Virus attenuation by microbial mechanisms during the idle time of a household slow sand filter

The biosand filter (BSF) is a household slow sand filter that is operated intermittently such that an idle time of typically 18-22 h occurs in between daily charges of water. Virus attenuation during the idle time was investigated over repeated daily filtration cycles to capture the effect of media aging that encompasses processes occurring throughout the filter depth rather than restricted to the schmutzdecke at the media surface. A threshold aging period of about one to two weeks was required before virus attenuation began. The observed rates of MS2 and PRD-1 reduction were first-order and reached maxima of 0.061- and 0.053-log per hr, respectively, over seven-to-ten weeks. Suppression of microbial activity by sodium azide eliminated virus reduction during the idle time thus indicating that the operative media aging process was microbially mediated. The mechanism of virus reduction was not modification of media surfaces by physical/chemical or microbial processes. Instead, it appears that the activity of the microbial community within the filter is responsible. The most likely biological pathways are production of microbial exoproducts such as proteolytic enzymes or grazing of bacteria and higher microorganisms on virus particles. Implications of these findings for BSF design and operation and their relevance to other biological filtration technologies are discussed.     

浅析高校网络协同办公自动化的安全问题

二十一世纪是全球网络化、信息化急剧膨胀的时代,各大高校网络办公自动化技术的发展也越来越快,同时计算机病毒的肆虐,黑客的入侵等危害互联网的因素也危害到了各大高校的网络办公自动化。针对此问题,本文总结了网络办公自动化系统的发展现状及主要特点,列出常见的安全问题及其后果,探讨了解决这些安全问题的方法,提供了基于网络内部的安全策略。     

计算机病毒分析与防范的研究

当前,对信息领域构成极大威胁的是计算机病毒和木马。首先对计算机病毒和木马的生产、伪装等进行了详细的论述,其次研究了病毒的相关技术手段以及行为,进一步通过病毒例证详细分析、揭示了病毒产生的本质,最后针对病毒所采取的新的破坏手段加以预测和剖析,并提出了对预防病毒入侵的建议和解决方案。     

Varroosis – the Ongoing Crisis in Bee Keeping

Varroosis is the most destructive disease of honey bees worldwide, inflicting much greater damage and higher economic costs than all other known apicultural diseases. The disease pattern of Varroosis is not uniform, as both the rate of infestation and secondary infections determine the clinical symptoms. Brood and adults bees are impaired. The mite injures the bee through repeated intake of hemolymph with her chelicerae while the host is in the larval, pupal and adult stage. The loss of hemolymph negatively effects the organ development of the bee. Colonies infested by V. destructor develop the parasitic mite syndrome and ultimately collapse if left untreated. Favourable reproduction conditions in the new host A. mellifera, the increasing impact of secondary infections (viruses) and the lack of coordinated and comprehensive treatment strategies and control methods that are often implemented too late or unsuccessfully by the beekeeper result in reappearing wide spread colony losses. A viral infection vectored by V. destructor obviously increases its impact on colony collapses with the cause of this ongoing crisis. Varroa control should be a natural part of a beekeeper’s operation and flow into a system of Varroa control. The residues from Varroacide applications which are detectable today are all below the permitted maximum values. Although these minor detectable residues pose no threat to the consumer, they must be avoided in bee products, as honey possesses a very positive image in the mind of consumers. Received: February 20, 2008     

Shotgun metagenomics of dust microbiome from flight deck and cabin in civil aviation aircraft

Microbial exposure is related to the health of passengers on commercial aircraft, but no studies characterized the microbial composition at the species level and identified their ecological determinants. We collected vacuum dust from floor and seat surfaces in flight decks and cabins of 18 aircraft, and amplification-free shotgun metagenomics was conducted to characterize the microbial composition. In total, 7437 microbial taxa were identified. The relative abundance for bacteria, eukaryote, viruses, and archaea was 96.9%, 1.8%, 0.3%, and 0.03%, respectively. The top bacterial species mainly derived from outdoor air and human skin included Sphingomonas, Corynebacterium, Micrococcus luteus, Variovorax paradoxus, Paracoccus dentrificans, and Propionibacterium acnes. The abundance of NIAID-defined pathogens was low, accounted for only 0.23% of total microbes. The microbial species and functional composition were structured by the indoor surface type (R² = 0.38, Adonis), followed by the manufacturer of the aircraft (R² = 0.12) and flight duration (R² = 0.07). Indoor surfaces affected species derived from different habitats; the abundance of dry skin and desiccated species was higher on textile surfaces, whereas the abundance of moist and oily skin species was higher on leather surfaces. The growth rates for most microbes were stopped and almost stopped.     

Advances in Transgenic Mouse Models to Study Infections by Human Pathogenic Viruses

Medical research is changing into direction of precision therapy, thus, sophisticated preclinical models are urgently needed. In human pathogenic virus research, the major technical hurdle is not only to translate discoveries from animals to treatments of humans, but also to overcome the problem of interspecies differences with regard to productive infections and comparable disease development. Transgenic mice provide a basis for research of disease pathogenesis after infection with human-specific viruses. Today, humanized mice can be found at the very heart of this forefront of medical research allowing for recapitulation of disease pathogenesis and drug mechanisms in humans. This review discusses progress in the development and use of transgenic mice for the study of virus-induced human diseases towards identification of new drug innovations to treat and control human pathogenic infectious diseases.     

Bioinspired Artificial Tobacco Mosaic Virus with Combined Oncolytic Properties to Completely Destroy Multidrug-Resistant Cancer

Although biomimetic virus-like strategies have been widely used in antitumor applications, construction of uniquely shaped virus-like agents and optimization of their specific morphological features to achieve diverse antitumor functions are worthwhile pursuits. Here, a novel strategy to construct an artificial tobacco mosaic virus (ATMV) that closely mimics the structure of the rod-like tobacco mosaic virus (TMV) is developed. The supramolecular array is self-assembled from small, repeated subunits of tailor-made capsid-mimicking dendrons onto RGD-modified single-walled carbon nanotube to construct the ATMVs with high structural stability. The ATMVs are tactfully designed with shielding, targeting, and arming approaches, including shielding the viruses against premature elimination, selectively targeting tumor tissue, and arming the viruses with oncolytic abilities. The elongated particles are concealed in blood until they arrived at a tumor site, then they induce robust composite oncolytic processes including cytomembrane penetration, endoplasmic reticulum disruption to cause Ca²⁺ release, chemotherapeutic delivery, and photothermal therapy. Excitingly, the ATMVs not only lyse primary infected cells, but permeate adjacent cells for secondary infection, spreading cell-to-cell and continuing to induce lysis even deep in solid tumors. This work inspires a uniquely shaped virus-like agent with tactically optimized oncolytic functions that completely defeated large drug-resistant colon tumor (LoVo/Adr, ≈500 mm³).     

The use of gold markers in immunocytochemical studies of microbiological organisms: a review

Colloidal gold probes have revolutionized electron immunocytochemistry and are now used extensively for microbiological studies. The gold probes can be applied in one of several methods to gain valuable information from the sample. The pre-embedding technique, the post-embedding technique, the immunonegative stain technique, the immunoreplica technique and the immunofreeze-fracture technique, are each described and their applications in microbiology, for diagnosis, for the detection of the site of antigen synthesis in host cells, for vaccine production and for genetic engineering are reported.     

回收污水中肠道病毒方法的改进

介绍了一种城市污水中肠道病毒的浓集方法:病毒浓集前在污水中加入带阳电荷的物质聚氯化铝,30mg/L的聚氯化铝可使f2噬菌体回收率达到(92.06±8.65)%,pH值为6.5时f2回收率达(92.15±6.02)%,温度对回收率没有影响。该方法不仅对病毒的回收率高(>80%),且浓集污水量较大(20L)、效果稳定。     

Inactivation of particle-associated viral surrogates by ultraviolet light

This study investigated whether colloid-sized particles can enmesh and protect viruses from 254-nm ultraviolet (UV) light and sought to determine the particle characteristics (e.g. size, chemical composition) that are most relevant in causing a protective effect. Two viral surrogates (MS2 coliphage and bacteriophage T4), three types of particles (kaolin clay, humic acid powder, and activated sludge), two coagulants (alum and ferric chloride), two filtration conditions (none and 0.45 microm), and two UV doses (40 and 80 mJ/cm2 for MS2 coliphage; 2 and 7 mJ/cm2 for bacteriophage T4) were considered in a series of bench-scale UV collimated beam experiments. Transmission electron microscopy was used to qualitatively confirm the phage particle-association after coagulation. Humic acid and activated sludge floc particles shielded both viral surrogates to a statistically significant degree (with >99% confidence) relative to particle-free control conditions, while the kaolin clay particles provided no significant protection. The results of the study suggest that particles <2 microm in diameter are large enough to protect viruses from UV light and that particulate chemical composition (e.g. UV-absorbing organic content) may be a critical factor in the survival of particle-associated viruses during UV disinfection.