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981.
Md. Mahabubur Rahman Muhammad Nurul Amin Futoshi Ishiguri Shinso Yokota Rubaiyat Sharmin Sultana Yuya Takashima Kazuya Iizuka Nobuo Yoshizawa 《Plant biotechnology reports》2009,3(3):259-266
A plantlet regeneration protocol was developed on pot-grown mature plants of Elaeocarpus robustus Roxb. cv. Dwarf from nodal and leaf explants. The best yield of adventitious shoots was achieved from the leaf-derived calli
in a modified MS (MMS1, half strength of major salts, full strength of minor salts, and vitamins) medium containing 4.0 μM BA + 4.0 μM Kn + 0.5 μM
NAA + 15% coconut water (CW). The shoot multiplication rate was amplified about twofold per culture after the addition of
15% CW to the medium. The rate of shoot multiplication reached maximum at the 5th subculture, and it maintained this rate
throughout the 3 subsequent subcultures. The best rooting in vitro was investigated by subculturing the microcuttings in an
MMS2 (half strength of both major salts and minor salts and full strength of vitamins) medium containing 1.0 μM IBA in the dark
for one initial week at 30°C, followed by subculturing them in a plant-growth regulator (PGR)-free medium in the light. The
plantlets raised in vitro were successfully established under ex vitro conditions. 相似文献
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985.
Transmission routes maintaining a viral pathogen of steelhead trout within a complex multi‐host assemblage
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Rachel Breyta Paige Ferguson Gael Kurath Kerry A. Naish Maureen K. Purcell Andrew R. Wargo Shannon LaDeau 《Ecology and evolution》2017,7(20):8187-8200
This is the first comprehensive region wide, spatially explicit epidemiologic analysis of surveillance data of the aquatic viral pathogen infectious hematopoietic necrosis virus (IHNV) infecting native salmonid fish. The pathogen has been documented in the freshwater ecosystem of the Pacific Northwest of North America since the 1950s, and the current report describes the disease ecology of IHNV during 2000–2012. Prevalence of IHNV infection in monitored salmonid host cohorts ranged from 8% to 30%, with the highest levels observed in juvenile steelhead trout. The spatial distribution of all IHNV‐infected cohorts was concentrated in two sub‐regions of the study area, where historic burden of the viral disease has been high. During the study period, prevalence levels fluctuated with a temporal peak in 2002. Virologic and genetic surveillance data were analyzed for evidence of three separate but not mutually exclusive transmission routes hypothesized to be maintaining IHNV in the freshwater ecosystem. Transmission between year classes of juvenile fish at individual sites (route 1) was supported at varying levels of certainty in 10%–55% of candidate cases, transmission between neighboring juvenile cohorts (route 2) was supported in 31%–78% of candidate cases, and transmission from adult fish returning to the same site as an infected juvenile cohort was supported in 26%–74% of candidate cases. The results of this study indicate that multiple specific transmission routes are acting to maintain IHNV in juvenile fish, providing concrete evidence that can be used to improve resource management. Furthermore, these results demonstrate that more sophisticated analysis of available spatio‐temporal and genetic data is likely to yield greater insight in future studies. 相似文献
986.
Oral application of Escherichia coli bacteriophage: safety tests in healthy and diarrheal children from Bangladesh
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Shafiqul Alam Sarker Bernard Berger Ying Deng Silas Kieser Francis Foata Deborah Moine Patrick Descombes Shamima Sultana Sayeeda Huq Pradip Kumar Bardhan Valérie Vuillet Fabienne Praplan Harald Brüssow 《Environmental microbiology》2017,19(1):237-250
A T4‐like coliphage cocktail was given with different oral doses to healthy Bangladeshi children in a placebo‐controlled randomized phase I safety trial. Fecal phage detection was oral dose dependent suggesting passive gut transit of coliphages through the gut. No adverse effects of phage application were seen clinically and by clinical chemistry. Similar results were obtained for a commercial phage preparation (Coliproteus from Microgen/Russia). By 16S rRNA gene sequencing, only a low degree of fecal microbiota conservation was seen in healthy children from Bangladesh who were sampled over a time interval of 7 days suggesting a substantial temporal fluctuation of the fecal microbiota composition. Microbiota variability was not associated with the age of the children or the presence of phage in the stool. Stool microbiota composition of Bangladeshi children resembled that found in children of other regions of the world. Marked variability in fecal microbiota composition was also seen in 71 pediatric diarrhea patients receiving only oral rehydration therapy and in 38 patients receiving coliphage preparations or placebo when sampled 1.2 or 4 days apart respectively. Temporal stability of the gut microbiota should be assessed in case‐control studies involving children before associating fecal microbiota composition with health or disease phenotypes. 相似文献
987.
Evolution lacks foresight, and hence, key adaptations may produce major challenges over the long run. The natural world is rife with examples of long‐term ‘side effects’ associated with quick‐fix tinkering, including blind spots in vertebrate eyes. An important question is how nature compensates for imperfections once evolution has set a course. The symbioses associated with sap‐feeding insects present a fascinating opportunity to address this issue. On one hand, the substantial diversity and biomass of sap‐feeding insects are largely due to ancient acquisitions of nutrient‐provisioning bacterial symbionts. Yet, the insularity and small population sizes enforced by intracellular life and strict maternal transfer inevitably result in the degradation of symbiont genomes and, often, the beneficial services that symbionts provide. Stabilization through lateral transfer of bacterial genes into the host nucleus (often from exogenous sources) or replacement of the long‐standing symbiont with a new partner are potential solutions to this evolutionary dilemma (Bennett & Moran 2015 ). A third solution is adoption of a cosymbiont that compensates for specific losses in the original resident. Ancient ‘co‐obligate’ symbiont pairs in mealybugs, leafhoppers, cicadas and spittlebugs show colocalization, codiversification, metabolite exchange and generally nonredundant nutrient biosynthesis (Bennett & Moran 2015 ). But in this issue, Meseguer et al. ( 2017 ) report on a different flavour of cosymbiosis among conifer‐feeding Cinara aphids. 相似文献
988.
Zachary R. King Silas P. Childs Donna K. Harris Kerry F. Pedley James W. Buck H. Roger Boerma Zenglu Li 《Molecular breeding : new strategies in plant improvement》2017,37(5):62
Phakopsora pachyrhizi is a fungal pathogen and the cause of Asian soybean rust. P. pachyrhizi was first detected in the continental USA in 2004 and has since been a threat to the soybean industry. There are six described loci that harbor resistance to P. pachyrhizi (Rpp) genes. The resistance of PI 423972 was previously shown to be within 5 cM of the Rpp4 locus of PI 459025B, yet had differential reactions when challenged with P. pachyrhizi isolates India 1973 and Taiwan 1972. In this study, the resistance of PI 423972 was mapped to a 187.5 kb interval between the SNP markers GSM0543 and GSM0387 on chromosome 18 (51,397,064 to 51,584,617 bp, Glyma.Wm82.a2) that overlaps the interval for Rpp4 and is designated as Rpp4-b. A unique haplotype is described for PI 423972 that separates it from PI 459025B, 32 North American soybean ancestors, and all described sources of Rpp gene resistance. 相似文献
989.
990.
Abiotic influences on bicarbonate use in the giant kelp,Macrocystis pyrifera,in the Monterey Bay
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In the Monterey Bay region of central California, the giant kelp Macrocystis pyrifera experiences broad fluctuations in wave forces, temperature, light availability, nutrient availability, and seawater carbonate chemistry, all of which may impact their productivity. In particular, current velocities and light intensity may strongly regulate the supply and demand of inorganic carbon (Ci) as substrates for photosynthesis. Macrocystis pyrifera can acquire and utilize both CO2 and bicarbonate (HCO3?) as Ci substrates for photosynthesis and growth. Given the variability in carbon delivery (due to current velocities and varying [DIC]) and demand (in the form of saturating irradiance), we hypothesized that the proportion of CO2 and bicarbonate utilized is not constant for M. pyrifera, but a variable function of their fluctuating environment. We further hypothesized that populations acclimated to different wave exposure and irradiance habitats would display different patterns of bicarbonate uptake. To test these hypotheses, we carried out oxygen evolution trials in the laboratory to measure the proportion of bicarbonate utilized by M. pyrifera via external CA under an orthogonal cross of velocity, irradiance, and acclimation treatments. Our Monterey Bay populations of M. pyrifera exhibited proportionally higher external bicarbonate utilization in high irradiance and high flow velocity conditions than in sub‐saturating irradiance or low flow velocity conditions. However, there was no significant difference in proportional bicarbonate use between deep blades and canopy blades, nor between individuals from wave‐exposed versus wave‐protected sites. This study contributes a new field‐oriented perspective on the abiotic controls of carbon utilization physiology in macroalgae. 相似文献