Physiological and Morphological Changes Induced by Nutrient Limitation of Pseudomonas fluorescens 378 in Continuous Culture
Physiological and Morphological Changes Induced by Nutrient Limitation of Pseudomonas fluorescens 378 in Continuous Culture
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连续培养中荧光假单胞菌378营养限制引起的生理和形态变化
DOI：
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发表时间：
1990
影响因子：
4.4
通讯作者：
C. Weibull
中科院分区：
文献类型：
--
作者：
A. Persson;G. Molin;C. Weibull
在连续培养中研究荧光假单胞菌378，稀释率为0.05或0.15 h−1，并在碳/能、氮、磷、铁（III）或氧的限制下。检测培养物的营养消耗、生物表面活性剂AP-6和脂肪酶的产生以及电子显微镜形态。在透射电镜下观察到细胞的形态特征为细胞溶解和质解，细胞内出现液泡，细胞核内出现颗粒，DNA凝固。生物表面活性剂和脂肪酶的产生在8 ~ 15次保留后失去，但在铁限制和低稀释率下，它们可以保持30次以上的保留。不同文化的人对营养物质的消耗量不同。每克（干重）消耗2.4至6.0克琥珀酸；在限磷条件下，其值最高。对氮的吸收主要在0.16 g/g（干重）左右，对磷的吸收在13 ~ 58 mg/g（干重）之间变化。限磷电池与其他限制电池相比，其磷消耗至少减少了50%。不同培养物的细胞形态不同。在较高的稀释率下，高达25%的细胞裂解发生。质解的频率在0 ~ 85%之间变化。65% ~ 100%的细胞可见核内颗粒。液泡多以低数量出现，但在磷或铁稀释率较低的条件下，液泡出现的频率增加到25% ~ 85%。在高稀释率下，DNA在30 - 70%的细胞中凝固。多变量数据分析表明，两种稀释率之间存在普遍差异；即，营养和形态特征在两种测试稀释率之间的差异大于不同限制之间的差异。低稀释率的培养物随时间变化更大；这在磷或铁的限制中尤其明显。数据分析还表明，在磷限制下，细胞内的质解或液泡与碳吸收增加之间存在相关性。
Pseudomonas fluorescens 378 was studied in continuous culture at a dilution rate of 0.05 or 0.15 h−1 and under a limitation of carbon/energy, nitrogen, phosphorus, iron(III), or oxygen. Cultures were examined for nutritional consumption, production of biosurfactant AP-6 and lipase, and electron microscopy morphology. Morphological features were lysis and plasmolysis of the cells, vacuoles in the cells, granules in cell nuclei, and DNA coagulation during transmission electron microscopy preparation. Biosurfactant and lipase production were lost after 8 to 15 retention times, but under iron limitation and at low dilution rate they were maintained for more than 30 retention times. Consumption of nutrients varied between different cultures. Between 2.4 and 6.0 g of succinic acid per g (dry weight) was consumed; the highest value was obtained under phosphorus limitation. The uptake of nitrogen was mostly about 0.16 g/g (dry weight), and that of phosphorus varied between 13 and 58 mg/g (dry weight). Phosphorus-limited cells reduced their phosphorus consumption by at least 50% compared with other limitations. Cell morphology varied among different cultures. Up to 25% cell lysis occurred at the higher dilution rate. The frequencies of plasmolysis varied between 0 and 85%. Granules in nuclei were found in 65 to 100% of the cells. Vacuoles appeared mostly in low numbers, but at the lower dilution rate under phosphorus or iron limitation the frequencies increased to between 25 and 85%. At high dilution rate, the DNA coagulated in 30 to 70% of the cells. Multivariate data analysis demonstrated a general difference between the two tested dilution rates; i.e., both nutritional and morphological features differed more between the two tested dilution rates than between the different limitations. Cultures at the lower dilution rate changed more with time; this was especially pronounced for phosphorus or iron limitation. The data analysis also showed a correlation between plasmolysis or vacuoles in the cells and an increased carbon uptake under phosphorus limitation.
影响因子：
2.9
作者：
SCHWYN, B;NEILANDS, JB
通讯作者：
NEILANDS, JB