The effect of the lunar cycle on fecal cortisol metabolite levels and foraging ecology of nocturnally and diurnally active spiny mice

We studied stress hormones and foraging of nocturnal Acomys cahirinus and diurnal A. russatus in field populations as well as in two field enclosures populated by both species and two field enclosures with individuals of A. russatus alone. When alone, A. russatus individuals become also nocturnally active. We asked whether nocturnally active A. russatus will respond to moon phase and whether this response will be obtained also in diurnally active individuals. We studied giving-up densities (GUDs) in artificial foraging patches and fecal cortisol metabolite levels. Both species exhibited elevated fecal cortisol metabolite levels and foraged to higher GUDs in full moon nights; thus A. russatus retains physiological response and behavioral patterns that correlate with full moon conditions, as can be expected in nocturnal rodents, in spite of its diurnal activity. The endocrinological and behavioral response of this diurnal species to moon phase reflects its evolutionary heritage.     

Genomic polymorphism of the pandemic A (H1N1) influenza viruses correlates with viral replication, virulence, and pathogenicity in vitro and in vivo

The novel pandemic A (H1N1) virus was first identified in Mexico in April 2009 and quickly spread worldwide. Like all influenzas, the H1N1 strain-specific properties of replication, virulence, and pathogenicity are a result of the particular genomic sequence and concerted expression of multiple genes. Thus, specific mutations may support increased virulence and may be useful as biomarkers of potential threat to human health. We performed comparative genomic analysis of ten strains of the 2009 pandemic A (H1N1) influenza viruses to determine whether genotypes associated with clinical phenotypes, which ranged from mild to severe illness and up to lethal. Virus replication capacity was tested for each strain in vitro using cultured epithelial cells, while virulence and pathogenicity were investigated in vivo using the BALB/c mouse model. The results indicated that A/Sichuan/1/2009 strain had significantly higher replication ability and virulence than the other strains, and five unique non-synonymous mutations were identified in important gene-encoding sequences. These mutations led to amino acid substitutions in HA (L32I), PA (A343T), PB1 (K353R and T566A), and PB2 (T471M), and may be critical molecular determinants for replication, virulence, and pathogenicity. Our results suggested that the replication capacity in vitro and virulence in vivo of the 2009 pandemic A (H1N1) viruses were not associated with the clinical phenotypes. This study offers new insights into the transmission and evolution of the 2009 pandemic A (H1N1) virus.     

Body size of insular carnivores: little support for the island rule

Large mammals are thought to evolve to be smaller on islands, whereas small mammals grow larger. A negative correlation between relative size of island individuals and body mass is termed the "island rule." Several mechanisms--mainly competitive release, resource limitation, dispersal ability, and lighter predation pressure on islands, as well as a general physiological advantage of modal size--have been advanced to explain this pattern. We measured skulls and teeth of terrestrial members of the order Carnivora in order to analyze patterns of body size evolution between insular populations and their near mainland conspecifics. No correlations were found between the size ratios of insular/mainland carnivore species and body mass. Only little support for the island rule is found when individual populations rather than species are considered. Our data are at odds with those advanced in support of theories of optimal body size. Carnivore size is subjected to a host of selective pressures that do not vary uniformly from place to place. Mass alone cannot account for the patterns in body size of insular carnivores.     

Expression of cell-cycle regulator CDK2-associating protein 1 (p12CDK2AP1) in transgenic mice induces testicular and ovarian atrophy in vivo

The novel cell-cycle regulator p12(CDK2AP1) (p12) gene encodes a cyclin-dependent kinase 2 (CDK2) partner that participates in cell-cycle regulation, apoptosis, and proliferation. CDK2 has been implicated in maintenance of gonadal homeostasis, as knockout mice display reproductive abnormalities. To investigate the role of p12 in homeostasis of gonadal tissues in vivo, we generated a transgenic mouse model driven by the human keratin 14 promoter, reported to target transgene expression to gonadal tissues and also stratified epithelia. Overexpression of the transgene was associated with a gonadal atrophy phenotype in mice of both sexes, yet fertility was not impaired. Histological evaluation of testes showed seminiferous tubule degeneration and decreased tubule diameter. Female transgenic mice had small ovaries, with a higher number of atretic follicles/mm(2) as compared to control nontransgenic mice. Also observed was increased germ cell apoptosis in both sexes (TUNEL). These results suggest that overexpression of p12 leads to testicular and ovarian abnormalities, a phenotype closely related to that of cdk2-/- mice. In combination, these observations suggest that the p12/CDK2 signaling pathways are carefully orchestrated to maintain proper gonadal tissue homeostasis. We suggest that the mechanisms of this regulation may be through p12-mediated altered expression of gonadal-specific genes and apoptotic pathways.     

Synthesis, crystal structure, spectral properties and catalytic activity of hexakis(imidazole)manganese(II) bisindole-2-carboxylato bisneocuproine bisdimethyl sulfoxide solvates {[Mn(Im)6] · 2(2-IC) · 2(NC) · 2(DMSO)}

Synthesis, X-ray crystal structure and IR spectrum of {[Mn^II(Im)₆] · 2(2-IC) · 2(NC) · 2(DMSO)} (Im = imidazole, 2-HIC = indole-2-carboxylic acid, NC = 2,9-dimethyl-1,10-phenanthroline, DMSO = dimethyl sulfoxide) are reported. The manganese(II) ion has octahedral geometry with a MnN₆ core. The crystal structure is completed by two NC, two 2-IC⁻ and two DMSO solvate molecules. The individual cations are linked into chains running parallel to the a axis by four intermolecular hydrogen bonding involving two 2-IC⁻solvate. Moreover, these chains are connected by π-π stacking interactions which occur between neocuproine molecules related through inversion center. In IR spectroscopy, the compound spectrum is roughly similar to the imidazole one: (i) above 1800 cm⁻¹, the bands are broad, but when focussing on some of them a doublet structure can be found; (ii) below 1800 cm⁻¹, the bands are sharp and it is then possible to point out the modification of S-O band when this later is involved in bifurcated hydrogen bonding to a second solvate 2-IC⁻. The compound catalyses the disproportionation of H₂O₂; moreover an additional quantity of imidazole increases the reaction rate.     

E-cadherin in oral SCC: an analysis of the confusing literature and new insights related to its immunohistochemical expression

E-cadherin plays a crucial structural role in cell-cell contacts in epithelial tissues, and a functional role in signaling pathways that regulate cell proliferation, differentiation, and survival. Reduced immunoexpression of E-cadherin adhesions is largely considered as being equivalent to defective functionality and malignancy, and has been used as a prognostic parameter. A critical analysis of studies on E-cadherin immunoexpression in oral carcinomas revealed a wide range of both technical and interpretational aspects. This paper highlights biological characteristics of E-cadherin with respect to its expression in normal and neoplastic epithelial cells and to its interrelations with the tumor microenvironment that can have an impact on immunohistochemical results and their application in the clinical setting.     

Leaf-induced gibberellin signaling is essential for internode elongation, cambial activity, and fiber differentiation in tobacco stems

The gibberellins (GAs) are a group of endogenous compounds that promote the growth of most plant organs, including stem internodes. We show that in tobacco (Nicotiana tabacum) the presence of leaves is essential for the accumulation of bioactive GAs and their immediate precursors in the stem and consequently for normal stem elongation, cambial proliferation, and xylem fiber differentiation. These processes do not occur in the absence of maturing leaves but can be restored by application of C(19)-GAs, identifying the presence of leaves as a requirement for GA signaling in stems and revealing the fundamental role of GAs in secondary growth regulation. The use of reporter genes for GA activity and GA-directed DELLA protein degradation in Arabidopsis thaliana confirms the presence of a mobile signal from leaves to the stem that induces GA signaling.