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1.
Francisco Gasulla Pedro Gómez de Nova Alberto Esteban-Carrasco José M. Zapata Eva Barreno Alfredo Guéra 《Planta》2009,231(1):195-208
The mechanisms involved in desiccation tolerance of lichens and their photobionts are still poorly understood. To better understand
these mechanisms we have studied dehydration rate and desiccation time in Trebouxia, the most abundant chlorophytic photobiont in lichen. Our findings indicate that the drying rate has a profound effect on
the recovery of photosynthetic activity of algae after rehydration, greater than the effects of desiccation duration. The
basal fluorescence (F′o) values in desiccated algae were significantly higher after rapid dehydration, than after slow dehydration, suggesting higher
levels of light energy dissipation in slow-dried algae. Higher values of PSII electron transport were recovered after rehydration
of slow-dried Trebouxia erici compared to rapid-dried algae. The main component of non-photochemical quenching after slow dehydration was energy dependent
(q
E), whereas after fast dehydration it was photoinhibition (q
I). Although q
E seems to play a role during desiccation recovery, no significant variations were detected in the xanthophyll cycle components.
Desiccation did not affect PSI functionality. Classical antioxidant activities like superoxide dismutase or peroxidase decreased
during desiccation and early recovery. Dehydrins were detected in the lichen-forming algae T. erici and were constitutively expressed. There is probably a minimal period required to develop strategies which will facilitate
transition to the desiccated state in this algae. In this process, the xanthophyll cycle and classical antioxidant mechanisms
play a very limited role, if any. However, our results indicate that there is an alternative mechanism of light energy dissipation
during desiccation, where activation is dependent on a sufficiently slow dehydration rate. 相似文献
2.
There are three most important bacterial causative agents of serious infections that could be misused for warfare purposes:
Bacillus anthracis (the causative agent of anthrax) is the most frequently mentioned one; however, Fracisella tularensis (causing tularemia) and Yersinia pestis (the causative agent of plague) are further bacterial agents enlisted by Centers for Disease Control and Prevention into the category A of potential biological weapons. This review intends to summarize basic information about these bacterial
agents. Military aspects of their pathogenesis and the detection techniques suitable for field use are discussed. 相似文献
3.
N. Yu. Markelova 《Microbiology》2010,79(6):777-779
Interaction of Bdellovibrio bacteriovorus 100NCJB with bacteria Campylobacter jejuni (strains 1, 2, 3, 4, and 5) and Helicobacter pylori, strain TX30a, was confirmed. The results indicate that lytic activity of bdellovibrios both in liquid media and cells attached
to a surface was observed. The potential use of the antimicrobial activity of predatory bacteria for environmental bioprotection
and public health is discussed. 相似文献
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The life cycle and developmental stages of Aylax hypecoi (Trotter, 1913, Hymenoptera: Cynipidae: Aylacini) were studied in detail. Aylax hypecoi is known to induce galls in fruits of two Hypecoum species — H. imberbe and H. geslini (Papaveraceae) and the larva develops in host plant fruits. The morphology and development of egg, larva and pupa were investigated, which
has previously not been done. The shape and size of terminal-instar larvae and associated galls are sex-specific. Overwintering
stage, adult emergence and flying periods, and egg productivity were studied also. 相似文献
6.
Following a re-examination of the material treated under Barleria brevispina (Fiori) Hedrén in the recent Flora of Somalia account of the Acanthaceae, it is concluded that two distinct species are involved and Barleria compacta Malombe & I. Darbysh. is described here from north-eastern Somalia. Its affinities and conservation status are discussed. 相似文献
7.
Hiroyoshi Kubo 《Mycoscience》2009,50(5):400-406
Pilobolus crystallinus shows unique photoresponses at various growing stages. cDNAs for putative photoreceptors were cloned from this fungus. Three
genes named pcmada1, pcmada2, and pcmada3 were identified from the PCR fragments, and amplified with degenerated primers for the LOV domain, which is conserved in
many blue-light receptors. Deduced amino acid sequences for PCMADA1, PCMADA2, and PCMADA3 had one light-oxygen-voltage (LOV)-sensing
and two PER-ARNT-SIM (PAS) domains. A zinc finger DNA-binding motif was conserved in the C-terminals of PCMADA1 and PCMADA3.
However, PCMADA2 lacked the zinc finger motif. Expression of pcmada1 was suppressed by blue light whereas that of pcmada3 was promoted by blue-light irradiation. 相似文献
8.
The intron sequence of chloroplast rpS16 and the secondary structure of its pre-mRNA were characterized for the first time in 26 Allium sativum accessions of different ecologo-geographical origins and seven related Allium species. The boundaries and main stem-loop consensus sequences were identified for all six domains of the intron. Polymorphism
was estimated for the total intron and its regions. The structural regions of the rpS16 intron proved to be heterogeneous for mutation rate and spectrum. Mutations were most abundant in domains II and IV, and
transition predominated in domains I, III, V, and VI. In addition to structural elements and motifs typical for group IIB
introns, several Allium-specific micro- and macrostructural mutations were revealed. A 290-bp deletion involving domains III and IV and part of domain
V was observed in A. altaicum, A. fistulosum, and A. schoenoprasum. Several indels and nucleotide substitutions were found to cause a deviation of the pre-mRNA secondary structure from the
consensus model of group II introns. 相似文献
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I. Rosario G. Soro S. Déniz O. Ferrer F. Acosta D. Padilla B. Acosta 《Mycopathologia》2010,169(4):315-319
Columba livia is an important reservoir and carrier of Cryptococcus neoformans, Cryptococcus uniguttulatus, Cryptococcus laurentii and Cryptococcus albidus. Upper digestive tract of this species is also known as a habitat for Cryptococcus neoformans. Given the increasing clinical interest of this microorganism, 331 swabs from crop and 174 dropping samples from pigeon lofts
in Grand Canary Island have been studied. The obtained results show an extensive presence samples 81 positive (24.47%) of
Cryptococcus spp. in analysed crops: 32 (9.66%) for C. neoformans, 24 (7.2%) for C. uniguttulatus, 23 (6.9%) for C. albidus and 2 (0.6%) for C. laurentii. In the same way, Cryptococcus spp was also isolated in 82 (47.13%), dropping samples: C. neoformans in 59 (33.9%), C. uniguttulatus, in 9 (5.17%), C. laurentii in 8 (4.59%) and C. albidus in 6 (3.44%) of the investigated samples, respectively. The cryptococcosis produced by species of cryptococci other than C. neoformans has become more important during the last decade, supporting the study on the role of pigeon in the epidemiology of this
disease. 相似文献
14.
Gaye Öngen Gaye Güngör Bahar Kanberoglu 《World journal of microbiology & biotechnology》2007,23(4):519-524
Aspergillus section Nigri strains Aspergillus aculeatus Ege-K 258, A.
foeditus var. pallidus Ege-K156, A. niger Ege-K 4 and A. tubingensis Ege-K 265 were used to treat olive mill wastewater (OMW) in an investigation aimed at exploring their dephenolisation and
decolourisation ability and, consequently, the economic feasibility of using any or all of these strains in a pre-treatment
step in the processing of OMW. Of these strains A. tubingensis Ege-K 265 resulted in an 80% decolourisation of twofold-diluted OMW and a 30% decolourisation of undiluted OMW; in addition,
it was able to remove approximately 30% of all phenolic compounds in both twofold-diluted and undiluted OMW. We conclude that
A. tubingensis Ege-K 265 could be effectively used in the pre-treatment step of a combined aerobic-anaerobic process to solve the environmental
problems caused by OMW in Mediterranean countries. 相似文献
15.
Nanobodies (or VHHs) are single-domain antigen-binding fragments derived from Camelid heavy chain-only antibodies. Their small size, monomeric behaviour, high stability and solubility, and ability to bind epitopes
not accessible to conventional antibodies make them especially suitable for many therapeutic and biotechnological applications.
Here we describe high-level expression, in Nicotiana benthamiana, of three versions of an anti-hen egg white lysozyme (HEWL) nanobody which include the original VHH from an immunized library
(cAbLys3), a codon-optimized derivative, and a codon-optimized hybrid nanobody comprising the CDRs of cAbLys3 grafted onto
an alternative ‘universal’ nanobody framework. His6- and StrepII-tagged derivatives of each nanobody were targeted for accumulation
in the cytoplasm, chloroplast and apoplast using different pre-sequences. When targeted to the apoplast, intact functional
nanobodies accumulated at an exceptionally high level (up to 30% total leaf protein), demonstrating the great potential of
plants as a nanobody production system. 相似文献
16.
Haoran An Hui Zhou Ying Huang Guohong Wang Chunguang Luan Jing Mou Yunbo Luo Yanling Hao 《Molecular biotechnology》2010,45(2):155-160
Lactic acid bacteria (LAB) are generally sensitive to hydrogen peroxide (H2O2), Lactobacillus sakei YSI8 is one of the very few LAB strains able to degrade H2O2 through the action of a heme-dependent catalase. Lactobacillus rhamnosus strains are very important probiotic starter cultures in meat product fermentation, but they are deficient in catalase. In
this study, the effect of heterologous expression of L. sakei catalase gene katA in L. rhamnosus on its oxidative stress resistance was tested. The recombinant L. rhamnosus AS 1.2466 was able to decompose H2O2 and the catalase activity reached 2.85 μmol H2O2/min/108 c.f.u. Furthermore, the expression of the katA gene in L. rhamnosus conferred enhanced oxidative resistance on the host. The survival ratios after short-term H2O2 challenge were increased 600 and 104-fold at exponential and stationary phase, respectively. Further, viable cells were 100-fold higher in long-term aerated cultures.
Simulation experiment demonstrated that both growth and catalase activity of recombinant L. rhamnosus displayed high stability under environmental conditions similar to those encountered during sausage fermentation. 相似文献
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Khomaini Hasan Wangsa Tirta Ismaya Idar Kardi Yandi Andiyana Susanti Kusumawidjaya Safri Ishmayana Toto Subroto Soetijoso Soemitro 《Biologia》2008,63(6):1044-1050
α-Amylase from Saccharomycopsis fibuligera R-64 was successfully purified by butyl Toyopearl hydrophobic interaction chromatography, followed by Sephadex G-25 size
exclusion and DEAE Toyopearl anion exchange chromatography. The enzyme has a molecular mass of 54 kDa, as judged by SDS PAGE
analysis. Upon tryptic digestion, two major fragments with relative molecular masses of 39 kDa and 10 kDa, which resemble
the A/B and C-terminal domains in the homologous Taka-amylase, were obtained and were successfully separated with the Sephadex
G-50 size exclusion column. The 39-kDa fragment demonstrated a similar amylolytic activity to that of the undigested enzyme.
However, it was found that the K
m value of the 39-kDa fragment was about two-times higher than that of the undigested enzyme. Moreover, thermostability studies
showed a lower half-life time for the 39-kDa fragment. These findings suggest that the 39-kDa fragment is the catalytic domain,
while the 10-kDa fragment is the C-terminal one, which plays a role in thermostability and starch binding. Although the undigested
enzyme is able to act on raw starches at room temperature, with maize starches as the best substrate, neither the undigested
enzyme nor the fragments adsorb the tested raw starches. These results propose Saccharomycopsis fibuligera α-amylase as a raw starch-digesting but not adsorbing amylase, with a similar domain organization to that of Taka-amylase A. 相似文献
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