Chemodiversity of propolis samples collected in various areas of Benin and Congo: Chromatographic profiling and chemical characterization guided by 13 C NMR dereplication.

INTRODUCTION: Propolis is a resinous natural substance collected by honeybees from buds and exudates of various trees and plants; it is widely accepted that the composition of propolis depends on the phytogeographic characteristics of the site of collection. OBJECTIVES: The aim of this study was to determine the phytochemical composition of ethanolic extracts from eight propolis batches collected in different regions of Benin (north, center, and south) and Congo, Africa. MATERIAL AND METHODS: Characterization of propolis samples was performed by using different hyphenated chromatographic methods combined with carbon-13 nuclear magnetic resonance (13 C NMR) dereplication with MixONat software. Their antioxidant or anti-advanced glycation end-product (anti-AGE) activity was then evaluated by using diphenylpicrylhydrazyl and bovine serum albumin assays, respectively. RESULTS: Chromatographic analyses combined with 13 C NMR dereplication showed that two samples from the center of Benin exhibited, in addition to a huge amount of pentacyclic triterpenes, methoxylated stilbenoids or phenanthrenoids, responsible for the antioxidant activity of the extract for the first one. Among them, combretastatins might be cytotoxic. For the second one, the prenylated flavanones known in Macaranga-type propolis were responsible for its significant anti-AGE activity. The sample from Congo was composed of many triterpene derivatives belonging to Mangifera indica species. CONCLUSION: Therefore, propolis from the center of Benin seems to be of particular interest, due to its antioxidant and anti-AGE properties. Nevertheless, as standardization of propolis is difficult in tropical zones due to its great chemodiversity, a systematic phytochemical analysis is required before promoting the use of propolis in food and health products in Africa.

Bacterial Infections in Humans and Nonhuman Primates from Africa: Expanding the Knowledge.

The close phylogenetic relationship between humans and other primates creates exceptionally high potential for pathogen exchange. The surveillance of pathogens in primates plays an important role in anticipating possible outbreaks. In this study, we conducted a molecular investigation of pathogenic bacteria in feces from African nonhuman primates (NHPs). We also investigated the pathogens shared by the human population and gorillas living in the same territory in the Republic of Congo. In total, 93% of NHPs (n=176) and 95% (n=38) of humans were found to carry at least one bacterium. Non-pallidum Treponema spp. (including T. succinifaciens, T. berlinense, and several potential new species) were recovered from stools of 70% of great apes, 88% of monkeys, and 79% of humans. Non-tuberculosis Mycobacterium spp. were also common in almost all NHP species as well as in humans. In addition, Acinetobacter spp., members of the primate gut microbiota, were mainly prevalent in human and gorilla. Pathogenic Leptospira spp. were highly present in humans (82%) and gorillas (66%) stool samples in Congo, but were absent in the other NHPs, therefore suggesting a possible gorillas-humans exchange. Particular attention will be necessary for enteropathogenic bacteria detected in humans such as Helicobacter pylori, Salmonella spp. (including S. typhi/paratyphi), Staphyloccocus aureus, and Tropheryma whipplei, some of which were also present in gorillas in the same territory (S. aureus and T. whipplei). This study enhances our knowledge of pathogenic bacteria that threaten African NHPs and humans by using a non-invasive sampling technique. Contact between humans and NHPs results in an exchange of pathogens. Ongoing surveillance, prevention, and treatment strategies alone will limit the spread of these infectious agents.

Enteroviruses from Humans and Great Apes in the Republic of Congo: Recombination within Enterovirus C Serotypes.

Enteroviruses (EVs) are viruses of the family Picornaviridae that cause mild to severe infections in humans and in several animal species, including non-human primates (NHPs). We conducted a survey and characterization of enteroviruses circulating between humans and great apes in the Congo. Fecal samples (N = 24) of gorillas and chimpanzees living close to or distant from humans in three Congolese parks were collected, as well as from healthy humans (N = 38) living around and within these parks. Enteroviruses were detected in 29.4% of gorilla and 13.15% of human feces, including wild and human-habituated gorillas, local humans and eco-guards. Two identical strains were isolated from two humans coming from two remote regions. Their genomes were similar and all genes showed their close similarity to coxsackieviruses, except for the 3C, 3D and 5'-UTR regions, where they were most similar to poliovirus 1 and 2, suggesting recombination. Recombination events were found between these strains, poliovirus 1 and 2 and EV-C99. It is possible that the same EV-C species circulated in both humans and apes in different regions in the Congo, which must be confirmed in other investigations. In addition, other studies are needed to further investigate the circulation and genetic diversity of enteroviruses in the great ape population, to draw a definitive conclusion on the different species and types of enteroviruses circulating in the Republic of Congo.

Antimicrobial treatment reduces intestinal microflora and improves protein digestive capacity without changes in villous structure in weanling pigs.

The immediate post-weaning period is often associated with gut malfunction and diarrhoea for young pigs. Administration of antimicrobials remains an effective way to control weaning diarrhoea but it remains unclear how they affect gut physiology and microbiology although this is a prerequisite for being able to devise better alternatives. Hence, for 7 d we treated pigs, weaned at 24 d of age, with a combination of amoxicillin (25 mg/kg feed and injection of 8.75 mg/kg body weight per 12 h) and ZnO (2.5 g/kg feed). The pigs treated with antimicrobials (n 11) showed no signs of gut malfunction at any time, whereas untreated weaned controls (n 11) developed clinical diarrhoea. The antimicrobial treatment resulted in a higher daily weight gain compared with weaned controls (101 v. -44 g/d, P < 0.0001), whereas both groups had a similar degree of villous atrophy compared with unweaned 24-d-old controls (n 8; P < 0.05). The antimicrobial treatment gave a dramatic reduction in small intestinal microbial diversity, and specifically prevented tissue colonization with Escherichia coli compared with weaned controls. Further, the antimicrobial treatment improved amylase, trypsin and small intestinal aminopeptidase A and N activities (all P < 0.05). Specifically for the colon, the antimicrobial treatment was associated with reduced tissue weight ( -23 %, P < 0.05), reduced concentration of SCFA (P < 0.05), and increased mucosal goblet cell area (P < 0.0001) compared with weaned controls. We conclude that the beneficial effects of antimicrobials are mediated not only through reduction in intestinal bacterial load, but also through a stimulation of protein digestive function and goblet cell density.

Double radial immunodiffusion as a tool to identify pregnancy-associated glycoproteins in ruminant and nonruminant placentae.

Pregnancy-associated glycoproteins (PAGs) are antigens synthesized in the superficial layers of the ruminant trophoblast. Initially, they were identified either as proteins released into the maternal bloodstream (where they have applications in pregnancy diagnosis) (PAG1) or as molecules binding to the LH receptor (PAG2). In this study, double radial immunodiffusion was used to test the ability of antisera raised against different PAG molecules (bovine, ovine and caprine) to react with placental extracts from nonruminants (rabbit, cat, mouse, pig, and wild pig) and ruminants (cow, ewe, and goat). Placental extracts from all nonruminants tested except rabbit reacted with anti bovine PAG2 (anti-boPAG2). Extracts of ruminant placentas reacted with different antisera, confirming the expression of various PAG molecules. According to the time at which the placentas were collected (early or middle pregnancy), the reaction differed as regards the thickness, position, and number of precipitation lines, suggesting that PAG expression varies as pregnancy progresses. Bos indicus and Bos taurus placental extracts exhibited different reactions with anti-boPAG2: a single precipitation line in the former case and two lines in the latter. This suggests differential expression of boPAG2 related glycoproteins in these two subspecies.

Development and validation of a specific radioimmunoassay for equine osteocalcin.

This study describes for the first time the development and validation of a sensitive and specific radioimmunoassay (RIA) for equine osteocalcin (OC) quantification using purified equine OC as standard, tracer, and immunogen for antibody formation in rabbits. The assay allowed to measure equine serum OC levels with a sensitivity of 0.2 ng/mL. Immunoreactive serum OC values of clinically normal, different-aged horses ranged from 3.68 to 127.31 ng/mL. Intra- and inter-assay coefficients of variation (CV) were 6.2 and 8.2%, respectively. Serial equine serum sample dilutions were linear. The recovery of equine OC from equine serum samples ranged from 93.88 to 107.9%. There was a tight correlation between OC values measured with the equine-specific OC RIA and two commercially available bovine-specific OC RIA kits. However, highest serum OC values were obtained with the equine-specific OC RIA. In conclusion, our equine-specific OC RIA is sensitive, linear, accurate, precise, and reproducible. The assay allowed to quantify OC in equine serum samples and might, therefore, be used to monitor equine osteoblast activity associated with bone diseases, exercise, therapy forms or diet.

Characterization of pregnancy-associated glycoproteins extracted from zebu (Bos indicus) placentas removed at different gestational periods.

In the present work, two biochemical approaches were used to characterize PAGs isolated from Bos indicus fetal cotyledons removed at different gestational ages. The first procedure included acidic and ammonium sulfate precipitations, anion and cation exchange chromatographies and the second included pepstatin-agarose affinity chromatography. A bovine PAG radioimmunoassay was used to monitor the immunoreactivity throughout the isolation procedures. The most immunoreactive fractions issued from cation exchange and affinity chromatographies were analyzed by SDS-PAGE and Western blotting, before transfer to a polyvinylidene difluoride (PVDF) membrane for NH2-microsequence determination. Use SDS-PAGE and Western blotting, different isoforms of PAG with apparent molecular masses of 51 to 69 kDa and isoelectric points varying from 4.4 to 6.7 were identified in the placentas from different gestational ages. N-terminal microsequencing (10 to 25 aa long) indicates the expression of one single terminal amino acid sequence in the Bos indicus placenta, which is 100% identical to the bovine PAG-1.