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11.
Efficient secretory expression of functional barley limit dextrinase inhibitor by high cell-density fermentation of Pichia pastoris 总被引:1,自引:0,他引:1
Jensen JM Vester-Christensen MB Møller MS Bønsager BC Christensen HE Hachem MA Svensson B 《Protein expression and purification》2011,79(2):217-222
The limit dextrinase inhibitor (LDI) from barley seeds acts specifically on limit dextrinase (LD), an endogenous starch debranching enzyme. LDI is a 14 kDa hydrophobic protein containing four disulfide bonds and one unpaired thiol group previously found to be either glutathionylated or cysteinylated. It is a member of the so-called CM-protein family that includes α-amylase and serine protease inhibitors, which have been extremely challenging to produce recombinantly in functional form and in good yields. Here, LDI is produced in very high yields by secretory expression by Pichia pastoris applying high cell-density fermentation in a 5L fed-batch bioreactor. Thus about 200mg of LDI, which showed twofold higher inhibitory activity towards LD than LDI from barley seeds, was purified from 1L of culture supernatant by His-tag affinity chromatography and gel filtration. Electrospray ionization mass spectrometry verified the identity of the produced glutathionylated LDI-His(6). At a 1:1M ratio the recombinant LDI completely inhibited hydrolysis of pullulan catalyzed by 5-10 nM LD. LDI retained stability in the pH 2-12 range and at pH 6.5 displayed a half-life of 53 and 33 min at 90 and 93°C, respectively. The efficient heterologous production of LDI suggests secretory expression by P. pastoris to be a promising strategy to obtain other recombinant CM-proteins. 相似文献
12.
TT Nielsen S Mardosiene A Løkkegaard J Stokholm S Ehrenfels S Bech L Friberg JK Nielsen JE Nielsen 《BMC neurology》2012,12(1):73
ABSTRACT: BACKGROUND: The autosomal dominant spinocerebellar ataxias (SCAs) confine a group of rare and heterogeneous disorders, which present with progressive ataxia and numerous other features e.g. peripheral neuropathy, macular degeneration and cognitive impairment, and a subset of these disorders is caused by CAG-repeat expansions in their respective genes. The diagnosing of the SCAs is often difficult due to the phenotypic overlap among several of the subtypes and with other neurodegenerative disorders e.g. Huntington's disease, CASE PRESENTATION: We report a family in which the proband had rapidly progressing cognitive decline and only subtle cerebellar symptoms from age 42. Sequencing of the TATA-box binding protein gene revealed a modest elongation of the CAG/CAA-repeat of only two repeats above the non-pathogenic threshold of 41, confirming a diagnosis of SCA17. Normally, repeats within this range show reduced penetrance and result in a milder disease course with slower progression and later age of onset. Thus, this case presented with an unusual phenotype. CONCLUSIONS: The current case highlights the diagnostic challenge of neurodegenerative disorders and the need for a thorough clinical and paraclinical examination of patients presenting with rapid cognitive decline to make a precise diagnosis on which further genetic counseling and initiation of treatment modalities can be based. 相似文献
13.
K. Bech 《Journal of Phytopathology》1994,141(3):285-292
Meristems were excised from young and 8-month-old Kalanchoë blossfeldiana naturally-infected with Erwinia chrysanthemi (Echr). From heavily infected plants the bacteria were identified in meristems from the very top of the plant as well as from meristems situated lower on the plant. In other naturally-infected plants Echr was only found at the stem base, depending on how advanced (old) the infection was. Repetition of identification on meristem samples stored in the refrigerator for1 week revealed more positive samples than in the first test. Infection trials showed a quick spread of bacteria from stem base to apex via xylem vessels in some of the inoculated plants. Spread of Echr via capillary mats from inoculated to non-inoculated Kalanchoë plants were found after 5.5 months growth on the capillary mat. The time lapse before transmission may vary with the seasons of the year. 相似文献
14.
Influence of body composition on the metabolic rate of nestling European shags (Phalacrocorax aristotelis) 总被引:2,自引:0,他引:2
C. Bech J. E. Østnes 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1999,169(4-5):263-270
During the early development of avian nestlings, their mass-specific resting metabolic rate (RMR) changes in a biphasic pattern
with the peak value often being much higher than that expected for an adult bird of similar body mass. In the present study
we examined the possible influence of variations in the size of internal organs in “setting” the high RMR and peak metabolic
rate (PMR) during development in a large altricial species, the European shag (Phalacrocorax aristotelis). Thermoneutral RMR and cold-exposure induced PMR were measured in nestlings 15 days old, the age at which the highest RMR
occurred during development. Body mass averaged 414 g. Mean values of RMR and PMR were 5.75 W and 9.08 W, respectively; the
RMR value corresponds to approximately 250% of the expected value for an adult non-passerine bird of similar body mass. The
masses of all the organs measured (breast and leg muscles, heart, liver, intestine, and kidney) varied isometrically with
total body mass. However, large chicks had a significantly lower fractional water content than small chicks, suggesting that
the former had achieved a higher level of functional maturity. In contrast to what has been suggested for adult birds in general,
the heart and kidney masses of shag nestlings were not significantly correlated with the metabolic rates. The intestine length,
in contrast, was highly and positively correlated with both the RMR and the PMR, i.e. intestine length was a better predictor
of RMR and PMR than was total body mass. In addition, liver mass was positively correlated with RMR. The results of the present
study suggest that the liver in particular may play a key role in establishing the high, mass-specific RMR which is attained
during development in bird chicks. Our results also support previous suggestions that early in their development, altricial
chicks mainly allocate energy to the growth of `energy-processing' organs (such as the intestine and liver) rather than to
`energy-consuming' organs.
Accepted: 3 March 1999 相似文献
15.
Consequences of Swidden Transitions for Crop and Fallow Biodiversity in Southeast Asia 总被引:6,自引:4,他引:2
Kanok Rerkasem Deborah Lawrence Christine Padoch Dietrich Schmidt-Vogt Alan D. Ziegler Thilde Bech Bruun 《Human ecology: an interdisciplinary journal》2009,37(3):347-360
Swidden agriculture, once the dominant form of land use throughout the uplands and much of the lowlands of Southeast Asia,
is being replaced by other land uses. While change and adaptation are inherent to swiddening, the current rapid and widespread
transitions are unprecedented. In this paper we review some recent findings on changes in biodiversity, especially plant diversity
at various scales, as swidden farming is replaced by other land uses. We focus particularly on two areas of Southeast Asia:
northern Thailand and West Kalimantan. We examine actual and potential changes in the diversity of crops that characterize
regional swidden systems, as well as that of the spontaneously occurring plants that appear in swidden fields and fallows.
Severe declines in plant diversity have been observed in most areas and at most spatial scales when swidden is replaced by
permanent land use systems. However, shifts away from swidden agriculture do not invariably result in drastic declines or
losses of biological diversity, but may maintain or even enhance it, particularly at finer spatial scales. We suggest that
further research is necessary to understand the effects of swidden transitions on biodiversity. 相似文献
16.
Expected consequences of global warming include habitat reduction in many cool climate species. Rock ptarmigan is a Holarctic grouse that inhabits arctic and alpine tundra. In Europe, the Pyrenean ptarmigan inhabits the southern edge of the species' range and since the last glacial maximum its habitat has been severely fragmented and is restricted to high-alpine zones or 'sky islands'. A recent study of rock ptarmigan population genetic in Europe found that the Pyrenean ptarmigan had very low genetic diversity compared with that found in the Alps and Scandinavia. Habitat fragmentation and reduced genetic diversity raises concerns about the viability of ptarmigan populations in the Pyrenees. However, information on population structuring and gene flow across the Pyrenees, which is essential for designing a sound management plan, is absent. In this study, we use seven microsatellites and mitochondrial control region sequences to investigate genetic variation and differentiation among five localities across the Pyrenees. Our analyses reveal the presence of genetic differentiation among all five localities and a significant isolation-by-distance effect that is likely the result of short dispersal distances and high natal and breeding philopatry of Pyrenean ptarmigan coupled with severe habitat fragmentation. Furthermore, analysis of molecular variance, principal component analysis and Bayesian analysis of genetic structuring identified the greatest amount of differentiation between the eastern and main parts of the Pyrenean chain separated by the Sègre Valley. Our data also show that the Canigou massif may host an isolated population and requires special conservation attention. We propose a management plan which includes the translocation of birds. If a sky island structure affects genetic divergence in rock ptarmigan, it may also affect the genetic structure of other sky island species having low dispersal abilities. 相似文献
17.
Litrico I Bech N Flajoulot S Cadier D Talon C Gibelin C Barre P 《Molecular ecology resources》2009,9(1):159-164
We report results of cross-species amplification in Dactylis glomerata and Lolium perenne of 12 simple sequence repeats (SSRs) isolated from Lolium multiflorum×Festuca glaucescens, 42 SSRs from Festuca arundinacea and two sequence tagged sites from Oryza sativa. We compared the transferability and diversity between D. glomerata and L. perenne, which are important forage crops. While Nei's gene diversity values were equivalent in both species (from 0.14 to 0.92), the mean number of allele per locus was more important in D. glomerata than in L. perenne (5.45 vs. 4.50). These markers will be used for analysing population structure in grassland populations under agronomic practices. 相似文献
18.
Lene Wulff Krogsgaard Irene Petersen Oleguer Plana-Ripoll Bodil Hammer Bech Tina Hovgaard Lützen Reimar Wernich Thomsen Dorte Rytter 《PLoS medicine》2021,18(9)
BackgroundPublic trust in the human papilloma virus (HPV) vaccination programme has been challenged by reports of potential severe adverse effects. The reported adverse symptoms were heterogeneous and overlapping with those characterised as chronic fatigue syndrome (CFS) and have been described as CFS-like symptoms. Evidence suggests that CFS is often precipitated by an infection. The aim of the study was to examine if an infection in temporal proximity to HPV vaccination is a risk factor for suspected adverse effects following HPV vaccination.Methods and findingsThe study was a nationwide register-based cohort study and case-crossover analysis. The study population consisted of all HPV vaccinated females living in Denmark, born between 1974 and 2006, and vaccinated between January 1, 2006 and December 31, 2017. The exposure was any infection in the period ± 1 month around time of first HPV vaccination and was defined as (1) hospital-treated infection; (2) redemption of anti-infective medication; or (3) having a rapid streptococcal test done at the general practitioner. The outcome was referral to a specialised hospital setting (5 national HPV centres opened June 1, 2015) due to suspected adverse effects following HPV vaccination. Multivariable logistic regression was used to estimate the association between infection and later HPV centre referral. The participants were 600,400 HPV-vaccinated females aged 11 to 44 years. Of these, 48,361 (9.7%) females had a hospital-treated infection, redeemed anti-infective medication, or had a rapid streptococcal test ± 1 month around time of first HPV vaccination. A total of 1,755 (0.3%) females were referred to an HPV centre. Having a hospital-treated infection in temporal proximity to vaccination was associated with significantly elevated risk of later referral to an HPV centre (odds ratio (OR) 2.75, 95% confidence interval (CI) 1.72 to 4.40; P < 0.001). Increased risk was also observed among females who redeemed anti-infective medication (OR 1.56, 95% CI 1.33 to 1.83; P < 0.001) or had a rapid streptococcal test (OR 1.45, 95% CI 1.10 to 1.93; P = 0.010). Results from a case-crossover analysis, which was performed to adjust for potential unmeasured confounding, supported the findings. A key limitation of the study is that the HPV centres did not open until June 1, 2015, which may have led to an underestimation of the risk of suspected adverse effects, but stratified analyses by year of vaccination yielded similar results.ConclusionsTreated infection in temporal proximity to HPV vaccination is associated with increased risk for later referral with suspected adverse vaccine effects. Thus, the infection could potentially be a trigger of the CFS-like symptoms in a subset of the referred females. To our knowledge, the study is the first to investigate the role of infection in the development of suspected adverse effects after HPV vaccination and replication of these findings are needed in other studies.Lene Wulff Krogsgaard and co-workers study temporal associations between infections and HPV vaccination. 相似文献
19.
Jiong Li Mogens Vestergaard Sven Cnattingius Mika Gissler Bodil Hammer Bech Carsten Obel J?rn Olsen 《PLoS medicine》2014,11(7)