Behaviour influences cholesterol plasma levels in a pig model

Little is known about the relationship between feed intake behaviour and cholesterol levels in humans. This can be attributed to the fact that feed intake behaviour in humans is difficult to assess. The relationships between feed intake, feed efficiency and feed intake behaviour, and cholesterol and triglyceride levels were investigated at an average age of 187 days, in a pig model consisting of 202 Duroc barrows. Feed intake and feed intake behaviour were recorded individually and daily by means of an electronic identification system. Animals with high levels of total cholesterol also had high levels of high-density lipoprotein (HDL), low-density lipoprotein (LDL) cholesterol and triglycerides. Animals with high levels of HDL also had high levels of LDL and triglycerides, and animals with high levels of LDL also had high levels of triglycerides. Animals with higher BW, higher backfat thickness, higher BW gain, higher gain of backfat deposition, higher feed intake, higher residual feed intake (RFI) and higher feed intake rate had higher levels of total, HDL and LDL plasma cholesterol. Results indicate that the relationship between feed intake and cholesterol levels is a long-term relationship, while the relationship between RFI and cholesterol levels is more of a short-term nature. The relationship between intake rate and cholesterol plasma levels disappeared after correction for the amount of feed consumed. Results indicate that feed intake independent of metabolic BW, growth and fatness, i.e. 'RFI', was positively correlated with cholesterol plasma levels. This suggests that eating food over and above the maintenance and growth requirements constitutes a health risk independent of the level of fatness.     

Great spotted cuckoo eggshell microstructure characteristics can make eggs stronger

Obligate avian brood parasites lay stronger eggs than their hosts or non‐parasitic relatives because they are rounder and have a thicker eggshell. Additionally, some other characteristics of the brood parasitic eggshells related to their microstructure such as size and orientation of calcite crystal units could also contribute to generating even stronger shells. An eggshell microstructure formed by small randomly oriented calcite crystal units can increase the robustness of the eggshells of birds. Here, the eggshell microstructure of avian brood parasites as well as their hosts have been characterized in detail, using X‐ray diffraction analyses to estimate the size and degree of orientation of calcite crystal units making the eggshell. Specifically, the brood parasitic great spotted cuckoo Clamator glandarius and two hosts (jackdaws Corvus monedula and magpie Pica pica) and one non‐host species (the pigeon, Columba livia domestica) were considered. Calcite crystal of the eggshell of the brood parasitic species was smaller and more randomly oriented than those of the eggshells of non‐parasitic species, which suggest that eggshell microstructure would contribute to explain why parasitic eggs are more resistant to breakage than those of their hosts.     

Trypsin digestion of arginase: evidence for a stable conformation manganese directed.

1. Controlled tryptic digestion of native arginase from rat liver suggests that Mn2+ promotes a stable conformation as shown by the following features. 2. An 18-fold increase in the half-life of arginase activity in the presence of Mn2+ is produced. 3. The stability of subunit B of arginase is increased in the presence of Mn2+ as revealed by SDS-PAGE during the time-course of trypsin cleavage. 4. The different digestion products of arginase with and without Mn2+ appearing during the time-course of tryptic treatment. 5. Different activity/bands protein ratio at any time of the tryptic digestion in the incubation mixtures, with and without Mn2+, are apparent.     

CCR7 expression and memory T cell diversity in humans

CCR7, along with L-selectin and LFA-1, mediates homing of T cells to secondary lymphoid organs via high endothelial venules (HEV). CCR7 has also been implicated in microenvironmental positioning of lymphocytes within secondary lymphoid organs and in return of lymphocytes and dendritic cells to the lymph after passage through nonlymphoid tissues. We have generated mAbs to human CCR7, whose specificities correlate with functional migration of lymphocyte subsets to known CCR7 ligands. We find that CCR7 is expressed on the vast majority of peripheral blood T cells, including most cells that express adhesion molecules (cutaneous lymphocyte Ag alpha(4)beta(7) integrin) required for homing to nonlymphoid tissues. A subset of CD27(neg) memory CD4 T cells from human peripheral blood is greatly enriched in the CCR7(neg) population, as well as L-selectin(neg) cells, suggesting that these cells are incapable of homing to secondary lymphoid organs. Accordingly, CD27(neg) T cells are rare within tonsil, a representative secondary lymphoid organ. All resting T cells within secondary lymphoid organs express high levels of CCR7, but many activated cells lack CCR7. CCR7 loss in activated CD4 cells accompanies CXC chemokine receptor (CXCR)5 gain, suggesting that the reciprocal expression of these two receptors may contribute to differential positioning of resting vs activated cells within the organ. Lymphocytes isolated from nonlymphoid tissues (such as skin, lung, or intestine) contain many CD27(neg) cells lacking CCR7. The ratio of CD27(neg)/CCR7(neg) cells to CD27(pos)/CCR7(pos) cells varies from tissue to tissue, and may correlate with the number of cells actively engaged in Ag recognition within a given tissue.     

Human microvascular endothelial cell prostaglandin E1 synthesis during in vitro ischemia-reperfusion

Ischemia-reperfusion injury is a microvascular event documented in numerous in vivo animal models. In animal models, prostaglandin and prostaglandin analogues have been found to ameliorate reperfusion injury. These studies were undertaken to evaluate human microvascular endothelial PGE(1) synthesis during in vitro ischemia followed by reperfusion. Human (neonatal) microvascular endothelial cell (MEC) cultures (n = 6) were subjected to sequential 2 h periods of normoxia (20% O(2)), ischemia (1.5% O(2)), and reperfusion (20% O(2)). Prostaglandin E(2) synthesis in conditioned media was determined by ELISA. Steady state levels of MEC prostaglandin H synthase (PGHS)-1 and -2 mRNA were assessed at the end of each 2-h period using RT-PCR and a quantitative mRNA ELISA. MEC PGHS protein levels were analyzed using an ELISA. PGE(1) release increased significantly during the initial 30 min of ischemia, but rapidly fell below normoxic levels by 90 and 120 min. During reperfusion, PGE(1) release returned to normoxic levels at 30, 60, and 90 min, and exceeded normoxic levels at 120 min. PGHS-1 mRNA levels were undetectable during all experimental conditions. PGHS-2 mRNA levels were unchanged by ischemia, but were decreased by reperfusion. In contrast, PGHS-2 protein levels increased 3-fold during ischemia, and remained elevated during reperfusion. Human MEC do not express PGHS-1 mRNA in vitro. Prolonged ischemia decreases MEC PGE(1) synthesis, and stimulates increased PGHS-2 protein levels without altering the steady state levels of COX-2 mRNA. During reperfusion, increased PGHS-2 protein levels persist and are associated with stimulated PGE(2) secretion, despite relative decreases in PGHS-2 mRNA.     

Chromatin organization during spermiogenesis in Octopus vulgaris. II: DNA-interacting proteins

In this article we study the proteins responsible for chromatin condensation during spermiogenesis in the cephalopod Octopus vulgaris. The DNA of ripe sperm nuclei in this species is condensed by a set of five different proteins. Four of these proteins are protamines. The main protamine (Po2), a protein of 44 amino acid residues, is extraordinarily simple (composed of only three different amino acid types: arginine (R), serine (S), and glycine (G). It is a basic molecule consisting of 79.5 mol% arginine residues. The rest of the protamines (Po3, Po4, Po5) are smaller molecules (33, 28, and 30 amino acid residues, respectively) that are homologous among themselves and probably with the main Po2 protamine. The ripe sperm nucleus of O. vulgaris also contains a small quantity of a molecule (Po1) that is similar to Po2 protamine. This protein could represent a Po2 protamine-precursor in a very advanced step of its processing. We discuss the characteristics of these proteins, as well as the relation between the complexity of chromatin condensation and the transitions of nuclear proteins during spermiogenesis in O. vulgaris.     

Inhibition of sarcoplasmic reticulum Ca2+-ATPase by miconazole

The inhibition of sarcoplasmic reticulumCa²⁺-ATPase activity by miconazole was dependent on theconcentration of ATP and membrane protein. Half-maximal inhibition wasobserved at 12 µM miconazole when the ATP concentration was 50 µMand the membrane protein was 0.05 mg/ml. When ATP was 1 mM, a lowmicromolar concentration of miconazole activated the enzyme, whereashigher concentrations inhibited it. A qualitatively similar responsewas observed when Ca²⁺ transport was measured. Likewise,the half-maximal inhibition value was higher when the membraneconcentration was raised. Phosphorylation studies carried out aftersample preequilibration in different experimental settings shed lighton key partial reactions such as Ca²⁺ binding and ATPphosphorylation. The miconazole effect on Ca²⁺-ATPaseactivity can be attributed to stabilization of theCa²⁺-free enzyme conformation giving rise to a decrease inthe rate of the Ca²⁺ binding transition. The phosphoryltransfer reaction was not affected by miconazole.