Heat-inactivated C. pneumoniae organisms are not atherogenic

We have previously shown that infection with Chlamydia pneumoniae can significantly exacerbate atherosclerotic lesions in LDLR-/- mice concurrently fed a high cholesterol diet in 6 or 9 months. We now report that a period of 4 month was sufficient for demonstrating the C. pneumoniae atherogenicity. However, heat inactivation of C. pneumoniae organisms completely abolished the ability of C. pneumoniae to exacerbate the atherosclerotic lesions, suggesting that viable organism infection may be required for the C. pneumoniae atherogenicity.     

Restriction of Chlamydia pneumoniae replication in human dendritic cell by activation of indoleamine 2,3-dioxygenase

Infection with Chlamydia pneumoniae, a human respiratory pathogen, has been associated with various chronic diseases such as asthma and atherosclerosis, possibly because the pathogen can exist in a persistent form. C. pneumoniae persistently infect DCs in a TNF-α dependent manner. The present study investigated whether C. pneumoniae infection can induce indoleamine 2,3-dioxygenase (IDO) activity in dendritic cells, and whether the restriction of chlamydial growth in the DCs by TNF-α is IDO dependent. Our data indicate that infection of DCs with C. pneumoniae resulted in the induction of IDO expression. Reporting on our use of anti-TNF-α antibody adalimumab and varying concentrations of TNF-α, we further demonstrate that IDO induction following infection of DCs with C. pneumoniae is TNF-α dependent. The anti-chlamydial activity induced by TNF-α and the expression of chlamydial 16S rRNA gene, euo, groEL1, ftsk and tal genes were correlated with induction of IDO. Addition of excess amounts of tryptophan to the DC cultures resulted in abrogation of the TNF-α-mediated chlamydial growth restriction. These findings suggest that infection of DCs by C. pneumoniae induces production of functional IDO, which subsequently causes depletion of tryptophan. This may represent a potential mechanism for DCs to restrict bacterial growth in chlamydial infections.     

Chlamydia pneumoniae infection significantly exacerbates aortic atherosclerosis in an LDLR–/– mouse model within six months

We have previously shown that infection with the C. pneumoniae AR39 strain once monthly for 9 consecutive months significantly exacerbated atherosclerosis in mice with LDL receptor deficiency (LDLR–/–) in the presence of a high cholesterol diet. To further optimize the LDLR–/– mouse model for studying the mechanisms of C. pneumoniae atherogenesis, we have tested a different infection protocol with intranasal inoculation twice monthly for 6 consecutive months in the present study. We found that C. pneumoniae infection for 6 months was sufficient to produce a 130%, significantly greater exacerbation of aortic atherosclerosis in LDLR–/– mice in the presence of a high cholesterol diet. Mice receiving a high cholesterol diet alone displayed a lesion area index of 18.2 ± 6.1 (S.D.) while mice treated with both the high cholesterol diet and C. pneumoniae infection had a lesion area index of 41.8 ± 15.2 (S.D.). However, the chlamydial infection did not significantly alter the mouse serum total cholesterol or the LDL levels induced by the high cholesterol diet. This study not only confirms our previous findings that C. pneumoniae infection can exacerbate aortic atherosclerosis lesion in the LDLR–/– mice, but also further optimizes the LDLR–/– mouse model for future mechanism studies.     

Interactions between Chlamydia pneumoniae and trace elements: a possible link to aortic valve sclerosis

An association between Chlamydia pneumoniae and atherosclerotic cardiovascular diseases has been suggested. However, other factors may interact in the pathogenesis of valve sclerosis. Therefore, trace elements important for C. pneumoniae growth and host defense and markers of C. pneumoniae infection were studied in sclerotic valves and serum. Forty-six patients undergoing surgical valve replacement due to advanced aortic sclerosis were prospectively studied. Valves from 15 forensic cases with no heart valve disease and plasma from 46 healthy volunteers served as controls. C. pneumoniae was detected in 16/46 (34.8 %) sclerotic valves and in 0/15 forensic controls. IgG and IgA antibodies to C. pneumoniae were present in 54.3% and 26.1 % patients, respectively. In the patients’ valves, iron, magnesium, and zinc each correlated to calcium, a marker of the histopathological severity of disease. Patients showed 10- to 70-fold increases of these trace elements in valves and an increased copper/zinc ratio in serum. In a majority of aortic sclerosis patients, one of several markers of C. pneumoniae infection were detected and all patients had a disturbed trace element balance in valves and serum suggestive of active immune process and infection. The pattern of trace element changes was essentially similar regardless of positive makers of C. pneumoniae, suggesting a similar etiopathogenesis in both subgroups. The 20-fold increase in iron, essential for C. pneumoniae growth, in sclerotic valves suggests a new possible link to this infection in aortic sclerosis.     

Dissemination of Chlamydia pneumoniae to the vessel wall in atherosclerosis

Heart disease and stroke are the result of atherosclerotic vascular lesions. It is becoming increasingly clear that an infection may be an important initiating component within the atherogenic process. However, in order for the infection to contribute to atherosclerosis, it must first be capable of disseminating to the vessel wall. Chlamydia pneumoniae is an example of an infectious atherogenic stimulus. The present treatise reviews our knowledge concerning dissemination of infectious agents like C. pneumoniae. Three factors can be identified that modulate the severity of the infection in the vascular wall. First, although all vascular cell types appear to be infected with agents like C. pneumoniae, there are differences in the sensitivity to infection amongst these cell types. Second, the lipid environment is important in defining the effects of C. pneumoniae on atherosclerotic disease. Third, the inflammatory/atherosclerotic interaction is influenced by the specific infectious stimuli employed. The in situ atherogenic effects of C. pneumoniae may be specific to this organism and may not occur with related infectious agents like C. trachomatis. Despite the identification of these three factors, controversy exists surrounding specific characteristics of these effects. This may be the result of a plethora of differing experimental conditions (different labs, different lipids, different cell types or lines, and different C. pneumoniae characteristics (infection, dosage, duration, etc.)). Further study of these important phenomena is clearly warranted in view of the potential importance of infection to the atherosclerotic disease.     

Induction of proinflammatory cytokines in human osteoblastic cells by Chlamydia pneumoniae

Chlamydia pneumoniae is an obligate intracellular Gram-negative bacterium that causes recurrent pharyngitis, pneumonia and chronic inflammation induced by cycles of persistence and productive infection that might also explain the association with chronic diseases. The aim of this study was to determine whether C. pneumoniae can invade and survive within human osteoblasts and whether this infection elicits the secretion of proinflammatory cytokines.Our results demonstrated that C. pneumoniae was able to infect the SaOS-2 osteoblastic cell line and to replicate in the osteoblasts in a time-dependent manner and was associated to an increase in the cell number and cell viability.In addition, infection of the SaOS-2 cell line with C. pneumoniae at MOI of 4 is correlated to a proinflammatory response. Infected osteoblasts produced increased levels of cytokines IL-6, IL-8, IL-17, and IL-23. The production of cytokines increased with subsequent interaction between osteoblasts and monocytes and the maximum levels of cytokines released were detected 72 h after infection with C. pneumoniae. Thus, controlling the release of chemokines, e.g., IL-23, may be a therapeutic strategy for preventing inflammatory bone disease and counteract inflammation and bone destruction.     

Is infection with Chlamydia pneumoniae a causative agent in atherosclerosis?

There is mounting evidence to suggest that Chlamydia pneumoniae might play a role in atherosclerosis. Serological studies and detection of the microorganism in atheromatous lesions were the first indications of an association between C. pneumoniae and the disease. Studies suggest that anti-chlamydial chemotherapy has a favorable effect on cardiovascular disease in humans. Moreover, infection of animals with C. pneumoniae induces inflammatory changes in the aorta that are suggestive of atherosclerosis and accelerates the progression of existing atherosclerotic lesions. If the pathogenic role of C. pneumoniae in atherosclerosis is defined more conclusively by future studies, the development of preventive or therapeutic measures against infection might provide an effective strategy to reduce the risk of atherosclerosis.     

耐碳青霉烯类肺炎克雷伯菌对C57BL/6小鼠肺部菌群的扰动

【背景】肺部菌群与宿主健康和呼吸道疾病密切相关,耐碳青霉烯类肺炎克雷伯菌(carbapenem-resistantKlebsiella pneumonia,CRKP)是临床常见的条件致病菌,感染后对肺部菌群的影响尚不清楚。【目的】探究耐碳青霉烯类肺炎克雷伯杆菌CRKP2对C57BL/6小鼠肺部菌群的扰动。【方法】将C57BL/6小鼠随机分为3组,分别用CRKP2、碳青霉烯类敏感肺炎克雷伯菌KP2044和无菌PBS溶液滴鼻,利用16S rRNA基因的高通量测序技术分析肺部菌群结构。【结果】与健康小鼠相比,菌株KP2044和CRKP2感染后小鼠肺部菌群α多样性和β多样性均显著改变,变形菌门相对丰度显著增加,乳酸杆菌属相对丰度明显下降。与KP2044相比,CRKP2生物膜形成能力较弱,感染后小鼠死亡率较低,对肺部菌群的扰动较小。【结论】虽然肺炎克雷伯菌是条件致病菌,但高剂量耐碳青霉烯类肺炎克雷伯菌CRKP2仍对健康小鼠肺部菌群造成显著影响;尽管菌株CRKP2具有多重耐药性,但与菌株KP2044相比对肺部菌群的扰动较小,因此推测KP菌株感染对肺部菌群的扰动程度可能与菌株毒力有关。     

The reactivity of cytochrome c with soft ligands

The spectral changes caused by binding soft ligands to the cytochrome c iron and their correlation to ligand affinities support the hypothesis that the iron—methionine sulfur bond of this heme protein is enhanced by delocalization of the metal l₂, electrons into the empty 3d orbitals of the ligand atom. These findings also explain the unique spectrum of cytochrome c in the far red.     

Chlamydia and mycoplasma infections during pregnancy and their relationships to orofacial cleft

Serum antibodies to Mycoplasma pneumoniae and Chlamydia trachomatis have been studied in a group of newborns with orofacial cleft (OC) and their mothers (n = 59) as compared to a control group of healthy newborns and their mothers (n = 40) assayed by ELISA and Western blot analysis. In the first group, IgG antibodies to M. pneumoniae were found by ELISA in 12 newborns with OC and 22 mothers, while IgA antibodies were detected only in 5 and 11 cases, respectively. IgM antibodies indicating an acute infection were found in 2 mothers only. IgG antibodies to C. trachomatis were found in 2 newborns with OC and 4 mothers. In the control group, IgG antibodies to M. pneumoniae were found in 3 newborns and 7 mothers. IgG antibodies to C trachomatis were observed in 1 newborn and 1 mother, while IgM antibodies to C trachomatis were present in 1 mother only. Immunoblot analysis revealed in newborns with OC and their mothers C. trachomatis-specific bands associated with MOMP 1, 29 kDa, 45 kDa, and heat shock proteins (HSP) 60 and 70. Based on these results we suggest that the risk associated with the exposure to M. pneumoniae and/or C. trachomatis is so far unknown and further study is needed for its elucidation.     

<Emphasis Type="Italic">Colletotrichum gloeosporioides</Emphasis> can Overgrow <Emphasis Type="Italic">Colletotrichum kahawae</Emphasis> on Green Coffee Berries First Inoculated with <Emphasis Type="Italic">C. kahawae</Emphasis>

Colletotrichum gloeosporioides is a weak pathogen of coffee that infects ripe berries at dark red stage causing necrotic lesions, but only penetrates up to the second superficial layers of the pericarp at the rose and pink stages. C. kahawae, the causal agent of coffee berry disease (CBD) and responsible for 70–80% of crop loss, infects berries at any stage of development. When green berries are first inoculated with C. kahawae and then at 2, 72 or 96 h later with C. gloeosporioides, the necrotic lesions were significantly larger than in the controls, and were much more evident when the berries were incubated at the optimum growth temperature of 28 °C for C. gloeosporioides. Isolations from the lesions induced by the first inoculations with C. kahawae followed by inoculation with C. gloeosporioides revealed that all or most of the time the recovered isolates of the latter. Thus, C. gloeosporioides can overwhelm C. kahawae under conditions of higher environmental temperature and humidity and may enhance the CBD infection process under field conditions.     

Characteristics of oviposition behaviour of the pollen beetle, Meligethes aeneus on four different host plants

Oviposition behaviour of Meligethes aeneus F. (Coleoptera: Nitidulidae) is characterised and quantified on four different plant species. Six behavioural components are identified: W—walking, WA—walking with abdomen on surface, R—resting, B—biting, AOH—placing abdomen over the bite hole and OVI—oviposition. Comparison of host acceptance behaviours on Brassica napus L., Brassica juncea (L.) Czern, Brassica nigra (L.) Koch and Sinapis alba L. showed that S. alba was accepted as a host only after a long exposure to the plant. Behaviour on the Brassica species was similar, however on B. nigra beetles spent a high proportion of time actually ovipositing. We conclude that important cues for oviposition are located both on the bud surface and inside the bud.     

Differences in the envelope proteins ofChlamydia pneumoniae,Chlamydia trachomatis,andChlamydia psittaci shown by two-dimensional gel electrophoresis

Analysis by two-dimensional gel electrophoresis of theN-laurylsarkosinate(Sarkosyl)-insoluble envelope complexes ofl-^[35]S-cysteine-iabeled elementary bodies ofChlamydia pneumoniae strain IOL-207,Chlamydia trachomatis serovar LGV2, D, and F, andChlamydia psittaci strain 6BC showed differences in the molecular charges of chlamydial outer membrane proteins. The apparent isoelectric point (pI) of the major outer membrane protein ofC. pneumoniae strain IOL-207 was 6.4, whereas the pI of the major outer membrane protein of theC. trachomatis andC. psittaci strains differed little from one another, ranging from 5.3 to 5.5. The 60-kDa cysteinerich protein ofC. pneumoniae was the only 60-kDa chlamydial protein with a pI value (5.9) more acidic than that of the corresponding major outer membrane protein. As a general rule, the charges of both the 60-kDa and the lowmolecular-mass (12–15 kDa) cysteine-rich proteins were widely variable, depending on the strain. However, in cach individual strain, the variation of the charge of the 60-kDa protein had a compensatory change in the lowmolecular-mass cysteine-rich protein.     

肺炎链球菌与宿主炎症小体的相互作用机制

肺炎链球菌(Streptococcus pneumoniae)是一种定植于上呼吸道的革兰阳性胞外菌,是导致侵袭性肺炎的主要原因,所致疾病具有较高的发病率和死亡率。炎症小体(inflammasome)是胞浆内重要的蛋白复合体,在先天免疫应答过程中起着重要作用。大量研究表明,肺炎链球菌感染可诱导宿主炎症小体的激活、半胱天冬酶1的活化和促炎性细胞因子的分泌。在长期选择压力的作用下,肺炎链球菌的部分突变菌株可以逃避炎症小体的识别。本文就肺炎链球菌感染过程中炎症小体的激活、炎症小体在抗肺炎链球菌过程中的作用以及肺炎链球菌逃避宿主炎症小体识别的机制三方面对肺炎链球菌与炎症小体之间相互作用的研究进展进行综述。     

DNA sequence analysis of the lamB gene from Klebsiella pneumoniae: implications for the topology and the pore functions in maltoporin.

Summary We have determined the sequence of the lamB gene from Klebsiella pneumoniae. It encodes the precursor to the LamB protein, a 429 amino acid polypeptide with maltoporin function. Comparison with the Escherichia coli LamB protein reveals a high degree of homology, with 325 residues strictly identical. The N-terminal third of the protein is the most conserved part of the molecule (1 change in the signal sequence, and 13 changes up to residue 146 of the mature protein). Differences between the two mature proteins are clustered mainly in six regions comprising residues 145–167, 173–187, 197–226, 237–300, 311–329, and 367–387 (K. pneumoniae LamB sequence). The most important changes were found in regions predicted by the two-dimensional model of LamB folding to form loops on the cell surface. In vivo maltose and maltodextrin transport properties of E. coli K 12 and K. pneumoniae strains were identical. However, none of the E. coli K12 LamB-specific phages was able to plaque onto K. pneumoniae. Native K. pneumoniae LamB protein forms highly stable trimers. The protein could be purified by affinity chromatography on starch-Sepharose as efficiently as the E. coli K12 LamB protein, indicating a conservation of the binding site for dextrins. However, none of the monoclonal antibodies directed against native E. coli K12 LamB protein recognized native purified K. pneumoniae LamB protein. These data indicate that most of the variability occurs within exposed regions of the protein and provide additional support for the proposed model of LamB folding. The fact that the N-terminal third of the protein is highly conserved is in agreement with the idea that it is part of, or constitutes, the pore domain located within the transmembranous channel and that it is not accessible from the cell surface.     

Changes in the cell wall of Clostridium species following passage in animals

Morphological changes in clostridial isolates after animal passage with other flora in mixed infections were studied by utilizing a subcutaneous abscess model in mice. We used 26 isolates of 7 clostridial species, and one isolate each of Bacteroides fragilis and Klebsiella pneumoniae. Abscesses were induced by all 7 Clostridium perfringens and 3 Clostridium butyricum isolates and by some of the other isolates. A thick granular wall prior to animal inoculation was shown only in C. perfringens, C. butyricum, and C. difficile. This structure was observed in other clostridia only following their animal passage alone or when co-inoculated with K. pneumoniae or B. fragilis.     

噬菌体治疗肺炎克雷伯菌感染的研究进展

肺炎克雷伯菌是肠杆菌科家族中的一员,在各种环境中广泛存在,可导致诸如奶牛乳房炎在内的多种动物疫病,引起人类的肺炎、尿路感染、菌血症、伤口性感染和化脓性脓肿在内的多种临床感染。该菌对抗生素的耐受日趋严重,而且高毒力菌株不断出现,给该菌的防控带来了巨大挑战。噬菌体是一种裂解细菌的病毒,因其具有治疗耐药细菌感染的潜力而备受关注,世界各地均有使用噬菌体成功治疗耐药细菌感染的案例。本文基于国内外对肺炎克雷伯菌及其噬菌体的研究数据,综述了肺炎克雷伯菌的流行病学调查情况和噬菌体在治疗肺炎克雷伯菌感染方面的应用,以期为基于肺炎克雷伯菌噬菌体的抗菌研究和临床应用提供参考。     

肺炎克雷伯菌噬菌体解聚酶的研究进展

肺炎克雷伯菌(Klebsiella pneumoniae)是在临床引起多种感染的常见条件致病菌之一。多重耐药肺炎克雷伯菌株的出现,给防控细菌感染带来了巨大阻力。肺炎克雷伯菌噬菌体编码的解聚酶是一种稳定性高、特异性强的生物酶,具有分解细菌胞外多糖、限制细菌生长等多种功能。解聚酶可为防控肺炎克雷伯菌感染提供新思路,在抗菌应用中具有广阔前景。本文就肺炎克雷伯菌噬菌体解聚酶的研究进展进行综述。     

Structures of sugar-binding peptides of <Emphasis Type="Italic">Galega orientalis</Emphasis> and <Emphasis Type="Italic">G. officinalis</Emphasis> lectins determine the choice of partner in rhizobium—Legume symbiosis

RAPD and RFEL analyses revealed appreciable genetic heterogeneity of Rhizobium galegae bv. officinalis and R. galegae bv. orientalis, which are nitrogen-fixing symbiosis partners of Galega officinalis and G. orientalis, respectively, and do not form a single cross-inoculation group. Comparison of nucleotide and amino acid sequences for their lectins revealed relatively high general homology, testifying again to their close phylogenetic relationships. Yet the lectin region of the carbohydrate-binding peptide (CBP) proved to differ considerably, being TYCNPGWDPRDR in G. orientalis and TFYNEEWDLVIKDEH in G. officinalis. Conserved positions in the CBP were observed for amino acid residues involved in binding Ca²⁺ and Mn²⁺ and stabilizing the spatial structure of the carbohydrate-binding pocket. These findings confirm the role in Rhizobium— legume symbiosis for lectins and especially for their carbohydrate-binding domains.Translated from Molekulyarnaya Biologiya, Vol. 39, No. 1, 2005, pp. 103–111.Original Russian Text Copyright © 2005 by Baimiev, Gubaidullin, Chemeris, Vakhitov.