Neutrophils Contribute to the Protection Conferred by ArtinM against Intracellular Pathogens: A Study on Leishmania major

ArtinM, a D-mannose binding lectin from Artocarpus heterophyllus, has immunomodulatory activities through its interaction with N-glycans of immune cells, culminating with the establishment of T helper type 1 (Th1) immunity. This interaction protects mice against intracellular pathogens, including Leishmania major and Leishmania amazonensis. ArtinM induces neutrophils activation, which is known to account for both resistance to pathogens and host tissue injury. Although exacerbated inflammation was not observed in ArtinM-treated animals, assessment of neutrophil responses to ArtinM is required to envisage its possible application to design a novel immunomodulatory agent based on carbohydrate recognition. Herein, we focus on the mechanisms through which neutrophils contribute to ArtinM-induced protection against Leishmania, without exacerbating inflammation. For this purpose, human neutrophils treated with ArtinM and infected with Leishmania major were analyzed together with untreated and uninfected controls, based on their ability to eliminate the parasite, release cytokines, degranulate, produce reactive oxygen species (ROS), form neutrophil extracellular traps (NETs) and change life span. We demonstrate that ArtinM-stimulated neutrophils enhanced L. major clearance and at least duplicated tumor necrosis factor (TNF) and interleukin-1beta (IL-1β) release; otherwise, transforming growth factor-beta (TGF-β) production was reduced by half. Furthermore, ROS production and cell degranulation were augmented. The life span of ArtinM-stimulated neutrophils decreased and they did not form NETs when infected with L. major. We postulate that the enhanced leishmanicidal ability of ArtinM-stimulated neutrophils is due to augmented release of inflammatory cytokines, ROS production, and cell degranulation, whereas host tissue integrity is favored by their shortened life span and the absence of NET formation. Our results reinforce the idea that ArtinM may be considered an appropriate molecular template for the construction of an efficient anti-infective agent.     

Ueber einige von J. Menyhardt in Südafrika gesammelte Süsswasseralgen

Ohne Zusammenfassung     

Isolation ofBacillus schlegelii,a thermophilic,hydrogen oxidizing,aerobic autotroph,from geothermal and nongeothermal environments

Thermophilic hydrogen-oxidizing strains forming round, terminal endospores were isolated from geothermal areas. They were neutrophilic and facultatively autotrophic. They resembledBacillus schlegelii, a thermophilic hydrogen bacterium found so far only in cold environments. Phenotypic similarities, as well as DNA G+C content and DNA:DNA homologies, clearly revealed that the isolated strains belonged to the taxospeciesB. schlegelii. Hence, the strains ofB. schlegelii found in cold environments are probably allochthonous, their origin being geothermal and volcanic areas.     

The cytomorphology of goblet cells of the fetal intestine. Studies of the large intestine of cattle (Bos primigenius taurus)

In the region of the base of the intestinal crypts undifferentiated goblet cells display a configuration and constellation of organelles and membrane structures that are indicative of their importance for function. These images at this stage of development deliver a scenario of the mechanism of secretory granule production: aggregates of protein vesicles from the "transitional elements" (PALADE) of the granular endoplasmic reticulum are, so to speak, rolled up on the trans side of the Golgi apparatus by inversion of peripheral membrane segments of the innermost Golgi lamellae, thereby forming corpuscles. The origin of the capsulated vacuoles, which contain vesicles as single elements or as conglomerates, is well established. Their capsule consists of a trilaminar external and external and internal membrane; between them lies condensed material of the Golgi apparatus. In the opinion of the present author, the development of the ensheathed vacuoles represents a basic, more general mechanism. In contrast, the further steps of synthesis, for the formation of secretory granules, are more heterogeneous. Condensation of the vesicles and the inner capsular membrane results in the formation of a prosecretory granule, which in the basic element in the process of secretory granule production. The prosecretory granules develop singly or by fusion with other granules to give primary secretory granules. The complexity of this mechanism of secretory granule formation, however, becomes evident when considering the apposition of capsulated vacuoles and prosecretory--primary--secondary secretory granules, of prosecretory and primary secretory granules as well as prosecretory granules and secondary secretory granules. Generally, primary granules show a tendency to become secondary secretory granules or to fuse with them. During maturation of the goblet cells the secretory granules fuse to form larger mucous bodies in the theca by fusion of the laminae of the membranes; a final product, there is a homogeneous mucous mass devoid of membranes.     

Replicate plating: does it increase reliability?

K.K. WILLE, B.R. VOWELS, A.N. FOGLIA, C.A. BERGE, B.M. SCHNELL AND F.W. BRIESE. 1996. As a part of a clinical study to evaluate the antibacterial effect of a topically applied erythromycin gel, microbiological specimens were taken from two groups of patients : one group using 2% erythromycin gel and the other group using a placebo gel. These specimens were plated in triplicate using a common source on bacteriological media using standard procedures. After the appropriate incubation times, the numbers of aerobic and anaerobic organisms were counted separately from each of three plates. A comparison of the bacterial colony counts from the replicate plates showed a high degree of similarity for each type of organism. Tests for treatment differences in organism counts were performed based on single, double and triplicate plating. The results obtained were almost identical, suggesting that replicate plating from a common source is no more accurate than single plating. The only apparent advantage of this type of replicate plating is heightened confidence in the reliability of bacterial counts from single plates.     

Tum—mutation P35B generates the MHC-binding site of a new antigenic peptide

Immunogenic tumor cell variant P35 was obtained by mutagen treatment of mouse mastocytoma P815. It express a potent new antigen recognized by syngeneic cytolytic T lymphocytes (CTL). This antigen is the result of a point mutation in a gene that is expressed by most healthy cells. A decapeptide encoded by the region spanning the mutation sensitized P815 cells to the relevant CTL, whereas the homologous decapeptide corresponding to the normal sequence did not. Only the mutant decapeptide was capable of enhancing the expression of the D^d-presenting molecule at the cell surface, indicating that the mutation generates a motif which enables the antigenic peptide to bind to D^d. Correspondence to: T. Boon.     

A rapid method for the determination of bacterial fatty acid composition

Heat treatment of spores of non-proteolytic strains of Clostridium botulinum at 75–90°C, and enumeration of survivors on a nutrient medium containing lysozyme gave biphasic survival curves. A majority of spores were inactivated rapidly by heating, and the apparent heat-resistance of these spores was similar to that observed by enumeration on medium without lysozyme. A minority of spores showed much greater heat-resistance, due to the fact that the spore coat was permeable to lysozyme, which diffused into the spore from the medium and replaced the heat-inactivated germination system. The proportion of heated spores permeable to lysozyme was between 0.2 and 1.4% for spores of strains 17B (type B) and Beluga (type E), but was about 20% for spores of strain Foster B96 (type E). After treatment of heated spores with alkaline thioglycolate, all were permeable to lysozyme. D-values for heated spores that were permeable to lysozyme (naturally and after treatment with thioglycolate) were: for strain 17B, D₈₅°C, 100 min; D₉₀°C, 18.7 min; D₉₅°C, 4.4 min; for strain Beluga, D₈₅°C, 46 min; D₉₀°C, 11.8 min; D₉₅°C, 2.8 min. The z-values for these spores of strains 17B and Beluga were 7.6°C and 8.3°C.