Homo sapiens in the Americas. Overview of the earliest human expansion in the new world

Although it is widely recognised that America was the last continent to be populated by our species, researchers' views on various aspects of this process (e.g. the period in which it occurred, the area from which the colonizing populations came, the number of dispersal waves and the routes taken by these migrations) differ significantly. In this paper, we review both classical data and more recent findings from various research fields - including geology, paleoecology, archaeology, skeletal biology, and genetics - that may shed light on the dynamics of the colonization of the American continent, according to a critical reappraisal of the various hypotheses and models that have been advanced over time to explain this process

Parasitic helminths induce fetal-like reversion in the intestinal stem cell niche.

Epithelial surfaces form critical barriers to the outside world and are continuously renewed by adult stem cells1. Whereas dynamics of epithelial stem cells during homeostasis are increasingly well understood, how stem cells are redirected from a tissue-maintenance program to initiate repair after injury remains unclear. Here we examined infection by Heligmosomoides polygyrus, a co-evolved pathosymbiont of mice, to assess the epithelial response to disruption of the mucosal barrier. H. polygyrus disrupts tissue integrity by penetrating the duodenal mucosa, where it develops while surrounded by a multicellular granulomatous infiltrate2. Crypts overlying larvae-associated granulomas did not express intestinal stem cell markers, including Lgr53, in spite of continued epithelial proliferation. Granuloma-associated Lgr5- crypt epithelium activated an interferon-gamma (IFN-γ)-dependent transcriptional program, highlighted by Sca-1 expression, and IFN-γ-producing immune cells were found in granulomas. A similar epithelial response accompanied systemic activation of immune cells, intestinal irradiation, or ablation of Lgr5+ intestinal stem cells. When cultured in vitro, granuloma-associated crypt cells formed spheroids similar to those formed by fetal epithelium, and a sub-population of H. polygyrus-induced cells activated a fetal-like transcriptional program, demonstrating that adult intestinal tissues can repurpose aspects of fetal development. Therefore, re-initiation of the developmental program represents a fundamental mechanism by which the intestinal crypt can remodel itself to sustain function after injury

Effect of sugars on Chlamydia trachomatis infectivity

Background. Previous works suggest that sugars can have a beneficial effect on C. trachomatis (CT) survival and virulence. In this study, we investigated the effect of different sugars on CT infectivity, elucidating some of the molecular mechanisms behind CT-sugar interaction. Methods. CT infectivity was investigated on HeLa cells after 2 hour-incubation of elementary bodies (EBs) with glucose, sucrose, or mannitol solutions (0.5, 2.5, 5.0 mM). The effect of sugars on EB membrane fluidity was investigated by fluorescence anisotropy measurement, whereas the changes in lipopolysaccharide (LPS) exposure were examined by cytofluorimetric analysis. By means of a Western blot, we explored the phosphorylation state of Focal Adhesion Kinase (FAK) in HeLa cells infected with EBs pre-incubated with sugars. Results. All sugar solutions significantly increased CT infectivity on epithelial cells, acting directly on the EB structure. Sugars induced a significant increase of EB membrane fluidity, leading to changes in LPS membrane exposure. Especially after incubation with sucrose and mannitol, EBs led to a higher FAK phosphorylation, enhancing the activation of anti-apoptotic and proliferative signals in the host cells. Conclusions. Sugars can increase CT infectivity and virulence, by modulating the expression/exposure of chlamydial membrane ligands. Further in-depth studies are needed to better understand the molecular mechanisms involved

Mosaic structure of the penA gene in the oropharynx of men who have sex with men negative for gonorrhoea

The oropharynx represents a crucial site for the emergence of multi-drug resistance in Neisseria gonorrhoeae. The mosaic penA alleles, associated with decreased susceptibility to cephalosporins, have emerged by DNA recombination with partial penA genes, particularly those from commensal pharyngeal Neisseria species. Here, we investigated the prevalence of the mosaic structure of the penA gene in the oropharynx of men who have sex with men testing negative for pharyngeal gonorrhoea. From January 2016 to June 2018, 351 gonorrhoea-negative men who have sex with men attending a sexually transmitted infection clinic in Italy were enrolled. Pharyngeal swabs underwent a real-time polymerase chain reaction (PCR) for the detection of the mosaic penA gene. In case of positivity, PCR products were sequenced and searched against several sequences of Neisseria strains. Overall, 31 patients (8.8%) were found positive for the presence of the mosaic penA gene. The positivity was significantly associated with previous cases of pharyngeal gonorrhoea (relative risk [RR]: 3.56, 95% confidence interval 1.44\u20138.80) and with recent exposure to beta-lactams (RR: 4.29, 95% confidence interval 2.20\u20138.38). All penA-positive samples showed a high relatedness (90\u201399%) with mosaic-positive Neisseria strains. Our data underline that commensal Neisseria species of the oropharynx may be a significant reservoir for genetic material conferring antimicrobial resistance in N. gonorrhoeae

Role of poultry meat in a balanced diet aimed at maintaining health and wellbeing: an Italian consensus document

The relationship between the consumption of meat and health is multifaceted, and it needs to be analyzed in detail, with specific attention to the relevant differences that characterize the effects of the different meat types, as yet considered by only a limited literature. A variable but moderate energy content, highly digestible proteins (with low levels of collagen) of good nutritional quality, unsaturated lipids (mainly found in the skin and easily removed), B-group vitamins (mainly thiamin, vitamin B6, and pantothenic acid), and minerals (like iron, zinc, and copper) make poultry meat a valuable food. Epidemiological studies performed across the world, in highly diverse populations with different food preferences and nutritional habits, provide solid information on the association between poultry consumption, within a balanced diet, and good health. Consumption of poultry meat, as part of a vegetable-rich diet, is associated with a risk reduction of developing overweight and obesity, cardiovascular diseases, and type 2 diabetes mellitus. Also, white meat (and poultry in particular) is considered moderately protective or neutral on cancer risk. The relevance of poultry meat for humans also has been recognized by the UN Food and Agricultural Organization (FAO), who considers this widely available, relatively inexpensive food to be particularly useful in developing countries, where it can help to meet shortfalls in essential nutrients. Moreover, poultry meat consumption also contributes to the overall quality of the diet in specific ages and conditions (prior to conception, during pregnancy up to the end of breastfeeding, during growth, and in the geriatric age) and is suitable for those who have an increased need for calorie and protein compared to the general population

Meningococcal Carriage in ‘Men Having Sex With Men’ With Pharyngeal Gonorrhoea

We assessed the characteristics of Neisseria meningitidis pharyngeal carriage in a cohort of ‘men having sex with men’, including patients with pharyngeal Neisseria gonorrhoeae infection. In the period 2017-2019, among all the oropharyngeal samples tested for gonorrhoea from MSM attending a STI Clinic in Bologna (Italy), we randomly selected 244 N. gonorrhoeae-positive samples and 403 negatives (n=647). Pharyngeal specimens were tested for N. meningitidis presence, by the detection of sodC gene. N. meningitidis-positive samples were further grouped by PCR tests for the major invasive genogroups (i.e., A, B, C, W, and Y). A molecular assay, targeting capsule transporter gene, was used to determine meningococcal capsular status. Overall, 75.8% (491/647) of samples tested positive for sodC gene, indicating a pharyngeal meningococcal carriage. Meningococcal colonisation was significantly more frequent in younger subjects (P=0.009), with no association with HIV infection. Non-groupable meningococci represented most of pharyngeal carriages (about 71%). The commonest N. meningitidis serogroup was B (23.6%), followed by C (2.1%), Y (1.8%) and W (1.1%). Meningococci were often characterized by the genetic potential of capsule production. Interestingly, a negative association between N. meningitidis and N. gonorrhoeae was found: pharyngeal gonorrhoea was significantly more present in patients without meningococcal carriage (P=0.03). Although preliminary, our data added knowledge on the epidemiology of meningococcal carriage in MSM communities at high risk of gonococcal infections, gaining new insights into the interactions/dynamics between N. meningitidis and N. gonorrhoeae

Influence of the Location of the Internal Temperature Control Loop on the Performance of the Dual Temperature Control for Feed Temperature Disturbance

A control strategy with distributed corrective action for distillation has been proposed and consists of a conventional dual temperature control combined with an additional column tray. In this work, we evaluated the influence of the location of this internal loop as part of the new proposal, compared to a conventional system. Tests were carried out in a 13-column tray distillation equipment and feed temperature was disturbed. Two different column trays from the stripping section were used (11 and 12) for internal decentralized temperature control, each one separately, plus the dual control of top and bottom temperatures. The results demonstrated that this proposed control approach with distributed corrective action is faster than the conventional one, regardless of the column tray in use. It was also determined that the internal loop close to the feed (disturbance) is more interesting as a way to minimize transients

Antenatal syphilis serology in pregnant women and follow-up of their infants in northern Italy

ABSTRACTPositive syphilis serology was noted in 119 (0.49%) of the 24 053 pregnant women delivering at St Orsola Hospital in Bologna, Italy, from November 2000 through July 2007. Six presumptive cases of congenital syphilis with IgM western blot positive results were found. Two infants had a positive cerebrospinal fluid (CSF) Venereal Disease Research Laboratory test result (one also had a positive CSF PCR result), another presented long-bone lesions, and the remaining three were preterm. These observations confirmed that antenatal syphilis screening facilitates treatment during pregnancy and offsets vertical transmission; moreover, the use of IgM western blot and careful CSF examination allowed the identification and treatment of high-risk newborns

Vaginal and anal microbiome during chlamydia trachomatis infections

Background. Chlamydia trachomatis (CT) is the agent of the most common bacterial sexually transmitted infection worldwide, with a significant impact on women’s health. Despite the increasing number of studies about the vaginal microbiome in women with CT infections, information about the composition of the anal microbiome is still lacking. Here, we assessed the bacterial community profiles of vaginal and anal ecosystems associated or not with CT infection in a cohort of Caucasian young women. Methods. A total of 26 women, including 10 with a contemporary vaginal and anorectal CT infection, were enrolled. Composition of vaginal and anal microbiome was studied by 16S rRNA gene profiling. Co-occurrence networks of bacterial communities and metagenome metabolic functions were determined. Results. In case of CT infection, both vaginal and anal environments were characterized by a degree of dysbiosis. Indeed, the vaginal microbiome of CT-positive women were depleted in lactobacilli, with a significant increase in dysbiosis-associated bacteria (e.g., Sneathia, Parvimonas, Megasphaera), whereas the anal microbiota of CT-infected women was characterized by higher levels of Parvimonas and Pseudomonas and lower levels of Escherichia. Interestingly, the microbiome of anus and vagina had numerous bacterial taxa in common, reflecting a significant microbial ‘sharing’ between the two sites. In the vaginal environment, CT positively correlated with Ezakiella spp. while Gardnerella vaginalis co-occurred with several dysbiosis-related microbes, regardless of CT vaginal infection. The vaginal microbiome of CT-positive females exhibited a higher involvement of chorismate and aromatic amino acid biosynthesis, as well as an increase in mixed acid fermentation. Conclusions. These data could be useful to set up new diagnostic/prognostic tools, offering new perspectives for the control of chlamydial infections