Novel probiotic preparation with in vivo gluten-degrading activity and potential modulatory effects on the gut microbiota

Gluten possesses unique properties that render it only partially digestible. Consequently, it exerts detrimental effects on a part of the worldwide population who are afflicted with celiac disease (1%) or related disorders (5%), particularly due to the potential for cross-contamination even when adhering to a gluten-free diet (GFD). Finding solutions to break down gluten during digestion has a high nutritional and social impact. Here, a randomized double-blind placebo-controlled in vivo challenge investigated the gluten-degrading activity of a novel probiotic preparation comprising lactobacilli and their cytoplasmic extracts, Bacillus sp., and bacterial protease. In our clinical trial, we collected feces from 70 healthy volunteers at specific time intervals. Probiotic/placebo administration lasted 32 days, followed by 10 days of wash-out. After preliminary GFD to eliminate residual gluten from feces, increasing amounts of gluten (50 mg-10 g) were administered, each one for 4 consecutive days. Compared to placebo, the feces of volunteers fed with probiotics showed much lower amounts of residual gluten, mainly with increased intakes. Probiotics also regulate the intestinal microbial communities, improving the abundance of genera pivotal to maintaining homeostasis. Quantitative PCR confirmed that all probiotics persisted during the intervention, some also during wash-out. Probiotics promoted a fecal metabolome with potential immunomodulating activity, mainly related to derivatives of branched-chain amino acids and short-chain fatty acids.

IMPORTANCE

The untapped potential of gluten-degrading bacteria and their application in addressing the recognized limitations of gluten-related disorder management and the ongoing risk of cross-contamination even when people follow a gluten-free diet (GFD) emphasizes the significance of the work. Because gluten, a common protein found in many cereals, must be strictly avoided to stop autoimmune reactions and related health problems, celiac disease and gluten sensitivity present difficult hurdles. However, because of the hidden presence of gluten in many food products and the constant danger of cross-contamination during food preparation and processing, total avoidance is frequently challenging. Our study presents a novel probiotic preparation suitable for people suffering from gluten-related disorders during GFD and for healthy individuals because it enhances gluten digestion and promotes gut microbiota functionality.

Prokaryotic diversity of tropical coastal sand dunes ecosystem using metagenomics

Coastal sand dunes (CSDs), unique, stressed and hostile habitats act as a barrier between marine and terrestrial ecosystems. CSDs are stressed in terms of nutrition and fluctuating physio-chemical conditions. CSD is classified into several types, each of which presents different challenges for life forms. This study focuses on exploring bacterial and archaeal diversity and community structure in four CSD namely, Embryo, Fore, Gray, and Mature dunes of Keri beach, Goa along the west coast of India. The study was carried out using Next Generation Sequencing of hypervariable V3-V4 regions of the 16S rRNA gene using Illumina HiSeq platform. The present study hypothesizes that the prokaryotic communities at each dune may be different and could have different role in the ecosystem. The NGS for Embryo, Fore, Gray, and Mature dunes gave 1,045,447, 1,451,753, 1,321,867, and 1,537,758 paired-end reads, respectively, out of which 54,500, 50,032, 37,819, and 111,186 were retained through various quality filtrations. A total of 74, 63, 65, and 65% of OTUs, respectively, remained unknown at the species level. The highest bacterial and archaeal abundance was reported from Mature and Embryo dunes, respectively. Phylum Actinobacteria dominated the Embryo, Fore, and Mature dunes, whereas phylum Proteobacteria was the dominant in the Gray dune. Streptomyces was predominant in overall CSD followed by Bacillus, Acidobacterium, and Kouleothrix. The commonly and exclusively found members in each dune are cataloged. The highest species dominance, diversity, species richness, and abundance were observed in Embryo, Fore, Gray, and Mature dunes, respectively. The present study clearly elucidates that each dune has a distinct microbial community structure.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13205-021-02809-5.

Determinación microbiológica y molecular mediante PCR en tiempo real de dos bacterias del género Bacillus de interés agro biotecnológico

Se efectuó la comparación de curvas de crecimiento a diferentes rangos de pH, salinidad y temperatura, además se determinó el tamaño, forma y posición de endospora de dos diferentes cepas del género Bacillus. Para la identificación molecular se realizó la extracción de ácidos nucleicos, utilizando el kit High Pure PCR Template Preparation Kit de Roche® y posteriormente se analizaron las curvas de amplificación producto de la PCR en Tiempo Real. Se realizaron cinéticas de crecimiento a cada uno de los cultivos de bacterias durante 72 horas y se analizaron estadísticamente las curvas mediante los métodos estadísticos ANOVA y Tukey para determinar significancia (p˂0.001). El análisis factorial para la variable “temperatura” no mostró una diferencia significativa entre cepas y tampoco con los valores fijados (28, 32, 37 °C), la variable “pH” si presentó una interacción con valores (p<0.0001) entre cepas; la variable “salinidad” también presentó diferencia significativa entre cepas y con sus respectivas interacciones. En el análisis del área bajo la curva, la variable “temperatura” no mostró diferencia significativa, mientras que las variables “pH y salinidad” presentaron valores correspondientes a (p<0.0001). Para la determinación molecular, se analizaron las curvas de amplificación, confirmando la presunción bioquímica de la cepa BM como B. megaterium mediante el análisis del gen phaC, así como también se pudo corroborar que la cepa BL corresponde a B. licheniformis al analizar el gen lchAA. La cinética bacteriana permitió establecer las horas clave para el análisis del crecimiento, confirmando que las características analizadas corresponden a especies pertenecientes a la familia Bacillaceae, con aplicación como controladores biológicos en la agricultura.

Class IV polyhydroxyalkanoate (PHA) synthases and PHA-producing Bacillus

This review highlights the recent investigations of class IV polyhydroxyalkanoate (PHA) synthases, the newest classification of PHA synthases. Class IV synthases are prevalent in organisms of the Bacillus genus and are composed of a catalytic subunit PhaC (approximately 40 kDa), which has a PhaC box sequence ([GS]-X-C-X-[GA]-G) at the active site, and a second subunit PhaR (approximately 20 kDa). The representative PHA-producing Bacillus strains are Bacillus megaterium and Bacillus cereus; the nucleotide sequence of phaC and the genetic organization of the PHA biosynthesis gene locus are somewhat different between these two strains. It is generally considered that class IV synthases favor short-chain-length monomers such as 3-hydroxybutyrate (C4) and 3-hydroxyvalerate (C5) for polymerization, but can polymerize some unusual monomers as minor components. In Escherichia coli expressing PhaRC from B. cereus YB-4, the biosynthesized PHA undergoes synthase-catalyzed alcoholytic cleavage using endogenous and exogenous alcohols. This alcoholysis is thought to be shared among class IV synthases, and this reaction is useful not only for the regulation of PHA molecular weight but also for the modification of the PHA carboxy terminus. The novel properties of class IV synthases will open up the possibility for the design of new PHA materials.