Sexual signalling in Propithecus verreauxi: male "chest badge" and female mate choice

Communication, an essential prerequisite for sociality, involves the transmission of signals. A signal can be defined as any action or trait produced by one animal, the sender, that produces a change in the behaviour of another animal, the receiver. Secondary sexual signals are often used for mate choice because they may inform on a potential partner's quality. Verreaux's sifaka (Propithecus verreauxi) is characterized by the presence of two different morphs of males (bimorphism), which can show either a stained or clean chest. The chest becomes stained by secretions of the sternal gland during throat marking (rubbing throat and chest on a vertical substrate while smearing the scent deposition). The role of the chest staining in guiding female mate choice was previously hypothesized but never demonstrated probably due to the difficulty of observing sifaka copulations in the wild. Here we report that stained-chested males had a higher throat marking activity than clean-chested males during the mating season, but not during the birth season. We found that females copulated more frequently with stained-chested males than the clean-chested males. Finally, in agreement with the biological market theory, we found that clean-chested males, with a lower scent-releasing potential, offered more grooming to females. This "grooming for sex" tactic was not completely unsuccessful; in fact, half of the clean-chested males copulated with females, even though at low frequency. In conclusion, the chest stain, possibly correlated with different cues targeted by females, could be one of the parameters which help females in selecting mates.     

Growth Factors and Steroid Mediated Regulation of Cytoskeletal Protein Expression in Serum-Deprived Primary Astrocyte Cultures

In this research we aimed to investigate the interactions between growth factors (GFs) and dexamethasone (DEX) on cytoskeletal proteins GFAP and vimentin (VIM) expression under different experimental conditions. Condition I: 24 h pretreatment with bFGF, subsequent 72 h switching in serum-free medium (SFM) and final addition of GFs, alone or by two in the last 24 h, after a prolonged (60 h) DEX treatment. Condition II: 36 h pretreatment with DEX (with bFGF in the last 24 h), followed by SFM for 60 h and final addition for 24 h with growth factors alone or two of them togheter. Western blot analysis data showed a marked GFAP expression in cultures submitted to Condition I comparing results to untreated or treated controls. VIM expression was instead significantly reduced after GFs addition in the last 24 h of 60 h DEX treatment, respect to control DEX-pretreated ones. Referring data to untreated controls, VIM expression was significantly enhanced after GFs addition. GFAP showed also a significant increase in astrocytes submitted to Condition II, respect to untreated or treated control cultures. VIM expression was up and down regulated under Condition II. Collectively, our findings evidence an interactive dialogue between GFs and DEX in astroglial cultures, co-pretreated with DEX and bFGF, regulating cytoskeletal network under stressfull conditions. Special issue article in honor of Dr. Anna Maria Giuffrida-Stella.     

Three new species of Croton (Euphorbiaceae s.s.) from the Brazilian Caatinga

While conducting a floristic inventory of Croton from the Brazilian Caatinga, three new species were discovered. Croton arenosus, Croton glandulosobracteatus, and Croton harleyi are described and illustrated here. Based on morphological characters, Croton glandulosobracteatus is proposed to belong to section Barhamia, and C. arenosus and C. harleyi to section Geiseleria.     

Biotransformation and reduction of estrogenicity of bisphenol A by the biphenyl-degrading Cupriavidus basilensis

The biphenyl-degrading Gram-negative bacterium Cupriavidus basilensis (formerly Ralstonia sp.) SBUG 290 uses various aromatic compounds as carbon and energy sources and has a high capacity to transform bisphenol A (BPA), which is a hormonally active substance structurally related to biphenyl. Biphenyl-grown cells initially hydroxylated BPA and converted it to four additional products by using three different transformation pathways: (a) formation of multiple hydroxylated BPA, (b) ring fission, and (c) transamination followed by acetylation or dimerization. Products of the ring fission pathway were non-toxic and all five products exhibited a significantly reduced estrogenic activity compared to BPA. Cell cultivation with phenol and especially in nutrient broth (NB) resulted in a reduced biotransformation rate and lower product quantities, and NB-grown cells did not produce all five products in detectable amounts. Thus, the question arose whether enzymes of the biphenyl degradation pathway are involved in the transformation of BPA and was addressed by proteomic analyses.

     

Enzymes that hydrolyze adenine nucleotides of patients with hypercholesterolemia and inflammatory processes

The activity of NTPDase (EC 3.6.1.5, apyrase, CD39) was verified in platelets from patients with increasing cholesterol levels. A possible association between cholesterol levels and inflammatory markers, such as oxidized low-density lipoprotein, highly sensitive C-reactive protein and oxidized low-density lipoprotein autoantibodies, was also investigated. Lipid peroxidation was estimated by measurement of thiobarbituric acid reactive substances in serum. The following groups were studied: group I, < 150 mg.dL(-1) cholesterol; group II, 151-200 mg.dL(-1) cholesterol; group III, 201-250 mg.dL(-1) cholesterol; and group IV, > 251 mg.dL(-1) cholesterol. The results demonstrated that both ATP hydrolysis and ADP hydrolysis were enhanced as a function of cholesterol level. Low-density lipoprotein levels increased concomitantly with total cholesterol levels. Triglyceride levels were increased in the groups with total cholesterol above 251 mg.dL(-1). Oxidized low-density lipoprotein levels were elevated in groups II, III, and IV. Highly sensitive C-reactive protein was elevated in the group with cholesterol levels higher than 251 mg.dL(-1). Oxidized low-density lipoprotein autoantibodies were elevated in groups III and IV. Thiobarbituric acid reactive substance content was enhanced as a function of cholesterol level. In summary, hypercholesterolemia is associated with enhancement of inflammatory response, oxidative stress, and ATP and ADP hydrolysis. The increased ATP and ADP hydrolysis in group IV was confirmed by an increase in CD39 expression on its surface. The increase in CD39 activity is possibly related to a compensatory response to the inflammatory and pro-oxidative state associated with hypercholesterolemia.     

Glucomannan-mediated attachment of Rhizobium leguminosarum to pea root hairs is required for competitive nodule infection

The Rhizobium leguminosarum biovar viciae genome contains several genes predicted to determine surface polysaccharides. Mutants predicted to affect the initial steps of polysaccharide synthesis were identified and characterized. In addition to the known cellulose (cel) and acidic exopolysaccharide (EPS) (pss) genes, we mutated three other loci; one of these loci (gmsA) determines glucomannan synthesis and one (gelA) determines a gel-forming polysaccharide, but the role of the other locus (an exoY-like gene) was not identified. Mutants were tested for attachment and biofilm formation in vitro and on root hairs; the mutant lacking the EPS was defective for both of these characteristics, but mutation of gelA or the exoY-like gene had no effect on either type of attachment. The cellulose (celA) mutant attached and formed normal biofilms in vitro, but it did not form a biofilm on root hairs, although attachment did occur. The cellulose-dependent biofilm on root hairs appears not to be critical for nodulation, because the celA mutant competed with the wild-type for nodule infection. The glucomannan (gmsA) mutant attached and formed normal biofilms in vitro, but it was defective for attachment and biofilm formation on root hairs. Although this mutant formed nodules on peas, it was very strongly outcompeted by the wild type in mixed inoculations, showing that glucomannan is critical for competitive nodulation. The polysaccharide synthesis genes around gmsA are highly conserved among other rhizobia and agrobacteria but are absent from closely related bacteria (such as Brucella spp.) that are not normally plant associated, suggesting that these genes may play a wide role in bacterium-plant interactions.     

Interaction between ephrins/Eph receptors and excitatory amino acid receptors: possible relevance in the regulation of synaptic plasticity and in the pathophysiology of neuronal degeneration

There is increasing evidence that Eph receptors and their transmembrane ligands, named ephrins, interact with glutamate receptors in both developing and adult neurons. EphB receptors interact with proteins that regulate the membrane trafficking of alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA) receptor subunits, and both ephrins and EphB receptors have been found to co-localize with N-methyl-d-aspartate (NMDA) receptors and to positively modulate NMDA receptor function. Moreover, pharmacologic activation of ephrin-Bs amplifies group-I metabotropic glutamate receptor signaling through mechanisms that involve NMDA receptors. The interaction with ionotropic or metabotropic glutamate receptors provides a substrate for the emerging role of ephrins and Eph receptors in the regulation of activity-dependent forms of synaptic plasticity, such as long-term potentiation and long-term depression, which are established electrophysiologic models of associative learning. In addition, these interactions explain the involvement of ephrins/Eph receptors in the regulation of pain threshold and epileptogenesis, as well as their potential implication in processes of neuronal degeneration. This may stimulate the search for new drugs that might modulate excitatory synaptic transmission by interacting with the ephrin/Eph receptor system.     

Quantitative Timed-Up-and-Go Parameters in Relation to Cognitive Parameters and Health-Related Quality of Life in Mild-to-Moderate Parkinson's Disease

IntroductionThe instrumented-Timed-Up-and-Go test (iTUG) provides detailed information about the following movement patterns: sit-to-walk (siwa), straight walking, turning and walk-to-sit (wasi). We were interested in the relative contributions of respective iTUG sub-phases to specific clinical deficits most relevant for daily life in Parkinson’s disease (PD). More specifically, we investigated which condition–fast speed (FS) or convenient speed (CS)–differentiates best between mild- to moderate-stage PD patients and controls, which parameters of the iTUG sub-phases are significantly different between PD patients and controls, and how the iTUG parameters associate with cognitive parameters (with particular focus on cognitive flexibility and working memory) and Health-Related-Quality of Life (HRQoL).MethodsTwenty-eight PD participants (65.1±7.1 years, H&Y stage 1–3, medication OFF state) and 20 controls (66.1±7.5 years) performed an iTUG (DynaPort^®, McRoberts BV, The Netherlands) under CS and FS conditions. The PD Questionnaire 39 (PDQ-39) was employed to assess HRQoL. General cognitive and executive functions were assessed using the Montreal Cognitive Assessment and the Trail Making Test.ResultsThe total iTUG duration and sub-phases durations under FS condition differentiated PD patients slightly better from controls, compared to the CS condition. The following sub-phases were responsible for the observed longer total duration PD patients needed to perform the iTUG: siwa, turn and wasi. None of the iTUG parameters correlated relevantly with general cognitive function. Turning duration and wasi maximum flexion velocity correlated strongest with executive function. Walking back duration correlated strongest with HRQoL.DiscussionThis study confirms that mild- to moderate-stage PD patients need more time to perform the iTUG than controls, and adds the following aspects to current literature: FS may be more powerful than CS to delineate subtle movement deficits in mild- to moderate-stage PD patients; correlation levels of intra-individual siwa and wasi parameters may be interesting surrogate markers for the level of automaticity of performed movements; and sub-phases and kinematic parameters of the iTUG may have the potential to reflect executive functioning and HRQoL aspects of PD patients.