The effect of fatty acids on the metabolism of lactic acid streptococci: I. Inhibition of bacterial growth and proteolysis

1964 ◽  
Vol 31 (1) ◽  
pp. 81-89 ◽  
Author(s):  
R. F. Anders ◽  
G. R. Jago

SummaryThe early loss of viability of Streptococcus cremoris strain C 13 in Cheddar cheese was investigated. The growth of this strain was markedly inhibited by cheese extracts containing unesterified fatty acids of which oleic acid was the major inhibitory constituent active against the coccus. This acid was found to accumulate in cheese early in the ripening process and may be responsible for the early loss of viability of strain C 13 in cheese.Early loss of viability of a starter organism in cheese could result in a low peptidase activity by limiting the number of bacterial cells present. The subsequent accumulation of unhydrolysed bitter peptides would produce a bitter flavour.

1964 ◽  
Vol 31 (1) ◽  
pp. 91-94 ◽  
Author(s):  
R. F. Anders ◽  
G. R. Jago

SummaryIt was previously found that low concentrations of oleic acid in the growth medium inhibited the growth of Streptococcus cremoris strain C 13. However, a variant of this strain has now been isolated which is capable of growth in relatively high concentrations of oleic acid. This was achieved by the extended incubation of inocula of strain C 13 in milk containing various concentrations of oleic acid.


2019 ◽  
Vol 31 (1) ◽  
pp. 201
Author(s):  
E. Menezes ◽  
F. Santos ◽  
A. Velho ◽  
T. Dinh ◽  
A. Kaya ◽  
...  

Sub-fertility fertility in bulls decreases the efficiency and profitability of cattle production because AI allows a single bull to inseminate thousands of cows. In recent decades, there has been a general decline in fertility of bulls, even among those exhibiting normal sperm motility and morphology. Despite advances in technology and knowledge, molecular, cellular and physiological mechanisms underlying the causes of low fertility in bulls are currently unclear. Therefore, the objective of this study was to identify sperm metabolites associated with fertility in Holstein bulls. The metabolome of sperm from 10 mature bulls with high fertility (HF, n=5) and low fertility (LF, n=5) was identified by gas chromatography coupled to mass spectrometry. Bull fertility was based on the sire conception rates deviating from the average. Statistical analysis was performed by using MetaboAnalyst 3.0 (http://www.metaboanalyst.ca/). A total of 22 metabolites were detected and categorized according to their major chemical classes, including amino acids, peptides/analogues, carbohydrates/carbohydrate conjugates, fatty acids, steroids/steroid derivatives, keto acids and derivatives, carboxylic acids, and other organic and inorganic compounds. Organic acids and derivatives as well as fatty acids were the major compounds in bull spermatozoa. Seven organic acids and derivatives were detected, including benzoic acid, carbonate, carbamate dimethyl, carbamate trimethyl, lactic acid, oxalic acid, and urea. Five fatty acids were identified including oleic acid, oleanitrile, nonanoic acid, and palmitic acid. Oleic acid, phosphoric acid, phosphine, carbamate trimethyl, and glycerol were the most abundant metabolites in bull sperm, whereas benzoic acid, acetic acid, l-serine, carbamate, and 2-ketobutyric acid were the least predominant metabolites present in bull sperm. Multivariate analysis (partial least squares-discriminant analysis) of the sperm metabolome showed a clear separation between HF and LF bulls. Variable importance in projection (VIP) score demonstrated that metabolites with VIP >1.5 were gamma-aminobutyric acid (VIP=2.01), carbamate trimethyl (VIP=1.88), benzoic acid (VIP=1.86), and lactic acid (VIP=1.81). Abundance ratios of gamma-aminobutyric acid, carbamate trimethyl, benzoic acid, and lactic acid was greater in HF bulls compared with LF animals. According to univariate analysis, abundance ratios of gamma-aminobutyric acid (P=0.03) and carbamate trimethyl (P=0.047) were greater in HF than in LF bulls. Gamma-aminobutyric acid was positively correlated with carbamate trimethyl (r=0.94; P<0.0001) and benzoic acid (r=0.74; P=0.0139). Benzoic acid was positively correlated with carbamate trimethyl (r=0.75; P=0.0107) and carbamate dimethyl (r=0.68; P=0.0274). The identified metabolites can serve as potential markers to evaluate semen quality and predict bull fertility.


1970 ◽  
Vol 37 (3) ◽  
pp. 445-456 ◽  
Author(s):  
R. F. Anders ◽  
G. R. Jago

SummaryThe metabolism, of pyruvate by resting whole-cell suspensions of Group N streptococci was studied over the pH range 4·0–7·0, in the presence and absence of oleic acid. In the absence of oleic acid pyruvate was utilized maximally at pH 4·5 with the formation of acetate (volatile acid), acetoin + diacetyl and carbon dioxide. The formation of acetate took precedence over the formation of acetoin + diacetyl. In the presenoe of oleic acid the utilization of pyruvate was maximal at pH 6·5 and completely inhibited at pH 4·5. The only products detected at pH 6·5 were acetoin + diacetyl and carbon dioxide. This effect of oleic acid on the metabolism of pyruvate was also obtained after treating the cells with acetone. The mechanism of action of oleic acid on cells of Group N streptococci and its possible influence on the formation of flavour compounds in cultured dairy products is discussed.


Author(s):  
Natalia O. Zhila ◽  
Galina S. Kalacheva ◽  
Viktoriya V. Fokht ◽  
Svetlana S. Bubnova ◽  
Tatiana G. Volova

Polyhydroxyalkanoates have attracted much attention as biodegradable alternative to petroleum-based synthetic plastics. Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] copolymer is one of the best characterized PHA copolymers because of its high commercial potential. However, commercial use of PHAs has been limited by their high price. One approach to reducing the cost of PHA production is to use inexpensive carbon sources (fatty acids, plant oils, etc.). The aim of this work was to study synthesis of P(3HB-co-3HV) by the Cupriavidus necator B-10646 bacterium grown on oleic acid and different biochemical precursors of 3HV. Bacterial cells were grown for 72 h at 30°C and 200 rpm on an incubator shaker. Salts of propionic or valeric acids were used as precursors of 3HV. The content and the composition of the polymer were determined by gas chromatography of fatty acid methyl esters. Lipids and polymer were extracted from biomass using the method of Folch. The addition of potassium propionate and valerate did not inhibit bacterial growth and polymer synthesis, the cell concentration and polymer content reaching 9.3-9.5 g/L and 80-83%, respectively. The addition of potassium valerate or propionate led to the synthesis of (P(3HB-co-3HV)) copolymer containing 21.2 and 14.3 mol% of 3HV, respectively. The number average molecular weight (Mn) of the polymer synthesized by the bacterium on oleic acid alone was 220 kDa; the polydispersity of the polymer was 3.5. The polymer synthesized in the presence of potassium valerate and propionate was characterized by a lower Mn (156-178 kDa) and a higher polydispersity of the polymer (4.4-4.9). The main fatty acids (FA) of intracellular lipids were oleic (33.26% of the total FA) and palmitic acid (27.48% of the total FA). The addition of potassium propionate or valerate did not cause any significant changes in the composition of the FA of intracellular lipids of the strain studied. This study demonstrates the ability of C. necator B-10646 to synthesize P(3HB-co-3HV) from mixtures of oleic acid and 3HV precursors. The data obtained can be used to develop and implement an economically feasible process of the P(3HB-co-3HV) production


2020 ◽  
Author(s):  
Jarrad R Prasifka ◽  
Beth Ferguson ◽  
James V Anderson

Abstract The red sunflower seed weevil, Smicronyx fulvus L., is a univoltine seed-feeding pest of cultivated sunflower, Helianthus annuus L. Artificial infestations of S. fulvus onto sunflowers with traditional (<25% oleic acid), mid-oleic (55–75%), or high oleic (>80%) fatty acid profiles were used to test if fatty acids could be used as natural markers to estimate the proportion of weevils developing on oilseed sunflowers rather than wild Helianthus spp. and confection (non-oil) types. Oleic acid (%) in S. fulvus confirmed the fatty acid compositions of mature larvae and weevil adults reflected their diets, making primary (oleic or linoleic) fatty acids feasible as natural markers for this crop-insect combination. Oleic acid in wild S. fulvus populations in North Dakota suggests at least 84 and 90% of adults originated from mid-oleic or high oleic sunflower hybrids in 2017 and 2018, respectively. Surveys in 2017 (n = 156 fields) and 2019 (n = 120 fields) extended information provided by S. fulvus fatty acid data; no significant spatial patterns of S. fulvus damage were detected in samples, damage to oilseed sunflowers was greater than confection (non-oil) types, and the majority of damage occurred in ≈10% of surveyed fields. Combined, data suggest a few unmanaged or mismanaged oilseed sunflower fields are responsible for producing most S. fulvus in an area. Improved management seems possible with a combination of grower education and expanded use of non-insecticidal tactics, including cultural practices and S. fulvus-resistant hybrids.


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Yu Gao ◽  
Yan Sun ◽  
Huiling Gao ◽  
Ying Chen ◽  
Xiaoqing Wang ◽  
...  

Abstract Background Engineering triacylglycerol (TAG) accumulation in vegetative tissues of non-food crops has become a promising way to meet our increasing demand for plant oils, especially the renewable production of biofuels. The most important target modified in this regard is diacylglycerol acyltransferase (DGAT) enzyme responsible for the final rate-limiting step in TAG biosynthesis. Cyperus esculentus is a unique plant largely accumulating oleic acid-enriched oil in its underground tubers. We speculated that DGAT derived from such oil-rich tubers could function more efficiently than that from oleaginous seeds in enhancing oil storage in vegetative tissues of tobacco, a high-yielding biomass crops. Results Three CeDGAT genes namely CeDGAT1, CeDGAT2-1 and CeDGAT2-2 were identified in C. esculentus by mining transcriptome of developing tubers. These CeDGATs were expressed in tissues tested, with CeDGAT1 highly in roots, CeDGAT2-1 abundantly in leaves, and CeDGAT2-2 predominantly in tubers. Notably, CeDGAT2-2 expression pattern was in accordance with oil dynamic accumulation during tuber development. Overexpression of CeDGAT2-2 functionally restored TAG biosynthesis in TAG-deficient yeast mutant H1246. Oleic acid level was significantly increased in CeDGAT2-2 transgenic yeast compared to the wild-type yeast and ScDGA1-expressed control under culture with and without feeding of exogenous fatty acids. Overexpressing CeDGAT2-2 in tobacco led to dramatic enhancements of leafy oil by 7.15- and 1.7-fold more compared to the wild-type control and plants expressing Arabidopsis seed-derived AtDGAT1. A substantial change in fatty acid composition was detected in leaves, with increase of oleic acid from 5.1% in the wild type to 31.33% in CeDGAT2-2-expressed tobacco and accompanied reduction of saturated fatty acids. Moreover, the elevated accumulation of oleic acid-enriched TAG in transgenic tobacco exhibited no significantly negative impact on other agronomic traits such as photosynthesis, growth rates and seed germination except for small decline of starch content. Conclusions The present data indicate that CeDGAT2-2 has a high enzyme activity to catalyze formation of TAG and a strong specificity for oleic acid-containing substrates, providing new insights into understanding oil biosynthesis mechanism in plant vegetative tissues. Overexpression of CeDGAT2-2 alone can significantly increase oleic acid-enriched oil accumulation in tobacco leaves without negative impact on other agronomy traits, showing CeDGAT2-2 as the desirable target gene in metabolic engineering to enrich oil and value-added lipids in high-biomass plants for commercial production of biofuel oils.


Molecules ◽  
2019 ◽  
Vol 24 (24) ◽  
pp. 4433 ◽  
Author(s):  
Carolina Caicedo ◽  
Rocío Yaneli Aguirre Loredo ◽  
Abril Fonseca García ◽  
Omar Hernán Ossa ◽  
Aldo Vázquez Arce ◽  
...  

The modification of achira starch a thermoplastic biopolymer is shown. Glycerol and sorbitol, common plasticizers, were used in the molten state with organic acids such as oleic acid and lactic acid obtaining thermodynamically more stable products. The proportion of starch:plasticizer was 70:30, and the acid agent was added in portions from 3%, 6%, and 9% by weight. These mixtures were obtained in a torque rheometer for 10 min at 130 °C. The lactic acid managed to efficiently promote the gelatinization process by increasing the available polar sites towards the surface of the material; as a result, there were lower values in the contact angle, these results were corroborated with the analysis performed by differential scanning calorimetry and X-ray diffraction. The results derived from oscillatory rheological analysis had a viscous behavior in the thermoplastic starch samples and with the presence of acids; this behavior favors the transitions from viscous to elastic. The mixture of sorbitol or glycerol with lactic acid promoted lower values of the loss module, the storage module, and the complex viscosity, which means lower residual energy in the transition of the viscous state to the elastic state; this allows the compounds to be scaled to conventional polymer transformation processes.


1951 ◽  
Vol 18 (2) ◽  
pp. 198-204 ◽  
Author(s):  
A. Hirsch ◽  
Elisabeth Grinsted

Twenty-three strains of lactic acid streptococci were shown to be types ofStreptococcus cremorisorStr. lactisby cultural, biochemical and serological means. The antibiotics produced by thecremorisstrains could be differentiated readily from thelactisantibiotics, of which at least five different varieties are described. A cross-test and a resistant-strain test were used to differentiate the antibiotics.


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