Influence of Tomato Genotype on Growth of Inoculated and Indigenous Bacteria in the Spermosphere

We previously demonstrated a genetic basis in tomato for support of the growth of a biological control agent, Bacillus cereus UW85, in the spermosphere after seed inoculation (K. P. Smith, J. Handelsman, and R. M. Goodman, Proc. Natl. Acad. Sci. USA 96:4786–4790, 1999). Here we report results of studies examining the host effect on the support of growth of Bacillus and Pseudomonas strains, both inoculated on seeds and recruited from soil, using selected inbred tomato lines from the recombinant inbred line (RIL) population used in our previous study. Two tomato lines, one previously found to support high and the other low growth of B. cereus UW85 in the spermosphere, had similar effects on growth of each of a diverse, worldwide collection of 24 B. cereus strains that were inoculated on seeds and planted in sterilized vermiculite. In contrast, among RILs that differed for support of B. cereus UW85 growth in the spermosphere, we found no difference for support of growth of the biocontrol strains Pseudomonas fluorescens 2-79 or Pseudomonas aureofaciens AB254. Thus, while the host effect on growth extended to all strains of B. cereus examined, it was not exerted on other bacterial species tested. When seeds were inoculated with a marked mutant of B. cereus UW85 and planted in soil, RIL-dependent high and low support of bacterial growth was observed that was similar to results from experiments conducted in sterilized vermiculite. When uninoculated seeds from two of these RILs were planted in soil, changes in population levels of indigenous Bacillus and fluorescent Pseudomonas bacteria differed, as measured over time by culturing and direct microscopy, from growth patterns observed in the inoculation experiments. Neither RIL supported detectable levels of growth of indigenous Bacillus soil bacteria, while the line that supported growth of inoculated B. cereus UW85 supported higher growth of indigenous fluorescent pseudomonads and total bacteria. The vermiculite system used in these experiments was predictive for growth of B. cereus UW85 inoculated on seeds and grown in soil, but the patterns of growth of inoculated strains—both Bacillus and Pseudomonas spp.—did not reflect host genotype effects on indigenous microflora recruited from soil to the spermosphere.     

防己抑藻效应及其化感物质的HPLC分析

通过常温水浸提方法获得12种药用植物浸提液,并分别研究其抑藻效应。结果显示：防己水浸提物(相对浓度1 g·L^-1)抑制蛋白核小球藻的效应最强,最大比生长率为-0.28 d^-1。防己甲醇浸提物对蛋白核小球藻的抑藻效应显著,且持续时间长,最低有效抑藻浓度为30 mg·L^-1。HPLC鉴定结果显示：防己水浸提液和甲醇浸提液中主要含有防己诺林碱、粉防己碱等生物碱类化学成分,防己对治理水华发生有较大的应用前景。     

唐古特大黄药材提取物对小麦和垂穗披碱草种子萌发和幼苗生长的影响

测定了唐古特大黄（Rheum tanguticum Maxim. ex Balf.）药材水提液、蒽醌粗提液和多糖粗提液对小麦(Triticum aestivum Linn.)和垂穗披碱草（Elymus nutans Griseb.）种子萌发及幼苗生长的影响。结果表明：唐古特大黄药材水提液存在明显的化感作用,水提液在高浓度下对小麦种子萌发和芽长及垂穗披碱草种子萌发、根长和芽长均有明显的抑制作用,而在低浓度下对小麦的根长和芽长具有促进作用。蒽醌粗提液仅对垂穗披碱草幼苗生长有抑制作用,其作用随浓度的提高而增强。多糖处理液抑制了小麦、垂穗披碱草根的生长,同时高浓度的处理液延迟了垂穗披碱草种子发芽。     

Responses of Pinus halepensis growth, soil microbial catabolic functions and phosphate-solubilizing bacteria after rock phosphate amendment and ectomycorrhizal inoculation

We examined the effects of an ectomycorrhizal (EM) fungus, Pisolithus sp., on of the growth of Pinus halepensis (Allepo pine) seedlings, soil microbial functions and rock phosphate solubilization in a un-disinfected soil amended or not with a Moroccan rock phosphate. Allepo pine seedlings were inoculated with an EM fungus (Pisolithus sp. strain PH4) isolated from a P. halepensis plantation and selected for its high ability to mobilize P from an inorganic form of phosphate. After 4 month’s culture in a disinfected substrate, plants were transferred in 10 l-containers filled with a natural forest soil and amended or not with rock phosphate powder. After 12 month’s culturing, the growth, needle nutrient concentrations of P. halepensis plants were measured. Soil microbial catabolic diversity was assessed by measuring CO₂ production of substrate induced respiration responses. Fluorescent pseudomonads were isolated from each soil treatment and tested in axenic conditions for their ability to solubilize a source of inorganic phosphate. The results clearly showed that (i) P. halepensis growth was greatly promoted by the presence of the ectomycorrhizal fungus Pisolithus strain PH4 in a disinfected soil/vermiculite mixture and in a non disinfected soil, (ii) ectomycorrhizal inoculation induced significant changes in the functions of soil microbial communities and selected microorganisms potentially beneficial to the plant growth (i.e. phosphate-solubilizing fluorescent pseudomonad) and (iii) rock phosphate solubilisation was mainly dependent on EM inoculation and mycorrhizosphere microorganisms. These results were in accordance with previous studies where it was demonstrated that EM symbiosis has a beneficial effect on plant growth through a direct effect on the host plant but also an indirect effect via a selective pressure on soil microbiota that favours microorganisms potentially beneficial to plant growth.     

Endophytic bacteria isolated from orchid and their potential to promote plant growth

Twelve endophytic bacteria were isolated from the meristem of in vitro Cymbidium eburneum orchid, and screened according to indole yield quantified by colorimetric assay, in vitro phosphate solubilization, and potential for plant growth promotion under greenhouse conditions. Eight strains with positive results were classified into the genus Paenibacillus by FAME profile, and evaluated for their ability to increase survival and promote the growth of in vitro germinated Cattleya loddigesii seedlings during the acclimatization process. The obtained results showed that all strains produced detectable indole levels and did not exhibit potential for solubilizing inorganic phosphate. Particularly, an increase of the total biomass and number of leaves was observed. Two strains of Paenibacillus macerans promoted plant growth under greenhouse conditions. None of the treatments had a deleterious effect on growth of inoculated plants. These results suggest that these bacterial effects could be potentially useful to promote plant growth during seedling acclimatization in orchid species other than the species of origin.     

Endocellular fatty acid composition during batch growth and sporulation of Bacillus thuringiensis kurstaki

Bacillus thuringiensis kurstaki (HD-1) was grown on two different complex media to study its fatty acid composition during vegetative growth and sporulation. In contrast to literature results, iso-even branched-chain fatty acids were found to predominate after early vegetative growth and throughout sporulation.     

Comparative studies on the allelopathic effects of two different strains of Ulva pertusa on Heterosigma akashiwo and Alexandrium tamarense

Allelopathic effects of fresh tissue and dry powder of a nonsexual and a sexual strain of the macroalga Ulva pertusa on the growth of the microalgae Heterosigma akashiwo and Alexandium tamarense were evaluated using long-term coexistence culture systems in which several concentrations of macroalga fresh tissue and dry powder were used. The effects of macroalga culture medium filtrate on the two HAB algae were also investigated. Moreover, isolation co-culture systems were built to confirm the existence of allelochemicals and preclude the growth inhibition by direct contact. Short-term algicidal effect assays of macroalgae on H. akashiwo were carried out to measure the rate of algal cell lysis. The results of the coexistence assays showed that the growth of H. akashiwo and A. tamarense was strongly inhibited by fresh tissue and by dry powder of both strains of U. pertusa. The allelochemicals were lethal to H. akashiwo at relatively higher concentrations. The macroalga culture medium filtrate exhibited no apparent growth inhibitory effect on the two HAB algae under initial or semicontinuous filtrate addition, which suggested that continuous release of small quantities of rapidly degradable allelochemicals from the fresh tissue of both strains of U. pertusa was essential to effectively inhibit the growth of H. akashiwo and A. tamarense.     

Synthesis and discovery of pyrazole-5-carbohydrazide N-glycosides as inducer of autophagy in A549 lung cancer cells

A series of novel 3-aryl-1-arylmethyl-1H-pyrazole-5-carbohydrazide N-β-glycoside derivatives was synthesized by the reaction of substituted 1H-pyrazole-5-carbohydrazide with d-sugar and the effects of all the compounds on A549 cell growth were investigated. The results showed that all compounds had inhibitory effects on the growth of A549 lung cancer cells and compound 3d possessed the highest growth inhibitory effect and induced autophagy of A549 lung cancer cells.     

Relative effects of Justicia americana litter on germination,seedlings and established plants of Polygonum lapathifolium

Justicia americana (L.) Vahl is one of the most common species associated with seasonally variable aquatic habitats in the south-central U.S.A. When water levels decline, litter of Justicia decomposes on the exposed mudflats where most emergent aquatic species typically germinate and establish. In this study, we have tested the effects of aqueous leachates of Justicia shoots on the germination, seedling growth and established plant growth of Polygonum lapathifolium L., a common annual colonizer of exposed mudflats. Maximal leachate concentrations were prepared using quantities of litter comparable to those estimated for natural stands of Justicia. At these concentrations, seed germination and transplant growth were unaffected, but seedling growth was inhibited. When Polygonum was tested with lower concentrations of Justicia leachate, germination was still unaffected, but seedling growth was found to be enhanced, especially at the lowest concentrations. Using mannitol as an inert osmotic agent, Polygonum seedling growth was found to be inhibited at osmotic potentials equivalent to those of all leachate concentrations. Thus, the effects of leachate on seedling growth include both osmotic and non-osmotic components. Overall, the results support the hypothesis that the seedling stage of the plant life cycle is the stage most susceptible to permanent effects by the chemicals released from decomposing litter.     

Experimental and statistical analysis of nutritional requirements for the growth of the extremophile Deinococcus geothermalis DSM 11300

Few studies concerning the nutritional requirements of Deinococcus geothermalis DSM 11300 have been conducted to date. Three defined media compositions have been published for the growth of this strain but they were found to be inadequate to achieve growth without limitation. Furthermore, growth curves, biomass concentration and growth rates were generally not available. Analysis in Principal Components was used in this work to compare and consequently to highlight the main compounds which differ between published chemically defined media. When available, biomass concentration, and/or growth rate were superimposed to the PCA analysis. The formulations of the media were collected from existing literature; media compositions designed for the growth of several strains of Deinococcaceae or Micrococcaceae were included. The results showed that a defined medium adapted from Holland et al. (Appl Microbiol Biotechnol 72:1074–1082, 2006) was the best basal medium and was chosen for further studies. A growth rate of 0.03 h^?1 and a final OD_600nm of 0.55 were obtained, but the growth was linear. Then, the effects of several medium components on oxygen uptake and biomass production by Deinococcus geothermalis DSM 11300 were studied using a respirometry-based method, to search for the nutritional limitation. The results revealed that the whole yeast extract in the medium with glucose is necessary to obtain a non-limiting growth of Deinococcus geothermalis DSM 11300 at a maximum growth rate of 0.64 h^?1 at 45 °C.     

Radial growth response of major conifers to climate change on Haba Snow Mountain,Southwestern China

Climate change has an inevitable impact on forest ecosystems, to better understand the influence of climate change on forest growth, we analyzed the growth response of four major conifers to climate on Haba Snow Mountain in central Hengduan Mountains. Tree ring samples were taken from four species at their upper distributional limits, and residual chronologies were developed by using tree ring width data. Response function and redundancy analysis were taken to reveal the key climatic factors affecting tree growth and moving interval analysis was applied to detect the stability of growth-climate relationships. The results showed that previous November temperature, precipitation in current February, current May and current June were common factors affecting the radial growth of the studied species. Abies georgei was mainly influenced by the temperature in previous November. The photothermal condition in May and June controlled the growth of Larix potaninii. Moisture condition in previous August and current May was the key factor affecting Pinus densata growth. As for Pinus yunnanensis, the drought in current May was the limiting factor influencing its growth. The dynamic relationship between tree growth and climatic factors varied among species, and the results were consistent with response function analysis. A forecast in future forest growth on Haba Snow Mountain was complex, since future climate change had both positive and negative effects on the radial growth of four major conifers.     

Catabolism of naphthalene and salicylate byPseudomonas fluorescens

Analysis of spent naphthalene growth media ofPseudomonas fluorescens by GC-MS revealed the presence of salicylate. Gentisate 1,2-dioxygenase and pyrocatechol 1,2-dioxygenase were induced by growth on naphthalene, whereas only pyrocatechol 1,2-dioxygenase was induced during growth on salicylate. These results suggest the existence of alternative degradative routes of salicylate,via gentisate and pyrocatechol, which are involved in the catabolism of naphthalene.     

Effects of Interactions of Auxin-Producing Bacteria and Bacterial-Feeding Nematodes on Regulation of Peanut Growths

The influences of an IAA (indole-3-acetic acid)-producing bacterium (Bacillus megaterium) and two bacterial-feeding nematodes (Cephalobus sp. or Mesorhabditis sp.) on the growth of peanut (Arachis hypogaea L. cv. Haihua 1) after various durations of time were investigated in natural soils. The addition of bacteria and nematodes and incubation time all significantly affected plant growth, plant root growth, plant nutrient concentrations, soil nutrient concentrations, soil microorganisms and soil auxin concentration. The addition of nematodes caused greater increases in these indices than those of bacteria, while the addition of the combination of bacteria and nematodes caused further increases. After 42-day growth, the increases in soil respiration differed between the additions of two kinds of nematodes because of differences in their life strategies. The effects of the bacteria and nematodes on the nutrient and hormone concentrations were responsible for the increases in plant growth. These results indicate the potential for promoting plant growth via the addition of nematodes and bacteria to soil.     

Comparative Study of the Effects of Citral on the Growth and Injury of Listeria innocua and Listeria monocytogenes Cells

This study investigates the effect of citral on growth and on the occurrence of sublethal damage in Listeria innocua Serovar 6a (CECT 910) and Listeria monocytogenes Serovar 4b (CECT 4032) cells that were exposed to citral as a natural antimicrobial agent. Two initial inoculum concentrations were considered in this investigation: 10² and 10⁶ cfu/mL. Citral exhibited antilisterial activity against L. innocua and L. monocytogenes, and the observed effects were dependent on the concentration of citral present in the culture medium (0, 0.150 and 0.250 μL/mL) (p ≤ 0.05). L. innocua had a shorter lag phase than L. monocytogenes, and the two species had nearly identical maximum specific growth rates. These results indicate that L. innocua could be used as surrogate for L. monocytogenes when testing the effects of this antimicrobial. Significant differences in the lag phase and growth rate were observed between the small and large inoculum concentration (p ≤ 0.05). Citral-treated L. innocua and L. monocytogenes that were recovered on selective medium (i.e., TSA-YE-SC) had a shorter lag phase and a higher maximum specific growth rate than cells that were recovered on non-selective medium (i.e., TSA-YE) (p ≤ 0.05). This result suggests that damage occurs at sublethal concentrations of citral.     

光、温限制后铜绿微囊藻和斜生栅藻的超补偿生长与竞争效应

研究了铜绿微囊藻(Microcystis aeruginosa)和斜生栅藻(Scenedesmus obliquus)低温和低光照限制后的超补偿效应,以及共培养条件下的竞争效应。结果表明,低温和低光照均显著抑制微藻的生长发育,但低温对铜绿微囊藻的抑制效应更强,而斜生栅藻则对低光胁迫更敏感。经过低光和低温培养后,铜绿微囊藻和斜生栅藻在恢复正常培养时藻细胞密度短期内都表现出超补偿增长效应,但不同藻类超补偿模式不同,斜生栅藻补偿生长时间不超过1周,而铜绿微囊藻的补偿效应可以持续10天;此外,统计结果表明铜绿微囊藻细胞密度对低温限制解除表现出更显著的补偿生长,斜生栅藻则在低光解除后表现出更强的超补偿效应。微藻叶绿素a指标在光恢复条件下都表现出显著的补偿效应,但温度恢复过程中叶绿素a含量与藻密度增长不同步,低温胁迫对恢复正常培养后微藻叶绿素a的形成产生了一定的负效应;铜绿微囊藻产毒株(912)在两种恢复模式下脱氢酶活性显著高于对照,产毒株(912)脱氢酶活性的补偿响应明显高于其它两种材料。共培养实验结果表明斜生栅藻同铜绿微囊藻产毒株(912)相比处于竞争劣势,而在同无毒株(469)的共培实验中,尽管连续正常培养情况下两者竞争能力差异不显著,但在恢复培养条件下斜生栅藻竞争能力显著高于后者。因此产毒型铜绿微囊藻低温和低光后的补偿生长效应以及对斜生栅藻的竞争优势可能是蓝藻爆发的内源性机制之一。     

6-Gingerol Inhibits Hair Shaft Growth in Cultured Human Hair Follicles and Modulates Hair Growth in Mice

Ginger (Zingiber officinale) has been traditionally used to check hair loss and stimulate hair growth in East Asia. Several companies produce shampoo containing an extract of ginger claimed to have anti-hair loss and hair growth promotion properties. However, there is no scientific evidence to back up these claims. This study was undertaken to measure 6-gingerol, the main active component of ginger, on hair shaft elongation in vitro and hair growth in vivo, and to investigate its effect on human dermal papilla cells (DPCs) in vivo and in vitro. 6-Gingerol suppressed hair growth in hair follicles in culture and the proliferation of cultured DPCs. The growth inhibition of DPCs by 6-gingerol in vitro may reflect a decrease in the Bcl-2/Bax ratio. Similar results were obtained in vivo. The results of this study showed that 6-gingerol does not have the ability to promote hair growth, on the contrary, can suppress human hair growth via its inhibitory and pro-apoptotic effects on DPCs in vitro, and can cause prolongation of telogen phase in vivo. Thus, 6-gingerol rather than being a hair growth stimulating drug, it is a potential hair growth suppressive drug; i.e. for hair removal.     

Oxygen Requirements of the Food Spoilage Yeast Zygosaccharomyces bailii in Synthetic and Complex Media

Most yeast species can ferment sugars to ethanol, but only a few can grow in the complete absence of oxygen. Oxygen availability might, therefore, be a key parameter in spoilage of food caused by fermentative yeasts. In this study, the oxygen requirement and regulation of alcoholic fermentation were studied in batch cultures of the spoilage yeast Zygosaccharomyces bailii at a constant pH, pH 3.0. In aerobic, glucose-grown cultures, Z. bailii exhibited aerobic alcoholic fermentation similar to that of Saccharomyces cerevisiae and other Crabtree-positive yeasts. In anaerobic fermentor cultures grown on a synthetic medium supplemented with glucose, Tween 80, and ergosterol, S. cerevisiae exhibited rapid exponential growth. Growth of Z. bailii under these conditions was extremely slow and linear. These linear growth kinetics indicate that cell proliferation of Z. bailii in the anaerobic fermentors was limited by a constant, low rate of oxygen leakage into the system. Similar results were obtained with the facultatively fermentative yeast Candida utilis. When the same experimental setup was used for anaerobic cultivation, in complex YPD medium, Z. bailii exhibited exponential growth and vigorous fermentation, indicating that a nutritional requirement for anaerobic growth was met by complex-medium components. Our results demonstrate that restriction of oxygen entry into foods and beverages, which are rich in nutrients, is not a promising strategy for preventing growth and gas formation by Z. bailii. In contrast to the growth of Z. bailii, anaerobic growth of S. cerevisiae on complex YPD medium was much slower than growth in synthetic medium, which probably reflected the superior tolerance of the former yeast to organic acids at low pH.     

Effect of co-inoculation of methylotrophic Methylobacterium oryzae with Azospirillum brasilense and Burkholderia pyrrocinia on the growth and nutrient uptake of tomato, red pepper and rice

The present greenhouse study was undertaken to evaluate the effects of co-inoculating methylotrophic Methylobacterium oryzae CBMB20 along with nitrogen-fixing Azospirillum brasilense CW903 or a phosphate solubilizing bacterium Burkholderia pyrrocinia CBPB-HOD on the growth and nutrient uptake of tomato, red pepper and rice. Seed inoculation and soil/foliar application of the bacterial strains alone or under dual inoculation increased the plant growth in terms of shoot or root length and increased the nutrient uptake in the plants studied compared to uninoculated control plants. Co-inoculation of M. oryzae CBMB20 with A. brasilense CW903 or B. pyrrocinia CBPB-HOD improved the N and P concentration of plants, while the results varied among the plant species tested. Also, co-inoculation of the bacterial strains increased the activity of nitrogenase, urease and phosphatase enzymes in soil when compared to uninoculated control or individual inoculations. Though the inoculation effects were analyzed at an early stage of plant growth, the results conclusively suggest that M. oryzae being compatible with other microorganisms in the rhizosphere can potentially be used as individual inoculant or co-inoculated with other plant growth promoting bacteria to increase the production in sustainable agricultural systems.     

Effect of volatiles from bacteria and yeast on the growth and pigmentation of sapstain fungi

Sapstain fungi affect the appearance of wood due to colonisation by pigmented hyphae but without producing significant strength losses. This is due to the production of melanin in the fungal cell walls of the staining fungi. Any biological control strategy targeted against this type of deterioration would therefore be considered successful if it inhibited either fungal growth or pigment production. Previous work has established that specific bacterial and yeast isolates selected on the basis of agar screening studies could significantly reduce levels of staining in wood block tests. This paper presents the results of a study to examine the role of volatile organic compounds (VOCs) produced by four bacterial and three yeast isolates on the growth and pigment production by a range of five sapstain fungi on three media types. VOCs from three of the four bacterial strains tested completely inhibited growth of the five target sapstain fungi but only when the antagonists were grown on tryptone soya media. When antagonists were grown on either malt agar or a low nutrient medium levels of inhibition were either significantly reduced or non-existent. Yeast antagonists generally produced lower levels of growth inhibition than the bacteria but a Williopsis mrakii isolate gave 100% inhibition of three of the five sapstain fungi. Production of inhibitory VOCs was highly dependent on the specific antagonist as well as its growth substrate and all five sapstain fungi showed varying sensitivities to the VOCs produced. Not all fungi were inhibited, growth of O. piliferum and A. pullulans being stimulated by the VOCs from antagonists but only when grown under low nutrient conditions. In some instances, where growth was only slightly reduced, the level of pigmentation of the sapstain colony was significantly reduced compared with corresponding controls. The implications of this work for the biological control of sapstain fungi are discussed.     

Potential of pure and mixed cultures of Cladosporium cladosporioides and Geotrichum candidum for application in bioremediation and detergent industry

The effect of ethoxylated oleyl–cetyl alcohol (Henkel, “Merima”, Serbia) on the growth and metabolic activity of Cladosporium cladosporioides, Geotrichum candidum and their mixed culture was in the focus of this paper. The cultures were grown in Czapek-Dox liquid nutrient medium with the addition of 0.5% pollutant and without it. The physico-chemical and biochemical changes of pH, the total biomass dry weight, the quantity of free and total organic acids, proteolytic activity and the quality of carbohydrates were evaluated from 4th to 19th day of fungal growth. The pollutant caused an inhibitory effect on biomass dry weight of C. cladosporioides and G. candidum for 10.36% and 4.65% respectively, and stimulatory effect on biomass of mixed culture for 3.80%. The pollutant had influence on the decrease in pH value of the media in the phase of culture growth, and pH changes were correlated with the amount of excreted total organic acids. The highest quantity of free and total organic acids was noted in media with pollutant of mixed culture and C. cladosporioides, respectively. The alkaline protease activities of C. cladosporioides, G. candidum and mixed culture were enhanced by addition of pollutant for 56.88%, 55.84% and 30.94% respectively. The obtained results indicate the potential of both pure and mixed cultures in mycoremediation environment contaminated by alcohol ethoxylated and detergent industry.