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Kam jābūt uz Padlet sienas un kas būs ar to jādara?
(1) 5 minūšu prezentācija par grupai iedalīto dzīvo organismu valsts šūnas analīzi (iekļauti piemēri un papildus informācija).
(2) Pēc prezentācijas vai tās laikā katrai grupai jāuzdod 3 jautājumi klasesbiedriem.

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Sēnēm ir eikariotu šūnas.
Sēnes sastāv no mikroskopiskiem pavedieniem - hifām.

Hifas savijoties veido micēliju, kas atrodas jebkādā substrātā, no kura var uzņemt organiskās vielas. (Micēliji ir sēņu saknes)

Sēņu šūnapvalks satur hitīnu. Sēņu šūnās nav plastīdu.

Sēņu šūnapvalks stingri nenorobežo šūnu no šūnas, tāpēc sēņu citoplazma var pārvietoties no vienas šūnas uz otru.

Labos apstākļos micēlijs veido augļķermeņus, uz kuriem attīstās sporas.
Sporas nokļūstot uz pareiza substāta, dīgst.
Ar pietiekamu mitruma un siltuma daudzumu, no sporām veidojas misēlijs.

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INFORMĀCIJU UN TĀS NOZĪMĪGUMU IZVĒLATIES PAŠI (iesaku padomāt par uzbūvi, daudzveidību, kādu piemēru, kā atšķirt no citām šūnām u.tmldz.)

(1) Iekļaut šūnas bioloģisko zīmējumu (shematiski), kā arī atrast mikroskopa attēlu (norādīt palielinājumu, mikroskopa veidu).
(2) Atrast kādu interesantu faktu (balstīt zinātniskajā pētījumā/rakstā).
(3) BŪS JĀVEIDO ŠŪNAS MODELIS (no otrreizēji izmantojamiem materiāliem).

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• plazmatiskā membrāna - nodrošina šūnas suverenitāti, norobežo šūnu no ārvides
• šūnapvalks -  apņem, balsta un aizsargā šūnu
• DNS -  glabā ģenētisko informāciju
• vica -  nodrošina baktēriju pārvietošanos
• fimbrija - piestiprināšanās organoīds
• citoplazma - aizņem šūnas telpu

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Vieņšūņi jeb protozoji ir polifilētiska eikariotisku vienšūnas organismu grupa ar heterotrofu barošanās veidu.

Tos atklāja 1675. gadā pirmā mikroskopa izgudrotājs holandietis Antonijs van Lēvenhuks.

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1. Arheji ir vienšūnu prokarioti, kas molekulārā līmenī būtiski atšķiras gan no baktērijām, gan no eikariotiem.

2. Arheju šūnu vidējais diametrs ir ap 1 μm un garums vidēji 5 μm.

3. Šūnu forma ir visdažādākā. Sastopamas ir sfēriskas, iegarenas, spirāliskas, trīsstūra un taisnstūra formas.

4. Daudziem arhejiem ir viciņas, kuru sastāvā, atšķirībā no baktērijām, ietilpst vairāku veidu flagellīni.

5. Arheji nespēj sintezēt sarežģītus hidrolītiskus fermentus, tāpēc tie lielākoties spēj pārstrādāt tikai vienkāršākās organiskās vielas.

6. Arheji ir plaši izplatīti apkārtējā vidē, tostarp aizņemot nišas, kas nav pieejamas citām dzīvības formām. Dažas arhejas dzīvo vides apstākļos, kas tiek uzskatīti par pārāk ekstrēmiem, lai visa zināmā dzīvība varētu izdzīvot dodod viņiem nosaukumu - ekstremofili .

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• Baktērijas sastāda lielāko daļu no prokariotu šūnu grupas.
• Prokariotu šūnas ir visvienkāršākās un senākās šūnas.
• Baktēriju tipu iedalījums pēc formas:
1. Lodveida baktērijas
2. Nūjiņveida baktērijas
3. Spirālveida baktērijas

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Sēņu šūnām ir raksturīgs šūnapvalks.
Tās veido smalkus šūnu pavedienus - hifas.

Organoīdi:

- Kodols (Satur iedzimtības informāciju
- Mitohondrijs (Šūnas spēkstacija)
- Šūnapvalks (Mehāniski balsta un aizsargā šūnu)
- Plazmatiskā membrāna (Nodrošina vielu apmaiņu starp citoplazmu un vidi)
- Goldži pūslīts (Izdala vielas ārpus šūnas un veido lizosomas)
- Goldži komplekss (Uzkrāj ET sintezētās vielas un transportē tās pūslīšu sastāvā)
- Ribosoma (Sintezē olbaltumvielas)
- Endoplazmatiskais tīkls (Veic olbaltumvielu sintēzi, pārveidošanu un transportu)

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•Auga šūna ir eikariotiska šūna.

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Vienšūņi dzīvo visās ūdenstilpēs (no peļķes līdz okeānam), mitrā augsnē, augos, dzīvniekos un cilvēkā.

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• Baktēriju šūnu īpašības, kas tās atšķir no citām šūnām:
1. Nav kodola, bet ir kodolviela (nukleoīds), jo ģenētiskais materiāls no citoplazmas nav norobežots ar kodolapvalku.

2. Atsevišķām baktērijām ir fimbrija jeb pili (piestiprināšanās organoīdi). Tās atšķirās gan pēc veida, gan uzbūves, tāpēc arī to funkcijas ir dažādas.

3. Ir kapsula, kas apņem šūnapvalku un nodrošina šūnai papildus aizsardzību no ārējās vides, piemēram, no mehāniskiem bojājumiem, izžūšanas un inficēšanās ar toksiskām vielām.
4. Lielākajai daļai baktēriju ir vica/vicas, kas nodrošina baktēriju pārvietošanos.

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Zināmas aptuveni 50000 sugas.

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Kustīga, vīrišķā dzimumšūna.
Gandrīz visu galviņu aizņem kodols, tas satur tēva ģenētisko informāciju, kas apaugļošanas laikā tiek nodota pēctecim. Pa visu astīti stiepjas astītes pavediens, ap kuru kakliņam tuvākajā daļā spirālveidā novietoti mitohondriji, kas dod enerģiju spermatozoīda kustībām.

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• Mainīgā amēba, zaļā eiglēna un lamblijas pieder pie sarkodīnvicaiņu tipa
• Tupelīte un bursārija ietilpst skropstaiņu jeb infuzoriju tipā (To pazīme ir daudzas skropstiņas uz ķermeņa virsmas)
• Eiglēna, zaļā eiglēna ir mikroskopisks vienšūnas organisms, kas barojas miksotrofi.
• Sarkodīnas un vicaiņi, kā arī skropstaiņi dzīvo galvenokārt saldūdeņos un jūrās. Pārējie vienšūņi ir parazīti.

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Spirostrombidium sp, optiskais mikroskops.

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Strombidium sp, optiskais mikroskops.

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Puse no mikrobu šūnām Zemes okeānos atrodas nogulumos. Daudzas no šīm šūnām ir arhejas un vienšūnu prokarioti, kas ir atdalīti no baktērijām un eikariotiem.
Visas četras no pētītajām šūnām kodēja proteīnus noārdošos enzīmus. Turklāt mēs atklājām, ka šie divi peptidāzes veidi ir bagātīgi un aktīvi jūras nogulumos, norādot, ka nekultivētām arhejām var būt iepriekš neatklāta loma proteīnu remineralizācijā bezoksiskajos jūras nogulumos.

https://www.nature.com/articles/nature12033

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Abstract

Half of the microbial cells in the Earth's oceans are found in sediments. Many of these cells are members of the Archaea, single-celled prokaryotes in a domain of life separate from Bacteria and Eukaryota. However, most of these archaea lack cultured representatives, leaving their physiologies and placement on the tree of life uncertain. Here we show that the uncultured miscellaneous crenarchaeotal group (MCG) and marine benthic group-D (MBG-D) are among the most numerous archaea in the marine sub-sea floor. Single-cell genomic sequencing of one cell of MCG and three cells of MBG-D indicated that they form new branches basal to the archaeal phyla Thaumarchaeota and Aigarchaeota, for MCG, and the order Thermoplasmatales, for MBG-D. All four cells encoded extracellular protein-degrading enzymes such as gingipain and clostripain that are known to be effective in environments chemically similar to marine sediments. Furthermore, we found these two types of peptidase to be abundant and active in marine sediments, indicating that uncultured archaea may have a previously undiscovered role in protein remineralization in anoxic marine sediments.

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Accession codes

Primary accessions

GenBank/EMBL/DDBJ

Data deposits

This whole-genome shotgun project has been deposited at DDBJ/EMBL/GenBank as Thaumarchaeota archaeon SCGC AB-539-E09 (accession number ALXK00000000), Thermoplasmatales archaeon SCGC AB-539-C06 ( AOSH00000000), Thermoplasmatales archaeon SCGC AB-539-N05 ( ALXL00000000) and Thermoplasmatales archaeon SCGC AB-540-F20 ( AOSI00000000).

References

1. Schut, G. J., Menon, A. L. & Adams, M. W. W. 2-keto acid oxidoreductases from Pyrococcus furiosus and Thermococcus litoralis. Methods Enzymol. 331, 144-158 (2001)

2. Miller, M. A., Pfeiffer, W. & Schwartz, T. Creating the CIPRES Science Gateway for inference of large phylogenetic trees. Gateway Computing Environments Workshop. 1-8 (2010)

3. Jørgensen, B. B. Case study-Århus Bay. Eutrophication in Coastal Marine Systems 137-154 (American Geophysical Union, 1996)

4. Stahl, D. A. & Amann, R. Development and Application of Nucleic Acid Probes (Wiley, 1991)

Google Scholar

5. Nakayama, K., Kadowaki, T., Okamoto, K. & Yamamoto, K. Construction and characterization of arginine-specific cysteine proteinase (Arg-gingipain)-deficient mutants of Porphyromonas gingivalis: Evidence for significant contribution of Arg-gingipain to virulence. J. Biol. Chem. 270, 23619-23626 (1995)

6. R Core Team. R: A language and environment for statistical computing. R Foundation for Statistical Computing http://www.rproject.org (2012)

Download references

Acknowledgements

The authors thank the captain and crew of the R/V Tyra for sampling; T. B. Søgaard, A. Stentebjerg and B. Poulsen for technical work; F. Löffler for laboratory space; and D. Kirchman and S. Hallam for sharing their unpublished metagenomic data sets. This work was funded by the Danish National Research Foundation, the German Max Planck Society, NSF Center for Dark Energy Biosphere Investigations NSF-157595 (K.G.L.), The Danish Council for Independent Research-Natural Sciences (D.G.P.), the Villum Kann Rasmussen Foundation, an EU Marie Curie fellowship (M.A.L.), the German Research Foundation (S.L.) and the USA National Science Foundation awards EF-826924, OCE-821374 and OCE-1019242 (R.S.).

Author information

Author notes

Karen G. Lloyd and Lars Schreiber: These authors contributed equally to this work.

Authors and Affiliations

1. Department of Bioscience, Center for Geomicrobiology, Aarhus University, Aarhus 8000, Denmark,

Karen G. Lloyd, Lars Schreiber, Dorthe G. Petersen, Kasper U. Kjeldsen, Mark A. Lever, Andreas Schramm & Bo Barker Jørgensen

2. University of Tennessee, Knoxville, 37996, Tennessee, USA

Karen G. Lloyd & Andrew D. Steen

3. Bigelow Laboratory for Ocean Sciences, East Boothbay, 04544, Maine, USA

Ramunas Stepanauskas

4. Ribocon GmbH, Bremen 28359, Germany,

Michael Richter

5. Max Planck Institute for Marine Microbiology, Bremen 28359, Germany,

Sara Kleindienst & Sabine Lenk

Contributions

K.G.L., L.S., D.G.P., K.U.K., R.S., A.S. and B.B.J. worked together to design experiment and develop the method for single cell sorting from sediments. K.G.L. wrote the main paper and developed the protein degradation hypothesis. L.S. wrote the Supplementary Information, designed and performed bioinformatic analyses. K.G.L. and L.S. performed phylogenetic tests. K.G.L. and D.G.P. reconstructed metabolic pathways with SAG genes. R.S. performed cell sorting and amplification. S.K., S.L., D.G.P. and L.S. developed protocols for cell separation from sediments. K.U.K. performed and analysed 16S rRNA gene amplicon sequencing; M.A.L., L.S. and K.G.L. performed quantitative PCR; A.D.S. performed enzyme activity measurements; and M.R. gave bioinformatic support and added quality control tests. A.S. and B.B.J. obtained the major funding for this work. All co-authors commented on and provided substantial edits to the manuscript.

Corresponding author

Correspondence to Karen G. Lloyd.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

This file contains Supplementary Materials and Methods, Supplementary Tables 1-7 and 9-12 (see separate file for Supplementary Table 8), Supplementary Figures 1-10 and additional references. (PDF 1842 kb)

This file contains Supplementary Table 8. (XLSX 44 kb)

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Predominant archaea in marine sediments degrade detrital proteins - Nature

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Miscellaneous crenarchaeotal group (MCG) and marine benthic group-D (MBG-D) are among the most numerous archaea in sea-floor sediments; single-cell genomics reveals that these archaea belong to new branches of the archaeal tree and probably have a role in protein remineralization in anoxic marine sediments.

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• Vienšūņi elpo. Skābeklis nonāk to citoplazmā caur visu ķermeņa virsmu. Apgādā ar skābekli organiskās vielas, līdz tās pārvēršas par ūdeni, oglekļa dioksīdu un citiem savienojumiem.
• Oglekļa dioksīds elpošanas procesā, izdalās pār visu ķermeņa virsmu.

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Vienšūņiem ir liela nozīme dabā un cilvēka dzīvē, piemēram, tupelītes attīra ūdeni un aprij daudz baktērijas.

Vienšūņi noder par barību zivju mazuļiem, vēžiem un odu kāpuriem.

Čaulainie sarkodīni, kad nogrimst okeāna vai jūras dibenā un aiziet bojā, tās veido kaļķa nogulas. No tā var izgatavot krītus, ar kaļķa noguļām var balināt ēku sienas un griestus, kā arī kaļķakmens, no kura ceļ namus, sastāv galvenokārt no dzīvnieciņu čaulām.

Daudzu sugu vienšūņi parazitē dzīvniekos un cilvēkos. Var rasties zarnu slimības, iekaisumi žultspūslī, rada brūces resnajā zarnā. Malāriju, bīstamu slimību, izraisīja sporaiņu tipam piederošais malārijas plazmodijs.

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• Amēbas ir mikroskopisku vienšūnas organismu ģints.

• Nepastāvīga ķermeņa forma, jo nepārtraukti veidojas māņkājiņas jeb pseidopodijas.

•Tās vairojas mitozes procesā, bezdzimumiski.

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*Eikariotru šūna

*Dzīvnieku šūna, enerģijas ieguvei oksidē cukurus, lai radītu jaunas šūnas, dalās.
*Tās pamatfunkcija ir uztvert barības vielas, kuras dzīvnieks iegūst no ārpuses, pārveidot tās par vielām, kuras vēlāk izmantos enerģijas ražošanai un likvidēt tā radītos atkritumus.

Tā sastāv no :

1. Kodoliņa - tas atrodas iekš kodola, ražo ribosomas.

2. Kodola - organoīds kurš satur iedzimtības informāciju, regulē šūnas darbību.

3. Ribosomas - sintizē olbaltumvielas.

4. Graudainā un gludā endoplazmatiskā tīklā- vislielākie organoīdi, plakanu membrānu un kanāliņu sistēma, kas caur auž citoplazmu.
Uz graudainā endoplazmatiskā tīkla membrānā citoplazmas pusē ir ribosoma, bet uz gludā - ribosomu nav.

5. Goldži kompleksa - uzkrāj ET sintizētās vielas un transportē tās pūslīšu sastāvā. Pūslīši insala vielas ārpus šūnas vai vendo lizosomas.

6. Citoskeleta - blīvs pavedienu tīkls citoplazmā, kas piešķir šūnai formu un nodrošina iekššūnu transportu, vido šūnas basta sistēmu.

7.  Mitohondrijiem - mitohondriji šūnu apgādā ar enerģiju. Jauni mitohondriji veidojas no vecajiem

8. Vakuolas - uzkrāj rezerves vielas, regulē šūnu spiedienu. Galvenā nozīme ūdens uzsūkšanā šūnā.

9. Citoplazmas - aizņem šūnas telpu starp

plazmatisko mebrānu un kodolu. Tā sastāv no hialoplaas, organoīdiem, citoskeleta un ieslēgumiem.

10. Lizosomas - šūnas gremošanas organoīdi. Tie ir ar membrānu apņemti pūslīši, kas satur dažādus hidrolītiskos (gremošanas) fermentus.

11. Centriolas - tās funkcija ir ražot un sakārtot pavedienus, kas būs nepieciešami šūnu dalīšanās laikā.
12. Plazmatiskā mebrāna - nodrošina šūnas suvernitāti un komunikāciju. Tā no ārpuses apņem dzīvnieku šūnu.
13.  Centrosomas - tā sastāv no divām centriolām. Atrodas netālu no kodola un tai ir svarīga loma šūnas dalīšanās laikā.

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• Tupelītes ķermenim ir kurpes zoles forma.

•Pārvietošanos nodrošina daudzās skropstiņas

•Tupelītei, atšķirībā no amēbām, ir šūnas mute un rīkle. Barību ievada mutē, vēzējot ap muti esošās skropstiņas.

•Tupelītes vairojas daloties. Laiku pa laikam tupelītēm notiek dzimumprocess - divas tupelītes satuvinās un apmainās ar mazo kodolu daļām. Tā notiek iedzimtības informācijas apmaiņa starp diviem īpatņiem.

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• Piesārņotos ūdeņos bieži ir sastopama zaļā eiglēna.

•Tā izskatās zaļa, jo ķermenī ir daudz ovālu graudiņu, kas satur hlorofilu.

•Tās vairojas, daloties uz pusēm.

•Eiglēnas ir iespējams izmantot kosmētikā, izejvielu biomateriāliem, pārtiku dažādiem mājlopiem un ūdensdzīvniekiem. Tās izmanto arī netīru un piesārņotu ūdenstilpju attīrīšanai. Japānā tās arī izmanto uzturā. Euglena Company Tokijā kultivē šo mikroorganismu tādos daudzumos, ka to var komerciāli izmantot. Notiek arī izpēte, vai no eiglēnas var ražot biodegvielu

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Bildē ir izteikti redzemi hloroplasti(zaļā krāsā), šūnapvalks(satur šūnu no ārpuses), citoplazma (aizņem šūnas telpu starp kodolu un menbrānu), kodols( glabā dns)

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Augu vīruss:
•Vīrusi nesastāv no šūnapvalka, bet gan no olbaltumvielu apvalka.
•Lai vīrusi spētu funkcionēt un, tiem nepieciešams atrasties dzīvā organismā.
•Vīrusi ir šūnu parazīti – vīruss izmanto auga resursus, lai izdzīvotu, nedodot nekādu labumu.
•Par cik vīrusi uzturās auga sulā, tie pārvietojas, pārnesājot to, piemēram, ar dārza šķērēm.

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•  Zinātnieki ir atraduši iespēju kā mikroskopā izpētīt vissīkākās šūnas struktūras. Šajā pētijumā ar ļoti specifiskiem aparātiem (krioelektronmikroskopijas un caurstarojošās elektronmikroskopijas )palīdzību izdevās noskaidrot šūnas vissmazākās daļiņas izmērus un ārējo uzbūvi.
• Pētijuma mērķis ir iemācīt cilvēcei eksistējošajos, dabā sastopamajos baktēriju mikronodalījumos nomainīt tajos esošos enzīmus pret citiem, farmācijā vai biotehnoloģijā svarīgiem, tad šiem mikronodalījumiem būtu plašs pielietojums.

https://www.lu.lv/par-mums/lu-mediji/zinas/zina/t/57335/

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Folia Microbiol (Praha). 2011; 56(5): 469-475.

Abstract

Simple and effective protocols of cell wall disruption were elaborated for tested fungal strains: Penicillium citrinum, Aspergillus fumigatus, Rhodotorula gracilis. Several techniques of cell wall disintegration were studied, including ultrasound disintegration, homogenization in bead mill, application of chemicals of various types, and osmotic shock. The release of proteins from fungal cells and the activity of a cytosolic enzyme, glucose-6-phosphate dehydrogenase, in the crude extracts were assayed to determine and compare the efficacy of each method. The presented studies allowed adjusting the particular method to a particular strain. The mechanical methods of disintegration appeared to be the most effective for the disintegration of yeast, R. gracilis, and filamentous fungi, A. fumigatus and P. citrinum. Ultrasonication and bead milling led to obtaining fungal cell-free extracts containing high concentrations of soluble proteins and active glucose-6-phosphate dehydrogenase systems.

The microbial world offers a variety of products important and useful for human life, including chemical intermediates, antibiotics, enzymes, and therapeutic agents. Some of them are produced by microbes and are excreted into the cultivation medium and easily isolated. In contradiction, isolation and canvassing of intracellular products often require complicated sequences of operations. This task usually starts from a cell disruption process. Disintegration of cells precedes the fractionating and purification of constituent of the cell structures and influences the quality of the final product (Savov et al. 2001). Various cell disruption methods have been developed to establish an efficient, low-cost, and effective release of intracellular products (Middelberg 1995; Geciova et al. 2002; Ho et al. 2008). The application of certain disintegration techniques depends on such cell properties as physical strength of the cell wall and intracellular location of the desired product (Sauer et al. 1989; Kuboi et al. 1995). Complete destruction of the microbial cell in a nonspecific manner is usually achieved by ultrasound disruption of the cell (Borthwick et al. 2005; Gogate and Kabadi 2009). This process can proceed via complete breakage of the individual cells, releasing all intracellular enzymes, or it can be shear-driven, where only the cell wall breaks and as a result only the enzyme present in the cell wall or periplasm will be released (Balasundaram and Pandit 2001). The mechanism of cell disruption is associated with the cavitation phenomena, shear stress developed by viscous dissipative eddies arising from shock waves produced by imploding cavitation bubbles (Middelberg 1995; Harrison 1991; Garcia 1993). Another mechanical method to damage microbial cell walls of different structures is bead milling, applied successfully in both laboratory and industrial scales (Doucha and Livansky 2008). Compounds are released from cells due to the action of circulating beads dispersed in the fluid (Middelberg 1995; Doucha and Livansky 2008; Heim et al. 2007). A bead mill can be operated either in batch (Ricci-Silva et al. 2000) or in a continuous recycling mode (Ho et al. 2008). For a large-scale disintegration of the biological material, the mechanical method (the high-pressure homogenizer) is usually used. High-pressure cell opening is achieved by passing them through an adjustable, restricted orifice discharge valve (Engler 1985; Hetherington et al. 1971; Keshavarz-Moore et al. 1990; Kelly and Muske 2004). Non-mechanical processes have also been designed as alternatives to mechanical techniques, but the process-scale application is a crucial limitation in this case (Yasotha et al. 2006; Joubert and Fleurence 2008; Denis et al. 2009). The advantages of the application of enzymes are gentle process conditions and their specificity (Middelberg 1995; Kitamura 1982; Taskova et al. 2006; Ablain et al. 2009). Unfortunately, enzymatic digestion of the cell wall may be too expensive when it is used in a large scale. Permeabilization or lysis of cells can be performed also by chemical treatment. Antibiotics, chelating agents, detergents, and solvents are capable of disintegrating the cells (Dean and Ward 1992; Al-Samarrai and Schmidt 2000; Corrado and Rodrigues 2004; Leuko et al. 2008; Doolan and Wilkinson 2009). These procedures rely on the selective interaction of the chosen chemicals with components of the membrane and allow proteins to seep through the cell wall. There are at least two physical procedures-osmotic shock and thermolysis-also used for cell disintegration (Chen et al. 2004; Tkac et al. 2004; Ren et al. 2007a, b). The application of two or more procedures combined with the cells wall disruption is also reported (Anand et al. 2007; Lim et al. 2008; Chaves-Lopez et al. 2009; Shynkaryk et al. 2009).

Most of the published articles were focused on the disruption of Escherichia coli (Gram-negative bacteria), Bacillus subtilis (spore-forming Gram-positive bacteria), or yeast ( Saccharomyces cerevisiae or Candida utilis; Ho et al. 2008; Ren et al. 2007a; Anand et al. 2007; Lim et al. 2008; Chaves-Lopez et al. 2009; Shynkaryk et al. 2009; Fonesca and Cabral 2002; Agrawal and Pandit 2003). Literature data devoted to other microorganisms, especially fungi, are relatively scarce (Taubert et al. 2000), meaning that they are still a not fully explored source of intracellular compounds of possible industrial applications. Therefore, this report focuses on the rationally planned studies performed in order to elaborate effective disruption methods (both mechanical and non-mechanical) using Rhodotorula gracilis, Aspergillus fumigatus, and Penicillium citrinum as model objects.

Materials and methods

Chemicals

All chemicals were purchased from commercial suppliers: Difco, POCh, Sigma-Aldrich.

Fungal strains

R. gracilis ( Rhodosporidium toruloides) DSM 4444, was from DSMZ, Germany. A. fumigatus was a kind gift from the University of Pavia, Italy. P. citrinum was a kind gift from the University of Opole, Poland.

Cultivation media

A. fumigatus and P. citrinum were cultivated on a potato dextrose broth (Difco). R. gracilis was cultivated on a malt extract peptone broth (Difco). Microbial cultivation media were prepared according to the instructions of the suppliers and autoclaved.

Cultivation methods

Fungi were cultivated in 250-mL flasks containing 50 mL of the corresponding medium until the mid-log phase (25°C, 150 rpm, RT). After 5 days for yeast and 3 days for fungi, biomass was separated by centrifugation (10 min, 4,000 rpm, 4°C). The biomass was pooled and washed twice with buffer (Tris 5 mmol/L, pH 7.5).

Disintegration procedure

Samples of washed biomass (6.5 g) were suspended in 15 mL of cold buffer (Tris 50 mmol/L, pH 7.5) and disintegrated according to the procedures described below. The efficiency of cell disruptions was monitored by measuring two parameters: concentration of the soluble proteins in cell-free extract and the activity of the glucose-6-phosphate dehydrogenase (G6PD) assignment. All the experiments were carried out independently in triplicate.

Disintegration methods

Bead mill

The microbial cells were mixed either with glass (diameter, 0.5 mm) or zirconia (diameter, 0.7 mm) beads and disintegrated using a BioSpec BeadBeater (model 1107900) under cooling on ice. The total time of disintegration was 3 min in different cycles (30 s or 1 min of disruption and 2 min of cooling or 3 min of continuous process). After the separation of beads by decantation, cell homogenates were centrifuged (6,500 rpm, 15 min, 4°C; Hettich Universal 16 Zentrifugen) and the supernatant was analyzed.

Sonication

Sonication was performed using a Torbeo Ultrasonic Processor (Fisher Scientific) device to provide continuous application of acoustic waves for 11 or 30 s. The sonication was then interrupted and the suspended cells cooled in an ice bath for 2 min, and the next sonication cycle was then performed. The total time of sonication was 1, 2, 3.5, or 5 min. The homogenate was centrifuged (6,500 rpm, 15 min, 4°C; Hettich Universal 16 Zentrifugen) and the supernatant analyzed.

Chemical disintegration

The sample of biomass was suspended in an appropriate water solution of detergents (Triton X-100, CTAB, Tween 80, SDS) and incubated with shaking in room temperature. Detergent concentrations were as follows: 0.1%, 0.25%, 0.5%, and 1% for R. gracilis; 0.5%, 1%, 1.5%, and 5% for P. citrinum and A. fumigatus. After the incubation period (5 or 20 min for yeast and 20 or 40 min for molds), the mixture was clarified by centrifugation (6,500 rpm, 15 min, 4°C; Hettich Universal 16 Zentrifugen) and the supernatant analyzed.

In the case of organic solvent treatment, microbial cells were suspended in 20 mL of Tris buffer (50 mmol/L, pH 7.5) and the mixture with the addition of 2 mL of toluene was shaken for 2 h; subsequently, the cells were separated by centrifugation and the cell-free extract was analyzed.

Osmotic shock

Microbial cells were suspended in 20 mL of hypertonic solution (50 mmol/L Tris-HCl buffer, pH 7.5, containing 10 mmol/L EDTA and 30% ( w/ v) sucrose) and gently shaken for 20 min. After that cell suspension was centrifuged and the pellet was disintegrated by suspending in 20 mL of 10 mmol/L MgCl ₂ over 20 min, the cells were removed by centrifugation and the supernatant was analyzed.

Analytical methods

Protein assay

Soluble protein concentrations in clarified supernatants were estimated by the Bradford method using bovine serum albumin as the standard (Bradford 1976).

Enzyme assay

The activity of the intracellular enzyme, glucose-6-phosphate dehydrogenase (E.C. 1.1.1.49), was determined by the method described by Bergmeyer ( 1983). Changes in absorption at 340 nm were monitored over a period of 10 min on UV/Vis Spectrometer (Varian Cary 100 Bio). Total activity of the crude extracts was given as the specific activity of the enzyme and was expressed in units per milligram of the total amount of proteins, where "U" is defined as 1 μmol NADPH formed per minute.

Results

To establish the most efficient method of fungal cell lysis, three morphologically different fungal species- A. fumigatus, P. citrinum, and Rhodothorula gracilis -were subjected to various disruption protocols. The applied procedures imply the following results.

Sonication

Ultrasonication is a common mechanical cell disruption method based on the high shear created by a high-frequency ultrasound (above 16 kHz). The level of released proteins and the activity of G6P dehydrogenase served as an indicator of the mildness of the process. In the case of the P. citrinum strain, an 11-s sonication cycle resulted in the highest concentration of the released proteins, but the level of specific activity of G6P dehydrogenase was the best for a longer sonication cycle, 30 s (Table 1 ). In contrast, the most suitable way for the disintegration of A. fumigatus cells was sonication with 11-s cycles and an overall operation time of 3.5 min. It resulted in a high level of released proteins and allowed obtaining high specific activity of G6P dehydrogenase in the crude extract (Table 1 ). Similarly, the same operating conditions (11-s cycles and 3.5 min of process time) were the most suitable for the disintegration of R. gracilis yeast (Table 1 ).

Table 1

Procedure

Assayed values

Penicillium citrinum

Aspergillus fumigatus

Rhodotorula gracillis

Protein concentration (μg/mL)

Specific enzyme activity of G6PDa (U/mg, ×10−3)

Protein concentration (μg/mL)

Specific enzyme activity of G6PDa (U/mg, ×10−3)

Protein concentration (μg/mL)

Specific enzyme activity of G6PDa (U/mg, ×10−3)

Sonication

Bead mill

Bead mill

The amount of proteins released from the cells of the Aspergillus strain was comparable to the values obtained by the sonication procedures. The short time of disintegration (30 s) and the use of smaller glass beads seemed to be optimal for allotted aims (Table 1 ). The most effective protocol for the disintegration of P. citrinum biomass seemed to be the procedure using a 30-s operating time and the use of 0.7-mm zirconium beads. In the case of Rhodotorula biomass, the level of obtained soluble proteins in the crude extracts disintegrated with zirconia beads was very low compared with the procedures in which glass beads of a smaller size were used. In turn, the highest specific activity of G6P dehydrogenase in the crude extract was achieved with the application of zirconia beads within the overall operating time of 3 min (Table 1 ).

Chemical treatment

The application of Triton X-100, which is a non-ionic type of detergent recommended for permeabilization and/or lysis of cell walls, was found to be ineffective for fungi (data not shown). In the case of P. citrinum, the activity of G6P dehydrogenase in the cell-free extracts was not found. The application of this detergent at a 5% concentration for the disintegration of A. fumigatus led to a very low level of specific activity of the model enzyme (1.46 ± 0.13 × 10 −5 U/mg of proteins). The procedure based on Tween 80 was more effective for the tested molds. The best results were obtained for P. citrinum (7.33 ± 0.27 × 10 −5 U/mg of proteins) when using 1.5% of Tween 80 for 40 min of treatment. On the other hand, for A. fumigatus, the G6P dehydrogenase activity was 3.8 ± 0.17 × 10 −4 U/mg of protein, with 0.5% of detergent concentration and 40 min of the process. Both non-ionic detergents were useless for R. gracilis. Increasing the detergent concentration (up to 5%) resulted in the release of very high levels of total proteins from the cells of the Penicillium and Aspergillus strains (up to 7.5 and 12.3 mg/mL, respectively). Unfortunately, only in the case of P. citrinum did the cell-free extract show the required specific activities of G6P dehydrogenase-3.44 ± 0.32 × 10 −5 U/mg of proteins (0.5%, 40 min) and 1.4 ± 0.09 × 10 −5 U/mg of proteins (1.5%, 40 min). CTAB disintegration of yeast cells resulted in a low level of total proteins released (data not shown), and the most effective procedure appeared to be with 0.1% of detergent solution. Extending the time of incubation of the cells with detergents (from 5 to 20 min) allowed increasing the value of specific activities of the model enzyme from 1.62 ± 0.56 × 10 −3 up to 2.23 ± 0.13 × 10 −3 U/mg of proteins. The effects of anionic detergents on the microorganisms were also investigated using SDS as a model. The procedures based on the application of 0.5% SDS solution for molds and 0.1% for yeasts allowed detecting the specific activities of the model dehydrogenase in crude extracts. In the case of P. citrinum, after 40 min of incubation, the value of specific activity was 2.5 ± 0.06 × 10 −4 U/mg of proteins, for A. fumigatus was 1.2 ± 0.08 × 10 −4 U/mg of proteins (20 min), and for R. gracilis was 4.04 ± 0.23 × 10 −3 U/mg of proteins (20 min). Also, the influence of toluene on the cohesion of the cell wall of the microorganisms was examined. The release of a very low amount of the proteins from the cells was observed, and there was no detectable activity of the model dehydrogenase in crude fungal extracts.

Osmotic shock

The disintegration of fungi with this method failed (data are not shown).

Discussion

The overriding purpose of this study was to set up unique, effective, and repetitive disruption protocols for particular fungal species. The tested fungi have been chosen because of their industrial and/or medical importance. Rhodotorula strains are known for the intracellular production of useful amino acid oxidases (Kuan et al. 2008) and β-carotene (Vijayalakshmi et al. 2001). Secondary metabolites produced inside the cells of A. fumigatus and P. citrinum are also of commercial interest (Du et al. 2010; Chen et al. 2011; Malmstrom et al. 2000; Lim et al. 2007; Singh et al. 2011). Additionally, molds like A. fumigatus are widely considered as a hazard contaminant of food and human pathogen (Debeaupuis et al. 1997; Denning 1998). Molecular methods of detecting fungal pathogen in clinical or food samples require simple and fast methods that sufficiently lyse fungal cells.

The fungal wall structure is highly dynamic, changing constantly during cell division, growth, and morphogenesis. The specific composition and mechanical properties of the cell wall are varied not only between genera but also within closely related species. Moreover, this protective layer could change with growth conditions and genetic modifications (Firon et al. 2004; Klis et al. 2006). Thus, in the case of the sonication methods, most of the ultrasound energy, which is absorbed by cell suspension, appeared as heat; hence, temperature control is crucial and obligatory. Besides the cell types, the appropriate time of exposure of the biological material to the ultrasound is also a critical parameter influencing the activity of the intracellular compounds. In the case of P. citrinum strain, the prolongation of sonication cycles from 11 to 30 s admittedly resulted in the decrease of the amount of released proteins, but allowed obtaining a higher level of specific activity of G6P dehydrogenase in the crude extract (Table 1 ), suggesting the existence of a lower thermal stress. In contradiction, for the A. fumigatus cells, the short period of sonication was appropriate (11-s cycles and overall operation time of 3.5 min), giving as well the extract with a high level of released proteins and a high specific activity of G6P dehydrogenase. The level of proteins released under variable conditions of ultrasound disruption procedures is much higher in the case of yeast cells than molds. This can be simply explained by the different strengths and structures of the fungal cell walls which comprised glycoproteins and polysaccharides, mainly glucan and chitin. Chitin has an enormous tensile strength and significantly contributes to the overall integrity of the cell wall. Chitin microfibrils account for only 1-2% of the yeast cell walls by dry weight, whereas the cell walls of filamentous fungi, such as Aspergillus, are reported to contain 10-20% chitin (Bowman and Free 2006). Additionally, G6P dehydrogenases derived from A. fumigatus and R. gracilis seemed to be more sensitive to increasing temperature, which made prolongation of the disruption time useless because it caused the significant decrease of the specific activity of the examined model enzyme in the crude extract. The observed inactivation of dehydrogenase might also derive from ionization and subsequent free radical formation (Gogate and Kabadi 2009). Application of the bead mill turned out to be effective in the case of the destruction of Penicillium cells. Although the amount of the released proteins was lower, the specific activities of the model enzyme were surprisingly high (up to 20 ± 1.97 × 10 −3 U/mg of proteins). However, in the case of Rhodotorula biomass, the kind of beads and their size were critical parameters, but the results were still unsatisfactory compared with those discussed previously, the sonication procedure. The bead mill is reported to be an efficient technique for rupturing yeast and mold cells compared with its effectiveness toward bacteria (Middelberg 1995). Many operating parameters of milling were used, the most important of which is the design of the stirrer, geometry of the grinding chamber, size of beads, and the temperature. In our case, the disruption method based on the application of BeadBeater® was effective only in the case of P. citrinum. Both A. fumigatus and R. gracilis cells were found to be resistant to milling disruption; thus, the sonication procedures are recommended in these cases. Finally, the chemical treatment led to unsatisfactory results in every experimental attempt. Admittedly, procedures based on detergent treatment, applied for the disintegration of Aspergillus and Penicillum cells, resulted in a high level of released proteins with low or no detectable activity of G6P dehydrogenase in cell-free extracts. The examined detergents inhibited the activity of G6P dehydrogenase and/or forced the conformational changes in the enzyme structure, which influenced the stability of fungal dehydrogenase. In the case of charged detergents, there is also the possibility of a destructive impact which comes from the ionic interaction between enzyme and detergent residues.

Non-mechanical cell disruption methods require less energy, although some of them resulted in the release of side products. However, their application is often limited to processes of a small scale, owing to restrictions of process economics or efficiency. Consequently, they have found limited commercial application.

To sum up, the undertaken efforts allowed elaborating protocols of the cells wall disruption for the examined fungi. The mechanical methods appeared to be the most effective for the disintegration of yeast, R. gracilis, and filamentous fungi, A. fumigatus and P. citrinum. Ultrasonication and bead milling led to enzymatically active cell-free extracts, which can be a starting point for the isolation and purification of intracellular components of interest.

Acknowledgments

This work was financed from Project "Biotransformations for pharmaceutical and cosmetics industry" no. POIG.01.03.01-00-158/09-05, part-financed by the European Union within the European Regional Development Fund for the Innovative Economy.

Open Access

This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited.

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Comparative study of fungal cell disruption-scope and limitations of the methods

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Folia Microbiol (Praha). 2011; 56(5): 469-475. Simple and effective protocols of cell wall disruption were elaborated for tested fungal strains: Penicillium citrinum, Aspergillus fumigatus, Rhodotorula gracilis. Several techniques of cell wall disintegration were studied, including ultrasound disintegration, homogenization in bead mill, application of chemicals of various types, and osmotic shock.

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Vissīkākās baktērijas šūnas daļiņa novērojot ar krioelektronmikroskopu.

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Vissīkākās baktērijas šūnas daļiņa novērojot ar krioelektronmikroskopu.

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Vienšūņa Cryptosporidium spp. izplatība un invāziju veicinošie faktori liellopos Latvijā

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Cryptosporidium spp. ir nozīmīgs, diareju izraisošais patogēns, kura invāziju ietekmējoši faktori un ekstensitāte liellopos ir maz pētīti Latvijas teritorijā. Bakalaura darba ietvaros, laika periodā no 2017. gada rudens līdz 2018. gada pavasarim, tika analizēti 135 paraugi no septiņām saimniecībām,…

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Cilmes šūnas:

1.  Ja šūna ir ievainota vai tai ir DNS defekti, tā pašiznīcinās, lai neietekmētu citas šūnas.

2.  Cilmes šūnas ir totipotentas. Tas nozīmē, ka tās var pārvērsties par jebkuru ķermenim nepieciešamo šūnu.

3. Traumu/bojājumu gadījumos, ķermeņa šūnas spēj kļūt par „audu cilmes šūnām”, kuras ir spējīgas atjaunot bojātos audus.

4.  Savukārt veidojoties vēža šūnām - cilmes šūnas nevis atjauno audus, bet sāk nekontrolēti dalīties un veidot audzēju.

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1. KODOLS - Satur iedzimtības informāciju. Regulē šūnas darbību. Kodoliņā veidojas ribosomu sastāvdaļas, kas caur kodola porām nonāk citoplazmā.
2. CITOPLAZMA - Nodrošina vielmaiņu šūnā un mijiedarbību starp organoīdiem, tā aizņem 80% no šunas.
3. PLAZMATISKĀ MEMBRĀNA - Nodrošina vielu apmaiņu starp citoplazmu un vidi. Uztver izmaiņas apkārtējā vidē.
4. RIBOSOMA - Sintezē olbaltumvielas.
5. ENDOPLAZMATISKAIS TĪKLS - Graudainais ET veic olbaltum- vielu sintēzi, pārveidošanu un transportu. Gludais ET sintezē lipīdus.
6. GOLDŽI KOMPLEKSS - Uzkrāj ET sintezētās vielas un transportē tās pūslīšu sastāvā. Pūslīši izdala vielas ārpus šūnas vai veido lizosomas.
7. LIZOSOMA - Dažādu vielu un novecojošu šūnas struktūru sadalīšana.
8. ŠUNAPVALKS - Mehāniski balsta un aizsargā šūnu, nodrošina vielu apmaiņu starp šūnām.
9. HLOROPLASTS - Dod šūnai zaļo krāsu, veic fotosintēzi, pārvēršot gaismas enerģiju par ATP (adenozīntrifosfāts) saišu enerģiju. Šo enerģiju patērē, lai no neorganiskajām vielām (ogļskābās gāzes un ūdens) ražotu organiskās vielas.
10. MITOHONDRIJS - Skābekļa klātbūtnē oksidējoties organiskiem savienojumiem, atbrīvojas enerģija, kas tiek izmantota ATP sintēzei.
11. VAKUOLA - Šūnsulā uzkrāj vielmaiņas produktus, regulē spiedienu šūnā. Galvenā nozīme ūdens uzsūkšanā šūnā.

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Šobrīd, kad vārds "vīruss" skan visapkārt, ir īstais brīdis atgādināt, ka tie sastopami ne tikai cilvēkiem, dzīvniekiem, datoriem, bet arī augiem. Ir zināms apmēram 1000 dažādu vīrusu, kas izraisa augu slimības. Tās ir grūti atšķirt no barības elementu trūkuma, ārstēšana nav iespējama.

Vīrusi ir plaši izplatīti dekoratīvajiem augiem - asterēm, begonijām, dālijām, gerberām, gladiolām, krizantēmām, pelargonijām u. c. Tie ir sastopami arī ekonomiski nozīmīgos dārzeņos un augļaugos - tomātos, paprikā, lapu salātos, kartupeļos, avenēs, kā arī daudzās nezālēs.

No kā sastāv vīrusi? Vīrusiem nav tipiskas šūnas uzbūves, jo tipiskām šūnām ir šūnapvalks, kodols ar DNS, citoplazma, vakuola un dažādi organoīdi. Vīrusi sastāv no kapsīda, olbaltumvielu apvalka un ribonukleīnskābes (RNS), vai retāk dezoksiribonukleīnskābes (DNS). DNS un RNS ir ģenētiskās informācijas glabātājs un nodrošina jaunu nukleīnskābju sintēzi. Lai vīrusi spētu funkcionēt un vairotos, tiem nepieciešams atrasties dzīvā organismā. Vīrusi ir šūnu parazīti - vīruss pilnībā izmanto auga resursus, lai izdzīvotu, nedodot nekādu labumu augam. Vīrusi nespēj ilgstoši izdzīvot (no 15 min. līdz 24 h), ja neatrodas dzīvā organismā.

Kā atpazīt vīrusu? Simptomi var izpausties lokāli, uz kādas konkrētas auga daļas, vai sistēmiski, kas skar visas augu daļas. Visbiežāk simptomi ir neregulāra lapu dzeltēšana vai dažādi plankumi uz lapām (2. att.) , kā arī lapām novērojama deformācija (3. att) . Ziediem arī novērojama deformācija un krāsas maiņa (4. att.) . Daļa vīrusu izraisa arī augu atpalicību augumā.

Pēc simptomiem reti iespējams identificēt, ka tā ir vīrusa izraisīta slimība, tāpēc jāveic analīzes laboratorijā. Šādas analīzes ir iespējams veikt Valsts augu aizsardzības dienesta laboratorijā.

Vīrusu attīstības cikls. Lielai daļai vīrusu ir specifisks saimniekaugs, tas nozīmē, ka tie spēj inficēt tikai noteiktus augus. Vīrusa attīstība sākas ar vīrusa iekļūšanu auga šūnā (4. att.)[1]. Vīrusu var pārnest no viena auga uz otru augu tikai ar auga sulu vai ūdens pilienu, kurā atrodas vīruss. Ar vīrusu nevar inficēties, ja augi ar lapām vai stumbriem vienkārši saskaras kopā bez šķidrumu apmaiņas. Pēc vīrusa iekļūšanas šūnā tas noārda ārējo apvalku. Pēc ārējā apvalka noārdīšanās vīrusa nukleīnskābe (ģenētiskais materiāls) brīvi atrodas šūnas citoplazmā, vēlāk vīruss ieiet šūnas kodolā. Pēc tam atkarībā no nukleīnskābes veida šūnu organoīdi tiek izmantoti vīrusa genoma kopēšanai un jaunu vīrusu sintezēšanai, tādējādi traucējot auga augšanu un attīstību. Lai vīruss pilnīgi inficētu augu, tam jāiekļūst auga vadaudu sistēmā. Iekļūstot tajā, vīruss izplatās pa visu augu. Atkarībā no vīrusa augu sugas un vides apstākļiem pilnīgai auga infekcijai nepieciešamais laiks var atšķirties no dažām dienām līdz pat dažām nedēļām. Vīrusa attīstības cikls beidzas, kad jaunie izveidotie vīrusi pārvietojas uz neinficētām augu šūnām.

Vīrusa izplatība. Vīrusiem ir vairākas iespējas, kā izplatīties. Vīrusus pārvieto ar inficētiem augiem vai augu daļām (sēklām un putekšņiem), piemēram, no kaimiņvalstīm ievedot inficētus plūmju potzarus ar plūmju virālajām bakām (šarka). Šādiem potzariem augot, vīruss izplatās pa visu koku.

Vīrusi pārvietojas mehāniski, piemēram, ar dārza šķērēm nogriežot inficētu zaru vai ziedu, un pēc tam ar tām pašām šķērēm nogriežot citam augam kādu daļu, tādējādi inficējot nākamo augu, pārnesot auga sulu, kurā atrodas vīruss. Augļu dārzā, ja ir aizdomas par inficētu koku, pēc šāda koka apgriešanas jādezinficē šķēres, vai arī šo koku var apgriezt pēdējo. Uz instrumentiem vīrus ilgstoši nespēj izdzīvot. Tulpēm drošāk un vienkāršāk noziedējušos ziedus ir nolauzt nevis nogriezt. Tāpat tomātiem un gurķiem lapas drošāk ir lauzt nevis griezt.

Vīrusi pārvietojas ar kukaiņiem un ērcēm. Visnozīmīgākās ir laputis, retāk tripši, mīkstblaktis un cikādes (6. un 7. att.). Ir arī atsevišķas nematodes, kas pārnēsā vīrusus. Kukaiņiem sūcot sulu, pie viņu mutes orgāniem paliek augu sula, kurā atrodas vīruss, pēc tam, kukaiņiem migrējot uz citu augu un sūcot sulu, tiek inficēts nākamais augs.

Svarīgi pēc augsnes apstrādes notīrīt augsnes apstrādes agregātus no augsnes, jo ar augsni iespējams pārnest nematodes no viena lauka uz citu.

Ierobežošana. Augiem atšķirībā no dzīvniekiem un cilvēkiem nav imūnsistēmas, kas spēj cīnīties ar vīrusu. Augiem vīrusu infekcijas var ierobežot tikai profilaktiski - izmantojot veselu stādāmo materiālu, ierobežojot kaitēkļus, īpaši tos, kas sūc augu sulu. Svarīgi ievērot arī sanitārās prasības dārzā un lietot tīrus darba instrumentus. Ar vīrusu inficēts augs jāiznīcina, atveseļot nav iespējams. Atstājot šādu augu dārzā, pastāv risks, ka pārējie augi arī var tikt inficēti.
Edgars Cirša,
LLKC Kuldīgas konsultāciju biroja augkopības konsultants
[1] https://www.helsinki.fi/en/researchgroups/plant-pathology-and-virology
2 https://drecampbell.com/types-of-plant-diseases-how-to-treat-naturally/
3 https://www.colonialwilliamsburg.org/learn/deep-dives/5-truths-about-tulips/|
4 https://courses.lumenlearning.com/microbiology/chapter/the-viral-life-cycle/

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Šobrīd, kad vārds "vīruss" skan visapkārt, ir īstais brīdis atgādināt, ka tie sastopami ne tikai cilvēkiem, dzīvniekiem, datoriem, bet arī augiem. Ir zināms apmēram 1000 dažādu vīrusu, kas izraisa augu slimības. Tās ir grūti atšķirt no barības elementu trūkuma, ārstēšana nav iespējama. Vīrusi ir plaši izplatīti dekoratīvajiem augiem - asterēm, begonijām, dālijām, gerberām, gladiolām, krizantēmām, pelargonijām u.