Cationic liposomes are traditionally used for delivering macromolecules such as nucleic acids to mammalian and plant cells. This paper describes a novel simple and relatively inexpensive method for preparation of cationic liposomes using an ethanol injection/pressure extrusion method. The study also evaluated the utility of a colorimetric method for quantification of cationic liposomes. Binding of erythrosine dye to cationic liposomes resulted in a shift of the absorption maximum of the dye from 528nm to 549nm in a buffer at pH 4.25, allowing quantification of these vesicles. Colour development was completed in 5 to 10 minutes at room temperature, with only 10% decrease in absorbance observed in the following 2 hours. Divergent values were noted in the presence of interfering agents such as detergents and salts. The erythrosine method is sensitive down to 0.20 µg/mL of cationic lipid and is linear to 3.13 µg/mL. The erythrosine dye method for quantitation of cationic liposomes is valuable for the field of liposome technology. In addition, a relatively simple method for separation of nucleic acids complexed to cationic liposomes from unbound molecules is presented. This method utilises a Ficoll-based gradient centrifugation method. Laboratory-formulated liposomes were just as efficient in binding nucleic acids as commercially available types.
{"title":"Formulation and quality control of cationic liposomes","authors":"C. Dass","doi":"10.1071/SP01004","DOIUrl":"https://doi.org/10.1071/SP01004","url":null,"abstract":"Cationic liposomes are traditionally used for delivering macromolecules such as nucleic acids to mammalian and plant cells. This paper describes a novel simple and relatively inexpensive method for preparation of cationic liposomes using an ethanol injection/pressure extrusion method. The study also evaluated the utility of a colorimetric method for quantification of cationic liposomes. Binding of erythrosine dye to cationic liposomes resulted in a shift of the absorption maximum of the dye from 528nm to 549nm in a buffer at pH 4.25, allowing quantification of these vesicles. Colour development was completed in 5 to 10 minutes at room temperature, with only 10% decrease in absorbance observed in the following 2 hours. Divergent values were noted in the presence of interfering agents such as detergents and salts. The erythrosine method is sensitive down to 0.20 µg/mL of cationic lipid and is linear to 3.13 µg/mL. The erythrosine dye method for quantitation of cationic liposomes is valuable for the field of liposome technology. In addition, a relatively simple method for separation of nucleic acids complexed to cationic liposomes from unbound molecules is presented. This method utilises a Ficoll-based gradient centrifugation method. Laboratory-formulated liposomes were just as efficient in binding nucleic acids as commercially available types.","PeriodicalId":148381,"journal":{"name":"The South Pacific Journal of Natural and Applied Sciences","volume":"54 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133170553","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
P. Nunn, R. Thaman, L. Duffy, S. Finikaso, N. Ram, M. Swamy
A 14C date for a charcoal band near the base of the High (10 m) Terrace in the middle Sigatoka Valley (western Viti Levu Island, Fiji) shows that this terrace accumulated mostly within the past 4-5000 years showing it to be a Holocene rather than a Pleistocene (Last Interglacial) landform as previously thought. The charcoal band also indicates that there was extensive, perhaps catastrophic, burning of forests and perhaps an associated local extirpation/extinction of forest taxa. The notion that humans may have been responsible for the forest burning represented by this charcoal band is rejected on account of its age predating known human arrival by at least one thousand years. Attention is drawn to the contemporaneity of this charcoal band and those found in Bonatoa Bog (southeast Viti Levu Island) and in New Caledonia, some 1300 km southwest of Fiji, suggesting that catastrophic forest burning during this period may have been widespread and a regionwide response to a period of prolonged aridity 4500-5000 years ago, possibly associated with a unusually severe El Nino event.
在Sigatoka山谷中部(斐济Viti Levu岛西部)的高(10米)阶地底部附近的木炭带进行的14C测年表明，该阶地主要是在过去的4-5000年里积累的，这表明它是一个全新世，而不是之前认为的更新世(末次间冰期)地貌。木炭带也表明有广泛的，也许是灾难性的森林燃烧，也许与当地森林分类群的灭绝有关。人类可能对这条木炭带所代表的森林燃烧负责的观点被拒绝了，因为它的年龄比已知的人类到来至少早了一千年。值得注意的是，这一木炭带与在Bonatoa Bog (Viti Levu岛东南部)和新喀里多尼亚(斐济西南约1300公里)发现的木炭带的同年代性表明，这一时期的灾难性森林燃烧可能是广泛存在的，是对4500-5000年前长期干旱时期的区域性反应，可能与异常严重的厄尔尼诺事件有关。
{"title":"Age of a charcoal band in fluvial sediments, Keiyasi, Sigatoka Valley, Fiji: possible indicator of a severe drought throughout the Southwest Pacific 4500-5000 years ago","authors":"P. Nunn, R. Thaman, L. Duffy, S. Finikaso, N. Ram, M. Swamy","doi":"10.1071/SP01002","DOIUrl":"https://doi.org/10.1071/SP01002","url":null,"abstract":"A 14C date for a charcoal band near the base of the High (10 m) Terrace in the middle Sigatoka Valley (western Viti Levu Island, Fiji) shows that this terrace accumulated mostly within the past 4-5000 years showing it to be a Holocene rather than a Pleistocene (Last Interglacial) landform as previously thought. The charcoal band also indicates that there was extensive, perhaps catastrophic, burning of forests and perhaps an associated local extirpation/extinction of forest taxa. The notion that humans may have been responsible for the forest burning represented by this charcoal band is rejected on account of its age predating known human arrival by at least one thousand years. Attention is drawn to the contemporaneity of this charcoal band and those found in Bonatoa Bog (southeast Viti Levu Island) and in New Caledonia, some 1300 km southwest of Fiji, suggesting that catastrophic forest burning during this period may have been widespread and a regionwide response to a period of prolonged aridity 4500-5000 years ago, possibly associated with a unusually severe El Nino event.","PeriodicalId":148381,"journal":{"name":"The South Pacific Journal of Natural and Applied Sciences","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126739343","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
power output of 20 mW. A horn antenna (23 cm x 18 cm) was used at the transmitting end and a dish antenna (64 cm diameter) was used at the receiving end. The dish had a reflex waveguide feed. Behind the dish was mounted a Low Noise Broadband (LNB) converter, and the entire assembly could be rotated in the horizontal plane for the purpose of alignment. The LNB was connected to ICOM-R7100 receiver. The receiver was operated in the wideband FM mode and with the automatic frequency control on. This compensated for any frequency drift in the transmitted frequency. The clear-sky signal-to-noise ratio of the beacon at the receiver was determined by comparing the signal strengths of the ICOM receiver with and without those of the transmitter signal and this was about 26 dB. Measurements were carried out for several days that
输出功率20mw。发射端采用23 cm × 18 cm的喇叭天线，接收端采用直径64 cm的碟形天线。这个碟子有一个反射波导馈源。在碟子后面安装了一个低噪声宽带(LNB)转换器，整个组件可以在水平面上旋转以对准。LNB连接ICOM-R7100接收机。接收机在宽带调频模式下工作，并开启自动频率控制。这补偿了发射频率中的任何频率漂移。通过比较ICOM接收机与无发射信号的信号强度，确定接收机信标的晴空信噪比，约为26 dB。测量进行了好几天
{"title":"Effect of thunderclouds on space wave propagation at 10 GHz","authors":"V. Ramachandran, N. Nand, R. Northcott","doi":"10.1071/SP01009","DOIUrl":"https://doi.org/10.1071/SP01009","url":null,"abstract":"power output of 20 mW. A horn antenna (23 cm x 18 cm) was used at the transmitting end and a dish antenna (64 cm diameter) was used at the receiving end. The dish had a reflex waveguide feed. Behind the dish was mounted a Low Noise Broadband (LNB) converter, and the entire assembly could be rotated in the horizontal plane for the purpose of alignment. The LNB was connected to ICOM-R7100 receiver. The receiver was operated in the wideband FM mode and with the automatic frequency control on. This compensated for any frequency drift in the transmitted frequency. The clear-sky signal-to-noise ratio of the beacon at the receiver was determined by comparing the signal strengths of the ICOM receiver with and without those of the transmitter signal and this was about 26 dB. Measurements were carried out for several days that","PeriodicalId":148381,"journal":{"name":"The South Pacific Journal of Natural and Applied Sciences","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126371423","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
β-Damascenone, a potent aroma component of in a variety of grapes and wines, has a sensory threshold of approximately 2ng/L in water. This C13 norisoprenoid ketone is principally generated from hydrolyzable precursors, which was glycosidically bound. Isolation of β-damascenone-yielding precursors from Cabernet Sauvignon grape skins using C18 reversed phase chromatography followed by droplet countercurrent chromatography yielded multiple chromatographically distinguishable precursor fractions. The existence of multiple precursors was further evident from the varying ratios of 3-hydroxy- β-damascone (the by-product): β-damascenone generated upon acid hydrolysis of the chromatographically distinguishable precursor fractions.
{"title":"β-Damascenone-yielding precursor(s) from Cabernet Sauvignon grapes","authors":"M. Naiker","doi":"10.1071/SP01003","DOIUrl":"https://doi.org/10.1071/SP01003","url":null,"abstract":"β-Damascenone, a potent aroma component of in a variety of grapes and wines, has a sensory threshold of approximately 2ng/L in water. This C13 norisoprenoid ketone is principally generated from hydrolyzable precursors, which was glycosidically bound. Isolation of β-damascenone-yielding precursors from Cabernet Sauvignon grape skins using C18 reversed phase chromatography followed by droplet countercurrent chromatography yielded multiple chromatographically distinguishable precursor fractions. The existence of multiple precursors was further evident from the varying ratios of 3-hydroxy- β-damascone (the by-product): β-damascenone generated upon acid hydrolysis of the chromatographically distinguishable precursor fractions.","PeriodicalId":148381,"journal":{"name":"The South Pacific Journal of Natural and Applied Sciences","volume":"327 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132851505","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cycas seemannii occurs in several habitats in Vanuatu, New Caledonia, Fiji and Tonga, but is mostly coastal. Growth rates are about 5-15cm.yr-1 and sex ratios observed were almost neutral. Mechanisms to survive in adverse environments are discussed. Female plants were found to produce, on average, longer leaves with more leaflets than male plants. Larvae of an unidentified moth, which are parasitised by at least two species of wasps, mine the leaflets of C. seemannii. Reproduction occurs mainly by seeds and bulbils. Wind appears to be the major pollination agent. Seed dispersal, other than oceanic, appears to be inefficient.
{"title":"Notes on the Natural History of Cycas seemannii (Cycadaceae)","authors":"G. Keppel","doi":"10.1071/SP01007","DOIUrl":"https://doi.org/10.1071/SP01007","url":null,"abstract":"Cycas seemannii occurs in several habitats in Vanuatu, New Caledonia, Fiji and Tonga, but is mostly coastal. Growth rates are about 5-15cm.yr-1 and sex ratios observed were almost neutral. Mechanisms to survive in adverse environments are discussed. Female plants were found to produce, on average, longer leaves with more leaflets than male plants. Larvae of an unidentified moth, which are parasitised by at least two species of wasps, mine the leaflets of C. seemannii. Reproduction occurs mainly by seeds and bulbils. Wind appears to be the major pollination agent. Seed dispersal, other than oceanic, appears to be inefficient.","PeriodicalId":148381,"journal":{"name":"The South Pacific Journal of Natural and Applied Sciences","volume":"60 11","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133072532","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
There is evidence that the soil health in Taveuni, Fiji is deteriorating over time threatening livelihoods of taro producers. The present study was conducted to understand the soil nutrient management practices followed by taro farmers in Taveuni. The study revealed that the farmers in Taveuni use various organic and chemical fertilizers and various other soil fertility management practices such as mulching, crop rotation with legumes, yagona and agroforestry. The quantity of nitrogen, phosphorous and potash (NPK) applied to taro crop on different types of soils was meager. The study further revealed that there was imbalanced and insufficient use of chemical fertilizers and organic sources of soil nutrients. The main cause of low use of fertilizers was that the farmers in Taveuni do not know the fertility status of their farms as no soil testing was ever done and majority of them are also not fully aware of various low-cost organic methods of maintaining soil fertility of farms.
{"title":"Evaluation of soil nutrient management practices of taro farmers in Taveuni, Fiji","authors":"S. Nisha, S. Prasad, J. P. Bhati","doi":"10.1071/SP14010","DOIUrl":"https://doi.org/10.1071/SP14010","url":null,"abstract":"There is evidence that the soil health in Taveuni, Fiji is deteriorating over time threatening livelihoods of taro producers. The present study was conducted to understand the soil nutrient management practices followed by taro farmers in Taveuni. The study revealed that the farmers in Taveuni use various organic and chemical fertilizers and various other soil fertility management practices such as mulching, crop rotation with legumes, yagona and agroforestry. The quantity of nitrogen, phosphorous and potash (NPK) applied to taro crop on different types of soils was meager. The study further revealed that there was imbalanced and insufficient use of chemical fertilizers and organic sources of soil nutrients. The main cause of low use of fertilizers was that the farmers in Taveuni do not know the fertility status of their farms as no soil testing was ever done and majority of them are also not fully aware of various low-cost organic methods of maintaining soil fertility of farms.","PeriodicalId":148381,"journal":{"name":"The South Pacific Journal of Natural and Applied Sciences","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128790560","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Solution cast blends of poly(e-caprolactone) [PCL] and poly(vinyl formal) [PVF] from dichloromethane was investigated for miscibility by Differential Scanning Calorimetry [DSC], Fourier Transform Infrared Spectroscopy [FTIR] and optical microscopy. Melting (Tm) and crystallization (Tc) temperatures were for the PCL fraction while the glass transition temperature (Tg) was for PVF fraction in the blends. Blends with 20 wt% and less PCL showed a depression in Tm and Tc. Depression in Tc indicated that during the non-isothermal crystallization process, the presence of PVF decreased the PCL segments migrating to the crystallite-melt interface thus reducing the nucleation rate, growth rate and the thickness of the lamella resulting in a depressed Tm. Crystallinity (Xc) decreased gradually with decreasing content of PCL in the blend and was due to the dilution of PCL by PVF. A depressed Tg was observed for 10 wt% PCL blend and remained the same for all other blend compositions. These observations suggested that this blend system has very low degree of miscibility. The degree of miscibility increased at low polyester concentration. FTIR spectra of the blends with low polyester concentrations showed changes in the C=O, O-H and C-O-C regions in the blended PVF and PCL spectra. Optical microscopy showed phase separation in the melt and in the PCL spherulites.
{"title":"Miscibility, melting and crystallization of poly(ε-caprolactone) and poly (vinyl formal) blend","authors":"D. Rohindra, J. R. Khurma","doi":"10.1071/SP07009","DOIUrl":"https://doi.org/10.1071/SP07009","url":null,"abstract":"Solution cast blends of poly(e-caprolactone) [PCL] and poly(vinyl formal) [PVF] from dichloromethane was investigated for miscibility by Differential Scanning Calorimetry [DSC], Fourier Transform Infrared Spectroscopy [FTIR] and optical microscopy. Melting (Tm) and crystallization (Tc) temperatures were for the PCL fraction while the glass transition temperature (Tg) was for PVF fraction in the blends. Blends with 20 wt% and less PCL showed a depression in Tm and Tc. Depression in Tc indicated that during the non-isothermal crystallization process, the presence of PVF decreased the PCL segments migrating to the crystallite-melt interface thus reducing the nucleation rate, growth rate and the thickness of the lamella resulting in a depressed Tm. Crystallinity (Xc) decreased gradually with decreasing content of PCL in the blend and was due to the dilution of PCL by PVF. A depressed Tg was observed for 10 wt% PCL blend and remained the same for all other blend compositions. These observations suggested that this blend system has very low degree of miscibility. The degree of miscibility increased at low polyester concentration. FTIR spectra of the blends with low polyester concentrations showed changes in the C=O, O-H and C-O-C regions in the blended PVF and PCL spectra. Optical microscopy showed phase separation in the melt and in the PCL spherulites.","PeriodicalId":148381,"journal":{"name":"The South Pacific Journal of Natural and Applied Sciences","volume":"61 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114305889","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Photosynthetic rate and biochemical composition total chlorophyll (TC), total soluble protein (TSP) and total soluble carbohydrates (TSC) were determined for Ulva flexuosa, a green marine algae collected from Nasese, Lami and Laucala Beach areas in Suva, Fiji Islands. Ulva flexuosa from Laucala Beach area had the highest photosynthetic rates, TC and TSP content, while algae from Nasese area had the highest amount of TSC. Algae from Lami area had the lowest amount of photosynthesis rate, TC, TSP and TSC. High photosynthetic rate and biochemical content were mainly due to the presence of high levels of nitrogen in the area. Algae thrived in Laucala Beach and Nasese area where nitrogen content was high. Low photosynthetic rate and biochemical composition were recorded in algae from the Lami area, which was apparently the most polluted area. It appeared that conditions in Lami area were intolerable to U. flexuosa. Algae collected from the three sites differed in the measured parameters with respect to the differences in the pH, temperature and nitrogen levels indicating that physiological responses of algae could be used as indicators to monitor the environmental quality of the intertidal zones.
{"title":"Photosynthetic rate and biochemical composition of green algae Ulva flexuosa (Wulfen) J. Agardh as potential indicators of environmental stress in the intertidal zones","authors":"R. Prakash, A. Jokhan","doi":"10.1071/SP12004","DOIUrl":"https://doi.org/10.1071/SP12004","url":null,"abstract":"Photosynthetic rate and biochemical composition total chlorophyll (TC), total soluble protein (TSP) and total soluble carbohydrates (TSC) were determined for Ulva flexuosa, a green marine algae collected from Nasese, Lami and Laucala Beach areas in Suva, Fiji Islands. Ulva flexuosa from Laucala Beach area had the highest photosynthetic rates, TC and TSP content, while algae from Nasese area had the highest amount of TSC. Algae from Lami area had the lowest amount of photosynthesis rate, TC, TSP and TSC. High photosynthetic rate and biochemical content were mainly due to the presence of high levels of nitrogen in the area. Algae thrived in Laucala Beach and Nasese area where nitrogen content was high. Low photosynthetic rate and biochemical composition were recorded in algae from the Lami area, which was apparently the most polluted area. It appeared that conditions in Lami area were intolerable to U. flexuosa. Algae collected from the three sites differed in the measured parameters with respect to the differences in the pH, temperature and nitrogen levels indicating that physiological responses of algae could be used as indicators to monitor the environmental quality of the intertidal zones.","PeriodicalId":148381,"journal":{"name":"The South Pacific Journal of Natural and Applied Sciences","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130193349","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The application of synthetic phosphorous fertilizer is a routine agricultural practice. However, in nature in the soil, several phosphate-solubilising microbes (PSM) have been identified in the rhizosphere, and are of significance in organic farming. Two major PSM are Rhizobium sp. and Aspergillus sp. that has been identified to have the potential to establish as biofilms in the soil root-zone environment. As the fungi are capable of solubilising both organic and rock phosphates, co-inoculation of these two microbes will enhance the availability of available phosphates to plants and in turn will reduce the requirement of synthetic fertilizers. The present study aims to evaluate the survivability of these two organisms in vitro conditions as co-inoculants. Aspergillus sp. seemed to be more synergistic or associative in growth with the rhizobial strains, and this organism is known well as a rigorous PSM. The effect of rhizobial toxins on the isolated fungal strains and the fungal toxins on the isolated rhizobial strains were tested in this study. Results show that Aspergillus flavus 2 and Rhizobium sp. K 1 strains were found to be highly antagonistic and will be eliminated for further studies. Nevertheless, synergism was found to be highly variable amongst not only within rhizobial strains, but also amongst the isolated fungal strains.
{"title":"Aspergilli and rhizobia are better co-inoculants as biofertilizers","authors":"D. James, R. Predeepa","doi":"10.1071/SP11002","DOIUrl":"https://doi.org/10.1071/SP11002","url":null,"abstract":"The application of synthetic phosphorous fertilizer is a routine agricultural practice. However, in nature in the soil, several phosphate-solubilising microbes (PSM) have been identified in the rhizosphere, and are of significance in organic farming. Two major PSM are Rhizobium sp. and Aspergillus sp. that has been identified to have the potential to establish as biofilms in the soil root-zone environment. As the fungi are capable of solubilising both organic and rock phosphates, co-inoculation of these two microbes will enhance the availability of available phosphates to plants and in turn will reduce the requirement of synthetic fertilizers. The present study aims to evaluate the survivability of these two organisms in vitro conditions as co-inoculants. Aspergillus sp. seemed to be more synergistic or associative in growth with the rhizobial strains, and this organism is known well as a rigorous PSM. The effect of rhizobial toxins on the isolated fungal strains and the fungal toxins on the isolated rhizobial strains were tested in this study. Results show that Aspergillus flavus 2 and Rhizobium sp. K 1 strains were found to be highly antagonistic and will be eliminated for further studies. Nevertheless, synergism was found to be highly variable amongst not only within rhizobial strains, but also amongst the isolated fungal strains.","PeriodicalId":148381,"journal":{"name":"The South Pacific Journal of Natural and Applied Sciences","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134644590","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The development of multiple metal/antibiotic resist ances among the bacterial population causes a poten tial risk to human health. Metal contamination in natura l environments could have an important role in the maintenance and proliferation of antibiotic resista nce. In the present study, a total of 46 heterotrop hic bacterial isolates from metal contaminated soil were tested f or their sensitivity to 10 widely used antibiotics such as ampicillin, erythromycin, gentamicin, nalidixic aci d, penicillin, amikacin, lincomycin, novobiocin, va ncomycin and tetracycline. Metal tolerant ability of these iagainst five heavy metals such as lead, zin c, copper, cadmium and nickel were also determined. The result s revealed that most of the bacterial isolates were resistant to one or more heavy metals/ antibiotics against wh ich they are tested. Tolerance to heavy metal showe d the following pattern; lead > zinc > nickel > copper > cadmium. Resistance to ampicillin (73.91%), penicillin (60.8%), lincomycin (43.47%) and nalidixic acid (21 .73%) were encountered frequently. None of the isol ates were resistant to amikacin, while resistance to gen tamicin and tetracycline were low (2.17%). Out of the 46 bacterial isolates, 36 isolates showed multiple met al and antibiotic resistances. Isolate LOC 10 showe d significantly high tolerance (100-300ug/mL) to all the metals and was resistant to 6 antibiotics.
{"title":"Heavy metal tolerance and multiple drug resistance of heterotrophic bacterial isolates from metal contaminated soil","authors":"M. Krishna, R. Varghese, A. Hatha","doi":"10.1071/SP12006","DOIUrl":"https://doi.org/10.1071/SP12006","url":null,"abstract":"The development of multiple metal/antibiotic resist ances among the bacterial population causes a poten tial risk to human health. Metal contamination in natura l environments could have an important role in the maintenance and proliferation of antibiotic resista nce. In the present study, a total of 46 heterotrop hic bacterial isolates from metal contaminated soil were tested f or their sensitivity to 10 widely used antibiotics such as ampicillin, erythromycin, gentamicin, nalidixic aci d, penicillin, amikacin, lincomycin, novobiocin, va ncomycin and tetracycline. Metal tolerant ability of these iagainst five heavy metals such as lead, zin c, copper, cadmium and nickel were also determined. The result s revealed that most of the bacterial isolates were resistant to one or more heavy metals/ antibiotics against wh ich they are tested. Tolerance to heavy metal showe d the following pattern; lead > zinc > nickel > copper > cadmium. Resistance to ampicillin (73.91%), penicillin (60.8%), lincomycin (43.47%) and nalidixic acid (21 .73%) were encountered frequently. None of the isol ates were resistant to amikacin, while resistance to gen tamicin and tetracycline were low (2.17%). Out of the 46 bacterial isolates, 36 isolates showed multiple met al and antibiotic resistances. Isolate LOC 10 showe d significantly high tolerance (100-300ug/mL) to all the metals and was resistant to 6 antibiotics.","PeriodicalId":148381,"journal":{"name":"The South Pacific Journal of Natural and Applied Sciences","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131695611","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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