The supermassive black hole in Centaurus A: a benchmark for gas kinematical measurements

We present new HST/STIS observations of Centaurus A. [SIII] 9533A was used to study the kinematics in the nuclear region with a 0.1" spatial resolution. The STIS data and the VLT/ISAAC spectra by Marconi et al. (2001) provide independent and consistent measures of the BH mass, which are in agreement with our previous estimate based on the ISAAC data alone: MBH=(1.1+/-0.1) 10^8 Msun for a disk inclination of i=25deg or or MBH=(6.5+/-0.7) 10^7 Msun for i=35deg, the largest i value allowed by the data. We find that the choice of the intrinsic surface brightness distribution, a crucial element in the modeling, has no effects on MBH but has a large impact on the gas velocity dispersion. A mismatch between the observed and model velocity dispersion is not necessarily an indication of non-circular motions or kinematically hot gas, but is as easily due to an inaccurate computation arising from too course a model grid, or the adoption of an intrinsic brightness distribution which is too smooth. The observed velocity dispersion, line profiles and the higher order moments in the Hermite expansion, h_3 and h_4, are consistent with emission from a rotating disk. Results from gas kinematical estimate are in good agreement with a recent stellar dynamical estimate of MBH. The BH mass in Centaurus A agrees with the correlation with infrared luminosity and mass of the host spheroid but is not in disagreement with the stellar velocity dispersion if one takes into account the intrinsic scatter of the MBH-sigma correlation. Finally, using HST data we can constrain the size of any cluster of dark objects alternative to a BH to r<0.035" (~0.6pc). Thus Centaurus A ranks among the best cases for supermassive Black Holes in galactic nuclei. (ABRIDGED)Comment: Astronomy and Astrophysics in press; minor changes following referee repor

Novel opsin gene variation in large-bodied, diurnal lemurs

Some primate populations include both trichromatic and dichromatic (red-green colour blind) individuals due to allelic variation at the X-linked opsin locus. This polymorphic trichromacy is well described in day-active New World monkeys. Less is known about colour vision in Malagasy lemurs, but, unlike New World monkeys, only some day-active lemurs are polymorphic, while others are dichromatic. The evolutionary pressures underlying these differences in lemurs are unknown, but aspects of species ecology, including variation in activity pattern, are hypothesized to play a role. Limited data on X-linked opsin variation in lemurs make such hypotheses difficult to evaluate. We provide the first detailed examination of X-linked opsin variation across a lemur clade (Indriidae). We sequenced the X-linked opsin in the most strictly diurnal and largest extant lemur, Indri indri, and nine species of smaller, generally diurnal indriids (Propithecus). Although nocturnal Avahi (sister taxon to Propithecus) lacks a polymorphism, at least eight species of diurnal indriids have two or more X-linked opsin alleles. Four rainforest-living taxa-I. indri and the three largest Propithecus species-have alleles not previously documented in lemurs. Moreover, we identified at least three opsin alleles in Indri with peak spectral sensitivities similar to some New World monkeys

Variation in the Meaning of Alarm Calls in Verreaux’s and Coquerel’s Sifakas (Propithecus verreauxi, P. coquereli)

The comprehension and usage of primate alarm calls appear to be influenced by social learning. Thus, alarm calls provide flexible behavioral mechanisms that may allow animals to develop appropriate responses to locally present predators. To study this potential flexibility, we compared the usage and function of 3 alarm calls common to 2 closely related sifaka species (Propithecus verreauxi and P. coquereli), in each of 2 different populations with different sets of predators. Playback studies revealed that both species in both of their respective populations emitted roaring barks in response to raptors, and playbacks of this call elicited a specific anti-raptor response (look up and climb down). However, in Verreaux’s sifakas, tchi-faks elicited anti-terrestrial predator responses (look down, climb up) in the population with a higher potential predation threat by terrestrial predators, whereas tchi-faks in the other population were associated with nonspecific flight responses. In both populations of Coquerel’s sifakas, tchi-fak playbacks elicited anti-terrestrial predator responses. More strikingly, Verreaux’s sifakas exhibited anti-terrestrial predator responses after playbacks of growls in the population with a higher threat of predation by terrestrial predators, whereas Coquerel’s sifakas in the raptor-dominated habitat seemed to associate growls with a threat by raptors; the 2 other populations of each species associated a mild disturbance with growls. We interpret this differential comprehension and usage of alarm calls as the result of social learning processes that caused changes in signal content in response to changes in the set of predators to which these populations have been exposed since they last shared a common ancestor

On species delimitation: Yet another lemur species or just genetic variation?

<p>Abstract</p> <p>Background</p> <p>Although most taxonomists agree that species are independently evolving metapopulation lineages that should be delimited with several kinds of data, the taxonomic practice in Malagasy primates (Lemuriformes) looks quite different. Several recently described lemur species are based solely on evidence of genetic distance and diagnostic characters of mitochondrial DNA sequences sampled from a few individuals per location. Here we explore the validity of this procedure for species delimitation in lemurs using published sequence data.</p> <p>Results</p> <p>We show that genetic distance estimates and <it>Population Aggregation Analysis </it>(PAA) are inappropriate for species delimitation in this group of primates. Intra- and interspecific genetic distances overlapped in 14 of 17 cases independent of the genetic marker used. A simulation of a fictive taxonomic study indicated that for the mitochondrial D-loop the minimum required number of individuals sampled per location is 10 in order to avoid false positives via PAA.</p> <p>Conclusions</p> <p>Genetic distances estimates and PAA alone should not be used for species delimitation in lemurs. Instead, several nuclear and sex-specific loci should be considered and combined with other data sets from morphology, ecology or behavior. Independent of the data source, sampling should be done in a way to ensure a quantitative comparison of intra- and interspecific variation of the taxa in question. The results of our study also indicate that several of the recently described lemur species should be reevaluated with additional data and that the number of good species among the currently known taxa is probably lower than currently assumed.</p

Structural Analysis of a Repetitive Protein Sequence Motif in Strepsirrhine Primate Amelogenin

Strepsirrhines are members of a primate suborder that has a distinctive set of features associated with the development of the dentition. Amelogenin (AMEL), the better known of the enamel matrix proteins, forms 90% of the secreted organic matrix during amelogenesis. Although AMEL has been sequenced in numerous mammalian lineages, the only reported strepsirrhine AMEL sequences are those of the ring-tailed lemur and galago, which contain a set of additional proline-rich tandem repeats absent in all other primates species analyzed to date, but present in some non-primate mammals. Here, we first determined that these repeats are present in AMEL from three additional lemur species and thus are likely to be widespread throughout this group. To evaluate the functional relevance of these repeats in strepsirrhines, we engineered a mutated murine amelogenin sequence containing a similar proline-rich sequence to that of Lemur catta. In the monomeric form, the MQP insertions had no influence on the secondary structure or refolding properties, whereas in the assembled form, the insertions increased the hydrodynamic radii. We speculate that increased AMEL nanosphere size may influence enamel formation in strepsirrhine primates

Comparing chromosomal and mitochondrial phylogenies of the Indriidae (Primates, Lemuriformes)

The Malagasy primate family Indriidae comprises three genera with up to 19 species. Cytogenetic and molecular phylogenies of the Indriidae have been performed with special attention to the genus Propithecus. Comparative R-banding and FISH with human paints were applied to karyotypes of representatives of all three genera and confirmed most of the earlier R-banding results. However, additional chromosomal rearrangements were detected. A reticulated and a cladistic phylogeny, the latter including hemiplasies, have been performed. Cladistic analysis of cytogenetic data resulted in a phylogenetic tree revealing (1) monophyly of the family Indriidae, (2) monophyly of the genus Avahi, (3) sister–group relationships between Propithecus diadema and Propithecus edwardsi, and (4) the grouping of the latter with Indri indri, Propithecus verreauxi, and Propithecus tattersalli, and thus suggesting paraphyly of the genus Propithecus. A molecular phylogeny based on complete mitochondrial cytochrome b sequences of 16 species indicated some identical relationships, such as the monophyly of Avahi and the sister–group relationships of the eastern (P. diadema and P. edwardsi) to the western Propithecus species (P. verreauxi, Propithecus coquereli, and P. tattersalli). However, the main difference between the molecular and cytogenetic phylogenies consists in an early divergence of Indri in the molecular phylogeny while in the chromosomal phylogeny it is nested within Propithecus. The similarities and differences between molecular and cytogenetic phylogenies in relation to data on the species’ geographic distributions and mating systems allow us to propose a scenario of the evolution of Indriidae. Chromosomal and molecular processes alone or in combination created a reproductive barrier that was then followed by further speciation processes

Role of retinoic receptors in lung carcinogenesis

Several in vitro and in vivo studies have examined the positive and negative effects of retinoids (vitamin A analogs) in premalignant and malignant lesions. Retinoids have been used as chemopreventive and anticancer agents because of their pleiotropic regulator function in cell differentiation, growth, proliferation and apoptosis through interaction with two types of nuclear receptors: retinoic acid receptors and retinoid X receptors. Recent investigations have gradually elucidated the function of retinoids and their signaling pathways and may explain the failure of earlier chemopreventive studies

Communication and visiting policies in Italian intensive care units during the first COVID-19 pandemic wave and lockdown: a nationwide survey

Background: During the first coronavirus disease 2019 (COVID-19) pandemic wave, an unprecedented number of patients with respiratory failure due to a new, highly contagious virus needed hospitalization and intensive care unit (ICU) admission. The aim of the present study was to describe the communication and visiting policies of Italian intensive care units (ICUs) during the first COVID-19 pandemic wave and national lockdown and compare these data with prepandemic conditions. Methods: A national web-based survey was conducted among 290 Italian hospitals. Each ICU (active between February 24 and May 31, 2020) was encouraged to complete an individual questionnaire inquiring the hospital/ICU structure/organization, communication/visiting habits and the role of clinical psychology prior to, and during the first COVID-19 pandemic wave. Results: Two hundred and nine ICUs from 154 hospitals (53% of the contacted hospitals) completed the survey (202 adult and 7 pediatric ICUs). Among adult ICUs, 60% were dedicated to COVID-19 patients, 21% were dedicated to patients without COVID-19 and 19% were dedicated to both categories (Mixed). A total of 11,102 adult patients were admitted to the participating ICUs during the study period and only approximately 6% of patients received at least one visit. Communication with family members was guaranteed daily through an increased use of electronic devices and was preferentially addressed to the same family member. Compared to the prepandemic period, clinical psychologists supported physicians more often regarding communication with family members. Fewer patients received at least one visit from family members in COVID and mixed-ICUs than in non-COVID ICUs, l (0 [0–6]%, 0 [0–4]% and 11 [2–25]%, respectively, p &lt; 0.001). Habits of pediatric ICUs were less affected by the pandemic. Conclusions: Visiting policies of Italian ICUs dedicated to adult patients were markedly altered during the first COVID-19 wave. Remote communication was widely adopted as a surrogate for family meetings. New strategies to favor a family-centered approach during the current and future pandemics are warranted