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Complementary feeding of 6- to 24-month-old infants and young children with adequate, safe and developmentally appropriate food is essential to child health. Inappropriate complementary foods and feeding practices are linked to the high incidences of undernutrition among infant and young children in most developing countries, including Tanzania. Mycotoxin risk is an additional concern, given the documented presence of aflatoxin and fumonisin in food systems of Africa, especially maize and groundnut. In preparation for a trial of mycotoxin mitigation, we conducted focus group discussions and recipe trials to explore complementary foods and feeding practices in Kongwa, a rural district of central Tanzania. Sixty mothers of infants from 6 to 18 months of age in five villages across the district were purposefully sampled. During focus group discussions, mothers reported to mostly feed their children with cereal and groundnut-based foods as thin or thick porridges. The most common porridge preparations contained cereal (mostly, maize) ranging from 66.7% to 80.0% by weight and groundnuts from 7.7% to 33.3%. The ratio of cereal to groundnut ranged from 3:1 to 4:1. For the recipe trial sessions, mothers chose similar ingredients reported during discussions to prepare complementary foods. The reliance on maize and groundnuts in complementary foods predisposes the children to undernutrition and exposure to aflatoxins and fumonisins. These formative research results suggest multiple intervention points to improve complementary feeding and reduce mycotoxin exposure in this population, including education messages package on feeding practices, mycotoxin control practices and complementary food formulation., (© 2021 The Authors. Maternal & Child Nutrition published by John Wiley & Sons Ltd.)

Background: Under nutrition remains a serious problem among children in Sub-Saharan Africa. Analysing how diets composed of local foods could achieve nutritional goals for infants and young children in low-income settings is essential. The objective of this study was to analyse how local foods can be used rationally and to what extent these foods can be supplemented to achieve nutrient requirements for children aged 6 - 23 months in resource-poor settings., Methods: A cross-sectional study was carried out to estimate dietary intakes of 400 children aged 6-23 months using a 12-h weighed dietary record, 24-h dietary recalls, and 7-days food records. Anthropometric measurements on each subject were also taken. Analyses were done to establish the level of nutrient intake, and nutritional status of the study population using Microsoft Excel 2013 and ProPAN software version 2.0., Results: The results showed that the prevalence of stunting, wasting and underweight for children aged 6-23 months was 30-41%, 1.5-3% and 4-9%, respectively. In addition, the results showed that diets that were consumed by the subjects comprised of local foods met vitamin A, vitamin C, protein and energy requirements for children aged 6-23 months. However, the extent of deficit in iron, zinc and calcium in baseline diets was large and difficult to meet under the existing feeding practices., Conclusions: The study shows that local foods in the study area have a potential to achieve recommended dietary intakes of some essential nutrients, and that interventions are needed to meet the required amount of iron, zinc and calcium for children aged 6-23 months. The interventions we propose here may encourage changes in traditional feeding habits and practices of the target population. Possible intervention options are (1) supplementation of local foods with nutrient-dense foods that are not normally consumed in the locality (2) providing new avenues for increasing the production and wide consumption of local nutrient-dense foods, or optimizing the way local diets are constituted so as to achieve nutrient recommendations for infants and young children.

In the skin of fire-bellied toads (Bombina species), an aminoacyl-L/D-isomerase activity is present which catalyses the post-translational isomerization of the L- to the D-form of the second residue of its substrate peptides. Previously, this new type of enzyme was studied in some detail and genes potentially coding for similar polypeptides were found to exist in several vertebrate species including man. Here, we present our studies to the substrate specificity of this isomerase using fluorescence-labeled variants of the natural substrate bombinin H with different amino acids at positions 1, 2 or 3. Surprisingly, this enzyme has a rather low selectivity for residues at position 2 where the change of chirality at the alpha-carbon takes place. In contrast, a hydrophobic amino acid at position 1 and a small one at position 3 of the substrate are essential. Interestingly, some peptides containing a Phe at position 3 also were substrates. Furthermore, we investigated the role of the amino-terminus for substrate recognition. In view of the rather broad specificity of the frog isomerase, we made a databank search for potential substrates of such an enzyme. Indeed, numerous peptides of amphibia and mammals were found which fulfill the requirements determined in this study. Expression of isomerases with similar characteristics in other species can therefore be expected to catalyze the formation of peptides containing D-amino acids.

d-amino acids are present in some peptides from amphibian skin. These residues are derived from the corresponding L-amino acids present in the respective precursors. From skin secretions of Bombinae, we have isolated an enzyme that catalyzes the isomerization of an L-Ile in position 2 of a model peptide to D-allo-Ile. In the course of this reaction, which proceeds without the addition of a cofactor, radioactivity from tritiated water is incorporated into the second position of the product. The amino acid sequence of this isomerase could be deduced from cloned cDNA and genomic DNA. After expression of this cDNA in oocytes of Xenopus laevis, isomerase activity could be detected. Polypeptides related to the frog skin enzyme are present in several vertebrate species, including humans.

From skin secretions of Bombina variegata and Bombina bombina, we isolated a small protein termed Bv8. The sequence of its 77 amino acids was established by peptide analysis and by cDNA cloning of the Bv8 precursor. Bv8 stimulates the contraction of the guinea-pig ileum at nanomolar concentrations. The contraction is not inhibited by a variety of antagonists. Injection of a few micrograms of Bv8 into the brain of rats elicits, as assessed by the tail-flick test and paw pressure threshold, a marked hyperalgesia which lasts for about 1 h. Bv8 is related to protein A, a component of the venom of the black mamba. After i.c.v. injection, protein A is even more active than Bv8 in inducing hyperalgesia.

The cellular and structural properties and binding capabilities of a lipocalin expressed in the early neural plate of Xenopus laevis embryos and the adult choroid plexus have been investigated. It was found that this lipocalin, termed Xlcpl1, binds retinal at a nanomolar concentration, retinoic acid in the micromolar range, but does not show binding to retinol. Furthermore, this protein also binds D/L thyroxine. The Xlcpl1 cDNA was expressed in cell culture using the vaccinia virus expression system. In AtT20 cells, Xlcpl1 was secreted via the constitutive secretory pathway. We therefore assume that cpl1 binds retinaldehyde during the transport through the compartments of the secretory pathway that are considered to be the storage compartments of retinoids. Therefore, cpl1-expressing cells will secrete the precursors of active retinoids such as retinoic acid isomers. These retinoids may enter the cytosol by diffusion or receptor-controlled mechanisms, as has been shown for exogenously applied retinoids. Based on these data, it is suggested that cpl1 is an integral member of the retinoid signaling pathway and, therefore, it plays a key role in pattern formation in early embryonic development.

From skin secretions of the European frog Bombina bombina, a new peptide has been isolated that contains 60 amino acids, including 10 cysteine residues. Its sequence was determined by automated Edman degradation and confirmed by analysis of the cDNA encoding the precursor. A search in the databanks demonstrated that the pattern of cysteine residues in this skin peptide is similar to the ones found in protease inhibitors from Ascaris and in a segment of human von Willebrand factor. The 3D structure of the trypsin inhibitor from Ascaris suum could be used as a template to build a model of the amphibian peptide. In addition, we have demonstrated that this constituent of skin secretion is indeed an inhibitor of trypsin and thrombin, with K(i) values in the range of 0.1 to 1 microM. The new peptide was thus named BSTI for Bombina skin trypsin/thrombin inhibitor.

It has previously been shown that rat liver microsomes contain a proteolytic enzyme that cleaves honeybee prepromelittin to yield promelittin. This enzyme has now been further purified by centrifugation on a sucrose-deoxycholate gradient and then reconstituted into phospholipid vesicles. Incubation of prepromelittin with vesicles in the presence of melittin yields, in addition to promelittin, a hydrophobic peptide. The latter could be isolated by extraction with l-butanol and paper electrophoresis in 30% formic acid and was shown to be intact signal peptide by analysis of peptic fragments and automated Edman degradation. The microsomal enzyme is thus an endoprotease that hydrolyzes prepromelittin exclusively at the pre-pro junction. The precision of this cleavage of an insect preprotein by a rat liver enzyme indicates that we are dealing with the ubiquitous eukaryotic signal peptidase.

A dipeptidyl aminopeptidase has been purified to apparent homogeneity from skin secretion of Xenopus laevis. This enzyme is a glycoprotein with a molecular mass of about 98 kDa. It hydrolyzes a variety of dipeptidyl-p-nitroanilides and oligopeptides containing proline, alanine or glycine as the second amino acid and is inhibited by diisopropylfluorophosphate. The pH optimum was found to be around 8, while at pH 6, substrates were cleaved at about one-third of the maximal rate. This dipeptidyl aminopeptidase has the specificity required for the cleavage of amino-terminal extensions preceding the sequence of caerulein and xenopsin in their respective precursors.

The emission maximum of the single tryptophan residue of melittin was measured in the presence of phosphatidylethanolamine liposomes and Escherichia coli cytoplasmic membranes. In both cases, the fluorescence maximum was shifted to shorter wavelengths indicating a transfer of the indole ring to an apolar environment. E. coli membranes were labelled in position 2 of their phospholids with [14C]oleic acid. These membranes were used for measuring the activity of an endogenous phospholipase A2. A slow hydrolysis is observed, which can be accelerated by adding melittin. The extent of the stimulation depends on the molar ratio of melittin to membrane phospholipid. Under suitable conditions, the initial rate of hydrolysis is six to seven times higher in the presence than in the absence of melittin. The action of the phospholipase A2 from bee venom is also stimulated by melittin. An identical stimulation was observed with either E. coli membranes or pure phosphatidylethanolamine liposomes as substrate.

The biosynthesis of the peptides caerulein and PGLa in granular skin glands of Xenopus laevis proceeds through a pathway that involves discrete morphological rearrangements of the entire secretory compartment. Immunocytochemical localization of these peptides during gland development indicates that biosynthetic precursors are synthesized in intact secretory cells, whereas posttranslational processing requires morphological reorganization to a vacuolated stage. The bulk of the processed secretory material is then stored in vacuolae-derived storage granules. In the mature gland, storage granules are still formed at a low level. However, in this case processing takes place in a distinct cytoplasmic structure, the multicored body, which we suggest to be functionally equivalent to vacuolae. When granular glands regenerate after having lost all their storage granules upon strong stimuli, another morphological pathway is used. 2 wk after gland depletion, secretory cells become arranged in a monolayer that covers the luminal surface of the gland. Storage granules are formed continuously within these intact secretory cells. Here, precursor processing does not require a vacuolated stage as in newly generated glands but occurs in multicored bodies. Most storage granules seem to be formed in the third week of regeneration. The high biosynthetic activity is also reflected by the high activity of the putative processing enzyme dipeptidyl aminopeptidase during this period of regeneration.