The rhizosphere microflora of wheat grown under controlled conditions I. The effect of soil fertility and urea leaf treatment on the rhizoplane microflora

Summary Microbial colonization of seminal roots of seedlings and of nodal roots of tillering plants was studied on spring wheat ‘Kaspar’ cultivated in growth, chambers. Methods were developed to microbially condition the soil before seeding and to regulate soil humidity. Addition of inorganic nutrients (NPK) to the soil increased the number of rhizoplane bacteria and actinomycetes, but did not effect the number of fungi on seminal and nodal roots. Urea leaf treatments stimulated bacteria and actinomycetes 7 and 9 days after treatment. Fourteen days after urea leaf treatment, however, bacterial numbers were mostly reduced, especially on seminal roots, while numbers of actinomycetes generally equalled the control. Root types and soil fertility did not obviously interact with the effect of urea leaf treatment on rhizoplane bacteria and actinomycetes. The only effect of urea on total numbers of fungi, was a reduction of their numbers on seminal roots 9 days after treatment at both NPK-levels.     

Fungitoxic and phytotoxic effects of fungicides controlling powdery mildew on apple

Benomyl, pyrazophos (HOE 2873), triarimol, triforine and the non-systemic fungicide diethyl phthalimidophosphonothionate (Dowco 199) were sprayed at c. 200 gal/acre (2250 1/ha) at 14-day intervals from pink bud (late April/early May) on seven apple cultivars including Cox's Orange Pippin, Golden Delicious and Jonathan. Compared with binapacryl or dino-cap (and with elemental sulphur on the sulphur-tolerant cv. Golden Delicious), these compounds were more phytotoxic without substantially or consistently improving the control of Podosphaera leucotricha; fruit russet was increased and the crop and fruit size of some cultivars were reduced in some trials. In 1969 the inclusion of bis(dimethylthiocarbamoylthio)-methylarsine (44 ppm) as Urbacid^(R) in the sprays reduced russeting by benomyl and Dowco 199 so that these fungicides became as safe as captan on several cultivars; Dowco 199 was also safened by captan (500 ppm). Urbacid^(R) (88 ppm a.i.) safened benomyl and triarimol on fewer cultivars in 1970 when russet was less severe. The addition of Urbacid^(R) did not prevent yield losses caused by sprays in either year. The crop is most sensitive to spray damage from pink bud until late June. This is a crucial period for the control of mildew, and unless new fungicides are less phytotoxic, palliatives may become necessary adjuvants.     

The effect of carbamide and thiocarbamide on the resistance of apple to apple scab

Carbamide and thiocarbamide decreased the resistance of apple to apple scab when infiltrated into apple leaves prior to infection with the disease. In three apple varieties these two substances strikingly stimulated infection with two monosporic isolates of the fungusVenturia inaequalis (Cke.) Wint. It was established that both carbamide and thiocarbamide inhibited polyphenol oxidase activity in apple leavesin vivo, butin vitro only thiocarbamide was inhibitory. It can be concluded that the effect on apple resistance to apple scab is based on an inhibition of polyphenol oxidase.     

Factors that effect leaf regeneration efficiency in apple,and effect of antibiotics in morphogenesis

Several factors that affect the frequency of organogenesis in apple leaf explants were examined for the scion cultivars Empire, Freedom, Golden Delicious, Liberty, McIntosh, and Mutsu and for the rootstocks Malling 7A and Malling 26. The main factors affecting morphogenesis were BA concentration, basal medium, leaf explant origin and maturity, explant orientation, and photosynthetic photon flux. Depending on the genotype, optimal regeneration was obtained using either 22.2 or 31.1 M BA and the N6 basal medium, with the exception of Golden Delicious which regenerated better on MS medium. After 6 weeks, the average number of shoots per segment varied from 5 to 16, and the percentage of regeneration between 70 and 100%, depending on the genotype tested and the maturity of the explant. Regeneration capacity increased dramatically from the tip towards the base of the leaf, and was higher from the middle to the proximal end.Cefotaxime and carbenicillin, two antibiotics commonly used during transformation studies to eliminate Agrobacterium tumefaciens from plant tissue, were tested to determine their effect on morphogenesis. Cefotaxime at a dose of 250 mg 1^-1 enhanced regeneration and shoot development, whereas carbenicillin at a dose of 500 mg l^-1 induced abundant callus formation and inhibited regeneration. Kanamycin, a widely used selection agent for plant transformation, strongly inhibited regeneration even at very low doses. Schemes for selection and recovery of transgenic apple plants when kanamycin is used as the selection agent are discussed.Abbreviations BA benzyladenine - Cef cefotaxime - Crb carbenicillin - IBA indolebutyric acid - Kan kanamycin - LS Linsmaier and Skoog (1965) medium - M Malling - MS Murashige and Skoog (1962) medium - NAA naphthaleneacetic acid - N6 medium (Chu et al. 1975) as modified by Welander (1988) - PPF photosynthetic photon flux     

Population biology of Aureobasidium pullulans on apple leaf surfaces

Colonization of apple leaves by the yeast-like fungus Aureobasidium pullulans was studied in the field on eight dates over 2 years. Population densities from adaxial leaf surfaces were approximately log10 0.5-2.6 U higher when enumerated directly along line transects as microscopic counts of A. pullulans cells specifically identified by fluorescence in situ hybridization (FISH) than indirectly as CFU obtained by plating leaf washings from comparable surfaces onto nutrient media. Site-specific mapping of the leaf landscape colonized by A. pullulans was facilitated by use of geographic information system (GIS) software. Colonization was plotted and analyzed both qualitatively (as occupancy) and quantitatively (as density). Overall, when expressed as mean occupancy per date, 22-42% of the microscope fields (each 0.196 mm2) contained > or = 1 A. pullulans cell. Occupancy on a microscope field basis was greater over the midvein (47-89%) or smaller veins (49-65%) than over interveinal regions (11-21%). Intensity of colonization, whether expressed as percentage of total A. pullulans cells associated with a particular leaf feature or as cell density per unit area, was also significantly greater (P < 0.05) over the veinal areas compared with the interveinal areas. The primary fungal morphotypes involved in colonization were blastospores, swollen cells, and chlamydospores; only infrequently were hyphae or pseudohyphae seen. Numbers of microcolonies (> or = 10 clustered cells) and percentage of total A. pullulans cells that occurred as microcolonies increased over the growing season and were significantly greater (P < 0.05) over veinal regions compared with interveinal regions. Locally high concentrations of A. pullulans were associated with naturally occurring micro-wounds in interveinal areas. We conclude that A. pullulans colonizes the phylloplane predominantly as single cells and groups thereof in a highly heterogeneous fashion and that sites exist that are relatively conducive (veins; wounds) or nonconducive (unwounded interveinal areas) for epiphytic fungal growth.     

The effect of enterococci on normalizing the intestinal microflora in experimental dysbacteriosis

The normal microflora of the intestine produces essential influence on the vital activity of the host. The exposure of the body to the action of different unfavorable factors (roentgen radiation, the administration of antibiotics, Salmonella infection, etc) results in changes in the normal microflora of the gastrointestinal tract. This work was aimed at the study of the influence of Streptococcus faecium YDC-48 on the intestinal microflora of mice in experimental (chemotherapeutic, postirradiation) dysbacteriosis and Salmonella infection. The effect of the oral administration of S. faecium YDC-48 on the correction of the intestinal microflora of mice in cases of dysbacteriosis etiology was studied. The intragastric administration of S. faecium YDC-48 was found to induce an increase in the level of lactobacterin and a decrease in the number of opportunistic microorganisms in chemotherapeutic and postirradiation dysbacteriosis. The oral administration of S. faecium YDC-48 decreased the manifestations of intestinal dysbacteriosis in experimental Salmonella infection. The possibility of developing a preparation on the basis of S. faecium YDC-48, a representative of normal intestinal microflora, is discussed.     

小檗碱对肠易激综合征大鼠肠道菌群的影响

目的 通过口服小檗碱（Berberine,BBR）治疗大鼠肠易激综合征（IBS）,初步研究小檗碱对IBS大鼠肠道菌群的影响。方法 用避水应激试验制作大鼠IBS模型,分别给予模型大鼠小剂量（25 mg/kg）小檗碱、大剂量（100 mg/kg）小檗碱和利福昔明干预治疗10 d,检测大鼠肠道菌群丰度、生物多样性及菌群结构组成的变化。结果 避水应激试验造模后模型组大鼠排便次数增多、腹外斜肌EMG明显升高,肠道可见微炎症表现。小檗碱干预后,IBS大鼠排便增多情况、内脏高敏感性和肠道微炎症情况均显著改善,其中大剂量小檗碱组优于小剂量组。经小檗碱干预后,大鼠肠道菌群多样性显著降低,大剂量小檗碱抑菌作用强于小剂量小檗碱。大剂量小檗碱可显著提高IBS大鼠肠道乳杆菌科细菌的比例,同时降低肠杆菌科细菌的比例。结论 小檗碱可以显著降低IBS大鼠内脏高敏感性,改善肠道微炎症,减少IBS大鼠排便增多症状。小檗碱可以调节肠道菌群丰度和多样性,且剂量越大,抑菌作用越明显。肠道乳杆菌科细菌在小檗碱治疗肠易激综合征的过程中可能起一定作用。     

The effects of a pesticide program on microbial populations from apple leaf litter

The leaf litter microbial community was quantitatively and qualitatively changed when a standard pesticide schedule that comprised an insecticide, a bactericide, and a fungicide was applied to McIntosh apple trees in the summer. Effects were observed for two winters by four indirect assays and three direct methods. Populations were altered qualitatively both years, but the most striking difference was the quantitative impact from year to year. Bacteria, filamentous fungi, and yeasts from treated leaves were reduced 10- to 10 000-fold between November 1976 and April 1977 and did not recover until snow cover had melted in March. Reductions in 1977-1978 were negligible. The marked seasonal difference is attributed to meteorological influences. Fluorescent pseudomonads were among the bacteria depressed by chemicals. Of the 49 genera of fungi and yeasts isolated, Coniothyrium sp., Penicillium spp., Arthrobotrys spp., and Nodulisporium sp. were appreciably reduced, whereas Typhula spp., Pleurophomella sp., Sporobolomyces spp., and Rhodotorula spp. were substantially enhanced by the spray program.     

Plant regeneration from leaf protoplasts of apple

Protoplasts were isolated from young leaves or etiolated shoot apices. For initiation of divisions the protoplasts were embedded in sodium alginate and cultivated in MS or MI medium supplemented with 2.2 M BA, 2.6 M NAA and 2.2 M 2,4-dichlorophenoxyacetic acid. The protoplasts of all seven lines tested developed to protocalluses at high frequencies. No genotypic differences were observed. When BA was used in combination with NAA in the regeneration experiments, only a few protocalluses (highest frequency 3%) exhibited shoot organogenesis. When BA was replaced with thidiazuron, the percentage of protocalluses that developed shoots increased in two of three tested lines to 7% and 56%, respectively. Shoot development was achieved under light conditions. The shoots were then rooted and transferred into soil.Abbreviations ABA abscisic acid - BA 6-benzyladenine - 2,4-d 2,4-dichlorophenoxyacetic acid - FW fresh weight - GA₃ gibberellic acid - IBA indole-3-butyric acid - MES 2-N-morpholinoethane sulphonic acid - NAA -naphthaleneacetic acid     

The effect of soil microflora on the survival of cuttings of Epacris impressa

A study was conducted to test the effect of inoculation with soil containing mycorrhizae propagules and other soil micro organisms on survival of stem cuttings of Epacris impressa. With non-sterile soil present, the cuttings were mycorrhizal, more survived and the survivors were healthier, with more flowers and roots, although root area was not increased. Soil inoculum thus increased the success of propagation of Epacris impressa for conservation purposes and in commercial horticulture.     

The effect of fermented-milk bifidumbacterin on the intestinal microflora of test pilots]

Bacteriological study of intestinal microflora in test pilots, regularly exposed to excessive physical, as well as nervous and emotional strain, has revealed changes in the composition of their intestinal microflora. Correction of microflora by means of bifidumbacterin, a curative lactic fermentation alimentary product, was carried out. Rapid and effective restoration of intestinal microflora and improvement of the general state of patients were noted, which made it possible to recommend this product as a prophylactic remedy for subjects at risk of development of dysbiotic disturbances.     

The effect of atmospheric SO2 pollution on the microflora of forest soils

The existing knowledge of the effects of industrial SO₂ immissions on forest soil microflora is reviewed. Most Czechoslovak data were obtained in heavily polluted spruce stands in the Ore Mountain and in the Slavkov Forest (NW Bohemia). The industrial SO₂ immissions soil. Pseudomonads yield to yellow-and red-pigmented microorganisms, among micromycetes there is a higher incidence of the generaRhizopus andMucor. The biochemical capabilities of the bacterial populations are reviewed: the immissions have a negative effect on the occurrence and efficiency of heterotrophic nitrifiers, increase the concentration of autotrophic as well as heterotrophic oxidizers of S⁰ and of sulfite-resistant bacteria. The soil activities of the C and N cycles are inhibited whereas the oxidation of S⁰ is stimulated. Changes in the soil of spruce stands are probably due to intoxication with sulfur dioxide (and possibly with sulfite) rather than to acidification. Replacement of withered spruce stands with mountain ash brings about a dramatic improvement of the soil microflora. Presented at the16th Congress of the Czechoslovak Microbiological Society, Banská Bystrica, October 21–23, 1983.