Evidence for numerous analogs of yessotoxin in Protoceratium reticulatum

A solid-phase extract from Protoceratium reticulatum was partitioned between water and butanol and the two fractions purified on an alumina column. Fractionation was monitored by ELISA and LC–MS. Results indicate that while almost all yessotoxin (1) was extracted into butanol, large amounts of yessotoxin analogs remained in the aqueous extract along with lesser amounts in the butanolic extract. NMR analysis of selected fractions from reverse-phase chromatography of the extracts confirmed the presence of yessotoxin analogs, although structure determinations were not possible due to the complexity of the mixtures. Analysis of fractions with LC–MS³ and neutral-loss LC–MS/MS indicated the presence of more than 90 yessotoxin analogs, although structures for most of these have not yet been determined. These analogs provide a mechanism to rationalise the discrepancy between ELISA and LC–MS analyses of algae and shellfish.     

Identification of novel non-phosphorylated ligands, which bind selectively to the SH2 domain of Grb7.

Grb7 is an adapter-type signaling protein, which is recruited via its SH2 domain to a variety of receptor tyrosine kinases (RTKs), including ErbB2 and ErbB3. It is overexpressed in breast, esophageal, and gastric cancers, and may contribute to the invasive potential of cancer cells. Molecular interactions involving Grb7 therefore provide attractive targets for therapeutic intervention. We have utilized phage display random peptide libraries as a source of small peptide ligands to the SH2 domain of Grb7. Screening these libraries against purified Grb7 SH2 resulted in the identification of Grb7-binding peptide phage clones that contained a non-phosphorylated Tyr-X-Asn (YXN) motif. The tyrosine-phosphorylated form of this motif is characteristic of Grb7 SH2 domain binding sites identified in RTKs and other signaling proteins such as Shc. Peptides that are non-phosphorylated have greater potential in the development of therapeutics because of the instability of a phosphate group in vivo. Using a biased library approach with this conserved YXN motif, we identified seven different peptide phage clones, which bind specifically to the SH2 domain of Grb7. These peptides did not bind to the SH2 domain of Grb2 (which also selects for Asn at pY(+2)) or Grb14, a closely related family member. The cyclic structure of the peptides was required to bind to the Grb7 SH2 domain. Importantly, the synthetic Grb7-binding peptide G7-18 in cell lysates was able to specifically inhibit the association of Grb7 with the ErbB family of RTKs, in particular ErbB3, in a dose-dependent manner. These peptides will be useful in the development of targeted molecular therapeutics for cancers overexpressing Grb7 and in the development of Grb7-specific inhibitors to gain a complete understanding of the physiological role of Grb7.     

Chick provisioning and breeding success of Adélie penguins at Béchervaise Island over eight successive seasons

Data on foraging trip durations and meal sizes were collected by means of an automated monitoring system from breeding Adélie penguins (Pygoscelis adeliae) at Béchervaise Island over eight breeding seasons, commencing in 1991-92. Significant interannual differences in duration of foraging trips, meal sizes and diet composition were observed. These parameters were correlated with breeding success and fledging masses, and provide useful indicators of food availability during the breeding season. Chicks were particularly vulnerable to a decreased availability of food during the first 3 weeks after hatching.     

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 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.     

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.     

Post-translational Regulation of Mitogen-activated Protein Kinase Phosphatase (MKP)-1 and MKP-2 in Macrophages Following Lipopolysaccharide Stimulation: THE ROLE OF THE C TERMINI OF THE PHOSPHATASES IN DETERMINING THEIR STABILITY*

MAPK phosphatases (MKPs) are critical modulators of the innate immune response, and yet the mechanisms regulating their accumulation remain poorly understood. In the present studies, we investigated the role of post-translational modification in the accumulation of MKP-1 and MKP-2 in macrophages following LPS stimulation. We found that upon LPS stimulation, MKP-1 and MKP-2 accumulated with different kinetics: MKP-1 level peaked at ∼1 h, while MKP-2 levels continued to rise for at least 6 h. Accumulation of both MKP-1 and MKP-2 were attenuated by inhibition of the ERK cascade. Interestingly, p38 inhibition prior to LPS stimulation had little effect on MKP-1 and MKP-2 protein levels, but hindered their detection by an M-18 MKP-1 antibody. Studies of the epitope sequence recognized by the M-18 MKP-1 antibody revealed extensive phosphorylation of two serine residues in the C terminus of both MKP-1 and MKP-2 by the ERK pathway. Remarkably, the stability of both MKP-1 and MKP-2 was markedly decreased in macrophages in the presence of an ERK pathway inhibitor. Mutation of the two C-terminal serine residues in MKP-1 and MKP-2 to alanine decreased their half-lives, while mutating these residues to aspartate dramatically increased their half-lives. Deletion of the C terminus from MKP-1 and MKP-2 also considerably increased their stabilities. Surprisingly, enhanced stabilities of the MKP-1 and MKP-2 mutants were not associated with decreased ubiquitination. Degradation of both MKP-1 and MKP-2 was attenuated by proteasomal inhibitors. Our studies suggest that MKP-1 and MKP-2 stability is regulated by ERK-mediated phosphorylation through a degradation pathway independent of polyubiquitination.     

Sex Differences in Territorial Behavior Exhibited by the Spotted Hyena (Hyaenidae, Crocuta crocuta)

Spotted hyenas ( Crocuta crocuta ) are gregarious carnivores that defend group territories against encroachment by neighboring conspecifics. Here we monitored the behavior of members of one clan of free-ranging spotted hyenas during border patrols, 'wars' with neighboring clans, and other interactions with alien intruders, to document differences between the sexes in territorial behavior in this species. We also examined the possibility that the probability or rate of attack on alien hyenas encountered within the clan's territory would vary with the sex of the intruders. Initiation and leadership of most cooperative territorial behaviors were by adult female clan members, although border patrols were occasionally conducted by groups composed exclusively of resident males. The vast majority of alien intruders into the territory of the study clan were males. Resident females were more likely to attack intruding females than intruding males, but hourly rates of aggression directed by females towards aliens did not vary with intruder sex. Resident males were more likely than resident females to attack alien males, and resident males directed significantly higher hourly rates of aggression towards intruding males than females. Although female leadership in most cooperative territorial behaviors distinguishes spotted hyenas from many mammalian carnivores, other sex differences in the territorial behavior of spotted hyenas resemble those documented in other gregarious predators. Sex differences observed in hyena territoriality are consistent with the hypothesis that male and female clan members derive different selective benefits from advertisement and defense of group territories.