J. Brčák

Mycoplasma-like microorganism and virus particles in the leafhopperJavesella pellucida (F.) transmitting the oat sterile dwarf disease

Na ultratenkých řezech buňkami střevního epitelu křísůJavesella pellucida (F.), přenášejících sterilní zakrslost ovsa (považovanou za virózu), byly pozorovány jednak virové částice uložené v cytoplasmě v trubicovitých strukturách, jodnak mikroorganismus, který je podle tvaru, velikosti a vnitřní stavby totožný s druhy roduMycoplasma nebo se zástupci skupiny PLT (psittakóza, lymfogranulom, trachom). Jde o pravděpodobného původce sterilní zakrslosti ovsa.AbstractНа ультратопких срезах клетками кишечного эпителия цикадокJ. pellucida (F.)—переносчиков стерильной карликовости овса, считаемой вирусным заболсванием, наблюдались, во-первых, вирусные частицы, расположенные в цитоплазме в тубулярных структурах, а во-вторых, микроорганизмы тождественные по форме, величине и внутренней структуре с видамиMycoplasma или с группой PLT (psittakosisslymfogranulomrachom.). Вероятно они являются возбудителями заболевания.

Virus origin of the oat sterile dwarf disease

AbstractVirus particles (approximately 73 nm in diam.) usually showing an inner capside (45 nm in diam.) and similar to diplornaviruses, esp. reoviruses, were found in some cells of enations inAvena sativa andArrhenatherum elatius leaves infected with the oat sterile dwarf disease (OSDD). (The same virus particles were described by the authors in 1966 in the leafhopper vector.) Mycoplasma-like microorganisms found in1969 in the OSDD leafhopper vector were absent in OSDD infected plants. Tetracycline did not affect symptom development in plants and did not alter the infectivity of the vector.Therefore, OSDD is apparently of virus origin; mycoplasmas-like bodies found formerly in the OSDD vector are probably not involved in OSDD etiology.

Mycoplasmas in apple trees infected with the proliferation disease

A mycoplasma-like microorganism was identified on electron micrographs of ultrathin sections of roots and abnormal underground sprouts growing from roots of young apple trees artificially infected with the proliferation disease. Specimens taken in November, contained mycoplasmas at various stages of reproduction in sieve tubes of the host. Mycoplasma-like bodies occurred especially in abnormal underground sprouts, and rarely also in lateral roots.

Invaginations in plant cell protoplasts containing mycoplasma-like bodies (MLO)

MLO containing invaginations were found in protoplasts of phloem parenchyma cells in symptomless young leaves ofRibes houghtonianumJancz. infected with a yellows disease. The invaginations originate between the cell wall and plasmalemma, usually at plasmodesmata, and change apparently into superficial vesicles in the protoplast; they are entirely or partially limited by host plasmalemma. The formations mentioned occur in parenchyma cells which contain normal organelles. Sometimes they are divided by a smooth membrane system enclosing MLO. Besides MLO the invaginations contain in some cases slimy fibrils resembling the P-protein in sieve tubes. The MLO bodies seen in invaginations have usually a diameter of 50–250 nm and their plasmalemma (unit membrane) is identical with the plasmalemma of MLO bodies occurring in sieve tubes. However, only few MLO bodies in invaginations are electron dense, so that they resemble naturally degenerated forms of MLO. Similar MLO containing invaginations were formerly described from some leafhoppers transmitting MLO.AbstractV lýkové části cévního svazku bezpříznakých mladých listů rybízuRibes houghtonianumJancz., nakaženého žloutenkovou chorobou „plnokvětostí”, byly v parenchymových buňkách zjištěny vchlípeniny protoplastu obsahující MLO. Tyto invaginace vznikají mezi buněčnou stěnou a plasmalemou obvykle u plasmodesmů. Z invaginací zřejmě vznikají vesikuly v povrchu protoplastu obsahující MLO; jsou úplně nebo jen částečně uzavřeny plasmalemou hostitele. Tyto invaginace a vesikuly se vyskytují v parenchymových buňkách obsahujících normální organely a nékdy jsou rozčleněny systémem hladkých membrán, v němž bývá též uzavřen jejich obsah MLO. Uvedené útvary někdy obsahují kromě MLO též fibrilární hmotu, která připomíná P-protein v sítkovicích. Tělíska MLO v invaginacích mají nejčastěji průměr 50–250 nm, jejich plasmalema je stejná jako u tělísek MLO v sítkovicích; pouze některá tělíska mají hustší obsah, takže připomínají přirozeně degenerované formy MLO. Podobné invaginace s MLO jsou známy z křísů přenášejících MLO.

Computer aided evaluation of differences in host reactions between isolates of turnip mosaic virus fromSisymbrium loeselii

Twenty three isolates of turnip mosaic virus (TuMV) obtained from spontaneously infected plants ofSiaymbrivm loeaeliiJUSL. were serologically related, but differed in reactions of eleven host plants. Susceptibility and sensitivity of each host for each TuMV isolate were classified by one of six degrees (0 to 5) respectively. Similarities of isolates (as compared in 253 pairs) were evaluated by means of a computer; for this purpose the source program MINDIF has been elaborated using the universal program language Algol 60. A table of differences between isolates was obtained and distribution of isolate pairs dependent upon the difference values was stated. The fitness of hosts for differentiating TuMV isolates was ascertained quantitatively. No relation of isolate similarity to geographical indices could be established.

A Prague isolate of wisteria vein mosaic virus

An isolate of wisteria vein mosaic virus (WVMV) obtained fromWisteria sinensis in Prague resembled in its properties WVMV isolates described in Italy and Holland.Nicotiana megalosiphon is reported as a new host of WVMV. Other known host plants showed reactions similar to those described formerly. The incubation period extended in some hosts up to two or four weeks. Pea plants showed symptoms within five to seven days. Species ofApium, Brassica,Datura and others were not susceptible. TIP of Prague isolate of WVMV was 61 °C, at a dilution 1: 5000 47% of plants were infected, and 48 h > LIV > 28 h. Modal particle length was 743 nm. Massive granular inclusions were seen in pea epidermal cells, usually adhering to nuclei that did not show alterations. No serological relation to turnip mosaic virus could be established.

Tubular structures associated with mycoplasma in proliferation infected apple trees

Tubular structures showing honeycomb-like appearance in cross sections were found in mycoplasma invaded sievetube cells of abnormal sprouts of apple trees infected with the proliferation disease. The nature of tubular structures is unknown. There is a striking similarity (or identity) with the tubular structures described formerly in HEp-2 cells which were established from human carcinoma of the larynx.

Czech and scandinavian isolates resembling dandelion yellow mosaic virus

Virus isolates resembling the dandelion yellow mosaic virus (synonym: lettuce necrosis virus) were obtained from dandelion plants in twenty five localities of Bohemia and also of Norway, Sweden and Finland. All isolates were sap transmissible merely to lettuce, but some of them also toChenopodium quinoa; other test plants could not be infected. Attempted serological and biological identification of the isolates with some viruses presumed to be able to infect spontaneously dandelion plants have failed.

On the specific difference in the local necrotic response to infection by tobacco mosaic and cabbage black ringspot viruses in tobaccos

Dědičně faktory podmiňující v rostlině schopnost reagovat na infekci virem mozaiky tabáku (Nicotiana virus 1) a virem černé kroužkovitosti zeli (Brassica virus 1) lokálními nekrotickými lézemi, resp. systémovoù infekcí, jsou u těchto dvou virů Jen zdánlivě v inversní závislosti. Nicotiana tabacum var. Xanthi-nc, který získal nekrotický faktor z N. glutinosa, má ještě nekrotický faktor pro infekci virem černé kroužkovitosti zelí.AbstractНаследственные факторы, обусловливающие в растении способностъ реагировать на инфекцию вирусом мозаики табака (Nicotiana virus1) и вирусом черной пятнистости канусты (Brassica virus 1) местными некрозами или обшим заболеванием, находятся липгь мнимо у этих двух вирусов в инверсной зависимости.Nicotiana tabacum var. Xanthi-nc, получивнший некротический фактор изN. Glutinosa, имеет еще и некротический фактор для заболевания вирусом черной пятнистости капусты.

Preventive effect of inhibitors from potato leaves on local infection with virus X

Substances inhibiting local infection with virus X were isolated from leaves of potato cultivars Saphir, Saco, and Blaník by means of ultracentifugation and were concentrated with ammonium sulphate. These inhibitors were effective if rubbed into leaves of some host plants at least 2–4 days prior to infection without using any abrasives.AbstractZ listů odrůd bramboru Saphir, Saco a Blaník, byly získány ultracentrifugací a koncentrováním síranem amonným látky, které inhibovaly lokální infekei X-virem bramboru, jestliže byly vetřeny bez abrasiva do listů indikátorových rostlin aspoň 2–4 dny před infekeí.AbstractИз листьев картофеля сортов Сафир, Сако и Бланик получены ультрацентрифугированием и концентрированием сернокислым аммонием вещества ингибирующие местную инфекцию X-вирусом картофеля после втирания их без абразива в листья индикаторных растений за 2–4 дня перед инфекцией.