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1.
Summary Maximum lipase production byAspergillus foetidus was obtained from cultures grown in the medium of 2% olive oil and 0.5% sucrose. The optimal conditions for the production of lipases in the Multigen fermenters were found to be at 500rpm with an airflow of 1.5 liter per mimute. Immobilization of the fungal source was found to be infeasible in natural polymers. 相似文献
2.
3.
W. S. Stark D. Schilly J. S. Christianson R. A. Bone J. T. Landrum 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1990,166(4):429-436
Summary
Drosophila rearing media had only -carotene, zeaxanthin or lutein as precursors for photopigment chromophores. Zeaxanthin and lutein are potentially optimum sources of the 3-hydroxylated retinoids of visual and accessory photopigments. Mutants made the electroretinogram in white (w) eyes selective for compound eye photoreceptors R1–6, R7 and R8: R1–6 domiantes w's electroretinogram; R7/8 generates w;ora's (ora = outer rhabdomeres absent); R8 generates w sev;- ora's (sev = sevenless). Microspectrophotometry revealed R1-6's visual pigment. In w, all 3 carotenoids yielded monotonic dose-responses for sensitivity (Fig. 4) or visual pigment (Fig. 7). An ultraviolet sensitivity peak from R1-6's sensitizing pigment was present at high but not low doses (Fig. 1). In w;ora, all 3 carotenoids gave similar spectra dominated by R7's high ultraviolet sensitivity (Fig. 2). For w sev;ora, all spectra were the shape expected for R8, peaking around 510 nm (Fig. 3). The sensitivity dose-response was at its ceiling except for low doses in w;ora (Fig. 5) and zero supplementation in w sev;ora (Fig. 6). Hence, without R1-6, most of our dose range mediated maximal visual pigment formation. In Drosophila, -carotene, zeaxanthin and lutein mediate the formation of all major photopigments in R1-6, R7 and R8.Abbreviations
ERG
electroretinogram
-
MSP
microspectrophotometry
-
HPLC
high pressure liquid chromatography
-
n.a.
numerical aperture
-
w, sev, ora Drosophila
mutants
-
y, p, r
marg types of R7 and R8 相似文献
4.
The alpha-like globin gene cluster in rabbits contains embryonic zeta-
globin genes, an adult alpha-globin gene, and theta-globin genes of
undetermined function. The basic arrangement of genes, deduced from
analysis of cloned DNA fragments, is 5'-zeta 0-zeta 1-alpha 1-theta 1- zeta
2-zeta 3-theta 2-3'. However, the pattern of restriction fragments
containing zeta- and theta-globin genes varies among individual rabbits.
Analysis of BamHI fragments of genomic DNA from 24 New Zealand white
rabbits revealed eight different patterns of fragments containing
zeta-globin genes. The large BamHI fragments containing genes zeta 0 and
zeta 1 are polymorphic in length, whereas a 1.9-kb fragment containing the
zeta 2 gene and the 3.5-kb fragment containing the zeta 3 gene do not vary
in size. In contrast to this constancy in the size of the restriction
fragments, the copy number of the zeta 2 and zeta 3 genes does vary among
different rabbits. No length polymorphism was detected in the BamHI
fragments containing the theta-globin genes, but again the copy number
varies for restriction fragments containing the theta 2 gene. The alpha 1-
and theta 1-globin genes are located in a nonpolymorphic 7.2-kb BamHI
fragment. The combined data from hybridization with both zeta and theta
probes shows that the BamHI cleavage pattern does not vary within the
region 5'-alpha 1-theta 1- zeta 2-zeta 3-theta 2-3', but the pattern
genomic blot-hybridization patterns for the progeny of parental rabbits
with different zeta-globin gene patterns shows that the polymorphic
patterns are inherited in a Mendelian fashion. Two different haplotypes
have been mapped based on the genomic blot-hybridization data. The
variation in the alpha-like globin gene cluster in the rabbit population
results both from differences in the copy number of the duplication block
containing the zeta-zeta-theta gene set and from the presence or absence of
polymorphic BamHI sites.
相似文献
5.
Christophe N. N'soukpo-Kossi Jan Sielewiesiuk Roger M. Leblanc Richard A. Bone John T. Landrum 《生物化学与生物物理学报:生物膜》1988,940(2)
The linear dichroism of single monolayers of lutein, zeaxanthin and a mixture of lutein and synthetic phosphatidylcholine has been measured. The angle of orientation of the carotenoid molecules was found to lie between 45° and 51° relative to the plane of the solid support. Although the adsorbed monolayers were mostly in a monomeric state, microscopic observations, as well as the II-A isotherms, indicated the existence of crystalline islets. The results have been interpreted in connection with Haidinger's polarization brushes. 相似文献
6.
Three white-rot fungi, Phanerochaete chrysosporium, Polyporus tulipiferae, and Polyporus sp. A336 were grown on 100-g amounts of chopped oat straw in gassed 4.5 L (diameter 16 cm, height 23 cm) solid-state reactors for two weeks. The different gas atmospheres were regulated by (1) air diffusion through foam plugs, (2) intermittent or continuous air flow, (3) intermittent oxygen, 50 or 100% continuous oxygen flow, and (4) continuous 10% carbon dioxide in oxygen flow. The fermented straw was analyzed for total weight loss, Klason lignin loss, and enzymatic (cellulase) hydrolysis. P. chrysosporium grown on straw in continuous oxygen at 35 degrees C caused a 41% weight loss and 33.5% hydrolysis was obtained when the pretreated straw was hydrolyzed with cellulase enzyme. P. tulipiferae caused a 27% weight loss and 34.3% cellulase hydrolysis in the straw at 30 degrees C. Polyporus sp. A336 selectively degraded lignin of the straw and under intermittent oxygen resulted in an 18% weight loss and 33.6% cellulase hydrolysis at 35 degrees C. When the straw was supplemented with 10% xylose (straw basis) and was continuously gassed with 50% oxygen, Polyporus sp. A336 produced a 14.5% weight loss and 38.7% cellulase hydrolysis. Oxygen and carbon dioxide exchange rates were measured for some of these bench-scale fermentations. 相似文献
7.
Nippostrongylus brasiliensis incorporated the fluorescent dye, Rhodamine B, while feeding in vivo. Uptake of dye in both sexes of helminth increased linearly from 30 to 120 min after the hosts were given dye per os. Feeding by female N. brasiliensis significantly exceeded that of the male at 4 and 5 days postinfection. Feeding declined in older helminths of both sexes. The density of helminths had no effect on their incorporation of dye in vivo. Feeding in male- and female-only groups of worms was similar to that seen in populations of mixed sexes. Feeding by helminths decreased during the first 36 h of food deprivation in the host, but increased during subsequent fasting of the host. Both sexes of N. brasiliensis resumed feeding within 15 min after the fasted hosts were fed. Growth of N. brasiliensis increased linearly from 4 to 7 days postinfection, based on dry weight. Seven-day-old and older females were significantly heavier than males. 相似文献
8.
The sporulation-specific penicillin-binding protein 5a from Bacillus subtilis is a DD-carboxypeptidase in vitro
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A chemiluminescence method for determining acetylcholinesterase activity is described. It is an adaptation of the chemiluminescence assay of acetylcholine described by Israël & Lesbats [(1981) Neurochem. Int. 3, 81-90; (1981) J. Neurochem. 37, 1475-1483]. The acetylcholinesterase activity is measured by monitoring the increase in light emission produced by the accumulation of choline or by determining the amount of choline generated after a short interval. The assay is rapid and sensitive, and uses the natural substrate of the enzyme. Kinetic data obtained with this procedure for acetylcholinesterase from Torpedo and Electrophorus electric organs were comparable with those obtained by using the method of Ellman, Courtney, Andres & Featherstone [(1961) Biochem. Pharmacol. 7, 88-95]. In addition, it was shown that sodium deoxycholate totally inactivated Torpedo acetylcholinesterase but not the Electrophorus enzyme. Competitive inhibitors of acetylcholinesterase protected the enzyme from inactivation. 相似文献
9.
Q. Bone 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1985,156(1):117-123
Summary The passive electrical properties and initiation of action potentials have been examined in the external epithelium of oikopleurid larvacean tunicates. The epithelial cells are electrically coupled, and are polygons up to 200 m across and up to 1.4–2.8 m thick. Membrane constants determined by a 2-electrode study were forO. dioica:: 922 m; Rm: 4.3 kcm2; Ri: 82.7 cm. Corresponding values for the largerO. longicauda were: 3350 m; 35.6 kcm2; and 104.5 cm. Mean resting potentials in both species were around 80 mV. Mechanical stimulation evokes over-shooting action potentials propagated (at 18 °C) at some 40 cm/s. These are rapid events, repolarisation being almost complete in 5 ms. There is no undershoot.When the recording electrode penetrates the epithelial cell from its inner surface distant mechanical stimulation may evoke similar action potentials arising from the stimulus site, but more often evokes graded small depolarisations which give rise to action potentials with increasing strength of mechanical stimulation. Reasons are given for considering these to be generator potentials resulting from deformation of the outer epithelial cell membrane by the tip of the recording electrode. The effects of epithelial action potentials upon the potentials recorded from the caudal muscle cells are briefly described. 相似文献
10.
Assignment of orthologous relationships among mammalian alpha-globin genes by examining flanking regions reveals a rapid rate of evolution 总被引:1,自引:0,他引:1
In order to study the relationships among mammalian alpha-globin genes, we
have determined the sequence of the 3' flanking region of the human alpha 1
globin gene and have made pairwise comparisons between sequenced
alpha-globin genes. The flanking regions were examined in detail because
sequence matches in these regions could be interpreted with the least
complication from the gene duplications and conversions that have occurred
frequently in mammalian alpha-like globin gene clusters. We found good
matches between the flanking regions of human alpha 1 and rabbit alpha 1,
human psi alpha 1 and goat I alpha, human alpha 2 and goat II alpha, and
horse alpha 1 and goat II alpha. These matches were used to align the
alpha-globin genes in gene clusters from different mammals. This alignment
shows that genes at equivalent positions in the gene clusters of different
mammals can be functional or nonfunctional, depending on whether they
corrected against a functional alpha-globin gene in recent evolutionary
history. The number of alpha-globin genes (including pseudogenes) appears
to differ among species, although highly divergent pseudogenes may not have
been detected in all species examined. Although matching sequences could be
found in interspecies comparisons of the flanking regions of alpha- globin
genes, these matches are not as extensive as those found in the flanking
regions of mammalian beta-like globin genes. This observation suggests that
the noncoding sequences in the mammalian alpha-globin gene clusters are
evolving at a faster rate than those in the beta-like globin gene clusters.
The proposed faster rate of evolution fits with the poor conservation of
the genetic linkage map around alpha-globin gene clusters when compared to
that of the beta-like globin gene clusters. Analysis of the 3' flanking
regions of alpha-globin genes has revealed a conserved sequence
approximately 100-150 bp 3' to the polyadenylation site; this sequence may
be involved in the expression or regulation of alpha-globin genes.
相似文献