Is the Fatty Acid Composition of Phospholipids Important for the Function of the Circadian Clock in Neurospora crassa?

Effects of pheriylmethanol (PM), 2-phenylethanol (PE) and 3-phenyl-1-propanol(PP) on the conidiation rhythm and on the fatty acid compositionof phospholipids were examined in Neurospora crassa. The periodfor the conidiation rhythm was shortened in proportion to theconcentration used of PE of more than 1 mM. PM at 10 mM andPP at 3 mM, however, did not cause a decrease in the lengthof the period. PE did not affect the temperature compensationof the length of the period or the amplitude of the phase shiftby light. The ratio of linolenic acid to Hnoleic acid decreased in proportionto the concentrations of PE, PM, and PP in all the phospholipidsexamined. The proportion of phosphatidic acid+diphosphatidylglycerolto the total phospholipids also was decreased by these compounds.Period shortening by PE can not be explained by the change inthe phospholipid fatty acid composition. (Received April 18, 1983; Accepted June 22, 1983)     

Carbachol-Induced Cosecretion of Immunoreactive Atrial Natriuretic Peptides with Catecholamines from Cultured Bovine Adrenal Medullary Cells

The distribution and secretion of atrial natriuretic peptides (ANPs) were investigated in bovine adrenal medulla. (1) Cultured bovine adrenal medullary cells (2 x 10(6)/dish) contained 100.4 +/- 6.0 fmol of immunoreactive ANP (IR-ANP) and 207.3 +/- 6.6 nmol of catecholamines as epinephrine plus norepinephrine. (2) Stimulation of nicotinic but not muscarinic acetylcholine receptors caused a cosecretion of IR-ANP and catecholamines corresponding to the ratio of IR-ANP to catecholamines in cultured bovine adrenal medullary cells. (3) Carbachol-stimulated secretion of IR-ANP was dependent on the presence of extracellular Ca2+. (4) Chromaffin granules isolated from bovine adrenal medulla contained large amounts of IR-ANP and catecholamines, in the same ratio as did cultured adrenal medullary cells. (5) Reverse-phase HPLC analysis showed that both stored and secreted IR-ANP consisted of two components, which eluted at the position of ANP(99-126) or ANP(1-126). These results indicate that ANPs are stored as ANP(99-126) and ANP(1-126) in chromaffin granules, and are cosecreted in parallel with catecholamines in a Ca2+-dependent manner by the stimulation of nicotinic acetylcholine receptors.     

Impairment of Mobility in Endodermal Cells by FAK Deficiency

Focal adhesion kinase (FAK) is a novel nonreceptor protein tyrosine kinase that localizes in focal adhesions. It is expressed in a variety of cell types, and we reported earlier that its deficiency causes a decrease of mobility in mesodermal cells with enhanced formation of focal adhesions. With embryoid bodies generated from embryonic stem cells, we also observed a decrease of mobility in FAK-deficient endodermal cells with enhanced focal adhesion formation.     

Peroxyoxalate chemiluminescent assay for oxidase activities based on detecting enzymatically formed hydrogen peroxide

A sensitive peroxyoxalate chemiluminescent (PO-CL) assay for activities of oxidases (uricase, choline oxidase, cholesterol oxidase and xanthine oxidase) which catalyse a formation of hydrogen peroxide was developed using 4,4′-oxalyl-bis[(trifluoromethylsulphonyl)imino]trimethylene-bis(4-methylmorpholinium)trifluoromethanesulphonate as a chemiluminogenic reagent and 2,4,6,8-tetramorpholinopyrimido[5,4-d]pyrimidine as a fluorophore. The standard curve for hydrogen peroxide was linear over the range 1 × 10^?7-1 × 10^?4 mol/L. Relative standard deviations for oxidase assays were 5.1–12.7% (n = 10). Detection limits were 1 × 10^?3 U/mL for uricase, 5 × 10^?4 U/mL for choline oxidase, 5 × 10^?3 U/mL for cholesterol oxidase and 5 × 10^?4 U/mL xanthine oxidase (sample to blank ratio, 3).     

Interleukin-5 induces tumor suppression by peritoneal exudate cells in mice

The antitumor activity of peritoneal exudate cells (PEC) induced by murine interleukin-5 (mIL-5) was examined using Meth-A sarcoma cells transplanted into the peritoneal cavity of mice. Although in vitro treatment of Meth-A sarcoma cells with mIL-5 did not result in inhibition of their growth, treatment of mice intraperitoneally with mIL-5 (1 g/day) from day –5 to +5 (tumor cells were inoculated on day 0) led to a significant increase in survival or even rejection of tumor cells. This antitumor effect depended on the dose of mIL-5. Interestingly, there was identical therapeutic activity when the protocol of days –10 to –1 was used as opposed to –5 to +5. In addition, post-treatment with mIL-5 from day +1 to +10 was ineffective. This suggests that the therapeutic activity of IL-5 is largely prophylactic. Under the former condition, the number of PEC was found to increase over 50-fold when compared to levels in control mice. Moreover, the antitumor effect of mIL-5 was completely abolished by subcutaneous injection of anti-mIL-5 monoclonal antibodies. The treatment of mice injected intraperitoneally with human IL-2 also resulted in an increase in survival. Winn assay experiments using PEC recovered from mIL-5-treated mice (1g/day, from day –10 to –1) revealed that these PEC could mediate antitumor activity against Meth-A sarcoma cells. Furthermore, when the cured mice were re-injected with Meth-A sarcoma cells or syngeneic MOPC 104E cells, they could reject Meth-A sarcoma cells but not MOPC 104E cells, indicating that immune memory had been generated. These results suggest that IL-5 augumented the PEC tumoricidal activity but we have no indication that the tumoricidal activity was mediated through a mIL-5-dependent mechanism.     

Signal transduction between the two regulatory components involved in the regulation of the kdpABC operon in Escherichia coli: Phosphorylation-dependent functioning of the positive regulator, KdpE

The proteins KdpD and KdpE are crucial to the osmotic regulation of the kdpABC operon that is responsible for the high-affinity K⁺ ion transport system in Escherichia coli. We demonstrated previously that the response regulator, KdpE, is capable of undergoing Phosphorylation mediated by the sensory protein kinase, KdpD. In this study, we obtained biochemical evidence supporting the view that when KdpE is phosphorylated, it takes on an active form that exhibits relatively high affinity for the kdpABC promoter, which in turn results in activation of the kdpABC operon. It was also suggested that the central hydrophobic domain of KdpD, which is conceivably responsible for membrane anchoring of this protein, plays a role in the signalling mechanism underlying KdpE Phosphorylation in response to hyperosmotic stress.