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91.
1. The activities of l-ornithine decarboxylase (EC 4.1.1.17) and S-adenosyl-l-methionine decarboxylase (EC 4.1.1.50) were dramatically enhanced in both the ventral prostate and the seminal vesicle of castrated rats in response to androgenic stimulation. The time course of the stimulation of ornithine decarboxylase together with the quantitatively different response of adenosylmethionine decarboxylase to testosterone treatment in the prostate gland and seminal vesicle indicated that the enhancement in polyamine synthesis in the ventral prostate may reflect both cellular proliferation and the restoration of the secretory functions of the organ. In the seminal vesicle, however, the stimulation of the polyamine-biosynthetic pathway more closely resembled the pattern found in other rat tissues, such as regenerating liver, undergoing compensatory growth. 2. Ornithine decarboxylase activity in the ventral prostate and especially in the seminal vesicle of sexually mature rat was diminished in vivo by various short-chain diamines such as 1,2-diaminoethane, 1,3-diaminopropane and putrescine (1,4-diaminobutane). These diamines had no direct effect on the enzyme activity in vitro. 3. In contrast with the marginal decrease in ornithine decarboxylase activity produced by diaminoethane in the ventral prostate of non-castrated animals, repeated injections of the latter amine completely prevented the intense stimulation of the enzyme activity in the ventral prostate and seminal vesicle of castrated rats at 24h after the commencement of testosterone treatment. 4. The decrease in ornithine decarboxylase activity observed after injections of diamines (putrescine) in the ventral prostate was apparently associated with a similar decrease in the amount of immunoreactive protein as revealed by immunotitration of the enzyme with antiserum to rat ornithine decarboxylase. 相似文献
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Prakash P. Praharaj Sujit K. Bhutia Sunitha Nagrath Rhonda L. Bitting Gagan Deep 《生物化学与生物物理学报:癌评论》2018,1869(2):117-127
Traditional 2D cell cultures do not accurately recapitulate tumor heterogeneity, and insufficient human cell lines are available. Patient-derived xenograft (PDX) models more closely mimic clinical tumor heterogeneity, but are not useful for high-throughput drug screening. Recently, patient-derived organoid cultures have emerged as a novel technique to fill this critical need. Organoids maintain tumor tissue heterogeneity and drug-resistance responses, and thus are useful for high-throughput drug screening. Among various biological tissues used to produce organoid cultures, circulating tumor cells (CTCs) are promising, due to relative ease of ascertainment. CTC-derived organoids could help to acquire relevant genetic and epigenetic information about tumors in real time, and screen and test promising drugs. This could reduce the need for tissue biopsies, which are painful and may be difficult depending on the tumor location. In this review, we have focused on advances in CTC isolation and organoid culture methods, and their potential applications in disease modeling and precision medicine. 相似文献
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The feeding stimulant for the smaller European elm bark beetle has been revised to (+)-catechin 7-β-d-xylopyranoside (III) from the structure (I) bearing the sugar at the 5-position. 相似文献
96.
Cationic polyacrylamides (c-PAMs) increase the binding of cellulase to cellulose and of α-amylase to cornstarch. The c-PAMs increase the rate of hydrolysis of both substrates by about the same amount, which suggests that the increased binding is responsible for the enhanced rates. These results support our proposed mechanism where the c-PAM neutralizes the charge of the substrate through a “patching” mechanism, which reduces the charge repulsion between fiber and enzyme. 相似文献
97.
Cationic polyelectrolytes can increase the cellulase-induced hydrolysis rates of bleached wood fiber. We show that the polymer
associates mainly with the amorphous region of fiber and acts principally on endoglucanase. Fiber/water partitioning of the
enzyme follows a Langmuir isotherm for the untreated fiber but a Freundlich isotherm is obeyed for the polymer-treated fiber. 相似文献
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Sujit Kumar Ghosh Dewan S. Rahman Abdul Latif Ali Anamika Kalita 《Plasmonics (Norwell, Mass.)》2013,8(3):1457-1468
Ultrasmall copper nanoparticles have been synthesized using copper(II) salt as precursor by hydrazine reduction in the presence of citric acid and cetyltrimethylammonium bromide facilitating the growth of stable copper nanoparticles with an average diameter of <2 nm. The corresponding surface plasmon resonances were monitored under variable microenvironments, and it is seen that these tiny copper nanoparticles form aggregates under stipulated reaction conditions. It is noted that ultrasmall copper nanoparticles do not exhibit any characteristic surface plasmon band in the visible region; rather, a continuous absorption is seen over the entire UV–vis region. However, a well-defined plasmon absorption band makes its appearance while the particles are aggregated in close-packed assembly. These results demonstrate that the maximum of surface plasmon resonance is red-shifted from that of isolated particles because of electromagnetic interaction between the particles. The aggregation process is manifested upon changes of pH, anionic surfactant, etc. and is not reversible, i.e., the aggregates could not be re-dispersed into ultrasmall particles. The effect of addition of electrolyte has been monitored to study the surface plasmon damping of the copper nanoparticles. The plasmonic sensitivity of the copper nanoparticle aggregates has been elicited by the determination of amino acid chain length with exquisite sensitivity because of enormous electromagnetic field at the junction of the particles in the aggregates. Interestingly, the as-synthesized ultrasmall copper nanoclusters exhibit excellent fluorescence properties with a narrow emission profile. The emission properties of these copper nanoclusters have been utilized as an indicator for selective and ultrasensitive detection of highly toxic HgII ions in water in the nanomolar detection limit. 相似文献
100.
Young Ae You Mohammad Ali Suman Kanungo Binod Sah Byomkesh Manna Mahesh Puri G. Balakrish Nair Sujit Kumar Bhattacharya Matteo Convertino Jacqueline L. Deen Anna Lena Lopez Thomas F. Wierzba John Clemens Dipika Sur 《PloS one》2013,8(8)