Recognition and Response to Native and Novel Predators in the Largespring mosquitofish,Gambusia geiseri

The introduction of predator species into new habitats is an increasingly common consequence of human activities, and the persistence of native prey species depends upon their response to these novel predators. In this study, we examined whether the Largespring mosquitofish, Gambusia geiseri exhibited antipredator behavior and/or an elevation of circulating stress hormones (cortisol) to visual and chemical cues from a native predator, a novel predator, or a non‐predatory control fish. Prey showed the most pronounced antipredator response to the native predator treatment, by moving away from the stimulus, while the prey showed no significant changes in their vertical or horizontal position in response to the novel or non‐predator treatments. We also found no significant difference in water‐borne cortisol release rates following any of the treatments. Our results suggest the prey did not recognize and exhibit antipredator behavior to the novel predator, and we infer that this predator species could be detrimental if it expands into the range of this prey species. Further, our study demonstrates prey may not respond to an invasive predator that is phylogenetically, behaviorally, and morphologically dissimilar from the prey species' native predators.     

Mechanism of adhesion maintenance by methionine sulphoxide reductase in Streptococcus gordonii

Methionine sulphoxide reductase maintains adhesin function during oxidative stress. Using Streptococcus gordonii as a model, we now show the mechanistic basis of adhesin maintenance provided by MsrA. In biofilms, S. gordonii selectively expresses the msrA gene. When the wild-type strain was grown with exogenous hydrogen peroxide (H(2)O(2)), msrA-specific mRNA expression significantly increased, while acid production was unaffected. In the presence of H(2)O(2), a msrA-deletion mutant (ΔMsrA) showed a 6 h delay in lag phase growth, a 30% lower yield of H(2)O(2), significantly greater inhibition by H(2)O(2) on agar plates (reversed by complementation), 30% less adhesion to saliva-coated hydroxyapatite, 87% less biofilm formation and an altered electrophoretic pattern of SspAB protein adhesins. Using mass spectrometry, methionine residues in the Met-rich central region of SspB were shown to be oxidized by H(2)O(2) and reduced by MsrA. In intact wild-type cells, MsrA colocalized with a cell wall-staining dye, and MsrA was detected in both cell wall and cytosolic fractions. To maintain normal adhesion and biofilm function of S. gordonii in response to exogenous oxidants therefore msrA is upregulated, methionine oxidation of adhesins and perhaps other proteins is reversed, and adhesion and biofilm formation is maintained.     

The French lavender and lavandin industry

Oil of lavender, once produced to the extent of 150,000 kilograms annually in France from true lavender, has decreased to about 50,000 kilograms annually, having given way to a 300,000 kilogram production of lavandin from hybrids of true lavender and spike lavender.     

Smart peptide libraries are accessible via enzymatic modifications

The minireview summarizes the recent preparation of thefollowing unusually modified combinatorial peptide collectionsuseful for diagnostics and screening in drug finding. Tissuetransglutaminase catalyzes cross couplings with transamidationbetween Gln and Lys peptide chains resulting in libraries withisopeptide bonds. The enzyme is involved in the triggering ofautoantigenic B- and T-cell epitopes of coeliac disease. Themicrobial enzyme EpiD involved in lantibiotic biosynthesiscatalyzes oxidative decarboxylation of C-terminal cysteineresidues in peptide libraries transforming peptidyl-cysteinesto peptide (2-mercaptovinyl)amides. Novel backbone modifiedpeptide libraries are prepared using oxazole and thiazolebuilding blocks carrying amino acid side chains. These aminoacids have been found in many biologically active naturalproducts from marine and microbial organisms such as microcinB17. Dityrosine and isodityrosine linked peptide dimerlibraries are accessible by oxidative phenol coupling usinghorseradish peroxidase. Such structural elements are found forexample in the polycyclic glycopeptide antibiotics of thevancomycin type. Microstructured layers of linear and cyclicpeptide libraries are generated on transducer surfaces forcellular assays, sensor developments and even chiralrecognition. Examples include a light-directed andmicrostructured electrochemical polymerization of phenollabelled peptides.     

DNA repair and global sumoylation are regulated by distinct Ubc9 noncovalent complexes

Global sumoylation, SUMO chain formation, and genome stabilization are all outputs generated by a limited repertoire of enzymes. Mechanisms driving selectivity for each of these processes are largely uncharacterized. Here, through crystallographic analyses we show that the SUMO E2 Ubc9 forms a noncovalent complex with a SUMO-like domain of Rad60 (SLD2). Ubc9:SLD2 and Ubc9:SUMO noncovalent complexes are structurally analogous, suggesting that differential recruitment of Ubc9 by SUMO or Rad60 provides a novel means for such selectivity. Indeed, deconvoluting Ubc9 function by disrupting either the Ubc9:SLD2 or Ubc9:SUMO noncovalent complex reveals distinct roles in facilitating sumoylation. Ubc9:SLD2 acts in the Nse2 SUMO E3 ligase-dependent pathway for DNA repair, whereas Ubc9:SUMO instead promotes global sumoylation and chain formation, via the Pli1 E3 SUMO ligase. Moreover, this Pli1-dependent SUMO chain formation causes the genome instability phenotypes of SUMO-targeted ubiquitin ligase (STUbL) mutants. Overall, we determine that, unexpectedly, Ubc9 noncovalent partner choice dictates the role of sumoylation in distinct cellular pathways.     

Infusion of glucose and lipids at physiological rates causes acute endoplasmic reticulum stress in rat liver

Endoplasmic reticulum (ER) stress has recently been implicated as a cause for obesity-related insulin resistance; however, what causes ER stress in obesity has remained uncertain. Here, we have tested the hypothesis that macronutrients can cause acute (ER) stress in rat liver. Examined were the effects of intravenously infused glucose and/or lipids on proximal ER stress sensor activation (PERK, eIF2-α, ATF4, Xbox protein 1 (XBP1s)), unfolded protein response (UPR) proteins (GRP78, calnexin, calreticulin, protein disulphide isomerase (PDI), stress kinases (JNK, p38 MAPK) and insulin signaling (insulin/receptor substrate (IRS) 1/2 associated phosphoinositol-3-kinase (PI3K)) in rat liver. Glucose and/or lipid infusions, ranging from 23.8 to 69.5 kJ/4 h (equivalent to between ~17% and ~50% of normal daily energy intake), activated the proximal ER stress sensor PERK and ATF6 increased the protein abundance of calnexin, calreticulin and PDI and increased two GRP78 isoforms. Glucose and glucose plus lipid infusions induced comparable degrees of ER stress, but only infusions containing lipid activated stress kinases (JNK and p38 MAPK) and inhibited insulin signaling (PI3K). In summary, physiologic amounts of both glucose and lipids acutely increased ER stress in livers 12-h fasted rats and dependent on the presence of fat, caused insulin resistance. We conclude that this type of acute ER stress is likely to occur during normal daily nutrient intake.     

The effects of infant births on the sociosexual behavior and hormonal patterns of a cooperatively breeding primate (Cebuella pygmaea)

This study examined changes in the behavioral and hormonal patterns of cooperatively breeding pairs in a primate species with the passing of time and with specific reproductive events. We (1) compared patterns of sexual, agonistic, and affiliative behavior of newly paired pygmy marmosets with the same behavioral patterns immediately after the birth of their first set of infants; (2) determined if postpartum behavioral differences existed between pairs whose infants lived and those whose infants died; and (3) examined whether behavioral patterns changed over the course of ovarian cycles in parous pygmy marmosets as had been documented in nulliparous pairs. The behavior of pairs was recorded during daily half-hour focal samples for 60 days after pairing, and 30 or 60 days after the birth of infants for pairs whose litters died or lived, respectively. Daily urine samples from females during the study were analyzed for luteinizing hormone and pregnanediol glucuronide concentrations to determine dates of ovulation. The results indicated that males consistently altered their sexual behavior and olfactory monitoring of mates during periovulatory periods in the females' cycles both postpairing and postpartum, while similar rates of social and sexual behavior were maintained between the conditions. Sexual behavior occurred throughout the females' ovarian cycles. Peaks in sexual behavior during the periovulatory period in nulliparous pairs disappeared after the birth of infants. Pairs whose infants died showed higher rates of sexual behavior than pairs with surviving infants. Social and sexual behavior may function to maintain the relationship both during and outside of ovulation, especially with the loss of infants. © 1996 Wiley-Liss, Inc.     

The relationships of cholesterol metabolism and plasma plant sterols with the severity of coronary artery disease

Changes in the balance of cholesterol absorption and synthesis and moderately elevated plasma plant sterols have been suggested to be atherogenic. Measuring cholestanol, lathosterol, campesterol, and sitosterol, we investigated the relationships of cholesterol metabolism and plasma plant sterols with the severity of coronary artery disease (CAD) in 2,440 participants of the Ludwigshafen Risk and Cardiovascular health (LURIC) study. The coronary status was determined by angiography, and the severity of CAD was assessed by the Friesinger Score (FS). An increase in the ratio of cholestanol to cholesterol was associated with high FS (P = 0.006). In contrast, a high ratio of lathosterol to cholesterol went in parallel with low FS (P < 0.001). Whereas the campesterol to cholesterol ratio significantly correlated with the FS (P = 0.026), the relationship of the sitosterol to cholesterol ratio with the FS did not reach statistical significance in the whole group. Increased campesterol, sitosterol, and cholestanol to lathosterol ratios were associated high FS (P < 0.001). To conclude, there is a modest association of high cholesterol absorption and low cholesterol synthesis with an increased severity of CAD. An atherogenic role of plasma plant sterols themselves, however, seems unlikely in subjects without sitosterolaemia.