White-gutted soldiers: simplification of the digestive tube for a non-particulate diet in higher Old World termites (Isoptera: Termitidae)

Previous observations have noted that in some species of higher termites the soldier caste lacks pigmented particles in its gut and, instead, is fed worker saliva that imparts a whitish coloration to the abdomen. In order to investigate the occurrence of this trait more thoroughly, we surveyed a broad diversity of termite specimens and taxonomic descriptions from the Old World subfamilies Apicotermitinae, Cubitermitinae, Foraminitermitinae, Macrotermitinae, and Termitinae. We identified 38 genera that have this “white-gutted” soldier (WGS) trait. No termite soldiers from the New World were found to possess a WGS caste. Externally, the WGS is characterized by a uniformly pale abdomen, hyaline gut, and proportionally smaller body-to-head volume ratio compared with their “dark-gutted” soldier (DGS) counterparts found in most termitid genera. The WGS is a fully formed soldier that, unlike soldiers in other higher termite taxa, has a small, narrow, and decompartmentalized digestive tube that lacks particulate food contents. The presumed saliva-nourished WGS have various forms of simplified gut morphologies that have evolved at least six times within the higher termites

THE EFFECT OF INCORPORATING NUTRIENT-DENSE NATIVE AFRICAN PLANT MATERIALS ON THE BIOACCESSIBILITY OF PROVITAMIN A CAROTENOIDS FROM COMPOSITE CEREAL-BASED FOOD PRODUCTS

Vitamin A deficiency is the leading cause of childhood blindness affecting over 190 million preschool children around the world where the highest rates are found in Sub-Saharan Africa (1). The coexistence of this deficiency with shortfalls in iron and zinc has resulted in a shift in intervention strategies from single targeted approach to broader diet diversification. As a result, food-based strategies leveraging local nutrient-dense plants as natural fortificants have gained significant interest for their potential to simultaneously address multiple micronutrient, and in some instances macronutrient, deficiencies. However, the efficacy of such approach depends upon several factors including knowledge on the nutritional composition of native plant materials as well as strategies for their incorporation into staple consumer products. Additionally, there is lack of information on impact of concurrent introduction of mineral and provitamin A rich plants on the stability and bioavailability of each individual nutrients including changes in these factors over extended periods of exposure. This is a key point considering that many of these materials are reported to have potential inhibitors of carotenoid absorption (minerals, fiber and phenolics).To address these research gaps, this dissertation focuses on three areas including 1) micronutrient, phytochemical and polysaccharide characterization of three commercially available native micronutrient dense African plant materials [Adansonia digitata (baobab), Moringa Oleifera (moringa) and Hibiscus Sabdariffa (hibiscus)] that have been targeted for use as natural iron fortificants; 2) determination of the impact of these materials on the bioaccessibility and intestinal uptake of provitamin A carotenoids from model composite cereal products and 3) assess the effect of longer term exposure to baobab and moringa on provitamin A carotenoid absorption and cellular differentiation biomarkers of human intestinal Caco-2 cells to better understand the potential impacts of extended exposure periods on long term micronutrient uptake. Characterization of the plant fortificants focused on understanding both nutritive components and potential limiters of carotenoid bioavailability. Baobab, moringa and hibiscus all were found to contain key phytochemical and polysaccharide components that could be leveraged as nutritional and function ingredients. The relatively higher levels of lutein (57  4.6 g/g), zeaxanthin (11  0.1g/g) and -carotene (20  2 g/g) in moringa leaf powder support the notion that this plant material can be used as a source of provitamin A and non-provitamin A carotenoids. Phenolic analysis revealed the presence of substantial amounts of flavan-3-ols (1234  16 mg/100g) in baobab, anthocyanins (2001  56 mg/100g) in hibiscus, and flavonols (5352  139 mg/100g) in moringa leaf powder. Polysaccharide analysis demonstrated that the primary monosaccharide in baobab was found to be xyloglucan (47 %) which is in agreement with the tentative identification Xyloglucans (hemicellulosic polysaccharide) based on linkage analysis. Hibiscus was found to contain similar amounts of xylose (20%) and galactose (27%) supporting the presence of similar proportions of xyloglucans and pectic polysaccharides (type I, type II AG, RG I). The main monosaccharide in moringa was found to be galactose (36%) followed by glucose (23%) and linkage analysis revealed the presence of high proportions of pectic polysaccharides (type I, type II AG, RG I). These results provide insight into presence of potential enhancer or inhibitors of target micronutrient (provitamin A carotenoids or iron/zinc) bioavailability when used as functional and nutritional food ingredients.Subsequently, the impact of mineral-rich baobab formulated at levels relevant for iron fortification on the bioaccessibility of provitamin A carotenoids (proVAC) from composite millet porridges containing dried carrot and mango was assessed using in vitro digestion. Proportions of millet flour and plant materials were dry blended to deliver ~25% of the RDA for vitamin A(VA) and iron(Fe) as follows: decorticated extruded millet (Senegalese Souna var.) (40-60%), dried proVA rich carrot and mango blend (30%), and dried Fe and ascorbic acid rich Adansonia digitata (baobab) (0-25%). While there were no significant differences in proVAC bioaccessibility from porridge formulations with 5 and 15% baobab (18.8+/-2.0 and 18.8±2.0% respectively) as compared to control containing no mineral-rich plant (23.8 +/- 1.2%), 25% baobab resulted in a significant decrease (p(3.3-3.6% -carotene and 3.7-4.5% for -carotene) across all formulation. These results suggest that any potential negative effects of baobab inclusion may be limited to food matrix interactions and digestion. This was confirmed in separate experiments that with experiments on baobab and carotenoid blends showing that digested baobab did not affect carotenoid absorption by Caco-2 cells. Overall these data support the notion that that modest inhibition of carotenoid bioaccessibility by baobab may not significantly limit carotenoid delivery from composite porridges. Furthermore, bioaccessible provitamin A content of a serving (200 g) of composite porridges can provide 27 - 48% of the RDA of vitamin A for children 1-3 years of age. Finally, we evaluated the impact of long-term exposure to baobab and moringa digesta on Caco-2 cell differentiation biomarkers and provitamin A uptake to gain insight into how inclusion of these materials in to a daily diet may alter absorption and transport of nutrients or otherwise have potential negative effects on the intestine. Based on NMR analysis of intracellular metabolites in differentiating Caco-2 monolayers, significant alterations in specific osmotic pressure regulators, particularly glycerophosphocholine, taurine and myo-inositol were observed with repeated exposure to all treatment groups including the control (digested 0.9% saline solution). Changes in these metabolites levels have been linked with specific cellular function including protection against hyperosmotic stress and regulation of paracellular permeability of Caco-2 cells. Evaluation of carotenoid uptake comparing acute and acute on repeated exposure to treatment groups demonstrated that there was an overall significant reduction in carotenoid uptake with repeated exposure across all treatment groups including the control. Despite the reduction in carotenoid uptake, mRNA and protein levels of carotenoid transporters (CD-36, SR-B1 and FABP1) were not significantly altered with exposure through differentiation (except for SR-B1 protein levels). Decrease in SR-B1 levels may be due to bile acid accumulation from the digesta matrix which is known to regulate its own biosynthesis by a mechanism that involves the down-regulation SR-B1 expression to protect cells from cytotoxicity. Our results provide some insight into the impact of simulated gastrointestinal fluids alone on provitamin A uptake in this model system which are usually not taken into consideration in most Caco-2 cell studies. However, overall, these findings indicate that the introduction of baobab and moringa at levels relevant for delivery of meaningful levels of iron (15-23% RDA) should not have negative impacts on human intestinal function or carotenoid uptake over chronic use. Taken together, our findings indicate that the three native Africa plant materials selected for investigation in these studies can be important sources of key micronutrients (iron, zinc and provitamin A carotenoids) and have potential as natural fortificants with application in staple foods such as cereal porridges. Incorporation of these plant materials, do not appear to negatively affect carotenoid bioavailability although there is a potential for their interaction during micellarization of carotenoids during normal digestion. While in vivo studies evaluating the bioavailability of provitamin A carotenoids from such composite formulations are required, these data support the further exploration of such natural fortification strategies in addressing micronutrient deficiencies in local African communities. </p

Gut Microbiota&mdash;Campylobacter jejuni Crosstalk in Broiler Chickens: A Comprehensive Review

The interaction between gut microbiota and C. jejuni in the guts of broiler chickens is essential for the bacterium&rsquo;s growth and potential pathogenicity. Recent findings highlighted the significance of modifying gut microbiota in relation to higher C. jejuni colonization rates and improved immune responses. This study suggested that a varied and balanced microbiota aids in decreasing and preventing C. jejuni proliferation via mechanisms including competitive exclusion, the synthesis of antimicrobial peptides, and the modulation of the chicken immune response. C. jejuni demonstrates adaptability in the gut environment by encouraging the growth of beneficial bacteria while inhibiting others, improving the way it acquires nutrients, and modifying the transcriptional response of its virulence factors. The dynamic nature of these microbiota communities has caused differences in the results of how gut microbiota and C. jejuni proliferation interact. Understanding the relationships between gut microbiota and C. jejuni is critical for developing strategies to mitigate the impact of C. jejuni in broiler chickens. This review compiles information on the relationships between gut microbiota and C. jejuni proliferation in broiler chickens and offers commentary on how the findings could improve gut health and food safety

Mixed Berry Juice and Cellulose Fiber Have Differential Effects on Peripheral Blood Mononuclear Cell Respiration in Overweight Adults

Berries and other anthocyanin-rich foods have demonstrated anti-obesity effects in rodents and humans. However, the bioactive components of these foods and their mechanisms of action are unclear. We conducted an intervention study with overweight and obese adults to isolate the effects of different berry components on bioenergetics. Subjects consumed whole mixed berries (high anthocyanin, high fiber), pressed berry juice (high anthocyanin, low fiber), berry-flavored gelatin (low anthocyanin, low fiber), or fiber-enriched gelatin (low anthocyanin, high fiber) for one week prior to a meal challenge with the same treatment food as the pre-feed period. Peripheral blood mononuclear cells were collected 2 h after the meal challenge, and cellular respiration was assessed via high-resolution respirometry. The high-anthocyanin, low-fiber treatment (berry juice) and the low-anthocyanin, high-fiber treatment (fiber-enriched gelatin) had opposite effects on cellular respiration. In the fasted state, berry juice resulted in the highest oxygen-consumption rate (OCR), while fiber-enriched gelatin resulted in the highest OCR in the fed state. Differences were observed in multiple respiration states (basal, state 3, state 4, uncoupled), with the greatest differences being between the pressed berry juice and the fiber-enriched gelatin. Different components of berries, specifically anthocyanins/flavonoids and fiber, appear to have differential effects on cellular respiration.</jats:p

Mixed Berry Juice and Cellulose Fiber Have Differential Effects on Peripheral Blood Mononuclear Cell Respiration in Overweight Adults

Berries and other anthocyanin-rich foods have demonstrated anti-obesity effects in rodents and humans. However, the bioactive components of these foods and their mechanisms of action are unclear. We conducted an intervention study with overweight and obese adults to isolate the effects of different berry components on bioenergetics. Subjects consumed whole mixed berries (high anthocyanin, high fiber), pressed berry juice (high anthocyanin, low fiber), berry-flavored gelatin (low anthocyanin, low fiber), or fiber-enriched gelatin (low anthocyanin, high fiber) for one week prior to a meal challenge with the same treatment food as the pre-feed period. Peripheral blood mononuclear cells were collected 2 h after the meal challenge, and cellular respiration was assessed via high-resolution respirometry. The high-anthocyanin, low-fiber treatment (berry juice) and the low-anthocyanin, high-fiber treatment (fiber-enriched gelatin) had opposite effects on cellular respiration. In the fasted state, berry juice resulted in the highest oxygen-consumption rate (OCR), while fiber-enriched gelatin resulted in the highest OCR in the fed state. Differences were observed in multiple respiration states (basal, state 3, state 4, uncoupled), with the greatest differences being between the pressed berry juice and the fiber-enriched gelatin. Different components of berries, specifically anthocyanins/flavonoids and fiber, appear to have differential effects on cellular respiration