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Earth harbours an extraordinary plant phenotypic diversity1 that is at risk from ongoing global changes2,3. However, it remains unknown how increasing aridity and livestock grazing pressure-two major drivers of global change4-6-shape the trait covariation that underlies plant phenotypic diversity1,7. Here we assessed how covariation among 20 chemical and morphological traits responds to aridity and grazing pressure within global drylands. Our analysis involved 133,769 trait measurements spanning 1,347 observations of 301 perennial plant species surveyed across 326 plots from 6 continents. Crossing an aridity threshold of approximately 0.7 (close to the transition between semi-arid and arid zones) led to an unexpected 88% increase in trait diversity. This threshold appeared in the presence of grazers, and moved toward lower aridity levels with increasing grazing pressure. Moreover, 57% of observed trait diversity occurred only in the most arid and grazed drylands, highlighting the phenotypic uniqueness of these extreme environments. Our work indicates that drylands act as a global reservoir of plant phenotypic diversity and challenge the pervasive view that harsh environmental conditions reduce plant trait diversity8-10. They also highlight that many alternative strategies may enable plants to cope with increases in environmental stress induced by climate change and land-use intensification.
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Climate change is increasing the frequency and severity of short-term (~1 y) drought events-the most common duration of drought-globally. Yet the impact of this intensification of drought on ecosystem functioning remains poorly resolved. This is due in part to the widely disparate approaches ecologists have employed to study drought, variation in the severity and duration of drought studied, and differences among ecosystems in vegetation, edaphic and climatic attributes that can mediate drought impacts. To overcome these problems and better identify the factors that modulate drought responses, we used a coordinated distributed experiment to quantify the impact of short-term drought on grassland and shrubland ecosystems. With a standardized approach, we imposed ~a single year of drought at 100 sites on six continents. Here we show that loss of a foundational ecosystem function-aboveground net primary production (ANPP)-was 60% greater at sites that experienced statistically extreme drought (1-in-100-y event) vs. those sites where drought was nominal (historically more common) in magnitude (35% vs. 21%, respectively). This reduction in a key carbon cycle process with a single year of extreme drought greatly exceeds previously reported losses for grasslands and shrublands. Our global experiment also revealed high variability in drought response but that relative reductions in ANPP were greater in drier ecosystems and those with fewer plant species. Overall, our results demonstrate with unprecedented rigor that the global impacts of projected increases in drought severity have been significantly underestimated and that drier and less diverse sites are likely to be most vulnerable to extreme drought.
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Sequías , Ecosistema , Pradera , Ciclo del Carbono , Cambio Climático , Proteínas Tirosina Quinasas ReceptorasRESUMEN
Research in global change ecology relies heavily on global climatic grids derived from estimates of air temperature in open areas at around 2 m above the ground. These climatic grids do not reflect conditions below vegetation canopies and near the ground surface, where critical ecosystem functions occur and most terrestrial species reside. Here, we provide global maps of soil temperature and bioclimatic variables at a 1-km2 resolution for 0-5 and 5-15 cm soil depth. These maps were created by calculating the difference (i.e. offset) between in situ soil temperature measurements, based on time series from over 1200 1-km2 pixels (summarized from 8519 unique temperature sensors) across all the world's major terrestrial biomes, and coarse-grained air temperature estimates from ERA5-Land (an atmospheric reanalysis by the European Centre for Medium-Range Weather Forecasts). We show that mean annual soil temperature differs markedly from the corresponding gridded air temperature, by up to 10°C (mean = 3.0 ± 2.1°C), with substantial variation across biomes and seasons. Over the year, soils in cold and/or dry biomes are substantially warmer (+3.6 ± 2.3°C) than gridded air temperature, whereas soils in warm and humid environments are on average slightly cooler (-0.7 ± 2.3°C). The observed substantial and biome-specific offsets emphasize that the projected impacts of climate and climate change on near-surface biodiversity and ecosystem functioning are inaccurately assessed when air rather than soil temperature is used, especially in cold environments. The global soil-related bioclimatic variables provided here are an important step forward for any application in ecology and related disciplines. Nevertheless, we highlight the need to fill remaining geographic gaps by collecting more in situ measurements of microclimate conditions to further enhance the spatiotemporal resolution of global soil temperature products for ecological applications.
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Ecosistema , Suelo , Cambio Climático , Microclima , TemperaturaRESUMEN
Poorly water-soluble drugs like sorafenib tosylate (SFB) can be made more soluble and orally bioavailable using a biocompatible hydrophilic matrix yields amorphous or microcrystalline drugs with high stability and low recrystallization risk. Mesoporous starch (MPS) due to its edibility, biodegradability, high surface area, and confined pores. In this study, MPS, either alone or in combination with polyvinylpyrrolidone (PVP), was employed for improving SFB oral bioavailability. To this aim, MPS was prepared in three steps: gelatinization, solvent exchange, and vacuum drying, after which it was used to incorporate SFB at various ratios using the immersion/solvent evaporation technique. Nitrogen adsorption/desorption analysis, Fourier transform infrared spectrometry (FTIR), field emission scanning electron microscopy (FE-SEM), powder X-ray diffraction (XRD) crystallography, and differential scanning calorimetry (DSC) were used to characterize SFB-loaded and drug-free samples, which confirmed the successful preparation of mesoporous structures with desirable uniform porosity, small pore size (about 5.3 nm), and specific surface area of about 24 m2/g. In-vitro dissolution testing revealed that the SFB dissolution rate increased substantially for the loaded MPS or MPS-PVP samples. Furthermore, when SFB was loaded in MPS-PVP, single-dose pharmacokinetics in rats confirmed an enhanced oral absorption kinetic. Therefore, impregnation of poorly soluble drugs such as SFB in the PVP-modified MPS excipient, which is constructed from a combination of mesoporous materials and a drug recrystallization inhibitor such as hydrophilic polymers, is proposed as a promising strategy for desirable enhancements in drug solubility, oral bioavailability, and efficacy.
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Portadores de Fármacos , Almidón , Ratas , Animales , Disponibilidad Biológica , Almidón/química , Sorafenib , Portadores de Fármacos/química , Administración Oral , Solventes/química , PovidonaRESUMEN
Plant traits-the morphological, anatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives.
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Acceso a la Información , Ecosistema , Biodiversidad , Ecología , PlantasRESUMEN
OBJECTIVE: The effect of voglibose on metabolic homeostasis is not well characterized. Therefore, we conducted a systematic review and meta-analysis of clinical trials assessing the effect of voglibose on metabolic profile in patients with type 2 diabetes mellitus (T2DM). METHODS: Systematic searches were conducted in PubMed, Scopus, Embase, Google Scholar, Web of Science and Cochrane Library to identify clinical trials assessing the effects of voglibose supplementation on cardio-metabolic profile from incept up to 29 July 2019. Data was pooled using fixed- or random-effect models and weighted mean difference (WMD) as the effect size. RESULTS: Eight clinical trials from 1094 reports, were eligible for inclusion. Pooled findings identified significant reductions in hemoglobin A1c (HbA1c) (WMD= -0.27; 95 %CI -0.49 to -0.05; P = 0.01; I2 = 64.8 %) and an increase in LDL-cholesterol levels (WMD=5.97 mg/dl, 95 % CI 0.88, 11.06, P = 0.02; I2 = 0.0 %). However, no evidence of effect for voglibose intake on T2DM patients was observed for: fasting blood sugar (FBS) (WMD -7.43 mg/dl; 95 %CI -16.56 to 1.71; P = 0.110; I2 = 69.3 %), serum insulin (WMD= -0.15 µU/mL; 95 %CI -0.89 to 0.60; P = 0.70; I2 = 0.0 %), total-cholesterol (WMD=2.82 mg/dl, 95 %CI -2.36 to 8.01, P = 0.70; I2 = 49.7 %), triglycerides (WMD= -7.07 mg/dl, 95 %CI -21.76 to 7.62, P = 0.34; I2 = 0.0 %), HDL-cholesterol levels (WMD= -2.10 mg/dl, 95 %CI -4.48 to 0.27, P = 0.08; I2 = 0.0 %,), body mass index (BMI) (WMD=0.09 kg/m2, 95 %CI -0.70 to 0.87; P = 0.87; I2 = 0.0 %), body weight (WMD= -0.42 kg, 95 %CI -0.84 to 0.00; P = 0.05; I2 = 0.0 %), and adiponectin levels (WMD = 0.32 µg/mL, 95 %CI -0.74 to 1.38; P = 0.55; I2 = 0.0 %). CONCLUSIONS: The current meta-analysis identified a decrease in HbA1c and an increase in LDL-cholesterol with administration of voglibose. However, no significant effect was observed on FBS, insulin, bodyweight, BMI, adiponectin, triglycerides, total- and HDL-cholesterol levels.
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Diabetes Mellitus Tipo 2/tratamiento farmacológico , Metabolismo Energético/efectos de los fármacos , Inhibidores de Glicósido Hidrolasas/uso terapéutico , Inositol/análogos & derivados , Anciano , Biomarcadores/sangre , LDL-Colesterol/sangre , Diabetes Mellitus Tipo 2/sangre , Diabetes Mellitus Tipo 2/diagnóstico , Femenino , Hemoglobina Glucada/metabolismo , Inhibidores de Glicósido Hidrolasas/efectos adversos , Humanos , Inositol/efectos adversos , Inositol/uso terapéutico , Masculino , Persona de Mediana Edad , Ensayos Clínicos Controlados Aleatorios como Asunto , Resultado del TratamientoRESUMEN
Albendazole is known as the drug of choice for medical treatment of cystic echinococcosis (CE). Albendazole sulfoxide (ABZ-SO), as the main active metabolite of albendazole, has low efficacy in the disease due to low water solubility and poor absorptivity. PLGA nanoparticles (NPs) enhance the dissolution of poorly soluble drugs, and chitosan (CS) coating enhances oral drug delivery of NPs. In this study, the efficacy of ABZ-SO-loaded CS-PGLA NPs in the treatment of CE was evaluated in laboratory mice. ABZ-SO-loaded CS-PGLA NPs were prepared by nanoprecipitation and characterized by dynamic light scattering method and scanning electron microscopy. Thirty mice were intraperitoneally infected by 1000 protoscoleces of Echinococcus granulosus. Ten months later, the mice were allocated into 3 groups: groups 1 and 2 were treated with ABZ-SO and ABZ-SO-loaded CS-PGLA NPs, respectively, and the mice in group 3 remained untreated as the control group. The drugs were administered by gavage for 45 days at a daily dose of 10 mg/kg. Finally, all mice were opened and the cysts were collected, counted, weighed, and measured separately. The therapeutic effect of ABZ-SO in the number, weight, and volume of the cysts were not statistically significant compared with those in ABZ-SO-loaded CS-PGLA NPs and the control group. However, the therapeutic effect of ABZ-SO-loaded CS-PGLA NPs in the weight and volume of cysts were statistically significant when compared with that in the control group (p Ë 0.05). In conclusions, this study revealed that ABZ-SO-loaded CS-PGLA NPs could enhance the therapeutic efficacy of ABZ-SO in the treatment of CE in laboratory mice.
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Albendazol/análogos & derivados , Antiplatelmínticos/administración & dosificación , Quitosano/química , Equinococosis/tratamiento farmacológico , Ácido Poliglicólico/química , Administración Oral , Albendazol/administración & dosificación , Albendazol/química , Animales , Antiplatelmínticos/química , Quitosano/administración & dosificación , Sistemas de Liberación de Medicamentos , Evaluación Preclínica de Medicamentos , Echinococcus granulosus/efectos de los fármacos , Ratones , Nanopartículas/administración & dosificación , Nanopartículas/química , Ácido Poliglicólico/administración & dosificaciónRESUMEN
Several studies have revealed that healthcare nanomaterials are widely used in numerous areas of dentistry, including prevention, diagnosis, treatment, and repair. Nanomaterials in dental cosmetics are utilized to enhance the efficacy of toothpaste and other mouthwashes. Nanoparticles are added to toothpastes for a variety of reasons, including dental decay prevention, remineralization, hypersensitivity reduction, brightening, and antibacterial qualities. In this review, the benefits and uses of many common nanomaterials found in toothpaste are outlined. Additionally, the capacity and clinical applications of nanoparticles as anti-bacterial, whitening, hypersensitivity, and remineralizing agents in the treatment of dental problems and periodontitis are discussed.
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BACKGROUND: Acne is a common skin issue that typically occurs during adolescence. It causes long-lasting redness and swelling in the skin. An alternative approach to treating acne could involve using a cosmetic facial mask containing herbal ingredients such as Curcumin and Rosa Damascena extract for its antibacterial properties. AIMS: This study aims to create and try out a peel-off mask gel made from Curcumin and R. Damascena extract. This gel is intended to have the ability to kill bacteria such as Staphylococcus aureus, Escherichia coli, and Propionibacterium acnes and remove dead cells from the skin surface. METHODS: The peel-off mask was made using polyvinyl alcohol (PVA) in 8% and 10% as solidifier. The evaluation of peel-off masks comprises the examination of physiochemical and mechanical aspects. Furthermore, their longevity, effectiveness, and antibacterial properties are also considered. RESULTS: The white color, pleasant smell, and soft texture were the defining features of the peel-off gel mask. The changes in PVA affect the pH level, thickness, and how quickly the peel-off mask dries. The stability test found that the peel-off mask had no significant physical changes when exposed to freezing and thawing. However, there were some differences in color and separation when using the real-time method. A prepared peel-off mask containing 10% PVA and curcumin works best against P. acne. The amount of PVA in the formula affected the physical and chemical qualities, but it did not impact on the antibacterial abilities of the peel-off mask gel. The best formula that gives the best results uses 10% PVA + curcumin. CONCLUSIONS: Using the Curcumin and R. Damascena extract in the creation of the peel-off mask gel ensures its efficacy and safety for skin application.
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Acné Vulgar , Antibacterianos , Antioxidantes , Curcumina , Extractos Vegetales , Rosa , Staphylococcus aureus , Curcumina/farmacología , Curcumina/administración & dosificación , Extractos Vegetales/farmacología , Extractos Vegetales/administración & dosificación , Extractos Vegetales/química , Rosa/química , Humanos , Antibacterianos/farmacología , Antibacterianos/administración & dosificación , Antioxidantes/farmacología , Antioxidantes/administración & dosificación , Acné Vulgar/tratamiento farmacológico , Acné Vulgar/microbiología , Staphylococcus aureus/efectos de los fármacos , Propionibacterium acnes/efectos de los fármacos , Alcohol Polivinílico/química , Escherichia coli/efectos de los fármacos , Crema para la Piel/administración & dosificación , Piel/efectos de los fármacos , Piel/microbiología , Pruebas de Sensibilidad MicrobianaRESUMEN
The development of biocompatible wound dressings containing therapeutic agents to accelerate wound healing is an interesting field of study in biomedical sciences. Polyvinyl alcohol (PVA) nanofibers were loaded with zinc oxide nanoparticles (ZnO NPs) and curcumin (Cur) through electrospinning. The dressings were characterized by SEM and XRD and FTIR. The antioxidant, antibacterial, and cytotoxic activities Cur/ZnO/PVA nano dressing were evaluated using DPPH radical scavenging assay, disc diffusion method, and MTT assay, respectively. Cur/ZnO/PVA nano dressing showed sustained Cur release about 19.7% and 61.1% after 8h and 168h, respectively. Cur/ZnO NPs/PVA mixture had higher antioxidant potential than PVA, ZnO NPs, and Cur. The dressing showed a good antibacterial effect. The in vivo wound healing effect of different types of prepared dressings, including PVA, Cur/PVA, Cur/ZnO/PVA, and ZnO/ PVA nanofibers, was also investigated. PVA dressing containing Cur/ZnO NPs resulted in the highest increase of wound contraction in rats. The assembly of Cur and ZnO NPs on PVA nanofibers could propose as an effective delivery method to improve the wound healing process. The investigated wound dressing could be commercialized and used on a large scale after proper further studies, including clinical trials.
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Theranostics nanoparticles (NPs) have recently received much attention in cancer imaging and treatment. This study aimed to develop a multifunctional nanosystem for the targeted delivery of photothermal and chemotherapy agents. Fe3O4 NPs were modified with polydopamine, bovine serum albumin, and loaded with DOX via a thermal-cleavable Azo linker (Fe3O4@PDA@BSA-DOX). The size of Fe3O4@PDA@BSA NPs was approximately 98 nm under the desired conditions. Because of the ability of Fe3O4 and PDA to convert light into heat, the temperature of Fe3O4@PDA@BSA NPs increased to approximately 47 °C within 10 min when exposed to an 808 nm NIR laser with a power density of 1.5 W/cm2. The heat generated by the NIR laser leads to the breaking of AZO linker and drug release. In vivo and in vitro results demonstrated that prepared NPs under laser irradiation successfully eradicated tumor cells without any significant toxicity effect. Moreover, the Fe3O4@PDA@BSA NPs exhibited the potential to function as a contrasting agent. These NPs could accumulate in tumors with the help of an external magnet, resulting in a significant enhancement in the quality of magnetic resonance imaging (MRI). The prepared novel multifunctional NPs seem to be an efficient system for imaging and combination therapy in melanoma.
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Compuestos Férricos , Indoles , Melanoma , Polímeros , Humanos , Melanoma/tratamiento farmacológico , Terapia Fototérmica , Medicina de Precisión , Fototerapia/métodos , Doxorrubicina/farmacología , Doxorrubicina/uso terapéutico , Rayos LáserRESUMEN
Perennial plants create productive and biodiverse hotspots, known as fertile islands, beneath their canopies. These hotspots largely determine the structure and functioning of drylands worldwide. Despite their ubiquity, the factors controlling fertile islands under conditions of contrasting grazing by livestock, the most prevalent land use in drylands, remain virtually unknown. Here we evaluated the relative importance of grazing pressure and herbivore type, climate and plant functional traits on 24 soil physical and chemical attributes that represent proxies of key ecosystem services related to decomposition, soil fertility, and soil and water conservation. To do this, we conducted a standardized global survey of 288 plots at 88 sites in 25 countries worldwide. We show that aridity and plant traits are the major factors associated with the magnitude of plant effects on fertile islands in grazed drylands worldwide. Grazing pressure had little influence on the capacity of plants to support fertile islands. Taller and wider shrubs and grasses supported stronger island effects. Stable and functional soils tended to be linked to species-rich sites with taller plants. Together, our findings dispel the notion that grazing pressure or herbivore type are linked to the formation or intensification of fertile islands in drylands. Rather, our study suggests that changes in aridity, and processes that alter island identity and therefore plant traits, will have marked effects on how perennial plants support and maintain the functioning of drylands in a more arid and grazed world.
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Herbivoria , Suelo , Suelo/química , Plantas , Ecosistema , Clima Desértico , AnimalesRESUMEN
Assisted reproductive technologies are key to solving the problems of aging and organ defects. Collagen is compatible with living tissues and has many different chemical properties; it has great potential for use in reproductive medicine and the engineering of reproductive tissues. It is a natural substance that has been used a lot in science and medicine. Collagen is a substance that can be obtained from many different animals. It can be made naturally or created using scientific methods. Using pure collagen has some drawbacks regarding its physical and chemical characteristics. Because of this, when collagen is processed in various ways, it can better meet the specific needs as a material for repairing tissues. In simpler terms, collagen can be used to help regenerate bones, cartilage, and skin. It can also be used in cardiovascular repair and other areas. There are different ways to process collagen, such as cross-linking it, making it more structured, adding minerals to it, or using it as a carrier for other substances. All of these methods help advance the field of tissue engineering. This review summarizes and discusses the current progress of collagen-based materials for reproductive medicine.
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The global prevalence of cancer is increasing, necessitating new additions to traditional treatments and diagnoses to address shortcomings such as ineffectiveness, complications, and high cost. In this context, nano and microparticulate carriers stand out due to their unique properties such as controlled release, higher bioavailability, and lower toxicity. Despite their popularity, they face several challenges including rapid liver uptake, low chemical stability in blood circulation, immunogenicity concerns, and acute adverse effects. Cell-mediated delivery systems are important topics to research because of their biocompatibility, biodegradability, prolonged delivery, high loading capacity, and targeted drug delivery capabilities. To date, a variety of cells including blood, immune, cancer, and stem cells, sperm, and bacteria have been combined with nanoparticles to develop efficient targeted cancer delivery or diagnosis systems. The review paper aimed to provide an overview of the potential applications of cell-based delivery systems in cancer therapy and diagnosis.
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Neoplasias , Semen , Masculino , Humanos , Nanotecnología , Neoplasias/diagnóstico , Neoplasias/tratamiento farmacológicoRESUMEN
Vegetation degradation can have significant effects on organic matter fractions as well as various soil characteristics. All these can lead to the changes in soil microbial communities, which are main drivers of nutrient cycles. This is especially important for mountainous ecosystems that are very sensitive and fragile habitats due to their climatic conditions, but less attention has been paid to them. Thus, Mirkola mountainous region (northern Iran) with semi-arid climate and vegetation being dominated by Crataegus and Berberis shrubs were investigated in this study. Sites with different intensities of vegetation degradation [light (60-70 % coverage), moderate (30-40 % coverage) and heavy (0-10 % coverage)] and also non-degraded control sites (90-100 % coverage) were selected. In order to avoid pseudoreplication, three plots, each with an area of 1 ha (100 m × 100 m), were used for each of the four studied habitats. Soil (in three soil depths at 0-10 cm, 10-20 cm and 20-30 cm) samples were collected from the corners and also the center (n = 5) of the plots using iron frames (30 × 30 cm). A total of 180 soil samples (4 habitats × 15 sample × 3 depths) were transferred to the laboratory. Labile and non-labile contents of soil organic matter (SOM) (C and N in soil particles and aggregates, C and N stocks, particulate and dissolved organic matter, hot-water extractable carbohydrate, C and N mineralization) were measured in each of these sites. Results showed that vegetation degradation might result in both labile and non-labile SOM losses. SOM and its associated properties were highest in the non-degraded sites, whereas, lower values were common under degraded areas. Based on the obtained data, vegetation cover can enhance the amount of organic matter entering the soil (especially in the surface layers) and formation of fertile islands in ecosystems. Accordingly, vegetation protection is emphasized to maintain stability and provide ecosystem services in mountainous semi-arid regions.
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Microbiota , Suelo , Ecosistema , Agua , Hierro , Carbohidratos , CarbonoRESUMEN
Soil biological properties are good indicators for the evaluation of soil quality, introduced as key indicators in soil health, which is in line with the nutrient cycles in terrestrial ecosystems. To the best of the authors' knowledge, responses of belowground biota to habitat degradation have received little attention. The present study aimed to study the effect of different intensities of vegetation degradation [heavy (0-10% coverage), moderate (30-40% coverage) and light (60-70% coverage)] and non-degraded sites (as control; 90-100% coverage) in lands covered by Crataegus and Berberis shrubs on soil fauna, microbiota and microbial activities in the north of Iran. From each of these sites, 45 soil (30 × 30 cm area) samples were taken from 0 to 10 cm, 10-20 cm and 20-30 cm depths and 180 samples were transferred to the laboratory. According to principal component analysis, the studied habitats can be distinguished based on soil health and functional characteristics. In this regard, due to the more fertile soil in ecosystems without degradation, highest soil biological activities belonged to these areas. Following the increase in the intensity of degradation, the population of soil organisms and microbial activities are suppressed due to reduction of organic matter inputs, unsuitable soil microclimate, increase in soil erosion and finally depletion of soil nutrients. The results of this study indicate the dependence of soil quality on aboveground vegetation cover, especially in the topsoil, so the vegetation degradation can cause severe damages to soil health in semi-arid regions.
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Ecosistema , Suelo , Biota , Clima Desértico , Microbiología del SueloRESUMEN
Although the diversity-disturbance relationship has been extensively studied, the differences in responses of taxonomic vs. functional diversity to natural disturbances (i.e., fire) call for an improved understanding of this relationship. Here, we investigated how fire disturbance influenced plant taxonomic and functional diversity in Golestan National Park, in northeastern Iran. We evaluated the response of α- and ß-plant diversity considering both taxonomic and functional diversity and different ß-diversity components (i.e., turnover and nestedness) as a function of fire regime, topographic exposure, and their interactive effect. We considered different indices of functional diversity including functional richness, functional evenness, functional divergence, functional dispersion, Rao's quadratic entropy, and community-weighted mean (CWM). Functional diversity indices were computed using four leaf traits related to species growth strategy and fire response including leaf thickness and leaf length, specific leaf area (SLA) and leaf dry matter content (LDMC). Taxonomic and functional diversity had contrasting response to fire disturbance. Fire significantly decreased taxonomic α-diversity similarly in both north and south exposures. ß-diversity increased in south exposures but decreased in north exposures. Fire decreased functional richness, increased CWM of SLA, and decreased CWM of LDMC. In contrast, abundance-weighted metrics of functional diversity (functional evenness, functional divergence, functional dispersion, Rao's quadratic entropy) were not impacted by fire disturbance. Finally, the main contributors to heterogeneity were driven by a fire × exposure interaction, suggesting that fire disturbance interacts with topographic exposure. Our results suggest that taxonomic and functional α- and ß-diversity have contrasting responses to fire illustrating the need to consider both dimensions to understand how disturbance impacts plant communities. At large spatial scale, species turnover and nestedness appear as essential parameters to maintain species-rich communities in response to fire disturbance.
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Salt marshes are unique habitats between sea or saline lakes and land that need to be conserved from the effects of global change. Understanding the variation in functional structure of plant community along environmental gradients is critical to predict the response of plant communities to ongoing environmental changes. We evaluated the changes in the functional structure of halophytic communities along soil gradients including salinity, in Iranian salt marshes; Lake Urmia, Lake Meyghan, Musa estuary, and Nayband Bay (Iran). We established 48 plots from 16 sites in four salt marshes and sampled 10 leaves per species to measure leaf functional traits. Five soil samples were sampled from each plot and 30 variables were analyzed. We examined the changes in the functional structure of plant communities (i.e., functional diversity [FD] and community weighted mean [CWM]) along local soil gradients using linear mixed effect models. Our results showed that FD and CWM of leaf thickness tended to increase with salinity, while those indices related to leaf shape decreased following soil potassium content. Our results suggest that the variations in functional structure of plant communities along local soil gradients reveal the effect of different ecological processes (e.g., niche differentiation related to the habitat heterogeneity) that drive the assembly of halophytic plant communities in SW Asian salt marshes.
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High-dose methotrexate (MTX) chemotherapeutic applications confront drug specificity and pharmacokinetic challenges, which can be overcome by utilizing targeted drug delivery systems. In the present study, biotin-PEG conjugated nanogels of carboxymethyl polyethyleneimine (Biotin-PEG-CMPEI) were developed for active targeted delivery of MTX in triple negative breast cancer (TNBC). TEM and DLS analyses revealed uniform, discrete, and spherical particles with a mean hydrodynamic diameter of about 100 nm and ζ-potential of + 15 mV (pH = 7.4). Biotin-PEG-CMPEI nanogels exhibited a zero-order MTX release kinetics at pH = 7.5 and a swelling-controlled release at pH = 5.5. In 4 T1 cells treated with the MTX-loaded Biotin-PEG-CMPEI, the IC50 was reduced by about 10 folds compared to the free drug, while the unloaded nanogels showed no significant toxicity. In the model mice, the group treated with the MTX-loaded Biotin-PEG-CMPEI had a lower tumor volume and mortality rate animal model when compared to free drug. Additionally, histopathological analyses showed that the group treated with the MTX-loaded nanogels had less lung metastasis and glomerular damage caused by MTX. Overall, the MTX-loaded Biotin-PEG-CMPEI targeted directly against overexpressed biotin receptors in TNBC have been shown to improve the MTX safety and therapeutic efficacy.
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Metotrexato , Neoplasias de la Mama Triple Negativas , Animales , Biotina , Portadores de Fármacos , Sistemas de Liberación de Medicamentos , Humanos , Ratones , Nanogeles , Receptores de Factores de Crecimiento , Neoplasias de la Mama Triple Negativas/tratamiento farmacológicoRESUMEN
Grazing represents the most extensive use of land worldwide. Yet its impacts on ecosystem services remain uncertain because pervasive interactions between grazing pressure, climate, soil properties, and biodiversity may occur but have never been addressed simultaneously. Using a standardized survey at 98 sites across six continents, we show that interactions between grazing pressure, climate, soil, and biodiversity are critical to explain the delivery of fundamental ecosystem services across drylands worldwide. Increasing grazing pressure reduced ecosystem service delivery in warmer and species-poor drylands, whereas positive effects of grazing were observed in colder and species-rich areas. Considering interactions between grazing and local abiotic and biotic factors is key for understanding the fate of dryland ecosystems under climate change and increasing human pressure.