Rapid Kill—Novel Endodontic Sealer and Enterococcus faecalis

With growing concern over bacterial resistance, the identification of new antimicrobial means is paramount. In the oral cavity microorganisms are essential to the development of periradicular diseases and are the major causative factors associated with endodontic treatment failure. As quaternary ammonium compounds have the ability to kill a wide array of bacteria through electrostatic interactions with multiple anionic targets on the bacterial surface, it is likely that they can overcome bacterial resistance. Melding these ideas, we investigated the potency of a novel endodontic sealer in limiting Enterococcus faecalis growth. We used a polyethyleneimine scaffold to synthesize nano-sized particles, optimized for incorporation into an epoxy-based endodontic sealer. The novel endodontic sealer was tested for its antimicrobial efficacy and evaluated for biocompatibility and physical eligibility. Our results show that the novel sealer foundation affixes the nanoparticles, achieving surface bactericidal properties, but at the same time impeding nanoparticle penetration into eukaryotic cells and thereby mitigating a possible toxic effect. Moreover, adequate physical properties are maintained. The nanosized quaternary amine particles interact within minutes with bacteria, triggering cell death across wide pH values. Throughout this study we demonstrate a new antibacterial perspective for endodontic sealers; a novel antibacterial, effective and safe antimicrobial means.     

Evidence for an autumn downstream migration of Atlantic salmon Salmo salar (Linnaeus) and brown trout Salmo trutta (Linnaeus) parr to the Baltic Sea

In the eastern Baltic rivers, anadromous salmonid parr are known to smoltify and migrate to the sea from March until June, depending on latitude, climate and hydrological conditions. In this study, we present the first records of autumn descent of brown trout Salmo trutta and Atlantic salmon Salmo salar from the Baltic Sea Basin. Otolith microchemistry analyses revealed that these individuals hatched in freshwater and had migrated to the brackish water shortly prior to capture. The fish were collected in 2006, 2008, 2009 and 2013 from Eru Bay (surface salinity 4.5–6.5 ‰), Gulf of Finland. This relatively wide temporal range of observations indicates that the autumn descent of anadromous salmonids is not a random event. These results imply that autumn descent needs more consideration in the context of the effective stock management, assessment and restoration of Baltic salmonid populations and their habitats.     

Evidence of Atlantic salmon Salmo salar fry movement between fresh water and a brackish environment

This study reports descent of Atlantic salmon Salmo salar fry from their natal streams to brackish waters of the Baltic Sea and their use of this environment as an alternative rearing habitat before ascending back to freshwater streams. To the authors' knowledge, residency in a brackish environment has not previously been demonstrated in S. salar fry. Recruitment success and evolutionary significance of this alternative life‐history strategy are presently not known.     

Particle transport by benthic invertebrates: its role in egg bank dynamics

The ecological and evolutionary dynamics of zooplankton is in part a function of the numbers and ages of dispausing eggs hatching from aquatic sediments. Successful recruitment from this egg bank must depend upon the eggs being present at or near the sediment surface. Often, however, zooplankton diapausing eggs are found as deep as 15 to 30 cm in the mud. Bioturbation may provide a mechanism for the regular return of buried eggs to the sediment surface. A substantial portion of the population of the copepod, Diaptomus sanguineus, living in Bullhead Pond, a small lake in Rhode Island, USA, is present as diapausing eggs. To study the role of bioturbation in egg-bank dynamics, we introduced polystyrene beads, the same size and specific gravity as copepod eggs, at two depths in large-diameter sediment chambers in the laboratory. Treatments included chambers with natural and reduced densities of benthos. Consistent with other studies, our results show that the joint activities of tubificid oligochaetes and chironomid larvae are responsible for bidirectional (up and down) transport of beads in the top 2 cm of the sediment. We observed no bead movement below this depth. Thus, eggs in the top two centimeters of sediment in this lake are exposed with some regularity to conditions that stimulate hatching at the sediment-water interface. In Bullhead Pond, these eggs have a mean age of 12.2 years (based on ²¹⁰Pb-dating). Eggs buried more deeply will only be returned to the sediment surface by relatively rare, localized disturbances. This return of old eggs to the surface affects ecological and evolutionary dynamics in a complex way.     

Reproductive hormone secretions in pony mares subsequent to ovulation control during late winter

Beginning in December, pony mares were placed under a schedule of increasing light. Starting in February, onset of estrus was checked by daily teasing with a stallion. Mares were randomly assigned to one of three treatments (6 mares per group) administered in March. Treatments were: Group I — 75 mg progesterone injected intramuscularly every day for 10 days in combination with a 1.25 mg injection of PGF₂α on day 7 of progesterone treatment and a 2,000 IU injection of HCG on day 2 of estrus; Group II — a norgestomet ear implant inserted for 10 days in combination with 1.25 mg PGF₂α given 7 days after insertion and 2,000 IU HCG administered on day 2 of estrus; and Group III — same as II except that 2 mg of GnRH rather than HCG were administered on day 2 of estrus. Blood plasma for radioimmunoassay of progesterone, LH and estradiol was collected from the first day of treatment until 14 days after the end of estrus. Also in March, 6 mares were bled daily from the first day of estrus until subsequent estrus or day 21 (control estrus). Although estrus was detected in all mares, 14 of 18 mares ovulated subsequent to treatments and four of the six control estrus mares ovulated. Only among HCG treated mares was the ovulation rate higher (P < .05) than it was in the control estrus group. The interval from last progesterone injection or norgestomet implant removal to estrus did not differ between treatment groups. Concentrations of estradiol and LH were increased for several days around the time of ovulation and tended to be positively correlated with each other. In the mares that did not ovulate, concentrations of LH and estradiol appeared to be lower than in mares that ovulated. In summary, progestins in combination with PGF₂α and increasing light will synchronize estrus in mares during late winter and HCG will hasten ovulation in some mares.     

Leaf herbivory increases floral fragrance in male but not female Cucurbita pepo subsp. texana (Cucurbitaceae) flowers

Mutualisms are key interactions that affect population dynamics and structure communities, but the extent to which mutualists can attract potential partners may depend on community context. Many studies have shown that leaf herbivory reduces pollinator visitation and have focused on reduced floral visual display and rewards as potential mechanisms. However, olfactory display plays a critical role in mediating interactions between plants, herbivores, and pollinators. We simulated leaf damage in Cucurbita pepo subsp. texana and measured fragrance emission and other floral characters of both male and female flowers. Contrary to our expectations, damage increased fragrance production, but only in male flowers. Female flowers, which were bigger and produced more fragrance than males, were unaffected by leaf damage. The greatest increase in floral fragrance compounds was in the terpenoids, which we hypothesize could be byproducts of defensively induced cucurbitacins, or they may function defensively themselves. In summary, this study is the first to demonstrate changes in floral fragrance due to leaf damage. Such changes in floral fragrance following herbivory may be a critical and overlooked mechanism mediating interactions between plants, herbivores, and pollinators.     

Contraceptive efficacy of a novel intrauterine device (IUD) in white-tailed deer

Overabundant white-tailed deer (Odocoileus virginianus) pose risks to property, health, and safety of human beings. Public concerns about lethal management can impair efforts to address these issues, particularly in urban settings. Several techniques developed for reducing reproductive output of deer have limited utility because they require repeated dosing to achieve permanent effect and face uncertain regulatory approval for use beyond experimentation. From 10 August 2006 through 30 December 2007, we evaluated the contraceptive efficacy of copper-containing intrauterine devices (IUDs) implanted trans-cervically in white-tailed deer at the E.S. George Reserve in Pinckney, Michigan. Intrauterine devices were implanted before (n = 9) and shortly after (n = 10) the breeding season. Post-breeding season IUD treatment was in conjunction with a 5 cm³ dose of 5 mg/ml prostaglandin F_2α (PGF_2α), delivered subcutaneously. Intrauterine devices reduced pregnancy rates when administered prior to breeding (P < 0.001) and prevented pregnancy for up to 2 years (the duration of the study). Two of 8 does that received IUDs prior to the breeding season and survived to the end of the study became pregnant (due to loss of the implant) during the second year while all (n = 16) does without implants conceived. Cervical changes associated with early pregnancy made trans-cervical implantation after the breeding season challenging, and resulted in improperly placed IUDs in 2 treated does. The apparent expulsion of IUDs by pregnant does that received the combined treatment after breeding suggests IUD treatment should be limited to the pre-breeding season. Intrauterine devices show potential as a tool for small-scale deer population management via non-steroidal reproductive inhibition.