Effect of polyphenols on shoot and root growth and on seed germination

The effect of high concentrations of the simplest polyphenols on extension growth of maize (Zea mays L.) shoot ooleoptile segments, lettuce (Lactuca sativa L.) roots, and on radish (Raphanus sativus L.) seed germination, was studied. Quinone formation in the process of plant incubation in polyphenol solutions was proved. The data obtained are presumably explained by the important part that is played by the quinoid products of phenol oxidation in the ability ofo- andp-biatomic phenols to inhibit growth.     

Tree regeneration on rotten wood and on soil in old-growth stand

Forest regeneration on soil and on decaying wood was studied in natural mixed stand of Facus sylvatica L., Abies alba Mill. and Picea abies Karst. in Babia Góra National Park, Western Carpathians.Downed wood, divided into five decay classes covered around 6% of the forest floor. Among seedlings, Fagus and Abies codominated, while Picea was less numerous. The average seedling density on the soil with herb layer (240 ind./100 m²) was higher than on the logs, even on the strongly decayed ones (177 ind./100 m²). However, the density of Abies and Picea seedlings was higher on the rotten wood than on soil. Seedling survival of all species was better on the logs, especially in conifers. Because of the total dominance of Fagus among saplings, the presence of Abies and Picea in the next generation of canopy trees can strongly depend upon their regeneration on decaying wood.     

Studies on peat and peat microorganisms

Summary The isolation of thermophilic fungi from peat is reported and their taxonomy is discussed. Mucor pusillus was frequently found in peat. Humicola was recorded for the first time as occurring in peat. The thermophilic strains were classified as H. insolens, H. stellatus, and H. lanuginosus respectively. Paecilomyces commonly occur in peat. Up to now only thermotolerant Pacecilomyces were reported. Our thermophilic strains resemble Paecilomyces in appearance, but after detailed examination may belong to the related genera Talaromyces or also Thermoascus.Because of its wide temperature range Aspergillus fumigatus was very frequently isolated under thermophilic conditions.Part I.: see Küster, E., and R. Locci: Arch. Mikrobiol. 45, 188–197 (1963).     

Effect of Anabaena flos-aquae on the abilities of Daphnia and Keratella to feed and reproduce on unicellular algae

SUMMARY.

• 1 This study tests the hypothesis that the filamentous cyanobacterium, Anabaena flos-aquae, inhibits Daphnia's ability to feed and reproduce on unicellular algae more than it does Keratella's. Double-label radiotracer experiments using whole and sonieally disrupted Anabaena filaments showed that even low concentrations of Anabaena (5 × 10³ cells ml^?1) inhibited the abilities of Daphnia pulex and D. galeata mendotae to feed on Chlamydomonas and that this inhibition was due to both mechanical interference with feeding and increased food availability. A single-label radiotracer experiment showed that Anabaena (5 × 10³ and 2 × 10⁴ cells ml^?l) reduced the abilities of neonate, juvenile, and adult D. pulex to feed on Chlamydomonas but had a much more pronounced effect on adults.
• 2 Single-label radiotracer experiments using screened (25 μm mesh) and unscreened suspensions of whole Anabaena filaments showed that only very high concentrations of Anabaena (10⁵ cells ml^?1) reduced the ability of Keratella cochlearis to feed on Cryptomonas and that this inhibition probably was due to mechanical interference with feeding, since Keratella ate Anabaena extremely inefficiently - especially when single cells and short filaments were removed by screening.
• 3 Experiments comparing the survivorship and fecundity of individuals fed Anabaena, Chlamydomonas, or no food showed that the Anabaena was not toxic to either Keratella or D. galeata mendotae, was not utilized by Keratella, and was utilized by Daphnia, although not as well as Chlamydomonas was.
• 4 Anabaena (5 × 10³ or 10⁴ cells ml^?1) did not affect, or slightly increased, the population growth rate (r_m) of K. cochlearis on Cryptomonas, while it substantially increased that of D. pulex, Duphnia's ability to utilize Anabaena probably more than offset its reduced ability to feed on Cryptomonas. The presence of cyanobacterial filaments in natural plankton communities could adversely affect Daphnia and decrease its ability to competitively suppress Keratella and other rotifers if the filaments were of little nutritional value to the Daphnia, greatly interfered

     

Effects of increased and deregulated expression of cell division genes on the morphology and on antibiotic production of streptomycetes

This paper describes the effects of increased expression of the cell division genes ftsZ, ftsQ, and ssgA on the development of both solid- and liquid-grown mycelium of Streptomyces coelicolor and Streptomyces lividans. Over-expression of ftsZ in S. coelicolor M145 inhibited aerial mycelium formation and blocked sporulation. Such deficient sporulation was also observed for the ftsZ mutant. Over-expression of ftsZ also inhibited morphological differentiation in S. lividans 1326, although aerial mycelium formation was less reduced. Furthermore, antibiotic production was increased in both strains, and in particular the otherwise dormant actinorhodin biosynthesis cluster of S. lividans was activated in liquid- and solid-grown cultures. No significant alterations were observed when the gene dosage of ftsQ was increased. Analysis by transmission electron microscopy of an S. coelicolor strain over-expressing ssgA showed that septum formation had strongly increased in comparison to wild-type S. coelicolor, showing that SsgA clearly influences Streptomyces cell division. The morphology of the hyphae was affected such that irregular septa were produced with a significantly wider diameter, thereby forming spore-like compartments. This suggests that ssgA can induce a process similar to submerged sporulation in Streptomyces strains that otherwise fail to do so. A working model is proposed for the regulation of septum formation and of submerged sporulation.     

Biochemical Studies on Polyamine and Its Analogues

The phagocidal action of oxidation products of natural and synthetic amines by crystalline amine oxidase preparations has been investigated with a large variety of bacteriophages. Oxidized spermine was shown to inactivate T3, T5, T7, MS2, ?80, λ (Escherichia coli); ε¹⁵, ε³⁴ (Salmonella anatum); Al (Bacillus subtilis); P465, P468, Ap85, P4 (Brevibacterium lactofermentum); I128T (Pseudomonas glycinea), I2418 (Xanthomonas phaseoli) and PK66 (Streptomyces griseus). Phages of T2, T4, T6, ?X174 (E. coli), P22 (S. anatum) and M2, SP10 (B. subtilis) was not inactivated. Essentially the similar activity was observed with the oxidation products of spermidine and synthetic polyamines analogous to spermine.

The reduction of logarithmic titers of survival phages by the oxidized polyamines proceeded linearly with both incubation time and concentration of the oxidized polyamines. Then, it is conceivable that the inactivation of phages may be due to the interaction between oxidized polyamine and phagal nucleic acid.     

Notes on the Laboulbeniales (Ascomycota) parasitic on Diptera from Portugal and other countries

Eighteen species of Stigmatomyces are reported for the first time from continental Portugal and/or from the Azores. These are Stigmatomyces asteiae W. Rossi et Cesari, Stigmatomyces athyroglossae W. Rossi et Cesari, Stigmatomycescanzonerii W. Rossi et Cesari, Stigmatomyces ceratophorus Whisler, Stigmatomyces constrictus Thaxt., Stigmatomyces crassicollis Thaxt., Stigmatomyces divergatus Thaxt., Stigmatomyces discocerinae Thaxt., Stigmatomyces ensinae Thaxt., Stigmatomyces cf. ephydrae L. Mercier et R. A. Poiss., Stigmatomycesgeomyzae W. Rossi et Cesari, Stigmatomyces limnophorae Thaxt., Stigmatomyces majewskii H. L. Dainat, Manier et Balazuc, Stigmatomyces papuanus Thaxt., Stigmatomycesplatensis Speg., Stigmatomyces ptylomyiae Thaxt. and Stigmatomyces purpureus Thaxt., Stigmatomyces rugosus Thaxt. New records of these species are also reported from Australia, Canada, Canary Islands (Spain), Costa Rica, Cuba, Ecuador, Finland, Germany, Great Britain, Greece, Kenya, Hungary, Israel, Kyrgyzstan, Lebanon, Morocco, Saudi Arabia, Sierra Leone, Taiwan, Thailand, Turkey, Uganda, United Arab Emirates, USA, Yemen and Zimbabwe. The new records increase, sometimes considerably, information about distribution of these parasites. Two synonymies are also established: Stigmatomyces autriquei Balazuc = Stigmatomyces ensinae Thaxt.; Stigmatomyces psilopae Thaxt. var. camarguensis H. L. Dainat et J. Dainat = S. rugosus Thaxt.     

Effects of mummy consumption on fitness and oviposition site selection on Harmonia axyridis

Intraguild predation (IGP) has been commonly reported between predators and parasitoids used as biological control agents as predators consuming parasitoids within their hosts. However, the effect of parasitoid–mummy consumption on the fitness of the predator and subsequent oviposition site selection have not been well studied. In our study, we conducted two laboratory experiments to examine the influence of Aphidius gifuensis Ashmead (Hymenoptera: Braconidae) mummies as prey on fitness and subsequently oviposition site selection of Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae). Results indicate that when H. axyridis was reared on A. gifuensis mummies only, its larval development was prolonged, and body weight of the 4th instar larvae and newly emerged adults, and fecundity decreased. Moreover, H. axyridis did not exhibit oviposition preference on plants infested with unparasitized aphids or aphids parasitized for shorter than 9 days. However, compared with plants with mummies (parasitized ≥9 days), H. axyridis laid more eggs on plants with unparasitized aphids. In contrast, H. axyridis previously fed with A. gifuensis mummies did not show a significant oviposition preference between plants with unparasitized aphids and those with mummies (parasitized ≥9 days). Overall, our results suggest that mummy consumption reduced the fitness of H. axyridis. Although H. axyridis avoided laying eggs on plants with A. gifuensis mummies, prior feeding experience on A. gifuensis mummies could alter the oviposition site preference. Thus, in biological control practice, prior feeding experience of H. axyridis should be carefully considered for reduction of IGP and increase of fitness of H. axyridis on A. gifuensis.     

Studies on five species of Pythium parasitic on mustard and cabbage in India

Diseased seedlings and roots of cabbage and mustard of Khurpatal (Nainital), were surveyed for zoosporic plant pathogens. Pythium aphanidermatum and P. debaryanum were isolated from cabbage and P. middletonii, P. spinosum and P. undulatum were isolated from mustard. Pathogenicity tests conducted in the glasshouse indicated that P. debaryanum and P. spinosum are the most virulent pathogens of cabbage and mustard respectively.     

Temperature and incubation time effects on growth and ochratoxin A production by Aspergillus sclerotioniger and Aspergillus lacticoffeatus on culture media

Aims: As there is no knowledge of the influence of abiotic factors on the two new ochratoxin A (OTA)‐producing species Aspergillus sclerotioniger and Aspergillus lacticoffeatus, the aim of this study was to evaluate the effect of temperature and incubation time on growth and OTA production by these species on culture media. Methods and Results: The study was carried out on yeast extract sucrose agar (YES) and Czapek yeast extract agar (CYA) incubated at ten different temperatures from 5 to 50°C (at 5°C intervals). Growth assessment and OTA production were determined after 5, 10, 15, 20 and 30 days of incubation at each temperature. Aspergillus sclerotioniger grew from 10 to 35°C; OTA was detected from 10 to 35°C and the highest concentration was achieved at 15°C in CYA. Aspergillus lacticoffeatus grew from 10 to 45°C; OTA was detected from 15 to 45°C, and the maximum concentration was produced after 5 days at 25°C in YES. Conclusions: The studied species can produce OTA over a wide range of temperatures and significant amounts can be produced in only 5 days. Significance and Impact of the Study: This is the first report on the influence of ecophysiological factors on these two ochratoxigenic species. The pattern of effects of temperature on growth and OTA production by A. sclerotioniger and A. lacticoffeatus was similar to those reported for the closely related species Aspergillus carbonarius and Aspergillus niger, respectively. The two new OTA‐producing species have both been isolated from coffee beans, and the closely related ochratoxigenic species of section Nigri, A. carbonarius and A. niger are important sources of OTA in this substrate.     

Studies on peat and peat microorganisms

Summary Thermophilic Actinomycetes were isolated from various peat samples and examined in detail. Most of them were classified as Thermoactinomyces vulgaris, a species which frequently occurs in very different habitats.The characters which separate Thermoactinomyces thalpophilus from Thermoactinomyces vulgaris are discussed. They are unstable and not sufficiently characteristic so that the taxonomic position of Thermoact. thalpophilus now becomes doubtful. Thermomonospora viridis comb. nov. which is distinguished by a graygreen aerial mycelium and the formation of a green pigment has been particularly studied and described. Thermoactinomyces monosporus Schütze and Thermoactinomyces viridis Schuurmans are synonyma. Streptomyces strins isolated and grown at 45° C should be called thermotolerant rather than thermophilic. They differ from known nesophilic species in their temperature requirements only.     

Identification of catalase-producingCampylobacter species based on biochemical characteristics and on cellular fatty acid composition

A total of 50 catalase-positive campylobacters from human and animal sources were studied. The nomenclatural type strains ofCampylobacter coli, C. jejuni, C. fetus, andC. fetus subsp.venerealis, a typical strain of the nalidixic acid-resistant thermophilic group, and various clinical isolates were characterized by bacteriological tests and by gas-liquid chromatographic analysis of their cellular fatty acids. The tests most useful in the differentiation of the various catalase-positive species were growth at 25 and 42°C, H₂S production, tolerance to nalidixic acid and to 2,3,5-triphenyltetrazolium chloride, and hippurate hydrolysis. The latter test was the only reliable means to differentiate betweenC. coli andC. jejuni. Differences between.C. fetus andC. jejuni/coli were confirmed by cellular fatty acid compositions. The bacteriological results indicated thatC. fetus andC. jejuni were distinct species, although within the thermophilic campylobacters there were several related taxa that included bothC. coli andC. jejuni strains with typicalC. coli and some thermophilic strains ofC. fetus subsp.fetus at the extremes.     

Taxonomic studies on Filobasidiella species and their anamorphs

The taxonomy of Filobasidiella neoformans Kwon-Chung and F. bacillispora Kwon-Chung and their anamorphs were reinvestigated. Although the cross between the type cultures of the two species failed to produce viable basidio-spores, another pair of isolates did yield viable basidiospores. The segregation of phenotypic markers among the tetrads isolated from this interspecific cross proved that meiosis had occurred. On the basis of other previously known differences and the present genetic study, the two species are now considered to be two varieties of the species, F. neoformans. The anamorph of F. neoformans var. neoformans grew well at 37°C in vitro and produced fatal infection in mice while that of F. neoformans var. bacillispora grew poorly at 37°C and failed to produce fatal infection in mice. Cryptococcus bacillisporus Kwon-Chung et Bennett is regarded as a synonym of C. neoformans var. gattii Vanbreuseghem et Takashio.     

冬季郑州市12个常绿树种的光合特性及滞尘能力

为筛选出北方城市冬季生态效益突出的常绿树种,以缓解大气CO2和粉尘颗粒物污染,并为这些树种的园林应用提供科学支持,该文选取郑州市园林绿化应用广泛的12个常绿树种,利用LI-6400便携式光合测定仪和洗脱-质量差值法,并对其光合特性及滞尘能力进行测定,计算出其光合参数[叶片的净光合速率(Pn)、蒸腾速率(Tr)、气孔导度...     

Iron plaque formation on wetland plants and its influence on phosphorus,calcium and metal uptake

We investigated Fe plaque formation and Ca, Cu, Mn, Zn, and P uptake capacities of fifteen kinds of wetland plants. The test plants were cultured in 3 l nutrient solutions for 8 days. Fe plaque was induced by adding 200 mg l⁻¹ Fe²⁺ as FeSO₄·7H₂O for 4 days in one set of experiment and 8 days in another. This plaque ranged from 2.38 to 8.67 mg g⁻¹ of plant root after 4 days and from 4.56 to 15.71 mg g⁻¹ of plant root after 8-day treatment. In both experimental durations, the plaque was significantly correlated with root surface area (r = 0.904 and 0.878, P < 0.01). Thus, Canna generalis, Typha latifolia and Thalia dealbata, with their larger root surface areas (>1,400 cm²), formed relatively greater Fe plaque amounts. The amounts of Ca, Cu, Zn and P in the Fe plaques were significantly correlated with Fe plaque amount, (r = 0.819, 0.742, 0.693, 0.917, respectively, for these four elements for the 4-day treatment; and r = 0.917, 0.768, 0.949, 0.872, respectively, for 8-day treatment, P < 0.01). Plants varied widely in accumulating Ca, Cu, Mn, Zn, and P in their tissues. The amounts accumulated on root were significantly correlated with Fe plaque amount in both for 4- and 8-day exposure treatments with Fe (r = 0.973, 0.847, 0.709, 0.837, 0.892, respectively, for 4-day treatment; and r = 0.943, 0.691, 0.843, 0.957, 0.983, respectively, for 8-day treatment, P < 0.01). No such significant correlations were found for the Fe plaque in shoot. Canna generalis, Typha latifolia and Thalia dealbata were superior in Ca, P and Zn uptake, while Canna generalis and Thalia dealbata accumulated Cu and Mn well in case of concentrated wastewater treatment.     

Effects of plant trichomes on herbivores and predators on soybeans

Abstract Tritrophic interaction in soybean system has received increasing attention recently. However, few studies have investigated the influence of plant trichomes on the population dynamics of soybean herbivores and their natural enemies. We conducted a field survey to investigate whether soybean trichomes affected the abundance of herbivores and their predators. The results of this study show that moderately or densely pubescent trichomes have positive influences on the abundance of some herbivores (e.g., Stollia guttiger) and predators (e.g., Propylaea japonica and Orius similes) although the influence may change over time, while trichome types do not affect the density of soybean aphid, Aphis glycines.     

Differential Impacts of Copepods and Cladocerans on Lake Seston,and Resulting Effects on Zooplankton Growth

In an enclosure study in Schöhsee, a small mesotrophic lake in Northern Germany, the impact of copepods and daphniids on the seston community was studied. In general, these two guilds differ in their feeding behaviour. Copepods actively select their food, with a preference for larger particles, whereas most cladocerans are unselective filter-feeders. In this study we investigate how the impact of the two different grazers affects zooplankton growth. We combine results obtained in the laboratory with results measured in situ in the enclosures. Copepods and cladocerans were cultured on seston from enclosures that were inhabited by density gradients of copepods or daphniids. We observed that Daphnia grew faster on seston that was pre-handled by copepods than on seston that was pre-handled by daphniids, and that somatic growth decreased with increasing densities of daphniids in the enclosures. In contrast, we observed no differences in development rates for copepods grown on the different media. The population growth rates of Daphnia in the Daphnia treatments were determined in the enclosures. Growth differences in both somatic- and population growth of Daphnia were correlated to food quality aspects of the seston. In the laboratory we found that Daphnia growth was correlated with several fatty acids. The strongest regression was with the concentration of 20:43 (r ²= 0.37). This particular fatty acid also showed the highest correlation with growth after normalisation of the fatty acids to the carbon content of the enclosures (r ²= 0.33). On the other hand, in the enclosure the population growth correlated most to the particulate nitrogen content (r ²= 0.78) and only to the N:C ratio, when normalised to carbon (r ²= 0.51).     

Effects of nutrients and warming on Planktothrix dynamics and diversity: a palaeolimnological view based on sedimentary DNA and RNA

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Effect of anoxia on the kinetic properties of pyruvate kinase and phosphofructokinase,and on glycogen phosphorylase activity in marine worms and earth worms

Summary The kinetic properties of PK and PFK were studied in aerobic versus 12-hours anoxic marine worms Hedistae(=Nereis) diversicolor and Diopatra neapolitana and earth worms Allolobophora calliginosa and Eisenia foetida. The total glycogen phosphorylase (a+b) activity and the percentage of active a form were also measured in the marine and earth worms under the same conditions. Anoxia exposure did not result in any significant changes of kinetic parameters of PK and total activities of glycogen phosphorylase from marine worms, but it altered the kinetic characteristics of PFK from H. diversicolor. Chromatographical studies showed that PK from both aerobic and anoxic marine worms is eluted from DEAE-cellulose as a single peak at 50 mM KCl. In contrast to marine worms, however, anoxia caused a marked change in kinetic properties of PK from both earth worms, resulting in a reduction of enzyme affinity for its substrate PEP. In addition, the enzyme existed in both earth worms in two distinct variants eluted from DEAE-cellulose column as peak I and peak II at 50 mM and 150 mM KCl, respectively. The ratio of enzyme units (peak I/peak II) was reduced significantly after 12 h of anoxia, indicating that these two peaks are interconvertible. Anoxia also caused a reduction of total glycogen phosphorylase activity in E. foetida and lowered the percentage of active a form of the enzyme by approximately 50% in both earth worms. Kinetic properties of PFK from both earth worms were not significantly affected by anoxia. However, their low Ka values for F-2,6-P₂ imply that this effector may play an important role in PFK control in earth worms under anoxia.Abbreviations F6P fructose-6-phosphate - FBP fructose-1,6-bisphosphate - F-2,6-P fructose-2,6-bisphosphate - PEP phosphoenoylpruvate - PFK 6-phosphofructo-1-kinase (E.C.2.7.1.11) - PK pyruvate kinase (E.C.2.7.1.40) - Pi inorganic phosphate - PMSF phenyl methylsulfonyl fluoride     

Effects of salinity on growth and on valve morphology of five estuarine diatoms

The effects of salinity on the growth and valve morphology of five benthic estuarine diatoms (Nitzschia pusilla, N. frustulum, N. palea, N. filiformis var. conferta and Eolimna subminuscula), isolated from both freshwater and brackish/marine habitats, were investigated. The four Nitzschia strains grew well over a broad salinity range, though some (N. pusilla, N. frustulum) showed a broader salinity range tolerance (from fully saline down to at least 9.5 ppt) than others (N. palea, N. filiformis var. conferta had reduced growth at salinities of 16 ppt and above). Salinity significantly affected the valve morphology of the five strains studied. However, there was no consistent pattern in either the morphological characters affected or the direction of the effects. Although significant, the effects of salinity on valve morphology were very small and therefore it seems that the taxonomic usefulness of some of the classical taxonomical characters is not undermined.