Pozadina istraživanja. Pri današnjoj proizvodnji mlijeka u razvijenim zemljama te onima u razvoju, nekoliko čimbenika utječe na trajnost sirovog mlijeka i pojačava kontaminaciju patogenim ...mikroorganizmima, što bitno utječe na inicijalnu populaciju mikroorganizama i uzrokuje kvarenje mlijeka prije početka obrade. Eksperimentalni pristup. U ovom je radu ispitana učinkovitost reuterina kao biokonzervansa u različitim kombinacijama s bakteriocinima za kontrolu mikroflore sirovog mlijeka na farmi. U našem je prethodnom radu zbog izražene antimikrobne aktivnosti od nekoliko sojeva bakterija odabran soj Lactobacillus reuteri LR47, te je ispitana njegova sposobnost proizvodnje reuterina u sirovom mlijeku. Rezultati i zaključci. Preliminarni su testovi pokazali da je supernatant bez stanica bakterije L. reuteri LR47 bitno inhibirao rast većine ispitanih uzročnika kvarenja mlijeka. Daljnje genetičke analize soja otkrile su prisutnost dvaju gena (pduC i dhaB) odgovornih za iskorištenje glicerola tijekom dva različita metabolička puta proizvodnje reuterina. Osim toga, kolorimetrijskom je analizom otkriveno da soj LR47 ima veću sposobnost konverzije glicerola u reuterin od ostalih sojeva bakterija. Pri ispitivanju postupaka biološkog konzerviranja sirovog mlijeka pomoću reuterina ili reuterina u kombinaciji s bakteriocinima, najizraženije je svojstvo inhibicije ukupnog broja mikroorganizama i broja koliformnih bakterija zapaženo u uzorku mlijeka tretiranog kombinacijom reuterina, nizina i pediocina. Broj mikroorganizama i fizikalno-kemijska svojstva, kao što su pH-vrijednost i titracijska kiselost, pokazali su da se kombinacijom određenih koncentracija tih triju prirodnih biokonzervansa očuvala početna mikrobiološka kakvoća mlijeka, te produljila njegova trajnost za 6 sati pri 37 °C. Dobiveni rezultati potvrđuju da se primjenom reuterina u kombinaciji s bakteriocinima može privremeno kontrolirati mikroflora sirovog mlijeka, te produljiti njegova trajnost do daljnje prerade. Novina i znanstveni doprinos. U ovom je radu po prvi put opisana primjena reuterina kao alternativnog postupka produljenja trajnosti sirovog mlijeka.
In the current scenario of milk production in developing and developed countries, several factors influence the shelf-life of raw milk and add significant numbers of microbial contaminants that ...drastically lower the initial microbial quality leading to milk spoilage by the time it reaches the processing units.
The present study was undertaken to investigate the biopreservative efficacy of reuterin system along with different combinations of bacteriocins in controlling the initial microflora of raw milk at farm level.
strain LR47, having effective antimicrobial activity, was shortlisted from our previous study and further characterized for reuterin production and tested in raw milk system.
Preliminary testing of the cell-free supernatant from
LR47 demonstrated significant growth inhibition of the majority of the tested bacterial indicators of milk spoilage. Further genetic analysis of the
LR47 revealed the presence of two genes (
and
) involved in the utilization of glycerol to produce reuterin
two different pathways. The strain LR47 was also found to possess comparatively higher capacity to convert glycerol into reuterin when checked through colorimetric assay. In the raw milk biopreservation experiment with reuterin alone or in combination with bacteriocins, the highest level of growth suppression in the total bacterial load and coliform counts was observed in the sample that was treated with a combination of reuterin, nisin and pediocin. The treatment combining these three natural biopreservatives at specific concentrations was able to maintain the initial microbial quality and extend the shelf-life of raw milk by 6 h at 37 °C based on the microbial counts and physicochemical properties,
. pH and titratable acidity. In conclusion, the results confirm that the use of reuterin in combination with bacteriocins is a promising approach for temporary control of the raw milk microflora and extension of its shelf-life until further processing.
This study demonstrates for the first time the use of reuterin for the extension of shelf-life of raw milk as an alternative treatment method.
Protective antigen (PA) is the main component of all the vaccines against anthrax. The currently available vaccines have traces of other proteins that contribute to its reactogenicity. Thus, purified ...PA is recommended for human vaccination. PA loses its biological activity within 48
h at 37
°C and its thermolability has been a cause of concern as accidental exposure to higher temperatures during transportation or storage could decrease its efficacy. In the present study, we have used protein engineering approach to increase the thermostability of PA by mutating amino acid residues on the surface as well as the interior of the protein. After screening several mutants, the mutants Gln277Ala and Phe554Ala have been found to be more thermostable than the wild-type PA. Gln277Ala retains ∼45% and Phe554Ala retains ∼90% activity, even after incubation at 37
°C for 48
h while in the same period wild-type PA loses its biological activity completely. It is the first report of increasing thermostability of PA using site-directed mutagenesis. Generation of such mutants could pave the way for better anthrax vaccines with longer shelf life.
Research background. In the current scenario of milk production in developing and developed countries, several factors influence the shelf-life of raw milk and add significant numbers of microbial ...contaminants that drastically lower the initial microbial quality leading to milk spoilage by the time it reaches the processing units.
Experimental approach. The present study was undertaken to investigate the biopreservative efficacy of reuterin system along with different combinations of bacteriocins in controlling the initial microflora of raw milk at farm level. Lactobacillus reuteri strain LR47, having effective antimicrobial activity, was shortlisted from our previous study and further characterized for reuterin production and tested in raw milk system.
Results and conclusions. Preliminary testing of the cell-free supernatant from L. reuteri LR47 demonstrated significant growth inhibition of the majority of the tested bacterial indicators of milk spoilage. Further genetic analysis of the L. reuteri LR47 revealed the presence of two genes (pduC and dhaB) involved in the utilization of glycerol to produce reuterin via two different pathways. The strain LR47 was also found to possess comparatively higher capacity to convert glycerol into reuterin when checked through colourimetric assay. In the raw milk biopreservation experiment with reuterin alone or in combination with bacteriocins, the highest level of growth suppression in the total bacterial load and coliform counts was observed in the sample that was treated with a combination of reuterin, nisin and pediocin. The treatment combining these three natural biopreservatives at specific concentrations was able to maintain the initial microbial quality and extend the shelf-life of raw milk by 6 h at 37 °C based on the microbial counts and physicochemical properties, viz. pH and titratable acidity. In conclusion, the results confirm that the use of reuterin in combination with bacteriocins is a promising approach for temporary control of the raw milk microflora and extension of its shelf-life until further processing.
Novelty and scientific contribution. This study demonstrates for the first time the use of reuterin for the extension of shelf-life of raw milk as an alternative treatment method.
The fruits of
(TB) and seeds of
(TF) are used for their nutraceutical properties in various systems of traditional medicine practiced in India. In this study aqueous and methanolic extracts of TB ...fruits and TF seeds were prepared and their protective effect was studied on hydrogen peroxide (H
O
)-treated neuroblastoma (NB-41) cell line. Cell viability, nitric oxide (NO) levels, mRNA, and protein profiles were analyzed and compared with untreated control. Results show that aqueous extracts of both TB and TF provide significant protection to neuroblastoma cells with TF aqueous extract offering better protection through upregulation of neuronal nitric oxide synthase (nNOS) against hydrogen peroxide generated stress. This is the first report demonstrating protection of neuronal cell lines by use of TB and TF extracts through modulation of nNOS activity.
The anthrax toxin consists of protective antigen (PA), lethal factor (LF) and edema factor (EF). PA mediates the entry of LF and EF to the cytosol where they exert their effects. Although PA is the ...major component of the vaccines against anthrax, LF has also been found to play an important role in enhancing protective immunity. We have developed an osmolyte-inducible LF expression system. The protein expression system contributed no additional amino acids to the recombinant LF making it suitable for the human vaccine trials.
Although the insertion of heme into proteins enables their function in bioenergetics, metabolism, and signaling, the mechanisms and regulation of this process are not fully understood. We developed a ...means to study cellular heme insertion into apo-protein targets over a 3-h period and then investigated how nitric oxide (NO) released from a chemical donor (NOC-18) might influence heme (protoporphyrin IX) insertion into seven targets that present a range of protein structures, heme ligation states, and functions (three NO synthases, two cytochrome P450's, catalase, and hemoglobin). NO blocked cellular heme insertion into all seven apo-protein targets. The inhibition occurred at relatively low (nM/min) fluxes of NO, was reversible, and did not involve changes in intracellular heme levels, activation of guanylate cyclase, or inhibition of mitochondrial ATP production. These aspects and the range of protein targets suggest that NO can act as a global inhibitor of heme insertion, possibly by inhibiting a common step in the process.
Yoga and breathing techniques have become increasingly popular in recent decades. Sudarshan Kriya (SK) is a type of rhythmic and controlled breathing that involves cyclic breathing in which long ...breaths are followed by medium and short breaths. Scientific research has been conducted to study the effects of SK on different physiological parameters. Various studies have shown that the technique is simple and cost effective and can be used as a complementary therapy, together with ongoing conventional treatments, to help people suffering from extreme levels of stress, anxiety, and other physical problems. Studies have demonstrated that SK can play an important role in promoting a healthy lifestyle by improving immunity, antioxidant status, hormonal status, and brain functioning. Through available scientific evidence and research, the current article aims to review the complementary role of rhythmic breathing (ie, SK) as a practical and effective tool to alleviate stress, improve health, and increase wellness.
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