Search

This study investigates the effects of grazing intensity and spatial scale on the important values, interspecific relationships, and community stability of desert steppe plant communities in Siziwang Banner, Inner Mongolia, China. Using vegetation data collected at three spatial scales (50 m × 50 m, 25 m × 25 m, and 2.5 m × 2.5 m) under two grazing conditions (no grazing and heavy grazing), we employed ecological statistics, including variance ratio analysis, χ 2 tests, and the Jaccard index, to analyze species interactions and community structure. The results indicated that the important values of species vary with both spatial scale and grazing intensity; for example, Stipa breviflori and Chenopodium aristatum exhibited significantly higher important values in heavily grazed areas. Larger spatial scales enhanced the dominance of Cleistogenes songorica and Chenopodium aristatum, while smaller scales favored Stipa breviflori and Caragana stenophylla. Furthermore, interspecific associations were stronger in heavy grazing conditions. The community demonstrated consistent instability; however, no grazing areas were more stable than heavily grazed ones. These findings highlight that species importance, interspecific relationships, and community stability are closely linked to grazing intensity and spatial scale, emphasizing the critical role of sustainable grazing management in maintaining the long-term stability and resilience of desert steppe ecosystems. By emphasizing the need for targeted and sustainable management strategies, this study aims to contribute to the restoration and preservation of these vital ecosystems. [ABSTRACT FROM AUTHOR]

Dominant species play a principal role in controlling and maintaining ecosystem stability. Stipa breviflora is the dominant species in desert steppe. Changes in the stability of a plant population will further affect the stability of the broader habitat, such as the desert steppe. In the desert steppe ecosystem, it is not clear what level of grazing intensity is best for improving the grazing tolerance and stability of the vegetation. And, the study of this question should involve a multi-dimensional, comprehensive analysis. This study will utilize variance analysis, plant population stability, and trade-off index to study S. breviflora, the dominant species in the desert steppe in Inner Mongolia, and its performance under four grazing intensities (control, CK, 0 sheep·ha−1·half year−1; light grazing, LG, 0.93 sheep·ha−1·half year−1; moderate grazing, MG, 1.82 sheep·ha−1·half year−1; and heavy grazing, HG, 2.71 sheep·ha−1·half year−1) over six scales (5 cm × 5 cm; 10 cm × 10 cm; 20 cm × 20 cm; 25 cm × 25 cm; 50 cm × 50 cm; and 100 cm × 100 cm). The characteristics of the population stability of S. breviflora were explored. The results showed that the response of S. breviflora's stability to heavy grazing was multidimensional. Heavy grazing reduced the population stability of S. breviflora. Across different dimensions, base coverage was the first of the population stability metrics of S. breviflora to destabilize, followed by projection coverage, density, and height. Heavy grazing also affected the trade-offs of S. breviflora's population stability across different dimensions. In general, the trade-off degree decreased as the grazing intensity increased, and it increased as the scale increased. [ABSTRACT FROM AUTHOR]

Antler velvet polypeptide (VAP) is a prominent bioactive component of antler velvet. Whereas uncharacterized crude extracts have typically been used in pharmacological studies, in this study, the velvet polypeptide was isolated and purified by acid water extraction, ethanol precipitation, ammonium sulfate fractionation and precipitation, and chromatography, progressively. Human umbilical vein endothelial cells (HUVECs) were induced with [H.sub.2][O.sub.2] followed purified polypeptide treatment. Cell viability was evaluated by MTT assay. The apoptosis of cells was detected by fluorescence microscopy and flow cytometry. A cell analyzer was used to measure the mitochondrial membrane potential. The intracellular reactive oxygen species (ROS) levels were determined by flow cytometry. Oxidative stress related biochemical parameters were detected, and the expression of apoptosis-related proteins was examined by Western blot analysis. The results indicated that a 7.0 kDa polypeptide (VAP II) was isolated from antler velvet. VAP II enhanced cell viability, decreased cell apoptosis, reversed depolarization of mitochondrial membrane potential, decreased ROS levels, inhibited oxidative stress, and regulated the downstream signaling apoptotic cascade expression caused by [H.sub.2][O.sub.2]. The protective effects of VAP II on HUVECs suggests a potential strategy for the treatment of cardiovascular disease. Key words: antler velvet polypeptides, oxidative stress, antioxidant, apoptosis. Le polypeptide de bois de velours (VAP pour << antler velvet polypeptide >>) est un important compose bioactif des bois de velours. Alors que des extraits bruts non caracterises ont habituellement ete utilises dans le cadre d'etudes pharmacologiques, dans cette etude, nous avons isole et purifie le polypeptide de velours par une extraction acide-eau, la precipitation dans l'ethanol ainsi que le fractionnement et la precipitation a l'aide de sulfate d'ammonium, avec le passage progressif dans une colonne de chromatographie. Nous avons obtenu des cellules HUVEC (pour << human umbilical vein endothelial cells >>) par une induction l'aide de [H.sub.2][O.sub.2] suivie d'un traitement de purification des polypeptides. Nous avons evalue la viabilite des cellules l'aide du test MTT. Nous avons decele les cellules apoptotiques a l'aide de la microscopie par fluorescence et de la cytometrie en flux. Nous avons utilise un analyseur de cellules pour mesurer le potentiel des membranes mitochondriales. Nous avons mesure les derives reactifs de l'oxygene (ou ROS pour << reactive oxygen species >>) intracellulaires par cytometrie en flux. Nous avons detecte les parametres biochimiques lies au stress oxydatif et etudie l'expression des proteines liees a l'apoptose a l'aide de la technique d'immunobuvardage de Western. Les resultats ont revele l'isolation d'un polypeptide de 7,0 kDa (VAP II) partir de bois de velours. Le VAP II pourrait entrainer une augmentation de la viabilite des cellules, une attenuation de l'apoptose cellulaire, la depolarisation inverse du potentiel des membranes mitochondriales, diminuer les taux de ROS, inhiber le stress oxydatif et assurer la regulation de l'expression de la cascade de la signalisation apoptotique causee par le [H.sub.2][O.sub.2] en aval. Les effets protecteurs du VAP II contre les lesions des cellules HUVEC ont permis d'obtenir une strategie eventuelle dans le traitement de la maladie cardiovasculaire. [Traduit par la Redaction] Mots-cles : polypeptide de bois de velours, stress oxydatif, antioxydant, apoptose., Introduction There has recently been a surge of interest in the benefits from the natural products used in traditional and herbal medicines. To date, the majority of studies conducted worldwide [...]

Leymus chinensis is a widely distributed species of Eurasian grasslands that is well adapted to a range of environmental conditions. In this study, we measured soil and plant chemical elements to examine the basis of the ecological adaptations of L. chinensis to temperate steppe. We sampled leaves of L. chinensis and soil layers at different latitudes in temperate steppe for three consecutive years from 2012 to 2014. One-way analysis of variance and linear regression were used to analyze the variation in foliar nitrogen (N) and phosphorus (P) contents and the N:P ratio in L. chinensis. The correlations between the foliar N:P ratio and the variation in soil total nitrogen (TN) and total P contents with latitudinal gradient were measured to explore the homeostasis stoichiometry of foliar N and P in L. chinensis. With increasing latitude, both the foliar N and P contents of L. chinensis showed parabolic trends with significant negative correlations. The population of L. chinensis was limited by N, and the soil TN content showed a significant increasing trend with the increase in the foliar N:P ratio. The variation in the foliar N:P ratio of L. chinensis was determined through the variation in the soil N content. In different latitude intervals, the foliar N, P, and N:P ratio of L. chinensis showed absolute stability and strong internal stability, and the values of HN:P were high and similar in different latitudes. In conclusion, the population of L. chinensis in the temperate steppe is highly adaptable; and, thus, can maintain a dominant position in the variable environment and has a wide distribution range. [ABSTRACT FROM AUTHOR]

Microwaves may exert adverse biological effects on the cardiovascular system at the integrated system and cellular levels. However, the mechanism underlying such effects remains poorly understood. Here, we report a previously uncharacterized mechanism through which microwaves damage myocardial cells. Rats were treated with 2450 MHz microwave radiation at 50,100,150, or 200 mW/[cm.sup.2] for 6 min. Microwave treatment significantly enhanced the levels of various enzymes in serum. In addition, it increased the malondialdehyde content while decreasing the levels of antioxidative stress enzymes, activities of enzyme complexes I-IV, and ATP in myocardial tissues. Notably, irradiated myocardial cells exhibited structural damage and underwent apoptosis. Furthermore, Western blot analysis revealed significant changes in expression levels of proteins involved in oxidative stress regulation and apoptotic signaling pathways, indicating that microwave irradiation could induce myocardial cell apoptosis by interfering with oxidative stress and cardiac energy metabolism. Our findings provide useful insights into the mechanism of microwave-induced damage to the cardiovascular system. Key words: microwave radiation, myocardial cell, oxidative stress, energy metabolism. Les micro-ondes pourraient avoir des effets biologiques nefastes sur le systeme cardiovasculaire: dans son integrite comme au niveau cellulaire. Cependant, on connait toujours peu leurs mecanismes sous-jacents. Dans ces travaux, nous rapportons un mecanisme encore jamais caracterise qui mene a des lesions des cellules myocardiques. A cet effet, nous avons administre a des rats des rayonnements de micro-ondes de 2450 MHz a 50,100, 150 ou 200 mW/[cm.sup.2] pendant 6 min, ce qui a entraine une augmentation marquee des taux seriques de divers enzymes. Cette intervention a aussi entraine une augmentation des taux de malondialdehyde ainsi qu'une diminution des taux des enzymes du stress oxydatif, de l'activite des enzymes des complexes I a IV et des taux d'ATP dans le tissu myocardique. Mais surtout, les cellules myocardiques irradiees presentaient des dommages structurels et subissaient l'apoptose. En fait, l'analyse par buvardage de Western a revele la presence de modifications importantes des taux d'expression des proteines jouant un role dans les voies de signalisation de la regulation du stress oxydatif et de l'apoptose, ce qui indique que l'irradiation par les micro-ondes peut induire l'apoptose dans les cellules myocardiques en interferant avec le stress oxydatif et le metabolisme energetique cardiaque. En somme, nos resultats donnent une idee concrete du mecanisme responsable des dommages causes par les micro-ondes au systeme cardiovasculaire. [Traduit par la Redaction] Mots-cles: rayonnement de micro-ondes, cellule myocardique, stress oxydatif, metabolisme energetique., Introduction Microwaves are electromagnetic waves with wavelengths ranging from 1 mm to 1 m and frequencies between 300 MHz and 300 GHz (Gupta 2014; Shahin et al. 2013). Microwave technology [...]

New therapeutic approaches are needed to improve the survival rate from pancreatic cancer, one of the most lethal human malignancies. In this study, JF305 cells were treated with microwaves at doses of 2.5, 5.0,10.0,15.0, and 20.0 mW/[cm.sup.2] for 20 min. The inhibition of JF305 cell proliferation was tested using the MTT assay. Apoptotic cells were detected with Hoechst 33258 staining and a Nucleo-Counter NC-3000. The expression of apoptosis-related proteins was examined with Western blot. The results showed that microwaves inhibited the growth of JF305 cells in a dose-dependent manner, and caused morphological changes in apoptotic body formation. The percentages of apoptosis detected using annexin V-fluorescein isothiocyanate (FITC) were 4.0%, 10.0%, 12.0%, and 30.0% with the dosage of microwave (0, 5.0,10.0, and 20.0 mW/[cm.sup.2]), respectively. Treatment with microwaves increased the activity of caspase-9 and caspase-3, down-regulated the expression of Bcl-2, and up-regulated the expression of Bax and CytoC. In addition, the expression level of p65 was increased whereas the level of IκBα down-regulated. Those results suggest that microwaves inhibit cell growth and induce apoptosis in JF305 cells through an NF-κB-regulated mitochondria-mediated pathway. Key words: anticancer, microwave, JF305 cells, apoptosis. De nouvelles approches therapeutiques sont requises afin d'ameliorer le taux de survie des patients atteints du cancer du pancreas, un des cancers les plus letaux chez l'humain. Dans cette etude, les cellules JF305 ont ete traitees par des microondes a des doses de 2,5, 5,0, 10,0, 15,0 et 20,0 mW/[cm.sup.2] pendant 20 minutes. L'inhibition de la proliferation des cellules JF305 a ete testee a l'aide d'un dosage au MTT. Les cellules en apoptose ont ete detectees par une coloration au Hoechst 33258 sur un Nucleo-Counter NC-3000. L'expression de proteines reliees a l'apoptose a ete examinee par buvardage Western. Les resultats ont montre que les microondes peuvent inhiber la croissance des cellules JF305 en fonction de la dose et causer des changements morphologiques dans la formation de corps apoptotiques. Les pourcentages de cellules en apoptose detectes par l'Annexine V-FITC etaient respectivement de 4,0, 10,0, 12,0 et 30,0 % en fonction de la dose de microondes (0, 5,0, 10,0, et 20,0 mW/[cm.sup.2]). Le traitement aux microondes accroissait l'activite de la caspase-9 et de la caspase-3, regulait a la baisse l'expression de Bcl-2 et regulait a la hausse l'expression de Bax et CytoC. En plus, le niveau d'expression de p65 etait accru alors que celui de IκBα etait diminue. Ces resultats suggerent que les microondes inhibent la croissance cellulaire et induisent l'apoptose des cellules JF305 par l'intermediaire d'une voie mitochondriale regulee par NF-κB. [Traduit par la Redaction] Mots-cles: anti-cancer, microonde, cellules JF305, apoptose., Introduction Pancreatic cancer is one of the most lethal human malignancies, with a mortality rate of up to 96%. Pancreatic adenocarcinoma is locally invasive and is surrounded by a dense [...]

Leymus chinensis is a primary plant in the meadow steppe and typical steppe of China. With global warming and increasing grazing intensity, grassland degradation is being exacerbated. To better protect the L. chinensis grassland in this area and provide a theoretical basis for restoring it, this paper compared the germinable seed bank in the soil and the germination characteristics of L. chinensis (including initial germination time, duration of germination, germination termination time, germination dynamics, and germination index) in free-grazing and enclosed areas. At the same time, combining information about the density of L. chinensis on the ground and previous research results, a comprehensive analysis was conducted. The major results were: (1) there was no significant difference in the number of germinable seeds in the soil between the free-grazing area and the enclosed area, and these seeds were mainly concentrated in the 0–2 cm soil layer. (2) The free-grazing area resulted in a significant increase in the number of germinable L. chinensis seeds and advanced the initial germination time. (3) The number of soil germinated seeds and the number of L. chinensis germinated seeds decreased with the increase in soil depth. (4) Livestock grazing behaviours increased seed burial, thus improving the L. chinensis germination rate. At the same time, the L. chinensis seed bearing percentage and seed quality and the number of germinable L. chinensis seeds were significantly higher in the free-grazing area than in the enclosed area. However, this result still needs to be further explored. [ABSTRACT FROM AUTHOR]

Induction of apoptosis in tumor cells has become the major focus of anti-tumor therapeutics development. Juglone, a major chemical constituent of Juglans mandshurica Maxim, possesses several bioactivities, including anti-tumor. In the present study, HeLa cells were incubated with juglone at various concentrations. The proliferation inhibition of juglone on HeLa cells was tested by the MTT assay. Occurrence of apoptosis was detected by Hoechst 33258 staining, flow cytometry, and transmission electron microscopy. The expression of apoptotic-related proteins was examined by Western blot. The results showed that juglone inhibits the growth of HeLa cells in dose--dependent manner. Topical morphological changes of apoptotic body formation after juglone treatment were observed. The percentages of early apoptosis of Annexin V-FITC were 5.23%, 7.95%, 10.69%, and 20.92% with the concentrations of juglone (12.5, 25, 50, and 100 (µmol/L), respectively. After cells were treated with juglone at the different dose for 24 h, the expression of Bcl-2 was significantly down-regulated and the expression of Bax was significantly up-regulated compared with the control. These events paralleled with activation of caspase-9, -8, -3, and PARP cleavage. The results suggest that juglone may be effective for the treatment of HeLa cells. Key words: anticancer, juglone, HeLa cells, apoptosis, cytotoxicity, caspases, early apoptosis. L'induction de l'apoptose des cellules tumorales est devenu un element central du developpement de therapies anti-tumorales. La juglone, la constituante chimique principale de Juglans mandshurica Maxim, possede plusieurs activites biologiques dont une activite anti-tumorale. Dans cette etude, des cellules HeLa ont ete incubees avec differentes concentrations de juglone. L'inhibition de la proliferation des cellules HeLa par la juglone a ete mesuree par le dosage de MTT. L'apoptose a ete detectee par une coloration au Hoechst 33258, par cytometrie de flux et par microscopie electronique a transmission. L'expression de proteines reliees a l'apoptose a ete examinee par buvardage Western. Les resultats ont montre que la juglone inhibe la croissance des cellules HeLa de facon dependante de la concentration. Des changements morphologiques locaux dans la formation de corps apoptotiques a la suite du traitement a la juglone ont ete observes. Les pourcentages d'apoptose precoce detectes par la coloration a l'annexine V-FITC etaient de 5,23 %, 7,95 %, 10,69 % et 20,92 % a des concentrations de 12,5 , 25 , 50 et 100 (µmol/L de juglone, respectivement. Apres que les cellules aient ete traitees aux differentes concentrations de juglone pendant 24 h, l'expression de Bcl-2 etait significativement diminuee et l'expression de Bax etait significativement regulee a la hausse comparativement aux controles. Ces evenements se deroulaient parallelement a l'activation des capsases 9, 8 et 3 ainsi qu'au clivage de la PARP. Ces resultats suggerent que la juglone peut etre efficace dans le traitement des cellules HeLa. Mots-cles : anti-cancer, juglone, cellules HeLa, apoptose, cytotoxicite, caspases, apoptose precoce. [Traduit par la Redaction], Introduction Human cervical cancer is a major mortality factor in the female population. HeLa cell (also Hela or hela cell) is a cell type in an immortal cell line used [...]