Äîêóìåíò âçÿò èç êýøà ïîèñêîâîé ìàøèíû. Àäðåñ îðèãèíàëüíîãî äîêóìåíòà : http://www.cosmos.ru/conf/2009elw/presentations/presentations_pdf/session7/digel_ELW.pdf Äàòà èçìåíåíèÿ: Mon Mar 2 19:59:33 2009 Äàòà èíäåêñèðîâàíèÿ: Mon Apr 6 23:50:56 2009 Êîäèðîâêà:

I. Digel1, B. Dachwald2 G.M. Artmann1, P. Linder1, O. Funke3

I. Digel B. Dachwald G.M. Artmann P. Linder O. Funke

A Concept Of A Probe For Particle Analysis And Life Detection In Icy Environments


Amateur´s Opinion
Points of Interest: · Ice Penetration · In-situ Decontamination · In-situ Detection of Bacteria


Ice Penetration

· · · ·

Conventional Drilling Autonomous Drilling A Melting Probe A Melting/Drillig Probe


In-situ Decontamination:
· · · · Guideline: Planetary Protection Criteria Consequent Selection Results


Our criteria for a proper in-situ decontamination method:
· High killing rate and activity against broad range of microorganisms, spores, fungi, viruses, small insects and worms (sic!) · Fast decomposing and environmental ,,friendly" end products · Good solubility in water · Good penetration ability · Activity in relatively cold environments · Easy storage, handling and application · Cost · Better: a subsequent application of 2-3 compounds (!)


Antiseptics and disinfectants
· · · · · · · · · · · Acridine derivatives Ethacridine lactate · Aminoacridine · Euflavine Biguanides and amidines Dibrompropamidine · Chlorhexidine · Propamidine · Hexamidine · Polihexanide Phenol and derivatives Hexachlorophene · Policresulen · Phenol · Triclosan · Chloroxylenol · Biphenylol Nitrofuran derivatives Nitrofurazone Iodine products Iodine/octylphenoxypolyglycolether · Povidone-iodine · Diiodohydroxypropane Quinoline derivatives Dequalinium · Chlorquinaldol · Oxyquinoline · Clioquinol Quaternary ammonium compounds Benzalkonium · Cetrimonium · Cetylpyridinium · Cetrimide · Benzoxonium chloride · Didecyldimethylammonium chloride Mercurial products Mercuric amidochloride · Phenylmercuric borate · Mercuric chloride · Mercurochrome · Thiomersal · Mercuric iodide Silver compounds Silver nitrate Alcohols Propanol (Propyl Alcohol · Isopropanol (Isopropyl Alcohol) · Ethanol (Ethyl Alcohol) · Other Potassium permanganate · Sodium hypochlorite · Hydrogen peroxide · Eosin · Tosylchloramide sodium .....


Common pesticides with established efficacy (EPA standards) · Bleach (sodium hypochlorite)/chlorine dioxide · Ethylene oxide, · Hydrogen peroxide · Peroxyacetic acid, · Methyl bromide, · Formaldehyde/paraformaldehyde contamination Boron · Perborate ("persil") · Percarbonate/pseudopercarbonate


Bleach (sodium hypochlorite)
· Chlorination of water (swimming pool) · + Is allowed for food processing equipment: A weak solution of 1% household bleach in warm water is used to sanitize smooth surfaces prior to brewing of beer or wine · - corrosive


Methyl bromide
· + Safe and efficient soil sterilant · + occurs naturally in the ocean, where it is found in some species of algae · - its use is curtailed by the Montreal Protocol (the list of banned ozone-depleting substances)


Peroxyacetic acid
· + very efficient and fast antimicrobial agent (OH.) · + no resistant microorganisms exist · + can damage virtually all types of macromolecules associated with a microorganism: carbohydrates, nucleic acids, lipids and amino acids = no organic contamination · + end products: acetic acid (!) and hydrogen peroxide (!) · very effective at low temperatures · - highly corrosive · - being pure can explode at elevated temperatures


Formaldehyde/paraformaldehyde
· Saturated water soution = formaline H2C(OH)2 · +/- Environmental concerns · - Toxic, allergic, carcinogenic · - Variety of chemical reactions · Kills most bacteria, fungi (including their spores), and parasites. Also used in vaccines · +/- Preserves/inactivates organic molecules by cross-linking


Ethylene oxide
· + well-studied bactericidal effects, ,,standard" · - end product in reaction with water is ethyleneglycol and ist derivatives · - gaseous · - potentially carcinogenic


Percarbonate/pseudopercarbonat e
· True percarbonates MeO-CO-O-OH are highly unstable · "Sodium percarbonate" is in reality a mixture 2 Na2CO3 · 3 H2O2 · +/- solid · - unstable at 60°C · - creates very alkaline pH


Hydrogen Peroxide H2O

2

· + Can operate at low temperatures · + Humidity level is not as critical as with formaldehyde · + Is residue free · + Has fast "kill" times · + Is a fully validated technology · - microorganisms having catalase or peroxidase have a chance to survive · -?


In situ Decontamination: a Car Wash Approach


Suggestion:
Two-step in-situ decontamination process is suggested, consisting of a consequent application of two of the following compounds: 1. 2. 3. 4. Sodium hypochlorite Peroxyacetic acid/Hydrogen peroxide Methyl bormide Sodium percarbonate


Life Detection:
Challenge: · rapid · in-situ · non-invasive method for detection, quantification and identification of microscopic organisms in water and glacial environments


Approaches Evaluated:
· Autofluorescence · Light Scattering · Flow Cytometry


Autofluorescence:
·+
Non-invasive Easy to apply

·Low specificity Weak signal


Autofluorescence may carry useful biological information as well:
· NADH can be used to monitor metabolic state of living tissues and for redox fluorometry, redox NAD(P)H imaging flavoprotein may be used for imaging and redox state detection of intracellular flavins using flow cytometry or fluorescence microscopy FAD fluorescence has been used for identification and cell sorting of eosinophils and neutrophils.

·

·


Fluorescent molecules naturally present in animal tissues
Fluorescent compound Aromatic amino acid residues: Tryptophan Tyrosine Phenylalanine Pyridine nucleotides (reduced) NADH NADPH Flavins and flavin nucleotides (oxidized) riboflavin, FMN and FAD, mostly bound to enzymes as coenzymes of flavoproteins, concentrated to mitochondria, also present in cytoplasm and outer membrane connective tissue Localization cofactors in metabolism, concentrated to mitochondria, also present in cytoplasm 280 274 257 cofactors in metabolism, concentrated to mitochondria, also present in cytoplasm 290 351 336 22 26 37 44 0 5 0 0 0 0 0 0 0 3 8 4 9 440 460 464 broad maximum around 530 31 38 39 53 34 40 42 50 52 0 5 0 0 0 5 0 0 0 348 303 282 Excitation maxima [nm] Emission maxima [nm]

Collagen

28 26 33 45 29 32 35 41 45

Elastin

connective tissue

Endogenous porphyrins Lipofuscin

In erythroid cells Pigment granules accumulated with age in various cells

400-500 360

630 690 450


Light Scattering:
·+
Non-invasive Very sensitive

·Noise Difficult to interpret


Flow Cytometry
In 1947 Gucker and colleagues: "The principle (of flow cytometry) should have wide application in (. . .) bacteriology."

·+

Non-invasive Very sensitive (single cell counting)

·Noise Difficult to interpret


Thank you