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At least 199 records · Page 11Linked to original sources

PubMed2002

Cross-modal interactions between audition, touch, and vision in endogenous spatial attention: ERP evidence on preparatory states and sensory modulations.

Recent behavioral and event-related brain potential (ERP) studies have revealed cross-modal interactions in endogenous spatial attention between vision and audition, plus vision and touch. The present ERP study investigated whether these interactions reflect supramodal attentional control mechanisms, and whether similar cross-modal interactions also exist between audition and touch. Participants directed attention to the side indicated by a cue to detect infrequent auditory or tactile targets at the cued side. The relevant modality (audition or touch) was blocked. Attentional control processes were reflected in systematic ERP modulations elicited during cued shifts of attention. An anterior negativity contralateral to the cued side was followed by a contralateral positivity at posterior sites. These effects were similar whether the cue signaled which side was relevant for audition or for touch. They also resembled previously observed ERP modulations for shifts of visual attention, thus implicating supramodal mechanisms in the control of spatial attention. Following each cue, single auditory, tactile, or visual stimuli were presented at the cued or uncued side. Although stimuli in task-irrelevant modalities could be completely ignored, visual and auditory ERPs were nevertheless affected by spatial attention when touch was relevant, revealing cross-modal interactions. When audition was relevant, visual ERPs, but not tactile ERPs, were affected by spatial attention, indicating that touch can be decoupled from cross-modal attention when task-irrelevant.

Adult↗

PubMed2026

Microbial partnerships and molecular mechanisms in plant stress physiology for climate-resilient and sustainable farming.

Plant-microbial partnerships and their underlying molecular mechanisms are indispensable, natural drivers of improved nutrient acquisition and stress tolerance in the face of climate-driven environmental challenges. Modern multi-omics tools, when coupled with artificial intelligence and synthetic biology, enable the precise design of targeted bioinoculants and synthetic microbial consortia. Translating these advanced microbiome-based strategies into scalable, field-level agricultural applications provides a sustainable path toward securing global food production while maintaining soil health. Global climate change imposes multifaceted abiotic and biotic stresses on crops, disrupting physiological and molecular processes and threatening agricultural productivity. Plant-associated microbes represent an underexplored yet powerful ally in enhancing crop resilience. This review presents current knowledge of plant-microbe interactions and the molecular mechanisms governing plant stress physiology, with an emphasis on climate-resilient and sustainable farming. Hence, ever-changing environmental cues pose a significant burden on agricultural productivity, and plant-associated microbial communities modulate a cascade of physiological and molecular responses, including production of phytohormones, signaling, regulation of reactive oxygen species homeostasis, and activation of plant immune responses to help plants withstand stress and enhance productivity. Moreover, root exudates, phytohormones, and quorum sensing mediate the central communication networks, facilitating plant-microbe cross talk. Additionally, the advances in OMICs approaches aid in disentangling the molecular underpinnings of these interactions by providing mechanistic insights and potential candidate gene targets for crop improvement and stress resilience. In the post-genomic era, integrating artificial intelligence and big data analysis to optimize microbiome-based strategies for sustainable agriculture is a new frontier for disentangling plant-microbe symbiosis to improve soil health, enhance crop yields, and improve stress tolerance. Thus, by integrating the ecological, physiological, and molecular perspectives, this review highlights the transformative potential of harnessing plant-microbe symbiosis for climate-resilient and sustainable agriculture.

Stress, Physiological↗

PubMed2000

Modulation of human visual cortex by crossmodal spatial attention.

A sudden touch on one hand can improve vision near that hand, revealing crossmodal links in spatial attention. It is often assumed that such links involve only multimodal neural structures, but unimodal brain areas may also be affected. We tested the effect of simultaneous visuo-tactile stimulation on the activity of the human visual cortex. Tactile stimulation enhanced activity in the visual cortex, but only when it was on the same side as a visual target. Analysis of effective connectivity between brain areas suggests that touch influences unimodal visual cortex via back-projections from multimodal parietal areas. This provides a neural explanation for crossmodal links in spatial attention.

Adult↗

PubMed2005

Multisensory stimulation with or without saccades: fMRI evidence for crossmodal effects on sensory-specific cortices that reflect multisensory location-congruence rather than task-relevance.

During covert attention to peripheral visual targets, presenting a concurrent tactile stimulus at the same location as a visual target can boost neural responses to it, even in sensory-specific occipital areas. Here, we examined any such crossmodal spatial-congruence effects in the context of overt spatial orienting, when saccadic eye-movements were directed to each peripheral target or central fixation maintained. In addition, we tested whether crossmodal spatial-congruence effects depend on the task-relevance of visual or tactile stimuli. On each trial, subjects received spatially congruent (same location) or incongruent (opposite hemifields) visuo-tactile stimulation. In different blocks, they made saccades either to the location of each visual stimulus, or to the location of each tactile stimulus; or else passively received the multisensory stimulation. Activity in visual extrastriate areas and in somatosensory parietal operculum was modulated by spatial congruence of the multisensory stimulation, with stronger activations when concurrent visual and tactile stimuli were both delivered at the same contralateral location. Critically, lateral occipital cortex and parietal operculum showed such crossmodal spatial effects irrespective of which modality was task relevant; and also of whether the stimuli were used to guide eye-movements or were just passively received. These results reveal crossmodal spatial-congruence effects upon visual and somatosensory sensory-specific areas that are relatively 'automatic', determined by the spatial relation of multisensory input rather than by its task-relevance.

Adolescent↗

PubMed2006

Mechanisms of Disease: the first kiss-a crucial role for kisspeptin-1 and its receptor, G-protein-coupled receptor 54, in puberty and reproduction.

Although the hypothalamic secretion of gonadotropin-releasing hormone (GnRH) is the defining hormonal event of puberty, the physiologic mechanisms that drive secretion of GnRH at the time of sexual maturation have been difficult to identify. After puberty is initiated, the factors that modulate the frequency and amplitude of GnRH secretion in rapidly changing sex-steroid environments (i.e. the female menstrual cycle) also remain unknown. The discovery that, in both humans and mouse models, loss-of-function mutations in the gene that encodes G-protein-coupled receptor 54 result in phenotypes of hypogonadotropic hypogonadism with an absence of pubertal development has unearthed a novel pathway regulating GnRH secretion. Ligands for G-protein-coupled receptor 54 (KiSS-1R), including metastin (derived from the parent compound, kisspeptin-1) and metastin's C-terminal peptide fragments, have been shown to be powerful stimulants for GnRH release in vivo via their stimulation of G-protein-coupled receptor 54. This article reviews the discovery of the GPR54 gene, places it into the appropriate biological context, and explores the data from in vitro and in vivo studies that point to this ligand-receptor system as a major driver of GnRH secretion.

Animals↗

PubMed2026

Characteristics and assembly mechanisms of tobacco-associated bacteria in typical tobacco-planting regions across China.

INTRODUCTION: Plant-associated microbiota critically modulates host growth and environmental adaptation, yet assembly mechanisms, niche differentiation, and ecological strategies of bacterial communities inhabiting tobacco microhabitats remain poorly elucidated across geographical gradients. METHODS: Here, we systematically characterized bacterial microbiome assembly across five tobacco-associated niches (bulk soil, rhizosphere soil, root, stem, and leaf) from seven typical tobacco-planting regions using 16S rRNA amplicon sequencing, genome annotation, and niche breadth analysis. The independent and interactive effects of geographical location and host compartment on community structure, and further compared genomic traits, functional profiles, and life-history strategies between specialist and generalist bacterial populations were quantified. RESULTS: The results revealed a deterministic soil-plant continuum stratification of bacterial communities and diversity, with progressively simplified communities and decreasing alpha diversity from bulk soil to above-ground tissues, accompanied by progressive dominance of Proteobacteria. Geographical factors predominantly structured soil microbial communities via divergent edaphic properties, while host filtering acted as a universal dominant driver shaping endophytic microbiome assembly. Niche differentiation analysis demonstrated that niche-specialized bacterial ASVs overwhelmingly dominated all microhabitats and geographical sites, whereas generalist taxa only constituted auxiliary populations. Although specialist and generalist microbes exhibited highly conserved core genomic architectures and overall functional repertoires, they displayed distinct niche-specific functional divergence in metabolic pathways, stress resistance, and secondary metabolism across host compartments. Life-history strategy analysis further revealed that Y-strategist represented the core adaptive bacterial population, especially enriched in above-ground tobacco tissues. DISCUSSION: Our study establishes a hierarchical dual-filtering assembly model for tobacco microbiota, clarifies the ecological differentiation and functional adaptation of specialist and generalist bacteria, and provides fundamental insights into the assembly rules and adaptive mechanisms of crop-associated microbiomes for future microbial resource utilization and agricultural microbiome regulation.

biogeography↗

PubMed2001

Seen gaze-direction modulates fusiform activity and its coupling with other brain areas during face processing.

Gaze-contact is often a preliminary to social interaction and so constitutes a signal for the allocation of processing resources to the gazing face. We investigated how gaze direction influences face processing in an fMRI study, where seen gaze and head direction could independently be direct or deviated. Direct relative to averted gaze elicited stronger activation for faces in ventral occipitotemporal cortices around the fusiform gyrus, regardless of head orientation. Moreover, direct gaze led to greater correlation between activity in the fusiform and the amygdala, a region associated with emotional responses and stimulus saliency. By contrast, faces with averted gaze (again, regardless of head orientation) yielded increased correlation between activity in the fusiform and the intraparietal sulcus, a region associated with shifting attention to the periphery.

Adult↗

PubMed1995

Antiviral activity of a phosphorothioate oligonucleotide complementary to human cytomegalovirus RNA when used in combination with antiviral nucleoside analogs.

ISIS 2922 is a phosphorothioate oligonucleotide with potent antiviral activity against human cytomegalovirus (HCMV) in cell culture assays. The ability of ISIS 2922 to inhibit replication of HCMV when used in combination with other antiviral agents approved for treatment of HCMV disease was investigated using a 96-well immunoassay. The antiviral activity of ISIS 2922 against HCMV was additive with that of ganciclovir (9-(1,3-dihydroxy-2-propoxymethylguanine); DHPG) or foscarnet (phosphonoformate). Compounds used clinically for the treatment of human immunodeficiency virus infection and likely to be co-administered with ISIS 2922 in the clinic were also evaluated for their ability to modulate the antiviral activity of ISIS 2922. 3'-Azido-3'-deoxythymidine (AZT) exhibited no antiviral activity against HCMV in the 96-well immunoassay, and did not significantly alter the antiviral activity of ISIS 2922. 2'-3'-Dideoxycytidine (ddC) was able to inhibit replication of HCMV at high doses, and this activity was additive with that of ISIS 2922. ISIS 2922 inhibited HIV replication in acute infection assays at relatively high concentrations as previously reported for non-complementary phosphorothioate oligonucleotides. When ISIS 2922 was used in combination with AZT in this assay, interactions were additive at most concentrations, although significant and reproducible synergy was observed at some concentration combinations.

Antiviral Agents↗

PubMed2026

In vivo epigenome editing reduces circulating lipids and attenuates atherosclerosis in mice.

Atherosclerotic cardiovascular disease remains the leading cause of global mortality, with hypercholesterolemia serving as a critical driver of atherogenesis. Although current lipid-lowering therapies substantially improve circulating lipid profiles, strategies that provide more durable, safe, and efficient control of lipid metabolism are still needed. Epigenome editing offers a promising approach for long-lasting repression of disease-modifying genes without altering the underlying DNA sequence. Here, we develop CRISPRoff platforms delivered by adeno-associated virus or lipid nanoparticle to epigenetically silence hepatic Hmgcr or Pcsk9 in vivo. In both C57BL/6J wild-type and ApoE-/- mice, CRISPRoff mediates robust and durable repression of these targets, leading to marked reductions in circulating total cholesterol, low-density lipoprotein cholesterol, and triglycerides. In the ApoE-/- context, epigenetic silencing of Pcsk9 confers pronounced vascular protection, including decreased lipid accumulation in the liver and aortic root, reduced necrotic core formation, diminished macrophage infiltration, and enhanced plaque stability. Together, these results provide proof of principle that CRISPRoff-based epigenome editing enables stable repression of clinically relevant targets and ameliorates key features of atherosclerotic disease. This work lays the foundation for broader therapeutic applications of epigenetic modulation in cardiovascular disorders.

Animals↗

PubMed2005

Ligand-activated Flpe for temporally regulated gene modifications.

The selectivity by which site-specific recombinase-mediated genetic changes can be targeted to specific cells in the mouse has been limited by the fact that many genes used as recombinase "drivers" are expressed either in cell populations that change over time or constitutively in a given cell population for an extended time period, for example, in a germinal zone that gives rise successively to different lineages. These scenarios limit the selective dimension of conditional gene modification experiments as they preclude studying the later-generated lineages either because of earlier phenotypes (in the case of conditional mutagenesis experiments) or because the early and permanent activation of a reporter in a germinal zone results in all descendant lineages being marked (in the case of fate-mapping experiments). To circumvent this limitation, inducible forms of Cre recombinase have been developed, enabling the induction of genetic changes in late embryonic or adult cells accessible only through late aspects of a dynamic driver gene expression profile. To increase the number of tools available for engineering genetic changes in selective cell populations, we have generated a ligand-regulated form of Flpe using the recombinase-steroid receptor fusion approach. In two prototypical scenarios, we show that the fused gene product, FlpeER(T2), is competent to mediate DNA recombination in vivo and responds specifically to the inducer tamoxifen in a dose-dependent manner without detectable background activity.

Animals↗

PubMed2002

Directing attention to locations and to sensory modalities: multiple levels of selective processing revealed with PET.

We used positron emission tomography (PET) to investigate the neural correlates of selective attention in humans. We examined the effects of attending to one side of space versus another (spatial selection) and to one sensory modality versus another (intermodal selection) during bilateral, bimodal stimulation of vision and touch. Attention toward one side resulted in greater activity in several contralateral areas. In somatosensory cortex, these spatial attentional modulations were found only when touch was relevant. In the intraparietal sulcus, spatial attentional effects were multimodal, independent of the modality attended. In occipital areas, spatial modulations were also found during both visual and tactile attention, indicating that tactile attention can affect activity in visual cortex; but occipital areas also showed more activity overall during visual attention. This suggests that while spatial attention can exert multimodal influences on visual areas, these still maintain their specificity for the visual modality. Additionally, irrespective of the attended side, attending to vision activated posterior parietal and superior premotor cortices, while attending to touch activated the parietal operculi. We conclude that attentional selection operates at multiple levels, with attention to locations and attention to modalities showing distinct effects. These jointly contribute to boost processing of stimuli at the attended location in the relevant modality.

Adult↗

PubMed2026

Retrotransposable element derepression distinguishes DNMT3A-mutant from TET2-mutant clonal haematopoiesis.

Clonal haematopoiesis (CH) is driven by somatic mutations in haematopoietic stem cells that generate clonal populations detectable in peripheral blood and is present in 10-20% of individuals over the age of 65. Mutations in DNMT3A and TET2 are the most common drivers and have been linked to inflammatory phenotypes and increased risk of haematologic and cardiovascular disease. However, the cell-intrinsic mechanisms connecting these mutations to inflammatory signalling remain incompletely understood. Because retrotransposable elements (RTEs) are epigenetically regulated and can activate innate immune pathways when derepressed, we hypothesised that RTE reactivation may represent a mutation-specific mechanism linking clonal haematopoiesis driver mutations to inflammatory pathways. We analysed RTE expression and clonal burden in peripheral blood mononuclear cell (PBMC) samples from 56 individuals with CH and 12 non-CH controls using integrated genomic and transcriptomic approaches, with complementary validation by TARGET-seq across haematopoietic lineages. High variant allele frequency (VAF; > 10%) DNMT3A-mutant clones exhibited widespread derepression of RTEs, particularly LINE and LTR families, whereas TET2-mutant clones showed a trend towards reduced RTE expression relative to controls. Transcriptomic analyses revealed that DNMT3A high-variant allele frequency clones with elevated RTE expression were enriched for inflammatory signalling pathways, including TNF-α/NF-κB signalling, interferon responses, and senescence-associated signatures. In contrast, TET2-mutant clones lacked these RTE-associated inflammatory signatures and instead showed enrichment of oxidative phosphorylation, reactive oxygen species signalling, and a mechanistic target of rapamycin complex 1 pathway. These findings were reproduced in an independent cohort. Collectively, our results highlight mutation-specific inflammatory mechanisms in clonal haematopoiesis and provide a foundation for future functional and preclinical studies to determine whether modulation of RTE activity can influence the inflammatory phenotype of DNMT3A-mutant CH and represent a potential therapeutic strategy.

DNMT3A↗

PubMed2026

Boreal and subarctic freshwaters harbour a diversity of jumbophages.

Bacteriophages (phages) are major drivers of microbial evolution and ecology, yet their diversity and functional roles remain poorly characterized in many natural environments, such as in freshwater systems. In boreal and subarctic freshwater habitats, where bacteria are typically slow-growing and nutrient-limited, phages are predicted to have a critical role in host regulation and horizontal gene exchange. However, only a few isolates have been obtained from such environments, leaving the genetic and functional diversity of these phages largely unexplored. Here, we present a collection of 40 bacteriophages isolated from boreal lakes and rivers using a set of diverse freshwater bacterial hosts. Despite using conventional isolation methods, eight of the isolates possess genomes larger than 200 kilobases and are classified as jumbophages. All jumbophages exhibited myovirus morphology and comparatively slow infection dynamics. These jumbophages include the first known representatives infecting members of Janthinobacterium and Herbaspirillum. Comparative genomic and phylogenetic analyses show that nearly all genomes are distinct from previously described phages, indicating substantial novelty. Diverse auxiliary metabolic and anti-defence systems were identified, including putative NAD+ salvage and acyl carrier protein modules, along with predicted Anti-Thoeris and Anti-CBASS elements. The Pseudomonas-infecting jumbophage Ahti encoded homologues of all 21 core genes that define the nucleus-forming family Chimalliviridae. Additionally, Ahti displayed compartmentalization of DNA during infection, establishing it as the first freshwater nucleus-forming phage. These findings expand our understanding of the ecological, genomic, and functional diversity of phages in boreal environments and highlight the role of freshwater ecosystems as significant reservoirs of novel viral lineages.

anti-defence systems↗

PubMed2026

Evolution after whole-genome duplication (WGD) drives phenotypic and transcriptomic divergence more than WGD in an autopolyploid herb.

Whole-genome duplication (WGD) is a major driver of plant speciation and often hypothesized to promote rapid adaptation to new or changing environmental conditions. However, the extent to which WGD per se fosters phenotypic and transcriptional novelties, and the relative contribution of WGD-induced changes vs post-WGD evolution to trait differentiation between cytotypes remains poorly understood. Here, we investigated the phenotypic and transcriptomic consequences of WGD and subsequent evolution in the Biscutella laevigata diploid-autotetraploid complex by comparing replicated diploid, synthetic autotetraploids, and natural autotetraploids (originated some 24,000 to 7,000 generations ago) under moderate daily temperature fluctuations (stable) vs. daily heat stress (changing) conditions. WGD led to reduced specific leaf area and slower rosette growth but had no significant effect on biomass. Post-WGD evolution acted in contrasting directions on WGD-induced changes, either reverting traits to diploid-like values or maintaining them in natural autotetraploids. Overall, WGD induced a decrease in fitness that was mitigated by post-WGD evolution, resulting in natural autotetraploids with similar or higher fitness under changing conditions than diploids. While the genetic background modulates the effects of WGD, cytotype-level transcriptomic analyses revealed limited immediate effects of WGD under stable conditions, although heat stress induced different responses across cytotypes. Altogether, our results highlight a complex interplay between immediate WGD-induced and subsequent evolution at the phenotypic and transcriptomic levels, supporting a predominant role of post-WGD evolution in the differentiation of current cytotypes and the adaptive evolution of autotetraploids of B. laevigata.

Genome, Plant↗

PubMed2004

ERP evidence for cross-modal audiovisual effects of endogenous spatial attention within hemifields.

Previous ERP studies have uncovered cross-modal interactions in endogenous spatial attention. Directing attention to one side to judge stimuli from one particular modality can modulate early modality-specific ERP components not only for that modality, but also for other currently irrelevant modalities. However, past studies could not determine whether the spatial focus of attention in the task-irrelevant secondary modality was similar to the primary modality, or was instead diffuse across one hemifield. Here, auditory or visual stimuli could appear at any one of four locations (two on each side). In different blocks, subjects judged stimuli at only one of these four locations, for an auditory (Experiment 1) or visual (Experiment 2) task. Early attentional modulations of visual and auditory ERPs were found for stimuli at the currently relevant location, compared with those at the irrelevant location within the same hemifield, thus demonstrating within-hemifield tuning of spatial attention. Crucially, this was found not only for the currently relevant modality, but also for the currently irrelevant modality. Moreover, these within-hemifield attention effects were statistically equivalent regardless of the task relevance of the modality, for both the auditory and visual ERP data. These results demonstrate that within-hemifield spatial attention for one task-relevant modality can transfer cross-modally to a task-irrelevant modality, consistent with spatial selection at a multimodal level of representation.

Acoustic Stimulation↗

PubMed1996

Inspiratory drive and phase duration during carotid chemoreceptor stimulation in the cat: medullary neurone correlations.

1. This study addressed the hypothesis that there is a parallel processing of input from carotid chemoreceptors to brainstem neurones involved in inspiratory phase timing and control of inspiratory motor output amplitude. Data were from fifteen anaesthetized, bilaterally vagotomized, paralysed, artificially ventilated cats. Carotid chemoreceptors were stimulated by close arterial injection of 200 microliters of CO2-saturated saline solution. 2. Planar arrays of tungsten microelectrodes were used to monitor simultaneously up to twenty-two neurones in the nucleus tractus solitarii (NTS) and ventral respiratory group (VRG). Spike trains were analysed with two statistical tests of respiratory modulation, cycle-triggered histograms, peristimulus-time histograms, cumulative sum histograms and cross-correlograms. 3. In NTS, 16 of 26 neurones with respiratory and 12 of 27 without respiratory modulation changed firing rate during carotid chemoreceptor stimulation. In the VRG 72 of 112 respiratory and 14 of 48 non-respiratory neurones changed firing rate during stimulation. 4. The spike trains of 85 of 1276 pairs (6.7%) of cells exhibited short time scale correlations indicative of paucisynaptic interactions. Ten pairs of neurones were each composed of a rostral VRG phasic inspiratory neurone that responded to carotid chemoreceptor stimulation with a decline in firing rate and a caudal VRG phasic inspiratory neurone that increased its firing rate. Cross-correlograms from two of the pairs had features consistent with excitation of the caudal neurones by the rostral cells. A decrease in the duration of activity of the rostral VRG neurones was paralleled by the decrease in inspiratory time of phrenic nerve activity. Caudal VRG inspiratory neurones increased their activity as phrenic amplitude increased. Spike-triggered averages of all four neurones indicated post-spike facilitation of phrenic motoneurones. 5. The results support the hypothesis that unilateral stimulation of carotid chemoreceptors results in parallel actions. (a) Inhibition of rostral VRG I-Driver neurones decreases inspiratory duration. (b) Concurrent excitation of premotor VRG and dorsal respiratory group inspiratory neurones increases inspiratory drive to phrenic motoneurones. Other data suggest that responsive ipsilateral neurones act to regulate contralateral neurones.

Animals↗

PubMed2003

Message and protein-level elevation of tumor necrosis factor alpha (TNF alpha) and TNF alpha-modulating cytokines in spinal cords of the G93A-SOD1 mouse model for amyotrophic lateral sclerosis.

Recent data indicate that certain pro-inflammatory cytokines are transcriptionally upregulated in the spinal cords of G93A-SOD1 mice, a model of amyotrophic lateral sclerosis (ALS). We previously showed that the receptor for tumor necrosis factor alpha (TNF-R1) was notably elevated at late presymptomatic as well as symptomatic phases of disease (J. Neurochem. 82 (2002) 365). We now extend these findings by showing that message for TNFalpha, as well as mRNA for interferon gamma (IFNgamma) and transforming growth factor beta1/2 (TGFbeta1, TGFbeta2), is simultaneously increased. Furthermore, TNFalpha protein is significantly increased in G93A-SOD1 mouse spinal cords, as are protein levels for interleukin-6 (IL6), IFNgamma, and the chemokines RANTES (CCL5) and KC. The interaction of TNFalpha, IL6, and IFNgamma proteins was modeled in vitro using Walker EOC-20 murine microglia with nitrite (NO(2)(-)) efflux as a quantitative index of cell response. TNFalpha alone caused robust NO(2)(-) flux, while IL6 had a lesser effect and neither IFNgamma nor IL1beta was active when applied singly. The TNFalpha stimulus was potently magnified in the presence of IL6 or IFNgamma. When applied in combination at very low concentrations, IFNgamma co-synergized with IL6 to produce a multiplicative increase in NO(2)(-) after stimulation with TNFalpha. Taken together, these data suggest that modest increases in multiple synergistic cytokines could produce a disproportionately severe activation of microglia within the degenerating spinal cord. Our data support a model wherein TNFalpha acts as a principal driver for neuroinflammation, while several co-stimulating cytokines and chemokines act to potentiate the TNFalpha effects.

Amino Acid Substitution↗

PubMed2006

Biomass responses to elevated CO2, soil heterogeneity and diversity: an experimental assessment with grassland assemblages.

While it is well-established that the spatial distribution of soil nutrients (soil heterogeneity) influences the competitive ability and survival of individual plants, as well as the productivity of plant communities, there is a paucity of data on how soil heterogeneity and global change drivers interact to affect plant performance and ecosystem functioning. To evaluate the effects of elevated CO(2), soil heterogeneity and diversity (species richness and composition) on productivity, patterns of biomass allocation and root foraging precision, we conducted an experiment with grassland assemblages formed by monocultures, two- and three-species mixtures of Lolium perenne, Plantago lanceolata and Holcus lanatus. The experiment lasted for 90 days, and was conducted on microcosms built out of PVC pipe (length 38 cm, internal diameter 10 cm). When nutrients were heterogeneously supplied (in discrete patches), assemblages exhibited precise root foraging patterns, and had higher total, above- and belowground biomass. Greater aboveground biomass was observed under elevated CO(2). Species composition affected the below:aboveground biomass ratio and interacted with nutrient heterogeneity to determine belowground and total biomass. Species richness had no significant effects, and did not interact with either CO(2) or nutrient heterogeneity. Under elevated CO(2) conditions, the two- and three-species mixtures showed a clear trend towards underyielding. Our results show that differences among composition levels were dependent on soil heterogeneity, highlighting its potential role in modulating diversity-productivity relationships.

Analysis of Variance↗