Home About us Contact
|
Home About us Contact | ||
|
|
||
Intricate Interactions (intricate + interaction)
Selected AbstractsMicrobial interactions and differential protein expression in Staphylococcus aureus ,Candida albicans dual-species biofilmsFEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 3 2010Brian M. Peters Abstract The fungal species Candida albicans and the bacterial species Staphylococcus aureus are responsible for a majority of hospital-acquired infections and often coinfect critically ill patients as complicating polymicrobial biofilms. To investigate biofilm structure during polymicrobial growth, dual-species biofilms were imaged with confocal scanning laser microscopy. Analyses revealed a unique biofilm architecture where S. aureus commonly associated with the hyphal elements of C. albicans. This physical interaction may provide staphylococci with an invasion strategy because candidal hyphae can penetrate through epithelial layers. To further understand the molecular mechanisms possibly responsible for previously demonstrated amplified virulence during coinfection, protein expression studies were undertaken. Differential in-gel electrophoresis identified a total of 27 proteins to be significantly differentially produced by these organisms during coculture biofilm growth. Among the upregulated staphylococcal proteins was l -lactate dehydrogenase 1, which confers resistance to host-derived oxidative stressors. Among the downregulated proteins was the global transcriptional repressor of virulence factors, CodY. These findings demonstrate that the hyphae-mediated enhanced pathogenesis of S. aureus may not only be due to physical interactions but can also be attributed to the differential regulation of specific virulence factors induced during polymicrobial growth. Further characterization of the intricate interaction between these pathogens at the molecular level is warranted, as it may aid in the design of novel therapeutic strategies aimed at combating fungal,bacterial polymicrobial infection. [source] Developmental expression and biochemical properties of a ,-1,4-endoglucanase family in the soybean cyst nematode, Heterodera glycinesMOLECULAR PLANT PATHOLOGY, Issue 2 2004Bingli Gao SUMMARY The soybean cyst nematode, Heterodera glycines, produces ,-1,4-endoglucanases (cellulases) that are secreted during infection of soybean. The gene structures of three, hg-eng-4, hg-eng-5 and hg-eng-6, of the six ,-1,4-endoglucanase genes, all family 5 glycosyl hydrolases previously identified from H. glycines, are presented here. Furthermore, we present the detailed expression analyses of ,-1,4-endoglucanase genes as well as the biochemical properties of four H. glycines endoglucanase enzymes. Two of the endoglucanases, HG-ENG-5 and HG-ENG-6, differed significantly in their amino acid sequence of the catalytic domains and their gene structure from that of the other four ,-1,4-endoglucanases. Quantitative real-time RT-PCR revealed distinct developmental expression differences among the hg-eng family members during the early stages of parasitism and relatively low expression levels in late parasitic stages, with the exception of the adult male stage for some eng genes. Recombinant HG-ENGs degraded carboxymethylcellulose and optimum enzyme activity ranged from pH 5.5 for HG-ENG-5 to pH 8 for HG-ENG-6. EDTA, Ca2+, Co2+, Mg2+ and Fe2+ did not affect enzyme activity of any ENG protein, whereas Zn2+, Cu2+ and Mn2+ inhibited enzyme activity from 23% to 73% in some cases. In tests with 12 different polysaccharide substrates, enzyme activity was restricted to ,-1,4 linkages with all ENG proteins tested. Only HG-ENG-5 and HG-ENG-6 had relatively high activity on xylan and slightly degraded microcrystalline cellulose. Together, these data reveal distinct differences in expression and biochemistry of cyst nematode parasitism genes and proteins, respectively, and cast light on the intricate interactions between a parasitic animal and its plant host. [source] Low-energy helium,neon laser induces melanocyte proliferation via interaction with type IV collagen: visible light as a therapeutic option for vitiligoBRITISH JOURNAL OF DERMATOLOGY, Issue 2 2009C-C.E. Lan Summary Background, The treatment of vitiligo remains a challenge for clinical dermatologists. We have previously shown that the helium,neon laser (He,Ne laser, 632·8 nm) is a therapeutic option for treatment of this depigmentary disorder. Objectives, Addressing the intricate interactions between melanocytes, the most important cellular component in the repigmentation scheme of vitiligo, and their innate extracellular matrix collagen type IV, the current study aimed to elucidate the effects of the He,Ne laser on melanocytes. Methods, Cultured melanocytes were irradiated with the He,Ne laser. Relevant biological parameters including cell attachment, locomotion and growth were evaluated. In addition, the potentially involved molecular pathways were also determined. Results, Our results show that in addition to suppressing mobility but increasing attachment to type IV collagen, the He,Ne laser stimulates melanocyte proliferation through enhanced ,2,1 integrin expression. The expression of phosphorylated cyclic-AMP response element binding protein (CREB), an important regulator of melanocyte growth, was also upregulated by He,Ne laser treatment. Using a specific mitochondrial uncoupling agent [carbonyl cyanide m-chlorophenyl-hydrazone (CCCP)], the proliferative effect of the He,Ne laser on melanocytes was abolished and suppression of melanocyte growth was noted. Conclusions, In summary, we have demonstrated that the He,Ne laser imparts a growth stimulatory effect on functional melanocytes via mitochondria-related pathways and proposed that other minor pathways including DNA damage may also be inflicted by laser treatment on irradiated cells. More importantly, we have completed the repigmentation scheme of vitiligo brought about by He,Ne laser light in vitro and provided a solid theoretical basis regarding how the He,Ne laser induces recovery of vitiligo in vivo. [source] Molecular interactions between Plasmodium and its insect vectorsCELLULAR MICROBIOLOGY, Issue 11 2002R. E. Sinden Summary Our understanding of the intricate interactions between the malarial parasite and the mosquito vector is complicated both by the number and diversity of parasite and vector species, and by the experimental inaccessibility of phenomena under investigation. Steady developments in techniques to study the parasite in the mosquito have recently been augmented by methods to culture in their entirety the sporogonic stages of some parasite species. These, together with the new saturation technologies, and genetic transformation of both parasite and vector will permit penetrating studies into an exciting and largely unknown area of parasite,host interactions, an understanding of which must result in the development of new intervention strategies. This microreview highlights key areas of current basic molecular interest, and identifies numerous lacunae in our knowledge that must be filled if we are to make rational decisions for future control strategies. It will conclude by trying to explain why in the opinion of this reviewer understanding malaria,mosquito interactions may be critical to our future attempts to limit a disease of growing global importance. [source] | |||||||||||||