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91.
ELBIETA M. STEFANIUK ALEKSANDRA KOZISKA IZABELA WA
KO ANNA BARANIAK STEFAN TYSKI 《Polish journal of microbiology》2021,70(2):283
Sixty-five colistin-resistant Enterobacterales isolates recovered from different clinical specimens were analyzed. The strains were collected in 12 hospitals all over Poland within a period of nine months. Strains were analyzed for eight genes from the mcr family. The presence of mcr-1 gene was detected in three Escherichia coli strains. The 45/65 isolates were identified as ESBL producers. CTX-M-1-like enzymes were the most common ESBLs (n = 40). One E. coli and seven Klebsiella pneumoniae strains produced carbapenemases, with the NDM being produced by five isolates. Among all the strains tested, four and five were resistant to new drugs meropenem/vaborbactam and ceftazidime/avibactam, respectively. 相似文献
92.
YING SUN LIANHONG GU ROBERT E. DICKINSON STEPHEN G. PALLARDY JOHN BAKER YONGHUI CAO FÁBIO MURILO DAMATTA XUEJUN DONG DAVID ELLSWORTH DAVINA VAN GOETHEM ANNA M. JENSEN BEVERLY E. LAW RODOLFO LOOS SAMUEL C. VITOR MARTINS RICHARD J. NORBY JEFFREY WARREN DAVID WESTON KLAUS WINTER 《Plant, cell & environment》2014,37(4):978-994
Worldwide measurements of nearly 130 C3 species covering all major plant functional types are analysed in conjunction with model simulations to determine the effects of mesophyll conductance (gm) on photosynthetic parameters and their relationships estimated from A/Ci curves. We find that an assumption of infinite gm results in up to 75% underestimation for maximum carboxylation rate Vcmax, 60% for maximum electron transport rate Jmax, and 40% for triose phosphate utilization rate Tu. Vcmax is most sensitive, Jmax is less sensitive, and Tu has the least sensitivity to the variation of gm. Because of this asymmetrical effect of gm, the ratios of Jmax to Vcmax, Tu to Vcmax and Tu to Jmax are all overestimated. An infinite gm assumption also limits the freedom of variation of estimated parameters and artificially constrains parameter relationships to stronger shapes. These findings suggest the importance of quantifying gm for understanding in situ photosynthetic machinery functioning. We show that a nonzero resistance to CO2 movement in chloroplasts has small effects on estimated parameters. A non‐linear function with gm as input is developed to convert the parameters estimated under an assumption of infinite gm to proper values. This function will facilitate gm representation in global carbon cycle models. 相似文献
93.
LAURA POLITI EMILIA CHIANCONE LAURA GIANGIACOMO LAURA CERVONI ANNA SCOTTO D’ABUSCO STEFANO SCORSINO ROBERTO SCANDURRA 《Archaea (Vancouver, B.C.)》2009,2(4):221-231
Recombinant amidase from Sulfolobus solfataricus
occurred as a dimer of 110 kDa comprising identical subunits.
Only dimers were present at pHs above 7.0, but with decreasing pH,
dimers associated into octamers, with complete oligomerization
occurring at pH 3.0. Oligomerization showed reversible
temperature-dependence, with octamer formation increasing with
temperature from 36 °C to between 70 and 80° C. Increasing
salt concentrations, favored dissociation of the octamers. Among the
three investigated factors affecting the dimer–octamer
equilibrium, the most important was pH. Among four mutants obtained by
site-specific mutagenesis and selection for pH and temperature
sensitivity, the T319I and D487N mutant amidases, like that of the
native Sulfolobus solfataricus, responded to changes
in pH and temperature with a conformational change affecting the
dimer–octamer equilibrium. The Y41C and L34P mutant amidases
were unaffected by pH and temperature, remaining always in the dimeric
state. The differences among mutants in protein conformation must be
related to the position of the introduced mutation. Although the L34P
and Y41C mutations are located in the helical region 33–48
(LLKLQLESYERLDSLP), which is close to the amino-terminal segment of
the protein, the T319I mutation is located in a strand on the surface
of the protein, which is far from, and opposite to, the amino-terminal
segment. The D487N mutation is located in the center of the protein,
far distant from the 33–48 segment. These observations suggest
that the segment of the protein closest to the amino-terminus plays a
key role in the association of dimers into octamers. 相似文献
94.
ANNA ZEFFER L. CHRISTOFFER JOHANSSON ÅSA MARMEBRO 《Biological journal of the Linnean Society. Linnean Society of London》2003,79(3):461-484
Many of the morphological features of animals are considered to be adaptations to the habitat that the animals utilize. The habitats utilized by birds vary, perhaps more than for any other group of vertebrates. Here, we study possible adaptations in the morphology of the skeletal elements of the hind limbs to the habitat of birds. Measurements of the lengths of the femur, tibiotarsus and tarsometatarsus of 323 bird species from 74 families are used together with body mass data, taken from the literature. The species are separated into six habitat groups on the basis of literature data on leg use. A discriminant analysis of the groups based on leg morphology shows that swimming birds, wading birds and ground living species are more easily identified than other birds. Furthermore, functional predictions are made for each group based on ecological and mechanical considerations. The groups were tested for deviation from the norm for all birds for three indices of size- and leg-length-independent measures of the bones and for a size-independent-index of leg length. Several of the groups deviate significantly from the norm for one or more of the indices used, suggesting habitat-related adaptations in the leg morphology of birds. The results indicate that stability is an important factor affecting the leg morphology of primarily long-legged birds. The femur seems to be more important than previously thought because several of the groups have high femur indices, suggesting a positive selection pressure on this bone. On a general basis, the results suggest that the effect of leg length should be taken into consideration when discussing adaptations of mass-independent lengths of the long bones of the legs of birds. © 2003 The Linnean Society of London, Biological Journal of the Linnean Society , 2003, 79, 461–484. 相似文献
95.
Photosynthetic activities of cadmium-treated tomato plants 总被引:20,自引:0,他引:20
TADEUSZ BASZYKI LUCYNA WAJDA MARIA KRÓL DANUTA WOLISKA ZBIGNIEW KRUPA ANNA TUKENDORF 《Physiologia plantarum》1980,48(3):365-370
Tomato plants (Lycopersicum esculentum Mill. cv. Moneymaker) grown on nutrient medium containing cadmium exhibit reduced net photosynthesis and reduced contents of chlorophyll and accessory pigments. In chloroplasts isolated from cadmiumtreated plants photosystem II activity, as measured by 2,6-dichlorophenolindophenol photoreduction, and photosystem II + I activity (H2O → methyl viologen) were both inhibited to about 60%. When 1,5-diphenylcarbazide was used as artificial electron donor, no significant cadmium effect was observed. Photosystem I activity was not affected by cadmium. The fine structure of chloroplasts in cadmium-treated plants was degenerated, similarly to senescence response. The principal symptom of cadmium action was the occurrence of large plastoglobules and a disorganization of the lamellar structure, mainly grana stacks. Transfer of cadmium-treated plants into a medium with increased manganese level caused grana stacking and restoration of photosystem II activity. 相似文献
96.
97.
98.
CATECHOLAMINES probably influence cell proliferation by delaying cells in the premitotic phase1,2. Bullough and Laurence found that crude skin extracts contained a tissue-specific protein (chalone) which inhibited epidermal cell proliferation and that the action of this extract was augmented by adrenaline3. They later found that adrenaline alone (0.00025 µg/ml.) reduced epidermal mitotic activity in mouse ears by about 50% in vitro4. 相似文献
99.
Some virus and virus-like diseases of tobacco,tomato, papaya,and rubber tree in vietnam and cambodia
In Vietnam a green strain of tobacco mosaic virus was isolated having TIP 89°C (10 min) and causing systemic necrosis in tobacoo ‘Xanthi-nc’ and sometimes also inDatura stramonium. In symptomless tomato plants an elongated virus belonging apparently to the Carlavirus group (NL 630 nm) was found. In papaya trees showing severe symptoms of mosaic and/or ringspot elongated virus particles (NL 730 nm) were observed; this virus being apparently a member of the Potyvirus group, resembled as far as its symptoms in papaya are concerned, the papaya ringspot or the distortion ringspot. In Cambodia some young rubber trees showed malformed leaves (esp. edges and veins) with yellow discolorations along the veins. Such leaves contained elongated virus-like particles (rigid or slightly flexible) of various length (60 to 880 nm), so that their normal length (NL) could not be established precisely. Particles 120 to 150 nm long occurred very frequently. 相似文献
100.