- chapter and author info
- Progress in Lipid Research
- Advances in Lipid Research, Volume 16
- Biochemistry of lipids in plant cell cultures | SpringerLink
There is a body of evidence that therapies effective against plasma HDL-cholesterol and triglycerides are associated with a strong reduction of cardiovascular risk; in addition, hypolipidemic treatment is able to increase LDL particle size and this increment correlates with regression of coronary stenosis. Recently, the Coordinating Committee of the National Cholesterol Education Program suggested that very high-risk patients may benefit from stronger lipid-lowering measures, a category of individuals that includes those with the atherogenic lipoprotein phenotype.
Since the therapeutical modulation of each of the three components of the lipid triad is associated with a strong reduction in the risk of cardiovascular events, LDL size measurement may be extended as much as possible to patients at high risk of cardiovascular diseases. The Journal of Japan Atherosclerosis Society. Already have an account?
Login in here. Journal of Atherosclerosis and Thrombosis. Browse All Figures Return to Figure. Previous Figure Next Figure. Email or Customer ID. Forgot password?
chapter and author info
Old Password. New Password. Password Changed Successfully Your password has been changed. Returning user. Request Username Can't sign in? Forgot your username? TEX 86 L values were calculated according to Kim et al.
TEX 86 L values were converted into temperatures using the following equation Kim et al. BIT, an index of relative contribution of terrestrial versus marine input, was calculated according to Hopmans et al. MI, the methane index indicating the relative contribution of GDGTs derived from methanotrophic Archaea to those from planktonic Thaumarchaeota, was calculated as follows Zhang et al.
RI, the ring index, is a tool for identifying a potential nonthermal influence on GDGT distributions. A sample's ring index is defined as follows Zhang et al.
The satellite-derived SSTs were averaged over the collection period of each sample cup. The depth profiles of mean annual water temperature and nitrate concentration were obtained from the World Ocean Atlas WOA13 representing averaged values for the years — Garcia et al. Lithogenic flux is presented separately in Fig. The composition of sinking particles changed between seasons.
GDGT fluxes varied between 7. The flux-weighted mean TEX 86 L temperature during the trap deployment period was 2. Estimated temperatures calculated using the calibrations as described in Eqs. The last two data points for the trap time series were unusually low when using Eq. The purple and orange lines indicate the calculated temperatures using the calibrations by Fietz et al.
The green line indicates the TEX 86 L -derived temperatures. The mass flux data of the PF3 trap have been published previously by Fischer et al. The mass flux at the shallow trap ranged between At the deep trap, the mass flux varied between 0 and There was no clear correlation between organic material and GDGT fluxes at either depth.
The fluxes in GDGTs ranged from GDGT fluxes were mostly enhanced during the low-mass-flux season at the shallow trap Fig. The TEX 86 L -derived temperatures ranged between 1. The flux-weighted mean TEX 86 L temperatures were 4. In some samples, GDGT—3 was below the detection limit. Most samples did not exceed the index values indicating nonthermal impacts on TEX 86 see Sect. Estimated temperatures calculated according to Eqs. With the same calibrations, estimated temperatures varied between 3.
The green lines indicate the TEX 86 L -derived temperatures. For instance, aggregates formed from coccolithophores are ballasted by carbonate and may sink faster than opal-ballasted diatom aggregates Iversen and Ploug, Still, fecal pellets formed from either coccolithophores or diatoms sink faster than fecal pellets formed from non-ballasted flagellates Ploug et al.
GDGTs have been suggested to be preferentially incorporated into opal-dominated particles Mollenhauer et al. Those two episodic GDGT pulses occurred when carbonate, coccolithophore, and terrestrial biomarker fluxes were enhanced, potentially resulting in the enhanced GDGT flux Chen et al.
Progress in Lipid Research
This agrees with the concept that GDGTs are transported by particles mainly containing opal and carbonate as previously shown in sediment trap studies Chen et al. This observation suggests that GDGTs are exported together with diatoms opal and coccolithophores carbonate. Supporting this, diatom and coccolithophore fluxes both, previously reported by Lalande et al. We thus assume that terrestrial material is aggregated into particles which carry GDGTs.
Advances in Lipid Research, Volume 16
The lithogenic material seems to be mainly supplied by downslope export from the nearby Svalbard archipelago Lalande et al. GDGTs might also be exported with fecal pellets after grazing of Archaea by zooplankton. Indeed, GDGTs have been found in decapod guts and intestines, and their abundance ratios appear to be unaltered during gut passage Huguet et al.
The fecal pellet carbon FPC flux from appendicularians contributed more to the total carbon flux than copepod FPC flux.
Both appendicularian and copepod FPC fluxes were higher during spring than during summer Fig. Overall, it is reasonable to assume that seasonal changes in the relative proportion of materials that GDGTs can be aggregated with may result in variable export velocities of particles carrying GDGTs to deeper waters in the eastern Fram Strait. Although it did not display a clear seasonality, the TEX 86 L signal is most likely to reflect the surface water environments without nonthermal effects influencing the TEX 86 L Fig. Secondly, the index values e. The BIT index defined by Hopmans et al.
MI Zhang et al. Both index values were consistently lower than the respective critical values of 0. Lastly, although significant portions of particles transported to the mid-depth and deep water in the eastern Fram Strait originated off Svalbard and the Barents Sea Lalande et al.
Therefore, we conclude that GDGTs are mainly transported from upper waters and non-regional sources of particles do not play a significant role in the TEX 86 L estimate of sinking particles of the eastern Fram Strait. This is the most productive period in the Fram Strait and also the period with the highest export fluxes e. The material collected by deep-ocean sediment traps is a mixture of many types of aggregates with different composition and settling velocities.
Biochemistry of lipids in plant cell cultures | SpringerLink
Therefore, fluctuating TEX 86 L temperatures might be due to an average of signals from previous before mid-July, i. Due to the collection of aggregates sinking with different velocities, one sample cup in a sediment trap may collect GDGTs of different ages. These signals might be derived from GDGTs synthesized in mid-August to October, which was a late-bloom period dominated by protists that do not produce biominerals, such as Phaeocystis sp.
Aggregates formed without biominerals have low sinking velocities Iversen and Ploug, ; Ploug et al. It shows that the bias of the calibration occurs neither in one direction only nor to the same extent even at a given location; instead the temperature estimate is more affected by other processes discussed above. Eddies around the ice edge create upwelling and downwelling, which breaks the stratified surface water and supplies nutrients to the upper water column, fostering phytoplankton blooms Lalande et al. The sea ice-edge bloom probably enhanced the GDGT production followed by zooplankton grazing.