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51.
The study was designed to determine whether methionine-enkephalin (M-ENK) was present in the digestive system of the scallop
Chlamys farreri and investigate the effects of M-ENK on the activity of amylase, protease and lipase in the digestive system of C. farreri. The results indicated that M-ENK-like material was present in the epithelium and connective tissue of labial palps, mouth
labia, stomach, intestine, rectum, and hepatopancreas of the scallop C. farreri. Moreover, it was also found that many isolated small cells showing M-ENK-like immunoreactivity were scattered in the epithelial
layer of intestine, and many isolated big epithelial cells showing M-ENK-like immunoreactivity were scattered in tubules of
hepatopancreas of the scallop. The activity levels of amylase and lipase in crystalline style, hepatopancreas and intestine
were enhanced at 1 h after injection of exogenous M-ENK into adductor muscle of the scallops, whereas protease activity levels
were significantly suppressed. Our report constitutes the first characterization of M-ENK in the digestive system of scallop
C. farreri and investigates the effects of M-ENK on the activities of digestive enzymes of mollusk for the first time. The results suggest
an involvement of M-ENK in the functional regulation of the digestive system of C. farreri. 相似文献
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The quantitative autoradiographic L-[1-14C]leucine method for the determination of regional rates of cerebral protein synthesis in vivo takes into account recycling of unlabeled leucine derived from protein degradation into the precursor pool for protein synthesis. We have evaluated the degree of recycling by measuring the ratio of the apparent steady-state leucine specific activity in the precursor amino acid pool (tRNA-bound leucine) to that in the arterial plasma. In the whole brain of the conscious rat this ratio (lambda WB) equals 0.58. The equivalent ratio for leucine in the acid-soluble pool in whole brain (psi WB) is 0.49. A first-degree polynomial equation for lambda WB as a function of psi WB was fitted from paired determinations. To determine the degree of recycling in local regions of the brain, we have measured in individual brain regions (i) psi i and calculated lambda i assuming that the fitted equation also applies to these localized regions. Our results indicate that the degree of recycling into the precursor pool does vary regionally; lambda i in the individual regions varies from 0.62 in the hypoglossal nucleus to 0.50 in the globus pallidus. Local rates of protein synthesis were then determined by the autoradiographic technique with regional corrections for recycling of unlabeled leucine. Rates of leucine incorporation into protein averaged 6.1 nmol/g of tissue/min in the brain as a whole, with the rates in gray matter about twice those in white matter. 相似文献
55.
Yan-Hong He Guo-Gui Ning Ya-Lin Sun Yan Hu Xing-Yu Zhao Man-Zhu Bao 《Molecular breeding : new strategies in plant improvement》2010,26(1):19-29
A male sterile line was isolated in marigold (Tagetes erecta L.) and cytological analysis determined this to be a novel genic male sterility trait (Tems). Through the use of amplified fragment length polymorphisms (AFLPs) and bulked segregant analysis (BSA), tightly linked
markers of Tems were identified with a view towards a map-based cloning strategy. It was found that spontaneous homeotic conversion of floral
organs was the underlying cause of the male sterility in this marigold line. Thus, petals of male sterile plants resembled
sepal-like structures and the stamens were partially converted to styles, although without the full characteristics or function
of the true style organs. We have constructed a fine marker-based map for the Tems gene. This is intended to provide a tool for marker assisted selection (MAS) strategies in hybrid breeding and map-based
cloning strategies for the male sterility locus. We discuss the significance of this spontaneously derived genic male sterility
trait relating to the homeotic conversion of floral organs in marigold. 相似文献
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W H Sun B Stebler W B Ershler 《Biochemical and biophysical research communications》1991,179(1):675-682
We have shown that certain murine tumors grow more slowly and spread less readily in immune deficient animals. We have also demonstrated that immunologic factors explain certain aspects of this difference. In the work presented we demonstrate that a subpopulation of splenocytes produce a factor(s) that enhances tumor cell proliferation in vitro. We also describe an in vitro model to determine the level of tumor stimulatory activity. We found that the tumor cell growth-enhancing activity (TEA) is heat stable but sensitive to trypsin digestion, low pH and beta-mercaptoethanol. TEA production is found to be insensitive to mitogen stimulation such as concanavalin A, lipopolysaccharide, and phytohemagglutinin. Among the known growth factors and interleukins we have tested (interleukin 1-7, basic FGF, EGF, TGF-beta PDGF, GM-CSF, and MCSF), none appear to account for TEA activity. 相似文献
60.
Following the rapid uplift of the Qinghai-Tibetan Plateau, the reorganization of the major river drainages in southwest China
was primarily caused by river capture events. However, the impact of these past changes in drainage patterns on the current
distribution and genetic structure of the endemic flora of this region remains largely unknown. Here we report a survey of
amplified fragment length polymorphism (AFLP) in Terminalia franchetii, an endemic shrub or small tree of the deep and dry-hot river valleys of this region. We surveyed AFLP variation within and
among 21 populations (251 individuals) of T. franchetii, distributed disjunctively between northern and southern drainage systems. Using STRUCTURE, principal coordinates analysis,
and genetic distance methods, we identified two main population genetic groups (I and II) and four subgroups within the species,
as follows: (I) the Upper Jinshajiang Valley (subgroup I(north)) and the Honghe drainage area (subgroup I(south)); (II) the Middle and Lower Jinshajiang and Yalongjiang Valleys (subgroup II(north)) and the Nanpanjiang drainage area (subgroup II(south)). Genetic diversity was lower in group I than in group II. According to the genetic diversity and genetic structure results,
we suggest that the modern disjunctive distribution and associated patterns of genetic structure of T. franchetii result from vicariance caused by several historical drainage capture events, involving the separation of the Upper Jinshajiang,
Yalongjiang and Daduhe from the Honghe or Nanpanjiang in southwest China. 相似文献