Extracellular proteinases in natural isolates of Staphylococci

U ovom radu su detaljnije biohemijski okarakterisane proteinaze prirodnih izolata Staphylococcus sp. F22, F86, M104, S2007 i S2105. Utvrđeno je da se radi o proteinazama relativno male molekulske mase (od 20 do 32 kDa) koje spadaju u prave ekstracelularne enzime, pošto se sa površine ćelije odvajaju u medijum za rast. Temperaturni optimumi ovih proteinaza se kreću od 30 do 37°C, a pH optimumi u opsegu od 6,5 do 8. Joni bakra inhibiraju njihovu aktivnost, dok joni kalcijuma stimulišu aktivnost proteinaza iz izolata F22 M104 i S2007. Pored kazeinskih frakcija, proteinaze stafilokoka hidrolizuju i druge proteinske supstrate, kao što su želatin i BSA. U eksperimentima sa proteinaznim inhibitorima utvrđeno je da proteinaze izolata F22 i M104 pripadaju serinskoj klasi, proteinaze S2007 i S2105 klasi metaloproteinaza dok proteinazu izolata F86 na ovaj način nije bilo moguće precizno klasifikovati.Biochemical characteristics of proteinases from natural isolates of Staphylococcus sp. F22, F86, M104, S2007 and S2105 have been studied. It was found that these proteinases have relatively low molecular masses (from 20 to 32 kDa), and that they are released from the cell envelope in to the growth medium. Their temperature optima are between 30 and 37°C and their pH optima range from 6,5 to 8. Copper ions inhibit their activity, but the presence of calcium ions stimulates the activity of proteinases from isolates F22, M104 and S2007. Beside casein fractions, they also hydrolyze heterologous protein substrates, such as BSA and gelatin. Experiments with specific proteinase inhibitors revealed that proteinases from isolates F22 and M104 belong to the serine group of proteinases, S2007 and S2105 proteinases were classified as metalloproteinases. Type of F86 proteinase in these experiments could not be clearly determinated

Influence of carbohydrates on cell properties of Lactobacillus rhamnosus

Lactobacilli represent normal commensals of the human body, particularly in the gut and vagina where they protect these environments from incoming pathogens via a variety of mechanisms. The influence of the carbohydrate source present in reconstituted MRS growth medium on the different cell properties of two Lactobacillus rhamnosus strains were examined. Two human vaginal isolates, BGHV719 and exopolysaccharide producer strain BGHV954 were analyzed. The results demonstrated that unlike in reconstituted MRS with glucose as a carbon source, the presence of fructose, mannose, or rhamnose, significantly reduced cell surface hydrophobicity of both strains. In addition, differences in cell wall protein composition of L. rhamnosus BGHV719 and alterations in colony mucoidity of L. rhamnosus BGHV954 were also demonstrated. Light and SEM microscopy revealed differences on the cellular level when BGHV719 was cultivated in the presence of different sugars. The results of this study point out the importance of complex relationships between growth medium composition and the different aspects of bacterial behavior, and call for more detailed analyses of versatile bacterial responses to the changes in the environment, including vaginal ecosystem. This is especially important since lactobacilli are amongst the most widely used of probiotics

Analysis of natural isolates of Lactobacilli resistant to bacteriocin nisin

Kolekcija bakterija mlečne kiseline (BMK) je napravljena od mikroorganizama izolovanih iz fermentisanih mlečno-kiselinskih proizvoda dobijenih na tradicionalan način. Iz kolekcije 51 izolat je identifikovan kao Lactobacillus sp. Svi izolovani laktobacili pripadaju grupi mezofilnih sojeva koji dobro rastu na temperaturama od 15°C i 30°C, a ne rastu na temperaturi od 45°C. Testiranje sposobnosti rasta u prisustvu nizina pokazalo je da su izolati BGCGK4, BGHN40, BGBUK2-8, BGBUK2-7 i BGBUK2-16 rezistentni na bakteriocin nizin. U eksperimentu određivanja minimalne inhibitorne koncentracije (MIK) za nizin pokazano je da je najrezistentniji izolat Lactobacillus sp. BGCGK4. Izolat BGBUK2-16, determinisan kao Lactobacillus paracasei subsp. paracasei, produkuje bakteriocin označen kao Bac217 i pokazuje rezistenciju na 8000 IU/ml. Čišćenjem plazmida iz soja BGBUK2-16 dobijena su 2 derivata označena kao BGBUK2-16/K2 i BGBUK2-16/K4. Derivat BGBUK2-16/K2 zadržao je rezistenciju na Bac217 i nizin, ali je izgubio sposobnost sinteze Bac217, dok je derivat BGBUK2-16/K4 pored gubitka sposobnosti sinteze Bac217 postao senzitivan na Bac217 i nizin. Prirodno rezistentni laktobacili se mogu iskoristiti za pripremanje starter kultura u kombinaciji sa nizinom kao konzervansom u cilju kontrolisane mlečno-kiselinske fermentacije.The collection of lactic acid bacteria (LAB) was made by isolation of microorganisms from fermented products traditionally manufactured in different geographical regions (high mountains, river valleys, seaside, etc). Among collected LAB, 51 isolates were identified as Lactobacillus sp. Results showed that all isolated lactobacilli were mesophilic strains, since they grew at 15°C and 30°C but not at 45°C. Testing the ability of isolated lactobacilli to grow in the presence of nisin revealed that Lactobacillus sp. isolates designed BGCGK4, BGHN40, BGBUK2-8, BGBUK2-7 and BGBUK2-16 were resistant to nisin. Determination of the minimal inhibitory concentrations (MIC) for nisin revealed that the most resistant isolate was Lactobacillus sp. BGCGK4. Isolate BGBUK2-16, determined as Lactobacillus paracasei subsp. paracasei, produces bacteriocin, named Bac217 and showed a resistance to 8000 IU/ml of nisin. Plasmid curing of BGBUK2-16 resulted in derivatives BGBUK2-16/K2 and BGBUK2-16/K4. Derivative BGBUK2-16/K2 retained resistance to Bac217 and nisin, but lost the ability to synthesise Bac217. Derivative BGBUK2-16/K4 lost concomitantly the resistance to both Bac217 and nisin

The presence of prtP proteinase gene in natural isolate Lactobacillus plantarum BGSJ3-18

Aims: The study of proteolytic activity and examination of proteinase gene region organization in proteolytically active Lactobacillus plantarum strains from different natural sources. Methods and Results: A set of 37 lactobacilli was distinguished by using multiplex PCR assay. Results showed that 34 strains were Lact. plantarum and three of them were Lact. paraplantarum. The examination of proteolytic activity revealed that 28 Lact. plantarum and two Lact. paraplantarum hydrolyse beta-casein. Further analyses of all proteolytically active Lact. plantarum with primers specific for different types of CEPs demonstrated that strain BGSJ3-18 has prtP catalytic domain as well as prtP-prtM intergenic region showing more than 95% sequence identity with the same regions present in Lact. paracasei, Lact. casei and L. lactis. No presence of prtB, prtH or prtR proteinase genes was detected in any of tested Lact. plantarum strains. Conclusions: One out of 28 analysed Lact. plantarum strains harbours the prtP-like gene. The other proteolytically active Lact. plantarum probably possesses a different type of extracellular proteinase(s). Significance and Impact of the Study: It is the first report about the presence of the prtP-like gene in Lact. plantarum, which illustrates the mobility of this gene and its presence in different species

Retraction notice to: Kojić, M.; Lozo, J.; Jovčić, B.; Strahinić, I.; Fira, Đ.; Topisirović, L. A Successful Use of a New Shuttle Cloning Vector pA13 for the Cloning of the Bacteriocins BacSJ and Acidocin 8912. Archives of Biological Sciences 2010, 62 (2), 231–243. https://doi.org/10.2298/ABS1002231K.

Retraction notice to: Kojić, M.; Lozo, J.; Jovčić, B.; Strahinić, I.; Fira, Đ.; Topisirović, L. A Successful Use of a New Shuttle Cloning Vector pA13 for the Cloning of the Bacteriocins BacSJ and Acidocin 8912. Archives of Biological Sciences 2010, 62 (2), 231–243. [https://doi.org/10.2298/ABS1002231K]

Examination of antimicrobial potential in natural isolates of lactobacillus casei/paracasei group

Cilj ove studije je izučavanje antimikrobnog potencijala 52 prirodna izolata vrste L. casei/paracasei. Učestalost gena koji kodiraju BacSJ (bacSJ2-8/bacSJ2-8i genski klaster), acidocin 8912 (acdT), ABC-transporter (abcT) i pomoćni protein (acc) su takođe izučavani. Genski klaster bacSJ2-8/bacSJ2-8i prisutan je kod 49 (94.23%), a acdT kod 41 (78.85%) od 52 testirana soja. Četrdeset sojeva (76.92%) poseduje oba analizirana gena. Interesantno je da samo 17 sojeva (32.69%) koji poseduju bacSJ2-8/bacSJ2-8i genski klaster i/ili acdT gen proizvode bakteriocine. Soj L. paracasei BGNK1-62 poseduje bacSJ2-8/bacSJ2-8i genski klaster, ali ne proizvodi bakteriocin BacSJ što je verovatno posledica nedostatka abcT i acc gena. Nakon transformacije soja BGNK1-62 konstruktom pA2A koji poseduje abcT i acc gene ostvarena je proizvodnja bakteriocina BacSJ. Osim toga, utvrđeno je da soj L. paracasei BGGR2-66 proizvodi nov bakteriocin označen kao BacGR, koji je biohemijski okarakterisan, a određena je i njegova N-terminalna sekvenca.The aim of this study was to investigate the antimicrobial potential of 52 natural isolates of Lactobacillus casei/paracasei. The incidence of relevant genes encoding BacSJ (bacSJ2-8/bacSJ2-8i gene cluster), acidocin 8912 (acdT), ABC-transporter (abcT) and accessory protein (acc) was also studied. These genes were found to be widespread amongst the analyzed L. casei/paracasei strains. The bacSJ2-8/bacSJ2-8i gene cluster was present in 49 (94.23%) and acdT in 41 (78.85%) of the 52 tested strains. Forty of these strains (76.92%) harbored both analyzed genes. Interestingly, only 17 strains (32.69%) with the bacSJ2-8/bacSJ2-8i gene cluster and/or the acdT gene showed bacteriocin production. Strain L. paracasei BGNK1-62 contained the bacSJ2-8/bacSJ2-8i gene cluster, but did not produce bacteriocin BacSJ possibly due to absence of the abcT and acc genes. Hence, these genes were introduced into BGNK1-62 by transformation with constructed plasmid pA2A, after which BacSJ was produced. In addition, it was found that L. paracasei BGGR2-66 produced new bacteriocin designated as BacGR that was biochemically characterized and its N- terminal sequence was determined

Characterization and antimicrobial activity of natural isolate Lactococcus lactis subsp. lactis BGSM1-19

Soj Lactococcus lactis subsp. lactis BGSM1-19, izolovan iz sira tradicionalno proizvedenog u domaćinstvu, sintetiše dva bakteriocina: bakteriocin BacSMa koji pripada grupi laktokokcina B i bakteriocin BacSMb koji pokazuje visoku homologiju sa lakticinom RM. Čišćenjem plazmida, sa relativno niskim prinosom (0,33%), dobijene su dve grupe derivata: BacSMa- BacSMas derivat i BacSMa- BacSMas, BacSMb-, BacSMbs.. Sinteza bakteriocina je ispitivana tokom logaritamske faze rasta pri čemu je utvrđen maksimum proizvodnje u kulturi staroj 8 sati gajenoj na temperaturi od 30oC, što odgovara ranoj stacionarnoj fazi rasta. Biohemijska karakterizacija je ukazala da soj BGSM1-19 zadržava antimikrobnu aktivnost u opsegu pH vrednosti od 1 do 12 kao i posle tretmana na 100 oC u trajanju od 15 minuta. Utvrđeno je da se antimikrobna aktivnost potpuno gubi nakon tretmana različitim proteolitičkim enzimima. Soj BGSM1-19 poseduje pet plazmida. U eksperimentima čišćenja od plazmida utvrđeno je da se geni za sintezu i imunost na bakteriocine nalaze na plazmidima. Pored toga, BGSM1-19 pokazuje antimikrobnu aktivnost na ispitivane patogene bakterije kao što su Salmonella paratyphi, Micrococcus flavus, Pseudomonas aeruginosa i Staphylococcus aureus.The strain Lactococcus lactis subsp. lactis BGSM1-19, isolated from traditionally homemade white cheese, produces two bacteriocins: lactococcin B-like bacteriocin named bacteriocin BacSMa and bacteriocin BacSMb which have shown similarity with lacticin RM. Plasmid curing resulted in a low yield (0.33%) of BacSMa- BacSMas and BacSMa- BacSMas, BacSMb-, BacSMbs derivatives. The bacteriocin biosynthesis was observed in the logarithmic phase of growth and the production plateau was reached after 8 h of incubation at 30oC, when the culture entered the early stationary phase. Biochemical characterization showed that strain BGSM1-19 retained antimicrobial activity within the pH range of 1 to 12 or after treatment at 100oC for 15 min. However, bacteriocin activity was completely lost after treatment with different proteolytic enzymes. The strain BGSM1-19 contains five plasmids. Plasmid curing indicated that genes coding for bacteriocins synthesis and immunity seem to be located on plasmids. BGSM1-19 exhibited antimicrobial activity against some pathogenic bacteria such as Salmonella paratyphi, Micrococcus flavus, Pseudomonas aeruginosa and Staphylococcus aureus

A successful use of a new shuttle cloning vector pA13 for the cloning of the bacteriocins BacSJ and acidocin 8912

The aim of this paper was to research the molecular cloning of genes encoding the novel bacteriocin BacSJ from Lactobacillus paracasei subsp. paracasei BGSJ2-8 by using a newly constructed shuttle cloning vector pA13. A new shuttle-cloning vector, pA13, was constructed and successfully introduced into Escherichia coli, Lactobacillus and Lactococcus strains, showing a high segregational and structural stability in all three hosts. The natural plasmid pSJ2-8 from L. paracasei subsp. paracasei BGSJ2-8 was cloned in the pA13 using BamHI, obtaining the construct pB5. Sequencing and in silico analysis of the pB5 revealed 15 open reading frames (ORF). Plasmid pSJ2-8 harbors the genes encoding the production of two bacteriocins, BacSJ and acidocin 8912. The combined N-terminal amino acid sequencing of BacSJ in combination with DNA sequencing of the bacSJ2-8 gene enabled the determination of the primary structure of a bacteriocin BacSJ. The production and functional expression of BacSJ in homologous and heterologous hosts suggest that bacSJ2-8 and bacSJ2-8i together with the genes encoding the ABC transporter and accessory protein are the minimal requirement for the production of BacSJ. Biochemical and genetic analyses showed that BacSJ belongs to the class II bacteriocins. The shuttle cloning vector pA13 could be used as a tool for genetic manipulations in lactobacilli and lactococci