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81.
人体内定植着数目庞大、结构复杂的细菌及真菌等微生物群,它们之间存在复杂的相互作用。既往研究主要集中于细菌或真菌的某个单一物种,但最近研究表明,细菌与真菌之间的相互作用对更好地理解体内的微生态系统至关重要。白假丝酵母(又称白念珠菌)是人备体中最常见的机会性致病真菌,通常被认为是人类正常菌群的一部分。白念珠菌与细菌的相互作用近年来备受关注,其协同和拮抗作用有助于维持不同物种间复杂的平衡关系。了解白念珠菌与细菌的相互作用,不仅可加深对微生物致病机制的理解,还可为预防和治疗白念珠菌或细菌感染及新型抗菌药物研发提供新途径。本文就白念珠菌与细菌共存时的相互作用机制及其对人类健康、疾病的影响进行综述,从而为控制念珠菌或细菌感染提供新的策略。 相似文献
82.
83.
Laboulbeniopsis termitarius, an ectoparasitic fungus of termites, was harvested from the body surface of Reticulitermes speratus (Isoptera: Rhinotermitidae), collected in Uji, Kyoto Prefecture, Japan. This is the first record of this fungus from Japan. Three to eighteen termite workers from 500 individuals were infected among the eight colonies investigated. From our results, several hundred termite are required for the survey of this ectoparasitic fungi in Japan. The temperature effect on the relationship between the infection rate and the host activity was discussed. 相似文献
84.
目的:分析妊娠期未足月胎膜早破孕妇发生孕周及病因,为临床处治提供指导。方法:103例未足月胎膜早破孕妇患者按孕周分为两组,对他们的临床资料进行回顾性研究。结果:2组在患者平均年龄及反应感染的血指标没有明显区别,均未提示入院时存在感染。103例PPROM患者破膜孕周主要发生在孕32-36+6周,双胎及生殖系统微生物感染为破膜的主要原因,终止妊娠原因主要为羊水过少。宫颈管微生物培养菌主要为GBS,其余可见的有白色念珠菌,表皮葡萄球菌,弓形虫,及其他厌氧菌。结论:生殖系统炎症尤其是GBS感染是导致未足月胎膜早破的重要原因;双胎也是导致PPROM发尤其是生的高危因素,减少胎膜早破,也有助于降低剖宫产率,改善胎儿结局。 相似文献
85.
Zhou J Tun TN Hong SH Mercer-Chalmers JD Laabei M Young AE Jenkins AT 《Biosensors & bioelectronics》2011,30(1):67-72
A new methodology for detecting the microbiological state of a wound dressing in terms of its colonization with pathogenic bacteria such as Staphylococcus aureus or Pseudomonas aeruginosa has been developed. Here we report how stabilized lipid vesicles containing self-quenched carboxyfluorescein dye are sensitive to lysis only by toxins/virulence factors from P. aeruginosa and S. aureus but not by a non-toxic Escherichia coli species. The development of the stabilized vesicles is discussed and their response to detergent (triton), bacterial toxin (α-hemolysin) and lipases (phospholipase A2). Finally, fabrics with stabilized vesicles attached via plasma deposited maleic anhydride coupling are shown visibly responding to S. aureus (MSSA 476) and P. aeruginosa (PAO1) but not E. coli DH5α in a prototype dressing. 相似文献
86.
Fusarium graminearum is one of the main causal agents of Fusarium Ear Blight on wheat. How the pathogen colonises the entire ear is not known. There is controversy over whether this mycotoxin producing pathogenic fungus invades wheat floral tissue using a necrotrophic or another mode of nutrition. A detailed microscopic investigation has revealed how wild-type fungal hyphae, of the sequenced strain PH-1, colonised susceptible wheat ears and spread from spikelet to spikelet. At the advancing infection front, colonisation of the host cortex occurred ahead of any vascular colonisation and the hyphae adapted to the available intercellular space between host cells. Intercellular hyphae then became abundant and host cells lost their entire cellular contents just prior to intracellular colonisation. No host cells died ahead of the infection. However, while these deep cortex infections progressed, just below the surface the highly photosynthetic chlorenchyma cells were observed to have died prior to colonisation. Behind the infection front, hyphae were abundant in the vasculature and the cortex, often growing through the pit fields of thick walled cells. This high level of inter- and intracellular fungal colonisation resulted in the collapse of the non-lignified cell-types. In this middle zone of infection, hyphal diameters were considerably enlarged. Far behind the infection front inter- and intracellular hyphae were devoid of contents and had often collapsed. At later stages of infection, the pathogen switched from predominately vertical to lateral growth and accumulated below the surface of the rachis. Here the lignified host cell walls became heavily degraded and hyphae ruptured the epidermis and produced an aerial mycelium. 相似文献
87.
Silva MT do Vale A dos Santos NM 《Apoptosis : an international journal on programmed cell death》2008,13(4):463-482
In metazoans apoptosis is a major physiological process of cell elimination during development and in tissue homeostasis and
can be involved in pathological situations. In vitro, apoptosis proceeds through an execution phase during which cell dismantling
is initiated, with or without fragmentation into apoptotic bodies, but with maintenance of a near-to-intact cytoplasmic membrane,
followed by a transition to a necrotic cell elimination traditionally called “secondary necrosis”. Secondary necrosis involves
activation of self-hydrolytic enzymes, and swelling of the cell or of the apoptotic bodies, generalized and irreparable damage
to the cytoplasmic membrane, and culminates with cell disruption. In vivo, under normal conditions, the elimination of apoptosing
cells or apoptotic bodies is by removal through engulfment by scavengers prompted by the exposure of engulfment signals during
the execution phase of apoptosis; if this removal fails progression to secondary necrosis ensues as in the in vitro situation.
In vivo secondary necrosis occurs when massive apoptosis overwhelms the available scavenging capacity, or when the scavenger
mechanism is directly impaired, and may result in leakage of the cell contents with induction of tissue injury and inflammatory
and autoimmune responses. Several disorders where secondary necrosis has been implicated as a pathogenic mechanism will be
reviewed. 相似文献
88.
The Gram-positive bacterium Clavibacter michiganensis subsp. sepedonicus is the causal agent of bacterial wilt and ring rot of potato. So far, only two proteins have been shown to be essential for
virulence, namely a plasmid-encoded cellulase CelA and a hypersensitive response-inducing protein. We have examined the relative
expression of CelA and eight putative virulence factors during infection of potato and in liquid culture, using quantitative
real-time PCR. The examined putative virulence genes were celB, a cellulase-encoding gene and genes encoding a pectate lyase, a xylanase and five homologues of the Clavibacter michiganensis subsp. michiganensis pathogenicity factor Pat-1 thought to encode a serine protease. Six of the nine assayed genes were up-regulated during infection
of potato, including celA, celB, the xylanase gene, and two of the pat genes. The pectate lyase gene showed only slightly elevated expression, whereas three of the five examined pat genes were down-regulated during infection in potato. Interestingly, the two up-regulated pat genes showed a noticeable sequence
difference compared to the three down-regulated pat genes. These results reveal several new proteins that are likely to be
involved in Clavibacter michiganensis subsp. sepedonicus pathogenicity. 相似文献
89.
Côtes K Bakala N'goma JC Dhouib R Douchet I Maurin D Carrière F Canaan S 《Applied microbiology and biotechnology》2008,78(5):741-749
Mycobacterium tuberculosis is a bacterial pathogen that can persist for decades in an infected patient without causing a disease. In vivo, the tubercle
bacillus present in the lungs store triacylglycerols in inclusion bodies. The same process can be observed in vitro when the
bacteria infect adipose tissues. Indeed, before entering in the dormant state, bacteria accumulate lipids originating from
the host cell membrane degradation and from de novo synthesis. During the reactivation phase, these lipids are hydrolysed
and the infection process occurs. The degradation of both extra and intracellular lipids can be directly related to the presence
of lipolytic enzymes in mycobacteria, which have been ignored during a long period particularly due to the difficulties to
obtain a high expression level of these enzymes in M. tuberculosis. The completion of the M. tuberculosis genome offered new opportunity to this kind of study. The aim of this review is to focus on the recent results obtained in
the field of mycobacterium lipolytic enzymes and although no experimental proof has been shown in vivo, it is tempting to
speculate that these enzymes could be involved in the virulence and pathogenicity processes. 相似文献
90.
Wolbachia is a ubiquitous, Gram-negative, vertically transmitted, alpha-proteobacterium that causes an array of reproductive abnormalities
including cytoplasmic incompatibility, feminization of genetic males, parthenogenesis in a number of insect species, among
others. Wolbachia is now being exploited as an agent for pest and vector control. Previous surveys indicated that it is commonly seen in 16–76%
of arthropods. In this paper, using polymerase chain reaction assay based on specific amplification of the ftsZ-A and-B supergroup Wolbachia gene fragments, we found that 30% of insects and pests screened were positive for Wolbachia. Among them 66.7% harbour double Wolbachia infection, while 33.3% harbour single Wolbachia infection. These results indicate widespread infection with both double and single Wolbachia, and provide a wealth of information to exploit this endobacterium for the management of pests and vectors. 相似文献