Biotechnology of Okpeye: A Nigerian Traditional Fermented Food Condiment

Most legumes and oil bean seeds used in condiment manufacture in Africa are inedible by nature. They contain antinutritional elements such indigestible oligosaccharides and phytate. Fermentation affects desired alterations by lowering anti-nutritional components and enhancing digestibility. Okpeye is a traditional West African seasoning prepared from Prosopis africana seed solid substrate fermentation. Many homes consider it as a family business because the preparation follows a passed-down habit from previous generations as an inexpensive source of plant protein. However, natural nature of the fermentation process raises concerns about the consistency, quality, and safety of the finished product. Because the seasoning is created on a small scale with less sophisticated equipment and manufacturing procedures, there are concerns about microbial safety. Thus, fermentation process and the range of microbial composition involved in Prosopis africana okpeye production were evaluated in this review. Potential spoilage agents, as well as biochemical and nutritional changes occurring during production of okpeye are gaining interest among researcher. This review highlights information that can help in developing starter cultures in a controlled fermentation process that ensures quality, longer shelf life, and microbiological safety.

C2 domain of synaptotagmin I associates with lipid rafts of plasma membrane

In this paper we report that the C2 domain of synaptotagmin I (syt I) could associate with lipid rafts of plasma membrane. We demonstrate that phosphatidylinositol 4,5-bisphosphate (PIP2) in the target membrane and Ca2+ are the key factors to enhance the raft association of the C2 domain. We also found that the raft association of the C2 domain could be fulfilled by either C2A or C2B alone, suggesting that their raft association might be complementary. Finally, we indicate that destroying lipid rafts or blocking syt I-raft association could significantly reduce the Ca2+-driven release of glutamates. Our data indicate that the raft association of the C2 domain might play an important role in the regulated exocytosis.

Mutations of nuclear localization signals in mNANOG generate dominant negative mutants

Mouse NANOG plays a critical role in maintaining self-renewal and pluripotency of embryonic stem cells.Yet,the precise mechanism of how mNANOG functions is still less known.Here,we report that mouse NANOG has two nuclear localization signals(NLS,RKQKMR and RMKCKR) which are responsible for the nuclear localization and transcriptional activity in the conserved homeobox domain.NLS mutants of mouse NANOG generate 3 mutants that are localized throughout the cells and lose the transactivation function.We further prove that all three NLS mutants may interact with the wild-type mouse NANOG like NANOG dimerization itself and inhibit the wild-type mouse NANOG activity,acting as dominant negative mutants.The NLS mutants of mouse NANOG may also inhibit activity of oct4 promoter in pluripotent cells,indicating that the NLS mutants can affect the endogenous mouse NANOG function in vivo.These data suggest that the NLS mutants of mouse NANOG may be used as a tool to regulate NANOG activity in pluripotent cells.

Secondary Structure of Holo-Enzyme and Apo-Enzyme of Aminoacylase Using CD and FTIR Spectroscopy

Aminoacylase is a dimeric metal enzyme containing one Zn2+-ion per subunit of active site.It is essential for the activity of enzyme.Fourier transform-infrared spectroscopy has been used for the studyon the secondary structure of holo-enzyme and ago-enzyme of aminoaeylase from pig kidney.Resolution en-hancement of the amide I secondary structure-sensitive overlapped component bands has been achieved bymeans of the Fourier self-deconvolution and the Fourier derivation.The effect of Zn2+-ion on the secondarystructure of aminoacylase was observed clearly.After the removal of Zn2+in aminoacylase,the extent of theordered structure was decreased markedly.It suggests that the conformation st or near the active site ofaminoacylase contains more ordered structures,and the presence of Zn2+helps to keep the conformation ofthe active site required for the catalysis of the enzyme.

Aminoacylase from pig kidney contains no disulfide bonds

Both non-reduced/reduced(NR/R)two-dimensional diagonal SDS-PAGE and NR/Rone-dimensional SDS-PAGE showed no disulfide bonds in aminoacylase from pig kidney.Eight andfour thiol groups were modified in the native enzyme by 2-chloromercuri-4-nitrophenol(MNP)andEllman’s reagent,5,5’-dithiobis(2-nitrobenzoic add)(DTNB),and another two and six thiol groupscould be exposed and modified in 7mol/L guanidine hydrochloride,respectively.The enzyme denaturedwith guanidine or urea was found to contain a total of ten thiol groups.This is in good agreement with therecently deduced amino acid sequence from cloned cDNA.It is therefore clear that no disulfide bridges existin aminoacylase from pig kidney.

The N-terminal domain is a transcriptional activation domain required for Nanog to maintain ES cell self-renewal

Nanog is a transcription factor identified by its ability to maintain the self-renewal of ES cells in the absence of leukemia inhibitory factor (LIF). Nanog protein contains an N-terminal domain (ND), a DNA-binding homeobox domain (HD) and a C-terminal domain (CD). We previously reported that the CD in Nanog is a transcriptional activation domain essential for the in vivo function of Nanog. Here we demonstrated that the ND in Nanog is also functionally important. Deletion of the ND reduces the transcriptional activity of Nanog on either artificial reporters or native Nanog promoters. This truncated Nanog is also less effective in regulating the endogenous Nanog target genes. Furthermore, the ND truncation disrupted the ability of Nanog to maintain ES cell self-renewal as well. We found that the ND is not required for the nuclear localization of Nanog. These results suggest that the regulation of endogenous pluripotent genes such as oct3/4 and rex-1 is required for the in vivo function of Nanog.