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排序方式: 共有133条查询结果,搜索用时 265 毫秒
101.
The Baja California Peninsula and surrounding landmasses harbor an abundant flora in an otherwise harsh and arid environment. Of the many plant groups native to this peninsular and insular region, passionflowers (Passiflora, Passifloraceae) are represented by several conspicuous taxa that all belong to a single lineage, section Dysosmia. Basic questions remain regarding this group, particularly the taxonomic status among the Passiflora arida complex. Therefore, we investigated the claims of endemism, habitat characteristics, and taxon boundaries with in section Dysosmia in the Baja California region using extensive sampling of herbarium specimens and iNaturalist observations. We confirmed that only one of the native Passiflora taxa (P. fruticosa) was endemic to the Baja California Peninsula, with an additional taxon (P. palmeri) considered near‐endemic. Environmental data revealed significant distinctions between the habitats of many of the native taxa as well as within the P. arida complex, especially with respect to precipitation and temperature tolerances. Geometric morphometric analyses of leaf shape were largely not successful at separating taxa, indicating leaf shape may not be a good indicator of taxon identity in this particular group. Based on ecological differences and discrete macro‐ and micromorphological features, a varietal name is here synonymized and a new combination is proposed: Passiflora pentaschista. 相似文献
102.
The segregation of laboratory maintained male and larval Myrmecia gulosa from workers resulted in increased levels of culturable microbiota. After 29 days, microbial levels recovered from segregated males and larvae were 27 and 126 times greater than from males and larvae not segregated from workers. These findings are consistent with the hypothesis that metapleural gland secretions, absent in larvae and males, are transferred from workers to larvae, and males contribute to the inhibition of cuticular microbiota. 相似文献
103.
Laura McAuliffe Colin P Churchward Joanna R Lawes Guido Loria Roger D Ayling Robin AJ Nicholas 《BMC microbiology》2008,8(1):193
Background
Mycoplasma agalactiae is the main cause of contagious agalactia, a serious disease of sheep and goats, which has major clinical and economic impacts. Previous studies of M. agalactiae have shown it to be unusually homogeneous and there are currently no available epidemiological techniques which enable a high degree of strain differentiation. 相似文献104.
Mark F Brady Jorge Coronel Robert H Gilman David AJ Moore 《Journal of visualized experiments : JoVE》2008,(18)
Patients with active pulmonary tuberculosis (TB) infect 10-15 other persons per year, making diagnosing active TB essential to both curing the patient and preventing new infections. Furthermore, the emergence of multidrug resistant tuberculosis (MDRTB) means that detection of drug resistance is necessary for stopping the spread of drug-resistant strains. The microscopic-observation drug-susceptibility (MODS) assay is a low-cost, low-tech tool for high-performance detection of TB and MDRTB. The MODS assay is based on three principles: 1) mycobacterium tuberculosis (MTB) grows faster in liquid media than on solid media 2) microscopic MTB growth can be detected earlier in liquid media than waiting for the macroscopic appearance of colonies on solid media, and that growth is characteristic of MTB, allowing it to be distinguished from atypical mycobacteria or fungal or bacterial contamination 3) the drugs isoniazid and rifampicin can be incorporated into the MODS assay to allow for simultaneous direct detection of MDRTB, obviating the need for subculture to perform an indirect drug susceptibility test. Competing current diagnostics are hampered by low sensitivity with sputum smear, long delays until diagnosis with solid media culture, prohibitively high cost with existing liquid media culture methods, and the need to do subculture for indirect drug susceptibility testing to detect MDRTB. In contrast, the non-proprietary MODS method has a high sensitivity for TB and MDRTB, is a relatively rapid culture method, provides simultaneous drug susceptibility testing for MDRTB, and is accessible to resource-limited settings at just under $3 for testing for TB and MDRTB.Download video file.(243M, mp4) 相似文献
105.
Fourteen native strains of Trichoderma spp. from wildand agricultural pathosystems in the state of Yucatan, Mexico, with growth-promoting ability of Capsicum chinense Jacq. seedlings were evaluated and antagonistic effect of their filtrate against second-stage juveniles (J2) of Meloidogyne incognita. The strains Th05-02 and Th27-08 showed the best significant effects on plant hight variable increments 55.57 and 47.62%, theTh07-04 with 29.48% more root length, theTh02-01 and Th07-04 isolates increased from 48.71 to 84.61% in volume radical and 53.40% of total dry biomass. Statistical analysis (p≤0.001) of Th43 and Th43-13-14 filtrates caused 100% mortality at 24 and 48h. In the test of reversibility to 24 h after replacing the filtrates Th43-13, Th43-14, TH09-06 and TH20-07 by sterile distilled water, the J2 did not recover their viability, so they were considered as the best potential strains of Trichoderma spp. with antagonistic capacity in J2 of M.incognita. 相似文献
106.
Jurriaan J H?lzenspies Willem Stoorvogel Ben Colenbrander Bernard AJ Roelen Dagmar R Gutknecht Theo van Haeften 《BMC developmental biology》2009,9(1):8
Background
Mammalian oocytes acquire competence to be fertilized during meiotic maturation. The protein kinase CDC2 plays a pivotal role in several key maturation events, in part through controlled changes in CDC2 localization. Although CDC2 is involved in initiation of maturation, a detailed analysis of CDC2 localization at the onset of maturation is lacking. In this study, the subcellular distribution of CDC2 and its regulatory proteins cyclin B and SPDY in combination with several organelle markers at the onset of pig oocyte maturation has been investigated. 相似文献107.
Gwendoline Kint Kathleen AJ Sonck Geert Schoofs David De Coster Jos Vanderleyden Sigrid CJ De Keersmaecker 《BMC microbiology》2009,9(1):198
Background
Quorum sensing is a term describing a bacterial communication system mediated by the production and recognition of small signaling molecules. The LuxS enzyme, catalyzing the synthesis of AI-2, is conserved in a wide diversity of bacteria. AI-2 has therefore been suggested as an interspecies quorum sensing signal. To investigate the role of endogenous AI-2 in protein expression of the Gram-negative pathogen Salmonella enterica serovar Typhimurium (S. Typhimurium), we performed a 2D-DIGE proteomics experiment comparing total protein extract of wildtype S. Typhimurium with that of a luxS mutant, unable to produce AI-2. 相似文献108.
William J Holmes Richard AJ Darby Martin DB Wilks Rodney Smith Roslyn M Bill 《Microbial cell factories》2009,8(1):35-14
Background
The optimisation and scale-up of process conditions leading to high yields of recombinant proteins is an enduring bottleneck in the post-genomic sciences. Typical experiments rely on varying selected parameters through repeated rounds of trial-and-error optimisation. To rationalise this, several groups have recently adopted the 'design of experiments' (DoE) approach frequently used in industry. Studies have focused on parameters such as medium composition, nutrient feed rates and induction of expression in shake flasks or bioreactors, as well as oxygen transfer rates in micro-well plates. In this study we wanted to generate a predictive model that described small-scale screens and to test its scalability to bioreactors. 相似文献109.
van de Loo FA 《Arthritis research & therapy》2011,13(2):111
It has long been recognized that laboratory tests are useful in the diagnosis of disease and to monitor treatment outcome.
Their performance has become even more demanding with the development of personalized medicine. In patients with rheumatoid
arthritis (RA) the standard biochemical tests measure serological markers of disease, such as C-reactive protein, and RA-associated
auto-antibodies, such as rheumatoid factor and anti-citrullinated protein antibodies. The information obtained from these
markers does not, however, provide a complete picture of the disease and treatment efficacy. New biomarkers based on cytokine
receptor complexes are promising for RA theragnostics. 相似文献
110.
We sequenced the entire control region and portions of flanking genes
(tRNA(Phe), tRNA(Glu), and ND6) in the common chaffinch (Fringilla
coelebs), blue chaffinch (F. teydea), brambling (F. montifringilla), and
greenfinch (Carduelis chloris). In these finches the control region is
similar in length (1,223-1,237 bp) and has the same flanking gene order as
in other birds, and contains a putative TAS element and the highly
conserved CSB-1 and F, D, and C boxes recognizable in most vertebrates.
Cloverleaf-like structures associated with the TAS element at the 5' end
and CSB-1 at the 3' end of the control region may be involved with the stop
and start of D-loop synthesis, respectively. The pattern of nucleotide and
substitution bias is similar to that in other vertebrates, and consequently
the finch control region can be subdivided into a central, conserved G-rich
domain (domain II) flanked by hypervariable 5'-C-rich (domain I) and
3'-AT-rich (domain III) segments. In pairwise comparisons among finch
species, the central domain has unusually low transition/transversion
ratios, which suggests that increased G + T content is a functional
constraint, possibly for DNA primase efficiency. In finches the relative
rates of evolution vary among domains according to a ratio of 4.2 (domain
III) to 2.2 (domain I) to 1 (domain II), and extensively among sites within
domains I and II. Domain I and III sequences are extremely useful in
recovering intraspecific phylogeographic splits between populations in
Africa and Europe, Madeira, and a basal lineage in Nefza, Tunisia. Domain
II sequences are highly conserved, and are therefore only useful in
conjunction with sequences from domains I and III in phylogenetic studies
of closely related species.
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