Fungal Interactions, Structures, and Their Ecological Roles
Fungal Mutualisms with Phototrophs
What is the Basis of Calling Lichens a Mutualism?
Fungi in lichens form a mutualistic relationship with a photosynthetic partner by creating a partnership that benefits both organisms. The fungus relies on the photobiont for organic nutrients produced through photosynthesis, such as glucose, which is essential for its survival in nutrient-poor environments. In return, the fungus provides a protective structure that shields the photobiont from environmental stresses
Read MoreUnderstanding Common Sexually Transmitted Infections and UTIs
Urinary Tract Infection (UTI) with Escherichia coli (E. coli)
E. coli is a common cause of UTI.
Risk Factors, Pathogenesis, and Clinical Manifestations
Risk Factors: Female gender, sexual activity, urinary stasis, catheter use, and diabetes.
Pathogenesis:
- Introduction of E. coli (usually from the gastrointestinal tract)
- Colonization of the urethra (via urethral opening)
- Adherence to uroepithelial cells (via fimbriae)
- Invasion of the bladder (Cystitis)
- Inflammation and immune response
- Symptoms of UTI (dysuria,
Sexually Transmitted Infections: Symptoms, Causes, and Treatment
Nongonococcal Urethritis (NGU)
Definition:
Nongonococcal urethritis (NGU) is an inflammation of the urethra caused by infections other than Neisseria gonorrhoeae. It is a common condition in sexually active individuals and a leading cause of urethritis.
Etiology:
The most common causes of NGU include:
- Chlamydia trachomatis – The primary causative agent.
- Mycoplasma genitalium – Often linked to recurrent or resistant cases.
- Ureaplasma urealyticum – Found in the urogenital tract.
- Herpes Simplex Virus
Bacterial and Viral Infections: Diagnosis and Treatment
Diphtheria: A Serious Bacterial Infection
Diphtheria is a serious bacterial infection of the throat.
Etiological Agents
The causative organism for diphtheria is Corynebacterium diphtheriae, a gram-positive, non-spore-forming, club-shaped bacterium.
Rarely, other Corynebacterium species (like Corynebacterium ulcerans and Corynebacterium pseudotuberculosis) may cause diphtheria-like symptoms, but C. diphtheriae is the primary cause.
Pathogenesis of Diphtheria
- Transmission: The bacteria are transmitted through
Respiratory Infections: Symptoms, Causes, and Treatment
BCG Vaccine
Full Form: Bacillus Calmette-Guérin vaccine.
Purpose: Prevents tuberculosis (TB), especially severe forms like miliary TB and tuberculous meningitis in children.
Type: Live attenuated vaccine derived from Mycobacterium bovis.
Administration:
- Route: Intradermal.
- Site: Deltoid region of the left arm.
- Age: At birth or within the first year.
Mechanism: Induces cellular immunity (T-cell response).
Adverse Effects: Local swelling, ulcer formation, regional lymphadenopathy, keloid scar.
Contraindications:
Read MorePertussis, Aspergillosis, Mucormycosis, and Other Infectious Diseases
Laboratory Diagnosis of Pertussis
Causative Agent: Bordetella pertussis, a gram-negative coccobacillus.
Pathogenesis
The bacteria attach to the ciliated epithelial cells of the respiratory tract using adhesins (filamentous hemagglutinin, fimbriae).
B. pertussis produces toxins:
- Pertussis toxin: Increases cAMP levels, leading to mucus production and tissue damage.
- Tracheal cytotoxin: Paralyzes and damages ciliated epithelial cells.
This causes characteristic cough and mucus accumulation.