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1.
The objective of this study was to determine the occurrence and distribution of antibiotic resistant (AR) lactic acid bacteria (LAB) in Indian poultry. LAB from poultry farm feces (n = 21) and samples from slaughter houses comprising chicken intestine (n = 46), raw meat (n = 23), and sanitary water (n = 4) were evaluated and compared with those from organic chicken (OC) collected from nearby villages. Screening studies showed 5–7 log units higher erythromycin (ER), tetracycline (TC) and vancomycin (VAN) resistant LAB from conventional poultry chicken (CC) compared to OC. Molecular characterization of isolated cultures (n = 32) with repetitive-PCR profiling and 16S rRNA gene sequencing revealed their taxonomical status as Enterococcus faecium (n = 16), Enterococcus durans (n = 2), Lactobacillus plantarum (n = 10), Lactobacillus pentosus (n = 1) and Lactobacillus salivarius (n = 3). The isolates were found to harbor erm(B), msr(C), msr(A/B), tet(M), tet(L) and tet(K) genes associated with Tn916 and Tn917 family transposons. Expression studies through real-time PCR revealed antibiotic-induced expression of the identified AR genes. In vitro and in vivo conjugational studies revealed transfer of ER and TC resistant (ERR and TCR) genes with transfer frequencies of 10?7 and 10?4 transconjugants recipient?1, respectively. Although no known VAN resistance (VANR) genes were detected, high phenotypic resistance was observed and was transferable to the recipient. From a public health point of view, this study reports Indian poultry as a major source of high levels of AR bacteria contaminating the food chain and the environment. Thus, urgent and determined strategies are needed to control the spread of multiple AR bacteria.  相似文献   

2.
Bombacoideae is one out of nine subfamilies of Malvaceae and encompasses 160 tree species. The subfamily is karyotypically characterized by small and numerous chromosomes and is traditionally known by a remarkable inter- and intraspecific chromosome number variation. We conducted a comparative cytogenetic analysis to investigate karyotype diversity and chromosome evolution within Bombacoideae. To achieve this, we performed new chromosome counts, CMA/DAPI double staining, genome size estimations, and localization of 5S and 45S rDNA by fluorescence in situ hybridization for 21 species distributed across the Bombacoideae phylogeny. We performed ancestral states reconstruction analyses to elucidate chromosome evolution and provide insights into the systematics and evolution of Bombacoideae in comparison with other Malvaceae species. Newly generated data on chromosome number on Bombacoideae revealed diploids (Ochroma (2n = 84), Cavanillesia, Pochota, Pseudobombax (2n = 88), and Pachira (2n = 92)) and polyploids (Adansonia digitata (2n = 160) and Eriotheca species (2n = ca. 194 and 2n = 276)). For most species, in situ hybridization revealed karyotype, with two pairs of 45S rDNA sites co-located with CMA+ bands, and 5S rDNA sites in only one chromosome pair. Taken together, our results provide support to the hypothesis of karyotypic stability in Bombacoideae. Only the Pachira s.l. clade displayed some variability in ploidy level, number of CMA+ bands and 45S rDNA sites, and genome size compared to other Bombacoideae clades. The Striated bark clade was characterized by comparatively small genomes and low cytomolecular variability. Karyotypic data were related to biogeographic and species richness patterns of Bombacoideae.  相似文献   

3.
Ontogenetic niche theory predicts that individuals may undergo one or more changes in habitat or diet throughout their lifetime to maintain optimal growth rates, or to optimize trade-offs between mortality risk and growth. We combine skeletochronological and stable nitrogen isotope (δ15N) analyses of sea turtle humeri (n = 61) to characterize the growth dynamics of juvenile loggerhead sea turtles (Caretta caretta) during an oceanic-to-neritic ontogenetic shift. The primary objective of this study was to determine how ontogenetic niche theory extends to sea turtles, and to individuals with different patterns of resource use (discrete shifters, n = 23; facultative shifters n = 14; non-shifters, n = 24). Mean growth rates peaked at the start of the ontogenetic shift (based on change in δ15N values), but returned to pre-shift levels within 2 years. Turtles generally only experienced 1 year of relatively high growth, but the timing of peak growth relative to the start of an ontogenetic shift varied among individuals (before, n = 14; during, n = 12; after, n = 8). Furthermore, no reduction in growth preceded the transition, as is predicted by ontogenetic niche theory. Annual growth rates were similar between non-transitioning turtles resident in oceanic and neritic habitats and turtles displaying alternative patterns of resource use. These results suggest that factors other than maximization of size-specific growth may more strongly influence the timing of ontogenetic shifts in loggerhead sea turtles, and that alternative patterns of resource use may have limited influence on somatic growth and age at maturation in this species.  相似文献   

4.
5.
The concentration of cadmium in human tissues obtained on the basis of autopsies of non-poisoned Polish people (n = 150), aged from 1 to 80 years, examined between 1990 and 2010, is presented. The following values were found in wet digested samples by flame atomic absorption spectrometry (FAAS) (mean ± SD, median, and range, μg/g of wet weight): brain 0.020 ± 0.031, 0.084, 0–0.120 (n = 41); stomach 0.148 ± 0.195, 0.084, 0–1.25 (n = 89); small intestine 0.227 ± 0.231, 0.130, 0–0.830 (n = 39); liver 1.54 ± 1.55, 1.01, 0.015–9.65 (n = 99); kidney 16.0 ± 13.2, 14.0, 0.62–61.3 (n = 91); lung 0.304 ± 0.414, 0.130, 0–1.90 (n = 25); and heart 0.137 ± 0.107, 0.140, 0.017–0.250 (n = 4). Additionally, results (n = 13 people, aged from 2 to 83 years, 63 samples) obtained by inductively coupled plasma optical emission spectrometry (ICP OES) between 2010 and 2015 are given. The obtained data on Cd concentration in the human body can be used to estimate the amounts occurring in “healthy” people and those occurring in cases of chronic or acute poisonings with Cd compounds, which are examined for forensic purposes or to assess environmental exposure levels.  相似文献   

6.
We aim to investigate whether overweight/obese pregnant women have elevated plasma levels of adenosine associated with increased consumption of high-calorie food. Sixty women were included. They were divided into lean (n = 23 and n = 12) or overweight/obese (n = 7 and n = 18) non-pregnant and pregnant women, respectively. Clinical records and maternal blood samples were collected after informed consent. A self-reported dietary questionnaire was also completed. Plasma adenosine levels were determined with high-performance liquid chromatography. Biochemical parameters, including glucose, total protein, and lipid profile, were determined using standard colorimetric assays. Adenosine levels were higher in pregnant women than in non-pregnant women (18.7 ± 1.6 vs 10.8 ± 1.3 nM/μg protein, respectively, p < 0.0001). Overweight/obese pregnant women (21.9 ± 2.5 nM/μg protein) exhibited higher adenosine levels than lean pregnant (14.5 ± 1.0 nM/μg protein, p = 0.04) or non-pregnant women (11.7 ± 1.5 nM/μg protein, p = 0.0005). Also, pregnant women with elevated weight gain exhibited higher (26.2 ± 3.7 nM/μg protein) adenosine levels than those with adequate weight gain (14.9 ± 1.4 nM/μg protein, p = 0.03). These differences were not statistically significant compared with those of pregnant women with reduced weight gain (17.4 ± 2.1 nM/μg protein, p = 0.053). Body mass index and adenosine only in pregnant women were positively correlated (r = 0.39, p = 0.02). While, polyunsaturated fatty acid (PUFA) consumption was negatively correlated with plasma adenosine levels only in non-pregnant women (r = ?0.33, p = 0.03). Pregnancy is associated with high plasma adenosine levels, which are further elevated in pregnant women who are overweight/obese. High PUFA intake might reduce plasma adenosine levels in non-pregnant women.  相似文献   

7.
Fundulus grandis (Baird and Girard), the Gulf Killifish, is an abundant species throughout the marshes of the northern Gulf of Mexico. Its wide distribution and high site fidelity makes it an ideal indicator species for brackish and salt marshes, which experience a variety of anthropogenic disturbances. Despite the ecological, commercial, and scientific importance of F. grandis, age determination methods have not been validated and little is known of its growth pattern. By combining a tag-recapture study with a chemical marker to stain otoliths, we validated an ageing method for F. grandis adults (49–128 mm TL) using whole sagittal otoliths and determined growth rates of recaptured individuals in winter (n = 58) and summer (n = 36) in Louisiana. Mean somatic growth in length was significantly greater during the winter (0.085 mm d?1) than summer (0.054 mm d?1). In contrast, mean otolith growth was significantly greater in summer (1.37 μm d?1) than winter (0.826 μm d?1). The uncoupling of somatic and otolith growth may be primarily attributed to warm summer temperatures, which led to enhanced otolith growth while simultaneously reducing somatic growth. Fundulus grandis was aged to a maximum of 2.25 years. The parameters of the von Bertalanffy growth model were estimated as: L  = 87.27 mm, k = 2.43 year?1, and t 0 = ?0.022. These findings reveal essential age and growth information for F. grandis and provide a benchmark to evaluate responses to environmental disturbances.  相似文献   

8.
This study was conducted to evaluate the effects of selenium supplementation on gene expression related to insulin and lipid in infertile women with polycystic ovary syndrome (PCOS) candidate for in vitro fertilization (IVF). This randomized double-blind, placebo-controlled trial was conducted among 40 infertile women with PCOS candidate for IVF. Subjects were randomly allocated into two groups to intake either 200-μg selenium (n = 20) or placebo (n = 20) per day for 8 weeks. Gene expression levels related to insulin and lipid were quantified in lymphocytes of women with PCOS candidate for IVF with RT-PCR method. Results of RT-PCR demonstrated that after the 8-week intervention, compared with the placebo, selenium supplementation upregulated gene expression of peroxisome proliferator-activated receptor gamma (PPAR-γ) (1.06 ± 0.15-fold increase vs. 0.94 ± 0.18-fold reduction, P = 0.02) and glucose transporter 1 (GLUT-1) (1.07 ± 0.20-fold increase vs. 0.87 ± 0.18-fold reduction, P = 0.003) in lymphocytes of women with PCOS candidate for IVF. In addition, compared with the placebo, selenium supplementation downregulated gene expression of low-density lipoprotein receptor (LDLR) (0.88 ± 0.17-fold reduction vs. 1.05 ± 0.22-fold increase, P = 0.01) in lymphocytes of women with PCOS candidate for IVF. We did not observe any significant effect of selenium supplementation on gene expression levels of lipoprotein(a) [LP(a)] in lymphocytes of women with PCOS candidate for IVF. Overall, selenium supplementation for 8 weeks in lymphocytes of women with infertile PCOS candidate for IVF significantly increased gene expression levels of PPAR-γ and GLUT-1 and significantly decreased gene expression levels of LDLR, but did not affect LP(a).Clinical trial registration number: http://www.irct.ir: IRCT201704245623N113.  相似文献   

9.
Satellite DNA repeats (or satDNA) are fast-evolving sequences usually associated with condensed heterochromatin. To test whether the chromosomal organisation of centromeric and non-centromeric satDNA differs in species with holocentric chromosomes, we identified and characterised the major satDNA families in the holocentric Cyperaceae species Rhynchospora ciliata (2n = 10), R. globosa (2n = 50) and R. tenuis (2n = 2x = 4 and 2n = 4x = 8). While conserved centromeric repeats (present in R. ciliata and R. tenuis) revealed linear signals at both chromatids, non-centromeric, species-specific satDNAs formed distinct clusters along the chromosomes. Colocalisation of both repeat types resulted in a ladder-like hybridisation pattern at mitotic chromosomes. In interphase, the centromeric satDNA was dispersed while non-centromeric satDNA clustered and partly colocalised to chromocentres. Despite the banding-like hybridisation patterns of the clustered satDNA, the identification of chromosome pairs was impaired due to the irregular hybridisation patterns of the homologues in R. tenuis and R. ciliata. These differences are probably caused by restricted or impaired meiotic recombination as reported for R. tenuis, or alternatively by complex chromosome rearrangements or unequal condensation of homologous metaphase chromosomes. Thus, holocentricity influences the chromosomal organisation leading to differences in the distribution patterns and condensation dynamics of centromeric and non-centromeric satDNA.  相似文献   

10.
Trypanosomiasis is a neglected tropical disease of both livestock and humans. Although pastoral communities of the Maasai Steppe have been able to adapt to trypanosomiasis in the past, their traditional strategies are now constrained by changes in climate and land regimes that affect their ability to move with their herds and continually shape the communities’ vulnerability to trypanosomiasis. Despite these constraints, information on communities’ vulnerability and adaptive capacity to trypanosomiasis is limited. A cross-sectional study was therefore conducted in Simanjiro and Monduli districts of the Maasai Steppe to establish pastoralists’ vulnerability to animal trypanosomiasis and factors that determined their adaptation strategies. A weighted overlay approach in ArcGIS 10.4 was used to analyze vulnerability levels while binomial and multinomial logistic regressions in R 3.3.2 were used to analyze the determinants of adaptation. Simanjiro district was the most vulnerable to trypanosomiasis. The majority (87.5%, n = 136) of the respondents were aware of trypanosomiasis in animals, but only 7.4% (n = 136) knew about the human form of the disease. Reported impacts of animal trypanosomiasis were low milk production (95.6%, n = 136), death of livestock (96.8%, n = 136) and emaciation of animals (99.9%, n = 136). Crop farming was the most frequently reported animal trypanosomiasis adaptation strategy (66%, n = 136). At a 95% confidence interval, accessibility to livestock extension services (β = 7.61, SE = 3.28, df = 135, P = 0.02), years of livestock keeping experience (β = 6.17, SE = 1.95, df = 135, P = 0.001), number of cattle owned (β = 5.85, SE = 2.70, df = 135, P = 0.03) and membership in associations (β = ? 4.11, SE = 1.79, df = 135, P = 0.02) had a significant impact on the probability of adapting to animal trypanosomiasis.  相似文献   

11.
Triticum timopheevii (2n = 4x = 28, GGAtAt) is a tetraploid wheat formerly cultivated in western Georgia. The natural allopolyploid Triticum zhukovskyi is a hexaploid taxon originated from hybridization of T. timopheevii with cultivated einkorn T. monococcum (2n = 2x = 14, AmAm). Karyotypically T. timopheevii and T. zhukovskyi differ from other tetraploid and hexaploid wheats and were assigned to the section Timopheevii of the genus Triticum L. Triticum timopheevii and T. zhukovskyi are resistant to many fungal diseases and therefore could potentially be utilized for wheat improvement. We were aiming to precisely identify all T. timopheevii chromosomes and to trace the evolution of T. zhukovskyi. For this, we developed a set of molecular cytogenetic landmarks based on eleven DNA probes. Each chromosome can now be characterized by two to eight probes. The pTa-535 sequence allows the identification of all At-genome chromosomes, whereas G-genome and some At-genome chromosomes can be identified using (GAA/CTT) n and pSc119.2 probes. The probes pAesp_SAT86, pAs1, Spelt-1, Spelt-52 and 5S and 45S rDNA can be applied as additional markers to discriminate particular chromosomes or chromosomal regions. The distribution of (GAA/CTT) n , pTa-535 and pSc119.2 DNA probes on T. timopheevii chromosomes is distinct from other tetraploid wheats and can therefore be used to track individual chromosomes in introgression programs. Our study confirms the origin of T. zhukovskyi from hybridization of T. timopheevii with T. monococcum; however, we show that the emergence was accompanied by changes involving mostly At-genome chromosomes. This may be due to the presence of two closely related A-genomes in the T. zhukovskyi karyotype.  相似文献   

12.
The aims of the present study were to develop a parameterization of a one-year-long observed PAR time-series, apply the PAR parameterization in a primary production relation, and compare calculated and observed time-series of primary production. The PAR parameterization was applied in the generally used relation for the primary production (P d): P d = a(BI 0 Z 0) + b with observed photic depth (Z 0) and Chl-a concentrations (B). It was tested whether the PAR parameterization in combination with this simple relation for primary production was able to describe the actual measured primary production. The study is based on a one year long time-series of PAR, CTD-casts (n = 45), and primary production measurements (n = 24) from Århus Bay (56°09′ N; 10°20′ E), south west Kattegat. Results showed a high and positive correlation between observed and calculated primary production in the bay, as based on the present PAR parameterization combined with the simple primary production relation. The developed PAR parameterization, which calculates total daily surface irradiance per day (M photons m?2 d?1), can be applied in any ecological application taking into account that it was developed for the latitude of 56° N.  相似文献   

13.
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease with strong genetic components. To identity novel risk variants for ALS, utilizing the latest genome-wide association studies (GWAS) and eQTL study data, we conducted a genome-wide expression association analysis by summary data-based Mendelian randomization (SMR) method. Summary data were derived from a large-scale GWAS of ALS, involving 12577 cases and 23475 controls. The eQTL annotation dataset included 923,021 cis-eQTL for 14,329 genes and 4732 trans-eQTL for 2612 genes. Genome-wide single gene expression association analysis was conducted by SMR software. To identify ALS-associated biological pathways, the SMR analysis results were further subjected to gene set enrichment analysis (GSEA). SMR single gene analysis identified one significant and four suggestive genes associated with ALS, including C9ORF72 (P value = 7.08 × 10?6), NT5C3L (P value = 1.33 × 10?5), GGNBP2 (P value = 1.81 × 10?5), ZNHIT3(P value = 2.94 × 10?5), and KIAA1600(P value = 9.97 × 10?5). GSEA identified 7 significant biological pathways, such as PEROXISOME (empirical P value = 0.006), GLYCOLYSIS_GLUCONEOGENESIS (empirical P value = 0.043), and ARACHIDONIC_ACID_ METABOLISM (empirical P value = 0.040). Our study provides novel clues for the genetic mechanism studies of ALS.  相似文献   

14.
Odonata have been widely used as indicators for the biomonitoring of terrestrial and aquatic habitats due to their sensitivity to environmental impacts. We aimed to determine whether the larval or adult phases of these insects were the best predictors of variation in habitat parameters and the loss of environmental integrity. Specimens were collected during three seasons (dry, rainy, and ebb) from 12 points in the Suiá-missu River basin, at the headwaters of the Xingu River in Mato Grosso, Brazil. The Protest analysis indicated a high degree of congruence between the assemblages of larvae and adults in streams with varying degrees of habitat integrity (R = 0.832, p < 0.001, m 2 = 0.307). When the congruence with environmental factors was analyzed, a significant association was found only for the larval phase (R = 0.318, p = 0.03, m 2 = 0.888). When the suborders were analyzed separately, congruence was confirmed for anisopteran adults (R = 0.338, p = 0.031, m 2 = 0.885) and larvae (R = 0.417, p = 0.003, m 2 = 0.826) and for the zygopteran adults (R = 0.345, p = 0.027, m 2 = 0.881) and larvae (R = 0.405, p = 0.011, m 2 = 0.836). These results indicate that both larvae and adults respond systematically to environmental impacts. We suggest that either life phase can be used for biomonitoring, given their effectiveness for the interpretation of disturbance in terrestrial and aquatic habitats. These findings further reinforce the effectiveness of this insect order for the detection of modifications to the environment, showing that they are good indicators of environmental conditions.  相似文献   

15.
The annual routines and seasonal ecology of herbivorous zooplankton species are relatively well known due to their tight coupling with their pulsed food source, the primary production. For higher trophic levels of plankton, these seasonal interactions are less well understood. Here, we study the mid-winter feeding of chaetognaths in high-Arctic fjord ecosystems. Chaetognaths are planktivorous predators which comprise high biomass in high-latitude seas. We investigated the common species Parasagitta elegans around the Svalbard archipelago (78–81°N) during the winters of 2012 and 2013. Our samples consisted of individuals (body lengths 9–55 mm) from three fjords, which were examined for gut contents (n = 903), stable isotopes, fatty acid composition, and maturity status (n = 352). About a quarter of the individuals contained gut contents, mainly lipid droplets and chitinous debris, whilst only 4 % contained identifiable prey, chiefly the copepods Calanus spp. and Metridia longa. The δ15N content of P. elegans, and its average trophic level of 2.9, confirmed its carnivorous position and its fatty acid profile [in particular its high levels of 20:1(n-9) and 22:1(n-11)] confirmed carnivory on Calanus. Observations of undeveloped gonads in many of the larger P. elegans, and the absence of small individuals <10 mm, suggested that reproduction had not started this early in the year. Its average feeding rate across fjords and years was 0.12 prey ind.?1 day?1, which is low compared to estimates of spring and summer feeding in high-latitude environments. Our findings suggest reduced feeding activity during winter and that predation by P. elegans had little impact on the mortality of copepods.  相似文献   

16.
Data on the effects of selenium supplementation on clinical signs and metabolic profiles in women at risk for intrauterine growth restriction (IUGR) are scarce. This study was designed to assess the effects of selenium supplementation on clinical signs and metabolic status in pregnant women at risk for IUGR. This randomized double-blind placebo-controlled clinical trial was performed among 60 women at risk for IUGR according to abnormal uterine artery Doppler waveform. Participants were randomly assigned to intake either 100 μg selenium supplements as tablet (n = 30) or placebo (n = 30) for 10 weeks between 17 and 27 weeks of gestation. After 10 weeks of selenium administration, a higher percentage of women in the selenium group had pulsatility index (PI) of <1.45) (P = 0.002) than of those in the placebo group. In addition, changes in plasma levels of total antioxidant capacity (TAC) (P < 0.001), glutathione (GSH) (P = 0.008), and high-sensitivity C-reactive protein (hs-CRP) (P = 0.004) in the selenium group were significant compared with the placebo group. Additionally, selenium supplementation significantly decreased serum insulin (P = 0.02), homeostasis model of assessment-estimated insulin resistance (HOMA-IR) (P = 0.02), and homeostatic model assessment for B-cell function (HOMA-B) (P = 0.02) and significantly increased quantitative insulin sensitivity check index (QUICKI) (P = 0.04) and HDL-C levels (P = 0.02) compared with the placebo. We did not find any significant effect of selenium administration on malondialdehyde (MDA), nitric oxide (NO), fasting plasma glucose (FPG), and other lipid profiles. Overall, selenium supplementation in pregnant women at risk for IUGR resulted in improved PI, TAC, GSH, hs-CRP, and markers of insulin metabolism and HDL-C levels, but it did not affect MDA, NO, FPG, and other lipid profiles.Clinical trial registration number http://www.irct.ir: IRCT201601045623N64.  相似文献   

17.
Behavior of adult Parahucho perryi was examined using bio-logging and acoustic telemetry concurrently in the Bekanbeushi River system, eastern Hokkaido, Japan, in 2009 and 2010. Based on 46.1–87.9 h data from five P. perryi (69.0–80.0 cm fork length) caught from Lake Akkeshi, they used upstream (n = 2), midstream (n = 3), and downstream (n = 4) habitats. Large variability in diel activity and depth occupation existed in each stream habitat; however, fish in the downstream habitat tended to be more active than those in the upper habitats and mainly occupied shallower depths than mean bottom depth in this habitat.  相似文献   

18.
The present study aims to examine the changes in the serum levels of trace elements before and after the operation in thyroid cancer patients. The study registered 50 individuals, of whom 25 were female and 25 were male. The patients were allocated to four groups: group 1: male thyroid cancer patients group (n = 15), group 2: female thyroid cancer patients group (n = 15), group 3: male control group (n = 10), group 4: female control group (n = 10). The subjects in groups 1 and 2 were the patients who were post-operatively diagnosed with a pathological malignancy in the thyroid tissue samples. Blood samples were collected from all subjects before the operation, immediately after the operation, and on the post-operative day 15. Additionally, thyroid tissue samples were taken from all subjects post-operatively. Some elements in the blood and tissue samples were determined using the atomic emission method. Zinc and selenium levels of groups 1 and 2 in the pre- and post-operative measurements were significantly lower than those in the control groups (p < 0.05), but were higher in the thyroid tissue (p < 0.05). Serum zinc and selenium levels measured in the subjects on the post-operative day 15 were similar to those measured in the controls. Our study show that changes in the serum and thyroid tissue levels of trace elements like zinc and selenium, which play a critical role in thyroid function, might be associated with the pathogenesis of thyroid cancer.  相似文献   

19.

Key message

This article provides significant data in the debate on whether siltation might have a negative impact on the hydraulic functioning of two widespread mangrove tree species Avicennia marina and Rhizophora mucronata.

Abstract

Elevated sediment addition, or siltation, within mangrove ecosystems is considered as being negative for trees and saplings, resulting in stress and higher mortality rates. However, little is known about how siltation influences the hydraulic functioning of mangrove trees. Comparing two mangrove tree species (Avicennia marina Vierh. Forsk. and Rhizophora mucronata Lam.) from low and high-siltation plots led to the detection of anatomical and morphological differences and tendencies. Adaptations to high siltation were found to be either mutual among both species, e.g., significant smaller single leaf area (p A.marina  = 0.058, F1.38 = 3.8; p R.mucronata  = 0.005, F1.38 = 8.7; n = 20 × 20) and a tendency towards smaller stomatal areas (p A.marina  = 0.131, F1.8 = 2.8; p R.mucronata  = 0.185, F1.8 = 2.1, n = 5 × 60), or species-specific trends for A. marina, such as higher phloem band/growth layer ratios (p = 0.101, F1.8 = 3.4, n = 5 × 3) and stomatal density (p = 0.052, F1.8 = 5.2, n = 5 × 4). All adaptations seemingly contributed to a comparable hydraulic conductivity independent of the degree of siltation. These findings indicate that silted trees level off fluctuations in their hydraulic performance as a survival mechanism to cope with this less favourable environment. Most of the trees’ structural adaptations to cope with siltation are similar to known drought stress-imposed adaptations.
  相似文献   

20.
Calcium channel antagonists are commonly used to treat neuropathic pain. Their analgesic effects rely on inhibiting long-term potentiation, and neurotransmitters release in the spinal cord. Store-operated Ca2+channels (SOCCs) are highly Ca2+-selective cation channels broadly expressed in non-excitable cells and some excitable cells. Recent studies have shown that the potent inhibitor of SOCCs, YM-58483, has analgesic effects on neuropathic pain, but its mechanism is unclear. This experiment performed on spinal nerve ligation (SNL)-induced neuropathic pain model in rats tries to explore the mechanism, whereby YM-58483 attenuates neuropathic pain. The left L5 was ligated to produce the SNL neuropathic pain model in male Sprague–Dawley rats. The withdrawal threshold of rats was measured by the up–down method and Hargreaves’ method before and after intrathecal administration of YM-58483 and vehicle. The SOCCs in the spinal dorsal horn were located by immunofluorescence. The expression of phosphorylated ERK and phosphorylated CREB, CD11b, and GFAP proteins in spinal level was tested by Western blot, while the release of proinflammatory cytokines (IL-1β, TNF-α, PGE2) was measured by enzyme-linked immunosorbent assay (ELISA). Intrathecal YM-58483 at the concentration of 300 μM (1.5 nmol) and 1000 μM (10 nmol) produced a significant central analgesic effect on the SNL rats, compared with control + vehicle (n = 7, P < 0.001). However, both could not prevent the development of neuropathic pain, compared with normal + saline (P < 0.001). Immunofluorescent staining revealed that Orai1 and STIM1 (the two key components of SOCCs) were located in the spinal dorsal horn neurons. Western blot showed that YM-58483 could decrease the levels of P-ERK and P-CREB (n = 10, #P < 0.05), without affecting the expression of CD11b and GFAP (n = 10, #P > 0.05). YM-58483 also inhibited the release of spinal cord IL-1β, TNF-α, and PGE2, compared with control + vehicle (n = 5, #P < 0.001). The analgesic mechanism of YM-58483 may be via inhibiting central ERK/CREB signaling in the neurons and decreasing central IL-1β, TNF-α, and PGE2 release to reduce neuronal excitability in the spinal dorsal horn of the SNL rats.  相似文献   

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