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991.
Botulinum neurotoxins type A (BoNT/A) are highly potent toxins, but are also useful in the treatment of illnesses. We studied
the properties of BoNT/A at various temperatures and pH values in order to understand its toxicity and structure variations.
The pH values of the environment of BoNT/A are obtained by changing the protonation states of certain titratable residue groups.
Our results show that certain parts of the protein are active at acidic pH environments or at high temperatures. The protein
is more stable in neutral environments at normal human body temperature, whereas, at high temperature, the protein is more
stable in acidic environments. Also, the three domains of the protein tend to have relative motion rather than within individual
domains. 相似文献
992.
Uchii Kimiko Wakimura Kei Kikko Takeshi Yonekura Ryuji Kawaguchi Riho Komada Honoka Yamanaka Hiroki Kenzaka Takehiko Tani Katsuji 《Limnology》2022,23(1):49-56
Limnology - Gnathopogon caerulescens is an endangered but commercially important fish in Lake Biwa, Japan. The population size of G. caerulescens has drastically reduced in the past decades, and... 相似文献
993.
Takeshi Kikko Daisuke Ishizaki Taiga Yodo Shizuo Aino Kunihiko Kuwamura Haruo Okamoto Morihito Nemoto Kazuki Yoneda Nobuyuki Oue Akihisa Sakai Yasuhiro Fujioka Yoshiaki Kai Takuya Sato Kouji Nakayama 《Journal of fish biology》2019,95(2):668-672
Otolith growth increments in wild-caught alizarin complex one (ALC)-marked honmoroko Gnathopogon caerulescens were examined to verify the veracity of the age determination method in cyprinids. ALC-marked G. caerulescens recaptured from their natural environment had lapilli increment counts outside the ALC ring mark that had formed on a daily basis during the juvenile stage. This apparently being the first direct evidence of daily periodicity of otolith increment formation in wild-caught cyprinids. 相似文献
994.
995.
996.
Rachel Schell Joseph J Hale Martin N Mullis Takeshi Matsui Ryan Foree Ian M Ehrenreich 《Genetics》2022,220(3)
Genetic background often influences the phenotypic consequences of mutations, resulting in variable expressivity. How standing genetic variants collectively cause this phenomenon is not fully understood. Here, we comprehensively identify loci in a budding yeast cross that impact the growth of individuals carrying a spontaneous missense mutation in the nuclear-encoded mitochondrial ribosomal gene MRP20. Initial results suggested that a single large effect locus influences the mutation’s expressivity, with 1 allele causing inviability in mutants. However, further experiments revealed this simplicity was an illusion. In fact, many additional loci shape the mutation’s expressivity, collectively leading to a wide spectrum of mutational responses. These results exemplify how complex combinations of alleles can produce a diversity of qualitative and quantitative responses to the same mutation. 相似文献
997.
Takeshi Izuta 《Journal of plant research》1998,111(4):471-480
In this review, I summarized the results obtained from experimental studies on the ecophysiological responses of Japanese
forest tree species to O3, simulated acid rain and soil acidification. Based on the studies conducted in Japan, exposure to ambient levels of O3 below 100 nl·l−1 (ppb) for several months is sufficient to inhibit dry matter production and net photosynthesis of sensitive Japanese forest
tree species such as Siebold's beech and Japanese zelkova. On the other hand, exposure to simulated acid rain with a pH of
4.0 or above for several months cannot induce any adverse effects on dry matter production and physiological functions of
Japanese forest tree species. However, when the pH of simulated rain or fog is lowered below 4.0, negative effects appear
on dry matter production and physiological functions such as transpiration in several sensitive Japanese forest tree species
such as Japanese fir and Nikko fir. Based on limited information, it may be concluded that (1) Al dissolved into soil solution
is the most important limiting factor for dry matter production, physiological functions and nutrient status of Japanese forest
tree species grown in acidic soil, (2) the (Ca+Mg+K)/Al molar ratio in soil solution is a useful indicator to evaluate and
predict the effects of soil acidification due to acid deposition on whole-plant dry matter production of Japanese forest tree
species at the present time and in the future, and (3) Japanese coniferous tree species such as Japanese cedar and red pine
are relatively sensitive to a reduction in (Ca+Mg+K)/Al molar ratio in soil solution compared with European forest tree species
such as Norway spruce. 相似文献
998.
Mutsumi Nakamura Takafumi Nagamine Chisato Harada Kiyoshi Tajima Hiroki Matsui Yoshimi Benno 《Current microbiology》2003,47(1):0071-0074
The objective of this study was to ligate the xylanase gene A (xynA) isolated from Ruminococcus albus 7 into the promoter and signal-peptide region of the lichenase [β-(1,3-1,4)-glucanase] gene of Streptococcus bovis JB1. This fusion gene was inserted into the pSBE11 vector, and the resulting recombinant, plasmid pXA, was used to transform
S. bovis 12-U-1 cells. The transformant, S. bovis 12UXA, secreted the xylanase, which was stable against freeze-thaw treatment and long-time incubation at 37°C. The introduction
of pXA and production of xylanase did not affect cell growth, and the xylanase produced degraded xylan from oat-spelt and
birchwood.
Received: 24 June 2002 / Accepted: 7 October 2002 相似文献
999.
We investigated the mycorrhizal status of perennial xeric plant species occurring in the "matorral xerófilo" (arid tropical scrub) and the ecotone of the "selva baja caducifolia" (tropical deciduous forest) communities in the semiarid valley of Tehuacán-Cuicatlán, south-central Mexico. The perennial species examined are dominant/codominant elements within the "matorral xerófilo" and the "selva baja caducifolia", both endangered communities in the Biosphere Reserve Tehuacán-Cuicatlán Valley. Of the 50 sampled species, 45 were mycorrhizal. To our knowledge, we report arbuscular mycorrhizae (AM) for the first time in 37 species, of which 21 are endemic to Mexico and nine are endemic to the Valley. We also report AM for the first time in three genera, Buddleja, Hechtia and Zornia, and in one plant family, Buddlejaceae. Beaucarnea gracilis, a threatened species, and Mimosa purpusii, a potentially rare species, are both mycorrhizal. This is the first study of the mycorrhizal status of plant species within the Valley. 相似文献
1000.
Luis Giménez 《Helgoland Marine Research》2003,56(4):265-273
Chasmagnathus granulata is a South American crab occurring in estuarine salt marshes of the Brazilian, Uruguayan and Argentine coasts. Life history
is characterized by an export strategy of its larval stages. I reviewed information on experimental manipulation of salinity
during embryonic and larval development (pre- and posthatching salinities), and on habitat characteristics of C. granulata in order to determine potential effects of larval response to salinity in the field and to suggest consequences for the population
structure. Local populations are spread over coastal areas with different physical characteristics. Benthic phases occupy
estuaries characterized by different patterns of salinity variation, and release larvae to coastal waters characterized by
strong salinity gradients. The zoea 1 of C. granulata showed a strong acclimatory response to low salinity. This response operated only during the first weeks of development (during
zoeae 1 and 2) since subsequent larval survival at low posthatching salinities was consistently low. Larvae developing at
low salinity frequently followed a developmental pathway with five instead of four zoeal stages. The ability to acclimate
and the variability in larval development (i.e. the existence of alternative developmental pathways) could be interpreted
as a strategy to buffer environmental variability at spatial scales of local or population networks. Early survivorship and
production of larvae may be relatively high across a rather wide range of variability in salinity (5–32‰). Plastic responses
to low salinity would therefore contribute to maintain a certain degree of population connectivity and persistence regardless
of habitat heterogeneity.
Electronic Publication 相似文献