Flow microcalorimetry investigation of the influence of surfactants on a heterogeneous aerobic culture

The influence of various surfactants on the biological activity of a mixed aerobic culture has been investigated by using flow microcalorimetry. The response of the culture to the addition of homologous n-alkylcarboxylates (C2 to C16) and n-alkylpyridinium bromides (C11 to C14) has been examined under endogenous and substrate saturation conditions, and inhibitory concentrations (MIC or the concentration which decreased the initial activity (heat flux) of the culture by 50%) were determined for each state. Under both conditions, the n-alkylpyridinium bromides were found to be more toxic than the n-alkylcarboxylates of identical chain length, thus confirming that the head group of the amphiphiles plays an important role in the microbial toxicity of surfactants. The relationship observed between the concentration at which 50% of the activity is lost and the chain length of the surfactant further confirms that cellular toxicity is also dependent on surfactant hydrophobicity. In relation to the biodegradability of surfactants in mixed aerobic cultures, the low concentration effects of n-alkylcarboxylates on endogenous culture were investigated in some detail. There appear to be compounded indications that these surfactants are rapidly metabolized by the microorganisms of the mixed culture, at least for homologs lower than C10.     

Quantitation and immunohistochemical localization of cathepsins E and D in rat tissues and blood cells

The distribution of cathepsins E and D in various rat tissues and blood cells was determined by immunoprecipitation and by immunohistochemistry with discriminative antibodies specific for each enzyme. While cathepsin D was detected in all of the tissues and blood cells tested (except for erythrocytes), cathepsin E had a relatively limited distribution. The cathepsin E content was highest in the stomach and was succeeded in the following order by the urinary bladder, thymus, spleen, cervical lymph node and bone marrow. Significant amounts of cathepsin E were also found in the colon, rectum, jejunum, skin, lung, kidney and submandibular gland. The other tissues tested had little or no detectable cathepsin E content. Of the blood cells tested, lymphocytes and peritoneal neutrophils contained high levels of cathepsin E. Erythrocytes had cathepsin E only as aspartic proteinases. When the subcellular localization of cathepsin E in the neutrophils was investigated by fractionation of the postnuclear supernatants, the enzyme behaved as a soluble cytosolic enzyme. In contrast, cathepsin D was mainly associated with the granular fraction. The immunohistochemical localization of cathepsins E and D was clearly different in the stomach, large intestines, kidney and urinary bladder, but was similar in the lymph node and spleen. The tissue-fixed macrophages, which were notable in the skeletal and cardiac muscle tissues, submucosal layers of the gastrointestinal tracts, salivary gland, lung and trachea, also exhibited similar intense immunoreactivities demonstrative of both cathepsins E and D.     

Antibody against 25,000 dalton tryptic fragment of subfragment-1 from chicken skeletal muscle myosin: functional implication of the 25,000 fragment region in subfragment-1

Antibody was prepared against the 25,000-dalton tryptic fragment of subfragment-1 from skeletal muscle myosin. The antibody was found to inhibit the Mg2+-ATPase activity and the initial P1-burst of the ATPase. The antibody suppressed the ATP-induced fluorescence enhancement of S-1, though it did not suppress the binding of ATP to S-1. The acto-S-1 ATPase activity was also inhibited by the antibody. These results suggest that there is a site in the 25K fragment region responsible for the transition of the myosin-ATP complex to another high energy complex.     

Remodeling of Human Sperm Chromatin Mediated by Nucleoplasmin from Amphibian Eggs

The molecular events associated with decondensation of human sperm nuclei were analyzed by incubating sperm with egg extracts from an amphibian, Bufo japonicus . Acid-urea-Triton polyacrylamide gel electrophoresis (AUT-PAGE) showed that the nuclear basic proteins of human sperm consist mainly of protamines (HPI, HPII) with minor amounts of nucleosomal histones. On incubation of lysolecithin (LC)- and dithiothreitol (DTT)-treated human sperm with the egg extract, the nuclei lost HPI and HPII within 15 min in association with extensive nuclear decondensation, and the acquirement of a whole set of nucleosomal histones. Incubation of LC-DTT-sperm with nucleoplasmin purified from Bufo eggs also induced nuclear decondensation and loss of protamines within 30 min. Native-PAGE and Western blot analyses of incubation medium indicated tight association of the released protamines to nucleoplasmin, strongly suggesting that protamines are removed from sperm nuclei not enzymatically but by their specific binding to nucleoplasmin. On incubation of LC-DTT-sperm with nucleoplasmin and exogenous nucleosomal core histones, micrococcal nuclease-protected DNA fragments were released, although their unit repeat length was slightly less than that of somatic nucleosomes. Thus remodeling of human sperm during fertilization can be mimicked under defined conditions with nucleoplasmin and exogenous histones.     

Immunological Studies of Betaine Aldehyde Dehydrogenase in Barley

The changes in the level of the protein for betaine aldehydedehydrogenase, which catalyzes the last step in the synthesisof glycinebetaine, were analyzed with antiserum raised againstSDS-denatured betaine aldehyde dehydrogenase from spinach. Inbarley leaves, the levels of betaine aldehyde dehydrogenaseprotein were found to be enhanced by the addition of 200 mMNaCl to the growth medium. These changes in the level of theenzyme protein corresponded to those in the activity of theenzyme, as described in our previous study (Arakawa et al. 1990).The extent of this enhancement was reduced when barley plantswere relieved from salt stress. An increase in the level ofthe protein was also induced by water stress, such as the withholdingof water or the addition of polyethylene glycol 6000. Betainealdehyde dehydrogenase protein was detected in etiolated leavesand roots, as well as in green leaves. In etiolated leaves,the level of betaine aldehyde dehydrogenase protein was notaffected by salt stress. ¹ This work was supported by a grant from the Bio-Media Projectof the Japanese Ministry of Agriculture, Forestry and Fisheries(BMP92-III-l-1).     

Effects of rosuvastatin on electronegative LDL as characterized by capillary isotachophoresis: the ROSARY Study

Electronegative LDL, a charge-modified LDL (cm-LDL) subfraction that is more negatively charged than normal LDL, has been shown to be inflammatory. We previously showed that pravastatin and simvastatin reduced the electronegative LDL subfraction, fast-migrating LDL (fLDL), as analyzed by capillary isotachophoresis (cITP). The present study examined the effects of rosuvastatin on the more electronegative LDL subfraction, very-fast-migrating LDL (vfLDL), and small, dense charge-modified LDL (sd-cm-LDL) subfractions. Patients with hypercholesterolemia or those who were being treated with statins (n = 81) were treated with or switched to 2.5 mg/d rosuvastatin for 3 months. Rosuvastatin treatment effectively reduced cITP cm-LDL subfractions of LDL (vfLDL and fLDL) or sdLDL (sd-vfLDL and sd-fLDL), which were closely related to each other but were different from the normal subfraction of LDL [slow-migrating LDL (sLDL)] or sdLDL (sd-sLDL) in their relation to the levels of remnant-like particle cholesterol (RLP-C), apolipoprotein (apo) C-II, and apoE. The percent changes in cm-LDL or sd-cm-LDL caused by rosuvastatin were correlated with those in the particle concentrations of LDL or sdLDL measured as LDL-apoB or sdLDL-apoB and the levels of HDL-C, RLP-C, apoC-II, and apoE. In conclusion, rosuvastatin effectively reduced both the vfLDL subfraction and sd-cm-LDL subfractions as analyzed by cITP.     

New entry to the enantioselective formation of substituted cyclohexenes bearing an all-carbon quaternary stereogenic center

Enantioselective formation of cyclohexene derivatives bearing an all-carbon quaternary stereogenic center is described. The racemic cyclohexenes are readily transformed to chiral substituted cyclohexenes in good yield with excellent enantioselectivity and diastereoselectivity by a palladium-mediated deracemization. The resulting products are promising synthetic intermediates of biologically active natural products. This protocol provides us with a new entry to the concise and scalable synthesis of multifunctionalized compounds.     

Impact of brood parasitism and predation on nest survival of the fan-tailed gerygone in New Caledonia

Predation and brood parasitism are common reasons for nesting failure in passerine species and the additive impact by invasive species is a major conservation concern, particularly on tropical islands. Recognising the relative contribution of the different components of nesting failure rates is important to understand co-evolutionary interactions within brood parasite–host systems. In the remote archipelago of New Caledonia, the fan-tailed gerygone Gerygone flavolateralis is the exclusive host of the brood-parasitic shining bronze-cuckoo Chalcites lucidus. Additionally, invasive rodents also possibly have an impact on breeding success. To estimate the impact of potential nest predators, we 1) video monitored nests to identify predators, 2) estimated the probability of predation based on nest visibility and predator abundance and 3) tested the possibility that the location of experimental nests and lack of odour cues decrease the predation by rodents. In addition, we estimated nest survival rates using data collected in different habitats over the course of eight breeding seasons. Nesting success of fan-tailed gerygones was relatively low and predation was the main cause of nesting failure. We recorded mainly predation by native birds, including the shining bronze-cuckoo, whereas predation by rats was rare. In open habitats predation by cuckoos was much lower than predation by other avian predators. Neither predator activity around nests nor nest visibility influenced the probability of predation. Experimental nests in more accessible locations and containing an odorous bait were more exposed to rodent predation. Apparently, the fan-tailed gerygone has either never been specifically vulnerable to predation by rats or has developed anti-predator adaptations.     

Osmotic Stress Responses and Plant Growth Controlled by Potassium Transporters in Arabidopsis

Osmotic adjustment plays a fundamental role in water stress responses and growth in plants; however, the molecular mechanisms governing this process are not fully understood. Here, we demonstrated that the KUP potassium transporter family plays important roles in this process, under the control of abscisic acid (ABA) and auxin. We generated Arabidopsis thaliana multiple mutants for K⁺ uptake transporter 6 (KUP6), KUP8, KUP2/SHORT HYPOCOTYL3, and an ABA-responsive potassium efflux channel, guard cell outward rectifying K⁺ channel (GORK). The triple mutants, kup268 and kup68 gork, exhibited enhanced cell expansion, suggesting that these KUPs negatively regulate turgor-dependent growth. Potassium uptake experiments using ⁸⁶radioactive rubidium ion (⁸⁶Rb⁺) in the mutants indicated that these KUPs might be involved in potassium efflux in Arabidopsis roots. The mutants showed increased auxin responses and decreased sensitivity to an auxin inhibitor (1-N-naphthylphthalamic acid) and ABA in lateral root growth. During water deficit stress, kup68 gork impaired ABA-mediated stomatal closing, and kup268 and kup68 gork decreased survival of drought stress. The protein kinase SNF1-related protein kinases 2E (SRK2E), a key component of ABA signaling, interacted with and phosphorylated KUP6, suggesting that KUP functions are regulated directly via an ABA signaling complex. We propose that the KUP6 subfamily transporters act as key factors in osmotic adjustment by balancing potassium homeostasis in cell growth and drought stress responses.