Inbreeding depression in the Zebra fish Brachydanio rerio (Hamilton Buchanan)

Inbreeding depression was observed in Half and Full sib matings (Inbreeding Coefficient 0.125 and 0.25) of Zebra Danios ( Brachydanio rerio ). Inbreeding at these levels reduced fertility, survival to 30 days, and length at 30 days. There was an increase in the incidence of crippled fry. No effect of inbreeding on either number of eggs per spawn or hatchability were found.     

Mate inspection patterns in the female beaugregory damselfish (<Emphasis Type="Italic">Stegastes leucostictus</Emphasis>)

We observed female beaugregory damselfish (Stegastes leucostictus) as they interacted with males to see whether their movements fit the predictions of different mate-search models. We established high-quality and low-quality groups with low variance in breeding site quality and a medium-quality, high-variance breeding site group and compared focal observations of female nonforaging forays in each group. Only 8% of 137 forays monitored resulted in spawning events. Eighty-nine percent of the forays were less than 240 s and were within 7 m of the focal female’s territory. Average foray times and straight-line foray distances did not differ for females traveling between males in each group. Females entered high-quality breeding sites at a higher rate than low-quality sites and round-trip distances were also greatest in high-quality groups, indicating that females were following a more convoluted path. We interpret these results to mean that (a) female beaugregories separate the tasks of mate assessment and mate choice by conducting information-gathering forays between mating events, (b) forays are energetically costly and therefore usually short in duration and overall distance traveled, (c) information collection takes approximately the same time for high-quality and low-quality mates, but (d) females will alter their foray patterns in high-quality areas to collect additional information. These data are also consistent with the hypothesis that females optimize their search by employing a tiered process of assessment during information-gathering forays, first using an adjustable threshold to accept or reject each male based on his courtship and subsequently a fixed threshold to assess the quality of each breeding site.     

Effects of fetal urinary corticosteroids, catecholamines and kallikrein on PGE2 synthesis in monolayer cultures of human amnion and chorion cells

We have studied the effects of several compounds isolated from fetal urine on the production of PGE2 by amnion and chorion cells which were maintained in primary monolayer culture. We conclude that desoxycorticosterone and vanillylmandelic acid stimulate PGE2 synthesis by amnion, but adrenaline and kallikrein increase the biosynthesis of PGE2 by chorion. These data suggest that human fetal urine could play a major role in events of parturition.     

Biomass accumulation over the first 150 years in coastal Oregon Picea‐Tsuga forest

Abstract. Production and mortality are the component processes that together determine the biomass dynamics of forests. Due to the significant role of forests in the global carbon cycle, it is important to assess how these two processes affect the maximum biomass attained by forests, as well as the dynamics leading up to and following peak biomass. We address these questions for two sets of plots in Picea sitchensis‐Tsuga heterophylla forest on the northern Oregon coast that originated from a catastrophic wildfire in the 1840s, using new data on dynamics of live trees and stocks of coarse woody debris (CWD). The set of plots closest to the ocean and occupying steeper, more dissected terrain with areas of thin soils has lower biomass, lower net primary production (NPP) of bole wood and higher tree mortality as a fraction of standing biomass. The two sets of plots have similar CWD levels, most of which has accumulated in the last 25 yr. The present disparity in biomass between the two sets of plots appears to be the result of lower NPP on the low‐biomass plots for the entire 140+ yr history of the forest. Over the 58 yr that the high‐biomass plots have been measured (from stand age 85 to 143 yr), NPP of bole wood has declined by 41%. Only ca. 6% of this decline can be accounted for by an increase in maintenance respiration of woody tissues. For both sets of plots relative constancy of biomass in the long term appears likely, due to a short time lag in tree regeneration, asynchronous tree mortality and little overall decline in NPP of bole wood in recent decades. However, since tree mortality as a fraction of standing biomass is higher on the low‐biomass plots, and NPP of bole wood is slightly lower, the difference in biomass between the two sets of plots should increase if current rates of production and mortality persist.     

Forced expression of the cell cycle inhibitor p57<Superscript>Kip2</Superscript> in cardiomyocytes attenuates ischemia-reperfusion injury in the mouse heart

Background  

Myocardial hypoxic-ischemic injury is the cause of significant morbidity and mortality worldwide. The cardiomyocyte response to hypoxic-ischemic injury is known to include changes in cell cycle regulators. The cyclin-dependent kinase inhibitor p57 ^Kip2 is involved in cell cycle control, differentiation, stress signaling and apoptosis. In contrast to other cyclin-dependent kinase inhibitors, p57^Kip2 expression diminishes during postnatal life and is reactivated in the adult heart under conditions of cardiac stress. Overexpression of p57 ^Kip2 has been previously shown to prevent apoptotic cell death in vitro by inhibiting stress-activated kinases. Therefore, we hypothesized that p57 ^Kip2 has a protective role in cardiomyocytes under hypoxic conditions. To investigate this hypothesis, we created a transgenic mouse (R26loxpTA-p57 ^k/+) that expresses p57^Kip2 specifically in cardiac tissue under the ventricular cardiomyocyte promoter Mlc2v.     

Institutional Management of Core Facilities during Challenging Financial Times

The economic downturn is likely to have lasting effects on institutions of higher education, prioritizing proactive institutional leadership and planning. Although by design, core research facilities are more efficient and effective than supporting individual pieces of research equipment, cores can have significant underlying financial requirements and challenges. This paper explores several possible institutional approaches to managing core facilities during challenging financial times.