Stimulation of the α7 Nicotinic Acetylcholine Receptor Protects against Neuroinflammation after Tibia Fracture and Endotoxemia in Mice

Surgery and critical illness often associate with cognitive decline. Surgical trauma or infection can lead independently to learning and memory impairments via similar, but not identical, cellular signaling of the innate immune system that promotes neuroinflammation. In this study we explored the putative synergism between aseptic orthopedic surgery and infection, the latter reproduced by postoperative lipopolysaccharide (LPS) administration. We observed that surgery and LPS augmented systemic inflammation up to postoperative d 3 and this was associated with further neuroinflammation (CD11b and CD68 immunoreactivity) in the hippocampus in mice compared with those receiving surgery or LPS alone. Administration of a selective α7 subtype nicotinic acetylcholine receptor (α7 nAChR) agonist 2 h after LPS significantly improved neuroinflammation and hippocampal-dependent memory dysfunction. Modulation of nuclear factor-kappa B (NF-κB) activation in monocytes and regulation of the oxidative stress response through nicotinamide adenine dinucleotide phosphate (NADPH) signaling appear to be key targets in modulating this response. Overall, these results suggest that it may be conceivable to limit and possibly prevent postoperative complications, including cognitive decline and/or infections, through stimulation of the cholinergic antiinflammatory pathway.     

On Countable Mixtures of Bivariate Binomial Distributions

A unified treatment is given for mixtures of bivariate binomial distributions with respect to their index parameter(s). The use of probability generating functions is employed and a number of interesting properties including probabilities, factorial moments, factorial cumulants and conditional distributions are derived. Five classes of such mixtures are examined and several well known bivariate discrete distributions are used as illustrative examples. Biological applications are indicated including the fit of three bivariate distributions to an actual set of human family data.     

Trophic cascades in tropical rainforests: Effects of vertebrate predator exclusion on arthropods and plants in Papua New Guinea

Insect herbivores have the potential to consume large amounts of plant tissue in tropical forests, but insectivorous vertebrates effectively control their abundances, indirectly increasing plant fitness accordingly. Despite several studies already sought understanding of the top-down effects on arthropod community structure and herbivory, such studies of trophic cascades in old tropics are underrepresented, and little attention was paid to top-down forces in various habitats. Therefore, we examine how flying insectivorous vertebrates (birds and bats) impact arthropods and, consequently, affect herbivore damage of leaves in forest habitats in Papua New Guinea. In a 3-month long predator exclosure experiment conducted at four study sites across varying elevation and successional stage, we found that vertebrate predators reduced arthropod density by ∼52%. In addition, vertebrate predators decreased the mean body size of arthropods by 26% in leaf chewers and 47% in non-herbivorous arthropods but had only a small effect on mesopredators and sap suckers. Overall, the exclusion of vertebrate predators resulted in a ~ 41% increase in leaf damage. Our results, across different types of tropical forests in Papua New Guinea, demonstrate that flying vertebrate insectivores have a crucial impact on plant biomass, create a selective pressure on larger and non-predatory prey individuals and they prey partition with mesopredators.     

Variations in the volumes of parenchyma and stroma of the liver and in the cytology of hepatocytes are associated with gonadal stages in female Ohrid trout (Salmo letnica)

Quantitative microscopic studies of season- and breeding-related changes in the liver of farm-raised fish are very scarce, and those of wild fish populations are virtually nonexistent. Moreover, none of the available studies investigated breeding-related changes in hepatic stroma, although it is already known that changes might exist in the parenchyma. To the best of our knowledge, ours is the first study using wild adult Ohrid trout females to evaluate quantitative influences of the breeding cycle on the volumes of the two liver compartments—parenchyma and stroma. Quantitative microscopy (stereology) using light microscopy was supplemented with semi-quantitative and quantitative analyses of hepatocyte cytology to express in numbers the seasonal changes in the extent of vacuolated versus basophilic cytoplasm. The liver volume and that of each compartment changed from that at the time of pre-vitellogenesis to the end of the spawning season. The changes in total volumes of parenchyma and stroma—increasing from pre-vitellogenesis to late vitellogenesis—followed the changes in total liver volume. Despite all the changes in total volumes, no differences existed in the relative proportions between the two major compartments. After spawning, the stromal volume continued to increase while that of the parenchyma reduced despite no detectable statistically significant impacts on the liver volume. Changes in both the liver and parenchyma volumes were correlated with the gonadosomatic index and plasma oestradiol levels. With this study, we first establish that fish liver remodelling might also occur in the stroma. When comparing Ohrid trout with other fish species, we noted interspecies similarities and differences with regard to the hepatocyte cytology during the breeding cycle. In our study, the semi-quantitative and stereological studies revealed that, from pre-vitellogenesis to post-spawning, although cytoplasmic vacuolation of the hepatocytes decreased, the basophilia increased. Overall, these cytological changes were only partially in agreement with the data from other trout studies. We believe that this is because of intrinsic interspecies differences in association with natural conditions. Thus, establishing normal patterns is crucial, at least for flagship species, namely to support interpretation of histopathological changes in biomonitoring.     

Single Nucleotide Variants in KIF14 Gene May Have Prognostic Value in Breast Cancer

Molecular Diagnosis & Therapy - Human kinesin 14 (KIF14) is one of the 70 prognostic marker genes (so-called Amsterdam profile) previously identified by the microarray of breast carcinomas, and...     

Effect of forest fragmentation on bird species richness in Papua New Guinea

Tropical forests worldwide are being fragmented at a rapid rate, causing a tremendous loss of biodiversity. Determining the impacts of forest disturbance and fragmentation on tropical biotas is therefore a central goal of conservation biology. We focused on bird communities in the interior (>100 m from forest edge) of forest fragments (300, 600, and 1200 ha) in the lowlands of Papua New Guinea and compared them with those in continuous forest. We surveyed bird communities using point counts, mist‐netting, and random walks, and measured habitat and microclimate characteristics at each site. We also surveyed leaf‐dwelling arthropods, butterflies, and ants, and obtained diet samples from birds to examine food availability and food preferences. We recorded significantly fewer bird species per point in the 300‐ha forest fragment than in other study sites. Overall, we recorded 80, 84, and 88 species, respectively, in forest fragments, and 102 in continuous forest. Frugivores (especially large frugivores) and insectivores had lower species richness in forest fragments than continuous forest. Our results did not support the food scarcity hypothesis, that is, the decline of insectivorous birds in forest fragments is caused by an impoverished invertebrate prey base. We also found no significant differences among forest fragments and continuous forest in microclimates of forest interiors. Rather, we found that microhabitats preferred by sensitive birds (i.e., 30% of species with the strongest preferences for continuous forest) were less common in forest fragments (19%–31% of points) than in continuous forest (86% of points). Our results suggest that changes in microhabitats may make forest fragments unsuitable for sensitive species. However, limited dispersal capabilities could also make some species of birds less likely to disperse and occupy fragments. In addition, impoverished food resources, size of the forest fragment, or hunting pressure could contribute to the absence of large frugivorous birds in forest fragments. The forest fragments in our study, preserved as village‐based protected areas, were not large enough to sustain the bird communities found in continuous forest. However, because these fragments still contained numerous bird species, preservation of such areas can be an important component of management strategies to conserve rainforests and birds in Papua New Guinea.     

Single-molecule visualization of human RECQ5 interactions with single-stranded DNA recombination intermediates

RECQ5 is one of five RecQ helicases found in humans and is thought to participate in homologous DNA recombination by acting as a negative regulator of the recombinase protein RAD51. Here, we use kinetic and single molecule imaging methods to monitor RECQ5 behavior on various nucleoprotein complexes. Our data demonstrate that RECQ5 can act as an ATP-dependent single-stranded DNA (ssDNA) motor protein and can translocate on ssDNA that is bound by replication protein A (RPA). RECQ5 can also translocate on RAD51-coated ssDNA and readily dismantles RAD51–ssDNA filaments. RECQ5 interacts with RAD51 through protein–protein contacts, and disruption of this interface through a RECQ5–F666A mutation reduces translocation velocity by ∼50%. However, RECQ5 readily removes the ATP hydrolysis-deficient mutant RAD51–K133R from ssDNA, suggesting that filament disruption is not coupled to the RAD51 ATP hydrolysis cycle. RECQ5 also readily removes RAD51–I287T, a RAD51 mutant with enhanced ssDNA-binding activity, from ssDNA. Surprisingly, RECQ5 can bind to double-stranded DNA (dsDNA), but it is unable to translocate. Similarly, RECQ5 cannot dismantle RAD51-bound heteroduplex joint molecules. Our results suggest that the roles of RECQ5 in genome maintenance may be regulated in part at the level of substrate specificity.     

Aluminum ions inhibit phospholipase D in a microtubule-dependent manner.

Aluminum is a highly cytotoxic metal to plants, but the molecular base and the primary target of Al toxicity are still unknown. The most important physiological consequence of Al toxicity is a cessation of root growth and changes in root morphology suggesting a role of the root cytoskeleton as a target structure. The important role of phospholipid degrading enzyme phospholipase D in regulation of cytoskeleton remodelling in both animal and plant organisms is now evident. Both the phospholipid pathway and the cytoskeleton are influenced by Al(3+), but their relationship with Al stress remains to be explored. Therefore, we tested the possibility that Al stress could be sensed by plants through microtubules in close interaction with phospholipases. We have shown that Al(3+) reduced the formation of phosphatidic acid in vivo, inhibited activity of phosphatidylinositol-4,5-bisphosphate-dependent phospholipase D in vitro and that the phosphatidic acid production is modified by microtubule dynamics.     

Micropropagation and salt tolerance of in vitro grown Crithmum maritimum L.

Crithmum maritimum (Apiaceae), a perennial halophyte native in Greece, could be used as an alternative culture at problematic soils. It presents significant economical potentials as its essential oils are in high demand from the medicinal and cosmetic industry. The response of the species on in vitro conditions was studied. MS proved to be the most effective of the basal media tested for in vitro adventitious shoot production, resulting in significantly increased number of new microshoots/explant and higher shoots. 6-Benzyladenine (BA) at 2.5 μM increased shoot proliferation. The combination of α-Naphthaleneacetic acid (NAA) (1–2.5 μM) with BA (2.5 μM) had a positive influence at simultaneous proliferation and rooting resulting in high rooting percentage (82.5–95%) and increased number of roots. Rooting percentage reached 100% and number of roots increased significantly when 0.5 μM and 1 μM IBA was combined with ½MS and full strength MS. The in vitro response to salinity stress (0–300 mM NaCl) was also tested. Shoot proliferation was gradually reduced at higher concentrations of NaCl but shoot height was enhanced. Acclimatization procedure was successful.