scholarly journals Activation of CLN1 and CLN2 G1 cyclin gene expression by BCK2.

1995 ◽  
Vol 15 (4) ◽  
pp. 1835-1846 ◽  
Author(s):  
C J Di Como ◽  
H Chang ◽  
K T Arndt

The Saccharomyces cerevisiae CLN3 protein, a G1 cyclin, positively regulates the expression of CLN1 and CLN2, two additional G1 cyclins whose expression during late G1 is activated, in part, by the transcription factors SWI4 and SWI6. We isolated 12 complementation groups of mutants that require CLN3. The members of one of these complementation groups have mutations in the BCK2 gene. In a wild-type CLN3 genetic background, bck2 mutants have a normal growth rate but have a larger cell size, are more sensitive to alpha-factor, and have a modest defect in the accumulation of CLN1 and CLN2 RNA. In the absence of CLN3, bck2 mutations cause an extremely slow growth rate: the cells accumulate in late G1 with very low levels of CLN1 and CLN2 RNA. The slow growth rate and long G1 delay of bck2 cln3 mutants are cured by heterologous expression of CLN2. Moreover, overexpression of BCK2 induces very high levels of CLN1, CLN2, and HCS26 RNAs. The results suggest that BCK2 and CLN3 provide parallel activation pathways for the expression of CLN1 and CLN2 during late G1.

2020 ◽  
Author(s):  
E.N. Lipets ◽  
O.A. Antonova ◽  
O.N. Shustova ◽  
K.V. Losenkova ◽  
A.V. Mazurov ◽  
...  

Background and objectiveFor many pathological states, microparticles are supposed to be one of the causes of hypercoagulation. Although there are some indirect data about microparticles participation in coagulation activation and propagation, the integral hemostasis test Thrombodynamics allows to measure micropaticles participation in these two coagulation phases directly by influence on the appearance of coagulation centers in plasma volume and on the rate of clot grown from surface with immobilized tissue factor.MethodsMicroparticles were obtained from platelets and erythrocytes by stimulation with SFLLRN and A23187, respectively, from monocytes, endothelial HUVEC culture and monocytic THP cell culture by stimulation with lipopolysaccharides. Microparticles were counted by flow cytometry and titrated in microparticle-depleted normal plasma in the Thrombodynamics test.ResultsMonocyte microparticles induced the appearance of clotting centres through the TF pathway at concentrations approximately 100-fold lower than platelet and erythrocyte microparticles, which activated plasma by the contact pathway. For endothelial microparticles, both activation pathways were essential, and their activity was intermediate. Monocyte microparticles induced plasma clotting by the appearance of hundreds of clots with an extremely slow growth rate, while erythrocyte microparticles induced the appearance of a few clots with a growth rate similar to that from surface covered with high-density tissue factor. Patterns of clotting induced by platelet and endothelial microparticles were intermediate. Platelet, erythrocyte and endothelial microparticles impacts on the rate of clot growth from the surface with tissue factor did not differ significantly within the 0-200·103/ul range of microparticles concentrations. However, at concentrations greater than 500·103/ul, erythrocyte microparticles increased the stationary clot growth rate to significantly higher levels than do platelet microparticles or artificial phospholipid vesicles consisting of phosphatidylcholine and phosphatidylserine.ConclusionMicroparticles of different origins demonstrated qualitatively different characteristics related to coagulation activation and propagation.


1986 ◽  
Vol 34 (3) ◽  
pp. 351 ◽  
Author(s):  
A Lill

Estimated expenditures on brood-care by unassisted female superb lyrebirds, obtained through time-energy budgeting, were compared with published values for other bird species. With the exception of nestbuilding, estimated daily expenditures were relatively low, due mainly to the small brood size and low level of parental attentiveness. It is suggested that the traits which reduce daily brood-care expenditures, particularly the small brood size and extremely slow growth rate, may have evolved as adaptations which enabled deserted females operating close to maximal capacity to cope with single-parenting. Male parental involvement could probably increase the growth rate of the young, but not brood size; moreover, egg- laying was sufficiently asynchronous to afford multiple mating opportunities to parentally emancipated males. However, the slow growth rate of the young results in relatively large overall brood-care expenditures for females. Investments by males of up to 50% of daylight hours and 45% of BMR on singing at the height of the mating season were comparable with those of partially emancipated, polygynous males of other species. They probably reflect the high level of competition to control good display areas and to advertise status and quality to widely spaced females.


1970 ◽  
pp. 01-07
Author(s):  
Saumitro Das ◽  
L.K. Jha

The natural population of Taxus baccata L. (Himalayan Yew) throughout the Indian Himalayan Region is greatly reduced due to its extensive and reckless exploitation for “Taxol” an anticancer drug. The effects of overexploitation are exacerbated by the species poor regeneration process, slow growth rate and prolonged seed dormancy. Therefore vegetative propagation by branch cuttings seems to be only practical solution for its large scale multiplication. A study was conducted on six candidate trees (CTs) to examine the effect genotype, physiological age of stem, IBA treatment on rooting of Taxus baccata cuttings. Results revealed that rooting behaviour of cuttings was significantly affected by all the factors under study. Among the six CTs studied, CT 2 (from BSI, Shillong) had given the highest rooting response (46.28%). The juvenile cuttings have the higher rooting capacity; however the callusing was more prominent in mature cutting. The influence of IBA treatment was also significant for rooting where 1000 was most effective for stimulating rooting juvenile cuttings and 2000 ppm in mature cuttings.


2019 ◽  
Vol 63 (12) ◽  
Author(s):  
Charlotte L. Hendon-Dunn ◽  
Henry Pertinez ◽  
Alice A. N. Marriott ◽  
Kim A. Hatch ◽  
Jon C. Allnutt ◽  
...  

ABSTRACT Modulation of the growth rate in Mycobacterium tuberculosis is key to its survival in the host, particularly with regard to its adaptation during chronic infection, when the growth rate is very slow. The resulting physiological changes influence the way in which this pathogen interacts with the host and responds to antibiotics. Therefore, it is important that we understand how the growth rate impacts antibiotic efficacy, particularly with respect to recovery/relapse. This is the first study that has asked how growth rates influence the mycobacterial responses to combinations of the frontline antimycobacterials, isoniazid (INH), rifampin (RIF), and pyrazinamide (PZA), using continuous cultures. The time course profiles of log-transformed total viable counts for cultures, controlled at either a fast growth rate (mean generation time [MGT], 23.1 h) or a slow growth rate (MGT, 69.3 h), were analyzed by the fitting of a mathematical model by nonlinear regression that accounted for the dilution rate in the chemostat and profiled the kill rates and recovery in culture. Using this approach, we show that populations growing more slowly were generally less susceptible to all treatments. We observed a faster kill rate associated with INH than with RIF or PZA and the appearance of regrowth. In line with this observation, regrowth was not observed with RIF exposure, which provided a slower bactericidal response. The sequential additions of RIF and PZA did not eliminate regrowth. We consider here that faster, early bactericidal activity is not what is required for the successful sterilization of M. tuberculosis, but instead, slower elimination of the bacilli followed by reduced recovery of the bacterial population is required.


1989 ◽  
Vol 257 (4) ◽  
pp. E554-E560
Author(s):  
S. A. Norton ◽  
M. T. Zavy ◽  
C. V. Maxwell ◽  
D. S. Buchanan ◽  
J. E. Breazile

Twelve-hour plasma profiles of growth hormone (GH), insulin, glucose, and nonesterified free fatty acids (NEFA), as well as GH, insulin, and glucose responses to saline, glucose, arginine, and human pancreatic growth hormone-releasing factor (GRF) infusion were examined in 15 crossbred gilts, selected for rapid vs. slow growth. For experiment 1 GH and insulin patterns differed (P less than 0.05) between the rapid growth line (RGL) and slow growth line (SGL). Mean GH concentrations in SGL and RGL gilts were 4.1 and 3.2 ng/ml, respectively (P less than 0.05). Plasma GH profile area was greater (P less than 0.08) for SGL than RGL gilts. Glucose level, glucose area, and insulin level were higher (P less than 0.05) for RGL than SGL gilts. Plasma NEFA levels and area were greater (P less than 0.05) for SGL gilts. In experiment 2 responses of GH, insulin, and glucose to saline, glucose, arginine, and GRF infusions varied (P less than 0.05) between and within lines relative to control values. These results indicate that selection for growth rate results in concomitant changes in endocrine and metabolic status.


1946 ◽  
Vol 5 (1) ◽  
pp. 3-15 ◽  
Author(s):  
J. L. Krider ◽  
B. W. Fairbanks ◽  
W. E. Carroll ◽  
E. Roberts

2012 ◽  
Vol 706-709 ◽  
pp. 859-864 ◽  
Author(s):  
Kum Hee Seo ◽  
Bok Hyun Kang ◽  
Ki Young Kim

A new way to melt and refine recycled silicon powders from the wafer back grinding wastes was proposed. We designed a new equipment using induction heating for the fast melting and directional solidification of the recycled silicon powders, and investigated the feasibility of utilizing them as silicon feedstock for solar cells through lab-scale experiments on the melting and refining them. Silicon particles recovered from back grinding slurry were flake like and very fine, about 3um and was covered with very thin silicon oxide. Slag was observed on the top of the melt during melting, which was composed of oxygen, silicon and carbon which was believed to come from the graphite crucible. Complete melting and subsequent feeding of powders into the melt were prevented by the slag formed during melting, which could be solved by changing the melting atmosphere. Slow growth rate made the impurities such as Al, Ti, Fe, Zr segregate to the top of the ingot purifying the lower part. Over 5N purity was obtained in the middle and lower part of the ingot by the fast melting and directional solidification.


2001 ◽  
Vol 696 ◽  
Author(s):  
Marie-José Casanove ◽  
Pierre Baulès ◽  
Christian Roucau ◽  
David Magnoux ◽  
Jean-François Bobo ◽  
...  

AbstractEpitaxial growth of La1-x(SrorCa)xMnO3 manganites (LSMO or LCMO) has been successfully achieved on SrTiO3 (001) and MgO(001) substrates. We report the influence of the deposition conditions, in particular growth rate, annealing and nature of the substrate, on the state of strain in the manganite layers. Fully strained layers are reported at very slow growth rate on SrTiO3 substrates while misfit dislocations are clearly observed in layers grown on MgO and alsoin layers grown on SrTiO3, after annealing at high temperature. Besides, evidence is given for a rhombohedral (respectively orthorhombic) distortion relaxation in LSMO (respectively LCMO) layers. The microstructure of the manganite layers is analyzed taking into account their non-isomorphic growth on the cubic substrates.


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