The use of ethidium bromide to assess a novel injury/recovery phenomenon in Listeria monocytogenes in inhibitory NaCl conditions

An injury and recovery phenomenon was observed in Listeria monocytogenes inoculated into a medium containing 2·2 mmol l⁻¹ NaCl, a concentration that was inhibitory to growth. The apparent loss then recovery of viability, as determined by plate counts, was compared with the uptake of ethidium bromide by the cells and found to be inversely related. Injury was caused not only by the initial osmotic up-shock but also by the subsequent down-shock involved in the spread plate protocol.     

Treatment of Early Breast Cancer: A Report after Ten Years of a Clinical Trial

A controlled clinical trial has been carried out to compare radical mastectomy with wide excision (extended tylectomy) in the treatment of early breast cancer. Only patients aged 50 and over were included and 370 entered the trial during a period of 10 years. Postoperative radiotherapy was given in each case. In patients with clinically involved axillary nodes there was a significantly higher incidence of local and distant recurrence in those having a wide excision, and the survival of these patients was significantly less than those who had a radical mastectomy. In patients with clinically uninvolved nodes, although there was a significantly higher incidence of local recurrence in those having a wide excision, there was no increased incidence of distant recurrence and the survival rate was similar to those having a radical mastectomy.     

Insulin release from a cloned hamster B-cell line (HIT-T15). The effects of glucose, amino acids, sulphonylureas and colchicine

Insulin release from statically incubated HIT-T15 cells was maximally stimulated by glucose, L-arginine and L-leucine. L-arginine stimulated insulin release in the absence of glucose. Glucose induced insulin release was potentiated by the addition of L-leucine, L-arginine and the two in combination. Both glibenclamide and chlorpropamide stimulated insulin release from HIT-T15 cells. Glibenclamide was the more potent and equivalent in insulinotrophic action to 7.5 mmol/l glucose. Only chlorpropamide significantly potentiated glucose induced insulin release. Perifused HIT-T15 cells produced a reproducible biphasic insulin response to glucose challenge which was characterised by a pronounced and sustained first phase and a reduced second phase. The stimulation of phase I by glibenclamide alone and the inhibition of phase II of glucose induced insulin release by colchicine suggested the presence of a readily available pool of insulin granules which was not rapidly restored by insulin biosynthesis and granule margination.     

Deuterium isotope effects in norcamphor metabolism by cytochrome P-450cam: kinetic evidence for the two-electron reduction of a high-valent iron-oxo intermediate

The kinetics of NADH consumption, oxygen uptake, and hydrogen peroxide production have been studied for norcamphor metabolism by cytochrome P-450cam. The kinetic deuterium isotope effects on these processes, with specifically deuteriated norcamphor, are 0.77, 1.22, and 1.16, respectively. Steady-state UV-visible spectroscopy indicates that transfer of the second electron to the dioxy ferrous P-450 is the rate-limiting step, as it is when camphor is the substrate. The inverse deuterium isotope effect for NADH consumption is consistent with an isotope-dependent branching between monooxygenase and oxidase activity, where these reactivities differ in their NADH:oxygen stoichiometries. However, no isotope-dependent redistribution of steady-state intermediates was detected by isotopic difference UV-visible spectroscopy in the presence of norcamphor. The kinetic isotope effects and steady-state spectral results suggest that the high-valent iron-oxo hydroxylating intermediate [FeO]3+ is reduced by NADH and the physiological electron-transfer proteins to afford water.     

Insecticidal effectiveness ofMammea Americana (Guttiferae) extracts on larvae ofDlabrotica Virgifera Virgifera (Coleoptera:Chrysomelidae) andTrichoplusia Ni (Lepidoptera:Noctuidae)

Seed and leaf extracts ofMammea americana (mamey apple) have a historical use as a biopesticide with the active components previously characterized. We reexamined the utility of this natural bioinsecticide in light of existing sources of material as a by-product of the fruit processing industry. Our results addDiabrotica virgifera virgifera andTrichoplusia ni to the list of insects which are susceptible to the insecticidal ingredients ofM. americana and confirms earlier reports of activity againstBlatella germanica, Periplaneta americana, andPlutella xylostella. We report LD5Os for crude hexane extracts ofM. americana leaves and seeds againstT. ni. These materials represent renewable sources of bioinsecticides for agriculture, and should regenerate interest in coumarin-type compounds for novel pesticidal action.     

The influence of feeding,enrichment, and seasonal context on the behavior of Pacific Walruses (Odobenus rosmarus divergens)

Though some research exists concerning general behavior and activity patterns of Walruses in zoos or aquariums, less is known about how these patterns change in response to various environmental and temporal contexts. This study presents two studies assessing behavioral changes in relation to feeding period, object enrichment (OE), and season in a social group of four Pacific Walruses at the New York Aquarium. Study 1 examined behavior in relation to feeding context (nonfeed, prefeed, postfeed); data were collected over a three‐week period, resulting in 47 observation sessions for each feeding context. Study 2 examined behavior in relation to OE and season; data were collected in two phases resulting in 12 enrichment and 9 no‐enrichment (NE) observation sessions (Phase 1), and 21 enrichment and 18 NE observation sessions (Phase 2). Study 1 showed that after feeding, oral behavior increased while social behavior and total swim frequency decreased. In Study 2, both swim frequency and social behavior were found to interact with OE and phase, while oral behavior remained constant across all conditions. As in the wild, both studies found all animals to be swimming the majority of the time. Though every animal spent much of its swim time engaged in an Individual Swimming Pattern (ISP), both studies showed that the proportion of ISP (in relation to total time swimming) remained stable across all contexts, suggesting a potential functional role of the ISPs. These results are discussed in light of the ongoing debate over the role of stereotypies in welfare assessment. Zoo Biol 29:397–404, 2010. © 2009 Wiley‐Liss, Inc.     

Recurrent Emergence of Catalytically Inactive Ornithine Decarboxylase Homologous Forms That Likely Have Regulatory Function

Ornithine decarboxylase (ODC) catalyzes the first and rate limiting step in the biosynthesis of polyamines in most eukaryotes. Because polyamines have pleiotropic and often dramatic effects on cellular processes at both high and low concentrations, ODC expression is tightly controlled. ODC is regulated by a family of polyamine-induced proteins, antizymes, which bind to, and inactivate it. In mammals, and apparently most vertebrates, antizymes are in turn antagonized by proteins called antizyme inhibitors. Antizyme inhibitors are homologs of ODC that have lost their decarboxylation activity but have retained their ability to bind antizyme, in most cases even more tightly than ODC. We present a phylogenetic analysis of over 200 eukaryotic homologs of ODC and evaluate their potential to be either true ODCs or catalytically inactive proteins that might be analogs of the previously identified antizyme inhibitors. This analysis yielded several orthologous groups of putative novel antizyme inhibitors each apparently arising independently. In the process we also identify previously unrecognized ODC paralogs in several evolutionary branches, including a previously unrecognized ODC paralog in mammals, and we evaluate their biochemical potential based on their pattern of amino acid conservation.