Stromal IFN-γR-Signaling Modulates Goblet Cell Function During Salmonella Typhimurium Infection

Enteropathogenic bacteria are a frequent cause of diarrhea worldwide. The mucosal defenses against infection are not completely understood. We have used the streptomycin mouse model for Salmonella Typhimurium diarrhea to analyze the role of interferon gamma receptor (IFN-γR)-signaling in mucosal defense. IFN-γ is known to contribute to acute S. Typhimurium diarrhea. We have compared the acute mucosal inflammation in IFN-γR-/- mice and wild type animals. IFN-γR-/- mice harbored increased pathogen loads in the mucosal epithelium and the lamina propria. Surprisingly, the epithelium of the IFN-γR-/- mice did not show the dramatic “loss” of mucus-filled goblet cell vacuoles, a hallmark of the wild type mucosal infection. Using bone marrow chimeric mice we established that IFN-γR-signaling in stromal cells (e.g. goblet cells, enterocytes) controlled mucus excretion/vacuole loss by goblet cells. In contrast, IFN-γR-signaling in bone marrow-derived cells (e.g. macrophages, DCs, PMNs) was required for restricting pathogen growth in the gut tissue. Thus IFN-γR-signaling influences different mucosal responses to infection, including not only pathogen restriction in the lamina propria, but, as shown here, also goblet cell function

Do bednets including piperonyl butoxide offer additional protection against populations of Anopheles gambiae s.l. that are highly resistant to pyrethroids? An experimental hut evaluation in Burkina Fasov

Malaria control is dependent on the use of Long Lasting Insecticidal Nets (LLINs) containing pyrethroids. A new generation of LLINs containing both pyrethroids and the synergist piperonyl butoxide (PBO LLINs) have been developed in response to increasing pyrethroid resistance in African malaria vectors but questions remain about the performance of these nets in areas where pyrethroid resistance is at very high levels. This study was conducted in two settings in Southwest Burkina Faso, Vallée du Kou 5 and Tengrela where Anopheles gambiae s.l. mortality rates in WHO discriminating dose assays were < 14 % for permethrin < 33 % for deltamethrin (< 33 %). When mosquitoes were pre-exposed to PBO in WHO tube assays mortality rates increased substantially but full susceptibility was not restored. Molecular characterisation revealed high levels of kdr alleles and elevated levels of P450s previously implicated in pyrethroid resistance. In cone bioassays and experimental huts the PBO LLINs outperformed the pyrethroid only equivalents from the same manufacturers. Blood feeding rates were 1.6 - 2.2 fold lower, and mortality rates were increased by 1.69 – 1.78 -fold in huts with PBO LLINs versus non PBO LLINs. This study indicates that PBO LLINs provide greater personal and community level protection than standard LLINs against highly pyrethroid resistant mosquito populations

Surveys on Propithecus verreauxi deckeni, a melanistic variant, and P. v. coronatus in north-west Madagascar

Propithecus verreauxi is currently divided into three or four subspecies. Decken's sifaka, P. v. deckeni, and the crowned sifaka, P. v. coronatus, are believed to be synonymous by some authors, while others regard them as separate subspecies. The results of a survey on an isolated melanistic population of Decken's sifaka, known from museum specimens collected in Ambararatabe, as well as the results of additional surveys carried out within the ranges of P. v. deckeni and P. v. coronatus are presented. A detailed description and photographs of the melanistic variant are provided. The data are employed to argue the case for recognition of the subspecific status of the endangered P. v. coronatus. The consistency of sightings of P. v. coronatus to the east of the river Mahavavy and to the west of the river Betsiboka, and sightings of P. v. deckeni to the west of the Mahavavy indicate clear separation of the two subspecies in the lower reaches of two rivers. Clarification of the status of the enigmatic museum specimens from Ambararatabe, representing a melanisticform rather than hybridization of P. v. deckeni and P. v. coronatus, lends further support to this argumen