石质文物的生物风化及其防治研究进展

石质文物的生物风化问题普遍存在,随着全球气候与环境变化加剧,其面临的生物风化挑战日趋严峻,防风化任务愈趋紧迫.本文综述了地衣类微生物介导的石材风化机理及其与气候环境因子间的关系,讨论了地衣的生物保护作用和地衣防治中生物杀灭剂的效力评价,并展望了该领域未来的研究方向.对地衣-岩石界面的大量研究表明,生物风化可主要归因于以菌丝穿透和草酸钙形成为代表的生物物理风化和生物化学风化;露天石质文物的生物风化与包括石材基质、周边环境及气候因素等在内的整个生态系统多种非生物条件息息相关;地衣对石材兼具生物风化作用和生物保护效应.在石质文物风化修复方面,应逐步改善文物赋存的环境条件,建立用于生物风化和杀灭效率评估的行业规范和国家标准等“通用语言”,推进石质文物的科学保护.     

石质文物地衣生物腐蚀及防治的研究进展

本文主要从生物因素方面考虑,分析了导致石质文物病害的主要原因和机理,并综述了国内外石质文物保护的现状、防治和修复方法。地衣是引起石质文物腐蚀的关键生物类群,与国外相比,目前国内专门针对地衣进行石质文物防治的研究鲜见报道。作者建议,石质文物的地衣生物腐蚀及防治研究应从以下方面入手：（1）石质文物地衣必须首先进行系统的种类调查;（2）对地衣腐蚀石质文物的机理进行深入研究;（3）探寻地衣病害安全有效的去除方法;（4）逐步探索地衣病害修复后的监测和预防方法。     

石质文物微生物检测技术的研究进展

本论文针对国内外最新的石质文物微生物的检测技术进行了论述,主要包括核酸分析鉴定方法、细胞膜分析法、次级代谢产物分析法和传统培养法等。并综合比较各种方法的优势和不足,对石质文物的生物保护提出展望。石质文物微生物的无损或微损快速检测技术的建立,对于进一步清理石质文物的微生物污染,有效防治微生物对石质文物的腐蚀,保护我国宝贵的文化遗产具有重要的意义。     

几种常见真菌毒素脱毒方法的研究进展

真菌毒素是真菌在生长过程中所产生的一些次级代谢产物,广泛存在于谷物和饲料中,对人畜健康危害极大。常见的真菌毒素有:黄曲霉毒素、赭曲霉毒素、玉米赤霉烯酮、脱氧雪腐镰刀菌烯醇、T-2毒素、伏马菌素等。真菌毒素的脱毒主要是指破坏、除去以及减少粮食中毒素毒害的收获后处理。在现有的脱毒方法中,物理脱毒方法包括蒸煮、吸附、辐射等,化学脱毒方法包括添加化学物质和杀菌剂等,生物脱毒方法包括微生物吸附和微生物降解等。本文对常见真菌毒素的脱毒方法以及其它最新的脱毒方法进行了综述。     

氧化亚铁硫杆菌对金属铜的加工

材料加工的传统技术包括物理方法和化学方法。当今 ,生物技术已进入各个领域 ,也渗透到材料加工领域。因此 ,材料加工技术也包括生物方法。根据加工工件体积变化 ,生物方法加工分为生物去除加工 (Ｒｅｍｏｖａｌ)、生物沉积加工 (Ａｄｄｉｔｉｏｎ)和生物成形加工 (Ｄｅｆｏｒｍａｔｉｏｎ)。研究生物加工方法的最早报导是 1 993年日本冈山大学宇野义幸等人[1～ 3] ,证实了细菌对纯铁、纯铜去除加工的可能性以及附加电场的作用。国内的研究工作进一步证实了生物加工能力 ,并加工出微小齿轮[4～5] 。本文报导氧化亚铁硫杆菌 (Ｔｈｉｏｂａｃ…     

新型杀菌剂Biosperse XD3899在循环水系统中微生物控制的性能评估

清洁的系统表面对循环水系统的正常运行至关重要。生物粘泥的大量繁殖会产生严重的系统问题,使管道堵塞,换热器的换热效率下降,水质恶化,引起管道垢下腐蚀,而这些问题都将导致系统维护费用增加,运行成本提高,并直接降低了系统寿命。生物粘泥的控制措施除定时排污外,投加杀菌剂是去除生物粘泥最为直接有效的方法。常规的氧化型杀菌剂易受循环水中有机物料、阻垢缓蚀剂等的影响和干扰,使之杀菌效果降低;而非氧化型杀菌剂虽然不易受物料影响,但是由于大部分非氧化型杀菌剂使用成本较高,再者,长期大量使用容易产生抗药性,使之杀菌效果降低。本文着重介绍了对生物粘泥具有极强的剥离作用,同时可有效抑制生物粘泥再生的一种新型弱氧化型杀菌剂Biosperse XD3899。通过实验室模拟、现场应用,对其剥离以及抑制性能进行了评估。实验结果显示,Biosperse XD3899在高有机物料水体中对活菌数的控制效果远远高于常规的氧化型及非氧化型杀菌剂,可有效抑制生物粘膜形成;同时,对于系统中已经形成的生物粘泥具有很好的剥离效果。     

环二鸟苷酸——新型的细菌第二信使

环二鸟苷酸(cyclic diguanylate,c-di-GMP)是新近发现的在细菌中普遍存在的第二信使分子,参与调节多种生理功能,包括细胞分化、从运动状态到生物被膜状态的转变、致病因子产生等.基于其对细菌抗生素耐药的物理屏障—生物被膜形成的影响,c-di-GMP的研究越来越受到人们的关注.细胞内c-di-GMP的产生受二鸟苷酸环化酶(diguanylate cyclase,DGC)合成和磷酸二酯酶(phosphodiesterase,PDE)降解两条途径调控.在结构上,通常DGC含有GGDEF结构域,PDE含有EAL结构域.c-di-GMP的作用靶点包括PilZ结构域和GEMM 核开关两种类型.本文综述了c-di-GMP的代谢途径、调控机理、生物学功能等方面的最新研究进展,并对c-di-GMP在今后研究中的应用和发展趋势进行展望.     

海洋沉积物中重金属对底栖无脊椎动物的生物有效性

海洋沉积物是重金属的重要贮库,而海洋底栖无脊椎动物主要从沉积物中摄取重金属,这些被摄取的重金属能够通过食物链进行传递,进而影响到人类健康。本文总结了近些年来在海洋沉积物中重金属对底栖无脊椎动物生物有效性方面的研究进展,包括海洋底栖无脊椎动物对重金属的吸收途径、沉积物地球化学性质和底栖无脊椎动物生理等生物因素对沉积物中重金属生物有效性的影响。在此基础上,展望了未来研究重点,主要包括近海富营养化对沉积物中重金属生物有效性的影响,海洋底栖无脊椎动物消化道中的物理消化过程对沉积物中重金属生物有效性的影响,海洋底栖无脊椎动物整个生活史过程中沉积物中重金属生物有效性的变化等。     

桔小实蝇生物学特点及其防治研究概述

桔小实蝇Bactrocera(Bactrocera)dorsalis(Hendel)是危害热带、亚热带水果的重要检疫性害虫之一,本文综述了桔小实蝇主要生物学、生态学特点和防治措施的研究进展,包括桔小实蝇在国内的总体分布情况,对寄主的选择差异,各虫态的形态特征、发育历期和不同因子对其生长发育的影响,生活史以及农业防治、化学农药防治、诱杀防治、生物防治、物理防治等不同防治方法的研究和应用情况,并对今后的研究提出一些建议。     

细菌生物被膜（bacterial biofilm）的研究进展

细菌生物被膜由物体表面集聚生长的细菌群落和细胞外基质构成 ,植入性医用器械表面较多见 ,其结构包括主体生物被膜层、连接层、条件层和基质层。细菌之间的信号传导影响着生物被膜的异化形成。生物被膜相关感染治疗较难 ,易慢性化及反复发作。抗生素或其他化学杀菌剂及金银包裹导管等医用材料表面是常用的预防方法。已形成的生物被膜可用物理方法或某些抗生素清除 ,而生物学控制是另一可能途径。     

Biodeterioration of stone: a review

The alteration and weathering of stone is basically determined by natural and anthropogenic impacts influencing various physical, chemical and biological damage factors at the object site. Whether as direct or catalytically enhancing factor, the biodeterioration of stone is coupled with nearly all environmentally induced degradation processes: the presence of the one makes deterioration by the other all the more effective. The bioreceptivity of stone is described by its structure and chemical composition, while the intensity of the microbial contamination is determined by the referring climatic conditions and the anthropogenic euthrophication of the atmosphere. The microflora improves the nutrient and moisture-restricted growth conditions on building stones by the formation of surface-covering biofilms. Besides the aesthetical impairment caused by the coloured biopatina, the biofouling effect promotes even “abiotic” deterioration processes due to the alteration of the material structure as well as their thermo-hygric properties; in addition, mechanical pressure due to the shrinking and swelling of the colloidal biofilms might cause a further weakening of the mineral lattice. Acidolytic and oxido-reductive biocorrosion processes complete the biodeteriorating attack of stone acting as a preliminary precursor for the latter formation of detrimental crusts. Suitable and reliable methods for the detection of biodeterioration processes are available, but only the interdisciplinary diagnosis and evaluation of the entire decay process of stone allows the formulation of adaequate countermeasure strategies. In case the significance of biodeterioration impacts is proven, the possible effects of the microbial contamination on cleaning procedures, protective treatments as well as biocidal applications has to be considered. This paper will give a comprehensive overview to the biodeterioration of stone and stresses the practical relevance for the conservation.     

Microbial deterioration of cultural heritage and works of art — tilting at windmills?

Microorganisms (bacteria, archaea and fungi), in addition to lichens and insect pests, cause problems in the conservation of cultural heritage because of their biodeteriorative potential. This holds true for all types of historic artefacts, and even for art made of modern materials, in public buildings, museums and private art collections. The variety of biodeterioration phenomena observed on materials of cultural heritage is determined by several factors, such as the chemical composition and nature of the material itself, the climate and exposure of the object, in addition to the manner and frequency of surface cleaning and housekeeping in museums. This study offers a review of a variety of well-known biodeterioration phenomena observed on different materials, such as stone and building materials, objects exhibited in museums and libraries, as well as human remains and burial-related materials. The decontamination of infected artefacts, exhibition rooms and depots incurs high expenditure for museums. Nevertheless, the question has to be raised: whether the process of biodeterioration of cultural heritage can or should be stopped under all circumstances, or whether we have to accept it as a natural and an implicit consecution of its creation. This study also highlights critically the pros and cons of biocide treatments and gives some prominent examples of successful and unsuccessful conservation treatments. Furthermore, an outlook on the future research needs and developments in this highly interesting field is given.     

Measurement of limestone biodeterioration using the Ca2+ binding fluorochrome Rhod-5N

Limestone and marble have been used extensively in the construction of modern and historic buildings. Microbial colonization and growth on these stone structures is common. Microbial deterioration of stone has been assessed by measuring Ca2+ released from the stone, using ion selective electrodes and titration with EDTA. In this study, the calcium binding fluorochrome Rhod-5N was used to measure Ca2+ released from limestone by endolithic bacteria as an indicator of biodeterioration. In a 17 d flask experiment, Ca2+ released by endolithic bacteria was twice that of uninoculated controls. Rhod-5N is a rapid and accurate method for measuring microbial biodeterioration of stone.     

Bacterial Deterioration of Marble Monuments: A Case Study of the Conservation Project of Acropolis Monuments

The deterioration of the Acropolis monuments’ surface can be attributed to a combination of mechanical, physical, chemical and biological factors. The aim of this work was to investigate the potential use of biocides suitable for marble surface in order to confront the biodeterioration phenomenon due to heterotrophic bacteria. Surface bacterial populations were studied in respect to the application of three biocide agents. A significant decrease of the bacterial counts was occurred after the biocides’ application and remained less compared with the counts occurred on the untreated surfaces for more than 14 months. A gradual diminution of bacterial diversity was also observed leading to the survival of specific Gram positive strains.     

Surface analysis and materials characterization for the study of biodeterioration and weathering effects on cultural property

Several methods for material characterization and surface analysis such as scanning electron microscopy (SEM), energy dispersion X-ray analysis (EDX), environmental scanning electron microscopy (ESEM), petrographic analyses, Mössbauer spectroscopy (MS), conventional X-ray diffraction (XRD), grazing incidence diffraction (GID), Raman spectroscopy (RS), other spectroscopic techniques like X-ray photoelectron spectroscopy (XPS), reflection electron energy-loss spectroscopy (REELS) and advanced combined applications of synchrotron based μ-X-ray diffraction/μ-X-ray fluorescence (SR-μXRD/μXRF) can be used for assessing weathering and biodeterioration effects on materials (such as stone buildings, metallic artefacts, pigments, mixtures, and processes) of cultural property. Molecular biology techniques to identify the microbial components of biofilms are also described. Different examples of the use of these methods in the field of cultural property preservation are presented.     

Multistep approach to control microbial fouling of historic building materials by aerial phototrophs

The scientific multistep approach described herein is a result of two years of research into a control method against microbial fouling and biodeterioration of historic building materials by phototrophs. A series of tests were conducted to select the best antifouling agent for eliminating ‘green’ coatings and protecting surfaces against biofouling. Of the seven active compounds, two with the best penetration abilities were subjected to a photosynthetic activity inhibition test using confocal microscopy. Of the two, a quaternary ammonium salt (QAC) – didecyldimethylammonium chloride (DDAC) – was found to be the most effective. Ten biocides containing QACs at different concentrations were then tested against ‘green’ coatings on wood, brick and plaster, with the best four being selected for further research in model conditions. As a result, biocides containing >14% (v v^–1) DDAC were found to be successful antifouling agents for protecting historical materials against biodeterioration by phototrophs.     

Synthetic Consolidants Attacked by Melanin-Producing Fungi: Case Study of the Biodeterioration of Milan (Italy) Cathedral Marble Treated with Acrylics

Monuments and artistic stone surfaces are often consolidated and protected with synthetic polymers, in particular, acrylics. Although it is generally thought that acrylic polymers are resistant to biodeterioration, we report for the first time the systematic occurrence of dematiaceous meristematic fungi on many marble samples of the cathedral in Milan (Italy) previously treated with this material. Fourier transform infrared spectroscopy applied to the Milan cathedral stone samples revealed characteristic features of biodeteriorated synthetic resins that differentiated them from the aged but nonbiodeteriorated samples. Samples showing biological colonization were analyzed for the presence of fungi. Cultivation and morphological characterization and methods independent from cultivation, such as denaturing gradient gel electrophoresis coupled with partial 18S rRNA gene sequencing and immunofluorescence staining with melanin-binding antibodies, showed that melanin-producing species are heavily present on stone surfaces protected with acrylic resins. This observation raises the question of the effectiveness of acrylics in protecting stone artworks.     

Synthetic consolidants attacked by melanin-producing fungi: case study of the biodeterioration of Milan (Italy) cathedral marble treated with acrylics

Monuments and artistic stone surfaces are often consolidated and protected with synthetic polymers, in particular, acrylics. Although it is generally thought that acrylic polymers are resistant to biodeterioration, we report for the first time the systematic occurrence of dematiaceous meristematic fungi on many marble samples of the cathedral in Milan (Italy) previously treated with this material. Fourier transform infrared spectroscopy applied to the Milan cathedral stone samples revealed characteristic features of biodeteriorated synthetic resins that differentiated them from the aged but nonbiodeteriorated samples. Samples showing biological colonization were analyzed for the presence of fungi. Cultivation and morphological characterization and methods independent from cultivation, such as denaturing gradient gel electrophoresis coupled with partial 18S rRNA gene sequencing and immunofluorescence staining with melanin-binding antibodies, showed that melanin-producing species are heavily present on stone surfaces protected with acrylic resins. This observation raises the question of the effectiveness of acrylics in protecting stone artworks.