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Characterization of a non-sedimenting membrane fraction from bovine lens
Friday, Sep 25, 1992 Palazzo Dei Congressi/A
X ICER Abstracts
LIPID CONPOSITION-STRUCTURE RETINAL ROD =RANES. m Deptartment of Ophthalmology Univiversity of Louisville,
RELATIONSHIP & Visual Louisville
IN
LENS
Sciences, KY 40292
AND U.S.A.
Every membrane has a unique lipid composition. LiDid comnosition determines livid bilaver structure which is often related to the function of the membrane. Cholesterol, sphingomyelin, and saturated hydrocarbon The membrane content of chains order lipid membranes. cholesterol, hydrocarbon chain saturation and sphingomyelin follows the order: lens nucleus > lens cortex > ROS plasma membrane > ROS disk membranes. Membrane order followed the same trend as expected by the lipid composition. Infrared spectroscopy was used to determine order in terms of lipid orderdisorder transition cooperativity, enthalpy, entropy, transition temperature and acyl chain order at 36'C. The well defined lipid structure is altered in human cataractous lens membranes where lipid oxidation and cholesterol are elevated. We found that the lipid order-disorder phase transition parameters were dramatically elevated in cataractous lens lipid membranes. For example, the cataractous lipid phase transition temperature was 4O'C, 7.8 and 14.2"C higher than the cortical and nuclear region controls respectively. These structural changes may have a profound effect on passive permeability, and ion pump activity. From these studies we can hypothesize the relationship between membrane composition, structure and function in ROS tissues that have altered lipid Supported by NIH-EY07975. composition due to disease.
CHARACTERIZATION OF A NON-SEDIMENTING MEMBRANE FRACTION FROM BOVINE LENS. Fleschner, C.R.,.Cenedella, R.J..,. Department of Biochemistry, Kirksville College of Osteopathic Medicine, Kirksville, Missouri, U.S.A. We have observed a substantial ~mo""t of lenti i pid (abuut 13X of total) which does not sediment with the membrane of the water insoluble fraction (WIF), a phenomenon independently observed by Katar, Alcala end Maisel (Invest. Oohthalmol. Vis. Sci. 2Ofsu"oll. 3&, 1981). We have characterized tjlls fraction (called th;--"-" nonsedimenti"B membrane fraction, NSMF), and compared it to the sedimentin membrane fraction (SMF) isolated from the WIF by sucrose density centrifugation. The membrane nature of the NSMF wee confirmed by electron microscopy, and the NSMF wae found proportionately distributed throughout the lens. The phospholipid composition and polypeptide compositions of both extrinsic (8 M "ree soluble) and intrinsic (8 M urea insoluble) protein of the NSHF were similar to those of the SMF. However, morphometric analysis of electron micrographs demonstrated than the NSMF contained a signiffcantly lower percentage of fiber junction membrane than did the SMF (22.8% and 41.1X, respectively). Furthermore, the relative lipid composition was substantially different: the NSMF contained e slenificantlv greater amount of total lipid measured relative to membrane protein (about 0.9 mghg protein) than did the SMF (about 0.5 mg/mg protein), and the cholesterollphoepholipid molar ratio of the NSMF (0.58) "es sianificantlv lower than that nf the SMF (0.88). We speculate that the NSMF represents 8 specialized membrane domain of fiber cells with en es yet unidentified function. Supported by NIH EYO2568.
LIPOPXOTEIX Yoshitaka Department University
IX HUMAN CATARACTOUS LENS I\! D ---AObara of Ophthalmology, Koshigaya School of Medicine, Japa"
Hospital.
Dokkyo
The lipjd composition could be responsible for chanqcs in Fearmeability and motility in cataractous lens r.embr.3n??. The cholesterol and ohosnholiuid tiahten bound with protein structure in'cataract&us lens. This study compared the quantitative changes of the lipoprotein and the a?olipoprotein which charact=rixe the nzturc of lipoprotein between diabetic cataract and senile cataract. The sampler were centrifuqed bv the density-gradient system. Chylonicron,VLDL.LDL-ano HDL rrerc identified as liuoorotein fractions. The apcllpoprotein was assay&Z by TIX methoc?. The lipoprotein value was not sionificnnt e.ifferent llretween c7iahetic crti-ract(96.95kO.96&g/lens) an? senile cataract (59.~1~1.5Yrl~'llens). In diabetic cataract, LDL and VLDL were significantly increased more than sonile cataract. BDL !xac' several specific fractions in senile cataract OP the avarocs gel electrophoresis. Apolipoprotein B,C-11 an2 C-111 which main component of LDL an? VLDL exhibiter? an evident increase in Z;iabetic cataract. They showed similar changes with the serum lipoprotein iri Dtl patient. '!e found the fluorescein labeled LDL hai? been uptalce into the hum-;: lens. It was mainly localized the epitheliun, !
s.205
X ICER Abstracts
LIPID CONPOSITION-STRUCTURE RETINAL ROD =RANES. m Deptartment of Ophthalmology Univiversity of Louisville,
RELATIONSHIP & Visual Louisville
IN
LENS
Sciences, KY 40292
AND U.S.A.
Every membrane has a unique lipid composition. LiDid comnosition determines livid bilaver structure which is often related to the function of the membrane. Cholesterol, sphingomyelin, and saturated hydrocarbon The membrane content of chains order lipid membranes. cholesterol, hydrocarbon chain saturation and sphingomyelin follows the order: lens nucleus > lens cortex > ROS plasma membrane > ROS disk membranes. Membrane order followed the same trend as expected by the lipid composition. Infrared spectroscopy was used to determine order in terms of lipid orderdisorder transition cooperativity, enthalpy, entropy, transition temperature and acyl chain order at 36'C. The well defined lipid structure is altered in human cataractous lens membranes where lipid oxidation and cholesterol are elevated. We found that the lipid order-disorder phase transition parameters were dramatically elevated in cataractous lens lipid membranes. For example, the cataractous lipid phase transition temperature was 4O'C, 7.8 and 14.2"C higher than the cortical and nuclear region controls respectively. These structural changes may have a profound effect on passive permeability, and ion pump activity. From these studies we can hypothesize the relationship between membrane composition, structure and function in ROS tissues that have altered lipid Supported by NIH-EY07975. composition due to disease.
CHARACTERIZATION OF A NON-SEDIMENTING MEMBRANE FRACTION FROM BOVINE LENS. Fleschner, C.R.,.Cenedella, R.J..,. Department of Biochemistry, Kirksville College of Osteopathic Medicine, Kirksville, Missouri, U.S.A. We have observed a substantial ~mo""t of lenti i pid (abuut 13X of total) which does not sediment with the membrane of the water insoluble fraction (WIF), a phenomenon independently observed by Katar, Alcala end Maisel (Invest. Oohthalmol. Vis. Sci. 2Ofsu"oll. 3&, 1981). We have characterized tjlls fraction (called th;--"-" nonsedimenti"B membrane fraction, NSMF), and compared it to the sedimentin membrane fraction (SMF) isolated from the WIF by sucrose density centrifugation. The membrane nature of the NSMF wee confirmed by electron microscopy, and the NSMF wae found proportionately distributed throughout the lens. The phospholipid composition and polypeptide compositions of both extrinsic (8 M "ree soluble) and intrinsic (8 M urea insoluble) protein of the NSHF were similar to those of the SMF. However, morphometric analysis of electron micrographs demonstrated than the NSMF contained a signiffcantly lower percentage of fiber junction membrane than did the SMF (22.8% and 41.1X, respectively). Furthermore, the relative lipid composition was substantially different: the NSMF contained e slenificantlv greater amount of total lipid measured relative to membrane protein (about 0.9 mghg protein) than did the SMF (about 0.5 mg/mg protein), and the cholesterollphoepholipid molar ratio of the NSMF (0.58) "es sianificantlv lower than that nf the SMF (0.88). We speculate that the NSMF represents 8 specialized membrane domain of fiber cells with en es yet unidentified function. Supported by NIH EYO2568.
LIPOPXOTEIX Yoshitaka Department University
IX HUMAN CATARACTOUS LENS I\! D ---AObara of Ophthalmology, Koshigaya School of Medicine, Japa"
Hospital.
Dokkyo
The lipjd composition could be responsible for chanqcs in Fearmeability and motility in cataractous lens r.embr.3n??. The cholesterol and ohosnholiuid tiahten bound with protein structure in'cataract&us lens. This study compared the quantitative changes of the lipoprotein and the a?olipoprotein which charact=rixe the nzturc of lipoprotein between diabetic cataract and senile cataract. The sampler were centrifuqed bv the density-gradient system. Chylonicron,VLDL.LDL-ano HDL rrerc identified as liuoorotein fractions. The apcllpoprotein was assay&Z by TIX methoc?. The lipoprotein value was not sionificnnt e.ifferent llretween c7iahetic crti-ract(96.95kO.96&g/lens) an? senile cataract (59.~1~1.5Yrl~'llens). In diabetic cataract, LDL and VLDL were significantly increased more than sonile cataract. BDL !xac' several specific fractions in senile cataract OP the avarocs gel electrophoresis. Apolipoprotein B,C-11 an2 C-111 which main component of LDL an? VLDL exhibiter? an evident increase in Z;iabetic cataract. They showed similar changes with the serum lipoprotein iri Dtl patient. '!e found the fluorescein labeled LDL hai? been uptalce into the hum-;: lens. It was mainly localized the epitheliun, !
s.205