Amylase Gene Research Articles

The transcription factor CCT30 promotes rice preharvest sprouting by regulating sugar signalling to inhibit the ABA‐mediated pathway

SummarySeed dormancy is an important adaptive trait in plants. Proper seed dormancy enables the avoidance of preharvest sprouting in the undesirable conditions like rainfall frequently. In this study, qPSR8, a major QTL for preharvest sprouting, was isolated, and a previously reported heading‐date gene, CCT30, was verified as the candidate gene. The CCT30 knockout mutants (CCT30‐CR) enhanced seed dormancy and ABA sensitivity as compared with the wild‐type ZH11. Conversely, CCT30 overexpressing plants had opposite phenotype changes and had a decreased ABA content. The expression of ABA synthesis genes such as OsNCEDs and ABA signalling genes such as ABI3 and ABI5 were upregulated and sugar metabolism‐related genes such as amylase genes were downregulated in CCT30‐CR. Correspondingly, fewer free sugars, such as monosaccharides and oligosaccharides, accumulated in CCT30‐CR. The freshly harvested seeds from CCT30‐CR had no ability to transmit sugar signals when treated with 1% exogenous glucose. In addition, CCT30 interacted with the transcription factor OsbZIP37, which negatively regulates seed dormancy. Overall, CCT30 promotes preharvest sprouting by enhancing sugar signals that inhibit the ABA‐mediated pathway, and CCT30 is a good gene for breeding rice varieties resistant to preharvest sprouting.

Reconstruction of the human amylase locus reveals ancient duplications seeding modern-day variation.

Previous studies suggested that the copy number of the human salivary amylase gene, AMY1, correlates with starch-rich diets. However, evolutionary analyses are hampered by the absence of accurate, sequence-resolved haplotype variation maps. We identified 30 structurally distinct haplotypes at nucleotide resolution among 98 present-day humans, revealing that the coding sequences of AMY1 copies are evolving under negative selection. Genomic analyses of these haplotypes in archaic hominins and ancient human genomes suggest that a common three-copy haplotype, dating as far back as 800 KYA, has seeded rapidly evolving rearrangements through recurrent non-allelic homologous recombination. Additionally, haplotypes with more than three AMY1 copies have significantly increased in frequency among European farmers over the past 4,000 years, potentially as an adaptive response to increased starch digestion.

Influence of AMY1 gene copy number on salivary amylase activity changes induced by exercise in young adults.

Human salivary amylase secretion increases in response to stress; the activity has been reported to rise significantly with high-intensity exercise. The human salivary amylase gene (AMY1) has copy number variation, with the copy number correlating with salivary amylase activity. However, the relationship between individual AMY1 copy number and salivary amylase activity in response to exercise remains unclear. In this study, we investigated AMY1 copy number and fluctuations in amylase activity in 42 healthy university students (25 males and 17 females). Participants engaged in intermittent round-trip interval training on a basketball court. Saliva samples were collected pre- and post-exercise to measure amylase activity. DNA was extracted from the oral mucosa, and AMY1 copy number was quantified using RT-PCR. Results showed a significant increase in amylase activity postexercise. Additionally, amylase activity pre- and post-exercise was positively correlated with AMY1 copy number. The generalize linear model showed that the exercise-induced increase in amylase activity per AMY1 gene was negatively related to the AMY1 copy number and aerobic fitness. Gender has no effect on amylase activity. These results suggest a different mechanism for the constitutive and exercise-induced amylase secretion, while aerobic fitness may be independently involved in the secretion.

Mutual regulation of novel transcription factors RsrD and RsrE positively modulates the production of raw-starch-degrading enzyme in Penicillium oxalicum.

Filamentous fungi can produce raw-starch-degrading enzyme, however, regulation of production of raw-starch-degrading enzyme remains poorly understood thus far. Here, two novel transcription factors raw-starch-degrading enzyme regulator D (RsrD) and raw-starch-degrading enzyme regulator E (RsrE) were identified to participate in the production of raw-starch-degrading enzyme in Penicillium oxalicum. Individual knockout of rsrD and rsrE in the parental strain Δku70 resulted in 31.1%-92.9% reduced activity of raw-starch-degrading enzyme when cultivated in the presence of commercial starch from corn. RsrD and RsrE contained a basic leucine zipper and a Zn2Cys6-type DNA-binding domain, respectively, but with unknown functions. RsrD and RsrE dynamically regulated the expression of genes encoding major amylases over time, including raw-starch-degrading glucoamylase gene PoxGA15A and α-amylase gene amy13A. Interestingly, RsrD and RsrE regulated each other at transcriptional level, through binding to their own promoter regions; nevertheless, both failed to bind to the promoter regions of PoxGA15A and amy13A, as well as the known regulatory genes for regulation of amylase gene expression. RsrD appears to play an epistatic role in the module RsrD-RsrE on regulation of amylase gene expression. This study reveals a novel regulatory pathway of fungal production of raw-starch-degrading enzyme.IMPORTANCETo survive via combating with complex extracellular environment, filamentous fungi can secrete plant polysaccharide-degrading enzymes that can efficiently hydrolyze plant polysaccharide into glucose or other mono- and disaccharides, for their nutrients. Among the plant polysaccharide-degrading enzymes, raw-starch-degrading enzymes directly degrade and convert hetero-polymeric starch into glucose and oligosaccharides below starch gelatinization temperature, which can be applied in industrial biorefinery to save cost. However, the regulatory mechanism of production of raw-starch-degrading enzyme in fungi remains unknown thus far. Here, we showed that two novel transcription factors raw-starch-degrading enzyme regulator D (RsrD) and raw-starch-degrading enzyme regulator E (RsrE) positively regulate the production of raw-starch-degrading enzyme by Penicillium oxalicum. RsrD and RsrE indirectly control the expression of genes encoding enzymes with amylase activity but directly regulate each other at transcriptional level. These findings expand diversity of gene expression regulation in fungi.

A RsrC-RsrA-RsrB transcriptional circuit positively regulates polysaccharide-degrading enzyme biosynthesis and development in Penicillium oxalicum

Filamentous fungi produce polysaccharide-degrading enzymes, which is controlled by poorly understood transcriptional circuits. Here we show that a circuit comprising RsrC-RsrA-RsrB (Rsr: production of raw-starch-degrading enzyme regulator) that positively regulates production of raw starch-degrading enzymes in Penicillium oxalicum. Transcription factor (TF) RsrA is essential for biosynthesis of raw starch-degrading enzymes. RsrB and RsrC containing Zn2Cys6- and C2H2-zinc finger domains, act downstream and upstream of RsrA, respectively. RsrA activates rsrB transcription, and three nucleotides (G-286, G-287 and G-292) of rsrB promoter region are required for RsrA, in terms of TF, for binding. RsrB165−271 binds to DNA sequence 5’-TCGATCAGGCACGCC-3’ in the promoter region of the gene encoding key raw-starch-degrading enzyme PoxGA15A. RsrC specifically binds rsrA promoter, but not amylase genes, to positively regulate the expression of rsrA and the production of raw starch-degrading enzymes. These findings expand complex regulatory network of fungal raw starch-degrading enzyme biosynthesis.

Upregulation of Amy1 in the salivary glands of mice exposed to a lunar gravity environment using the multiple artificial gravity research system.

Introduction: Space is a unique environment characterized by isolation from community life and exposure to circadian misalignment, microgravity, and space radiation. These multiple differences from those experienced on the earth may cause systemic and local tissue stress. Autonomic nerves, including sympathetic and parasympathetic nerves, regulate functions in multiple organs. Saliva is secreted from the salivary gland, which is regulated by autonomic nerves, and plays several important roles in the oral cavity and digestive processes. The balance of the autonomic nervous system in the seromucous glands, such as the submandibular glands, precisely controls serous and mucous saliva. Psychological stress, radiation damage, and other triggers can cause an imbalance in salivary secretion systems. A previous study reported that amylase is a stress marker in behavioral medicine and space flight crews; however, the detailed mechanisms underlying amylase regulation in the space environment are still unknown. Methods: In this study, we aimed to elucidate how lunar gravity (1/6g) changes mRNA expression patterns in the salivary gland. Using a multiple artificial gravity research system during space flight in the International Space Station, we studied the effects of two different gravitational levels, lunar and Earth gravity, on the submandibular glands of mice. All mice survived, returned to Earth from space, and their submandibular glands were collected 2days after landing. Results: We found that lunar gravity induced the expression of the salivary amylase gene Amy1; however, no increase in Aqp5 and Ano1, which regulate water secretion, was observed. In addition, genes involved in the exocrine system, such as vesicle-associated membrane protein 8 (Vamp8) and small G proteins, including Rap1 and Rab families, were upregulated under lunar gravity. Conclusion: These results imply that lunar gravity upregulates salivary amylase secretion via Rap/Rab signaling and exocytosis via Vamp8. Our study highlights Amy1 as a potential candidate marker for stress regulation in salivary glands in the lunar gravity environment.

Gut microbial features and dietary fiber intake predict gut microbiota response to resistant starch supplementation

ABSTRACT Resistant starch (RS) consumption can have beneficial effects on metabolic health, but the response, in terms of effects on the gut microbiota and host physiology, varies between individuals. Factors predicting the response to RS are not yet established and would be useful for developing precision nutrition approaches that maximize the benefits of dietary fiber intake. We sought to identify predictors of gut microbiota response to RS supplementation. We enrolled 76 healthy adults into a 7-week crossover study with 59 individuals completing the study. Participants consumed RS type 2 (RS2), RS type 4 (RS4), and digestible starch, for 10 d each with 5-d washout periods in between. We collected fecal and saliva samples and food records during each treatment period. We performed 16S rRNA gene sequencing and measured fecal short-chain fatty acids (SCFAs), salivary amylase (AMY1) gene copy number, and salivary amylase activity (SAA). Dietary fiber intake was predictive of the relative abundance of several amplicon sequence variants (ASVs) at the end of both RS treatments. AMY1-related metrics were not predictive of response to RS. SAA was only predictive of the relative abundance of one ASV after digestible starch supplementation. Interestingly, SCFA concentrations increased the most during digestible starch supplementation. Treatment order (the order of consumption of RS2 and RS4), alpha diversity, and a subset of ASVs were predictive of SCFA changes after RS supplementation. Based on our findings, dietary fiber intake and gut microbiome composition would be informative if assessed prior to recommending RS supplementation because these data can be used to predict changes in specific ASVs and fecal SCFA concentrations. These findings lay a foundation to support the premise that using a precision nutrition approach to optimize the benefits of dietary fibers such as RS could be an effective strategy to compensate for the low consumption of dietary fiber nationwide.

Global diversity, recurrent evolution, and recent selection on amylase structural haplotypes in humans.

The adoption of agriculture, first documented ~12,000 years ago in the Fertile Crescent, triggered a rapid shift toward starch-rich diets in human populations. Amylase genes facilitate starch digestion and increased salivary amylase copy number has been observed in some modern human populations with high starch intake, though evidence of recent selection is lacking. Here, using 52 long-read diploid assemblies and short read data from ~5,600 contemporary and ancient humans, we resolve the diversity, evolutionary history, and selective impact of structural variation at the amylase locus. We find that amylase genes have higher copy numbers in populations with agricultural subsistence compared to fishing, hunting, and pastoral groups. We identify 28 distinct amylase structural architectures and demonstrate that nearly identical structures have arisen recurrently on different haplotype backgrounds throughout recent human history. AMY1 and AMY2A genes each exhibit multiple duplications/deletions with mutation rates >10,000-fold the SNP mutation rate, whereas AMY2B gene duplications share a single origin. Using a pangenome graph-based approach to infer structural haplotypes across thousands of humans, we identify extensively duplicated haplotypes present at higher frequencies in modern day populations with traditionally agricultural diets. Leveraging 533 ancient human genomes we find that duplication-containing haplotypes (i.e. haplotypes with more amylase gene copies than the ancestral haplotype) have increased in frequency more than seven-fold over the last 12,000 years providing evidence for recent selection in West Eurasians. Together, our study highlights the potential impacts of the agricultural revolution on human genomes and the importance of long-read sequencing in identifying signatures of selection at structurally complex loci.

Comparative Transcriptomic Analysis Revealing the Potential Mechanisms of Erythritol-Caused Mortality and Oviposition Inhibition in Drosophila melanogaster.

Erythritol has shown excellent insecticidal performance against a wide range of insect species, but the molecular mechanism by which it causes insect mortality and sterility is not fully understood. The mortality and sterility of Drosophila melanogaster were assessed after feeding with 1M erythritol for 72 h and 96 h, and gene expression profiles were further compared through RNA sequencing. Enrichment analysis of GO and KEGG revealed that expressions of the adipokinetic hormone gene (Akh), amylase gene (Amyrel), α-glucosidase gene (Mal-B1/2, Mal-A1-4, Mal-A7/8), and triglyceride lipase gene (Bmm) were significantly up-regulated, while insulin-like peptide genes (Dilp2, Dilp3 and Dilp5) were dramatically down-regulated. Seventeen genes associated with eggshell assembly, including Dec-1 (down 315-fold), Vm26Ab (down 2014-fold) and Vm34Ca (down 6034-fold), were significantly down-regulated or even showed no expression. However, there were no significant differences in the expression of three diuretic hormone genes (DH44, DH31, CAPA) and eight aquaporin genes (Drip, Big brain, AQP, Eglp1, Eglp2, Eglp3, Eglp4 and Prip) involved in osmolality regulation (all p value > 0.05). We concluded that erythritol, a competitive inhibitor of α-glucosidase, severely reduced substrates and enzyme binding, inhibiting effective carbohydrate hydrolysis in the midgut and eventually causing death due to energy deprivation. It was clear that Drosophila melanogaster did not die from the osmolality of the hemolymph. Our findings elucidate the molecular mechanism underlying the mortality and sterility in Drosophila melanogaster induced by erythritol feeding. It also provides an important theoretical basis for the application of erythritol as an environmentally friendly pesticide.

The role of Trichoderma koningii and Trichoderma harzianum in mitigating the combined stresses motivated by Sclerotiniasclerotiorum and salinity in common bean (Phaseolusvulgaris)

Under natural conditions, crops typically suffer from severe challenges due to the increasing of abiotic and biotic stresses which severely affect plant growth and reduc crop yield. The present study investigated the single and combined impacts of Sclerotinia sclerotiorum and salinity stress on common bean (Phaseolus vulgaris L.) seedling which is scarcely studied. The study evaluated the in vitro and in vivo influence of two salinity tolerant Trichoderma isolates, T. koningii and T. harzianum against S. sclerotiorum under salinity stress. The results showed the ability of T. koningii and T. harzianum to grow and sporulate at high levels of salinity, 80 mM NaCl, without significantly impacting their ability to produce cell wall degrading enzymes, cellulase and chitinase. Amylase and proteinase (Prb1) genes were detected in T. harzianum. The in vitro assay revealed that both isolates could inhibit the growth of S. sclerotiorum under high salinity concentrations. In a greenhouse experiment, both Trichoderma isolates ameliorated the damaging impacts of S. sclerotiorum under salinity stress on common bean seedlings' germination and growth characteristics compared to their untreated control. Both bioagents significantly attenuated the damping-off and collar/stem rot percentages of infected common bean under salinity stress. Salinity stress intensified the effect of S. sclerotiorum on photosynthetic pigments, induced oxidative and nitrative stress, hampered ionic homeostasis, and deactivated antioxidants and defense-related molecules. On the other hand, Trichoderma isolates restrained the reduction of chlorophylls and carotenoids, ascorbate, reduced glutathione, flavonoids, phenolics, and various antioxidant enzymes, especially for single stresses and T. harzianum. All these upregulations reflected in keeping the cell membranes of common beans seedling more stable where the levels of lipid peroxidation and methylglyoxal due to the reduction of reactive oxygen species and upregulation of nitric oxide, which expressed better growth under pathogen attack or/and saline. The tested isolates, T. koningii and T. harzianum could be used as effective biological control against S. sclerotiorum on common beans in saline soils or areas irrigated with saline water.

Dynamics of soil microbial communities involved in carbon cycling along three successional forests in southern China.

Dynamics of plant communities during forest succession have been received great attention in the past decades, yet information about soil microbial communities that are involved in carbon cycling remains limited. Here we investigated soil microbial community composition and carbohydrate degradation potential using metagenomic analysis and examined their influencing factors in three successional subtropical forests in southern China. Results showed that the abundances of soil bacteria and fungi increased (p ≤ 0.05 for both) with forest succession in relation to both soil and litter characteristics, whereas the bacterial diversity did not change (p > 0.05) and the fungal diversity of Shannon-Wiener index even decreased (p ≤ 0.05). The abundances of microbial carbohydrate degradation functional genes of cellulase, hemicellulase, and pectinase also increased with forest succession (p ≤ 0.05 for all). However, the chitinase gene abundance did not change with forest succession (p > 0.05) and the amylase gene abundance decreased firstly in middle-succession forest and then increased in late-succession forest. Further analysis indicated that changes of functional gene abundance in cellulase, hemicellulase, and pectinase were primarily affected by soil organic carbon, soil total nitrogen, and soil moisture, whereas the variation of amylase gene abundance was well explained by soil phosphorus and litterfall. Overall, we created a metagenome profile of soil microbes in subtropical forest succession and fostered our understanding of microbially-mediated soil carbon cycling.

Cloning an RBD-T4-LINKER-C5a sequence encoding the SARS-CoV-2 antigen into a plant expression vector

This study aims to make a plant expression vector with an RBD-T4-Linker-C5a sequence that codes for the SARS-CoV-2 antigen and an A3Dsp signal peptide from the rice 3D amylase gene located before the RBD. Methods of molecular cloning were applied in this study. The plant expression vector pNHL22 harboring the RBD-T4-Linker-C5a sequence was successfully established and conjugated into Agrobacterium tumefaciens LBA4404 by triparental mating. Bacteria A. tumefaciens containing the RBD-T4-Linker-C5a sequence are now ready for genetic transformation into the Nicotiana benthamiana plant for future applications.

Insect α-Amylases and Their Application in Pest Management.

Amylase is an indispensable hydrolase in insect growth and development. Its varied enzymatic parameters cause insects to have strong stress resistance. Amylase gene replication is a very common phenomenon in insects, and different copies of amylase genes enable changes in its location and function. In addition, the classification, structure, and interaction between insect amylase inhibitors and amylases have also invoked the attention of researchers. Some plant-derived amylase inhibitors have inhibitory activities against insect amylases and even mammalian amylases. In recent years, an increasing number of studies have clarified the effects of pesticides on the amylase activity of target and non-target pests, which provides a theoretical basis for exploring safe and efficient pesticides, while the exact lethal mechanisms and safety in field applications remain unclear. Here, we summarize the most recent advances in insect amylase studies, including its sequence and characteristics and the regulation of amylase inhibitors (α-AIs). Importantly, the application of amylases as the nanocide trigger, RNAi, or other kinds of pesticide targets will be discussed. A comprehensive foundation will be provided for applying insect amylases to the development of new-generation insect management tools and improving the specificity, stability, and safety of pesticides.

Dietary sodium benzoate improves growth, morphology, antioxidant capacity and resistance against Aeromonas hydrophila of Pacific white shrimp (Litopenaeus vannamei)

Acidifier has become one of the most important substitutes for antibiotics, and its beneficial effects on growth performance and digestive ability have been evidenced. Sodium benzoate is a commonly used acidifier. A 56-day feeding test was carried out to elucidate the effects of dietary sodium benzoate on growth performance, morphology, antioxidant activity and intestinal microflora of juvenile Litopenaeus vannamei with an average initial body weight of 0.55 ± 0.01 g. Six experimental diets were prepared by adding 0, 750, 1000, 1250, 1500 and 1750 mg/kg sodium benzoate to the control diet. The results showed that: The final body weight (FBW) and weight gain (WG) of juvenile shrimp were significantly improved by diet supplemented with 1750 mg/kg sodium benzoate. Dietary 1750 mg/kg sodium benzoate significantly increased the trypsin activity. The activities of catalase (CAT), superoxide dismutase (SOD) and glutathione S-transferase (GST) in the intestine and hepatopancreas of the 1750 mg/kg sodium benzoate group were markedly higher than those of the control group. Furthermore, the expression levels of trypsin (TRY), amylase (AMS), lysozyme (LZM), interleukin-8 (IL8) and interleukin-10 (IL10) genes in the intestine significantly increased when the content of sodium benzoate in the diet was greater than or equal to 1000 mg/kg. The addition of 1500 and 1750 mg/kg sodium benzoate to the feed improved the intestinal and hepatopancreatic tissue structures of juvenile shrimp and enriched the diversity of intestinal microbiota. Sodium benzoate residues were not detected in each sodium benzoate supplemented group. At the end of the Aeromonas hydrophila challenge test, juvenile shrimp in the 1500 and 1750 mg/kg group exhibited significantly higher cumulative survival rates than that in the control group. Conclusively, dietary 1750 mg/kg sodium benzoate could improve the growth performance, antioxidant capacity, morphology, intestinal microflora and disease resistance of juvenile shrimp.

GeneToCN: an alignment-free method for gene copy number estimation directly from next-generation sequencing reads

Genomes exhibit large regions with segmental copy number variation, many of which include entire genes and are multiallelic. We have developed a computational method GeneToCN that counts the frequencies of gene-specific k-mers in FASTQ files and uses this information to infer copy number of the gene. We validated the copy number predictions for amylase genes (AMY1, AMY2A, AMY2B) using experimental data from digital droplet PCR (ddPCR) on 39 individuals and observed a strong correlation (R = 0.99) between GeneToCN predictions and experimentally determined copy numbers. An additional validation on FCGR3 genes showed a higher concordance for FCGR3A compared to two other methods, but reduced accuracy for FCGR3B. We further tested the method on three different genomic regions (SMN, NPY4R, and LPA Kringle IV-2 domain). Predicted copy number distributions of these genes in a set of 500 individuals from the Estonian Biobank were in good agreement with the previously published studies. In addition, we investigated the possibility to use GeneToCN on sequencing data generated by different technologies by comparing copy number predictions from Illumina, PacBio, and Oxford Nanopore data of the same sample. Despite the differences in variability of k-mer frequencies, all three sequencing technologies give similar predictions with GeneToCN.

De novo whole transcriptome analysis of Aeromonas hydrophila isolated from the gut of an infected Labeo rohita.

Aeromonas hydrophila is a major generalist bacterial pathogen causing severe infections and mortalities in aquatic animals. Its genome, which was the first to be sequenced from the Aeromonas genus, may serve as a model for studying pathogenic mechanisms. To explore the pathogen-host fitness mechanism of bacterium, a comprehensive comparative transcriptome ecotype analysis of A. hydrophila isolated from the gut of Labeo rohita during infection was performed. Special characteristics in gene expression, gene ontology terms and expression of pathogenesis-associated genes, including genes encoding secreted proteins, candidate effectors, hydrolases, and proteins involved in secondary metabolite production were revealed. Among the database, 6,533 were gene ontology (GO) annotated, while 1,480 were not allocated in any GO terms. Investigation on GO illustrated that the articulated genes were improved with molecular function, cellular components, and biological processes. Further bioinformatics analysis identified the outer membrane protein genes (ompA, ompts, ompw, omp38, and omp48), cytotoxin, amylase, and lipase genes. Overall, this work allowed to designate, for the first time, a global view on the pathogenicity of Aeromonas hydrophila during infection. Furthermore, the study provides information on the fitness of A. hydrophila, a severe pathogen with a wide host range.

Effect of Aerobic Exercise in Chinese Adult Individuals at Risk for Type 2 Diabetes Mellitus (T2DM) with Low Salivary Amylase Gene (AMY1) Copy Number Variation.

Type 2 Diabetes mellitus (T2DM) has become a life-threatening health problem around the world. Studies have confirmed that aerobic exercise can prevent the risk of T2DM. Furthermore, recent research showed that salivary amylase gene (AMY1) copy number variation (CNV) could be one of the genetic factors that increased the risk of T2DM. To provide more evidence on how AMY1 CNV and exercise is correlated with the risk of T2DM, we designed this study to show the differences in postprandial carbohydrate metabolism between people with different AMY1 copy numbers, and how aerobic exercise can influence this process. Sixteen participants without cardiovascular disease were chosen, 8 with AMY1 CNV≥6 (High CNV group, HCNV), and 8 with AMY1 CNV ≤ 2 (Low CNV group, LCNV). All participants were Chinese, Han nationality, 18 to 40 years old, with fasting blood glucose lower than 6.1 mmol/L and normal blood pressure levels. They were asked to visit the laboratory in fasting state and drink a cup of solution with 75 grams of edible carbohydrate (glucose or starch). After carbohydrate intake, blood samples were taken at certain times at rest or after aerobic exercise. Blood glucose levels were tested with a portable blood glucose monitor, and insulin levels were tested with the enzyme-linked immunosorbent assay (ELISA). The LCNV group had significantly higher resting insulin levels and homeostatic model assessment of insulin resistance (HOMA-IR) than the HCNV group. Compared to the HCNV group, postprandial blood glucose levels and insulin levels were insensitive to starch intake in the LCNV group. However, this difference disappeared after aerobic exercise was added as an intervention. Lower AMY1 CNV could be associated with higher risk of T2DM and complex carbohydrate metabolism disorder, while aerobic exercise can reduce the risk by increasing the carbohydrate utilization rate.

Enhancing Protease and Amylase Activities in Bacillus licheniformis XS-4 for Traditional Soy Sauce Fermentation Using ARTP Mutagenesis.

This study was conducted to increase the enzymatic activity of Bacillus licheniformis XS-4, which was isolated from the traditional fermented mash of Xianshi soy sauce. The mutation was induced by atmospheric and room-temperature plasma (ARTP), and a mutant strain, mut80, was obtained. mut80 exhibited significant increases in protease and amylase activity by 90.54% and 143.10%, respectively, and the enhanced enzymatic activities were stably maintained after 20 consecutive incubations. Re-sequencing analysis of mut80 revealed that the mutation sites were located in 1518447(AT-T) and 4253106(G-A) in its genome, which was involved in the metabolic pathways of amino acids. The expression of the protease synthetic gene (aprX) increased 1.54 times, while that of the amylase gene (amyA) increased 11.26 times, as confirmed via RT-qPCR. Using ARTP mutagenesis, the present study proposes a highly efficient microbial resource with enhanced protease and amylase activity provided by B. licheniformis, which can potentially be used to improve the efficiency of traditional soy sauce fermentation.

Phosducin-like protein PoPlp1 impacts cellulase and amylase expression and development in Penicillium oxalicum via the G protein-cAMP signaling pathway.

In this study, a phosducin-like protein, PoPlp1, was identified and functionally studied in the cellulase-producing strain Penicillium oxalicum 114-2. PoPlp1 was proven to participate in several biological processes, including mycelium development, conidiation, and expression of cellulases and amylases. With deletion of Poplp1, morphology and development varied significantly in ΔPoplp1. Colony growth, glucose utilization, and the hydrolysis capability of starch and cellulose were limited, whereas conidiation was enhanced. Based on detection of the levels of expression of transcription factors involved in asexual development, we conjectured that PoPlp1 is involved in conidiation via the major factor BrlA. We explored the effect of PoPlp1 on cellulase and amylase expression and observed that cellulase and amylase activity and major gene transcription levels were all dramatically reduced in ΔPoplp1. Deletion of PoPlp1 caused a decrease in intracellular cAMP levels, and the cellulase gene expression level of ΔPoplp1 was restored to a certain extent through external addition of cAMP. These findings demonstrate that PoPlp1 may affect cellulase and amylase expression by regulating cAMP concentration. To comprehensively explore the mechanism of PoPlp1 in regulating multiple biological processes, we performed a comparative transcriptomic analysis between strains P. oxalicum 114-2 and ΔPoplp1. The major cellulase and amylase genes were all downregulated, congrent with the results of real-time quantitative polymerase chain reaction analysis. The genes involved in the G protein-cAMP signaling pathway, including several G-protein-coupled receptors, one regulator of G protein signaling, and two cAMP phosphodiesterases, were disrupted by deletion of PoPlp1. These results confirm the positive function of PoPlp1 in the G protein-cAMP signaling pathway. This functional analysis of PoPlp1 will be very beneficial for further study of the regulatory mechanisms of cellulase expression and other biological processes in P. oxalicum 114-2 via the G protein-cAMP signaling pathway.

Salivary amylase gene (AMY1) copy number variation has only a minor correlation with body composition in Chinese adults.

According to the WHO, about 39% of the global adult population were overweight or obese in 2016. Obesity has high heritability, with more than 1000 variants so far identified. There have been reports indicating that salivary amylase gene (AMY1) copy number was one of these variants, yet its association with obesity remains controversial. Our research aimed to provide more evidence on the relationship of AMY1 copy number variation (CNV) with body mass index (BMI) and body composition. We recruited 133 Chinese adults (65 males, 68 females, 18-25years old) with normal fasting blood glucose and blood pressure levels. 19 males were selected for a 10-week intervention to change body composition. After anthropometric measurements, BMI was calculated, and body composition was measured using dual energy X-ray absorptiometry (DEXA). For the 19 selected participants, we collected their height, weight, and body composition data one more time after intervention. All participants were required to leave their saliva samples and their AMY1 copy number was determined by real-time fluorescence quantitative PCR. We failed to find any significant difference in BMI and body composition between different copy number groups. Only a weak correlation was found between body muscle mass and body fat mass. After adjusted for height and weight, AMY1 CNV explained 4.83% of the variance and one single increase in AMY1 CNV can increase 0.214kg of the body muscle mass, while one single increase in AMY1 CNV can decrease 0.217kg of the body fat mass and explained 4.69% of the variance. As a genetic factor, the AMY1 gene copy number variation has only a minor correlation with BMI and body composition, and its effect can easily be hidden by other factors such as individual diet and exercise habit.