A combination of proteasome inhibitors and antibiotics prevents lethality in a septic shock model

Our recent studies with lactacystin, a prototype proteasome inhibitor, have suggested that the proteasome is a key regulator of LPS-induced signaling pathways contributing to the inflammatory process. Moreover, lactacystin protects animals from LPS-induced shock. Therefore, we sought to identify other less toxic compounds that would block the chymotrypsin-like activity of the proteasome or LPS-induced nitric oxide (NO). After screening over 100 natural compounds (based on chemistry and inhibition of LPS-induced biological activities), we now report for the first time that quercetin, like lactacystin (the prototype proteasome inhibitor), and mevinolin are also inhibitors of the chymotrypsin-like activity of the cellular proteasome within living cells. In addition, this study also suggests that mevinolin and quercetin both have relatively potent anti-inflammatory effects on LPS-treated macrophages in vitro. Interestingly, both of these compounds behave like lactacystin in that they block LPS-induced NO to a greater extent than TNF-alpha. The results of our experiments clearly suggest that mevinolin, in combination with the antibiotic imipenem, can provide protection against polymicrobial septic lethality induced by cecal-ligation and puncture in mice. Collectively, these studies strongly support the conclusion that therapeutic targeting of cellular proteasomes, in conjunction with standard antimicrobial therapy, may be of considerable survival benefit in the treatment of septic shock.     

Expression of NR2B in cerebellar granule cells specifically facilitates effect of motor training on motor learning

It is believed that gene/environment interaction (GEI) plays a pivotal role in the development of motor skills, which are acquired via practicing or motor training. However, the underlying molecular/neuronal mechanisms are still unclear. Here, we reported that the expression of NR2B, a subunit of NMDA receptors, in cerebellar granule cells specifically enhanced the effect of voluntary motor training on motor learning in the mouse. Moreover, this effect was characterized as motor learning-specific and developmental stage-dependent, because neither emotional/spatial memory was affected nor was the enhanced motor learning observed when the motor training was conducted starting at the age of 3 months old in these transgenic mice. These results indicate that changes in the expression of gene(s) that are involved in regulating synaptic plasticity in cerebellar granule cells may constitute a molecular basis for the cerebellum to be involved in the GEI by facilitating motor skill learning.     

Adding protein to a carbohydrate supplement provided after endurance exercise enhances 4E-BP1 and RPS6 signaling in skeletal muscle.

To examine the role of both endurance exercise and nutrient supplementation on the activation of mRNA translation signaling pathways postexercise, rats were subjected to a 3-h swimming protocol. Immediately following exercise, the rats were provided with a solution containing either 23.7% wt/vol carbohydrates (CHO), 7.9% wt/vol protein (Pro), 31.6% wt/vol (23.7% wt/vol CHO + 7.9% wt/vol Pro) carbohydrates and Pro (CP), or a placebo (EX). The rats were then killed at 0, 30, and 90 min postexercise, and phosphorylation states of mammalian target of rapamycin (mTOR), ribosomal S6 kinase (p70(S6K)), ribosomal protein S6 (rpS6), and 4E-binding protein 1 (4E-BP1), were analyzed by immunoblot analysis in the red and white quadriceps muscle. Results demonstrated that rat groups provided with any of the three nutritional supplements (CHO, Pro, CP) transiently increased the phosphorylation states of mTOR, 4E-BP1, rpS6, and p70(S6K) compared with EX rats. Although CHO, Pro, and CP supplements phosphorylated mTOR and p70(S6K) after exercise, only CP elevated the phosphorylation of rpS6 above all other supplements 30 min postexercise and 4E-BP1 30 and 90 min postexercise. Furthermore, the phosphorylation states of 4E-BP1 (r(2) = 0.7942) and rpS6 (r(2) = 0.760) were highly correlated to insulin concentrations in each group. These results suggest that CP supplementation may be most effective in activating the mTOR-dependent signaling pathway in the postprandial state postexercise, and that there is a strong relationship between the insulin concentration and the activation of enzymes critical for mRNA translation.     

C-TAK1 regulates Ras signaling by phosphorylating the MAPK scaffold, KSR1.

Kinase suppressor of Ras (KSR) is a conserved component of the Ras pathway that interacts directly with MEK and MAPK. Here we show that KSR1 translocates from the cytoplasm to the cell surface in response to growth factor treatment and that this process is regulated by Cdc25C-associated kinase 1 (C-TAK1). C-TAK1 constitutively associates with mammalian KSR1 and phosphorylates serine 392 to confer 14-3-3 binding and cytoplasmic sequestration of KSR1 in unstimulated cells. In response to signal activation, the phosphorylation state of S392 is reduced, allowing the KSR1 complex to colocalize with activated Ras and Raf-1 at the plasma membrane, thereby facilitating the phosphorylation reactions required for the activation of MEK and MAPK.     

Characterizing spring emergence of adult Halyomorpha halys using experimental overwintering shelters and commercial pheromone traps

To improve our understanding of adult Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) overwintering biology and to better inform models of its population dynamics, its temporal pattern of spring emergence was investigated using experimental overwintering shelters in screened cages within protective structures. In 2012, plastic shelters containing 100 adults were deployed in unheated, unlighted buildings, and adjacent woodlots in Virginia, USA. In 2013 and 2014, wooden shelters containing 300 paint‐marked adults were deployed in pairs in six woodlots across Virginia, West Virginia, and Maryland, USA; one in a closed cage and one in a cage with the top removed, enabling emerged adults to be counted or to disperse, respectively. In 2013 and 2014, pheromone‐baited and non‐baited pyramid traps encircled the shelters at each site. Regular counts of adults that emerged into the closed cage and of marked and ‘wild’ (unmarked) adults captured in traps were conducted from February or March through early July. In 2012, emergence patterns from shelters in buildings and woodlots were very similar and matched those recorded from woodlots in 2013 and 2014. In all years, a small peak of emergence occurred in about mid‐April, a larger and more prolonged peak was observed between mid‐May and early June, and emergence ended by early July. Of the 449 H. halys adults captured in traps between 2013 and 2014, only three were marked individuals from shelters in the open cage, suggesting that adults emerging from overwintering sites may require a dispersal flight before responding to pheromone‐baited traps. In 2013 and 2014, respectively, 98 and 93% of captures were in pheromone‐baited traps, but there was no correlation between the weekly number of adults that emerged from shelters in the closed cages and captures in traps.     

Sexual selection constrains the body mass of male but not female mice

Sexual size dimorphism results when female and male body size is influenced differently by natural and sexual selection. Typically, in polygynous species larger male body size is thought to be favored in competition for mates and constraints on maximal body size are due to countervailing natural selection on either sex; however, it has been postulated that sexual selection itself may result in stabilizing selection at an optimal mass. Here we test this hypothesis by retrospectively assessing the influence of body mass, one metric of body size, on the fitness of 113 wild‐derived house mice (Mus musculus) residing within ten replicate semi‐natural enclosures from previous studies conducted by our laboratory. Enclosures possess similar levels of sexual selection, but relaxed natural selection, relative to natural systems. Heavier females produced more offspring, while males of intermediate mass had the highest fitness. Female results suggest that some aspect of natural selection, absent from enclosures, acts to decrease their body mass, while the upper and lower boundaries of male mass are constrained by sexual selection.     

A Miscanthus plantation can be carbon neutral without increasing soil carbon stocks

National governments and international organizations perceive bioenergy, from crops such as Miscanthus, to have an important role in mitigating greenhouse gas (GHG) emissions and combating climate change. In this research, we address three objectives aimed at reducing uncertainty regarding the climate change mitigation potential of commercial Miscanthus plantations in the United Kingdom: (i) to examine soil temperature and moisture as potential drivers of soil GHG emissions through four years of parallel measurements, (ii) to quantify carbon (C) dynamics associated with soil sequestration using regular measurements of topsoil (0–30 cm) C and the surface litter layer and (iii) to calculate a life cycle GHG budget using site‐specific measurements, enabling the GHG intensity of Miscanthus used for electricity generation to be compared against coal and natural gas. Our results show that methane (CH₄) and nitrous oxide (N₂O) emissions contributed little to the overall GHG budget of Miscanthus, while soil respiration offset 30% of the crop's net aboveground C uptake. Temperature sensitivity of soil respiration was highest during crop growth and lowest during winter months. We observed no significant change in topsoil C or nitrogen stocks following 7 years of Miscanthus cultivation. The depth of litter did, however, increase significantly, stabilizing at approximately 7 tonnes dry biomass per hectare after 6 years. The cradle‐to‐farm gate GHG budget of this crop indicated a net removal of 24.5 t CO₂‐eq ha^?1 yr^?1 from the atmosphere despite no detectable C sequestration in soils. When scaled up to consider the full life cycle, Miscanthus fared very well in comparison with coal and natural gas, suggesting considerable CO₂ offsetting per kWh generated. Although the comparison does not account for the land area requirements of the energy generated, Miscanthus used for electricity generation can make a significant contribution to climate change mitigation even when combusted in conventional steam turbine power plants.