ABSTRACT
Fungi represent key ecosystem factors that affect plant growth and development and improve soil structure and fertility. Due to changes in environmental conditions, fungi show strong spatial heterogeneity along altitudinal gradients. Current knowledge of the driving mechanisms and effects of soil fungal community construction at high altitudes is very limited on a regional scale. We collected soil samples from alpine grasslands at six altitudinal gradients (2813-5228 m) in the high-altitude area of the Qinghai-Tibet Plateau. The horizontal distance of the sampling zone spanned 1500 km. Distribution patterns, key influencing factors for soil fungal diversity, and dominant mechanisms of ecological processes in the alpine grasslands were analyzed. We found that the diversity of the soil fungal communities was significantly different at different altitudes; with increasing altitude, the number of fungal species increased. Mucoromycota was better adapted to alpine grassland ecosystems at altitudes of above 4000 m. Dispersal limitation was the main ecological control process among stochastic processes. With the increase of altitude, the dominant role of dispersal limitation gradually decreased, and the proportion of other random processes such as ecological drift gradually increased. In this study, soil geochemical factors (soil organic carbon, SOC; total phosphorus, TP) mainly influenced the composition of the fungal community in the low altitude region, while climatic factors (mean annual temperature, MAT) were the key factors and main driving forces for the composition of the soil fungal community in the alpine meadow in the high altitude region. This study supplements the information on the biogeographic distribution patterns and environmental drivers of fungal communities along altitudinal gradients at high altitudes on a regional scale. Our results highlight the effects of temperature change on fungal community composition in high altitude regions of alpine grasslands. Subsurface fungal communities should be considered when predicting the function of alpine grassland ecosystems under future climate change.
Subject(s)
Ecosystem , Mycobiome , Grassland , Biodiversity , Altitude , Soil/chemistry , Carbon , Tibet , Soil MicrobiologyABSTRACT
Shrubs are the major components of vegetation in arid and semi-arid areas, and play a pivotal role in maintaining ecosystem stability and function. The nurse effects of shrubs can help with the regeneration of native target plant species by alleviating the adverse influences that limit their growth and reproduction in degraded habitats. We summarized the main research results and application of shrub nurse effects in the last 20 years. We discussed several facilitation mechanisms of nurse shrubs, including microhabitat amelioration, fertile island formation, defense and resistance against herbivores, introduction of beneficial microorganism and propagule propagation or preservation, as well as changes in the patterns of interspecific competitive networks. Key factors affecting nurse effects were analyzed, including abiotic environments, biological disturbances, plant life history as well as growth and reproductive strategies. Prospects for future research were also considered from the aspects of improving theore-tical mechanisms of nurse effects by shrubs and building models involved in multiple plant species interaction affec-ted by multifactors.
Subject(s)
Ecosystem , Plants , HerbivoryABSTRACT
To investigate the differences of soil carbon, nitrogen, and carbon stable isotopes in Zoige wetland, we analyzed the abundance of carbon stable isotopes and the contents of carbon and nitrogen in soils of three kinds of retrogressive successional grasslands (swampy meadow, steppe meadow, and degraded meadow). The results showed that the δ13C values in the meadow soil of Zoige alpine wetland ranged from -26.21 to -24.72. The abundance of δ13C increased with the depth of soil. There was a significantly negative relationship between δ13C values and logarithm of soil organic carbon content across the soil profile. The δ13C values in the surface soil (0-10 cm) followed the order of grassland meadow>degraded meadow>swampy meadow, and the ß values followed the order of grassland meadow>swampy meadow>degraded meadow. Soil organic carbon content was 105.32, 42.11 and 31.12 g·kg-1, while nitrogen content was 8.74, 3.41 and 2.81 g·kg-1, and C/N was 11.26, 11.23 and 10.89, in the swampy meadow, grassland meadow and degraded meadow, respectively. The soil C/N was lower in degraded meadow than that in swampy meadow and grassland meadow. The total organic carbon and nitrogen content decreased obviously with increasing soil depth. The variations of soil δ13C among meadows with different degradation stages were mainly restricted to the 0-10 cm soil layer. The ß values and C/N were the lowest in degraded meadow among three stages, suggesting that the mineralization rate of degraded meadow soil organic matter was relatively fast.
Subject(s)
Carbon Isotopes/analysis , Carbon/analysis , Nitrogen/analysis , Wetlands , Grassland , Soil , Soil MicrobiologyABSTRACT
Water quality detection plays an increasingly important role in environmental protection. In this work, a novel colorimeter based on the Beer-Lambert law was designed for chemical element detection in water with high precision and miniaturized structure. As an example, the colorimeter can detect phosphorus, which was accomplished in this article to evaluate the performance. Simultaneously, a modified algorithm was applied to extend the linear measurable range. The colorimeter encompassed a near infrared laser source, a microflow cell based on microfluidic technology and a light-sensitive detector, then Micro-Electro-Mechanical System (MEMS) processing technology was used to form a stable integrated structure. Experiments were performed based on the ammonium molybdate spectrophotometric method, including the preparation of phosphorus standard solution, reducing agent, chromogenic agent and color reaction. The device can obtain a wide linear response range (0.05 mg/L up to 7.60 mg/L), a wide reliable measuring range up to 10.16 mg/L after using a novel algorithm, and a low limit of detection (0.02 mg/L). The size of flow cell in this design is 18 mm × 2.0 mm × 800 µm, obtaining a low reagent consumption of 0.004 mg ascorbic acid and 0.011 mg ammonium molybdate per determination. Achieving these advantages of miniaturized volume, high precision and low cost, the design can also be used in automated in situ detection.
ABSTRACT
Primary malignant lymphoma of the breast (PLB) is a rare disease. Treatment options include surgical resection, systemic chemotherapy, radiation and immunotherapy. At present, the optimum treatment combination remains controversial. The present study reports the case of a 39-year-old female with a six month history of a painless mass in the left breast. The mass was excised following medical examination. A diagnosis of diffuse large B-cell lymphoma was determined as a result of histological and immunohistochemical profile analysis. Further examinations excluded metastatic disease. Thus, finally, PLB (diffuse large B-cell lymphoma type) was diagnosed. The patient was treated with adjuvant systemic chemotherapy and consolidated radiation and a positive response was observed. During the 10 months of follow-up, no evidence of disease recurrence was identified. At present, the patient is scheduled for regular follow-up appointments. As the prevalence of PLB is increasing, the details of this rare case may aid clinicians treating similar patients, and highlight the importance of this disease.
ABSTRACT
To investigate the expression intensity and prognostic significance of TGF-ß1 protein in non-small cell lung cancer (NSCLC), immunohistochemistry was carried out in 194 cases of NSCLC and 24 cases of normal lung tissues by SP methods. The PU (positive unit) value was used to assess the TGF-ß1 protein expression in systematically selected fields under the microscope with Leica Q500MC image analysis. We found that the TGF-ß1 PU value was nearly two-fold higher in NSCLC than in normal lung tissues (p=0.000), being associated with TNM stages (p=0.000) and lymph node metastases (p=0.000), but not to patient age, gender, smoking history, tumor differentiation, histological subtype and tumor location (P>0.05). Univariate analysis indicated that patients with high TGF-ß1 protein expression and lymph node metastases demonstrated a poor prognosis (both p=0.000, ). Multivariate analysis showed that TGF-ß1 protein expression (RR = 2.565, p=0.002) and lymph node metastases (RR=1.874, p= 0.030) were also independent prognostic factors. Thus, TGF-ß1 protein expression may be correlated to oncogenesis and serve as an independent prognostic biomarker for NSCLC.
