Identification of mosquito repellent odours from Ocimum forskolei

<p>Abstract</p> <p>Background</p> <p>Native mosquito repellent plants have a good potential for integrated mosquito control in local settings. <it>Ocimum forskolei</it>, Lamiaceae, is used in Eritrea as a spatial mosquito repellent inside houses, either through crushing fresh plants or burning dry plants. We verified whether active repellent compounds could be identified using gas-chromatography coupled electroantennogram recordings (GC-EAD) with headspace extracts of crushed plants.</p> <p>Results</p> <p>EAD active compounds included (R)-(-)-linalool, (S)-(+)-1-octen-3-ol, trans-caryophyllene, naphthalene, methyl salicylate, (R)-(-)-α-copaene, methyl cinnamate and (E)-ocimene. Of these compounds (R)-(-)-linalool, methyl cinnamate and methyl salicylate reduced landing of female <it>Aedes aegypti </it>on human skin-odor baited tubes. The latter two are novel mosquito repellent compounds.</p> <p>Conclusions</p> <p>The identification of mosquito repellent compounds contributes to deciphering the mechanisms underlying repulsion, supporting the rational design of novel repellents. The three mosquito repellent compounds identified in this study are structurally dissimilar, which may indicate involvement of different sensory neurons in repulsion. Repulsion may well be enhanced through combining different repellent plants (or their synthetic mimics), and can be a locally sustainable part in mosquito control efforts.</p

Acetyl-11-keto-β-boswellic acid (AKBA); targeting oral cavity pathogens

<p>Abstract</p> <p>Background</p> <p>Boswellic acids mixture of triterpenic acids obtained from the oleo gum resin of <it>Boswellia serrata </it>and known for its effectiveness in the treatment of chronic inflammatory disease including peritumor edema. Boswellic acids have been extensively studied for a number of activities including anti inflammatory, antitumor, immunomodulatory, and inflammatory bowel diseases. The present study describes the antimicrobial activities of boswellic acid molecules against oral cavity pathogens. Acetyl-11-keto-β-boswellic acid (AKBA), which exhibited the most potent antibacterial activity, was further evaluated in time kill studies, mutation prevention frequency, postantibiotic effect (PAE) and biofilm susceptibility assay against oral cavity pathogens.</p> <p>Findings</p> <p>AKBA exhibited an inhibitory effect on all the oral cavity pathogens tested (MIC of 2-4 μg/ml). It exhibited concentration dependent killing of S<it>treptococcus mutans </it>ATCC 25175 up to 8 × MIC and also prevented the emergence of mutants of <it>S.mutans </it>ATCC 25175 at 8× MIC. AKBA demonstrated postantibiotic effect (PAE) of 5.7 ± 0.1 h at 2 × MIC. Furthermore, AKBA inhibited the formation of biofilms generated by <it>S.mutans </it>and <it>Actinomyces viscosus </it>and also reduced the preformed biofilms by these bacteria.</p> <p>Conclusions</p> <p>AKBA can be useful compound for the development of antibacterial agent against oral pathogens and it has great potential for use in mouthwash for preventing and treating oral infections.</p

Canine trypanosomosis: Clinical observations and morphological pathology associated with natural infection of Trypanosoma congolense in exotic breeds of dog in Abeokuta, Nigeria

Clinical and pathological aspects of canine trypanosomosis were determined in naturally infected dogs presented to the Veterinary Teaching Hospital, Federal University of Agriculture, Abeokuta, at different times between 2012 and 2013. The breeds, sexes, ages and body weights of the dogs were recorded.  Clinical signs were observed. Blood samples were collected to determine their packed cell volumes  (PCVs) and parasitaemia. Post-mortem examinations were carried out on 6 dogs that died of the disease and tissue samples were collected and fixed in 10% buffered formalin for histopathology. Trypanosoma species was characterized using polymerase chain reaction. Trypansoma species detected by microscopy was confirmed as T. congolense savannah sub-type by PCR. Clinically, the dogs were anorexic, lethargic and showed lymphadenopathy. Their body temperatures ranged from 40-41.6oC,  Respiratory rates were 28-34/minute, 4 out of 6 cases examined at post-mortem showed epistaxis. The gross lesions were pale mucous membranes, severe pulmonary congestions, haemorrhages and oedema (4/6), marked hydrothorax measuring 1-2 litres (5/6), misshapen heart with petechial and ecchymotic haemorrhages in the epicardium (4/6), severely enlarged and icteric livers and splenomegaly. The intestinal mucous membranes were haemorrhagic (2/6), the kidneys were pale and the testes were haemorrhagic (2/6). Microscopic lesions were severe pulmonary congestion, haemorrhages, oedema and infiltration by inflammatory cells, severe haemorrhagic myocarditis, hyperplastic lymphodenopathy, varying degree of degeneration and necrosis with inflammatory reactions in the lungs, hearts, livers,  spleens and kidneys. The liver sinusoids were dilated and the hepatocytes show varying degree of fatty change. In some cases, hepatocytes were atrophic. In all the six cases, Trypanosome species were characterized as T. congolense savannah type. The pathogenicity of trypanosomes in dogs was discussed.Keywords: trypanosomosis, clinical signs, parasitaemia, pathology, dogs. rhodesense