Oligosaccharides produced by partial acetolysis of xanthan gum

Partial acetolysis of the extracellular polysaccharide from Xanthomonas campestris gives the constituent monosaccharides, cellobiose, and three mannose-containing neutral oligosaccharides thought to be derived from the branch points of the polysaccharide. The structural analyses of these oligosaccharides provide further evidence for the presence of β-D-glucopyranosyl and α-D-mannopyranosyl linkages in the polymer.     

Characterization of photodamage to escherichia coli in optical traps

Optical tweezers (infrared laser-based optical traps) have emerged as a powerful tool in molecular and cell biology. However, their usefulness has been limited, particularly in vivo, by the potential for damage to specimens resulting from the trapping laser. Relatively little is known about the origin of this phenomenon. Here we employed a wavelength-tunable optical trap in which the microscope objective transmission was fully characterized throughout the near infrared, in conjunction with a sensitive, rotating bacterial cell assay. Single cells of Escherichia coli were tethered to a glass coverslip by means of a single flagellum: such cells rotate at rates proportional to their transmembrane proton potential (. J. Mol. Biol. 138:541-561). Monitoring the rotation rates of cells subjected to laser illumination permits a rapid and quantitative measure of their metabolic state. Employing this assay, we characterized photodamage throughout the near-infrared region favored for optical trapping (790-1064 nm). The action spectrum for photodamage exhibits minima at 830 and 970 nm, and maxima at 870 and 930 nm. Damage was reduced to background levels under anaerobic conditions, implicating oxygen in the photodamage pathway. The intensity dependence for photodamage was linear, supporting a single-photon process. These findings may help guide the selection of lasers and experimental protocols best suited for optical trapping work.     

Hepatitis C (HCV) therapy for HCV mono-infected and HIV-HCV co-infected individuals living in Nepal

BackgroundDespite direct-acting antivirals (DAA), aims to “eradicate” viral hepatitis by 2030 remain unlikely. In Nepal, an expert consortium was established to treat HCV through Nepal earthquakes aftermath offering a model for HCV treatment expansion in a resource-poor setting.Methodology/Principal findingsIn 2015, we established a network of hepatologists, laboratory experts, and community-based leaders at 6 Opioid Substitution Treatment (OST) sites from 4 cities in Nepal screening 838 patients for a treatment cohort of 600 individuals with HCV infection and past or current drug use. During phase 1, patients were treated with interferon-based regimens (n = 46). During phase 2, 135 patients with optimal predictors (HIV controlled, without cirrhosis, low baseline HCV viral load) were treated with DAA-based regimens. During phase 3, IFN-free DAA treatment was expanded, regardless of HCV disease severity, HIV viremia or drug use. Sustained virologic response (SVR) was assessed at 12 weeks.Median age was 37 years and 95.5% were males. HCV genotype was 3 (53.2%) or 1a (40.7%) and 32% had cirrhosis; 42.5% were HIV-HCV coinfected. The intention-to-treat (ITT) SVR rates in phase 2 and 3 were 97% and 81%, respectively. The overall per-protocol and ITT SVR rates were 97% and 85%, respectively. By multivariable analysis, treatment at the Kathmandu site was protective and substance use, treatment during phase 3 were associated with failure to achieve SVR.Conclusions/SignificanceVery high SVR rates may be achieved in a difficult-to-treat, low-income population whatever the patient’s profile and disease severity. The excellent treatment outcomes observed in this real-life community study should prompt further HCV treatment initiatives in Nepal.     

Signal diversification in Oecanthus tree crickets is shaped by energetic,morphometric, and acoustic trade‐offs

Physiology, physics, and ecological interactions can generate trade‐offs within species, but may also shape divergence among species. We tested whether signal divergence in Oecanthus tree crickets is shaped by acoustic, energetic, and behavioral trade‐offs. We found that species with faster pulse rates, produced by opening and closing wings up to twice as many times per second, did not have higher metabolic costs of calling. The relatively constant energetic cost across species is explained by trade‐offs between the duration and repetition rate of acoustic signals—species with fewer stridulatory teeth closed their wings more frequently such that the number of teeth struck per second of calling and the resulting duty cycle were relatively constant across species. Further trade‐offs were evident in relationships between signals and body size. Calling was relatively inexpensive for small males, permitting them to call for much of the night, but at low amplitude. Large males produced much louder calls, reaching up to four times more area, but the energetic costs increased substantially with increasing size and the time spent calling dropped to only 20% of the night. These trade‐offs indicate that the trait combinations that arise in these species represent a limited subset of conceivable trait combinations.     

Impact of protection on nest take and nesting success of parrots in Africa, Asia and Australasia

Wild parrots represent one of the greatest commercial interests in the legal trade in wild birds. Although it is difficult to quantify, there is a considerable illegal trade in wild parrots. Thirty-six per cent of the world's parrot species are listed by the International Union for the Conservation of Nature as threatened or near threatened, and 55% of these are threatened to some degree by trade. In this paper, we investigate the impact of protection on the number of nests that failed because of nestlings being taken by humans (hereafter nest take) and on nesting success in parrots. We collate data on parrot nest take from published and unpublished studies from Africa, Asia and Australasia, including countries and sites with and without national and local parrot protection measures in place. Nest take was insignificant in Australia, where all studies were from areas with both local and national protection. For less developed countries, levels of nest take were variable between studies, spanning the whole range from 0 to 100%. Protection significantly reduced nest take and correspondingly increased nesting success. Our results corroborate those for the Neotropics; thus, the advantages of protection appear to be independent of geographical location or political and economic conditions. We analysed data on legal trade in wild-caught parrots before and after implementation of the 1992 Wild Bird Conservation Act (which practically eliminated import of parrots to the USA) and found that there was no apparent shift in parrot imports to other global regions from the Neotropics. We suggest that conservation of parrots globally would benefit from similar legislation introduced in other regions, such as the EU (15), which is responsible for more than 60% of global imports of wild parrots.     

Asymmetry of the os pubis: Implications for the Suchey‐Brooks method

Studies of skeletal development frequently document populational incidences of bilateral asymmetry. Degenerative morphological skeletal changes, attributed to age related and irregular ossification, may also progress asymmetrically, either as the result of asymmetric biomechanical factors expressed over the lifespan, asymmetric expression of physiological processes, or progressive magnification of asymmetry acquired previously during development. This study illustrates the effects of bilateral asymmetry on age at death estimates obtained from human skeletal remains. The Suchey‐Brooks method, which uses the pubic symphyseal face for age estimation (Katz and Suchey, Am J Phys Anthropol 69 1986 427–435), was selected for the study based on its widespread use. Asymmetry in the Suchey‐Brooks symphyseal age phases was found in over 60% of a sample composed of 20th century White male individuals from 18 to 86 years of age (N = 130). However, results suggest that the presence of asymmetry does not compromise the accuracy of the Suchey‐Brooks method if the morphologically older symphyseal face of an asymmetric individual is used to estimate age at death. In addition, weak directional asymmetry and a correlation between age and asymmetry were found. This suggests that a comparison of asymmetry in this area with that in other skeletal areas, where the factors originating and influencing asymmetry are better understood, may be useful in better understanding the biological processes which underlie the age markers used in the Suchey‐Brooks method. Am J Phys Anthropol 2009. © 2009 Wiley‐Liss, Inc.     

Inhibition of monocyte oxidative responses by Bordetella pertussis adenylate cyclase toxin

Bordetella pertussis and the other Bordetella species produce a novel adenylate cyclase toxin which enters target cells to catalyze the production of supraphysiologic levels of intracellular cyclic adenosine monophosphate (cAMP). In these studies, dialyzed extracts from B. pertussis containing the adenylate cyclase toxin, a partially purified preparation of adenylate cyclase toxin, and extracts from transposon Tn5 mutants of B. pertussis lacking the adenylate cyclase toxin, were used to assess the effects of adenylate cyclase toxin on human peripheral blood monocyte activities. Luminol-enhanced chemiluminescence of monocytes stimulated with opsonized zymosan was inhibited greater than 96% by exposure to adenylate cyclase toxin-containing extract, but not by extracts from adenylate cyclase toxin-deficient mutants. The chemiluminescence responses to particulate (opsonized zymosan, Leishmania donovani, and Staphylococcus aureus) and soluble (phorbol myristate acetate) stimuli were inhibited equivalently. The superoxide anion generation elicited by opsonized zymosan was inhibited 92% whereas that produced by phorbol myristate acetate was inhibited only 32% by B. pertussis extract. Inhibition of oxidative activity was associated with a greater than 500-fold increase in monocyte cAMP levels, but treated monocytes remained viable as assessed by their ability to exclude trypan blue and continued to ingest particulate stimuli. The major role of the adenylate cyclase toxin in the inhibition of monocyte oxidative responses was demonstrated by: 1) little or no inhibition by extracts from B. pertussis mutants lacking adenylate cyclase toxin; 2) high level inhibition with extract from B. parapertussis, a related species lacking pertussis toxin; and 3) a reciprocal relationship between monocyte cAMP levels and inhibition of opsonized zymosan-induced chemiluminescence using both crude extract and partially purified adenylate cyclase toxin. Pertussis toxin, which has been shown to inhibit phagocyte responses to some stimuli by a cAMP-independent mechanism, had only a small (less than 20%) inhibitory effect when added at concentrations up to 100-fold in excess of those present in B. pertussis extract. These data provide strong support for the hypothesis that B. pertussis adenylate cyclase toxin can increase cAMP levels in monocytes without compromising target cell viability or impairing ingestion of particles and that the resultant accumulated cAMP is responsible for the inhibition of oxidative responses to a variety of stimuli.     

The use of immunologically competent cells from pig mesenteric lymph nodes to treat pulmonary tumors in mice

Summary Pulmonary tumors were produced in A strain mice by intravenous injection of 1×10⁶ A strain mammary carcinoma cells. The mice were killed on day 14, their lungs fixed in Bouin's fluid, and the number of tumors counted.The mesenteric lymph node chains of pigs were immunized by implantation of tissue into the mesentery. In all animals the middle segment of node chain was excised. The remaining segments of node proximal and distal to the resected segment were, in separate pigs, nonimmunized or immunized against mouse tumor, immunized against mouse tumor or mouse skin, or immunized against human tumor or mouse tumor. All segments of node chain were removed 7 days after immunization for preparation of cell suspensions.When tumor cells were combined in a ratio of 1 : 10 or 1 : 60 with mouse tumor-immune pig cells, there was a significant reduction in tumor formation compared to that in mice receiving tumor cells alone.Injection of mouse tumor-immune pig cells on day 7, to treat tumors inoculated on day 0, was ineffective. However, when the mice received, in addition, 200 rad thoracic irradiation on day 3, immune pig cells reduced the number of tumors compared to that in animals receiving irradiation alone, or irradiation and nonimmune pig cells.In further experiments, in order to increase the number of pig cells reaching the lungs, a splenectomy was performed on day 6, prior to intravenous injection of immune cells on day 7. A comparison was made of the antitumor effect of pig cells immunized against mouse tumor, mouse skin, or human tumor. Cells immunized against either mouse tissue were equally effective in reducing the number of tumors compared to the number in animals receiving tumor cells alone. However, cells immune to human tumor were ineffective.     

Coordinate Regulation of Choline Acetyltransferase, Tyrosine Hydroxylase, and Neuropeptide mRNAs by Ciliary Neurotrophic Factor and Leukemia Inhibitory Factor in Cultured Sympathetic Neurons

Abstract: The neurotransmitter phenotype switch that occurs in cultures of rat superior cervical ganglion neurons after treatment with leukemia inhibitory factor or ciliary neurotrophic factor is a useful model permitting investigation of the mechanisms of cytokine-mediated differentiation. Recently the actions of leukemia inhibitory factor and ciliary neurotrophic factor have been linked through their interactions with related receptor complexes. Here we compare the effects of these two cytokines on gene expression in sympathetic neuronal cultures and begin to investigate their mechanisms. We report that, as has been shown for leukemia inhibitory factor, ciliary neurotrophic factor regulates peptides and classical transmitters in these cultures at the mRNA level. In addition, we find that the induction of substance P mRNA by these cytokines is rapid, dependent on protein synthesis, and occurs in 40–50% of superior cervical ganglion neurons in dissociated culture.