Precocene treatment does not disrupt the events of reproduction in G. m. morsitans or induce any apparent changes in treated tsetse. Some females of the f1 generation are either sterile or show retardations in follicl...
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Precocene treatment does not disrupt the events of reproduction in G. m. morsitans or induce any apparent changes in treated tsetse. Some females of the f1 generation are either sterile or show retardations in follicle development. Sterility is not reversed spontaneously or with juvenile hormone analogs. The critical period for precocene action is related to each ovulation. The corpora allata of precocene-treated tsetse are normal, but those off1 sterile females are degenerate. The occurrence of retardation has enabled the characterization of stages in follicle development in G. m. morsitans.
The leaf alkanes of P. argentatum (guayule), P. tomentosum var. stramonium, P. fruticosum var. trilobatum, and the 1st filial (f1) generations obtained from crosses with guayule were investigated by GC [gas chromatogr...
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The leaf alkanes of P. argentatum (guayule), P. tomentosum var. stramonium, P. fruticosum var. trilobatum, and the 1st filial (f1) generations obtained from crosses with guayule were investigated by GC [gas chromatography] and mass spectrometry[ms] and are useful in chemotaxonomic studies. The identified n-alkanes ranged from C19 to C40 with either n-C29 or n-C31 as the main component. The alkane chemistry of guayule with n-C31 being the main component predominated in most of the f1 hybrids. The presence of iso-branched alkanes (C27, C29, C31) in P. tomentosum and its hybrids could be detected by GC/MS. These preliminary investigations indicate that epiculticular wax alkanes can be useful in inheritance studies of guayule and its hybrids.
Denote C0（I, I） as the set of all continuous mappings of the interval. Let f∈C0（I, I）, for any positive integer n, we define fn inductively byf1= f, fn=f·fn-1 and f0=the identity *** 1. Let p∈I. If. there e...
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Denote C0（I, I） as the set of all continuous mappings of the interval. Let f∈C0（I, I）, for any positive integer n, we define fn inductively byf1= f, fn=f·fn-1 and f0=the identity *** 1. Let p∈I. If. there exists a positive integer n, such that fn（p）=p, then p is called a periodic point off.
It is known that the distributions of statistics commonly used in experimental design (notably the f statistic) involve certain nuisance parameters which depend on the model and the design. Raudomization was a techniq...
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It is known that the distributions of statistics commonly used in experimental design (notably the f statistic) involve certain nuisance parameters which depend on the model and the design. Raudomization was a technique introduced by R.A. fisher to eliminate some of these parameter and produce a usable distribution function. We will show that there is a close relationship between the analytical properties of the non-randomized distribution and the more combinatorial properties of the nuisance parameters. This relationship allows us to determine theoretically, and practically in some cases, how good an approximation the central f distribution is to the randomized distribution.
A method is described to prepare an ATPase-ATP synthase complex from pig heart mitochondria exhibiting a very high ATP-32Pi exchange activity (1.6 .***/min per mg protein in optimal conditions). The preparation is vir...
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A method is described to prepare an ATPase-ATP synthase complex from pig heart mitochondria exhibiting a very high ATP-32Pi exchange activity (1.6 .***/min per mg protein in optimal conditions). The preparation is virtually devoid of nucleoside diphosphokinase and adenylate kinase activities. freeze-fracture studies show that the ATPase-ATP synthase complex is integrated in lipid vesicles of 400-600 .ANG. in diameter. It contains the endogenous natural proteic inhibitor which seems to behave as a coupling factor. The rate of ATP hydrolysis catalyzed by the ATPase-ATP synthase complex is competitively inhibited by ADP, while the presence of ADP increases the initial rate of 32Pi incorporation into ATP. The 32Pi incorporation into ATP can occur at a rate almost equal to that of nucleoside triphosphate (NTP) hydrolysis provided that the rate of NTP hydrolysis is kept low and that the ADP concentration is high enough. In these conditions, a very high coupling between NTP hydrolysis and ATP synthesis can be demonstrated.
作者：
YAARI, AMUNIV PENN
SCH DENT MED DEPT ORTHODONT PEDODONT PHILADELPHIA PA 19104 USA UNIV PENN
SCH DENT MED CTR ORAL HLTH RES PHILADELPHIA PA 19104 USA
Experiments to study the effect off- on phosphatidylserine-mediated Ca2+ transport were performed utilizing 2 and 3 compartment lipid-aqueous phase model systems. Using the 3 compartment model, it was shown f- modula...
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Experiments to study the effect off- on phosphatidylserine-mediated Ca2+ transport were performed utilizing 2 and 3 compartment lipid-aqueous phase model systems. Using the 3 compartment model, it was shown f- modulated the rate of Ca2+ transport in a biphasic manner. Low concentrations off- enhanced the Ca2+ translocation rate and high levels off- inhibited the rate of Ca2+ transport. To determine whether the enhancement or inhibition of Ca2+ transport rate by f- was due to an increase in the uptake of Ca2+ into the lipid phase, or to an increase in the ability of the lipid phase to release Ca2+, a 2 compartment model was used. The ability of the phosphatidylserine phase to take up Ca2+ increased as the f- concentration of the aqueous donor phase was raised. In addition, Ca2+ release from the phosphatide was also modulated by f-. High f- levels inhibited the release of Ca2+ from the lipid, while low levels off- did not retain Ca2+ in the lipid phase. Thus, f- enhanced the interaction between Ca2+ and phosphatidylserine, possibly by forming a phosphatidylserine-Ca-f complex. Once this interaction had taken place, Ca2+ release into the aqueous receiver compartment was dependent on the f- concentration. Thus, low f- levels induced a net increase in Ca2+ transport, while high f- levels inhibited Ca2+ translocation rates.
fluorescence induction curves in 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU)-inhibited Photosystem (PS) II particles isolated from the blue-green alga P. laminosum were analyzed as a function of redox potential. Re...
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fluorescence induction curves in 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU)-inhibited Photosystem (PS) II particles isolated from the blue-green alga P. laminosum were analyzed as a function of redox potential. Redox titration of the initial fluorescence indicated a single component with Em,7.5 = +30 mV (n = 1). Despite this simplified electron acceptor system and the small number of chlorophylls per reaction center, a sigmoidal induction curve was seen. Sigmoidicity decreased as Q was reduced potentiometrically prior to induction such that the induction was exponential when the ratio fi/fm = 0.64 [fi = initial fluorescence, fm = maximum fluorescence]. These particles also showed a slow (.beta.) phase of induction which titrated with an Em value slightly more positive than that of the major quencher. The sigmoidal shape of the fluorescence induction curve observed in Phormidium PS II particles is not a consequence of a requirement for 2 photons to close the PS II reaction center but is generated as a result of energy transfer between photosynthetic units comprising 1 reaction center/.apprx. 50 chlorophylls. Also, the existence of PS II heterogeneity (PS II ***., PS ***. centers) does not require a structurally differentiated chloroplast but may only indicate the extent of aggregation of PS II centers.
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