In 1999 the name of the organism that causes a pneumonia in immunocompromised humans, commonly called pneumocystis pneumonia (PCP), was changed from Pneumocystis carinii to Pneumocystis jiroveci. (The causative organ ism for the rodent form of pneumocystis is still called P. carinii.) P. jiroveci is an opportunistic, atypical fungus that infects immunocompromised hosts and mostly manifests as PCP.

P. jiroveci originally was thought to be a trypanosome, but its precise taxonomic categorization remains challenging. Several factors supported the notion that P. jiroveci was a protozoan parasite: its morphology is similar to that of microbes and protozoa, and clinically it responds to antiprotozoal drugs but not to antifungal drugs in patients with pneumocystosis. Inability to maintain and propagate the organism in routine culture has further limited its characterization, although cultivation is possible under special conditions. P. jiroveci exists as three forms in its life cycle: trophozoite, precyst (sporocyte), and cyst (the latter is the diagnostic form).

Although P. jiroveci has been shown to be a fungus, it differs from other fungi in various aspects. Its cell mem brane contains cholesterol rather than ergosterol. The flexible-walled trophozoite is susceptible to osmotic disturbances. Also, P. jiroveci contains only one or two copies of the small ribosomal subunit gene, whereas most other fungi contain numerous copies of this gene. DNA sequence analysis of the small ribosomal subunit gene in P. jiroveci has disclosed a greater sequence homology with the fungi than with the protozoa. Two independent analyses that compared the DNA sequences of P. jiroveci with those of other fungi confirmed the placement of P. jiroveci in the fungal kingdom, somewhere between the ascomycetes and the basidiomycetes (the closest yeast is the fission yeast, Schizosaccharomyces pombe). DNA analysis also confirmed the difference between the rodent and human forms of pneumocystis.

اخر الاخبار

اخبار العتبة العباسية المقدسة

قسم التطوير يقيم دورة عن أخلاقيات المهنة للمنتسبين الجدد

تتضمن زيارة المراقد المقدسة في كربلاء.. معهد القرآن الكريم النسوي ينظم سفرة دينية لطالباته

المجمع العلمي يحتفي بذكرى ولادة الإمامين الباقر والهادي (عليهما السلام)

قسم الشؤون الفكرية يطلق فعاليات الأسبوع الثالث من برنامج البذرة الصالحة

المزيد

الآخبار الصحية

ثورة طبية.. الذكاء الاصطناعي يكشف سرطان الكلى في وقت قياسي

لتعزيز الطاقة والتغلب على التعب.. عليك بـ7 طرق بسيطة

لتحسين الهضم والتحكم في الشهية.. ما أفضل وقت لتناول التمر؟

خبراء يكشفون تأثير الاستحمام في الظلام على جودة النوم !

المزيد

الآخبار التكنلوجية

إزالة ثاني أكسيد الكربون من الغلاف الجوي.. ما دور المحيطات والبحار؟

نظائر الهيليوم مقياس لاكتشاف رواسب الذهب.. كيف ذلك؟

الصين تطلق أول ناقلة نفط خام ذكية في العالم تعمل بالميثانول

الزمن على المريخ أسرع من الأرض.. دراسة علمية تكشف الفوارق

المزيد

مواضيع ذات صلة

Conventional Yeast identification methods

Commercially available yeast identification systems

Approach to identification of the Yeasts

Specimen collection, transport, and processing of The Yeasts

Cryptococcus neoformans: pathogenesis and spectrum of disease

Candida albicans: pathogenesis and spectrum of disease

General characteristics of the Yeasts

Laboratory diagnosis of Pneumocystis jiroveci

Pathogenesis and spectrum of disease of Pneumocystis jiroveci

Approach to Identification of Systemic Mycoses

Pathogenesis and spectrum of disease of Systemic Mycoses

Epidemiology of Systemic Mycoses