scholarly journals Mechanisms of lactic acid gustatory attraction in Drosophila

2021 ◽  
Author(s):  
Molly Stanley ◽  
Britya Ghosh ◽  
Zachary F. Weiss ◽  
Jaime Christiaanse ◽  
Michael D. Gordon

SUMMARYSour has been studied almost exclusively as an aversive taste modality. Yet, recent work in Drosophila demonstrates that specific carboxylic acids are attractive at ecologically relevant concentrations. Here, we demonstrate that lactic acid is an appetitive and energetic tastant, which stimulates feeding through activation of sweet gustatory receptor neurons (GRNs). This activation displays distinct, mechanistically separable, stimulus onset and removal phases. Ionotropic receptor 25a (IR25a) primarily mediates the onset response, which shows specificity for the lactate anion and drives feeding initiation. Conversely, sweet gustatory receptors (Gr64a-f) mediate a non-specific removal response to low pH that primarily impacts ingestion. While mutations in either receptor family have marginal impacts on feeding, lactic acid attraction is completely abolished in combined mutants. Thus, specific components of lactic acid are detected through two classes of receptors to activate a single set of sensory neurons in physiologically distinct ways, ultimately leading to robust behavioural attraction.

Author(s):  
Maria D Ferrer ◽  
Salvadora Pérez ◽  
Aránzazu López Lopez ◽  
José Luis Sanz ◽  
Maria Melo ◽  
...  

Our aim was to evaluate clinical, biochemical and microbiological markers related to dental caries in adults. A sample that consisted of 75 volunteers was utilized. The presence of caries and the presence of plaque and gingival indices were determined. Unstimulated salivary flow, pH, lactate, Streptococcus mutans and Streptococcus dentisani were measured in the participants’ plaque and saliva samples before and after rinsing with a sugar solution. Lactate in plaque was found to be significantly related to age, gender, tooth-brushing frequency, the presence of cavitated caries lesions and plaque and gingival indices (p < 0.05). The levels of S. dentisani in plaque increased significantly with tooth-brushing frequency (p = 0.03). Normalized plaque S. dentisani values and the percentage of S. dentisani were slightly higher in patients with basal lactic acid levels ≤ 50 mg/L. After rinsing with a sugary solution, the percentage of S. mutans levels in plaque were higher in patients with lactic acid levels > 350 mg/L (p = 0.03). Tooth-brushing frequency was the factor which was most associated with oral health. Women reflected better clinical and biochemical parameters than men. Low pH and high lactic acid levels tended to be associated with high caries rates. No association was found between bacteria levels and caries indices.


2019 ◽  
Vol 7 (1) ◽  
pp. 1 ◽  
Author(s):  
Nurul Octavia Wasis ◽  
Nyoman Semadi Antara ◽  
Ida Bagus Wayan Gunam

Tabah bamboo shoot pickle is one of the fermented food which is the source of lactic acid bacteria.  Lactic acid bacteria (LAB) is beneficial to health because it has the ability as a probiotic. Lactic acid bacteria that have probiotic criteria should have resistance to low pH and bile salts. This study aims to determine isolates of lactic acid bacteria isolated from tabah bamboo shoot pickle resistant to low pH and bile salts (NaDC). Lactic acid bacteria were tested to low pH by using MRS broth that have different pH (pH 2, pH 3, pH 4 and pH 6.2 as a control) incubated at 37ºC for 3 hours. isolates were survive in low pH then continued in bile salt resistance test with 0.3% bile salt concentration for 15 minutes, 30 minutes, 45 minutes, 60 minutes and 24 hours. The results showed that three isolates out of 88 isolates had ability to grow in low pH and in medium supplemented by NaDC 0,3%. The isolates are AR 3057, AR 3101 and AR 6152 which can be used as candidat of  probiotic. Keywords : Tabah bamboo shoot pickle, lactic acid bacteria, probiotic, low pH, bile salt


2001 ◽  
Vol 1 ◽  
pp. 510-512 ◽  
Author(s):  
D.C. Immke ◽  
E.W. McCleskey

Angina, the prototypic vasoocclusive pain, is a radiating chest pain that occurs when heart muscle gets insufficient blood because of coronary artery disease. Other examples of vasoocclusive pain include the acute pain of heart attack and the intermittent pains that accompany sickle cell anemia and peripheral artery disease. All these conditions cause ischemia � insufficient oxygen delivery for local metabolic demand — and this releases lactic acid as cells switch to anaerobic metabolism. Recent discoveries demonstrate that sensory neurons innervating the heart are richly endowed with an ion channel that is opened by, and perfectly tuned for, the lactic acid released by muscle ischemia[1,2].


2018 ◽  
Vol 6 (1) ◽  
pp. 49-58
Author(s):  
Yenni Okfrianti ◽  
Darwis Darwis ◽  
Ayu Pravita

Based on previous research it was found that lemea (traditional food rejang) was proven to contain 2 types of lactic acid bacteria (BAL) namely L.aplantarum C410L1 and L. crossiae LS6 which could be probiotic and beneficial for health. The development of lemea as a potential probiotic must be proven its resistance to bile acids and salts as an indication of being able to survive in the gastrointestinal tract. This study aims to determine the resistance of BAL isolated from lemea against low pH, bile acids, and temperature. This research is an experimental study with all research units controlled. Analysis of BAL resistance to high temperatures, low pH, and bile salts was carried out in the Bengkulu Polytechnic Health Polytechnic laboratory. The total BAL colonies increased at 49 ° C and decreased at 64 ° C. The increase in the total number of BAL colonies within 0-30 hours occurred at pH 5 and pH 6. There was no increase or decrease in the total number of BAL colonies in salts 0.30%, 0.60%, and 0.90%. The diisolate lactic acid (BAL) bacteria from lemea have a temperature resistance of 42 ° C to 64 ° C, pH 2 to pH 7, have a salt resistance concentration of 0.30% to 0.90%. Lactic acid bacteria (BAL) which are diisolate from lemea have the potential as probiotics.


Author(s):  
Cristobal A. Onetto ◽  
Peter J. Costello ◽  
Radka Kolouchova ◽  
Charlotte Jordans ◽  
Jane McCarthy ◽  
...  

Malolactic fermentation is an indispensable step in the elaboration of most wines and is generally performed by Oenococcus oeni , a Gram-positive heterofermentative lactic acid bacterium species. While O. oeni is tolerant to many of the wine stresses, including low pH and high ethanol concentrations, it has high sensitivity to SO 2 , an antiseptic and antioxidant compound regularly used in winemaking.


eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Ji-Eun Ahn ◽  
Yan Chen ◽  
Hubert Amrein

Behavioral studies have established that Drosophila appetitive taste responses towards fatty acids are mediated by sweet sensing Gustatory Receptor Neurons (GRNs). Here we show that sweet GRN activation requires the function of the Ionotropic Receptor genes IR25a, IR76b and IR56d. The former two IR genes are expressed in several neurons per sensillum, while IR56d expression is restricted to sweet GRNs. Importantly, loss of appetitive behavioral responses to fatty acids in IR25a and IR76b mutant flies can be completely rescued by expression of respective transgenes in sweet GRNs. Interestingly, appetitive behavioral responses of wild type flies to hexanoic acid reach a plateau at ~1%, but decrease with higher concentration, a property mediated through IR25a/IR76b independent activation of bitter GRNs. With our previous report on sour taste, our studies suggest that IR-based receptors mediate different taste qualities through cell-type specific IR subunits.


2017 ◽  
Vol 4 (2) ◽  
pp. 263
Author(s):  
Ida Ayu Ketut Ariningsih ◽  
Yan Ramona ◽  
Nyoman Semadi Antara

Candidacies in female reproductive tract are mainly caused by Candida albicans. This infection often causes serious problems, particularly on their reproductive tract (genital part). Until recently, control of this infection has relied on the use of antibiotics. However due to numerous bad side effects of antibiotics, lactic acid bacteria have been proposed as an alternative method to control the growth of Candida albicans. Therefore, this research was aimed to isolate, screen, and characterize lactic acid bacterial isolates (LAB) antagonistic against Candida albicans (the causative agent of candidacies infection in reproductive tract of human). LABs were isolated from various fermented foods, such as tape ketan and kimchi. Isolation of LABs was conducted by applying dilution and spread plate method on MRS agar medium supplemented with BCP indicator to distinguish LABs from non acid-producing bacteria. Colonies with indication to produce acid were screened for antagonistic activity against C. albicans on MRS agar and followed by characterization of those isolates (Gram stain, catalase production test, oxydase production, gas production test, resistance test to low pH conditions and to high level of NaDC (sodium deoxicolic), and test for ability to convert colic acid (CA) into deoxicolic acid (DCA)). The results showed that 46 LAB isolates were successfully isolated from samples of tape ketan and kimchi. Among those, 7 isolates showed antagonistic activity against C. albicans in in vitro tests. All these 7 candidates were also found to be resistance to low pH conditions (up to pH 2) and to high level of NaDC (up to 0.6 mM). Four most potential isolates were further testes for ability to convert colic acid into deoxycolic acid and none showed positive result, indicating that they all showed initial potential and safe for future human probiotic development (especially to be used to treat patients infected by C. albicans).


2006 ◽  
Vol 72 (8) ◽  
pp. 5492-5499 ◽  
Author(s):  
Minoska Valli ◽  
Michael Sauer ◽  
Paola Branduardi ◽  
Nicole Borth ◽  
Danilo Porro ◽  
...  

ABSTRACT Yeast strains expressing heterologous l-lactate dehydrogenases can produce lactic acid. Although these microorganisms are tolerant of acidic environments, it is known that at low pH, lactic acid exerts a high level of stress on the cells. In the present study we analyzed intracellular pH (pHi) and viability by staining with cSNARF-4F and ethidium bromide, respectively, of two lactic-acid-producing strains of Saccharomyces cerevisiae, CEN.PK m850 and CEN.PK RWB876. The results showed that the strain producing more lactic acid, CEN.PK m850, has a higher pHi. During batch culture, we observed in both strains a reduction of the mean pHi and the appearance of a subpopulation of cells with low pHi. Simultaneous analysis of pHi and viability proved that the cells with low pHi were dead. Based on the observation that the better lactic-acid-producing strain had a higher pHi and that the cells with low pHi were dead, we hypothesized that we might find better lactic acid producers by screening for cells within the highest pHi range. The screening was performed on UV-mutagenized populations through three consecutive rounds of cell sorting in which only the viable cells within the highest pHi range were selected. The results showed that lactic acid production was significantly improved in the majority of the mutants obtained compared to the parental strains. The best lactic-acid-producing strain was identified within the screening of CEN.PK m850 mutants.


2001 ◽  
Vol 64 (8) ◽  
pp. 1145-1150 ◽  
Author(s):  
NAVEEN CHIKTHIMMAH ◽  
RAMASWAMY C. ANANTHESWARAN ◽  
ROBERT F. ROBERTS ◽  
EDWARD W. MILLS ◽  
STEPHEN J. KNABEL

Due to undesirable quality changes, Lebanon bologna is often processed at temperatures that do not exceed 48.8°C (120°F). Therefore, it is important to study parameters that influence the destruction of Escherichia coli O157:H7 in Lebanon bologna. The objective of the present study was to determine the influence of curing salts (NaCl and NaNO2) on the destruction of E. coli O157:H7 during Lebanon bologna processing. Fermentation to pH 4.7 at 37.7°C reduced populations of E. coli O157:H7 by approximately 0.3 log10, either in the presence or absence of curing salts. Subsequent destruction of E. coli O157:H7 during heating of fermented product to 46.1°C was significantly reduced by the presence of 3.5% NaCl and 156 ppm NaNO2, compared to product without curing salts (P &lt; 0.01). The presence of a higher level of NaCl (5%) in Lebanon bologna inhibited the growth of lactic acid bacteria (LAB), which yielded product with higher pH (~5.0) and significantly reduced the destruction of E. coli O157:H7 even further (P &lt; 0.05). Lower concentrations of NaCl (0, 2.5%) yielded Lebanon bologna with higher LAB counts and lower pHs, compared to product with 5% NaCl. When lactic acid was used to adjust pH in product containing different levels of NaCl, it was determined that low pH was directly influencing destruction of E. coli O157:H7, not NaCl concentration.


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