Integrated intracellular organization and its variations in human iPS cells.

Understanding how a subset of expressed genes dictates cellular phenotype is a considerable challenge owing to the large numbers of molecules involved, their combinatorics and the plethora of cellular behaviours that they determine1,2. Here we reduced this complexity by focusing on cellular organization-a key readout and driver of cell behaviour3,4-at the level of major cellular structures that represent distinct organelles and functional machines, and generated the WTC-11 hiPSC Single-Cell Image Dataset v1, which contains more than 200,000 live cells in 3D, spanning 25 key cellular structures. The scale and quality of this dataset permitted the creation of a generalizable analysis framework to convert raw image data of cells and their structures into dimensionally reduced, quantitative measurements that can be interpreted by humans, and to facilitate data exploration. This framework embraces the vast cell-to-cell variability that is observed within a normal population, facilitates the integration of cell-by-cell structural data and allows quantitative analyses of distinct, separable aspects of organization within and across different cell populations. We found that the integrated intracellular organization of interphase cells was robust to the wide range of variation in cell shape in the population; that the average locations of some structures became polarized in cells at the edges of colonies while maintaining the 'wiring' of their interactions with other structures; and that, by contrast, changes in the location of structures during early mitotic reorganization were accompanied by changes in their wiring.

Agricultural insect pests as models for studying stress-induced evolutionary processes.

Agricultural insect pests (AIPs) are widely successful in adapting to natural and anthropogenic stressors, repeatedly overcoming population bottlenecks and acquiring resistance to intensive management practices. Although they have been largely overlooked in evolutionary studies, AIPs are ideal systems for understanding rapid adaptation under novel environmental conditions. Researchers have identified several genomic mechanisms that likely contribute to adaptive stress responses, including positive selection on de novo mutations, polygenic selection on standing allelic variation and phenotypic plasticity (e.g., hormesis). However, new theory suggests that stress itself may induce epigenetic modifications, which may confer heritable physiological changes (i.e., stress-resistant phenotypes). In this perspective, we discuss how environmental stress from agricultural management generates the epigenetic and genetic modifications that are associated with rapid adaptation in AIPs. We summarise existing evidence for stress-induced evolutionary processes in the context of insecticide resistance. Ultimately, we propose that studying AIPs offers new opportunities and resources for advancing our knowledge of stress-induced evolution.

Near-total mandibular reconstruction following osteoradionecrosis with double scapula tip free flap: A case report.

Near-total mandibular reconstruction poses many challenges to reconstructive surgeons. The purpose of this article is to present a challenging case in a patient with osteoradionecrosis of the mandible requiring a near-total mandibular reconstruction using bilateral scapula tip free tissue reconstruction. A 68-year-old African-American male with a history of T2N0M0 squamous cell carcinoma of the tonsil presented with advanced stage osteoradionecrosis of the mandible. Reconstruction was planned using 3D Systems (Denver, CO), mandibular osteotomies were planned inferior to the sigmoid notch on the ascending rami. Neither fibula flap was amenable for harvesting due to poor vasculature of the patient's lower extremities, and bilateral scapula tip free flaps were subsequently planned. The post-operative course was complicated by venous congestion in the right scapula flap which required revision to the venous anastomosis on POD 1. The patient had intraoral breakdown that required debridement in the operating room and application of a cellular matrix. The patient fully recovered from the acute surgery and was discharged home without a tracheostomy. At the last follow up visit, the patient was taking 100% of diet peroral and had no signs of oral incompetence, mental projection was satisfactory, and the ability to verbally communicate was unimpaired. We report a complex case of near-total mandibular reconstruction using simultaneous bilateral scapula tip free flaps. While we do not advocate simultaneous bilateral scapula tip free flaps as the standard of care for large mandibulectomy defects, it may be considered for patients in which traditional osseous free flaps are not available.

Chemotherapy-related amenorrhea (CRA) after adjuvant ado-trastuzumab emtansine (T-DM1) compared to paclitaxel in combination with trastuzumab (TH) (TBCRC033: ATEMPT Trial).

PURPOSE: Chemotherapy-related amenorrhea (CRA) is a surrogate for ovarian toxicity and associated risk of infertility and premature menopause. Here, we compare CRA rate with paclitaxel (T)-trastuzumab (H) to that with ado-trastuzumab emtansine (T-DM1). METHODS: Patients with T1N0 HER2 + early-stage breast cancer (eBC) enrolled on the ATEMPT trial and were randomized 3:1 to T-DM1 3.6 mg/kg IV every (q) 3 weeks (w) × 17 vs. T 80 mg/m2 with H IV qw × 12 (4 mg/kg load → 2 mg/kg), followed by H (6 mg/kg IV q3w × 13). Enrollees who self-reported as premenopausal were asked to complete menstrual surveys at baseline and every 6-12 months for 60 months. 18-month CRA (no periods reported during prior 6 months on 18-month survey) was the primary endpoint of this analysis. RESULTS: Of 512 ATEMPT enrollees, 123 who began protocol therapy and answered baseline and at least one follow-up menstrual survey were premenopausal at enrollment. 76 had menstrual data available at 18 months without having received a gonadotropin-releasing hormone agonist or undergone hysterectomy and/or oophorectomy. Median age was 45 (range 23-53) among 18 who had received TH and 46 (range 34-54) among 58 who had received T-DM1. The 18-month rate of CRA was 50% after TH and 24% after T-DM1 (p = 0.045). CONCLUSION: Amenorrhea at 18 months was less likely in recipients of adjuvant T-DM1 than TH. Future studies are needed to understand how T-DM1 impacts risk of infertility and permanent menopause, and to assess amenorrhea rates when T-DM1 is administered after standard HER2-directed chemotherapy regimens.

Schizophrenia syndrome due to C9ORF72 mutation case report: a cautionary tale and role of hybrid brain imaging!

BACKGROUND: Frontal variant frontotemporal dementia is a common cause of presenile dementia. A hexanucleotide expansion on chromosome 9 has recently been recognized as the most common genetic mutation cause of this illness. This sub-type tends to present psychiatrically with psychosis being a common presenting symptom before the onset of cognitive changes or brain atrophy. A few case series have been published describing the prominence of early psychotic symptoms, and lack of clear brain atrophy on clinical brain imaging imposing a challenge in reaching early accurate diagnosis. In this report, we present a case whereby the diagnosis of Schizophrenia syndrome was made and the patient was treated for years with multiple interventions for that syndrome before reaching the accurate diagnosis of Frontal variant frontotemporal dementia due to hexanucleotide expansion on chromosome 9. This diagnosis was confirmed after genetic testing and findings on a hybrid Positron Emission Tomography/Magnetic Resonance Imaging scanning. A 60-year-old female diagnosed with schizophrenia at age 50 after presenting with delusions and hallucinations, which proved to be refractor to several lines of pharmacological and non-pharmacological interventions including electroconvulsive therapy. Patient had a history of post-partum psychosis in her 20s. She was referred to cognitive neurology due to progressive decline in function. While clinical structural brain imaging data were not adequate to support an alternative neurological diagnosis, careful inquiry elicited a history of psychotic illness followed by progressive decline in a sister. Genetic testing confirmed hexanucleotide expansion on chromosome 9 mutation. The patient was offered a state-of-the-art FD-Glucose Positron Emission Tomography/Magnetic Resonance Imaging scan available at our centre. While volumetric Magnetic Resonance Imaging scan did not show volume loss in frontotemporal areas, the hybrid scan showed regionally specific deficit in FD-Glucose Positron Emission Tomography affecting medial superior frontal, insula, inferior temporal, thalamus, and anterior cingulate cortex consistent with behavioral variant frontotemporal dementia. CONCLUSIONS: This case highlights the importance of considering Frontal variant frontotemporal dementia due to hexanucleotide expansion on chromosome 9 when facing relatively late-onset, refractory schizophrenia-like syndrome. Careful history from all available sources to elicit family history of similar presentation is very important. Genetic testing and functional brain imaging can aid in confirming the diagnosis and potentially streamlining the management of these cases.

Parent and staff attitudes towards in-hospital opportunistic vaccination.

OBJECTIVES: Recent trends of 'vaccine hesitancy' have resulted in calls for public health campaigns to improve immunisation uptake to World Health Organisation (WHO) targets. One potential strategy to improve uptake is to offer opportunistic vaccination to those hospital in-patients who have missed them. We aimed to evaluate parental and staff attitudes about introducing such a service for hospitalised children. STUDY DESIGN: Cross sectional questionnaire-based design. METHODS: We developed and distributed a questionnaire for parents/guardians of paediatric inpatients aged 5 years and under, and a questionnaire for frontline paediatric staff (including medical, nursing and allied health professionals). Vaccination rates were assessed through discussion with parents and by reviewing the personal child health record. RESULTS: One-hundred families and 100 paediatric staff participated. Local vaccination rates were significantly below the WHO target (P < 0.001), particularly for the Bacille Calmette-Guerine (BCG) vaccination (P = 0.001). Both parents (89/100, 89%) and staff (87/100, 87%) regarded inpatient opportunistic vaccination acceptable. Parents of children with chronic disease reported a potentially higher rate of missed vaccinations, stating reasons of frequent illness and inpatient stays. The majority of staff (81/95, 85.3%) would be willing to support inpatient vaccination if appropriately trained. A significant minority had reservations. CONCLUSIONS: Opportunistic vaccination is a strategy deemed acceptable by the majority of parents and staff. Children with chronic disease would especially benefit from opportunistic inpatient immunisation. In order to facilitate this, improved digital access to primary care vaccination records and investment in staff training, education and support would be required.

Development and Implementation of a Bedside Peripherally Inserted Central Catheter Service in a PICU.

OBJECTIVES: To create a bedside peripherally inserted central catheter service to increase placement of bedside peripherally inserted central catheter in PICU patients. DESIGN: Two-phase observational, pre-post design. SETTING: Single-center quaternary noncardiac PICU. PATIENTS: All patients admitted to the PICU. INTERVENTIONS: From June 1, 2015, to May 31, 2017, a bedside peripherally inserted central catheter service team was created (phase I) and expanded (phase II) as part of a quality improvement initiative. A multidisciplinary team developed a PICU peripherally inserted central catheter evaluation tool to identify amenable patients and to suggest location and provider for procedure performance. Outcome, process, and balancing metrics were evaluated. MEASUREMENTS AND MAIN RESULTS: Bedside peripherally inserted central catheter service placed 130 of 493 peripherally inserted central catheter (26%) resulting in 2,447 hospital central catheter days. A shift in bedside peripherally inserted central catheter centerline proportion occurred during both phases. Median time from order to catheter placement was reduced for peripherally inserted central catheters placed by bedside peripherally inserted central catheter service compared with placement in interventional radiology (6 hr [interquartile range, 2-23 hr] vs 34 hr [interquartile range, 19-61 hr]; p < 0.001). Successful access was achieved by bedside peripherally inserted central catheter service providers in 96% of patients with central tip position in 97%. Bedside peripherally inserted central catheter service central line-associated bloodstream infection and venous thromboembolism rates were similar to rates for peripherally inserted central catheters placed in interventional radiology (all central line-associated bloodstream infection, 1.23 vs 2.18; p = 0.37 and venous thromboembolism, 1.63 vs 1.57; p = 0.91). Peripherally inserted central catheters in PICU patients had reduced in-hospital venous thromboembolism rate compared with PICU temporary catheter in PICU rate (1.59 vs 5.36; p < 0.001). CONCLUSIONS: Bedside peripherally inserted central catheter service implementation increased bedside peripherally inserted central catheter placement and employed a patient-centered and timely process. Balancing metrics including central line-associated bloodstream infection and venous thromboembolism rates were not significantly different between peripherally inserted central catheters placed by bedside peripherally inserted central catheter service and those placed in interventional radiology.

A systematic surveillance programme for infectious salmon anaemia virus supports its absence in the Pacific Northwest of the United States.

In response to reported findings of infectious salmon anaemia virus (ISAV) in British Columbia (BC), Canada, in 2011, U.S. national, state and tribal fisheries managers and fish health specialists developed and implemented a collaborative ISAV surveillance plan for the Pacific Northwest region of the United States. Accordingly, over a 3-1/2-year period, 4,962 salmonids were sampled and successfully tested by real-time reverse-transcription PCR. The sample set included multiple tissues from free-ranging Pacific salmonids from coastal regions of Alaska and Washington and farmed Atlantic salmon (Salmo salar L.) from Washington, all representing fish exposed to marine environments. The survey design targeted physiologically compromised or moribund animals more vulnerable to infection as well as species considered susceptible to ISAV. Samples were handled with a documented chain of custody and testing protocols, and criteria for interpretation of test results were defined in advance. All 4,962 completed tests were negative for ISAV RNA. Results of this surveillance effort provide sound evidence to support the absence of ISAV in represented populations of free-ranging and marine-farmed salmonids on the northwest coast of the United States.

Microscale Measurement and Visualization of Sulfide δ34S Using Photographic Film Sulfide Capture Coupled with Laser Ablation Multicollector Inductively Coupled Plasma Mass Spectrometry.

Measurements of the isotopic composition of sulfate and sulfide have been essential to uncovering the microbial and geochemical processes that drive Earth's sulfur cycle. These processes routinely operate over submillimeter spatial scales in anaerobic environments, necessitating sulfur isotopic measurement techniques that can identify isotopic variability over equivalently small scales. Here we present a new method for small-scale (102 µm) measurements of δ34S using black and white photographic film sulfide capture coupled with δ34S determination using laser ablation multicollector inductively coupled plasma mass spectrometry. We find that the method enables measurement of δ34S for aqueous sulfide in natural waters at high spatial resolution (<1 mm2) with reasonable accuracy (<0.9‰, 2σ) and external precision (<0.8‰, 2σ), and across an environmentally relevant concentration range (0.01-20 mmol L-1). A concentration-dependent correction is required during data analysis to achieve these specifications, which corrects δ34S measurements for mixing with sulfur native to the film material and fractionation due to Ag2S precipitation from aqueous sulfide. We demonstrate the applicability of our technique using an anaerobic incubation of seawater and sediment, mapping two-dimensional δ34Ssulfide at a 535 µm × 535 µm spatial scale, with internal precisions of 1.4‰ to 1.5‰. Our method offers the benefits of minimal sample preparation and common availability of sampling material (black and white photographic film), while retaining the necessary precision to identify sulfide δ34S variability and isotopic fractionations at high ambient sulfate and with high spatial resolutions in sulfidic environments.

Root hairs aid soil penetration by anchoring the root surface to pore walls.

The physical role of root hairs in anchoring the root tip during soil penetration was examined. Experiments using a hairless maize mutant (Zea mays: rth3-3) and its wild-type counterpart measured the anchorage force between the primary root of maize and the soil to determine whether root hairs enabled seedling roots in artificial biopores to penetrate sandy loam soil (dry bulk density 1.0-1.5g cm(-3)). Time-lapse imaging was used to analyse root and seedling displacements in soil adjacent to a transparent Perspex interface. Peak anchorage forces were up to five times greater (2.5N cf. 0.5N) for wild-type roots than for hairless mutants in 1.2g cm(-3) soil. Root hair anchorage enabled better soil penetration for 1.0 or 1.2g cm(-3) soil, but there was no significant advantage of root hairs in the densest soil (1.5g cm(-3)). The anchorage force was insufficient to allow root penetration of the denser soil, probably because of less root hair penetration into pore walls and, consequently, poorer adhesion between the root hairs and the pore walls. Hairless seedlings took 33h to anchor themselves compared with 16h for wild-type roots in 1.2g cm(-3) soil. Caryopses were often pushed several millimetres out of the soil before the roots became anchored and hairless roots often never became anchored securely.The physical role of root hairs in anchoring the root tip may be important in loose seed beds above more compact soil layers and may also assist root tips to emerge from biopores and penetrate the bulk soil.

Improving intercropping: a synthesis of research in agronomy, plant physiology and ecology.

Intercropping is a farming practice involving two or more crop species, or genotypes, growing together and coexisting for a time. On the fringes of modern intensive agriculture, intercropping is important in many subsistence or low-input/resource-limited agricultural systems. By allowing genuine yield gains without increased inputs, or greater stability of yield with decreased inputs, intercropping could be one route to delivering 'sustainable intensification'. We discuss how recent knowledge from agronomy, plant physiology and ecology can be combined with the aim of improving intercropping systems. Recent advances in agronomy and plant physiology include better understanding of the mechanisms of interactions between crop genotypes and species ­ for example, enhanced resource availability through niche complementarity. Ecological advances include better understanding of the context-dependency of interactions, the mechanisms behind disease and pest avoidance, the links between above- and below-ground systems, and the role of microtopographic variation in coexistence. This improved understanding can guide approaches for improving intercropping systems, including breeding crops for intercropping. Although such advances can help to improve intercropping systems, we suggest that other topics also need addressing. These include better assessment of the wider benefits of intercropping in terms of multiple ecosystem services, collaboration with agricultural engineering, and more effective interdisciplinary research.

Temporal evolution and variability of dissolved inorganic nitrogen in beach pore water revealed using radon residence times.

We coupled measurements of beach pore water residence time, determined using the radioisotopic tracer (222)Rn, with dissolved carbon and nitrogen chemistry to identify the temporal evolution and variability of dissolved inorganic nitrogen (DIN) concentrations in beach pore water along the Santa Barbara, California coastline. Pore water dissolved organic carbon (DOC) and total dissolved nitrogen (TDN) ratios (DOC:TDN) were negative exponentially correlated with residence time. Mean pore water residence times were positively correlated with tidal amplitudes, and ranged from 4.4 to 6.4 days. We used this range in mean residence times to model radon residence time distributions (RTDs), and integrated them with modeled DIN vs residence time relationships (DIN-temporal evolution, or DIN-te curves) to derive volume-weighted mean (VWM) DIN concentrations. We observed 1.2-fold and 5.2-fold differences (20% and 420% increases) in VWM DIN concentrations over the range in modeled RTDs and DIN-te curves, respectively, and a maximum 6.4-fold difference (540% increase) in VWM DIN concentrations for an interactive shift in the RTD and the DIN-te curve. Our study suggests that accounting for temporal variability in the RTD and DIN concentration of pore water is necessary to obtain more accurate estimates of DIN delivery to coastal oceans.

Floating-Harbor syndrome with chorioretinal colobomas.

BACKGROUND: We present a case of a child with Floating-Harbor Syndrome (FHS) with bilateral chorioretinal coloboma (CC). To the best of our knowledge, this is the first case report of this association. Floating- Harbor syndrome is an extremely rare autosomal dominant genetic disorder with approximately 100 cases reported. It is characterized by a series of atypical features that include short stature with delayed bone age, low birth weight, skeletal anomalies, delayed speech development, and dysmorphic facial characteristics that typically portray a triangular face, deep-set eyes, long eyelashes, and prominent nose. MATERIALS AND METHODS: Our patient was examined by a pediatric ophthalmologist for the time at age of 7. Visual acuity, optical coherence tomography (OCT) and Optos imaging were collected on every visit. The patient had whole genome sequencing ordered by a pediatric geneticist to confirm Floating-Harbor syndrome. RESULTS: We present the patient's OCT and Optos images that illustrate the location of the patient's inferior chorioretinal coloboma in both eyes. The whole genome sequencing report collected revealed a heterozygous de novo pathogenic variant in the SRCAP gene, consistent with a Floating-Harbor syndrome diagnosis in the literature. DISCUSSION: Both genetic and systemic findings are consistent with the diagnosis of Floating-Harbor syndrome in our patient. Rubenstein-Taybi and Floating-Harbor syndrome share a similarity in molecular and physical manifestations, but because of the prevalence in Rubenstein-Taybi diagnoses, it is a syndromic condition that includes coloboma and frequently associated with each other. Therefore, a retinal exam should become part of the standard protocol for those with FHS, as proper diagnosis, examination and treatment can prevent irreversible retinal damage.

Enhancing nasal endoscopy: Classification, detection, and segmentation of anatomic landmarks using a convolutional neural network.

KEY POINTS: A convolutional neural network (CNN)-based model can accurately localize and segment turbinates in images obtained during nasal endoscopy (NE). This model represents a starting point for algorithms that comprehensively interpret NE findings.

Features of Importance in Nasal Endoscopy: Deriving a Meaningful Framework.

OBJECTIVE: Critical components of the nasal endoscopic examination have not been definitively established for either the normal examination or for clinical disorders. This study aimed to identify concordance among rhinologists regarding the importance of examination findings for various nasal pathologies. STUDY DESIGN: A consortium of 19 expert rhinologists across the United States was asked to rank the importance of findings on nasal endoscopy for 5 different sinonasal symptom presentations. SETTING: An online questionnaire was distributed in July 2023. METHODS: The questionnaire utilized JotForm® software and featured 5 cases with a set of 4 identical questions per case, each covering a common indication for nasal endoscopy. Rankings were synthesized into Normalized Attention Scores (NASs) and Weighted Normalized Attention Scores (W-NASs) to represent the perceived importance of each feature, scaled from 0 to 1. RESULTS: General concordance was found for examination findings on nasal endoscopy within each case. The perceived features of importance differed between cases based on clinical presentation. For instance, in evaluating postnasal drip, the middle meatus was selected as the most important structure to examine (NAS, 0.73), with mucus selected as the most important abnormal finding (W-NAS, 0.66). The primary feature of interest for mucus was whether it was purulent or not (W-NAS, 0.67). Similar analyses were performed for features in each case. CONCLUSION: The implicit framework existing among rhinologists may help standardize examinations and improve diagnostic accuracy, augment the instruction of trainees, and inform the development of artificially intelligent algorithms to enhance clinical decision-making during nasal endoscopy.

Root-soil friction: quantification provides evidence for measurable benefits for manipulation of root-tip traits.

To penetrate soil, a root requires pressure both to expand the cavity it is to occupy, σn , and to overcome root-soil friction, σf . Difficulties in estimating these two pressures independently have limited our ability to estimate the coefficient of soil-root friction, µsr . We used a rotated penetrometer probe, of similar dimensions to a root, and for the first time entering the soil at a similar rate to a root tip, to estimate σn . Separately we measured root penetration resistance (PR) Qr . Root PR was between two to four times σn . We estimated that the coefficient of root-soil friction (µsr ) was 0.21-0.26, based on the geometry of the root tip. This is slightly larger than the 0.05-0.15 characteristic of boundary lubricants. Scanning electron microscopy showed that turgid border cells lined the root channel, supporting our hypothesis that the lubricant consisted of mucilage sandwiched between border cells and the surface of the root cap and epidermis. This cell-cell lubrication greatly decreased the friction that would otherwise be experienced had the surface of the root proper slid directly past unlubricated soil particles. Because root-soil friction can be a substantial component of root PR, successful manipulation of friction represents a promising opportunity for improving plant performance.

The Arabidopsis thaliana Myo-inositol 1-phosphate synthase1 gene is required for Myo-inositol synthesis and suppression of cell death.

l-myo-inositol 1-phosphate synthase (MIPS; EC 5.5.1.4) catalyzes the rate-limiting step in the synthesis of myo-inositol, a critical compound in the cell. Plants contain multiple MIPS genes, which encode highly similar enzymes. We characterized the expression patterns of the three MIPS genes in Arabidopsis thaliana and found that MIPS1 is expressed in most cell types and developmental stages, while MIPS2 and MIPS3 are mainly restricted to vascular or related tissues. MIPS1, but not MIPS2 or MIPS3, is required for seed development, for physiological responses to salt and abscisic acid, and to suppress cell death. Specifically, a loss in MIPS1 resulted in smaller plants with curly leaves and spontaneous production of lesions. The mips1 mutants have lower myo-inositol, ascorbic acid, and phosphatidylinositol levels, while basal levels of inositol (1,4,5)P(3) are not altered in mips1 mutants. Furthermore, mips1 mutants exhibited elevated levels of ceramides, sphingolipid precursors associated with cell death, and were complemented by a MIPS1-green fluorescent protein (GFP) fusion construct. MIPS1-, MIPS2-, and MIPS3-GFP each localized to the cytoplasm. Thus, MIPS1 has a significant impact on myo-inositol levels that is critical for maintaining levels of ascorbic acid, phosphatidylinositol, and ceramides that regulate growth, development, and cell death.

Ecological divergence and speciation between lemur (Eulemur) sister species in Madagascar.

Understanding ecological niche evolution over evolutionary timescales is crucial to elucidating the biogeographic history of organisms. Here, we used, for the first time, climate-based ecological niche models (ENMs) to test hypotheses about ecological divergence and speciation processes between sister species pairs of lemurs (genus Eulemur) in Madagascar. We produced ENMs for eight species, all of which had significant validation support. Among the four sister species pairs, we found nonequivalent niches between sisters, varying degrees of niche overlap in ecological and geographic space, and support for multiple divergence processes. Specifically, three sister-pair comparisons supported the null model that niches are no more divergent than the available background region. These findings are consistent with an allopatric speciation model, and for two sister pairs (E. collaris-E. cinereiceps and E. rufus-E. rufifrons), a riverine barrier has been previously proposed for driving allopatric speciation. However, for the fourth sister pair E. flavifrons-E. macaco, we found support for significant niche divergence, and consistent with their parapatric distribution on an ecotone and the lack of obvious geographic barriers, these findings most strongly support a parapatric model of speciation. These analyses thus suggest that various speciation processes have led to diversification among closely related Eulemur species.

Matching roots to their environment.

BACKGROUND: Plants form the base of the terrestrial food chain and provide medicines, fuel, fibre and industrial materials to humans. Vascular land plants rely on their roots to acquire the water and mineral elements necessary for their survival in nature or their yield and nutritional quality in agriculture. Major biogeochemical fluxes of all elements occur through plant roots, and the roots of agricultural crops have a significant role to play in soil sustainability, carbon sequestration, reducing emissions of greenhouse gasses, and in preventing the eutrophication of water bodies associated with the application of mineral fertilizers. SCOPE: This article provides the context for a Special Issue of Annals of Botany on 'Matching Roots to Their Environment'. It first examines how land plants and their roots evolved, describes how the ecology of roots and their rhizospheres contributes to the acquisition of soil resources, and discusses the influence of plant roots on biogeochemical cycles. It then describes the role of roots in overcoming the constraints to crop production imposed by hostile or infertile soils, illustrates root phenotypes that improve the acquisition of mineral elements and water, and discusses high-throughput methods to screen for these traits in the laboratory, glasshouse and field. Finally, it considers whether knowledge of adaptations improving the acquisition of resources in natural environments can be used to develop root systems for sustainable agriculture in the future.

Establishing the Minimum Intensity of Transcranial Magnetic Stimulation Superconditioning Pulses to Effect Inhibition and Facilitation of Motor Evoked Potentials.

PURPOSE: Previously, we showed that a three-pulse train of weak transcranial magnetic stimulation (TMS) pulses-a superconditioning (SC) train-when followed by a stronger TMS pulse could enhance the inhibition or facilitation of the resultant motor evoked potential (MEP) compared with that seen with traditional dual-pulse inputs. The purpose of the present study was to establish the relative minimum intensity of SC pulses needed to influence MEP output and whether this differed for upper- versus lower-limb muscles. METHODS: We examined 33 older adult subjects, targeting abductor pollicis brevis and tibialis anterior muscles. Older subjects were included in the anticipation of using findings from this study to guide further studies in persons with amyotrophic lateral sclerosis. Three-pulse trains of SC inputs of different intensities were delivered either 1 millisecond before (for inhibition) or 10 millisecond before (for facilitation) a stronger TMS test pulse. Motor evoked potential magnitudes for SC +test sets were normalized to test input responses and were compared within and between subjects. RESULTS AND CONCLUSIONS: For inhibition, the minimum intensity of SC pulses needed to influence the follow-on MEP was found to be 60% of the target muscle's resting three-pulse MEP threshold for most abductor pollicis brevis and tibialis anterior muscles (2-millisecond interpulse intervals). For facilitation, somewhat higher intensities (70%) were typically needed to cause facilitation. Both values of SC pulses for inhibition/facilitation are considerably lower than the intensity of the conditioning pulse-often reported as 80% of the single-pulse threshold-typically used in dual-pulse TMS paradigms. This approach may allow testing of upper motor neuron function using weaker stimulus pulse intensities than are typically employed, improving testing compliance in persons whose thresholds are elevated because of injury or disease.