The use of a P. falciparum specific coiled-coil domain to construct a self-assembling protein nanoparticle vaccine to prevent malaria.

The parasitic disease malaria remains a major global public health concern and no truly effective vaccine exists. One approach to the development of a malaria vaccine is to target the asexual blood stage that results in clinical symptoms. Most attempts have failed. New antigens such as P27A and P27 have emerged as potential new vaccine candidates. Multiple studies have demonstrated that antigens are more immunogenic and are better correlated with protection when presented on particulate delivery systems. One such particulate delivery system is the self-assembling protein nanoparticle (SAPN) that relies on coiled-coil domains of proteins to form stable nanoparticles. In the past we have used de novo designed amino acid domains to drive the formation of the coiled-coil scaffolds which present the antigenic epitopes on the particle surface. Here we use naturally occurring domains found in the tex1 protein to form the coiled-coil scaffolding of the nanoparticle. Thus, by engineering P27A and a new extended form of the coiled-coil domain P27 onto the N and C terminus of the SAPN protein monomer we have developed a particulate delivery system that effectively displays both antigens on a single particle that uses malaria tex1 sequences to form the nanoparticle scaffold. These particles are immunogenic in a murine model and induce immune responses similar to the ones observed in seropositive individuals in malaria endemic regions. We demonstrate that our P27/P27A-SAPNs induce an immune response akin to the one in seropositive individuals in Burkina Faso. Since P27 is highly conserved among different Plasmodium species, these novel SAPNs may even provide cross-protection between Plasmodium falciparum and Plasmodium vivax the two major human malaria pathogens. As the SAPNs are also easy to manufacture and store they can be delivered to the population in need without complication thus providing a low cost malaria vaccine

Real-Time Cytotoxicity Assay for Rapid and Sensitive Detection of Ricin from Complex Matrices

BACKGROUND: In the context of a potential bioterrorist attack sensitive and fast detection of functionally active toxins such as ricin from complex matrices is necessary to be able to start timely countermeasures. One of the functional detection methods currently available for ricin is the endpoint cytotoxicity assay, which suffers from a number of technical deficits. METHODOLOGY/FINDINGS: This work describes a novel online cytotoxicity assay for the detection of active ricin and Ricinus communis agglutinin, that is based on a real-time cell electronic sensing system and impedance measurement. Characteristic growth parameters of Vero cells were monitored online and used as standardized viability control. Upon incubation with toxin the cell status and the cytotoxic effect were visualized using a characteristic cell index-time profile. For ricin, tested in concentrations of 0.06 ng/mL or above, a concentration-dependent decrease of cell index correlating with cytotoxicity was recorded between 3.5 h and 60 h. For ricin, sensitive detection was determined after 24 h, with an IC50 of 0.4 ng/mL (for agglutinin, an IC50 of 30 ng/mL was observed). Using functionally blocking antibodies, the specificity for ricin and agglutinin was shown. For detection from complex matrices, ricin was spiked into several food matrices, and an IC50 ranging from 5.6 to 200 ng/mL was observed. Additionally, the assay proved to be useful in detecting active ricin in environmental sample materials, as shown for organic fertilizer containing R. communis material. CONCLUSIONS/SIGNIFICANCE: The cell-electrode impedance measurement provides a sensitive online detection method for biologically active cytotoxins such as ricin. As the cell status is monitored online, the assay can be standardized more efficiently than previous approaches based on endpoint measurement. More importantly, the real-time cytotoxicity assay provides a fast and easy tool to detect active ricin in complex sample matrices

MscS-like mechanosensitive channels in plants and microbes

The challenge of osmotic stress is something all living organisms must face as a result of environmental dynamics. Over the past three decades, innovative research and cooperation across disciplines have irrefutably established that cells utilize mechanically gated ion channels to release osmolytes and prevent cell lysis during hypoosmotic stress. Early electrophysiological analysis of the inner membrane of Escherichia coli identified the presence of three distinct mechanosensitive activities. The subsequent discoveries of the genes responsible for two of these activities, the mechanosensitive channels of large (MscL) and small (MscS) conductance, led to the identification of two diverse families of mechanosensitive channels. The latter of these two families, the MscS family, consists of members from bacteria, archaea, fungi, and plants. Genetic and electrophysiological analysis of these family members has provided insight into how organisms use mechanosensitive channels for osmotic regulation in response to changing environmental and developmental circumstances. Furthermore, determining the crystal structure of E. coli MscS and several homologues in several conformational states has contributed to our understanding of the gating mechanisms of these channels. Here we summarize our current knowledge of MscS homologues from all three domains of life and address their structure, proposed physiological functions, electrophysiological behaviors, and topological diversity

Impacts of intensive dairy production on smallholder farm women in coastal Kenya

Welfare impacts of an intensive dairy technology package on women and their families are investigated on 32 smallholder crop-livestock farms in the sub-humid zone of Kilifi District, Coast Province, Kenya. Farms were stratified according to male or female extension contact. A female enumerator interviewed the wife or female head of household on each farm regarding her present and past household responsibilities and the effects of the intensive dairy enterprise on these duties and upon the welfare of the household. On three-quarters of the male contact farms, dairy operators were women. Across all farms, women performed half of all dairy-related activities, but only on female contact farms did income from the dairy enterprise accrue to women in proportion to their labor input. The equitable return of benefits to labor corresponded with better dairy unit performance on female contact farms, where women also indicated greater access to and autonomy over household resources and decision-making. Irrespective of extension contact, there was broad consensus among the women interviewed that intensive dairying has led to improved household welfare, primarily through increased household income and milk consumption. There was also wide agreement, however, that these gains have been achieved at the expense of more work for women. Women on female contact farms were observed spending dairy income on food for the household and childrens' schooling more often than their counterparts on male contact farms. Based on these and other findings, the study concludes that gender of the extension contact, dairy operator and farm owner were determinants of the intra-household impacts of intensive dairying on the smallholder farms in this study. Recommendations for design and delivery of livestock technologies for crop-based farming systems, with special emphasis on how to minimize negative impact on vulnerable household members, are inferred from study findings

An account of a recent outbreak of Marek\'s Disease in Kenya

Data was collected from a number of flocks following an outbreak of Marek's disease in Thika, Kiambu and Nairobi, in 1997. Clinically, the disease presented as a rapid emaciation and depression followed by death. Weekly point and cumulative mortalities were calculated in two of the flocks. Postmortem examination revealed, initially, an atrophy of the bursa of Fabricious. Later, there were turmours in a proportion of the birds. The tumours were observed in the heart muscle, the liver, intestines, and bursa of fabricious. Later, there were tumours in a proportion of birds. The tumours were observed in heart muscles, the liver, intestines, bursa of Fabricious and the skin. There was swelling, oedema and frequently ulceration of the proventriculus. The spleen was usually spotted and enlarged. Microscopically, lesions consisted of a mixture of both proliferative and necrotic lesions the suspected contributory causative factors were high field infections pressure, failure to vaccinate, vaccination failure and lack of quarantine and other disease control measures. Failure to institute effective control measures against the disease is likely to seriously affect the poultry industry in the country. The Kenya Veterinarian Vol. 21 2001: pp. 34-3

Evaluation of an empiric risk screening score to identify acute and early HIV-1 infection among MSM in Coastal Kenya.

We evaluated the University of North CarolinaMalawi Risk Screening Score (UMRSS) for detection of acute and early HIV-1 infection (AEHI) in a cohort of Kenyan MSM with approximately 8% annual HIV-1 incidence. Three components of the UMRSS (fever, diarrhea, and discordant rapid HIV tests) were also independent predictors of AEHI in our cohort. The predictive ability (area under the receiver operating characteristic curve, AUC) of the UMRSS was 0.79. A cohort-derived risk score consisting of six characteristics (fever, diarrhea, discordant rapid HIV tests, fatigue, age <30 years, and symptomatic sexually transmitted disease) had a higher AUC of 0.85. Screening for AEHI will have substantial transmission prevention benefits

Diagnosing acute and prevalent HIV-1 infection in young African adults seeking care for fever: a systematic review and audit of current practice.

Fever is a common complaint in HIV-1 infected adults and may be a presenting sign of acute HIV-1 infection (AHI). We investigated the extent to which HIV-1 infection was considered in the diagnostic evaluation of febrile adults in sub-Saharan Africa (SSA) through a systematic review of published literature and guidelines in the period 2003–2014. We also performed a detailed audit of current practice for the evaluation of febrile young adults in coastal Kenya. Our review identified 43 studies investigating the aetiology of fever in adult outpatients in SSA. While the guidelines identified recommend testing for HIV-1 infection, none mentioned AHI. In our audit of current practice at nine health facilities, only 189 out of 1173 (16.1%) patients, aged 18–29 years, were tested for HIV-1. In a detailed record review, only 2 out of 39 (5.1%) young adults seeking care for fever were tested for HIV-1, and the possibility of AHI was not mentioned. Available literature on adult outpatients presenting with fever is heavily focused on diagnosing malaria and guidelines are poorly defined in terms of evaluating aetiologies other than malaria. Current practice in coastal Kenya shows poor uptake of provider-initiated HIV-1 testing and AHI is not currently considered in the differential diagnosis