A growth initiation factor involved in magnesium utilization by certain soil bacteria

1984 ◽  
Vol 30 (6) ◽  
pp. 824-829 ◽  
Author(s):  
L. E. Casida Jr.
Keyword(s):  
Initial Rate ◽  
Azotobacter Vinelandii ◽  
Micrococcus Luteus ◽  
Initiation Factor ◽  
Dual Culture ◽  
Heat Labile ◽  
Culture Filtrates ◽  
Dual Cultures ◽  
Growth Initiation ◽  
Ensifer Adhaerens

Actinomyces humiferus was shown to require relatively high levels of magnesium for growth initiation. This growth initiation response to magnesium was graded. Live, but not heat-killed, cultures of Azotobacter vinelandii cells could replace at least a part of the magnesium requirement when Act. humiferus and Azo. vinelandii were grown together as a dual culture. However, it was necessary that the conditions for the dual culture be such that the Azo. vinelandii cells underwent some lysis. In fact, the initial rate of lysis of the Azo. vinelandii cells was increased in the presence of Act. humiferus, presumably because Act. humiferus was able to remove magnesium from the medium so it was not available to Azo. vinelandii. The magnesium requirement of Act. humiferus for growth initiation could also be replaced by a heat-labile factor found in culture filtrates of Act. humiferus and Azo. vinelandii grown as monocultures and dual cultures. This factor, however, was also present in culture filtrates of Arthrobacter globiformis, Nocardia salmonicolor, and Micrococcus luteus. It was not present in culture filtrates of Escherichia coli, Agromyces ramosus, or Ensifer adhaerens. From these results it appears that several, but not all, bacteria produce a heat-labile factor that is involved in marshalling magnesium for use in growth initiation.

Bacterial control of Agromyces ramosus in soil

1985 ◽  
Vol 31 (12) ◽  
pp. 1157-1163 ◽  
Author(s):  
Jeffrey J. Byrd ◽  
Lawrence R. Zeph ◽  
L. E. Casida Jr.
Keyword(s):  
Soil Bacteria ◽  
Azotobacter Vinelandii ◽  
Bacterial Species ◽  
Initiation Factor ◽  
Natural Soil ◽  
Gram Negative ◽  
Pure Cultures ◽  
Growth Initiation ◽  
Population Sizes ◽  
Relationship Of

Agromyces ramosus occurs in high numbers in many soils. It also is a known predator of various gram-positive and gram-negative soil bacteria, including Azotobacter vinelandii. Based on this, it would seem that, in natural soil, A. ramosus should control the population sizes of these soil bacteria. As a partial test of this assumption, we examined the possibility that soil might contain other bacterial predators that could hold A. ramosus in check. Three gram-negative bacterial predators of A. ramosus were isolated from soil. When one of these predators, strain N-1, was added to natural soil, it exhibited an attack – counter attack phenomenon in its interactions with A. ramosus. The indigenous A. ramosus cells in soil, or added A. ramosus cells, produced mycelium that approached, then lysed, approximately one-third of the N-1 cells. The surviving N-1 cells, however, then proceeded to lyse the A. ramosus mycelium, but not the rod-form cells that had fragmented from the mycelium. Strain N-1 then multiplied. This sequence also occurred if Azotobacter vinelandii was added with A. ramosus to soil, either with or without addition of N-1 cells. N-1 attacked the A. ramosus mycelium that was attacking Azotobacter vinelandii. In soil and with pure cultures in the laboratory, the dormant rod-form cells of A. ramosus that fragmented from the mycelium were not attacked. A growth initiation factor seemed to be involved in the attack – counter attack relationship of N-1 and A. ramosus. Strain N-1 and the other two gram-negative predators mentioned above could attack a variety of bacterial species in soil, in addition to A. ramosus which in itself is a predator. Thus, some sort of hierarchy of bacterial predation seems to exist in soil.

scholarly journals In vitro evaluation of fungal antagonists of Phytophthora nicotianae

2017 ◽  
Vol 38 (SI 2 - 6th Conf EFPP 2002) ◽  
pp. 634-637
Author(s):  
R. Nicoletti ◽  
F. Raimo ◽  
E. Cozzolino
Keyword(s):  
Mycelial Growth ◽  
Central Italy ◽  
Phytophthora Nicotianae ◽  
Aspergillus Sydowii ◽  
Black Shank ◽  
Culture Filtrates ◽  
Dual Cultures ◽  
Penicillium Brevicompactum ◽  
Fusarium Chlamydosporum

As tobacco black shank epidemics caused by Phytophthora nicotianae occurred in central Italy in the late 1990s, fungal antagonists of the pathogen were searched in the rhizosphere of tobacco plants. Isolates of Aspergillus sydowii, Fusarium chlamydosporum, Gliocladium roseum, Penicillium brevicompactum, P. chrysogenum, Scopulariopsis candida and Trichoderma harzianum were recovered. Antagonism of these isolates toward P. nicotianae was evaluated in vitro: even if no hyphal interactions were observed in dual cultures, aberration in mycelial growth and morphology of sporangia occurred in most cases. Unlike those of T. harzianum, concentrated culture filtrates of A. sydowii, F. chlamydosporum, G. roseum, P. brevicompactum, P. chrysogenum, inhibited growth of all P. nicotianae isolates tested, while culture filtrates of S. candida caused aberrant mycelial growth.

Growth of nopaline-utilizing Agrobacterium and Pseudomonas in extracts of crown-gall tumors

1988 ◽  
Vol 34 (6) ◽  
pp. 793-801 ◽  
Author(s):  
B. Saint-Pierre ◽  
P. Dion
Keyword(s):  
Cell Population ◽  
Crown Gall ◽  
Minimal Medium ◽  
Dual Culture ◽  
Carbon And Nitrogen ◽  
Pseudomonas Aureofaciens ◽  
Dual Cultures ◽  
Stem Extract ◽  
Crown Gall Tumors ◽  
The Difference

Two nopaline-utilizing bacteria isolated from the same crown-gall tumor, and identified previously as Agrobacterium tumefaciens and Pseudomonas aureofaciens, were grown in pure or dual culture in various types of media. These included minimal medium with nopaline as the sole carbon and nitrogen source, and intercellular fluid extracted from sunflower or apple. The size of inoculum was similar for the two bacteria, and the ratio of the maximal cell population for P. aureofaciens over that for A. tumefaciens was calculated. This ratio was highest for dual culture in minimal medium, and under these conditions P. aureofaciens utilized most of the nopaline supply. This advantage of Pseudomonas in terms of maximal cell population was reduced for dual cultures in extracts prepared either from uninoculated stems or from tumors that had been induced by the A. tumefaciens isolate. For the two plants studied, the difference between maximal populations of P. aureofaciens and A. tumefaciens was smaller in tumor than in stem extract. The time of disappearance of opines from the tumor extracts was considered in relation with the growth of the two bacteria. Similar analysis was made on cultures involving A. tumefaciens and a mutant pseudomonad deficient in nopaline utilization. These experiments indicated that the differential response of dual cultures of A. tumefaciens and P. aureofaciens to stem or tumor extracts was not due to the presence of opine of the nopaline family in the extracts from crown-gall tumors.

scholarly journals Global transcriptomics analysis of the Desulfovibrio vulgaris change from syntrophic growth with Methanosarcina barkeri to sulfidogenic metabolism

Microbiology ◽  
2010 ◽  
Vol 156 (9) ◽  
pp. 2746-2756 ◽  
Author(s):  
Caroline M. Plugge ◽  
Johannes C. M. Scholten ◽  
David E. Culley ◽  
Lei Nie ◽  
Fred J. Brockman ◽  
...  
Keyword(s):  
Gene Cluster ◽  
Cell Envelope ◽  
Methanosarcina Barkeri ◽  
Desulfovibrio Vulgaris ◽  
Dual Culture ◽  
Dual Cultures ◽  
Genes Encoding ◽  
Energy Conserving ◽  
Membrane Bound ◽  
Functional Analyses

Desulfovibrio vulgaris is a metabolically flexible micro-organism. It can use sulfate as an electron acceptor to catabolize a variety of substrates, or in the absence of sulfate can utilize organic acids and alcohols by forming a syntrophic association with a hydrogen-scavenging partner to relieve inhibition by hydrogen. These alternative metabolic types increase the chance of survival for D. vulgaris in environments where one of the potential external electron acceptors becomes depleted. In this work, whole-genome D. vulgaris microarrays were used to determine relative transcript levels as D. vulgaris shifted its metabolism from syntrophic in a lactate-oxidizing dual-culture with Methanosarcina barkeri to a sulfidogenic metabolism. Syntrophic dual-cultures were grown in two independent chemostats and perturbation was introduced after six volume changes with the addition of sulfate. The results showed that 132 genes were differentially expressed in D. vulgaris 2 h after addition of sulfate. Functional analyses suggested that genes involved in cell envelope and energy metabolism were the most regulated when comparing syntrophic and sulfidogenic metabolism. Upregulation was observed for genes encoding ATPase and the membrane-integrated energy-conserving hydrogenase (Ech) when cells shifted to a sulfidogenic metabolism. A five-gene cluster encoding several lipoproteins and membrane-bound proteins was downregulated when cells were shifted to a sulfidogenic metabolism. Interestingly, this gene cluster has orthologues found only in another syntrophic bacterium, Syntrophobacter fumaroxidans, and four recently sequenced Desulfovibrio strains. This study also identified several novel c-type cytochrome-encoding genes, which may be involved in the sulfidogenic metabolism.

scholarly journals In Vitro Interactions between Eutypella parasitica and Some Frequently Isolated Fungi from the Wood of the Dead Branches of Young Sycamore Maple (Acer pseudoplatanus)

Forests ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 1072
Author(s):  
Ana Brglez ◽  
Barbara Piškur ◽  
Nikica Ogris
Keyword(s):  
Competitive Ability ◽  
Inhibitory Effect ◽  
Antagonistic Activity ◽  
Dual Culture ◽  
Acer Pseudoplatanus ◽  
Dual Cultures ◽  
Weak Competitor ◽  
The Dead ◽  
In Vitro Interactions

The ten most frequently isolated fungi from the wood of the dead branches of Acer pseudoplatanus L. were tested in dual cultures to evaluate their in vitro antagonistic activity against Eutypella parasitica R.W. Davidson and R.C. Lorenz, the causative agent of a destructive disease of maples in Europe and North America. The tested fungi, treated also as challenge isolates, were Diaporthe sp., Eutypa sp., Eu. maura, E. parasitica, Fusarium avenaceum, Neocucurbitaria acerina, Neonectria sp., Peniophora incarnata, Petrakia irregularis, and Phomopsis pustulata. The antagonistic ability of each challenge isolate was evaluated by calculating an index of antagonism (AI) based on the interaction type in the dual cultures. The results of competition between the fungal isolates were quantified after re-isolations from the interaction zone (s). The dual cultures revealed two main types of competitive interactions: Deadlock, consisting of mutual inhibition after mycelial contact or at a distance, and replacement, reflecting in the inhibition of E. parasitica, followed by partial overgrowth by the replacing fungus. Statistical analysis showed significant differences in average AI and s of challenge isolates between different dual culture assays. Based on the results of the antagonism index, Eutypa sp., Eu. maura, Neonectria sp., and P. incarnata had the highest inhibitory effect on E. parasitica growth and were recognized as the most promising candidates for further biocontrol studies of E. parasitica. The mycelium of E. parasitica at the interaction zones remained mostly viable, except in dual cultures with Eutypa sp., F. avenaceum, and Neonectria sp., where re-isolations did not yield any colony of the E. parasitica isolate. Based on the results, we assume that E. parasitica is a weak competitor, which invests less energy in direct mycelial competition. We discuss the potential of the observed antagonists as a possible biocontrol of Eutypella canker of maple. Nevertheless, additional experiments should be performed for a solid conclusion about competitive ability of E. parasitica and usefulness of antagonists as biocontrol.

Colony Interaction and Secondary Metabolite Production of Cheese-Related Fungi in Dual Culture

1998 ◽  
Vol 61 (8) ◽  
pp. 1023-1029 ◽  
Author(s):  
MARIANNE S. NIELSEN ◽  
JENS C. FRISVAD ◽  
PER V. NIELSEN
Keyword(s):  
Agar Medium ◽  
Starter Culture ◽  
Cyclopiazonic Acid ◽  
Geotrichum Candidum ◽  
Starter Cultures ◽  
Dual Culture ◽  
Dual Cultures ◽  
Chaetoglobosin A ◽  
Two Temperatures ◽  
Fungal Contaminants

Interactions between fungi used as starter cultures (Penicillium roqueforti, Penicillium camemberti, Penicillium nalgiovense,and Geotrichum candidum) and fungal contaminants associated with cheese were investigated on agar medium at two temperatures, 18 and 25°C. Mutual inhibition on contact was the most common interaction observed. The only other interaction observed was inhibition of the contaminant, while the starter continued to grow, especially in dual cultures involving G. candidum as the starter culture. Dual cultures involving G. candidum showed inhibition of production of the mycotoxins mycophenolic acid, roquefortin C, chaetoglobosin A, and cyclopiazonic acid produced by the contaminants. An unknown metabolite was detected in considerably larger quantity in dual cultures involving G. candidum compared to detection in single cultures. There was no correlation between detection of this metabolite and the observed interactions. The results show that G. candidum plays a major role in interactions between fungi on cheese.

scholarly journals In vitro antifungal activity of endophytic bacteria isolated from date palm (Phoenix doctylifera L.) against fungal pathogens causing leaf spot of date palm

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
H. H. Al-Nadabi ◽  
N. S. Al-Buraiki ◽  
A. A. Al-Nabhani ◽  
S. N. Maharachchikumbura ◽  
R. Velazhahan ◽  
...  
Keyword(s):  
Leaf Spot ◽  
Endophytic Bacteria ◽  
Mycelial Growth ◽  
Fungal Pathogens ◽  
Date Palm ◽  
Dual Culture ◽  
Bacterial Endophytes ◽  
Bacterial Strains ◽  
Culture Filtrates

Abstract Background Date palm ((Phoenix doctylifera L.) suffers from several fungal diseases. The endophytic microorganisms present in higher plants generally offer protection to their host plants against invading phytopathogenic fungi and bacteria. In the present study, endophytic bacteria associated with date palm leaves were isolated and their in vitro antagonistic potential against fungal pathogens causing leaf spots in date palm was demonstrated. Results Endophytic bacteria were isolated from date palm leaves of 3 different cultivars viz., Nighal, Khalas and Khinaizi and evaluated for their inhibitory activity against leaf spot pathogens of date palm viz., Fusarium solani, Alternaria sp., Nigrospora sp., Thieloviopsis sp., Curvularia subpapendrofii and Tilletiopsis minor using an in vitro dual culture assay. Of the 24 endophytic bacterial strains tested, the endophytes designated B1, B7, B8 and B9 obtained from cv. Nighal showed inhibitory activities (more than 55% mycelial growth inhibition) against F. solani and Alternaria sp. None of the bacterial endophytes inhibited the growth of other fungal pathogens tested. These antagonistic bacterial strains were identified as Pantoea septica on the basis of 16S rRNA gene sequence analysis. The hyphae of F. solani and Alternaria sp. exhibited morphological abnormalities such as shrinkage and disintegration when grown in the presence of antagonistic bacterial endophytes. The cell-free culture filtrates of the bacterial endophytes caused inhibition of mycelial growth and induced leakage of electrolytes from the mycelia of F. solani and Alternaria sp. This is the first study that describes inhibition of the date palm pathogens F. solani and Alternaria sp. by P. septica. Conclusion Endophytic Pantoea septica strains isolated from date palm leaves inhibited the mycelial growth of F. solani and Alternaria sp. and induced morphological changes in their mycelia. The culture filtrates of these bacterial strains also inhibited the mycelial growth and caused leakage of electrolytes from the mycelia of F. solani and Alternaria sp. These promising bacterial strains can be exploited as biocontrol agents to control F. solani and Alternaria sp.-induced leaf spot diseases of date palm.

scholarly journals Cultivatingin situtriggers growth of previously uncultivated microorganisms via a growth initiation factor in nature

2019 ◽  
Author(s):  
Dawoon Jung ◽  
Koshi Machida ◽  
Yoichi Nakao ◽  
Tomonori Kindaichi ◽  
Akiyoshi Ohashi ◽  
...  
Keyword(s):  
Growth Promotion ◽  
Initiation Factor ◽  
Natural Environments ◽  
Controlling System ◽  
Growth Initiation ◽  
Membrane Bound ◽  
Simple Growth ◽  
Specific Growth Rates ◽  
Sponge Extract

AbstractMost microorganisms resist cultivation under standard laboratory conditions. On the other hand, to cultivate microbes in a membrane-bound device incubated in nature (in situcultivation) is an effective approach. In the present study, we appliedin situcultivation to isolate diverse previously uncultivated marine sponge-associated microbes and comparatively analyzed this method’s efficiencies with those of the conventional method. Then, we attempted to clarify the key and unknown mechanism ofin situcultivation by focusing on growth triggering via growth initiation factor. We hypothesized that majority of environmental microorganisms are in nongrowing state and requiring “growth initiation factor” for the recovery and that can be provided from environments. Consequently, significantly more novel and diverse microbial types were isolated viain situcultivation than by standard direct plating (SDP). Next, the effect of the sponge extract on starvation recovery was compared between strains derived fromin situand SDP cultivation. Adding small amounts of the sponge extracts to the medium elevated the colony-formation efficiencies of thein situstrains at the starvation recovery step, while it showed no positive effect on that of SDP strains. Conversely, specific growth rates or carrying capacities of all tested strains were not positively affected. These results indicate that, 1) the sponge extract contains chemical compounds that facilitate starvation recovery, these substances selectively worked on thein situstrains, and 2) growth initiation factor in the sponge extract did not continuously promote growth activity but worked as triggers for regrowth (resuscitation from dormancy).ImportanceMost microbial species resist cultivation under laboratory condition. This is critical impediment for both academic and applied microbiology, and thus clarification of the mechanism of microbial uncultivability is highly demanded. Several evidences have been reported that to cultivate microbes in a membrane-bound device incubated in nature (in situcultivation) is an effective approach. However, the mechanism behind this approach has not been clarified. The present study shows the evidence that 1) initiating growth is a key for cultivating previously uncultivated microbes rather than simple growth promotion, and 2) growth initiation factor (signaling-like compounds) in natural environments stimulate microbial resuscitation from a nongrowing state. Since no study has focused on growth initiation for cultivation of previously uncultivated microorganisms, the discovery shown in the present study provides a new insight into microorganisms previously considered uncultivable and a microbial growth controlling system in nature.

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