Nanobodies are highly valuable tools for numerous bioanalytical and biotechnical applications. Here, we report the characterization of a nanobody that binds a short peptide epitope with extraordinary affinity. Structural analysis reveals an unusual binding mode where the extended peptide becomes part of a β-sheet structure in the nanobody. This interaction relies on sequence-independent backbone interactions augmented by a small number of specificity-determining side chain contacts. Once bound, the peptide is fastened by two nanobody side chains that clamp it in a headlock fashion. Exploiting this unusual binding mode, we generated a novel nanobody-derived capture and detection system. Matrix-coupled nanobody enables the fast and efficient isolation of epitope-tagged proteins from prokaryotic and eukaryotic expression systems. Additionally, the fluorescently labeled nanobody visualizes subcellular structures in different cellular compartments. The high-affinity-binding and modifiable peptide tag of this system renders it a versatile and robust tool to combine biochemical analysis with microscopic studies.

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Tinea capitis continues to be a common problem of infancy and childhood, particularly among those living in unhygienic crowded conditions. The prevalence and aetiology of tinea capitis have not been well defined in Anambra state of Nigeria - hence the need to undertake this study. A total of 47,723 primary school children residing in different regions of the State was screened for tinea capitis between 2002 and 2005. Of this number, 4498 (9.4%) had tinea capitis. The highest prevalence of the disease occurred in the Southern region of the state (12.6%). Schools in urban areas recorded lower prevalence of the disease. Male : female prevalence ratio of 1.6 : 1 was recorded. Tinea capitis occurred significantly more in children below 10 years of age than in those above this age (chi(2 )= 3.178; P < 0.10). Of 502 isolates recovered in culture, Microsporum audouinii was the most prevalent (42%), followed by M. ferrugineum (17%) and Trichophyton mentagrophytes (16%). Four of the samples revealed spore head of Aspergillus spp. in direct sample microscopy. A total of 29 (6%) isolates was atypical forms. The majority (91%) of children with the lesion came from families of three or more children, living in crowded apartments. Results showed that tinea capitis remains an important public health problem in Anambra state of Nigeria.

Antibiotic-resistant S. aureus isolates were recovered from clinical and community settings in Nigeria. Insight about S. aureus in Nigeria may be used to improve antibiotic prescription methods and minimize the spread of antibiotic-resistant organisms in highly populated urban communities similar to Lagos, Nigeria.

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