Environmental risk assessment of manganese and its associated heavy metals in a stream impacted by manganese mining in South China

In South China, high manganese content in the drinking water source influenced by upstream manganese mine drainage has become a major concern. To investigate the extent of metal pollution and environmental risk in upstream sediments and native aquatic macrophytes, a study was conducted on a manganese mining-impacted river named the Heishui River. The results indicated that streambed sediments collected were polluted by Mn and other metals with the highest contents of Mn 43349.4 mg kg^?1, Pb 128.6 mg kg^?1, Zn 502.9 mg kg^?1, and Cu 107.2 mg kg^?1. The level of Mn in all sediments was higher than the consensus-based Probable Effect Concentration, indicating that adverse effects on sediment-dwelling organisms were likely to occur frequently. Among the studied metals, Mn had the highest bioavailability and ecological risk, followed by Zn. Native aquatic macrophytes accumulate large amounts of the studied metals. A significantly positive correlation was found between exchangeable fractions of the studied metals in sediments and in aquatic macrophytes. The risk assessment code showed the following risk levels of metals in sediments in descending order: Mn > Zn > Cu > Pb. In conclusion, the river impacted by manganese mining drainage poses a high risk to both the local ecosystem and downstream drinking water.     

Distinct Biology of Kaposi’s Sarcoma-Associated Herpesvirus from Primary Lesions and Body Cavity Lymphomas

The DNA sequence for Kaposi’s sarcoma-associated herpesvirus was originally detected in Kaposi’s sarcoma biopsy specimens. Since its discovery, it has been possible to detect virus in cell lines established from AIDS-associated body cavity-based B-cell lymphoma and to propagate virus from primary Kaposi’s sarcoma lesions in a human renal embryonic cell line, 293. In this study, we analyzed the infectivity of Kaposi’s sarcoma-associated herpesvirus produced from these two sources. Viral isolates from cultured cutaneous primary KS cells was transmitted to an Epstein-Barr virus-negative Burkitt’s B-lymphoma cell line, Louckes, and compared to virus induced from a body cavity-based B-cell lymphoma cell line. While propagation of body cavity-based B-cell lymphoma-derived virus was not observed in 293 cell cultures, infection with viral isolates obtained from primary Kaposi’s sarcoma lesions induced injury in 293 cells typical of herpesvirus infection and was associated with apoptotic cell death. Interestingly, transient overexpression of the Kaposi’s sarcoma-associated herpesvirus v-Bcl-2 homolog delayed the process of apoptosis and prolonged the survival of infected 293 cells. In contrast, the broad-spectrum caspase inhibitors Z-VAD-fmk and Z-DEVD-fmk failed to protect infected cell cultures, suggesting that Kaposi’s sarcoma-associated herpesvirus-induced apoptosis occurs through a Bcl-2-dependent pathway. Kaposi’s sarcoma-associated herpesvirus isolates from primary Kaposi’s sarcoma lesions and body cavity-based lymphomas therefore may differ and are likely to have distinct contributions to the pathophysiology of Kaposi’s sarcoma.     

Hydrological regulation drives regime shifts: evidence from paleolimnology and ecosystem modeling of a large shallow Chinese lake

Quantitative evidence of sudden shifts in ecological structure and function in large shallow lakes is rare, even though they provide essential benefits to society. Such ‘regime shifts’ can be driven by human activities which degrade ecological stability including water level control (WLC) and nutrient loading. Interactions between WLC and nutrient loading on the long‐term dynamics of shallow lake ecosystems are, however, often overlooked and largely underestimated, which has hampered the effectiveness of lake management. Here, we focus on a large shallow lake (Lake Chaohu) located in one of the most densely populated areas in China, the lower Yangtze River floodplain, which has undergone both WLC and increasing nutrient loading over the last several decades. We applied a novel methodology that combines consistent evidence from both paleolimnological records and ecosystem modeling to overcome the hurdle of data insufficiency and to unravel the drivers and underlying mechanisms in ecosystem dynamics. We identified the occurrence of two regime shifts: one in 1963, characterized by the abrupt disappearance of submerged vegetation, and another around 1980, with strong algal blooms being observed thereafter. Using model scenarios, we further disentangled the roles of WLC and nutrient loading, showing that the 1963 shift was predominantly triggered by WLC, whereas the shift ca. 1980 was attributed to aggravated nutrient loading. Our analysis also shows interactions between these two stressors. Compared to the dynamics driven by nutrient loading alone, WLC reduced the critical P loading and resulted in earlier disappearance of submerged vegetation and emergence of algal blooms by approximately 26 and 10 years, respectively. Overall, our study reveals the significant role of hydrological regulation in driving shallow lake ecosystem dynamics, and it highlights the urgency of using multi‐objective management criteria that includes ecological sustainability perspectives when implementing hydrological regulation for aquatic ecosystems around the globe.     

Brain-Derived Neurotrophic Factor Increases Synaptic Protein Levels via the MAPK/Erk Signaling Pathway and Nrf2/Trx Axis Following the Transplantation of Neural Stem Cells in a Rat Model of Traumatic Brain Injury

Brain-derived neurotrophic factor (BDNF) plays an important role in promoting the growth, differentiation, survival and synaptic stability of neurons. Presently, the transplantation of neural stem cells (NSCs) is known to induce neural repair to some extent after injury or disease. In this study, to investigate whether NSCs genetically modified to encode the BDNF gene (BDNF/NSCs) would further enhance synaptogenesis, BDNF/NSCs or naive NSCs were directly engrafted into lesions in a rat model of traumatic brain injury (TBI). Immunohistochemistry, western blotting and RT-PCR were performed to detect synaptic proteins, BDNF-TrkB and its downstream signaling pathways, at 1, 2, 3 or 4 weeks after transplantation. Our results showed that BDNF significantly increased the expression levels of the TrkB receptor gene and the phosphorylation of the TrkB protein in the lesions. The expression levels of Ras, phosphorylated Erk1/2 and postsynaptic density protein-95 were elevated in the BDNF/NSCs-transplanted groups compared with those in the NSCs-transplanted groups throughout the experimental period. Moreover, the nuclear factor (erythroid-derived 2)-like 2/Thioredoxin (Nrf2/Trx) axis, which is a specific therapeutic target for the treatment of injury or cell death, was upregulated by BDNF overexpression. Therefore, we determined that the increased synaptic proteins level implicated in synaptogenesis might be associated with the activation of the MAPK/Erk1/2 signaling pathway and the upregulation of the antioxidant agent Trx modified by BDNF-TrkB following the BDNF/NSCs transplantation after TBI.     

Precise mapping of a quantitative trait locus interval for spike length and grain weight in bread wheat (Triticum aestivum L.)

The spike characteristics length, spikelet density and fertile floret number are related yield components and are important in cereal improvement. QSpl.nau-2D is a major quantitative trait locus controlling spike length (SPL) detected in the recombinant inbred line population developed by crossing wheat (Triticum aestivum) cultivars Nanda2419 with Wangshuibai. In this study, to validate its genetic effect and determine its precise location, QSpl.nau-2D’s near-isogenic line (NIL) was developed using Mianyang99-323 as the recurrent parent through marker-assisted selection. Field trials showed that the NIL not only had significantly longer spikes on average than the recurrent parent but also had significantly higher grain weight, but did not differ in spikelet number and kernel number per spike. In the F2 population derived from a cross of the NIL with Mianyang99-323, QSpl.nau-2D functioned like a single gene and conditioned the SPL in a partially dominant manner, and was thus designated as HL1 (for head length). To precisely map HL1, 89 recombinants, consisting of 11 genotypes, were identified in the NIL-derived F2 population of 674 plants by using markers in the Xwmc25–Xgpw4080 interval. Phenotyping these lines showed that the introduction of a 0.9-cM interval flanked by Xcfd53 and DG371 in Nanda2419 resulted in longer spikes and a higher grain weight in the NIL. The availability of markers closely linked to HL1 could facilitate its use in breeding programs.     

试论福建海岛植物资源的保护、改造及合理开发利用

本文阐述了福建沿海海岛植被及植物资源的现状;指出其存在的资源严重衰退、树种组成简单、森林生态效益差、果林生产落后、农业植被单一等问题;针对这些问题提出了切实有效的保护现有各类植被,发展针闲叶混交防护林,加快沙荒及荒山绿化,积极发展经济果林及旅游林业等建议,为各地开发海岛资源、振兴海岛经济提供参考。     

长春花黄化植原体（PY）株系的检测与鉴定

植原体 (Ｐｈｙｔｏｐｌａｓｍａ) (原称类菌原体Ｍｙｃｏｐｌａｓｍａ ｌｉｋｅＯｒｇａｎｉｓｍ ,简称ＭＬＯ)是一类无细胞壁、存在于植物筛管细胞内的原核生物。植原体自 1 967年被日本学者土居养二首次发现后 ,迄今为止 ,世界上报道的植物植原体病害多达 30 0余种 ,早期对植原体的鉴定主要是通过生物学特性 ,如症状特征、与昆虫介体的相互关系等进行的。这些方法费时费力 ,结果往往也不是很可靠。 80年代 ,随着血清学、分子探针以及ＰＣＲ技术的发展应用 ,为植原体的检测提供了一种相对简单、灵敏、可靠的方法。通过对 1 6ＳｒＲＮＡ基…     

奇异果甜蛋白及其基因工程

奇异果甜蛋白(thaumatin)是迄今为止最甜的物质之一,对其研究具有很重要的意义。奇异果甜蛋白的生化性质基本清楚,基因序列和氨基酸序列都已测定。它的甜味可能是由奇异果甜蛋白上特定基团和受体结合引起的。对奇异果甜蛋白的生理功能知之甚少。近二十年来,在奇异果甜蛋白的基因工程上取得了一定进展,但仍然存在许多困难。 Abstract:Thaumatin is one of the sweetest substances known to date,it is important to study the thaumatin.The biochemical properties of thaumatin have been clarified clearly.Thaumatin had been isolated and sequenced.The mechanism of the sweetness of thaumatin may be due to the combination of some special groups and the receptors.The exact function of thaumatin is still not clear.Although gene engineering of thaumatin has been carried out for 20 years,there are still some difficulties to be solved for using in the market.