Modification of phosphoinositides by the Shigella effector IpgD during host cell infection.

Shigella, the causative agent of bacillary dysentery, subvert cytoskeletal and trafficking processes to invade and replicate in epithelial cells using an arsenal of bacterial effectors translocated through a type III secretion system. Here, we review the various roles of the type III effector IpgD, initially characterized as phosphatidylinositol 4,5 bisphosphate (PI4,5P2) 4-phosphatase. By decreasing PI4,5P2 levels, IpgD triggers the disassembly of cortical actin filaments required for bacterial invasion and cell migration. PI5P produced by IpgD further stimulates signaling pathways regulating cell survival, macropinosome formation, endosomal trafficking and dampening of immune responses. Recently, IpgD was also found to exhibit phosphotransferase activity leading to PI3,4P2 synthesis adding a new flavor to this multipotent bacterial enzyme. The substrate of IpgD, PI4,5P2 is also the main substrate hydrolyzed by endogenous phospholipases C to produce inositoltriphosphate (InsP3), a major Ca2+ second messenger. Hence, beyond the repertoire of effects associated with the direct diversion of phoshoinositides, IpgD indirectly down-regulates InsP3-mediated Ca2+ release by limiting InsP3 production. Furthermore, IpgD controls the intracellular lifestyle of Shigella promoting Rab8/11 -dependent recruitment of the exocyst at macropinosomes to remove damaged vacuolar membrane remnants and promote bacterial cytosolic escape. IpgD thus emerges as a key bacterial effector for the remodeling of host cell membranes.

α-Synuclein fibrils subvert lysosome structure and function for the propagation of protein misfolding between cells through tunneling nanotubes.

The accumulation of α-synuclein (α-syn) aggregates in specific brain regions is a hallmark of synucleinopathies including Parkinson disease (PD). α-Syn aggregates propagate in a "prion-like" manner and can be transferred inside lysosomes to recipient cells through tunneling nanotubes (TNTs). However, how lysosomes participate in the spreading of α-syn aggregates is unclear. Here, by using super-resolution (SR) and electron microscopy (EM), we find that α-syn fibrils affect the morphology of lysosomes and impair their function in neuronal cells. In addition, we demonstrate that α-syn fibrils induce peripheral redistribution of lysosomes, likely mediated by transcription factor EB (TFEB), increasing the efficiency of α-syn fibrils' transfer to neighboring cells. We also show that lysosomal membrane permeabilization (LMP) allows the seeding of soluble α-syn in cells that have taken up α-syn fibrils from the culture medium, and, more importantly, in healthy cells in coculture, following lysosome-mediated transfer of the fibrils. Moreover, we demonstrate that seeding occurs mainly at lysosomes in both donor and acceptor cells, after uptake of α-syn fibrils from the medium and following their transfer, respectively. Finally, by using a heterotypic coculture system, we determine the origin and nature of the lysosomes transferred between cells, and we show that donor cells bearing α-syn fibrils transfer damaged lysosomes to acceptor cells, while also receiving healthy lysosomes from them. These findings thus contribute to the elucidation of the mechanism by which α-syn fibrils spread through TNTs, while also revealing the crucial role of lysosomes, working as a Trojan horse for both seeding and propagation of disease pathology.

Transcytosis subversion by M cell-to-enterocyte spread promotes Shigella flexneri and Listeria monocytogenes intracellular bacterial dissemination.

Microfold (M) cell host-pathogen interaction studies would benefit from the visual analysis of dynamic cellular and microbial interplays. We adapted a human in vitro M cell model to physiological bacterial infections, expression of fluorescent localization reporters and long-term three-dimensional time-lapse microscopy. This approach allows following key steps of M cell infection dynamics at subcellular resolution, from the apical onset to basolateral epithelial dissemination. We focused on the intracellular pathogen Shigella flexneri, classically reported to transcytose through M cells to initiate bacillary dysentery in humans, while eliciting poorly protective immune responses. Our workflow was critical to reveal that S. flexneri develops a bimodal lifestyle within M cells leading to rapid transcytosis or delayed vacuolar rupture, followed by direct actin motility-based propagation to neighboring enterocytes. Moreover, we show that Listeria monocytogenes, another intracellular pathogen sharing a tropism for M cells, disseminates in a similar manner and evades M cell transcytosis completely. We established that actin-based M cell-to-enterocyte spread is the major dissemination pathway for both pathogens and avoids their exposure to basolateral compartments in our system. Our results challenge the notion that intracellular pathogens are readily transcytosed by M cells to inductive immune compartments in vivo, providing a potential mechanism for their ability to evade adaptive immunity.

Revisiting traumatic injury risk and agricultural intensification: Postcranial fracture frequency at Cerro Oreja in the Moche Valley of north coastal Peru.

OBJECTIVES: In Lambert and Welker (2017) we explored the association between subsistence economy and postcranial fracture prevalence, finding that low-intensity agriculturalists exhibited significantly lower fracture rates than foragers or high-intensity agriculturalists. Here, we explore the impacts of sampling strategy on fracture rates in a sample of high-intensity agriculturalists from the Moche Valley, Peru, and further test the hypothesis that postcranial fracture risks are higher for intensive agriculture. MATERIALS AND METHODS: The long bones and clavicles of 102 individuals from an Early Intermediate Period cemetery (400 B.C.-A.D. 200) at Cerro Oreja were examined for healed fractures. Sample composition was manipulated in six ways to investigate the effects of age and element completeness on estimates of fracture prevalence. Fracture rates at Cerro Oreja were then compared to those for other high-intensity agriculturalists. RESULTS: Both skeletal element completeness and age composition were found to influence fracture rate estimates, reflecting the greater likelihood of identifying healed fractures on better-preserved bones and the accrual of injuries with age. The fracture rate of 3.4% at Cerro Oreja was the median value among seven high-intensity agriculturalist samples. The fracture distribution at Cerro Oreja was most similar to that observed at Kulubnarti, Sudan (Kilgore et al., 1997). DISCUSSION: Skeletal element completeness and age composition can impact fracture rates estimated for skeletal samples and should be considered when conducting comparative analyses. All rates calculated for Cerro Oreja are within the range of those obtained for other high-intensity agriculturalists and support previous findings that traumatic injury risk is higher for high-intensity agriculturalists. Similarities between Cerro Oreja and Kulubnarti suggest that rugged terrain may exacerbate fracture risk for agriculturalists, illustrating the costs of intensive agriculture in suboptimal environments.

The entry of Salmonella in a distinct tight compartment revealed at high temporal and ultrastructural resolution.

Salmonella enterica induces membrane ruffling and genesis of macropinosomes during its interactions with epithelial cells. This is achieved through the type three secretion system-1, which first mediates bacterial attachment to host cells and then injects bacterial effector proteins to alter host behaviour. Next, Salmonella enters into the targeted cell within an early membrane-bound compartment that matures into a slow growing, replicative niche called the Salmonella Containing Vacuole (SCV). Alternatively, the pathogen disrupts the membrane of the early compartment and replicate at high rate in the cytosol. Here, we show that the in situ formed macropinosomes, which have been previously postulated to be relevant for the step of Salmonella entry, are key contributors for the formation of the mature intracellular niche of Salmonella. We first clarify the primary mode of type three secretion system-1 induced Salmonella entry into epithelial cells by combining classical fluorescent microscopy with cutting edge large volume electron microscopy. We observed that Salmonella, similarly to Shigella, enters epithelial cells inside tight vacuoles rather than in large macropinosomes. We next apply this technology to visualise rupturing Salmonella containing compartments, and we use extended time-lapse microscopy to establish early markers that define which Salmonella will eventually hyper replicate. We show that at later infection stages, SCVs harbouring replicating Salmonella have previously fused with the in situ formed macropinosomes. In contrast, such fusion events could not be observed for hyper-replicating Salmonella, suggesting that fusion of the Salmonella entry compartment with macropinosomes is the first committed step of SCV formation.

Avaliação do fluxo salivar e capacidade tampão da saliva de pacientes psiquiátricos em uso de agentes psicotrópicos / Evaluation salivary flow rate and buffer capacity of psychiatric patients using psychotropic agents

Introdução: os transtornos psiquiátricos são considerados um problema de saúde pública, pois cerca de 450 milhões de pessoas no mundo desenvolveram algum tipo de desordem mental ou transtorno psicossocial. Doenças psiquiátricas crônicas necessitam do uso permanente e prolongado de medicamentos que podem causar efeitos colaterais na cavidade bucal, como xerostomia e diminuição da velocidade e/ou alteração do fluxo salivar. Esses eventos podem levar ao aumento de cárie e da doença periodontal. A saliva, além da função de limpar a cavidade bucal, ajuda na digestão, mastigação, deglutição, fala e lubrificação, desempenhando um importante papel para a saúde bucal. Objetivo: este trabalho tem como objetivo avaliar o fluxo salivar e a capacidade tampão de pacientes com transtornos mentais em uso de agentes psicotrópicos, acompanhados nos serviços de Psiquiatria do Hospital Universitário Professor Edgard Santos, da Universidade Federal da Bahia. Metodologia: a saliva estimulada de 18 pacientes que participaram deste estudo foi coletada através da mastigação de um Parafilm®, durante cinco minutos. Resultados: a depressão foi a doença mais comum, os medicamentos mais utilizados foram a Risperidona e o Clonazepam e a hipossalivação apareceu em 44,44% dos pacientes. Não houve alteração na capacidade tampão da saliva. A xerostomia foi referida em 72,2% da amostra e foi frequente em 100% das pessoas com hipossalivação. Conclusão: os pacientes psiquiátricos merecem atenção especial, bem como são necessários estudos comparativos e longitudinais para obtenção de uma relação de causalidade.

Introduction: psychiatric disorders are considered a public health problem because nearly 450 million people worldwide have developed some form of mental or psychosocial disorder. Chronic psychiatric diseases require the permanent and prolonged use of medications, which can cause side effects in the oral cavity, such as xerostomia and a reduction and / or alteration in the speed of the salivary flow. These events can lead to an increase in caries as well as in periodontal disease. Saliva plays an important role in oral health because of its functions such as oral cavity cleaning, food digestion, chewing, swallowing, speech, and food lubrication. Objective: this study aims to evaluate the salivary flow and the buffering capacity of patients with mental disorders, who use psychotropic agents, treated at the psychiatry services of Professor Edgard Santos University Hospital / Federal University of Bahia. Methodology: the stimulated saliva of 18 patients who participated in this study was collected by chewing a Parafilm® for five minutes. Results: depression was the most common disease. The most commonly used drugs were Risperidone and Clonazepam. Hypo salivation occurred in 44.44% of the patients. There was no change in the buffering capacity of the saliva. Xerostomia was reported in 72.2% of the sample and frequent in 100% of those with hypo salivation. Conclusion: Psychiatric patients deserve special attention. Comparative and longitudinal studies are also necessary in order to detect a causal link.

Traumatic injury risk and agricultural transitions: A view from the American Southeast and beyond.

OBJECTIVES: Bioarchaeological research has documented a general decline in health with the transition from foraging to farming, primarily with respect to changing patterns of morbidity. Less is known about changes in injury risk, an aspect of health more obviously tied to particular landscapes and behaviors associated with different subsistence regimes. The purpose of this research is to evaluate several hypotheses emerging from the ideal free distribution model (Fretwell & Lucas, ) that predict injury risk based on subsistence-specific practices and land use patterns. MATERIALS AND METHODS: Postcranial fracture frequencies for long bones and clavicles in human skeletal remains from three Southeast U.S. regions permit examination of variability in injury risk among low-intensity (floodplain) farmers. Published data on six hunter-gatherer samples, four low-intensity agriculturalist samples, and six high-intensity agriculturalist samples comprise a comparative sample for examining variability in injury risk across three distinct subsistence traditions. Differences are evaluated using Z scores and the Fisher Exact test, Chi-Square test, and Mann-Whitney U test. RESULTS: While statistically significant differences are apparent among low-intensity farming groups in the Southeast sample, in the global comparison postcranial fractures are significantly less common in low-intensity agriculturalists than in hunter-gatherers or high-intensity agriculturalists. DISCUSSION: The results of this study support the hypothesis that, with respect to traumatic injury risk, low-intensity farming is a risk-averse subsistence strategy in comparison with full-time foraging or high-intensity agriculture. These data suggest that it is not agriculture per se that predicts an increase in this health risk, but rather the mode and intensity of agricultural production, findings that have important ramifications for our understanding of the health consequences of major subsistence transitions.

Remote magnetic actuation of micrometric probes for in situ 3D mapping of bacterial biofilm physical properties.

Bacterial adhesion and growth on interfaces lead to the formation of three-dimensional heterogeneous structures so-called biofilms. The cells dwelling in these structures are held together by physical interactions mediated by a network of extracellular polymeric substances. Bacterial biofilms impact many human activities and the understanding of their properties is crucial for a better control of their development - maintenance or eradication - depending on their adverse or beneficial outcome. This paper describes a novel methodology aiming to measure in situ the local physical properties of the biofilm that had been, until now, examined only from a macroscopic and homogeneous material perspective. The experiment described here involves introducing magnetic particles into a growing biofilm to seed local probes that can be remotely actuated without disturbing the structural properties of the biofilm. Dedicated magnetic tweezers were developed to exert a defined force on each particle embedded in the biofilm. The setup is mounted on the stage of a microscope to enable the recording of time-lapse images of the particle-pulling period. The particle trajectories are then extracted from the pulling sequence and the local viscoelastic parameters are derived from each particle displacement curve, thereby providing the 3D-spatial distribution of the parameters. Gaining insights into the biofilm mechanical profile is essential from an engineer's point of view for biofilm control purposes but also from a fundamental perspective to clarify the relationship between the architectural properties and the specific biology of these structures.

In vitro activities of dermaseptins K4S4 and K4K20S4 against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa planktonic growth and biofilm formation.

The rising number of infections caused by biofilm formation and the difficulties associated with their treatment by conventional antimicrobial therapies have led to an intensive search for novel antibiofilm agents. Dermaseptins are antimicrobial peptides with a number of attractive properties that might offer alternative therapies against resistant microorganisms. In this study, we synthesized a set of dermaseptin-derived peptides and evaluated their activities against Gram-positive and Gram-negative bacterial biofilm formation. All dermaseptin-derived peptides demonstrated concentration-dependent antibiofilm activities at microgram concentrations, and their activities were dependent on the nature of the peptides, with the highest levels of activity being exhibited by highly charged molecules. Fluorescent binding and confocal microscopy demonstrated that dermaseptin K4S4, a substituted derivative of the native molecule S4, significantly decreased the viability of planktonic and surface-attached bacteria and stopped biofilm formation under dynamic flow conditions. Cytotoxicity assays with HeLa cells showed that some of the tested peptides were less cytotoxic than current antibiotics. Overall, these findings indicate that dermaseptin derivatives might constitute new lead structures for the development of potent antibiofilm agents.

A new biofilm-associated colicin with increased efficiency against biofilm bacteria.

Formation of bacterial biofilm communities leads to profound physiological modifications and increased physical and metabolic exchanges between bacteria. It was previously shown that bioactive molecules produced within the biofilm environment contribute to bacterial interactions. Here we describe new pore-forming colicin R, specifically produced in biofilms formed by the natural isolate Escherichia coli ROAR029 but that cannot be detected under planktonic culture conditions. We demonstrate that an increased SOS stress response within mature biofilms induces SOS-dependent colicin R expression. We provide evidence that colicin R displays increased activity against E. coli strains that have a reduced lipopolysaccharide length, such as the pathogenic enteroaggregative E. coli LF82 clinical isolate, therefore pointing to lipopolysaccharide size as an important determinant for resistance to colicins. We show that colicin R toxicity toward E. coli LF82 is increased under biofilm conditions compared with planktonic susceptibility and that release of colicin R confers a strong competitive advantage in mixed biofilms by rapidly outcompeting sensitive neighboring bacteria. This work identifies the first biofilm-associated colicin that preferentially targets biofilm bacteria. Furthermore, it indicates that the study of antagonistic molecules produced in biofilm and multispecies contexts could reveal unsuspected, ecologically relevant bacterial interactions influencing population dynamics in natural environments.

Tracking the relevance of the WHO Framework Convention on Tobacco Control in legislation and litigation through the online resource, Tobacco Control Laws.

The WHO Framework Convention on Tobacco Control is increasingly referenced and incorporated into the objectives, definitions and provisions of domestic legislation worldwide. It is also relied upon by courts in interpreting and upholding strong tobacco control measures challenged by the tobacco industry. In this special communication, we describe these trends and explore the important new online resource-Tobacco Control Laws (http://www.tobaccocontrollaws.org)--that has been used to track them.

Sociopolitical effects of bow and arrow technology in prehistoric coastal California.

Bow and arrow technology spread across California between ∼AD 250 and 1200, first appearing in the intermountain deserts of the Great Basin and later spreading to the coast. We critically evaluate the available data for the initial spread in bow and arrow technology and examine its societal effects on the well-studied Northern Channel Islands off the coast of Southern California. The introduction of this technology to these islands between AD 650 and 900 appears to predate the appearance of hereditary inequality between AD 900 and 1300. We conclude, based on the available data, that this technology did not immediately trigger intergroup warfare. We argue that the introduction of the bow and arrow contributed to sociopolitical instabilities that were on the rise within the context of increasing population levels and unstable climatic conditions, which stimulated intergroup conflict and favored the development of hereditary inequality. Population aggregation and economic intensification did occur with the introduction of the bow and arrow. This observation is consistent with the hypothesis that social coercion via intra-group "law enforcement" contributed to changes in societal scale that ultimately resulted in larger groups that were favored in inter-group conflict. We argue that the interplay between intra-group "law enforcement" and inter-group warfare were both essential for the ultimate emergence of social inequality between AD 900 and 1300.

Identification of commensal Escherichia coli genes involved in biofilm resistance to pathogen colonization.

Protection provided by host bacterial microbiota against microbial pathogens is a well known but ill-understood property referred to as the barrier effect, or colonization resistance. Despite recent genome-wide analyses of host microbiota and increasing therapeutic interest, molecular analysis of colonization resistance is hampered by the complexity of direct in vivo experiments. Here we developed an in vitro-to-in vivo approach to identification of genes involved in resistance of commensal bacteria to exogenous pathogens. We analyzed genetic responses induced in commensal Escherichia coli upon entry of a diarrheagenic enteroaggregative E. coli or an unrelated Klebsiella pneumoniae pathogen into a biofilm community. We showed that pathogens trigger specific responses in commensal bacteria and we identified genes involved in limiting colonization of incoming pathogens within commensal biofilm. We tested the in vivo relevance of our findings by comparing the extent of intestinal colonization by enteroaggregative E. coli and K. pneumoniae pathogens in mice pre-colonized with E. coli wild type commensal strain, or mutants corresponding to identified colonization resistance genes. We demonstrated that the absence of yiaF and bssS (yceP) differentially alters pathogen colonization in the mouse gut. This study therefore identifies previously uncharacterized colonization resistance genes and provides new approaches to unravelling molecular aspects of commensal/pathogen competitive interactions.

Mapping of bacterial biofilm local mechanics by magnetic microparticle actuation.

Most bacteria live in the form of adherent communities forming three-dimensional material anchored to artificial or biological surfaces, with profound impact on many human activities. Biofilms are recognized as complex systems but their physical properties have been mainly studied from a macroscopic perspective. To determine biofilm local mechanical properties, reveal their potential heterogeneity, and investigate their relation to molecular traits, we have developed a seemingly new microrheology approach based on magnetic particle infiltration in growing biofilms. Using magnetic tweezers, we achieved what was, to our knowledge, the first three-dimensional mapping of the viscoelastic parameters on biofilms formed by the bacterium Escherichia coli. We demonstrate that its mechanical profile may exhibit elastic compliance values spread over three orders of magnitude in a given biofilm. We also prove that heterogeneity strongly depends on external conditions such as growth shear stress. Using strains genetically engineered to produce well-characterized cell surface adhesins, we show that the mechanical profile of biofilm is exquisitely sensitive to the expression of different surface appendages such as F pilus or curli. These results provide a quantitative view of local mechanical properties within intact biofilms and open up an additional avenue for elucidating the emergence and fate of the different microenvironments within these living materials.

Simple bone cyst: a case report and review of the literature / Cisto ósseo simples: relato de caso e revisão da literatura

Simple bone cysts are pseudocysts affecting long bones and, less frequently, the jaws, especially the mandible. These cysts are generally detected during routine radiography, with the frequent observation of a well-delimited radiolucent area sending projections between the roots of the teeth involved. Simple bone cysts are mainly diagnosed during the second decade of life and have an excellent prognosis, but their etiology is uncertain. The aim of this paper is to report the case of a simple bone cyst in a 15-year-old adolescent seen at the Stomatology Outpatient Clinic, School of Dentistry, Federal University of Bahia. The etiology, clinical course and prognosis of this lesion are discussed based on a systematic review of the literature.

Cistos ósseos simples são pseudocistos que afetam ossos longos e, menos frequentemente, os ossos maxilares, especialmente da mandíbula. Esses cistos geralmente são detectados durante os exames imaginológicos de rotina, com a observação frequente de uma área radiolúcida bem delimitada com projeções entre as raízes dos dentes envolvidos. Cistos ósseos simples são diagnosticados principalmente durante a segunda década de vida e possuem um excelente prognóstico, mas a sua etiologia é incerta. O objetivo deste artigo é relatar o caso de um cisto ósseo simples em um adolescente de 15 anos de idade, visto no Ambulatório de Estomatologia da Faculdade de Odontologia da Universidade Federal da Bahia. A etiologia, curso clínico e prognóstico desta lesão são discutidos com base em uma revisão de literatura sistemática.

Screening of Escherichia coli species biodiversity reveals new biofilm-associated antiadhesion polysaccharides.

UNLABELLED: Bacterial biofilms often form multispecies communities in which complex but ill-understood competition and cooperation interactions occur. In light of the profound physiological modifications associated with this lifestyle, we hypothesized that the biofilm environment might represent an untapped source of natural bioactive molecules interfering with bacterial adhesion or biofilm formation. We produced cell-free solutions extracted from in vitro mature biofilms formed by 122 natural Escherichia coli isolates, and we screened these biofilm extracts for antiadhesion molecules active on a panel of Gram-positive and Gram-negative bacteria. Using this approach, we showed that 20% of the tested biofilm extracts contained molecules that antagonize bacterial growth or adhesion. We characterized a compound, produced by a commensal animal E. coli strain, for which activity is detected only in biofilm extract. Biochemical and genetic analyses showed that this compound corresponds to a new type of released high-molecular-weight polysaccharide whose biofilm-associated production is regulated by the RfaH protein. We demonstrated that the antiadhesion activity of this polysaccharide was restricted to Gram-positive bacteria and that its production reduced susceptibility to invasion and provided rapid exclusion of Staphylococcus aureus from mixed E. coli and S. aureus biofilms. Our results therefore demonstrate that biofilms contain molecules that contribute to the dynamics of mixed bacterial communities and that are not or only poorly detected in unconcentrated planktonic supernatants. Systematic identification of these compounds could lead to strategies that limit pathogen surface colonization and reduce the burden associated with the development of bacterial biofilms on medical devices. IMPORTANCE: We sought to demonstrate that bacterial biofilms are reservoirs for unknown molecules that antagonize bacterial adhesion. The use of natural strains representative of Escherichia coli species biodiversity showed that nonbiocidal antiadhesion polysaccharides are frequently found in mature biofilm extracts (bacterium-free suspensions which contain soluble molecules produced within the biofilm). Release of an antiadhesion polysaccharide confers a competitive advantage upon the producing strain against clinically relevant pathogens such as Staphylococcus aureus. Hence, exploring the biofilm environment provides a better understanding of bacterial interactions within complex communities and could lead to improved control of pathogen colonization.

Health versus fitness: competing themes in the origins and spread of agriculture?

The general picture of human health that has emerged from bioarchaeological studies of the agricultural transition is one of health decline, although the nature and severity of the biological impacts have varied in accordance with worldwide diversity in the timing, duration, and specific characteristics of this economic shift. Conversely and somewhat paradoxically, the emerging picture has also been one of enhanced fertility and population growth. These findings raise challenging questions about the measures bioarchaeologists use to assess the biological costs and benefits of agriculture. It is argued here that these measures fall into two potentially quite distinct categories-physiological fitness (homeostasis) and reproductive (Darwinian) fitness, measures that may assess the costs and benefits of a biocultural system very differently. Both provide valuable insights into questions about our past at levels ranging from the evolution of our species to the unique experiences of individuals and their kin. However, the relative importance of each in larger questions about human adaptation needs to be carefully considered when assessing the biological evidence in questions of causation.

Infectious disease among enslaved African Americans at Eaton's Estate, Warren County, North Carolina, ca. 1830-1850

The skeletal remains of 17 people buried in the Eaton Ferry Cemetery in northern North Carolina provide a means of examining health and infectious disease experience in the XIX century South. The cemetery appears to contain the remains of African Americans enslaved on the Eaton family estate from approximately 1830-1850, and thus offers a window into the biological impacts of North American slavery in the years preceding the Civil War. The sample includes the remains of six infants, one child, and one young and nine mature adults (five men, four women, and one unknown). Skeletal indices used to characterize health and disease in the Eaton Ferry sample include dental caries, antemortem tooth loss, enamel hypoplasia, porotic hyperostosis, periosteal lesions, lytic lesions, and stature. These indicators reveal a cumulative picture of compromised health, including high rates of dental disease, childhood growth disruption, and infectious disease. Specific diseases identified in the sample include tuberculosis and congenital syphilis. Findings support previous research on the health impacts of slavery, which has shown that infants and children were the most negatively impacted segment of the enslaved African American population.

Broad-spectrum biofilm inhibition by a secreted bacterial polysaccharide.

The development of surface-attached biofilm bacterial communities is considered an important source of nosocomial infections. Recently, bacterial interference via signaling molecules and surface active compounds was shown to antagonize biofilm formation, suggesting that nonantibiotic molecules produced during competitive interactions between bacteria could be used for biofilm reduction. Hence, a better understanding of commensal/pathogen interactions within bacterial community could lead to an improved control of exogenous pathogens. To reveal adhesion or growth-related bacterial interference, we investigated interactions between uropathogenic and commensal Escherichia coli in mixed in vitro biofilms. We demonstrate here that the uropathogenic strain CFT073 and all E. coli expressing group II capsules release into their environment a soluble polysaccharide that induces physicochemical surface alterations, which prevent biofilm formation by a wide range of Gram-positive and Gram-negative bacteria. We show that the treatment of abiotic surfaces with group II capsular polysaccharides drastically reduces both initial adhesion and biofilm development by important nosocomial pathogens. These findings identify capsular polymers as antiadhesion bacterial interference molecules, which may prove to be of significance in the design of new strategies to limit biofilm formation on medical in dwelling devices.