Photoperiod- and temperature-dependent regulation of pupal beige/black polymorphism in the small copper butterfly, Lycaena phlaeas daimio Seitz

The small copper butterfly, Lycaena phlaeas daimio, has pupal beige/black polymorphism, the development of which is found to be controlled in an apparent association with the development of adult seasonal polymorphism (spring and summer morphs) by photoperiod and temperature in the larval stages. That is, the pupae of beige and black types developed under long-day and short-day conditions tend to develop into brown-winged and red-winged adults, respectively. In addition, a large proportion of long-day pharate pupae chilled at 4 degrees C for 5 days were observed to develop into pupae whose head-thoracic complexes and abdomens were judged to be of the black and intermediate types, respectively. They developed into adults with redder wings as compared to those obtained from unchilled pupae. The results indicate that the physiological mechanism underlying the photoperiodic control of the development of adult seasonal polymorphism may also play a significant role in the determination of pupal beige/black polymorphism in L. phlaeas daimio. Furthermore, cuticle melanization was found to be induced in the head-thoracic complexes of pupae by chilling of the pharate pupae. Melanization of pupal cuticle seems to occur in a close association with the development of reddish-winged adults.     

Presence of anionic phospholipids rules the membrane localization of phenothiazine type multidrug resistance modulator

Substances able to modulate multidrug resistance (MDR), including antipsychotic phenothiazine derivatives, are mainly cationic amphiphiles. The molecular mechanism of their action can involve interactions with transporter proteins as well as with membrane lipids. The interactions between anionic phospholipids and MDR modulators can be crucial for their action. In present work we study interactions of 2-trifluoromethyl-10-(4-[methanesulfonylamid]buthyl)-phenothiazine (FPhMS) with neutral (PC) and anionic lipids (PG and PS). Using microcalorimetry, steady-state and time-resolved fluorescence spectroscopy we show that FPhMS interacts with all lipids studied and drug location in membrane depends on lipid type. The electrostatic attraction between drug and lipid headgroups presumably keeps phenothiazine derivative molecules closer to surface of negatively charged membranes with respect to neutral ones. FPhMS effects on bilayer properties are not proportional to phosphatidylserine content in lipid mixtures. Behavior of equimolar PC:PS mixtures is similar to pure PS bilayers, while 2:1 or 1:2 (mole:mole) PC:PS mixtures resemble pure PC ones.     

Neuronal nitric oxide synthase (NNOS) catalyzes one-electron reduction of 2,4,6-trinitrotoluene, resulting in decreased nitric oxide production and increased nNOS gene expression: implication for oxidative stress

To determine the mechanism of 2,4,6-trinitrotoluene (TNT)-induced oxidative stress involving neuronal nitric oxide synthase (nNOS), we examined alterations in enzyme activity and gene expression of nNOS by TNT, with an enzyme preparation and rat cerebellum primary neuronal cells. TNT inhibited nitric oxide formation (IC(50) = 12.4 microM) as evaluated by citrulline formation in a 20,000 g cerebellar supernatant preparation. A kinetic study revealed that TNT was a competitive inhibitor with respect to NADPH and a noncompetitive inhibitor with respect to L-arginine. It was found that purified nNOS was capable of reducing TNT, with a specific activity of 3900 nmol of NADPH oxidized/mg/min, but this reaction required CaCl(2)/calmodulin (CaM). An electron spin resonance (ESR) study indicated that superoxide (O(2)(.-)) was generated during reduction of TNT by nNOS. Exposure of rat cerebellum primary neuronal cells to TNT (25 microM) caused an intracellular generation of H(2)O(2), accompanied by a significant increase in nNOS mRNA levels. These results indicate that CaM-dependent one-electron reduction of TNT is catalyzed by nNOS, leading to a reduction in NO formation and generation of H(2)O(2) derived from O(2)(.-). Thus, it is suggested that upregulation of nNOS may represent an acute adaptation to an increase in oxidative stress during exposure to TNT.     

Accumulation of calcium and phosphorus accompanied by inevitable accumulation of magnesium in human arteries

To examine whether there were differences between races in regard to the relationships among element contents in the arteries, the authors investigated the relationships among the average contents of calcium, phosphorus, sulfur, and magnesium in the 18 kinds of the Thai artery. After ordinary dissection by medical students at Chiang Mai University was finished, the thoracic and abdominal aortas, ramifying site of the abdominal aorta into the common iliac arteries, coronary, common carotid, internal thoracic, subclavian, axillary, brachial, radial, superior and inferior mesenteric, renal, common iliac, internal iliac, and external iliac arteries were resected from the subjects who consisted of 12 men and 3 women, ranging in age from 39 to 84 yr. The femoral and posterior tibial arteries were resected from the subjects, consisting of 15 men and 5 women, ranging in age from 25 to 88 yr. The element content of the arteries was analyzed by inductively coupled plasma-atomic emission spectrometry. It was found that there were extremely significant direct correlations among the average contents of calcium, phosphorus, and magnesium in the 18 kinds of the Thai artery, but no significant correlations were found between the average contents of sulfur and elements, such as calcium, phosphorus, and magnesium. These results were in agreement with those of the Japanese arteries. Therefore, it was suggested that there was no significant difference between the arteries of the Thai and the Japanese in the relationships among calcium, phosphorus, sulfur, and magnesium.     

Age-related changes of elements and relationships among elements in the common bile and pancreatic ducts

To elucidate compositional changes of the common bile and main pancreatic ducts with aging, the authors investigated age-related changes of element contents in the common bile and pancreatic ducts by inductively coupled plasma-atomic emission spectrometry. After ordinary dissection by medical students was finished, the common bile ducts and main pancreatic ducts (pancreatic ducts) were resected and the element contents were determined. The Mg content increased significantly only in the pancreatic duct with aging, but the other element contents did not change significantly in both the common bile and pancreatic ducts with aging. Regarding the relationship among the elements, significant direct correlations were found among the contents of Ca, P, S, and Mg in the common bile ducts, with some exceptions between P and either S or Mg contents. In the pancreatic ducts, significant direct correlations were found between S and Mg contents and between P and Na contents. The relationships in the elements between the common bile and pancreatic ducts were examined. It was found that there were significant direct correlations in the Ca, Mg, and Fe contents between the common bile and pancreatic ducts; that is, as Ca, Mg, and Fe increased in the common bile duct, they increased simultaneously in the pancreatic duct.     

Long-lasting smooth-muscle relaxation by a novel PACAP analogue in human bronchi

We compared the relaxant effect of original pituitary adenylate cyclase-activating peptide (PACAP)1-27 with that of a newly developed, synthetic PACAP1-27 analogue, [Arg15,20,21 Leu17]-PACAP-Gly-Lys-Arg-NH2, in human bronchi in vitro (n=4-5 in each group). Using precontraction by carbachol (0.1 microM), cumulative administration of PACAP1-27 and salbutamol caused concentration-dependent smooth muscle relaxation with similar potencies and maximum relaxant effects. Non-cumulative administration of the PACAP1-27 analogue and the original PACAP1-27 caused concentration-dependent relaxation with a similar maximum relaxant effect and potency as well. However, the onset and offset of action was markedly slower for the PACAP1-27 analogue than for the original PACAP1-27 (>90% versus <10% of peak relaxation remaining 5 h after administration). Peptidase inhibition by captopril (10 microM) and phosphoramidon (1 microM) significantly increased the maximum relaxant effect and duration of action of PACAP1-27 but not of the PACAP1-27 analogue, during the 3 h of observation in the human bronchi. We conclude that [Arg15,20,21 Leu17]-PACAP-Gly-Lys-Arg-NH2 produces significant concentration-dependent and sustained bronchial smooth muscle relaxation in vitro. The sustained relaxant effect is due, at least in part, to the synthetic PACAP1-27 analogue being less susceptible to cleavage by peptidases than the original peptide PACAP1-27.     

Solution properties of gellan gum: change in chain stiffness between single- and double-stranded chains

Nine samples of gellan gum in the sodium form, ranging in weight-average molar mass from 3.47 x 10(4) to 1.15 x 10(5) at 40 degrees C, were investigated by static and dynamic light scattering and viscometry in 25 mM aqueous NaCl both at 40 and at 25 degrees C. The ratios of the molar mass at 25 degrees C (in the ordered state) to that at 40 degrees C (in the disordered state) were in the range of 1.99 to 2.07, supporting the scheme of the conformational transition of gellan gum between a disassociated single chain and an associated chain composed of two molecules. Focusing on the effects of polydispersity, the intrinsic viscosities, radii of gyration, and hydrodynamic radii were analyzed on the basis of unperturbed wormlike chain models. The persistence lengths were evaluated as 9.4 nm at 40 degrees C and 98 nm at 25 degrees C.     

IkappaB kinases: key regulators of the NF-kappaB pathway

The nuclear factor (NF)-kappaB pathway is important for the expression of a wide variety of genes that are involved in the control of the host immune and inflammatory response, and in the regulation of cellular proliferation and survival. The constitutive activation of this pathway is associated with inflammatory and autoimmune diseases, such as asthma, rheumatoid arthritis and inflammatory bowel disease, in addition to atherosclerosis, Alzheimer's disease, cancer and diabetes. One of the key steps in activating the NF-kappaB pathway is the stimulation of the IkappaB (inhibitor of kappaB) kinases. Recent data indicate that these kinases activate the NF-kappaB pathway through distinct steps that are operative in both the cytoplasm and the nucleus. A better understanding of the mechanisms that activate this pathway provides the potential for defining new therapeutic targets that might prevent the aberrant activation of NF-kappaB in a variety of human diseases.     

Guanylyl cyclase and cGMP-specific phosphodiesterase participate in the acrosome reaction of starfish sperm

In the starfish, Asterias amurensis, the cooperation of three components of the egg jelly, i.e. ARIS (acrosome reaction-inducing substance), Co-ARIS and asterosap, is responsible for inducing the acrosome reaction. Experimentally, ARIS and asterosap are sufficient for the induction. However, when sperm are treated only with asterosap, they become unresponsive to the egg jelly to undergo the reaction. In this study, we analysed the mechanism of the acrosome reaction, using sperm inactivation by asterosap as a clue. Asterosap causes a rapid and transient increase in intracellular cGMP through the activation of the asterosap receptor, a guanylyl cyclase, and causes an increase in intracellular Ca(2+). When sperm were pretreated with asterosap, the guanylyl cyclase seemed to be inactivated irreversibly by dephosphorylation. They were still responsive to ARIS but no longer to asterosap. However, in the presence of IBMX or zaprinast, inhibitors against phosphodiesterases (PDEs), they retained their capacity to undergo the acrosome reaction in response to the egg jelly or ARIS alone. IBMX and zaprinast suppressed the intracellular catabolism of cGMP, but not of cAMP. These results suggest that guanylyl cyclase and cGMP-specific, IBMX- and zaprinast-susceptible PDEs are involved in the regulation of the acrosome reaction.