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1.
Sato T Shimizu Y Kano M Suzuki T Kanetaka H Chu LW Côté PD Shimauchi H Ichikawa H 《Cellular and molecular neurobiology》2011,31(1):155-161
The distribution of calcitonin gene-related peptide (CGRP) was examined in skeletal muscles of fore and hind limb as well
as in oral and cranio-facial regions of the degenerating muscle (dmu) mouse, which harbours a null mutation in the voltage-gated sodium channel gene Scn8a. In limb, oral and cranio-facial muscles of wild type mice, only a few motor endplates contained CGRP-immunoreactivity. However,
many CGRP-immunoreactive motor endplates appeared in the triceps brachii muscle, the biceps brachii muscle, the brachialis
muscle, and the gastrocnemius muscle of dmu mice. CGRP-immunoreactive density of motor endplates in the skeletal muscles was also elevated by the mutation. In these
muscles, the atrophy of muscle fibers could be detected and the density of cell nuclei in the musculature increased. In the
flexor digitorum profundus muscle, the flexor digitorum superficialis muscle, and the soleus muscle as well as in oral and
cranio-facial muscles, however, the distribution of CGRP-immunoreactivity was barely affected by the mutation. The morphology
of muscle fibers and the distribution of cell nuclei within them were also similar in wild type and dmu mice. In the lumbar spinal cord of dmu mice, CGRP-immunoreactive density of spinal motoneurons increased. These findings suggest that the atrophic degeneration
in some fore and hind limb muscles of dmu mice may increase CGRP expression in their motoneurons. 相似文献
2.
Agbeko Kodjo Tounou Christiann Kooyman Ouro Kobi Douro-Kpindou Hans Michael Poehling 《BioControl》2008,53(5):813-828
Field trials were conducted to evaluate the efficacy of wheat bran bait formulations of Paranosema locustae and Metarhizium anisopliae for controlling grasshoppers in southeast Niger. Treatments consisted of wheat bran baits mixed with M. anisopliae, P. locustae + M. anisopliae or with P. locustae spores and P. locustae + sugar. Oedaleus senegalensis, Pyrgomorpha cognata and Acrotylus blondeli were the predominant species at the time of application representing ca. 94% of the total population. Bran application was
done when O. senegalensis (ca. 75% of the population) was at its early developmental stages, with first, second and third instars accounting for 64–85%.
Grasshopper population reduction, P. locustae prevalence and level of infections in the predominant species were monitored. Manual application of P. locustae and M. anisopliae formulated in wheat bran has proven to induce consistent pathogen infection in grasshopper populations. Population density
over the three weeks monitoring, typically decreased by 44.7 ± 6.9%, 52.8 ± 8.4%, 73.7 ± 5.5% and 89.1 ± 1.8% in P. locustae, P. locustae + sugar, M. anisopliae and P. locustae + M. anisopliae treated plots respectively. Paranosema locustae prevalence in surviving adult grasshoppers at 28 after application was 48.1 ± 2.3%, 28.9 ± 4.8% and 27.4 ± 3.7%, with infection
level of 6.2 ± 0.8 × 106, 2.3 ± 0.3 × 104 and 2.1 ± 0.3 × 103 spores mg−1 host weight in O. senegalensis, A blondeli and P. cognate respectively. Other species that each accounted for <2% of the community, namely Aiolopus thalassinus, A. simulatrix, Acorypha glaucopsis, Acrotylus patruelis, Anacridium melanorhodon, Diabolocatantops axillaris, Kraussaria angulifera and Schistocerca gregaria were found to show sign of infection. The results from this study suggest that wheat bran application of M. anisopliae and P. locustae alone or in combination, targeting early instars grasshopper could be a valuable option in grasshopper control programs. 相似文献
3.
Ruxandra F. Sîrbulescu Iulian Ilieş Günther K. H. Zupanc 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》2009,195(7):699-714
In contrast to mammals, teleost fish exhibit an enormous potential to regenerate adult spinal cord tissue after injury. However,
the mechanisms mediating this ability are largely unknown. Here, we analyzed the major processes underlying structural and
functional regeneration after amputation of the caudal portion of the spinal cord in Apteronotus leptorhynchus, a weakly electric teleost. After a transient wave of apoptotic cell death, cell proliferation started to increase 5 days
after the lesion and persisted at high levels for at least 50 days. New cells differentiated into neurons, glia, and ependymal
cells. Retrograde tract tracing revealed axonal re-growth and innervation of the regenerate. Functional regeneration was demonstrated
by recovery of the amplitude of the electric organ discharge, a behavior generated by spinal motoneurons. Computer simulations
indicated that the observed rates of apoptotic cell death and cell proliferation can adequately explain the re-growth of the
spinal cord.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
4.
Alien plant species, such as Caulerpa racemosa var. cylindracea, that invade Mediterranean marine vegetated habitats can affect habitat structure. In turn, changes in habitat structure
may affect the associated invertebrate assemblages, either through changes in habitat selection or as a result of altered
predation efficiency. In order to test for effects of changes in habitat structure resulting from colonization by C. racemosa on prey availability for predators, the importance of amphipods as a trophic resource in natural vegetated habitat was first
assessed, and later experiments were undertaken to assess the effects of the alien alga on predation by Thalassoma pavo of two dominant amphipods: Elasmopus brasiliensis (Gammaridea) and Caprella dilatata (Caprellidea). Laboratory experiments were conducted in separate aquaria with five vegetation habitat types: Halopteris scoparia, Jania rubens, C. racemosa without detritus, C. racemosa with detritus, Cymodocea nodosa, together with controls. The vegetation was first defaunated, and then 30 amphipods were introduced to each aquarium and
exposed to a single Thalassoma pavo individual for 1 h, after which the fish’s gut contents were examined. Consumption (per fish per hour) of caprellids (11.7 ± 1.4)
was higher overall than that of gammarids (8.7 ± 1.5) and likely reflects different microhabitat use by amphipods, which affects
susceptibility to predators. Consumption of amphipods also varied by habitat type. The highest predation rate was found in
the C. nodosa habitat (12.7 ± 2.19) and the lowest in the C. racemosa habitats with detritus (4.1 ± 1.78) and without detritus (5.2 ± 0.55), which did not differ. The pattern of predation across
habitats, however, was similar for both caprellid and gammarid amphipods, indicating a more general effect of habitat on amphipod
predation. Our findings showed that invasive species such as C. racemosa can decrease feeding by predators such as T. pavo. Changes in predator–prey interactions could have consequences for food web support in the Mediterranean. 相似文献
5.
Konstantin V. Kiselev Anna V. Turlenko Yuri N. Zhuravlev 《Plant Cell, Tissue and Organ Culture》2009,99(2):141-149
A somatic embryogenesis protocol for plant regeneration of northern red oak (Quercus rubra) was established from immature cotyledon explants. Embryogenic callus cultures were induced on Murashige and Skoog medium
(MS) containing 3% sucrose, 0.24% Phytagel™, and various concentrations of 2,4-dichlorophenoxyacetic acid (2,4-d) after 4 weeks of culture in darkness. A higher response (66%) of embryogenic callus was induced on 0.45 μM 2,4-d. Higher numbers of globular- (31), heart- (17), torpedo- (12), and cotyledon-stage (8) embryos per explant were obtained
by culturing embryogenic callus on MS with 3% sucrose, 0.24% Phytagel™, and devoid of growth regulators after 8 weeks culture
in darkness. Continuous sub-culturing of embryogenic callus on medium containing 2,4-d yielded only compact callus. Desiccation of embryos for 3 days in darkness at 25 ± 2°C followed by cold storage at 4°C in
darkness for 8 weeks favored embryo germination and development of plantlets. Cotyledon-stage embryos subjected to desiccation
and chilling treatment cultured on MS with 3% sucrose, 0.24 Phytagel™, 0.44 μM 6-benzylaminopurine (BA), and 0.29 μM gibberellic
acid germinated at a higher frequency (61%) than with 0.44 μM BA alone and control cultures. Germinated plantlets developed
a shoot and root, were acclimatized successfully, and maintained in a growth room for plantlet development. 相似文献
6.
Katarina Stefanidesova Elena Kocianova Vojtech Boldis Zina Kostanova Pavel Kanka Danka Nemethova Eva Spitalska 《European Journal of Wildlife Research》2008,54(3):519-524
The purpose of this study was to investigate the role of wild animals for Anaplasma phagocytophilum, other ehrlichiae/anaplasmae, Rickettsia helvetica and other rickettsiae and whether different genetic variants of A. phagocytophilum in central Slovakia exist. A total of 109 spleen samples from 49 red deer (Cervus elaphus), 30 roe deer (Capreolus capreolus), 28 wild boar (Sus scrofa) and two mouflon (Ovis musimon) were collected from June 2005 to December 2006. Polymerase chain reaction (PCR) amplification of the16S rRNA gene was used
for detection of ehrlichiae/anaplasmae. A nested PCR targeting part (392 bp) of groESL gene was applied for the specific detection of A. phagocytophilum. Fragments of the gltA and ompA genes (381 bp and 632 bp, respectively) were amplified to detect rickettsiae, followed by sequencing. A. phagocytophilum and R. helvetica were detected in wild animals. The prevalence of A. phagocytophilum was 50.0 ± 18.2% in roe deer and 53.1 ± 14.1% in red deer. None of the 28 wild boar was PCR positive for ehrlichiae/anaplasmae.
A. phagocytophilum was detected in one mouflon. R. helvetica was found in one roe deer. Our study suggests a role of cervids as a natural reservoir of A. phagocytophilum in Slovakia. However, the role of cervids and wild boars in the circulation of R. helvetica remains unknown. The analysis of sequence variation in the msp4 coding region of A. phagocytophilum showed the presence of different variants previously described in ruminants. 相似文献
7.
X. Wei Y. S. Jiang S. Y. Jiang X. X. Qi Z. C. Xiong W. H. Ye Z. M. Wang 《Photosynthetica》2008,46(2):312-314
Saturation (SI) and compensation (CI) irradiances [μmol(photon) m−2 s−1] were 383.00±18.40 and 12.95±0.42 for wild C. nitidissima (in mid-July) and 691.00±47.39 and 21.91±1.28 for wild C. sinensis, respectively. C. nitidissima is a shade tolerant species, whereas C. sinensis has a wide ecological range of adaptability to irradiance. Both wild and cultivated C. nitidissima demonstrated low maximum net photosynthetic rate, maximum carboxylation rate, maximum electron transfer rate, and SI, which
indicated low photosynthesis ability of leaves that were unable to adapt to strong irradiance environment. Both C. nitidissima and C. sinensis demonstrated strong photosynthetic adaptabilty in new environments. Hence proper shading may raise photosynthetic efficiency
of cultivated C. nitidissima and promote its growth. 相似文献
8.
Cuiping Yuan Guoan Zhou Yinghui Li Kejing Wang Zhi Wang Xianghua Li Ruzhen Chang Lijuan Qiu 《Molecular breeding : new strategies in plant improvement》2008,22(4):593-602
Soybean cyst nematode (SCN) (Heterodera glycines Ichinohe) is the most important pathogen in soybean production worldwide and causes substantial yield losses. An apparent
narrow genetic base of SCN resistance was observed in current elite soybean cultivars, and searching for novel SCN resistance
genes as well as novel resistance sources rather than focusing on the two important genes rhg1 and Rhg4 has become another major objective in soybean research. In the present paper we report a 1,477 bp Hs1
pro-1
homolog, named GmHs1
pro-1
. This gene was cloned from soybean variety Wenfeng 7 based on information for Hs1
pro-1
, a beet cyst nematode resistance gene in sugar beet. It has two domains, Hs1pro-1_N and Hs1pro-1_C, both of which are believed
to confer resistance to nematodes. Of the 1,477 bp sequence in GmHs1
pro-1
, an open reading frame of 1,314 bp, encoding a protein with 437 amino acids, was flanked by a 5′-untranslated region of 27 bp
and a 3′-untranslated region of 135 bp. Fourteen single-nucleotide polymorphisms (SNPs) were observed in 44 soybean accessions
including 23 wild soybeans, 8 landraces, and 13 soybean varieties (or lines), among which 5 in wild soybeans and 3 in landrace
accessions were unique. Sequence diversity analysis on the 44 soybean accessions showed π = 0.00168 and θ = 0.00218 for GmHs1
pro-1
; landraces had the highest diversity, followed by wild soybeans, with varieties (or lines) having the lowest. Although we
did not detect a significant effect of selection on GmHs1
pro-1
in the three populations, sequence diversity, unique SNPs, and phylogenetic analysis indicated a slight domestication bottleneck
and an intensive selection bottleneck. High sequence diversity, more unique SNPs, and broader representation across the phylogenetic
tree in wild soybeans and landraces indicated that wild collections and landrace accessions are invaluable germplasm for broadening
the genetic base of elite soybean varieties resistant to SCN.
C. Yuan and G. Zhou contributed to this paper equally. 相似文献
9.
Quan-le Xu Zhe Hu Chun-yuan Li Xin-yu Wang Chong-ying Wang 《In vitro cellular & developmental biology. Plant》2009,45(5):583-590
Two protocols were developed for the efficient regeneration of Sinningia speciosa from leaf explants via two developmental pathways. The first method involved formation of callus and buds, followed by subsequent
root growth, in Murashige and Skoog medium (MS) containing 2.0 mg l−1 6-benzylaminopurine (BA) and 0.2 mg l−1 α-naphthalene acetic acid (NAA), with a regeneration efficiency of 99.0%. The second method involved producing callus and
roots, followed by subsequent formation of buds, in MS medium supplemented with 1.0–5.0 mg l−1 NAA, and resulted in a regeneration efficiency of 90.4%. Our experiments indicate that the root-first pathway resulted in
a lower plant regeneration efficiency. Through five continual generations using the buds-first method, a total of 215 regenerated
plants were obtained in the last generation, and eight exhibited a phenotype we named tricussate whorled phyllotaxis (twp). Six of the regenerated twp variant plants maintained their tricussate whorled phyllotaxis phenotype, showing no other abnormalities, while one reverted
to a wild type before flowering and another formed two rounds of sepals. Physiological analysis revealed that the twp plants responded differently than wild type to exogenous NAA and 2,3,5-triiodobenzoic acid (TIBA), while high-performance
liquid chromatography (HPLC) analysis showed that the levels of endogenous indole-3-acetic acid (IAA) and gibberellin (GA)
were lower in twp than wild-type plants. These results suggest that the formation of the twp mutant may be related to phytohormones and that the twp variant could be an important material for investigating the molecular mechanism of plant phyllotaxis patterning. 相似文献
10.
11.
Andrea Franzetti Isabella Gandolfi Marco Piscitello Giovanni Porto Adriano Biasiolo Francesca Oltolini Tomaso Marangoni Giuseppina Bestetti 《Biodegradation》2010,21(2):193-201
The effectiveness of biosparging to mitigate N,N diethylaniline in aquifer was evaluated by measuring the time course of decrease in concentration of the aforementioned compound
in aerobic microcosm experiments. The first-order kinetic constant for N,N diethylaniline aerobic biodegradation was estimated from microcosm data (0.037 ± 0.004 d−1), and the value was consistent with the best-fitting value in the transport and reaction model of the aquifer (0.020 d−1). Furthermore, the biodegradability of the compound was evaluated under anaerobic condition in microcosm experiments, which
was supported by field modelling. There was no significant degradation in the anaerobic microcosm experiments, confirming
the recalcitrance of N,N diethyl aniline under the aforementioned aquifer condition. 相似文献
12.
D. C. Peñalva-Arana Kenneth Forshay Pieter T. J. Johnson J. R. Strickler Stanley I. Dodson 《Hydrobiologia》2011,668(1):147-154
Zooplankters are hosts to numerous endo- and ectoparasites, some of which have dramatic impacts on their hosts. Epizootics
on zooplankton are probably more widespread in lake systems than it is currently known, and few studies have explored the
direct and indirect importance of parasitism in aquatic food webs. In addition, our understanding of the sublethal effects
of parasitic infections on host organisms and populations is limited. We used a novel electro-chemical based technique to
measure in the outflow of the feeding current changes in the beat rate of the thoracic appendages in female Daphnia pulicaria. We observed simultaneously the heart rates and compared chytrid infected animals with uninfected gravid and non-gravid ones.
We found in uninfected animals a thoracic beat rate of 3.81 ± 018 Hz and a heart rate of 4.67 ± 0.42 Hz. Gravid daphnids had
a 14% lower thoracic beat rate (3.27 ± 0.30 Hz) than non-gravid females while the heart rate did not significantly differ
(4.48 ± 0.28 Hz). In contrast, infected animals showed a 22% lower thoracic beat rate (2.96 ± 0.47 Hz) and a 36% lower heart
rate (2.98 ± 0.5 Hz) when compared with uninfected non-gravid females. We discuss the ways Daphnia are affected by Polycaryum leave infections on the individual and population level. 相似文献
13.
The structural gene for sphingomyelinase (SMase) from Streptomyces
griseocarneus, was introduced into Streptomyces lividans using a shuttle vector, pUC702, for Escherichia coli/S. lividans. High-level secretory production of SMase was achieved using the promoter, signal sequence and terminator regions of phospholipase
D from Streptoverticillium cinnamoneum. The transformant constitutively expressed a high specific activity of SMase extracellularly during batch culture. Maximum
SMase activity (555 ± 114 U/mg protein) was with 1.75 M MgCl2 which was about 50-fold more than that with 10 mM MgCl2. 相似文献
14.
Marta Herreros-Villanueva Maximiliano Rodrigo Manuel Claver Pilar Muñiz Enrique Lastra Carlos García-Girón Maria Jesus Coma del Corral 《Molecular biology reports》2011,38(2):1315-1320
To evaluate the KRAS, BRAF, EGFR, and HER2 gene status in colorectal cancer by novel techniques and evaluate whether anti-HER2 therapies could be offered in the treatment
of these patients. There are conflicting data on the prevalence of BRAF mutations and EGFR and HER2 gene amplification in colorectal KRAS wild type patients. In our study we tried to evaluate these expressions and their relationship to future treatment assays.
Clinical–pathological data and paraffin-embedded specimens were collected from 186 patients who underwent colorectal resections
at General Yagüe Hospital in Burgos, Spain. KRAS and BRAF status was analyzed by real-time PCR in all patients. EGFR and HER2/NEU gene amplification was detected using fluorescent in situ hybridisation technique (FISH) in 38 KRAS and BRAF wild type patients. KRAS mutations were present in 48% of the colorectal cancer patients. BRAF mutations were present in 6.25% of the KRAS wild type patients. EGFR and HER2 gene amplification was observed in 5.3% and 26.3%, respectively, of KRAS and BRAF wild type colorectal cancer patients. HER2, but not EGFR gene amplification, was frequently observed in KRAS and BRAF wild type colorectal cancer patients. These data indicate that HER2 amplification could be one of the genes to be considered in the therapeutic management of colorectal cancer. 相似文献
15.
Kameshnee Naidoo Manimaran Ayyachamy Kugen Permaul Suren Singh 《Bioprocess and biosystems engineering》2009,32(5):689-695
Xanthomonas campestris pv phaseoli produced an extracellular endoinulinase (9.24 ± 0.03 U mL−1) in an optimized medium comprising of 3% sucrose and 2.5% tryptone. X. campestris pv. phaseoli was further subjected to ethylmethanesulfonate mutagenesis and the resulting mutant, X. campestris pv. phaseoli KM 24 demonstrated inulinase production of 22.09 ± 0.03 U mL−1 after 18 h, which was 2.4-fold higher than that of the wild type. Inulinase production by this mutant was scaled up using
sucrose as a carbon source in a 5-L fermenter yielding maximum volumetric (21,865 U L−1 h−1) and specific (119,025 U g−1 h−1) productivities of inulinase after 18 h with an inulinase/invertase ratio of 2.6. A maximum FOS production of 11.9 g L−1 h−1 and specific productivity of 72 g g−1 h−1 FOS from inulin were observed in a fermenter, when the mutant was grown on medium containing 3% inulin and 2.5% tryptone.
The detection of mono- and oligosaccharides in inulin hydrolysates by TLC analysis indicated the presence of an endoinulinase.
This mutant has potential for large-scale production of inulinase and fructooligosaccharides. 相似文献
16.
Inger-Marie E. Vilcins Julie M. Old Elizabeth Deane 《Experimental & applied acarology》2009,49(3):229-242
Three Australian native animal species yielded 60 samples composed of three indigenous ticks. Hosts included twelve koalas,
two echidnas and one wombat from Victoria, and ticks were of the species Ixodes tasmani (n = 42), Bothriocroton concolor (n = 8) and B. auruginans (n = 10), respectively. PCR screening and sequencing detected a species of Coxiella, sharing closest sequence identity to C. burnetii (>98%), in all B. auruginans, as well as a species of Rickettsia, matching closest to R. massiliae, in 70% of the same samples. A genotype sharing closest similarity to Rickettsia bellii (>99%) was identified in three female B. concolor collected from one of the echidnas. Three samples of I. tasmani, taken from three koalas, yielded different genotypes of Rickettsiella. These results represent the first detection of the three genera in each tick species and identify a high level of previously
undetected bacterial diversity in Australian ticks. 相似文献
17.
Jerzy Woyke Jerzy Wilde Maria Wilde Venkataramegowda Sivaram Cleofas Cervancia Narajanappa Nagaraja Muniswamyreddy Reddy 《Journal of Insect Behavior》2008,21(6):481-494
Defense behavior of three, free living giant (Megapis) honey bee subspecies, Apis laboriosa, A. dorsata dorsata and A. dorsata breviligula, was compared. Disturbed worker bees responded with characteristic dorso-ventral defense body twisting (DBT). Workers of
A. laboriosa twisted the thorax by 55°, and the two other A. dorsata subspecies by about 10° more. A. laboriosa workers raised the tip of the abdomen by 90° and workers of the two other bee subspecies by about 20° higher. Differences
in those traits were highly significant between A. laboriosa and both A. dorsata subspecies, but were not significant between those two subspecies. The whole cycle of DBT was the most vigorous in A. d. breviligula (0.11 s), and it was twice as vigorous as in A. d. dorsata (0.26 s) and trice as in A. laboriosa (0.32 s). A. laboriosa twisted the body together with wings folded over the abdomen, while the two A. dorsata subspecies raised the abdomen between spread wings. This supports the opinion to treat A. laboriosa as a separate species.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
18.
To relate the pharmacokinetics of orally administered lansoprazole in healthy adult Jordanian men with CYP2C19 polymorphisms
and to determine the percentage of CYP2C19 polymorphism in Jordanian population and the allelic frequency of CYP2C19*2 and CYP2C19*3. A total of 78 healthy Jordanian volunteers were included in this study from three different bioequivalence studies, one
of these studies which included 26 volunteers was done on lansoprazole. Genotyping for CYP2C19*1, CYP2C19*2, CYP2C19*3 was done for all 78 volunteers, the data of genotyping of all subjects used for screening the frequency of different genotypes
and the allelic frequency of different polymorphisms in healthy Jordanian men, the pharmacokinetics and genotyping data for
the study of lansoprazole was matched and compared to investigate presence of statistical differences in pharmacokinetic parameters.
In Jordanian subjects, the allele frequencies of the CYP2C19*2 and CYP2C19*3 mutation were 0.16 and 0, respectively. The concentration–time curves in the two groups [homozygote extensive metabolizer
(homEM, n = 19) and heterozygote extensive metabolizer (homEM, n = 7)] groups were fitted to a non-compartment model. In the homEM and in the hetEM groups, the main kinetic parameters were
as follows: Tmax (2.1875 ± 0.777) and (2.54 ± 1.87) h, Cmax (697.875 ± 335) and (833.58 ± 436.26) mg/l, t1/2 (1.3 ± 0.43) and (2.38 ± 1.64) h, AUC(0→∞) were (1,684.9 ± 888) and (3,609.8 ± 318) mg h l−1, respectively. The Jordanian population showed similarities in CYP2C19 allele and genotype distribution pattern with Caucasians and Africans. CYP2C19 allele and poor metabolizer (PM) genotype frequencies in the Jordanian population are distinct from populations’ from East
Asia such as Japanese and Koreans. Although lower pharmacokinetic parameters were found in homEM compared to hetEM but there
was no significant difference between the two groups (P < 0.05). 相似文献
19.
Aporn Bualuang Kanteera Soontharapirakkul Aran Incharoensakdi 《Journal of applied phycology》2010,22(2):123-129
The activity of Na+/H+ exchanger to remove toxic Na+ is important for growth of organisms under high salinity. In this study, the halotolerant cyanobacterium Aphanothece halophytica was shown to possess Na+/H+ exchange activity since exogenously added Na+ could dissipate a pre-formed pH gradient, and decrease extracellular pH. Kinetic analysis yielded apparent K
m (Na+) and V
max of 20.7 ± 3.1 mM and 3,333 ± 370 nmol H+ min−1 mg−1, respectively. For cells grown under salt-stress condition, the apparent K
m (Na+) and V
max was 18.3 ± 3.5 mM and 3,703 ± 350 nmol H+ min−1 mg−1, respectively. Three cations with decreasing efficiency namely Li+, Ca2+, and K+ were also able to dissipate pH gradient. Only marginal exchange activity was observed for Mg2+. The exchange activity was strongly inhibited by Na+-gradient dissipators, monensin, and sodium ionophore as well as by CCCP, a protonophore. A. halophytica showed high Na+/H+ exchange activity at neutral and alkaline pH up to pH 10. Cells grown at pH 7.6 under high salinity exhibited higher Na+/H+ exchange activity than those grown under low salinity during 15 days of growth suggesting a role of Na+/H+ exchanger for salt tolerance in A. halophytica. Cells grown at alkaline pH of 9.0 also exhibited a progressive increase of Na+/H+ exchange activity during 15 days of growth. 相似文献
20.
To screen stimulators from Chinese medicinal insects for mycelial growth and polysaccharides production of Ganoderma lucidum, G. lucidum was inoculated into the media with and without supplementation of medicinal insect extracts. The ethyl acetate extract of
Eupolyphaga sinensis at 55 mg l−1 lead to significant increase in both biomass and intracellular polysaccharides (IPS) concentration from 8.53 ± 0.41 to 14.16 ± 0.43
and 1.28 ± 0.09 to 2.13 ± 0.11 g l−1, respectively. In addition, the ethyl acetate extract of Catharsius molossus at 55 mg l−1 significantly enhanced extracellular polysaccharides (EPS) production; the EPS yield increased from 350.9 ± 14.1 to 475.1 ± 15.3 mg
l−1. There were no new components in the two types of polysaccharides obtained by the addition of the insect extracts. 相似文献