Yellow Strain Research Articles

The use of a line of hamster kidney cells (BHK 21) for growth of arthropod-borne viruses

1. 1) Group A and B arthropod-borne viruses were tested for their ability to multiply, produce cytopathic effect and form plaques in a line of baby-hamster kidney cells (BHK 21). 2. 2) VEE, Mayaro, SLE and Ilhéus viruses multiplied well, produced a cytopathic effect and formed plaques. Mayaro formed triangular, crescentic or irregular (cirriform) plaques. 3. 3) Yellow fever virus strains FN and 17D multiplied, but cytopathic effect and plaque formation were variable. The lack of cytopathic effect was correlated with production of interferon effective against an attenuated strain of foot-and-mouth disease virus. 4. 4) BHK 21 cells were used for isolation, identification and serum neutralization tests in an outbreak of VEE in Venezuela. 5. 5) It is suggested that BHK 21 cells would be suitable for virus isolation studies with the faster growing, arthropod-borne viruses, which do not produce interferon.

Crystalline inclusions in Colladonus montanus (Van Duzee), a vector of Western X-disease virus

Needlelike crystals, ranging in size from 3 μ by 69 μ to 20 μ by 295 μ, were found in the intestinal tracts of Colladonus montanus (Van Duzee) feeding on celery ( Apium graveolens var. ‘Utah Green’) plants infected with the peach yellow leafroll strain of Western X-disease virus. Crystals were not found in insects propagated on healthy plants, but were present in a high proportion of insects which had fed on diseased plants for 30 or more days. When insects from a diseased stock colony with a high incidence of crystals were transferred to healthy plants, the frequency of individuals with crystals decreased. Crystals possessed the properties of high bire-fringence. They were readily soluble in 0.01 N NaOH as well as in 0.01 M sodium carbonate (pH 10.2) and 0.01 M potassium phosphate (pH 8.0) buffers; but stable in 0.01 N HCl. They dissolved slowly in distilled water. The nature of the crystals is not yet known.

THE INCREASE IN CONCENTRATION OF TWO STRAINS OF POTATO VIRUS X IN FLOATING LEAF DISCS

Increases in concentration of two antigenically similar strains (ringspot and yellow) of potato virus X (PVX) in Nicotiana tabacum L. vars. Samsun and Havana 38 and in Nicotiana rustica L. were determined serologically and by local lesion assay. In discs of inoculated leaf tissue floating on Hoagland's solution the rate of increase was greatest at 16° and 20 °C. In Samsun the optimum temperature for the increase in virus concentration was lower for the yellow strain than the ringspot strain. A close correlation between the assay procedures indicated that, as the temperature increased above the optimum for virus increase, either virus synthesis was being inhibited or virus was being denatured. No differences were found where 8- and 16-hour photoperiods were compared to determine their effect on virus increase at 20 °C. Virus concentrations in Samsun and Havana 38 were similar when determined under similar conditions. Concentrations in N. rustica were appreciably higher. In both Nicotiana species the concentration of the yellow strain at any time after inoculation was lower than that of the ringspot strain.

A plant virus lethal to its insect vector

The peach yellow leaf roll strain of Western X-disease virus was shown to cause the premature death of its leafhopper vector, Colladonus montanus. Celery was used as virus source plants and as test plants. In one type of experiment, leafhoppers from a single colony were divided into two equal groups. One group was caged on diseased celery for 21 days while the control group fed only on healthy celery. Later, 15 insects from each group were tested singly for virus transmission and longevity. Twelve leafhoppers which transmitted virus had a mean longevity of 38 days compared to 82 days for the noninfective controls. The remaining insects from each of the two main groups were tested in groups of 10. The mean longevity of these infective and noninfective groups was 24 and 51 days, respectively. In other experiments all leafhoppers were caged on diseased plants and were subsequently tested individually for virus transmission and longevity. In fourteen such experiments the mean longevity of 116 leafhoppers that transmitted virus was 20 days compared to 51 days for the 64 nontransmitting individuals. These results indicate that the virus itself shortens the life of leafhoppers which acquire it and that the differences in longevity cannot be accounted for on the basis of altered physiology of diseased plants. This appears to be the first record of a virus that eventually kills its insect vector, and it adds to the plausibility of the theory that plant viruses may have evolved from arthropod viruses.

A yellow strain of potato virus X

The isolation of a previously undescribed yellow strain of potato virus X is reported. The strain incites bright yellow non-necrotic lesions on the inoculated leaves ofN. rustica. On certain other hosts, it also reacts differently from previously described virus X strains. The reaction of certain potato test varieties, the thermal inactivation point, the passage through stem sections of the immune variety Saco and USDA Seedling 41956, and some serological and cross protection relationships are described. It is concluded that the yellow strain is sufficiently different from other reported strains of potato virus X to warrant a separate designation.

SOME EFFECTS OF CHANGING TEMPERATURE AND OF VIRUS INHIBITORS ON INFECTION BY CUCUMBER MOSAIC VIRUS

Whereas the spinach strain of cucumber mosaic virus fails to multiply and cause symptoms in tobacco plants kept above 30° C., the yellow strain infects at 36° C. and causes more severe symptoms than at 20° C. Increasing the temperature up to 28° C. increases the initial rate at which the spinach strain multiplies, but the virus later reaches much higher concentrations in leaves at lower temperatures, presumably because it is rapidly inactivated at 28° C. Exposing inoculated plants to 36° C. for 6 hr. decreases the number of infections by the spinach strain when the exposure starts within 6 hr. of inoculation, but not afterwards.Pancreatic ribonuclease inhibits infections by strains of cucumber mosaic virus; inhibition is greatest when the enzyme is present in the inoculum, and when applied to inoculated leaves its effect decreases rapidly with increasing time after inoculation.Infection by and the multiplication of strains of cucumber mosaic virus in tobacco are only slightly affected by thiouracil and greatly by azaguanine, whereas strains of tobacco mosaic virus are inhibited much more by thiouracil than by azaguanine. Like tobacco mosaic virus, cucumber mosaic virus multiplies more when inoculated leaves are floated in nutrient solutions than in water, but unlike tobacco mosaic virus, its multiplication is not inhibited by thiouracil more in nutrient solutions than in water.

TWO ATTEMPTS UPON IMPROVING AN INDUSTRIAL STRAIN OF ASPERGILLUS ORYZAE THROUGH SOMATIC RECOMBINATION AND POLYPLOIDIZATION

1.Improvement of kojic acid producibility through somatic recombination was attempted with the following results:(1) One white leucineless strong producer and three yellow lysineless weak producers were recovered from a heterozygous diploid which was produced between a white leucineless weak producer and a yellow lysineless strong producer.(2) One of the segregants obtained from the above mentioned diploid strain produced about fourty percent larger amount of kojic acid than the parental producer, yellow lysineless strain.(3) In general, the breeding effect through this process did not turn out to be so significant as expected.2. Protease activity of three haploid, three diploid, one triploid, and one tetraploid strains were compared by wheat bran koji method, with the result that the protease activity of two diploid and one tetraploid strains was significantly higher than any of the haploid ones.

Feijoeiro manteiga, planta-teste para os vírus de vira-cabeça e da necrose branca do fumo

Entre cêrca de 200 variedades de feijoeiro ensaiadas, a Manteiga foi mais sensitiva aos vírus de vira-cabeça e da necrose branca, formando, nas fôlhas primárias, lesões locais adequadas para contagens. Com o vírus de vira-cabeça as lesões locais apareceram de 3 -6 dias após as inoculações, sob a forma de manchas cloróticas, às vezes com anéis necróticos; com o vírus da necrose branca as lesões se manifestaram em 1 - 4 dias, sob a forma de pontuações necróticas, pequenos anéis necróticos ou, em casos de certas estirpes do vírus, como pintas cloróticas. Feijoeiros com as fôlhas primárias tendo 2/3 de sua expansão ou mais desenvolvidas deram melhores resultados para o vírus de vira-cabeça; para o vírus da necrose branca os melhores resultados foram obtidos com fôlhas que tinham 2/3 ou ligeiramente menos de sua expansão total. O vírus de vira-cabeça não se tornou sistêmico em plantas inoculadas mecanicamente. A maioria das estirpes do vírus da necrose branca também não se tornou sistêmica em feijoeiros inoculados mecanicamente. Uma estirpe amarela deste tem a capacidade de se tornar sistêmica em feijoeiros sob determinadas condições. O sulfito de sódio em solução 0,0125 M, usado na extração do inóculo, aumentou ligeiramente o número de lesões formadas nas fôlhas do feijoeiro Manteiga pelo vírus de vira-cabeça; aumento consideravelmente maior foi obtido com a extração em presença de búfer de fosfato 0,1 M com pH 7, sendo êsse efeito atribuído a um aumento da sensitividade da planta-teste. A mistura de ambos causou aumento igual ou ligeiramente menor que o búfer só. Para o vírus da necrose branca a presença de sulfito de sódio 0,0125 M durante a extração aumentou consideravelmente o número de lesões, sendo esse efeito atribuído à diminuição na perda de atividade do vírus, devida à oxidação; o búfer sozinho ocasionou pequeno aumento em comparação com a testemunha, mas a mistura de búfer e sulfito de sódio deu o maior aumento.

Infection of Nicotiana glutinosa L. following injection of two strains of tobacco mosaic virus into a single cell

When a mixture of the ordinary strain and the yellow aucuba strain of tobacco mosaic virus was injected into a single hair cell of a seedling leaf of Nicotiana glutinosa L., either or both strains were subsequently detected in the lesion. Of the 20 lesions examined, the ordinary strain alone was found in 14 lesions, the yellow aucuba strain alone in 1 lesion, and both strains in 5 lesions. With a single exception, lesions have appeared only on leaves on which the inoculated hair remained alive for at least one day.

Application of chromatography. XXX. Studies on tryptophan metabolism in the culture of Eremothecium ashbyii.

In isolating a green fluorescent substance (G compound) from the mycelium of Er. ashbyii, yellow crystals, m.p. 223∼224°(decomp.), [α]20D-43.2°, were also separated and this substance was established as l-3-hydroxykynurenine. Study of the mycelium and broth of Er. ashbyii by two-dimentional paper chromatography detected only tryptophan and l-hydroxykynurenine as amino acid of tryptophan series, kynurenine being never detected. The two compounds were found from a comparatively early stage of the culture and they were readily distinguished by the color reaction with p-dimethy1-aminobenzaldehyde (Ehrlich reagent). Formation of riboflavin, l-hydroxykynurenine, and nicotinic acid was also investigated at intervals during the culture and it was found that riboflavin increased in proportion to the increase of l-hydroxykynurenine, but the formation of nicotinic acid factor seemed to have no quantitative relation to them. A leuco strain of Er. ashbyii obtained by successive culture of the yellow strain was also cultivated on the same medium and it was found that in addition to a slightly smaller production of the mycelium, the production of riboflavin and l-hydroxykynurenine was extremely low, compared with their production in the yellow strain. From such a fact it was presumed that the metabolism of kynurenine to l-hydroxykynurenine in the yellow strain is very active and that this oxidative process in the living body requires a large quantity of riboflavin.

Alterations in carotenoid synthesis accompanying mutation in Corynebacterium michiganense.

SUMMARY: Colour Mutants Of The Tomato Pathogen, Corynebacterium Michiganense, Provided An Opportunity To Determine The Nature Of This Micro-Organism'S Pigments, And The Effect Of Mutation And Nutrition Thereon. The Major Pigments Of C. Michiganense Are Carotenoids. The Parent And Mutant Strains Show Distinct Qualitative Differences In Pigment Synthesis. The Naturally Occurring Yellow Parent Type Produces Cryptoxanthin And Lycopene. A pink mutant forms lycopene and spirilloxanthin. A red back-mutant produces only lycopene. An orange mutant synthesizes cryptoxanthin, β-carotene and canthaxanthin. Carotenoids were not detected in the colourless mutants. Carotenoid synthesis in the yellow strain of C. michiganense is affected by thiamine in a manner similar to that previously described for C. poinsettiae: cryptoxanthin and lycopene are synthesized only at relatively high thiamine concentrations. The formation of lycopene, relative to spirilloxanthin, in the pink mutant is favoured by high thiamine concentrations. Similarly, the red strain forms appreciably more lycopene at higher thiamine concentrations than at lower. The formation of carotenoids in the orange strain appears not to be influenced by external thiamine concentration, possibly because this culture synthesizes an excess of the vitamin. No other nutritional factor which was examined caused detectable alterations in colour of the cells.

Some Characteristics of the Wheat Streak-Mosaic Virus and Disease

In the present study wheat plants of varying ages raised in the same greenhouse environment were inoculated by a carborundum rubbing method (6) with a 1 to 5 dilution of the yellow strain of wheat streakmosaic virus. Three trials were completed in which two varieties, Westar and Marquillo-Oro X Pawnee Sel. No. 462666 were used. The results are presented in Table 1. Plants inoculated at the early 2-leaf stage were either less susceptible or more probably were more difficult to infect by the technique used than when inoculated later. Only 16 percent of all such plants became diseased. However, these were very susceptible, being severely stunted and having severe mosaic symptoms. The incubation period was often more than 7 days and sometimes as long as 10 days. By contrast, when plants were inoculated from the 3-leaf stage to the 3-4-tiller stage symptoms were always severe and all plants were infected. Incubation periods were from 7 to 8 days. This compared favorably with the data of Sill and Fellows (8). Older plants (4-6 tillers and 6-8 tillers) gave a more erratic response to inoculation. A small percentage of the plants escaped infec-

STUDIES ON VARIATION IN PATHOGENICITY IN LEAF RUST OF WHEAT, PUCCINIA TRITICINA ERIKSS.

In experiments designed to clarify the causes of the pathogenic changes that have recently been encountered in leaf rust of wheat, two factors were given consideration, (1) the possibility that nuclear exchanges might occur between the mycelia of different races in the uredial stage, and (2) the possible role of Thalictrum species in originating new rust strains. Infection studies with mixtures of races 9 and 15 and mixtures of races 5 and 9 did not produce any evidence that these races could interchange nuclei and thus initiate new pathogenic strains of leaf rust.In greenhouse infection tests with native Thalictrum spp., aecia were produced on T. dasycarpum, pycnia only on T. dioicum and T. polygamum, while no infection of T. venulosum took place. In similar tests with the introduced species T. glaucum and T. dipterocarpum, abundant production of aecia occurred on both species. In out-of-doors inoculation tests with T. dasycarpum and T. venulosum, no infection of these two species took place, whereas, under the same conditions, heavy aecial production occurred on the introduced species T. glaucum.Selfing studies in which Thalictrum glaucum was infected with known physiologic races have indicated that some races of leaf rust are homozygous, and others heterozygous for pathogenic characters. A culture of race 5 appeared to be homozygous, whereas a culture of race 3 was heterozygous, giving rise to races 3, 15, 32, 68, and three undescribed races. A culture of race 76 was heterozygous for both pathogenicity and urediospore color. Aeciospores of this race produced uredia of two different shades of yellow in addition to uredia of normal color. Aeciospores derived from teliospores collected in the field also gave rise to uredial strains of yellow spore color. Most of the yellow rust strains were decidedly low in pathogenic vigor.

Weed-host range of California aster yellows

Abstract does not appear. First page follows. Introduction (Kunkel (1926), (1931)4 recorded for the virus of New York aster yellows an extensive host range of 184 species of plants in 151 genera belonging to 38 families. He found 12 species of naturally infected weeds in 4 families, as follows: Compositae, composite family: Horseweed, Erigeron canadensis L. Erigeron speciosus (Lindl.) DC. Galinsoga, Galinsoga parviflora Cav. Helenium autumnale L. Helenium nudiflorum Nutt. Fall dandelion, Leontodon autumnalis L. Black-eyed Susan, Rudbeckia hirta L. Perennial sow thistle, Sonchus arvensis L. Common sow thistle, Sonchus oleraceus L. Plantaginaceae, plantago family: Common plantain, Plantago major L. Rosaceae, rose family: Rough cinquefoil, Potentilla moospeliensis L. Umbelliferae, parsley family: Wild carrot, Douous Oarota L. (Ogilvie (1927a), (1927b) reported aster yellows (strain not specified) to be common in the Bermuda Islands and observed that several wild plants were affected, the commonest being common sow thistle, Sonchus oleraceus. (Severin (1929), (1938) determined the following 2 species to be hosts of the California aster-yellows virus: Plantaginaeeae, plantago family: Common plantain, Plantago major L. Umbelliferae, parsley family: Poison hemlock, Conium maculatum L.

A Proliferation of the Sorghum Spikelets.

An interesting phenomenon of proliferation of a sorghum earhead was observed in the summer season of 1940 in a seed multiplication plot of an yellow grain sorghum strain (A. S. 809). While removing rogues at the flowering time, one earhead was observed to have rather longer spikelets, though in other respects, the plant was normal. The plant was as well developed and as tall as its neighbours, and the size and shape of the earhead also appeared normal. A closer examination of the earhead re vealed that the fertile spikelets had not opened. While the spikelets of the normal plants were awned, the awns being about one centimetre in length, there was a complete suppression of the awn in the proliferated earhead. It was also observed that the spikelets in the basal regions of the earhead were reduced to scale-like structures.

INFLUENCE OF HOST NUTRITION ON SYSTEMIC DEVELOPMENT OF TOBACCO MOSAIC

In two previous papers it was shown (3, 4) that the mineral nutrition of tobacco plants had a marked effect on their susceptibility to primary infection with a yellow strain of tobacco-mosaic virus. In the present paper the influence of host nutrition on systemic infection of this same virus in infected tobacco plants will be discussed. Several workers have studied the movement of virus in plants, but little attention has been given to the influence which host nutrition may have on systemic spread of virus. Boning (1), in 1928, published the results of an experiment dealing with the effect of nitrogen nutrition on mosaic-virus spread in tobacco. The tip of the largest leaf on each plant was inoculated. With actively growing plants an average of 3 days was required for the virus to pass 13 cm. from the tip of the leaf to the stem. With slow-growing, nitrogen-deficient plants an average of at least 6 days was necessary for the virus to pass from a leaf 12 cm. long. Boning concluded that the rapidity of virus-spread from an inoculated leaf was greatly decreased by nitrogen deficiency. Yolk (5) studied the effect of potassium, phosphorus, and nitrogen on the spread of streak in tomato plants grown in nutrient sand cultures, and inoculated just prior to fruiting. He concluded that the spread of streak disease was most rapid and the effect of the disease most severe in plants fertilized with an ample supply of potassium and phosphorus or in plants deficient in nitrogen.

FURTHER SEROLOGICAL STUDIES OF PLANT VIRUSES

Summary.Precipitin reactions with several plant viruses propagated in serologically unrelated hosts offer additional evidence that the virus is, in itself, antigenic.Reciprocal precipitin tests show that the viruses of cucumber mosaic, tobacco ringspot, and tobacco mosaic are serologically distinct; whereas tobacco mosaic virus, aucuba mosaic virus (green and yellow strains), and probably tomato streak virus remain serologically indistinguishable.No soluble specific substance was isolated from the juice of virus diseased plants or of healthy tomato by the methods employed.

Two Strains of Streak: A Virus Affecting the Tomato Plant

The symptoms produced by a green strain of tomato streak virus 1 upon a variety of Solanaceous plants are described. A yellow variant of the streak virus which appears to have arisen during the culturing of the green strain is also described. This variant produces local yellow spots upon all inoculated leaves of White Burley tobacco.Healthy tobacco plants have been infected with the green strain of the streak virus by spraying them with a virus suspension from an atomiser.The behaviour of the green and yellow virus strains when, co-existing in the tobacco plant is discussed.Filtration through graded collodion membranes shows that the two strains have different filtration end-points and that therefore they can be separated by this means. The difference in filterability is considered to be a quantitative effect and cannot yet be assigned to difference in particle size.Immunity tests have shown that a complete cross-immunity exists between the green and yellow strains of streak themselves, between them and two other strains of streak which produce local lesions and between the green and yellow strains and tobacco virus 1. No immunity was found between the streak viruses and those of tobacco necrosis, tobacco ringspot, tomato spotted wilt and potato virus X.The yellow strain of streak produced local yellow spots on mature leaves of White Burley tobacco. This suggests that the chlorophyll is actually attacked by the virus, and that the formation of the chlorotic spots is not due merely to the inhibition of plastid formation by the virus.

CAN A PYRROLE DERIVATIVE BE SUBSTITUTED FOR IRON IN THE GROWTH OF PLANTS?

In a preliminary note Pollacci and Oddo (4) discuss the presence of iron in the pigment of vertebrate blood and that of magnesium in the chlorophyll of green plants, and the fact that these metals are bound to organic complexes which yield similar pyrrole compounds on reduction. An experiment was described in which corn seedlings were grown in a nutrient solution lacking iron and in one containing a magnesium salt of pyrrole carbonic acid in place of iron. After 20 days' growth the corn plants in the solution containing the pyrrole salt were normally green and three times the size of the chlorotic plants grown without iron. In a more extensive paper (3) these investigators report normal growth and chlorophyll-development of 6 species of plants in solutions containing this pyrrole salt but lacking iron. From these experiments and from the analytical work of Willstatter (5, 6) upon the chemistry of chlorophyll the theory was advanced that iron functions as a catalyst in the formation of pyrrole groupings which go to make up the nucleus of the complex chlorophyll molecule. The Italian workers contend that, when the pyrrole group is supplied to plants in a form which can be used, iron becomes unnecessary for the formation of chlorophyll. The writer became interested in this subject through efforts to induce chlorophyll-development in some genetically yellow corn strains. It was soon apparent that considerable work would have to be done to secure positive results with normally green plants with a pyrrole salt substituted for iron. The main object of the present investigation therefore became an attempt to confirm the work of Pollacci and Oddo. The literature dealing with the physiological action of pyrrole compounds in relation to plants is very limited. Ciamician and Galizzi (i) report that pyrrole carboxylic acid and dimethyl-pyrrole dicarboxylic acid are not toxic to plants. R. Emerson of Harvard University, in a communication to the writer, states that 2-4-dimethyl-3-5-dicarbothoxy-pyrrole and 2phenoxy-pyrrole have been used in nutrient solutions for the growth of several species of plants with varying success. The magnesium salt of pyrrole carbonic acid used in these experiments, except for a small sample received from Prof. Oddo, was prepared by J. S. Chu 1 and the writer in the Organic Chemistry Laboratory of the