A dynamical model of the transport of asbestos fibres in the human body

We present a model for the transport of a single type of asbestos fibre through the human body. The model captures the transport modes that pertain particularly to the lungs and the mesothelium. Numerical solutions of the system follow observed movement in the body. We compare the accumulation of fibres in the lungs versus the mesothelium, and then we give analysis and results for various cases of exposure level and exposure time. Models, such as the one developed here, can give clues as to how asbestos fibres impact the body, and where to look for major impact.     

A retrospective cohort study of cancer mortality in employees of a Russian chrysotile asbestos mine and mills: Study rationale and key features

Chrysotile, a serpentine asbestos fibre, is the only type of asbestos produced and consumed in the world today. It is an established human carcinogen. We have begun fieldwork on a retrospective cohort study of employees of one of the world's largest chrysotile mine and mills, situated in Asbest, Russia. The primary aim of the study is to better characterize and quantify the risk of cancer mortality in terms of (i) the dose–response relationship of exposure with risk; (ii) the range of cancer sites affected, including female-specific cancers; and (iii) effects of duration of exposure and latency periods. This information will expand our understanding of the scale of the impending cancer burden due to chrysotile, including if chrysotile use ceased worldwide forthwith. Herein we describe the scientific rationale for conducting this study and the main features of its study design.     

Peritoneal mesothelioma mortality in Italy: Spatial analysis and search for asbestos exposure sources

BackgroundThis study is part of a national plan of epidemiological surveillance of malignant mesothelioma (MM) mortality in Italy. The paper shows the results of malignant peritoneal mesothelioma (MPeM) mortality study in Italian Regions and municipalities.MethodsNational Bureau of Statistics data for MPeM municipal mortality (ICD-10, Code C45.1) were analyzed in the time-window 2003–2014: mortality standardized rates (reference Italian population, census 2011), temporal trends of the annual national rates, Standardized Mortality Ratios and a municipal clustering analysis were performed.Results747 deaths for MPeM were recorded (0.10/100,000): 464 in men (0.14/100,000) and in 283 women (0.07/100,000). No significant MPeM mortality temporal trend was found.Seventeen municipalities showed excesses of mortality for MPeM in at least one gender and/or overall population.Four clusters in male population, and one in women were identified.ConclusionsThe study identifies some areas where remediation activities and/or health care actions may be warranted.     

Responses of antioxidants in the lichen Ramalina lacera may serve as an early-warning bioindicator system for the detection of air pollution stress

The aim of this study was to identify, in the lichen Ramalina lacera, antioxidants that could provide indications of air pollution stress, and respond earlier than traditionally used structural/physiological parameters. The pollution-sensitive lichen R. lacera was transplanted from its relatively unpolluted natural habitat to two air-polluted sites for a period of up to 6 months. The superoxide dismutase and catalase activities, total water- and lipid-soluble low-molecular-weight antioxidant capacities and chlorophyll b/chlorophyll a ratios were assessed every 6 weeks. The earliest signs of oxidative stress were detected in the activities of fungal copper/zinc-superoxide dismutase, algal iron-superoxide dismutase and water-soluble low-molecular-weight antioxidants, which increased significantly as early as 42 days after exposure to pollution. Catalase activity increased in lichens transplanted to the polluted sites after 90 days. All activities decreased towards the end of the experiment. The impact of air pollution on R. lacera, using the traditionally employed parameter of chlorophyll b/chlorophyll a ratio, was only detected after 6 months of exposure to air pollution. Our results indicate that antioxidant parameters may serve as improved early-warning indicators of air pollution stress in lichens.     

Biopersistent fiber-induced inflammation and carcinogenesis: Lessons learned from asbestos toward safety of fibrous nanomaterials

Nano-sized durable fibrous materials such as carbon nanotubes have raised safety concerns similar to those raised by asbestos. However, the mechanism by which particulates with ultrafine structure cause inflammation and ultimately cancer (e.g. malignant mesothelioma and lung cancer) is largely unknown. This is partially because the particulates are not uniform and they vary in a plethora of factors. Such variances include length, diameter, surface area, density, shape, contaminant metals (including iron) and crystallinity. Each of these factors is involved in particulate toxicity both in vitro and in vivo. Thus, the elicited biological responses are incredibly complicated. Various kinds of fibers were evaluated with different cells, animals and methods. The aim of this review is to concisely summarize previous reports from the standpoint that activation of macrophages and mesothelial injury are the two major mechanisms of inflammation and possibly cancer. Importantly, these two mechanisms appear to be interacting with each other. However, there is a lack of data on the interplay of macrophage and mesothelium especially in vivo. Since fibrous nanomaterials present potential applications in various fields, it is necessary to develop standard evaluation methods to minimize risks for human health.     

Calcium oxalate and sulphate-containing structures on the thallial surface of the lichen Ramalina lacera: response to polluted air and simulated acid rain

The formation of calcium‐containing structures on the thallial surface of the lichen Ramalina lacera (With.) J.R. Laund. in response to air pollution and to simulated acid rain, was studied in in situ and transplanted thalli. In situ thalli were collected from an unpolluted site and transplanted to heavily polluted and less polluted sites for a 10 month period. Additional thalli were treated either with double distilled water or with simulated acid rain. Scanning electron microscopy and infrared spectrometry revealed that thallial surfaces of in situ R. lacera samples collected in unpolluted sites were covered with two kinds of calcium oxalate crystals: whewellite and weddellite. These aggregates of calcium oxalate crystals appear to disintegrate and provide a crystal layer on the thallial surface. Infrared spectroscopy of powder scraped from thallial surfaces of transplants, retrieved from non‐polluted sites, showed the presence of whewellite and weddellite, whereas powders obtained from thalli retrieved from polluted sites contained whewellite, weddellite and gypsum. It is suggested that a certain fraction of the gypsum detected in crater‐like structures in transplants from polluted sites and in thalli treated with simulated acid rain is endogenous and should be considered a biomineral.     

Water and vapor transport in algal-fungal lichen: Modeling constrained by laboratory experiments,an application for Flavoparmelia caperata

Algal-fungal symbionts share water, nutrients, and gases via an architecture unique to lichens. Because lichen activity is controlled by moisture dynamics, understanding water transport is prerequisite to understand their fundamental biology. We propose a model of water distributions within foliose lichens governed by laws of fluid motion. Our model differentiates between water stored in symbionts, on extracellular surfaces, and in distinct morphological layers. We parameterize our model with hydraulic properties inverted from laboratory measurements of Flavoparmelia caperata and validate for wetting and drying. We ask: (1) Where is the bottleneck to water transport? (2) How do hydration and dehydration dynamics differ? and (3) What causes these differences? Resistance to vapor flow is concentrated at thallus surfaces and acts as the bottleneck for equilibrium, while internal resistances are small. The model captures hysteresis in hydration and desiccation, which are shown to be controlled by nonlinearities in hydraulic capacitance. Muting existing nonlinearities slowed drying and accelerated wetting, while exaggerating nonlinearities accelerated drying and slowed wetting. The hydraulic nonlinearity of F. caperata is considerable, which may reflect its preference for humid and stable environments. The model establishes the physical foundation for future investigations of transport of water, gas, and sugar between symbionts.     

Phenotypic variability and therapeutic implications of Candida species in patients with oral lichen planus

We investigated the prevalence and phenotypic variation of Candida species in oral lichen planus (OLP) and the therapeutic implications of our findings. Eighty patients with clinically and histopathologically confirmed cases of OLP (64 non-erosive, 16 erosive) and a control group of 80 healthy individuals with no predisposing factors for oral candidiasis were examined for evidence of Candida infection. Oral swabs and smears were obtained for cytology and culture. Identification, speciation and antifungal susceptibility tests of Candida isolates were performed using an automated microbial identification system. Fifty percent of erosive OLP cases, 28% of non-erosive cases and none of the controls showed evidence of Candida. Candida albicans was found predominantly in non-erosive OLP, while other Candida species were predominate in erosive OLP. Non-Candida albicans isolates (C. glabrata, C. krusei) were resistant to the commonly used antifungals, clotrimazole and fluconazole. Candida infection is common in cases of OLP. We recommend antifungal sensitivity testing prior to antifungal therapy for the erosive form of OLP.     

中国食药用地衣资源综述

中国食药用地衣历史悠久,本文从《诗经·小雅》到现代文献中考证了所记载的地衣物种名称及用途,结合民间调查,列出了民间药用地衣130种,隶属于16个科和43个属,以及食用地衣31种,隶属于7个科和14个属。提出曲金丝等分布范围狭窄、生态环境特殊和具有重要科学意义的物种的保护建议。     

Occurrence of fungi in air and on plants in vegetation of different climatic regions in Croatia

Research was carried out onthe presence and variation in occurrence offungal genera in air and on plant samplescollected from three different climatic regionsin Croatia in relation to temperature andrelative humidity throughout one year (1998).The sampling method employed in this study wasexposure of 150 Sabouraud agar plates withantibiotics to the air for 10 min. and byplacing 10 pieces of each plant sample (N = 150)on same agar. The spores belonging to 15 fungalgenera and sterile mycelim were identified.Cladosporium (65.3–74%),Penicillium (4.43–13.9%), Alternaria(2–4.7%), and sterile mycelium (7.4–15%) werethe most prevalent fungi in the air of all threeclimatic regions, while Fusarium(20.3–36.2%) was the most prevalent fungalgenera on plant samples especially in the modestcontinental climate. Significant differenceswere obtained for comparative fungalcontamination of air and plant samples, and bycomparing monthly occurrence in all three partsincluded. The climate factors and presence ofvegetation that produce essential oils withfungicide activity may be the reason for reducedfungal contamination of outdoor environments inthe Mediterranean climate.     

Expansins in Plant Growth and Development: an Update on an Emerging Topic

Abstract: Expansins are a class of proteins identified by their ability to induce the extension of isolated plant cell walls. Expansins are encoded by an extensive multigene family in higher plants, several members of which have been shown to be expressed in a tissue-specific manner. Besides playing an apparently key role in wall expansion, and hence in cell growth, expansins have been implicated in an increasing number of processes during plant growth and development. These include: leaf organogenesis, fruit softening, and wall disassembly. A second class of closely related proteins (referred to as β-expansins) has been identified. Other recent advances in expansin research include the recovery of transgenic plants with altered level of expansins, and the production of recombinant expansins in het-erologous expression systems.     

Degradation of xenobiotic compounds in situ: Capabilities and limits

Abstract: Exploiting microorganisms for remediation of waste sites is a promising alternative to groundwater pumping and above ground treatment. The objective of in situ bioremediation is to stimulate the growth of indigenous or introduced microorganisms in regions of subsurface contamination, and thus to provide direct contact between microorganisms and the dissolved and sorbed contaminants for biotransformation. Subsurface microorganisms detected at a former manufactured gas plant site contaminated with coal tars mineralized significant amounts of naphthalene (8–43%) and phenanthrene (3–31%) in sediment-water microcosms incubated for 4 weeks under aerobic conditions. Evidence was obtained for naphthalene mineralization (8–13%) in the absence of oxygen in field samples. These data suggest that biodegradation of these compounds is occurring at the site, and the prospects are good for enhancing this biodegradation. Additional batch studies demonstrated that sorption of naphthalene onto aquifer materials reduced the extent and rate of biodegradation, indicating that desorption rate was controlling the biodegradation performance.     

Exiguobacterium: an overview of a versatile genus with potential in industry and agriculture

The bacterial genus Exiguobacterium accommodates many versatile species isolated from diverse environments. Exiguobacterium was described as a genus approximately three decades ago, and now, 17 species, growing over a broad range of temperatures and pH, have been recognized. Various isolates from different niches have been explored for biotechnological and industrial purposes, including enzyme production, bioremediation and degradation of toxic substances released into the environment. Some isolates possess plant growth promoting capabilities, and they are currently being explored for increasing agricultural production. The genome sequences of various strains of this genus have shown the presence of many genes encoding products of importance to agriculture and the environment. In addition, many strains possess stress-responsive genes helping them to colonize and thrive in diverse ecological niches. This review provides a broad view of the versatile genus Exiguobacterium and its potential for applications in agriculture, the environment and industry, as well as the underlying genomic determinants that drive its diversity and adaptability to various extreme environments.     

Apoptosis induced by crocidolite asbestos in human lung epithelial cells involves inactivation of Akt and MAPK pathways

Exposure of human lung epithelial (A549) cells to asbestos fibers causes apoptosis, which is largely attributed to release of iron and generation of reactive oxygen species (ROS) within the cells. To mimic the highly oxidative environment generated by asbestos exposure in the absence of the actual fibers, we used two chemicals; buthione sulfoximine (BSO), an inhibitor of glutathione (GSH) synthesis and ferric ammonium citrate (FAC), a source of iron. Here, we report that exposure of A549 cells to crocidolite asbestos led to a significant time-dependent inactivation of signaling proteins, i.e. Akt and all mitogen-activated protein kinases (MAPKs) (p38, ERK1/2 and SAPK/JNK), and subsequently to apoptosis. Unlike crocidolite treatment, the use of BSO and FAC, independently or combined, did not change the phosphorylation status of proteins, nor did it induce apoptosis. Taken together, our results presented herein point to the possibility that crocidolite-induced apoptosis of human lung epithelial cells is not a mere consequence of generation of oxidants but also requires inactivation of major cell growth and differentiation pathways. A. Baldys, P. Pande contributed equally to this publication.     

Detection and identification of non-Candida albicans species in human oral lichen planus

Candida species were detected and identified in samples from the buccal mucosa, dorsal surface of the tongue and supragingival plaque of subjects with oral lichen planus (OLP). The Candida in the samples were cultured on selection agars, and identified by sequence analyses of 18S, 5.8S and 25/28S rRNA. The isolation frequency of Candida was higher in subjects with OLP than in those with healthy oral mucosa. Non-C. albicans were only isolated from people with OLP. These results support the notion that subjects with OLP are more likely to have oral colonization with Candida, and that non-C. albicans are specifically present in subjects with this condition.     

广东英德石灰岩地区植物多样性研究

据调查,英德石灰岩地区有维管植物99科199属245种,数量优势科为大戟科、蝶形花科、兰科和凤尾蕨科等;科、属的地理分布均以热带亚热带成分为主;有伞花木属Eurycorymbus、青檀属Pteroceltis等7个中国特有属;有圆叶乌桕Sapium rotundifolium、任豆Zenia insignis等15个石灰岩特有种;有伞花木Eurycorymbus cavaleriei等珍稀濒危植物5科13属15种;植被优势种为龙眼Dimocarpus longan、假苹婆Sterculia lanceolata、海红豆Adenanthera pavonina var. microsperma、阴香Cinnamomum burmanni等。基于石灰岩生境的特殊性,建议加强对其植物多样性保护。     

广州南沙区植物多样性及植被类型

通过实地调查,对广州南沙区的植物多样性及植被进行了研究。据统计,该区野生维管束植物共有603种,隶属于128科,388属;植被主要为湿生植被、水生植被、滩涂植被及丘陵植被等。对南沙区野生植物多样性和区系地理的分析结果表明：该地区物种集中于少数科内,科属的优势现象明显。在植物区系上,该区具有较强的热带性,但温带成分也有一定程度的入侵。最后对该区植物多样性的保护提出建议。     

Modelling Environmental Responses of Plant Associations: A Review of Some Critical Concepts in Vegetation Study

The definition of vegetation types at different hierarchical levels, both to study the vegetation processes and for practical cartographic representation, is still considered a critical issue in many circles of plant ecologists. The problems are mainly related to the misleading idea that classification of the vegetation system, as developed by European phytosociologists during the last century within the discipline called syntaxonomy, would imply the assumption of the organismic concept of the plant community. After a short discussion on the role of Braun-Blanquet approach in plant ecology and in landscape ecology, the methods to detect multispecies responses along environmental gradients are briefly reviewed. In the main part of this article, we intend to stress that concepts considered critical, such as plant association and its ecological niche, are just operational tools that have nothing to do with the individualistic or organismic interpretation of plant communities in vegetation studies. Important to our views on vegetation, we believe that plant associations as well as the higher syntaxa can be regarded as fuzzy sets in an operational context for describing vegetation along ecological gradients in synthetic ways and can further the understanding of vegetation variation.     

乌鲁木齐南部山区岩面生地衣群落特征的研究

应用多元分析中的主分量分析及聚类分析方法对分布在乌鲁木齐南部山区森林生态系统中岩面生地衣群落进行数量分类并对群落结构物种多样性、相似性和均匀度等群落参数进行了比较系统的研究。结果表明,乌鲁木齐南部山区的岩面生地衣共计49种,隶属于4目13科23属,岩面生地衣形成3种群落:(1)湿润石生地衣群落(Hygro-lichen community)定名为疣微孢衣Acarospora verruculosa+粉盘平茶渍A.alphaplaca+斑纹网衣Lecidea tessellata群落;(2)干燥石生地衣群落(Xero-lichen community)定名为多形茶渍Lecanora polytropa+破小网衣Lecideacarpathica群落;(3)高山石生地衣群落(Alpino-lichen community)定名为不等瓶口衣Verrucaria iaequalis+皮果衣Dermatocarpon miniatum群落。同时发现在乌鲁木齐南部山区森林生态系统中岩面生地衣群落的分布与海拔高度和基物的种类有密切的关系,不同海拔的不同类型的森林生态系统中分布着不同种类的岩面生地衣。