Mechanism of the Pulvinus-Driven Leaf Movement: An Overview.

Leaf movement is a manifestation of plant response to the changing internal and external environment, aiming to optimize plant growth and development. Leaf movement is usually driven by a specialized motor organ, the pulvinus, and this movement is associated with different changes in volume and expansion on the two sides of the pulvinus. Blue light, auxin, GA, H+-ATPase, K+, Cl-, Ca2+, actin, and aquaporin collectively influence the changes in water flux in the tissue of the extensor and flexor of the pulvinus to establish a turgor pressure difference, thereby controlling leaf movement. However, how these factors regulate the multicellular motility of the pulvinus tissues in a species remains obscure. In addition, model plants such as Medicago truncatula, Mimosa pudica, and Samanea saman have been used to study pulvinus-driven leaf movement, showing a similarity in their pulvinus movement mechanisms. In this review, we summarize past research findings from the three model plants, and using Medicago truncatula as an example, suggest that genes regulating pulvinus movement are also involved in regulating plant growth and development. We also propose a model in which the variation of ion flux and water flux are critical steps to pulvinus movement and highlight questions for future research.

Structure, chemical modification, and functional applications of mucilage from Mimosa pudica seeds - A review.

Mimosa pudica (MP) is an ornamental plant due to seismonastic movements that close leaves and fall petioles in response to touch, wind, light, heat, cold, and vibration. The seeds of MP secrete smart, biocompatible, and non-toxic mucilage that has captivated researchers due to its widespread use in various fields such as pharmaceuticals and biotechnology. The mucilage is responsive to pH, salt solutions, and solvents and acts as a binder in tablet formulations for targeted drug delivery. The mucilage is chemically modifiable via acetylation, succinylation, and graft polymerization. Chemically modified MP mucilage appeared supersorbent for heavy metal ion uptake. Nanoparticles synthesized using mucilage as a reducing and capping agent displayed significant antimicrobial and wound-healing potential. Crosslinking of mucilage using citric acid as a crosslinking agent offers a sustained release of drugs. The present review is aimed to discuss extraction optimization, structure, modification, and the stimuli-responsive nature of mucilage. The review article will cover the potential of mucilage as emulsifying, suspending, bio-adhesive, gelling, and thickening agent. The role of mucilage as a capping and reducing agent for nanoparticles will also be discussed.

Haplotype-resolved genome of Mimosa bimucronata revealed insights into leaf movement and nitrogen fixation.

BACKGROUND: Mimosa bimucronata originates from tropical America and exhibits distinctive leaf movement characterized by a relative slow speed. Additionally, this species possesses the ability to fix nitrogen. Despite these intriguing traits, comprehensive studies have been hindered by the lack of genomic resources for M. bimucronata. RESULTS: To unravel the intricacies of leaf movement and nitrogen fixation, we successfully assembled a high-quality, haplotype-resolved, reference genome at the chromosome level, spanning 648 Mb and anchored in 13 pseudochromosomes. A total of 32,146 protein-coding genes were annotated. In particular, haplotype A was annotated with 31,035 protein-coding genes, and haplotype B with 31,440 protein-coding genes. Structural variations (SVs) and allele specific expression (ASE) analyses uncovered the potential role of structural variants in leaf movement and nitrogen fixation in M. bimucronata. Two whole-genome duplication (WGD) events were detected, that occurred ~ 2.9 and ~ 73.5 million years ago. Transcriptome and co-expression network analyses revealed the involvement of aquaporins (AQPs) and Ca2+-related ion channel genes in leaf movement. Moreover, we also identified nodulation-related genes and analyzed the structure and evolution of the key gene NIN in the process of symbiotic nitrogen fixation (SNF). CONCLUSION: The detailed comparative genomic and transcriptomic analyses provided insights into the mechanisms governing leaf movement and nitrogen fixation in M. bimucronata. This research yielded genomic resources and provided an important reference for functional genomic studies of M. bimucronata and other legume species.

Vasorelaxant Activity of (2S)-Sakuranetin and Other Flavonoids Isolated from the Green Propolis of the Caatinga Mimosa tenuiflora.

Some in vitro and in vivo evidence is consistent with the cardiovascular beneficial activity of propolis. As the single actors responsible for this effect have never been identified, an in-depth investigation of flavonoids isolated from the green propolis of the Caatinga Mimosa tenuiflora was performed and their mechanism of action was described. A comprehensive electrophysiology, functional, and molecular docking approach was applied. Most flavanones and flavones were effective CaV1.2 channel blockers with a potency order of (2S)-sakuranetin > eriodictyol-7,3'-methyl ether > quercetin 3-methyl ether > 5,4'-dihydroxy-6,7-dimethoxyflavanone > santin > axillarin > penduletin > kumatakenin, ermanin and viscosine being weak or modest stimulators. Except for eriodictyol 5-O-methyl ether, all the flavonoids were also effective spasmolytic agents of vascular rings, kumatakenin and viscosine also showing an endothelium-dependent activity. (2S)-Sakuranetin also stimulated KCa1.1 channels both in single myocytes and vascular rings. In silico analysis provided interesting insights into the mode of action of (2S)-sakuranetin within both CaV1.2 and KCa1.1 channels. The green propolis of the Caatinga Mimosa tenuiflora is a valuable source of multi-target vasoactive flavonoids: this evidence reinforces its nutraceutical value in the cardiovascular disease prevention arena.

Development and evaluation of a pH-responsive Mimosa pudica seed mucilage/ß- cyclodextrin-co-poly(methacrylate) hydrogel for controlled drug delivery: In vitro and in vivo assessment.

In this comprehensive investigation, a novel pH-responsive hydrogel system comprising mimosa seed mucilage (MSM), ß-cyclodextrin (ß-CD), and methacrylic acid (MAA) was developed via free radical polymerization technique to promote controlled drug delivery. The hydrogel synthesis involved strategic variations in polymer, monomer, and crosslinker content in fine-tuning its drug-release properties. The resultant hydrogel exhibited remarkable pH sensitivity, selectively liberating the model drug (Capecitabine = CAP) under basic conditions while significantly reducing release in an acidic environment. Morphological, thermal, and structural analyses proved that CAP has a porous texture, high stability, and an amorphous nature. In vitro drug release experiments showcased a sustained and controlled release profile. Optimum release (85.33 %) results were recorded over 24 h at pH 7.4 in the case of MMB9. Pharmacokinetic evaluation in healthy male rabbits confirmed bioavailability enhancement and sustained release capabilities. Furthermore, rigorous toxicity evaluations and histopathological analyses ensured the safety and biocompatibility of the hydrogel. This pH-triggered drug delivery system can be a promising carrier system for drugs involving frequent administrations.

3,3'-O-dimethylquercetin: A bi-functional vasodilator isolated from green propolis of the Caatinga Mimosa tenuiflora.

In the search for novel, bi-functional compounds acting as CaV1.2 channel blockers and K+ channel stimulators, which represent an effective therapy for hypertension, 3,3'-O-dimethylquercetin was isolated for the first time from Brazilian Caatinga green propolis. Its effects were investigated through electrophysiological, functional, and computational approaches. In rat tail artery myocytes, 3,3'-O-dimethylquercetin blocked Ba2+ currents through CaV1.2 channels (IBa1.2) in a concentration-dependent manner, with the inhibition being reversed upon washout. The compound also shifted the voltage dependence of the steady-state inactivation curve to more negative potentials without affecting the slope of the inactivation and activation curves. Furthermore, the flavonoid stimulated KCa1.1 channel currents (IKCa1.1). In silico simulations provided additional evidence for the binding of 3,3'-O-dimethylquercetin to KCa1.1 and CaV1.2 channels and elucidated its mechanism of action. In depolarized rat tail artery rings, the flavonoid induced a concentration-dependent relaxation. Moreover, in rat aorta rings its antispasmodic effect was inversely related to the transmembrane K+ gradient. In conclusion, 3,3'-O-dimethylquercetin demonstrates effective in vitro vasodilatory properties, encouraging the exploration of its scaffold to develop novel derivatives for potential use in the treatment of hypertension.

Chemical profile and evaluation of the pharmacological activity of the dry extract and fraction of ethyl acetate obtained from the leaves of Mimosa caesalpiniifolia.

ETHNOPHARMACOLOGICAL RELEVANCE: Mimosa caesalpiniifolia (Sansão-do-Campo) is a native species of the caatinga in northeastern Brazil that has been studied for its potential anti-inflammatory and antidepressant activity. It is popularly consumed as a medicinal plant and its pharmacological benefits are evidenced in the literature. AIM OF THE STUDY: The present work was carried out to promote the chemical profile and evaluate the pharmacological activity of the dry extract and the ethyl acetate fraction obtained from the dry leaves of Mimosa caesalpiniifolia. MATERIALS AND METHODS: The leaves were collected in the municipality of Alfenas-MG and subjected to drying, followed by division in a knife mill. The preparation of the dry extract was carried out by the extraction method using simple percolation and the fraction was obtained by liquid-liquid partition. Part of the extractive solution was concentrated in a rotary evaporator followed by a drying process using the spray technique with the addition of colloidal silicon dioxide. The dry extract (33.33%) showed a higher yield in mass when compared to the yield of the ethyl acetate fraction (19.67%). The in vivo pharmacological evaluation was conducted with a total of 82 male Wistar rats that underwent cecal ligation and perforation surgery to induce the inflammatory process. One week after surgery, these animals were treated for 7 days with the dry extract and the ethyl acetate fraction and submitted to behavioral tests (open field and forced swimming). RESULTS: The chemical results were obtained through analysis by HPLC-PDA coupled to a mass spectrometer, enabling the verification of the presence of phenolic acids, flavonoids, aglycones, and glycosides, in addition to tannins. This corroborates with data present in the literature for the genus Mimosa sp. Some compounds had their structure determined, where they were identified as catechin (m/z 288.97), cassiaocidentalin A (m/z 560.75), and procyanidin B2 [(epi)catechin-(epi)catechin; m/z 576.83)]. It was found that the animals that were submitted to the treatment did not present statistically significant results, demonstrating that the pharmacological action evaluated in the test was not highlighted in this type of experiment. The groups that underwent treatment had an aggravated locomotor activity. CONCLUSIONS: The results found with the chemical study contributed to the knowledge of the plant species studied. On the other hand, further studies are needed to provide a better understanding of the pharmacological evaluation of Mimosa caesalpiniifolia.

Free amino acid profile in Mimosa scabrella honeydew honey from Brazil and chemometric analysis for geographical discrimination.

In this study, twenty free amino acids (FAA) were investigated in samples of bracatinga (Mimosa scabrella) honeydew honey (BHH) from Santa Catarina (n = 15) and Paraná (n = 13) states (Brazil), followed by chemometric analysis for geographic discrimination. The FAA determination was performed by gas chromatography-mass spectrometry (GC-MS) after using a commercial EZ:faast™ kits for GC. Eight FAA were determined, being proline, asparagine, aspartic and glutamic acids found in all BHH, with significant differences (p < 0.05). In addition, with the exception of proline, the others FAA (asparagine, aspartic and glutamic) normally showed higher concentrations in samples from Santa Catarina state, being that in these samples it was also observed higher FAA sums (963.41 to 2034.73 mg kg-1) when compared to samples from Paraná state. The variability in the results did not show a clear profile of similarity when the heatmap and hierarchical grouping were correlated with the geographic origin and the concentration of eight determined FAA. However, principal component analysis (PCA) demonstrated that serine, asparagine, glutamic acid, and tryptophan were responsible for the geographic discrimination among samples from Santa Catarina and Paraná states, since they were the dominant variables (r > 0.72) in the PCA. Therefore, these results could be useful for the characterization and authentication of BHH based on their FAA composition and geographic origin.

Comparative floral development in Mimosa (Fabaceae: Caesalpinioideae) brings new insights into merism lability in the mimosoid clade.

The genus Mimosa L. (Leguminosae; Caesalpinioideae; mimosoid clade), comprising more than 500 species, is an intriguing genus because, like other members of the mimosoid clade, it presents an enormous variation in floral characteristics and high merism lability. Thus, this study aimed to elucidate the floral development and identify which ontogenetic pathways give rise to merism variation and andromonoecy in Mimosa caesalpiniifolia, M. pudica, M. bimucronata, and M. candollei. Floral buds at various stages of development and flowers were collected, fixed, and processed for surface analysis (SEM). The development of the buds is synchronous in the inflorescences. Sepals appear simultaneously as individualized primordia in M. caesalpiniifolia and in reversed unidirectional order in M. bimucronata, with union and formation of an early ring-like calyx. Petal primordia appear in unidirectional order, with a noticeably elliptical shape in M. caesalpiniifolia. The wide merism variation in Mimosa results from the absence of organs from inception in the perianth and androecium whorls: in dimerous, trimerous, or tetramerous flowers, the additional organs primordia to compose the expected pentamerous flowers are not initiated. The haplostemonous androecium of M. pudica results from the absence of antepetalous stamens from inception. In the case of intraspecific variations (instabilities), there is no initiation and subsequent abortion of organs in the events of reduction in merosity. In addition, extra primordia are initiated in supernumerary cases. On the other hand, staminate flowers originate from the abortion of the carpel. Mimosa proved to be an excellent model for studying merism variation. The lability is associated with actinomorphic and rather congested flowers in the inflorescences. Our data, in association with others of previous studies, suggest that the high lability in merism appeared in clades that diverged later in the mimosoid clade. Thus, phylogenetic reconstruction studies are needed for more robust evolutionary inferences. The present investigation of ontogenetic processes was relevant to expand our understanding of floral evolution in the genus Mimosa and shed light on the unstable merism in the mimosoid clade.

Ecological implications of stomatal density and stomatal index in the adult stage of Mimosa L. (Leguminosae, Caesalpinioideae).

Differences in stomatal density (SD) and stomatal index (SI) are associated with the conditions of the environment in which they are distributed. Mimosa species are important elements in different plant communities, yet knowledge of the ecological implications of its stomatal characteristics is scarce. For this reason, SD and SI were determined in seven Mimosa species from different environments in this study. Five individuals per species were selected, and a sample of leaflets was obtained from each. Fifteen mature leaflets per individual were then extracted and observed by optical microscopy. SD, SI, epidermal cell density (ECD), and guard cell length (GCL) values were obtained. Differences between species were analyzed through a balanced analysis of variance test, and the correspondence between the stomatal characteristics and 21 climate variables was determined by canonical correspondence analysis. The species differed in all evaluated characteristics. It should be noted that only M. affinis showed differences between the leaflet surfaces. Both DE and ECD were negatively associated with altitude and solar radiation and positively with temperature and precipitation. SI was explained by temperature and seasonality of precipitation, and GCL by temperature oscillation and seasonality of precipitation. The results suggest that the stomatal characteristics of the leaflets confer resistance in the species to alterations in environmental conditions.

Do environmental stimuli modify sensitive plant (Mimosa pudica L.) risk assessment?

Although plants and animals both assess their environment and respond to stimuli, this reaction is considered a behavior in animals and a response in plants. Responses in plants are seen within various timescales- from the nanosecond stimuli is presented to a lifelong progression. Within this study, we bridge the gap between animal behavioral studies and plant response. Sensitive plants (Mimosa pudica L.) are an ideal subject for this due to the rapid closure of their primary leaflets when touched. We designed a multimodal, or stress combination, experiment to test two hypotheses with sensitive plants: if they could be distracted and if they would alter their risk assessment when exposed to external stimuli (wind and sound). To evaluate the distraction hypothesis, we measured an individual's latency to close, hypothesizing that if the plants were distracted, they would take longer to close. To evaluate the uncertain risk hypothesis, we quantified the latency to reopen, hypothesizing that if the plants were uncertain, they would take longer to reopen. We also quantified the number of pinnae closed on the selected stem to test for changes in risk assessment across treatments. We expected the unimodal treatments would distract or alter risk assessment, and the multimodal treatment would elicit an enhanced response. Multimodal stimuli had a significant effect on the number of pinnae closed before the tap, but we found no evidence that plants were distracted by any stimulus tested. We found that temperature had a significant effect on the latency to close, and that plants modified their risk assessment when exposed to experimental wind stimuli. By manipulating environmental stimuli, we found that sensitive plants trade-off energy and perceived risk much in the way that is commonly found in animals. Framing the study of plants' responses to environmental stimuli as behavioral questions may generate new insights.

Ultrasensitive MicroRNA Photoelectric Assay Based on a Mimosa-like CdS-NiS/Au Schottky Junction.

Seeking and constructing superior photoactive materials have the potential to improve the performance of photoelectrochemical (PEC) biosensors. In this work, we proposed a novel mimosa-like ternary inorganic composite with a significantly enhanced light-harvesting ability and photogenerated carrier separation rate. This ternary photoactive material was obtained via electrodeposition of gold nanoparticles (Au) on the surface of transition metal sulfide composite of CdS and NiS (CdS-NiS/Au). The experimental results showed that the high initial photocurrent was acquired on CdS-NiS/Au (68-fold higher than that of individual CdS) with the synergistic effect of p-n heterojunction, Schottky junction, and the eminent optical properties of gold nanoparticles. Meanwhile, using silver nanoclusters prepared by link DNA protection as an effective quencher, integrating the duplex-specific nuclease-assisted rolling circle amplification strategy, a "Signal ON" PEC biosensor was fabricated for the detection of microRNA 21 (miRNA 21). With the release of the quencher, the recovered photocurrent is able to achieve determination of miRNA 21 within the range from 10 aM to 1 pM with a detection limit down to 4.6 aM (3σ). Importantly, this work not only provides a superb idea for designing ternary inorganic heteromaterials with exceptional photoactive ability but also allows the detection of other biomarkers by selecting appropriate recognition units.

Unleashing NK- and CD8 T cells by combining monalizumab and trastuzumab for metastatic HER2-positive breast cancer: Results of the MIMOSA trial.

The large majority of patients with HER2-positive metastatic breast cancer (MBC) will eventually develop resistance to anti-HER2 therapy and die of this disease. Despite, relatively high levels of stromal tumor infiltrating lymphocytes (sTILs), PD1-blockade has only shown modest responses. Monalizumab targets the inhibitory immune checkpoint NKG2A, thereby unleashing NK- and CD8 T cells. We hypothesized that monalizumab synergizes with trastuzumab by promoting antibody-dependent cell-mediated cytotoxicity. In the phase II MIMOSA-trial, HER2-positive MBC patients were treated with trastuzumab and 750 mg monalizumab every two weeks. Following a Simon's two-stage design, 11 patients were included in stage I of the trial. Treatment was well tolerated with no dose-limiting toxicities. No objective responses were observed. Therefore, the MIMOSA-trial did not meet its primary endpoint. In summary, despite the strong preclinical rationale, the novel combination of monalizumab and trastuzumab does not induce objective responses in heavily pre-treated HER2-positive MBC patients.

Effects of Mimosa caesalpiniifolia pre-formulation on the intestinal barrier during sodium dextran sulfate-induced colitis in Wistar rats / Efectos de la preformulación de Mimosa caesalpiniifolia sobre la barrera intestinal durante la colitis inducida por sulfato de dextrano sódico en ratas Wistar

INTRODUCTION: Anti-inflammatories, immunosuppressants, and immunobiological are commonly used in the treatment of inflammatory bowel disease. However, some patients do not present an adequate response or lose effective response during the treatment. A recent study found a potential anti-inflammatory effect of the hydroalcoholic extract of Mimosa caesalpiniifolia on trinitrobenzene sulfonic acid-induced colitis in Wistar rats. OBJECTIVE: To evaluate the effects of M. caesalpiniifolia pre-formulation on the intestinal barrier using dextran sulfate sodium-induced colitis model. MATERIALS AND METHODS: Leaf extracts were prepared in 70% ethanol and dried with a Buchi B19 Mini-spray dryer using 20% Aerosil® solution. Thirty-two male Wistar rats were randomized into four groups: basal control, untreated colitis, pre-formulation control (125 mg/kg/day), and colitis treated with pre-formulation (125 mg/kg/day). Clinical activity index was recorded daily and all rats were euthanized on the ninth day. Colon fragments were fixed and processed for histological and ultrastructural analyses. Stool samples were collected and processed for analysis of the short-chain fatty acid. RESULTS: Treatment with the pre-formulation decreased the clinical activity (bloody diarrhea), inflammatory infiltrate, and the ulcers. Pre-formulation did not repair the epithelial barrier and there were no significant differences in the goblet cells index. There was a significant difference in butyrate levels in the rats treated with the pre-formulation. CONCLUSIONS: The pre-formulation minimized the clinical symptoms of colitis and intestinal inflammation, but did not minimize damage to the intestinal barrier.

Introducción: Los antiinflamatorios, inmunosupresores e inmunobiológicos se utilizan comúnmente para tratar la enfermedad intestinal inflamatoria. Sin embargo, algunos pacientes no presentan una respuesta adecuada o pierden respuesta efectiva durante el tratamiento. En un estudio reciente, se encontró un potencial efecto antiinflamatorio del extracto hidroalcohólico de Mimosa caesalpiniifolia en la colitis inducida por el ácido trinitrobenceno sulfónico utilizando ratas Wistar. Objetivo: Evaluar los efectos de la preformulación de M. caesalpiniifolia sobre la barrera intestinal durante la colitis inducida por sulfato de dextrano sódico. Materiales y métodos: Los extractos de hojas se prepararon con una solución que contenía 70 % de etanol y se secaron con un secador por aspersión Mini B19 de Buchi usando una solución con 20 % de Aerosil®. Treinta y dos ratas Wistar macho se aleatorizaron en cuatro grupos: control basal, colitis sin tratar, control con preformulación (125 mg/kg/día) y colitis tratada con preformulación (125 mg/kg/día). El índice de actividad clínica se registró diariamente y todas las ratas se sacrificaron el noveno día. Los fragmentos de colon se fijaron y se procesaron para análisis histológicos y ultraestructurales. Se recolectaron muestras de heces y se procesaron para el análisis de ácidos grasos de cadena corta. Resultados: El tratamiento con la preformulación disminuyó la actividad clínica (diarrea sanguinolenta), el infiltrado inflamatorio y las úlceras. La preformulación no reparó la barrera epitelial y no hubo diferencias significativas en el índice de células caliciformes. Se obtuvo una diferencia significativa en los niveles de butirato en las ratas tratadas con la preformulación. Conclusiones: La preformulación minimizó los síntomas clínicos de colitis e inflamación intestinal pero no minimizó el daño a la barrera intestinal.

Effects of Mimosa caesalpiniifolia pre-formulation on the intestinal barrier during sodium dextran sulfate-induced colitis in Wistar rats / Efectos de la preformulación de Mimosa caesalpiniifolia sobre la barrera intestinal durante la colitis inducida por sulfato de dextrano sódico en ratas Wistar

Introduction. Anti-inflammatories, immunosuppressants, and immunobiological are commonly used in the treatment of inflammatory bowel disease. However, some patients do not present an adequate response or lose effective response during the treatment. A recent study found a potential anti-inflammatory effect of the hydroalcoholic extract of Mimosa caesalpiniifolia on trinitrobenzene sulfonic acid-induced colitis in Wistar rats. Objective. To evaluate the effects of M. caesalpiniifolia pre-formulation on the intestinal barrier using dextran sulfate sodium-induced colitis model. Materials and methods. Leaf extracts were prepared in 70% ethanol and dried with a Buchi B19 Mini-spray dryer using 20% Aerosil® solution. Thirty-two male Wistar rats were randomized into four groups: basal control, untreated colitis, pre-formulation control (125 mg/kg/day), and colitis treated with pre-formulation (125 mg/kg/day). Clinical activity index was recorded daily and all rats were euthanized on the ninth day. Colon fragments were fixed and processed for histological and ultrastructural analyses. Stool samples were collected and processed for analysis of the short-chain fatty acid. Results. Treatment with the pre-formulation decreased the clinical activity (bloody diarrhea), inflammatory infiltrate, and the ulcers. Pre-formulation did not repair the epithelial barrier and there were no significant differences in the goblet cells index. There was a significant difference in butyrate levels in the rats treated with the pre-formulation. Conclusions. The pre-formulation minimized the clinical symptoms of colitis and intestinal inflammation, but did not minimize damage to the intestinal barrier.

Introducción. Los antiinflamatorios, inmunosupresores e inmunobiológicos se utilizan comúnmente para tratar la enfermedad intestinal inflamatoria. Sin embargo, algunos pacientes no presentan una respuesta adecuada o pierden respuesta efectiva durante el tratamiento. En un estudio reciente, se encontró un potencial efecto antiinflamatorio del extracto hidroalcohólico de Mimosa caesalpiniifolia en la colitis inducida por el ácido trinitrobenceno sulfónico utilizando ratas Wistar. Objetivo. Evaluar los efectos de la preformulación de M. caesalpiniifolia sobre la barrera intestinal durante la colitis inducida por sulfato de dextrano sódico. Materiales y métodos. Los extractos de hojas se prepararon con una solución que contenía 70 % de etanol y se secaron con un secador por aspersión Mini B19 de Buchi usando una solución con 20 % de Aerosil®. Treinta y dos ratas Wistar macho se aleatorizaron en cuatro grupos: control basal, colitis sin tratar, control con preformulación (125 mg/kg/ día) y colitis tratada con preformulación (125 mg/kg/día). El índice de actividad clínica se registró diariamente y todas las ratas se sacrificaron el noveno día. Los fragmentos de colon se fijaron y se procesaron para análisis histológicos y ultraestructurales. Se recolectaron muestras de heces y se procesaron para el análisis de ácidos grasos de cadena corta. Resultados. El tratamiento con la preformulación disminuyó la actividad clínica (diarrea sanguinolenta), el infiltrado inflamatorio y las úlceras. La preformulación no reparó la barrera epitelial y no hubo diferencias significativas en el índice de células caliciformes. Se obtuvo una diferencia significativa en los niveles de butirato en las ratas tratadas con la preformulación. Conclusiones: La preformulación minimizó los síntomas clínicos de colitis e inflamación intestinal pero no minimizó el daño a la barrera intestinal.

Sensitive Timing: A Reappraisal of Chronobiology's Foundational Texts.

The origin of experimental chronobiology can be traced to observations made in the 18th and 19th centuries on the sensitive plant Mimosa, which were described in two seminal reports: Jean-Jacques d'Ortous de Mairan's "Observation Botanique" (A Botanical Observation) and Augustin Pyramus de Candolle's "Du sommeil des feuilles" (On the sleep of leaves). Both report observations of the striking daily closing and opening of Mimosa leaves in controlled environments. This review presents translations of both texts with the aim of staying as faithful as possible to the original French texts. We also present the historical context in which these texts were written and link them to subsequent experiments that aimed at testing the veracity of their central conclusions. In particular, we definitely establish that Mairan himself presented his work to the French Royal Academy of Sciences, while the published report of his observation was authored by Fontenelle, the Secretary of the Academy. In addition, we offer a translation of Mairan's own presentation, based on the hand-written minutes of the academy. Finally, we discuss the decades of work on plant rhythms that laid the foundation for modern experimental chronobiology, including translations and discussion of the insightful and prescient reports by Charles François de Cisternay Dufay, Henri Louis Duhamel du Monceau, Johann Gottfried Zinn, and Wilhelm Pfeffer, which describe their efforts to reproduce and extend Mairan's pioneering observations.

Summation of activation at the branch-stem transition of Mimosa pudica; a comparison with summation in cardiac tissue.

In Mimosa pudica plants, local and global responses to environmental stimuli are associated with different types of electrical activity. Non-damaging stimuli (e.g. cooling) generate action potentials (APs), whereas damaging stimuli (e.g. heating) are associated with variation potentials (VPs). Local cooling of Mimosa branches resulted in APs that propagated up to the branch-stem interface and caused drooping of the branch (local response). This electrical activation did not pass the interface. If the branch was triggered by heat, however, a VP was transferred to the stem and caused activation of the entire plant (global response). VPs caused by heat were always preceded by APs and summation of the two types of activation appeared to be necessary for the activation to pass the branch-stem interface. Mechanical cutting of leaves also resulted in VPs preceded by APs, but in those cases a time delay was present between the two activations, which prevented adequate summation and transmission of activation. Simultaneous cold-induced activation of a branch and the stem below the interface occasionally resulted in summation sufficient to activate the stem beyond the interface. To investigate the effect of activation delay on summation, a similar structure of excitable converging pathways, consisting of a star-shaped pattern of neonatal rat heart cells, was used. In this model, summation of activation was not hindered by a small degree of asynchrony. The observations indicate that summation occurs in excitable branching structures and suggest that summation of activation plays a role in the propagation of nocuous stimuli in Mimosa.

Malicia honey (Mimosa quadrivalvis L.) produced by the jandaíra bee (Melipona subnitida D.) improves depressive-like behaviour, somatic, biochemical and inflammatory parameters of obese rats.

Malícia honey produced by the jandaíra bee has hypoglycaemic and hypolipidemic effects and antioxidant activity in vitro and in vivo, which makes it potential adjuvant treatment for obesity. This study aimed to evaluate the effects of malícia honey on somatic and biochemical parameters, depressive-like behaviour and anti-inflammatory activity in obese rats. A total of 40 adult male Wistar rats were initially randomized into a healthy group (HG, n = 20) that consumed a control diet, and an obese group (OG, n = 20) which consumed a cafeteria diet for eight weeks. Then, they were subdivided into four groups: healthy (HG, n = 10); healthy treated with malícia honey (HGH, n = 10); obese (OG, n = 10); and obese treated with malícia honey (OGH, n = 10), maintaining their diets for another eight weeks. The HGH and OGH groups received malícia honey (1000 mg/kg body weight) via gavage. Food intake was monitored daily and body weight was monitored weekly. Biochemical tests related to obesity and glucose and insulin tolerance test, somatic parameters, histological parameters and quantification of NF-κB in the brain were performed. Treatment with malícia honey improved depressive-like behaviour, reduced weight (14 %), body mass index (6 %), and improved lipid profile, leptin, insulin, HOMA-ß, and glucose and insulin tolerance in obese rats. It also decreased NF-κB (58.08 %) in the brain. Malícia honey demonstrated anti-obesity and anti-inflammatory effects, and reversed changes in obesity-induced depressive-like behaviour.

Multiscale structural anisotropy steers plant organ actuation.

Leaf movement in vascular plants is executed by joint-like structures called pulvini. Many structural features of pulvini have been described at subcellular, cellular, and tissue scales of organization; however, how the characteristic hierarchical architecture of plant tissue influences pulvinus-mediated actuation remains poorly understood. To investigate the influence of multiscale structure on turgor-driven pulvinus movements, we visualized Mimosa pudica pulvinus morphology and anatomy at multiple hierarchical scales of organization and used osmotic perturbations to experimentally swell pulvini in incremental states of dissection. We observed directional cellulose microfibril reinforcement, oblong, spindle-shaped primary pit fields, and longitudinally slightly compressed cell geometries in the parenchyma of M. pudica. Consistent with these observations, isolated parenchyma tissues displayed highly anisotropic swelling behaviors indicating a high degree of mechanical anisotropy. Swelling behaviors at higher scales of pulvinus organization were also influenced by the presence of the pulvinus epidermis, which displayed oblong epidermal cells oriented transverse to the pulvinus long axis. Our findings indicate that structural specializations spanning multiple hierarchical scales of organization guide hydraulic deformation of pulvini, suggesting that multiscale mechanics are crucial to the translation of cell-level turgor variations into organ-scale pulvinus motion in vivo.

Investigating the Unique Ability of Trichodesmium To Fix Carbon and Nitrogen Simultaneously Using MiMoSA.

The open ocean is an extremely competitive environment, partially due to the dearth of nutrients. Trichodesmium erythraeum, a marine diazotrophic cyanobacterium, is a keystone species in the ocean due to its ability to fix nitrogen and leak 30 to 50% into the surrounding environment, providing a valuable source of a necessary macronutrient to other species. While there are other diazotrophic cyanobacteria that play an important role in the marine nitrogen cycle, Trichodesmium is unique in its ability to fix both carbon and nitrogen simultaneously during the day without the use of specialized cells called heterocysts to protect nitrogenase from oxygen. Here, we use the advanced modeling framework called multiscale multiobjective systems analysis (MiMoSA) to investigate how Trichodesmium erythraeum can reduce dimolecular nitrogen to ammonium in the presence of oxygen. Our simulations indicate that nitrogenase inhibition is best modeled as Michealis-Menten competitive inhibition and that cells along the filament maintain microaerobia using high flux through Mehler reactions in order to protect nitrogenase from oxygen. We also examined the effect of location on metabolic flux and found that cells at the end of filaments operate in distinctly different metabolic modes than internal cells despite both operating in a photoautotrophic mode. These results give us important insight into how this species is able to operate photosynthesis and nitrogen fixation simultaneously, giving it a distinct advantage over other diazotrophic cyanobacteria because they can harvest light directly to fuel the energy demand of nitrogen fixation. IMPORTANCE Trichodesmium erythraeum is a marine cyanobacterium responsible for approximately half of all biologically fixed nitrogen, making it an integral part of the global nitrogen cycle. Interestingly, unlike other nitrogen-fixing cyanobacteria, Trichodesmium does not use temporal or spatial separation to protect nitrogenase from oxygen poisoning; instead, it operates photosynthesis and nitrogen fixation reactions simultaneously during the day. Unfortunately, the exact mechanism the cells utilize to operate carbon and nitrogen fixation simultaneously is unknown. Here, we use an advanced metabolic modeling framework to investigate and identify the most likely mechanisms Trichodesmium uses to protect nitrogenase from oxygen. The model predicts that cells operate in a microaerobic mode, using both respiratory and Mehler reactions to dramatically reduce intracellular oxygen concentrations.