Exam 4 New Material - 2 PDF

Airborne Bacterial Diseases Diphtheria → Corynebacterium diphtheriae (gram-positive bacteria) -​ Toxin-mediated → requires prophage -​ AB toxic mechanism → destroying cardiac, kidney and nervous tissues -​ Thick, gray pseudomembrane in pharynx -​ Inactivated toxoid vaccine Tuberculos...

Airborne Bacterial Diseases Diphtheria → Corynebacterium diphtheriae (gram-positive bacteria) -​ Toxin-mediated → requires prophage -​ AB toxic mechanism → destroying cardiac, kidney and nervous tissues -​ Thick, gray pseudomembrane in pharynx -​ Inactivated toxoid vaccine Tuberculosis → mycobacterium -​ Fever, fatigue, night sweats, weight loss and cough -​ 6-8 months of combination antimicrobial therapy Pertussis → gram-negative bordetella pertussis -​ Highly contagious -​ Fever, malaise, uncontrollable cough and cyanosis (skin discoloration) -​ whooping cough Arthropod-Borne Disease Lyme Disease -​ Tick borne → borrelia burgdorferi Three stages 1.​ Localizalized → ring shaped skin lesions + flu symptoms 2.​ Disseminated → neurological issues, heart inflammation and arthritis 3.​ Late stage → demyelination of neurons Diagnosis → serology testing or PCR Treatment → doxycycline Plague -​ Yersinia pestis (gram-negative) -​ Transmitted through fleas or direct contact with infected animals -​ Hemorrhages, fever, chills, enlarged lymph nodes -​ flea/rodent control -​ Vaccination for high-risk individuals Treatment → streptomycin Direct contact diseases Gas gangrene → clostridium perfringens -​ Infection of skeletal muscle by tissue damaging enzymes -​ Treatment → surgical removal of dead tissue + antimicrobial therapy -​ Amputation may be required STI -​ Chlamydia -​ Gonorrhea Tetanus → clostridium tetani -​ Tetanospasmin → spastic paralysis -​ Muscle cramping, lockjaw and facial spasms -​ Toxoid immunization Food and Waterborne Disease Botulism → clostridium botulinum toxin -​ Prevents acetylcholine release at motor neurons -​ Infant botulism → honey consumption -​ Respiratory failure and death Cholera → vibrio cholerae -​ Contaminated food and water -​ Dehydration and electrolyte imbalance -​ Treatment → dehydration and antibiotics Opportunistic Diseases Clostridium difficile -​ Hospital-acquired infection -​ Inflammation and diarrhea -​ Vancomycin or fecal transplant Dental and Periodontal disease -​ Bacterial plaque formation → tissue inflammation and bone deconstruction → tooth loss UTI -​ E. coli -​ More common in women due to shorter urethra -​ Can progress to kidney infection Emerging concerns Antibiotic concerns MRSA → B-lactam resistance Vancomycin → LAST resort Microbial Growth and Food Spoilage Intrinsic Factors (inherent part of food) -​ Carbohydrates → first spoiled by fungi (weaken fruit skin with enzymes) → allowing bacteria to colonize and produce hydrolytic enzymes -​ pH levels → low pH = yeast and mold (bread = sourdough) and high pH = bacteria -​ Dairy products → proteins and facts support bacterial growth -​ Putrefaction → anaerobic protein breakdown (sour smell) -​ Unpasteurized milk → acid production and growth of acid-tolerant organisms -​ Proteins and fat coagulate → milk turns clear -​ Grinding = increases surface area = microbe distribution -​ Natural antimicrobial substances → coumarins (fruits and vegetables), lysozyme in eggs, aldehydic and phenolic compounds in cinnamon, mustard and oregano Filtration → microorganisms removed from water, wine, beer, juices and other liquids Temperature control Low → slows down microbial growth -​ Listeria monocytogenes can still grow High -​ Appertization in canned food= high heat 25-100+ minutes -​ Kills spoilage microbes but not all microbes (+endospores) -​ Pasteurization → kills disease-causing microorganisms and reduces spoilage microbes Water control Dehydration + freeze drying → prevent microbial growth Other Preservation Methods Chemical → GRAS agents, organic acids, sulfite, ethylene oxide and sodium nitrate -​ Damage microbial plasma membrane and denature proteins Low pH → acetic and lactic acids inhibit microbial growth High Hydrostatic Pressure (packaged sealed and submerged under water)→ eukaryotic microbes -​ Gram positive less susceptible due to peptidoglycan layer (Radappertization) Radiation → X-ray beams, electron beams, gamma rays Modified atmosphere packaging (MAP) → vacuum technology, low CO2 concentration stops fungal growth, high oxygen = superoxide anion formation Categories Food-borne infections → growth after ingestion → tissue invasion and toxin release (listeria in deli meat and E.coli in salads) Food intoxication → toxin already present in food → S. aureus, clostridium botulinum, bacillus cereus Other toxins -​ Fungal → aflatoxins (grains and nuts) and fumonisins (corn) -​ Algal → fish and shellfish Fermented Foods Milk products → lactic acid bacteria → buttermilk, sourcream, yogurt and kefir Cheese → acidic fermentation, rennet addition → curd formation Alcoholic beverages -​ Wine (enology) → crushed grapes - must + sulfur dioxide to kill microbes → saccharomyces cerevisiae (yeast that breaks down carbs into alcohol) → fermentation -​ Beer → mashing, malting (starch → usable carbs) and hop (flavor) addition -​ Heating = inactivates hydrolytic enzymes -​ Distilled spirits → sour mash → extended beer production with higher alcohol content -​ Homolactic bacteria → lowers pH Bread → saccharomyces cerevisiae → CO2 = rising -​ Can be spoiled by bacillus species Microbial Products and Applications Industrial products → ethanol, acetone and butanol Medical → antibiotic, insulin, growth hormones Food additives → amino acids, organic acids and vitamins Polysaccharides Antibiotics → mostly produced by streptomyces -​ Precise nutrient controls -​ Penicillin can be modified → semi synthetic versions Amino Acids and Organic Acids -​ Nutritional supplements and flavor enhancers -​ Glutamate → mutant microbe lacking convert alpha-ketoglutarate to succinyl-CoA → glutamate released to medium -​ Organic acid - preservatives (Citric acid) → high sugar stress stops Aspergillus niger growth → citric acid accumulation and release Enzymes -​ Bacterial and fungal hydrolysis → natural polymers (starches and proteins) -​ Food processing -​ Laundry and detergents for stain removal Vaccines and Immunology -​ Genomic and molecular approaches -​ Reverse vaccinology → identifies potential antigens from pathogens -​ Monoclonal antibodies → design peptide that mimics immunogenic pathogen → vaccine Antigen requirements: -​ Expression during infection -​ Surface location -​ Present across all strains -​ Immune stimulation -​ Essential for pathogen survival Biofuel Production Ethanol (corn by amylase) → gasoline additive -​ From plant starch using enzymatic degradation Challenges -​ Water absorption -​ Lower energy content -​ Transportation limitations  -​ Food price impacts → more plants = more fertilizer = more cost and contamination -​ Use crop residues instead Hydrogen → highest energy content -​ Cannot mix with gasoline -​ Anaerobically -​ Oxygenic photosynthetic microbes → H2 at night -​ hydrogenase inhibition (self-limiting feedback loop) Industrial Microbial Growth -​ Mass culture -​ Maintenance of microenvironment -​ Continuous feed systems → prevent waste accumulation Metabolite production -​ Primary → exponential growth (amino acids, nucleotides and enzymes) -​ Secondary → nutrient limitation or stress (antibiotics) Agricultural Biotechnology -​ Genetic engineering → DNA transfer to plant chromosomes -​ Applications to bioinsecticides and biopesticides -​ Bacillus thuringiensis → insecticidal proteins -​ Protoxin is proteolyzed → active toxin → channel through midgut → cell lyses Emerging Technologies -​ Diatoms → photosynthesis protist - cut wax coating on insects -​ Biosensors → riboswitches + GFP → monitor fluoride levels in water -​ Heme → repressor/inducer model system (biosensor lights up in presence of blood) -​ Association of inducer + heme when bound to operator/promoter → protein light transcribed