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101.
The influence of a synthetic adjuvant active glycopeptide, N-acetylmuramyl-l-alanyl-d-isoglutamine (MDP), and of some of its analogs on the in vitro immune response to sheep red blood cells was studied using Mishell and Dutton in vitro stimulation system. When MDP and adjuvant active analogs were incubated with normal spleen cells, increased cell recovery was observed after 3 or 4 days of culture, showing a good correlation between the adjuvant activity in vivo and the enhancement of cell viability in vitro. The analogs which were found to have an adjuvant activity in vivo were equally effective in stimulating in vitro both the background hemolytic PFC and the immune response to sheep red blood cells. However, those which were inactive in vivo were effective in vitro but only at high concentration levels. 相似文献
102.
Alkyl mercaptide complexes of both synthetic and natural-derivative iron(II) porphyrins have been characterized in DMSO solution by proton nmr spectroscopy. A single mercaptide ligand binds to form a high-spin iron(II) complex as determined by solution magnetic measurements and the nmr isotropic shift pattern. Ligand exchange is slow on the nmr time scale unlike corresponding 2-methyl imidazole exchange rates which are very rapid. Further comparison of mercaptide and 2-methyl imidazole adducts reveals a downfield bias in isotropic shift values for the mercaptide species, which may be explained by different signs in the dipolar shift term for the two complexes. This apparent magnetic anisotropy of the mercaptide complex is in the same direction, although smaller, than that observed for bacterial cytochrome P-450. Isotropic shift values of at least 250 ppm for methylene resonances of the coordinated mercaptide support a very efficient unpaired spin delocalization for this axial ligand. 相似文献
103.
Marco Filice Marzia Marciello Lorena Betancor Alfonso V. Carrascosa Jose M. Guisan Gloria Fernandez‐Lorente 《Biotechnology progress》2011,27(4):961-968
Rhizomucor miehei lipase (RML) is greatly hyperactivated (around 20‐ to 25‐fold toward small substrates) in the presence of sucrose laurate. Hyperactivation appears to be an intramolecular process because it is very similar for soluble enzymes and covalently immobilized derivatives. The hyperactivated enzyme was immobilized (in the presence of sucrose laurate) on cyanogen bromide‐activated Sepharose (very mild covalent immobilization through the amino terminal residue), on glyoxyl Sepharose (intense multipoint covalent immobilization through the region with the highest amount of Lys residues), and on different anion exchangers (by multipoint anionic exchange through the region with the highest density of negative charges). Covalent immobilization does not promote the fixation of the hyperactivated enzyme, but immobilization on Sepharose Q retains the hyperactivated enzyme even in the absence of a detergent. The hydrolysis of fish oils by these hyperactivated enzyme derivatives was sevenfold faster than by covalently immobilized derivatives and three and a half times faster than by the enzyme hyperactivated on octyl‐Sepharose. The open structure of the hyperactivated lipase is fairly exposed to the medium, and no steric hindrance should interfere with the hydrolysis of large substrates. These new hyperactivated derivatives seem to be more suitable for hydrolysis of oils by RML immobilized inside porous supports. In addition, the hyperactivated derivatives are fairly stable against heat and organic cosolvents. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011 相似文献
104.
Bj⊘rn Kunoy 《Ocean Development & International Law》2013,44(1):112-130
Where a coastal state intends to delineate, in accordance with Article 76 of the 1982 Law of the Sea Convention, the outer limits of its continental shelf beyond 200 nautical miles, it is to submit scientific and technical data of such proposed limits to the Commission on the Limits of the Continental Shelf within 10 years of the entry into force of the Convention for that state. This obligation has subsequently been subject to a general de facto amendment by which the commencement of the 10-year time frame has been postponed to May 13, 1999, for the states for which the Convention had entered into force prior to the above date. This article discusses whether any provision in the Convention, any subsequent agreement, or any subsequent practice render inoperative the 10-year time frame with regard to those parts of the outer continental shelf that are disputed areas. It is concluded that nothing in the Convention, no subsequent agreements, and no subsequent practice allow for derogation of the 10-year time frame with regard to disputed areas. 相似文献
105.
STANLEY C. FINNEY 《Lethaia: An International Journal of Palaeontology and Stratigraphy》1985,18(4):361-368
A diplograptid graptolite with strongly introverted thecae and unusual thecal processes was isolated from limestones of the Ordovician Pratt Ferry Formation of Alabama and is described as a new species Dicaulograptus cumdiscus. The thecal processes are referred to as pleural disks. They occur in pairs above every thecal aperture and are inferred to have functioned as suspension processes receiving uplift from small-scale turbulent water motion. Such a function is compatible with a passively buoyant mode of life and is difficult to reconcile with an automobile mode of life. 相似文献
106.
Ferdinand Bohlmann Elena Tsankova Jasmin Jakupovic Robert M. King Harold Robinson 《Phytochemistry》1983,22(2):557-560
The investigation of Encelia canescens afforded, in addition to several known compounds, four new dimeric p-hydroxyacetophenone derivatives, two epimeric chromene dimers and two epimeric mixed dimers of euparin and encecalin. Furthermore, derivatives of tremetone and of encecalin were present. The structures were elucidated hy high field 1H NMR spectroscopy. 相似文献
107.
Summary In the pars tuberalis of the hypophysis of Rana temporaria, which shows the ultrastructural characteristics of a polypeptide hormone secreting endocrine gland, seasonal changes of the ultrastructure are described. In accordance with the literature, these seasonal changes of ultrastructure are interpreted as the morphological expression of seasonal changes of endocrine activity of the pars tuberalis. 相似文献
108.
Graham Bell 《Journal of evolutionary biology》1988,1(1):67-82
Asexual populations irreversibly accumulate mildly deleterious mutations through the occasional stochastic loss of their least-loaded line, a process known as “Muller's Ratchet”. This paper explores the dynamics of this process, and the role of recombination in halting the Ratchet. Simulation studies show that an optimal class comprising no individuals is lost in about 10no generations, implying that adaptedness may deteriorate rather rapidly in geological time. Asexual organisms will persist only if they are very numerous, or if they have very small genomes, or if there is extensive negative interaction among nonallelic mutations. Otherwise, long-term persistence requires that unloaded genomes be continually generated by recombination. An approximate expression for the rate of recombination needed to halt the Ratchet is developed, and shows that substantial recombination is necessary in populations of fewer than about 1010 individuals. A further complication is introduced by mutations in sequences which specify proofreading enzymes. Since these will reduce the fidelity of their own replication, a process of positive feedback leading to an ever-accelerating loss of function is conceivable. 相似文献
109.
Dr. N. J. D. Nagelkerke A. A. M. Hart J. Oosting 《Biometrical journal. Biometrische Zeitschrift》1987,29(2):141-145
The consequences of the misspecification of a regression model are considered. For small effects of covariates a proportional consistency theorem is derived. The consistent estimation of the covariance matrix of the estimates is discussed. 相似文献
110.