Insights into the role of bacteria in vitamin A biosynthesis: Future research opportunities

Abstract

Significant efforts have been made to address the hidden hunger challenges due to iron, zinc, iodine, and vitamin A since the beginning of the 21st century. Prioritizing the vitamin A deficiency (VAD) disorders, many countries are looking for viable alternative strategies such as biofortification. One of the leading causes of VAD is the poor bioconversion of β-carotene into retinoids. This review is focused on the opportunities of bacterial biosynthesis of retinoids, in particular, through the gut microbiota. The proposed hypothesis starts with the premise that an animal can able to store and timely convert carotenoids into retinoids in the liver and intestinal tissues. This theory is experimental with many scientific insights. The syntrophic metabolism, potential crosstalk of bile acids, lipocalins and lipopolysaccharides of gut microbiota are reported to contribute significantly to the retinoid biosynthesis. The gut bacteria respond to these kinds of factors by genetic restructuring driven mainly by events like horizontal gene transfer. A phylogenetic analysis of β-carotene 15, 15′-mono (di) oxygenase enzymes among a selected group of prokaryotes and eukaryotes was carried out to validate the hypotheses. Shedding light on the probiotic strategies through non-genetically modified organism such as gut bacteria capable of synthesizing vitamin A would address the VAD disorders.     

A Quarter of a Century of Progress to Prevent Vitamin A Deficiency Through Supplementation

A quarter of century has passed since FRI published its first comprehensive review on vitamin A deficiency (VAD) and its prevention. At the time, the major impetus to prevent VAD was to reduce xerophthalmia in preschool children. Today, we have a broader understanding of the public health implications of VAD, with disorders including xerophthalmia, mortality, severe infection, and anemia in preschool children and pregnant women. While deficiency affects most developing countries, nearly half of all deficient children and women live in Southern Asia. Prevention has made substantial strides. High potency vitamin A supplementation (with 200,000 IU) remains a prophylactic mainstay, delivered through fixed facilities, enhanced outreach activities, and national child health day campaigns twice annually. Surprisingly, the costs of semi-annual delivery of vitamin A have changed little over the years, with new cost estimates remaining comparable to earlier figures of US ～$0.50 per child per year. Emerging is the potential to reduce infant mortality by ～20% in Southern Asia by giving a single, oral, 50,000 IU dose of vitamin A to newborns. While ～500 million vitamin A capsules are routinely distributed worldwide each year to achieve effective control, progress has been slower with efforts to improve diet on a purposeful global public health scale. Future advances through effective dietary diversification and various means of food fortification will be required before periodic supplementation can be phased down as a major population strategy for controlling vitamin A deficiency.     

维生素A（VA）与人体健康的关系

维生素A（VA）是人和动物所必需的一种脂溶性维生素。主要介绍了维生素A的概况、生理功能、缺乏和过量摄入所引起的症状等,意在说明VA的过量摄入会对机体造成危害。     

Recent advances in banana (musa spp.) biofortification to alleviate vitamin A deficiency

Abstract

Vitamin A deficiency (VAD) is one of the most prevalent micronutrient deficiencies that disproportionately affects low income populations in developing countries. Traditional breeding and modern biotechnology have significant potential to enhance micronutrient bioavailability in crops through biofortification. Bananas (Musa spp.) are economically important fruit crops grown throughout tropical and sub-tropical regions of the world where VAD is most prevalent. Some banana genotypes are rich in provitamin A carotenoids (pVACs), providing an opportunity to use bananas as a readily available vehicle for provitamin A delivery. This review summarizes the progress made in carotenoid research in bananas relative to banana diversity and the use of conventional breeding and transgenic approaches aimed at banana biofortification to address vitamin A deficiency. Existing reports on sampling strategies, pVAC retention and bioavailability are also evaluated as essential components for a successful banana biofortification effort. The wide variability of pVACs reported in banana cultivars coupled with recent advances in unraveling the diversity and genetic improvement of this globally important but often-neglected staple fruit crop underscores their importance in biofortification schemes.     

类胡萝卜素的生物利用率

本文论述了作为维生素A前体的类胡萝卜素在体内的吸收代谢过程、类胡萝卜素生物利用率的定义、影响生物利用率的因素以及测定新方法。     

植物源天然产物对黄曲霉和黄曲霉毒素B_1的抑制作用研究进展

黄曲霉毒素B1(aflatoxin B1,AFB1)是化学物质中致癌性最强的一种,对人和动物的健康具有极大的威胁,尤其是对肝脏的损害。AFB1是谷物和粮油中最为多见的真菌毒素,危害性也最强,长期低剂量的摄入AFB1除了会导致肝脏损伤和诱发肝癌之外,也会损害人体的其他器官。因此,能够有效防护人体免遭AFB1损伤的功能食品和新型保健药物已成为研究重点。近年来,天然产物因其具有生物活性显著、副作用小、多靶点等优点而备受关注,多种植物源天然产物已被报道能够抑制黄曲霉的生长产毒和AFB1的毒性作用。该文主要综述了植物源天然产物对黄曲霉生长产毒和AFB1毒性作用的抑制作用以及其相关抑制机制,为进一步开展AFB1毒性损伤的防护研究工作,开发能降低AFB1对人和动物的毒性损伤的新型保健药物和功能食品提供参考。     

Evaluating Global Barriers to the Use of Red Palm Oil as an Intervention Food to Prevent Vitamin A Deficiency

Abstract: Vitamin A deficiency (VAD) is an important cause of blindness and premature death. Red palm oil (RPO) is the richest food source of VA‐forming carotenoids. RPO carotenoid concentration and bioavailability were evaluated and this data used to estimate the amount of RPO needed to meet VA requirements. Amounts ranged from 6.7 to 29.2 g/d (1.5 to 6.5 tsp/d), which are easily consumed. The amount of RPO needed to supply recommended dietary intakes of VA for all 208100000 individuals most in danger for VAD worldwide for 1 y is 0.80 million metric tons, a fraction of annual world palm oil production. Despite its abundance, RPO has seldom been used for VAD prevention on a national level. Pareto charts were constructed to highlight the variables that influence the ability of RPO to prevent VAD on the national level. The most important variable by far was refining method. Most refining methods are designed to remove color and flavor from RPO, resulting in a bland product that lacks carotenoids. Thus, the important barriers to the use of RPO as a food‐based intervention to prevent VAD appear to be that: (1) RPO requires refining, limiting its profitability and availability for small farmers. (2) The goal of most refining methods is to create a low‐cost bland, odorless, and colorless fat which requires removal of carotenoids. (3) Cost, since RPO use competes with high‐dose VA supplements, which are heavily subsidized. It appears that RPO could prevent VAD in many food‐deficit countries if carotenoids were conserved during oil refining, and costs were low enough to make it an attractive alternative to nutritional supplements.     

食源性植物多糖改善糖尿病引发肾损伤的研究进展

糖尿病是一类由于胰岛素分泌缺陷或其生物作用受损而引起的代谢性疾病, 主要表现特征为高血糖。人体长期处于高血糖状态, 会导致各种组织和器官受损, 尤其是是眼、肾、心脏、血管和神经等的慢性损伤或者功能障碍。植物多糖, 是植物细胞代谢产生的聚合度超过10个的聚糖。许多食源性植物多糖具有一定的生物活性, 能够调节血糖水平, 因此植物多糖在医学、食品和餐饮领域已得到了较为广泛的应用。本文对具有改善糖尿病引发肾损伤功能的食源性植物多糖的来源及功效进行整理, 综述了食源性植物多糖改善糖尿病肾损伤的作用机制, 并对未来食源性植物多糖在改善糖尿病肾损伤领域的应用前景进行展望。     

Production of β-Cryptoxanthin, a Provitamin-A Precursor, by Flavobacterium Lutescens

ABSTRACT:  Vitamin A deficiency (VAD) is the leading cause of preventable blindness in children and raises the risk of disease and death from severe infections. Some plant foods contain darkly colored pigments with provitamin A activity (α-carotene, β-carotene, and β-cryptoxanthin) that can be converted to vitamin A. In this work, a process is described for β-cryptoxanthin production by Flavobacterium lutescens ITCB008 using fermentation technology. The critical process variables associated with batch fermentation production in a stirred vessel were evaluated and quantified based on experimental design strategies. An ad hoc mathematical model was constructed and used to identify the operating conditions (agitation 190 rpm, aeration 0.086 VVM [air volume/broth volume per minute], and temperature 27.6 °C, pH 7.3) that maximized β-cryptoxanthin synthesis (770 mg of β-cryptoxanthin/kg biomass; dry weight) in a short processing time (28 h). In addition, downstream-processing studies were performed revealing that extraction of β-cryptoxanthin can be achieved with a polar solvent that produces cell lysis, such as methanol or ethanol, in only 1 step. High performance liquid chromatography analysis showed that β-cryptoxanthin represents nearly 95% of the total carotenoid content in the obtained product. The process described could be a commercial alternative for producing β-cryptoxanthin additives, as supplement in food formulation, thus assisting VAD prevention.     

抗菌肽在调节免疫和维持肠道健康中的作用

抗菌肽是生物体产生的一类具有抗菌作用的活性肽,具有安全、不易产生耐药性等优点。抗菌肽不仅可以抑制腐败菌和致病菌的生长,还有助于提高机体免疫力和改善肠道健康,广泛应用于医药、食品、农业等多个领域。肠道除了发挥消化吸收作用外,还是机体最大的免疫器官,对维持人体健康发挥着至关重要的作用。近年来,抗菌肽在调节免疫和维持肠道健康中的作用备受关注。本文综述了抗菌肽在调节免疫和维持肠道健康中的作用,提出了抗菌肽的研究发展新方向,为拓宽抗菌肽的研究与应用领域,发掘抗菌肽的健康功效提供参考。     

Chrysophanol induces necrosis through the production of ROS and alteration of ATP levels in J5 human liver cancer cells

Anthraquinone compounds have been shown to induce apoptosis in different cancer cell types. Effects of chrysophanol, an anthraquinone compound, on cancer cell death have not been well studied. The goal of this study was to examine if chrysophanol had cytotoxic effects and if such effects involved apoptosis or necrosis in J5 human liver cancer cells. Chrysophanol induced necrosis in J5 cells in a dose‐ and time‐dependent manner. Non‐apoptotic cell death was induced by chrysophanol in J5 cells and was characterized by caspase independence, delayed externalization of phosphatidylserine and plasma membrane disruption. Blockage of apoptotic induction by a general caspase inhibitor (z‐VAD‐fmk) failed to protect cells against chrysophanol‐induced cell death. The levels of reactive oxygen species production and loss of mitochondrial membrane potential (ΔΨ_m) were also determined to assess the effects of chrysophanol. However, reductions in adenosine triphosphate levels and increases in lactate dehydrogenase activity indicated that chrysophanol stimulated necrotic cell death. In summary, human liver cancer cells treated with chrysophanol exhibited a cellular pattern associated with necrosis and not apoptosis.     

基于数字化三维人体模型的旗袍定制设计

为更好地实现数字化定制设计在服装行业中的应用,解决定制类贴体服装传统样板生成方法所存在的合体性差、设计制板周期长等问题,提出一种基于三维可视化技术与逆向工程技术进行旗袍定制设计方法。首先,应用三维虚拟设计平台,将三维人体扫描获取的人体23个特征部位数据进行人体模型参数化设置;然后,通过在人体模型的4个关键部位加入松量,构建出“带贴体松量”的特征人体模型,并在此人体模型上进行三维旗袍造型及内部分割设计;最后,将三维旗袍曲面自动展平得到二维样板,并将二维样板制成成衣进行主观评价。评价结果表明,成衣主观测评指数达到4.0分以上,该方法可有效进行贴体服装设计及样板自动生成。     

Advances of Research on Glycinin and β-Conglycinin: A Review of Two Major Soybean Allergenic Proteins

Being an important crop, soybean is widely used in the world and plays a vital role in human and animal nutrition. However, it contains several antinutritional factors (ANFs) including soybean agglutinin, soybean protease inhibitors, soybean allergenic proteins, etc., that may result in poor food utilization, decreased growth performance, and even disease. Among these ANFs, soybean allergenic proteins can lead to allergic reactions in human and animals, which has become a public problem all over the world, but our knowledge on it is still inadequate. This paper aims to provide an update on the characteristics, detection or exploration methods, and in vivo research models of soybean allergenic proteins; especially glycinin and β-conglycinin are deeply discussed. Through this review, we may have a better understanding on the advances of research on these two soybean allergenic proteins. Besides, the ingredient processing used to reduce the allergenicity of soybean is also reviewed.     

Effect of taurine on toxicity of vitamin A in rats

A study was undertaken to investigate the effect of taurine on the toxicity of vitamin A in male wistar rats. The rats were divided into six groups and fed different diets with or without supplements of 5% taurine and 25,000–50,000 (IU) vitamin A for 2 months. It was found that the body weight of rats, the ratios of liver and kidney weight to body weight, and the level of glutathione in the liver were decreased with increasing the dose of vitamin A. The levels of vitamin A in the liver and kidney, the levels of thiobarbituric acid-reactive substances (TBARS) in the plasma and liver, the activities of aspartate transaminase (AST) and alanine transaminase (ALT) in the plasma, and the levels of blood urea nitrogen (BUN) and creatinine in the plasma of rats were increased with the increasing dose of vitamin A. Hence, symptoms of vitamin A toxicity in rats included loss of body weight, hepatotoxicity and nephrotoxicity. However, these toxic effects of vitamin A were significantly reduced when the rats were fed the diet with the supplement of taurine. Furthermore, the level of vitamin A in the serum of rats treated with taurine and vitamin A was higher than that of rats treated with vitamin A alone. This indicated that taurine might play a role in reducing the toxic effect of vitamin A in rats.     

抗菌肽应用于食品中的研究现状及面临的挑战

食品安全问题一直为人们所关注,其中微生物污染是导致食品腐败变质的主要原因。抗菌肽来源广泛,抑菌谱广,杀菌速度快,可以较好地控制食品中腐败微生物的滋生;对pH值、蛋白酶和热处理有较好的稳定性,在成分复杂的食品体系中有一定的适用性;由于其抑菌机理特殊,不易产生耐药性;部分具有抗氧化和提高免疫力等多种功能,对人体具有一定的保健作用。抗菌肽的以上特点满足了人们对新型防腐保鲜剂的多种需求,有望在食品工业上发挥重大作用。因此,在抗菌肽的生物学功能以及抗菌肽保鲜机理简单介绍的基础上,对抗菌肽应用于不同食品中的研究现况进行详细综述,最后对抗菌肽在食品中应用目前存在的问题和发展方向提供了思考。     

Predicting the Behaviour of Yersinia Enterocolitica and Listeria Monocytogenes in Italian Style Fresh Sausages under Drying Period

Italian style fresh sausage is a traditional pork product that is frequently consumed raw, usually after drying. So far, the prediction of the behaviour of microorganisms in varying environments has been carried out through separate growth or death models. The aim of this study is to show how to combine these, in order to describe the kinetics of Yersinia enterocolitica and Listeria monocytogenes in sausage during the drying period.During this time, the storage temperature and the pH are fairly constant, while the water activity decreases, being the primary cause of shifting the organisms’ kinetics from growth to inactivation. The water activity takes up values from growth (R_G), uncertainty (R₀) and death (R_D) regions. In the uncertainty region, neither growth nor death is predicted. Among the native flora, lactic acid bacteria may have significant effect on these kinetics.Here we show how to generate predictions for such scenarios, from data that are generated in constant environments. Thus the predictions in our dynamic environments are extrapolations and could be problematic if the environmental fluctuation is extreme. Our approach can be used to predict bacterial growth/death kinetics under temporal variation of storage environments, which is vital when assessing the safety of fresh sausage. We envisage similar applications to other RTE meat products, too.     

Mechanisms regulating follicle wave patterns in the bovine estrous cycle investigated with a mathematical model

A normal bovine estrous cycle contains 2 or 3 waves of follicle development, and ovulation takes place in the last wave. However, the biological mechanisms that determine whether a cycle has 2 or 3 waves have not been elucidated. In a previous paper, we described a mathematical model of the bovine estrous cycle that generates cyclical fluctuations of hormones, follicles, and corpora lutea in estrous cycles of approximately 21 d for cows with a normal estrous cycle. The parameters in the model represent kinetic properties of the system with regard to synthesis, release, and clearance of hormones and growth and regression of follicles and corpora lutea. The initial model parameterization resulted in estrous cycles with 3 waves of follicular growth. Here, we use this model to explore which physiological mechanisms could affect the number of follicular waves. We hypothesized that some of the parameters related to follicle growth rate or to the time point of corpus luteum regression are likely candidates to affect the number of waves per cycle. We performed simulations with the model in which we varied the values of these parameters. We showed that variation of (combinations of) model parameters regulating follicle growth rate or time point of corpus luteum regression can change the model output from 3 to 2 waves of follicular growth in a cycle. In addition, alternating 2- and 3-wave cycles occurred. Some of the parameter changes seem to represent plausible biological mechanisms that could explain these follicular wave patterns. In conclusion, our simulations indicated likely parameters involved in the mechanisms that regulate the follicular wave pattern, and could thereby help to find causes of declined fertility in dairy cows.     

The mathematical properties of the quasi-chemical model for microorganism growth-death kinetics in foods

Knowledge of the mathematical properties of the quasi-chemical model [Taub, Feeherry, Ross, Kustin, Doona, 2003. A quasi-chemical kinetics model for the growth and death of Staphylococcus aureus in intermediate moisture bread. J. Food Sci. 68 (8), 2530-2537], which is used to characterize and predict microbial growth-death kinetics in foods, is important for its applications in predictive microbiology. The model consists of a system of four ordinary differential equations (ODEs), which govern the temporal dependence of the bacterial life cycle (the lag, exponential growth, stationary, and death phases, respectively). The ODE system derives from a hypothetical four-step reaction scheme that postulates the activity of a critical intermediate as an antagonist to growth (perhaps through a quorum sensing biomechanism). The general behavior of the solutions to the ODEs is illustrated by several examples. In instances when explicit mathematical solutions to these ODEs are not obtainable, mathematical approximations are used to find solutions that are helpful in evaluating growth in the early stages and again near the end of the process. Useful solutions for the ODE system are also obtained in the case where the rate of antagonist formation is small. The examples and the approximate solutions provide guidance in the parameter estimation that must be done when fitting the model to data. The general behavior of the solutions is illustrated by examples, and the MATLAB programs with worked examples are included in the appendices for use by predictive microbiologists for data collected independently.     

α-生育酚酯类产品及其制备方法

生育酚酯类产品化学稳定性好，是维生素E系列产品的重要商品表现形式。生育酚酯种类很多，药理功能不尽相同。一些生育酚酯的生物活性比生育酚的高，有些生育酚酯更容易被人体吸收，还有一些生育酚酯则具有良好的表面活性。这些性质大大扩展了维生素E的应用领域，使之广泛应用于医药、食品、化妆品及饲料工业。