scholarly journals Growth and autolysis of the kefir yeast Kluyveromyces marxianus in lactate culture

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shou-Chen Lo ◽  
Chia-Yin Yang ◽  
Dony Chacko Mathew ◽  
Chieh-Chen Huang

AbstractKluyveromyces marxianus is a yeast that could be identified from kefir and can use a broad range of substrates, such as glucose and lactate, as carbon sources. The lactate produced in kefir culture can be a substrate for K. marxianus. However, the complexity of the kefir microbiota makes the traits of K. marxianus difficult to study. In this research, we focused on K. marxianus cultured with lactate as the sole carbon source. The optimal growth and released protein in lactate culture were determined under different pH conditions, and the LC–MS/MS-identified proteins were associated with the tricarboxylic acid cycle, glycolysis pathway, and cellular stress responses in cells, indicating that autolysis of K. marxianus had occurred under the culture conditions. The abundant glyceraldehyde-3-phosphate dehydrogenase 1 (GAP1) was cocrystallized with other proteins in the cell-free fraction, and the low transcription level of the GAP1 gene indicated that the protein abundance under autolysis conditions was dependent on protein stability. These results suggest that lactate induces the growth and autolysis of K. marxianus, releasing proteins and peptides. These findings can be fundamental for K. marxianus probiotic and kefir studies in the future.

2021 ◽  
Author(s):  
Shou-Chen Lo ◽  
Chia-Yin Yang ◽  
Dony Mathew ◽  
Chieh-Chen Huang

Abstract Kluyveromyces marxianus is a yeast that was identified from kefir and can use a broad range of substrates, such as glucose and lactate, as carbon sources. The lactate produced in kefir culture can be a substrate for K. marxianus. However, the complexity of the kefir microbiota makes the traits of K. marxianus difficult to study. In this research, we focused on K. marxianus cultured with lactate as the sole carbon source. The optimal growth and released protein in lactate culture were determined under different pH conditions, and the LC-MS/MS-identified proteins were associated with the tricarboxylic acid cycle, glycolysis pathway, and cellular stress responses in cells, indicating that autolysis of K. marxianus had occurred under the culture conditions. The abundant glyceraldehyde-3-phosphate dehydrogenase (GAP1) was crystallized in the cell-free fraction, and the low transcription level of the GAP1 gene indicated that the protein abundance under autolysis conditions was dependent on protein stability. These results suggest that lactate produced by lactic acid bacteria stimulates the growth and autolysis of K. marxianus, releasing proteins and peptides. These findings can be fundamental for K. marxianus probiotic and kefir studies in the future.


2004 ◽  
Vol 24 (6) ◽  
pp. 2560-2572 ◽  
Author(s):  
Caroline Dubacq ◽  
Anne Chevalier ◽  
Carl Mann

ABSTRACT The Snf1/AMP-activated kinases are involved in a wide range of stress responses in eukaryotic cells. We discovered a novel role for the Snf1 kinase in the cellular response to genotoxic stress in yeast. snf1 mutants are hypersensitive to hydroxyurea (HU), methyl-methane sulfonate, and cadmium, but they are not sensitive to several other genotoxic agents. HU inhibits ribonucleotide reductase (RNR), and deletion of SNF1 also increased the growth defects of an rnr4 ribonucleotide reductase mutant. The snf1 mutant has a functional checkpoint response to HU insofar as cells arrest division normally and derepress the transcription of RNR genes. The sensitivity of snf1 to HU or to RNR4 deletion may be due to posttranscriptional defects in RNR function or to defects in the repair of, and recovery from, stalled replication forks. The Mig3 repressor was identified as one target of Snf1 in this pathway. Genetic and biochemical analyses suggest that a weak kinase activity is sufficient to confer resistance to HU, whereas a high level of kinase activity is required for optimal growth on carbon sources other than glucose. Quantitative regulation of Snf1 kinase activity may contribute to the specificity of the effector responses that it controls.


Biomedicines ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 99
Author(s):  
Shweta Devi ◽  
Vijay Kumar ◽  
Sandeep Kumar Singh ◽  
Ashish Kant Dubey ◽  
Jong-Joo Kim

Neurodegenerative disorders, such as Parkinson’s disease (PD), Alzheimer’s disease (AD), Amyotrophic lateral sclerosis (ALS), and Huntington’s disease (HD), are the most concerning disorders due to the lack of effective therapy and dramatic rise in affected cases. Although these disorders have diverse clinical manifestations, they all share a common cellular stress response. These cellular stress responses including neuroinflammation, oxidative stress, proteotoxicity, and endoplasmic reticulum (ER)-stress, which combats with stress conditions. Environmental stress/toxicity weakened the cellular stress response which results in cell damage. Small molecules, such as flavonoids, could reduce cellular stress and have gained much attention in recent years. Evidence has shown the potential use of flavonoids in several ways, such as antioxidants, anti-inflammatory, and anti-apoptotic, yet their mechanism is still elusive. This review provides an insight into the potential role of flavonoids against cellular stress response that prevent the pathogenesis of neurodegenerative disorders.


Life ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 304
Author(s):  
Tatyana Savchenko ◽  
Konstantin Tikhonov

Oxidative stress is an integral component of various stress conditions in plants, and this fact largely determines the substantial overlap in physiological and molecular responses to biotic and abiotic environmental challenges. In this review, we discuss the alterations in central metabolism occurring in plants experiencing oxidative stress. To focus on the changes in metabolite profile associated with oxidative stress per se, we primarily analyzed the information generated in the studies based on the exogenous application of agents, inducing oxidative stress, and the analysis of mutants displaying altered oxidative stress response. Despite of the significant variation in oxidative stress responses among different plant species and tissues, the dynamic and transient character of stress-induced changes in metabolites, and the strong dependence of metabolic responses on the intensity of stress, specific characteristic changes in sugars, sugar derivatives, tricarboxylic acid cycle metabolites, and amino acids, associated with adaptation to oxidative stress have been detected. The presented analysis of the available data demonstrates the oxidative stress-induced redistribution of metabolic fluxes targeted at the enhancement of plant stress tolerance through the prevention of ROS accumulation, maintenance of the biosynthesis of indispensable metabolites, and production of protective compounds. This analysis provides a theoretical basis for the selection/generation of plants with improved tolerance to oxidative stress and the development of metabolic markers applicable in research and routine agricultural practice.


2014 ◽  
Vol 64 (Pt_3) ◽  
pp. 781-786 ◽  
Author(s):  
Maximo Sánchez ◽  
Martha-Helena Ramírez-Bahena ◽  
Alvaro Peix ◽  
María J. Lorite ◽  
Juan Sanjuán ◽  
...  

Strain S658T was isolated from a Lotus corniculatus nodule in a soil sample obtained in Uruguay. Phylogenetic analysis of the 16S rRNA gene and atpD gene showed that this strain clustered within the genus Phyllobacterium . The closest related species was, in both cases, Phyllobacterium trifolii PETP02T with 99.8 % sequence similarity in the 16S rRNA gene and 96.1 % in the atpD gene. The 16S rRNA gene contains an insert at the beginning of the sequence that has no similarities with other inserts present in the same gene in described rhizobial species. Ubiquinone Q-10 was the only quinone detected. Strain S658T differed from its closest relatives through its growth in diverse culture conditions and in the assimilation of several carbon sources. It was not able to reproduce nodules in Lotus corniculatus. The results of DNA–DNA hybridization, phenotypic tests and fatty acid analyses confirmed that this strain should be classified as a representative of a novel species of the genus Phyllobacterium , for which the name Phyllobacterium loti sp. nov. is proposed. The type strain is S658T( = LMG 27289T = CECT 8230T).


Antioxidants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1227
Author(s):  
Ali Mahmoud El-Badri ◽  
Maria Batool ◽  
Ibrahim A. A. Mohamed ◽  
Zongkai Wang ◽  
Ahmed Khatab ◽  
...  

Measuring metabolite patterns and antioxidant ability is vital to understanding the physiological and molecular responses of plants under salinity. A morphological analysis of five rapeseed cultivars showed that Yangyou 9 and Zhongshuang 11 were the most salt-tolerant and -sensitive, respectively. In Yangyou 9, the reactive oxygen species (ROS) level and malondialdehyde (MDA) content were minimized by the activation of antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) for scavenging of over-accumulated ROS under salinity stress. Furthermore, Yangyou 9 showed a significantly higher positive correlation with photosynthetic pigments, osmolyte accumulation, and an adjusted Na+/K+ ratio to improve salt tolerance compared to Zhongshuang 11. Out of 332 compounds identified in the metabolic profile, 225 metabolites were filtrated according to p < 0.05, and 47 metabolites responded to salt stress within tolerant and sensitive cultivars during the studied time, whereas 16 and 9 metabolic compounds accumulated during 12 and 24 h, respectively, in Yangyou 9 after being sown in salt treatment, including fatty acids, amino acids, and flavonoids. These metabolites are relevant to metabolic pathways (amino acid, sucrose, flavonoid metabolism, and tricarboxylic acid cycle (TCA), which accumulated as a response to salinity stress. Thus, Yangyou 9, as a tolerant cultivar, showed improved antioxidant enzyme activity and higher metabolite accumulation, which enhances its tolerance against salinity. This work aids in elucidating the essential cellular metabolic changes in response to salt stress in rapeseed cultivars during seed germination. Meanwhile, the identified metabolites can act as biomarkers to characterize plant performance in breeding programs under salt stress. This comprehensive study of the metabolomics and antioxidant activities of Brassica napus L. during the early seedling stage is of great reference value for plant breeders to develop salt-tolerant rapeseed cultivars.


Insects ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 552
Author(s):  
Wenbo Hu ◽  
Xiaogang Wang ◽  
Sanyuan Ma ◽  
Zhangchuan Peng ◽  
Yang Cao ◽  
...  

The silkworm Bombyx mori is an economically important insect, as it is the main producer of silk. Fibroin heavy chain (FibH) gene, encoding the core component of silk protein, is specifically and highly expressed in silk gland cells but not in the other cells. Although the silkworm FibH gene has been well studied in transcriptional regulation, its biological functions in the development of silk gland cells remain elusive. In this study, we constructed a CRISPRa system to activate the endogenous transcription of FibH in Bombyx mori embryonic (BmE) cells, and the mRNA expression of FibH was successfully activated. In addition, we found that FibH expression was increased to a maximum at 60 h after transient transfection of sgRNA/dCas9-VPR at a molar ratio of 9:1. The qRT-PCR analysis showed that the expression levels of cellular stress response-related genes were significantly up-regulated along with activated FibH gene. Moreover, the lyso-tracker red and monodansylcadaverine (MDC) staining assays revealed an apparent appearance of autophagy in FibH-activated BmE cells. Therefore, we conclude that the activation of FibH gene leads to up-regulation of cellular stress responses-related genes in BmE cells, which is essential for understanding silk gland development and the fibroin secretion process in B. mori.


2009 ◽  
Vol 106 (17) ◽  
pp. 7251-7256 ◽  
Author(s):  
Atsushi Fukushima ◽  
Miyako Kusano ◽  
Norihito Nakamichi ◽  
Makoto Kobayashi ◽  
Naomi Hayashi ◽  
...  

In higher plants, the circadian clock controls a wide range of cellular processes such as photosynthesis and stress responses. Understanding metabolic changes in arrhythmic plants and determining output-related function of clock genes would help in elucidating circadian-clock mechanisms underlying plant growth and development. In this work, we investigated physiological relevance of PSEUDO-RESPONSE REGULATORS (PRR 9, 7, and 5) in Arabidopsis thaliana by transcriptomic and metabolomic analyses. Metabolite profiling using gas chromatography–time-of-flight mass spectrometry demonstrated well-differentiated metabolite phenotypes of seven mutants, including two arrhythmic plants with similar morphology, a PRR 9, 7, and 5 triple mutant and a CIRCADIAN CLOCK-ASSOCIATED 1 (CCA1)-overexpressor line. Despite different light and time conditions, the triple mutant exhibited a dramatic increase in intermediates in the tricarboxylic acid cycle. This suggests that proteins PRR 9, 7, and 5 are involved in maintaining mitochondrial homeostasis. Integrated analysis of transcriptomics and metabolomics revealed that PRR 9, 7, and 5 negatively regulate the biosynthetic pathways of chlorophyll, carotenoid and abscisic acid, and α-tocopherol, highlighting them as additional outputs of pseudo-response regulators. These findings indicated that mitochondrial functions are coupled with the circadian system in plants.


2010 ◽  
Vol 40 (2) ◽  
pp. 175 ◽  
Author(s):  
Feng Chen ◽  
Allyson Evans ◽  
John Pham ◽  
Brian Plosky

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