scholarly journals Action of liproprotein lipase on apoprotein-depleted chylomicrons

1978 ◽  
Vol 175 (1) ◽  
pp. 53-61 ◽  
Author(s):  
T W Lukens ◽  
J Borensztajn
Keyword(s):  
Lipoprotein Lipase ◽  
Physiological Role ◽  
Rat Plasma ◽  
High Density Lipoproteins ◽  
Complete Restoration ◽  
Immobilized Trypsin ◽  
Plasma High Density ◽  
First Time

1. Rat lymph chylomicrons were exposed to soluble and to immobilized trypsin. This treatment caused no detectable changes in the chylomicron structure or lipid composition, but did result in virtually total depletion of all their tetramethylurea-soluble apoproteins. 2. The capacity of these apoprotein-depleted chylomicrons to act as substrate for lipoprotein lipase in vitro and in situ (i.e. isolated perfused rat heart) was decreased by about 90 and 75% respectively, compared with intact chylomicrons. 3. On incubation with rat plasma high-density lipoproteins, trypsin-treated chylomicrons readily acquired a full apoprotein complement. This resulted in the complete restoration of their capacity to act as substrate for lipoprotein lipase both in vitro and in situ. 4. It is suggested that with the use of try,sin-treated chylomicrons it is now possible for the first time to investigate the physiological role that individual apoproteins play in the catabolism of triacylglycerol-rich lipoproteins by lipoprotein lipase.

scholarly journals INTEGRINS MEDIATE PLACENTAL EXTRACELLULAR VESICLE TRAFFICKING TO LUNG AND LIVER IN VIVO

2020 ◽  
Author(s):  
Sean L. Nguyen ◽  
Soo Hyun Ahn ◽  
Jacob W. Greenberg ◽  
Benjamin W. Collaer ◽  
Dalen W. Agnew ◽  
...  
Keyword(s):  
Immune Cells ◽  
Extracellular Vesicle ◽  
Dependent Manner ◽  
Cellular Phenotype ◽  
Reporter Mouse ◽  
Membrane Bound ◽  
First Time

ABSTRACTMembrane-bound extracellular vesicles (EVs) mediate intercellular communication in all organisms, and those produced by placental mammals have become increasingly recognized as significant mediators of fetal-maternal communication. Here, we aimed to identify maternal cells targeted by placental EVs and elucidate the mechanisms by which they traffic to these cells. Exogenously administered pregnancy-associated EVs traffic specifically to the lung; further, placental EVs associate with lung interstitial macrophages and liver Kupffer cells in an integrin-dependent manner. Localization of EV to maternal lungs was confirmed in unmanipulated pregnancy using a transgenic reporter mouse model, which also provided in situ and in vitro evidence that fetally-derived EVs, rarely, may cause genetic alteration of maternal cells. These results provide for the first time direct in vivo evidence for targeting of placental EVs to maternal immune cells, and further, evidence that EVs can alter cellular phenotype.

scholarly journals Anaerobic digestion is the dominant pathway for pit latrine decomposition and is limited by intrinsic factors

2019 ◽  
Vol 79 (12) ◽  
pp. 2242-2250 ◽  
Author(s):  
Miriam H. A. van Eekert ◽  
Walter T. Gibson ◽  
Belen Torondel ◽  
Faraji Abilahi ◽  
Bernard Liseki ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Oxygen Demand ◽  
In Vitro Tests ◽  
Full Potential ◽  
Water Addition ◽  
Intrinsic Factors ◽  
Pit Latrine ◽  
First Time

Abstract In vitro methods were used to assess the full potential for decomposition (measured as biogas formation) from pit latrine samples taken from the top layer of 15 Tanzanian latrines. We found considerable variability in the decomposition rate and extent. This was compared with decomposition in the same latrines, measured by comparing top layer composition with fresh stools and deeper (older) layers, to assess whether this potential was realised in situ. Results showed a close match between the extent of organic material breakdown in situ and in vitro, indicating that anaerobic digestion is the dominant pathway in latrines. The average potential decrease in chemical oxygen demand (COD) (determined as methane production in vitro within 60 days) and actual measured decrease in situ are 68.9% ± 11.3 and 69.7% ± 19.4, respectively. However in the in vitro tests, where samples were diluted in water, full decomposition was achieved in 2 months, whereas in situ it can take years; this suggests that water addition may offer a simple route to improving latrine performance. The results also allowed us to estimate, for the first time to our knowledge using experimental data, the contribution that latrines make to greenhouse gas emissions globally. This amounts to ∼2% of annual US emissions.

Operation and regulation of the lutein epoxide cycle in seedlings of Ocotea foetens

2010 ◽  
Vol 37 (9) ◽  
pp. 859 ◽  
Author(s):  
Raquel Esteban ◽  
Shizue Matsubara ◽  
María Soledad Jiménez ◽  
Domingo Morales ◽  
Patricia Brito ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Higher Plants ◽  
Daily Basis ◽  
Field Conditions ◽  
Photochemical Quenching ◽  
Complete Restoration ◽  
Non Photochemical Quenching ◽  
First Time

Two xanthophyll cycles are present in higher plants: the ubiquitous violaxanthin (V) cycle and the taxonomically restricted lutein epoxide (Lx) cycle. Conversions of V to zeaxanthin (Z) in the first and Lx to lutein (L) in the second happen in parallel under illumination. Unlike the V cycle, in which full epoxidation is completed overnight, in the Lx cycle, this reaction has been described as irreversible on a daily basis in most species (the ‘truncated’ Lx cycle). However, there are some species that display complete restoration of Lx overnight (‘true’ Lx cycle). So far, little is known about the physiological meaning of these two versions of the Lx cycle. Therefore, in the present work, the ‘true’ Lx cycle operation was studied in seedlings of Ocotea foetens (Aiton) Benth. under controlled and field conditions. Complete overnight recovery of the Lx pool in the presence of norfluorazon suggested that the inter-conversions between Lx and L represent a true cycle in this species. Furthermore, Lx responded dynamically to environmental conditions during long-term acclimation. Our data demonstrate the operation of a ‘true’ Lx cycle and, for the first time, its potential involvement in the regulation of non-photochemical quenching in situ. We propose dual regulation of Lx cycle in O. foetens, in which the extent of Lx restoration depends on the intensity and duration of illumination.

Frequency-force relationships of mammalian ventricular muscle in vivo and in vitro

1976 ◽  
Vol 230 (3) ◽  
pp. 631-636 ◽  
Author(s):  
ML Kahn ◽  
F Kavaler ◽  
VJ Fisher
Keyword(s):  
Heart Rate ◽  
Left Ventricle ◽  
Room Temperature ◽  
Physiological Role ◽  
Ventricular Muscle ◽  
Contractile State ◽  
Force Relationship

The change in contractility with increasing heart rate was studied in the left ventricle of dogs and in isolated trabeculae carneae of cats. For some of the studies in situ a transient isovolumic state was created by aortic occlusion. At physiological temperatures the frequency-force relationship is flatter than at room temperature and at the same temperature it is flatter in vivo than in vitro. The frequency-(dF/dt)max relationship is steeper than the frequency-force relationship at both temperatures in vivo and in vitro. The frequency-(dF/dt)max relationship is steeper in vitro than it is in situ, although the discrepancy is less marked than in the case of the frequency-force relationship. It is concluded that "staircase" plays less of a physiological role in adjustment of contractile state in situ than might be inferred from studies of isolated tissue.

scholarly journals Hydrolysis of plasma triacylglycerol-rich lipoproteins from immature and laying hens (Gallus domesticus) by lipoprotein lipase in vitro

1982 ◽  
Vol 206 (3) ◽  
pp. 647-654 ◽  
Author(s):  
H Griffin ◽  
G Grant ◽  
M Perry
Keyword(s):  
Lipoprotein Lipase ◽  
Lipid Composition ◽  
Laying Hens ◽  
Laying Hen ◽  
Dietary Lipid ◽  
Gallus Domesticus ◽  
High Density Lipoproteins ◽  
Plasma Triacylglycerol ◽  
Hydrolysis Of

Very-low-density (VLD) lipoproteins and portomicrons were isolated from the plasma of immature and laying hens and their size, lipid composition and susceptibility to hydrolysis by lipoprotein lipase were compared. In agreement with other studies, VLD lipoproteins from laying hens were found to be smaller and have a different lipid composition than VLD lipoproteins from immature hens. Portomicrons from immature and laying hens had mean diameters of about 150 nm and similar lipid compositions. Hydrolysis of VLD lipoproteins from immature hens, and portomicrons from immature and laying hens, proceeded rapidly until at least 40% of the substrate had been used. In contrast only 1-15% of laying-hen VLD-lipoprotein triacylglycerol was readily hydrolysis occurred slowly. The limited susceptibility of laying-hen VLD lipoproteins appeared to be due to their low content of lipoprotein lipase activator apoprotein, which occurred despite an abundance of activator in the high-density lipoproteins of laying-hen plasma. The results provide further evidence that the liver of the laying hen synthesizes specialized lipoproteins. Their limited susceptibility to hydrolysis by lipoprotein lipase is probably a major factor in ensuring transport of lipid to yolk rather than to other tissues. The form of transport of dietary lipid, however, is similar in immature and laying hens.

Norethindrone alters apolipoprotein e concentration and isoform expression in rat plasma high-density lipoproteins

Life Sciences ◽  
1993 ◽  
Vol 53 (4) ◽  
pp. PL51-PL55 ◽  
Author(s):  
Anne Valette ◽  
Laurence Mercier ◽  
Alain Vérine ◽  
Claude Delpéro ◽  
Jean Boyer
Keyword(s):  
Apolipoprotein E ◽  
Rat Plasma ◽  
High Density ◽  
High Density Lipoproteins ◽  
Plasma High Density ◽  
Isoform Expression

scholarly journals Glycodelin mRNA is expressed in the genital tract of male and female rats (Rattus norvegicus)

1999 ◽  
Vol 23 (1) ◽  
pp. 57-66 ◽  
Author(s):  
C Keil ◽  
B Husen ◽  
J Giebel ◽  
G Rune ◽  
R Walther
Keyword(s):  
Epithelial Cells ◽  
Reproductive Tract ◽  
In Situ Hybridisation ◽  
Physiological Role ◽  
Reproductive Organs ◽  
Female Rats ◽  
Male And Female Rats ◽  
First Time

In the present study we demonstrate for the first time the expression of glycodelin mRNA in the female and male genital tracts of rats using non-radioactive in situ hybridisation. Glycodelin fragment 1 (+41 to +141) shares 100% homology with the human gene sequence. In the ovary, glycodelin mRNA was restricted to granulosa cells. In the uterus, glycodelin mRNA was expressed in all epithelial cells of the endometrium. In the male reproductive tract, glycodelin mRNA was distributed in all epithelial cells of the epididymis, the prostate and the seminal vesicle. However, in the testis, glycodelin mRNA was predominantly found in spermatogonia and in spermatocytes of the seminiferous epithelium. The expression in several reproductive organs of rats offers an excellent tool to study further the physiological role of glycodelin, which is so far thought to act as an immunosuppressive factor.

scholarly journals Effects of C apoproteins on the activity of endothelium-bound lipoprotein lipase

1978 ◽  
Vol 175 (3) ◽  
pp. 1143-1146 ◽  
Author(s):  
T W Lukens ◽  
J Borensztajn
Keyword(s):  
Lipoprotein Lipase ◽  
Rat Heart ◽  
Perfused Rat Heart ◽  
Hydrolysis Of

Rat apoprotein C-II activated the hydrolysis of triacylglycerol in apoprotein-depleted chylomicrons by lipoprotein lipase in vitro and in the perfused rat heart. Apoproteins C-I and C-III-3 inhibited the hydrolysis of the triacylglycerol moiety in intact and apoprotein C-II-re-activated chylomicrons in vitro, but had no effect on the hydrolysis in situ.

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