bluuebunny/crossref_metadata_2025 huggingface dataset:
Architectural, functional and molecular responses to concentric and eccentric loading in human skeletal muscle
Authors: Franchi M. V. , Atherton P. J. , Reeves N. D. , Flück M. , Williams J. , Mitchell W. K. , Selby A. , Beltran Valls R. M. , Narici M. V.
Published: January 2014

Aim

We investigated architectural, functional and molecular responses of human skeletal muscle to concentric (CON) or eccentric (ECC) resistance training (RT).

Methods

Twelve young males performed 10 weeks of concentric (CON) or eccentric (ECC) resistance training (RT) (n = 6 CON, 6 ECC). An additional 14 males were recruited to evaluate acute muscle fascicle behaviour and molecular signalling in biopsies collected from vastus lateralis (VL) after 30 min of single bouts of CON or ECC exercise. VL volume was measured by magnetic resonance imaging. Muscle architecture (fascicle length, Lf; pennation angle, PA) was evaluated by ultrasonography. Muscle remodelling signals to CON or ECC loading [MAPK/AKT‐mammalian target of rapamycin (mTOR) signalling] and inflammatory pathway (TNFαMurf‐1‐MAFbx) were evaluated by immunoblotting.

Results

Despite the ~1.2‐fold greater load of the ECC group, similar increases in muscle volume (+8% CON and +6% ECC) and in maximal voluntary isometric contraction (+9% CON and +11% ECC) were found after RT. However, increases in Lf were greater after ECC than CON (+12 vs. +5%) while increases in PA were greater in CON than ECC (+30 vs. +5%). Distinct architectural adaptations were associated with preferential growth in the distal regions of VL for ECC (+ECC +8% vs. +CON +2) and mid belly for CON (ECC +7 vs. CON +11%). While MAPK activation (p38MAPK, ERK1/2, p90RSK) was specific to ECC, neither mode affected AKT‐mTOR or inflammatory signalling 30 min after exercise.

Conclusion

Muscle growth with CON and ECC RT occurs with different morphological adaptations reflecting distinct fibre fascicle behaviour and molecular responses.
Reading, Writing, Arithmetic, and Racism? Risks and Benefits to Teaching Children About Intergroup Biases
Authors: Bigler Rebecca S. , Wright Yamanda F.
Published: January 2014

By the time children start formal schooling, they endorse stereotypes and exhibit prejudice on the basis of many traits, including age, attractiveness, disability status, gender, and race. Despite the relevance of these phenomena to children's lives, as well as to understanding historical and contemporary human relations, little consensus exists about whether, when, or how to teach children about intergroup biases (i.e., stereotyping, prejudice, and discrimination). In this article, we review the risks and benefits of learning about intergroup biases among elementary school children. We conclude that lessons about intergroup biases are valuable and call for additional research on how best to maximize their effectiveness for improving intergroup relations while minimizing associated risks.
Clarifying the Contours of Emotion Regulation: Insights From Parent–Child Stress Research
Authors: Laurent Heidemarie K.
Published: January 2014

The way people respond to and recover from stress is a core aspect of emotion regulation, making it important to understand when and how stress response systems become dysregulated. In this article, I discuss a program of research designed to clarify the origins of stress regulation or dysregulation within families. My study highlights how parents with mood dysregulation shape their children's developing stress sensitivity via both inherited and social‐environmental paths, and how such sensitivity aids or impairs regulation depending on the environmental context. The work also points to ways in which the family environment continues to modulate stress sensitivity over time, framing regulation as a dynamic interplay among early and later parental influences, and current conditions, rather than a static outcome. I also discuss implications for conceptualizing stress regulation and points of intervention.
Watch the hands: infants can learn to follow gaze by seeing adults manipulate objects
Authors: Deák Gedeon O. , Krasno Anna M. , Triesch Jochen , Lewis Joshua , Sepeta Leigh
Published: January 2014

Infants gradually learn to share attention, but it is unknown how they acquire skills such as gaze‐following. Deák and Triesch () suggest that gaze‐following could be acquired if infants learn that adults' gaze direction is likely to be aligned with interesting sights. This hypothesis stipulates that adults tend to look at things that infants find interesting, and that infants could learn by noticing this tendency. We tested the plausibility of this hypothesis through video‐based micro‐behavioral analysis of naturalistic parent–infant play. The results revealed that 3‐ to 11‐month‐old infants strongly preferred watching caregivers handle objects. In addition, when caregivers looked away from their infant they tended to look at their own object‐handling. Finally, when infants looked toward the caregiver while she was looking at her own hands, the infant's next eye movement was often toward the caregiver's object‐handling. In this way infants receive adequate naturalistic input to learn associations between their parent's gaze direction and the locations of interesting sights.
Differential influence of safe versus threatening facial expressions on decision‐making during an inhibitory control task in adolescence and adulthood
Authors: Cohen‐Gilbert J.E. , Killgore W.D.S. , White C.N. , Schwab Z.J. , Crowley D.J. , Covell M.J. , Sneider J.T. , Silveri M.M.
Published: January 2014

Social cognition matures dramatically during adolescence and into early adulthood, supported by continued improvements in inhibitory control. During this time, developmental changes in interpreting and responding to social signals such as facial expressions also occur. In the present study, subjects performed a Go No‐Go task that required them to respond or inhibit responding based on threat or safety cues present in facial expressions. Subjects (N = 112) were divided into three age groups: adolescent (12–15 years), emerging adult (18–25 years) and adult (26–44 years). Analyses revealed a significant improvement in accuracy on No‐Go trials, but not Go trials, during both safe and threat face conditions, with changes evident through early adulthood. In order to better identify the decision‐making processes responsible for these changes in inhibitory control, a drift diffusion model (DDM) was fit to the accuracy and reaction time data, generating measures of caution, response bias, nondecision time (encoding + motor response), and drift rate (face processing efficiency). Caution and nondecision time both increased significantly with age while bias towards the Go response decreased. Drift rate analyses revealed significant age‐related improvements in the ability to map threat faces to a No‐Go response while drift rates on all other trial types were equivalent across age groups. These results suggest that both stimulus‐independent and stimulus‐dependent processes contribute to improvements in inhibitory control in adolescence with processing of negative social cues being specifically impaired by self‐regulatory demands. Findings from this novel investigation of emotional responsiveness integrated with inhibitory control may provide useful insights about healthy development that can be applied to better understand adolescent risk‐taking behavior and the elevated incidence of related forms of psychopathology during this period of life.
Relationship between cognitive dysfunction, gait, and motor impairment in children and adolescents with neurofibromatosis type 1
Authors: Champion Joel A , Rose Kristy J , Payne Jonathan M , Burns Joshua , North Kathryn N
Published: January 2014

Aim

Motor skill impairment and cognitive dysfunction are commonly reported features of neurofibromatosis type 1 (NF1). We characterized and determined the relationship between motor impairment, gait variables, and cognitive function in children and adolescents with NF1.

Method

Motor function, gait, and neurocognitive abilities were assessed in 46 children and adolescents with NF1 (26 males, 20 females; age range 7–17y; mean age 11y 1mo, SD 3y 2mo). Tests to establish correlations between neurocognitive, motor, and gait variables were performed.

Results

Compared with normative data, 28/39 of our NF1 cohort demonstrated impaired performance for balance and upper limb coordination and 16/38 for running speed and agility. Gait data revealed a strategy to preserve balance at the expense of velocity, with the unexpected exception of a tendency for reduced base of support. Neurocognitive testing confirmed mean IQ in the low average range (86.0) and deficits in spatial working memory and strategy generation. Significant correlations between a number of neurocognitive measures and motor abilities and gait were identified. The largest associations were between gait width and spatial working memory (r=0.594) and running speed and agility with strategy generation (r=0.549).

Interpretation

We have identified a relationship between balance, running speed and agility, gait, and cognition in children with NF1. Findings suggest a shared abnormal neurodevelopmental process underlying some cognitive and motor abilities in NF1. Results are discussed within the context of evidence highlighting abnormal dopamine‐mediated corticostriatal circuitry in NF1.
Are we being too ‘selective’ about motor control?
Authors: Fowler Eileen , Staudt Loretta
Published: January 2014

This commentary is on the review by Cahill‐Rowley and Rose on pages
522–528 of this issue.
Signalling pathways in pemphigus vulgaris
Authors: Li Xiaoguang , Ishii Norito , Ohata Chika , Furumura Minao , Hashimoto Takashi
Published: January 2014

Acantholysis in pemphigus vulgaris is induced by binding of autoantibodies to desmoglein 3 (Dsg3). The roles of signalling pathways on development of acantholysis have recently been extensively studied. In the study by Sayar et al., recently published in Exp Dermatol, epidermal growth factor receptor (EGFR) signalling was activated in both in vivo and in vitro pemphigus vulgaris experimental models. However, while EGFR inhibitors suppressed activity of p38 mitogen‐activated protein kinase (p38MAPK) linearly, they suppressed activity of c‐Myc and acantholysis in a non‐linear, V‐shaped relationship. These findings indicated complicated interactions among EGFR, p38MAPK and c‐Myc in pemphigus vulgaris pathology.
Selective hair therapy: bringing science to the fiction
Authors: Vogt Annika , Blume‐Peytavi Ulrike
Published: January 2014

Investigations on carrier‐based drug delivery systems for higher selectivity in hair therapy have clearly evolved from dye release and model studies to highly sophisticated approaches, many of which specifically tackle hair indications and the delivery of hair‐relevant molecules. Here, we group recent hair disease‐oriented work into efforts towards (i) improved delivery of conventional drugs, (ii) delivery of novel drug classes, for example biomolecules and (iii) targeted delivery on the cellular/molecular level. Considering the solid foundation of experimental work, it does not take a large step outside the current box of thinking to follow the idea of using large carriers (>500 nm, unlikely to penetrate as a whole) for follicular penetration, retention and protection of sensitive compounds. Yet, reports on particles <200 nm being internalized by keratinocytes and dendritic cells at sites of barrier disruption (e.g., hair follicles) combined with recent advances in nanodermatology add interesting new facets to the possibilities carrier technologies could offer, for example, unprecedented levels of selectivity. The authors provide thought‐provoking ideas on how smart delivery technologies and advances in our molecular understanding of hair pathophysiology could result in a whole new era of hair therapeutics. As the field still largely remains in preclinical investigation, determined efforts towards production of medical grade material and truly translational work are needed to demonstrate surplus value of carrier systems for clinical applications.
Functional characterization of DnaB helicase and its modulation by single‐stranded DNA binding protein in Mycobacterium tuberculosis
Authors: Zhang Hua , Zhang Zhuanmei , Yang Jian , He Zheng‐Guo
Published: January 2014

DnaB is important in the initiation and extension stages of DNA replication. Although DnaB has been studied in many bacterial species, its function in the devastating human pathogen Mycobacterium tuberculosis remains unclear. In this study, an intein‐deleted form of M. tuberculosis DnaB (MtbDnaB) was cloned, expressed and characterized. MtbDnaB exhibited strong 5′ to 3′ helicase and ATPase activities, suggesting that MtbDnaB is a functional homolog of Escherichia coli DnaB. A physical interaction between MtbSSB (single‐stranded binding protein of M. tuberculosis) and MtbDnaB was further identified in vivo and in vitro. The MtbSSB C‐terminal fragment was found to have a critical function in this interaction. Moreover, the helicase activity of MtbDnaB was stimulated by MtbSSB at low concentrations and inhibited at high concentrations. An MtbSSB mutant with decreased binding affinity for ssDNA can stimulate the helicase activity of MtbDnaB over a wider concentration range than wild‐type MtbSSB. These results suggest that MtbSSB assists in the loading of MtbDnaB on the DNA replication fork in M. tuberculosis.

Structured digital abstract

MtbSSB physically interacts with MtbDnaB by two hybrid (View interaction)

MtbDnaB physically interacts with MtbSSB by cross-linking study (View interaction)

MtbDnaB binds to MtbSSB by surface plasmon resonance (View interaction)
Interfacial residues of SpcS chaperone affects binding of effector toxin ExoT in Pseudomonas aeruginosa: novel insights from structural and computational studies
Authors: Dey Supratim , Datta Saumen
Published: January 2014

ExoT belongs to the family of type 3 secretion system (T3SS) effector toxins in Pseudomonas aeruginosa, known to be one of the major virulence determinant toxins that cause chronic and acute infections in immuno‐compromised individuals, burn victims and cystic fibrosis patients. Here, we report the X‐ray crystal structure of the amino terminal fragment of effector toxin ExoT, in complex with full‐length homodimeric chaperone SpcS at 2.1 Å resolution. The full‐length dimeric chaperone SpcS has the conserved α‐β‐β‐β‐α‐β‐β‐α fold of class I chaperones, the characteristic hydrophobic patches for binding effector proteins and a conserved polar cavity at the dimeric interface. The stable crystallized amino terminal fragment of ExoT consists of a chaperone binding domain and a membrane localization domain that wraps around the dimeric chaperone. Site‐directed mutagenesis experiments and a molecular dynamics study complement each other in revealing Asn65, Phe67 and Trp88 as critical dimeric interfacial residues that can strongly influence the effector–chaperone interactions.

Database

The atomic coordinates and structure factors of ExoT–SpcS complex (code 4JMF) have been deposited in the Protein Data Bank Japan (PDBj), Institute for Protein Research, Osaka University.
Trade‐offs among agronomic, energetic, and environmental performance characteristics of corn and prairie bioenergy cropping systems
Authors: Jarchow Meghann E. , Liebman Matt , Dhungel Shashi , Dietzel Ranae , Sundberg David , Anex Robert P. , Thompson Michael L. , Chua Teresita
Published: January 2014

Cellulosic bioenergy production provides opportunities to utilize a range of cropping systems that can enhance the multifunctionality of agricultural landscapes. In a 9‐ha field experiment located on fertile land in Boone County, IA, USA, we directly compared a corn‐soybean rotation harvested for grain, continuous corn harvested for grain and stover, continuous corn harvested for grain and stover with a rye cover crop, newly reconstructed prairie harvested for biomass and fertilized with nitrogen, and unfertilized newly reconstructed prairie harvested for biomass. Comparisons were made using four performance indicators: harvestable yield, net energy balance (NEB), root production, and nutrient balances. We found trade‐offs among systems in terms of the measured performance indicators. Continuous corn systems were the highest yielding, averaging 13 Mg ha−1 of harvested biomass (grain plus stover), whereas fertilized and unfertilized prairies produced the least harvested biomass at 8.8 and 6.5 Mg ha−1, respectively. Mean NEBs were highest in continuous corn systems at 45.1 GJ ha−1, intermediate in the corn‐soybean rotation at 28.6 GJ ha−1, and lowest in fertilized and unfertilized prairies at 11.4 and 10.5 GJ ha−1, respectively. Concomitant with the high yields of the continuous corn systems were the large nutrient requirements of these systems compared to the prairie systems. Continuous corn with rye required three times more nitrogen inputs than fertilized prairie. Root production, on the other hand, was on average seven times greater in the prairie systems than the annual crop systems. On highly fertile soils, corn‐based cropping systems are likely to play an important role in maintaining the high productivity of agricultural landscapes, but alternative cropping systems, such as prairies used for bioenergy production, can produce substantial yield, require minimal externally derived inputs, and can be incorporated into the landscape at strategic locations to maximize the production of other ecosystem services.
Immunohistochemical localization of NALP3 inflammasome in experimental periapical lesions
Authors: Liu S. , Li Q. , Liu Y.
Published: January 2014

Aim

To explore the role of NALP3 inflammasome [NALP3, its effector molecule apoptosis associated speck‐like protein (ASC), caspase‐1, interleukin (IL)‐1β and IL‐18] in the development of periapical lesions in rats.

Methodology

Periapical lesions were developed within 21 days after mandibular first molar pulp exposure in Sprague‐Dawley rats. The animals were randomly sacrificed at 0, 1, 3, 7, 10, 14 and 21 days after pulpal exposure. The bilateral mandibles were extracted for histological processing, then they were haematoxylin‐eosin (HE) stained to examine inflammation infiltration in the apical region and immunohistochemically examined for the NALP3 inflammasome signalling pathway. Data were analysed by one‐way analysis of variance and the Pearson's correlation and linear tendency test.

Results

NALP3 was detected in the cytoplasm of fibroblasts, monocytes, neutrophils, macrophages and vascular endothelial cells in the periapical region. From day 1 to day 21, the number of NALP3‐positive cells ascended and was significantly correlated with the intensity of inflammatory infiltration (r = 0.776, P < 0.01). ASC, caspase‐1, IL‐1β and IL‐18 were all expressed in the inflammatory periapical tissues. The positive cell counts of IL‐1β and IL‐18 were significantly correlated with that of NALP3, and r = 0.718, P < 0.01; r = 0.688, P < 0.01, respectively.

Conclusions

NALP3 inflammasome is expressed in the inflammatory periapical tissues. This cytokine‐signalling pathway may therefore be crucial in the regulatory control of inflammatory responses in periapical tissues and the development of periapical lesions.
Fracture resistance and stress distribution of simulated immature teeth after apexification with mineral trioxide aggregate
Authors: Brito‐Júnior M. , Pereira R. D. , Veríssimo C. , Soares C. J. , Faria‐e‐Silva A. L. , Camilo C. C. , Sousa‐Neto M. D.
Published: January 2014

Aim

To evaluate the effect of adhesive restorations on fracture resistance and stress distribution in teeth with simulated immature apices and apical plugs of mineral trioxide aggregate (MTA).

Methodology

Sixty bovine incisors were sectioned 8 mm above and 12 mm below the cemento‐enamel junction (CEJ). The root canal was enlarged using a diamond bur, resulting in remaining root canal walls with 0.1–0.2 mm of thickness. A 5‐mm apical plug of MTA was placed and the teeth were restored according to the following groups: GP – the root canal was filled with gutta‐percha and endodontic sealer; CR – the root canal was filled with light‐cured composite resin inserted incrementally; FP – a fibre post was cemented into the root canal; and RFP – the fibre post was relined with composite resin prior to the cementation into the root canal. A load was applied on the crown of all teeth at 135° to their long axis until fracture. Data was analysed by one‐way anova and SNK tests (α = 0.05), whilst the fracture pattern was evaluated according to the position of the fracture. Stress distributions in the restored teeth were verified by finite element analysis.

Results

Teeth restored with fibre posts and relined fibre posts were associated with the highest fracture resistance, whilst the GP group had the lowest values. GP and RC groups had similar fracture resistance values (P = 0.109). All fractures types involved the cervical and middle thirds of roots. The GP model had high levels of stress concentration in the cervical and middle thirds of roots. No difference was found amongst the stress concentration in the RC, FP and RFP models.

Conclusion

Restorative protocols alter the fracture resistance and stress distribution of immature teeth after placement of MTA apical plugs.
The survival of indirect composite resin onlays for the restoration of root filled teeth: a retrospective medium‐term study
Authors: Chrepa V. , Konstantinidis I. , Kotsakis G. A. , Mitsias M. E.
Published: January 2014

Aim

To investigate the outcomes of root filled posterior teeth restored with indirect composite resin onlays using tooth and restoration survival as well as the quality of restoration as outcome measures.

Methodology

All patients were treated by the same clinician with indirect composite onlays for the restoration of root filled posterior teeth between January 2008 and February 2010 in a single clinic setting. Primary root canal treatment was performed and onlays fabricated with the indirect method using indirect composite resin. Patients were seen every 4–6 months for maintenance visits according to standard clinic protocols and each patient's individualized maintenance schedule. Tooth and restoration survival were calculated, and the onlays were evaluated in accordance with the modified US Public Health Service (USPHS) criteria.

Results

Thirty‐one premolars and one hundred and fifty‐eight molars (n = 189) of 153 patients were included. The observation period ranged from 24 to 52 months with a median follow‐up time of 37 months. Tooth survival was found to be 100%, whilst the restoration survival was 96.8% and the functional restoration survival 98.9% at the end of the follow‐up period. According to modified USPHS criteria, the A rating had a range of 83.1–100% for all evaluation criteria.

Conclusions

Onlay restorations fabricated with indirect resin can be a viable option for the restoration of root filled teeth.
Evaluation of the root canal shaping ability of two rotary nickel–titanium systems
Authors: Al‐Manei K. K. , Al‐Hadlaq S. M. S.
Published: January 2014

Aim

The aim was to investigate the canal shaping abilities of the twisted file (TF) and GT series X file (GTX) systems.

Methodology

Sixty mesial root canals of mandibular molars with curvatures of 15–50° were divided randomly into two groups of 30 canals each. The teeth were sectioned horizontally at 3, 6 and 9 mm from the apex. Root canals were prepared with TF and GTX files, respectively, and the shaping abilities of the systems were evaluated at three levels (coronal, middle and apical) based on the comparison of pre‐ and post‐instrumentation photographs using AutoCAD software. Preparation time was also assessed. Data from the two groups were compared statistically using the Student's t‐test.

Results

There was no significant difference between the rotary systems in terms of change in root canal cross‐sectional area, root canal transportation, centring ability or minimum dentine thickness. Remaining dentine thickness at the coronal and middle levels was similar in the TF and GTX groups, but GTX instruments left significantly less dentine than TF instruments on the mesial aspects of root canals at the apical level. Root canal preparation with TF instruments required significantly less time than with GTX instruments.

Conclusions

The TF and GTX NiTi rotary instruments showed similar shaping abilities, but root canal preparation was more rapid with the TF than with the GTX system.
A Randomized Controlled Trial Comparing the Effects of Yoga With an Active Control on Ambulatory Blood Pressure in Individuals With Prehypertension and Stage 1 Hypertension
Authors: Hagins Marshall , Rundle Andrew , Consedine Nathan S. , Khalsa Sat Bir S.
Published: January 2014

The purpose of this study was to compare the effects of yoga with an active control (nonaerobic exercise) in individuals with prehypertension and stage 1 hypertension. A randomized clinical trial was performed using two arms: (1) yoga and (2) active control. Primary outcomes were 24‐hour day and night ambulatory systolic and diastolic blood pressures. Within‐group and between‐group analyses were performed using paired t tests and repeated‐measures analysis of variance (time × group), respectively. Eighty‐four participants enrolled, with 68 participants completing the trial. Within‐group analyses found 24‐hour diastolic, night diastolic, and mean arterial pressure all significantly reduced in the yoga group (−3.93, −4.7, −4.23 mm Hg, respectively) but no significant within‐group changes in the active control group. Direct comparisons of the yoga intervention with the control group found a single blood pressure variable (diastolic night) to be significantly different (P=.038). This study has demonstrated that a yoga intervention can lower blood pressure in patients with mild hypertension. Although this study was not adequately powered to show between‐group differences, the size of the yoga‐induced blood pressure reduction appears to justify performing a definitive trial of this intervention to test whether it can provide meaningful therapeutic value for the management of hypertension.
Eliminating the Human Factor in Office Blood Pressure Measurement
Authors: Myers Martin G.
Published: January 2014

Factors related to the physician/nurse and patient and their interaction are potential sources of error in manual office blood pressure (MOBP). The use of automated sphygmomanometers to record blood pressure (BP) with the patient alone reduces measurement error and minimizes anxiety‐related increases in BP, thus eliminating the “white‐coat” response. Comparative studies have shown the cut‐point for a normal automated office BP (AOBP), awake ambulatory BP, and home BP (<135/85 mmHg) to be similar, providing the patient does not rest for a prolonged period before the first AOBP reading, as recommended for MOBP measurement. AOBP should now replace MOBP in routine clinical practice.
Managerial Agency Costs of Socialistic Internal Capital Markets: Empirical Evidence from China
Authors: Wang Jiwei , Ye Kangtao
Published: January 2014

This study provides empirical evidence of managerial agency costs in socialistic internal capital markets. Listed Chinese companies are required to disclose the amount of resources that are reallocated to other firms of the parent company, which provides us with a direct measure of the socialistic subsidization of weak member firms by strong member firms within a business group. We hypothesize that in strong member firms, managerial compensation is less sensitive to firm performance because cross‐subsidization makes it difficult for group CEOs to hold the managers in strong firms accountable for their own firms' performance, and also increases the noise in performance measures. We also hypothesize that socialistic cross‐subsidization results in an increase in managerial agency costs of strong member firms due to the low pay‐performance sensitivity and low incentive to work hard. We document empirical results that are consistent with these two predictions.
A new loss‐of‐function allele 28y reveals a role of ARGONAUTE1 in limiting asymmetric division of stomatal lineage ground cell
Authors: Yang Kezhen , Jiang Min , Le Jie
Published: January 2014

In Arabidopsis thaliana L., stomata are produced through a series of divisions including asymmetric and symmetric divisions. Asymmetric entry division of meristemoid mother cell produces two daughter cells, the smaller meristemoid and the larger sister cell, a stomatal lineage ground cell (SLGC). Stomatal lineage ground cells can differentiate into epidermal pavement cells but have the potential to divide asymmetrically, spacing divisions, to create satellite meristemoids. Peptide ligands and TOO MANY MOUTHS (TMM) and ERECTA family receptors regulate the initiation of stomatal lineages, activity, and orientation of spacing divisions. Here, we reported that a natural mutant 28y displayed an increased stomatal density and index. Using map‐based cloning, we identified mutation in ARGONAUTE1 (AGO1) as the cause of 28y phenotypes. Time‐lapse tracing of stomatal lineage cells reveals that stomatal overproduction in 28y is caused by the excessive asymmetric spacing division of SLGCs. Further genetic results demonstrated that AGO1 acts downstream of TMM and negatively regulates the SPCH transcripts, but in a brassinosteroid‐independent manner. Upregulation of AGAMOUS‐LIKE16 (AGL16) in 28y mutants suggests that AGO1 is required to restrict AGL16‐mediated stomatal spacing divisions, an miRNA pathway in addition to ligand‐receptor signaling modules.
Signaling events during initiation of arbuscular mycorrhizal symbiosis
Authors: Schmitz Alexa M. , Harrison Maria J.
Published: January 2014

Under nutrient‐limiting conditions, plants will enter into symbiosis with arbuscular mycorrhizal (AM) fungi for the enhancement of mineral nutrient acquisition from the surrounding soil. AM fungi live in close, intracellular association with plant roots where they transfer phosphate and nitrogen to the plant in exchange for carbon. They are obligate fungi, relying on their host as their only carbon source. Much has been discovered in the last decade concerning the signaling events during initiation of the AM symbiosis, including the identification of signaling molecules generated by both partners. This signaling occurs through symbiosis‐specific gene products in the host plant, which are indispensable for normal AM development. At the same time, plants have adapted complex mechanisms for avoiding infection by pathogenic fungi, including an innate immune response to general microbial molecules, such as chitin present in fungal cell walls. How it is that AM fungal colonization is maintained without eliciting a defensive response from the host is still uncertain. In this review, we present a summary of the molecular signals and their elicited responses during initiation of the AM symbiosis, including plant immune responses and their suppression.
Nitrate regulates rhizobial and mycorrhizal symbiosis in common bean (Phaseolus vulgaris L.)
Authors: Nanjareddy Kalpana , Blanco Lourdes , Arthikala Manoj‐Kumar , Affantrange Xochitl Alvarado , Sánchez Federico , Lara Miguel
Published: January 2014

Nitrogen‐limited conditions are considered to be a prerequisite for legume‐rhizobial symbiosis, but the effects of nitrate‐rich conditions on symbiotic status remain poorly understood. We addressed this issue by examining rhizobial (Rhizobim tropici) and arbusclar mycorrhizal (Glomus intraradices) symbiosis in Phaseolus vulgaris L. cv. Negro Jamapa under nitrate pre‐incubation and continuous nitrate conditions. Our results indicate that nitrate pre‐incubation, independent of the concentration, did not affect nodule development. However, the continuous supply of nitrate at high concentrations impaired nodule maturation and nodule numbers. Low nitrate conditions, in addition to positively regulating nodule number, biomass, and nitrogenase activity, also extended the span of nitrogen‐fixing activity. By contrast, for arbuscular mycorrhizae, continuous 10 and 50 mmol/L nitrate increased the percent root length colonization, concomitantly reduced arbuscule size, and enhanced ammonia transport without affecting phosphate transport. Therefore, in this manuscript, we have proposed the importance of nitrate as a positive regulator in promoting both rhizobial and mycorrhizal symbiosis in the common bean.
Source and genesis of sulphate and phosphate–sulphate minerals in a quartz‐sandstone cave environment
Authors: Sauro Francesco , Tisato Nicola , De Waele Jo , Bernasconi Stefano M. , Bontognali Tomaso R. R. , Galli Ermanno
Published: January 2014

Gypsum (CaSO4·2H2O), alunite (KAl3(SO4)2(OH)6), and rare phosphate–sulphate sanjuanite Al2(PO4)(SO4)(OH) 9(H2O) and rossiantonite (Al3(PO4)(SO4) 2(OH)2(H2O)14) have recently been identified as secondary mineral deposits in different quartz‐sandstone caves in the Gran Sabana region, Venezuela. Due to the extended time scale required for speleogenesis in the hard and barely soluble quartz‐sandstone lithology, these caves are considered to be as old as 20 to 30 My. The study of these peculiar secondary mineral deposits potentially reveals important insights for understanding the interaction between deep, superficial and atmospheric processes over thousands to perhaps millions of years. In this study, chemical and petrographic analyses of potential host rock sources, sulphur and oxygen isotope ratios, and meteorological, hydrological and geographical data are used to investigate the origin of sulphates and phospho–sulphates. The results suggest that the deposition of sulphates in these caves is not linked to the quartz‐sandstone host rock. Rather, these mineral deposits originate from an external atmospheric sulphate source, with potential contributions of marine non‐sea salt sulphates, terrestrial dimethyl sulphide and microbially reduced H2S from the forests or peatbogs within the watershed. Air currents within the caves are the most plausible means of transport for aerosols, driving the accumulation of sulphates and other secondary minerals in specific locations. Moreover, the studied sulphate minerals often co‐occur with silica speleothems of biological origin. Although this association would suggest a possible biogenic origin for the sulphates as well, direct evidence proving that microbes are involved in their formation is absent. Nonetheless, this study demonstrates that these quartz‐sandstone caves accumulate and preserve allogenic sulphates, playing a yet unrecognized role in the sulphur cycle of tropical environments.
Darkness and gulliver2/phyB mutation decrease the abundance of phosphorylated BZR1 to activate brassinosteroid signaling in Arabidopsis
Authors: Kim Bokyung , Jeong Yu Jeong , Corvalán Claudia , Fujioka Shozo , Cho Seoae , Park Taesung , Choe Sunghwa
Published: January 2014

Light is essential for plant survival; as such, plants flexibly adjust their growth and development to best harvest light energy. Brassinosteroids (BRs), plant growth‐promoting steroid hormones, are essential for this plasticity of development. However, the precise mechanisms underlying BR‐mediated growth under different light conditions remain largely unknown. Here, we show that darkness increases the activity of the BR‐specific transcription factor, BZR1, by decreasing the phosphorylated (inactive) form of BZR1 in a proteasome‐dependent manner. We observed that COP1, a dark‐activated ubiquitin ligase, captures and degrades the inactive form of BZR1. In support of this, BZR1 is abundant in the cop1‐4 mutant. The removal of phosphorylated BZR1 in darkness increases the ratio of dephosphorylated to phosphorylated forms of BZR1, thus increasing the chance of active homodimers forming between dephosphorylated BZR1 proteins. Furthermore, a transcriptome analysis revealed the identity of genes that are likely to contribute to the differential growth of hypocotyls in light conditions. Transgenic misexpression of three genes under the 35S promoter in light conditions resulted in elongated petioles and hypocotyls. Our results suggest that light conditions directly control BR signaling by modulating BZR1 stability, and consequently by establishing light‐dependent patterns of hypocotyl growth in Arabidopsis.
Effect of phosphate‐based seed priming on strigolactone production and Striga hermonthica infection in cereals
Authors: Jamil M , Charnikhova T , Verstappen F , Ali Z , Wainwright H , Bouwmeester H J
Published: January 2014

Strigolactones, plant‐secreted underground signalling molecules, play an important role in agricultural ecosystems, because they mediate the interaction of crops with symbiotic AM fungi and parasitic weeds like Striga hermonthica. Cereal host plants secret these signalling molecules particularly under nutrient‐deficient conditions and especially when phosphate (P) is limiting. The objective of the present study was to see the potential of P seed priming for S. hermonthica management in cereals in relation to strigolactone production. It has been demonstrated that P fertiliser application down‐regulates the production of these signalling molecules in the rhizosphere, which results in lower S. hermonthica infection of cereals. The laboratory study showed maximum production of strigolactones from dry and water‐soaked seeds, while seed soaking in P solution reduced their production. Similarly, maximum S. hermonthica infection was observed under control treatments with dry sowing or water soaking, while P seed soaking decreased S. hermonthica germination, emergence and dry biomass in all cereal crops. Our study shows that P seed priming resulted in lower exudation of strigolactones, which induced less S. hermonthica seeds germination and hence may lead to lower S. hermonthica infection. P‐based seed priming could prove to be an effective and affordable strategy to reduce S. hermonthica infection in cereals. Further research for practical field application is needed.
Distribution, Diversity, and Activities of Sulfur Dioxygenases in Heterotrophic Bacteria
Authors: Liu Honglei , Xin Yufeng , Xun Luying
Published: January 2014

Sulfur oxidation by chemolithotrophic bacteria is well known; however, sulfur oxidation by heterotrophic bacteria is often ignored. Sulfur dioxygenases (SDOs) (EC 1.13.11.18) were originally found in the cell extracts of some chemolithotrophic bacteria as glutathione (GSH)-dependent sulfur dioxygenases. GSH spontaneously reacts with elemental sulfur to generate glutathione persulfide (GSSH), and SDOs oxidize GSSH to sulfite and GSH. However, SDOs have not been characterized for bacteria, including chemolithotrophs. The gene coding for human SDO (human ETHE1 [hETHE1]) in mitochondria was discovered because its mutations lead to a hereditary human disease, ethylmalonic encephalopathy. Using sequence analysis and activity assays, we discovered three subgroups of bacterial SDOs in the proteobacteria and cyanobacteria. Ten selected SDO genes were cloned and expressed in
Escherichia coli
, and the recombinant proteins were purified. The SDOs used Fe
2+
for catalysis and displayed considerable variations in specific activities. The wide distribution of SDO genes reveals the likely source of the hETHE1 gene and highlights the potential of sulfur oxidation by heterotrophic bacteria.
Watershed-Scale Fungal Community Characterization along a pH Gradient in a Subsurface Environment Cocontaminated with Uranium and Nitrate
Authors: Jasrotia Puja , Green Stefan J. , Canion Andy , Overholt Will A. , Prakash Om , Wafula Denis , Hubbard Daniela , Watson David B. , Schadt Christopher W. , Brooks Scott C. , Kostka Joel E.
Published: January 2014

The objective of this study was to characterize fungal communities in a subsurface environment cocontaminated with uranium and nitrate at the watershed scale and to determine the potential contribution of fungi to contaminant transformation (nitrate attenuation). The abundance, distribution, and diversity of fungi in subsurface groundwater samples were determined using quantitative and semiquantitative molecular techniques, including quantitative PCR of eukaryotic small-subunit rRNA genes and pyrosequencing of fungal internal transcribed spacer (ITS) regions. Potential bacterial and fungal denitrification was assessed in sediment-groundwater slurries amended with antimicrobial compounds and in fungal pure cultures isolated from the subsurface. Our results demonstrate that subsurface fungal communities are dominated by members of the phylum
Ascomycota
, and a pronounced shift in fungal community composition occurs across the groundwater pH gradient at the field site, with lower diversity observed under acidic (pH <4.5) conditions. Fungal isolates recovered from subsurface sediments, including cultures of the genus
Coniochaeta
, which were detected in abundance in pyrosequence libraries of site groundwater samples, were shown to reduce nitrate to nitrous oxide. Denitrifying fungal isolates recovered from the site were classified and found to be distributed broadly within the phylum
Ascomycota
and within a single genus of the
Basidiomycota
. Potential denitrification rate assays with sediment-groundwater slurries showed the potential for subsurface fungi to reduce nitrate to nitrous oxide under
in situ
acidic pH conditions.
Cas9-Based Tools for Targeted Genome Editing and Transcriptional Control
Authors: Xu Tao , Li Yongchao , Van Nostrand Joy D. , He Zhili , Zhou Jizhong
Published: January 2014

Development of tools for targeted genome editing and regulation of gene expression has significantly expanded our ability to elucidate the mechanisms of interesting biological phenomena and to engineer desirable biological systems. Recent rapid progress in the study of a clustered, regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated (Cas) protein system in bacteria has facilitated the development of newly facile and programmable platforms for genome editing and transcriptional control in a sequence-specific manner. The core RNA-guided Cas9 endonuclease in the type II CRISPR system has been harnessed to realize gene mutation and DNA deletion and insertion, as well as transcriptional activation and repression, with multiplex targeting ability, just by customizing 20-nucleotide RNA components. Here we describe the molecular basis of the type II CRISPR/Cas system and summarize applications and factors affecting its utilization in model organisms. We also discuss the advantages and disadvantages of Cas9-based tools in comparison with widely used customizable tools, such as Zinc finger nucleases and transcription activator-like effector nucleases.
Development of an Enzyme-Linked Immunosorbent Spot Assay To Measure Serum-Neutralizing Antibodies against Coxsackievirus B3
Authors: Yang Lisheng , He Delei , Tang Min , Li Zhiqun , Liu Che , Xu Longfa , Chen Yixin , Du Hailian , Zhao Qinjian , Zhang Jun , Cheng Tong , Xia Ningshao
Published: January 2014

Coxsackievirus B3 (CVB3) is the most common pathogen that induces acute and chronic viral myocarditis in children. The cytopathic effect (CPE)-based neutralization test (Nt-CPE) and the plaque reduction neutralization test (PRNT) are the most common methods for measuring neutralizing antibody titers against CVB3 in blood serum samples. However, these two methods are inefficient for CVB3 vaccine clinical trials, which require the testing of a large number of serum specimens. In this study, we developed an efficient neutralization test based on the enzyme-linked immunospot (Nt-ELISPOT) assay for measuring CVB3-neutralizing antibodies. This modified ELISPOT assay was based on the use of a monoclonal antibody against the viral capsid protein VP1 to detect the cells that are infected with CVB3, which, after immunoperoxidase staining, are counted as spots using an automated ELISPOT analyzer. Using the modified ELISPOT assay, we characterized the infection kinetics of CVB3 and divided the infection process of CVB3 on a cluster of cells into four phases. The stability of the Nt-ELISPOT was then evaluated. We found that over a wide range of infectious doses (102to 106.5× 50% tissue culture infectious dose [TCID50] per well), the neutralizing titers of the sera were steady as long as they were tested during the log phase or the first half of the stationary phase of growth of the spots. We successfully shortened the testing period from 7 days to approximately 20 h. We also found that there was a good correlation (R2= 0.9462) between the Nt-ELISPOT and the Nt-CPE assays. Overall, the Nt-ELISPOT assay is a reliable and efficient method for measuring neutralizing antibodies in serum.
Key Role of Effector Memory CD4+T Lymphocytes in a Short-Incubation Heparin-Binding Hemagglutinin Gamma Interferon Release Assay for the Detection of Latent Tuberculosis
Authors: Wyndham-Thomas Chloé , Corbière Véronique , Dirix Violette , Smits Kaatje , Domont Fanny , Libin Myriam , Loyens Marc , Locht Camille , Mascart Françoise
Published: January 2014

The treatment of latent tuberculosis infection (LTBI) in target populations is one of the current WHO strategies for preventing active tuberculosis (TB) infection and reducing theMycobacterium tuberculosisreservoir. Therefore, powerful LTBI screening tools are indispensable. A gamma interferon release assay (IGRA) in response to the stimulation of peripheral blood mononuclear cells by the latency antigen native heparin-binding hemagglutinin (nHBHA-IGRA) has proven its potential for this purpose. We have evaluated its possible optimization through a reduction of incubation time from 96 to 24 h, while compensating for this by adding interleukin 7 (IL-7) to the medium. We have also investigated the phenotypes of the gamma interferon (IFN-γ)-producing cells after both short and long incubation times. One hundred thirty-one nonimmunocompromised patients were recruited from 3 Brussels-based university hospitals. They were divided into 1 of 4 subgroups according to theirM. tuberculosisinfection status (LTBI, TB infection, undeterminedM. tuberculosisinfection status, and noninfected controls). The novel 24-h nHBHA-IGRA was performed for all subjects, and a simultaneous 96-h classical HBHA-IGRA was performed for 79 individuals. The results showed a good correlation between the two tests, and the novel 24-h nHBHA-IGRA maintained the principal advantages of the classical test, namely, a high specificity for LTBI diagnosis, an absence of interference ofMycobacterium bovisBCG vaccination during infancy, and a relative discrimination between LTBI and TB infection. Whereas the commercialized IGRAs show a greater sensitivity for recent than for remoteM. tuberculosisinfections, the 24-h nHBHA-IGRA appears to have comparable diagnostic powers for recent and remote LTBI. The IFN-γ detected by the 24-h nHBHA-IGRA was mainly secreted by effector memory CD4+T lymphocytes, a finding suggestive of continuous HBHA presentation during latency.
Gamma Interferon Immunospot Assay of Pleural Effusion Mononuclear Cells for Diagnosis of Tuberculous Pleurisy
Authors: Liao Mingfeng , Yang Qianting , Zhang Jieyun , Zhang Mingxia , Deng Qunyi , Liu Haiying , Graner Michael W. , Kornfeld Hardy , Zhou Boping , Chen Xinchun
Published: January 2014

Diagnosis of tuberculous pleurisy remains a challenge in the clinic. In this study, we evaluated the usefulness of a previously developedMycobacterium tuberculosisantigen-specific gamma interferon enzyme-linked immunospot (ELISPOT) assay in the diagnosis of tuberculous pleurisy by testing a cohort of 352 patients with pleural effusion. We found thatM. tuberculosisantigen-specific gamma interferon-producing cells were enriched four to five times in pleural fluid compared with their levels in peripheral blood from patients with tuberuclous pleurisy assayed in parallel. The sensitivity, specificity, positive predictive value, and negative predictive value of the pleural fluid mononuclear cell ELISPOT assay for the diagnosis of tuberculous pleurisy were 95.7%, 100%, 100%, and 81.0%, respectively. In comparison, the sensitivity and specificity of the ELISPOT assay using peripheral blood mononuclear cells were 78.3% and 86.3%, respectively. The sensitivity and specificity of the pleural fluid adenosine deaminase activity test were 55.5% and 86.3%, respectively. These results demonstrate that theM. tuberculosisantigen-specific ELISPOT assay performed on pleural fluid mononuclear cells provides an accurate, rapid diagnosis of tuberculous pleurisy.