Wildfire and Abrupt Ecosystem Disruption on California\u27s Northern Channel Islands at the Allerod-Younger Dryas Boundary (13.0-12.9 ka)

Sedimentary records from California\u27s Northern Channel Islands and the adjacent Santa Barbara Basin (SBB) indicate intense regional biomass burning (wildfire) at the Ållerød–Younger Dryas boundary (~13.0–12.9 ka) (All age ranges in this paper are expressed in thousands of calendar years before present [ka]. Radiocarbon ages will be identified and clearly marked “14C years”.). Multiproxy records in SBB Ocean Drilling Project (ODP) Site 893 indicate that these wildfires coincided with the onset of regional cooling and an abrupt vegetational shift from closed montane forest to more open habitats. Abrupt ecosystem disruption is evident on the Northern Channel Islands at the Ållerød–Younger Dryas boundary with the onset of biomass burning and resulting mass sediment wasting of the landscape. These wildfires coincide with the extinction of Mammuthus exilis [pygmy mammoth]. The earliest evidence for human presence on these islands at 13.1–12.9 ka (~11,000–10,900 14C years) is followed by an apparent 600–800 year gap in the archaeological record, which is followed by indications of a larger-scale colonization after 12.2 ka. Although a number of processes could have contributed to a post 18 ka decline in M. exilis populations (e.g., reduction of habitat due to sea-level rise and human exploitation of limited insular populations), we argue that the ultimate demise of M. exilis was more likely a result of continental scale ecosystem disruption that registered across North America at the onset of the Younger Dryas cooling episode, contemporaneous with the extinction of other megafaunal taxa. Evidence for ecosystem disruption at 13–12.9 ka on these offshore islands is consistent with the Younger Dryas boundary cosmic impact hypothesis [Firestone, R.B., West, A., Kennett, J.P., Becker, L., Bunch, T.E., Revay, Z.S., Schultz, P.H., Belgya, T., Kennett, D.J., Erlandson, J.M., Dickenson, O.J., Goodyear, A.A., Harris, R.S., Howard, G.A., Kloosterman, J.B., Lechler, P., Mayewski, P.A., Montgomery, J., Poreda, R., Darrah, T., Que Hee, S.S., Smith, A.R., Stich, A., Topping, W., Wittke, J.H. Wolbach, W.S., 2007. Evidence for an extraterrestrial impact 12,900 years ago that contributed to the megafaunal extinctions and Younger Dryas cooling. Proceedings of the National Academy of Sciences 104, 16016–16021.]

Water dispersible microbicidal cellulose acetate phthalate film

BACKGROUND: Cellulose acetate phthalate (CAP) has been used for several decades in the pharmaceutical industry for enteric film coating of oral tablets and capsules. Micronized CAP, available commercially as "Aquateric" and containing additional ingredients required for micronization, used for tablet coating from water dispersions, was shown to adsorb and inactivate the human immunodeficiency virus (HIV-1), herpesviruses (HSV) and other sexually transmitted disease (STD) pathogens. Earlier studies indicate that a gel formulation of micronized CAP has a potential as a topical microbicide for prevention of STDs including the acquired immunodeficiency syndrome (AIDS). The objective of endeavors described here was to develop a water dispersible CAP film amenable to inexpensive industrial mass production. METHODS: CAP and hydroxypropyl cellulose (HPC) were dissolved in different organic solvent mixtures, poured into dishes, and the solvents evaporated. Graded quantities of a resulting selected film were mixed for 5 min at 37°C with HIV-1, HSV and other STD pathogens, respectively. Residual infectivity of the treated viruses and bacteria was determined. RESULTS: The prerequisites for producing CAP films which are soft, flexible and dispersible in water, resulting in smooth gels, are combining CAP with HPC (other cellulose derivatives are unsuitable), and casting from organic solvent mixtures containing ≈50 to ≈65% ethanol (EtOH). The films are ≈100 µ thick and have a textured surface with alternating protrusions and depressions revealed by scanning electron microscopy. The films, before complete conversion into a gel, rapidly inactivated HIV-1 and HSV and reduced the infectivity of non-viral STD pathogens >1,000-fold. CONCLUSIONS: Soft pliable CAP-HPC composite films can be generated by casting from organic solvent mixtures containing EtOH. The films rapidly reduce the infectivity of several STD pathogens, including HIV-1. They are converted into gels and thus do not have to be removed following application and use. In addition to their potential as topical microbicides, the films have promise for mucosal delivery of pharmaceuticals other than CAP

A dynamical model reveals gene co-localizations in nucleus

Co-localization of networks of genes in the nucleus is thought to play an important role in determining gene expression patterns. Based upon experimental data, we built a dynamical model to test whether pure diffusion could account for the observed co-localization of genes within a defined subnuclear region. A simple standard Brownian motion model in two and three dimensions shows that preferential co-localization is possible for co-regulated genes without any direct interaction, and suggests the occurrence may be due to a limitation in the number of available transcription factors. Experimental data of chromatin movements demonstrates that fractional rather than standard Brownian motion is more appropriate to model gene mobilizations, and we tested our dynamical model against recent static experimental data, using a sub-diffusion process by which the genes tend to colocalize more easily. Moreover, in order to compare our model with recently obtained experimental data, we studied the association level between genes and factors, and presented data supporting the validation of this dynamic model. As further applications of our model, we applied it to test against more biological observations. We found that increasing transcription factor number, rather than factory number and nucleus size, might be the reason for decreasing gene co-localization. In the scenario of frequency-or amplitude-modulation of transcription factors, our model predicted that frequency-modulation may increase the co-localization between its targeted genes

A bi-directional relationship between obesity and health-related quality of life : evidence from the longitudinal AusDiab study

Objective: To assess the prospective relationship between obesity and health-related quality of life, including a novel assessment of the impact of health-related quality of life on weight gain.Design and setting: Longitudinal, national, population-based Australian Diabetes, Obesity and Lifestyle (AusDiab) study, with surveys conducted in 1999/2000 and 2004/2005.Participants: A total of 5985 men and women aged 25 years at study entry.Main outcome measure(s): At both time points, height, weight and waist circumference were measured and self-report data on health-related quality of life from the SF-36 questionnaire were obtained. Cross-sectional and bi-directional, prospective associations between obesity categories and health-related quality of life were assessed.Results: Higher body mass index (BMI) at baseline was associated with deterioration in health-related quality of life over 5 years for seven of the eight health-related quality of life domains in women (all P0.01, with the exception of mental health, P&gt;0.05), and six out of eight in men (all P&lt;0.05, with the exception of role-emotional, P=0.055, and mental health, P&gt;0.05). Each of the quality-of-life domains related to mental health as well as the mental component summary were inversely associated with BMI change (all P&lt;0.0001 for women and P0.01 for men), with the exception of vitality, which was significant in women only (P=0.008). For the physical domains, change in BMI was inversely associated with baseline general health in women only (P=0.023).Conclusions: Obesity was associated with a deterioration in health-related quality of life (including both physical and mental health domains) in this cohort of Australian adults followed over 5 years. Health-related quality of life was also a predictor of weight gain over 5 years, indicating a bi-directional association between obesity and health-related quality of life. The identification of those with poor health-related quality of life may be important in assessing the risk of future weight gain, and a focus on health-related quality of life may be beneficial in weight management strategies.<br /

Inhibition of sialidase activity and cellular invasion by the bacterial vaginosis pathogen Gardnerella vaginalis

Bacterial vaginosis is a genital tract infection, thought to be caused by transformation of a lactobacillus-rich flora to a dysbiotic microbiota enriched in mixed anaerobes. The most prominent of these is Gardnerella vaginalis (GV), an anaerobic pathogen that produces sialidase enzyme to cleave terminal sialic acid residues from human glycans. Notably, high sialidase activity is associated with preterm birth and low birthweight. We explored the potential of the sialidase inhibitor Zanamavir against GV whole cell sialidase activity using methyl-umbelliferyl neuraminic acid (MU-NANA) cleavage assays, with Zanamavir causing a 30% reduction in whole cell GV sialidase activity (p < 0.05). Furthermore, cellular invasion assays using HeLa cervical epithelial cells, infected with GV, demonstrated that Zanamivir elicited a 50% reduction in cell association and invasion (p < 0.05). Our data thus highlight that pharmacological sialidase inhibitors are able to modify BV-associated sialidase activity and influence host-pathogen interactions and may represent novel therapeutic adjuncts

A bacterial glycan core linked to surface (S)-layer proteins modulates host immunity through Th17 suppression

Tannerella forsythia is a pathogen implicated in periodontitis, an inflammatory disease of the tooth-supporting tissues often leading to tooth loss. This key periodontal pathogen is decorated with a unique glycan core O-glycosidically linked to the bacterium's proteinaceous surface (S)-layer lattice and other glycoproteins. Herein, we show that the terminal motif of this glycan core acts to modulate dendritic cell effector functions to suppress T-helper (Th)17 responses. In contrast to the wild-type bacterial strain, infection with a mutant strain lacking the complete S-layer glycan core induced robust Th17 and reduced periodontal bone loss in mice. Our findings demonstrate that surface glycosylation of this pathogen may act to ensure its persistence in the host likely through suppression of Th17 responses. In addition, our data suggest that the bacterium then induces the Toll-like receptor 2–Th2 inflammatory axis that has previously been shown to cause bone destruction. Our study provides a biological basis for pathogenesis and opens opportunities in exploiting bacterial glycans as therapeutic targets against periodontitis and a range of other infectious diseases

Lakeside Cemeteries in the Sahara: 5000 Years of Holocene Population and Environmental Change

Background: Approximately two hundred human burials were discovered on the edge of a paleolake in Niger that providea uniquely preserved record of human occupation in the Sahara during the Holocene (,8000 B.C.E. to the present). CalledGobero, this suite of closely spaced sites chronicles the rapid pace of biosocial change in the southern Sahara in response tosevere climatic fluctuation.Methodology/Principal Findings: Two main occupational phases are identified that correspond with humid intervals in theearly and mid-Holocene, based on 78 direct AMS radiocarbon dates on human remains, fauna and artifacts, as well as 9 OSLdates on paleodune sand. The older occupants have craniofacial dimensions that demonstrate similarities with mid-Holocene occupants of the southern Sahara and Late Pleistocene to early Holocene inhabitants of the Maghreb. Theirhyperflexed burials compose the earliest cemetery in the Sahara dating to ,7500 B.C.E. These early occupants abandon thearea under arid conditions and, when humid conditions return ,4600 B.C.E., are replaced by a more gracile people withelaborated grave goods including animal bone and ivory ornaments.Conclusions/Significance: The principal significance of Gobero lies in its extraordinary human, faunal, and archaeologicalrecord, from which we conclude the following:(1) The early Holocene occupants at Gobero (7700–6200 B.C.E.) were largely sedentary hunter-fisher-gatherers withlakeside funerary sites that include the earliest recorded cemetery in the Sahara.(2) Principal components analysis of craniometric variables closely allies the early Holocene occupants at Gobero with askeletally robust, trans-Saharan assemblage of Late Pleistocene to mid-Holocene human populations from the Maghreband southern Sahara.(3) Gobero was abandoned during a period of severe aridification possibly as long as one millennium (6200–5200 B.C.E).(4) More gracile humans arrived in the mid-Holocene (5200–2500 B.C.E.) employing a diversified subsistence economybased on clams, fish, and savanna vertebrates as well as some cattle husbandry.(5) Population replacement after a harsh arid hiatus is the most likely explanation for the occupational sequence at Gobero.(6) We are just beginnin

Detection of Borrelia-specific 16S rRNA sequence in total RNA extracted from Ixodes ricinus ticks

A reverse transcriptase - polymerase chain reaction based assay for Borrelia species detection in ticks was developed. The method was based on amplification of 552 nucleotide bases long sequence of 16S rRNA, targeted by Borrelia specific primers. In the present study, total RNA extracted from Ixodes ricinus ticks was used as template. The results showed higher sensitivity for Borrelia detection as compared to standard dark-field microscopy. Method specificity was confirmed by cloning and sequencing of obtained 552 base pairs long amplicons. Phylogenetic analysis of obtained sequences showed that they belong to B. lusitaniae and B. afzelii genospecies. RT-PCR based method presented in this paper could be very useful as a screening test for detecting pathogen presence, especially when in investigations is required extraction of total RNA from ticks