Susceptibility of mycotoxigenic fungi to commercial fungicides, a potential tool for mycotoxin control in maize in Kenya

Mycotoxin contamination of food grains represents significant health and economic challenges in developing countries as well as the developed world. Mycotoxin- producing fungal species affecting maize mainly belong to the genera Aspergillus, Fusarium, and Penicillium.They pose serious phytopathological and mycotoxicological risks both at pre-harvest and post-harvest stages. Maize in Kenya has been associated with frequent outbreaks of aflatoxin contamination. A number of mycotoxin control strategies both chemical and biological have been developed as potential tools for mycotoxin control. A Laboratory based cross-sectional study was carried out in a Mycology Laboratory at the Center for Microbiology Research in Kenya Medical Research Institute, Nairobi, Kenya. A total of 138 maize samples obtained from Machakos, Nairobi, Mombasa, Kitale and Kisumu were subjected to mycological analysis. The samples were treated with the fungicides; Antracol (propineb), Milraz (propineb700g/kg and Cymoxanil60g/kg), Mistress (Cymoxanil 8% and Mancozeb 64%) and Victory (Metalaxy 80g/kg and Mancozeb 640g/kg.) before inoculation on Sabourauds dextrose agar (SDA). Infestation rates on fungicide- treated and non treated control maize kernels were scored. The susceptibility of the isolates to the four test fungicides was determined by disk diffusion technique. All the maize samples were infested by moulds and there was a significant difference in regional infestation rates (p<0.05). Maize from Mombasa had the lowest infestation of 72.5% while Nairobi was the highest with 99.1%. Fungi of the genera Aspergillus, Fusarium, and Penicillium were frequently isolated from the five regions. There was a significant reduction {p<0.05 (0.00)} of infestation rates on fungicide- treated maize compared to the untreated. Generally, 26% (n=35) and 34% (n=47) of maize samples treated with Mistress and Victory, respectively had 0% infestation while those treated with Milraz and Antracol were 10% (n=14) and 14% (n=19), respectively. Some mycotoxigenic isolates were found to be resistant to more than one of the test fungicides. However, their in- vitro antifungal activity is of great importance and could further be evaluated to determine their field efficacy for mycotoxin control in maize.Key words: Maize, Mycotoxigenic fungi, Fungicides, Susceptibility

A cross-sectional analysis of factors associated with detection of oncogenic human papillomavirus in human immunodeficiency virus-infected and uninfected Kenyan women

BACKGROUND: Cervical cancer is caused by oncogenic human papillomaviruses (HPV) and is one of the most common malignancies in women living in sub-Saharan Africa. Women infected with the human immunodeficiency virus (HIV) have a higher incidence of cervical cancer, but the full impact on HPV detection is not well understood, and associations of biological and behavioral factors with oncogenic HPV detection have not been fully examined. Therefore, a study was initiated to investigate factors that are associated with oncogenic HPV detection in Kenyan women. METHODS: Women without cervical dysplasia were enrolled in a longitudinal study. Data from enrollment are presented as a cross-sectional analysis. Demographic and behavioral data was collected, and HPV typing was performed on cervical swabs. HIV-uninfected women (n = 105) and HIV-infected women (n = 115) were compared for demographic and behavioral characteristics using t-tests, Chi-square tests, Wilcoxon sum rank tests or Fisher\u27s exact tests, and for HPV detection using logistic regression or negative binomial models adjusted for demographic and behavioral characteristics using SAS 9.4 software. RESULTS: Compared to HIV-uninfected women, HIV-infected women were older, had more lifetime sexual partners, were less likely to be married, were more likely to regularly use condoms, and were more likely to have detection of HPV 16, other oncogenic HPV types, and multiple oncogenic types. In addition to HIV, more lifetime sexual partners was associated with a higher number of oncogenic HPV types (aIRR 1.007, 95% CI 1.007-1.012). Greater travel distance to the clinic was associated with increased HPV detection (aOR for detection of \u3e /= 2 HPV types: 3.212, 95% CI 1.206-8.552). Older age (aOR for HPV 16 detection: 0.871, 95% CI 0.764-0.993) and more lifetime pregnancies (aOR for detection of oncogenic HPV types: 0.706, 95% CI, 0.565-0.883) were associated with reduced detection. CONCLUSION: HIV infection, more lifetime sexual partners, and greater distance to health-care were associated with a higher risk of oncogenic HPV detection, in spite of ART use in those who were HIV-infected. Counseling of women about sexual practices, improved access to health-care facilities, and vaccination against HPV are all potentially important in reducing oncogenic HPV infections

Characterising the CI and CI-like carbonaceous chondrites using thermogravimetric analysis and infrared spectroscopy

The CI and CI-like chondrites provide a record of aqueous alteration in the early solar system. However, the CI-like chondrites differ in having also experienced a late stage period of thermal metamorphism. In order to constrain the nature and extent of the aqueous and thermal alteration, we have investigated the bulk mineralogy and abundance of H2O in the CI and CI-like chondrites using thermogravimetric analysis and infrared spectroscopy. The CI chondrites Ivuna and Orgueil show significant mass loss (28.5–31.8 wt.%) upon heating to 1000 °C due to dehydration and dehydroxylation of abundant phyllosilicates and Fe-(oxy)hydroxides and the decomposition of Fe-sulphides, carbonates and organics. Infrared spectra for Ivuna and Orgueil have a prominent 3-μm feature due to bound −OH/H2O in phyllosilicates and Fe-(oxy)hydroxides and only a minor 11-μm feature from anhydrous silicates. These characteristics are consistent with previous studies indicating that the CI chondrites underwent near-complete aqueous alteration. Similarities in the total abundance of H2O and 3 μm/11 μm ratio suggest that there is no difference in the relative degree of hydration experienced by Ivuna and Orgueil. In contrast, the CI-like chondrites Y-82162 and Y-980115 show lower mass loss (13.8–18.8 wt.%) and contain >50 % less H2O than the CI chondrites. The 3-μm feature is almost absent from spectra of Y-82162 and Y-980115 but the 11-μm feature is intense. The CI-like chondrites experienced thermal metamorphism at temperatures >500 °C that initially caused dehydration and dehydroxylation of phyllosilicates before partial recrystallization back into anhydrous silicates. The surfaces of many C-type asteroids were probably heated through impact metamorphism and/or solar radiation, so thermally altered carbonaceous chondrites are likely good analogues for samples that will be returned by the Hayabusa-2 and OSIRIS-REx missions

In Vitro Evaluation of a Soluble Leishmania Promastigote Surface Antigen as a Potential Vaccine Candidate against Human Leishmaniasis

International audiencePSA (Promastigote Surface Antigen) belongs to a family of membrane-bound and secreted proteins present in severalLeishmania (L.) species. PSA is recognized by human Th1 cells and provides a high degree of protection in vaccinated mice.We evaluated humoral and cellular immune responses induced by a L. amazonensis PSA protein (LaPSA-38S) produced in aL. tarentolae expression system. This was done in individuals cured of cutaneous leishmaniasis due to L. major (CCLm) or L.braziliensis (CCLb) or visceral leishmaniasis due to L. donovani (CVLd) and in healthy individuals. Healthy individuals weresubdivided into immune (HHR-Lm and HHR-Li: Healthy High Responders living in an endemic area for L. major or L. infantuminfection) or non immune/naive individuals (HLR: Healthy Low Responders), depending on whether they produce high orlow levels of IFN-c in response to Leishmania soluble antigen. Low levels of total IgG antibodies to LaPSA-38S were detectedin sera from the studied groups. Interestingly, LaPSA-38S induced specific and significant levels of IFN-c, granzyme B and IL-10 in CCLm, HHR-Lm and HHR-Li groups, with HHR-Li group producing TNF-a in more. No significant cytokine response wasobserved in individuals immune to L. braziliensis or L. donovani infection. Phenotypic analysis showed a significant increasein CD4+ T cells producing IFN-c after LaPSA-38S stimulation, in CCLm. A high positive correlation was observed between thepercentage of IFN-c-producing CD4+ T cells and the released IFN-c. We showed that the LaPSA-38S protein was able toinduce a mixed Th1 and Th2/Treg cytokine response in individuals with immunity to L. major or L. infantum infectionindicating that it may be exploited as a vaccine candidate. We also showed, to our knowledge for the first time, the capacityof Leishmania PSA protein to induce granzyme B production in humans with immunity to L. major and L. infantum infectio

Antigenic extracts of Leishmania braziliensis and Leishmania amazonensis associated with saponin partially protects BALB/c mice against Leishmania chagasi infection by suppressing IL-10 and IL-4 production

This study evaluated two vaccine candidates for their effectiveness in protecting BALB/c mice against Leishmania chagasiinfection. These immunogenic preparations were composed of Leishmania amazonensisor Leishmania braziliensisantigenic extracts in association with saponin adjuvant. Mice were given three subcutaneous doses of one of these vaccine candidates weekly for three weeks and four weeks later challenged with promastigotes of L. chagasiby intravenous injection. We observed that both vaccine candidates induced a significant reduction in the parasite load of the liver, while the L. amazonensisantigenic extract also stimulated a reduction in spleen parasite load. This protection was associated with a suppression of both interleukin (IL)-10 and IL-4 cytokines by spleen cells in response to L. chagasiantigen. No change was detected in the production of IFN-γ. Our data show that these immunogenic preparations reduce the type 2 immune response leading to the control of parasite replication

Passive and Low Energy Cooling 977 for the Built Environment

ABSTRACT The fresnel lens concept is suggested for solar control of the building in order to keep the illumination and the interior temperature at the comfort level. The collection of 60%-80% of the transmitted solar radiation through the fresnel lens on linear absorbers leaves the rest amount to be distributed in the interior space for the illumination and thermal building needs. The fresnel lenses can be combined with Thermal, Photovoltaic, or hybrid type Photovoltaic/Thermal small width absorbers to extract the concentrated solar radiation in the form of heat, electricity or both. Laboratory scale experimental results are presented in the paper, giving an idea about the application of this new optical system for lighting and cooling control of buildings

Transmission blocking vaccine studies in leishmaniasis: I Lipophosphogly can is a promising transmission blocking vaccine molecule against cutaneous leishmaniasis

(East African Medical Journal: 2001 78(2): 84-89