Evolution of the diacylglycerol lipases

Characterization of a Fatty Acid Amide Hydrolase (FAAH) in Hirudo Verbana

The endocannabinoid system plays a critical role in modulating both peripheral and central nervous system function. Despite being present throughout the animal kingdom, there has been relatively little investigation of the endocannabinoid system beyond traditional animal models. In this study, we report on the identification and characterization of a putative fatty acid amide hydrolase (FAAH) in the medicinal leech, Hirudo verbana. FAAH is the primary enzyme responsible for metabolizing the endocannabinoid signaling molecule arachidonoyl ethanolamide (anandamide or AEA) and therefore plays a critical role in regulating AEA levels in the nervous system. mRNA encoding Hirudo FAAH (HirFAAH) is expressed in the leech central nervous system (CNS) and sequence analysis suggests that this is an orthologue of FAAH-2 observed in vertebrates. Functionally, HirFAAH has serine hydrolase activity based on activity-based protein profiling (ABPP) studies using the fluorophosphonate probe TAMRA-FP. HirFAAH also hydrolyzes arachidonyl 7-amino, 4-methyl coumarin amide (AAMCA), a substrate specific to FAAH. Hydrolase activity during both the ABPP and AAMCA assays was eliminated by a mutation at a conserved catalytic serine. Activity was also blocked by the known FAAH inhibitor, URB597. Treatment of Hirudo ganglia with URB597 potentiated synapses made by the pressure-sensitive mechanosensory neuron (P cell), mimicking the effects of exogenously applied AEA. The Hirudo CNS has been a useful system in which to study properties of endocannabinoid modulation of nociception relevant to vertebrates. Therefore, this characterization of HirFAAH is an important contribution to comparative studies of the endocannabinoid system.

Characterization of a Fatty Acid Amide Hydrolase (FAAH) in Hirudo verbana

The endocannabinoid system plays a critical role in modulating both peripheral and central nervous system function. Despite being present throughout the animal kingdom, there has been relatively little investigation of the endocannabinoid system beyond the traditional animal model systems. In this study, we report on the identification and characterization of a fatty acid aminohydrolase (FAAH) in the medicinal leech, Hirudo verbana. FAAH is the primary enzyme responsible for metabolizing the endocannabinoid signaling molecule arachidonoyl ethanolamide (anandamide or AEA) and therefore plays a critical role in regulating AEA levels in the nervous system. This Hirudo FAAH (HirFAAH) is expressed in the leech central nervous system (CNS) and is an orthologue of FAAH-2 observed in vertebrates. Functionally, HirFAAH has serine hydrolase activity based on activity-based protein profiling (ABPP) studies using the fluorophosphonate probe TAMRA-FP. HirFAAH also hydrolyzes arachidonyl 7-amino, 4-methyl coumarin amide (AAMCA), a substrate specific to FAAH. Hydrolase activity during both the ABPP and AAMCA assays was eliminated by mutation at a conserved activity-binding site. Activity was also blocked by the known FAAH inhibitor, URB597. Treatment of Hirudo ganglia with URB597 potentiated synapses made by the pressure-sensitive mechanosensory neuron (P cell), mimicking the effects of exogenously applied AEA. The Hirudo CNS has been a useful system in which to study properties of endocannabinoid modulation of nociception relevant to vertebrates. Therefore, this characterization of HirFAAH is an important contribution to comparative studies of the endocannabinoid system.

Molecular Machinery of Lipid Droplet Degradation and Turnover in Plants

Lipid droplets (LDs) are important organelles conserved across eukaryotes with a fascinating biogenesis and consumption cycle. Recent intensive research has focused on uncovering the cellular biology of LDs, with emphasis on their degradation. Briefly, two major pathways for LD degradation have been recognized: (1) lipolysis, in which lipid degradation is catalyzed by lipases on the LD surface, and (2) lipophagy, in which LDs are degraded by autophagy. Both of these pathways require the collective actions of several lipolytic and proteolytic enzymes, some of which have been purified and analyzed for their in vitro activities. Furthermore, several genes encoding these proteins have been cloned and characterized. In seed plants, seed germination is initiated by the hydrolysis of stored lipids in LDs to provide energy and carbon equivalents for the germinating seedling. However, little is known about the mechanism regulating the LD mobilization. In this review, we focus on recent progress toward understanding how lipids are degraded and the specific pathways that coordinate LD mobilization in plants, aiming to provide an accurate and detailed outline of the process. This will set the stage for future studies of LD dynamics and help to utilize LDs to their full potential.

Rumen-protected glucose supplementation alters fecal microbiota and its metabolic profiles in early lactation dairy cows

INTRODUCTION

Negative energy balance (NEB) is the pathological basis of metabolic disorders in early lactation dairy cows. Rumen-protected glucose (RPG) is a feed additive to relieve NEB of cows in early lactation. The aims of the current study were to evaluate the impact of different doses of RPG supply on fecal microbiota and metabolome in early lactation dairy cows, and their correlation with each other.

METHODS

A total of 24 multiparous Holstein dairy cows in early lactation were randomly assigned to one of four treatments for the first 35 days of the early lactation period, as follows: control group, a basal diet without RPG (CON); low RPG, a basal diet plus 200 g/d RPG (LRPG); medium RPG, a basal diet plus 350 g/d RPG (MRPG); or HRPG, high RPG, a basal diet plus 500 g/d RPG (HRPG). After 35 days, fecal samples were obtained from cows in all groups individually and using 16S rRNA gene sequencing to evaluate their microbiotas, while their metabolites were evaluated through metabolomics.

RESULTS

As expected, Firmicutes and Bacteroidetes were the core bacteria phyla. After RPG supplementation, there were an increase in Firmicutes and a decrease in Bacteroidetes. MRPG increased the relative abundance of cellulolytic bacteria, including Ruminococcaceae_UCG-005, Lachnospiraceae_UCG-008, Lachnospiraceae_FCS020_group, and Ruminiclostridium_9, while it decreased the relative abundance of Alistipes, Prevotellaceae_UCG-003, and Dorea. RPG supplementation could regulate the carbohydrate metabolism and amino acid metabolism pathway significantly and relieve lipolysis in dairy cows. Correlation analysis of fecal microbiome and metabolome showed that some major differential bacteria were the crucial contributors to differential metabolites.

CONCLUSION

In conclusion, RPG supplementation can affect the fecal microbial components and microbial metabolism, and 350 g RPG might be the ideal dose as a daily supplement.

An overview on the conversion of glycerol to value-added industrial products via chemical and biochemical routes

Glycerol is a common by-product of industrial biodiesel syntheses. Due to its properties, availability, and versatility, residual glycerol can be used as a raw material in the production of high value-added industrial inputs and outputs. In particular, products like hydrogen, propylene glycol, acrolein, epichlorohydrin, dioxalane and dioxane, glycerol carbonate, n-butanol, citric acid, ethanol, butanol, propionic acid, (mono-, di-, and triacylglycerols), cynamoil esters, glycerol acetate, benzoic acid, and other applications. In this context, the present study presents a critical evaluation of the innovative technologies based on the use of residual glycerol in different industries, including the pharmaceutical, textile, food, cosmetic, and energy sectors. Chemical and biochemical catalysts in the transformation of residual glycerol are explored, along with the factors to be considered regarding the choice of catalyst route used in the conversion process, aiming at improving the production of these industrial products.

Carboxylesterase 2 induces mitochondrial dysfunction via disrupting lipid homeostasis in oral squamous cell carcinoma

OBJECTIVE

Oral squamous cell carcinoma (OSCC) is characterized by high recurrence and metastasis and places a heavy burden on societies worldwide. Cancer cells thrive in a changing microenvironment by reprogramming lipidomic metabolic processes to provide nutrients and energy, activate oncogenic signaling pathways, and manage redox homeostasis to avoid lipotoxicity. The mechanism by which OSCC cells maintain lipid homeostasis during malignant progression is unclear.

METHODS

The altered expression of fatty acid (FA) metabolism genes in OSCC, compared with that in normal tissues, and in OSCC patients with or without recurrence or metastasis were determined using public data from the TCGA and GEO databases. Immunohistochemistry was performed to examine the carboxylesterase 2 (CES2) protein level in our own cohort. CCK-8 and Transwell assays and an in vivo xenograft model were used to evaluate the biological functions of CES2. Mass spectrometry and RNA sequencing were performed to determine the lipidome and transcriptome alterations induced by CES2. Mitochondrial mass, mtDNA content, mitochondrial membrane potential, ROS levels, and oxygen consumption and apoptosis rates were evaluated to determine the effects of CES2 on mitochondrial function in OSCC.

RESULTS

CES2 was downregulated in OSCC patients, especially those with recurrence or metastasis. CES2^high OSCC patients showed better overall survival than CES2^low OSCC patients. Restoring CES2 expression reduced OSCC cell viability and suppressed their migration and invasion in vitro, and it inhibited OSCC tumor growth in vivo. CES2 reprogrammed lipid metabolism in OSCC cells by hydrolyzing neutral lipid diacylglycerols (DGs) to release free fatty acids and reduce the membrane structure lipid phospholipids (PLs) synthesis. Free FAs were converted to acyl-carnitines (CARs) and transferred to mitochondria for oxidation, which induced reactive oxygen species (ROS) accumulation, mitochondrial damage, and apoptosis activation. Furthermore, the reduction in signaling lipids, e.g., DGs, PLs and substrates, suppressed PI3K/AKT/MYC signaling pathways. Restoring MYC rescued the diminished cell viability, suppressed migratory and invasive abilities, damaged mitochondria and reduced apoptosis rate induced by CES2.

CONCLUSIONS

We demonstrated that CES2 downregulation plays an important role in OSCC by maintaining lipid homeostasis and reducing lipotoxicity during tumor progression and may provide a potential therapeutic target for OSCC.

(Wh)olistic (E)ndocannabinoidome-Microbiome-Axis Modulation through (N)utrition (WHEN) to Curb Obesity and Related Disorders

The discovery of the endocannabinoidome (eCBome) is evolving gradually with yet to be elucidated functional lipid mediators and receptors. The diet modulates these bioactive lipids and the gut microbiome, both working in an entwined alliance. Mounting evidence suggests that, in different ways and with a certain specialisation, lipid signalling mediators such as N-acylethanolamines (NAEs), 2-monoacylglycerols (2-MAGs), and N-acyl-amino acids (NAAs), along with endocannabinoids (eCBs), can modulate physiological mechanisms underpinning appetite, food intake, macronutrient metabolism, pain sensation, blood pressure, mood, cognition, and immunity. This knowledge has been primarily utilised in pharmacology and medicine to develop many drugs targeting the fine and specific molecular pathways orchestrating eCB and eCBome activity. Conversely, the contribution of dietary NAEs, 2-MAGs and eCBs to the biological functions of these molecules has been little studied. In this review, we discuss the importance of (Wh) olistic (E)ndocannabinoidome-Microbiome-Axis Modulation through (N) utrition (WHEN), in the management of obesity and related disorders.

Alpha/Beta-Hydrolase Domain-Containing 6: Signaling and Function in the Central Nervous System

Endocannabinoid (eCB) signaling plays an important role in the central nervous system (CNS). α/β-Hydrolase domain-containing 6 (ABHD6) is a transmembrane serine hydrolase that hydrolyzes monoacylglycerol (MAG) lipids such as endocannabinoid 2-arachidonoyl glycerol (2-AG). ABHD6 participates in neurotransmission, inflammation, brain energy metabolism, tumorigenesis and other biological processes and is a potential therapeutic target for various neurological diseases, such as traumatic brain injury (TBI), multiple sclerosis (MS), epilepsy, mental illness, and pain. This review summarizes the molecular mechanisms of action and biological functions of ABHD6, particularly its mechanism of action in the pathogenesis of neurological diseases, and provides a theoretical basis for new pharmacological interventions via targeting of ABHD6.

Sequence and structure-based method to predict diacylglycerol lipases in protein sequence

Lipase enzymes play a central role in biotechnology and the food industry. Diacylglyceride lipases (DAG) have received considerable attention due to their physiological significance and potential industrial usage. However, compared to the wide application of triacylglycerol (TAG) lipases, DAG lipases have a limited application due to their low thermostability and specific activity. The molecular basis of substrate specificity of DAG lipases remains elusive, making structure-guided engineering of TAG to DAG lipase difficult. Besides, the number of available DAG lipases is limited compared to TAG lipases. In the current study, we identified structural consensus motifs of DAG lipases that contribute to their DAG specificity on a structural comparison of DAG and TAG lipases. To find potential DAG lipases, sequence motifs and predicted secondary structures were used to screen millions of protein sequences and predict new DAG lipases. In total, 83 new putative DAG lipases were identified. The predicted DAG lipases were validated by expression of randomly chosen putative DAG lipases followed by functional assay for their DAG and TAG specific activity. The reported method is efficient and cost-effective for discovering new DAG lipases used in the food industry after the required characterization to meet potential application needs.

The Endocannabinoid System and Invertebrate Neurodevelopment and Regeneration

Cannabis has long been used for its medicinal and psychoactive properties. With the relatively new adoption of formal medicinal cannabis regulations worldwide, the study of cannabinoids, both endogenous and exogenous, has similarly flourished in more recent decades. In particular, research investigating the role of cannabinoids in regeneration and neurodevelopment has yielded promising results in vertebrate models. However, regeneration-competent vertebrates are few, whereas a myriad of invertebrate species have been established as superb models for regeneration. As such, this review aims to provide a comprehensive summary of the endocannabinoid system, with a focus on current advances in the area of endocannabinoid system contributions to invertebrate neurodevelopment and regeneration.

Integration of metabolomics and existing omics data reveals new insights into phytoplasma-induced metabolic reprogramming in host plants

Phytoplasmas are cell wall-less bacteria that induce abnormal plant growth and various diseases, causing severe economic loss. Phytoplasmas are highly dependent on nutrients imported from host cells because they have lost many genes involved in essential metabolic pathways during reductive evolution. However, metabolic crosstalk between phytoplasmas and host plants and the mechanisms of phytoplasma nutrient acquisition remain poorly understood. In this study, using metabolomics approach, sweet cherry virescence (SCV) phytoplasma-induced metabolite alterations in sweet cherry trees were investigated. A total of 676 metabolites were identified in SCV phytoplasma-infected and mock inoculated leaves, of which 187 metabolites were differentially expressed, with an overwhelming majority belonging to carbohydrates, fatty acids/lipids, amino acids, and flavonoids. Available omics data of interactions between plant and phytoplasma were also deciphered and integrated into the present study. The results demonstrated that phytoplasma infection promoted glycolysis and pentose phosphate pathway activities, which provide energy and nutrients, and facilitate biosynthesis of necessary low-molecular metabolites. Our findings indicated that phytoplasma can induce reprograming of plant metabolism to obtain nutrients for its own replication and infection. The findings from this study provide new insight into interactions of host plants and phytoplasmas from a nutrient acquisition perspective.

Tissue distribution of transcription for 29 lipid metabolism-related genes in Takifugu rubripes, a marine teleost storing lipid predominantly in liver

The tissue distribution pattern of lipid is highly diverse among different fish species. Tiger puffer has a special lipid storage pattern, storing lipid predominantly in liver. In order to better understand the lipid physiology in fish storing lipid in liver, the present study preliminarily investigated the tissue distribution of transcription for 29 lipid metabolism-related genes in tiger puffer, which are involved in lipogenesis, fatty acid oxidation, biosynthesis and hydrolysis of glycerides, lipid transport, and relevant transcription regulation. Samples of eight tissues, brain, eye, heart, spleen, liver, intestine, skin, and muscle, from fifteen juvenile tiger puffer were used in the qRT-PCR analysis. The intestine and brain had high transcription of lipogenic genes, whereas the liver and muscle had low expression levels. The intestine also had the highest transcription level of most apolipoproteins and lipid metabolism-related transcription factors. The transcription of fatty acid β-oxidation-related genes was low in the muscle. The peroxisomal fatty acid oxidation may dominate over mitochondrial β-oxidation in the liver and intestine of tiger puffer, and the MAG pathway probably predominates over the G3P pathway in re-acylation of absorbed lipids in the intestine. The intracellular glyceridases were highly transcribed in the brain, eye, and heart. In conclusion, in tiger puffer, the intestine could be a center of lipid metabolism whereas the liver is more likely a pure storage organ for lipid. The lipid metabolism in the muscle could also be inactive, possibly due to the very low level of intramuscular lipid.

One Pot Use of Combilipases for Full Modification of Oils and Fats: Multifunctional and Heterogeneous Substrates

Lipases are among the most utilized enzymes in biocatalysis. In many instances, the main reason for their use is their high specificity or selectivity. However, when full modification of a multifunctional and heterogeneous substrate is pursued, enzyme selectivity and specificity become a problem. This is the case of hydrolysis of oils and fats to produce free fatty acids or their alcoholysis to produce biodiesel, which can be considered cascade reactions. In these cases, to the original heterogeneity of the substrate, the presence of intermediate products, such as diglycerides or monoglycerides, can be an additional drawback. Using these heterogeneous substrates, enzyme specificity can promote that some substrates (initial substrates or intermediate products) may not be recognized as such (in the worst case scenario they may be acting as inhibitors) by the enzyme, causing yields and reaction rates to drop. To solve this situation, a mixture of lipases with different specificity, selectivity and differently affected by the reaction conditions can offer much better results than the use of a single lipase exhibiting a very high initial activity or even the best global reaction course. This mixture of lipases from different sources has been called “combilipases” and is becoming increasingly popular. They include the use of liquid lipase formulations or immobilized lipases. In some instances, the lipases have been coimmobilized. Some discussion is offered regarding the problems that this coimmobilization may give rise to, and some strategies to solve some of these problems are proposed. The use of combilipases in the future may be extended to other processes and enzymes.

Comparative studies of endocannabinoid modulation of pain

Cannabinoid-based therapies have long been used to treat pain, but there remain questions about their actual mechanisms and efficacy. From an evolutionary perspective, the cannabinoid system would appear to be highly conserved given that the most prevalent endogenous cannabinoid (endocannabinoid) transmitters, 2-arachidonyl glycerol and anandamide, have been found throughout the animal kingdom, at least in the species that have been analysed to date. This review will first examine recent findings regarding the potential conservation across invertebrates and chordates of the enzymes responsible for endocannabinoid synthesis and degradation and the receptors that these transmitters act on. Next, comparisons of how endocannabinoids modulate nociception will be examined for commonalities between vertebrates and invertebrates, with a focus on the medicinal leech Hirudo verbana. Evidence is presented that there are distinct, evolutionarily conserved anti-nociceptive and pro-nociceptive effects. The combined studies across various animal phyla demonstrate the utility of using comparative approaches to understand conserved mechanisms for modulating nociception. This article is part of the Theo Murphy meeting issue 'Evolution of mechanisms and behaviour important for pain'.

Synthetic Biology to Improve the Production of Lipases and Esterases (Review)

Synthetic biology is an emergent field of research whose aim is to make biology an engineering discipline, thus permitting to design, control, and standardize biological processes. Synthetic biology is therefore expected to boost the development of biotechnological processes such as protein production and enzyme engineering, which can be significantly relevant for lipases and esterases.

Role of N-Arachidonoyl-Serotonin (AA-5-HT) in Sleep-Wake Cycle Architecture, Sleep Homeostasis, and Neurotransmitters Regulation

The endocannabinoid system comprises several molecular entities such as endogenous ligands [anandamide (AEA) and 2-arachidonoylglycerol (2-AG)], receptors (CB₁ and CB₂), enzymes such as [fatty acid amide hydrolase (FAHH) and monoacylglycerol lipase (MAGL)], as well as the anandamide membrane transporter. Although the role of this complex neurobiological system in the sleep–wake cycle modulation has been studied, the contribution of the blocker of FAAH/transient receptor potential cation channel subfamily V member 1 (TRPV1), N-arachidonoyl-serotonin (AA-5-HT) in sleep has not been investigated. Thus, in the present study, varying doses of AA-5-HT (5, 10, or 20 mg/Kg, i.p.) injected at the beginning of the lights-on period of rats, caused no statistical changes in sleep patterns. However, similar pharmacological treatment given to animals at the beginning of the dark period decreased wakefulness (W) and increased slow wave sleep (SWS) as well as rapid eye movement sleep (REMS). Power spectra analysis of states of vigilance showed that injection of AA-5-HT during the lights-off period diminished alpha spectrum across alertness in a dose-dependent fashion. In opposition, delta power spectra was enhanced as well as theta spectrum, during SWS and REMS, respectively. Moreover, the highest dose of AA-5-HT decreased wake-related contents of neurotransmitters such as dopamine (DA), norepinephrine (NE), epinephrine (EP), serotonin (5-HT) whereas the levels of adenosine (AD) were enhanced. In addition, the sleep-inducing properties of AA-5-HT were confirmed since this compound blocked the increase in W caused by stimulants such as cannabidiol (CBD) or modafinil (MOD) during the lights-on period. Additionally, administration of AA-5-HT also prevented the enhancement in contents of DA, NE, EP, 5-HT and AD after CBD of MOD injection. Lastly, the role of AA-5-HT in sleep homeostasis was tested in animals that received either CBD or MOD after total sleep deprivation (TSD). The injection of CBD or MOD increased alertness during sleep rebound period after TSD. However, AA-5-HT blocked this effect by allowing animals to display an enhancement in sleep across sleep rebound period. Overall, our findings provide evidence that AA-5-HT is an important modulator of sleep, sleep homeostasis and neurotransmitter contents.

Role of the endocannabinoid system in vertebrates: Emphasis on the zebrafish model

The endocannabinoid system (eCBs), named after the plant Cannabis sativa, comprises cannabinoid receptors, endogenous ligands known as "endocannabinoids", and enzymes involved in the biosynthesis and degradation of these ligands, as well as putative transporters for these ligands. ECBs proteins and small molecules have been detected in early embryonic stages of many vertebrate models. As a result, cannabinoid receptors and endogenous as well as exogenous cannabinoids influence development and behavior in many vertebrate species. Understanding the precise mechanisms of action for the eCBs will provide an invaluable guide towards elucidation of vertebrate development and will also help delineate how developmental exposure to marijuana might impact health and cognitive/executive functioning in adulthood. Here we review the developmental roles of the eCBs in vertebrates, focusing our attention on the zebrafish model. Since little is known regarding the eCBs in zebrafish, we provide new data on the expression profiles of eCBs genes during development and in adult tissue types of this model organism. We also highlight exciting areas for future investigations, including the synaptic regulation of eCBs, its role in reward and addiction, and in nervous system development and plasticity.

Rice Bran and Probiotics Alter the Porcine Large Intestine and Serum Metabolomes for Protection against Human Rotavirus Diarrhea

Human rotavirus (HRV) is a leading cause of severe childhood diarrhea, and there is limited vaccine efficacy in the developing world. Neonatal gnotobiotic pigs consuming a prophylactic synbiotic combination of probiotics and rice bran (Pro+RB) did not exhibit HRV diarrhea after challenge. Multiple immune, gut barrier protective, and anti-diarrheal mechanisms contributed to the prophylactic efficacy of Pro+RB when compared to probiotics (Pro) alone. In order to understand the molecular signature associated with diarrheal protection by Pro+RB, a global non-targeted metabolomics approach was applied to investigate the large intestinal contents and serum of neonatal gnotobiotic pigs. The ultra-high performance liquid chromatography-tandem mass spectrometry platform revealed significantly different metabolites (293 in LIC and 84 in serum) in the pigs fed Pro+RB compared to Pro, and many of these metabolites were lipids and amino acid/peptides. Lipid metabolites included 2-oleoylglycerol (increased 293.40-fold in LIC of Pro+RB, p = 3.04E-10), which can modulate gastric emptying, andhyodeoxycholate (decreased 0.054-fold in the LIC of Pro+RB, p = 0.0040) that can increase colonic mucus production to improve intestinal barrier function. Amino acid metabolites included cysteine (decreased 0.40-fold in LIC, p = 0.033, and 0.62-fold in serum, p = 0.014 of Pro+RB), which has been found to reduce inflammation, lower oxidative stress and modulate mucosal immunity, and histamine (decreased 0.18-fold in LIC, p = 0.00030, of Pro+RB and 1.57-fold in serum, p = 0.043), which modulates local and systemic inflammatory responses as well as influences the enteric nervous system. Alterations to entire LIC and serum metabolic pathways further contributed to the anti-diarrheal and anti-viral activities of Pro+RB such as sphingolipid, mono/diacylglycerol, fatty acid, secondary bile acid, and polyamine metabolism. Sphingolipid and long chain fatty acid profiles influenced the ability of HRV to both infect and replicate within cells, suggesting that Pro+RB created a protective lipid profile that interferes with HRV activity. Polyamines act on enterocyte calcium-sensing receptors to modulate intracellular calcium levels, and may directly interfere with rotavirus replication. These results support that multiple host and probiotic metabolic networks, notably those involving lipid and amino acid/peptide metabolism, are important mechanisms through which Pro+RB protected against HRV diarrhea in neonatal gnotobiotic pigs.