scholarly journals Physiological characters of psychrotolerant bacteria in a eutrophic bottom environment

1970 ◽  
Vol 20 (1) ◽  
pp. 49-56
Author(s):  
Md Abdul Karim ◽  
Kimio Fukami

An investigation for the isolation and identification of psychrotolerant bacteria from eutrophic bottom environment showed average temperature during winter and summer was 8 and 26°C, respectively. Six bacterial isolates were characterized in details and identified as Deleya halophila, Chromohalobacter marismortui, Erythrobacter longus, Pseudomonas perfectomarina, Marinobacter hydrocarbonoclasticus, Alteromonas undina. All isolates grew well at wide range of temperature between 5 and 30ºC and considered as psychrotolerant.Key words: Psychrotolerant bacteria; Eutrophic environmentDOI: http://dx.doi.org/10.3329/dujbs.v20i1.8837Dhaka Univ. J. Biol. Sci. 20(1): 49-56, 2011 (January)

Author(s):  
Sudha Sree

Abstract: Polysaccharides are important potent molecules with their structural and compositional complexity which led to wide range of applications in various industries. The exopolysaccharides of microbial origin are released in response to extreme environmental conditions for the purpose of survival. The present study focuses on the isolation of exopolysaccharide producing bacteria from the soil sample and oil contaminated soil sample. Screening for the EPS production by the isolates is determined by the dry weight determination of precipitates of EPS and quantitative estimation of glucose content of EPS by PhenolSulphuric acid method. In the present study, out of 5 bacterial isolates isolated on screening, Lactobacillus sps and Pseudomonas sps. isolates produced the precipitates of EPS whose dry weight was determined to be 0.09g and 0.17g respectively. Further, glucose concentration of EPS was quantitatively determined. The glucose content of Lactobacillus sps. isolate was 0.1125mg/ml and Pseudomonas sps. isolate is 0.2875mg/ml. The EPS producing isolates were further grown in the presence of carbon sources like Glucose, Lactose, Maltose and Sucrose to determine the best utilizable carbon for their growth. The most utilizable carbon source for maximum growth of EPS producing isolates was determined to be sucrose with 2% concentration. All the 5 bacterial isolates were screened for their ability of antibiotic resistance. The EPS producing isolates, Lactobacillus sps, Pseudomonas sps were found to be resistant towards all the antimicrobial agents owing to the presence of EPS protective layer around their cell wall than non-EPS producing isolates. Keywords: Exopolysaccharide, Screening, Carbon sources, Antibiotic resistance.


bionature ◽  
2018 ◽  
Vol 18 (2) ◽  
Author(s):  
Ulfia Nurul Khikmah ◽  
Muhson Isroni Isroni ◽  
Anisa Maulidiya

Abstract. The emphasis on the growth of Phytophthora palmivora was important in order to reduce Pod Rot Disease of cacao (Theobrorna cacao L.) which could harm agriculture sector. Some bacteria had chitinolytic enzyme activity that is potentially used as an antifungal against Phytophthora palmivora, because the cell wall of the fungi composed of chitin. The purpose of this research was to know chitinolytic bacteria from Perna viridis shell which had higher activity of chitinase enzyme, the amount of chitinase enzyme activity of each selected isolate, and to know the effect of chitinolytic bacterial isolates from Perna viridis shell to reduce the growth of Phytophthora palmivora. The bacteria were isolated from Perna viridis shell at Depok Beach, Kretek, Bantul, Yogyakarta. This research was an explorative research which include bacterial characterization and experimental research which include antagonistic test of chitinolytic bacteria against Phytophthora palmivora. The chitinolytic bacteria was isolated using selective chitin agar medium by pour plate method and then screening the isolates that had chitinase enzyme activity by measuring the enzyme activity of each bacterial isolates by spectrophotometric method. Selected bacterial isolates were characterized by macroscopic, microscopic and physiological characters. The bacteria that had been selected tested for their ability to reduce the growth of Phytophthora palmivora by Kirby Bauer modification method. The result showed that there were 10 isolates that had chitinase enzyme activity which two selected isolates had the higher chitinase enzyme activity. There were 7D and 6B isolates. The isolate 7D had 1,258 u/ml chitinase enzyme activity and isolate 6B had 1,212 u/ml chitinase enzyme activity. The result of chitinolytic bacterial antagonist test on Phytophthora palmivora growth showed that both bacterial isolates were potential to antifungal Phytophthora palmivora and showed a real effect in inhibiting the growth of Phytophthora palmivora with significance value < 0,05.Keywords: Chitinolytic Bacteria, Perna viridis, Phytophthora palmivora


2021 ◽  
Vol 4 (2) ◽  
pp. e126
Author(s):  
Iyabo Victoria Olatubi ◽  
Olukemi Aromolaran ◽  
Samuel Tolani Joseph ◽  
Oluwafeyikemi Ajoke Adeleke

The emerging field of forensic biology has attempted to solve certain problems encountered when estimating post-mortem interval (PMI) by using predictable changes in the microbial and arthropod community structure. Pig (Sus scrofa) carcasses are widely used as animal models in clinical human studies. The objective of this study was to identify bacteria from the skin surface of pig carcass for possible use in forensic investigation. Three pigs (a suitable human substitute) were collected from a local farm and killed by suffocation and further place in a bush land for decomposition. 24hours later skin samples were collected and transported to the laboratory for the isolation of bacteria using standard pour plate techniques and identified using Bergey’s manual of systemic bacteriology. The experiment was conducted in February 2019 during the dry season of the year with an average temperature of 23.50c and relative humidity of 60.8% A total of fourteen (14) isolates were gotten from the pig carcass samples out of which four (4) were Gram-positive bacteria and the remaining ten (10) were Gram-negative. Staphylococcus spp. (28.6%) was the most abundant while Salmonella sp., Serratia sp., Klebsiella sp., Citrobacter sp. and Proteus sp. occurred at 14.3% each. This study focus on the type of bacteria communities during a decomposition process which will help provide baseline information in the application of forensic biology to determination of nature of death, abuse or neglect.


2019 ◽  
Vol 4 (1) ◽  
pp. 79-88
Author(s):  
Evi Octaviany ◽  
Suharjono Suharjono ◽  
Irfan Mustafa

A commercial saponin as biosurfactant can reduce the surface tension of water and increase of hydrocarbon degradation. However, this saponin can be toxic to some hydrocarbonoclastic bac-teria. This study aimed to obtain bacterial isolates that were tolerant and incapable to degrade saponin, and to identify them based on 16S rDNA sequence. Bacteria were isolated from petroleum contaminated soil in Wonocolo Village, Bojonegoro Regency, East Java, Indonesia. The soil samples were acclimated using Bushnell-Haas (BH) broth with 0.5% crude oil at room temperature for 3 weeks. The culture was spread onto BH agar incubated at 30°C for 7 days. The first screened, isolates were grown in nutrient broth with addition of sap-onin 0%, 8%, and 12% (v/v) then incubated at 30°C for three days. The bacterial cell density was measured using a spectrophotometer. Second screened, the isolates were grown on BH broth with addition of 0.5% saponin as a sole carbon source, and their cell densities were measured. The selected isolates were identified based on 16S rDNA sequences. Among 34 bacterial isolates, nine isolates were tol-erant to 12% saponin. Three bacterial isolates IHT1.3, IHT1.5, and IHT3.24 tolerant to high concentration of saponin and did not use this substance as growth nutrition. The IHT1.3, IHT1.5, and IHT3.24 isolates were identified as Ochrobactrum pseudogrignonense (99% similarity), Pseudomonas mendocina (99%), and Ochrobactrum pi-tuitosum; (97%), respectively. Those three selected isolates are good candidates as hydrocarbon-degrading bacteria to bioremediation of soil contaminated crude oil. However, the combined activity of bacteria and saponin to degrade hydrocarbon needs further study. 


Viruses ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2275
Author(s):  
Yanxi Liu ◽  
Mengjiao Liu ◽  
Ran Hu ◽  
Jun Bai ◽  
Xiaoqing He ◽  
...  

Bacteriophages are viruses that specifically infect target bacteria. Recently, bacteriophages have been considered potential biological control agents for bacterial pathogens due to their host specificity. Pseudomonas syringae pv. actinidiae (Psa) is a reemerging pathogen that causes bacterial canker of kiwifruit (Actinidia sp.). The economic impact of this pest and the development of resistance to antibiotics and copper sprays in Psa and other pathovars have led to investigation of alternative management strategies. Phage therapy may be a useful alternative to conventional treatments for controlling Psa infections. Although the efficacy of bacteriophage φ6 was evaluated for the control of Psa, the characteristics of other DNA bacteriophages infecting Psa remain unclear. In this study, the PHB09 lytic bacteriophage specific to Psa was isolated from kiwifruit orchard soil. Extensive host range testing using Psa isolated from kiwifruit orchards and other Pseudomonas strains showed PHB09 has a narrow host range. It remained stable over a wide range of temperatures (4–50 °C) and pH values (pH 3–11) and maintained stability for 50 min under ultraviolet irradiation. Complete genome sequence analysis indicated PHB09 might belong to a new myovirus genus in Caudoviricetes. Its genome contains a total of 94,844 bp and 186 predicted genes associated with phage structure, packaging, host lysis, DNA manipulation, transcription, and additional functions. The isolation and identification of PHB09 enrich the research on Pseudomonas phages and provide a promising biocontrol agent against kiwifruit bacterial canker.


Author(s):  
O. Aleruchi ◽  
O. Obire

This investigation focuses on molecular identification of antibiotic resistant bacteria isolated from petroleum producing vicinity using 16S rRNA sequencing based technique. The bacterial 16s rRNA gene sequences were amplified using polymerase chain reaction, sequenced,  characterized and compared by using primers which has been compared to national center for biotechnology information (NCBI) sequence database. The presence of the plasmid mediated antibiotic resistance determinants CTX-M and QNRB genes in the bacterial isolates were analyzed. A total of four bacterial isolates that were resistant to all the antibiotic agents used were identified molecularly. The BLAST results showed 100 % similarity and phylogenetic study indicated that the genes were evolutionarily related to Morganella morganii, Pseudomonas xiamenensis, Chryseobacterium cucumeris and Staphylococcus sp., respectively. The genes obtained were submitted to the NCBI gene bank and were assigned accession number; MN094330, MN094331, MN094332 and MN094333, respectively. CTX-M and QNRB genes were however absent in the bacterial isolates. The result identified some peculiar abilities of the bacterial isolates to be resistant to antibiotics and suggests a correlation with resistance and hydrocarbon utilizing bacteria. The level of resistance could be as a result of the disinfection process during wastewater treatment procedure or the same adaptive mechanisms possessed by the isolates to control the hydrocarbon concentration in their cell. The study also clearly indicates that these wastewaters, when discharged into the environment directly may pose a risk for the spread of antibiotic resistant bacteria.


Plant Disease ◽  
2003 ◽  
Vol 87 (7) ◽  
pp. 832-840 ◽  
Author(s):  
O. Erincik ◽  
L. V. Madden ◽  
D. C. Ferree ◽  
M. A. Ellis

In 1998 and 1999, controlled-environment studies were conducted in growth chambers to determine the temperature and wetness-duration parameters required for leaf and cane infection of grape by Phomopsis viticola. Greenhouse-grown ‘Catawba’ (Vitis labrusca) and ‘Seyval’ (French hybrid) grapes were inoculated with P. viticola and incubated at constant temperatures of 5, 10, 15, 20, 25, 30, and 35°C and at wetness durations of 5, 10, 15, and 20 h for each temperature. Data from each cultivar were analyzed by nonlinear regression analysis to determine the relationship between disease severity and temperature and wetness duration. A generalized form of the Analytis Beta model was found to provide the best fit to the data. Disease severity on leaves and canes increased with increasing wetness duration at most temperatures. Minimum and maximum temperatures for infection were around 5 and 35.5°C, respectively. Optimum temperatures for leaf and cane infection were between 16 and 20°C. In the 2000 and 2001 growing seasons, the generalized Beta model was validated in ‘Catawba’ and ‘Seyval’ vineyards by inoculating vines during natural rain events. Average temperature and hours of wetness for each event and inoculation were recorded and used in the model equation to predict disease severity on leaves and internodes. Correlation coefficients between observed disease severities following field inoculations and predicted disease severities for both cultivars were between 0.71 and 0.81 and always significant (P < 0.01). These results indicate that the model reliably predicted leaf and cane infection on both cultivars over a wide range of wetness durations and temperatures. The model may be useful in developing disease-forecasting systems for Phomopsis cane and leaf spot on grapes.


1970 ◽  
Vol 8 (1) ◽  
pp. 05-10 ◽  
Author(s):  
J Akhter ◽  
MT Hossain ◽  
MT Islam ◽  
MP Siddique ◽  
MA Islam

The research work was conducted to isolate and identify the microflora from apparently healthy caged parrots. A total of 45 samples (oral swabs, cloacal swabs and feces) were collected from five types of caged parrots (Gray cockatiels, Rose ringed parakeet, Alexandriane parakeet, Red breast parakeet and Blossom headed parakeet) of Dhaka Zoo during the period from April to August 2009. The samples were cultured on different bacteriological media and the bacteria were identified by their cultural and biochemical properties. All the isolates were allowed for antibiogram study. The bacteria isolated in this study from different types of caged parrots were E. coli (64.44%), Salmonella spp. (46.67%), Staphylococcus spp. (46.67%), Pasteurella spp. (33.33%), Proteus spp. (6.67%) and some unidentified Gram-positive and Gram-negative bacteria. Of these isolates, E. coli was the most frequent isolate. The frequency of Gram-negative bacteria was higher in this study. The percentage of bacterial isolates recovered from each type of parrots was almost similar. Irrespective of types of parrots, the higher percentage of different bacteria was isolated from cloacal swab (77.78%) followed by feces (75.56%). The 68.89% isolates were recovered from oral swab. All the suspected isolates of Salmonella spp. were confirmed by slide agglutination test using Salmonella polyvalent ‘O’ antiserum. Among the 21 Salmonella spp. isolated in this study, 4 (19.05%) isolates were identified as S. Pullorum when tested with specific antisera against S. Pullorum. The results of antibiotic sensitivity tests revealed that ampicillin and amoxicillin were completely resistant to E. coli and Pasteurella spp.; ampicillin to Proteus spp.; and furazolidone to Salmonella spp. and Pasteurella spp. However, the antibiotics of fluoroquinolone group such as ciprofloxacin, norfloxacin and enrofloxacin showed moderate to high sensitivity against almost all the bacterial isolates. Of these, ciprofloxacin was found to be consistently highly sensitive to all the bacterial isolates. DOI = 10.3329/bjvm.v8i1.8349 Bangl. J. Vet. Med. (2010). 8(1): 05-10


2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Joseph Gichuhi ◽  
Fathiya Khamis ◽  
Johnnie Van den Berg ◽  
Samira Mohamed ◽  
Sunday Ekesi ◽  
...  

Abstract Background Symbiotic interactions between insects and bacteria have been associated with a vast variety of physiological, ecological and evolutionary consequences for the host. A wide range of bacterial communities have been found in association with the oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), an important pest of cultivated fruit in most regions of the world. We evaluated the diversity of gut bacteria in B. dorsalis specimens from several populations in Kenya and investigated the roles of individual bacterial isolates in the development of axenic (germ-free) B. dorsalis fly lines and their responses to the entomopathogenic fungus, Metarhizium anisopliae. Results We sequenced 16S rRNA to evaluate microbiomes and coupled this with bacterial culturing. Bacterial isolates were mono-associated with axenic B. dorsalis embryos. The shortest embryonic development period was recorded in flies with an intact gut microbiome while the longest period was recorded in axenic fly lines. Similarly, larval development was shortest in flies with an intact gut microbiome, in addition to flies inoculated with Providencia alcalifaciens. Adult B. dorsalis flies emerging from embryos that had been mono-associated with a strain of Lactococcus lactis had decreased survival when challenged with a standard dosage of M. anisopliae ICIPE69 conidia. However, there were no differences in survival between the germ-free lines and flies with an intact microbiome. Conclusions These findings will contribute to the selection of probiotics used in artificial diets for B. dorsalis rearing and the development of improved integrated pest management strategies based on entomopathogenic fungi.


Author(s):  
Hasan A. Khalaf ◽  
Ibrahim S. Abbas ◽  
Amani A. Tawfeeq ◽  
Monther F. Mahdi

Objective: Plantago lanceoleta L. (ribwort plantain) is one of the important medicinal herbs which is widespread fortune available in Iraq, that have a wide range of medicinal properties. The aim of this work was to determine, isolate and identify verbascoside and aucubin in Iraqi P. lanceoleta L. by using different chromatographic and spectrometric methods. Methods: Verbascoside and aucubin were isolated and quantified by preparative TLC, and then they were determined by the high-performance thin-layer chromatography (HPTLC) fingerprinting. Aucubin and catalpol in the plant extract were analyzed by liquid chromatography-mass spectrometry (LC-MS); aucubin and verbascoside that isolated from the plant sample were examined by fourier-transform infrared spectroscopy (FT-IR) and LC-MS, respectively. Results: The result showed that the Iraqi P. lanceoleta L. contains 1.74 percent (verbascoside) and 0.24 percent (aucubin) of dry powdered leaves. Each TLC-isolated compound showed a single spot on the HPTLC plate, which give an idea about the purity of the isolated compound. Aucubin (with catalpol) and verbascoside both are detected by LC-MS in different ionization mode. Many functional groups were identified in the TLC-isolated aucubin by FT-IR. Conclusion: The Iraqi P. lanceoleta L. showed a high content of verbasoside, and it is a very rich source for this compound, which can be easily isolated by TLC and subjected to many pharmacological studies. The extract of the young leaves of this plant gave a little amount of aucubin, and it is easy to obtain a higher content from the older leaves.


Sign in / Sign up

Export Citation Format

Share Document