Table of Content

28 August 2012, Volume 7 Issue 4

Previous Issue    Next Issue

The effect of extra copies of sho 1 or pbs 2 gene on the adaptive ability of Aspergillus fumigatus to several stresses

MA Dong-mei, JI Ya-juan, YANG Fang, LIU Wei, WAN Zhe, LI Ruo-yu

2012, (4):  193-198. 

Asbtract ( 1765 )   PDF (976KB) ( 1130 )  

References | Related Articles | Metrics

Objective To explore the role of extra copies of sho 1 or pbs 2 in resistance to hyperosmotic stress,oxidative stress, cell wall stress and alkaline pH stress in A. fumigatus.Methods The reconstructed plasmid harboring a sho 1 gene or a pbs 2 gene were transformed into A. fumigatus by using protoplast transformation method and the resulting strains were designated MCsho1 or MCpbs2. RT-PCR was used to detect the expression levels of sho 1 in MCsho1 and pbs 2 in MCpbs2 strains. Then strains harboring extra copies as well as sho 1 and pbs 2 deleted mutants were treated with NaCl, H₂O₂, Congo red and alkaline pH stresses and the resistance phenotypes were observed.Results Mutants harboring extra copies of sho 1 or pbs 2 showed higher expression levels of sho 1 or pbs 2 respectively. Extra copies of sho 1 or pbs 2 conferred resistance to NaCl (1 mol/L), H₂O₂ (5 mmol/L), Congo red (400 mg/L)or alkaline pH (10.0)stress.sho 1 and pbs 2 deleted mutants showed higher sensitivity to NaCl (1 mol/L),H₂O₂ (5 mmol/L)and alkaline pH (10.0)stress than the wild strain. △pbs 2 deleted mutant showed similar sensitivity to Congo red (400mg/L) compared to the wild strain.Conclusion Extra copies of sho 1 or pbs 2 conferred resistance to hyperosmotic stress, oxidative stress, cell wall stress and alkaline pH stress in A. fumigatus.

Construction of knockout plasmid of IPF14744 gene of Candida albicans

TAN Hong-yue, LI Ping, HU Chan, ZHU Hong-mei, GU Jun, WEN Hai

2012, (4):  199-202. 

Asbtract ( 1842 )   PDF (866KB) ( 1302 )  

References | Related Articles | Metrics

Objective To construct the plasmid for IPF 14744 knockout in Candida albicans.Methods Up and down streams of IPF 14744 gene ORF were amplified and inserted into the p5921 plasmid by restriction enzymes.Results The knockout plasmid pUC-14744-URA3 was successfully constructed.Conclusions The knockout plasmid is helpful for homologous recombination knockout of IPF 14744 in Candida albicans.

In vitro activity of chitosan against Candida albicans biofilm

TIAN Yuan, LIAO Wan-qing, LI Xiu-li

2012, (4):  203-206,218. 

Asbtract ( 2057 )   PDF (1485KB) ( 759 )  

References | Related Articles | Metrics

Objective To investigate inhibitory effect of chitosan on Candida albicans biofilm, and to discuss the possible mechanism.Methods XTT reduction assay was used to investigate the influence of different concentrations of chitosan on Candiia albicans biofilm formation and cell adherence.Microscopic examination was conducted to assess the effect of chitosan on morphogenesis of Candida albicans biofilm.The mRNA expressions of CDC35,PDE2,EFG1 and HWP1 were measured by realtime RT-PCR with different concentrations of chitosan.Results The inhibition rates of chitosan against Candida albicans biofilm formation were (19.6±1.2)% by 0.02 mg/mL and (96.96±0.6)% by 0.32 mg/mL.Chitosan (0.16 mg/mL) inhibited different stages of biofilm,with (78.6±0.5)%,(54.4±0.9)% and (41.1±1.1)% inhibition rates when cells was treated for 0 h,12 h and 48 h,respectively.Chitosan from 0.02 mg/mL to 0.32 mg/mL showed distinct inhibitive effect on adhesion to Candida albicans cultured for 30 min,60 min,90 min and 120 min (P<0.05).The mRNA expression levels of CDC35,EFG1 and HWP1 were decreased in Chitosan treated cells, while the PDE mRNA level was increased.Conclusion Chitosan may inhibit the Candida albicans biofilm formation through regulating Ras signaling pathway and cell adherence.

Diagnostic value of (1-3) -β-D-glucan for invasive fungal infection:a clinical research

LIU Chun-yu, WANG Hong, REN Ai-min, DU Kun, HU Lan, LI Shi-rong, WEN Yan, ZHANG Shu-wen

2012, (4):  207-210. 

Asbtract ( 1685 )   PDF (820KB) ( 909 )  

References | Related Articles | Metrics

Objective To assess the clinical application of blood plasma (1-3)-β-D-glucan measurement in diagnosis of deep fungal infection.Methods One hundred and seventy-four patients were registered in Beijing Friendship hospital during 03-11,2009.According to Invasive Fungual Infection (IFI) guideline, serum (1-3) -β-D-glucan was examined routinely using Microbiology Kinetic Rapid Reader MB-80.Results The serum (1-3) -β-D-glucan value detected in deep fungal infection group was (153.4±37.0) pg/mL, whereas (54.6±8.6) pg/mL of serum (1-3) -β-D-glucan were detected in non-infection group. There was significant difference between the two groups (t=3.4,P<0.01).Applying 20 pg/mL of serum (1-3)-β-D-glucan as threshold value for diagnosis of deep fungal infection, the accuracy rate, sensitivity, specificity, positive predictive value, negative predictive values were 70.1%,87.5%,61.9%,52.1%,91.2%, respectively.The values of serum (1-3)-β-D-glucan showed no statistically significant difference among the groups (P>0.05) of confirmed cases (20.0±15.8 pg/mL), clinically diagnosed cases (181.1±74.1 pg/mL), and suspected cases (145.4±39.6 pg/mL).Conclusion With high sensitivity and specificity, serum (1-3)-β-D-glucan (>20 pg/mL) can be seen as diagnostic threshold value of deep fungal infection.

The survey of oropharyngeal and nasal fungal isolation rate in HIV-infected patients

HUANG Ling-li, ZHANG Wen-hong, LI Li, ZHANG Qiang-qiang

2012, (4):  211-213. 

Asbtract ( 1690 )   PDF (777KB) ( 795 )  

References | Related Articles | Metrics

Objective To investigate fungal positive isolating rate of oropharynx and nasal cavity of HIV infected patients.Methods Collected mucous membrane secretions of pharyngo-oral cavity ulcer, leukoplakia, angular cheilitis, pharynx-buccal region and concha nasalis inferior or middle nasal meatus of nasal cavity were inoculated into 1 mL SDA liquid medium directly. The centrifugated depositions were observed directly under microscopy and inoculated into CHROM agar in 37℃ for 48 h. The isolate might be inoculated into Czapek agar medium in 25℃ for 1 week if it was filamentous, then identified into species by colony morphology and structures observed under microscopy.Results Among 94 HIV infected patients, there were 62 patients (66%) who were positive for fungal culture of pharyngo-oral cavity and 65 strains were isolated. While for nasal cavity, 48 patients (51%) were positive and 57 strains were obtained.Conclusions HIV infected patients were immunocompromised and easy to get secondary fungus infection. The high fungal colonization rate in oropharynx and nasal cavity were precursory symptom of invasive fungal infection. The isolation ratio of Candida albicans were the highest, 61% and 33% for oropharynx and nasal cavity repectively.

Invasive pulmonary aspergillosis in autoimmune bullous diseases patients:three cases report

YU Jin, MU Xiang-dong, WAN Zhe, QUE Cheng-li, LI Ruo-yu

2012, (4):  214-218. 

Asbtract ( 1539 )   PDF (1093KB) ( 832 )  

References | Related Articles | Metrics

Objective To study the diagnosis and treatment of invasive pulmonary aspergillosis in autoimmune bullous diseases patients under long-term glucocorticoids treatment by retrospectively reviewing three cases.Methods Report three cases of autoimmune bullous diseases with invasive pulmonary aspergillosis. KOH smear and culture, antigen detection, chest CT scan and histopathologic test were used to diagnose the patients. The organisms isolated from the sputum were identified as Aspergillus fumigatus, A. flavus and Emericella echinulata by morphological and molecular methods.Results Three cases were diagnosed as invasive pulmonary aspergillosis. The patients were cured with voriconazole treatment and other antifungal agents.Conclusion Autoimmune bullous diseases patients should be watched out emerging invasive apergillosis during long-term glucocorticoids therapy. Combined laboratory examinations will be helpful in early diagnosis and increasing efficacy.

Application of lateral ventricular drainage in early treatment of cryptococcal meningoencephalitis

DU Lin, YANG Ya-li, HUANG Chen, LEI Wen-zhi, LIAO Wan-qing, WEN Hai, CHEN Jiang-han

2012, (4):  219-222. 

Asbtract ( 2066 )   PDF (855KB) ( 1403 )  

References | Related Articles | Metrics

Objective To observe the clinical effect of the lateral ventricular drainage in early treatment of cryptococcal meningoencephalitis,and to investigate its efficacy and safety.Methods Retrospective review and analyse the clinical data of 5 patients who had cryptococcal meningoencephalitis with intracranial hypertension using above treatment.Results In all the 5 patients, clinical symptom alleviated rapidly after early lateral ventricular drainage treatment,and no relapse was complained even after withdraw of lateral ventricular drainage. During the treatment of lateral ventricular drainage, no complication of lateral ventricular drainage,such intracranial infection was observed,and combined the antifungal therapy,the early microbiological test results improved.Conclusion Lateral ventricular drainage is an effective, rapid and safe method to ameliorate headache in the early treatment of cryptococcal meningoencephalitis.

The treatment of multidrug-resistant Sporothrix schenckii infection:a case report

HU Su-quan, GUO Ning-ru, CAI Qing, SONG Xue-dong, LI Xiao-fang, WU Shao-xi

2012, (4):  228-229. 

Asbtract ( 1686 )   PDF (899KB) ( 869 )  

References | Related Articles | Metrics

A case of facial subcutaneous sporotrichsis caused by a multidrug-resistant Sporothrix schenckii strain was reported. A 61-year-old man had a history of facial plaques for 2 years. Whereas the patient had been treated with itraconazole, terbinafine and fluconazole successively for 16 months, the therapy was failed. According to mycological results of skin lesion, a diagnosis of sporotrichosis was made. However, the isolate of this case was not sensitive to itraconazole, terbinafine and fluconazole in both hyphae phase and yeast phase. The case had been cured by oral 10% potassium iodide for 3 months.

Advance in the study of Prototheca: from bench to bedside

KANG Yu-li, ZHANG Qiang-qiang

2012, (4):  242-246. 

Asbtract ( 2236 )   PDF (915KB) ( 1050 )  

References | Related Articles | Metrics

Prototheca is a unicellular organism with the cellular diameter about 3~30 μm.It exists in the nature and both in vitro and in vivo of the animal body, and it belongs to the opportunistic pathogenic fungus. The main methods to identify prototheca include direct microscopic examination, culture of the fungi, histopathology and molecular biology techniques. Prototheca includes 5 different species, and only the type 2 of Prototheca zopfii, Prototheca wickerhamii and Prototheca blaschkeae have pathogenicity to human. The pathogenic mechanism may be related to trauma and hypoimmunity in infected subjects. With the deepening research, more and more protothecosis were diagnosed. The therapy of protothecosis is different according to the species and their clinical manifestations. In order to increase the recognition of its pathogenicity, here we review briefly the advancement on the biology, identification, pathogenicity and clinical magnification of prototheca.

Pathogenic hydrolases of Candida albicans

MA Hu, CUI Fan, LIN Zhao-chun

2012, (4):  247-251. 

Asbtract ( 1605 )   PDF (849KB) ( 1536 )  

References | Related Articles | Metrics

Candida albicans is an important pathogenic fungus for human. Its pathogenicity is associated with various factors. Hydrolases belong to one of the most important virulence factors of C. albicans, which play a key role in fugal invasion. Pathogenic hydrolases of C. albicans comprise secreted aspartyl proteinases, phospholipases and lipases, which mediate phenotype conversion, adhesion to host tissue and intervention with host immune system.With these hydrolases,C. albicans is facilitated to invade host tissue and escaped from host anti-fungal immunity. Here we reviewed the updated studies in the biological and pathogenicity of C. albicans virulent hydrolases.