceptional in meningococci with no reports from more than two decades. This report is worrying as the expansion of such isolates may jeopardize the effective treatment against invasive meningococcal disease.
Comparative Proteomics Reveals Characteristic Proteins on Praziquantel-resistance inSchistosoma mansoni
Authors: Pinto-Almeida António , Mendes Tiago , Ferreira Pedro , Belo Silvana , Freitas Anibal Fernanda de , Allegretti Silmara Marques , Carrilho Emanuel , Afonso Ana
Published: May 2018

The extensive use of Praziquantel (PZQ), the only drug available to treat schistosomiasis, has brought concern about the emergence of PZQ-resistance/tolerance bySchistosomaspp., thus reaffirming an urge for the development of new treatment alternatives. Therefore, it is imperative and urgent to study this phenomenon trying to understand what is involved in its occurrence. Studies ofSchistosomaspp. genome, transcriptome and proteome are crucial to better understand this situation. By stepwise drug pressure from a fully susceptible parasite strain, our group selected aS. mansonivariant strain stably resistant to PZQ and isogenic to its fully susceptible parental counterpart, except for the genetic determinants of PZQ-resistance phenotype. Based on this, the objective of this study was to compare the proteomes of both strains, identifying proteins from male and female adult worms of PZQ-resistant and PZQ-susceptible strains, exposed and not exposed to PZQ, which were separated by high-resolution two-dimensional electrophoresis and sequenced by high throughput LC-MS/MS. Likewise, this work is extremely relevant since for the first time the proteome of aS. mansoniPZQ-resistant strain is studied and compared to the proteome of the respectiveS. mansoniPZQ-susceptible strain. This study identified 60S. mansoniproteins, some of which differentially expressed in either strain, which may putatively be involved in the PZQ-resistance phenomenon. This information represents substantial progress towards deciphering the worm proteome. Furthermore, these data may constitute an informative source for further investigations into PZQ-resistance and increase the possibility of identifying proteins related to this condition, possibly contributing to avoid or decrease the likelihood of development and spread of PZQ-resistance. This is an innovative study that opens doors to PZQ-resistance surveys, contributing to discover a solution to PZQ-resistance problem, as suggests new potential targets for study.
RsmV a small non-coding regulatory RNA in Pseudomonas aeruginosa that sequesters RsmA and RsmF from target mRNAs
Authors: Janssen Kayley H. , Diaz Manisha R. , Gode Cindy J. , Wolfgang Matthew C. , Yahr Timothy L.
Published: May 2018

The Gram-negative opportunistic pathogen Pseudomonas aeruginosa has distinct genetic programs that favor either acute or chronic virulence gene expression. Acute virulence is associated with twitching and swimming motility, expression of a type III secretion system (T3SS), and the absence of alginate, Psl, or Pel polysaccharide production. Traits associated with chronic infection include growth as a biofilm, reduced motility, and expression of a type VI secretion system (T6SS). The Rsm post-transcriptional regulatory system plays an important role in the inverse control of phenotypes associated with acute and chronic virulence. RsmA and RsmF are RNA-binding proteins that interact with target mRNAs to control gene expression at the post-transcriptional level. Previous work found that RsmA activity is controlled by at least three small, non-coding regulatory RNAs (RsmW, RsmY, and RsmZ). In this study, we took an in-silico approach to identify additional sRNAs that might function in the sequestration of RsmA and/or RsmF and identified RsmV, a 192 nt transcript with four predicted RsmA/RsmF consensus binding sites. RsmV is capable of sequestering RsmA and RsmF in vivo to activate translation of tssA1, a component of the T6SS, and to inhibit T3SS gene expression. Each of the predicted RsmA/RsmF consensus binding sites contribute to RsmV activity. Electrophoretic mobility shifts assays show that RsmF binds RsmV with >10-fold higher affinity than RsmY and RsmZ. Gene expression studies revealed that the temporal expression pattern of RsmV differs from RsmW, RsmY, and RsmZ. These findings suggest that each sRNA may play distinct roles in controlling RsmA and RsmF activity.

IMPORTANCE

The role of RsmF in post-transcriptional control of gene expression remains enigmatic. While numerous rsmA-dependent phenotypes are more pronounced in an rsmAF double mutant, deletion of rsmF alone has only modest effects. Understanding mechanisms that control RsmF activity will provide insight into additional roles for RsmF. In the current study we identify RsmV as an sRNA that controls RsmA and RsmF activity, and show that RsmV, RsmW, RsmY, and RsmZ are differentially expressed during growth.
Adipose tissue in health and disease through the lens of its building blocks
Authors: Lenz Michael , Arts Ilja C.W. , Peeters Ralf L.M. , de Kok Theo M. , Ertaylan Gökhan
Published: May 2018

Background

Highly specialized cells work in synergy forming tissues to perform functions required for the survival of organisms. Understanding this tissue-specific cellular heterogeneity and homeostasis is essential to comprehend the development of diseases within the tissue and also for developing regenerative therapies. Cellular subpopulations in the adipose tissue have been related to disease development, but efforts towards characterizing the adipose tissue cell type composition are limited due to lack of robust cell surface markers, limited access to tissue samples, and the labor-intensive process required to identify them.

Results

We propose a framework, identifying cellular heterogeneity while providing state-of-the-art cellular markers for each cell type present in tissues using transcriptomics level analysis. We validate our approach with an independent dataset and present the most comprehensive study of adipose tissue cell type composition to date, determining the relative amounts of 21 different cell types in 779 adipose tissue samples detailing differences across four adipose tissue depots, between genders, across ranges of BMI and in different stages of type-2 diabetes. We also highlight the heterogeneity in reported marker-based studies of adipose tissue cell type composition and provide novel cellular markers to distinguish different cell types within the adipose tissue.

Conclusions

Our study provides a systematic framework for studying cell type composition in a given tissue and valuable insights into adipose tissue cell type heterogeneity in health and disease.
PySight: plug and play photon counting for fast intravital microscopy
Authors: Har-Gil Hagai , Golgher Lior , Israel Shai , Kain David , Cheshnovsky Ori , Parnas Moshe , Blinder Pablo
Published: May 2018

Imaging increasingly large neuronal populations at high rates pushed multi-photon microscopy into the photon-deprived regime. We present PySight, an add-on hardware and software solution tailored for photon-deprived imaging conditions. PySight more than triples the median amplitude of neuronal calcium transients in awake mice, and facilitates single-trial intravital voltage imaging in fruit flies. Its unique data streaming architecture allowed us to image a fruit fly’s olfactory response over 234 ×; 600 ×; 330µm3 at 73 volumes per second, outperforming top-tier imaging setups while retaining over 200 times lower data rates. PySight requires no electronics expertise nor custom synchronization boards, and its open-source software is extensible to any imaging method based on single-pixel (bucket) detectors. PySight offers an optimal data acquisition scheme for ever increasing imaging volumes of turbid living tissue.
The landscape and diagnostic potential of T and B cell repertoire in Immunoglobulin A Nephropathy
Authors: Huang Chen , Li Xuemei , Wu Jinghua , Zhang Wei , Sun Shiren , Lin Liya , Wang Xie , Li Hongmei , Wu Xiaolei , Zhang Peng , Xu Guoshuang , Wan Hanmin , Liu Hongbao , Liu Yuzhen , Chen Dapeng , Zhuo Li , Yang Huanming , Wang Jian , Wang Ling , Liu Xiao
Published: May 2018

Immunoglobulin A Nephropathy (IgAN) is the most common glomerulonephritis worldwide. In IgAN, immune complex deposite in glomerular mesangium, which induce inflammation and affect the kidney’s normal functions. However, the exact pathogenesis of IgAN is still incompletely understood. Further, in current practice the clinical diagnosis relies on needle biopsy on renal tissue. Therefore, a non-invasive method for clinical diagnosis and prognosis surveillance of the disease is in high demand. In this paper, we investigated both the T cell receptor bata chain (TCRB) and immunoglobulin heavy chain (IGH) repertoire of kidney infiltrating and circulating lymphocytes of IgAN patients by immune repertoire high throughput sequencing. We found that the features of TCRB and IGH in the renal tissues were remarkably different from that in blood, including a decreased repertoire diversity and increased IgA and IgG frequency, and more activated B cells. The CDR3 length of PBMC TCRB and IGH in patients is significantly shorter than that in healthy controls, which is the result of both VDJ rearrangement and clone selection. We also found that the IgA1 frequency in the PBMC of IgAN is significant higher than that in other Nephropathy (NIgAN) and healthy control, which is consistent with the previous reports on the level of IgA1 producing B cells and serum IgA1. Significantly, we identified a set of IgAN disease related TCRB and IGH CDR3s, which can be used to distinguish IgAN from NIgAN and healthy controls from the blood with high accuracy. These results indicated that TCRB and IGH repertoire can potentially serve as non-invasive biomarkers for IgAN diagnosis. The characteristics of kidney infiltrating and circulating lymphocytes repertoire shed light on IgAN detection, treatment and surveillance.