In vitro measurements of the competitive interactions between two saprobic basidiomycetes on Typha latifolia

2005 ◽  
Vol 83 (11) ◽  
pp. 1523-1527 ◽  
Author(s):  
Michael J. Schulz ◽  
James F. Cahill, ◽  
Randolph S. Currah

Psathyrella typhae (Kalchbr.) Pearson & Dennis forms small basidiomata (mushrooms) and Sclerotium hydrophilum Saccardo in Rothert numerous minute sclerotia at the base of senescent shoots of Typha latifolia L. To assess how the two might compete in nature, isolates of these fungi were paired on autoclaved leaf segments of T. latifolia and incubated at 15 and 25 °C. The relative abundance of each species in the segments was determined by macerating the leaf tissues and then transferring fragments of macerate to microplates containing two types of media: one conclusively demonstrated the presence of P. typhae while the other demonstrated the presence of S. hydrophilum. Relative numbers of microplate wells showing positive reactions for each species on each medium indicated the proportion of the segment occupied following single and paired inoculations. These data demonstrated that competition was asymmetric, with P. typhae the stronger competitor at both temperatures, and uninhibited by the presence of S. hydrophilum. In contrast, S. hydrophilum was competitively excluded by P. typhae.

1973 ◽  
Vol 28 (1-2) ◽  
pp. 45-58 ◽  
Author(s):  
Hansjörg A. W. Schneider

The activities of enzymes related with chlorophyll and porphyrin synthesis have been examined during development and greening of young corn leaves. The enzymes succinyl-CoA-synthetase (SCoAS), δ-amino-levulinate synthetase (ALAS), δ-amino-levulinate dehydratase (ALAD) and the enzymes involved in porphobilinogenase (PBGA) were under investigaton. When leaves are illuminated and chlorophyll synthesis begins the activity of ALAD is not influenced. The activity of PBGA and SCoAS are slightly higher than in darkness, but the changes are below the range affecting chlorophyll biosynthesis. ALA, however, is only synthetized in the light. Synthesis ceases immediately when illuminiation ist stopped, indicating'that in darkness ALAS is not active. On the other hand ALAS is active in dark grown roots, tubers and other non-leaf tissues. Feeding the plant with succinate, glycine or α-keto-glutarate has no effect on chlorophyll synthesis, but the amount of ALA is reduced, whereas sucrose promotes its accumulation. The results are discussed with completely antitethaal results obtained with tissue cultures of tobacco and are integrated into a scheme which excludes the contrariety of hypotheses deduced from experi- ments with inhibitors of protein and nucleic acid synthesis. It is suggested that the varying results are caused by the action of light on different stages in differentiation of plastids and cells. In contrast to the enzymes SCoAS, ALAD and PBGA whose activities were determined in vitro, ALAS was assayed in vivo by means of the accumulation of (5-amino-levulinate (ALA) after blocking the enzyme ALAD by levulinate (LA). Optimum accumulation is observed when the concentration is about 2 · 10-2 м. LA is not converted to ALA in appreciable amounts. This could be proved by feeding the plants with 14C-LA which was prepared from uniformly labeled 14C-fructose.


1998 ◽  
Vol 64 (12) ◽  
pp. 4830-4833 ◽  
Author(s):  
Peter H. Janssen

ABSTRACT Strain VeGlc2, an anaerobic ultramicrobacterium belonging to theVerrucomicrobiales lineage of bacterial descent, fermented glucose to acetate, propionate, succinate, and CO2. The distribution of radiolabel in the fermentation end products produced from position-labelled glucose and in vitro measurements of enzyme activities in crude cell extracts prepared from glucose-grown cells showed that glucose was metabolized via the Embden-Meyerhof-Parnas pathway. The 6-phosphofructokinase (EC 2.7.1.90 ) activity required pyrophosphate as the phosphoryl donor, and ATP could not replace pyrophosphate. The other enzyme activities were those of a classical Embden-Meyerhof-Parnas pathway. 14CO2 was incorporated into propionate and succinate, suggesting that a carboxylation reaction rather than a transcarboxylation reaction was involved in the reductive pathway leading to succinate and propionate. Difference spectra showed that a type b cytochrome was present, which could be involved in electron transport in the reductive pathway.


2019 ◽  
Author(s):  
Gina Paola Rodriguez-Castaño ◽  
Federico E. Rey ◽  
Alejandro Caro-Quintero ◽  
Alejandro Acosta-González

AbstractFlavonoids are a common component of the human diet with widely reported health-promoting properties. The gut microbiota transforms these compounds affecting the overall metabolic outcome of their consumption. Flavonoid-degrading bacteria are often studied in isolation under culture conditions that do not resemble the conditions in the colon and that eliminate the multiple interactions that take place in complex communities. In this study, a comparative metataxonomic analysis of fecal communities supplemented with the flavonoid quercetin led us to identify a potential competitive exclusion interaction between two sequence variants related to the flavonoid-degrading species, Flavonifractor plautii, that belong to the same genus but different species. During incubation of fecal slurries with quercetin, the relative abundance of these two variants was inversely correlated; one variant, ASV_65f4, increased in relative abundance in half of the libraries and the other variant, ASV_a45d, in the other half. This pattern was also observed with 6 additional fecal samples that were transplanted into germ-free mice fed two different diets. Mouse’s diet did not change the pattern of dominance of either variant, and initial relative abundances did not predict which one ended up dominating. Potential distinct metabolic capabilities of these two Flavonifractor-related species were evidenced, as only one variant, ASV_65f4, became consistently enriched in complex communities supplemented with acetate but no quercetin. Genomic comparison analysis of the close relatives of each variant revealed that ASV_65f4 may be an efficient ethanolamine-utilizing bacterium which may increase its fitness in media with no quercetin compared to ASV_a45d. Other discordant features between ASV_65f4- and ASV_a45d-related groups may be the presence of flagellar and galactose-utilization genes, respectively. Overall, we showed that the Flavonifractor genus harbors variants that present a pattern of negative co-occurrence and that may have different metabolic and structural traits, whether these differences affect the dynamic of quercetin degradation warrants further investigation.


Zygote ◽  
2021 ◽  
pp. 1-9
Author(s):  
Satish Kumar ◽  
Manmohan Singh Chauhan

Summary The present study was undertaken to analyze the relative abundance (RA) of pluripotency-associated genes (NANOG, OCT4, SOX2, c-MYC, and FOXD3) in different grades of immature oocytes and various stages of in vitro-produced buffalo embryos using RT-qPCR. Results showed that the RA of NANOG, OCT4, and FOXD3 transcripts was significantly higher (P < 0.05) in A grade oocytes compared with the other grades of oocytes. The RA of the c-MYC transcript was significantly higher (P < 0.05) in A grade compared with the C and D grades of oocytes, but the values did not differ significantly from the B grade of oocytes. The RA of the SOX2 transcript was almost similar in all grades of the oocytes. The expression levels of NANOG (P > 0.05), OCT4 (P > 0.05), c-MYC (P > 0.05) and SOX2 (P < 0.05) were higher in the blastocysts compared with the other stages of the embryos. Markedly, FOXD3 expression was significantly higher (P < 0.05) in 8–16-cell embryos compared with the 2-cell and 4-cell embryos and blastocyst, but did not differ significantly from the morula stage of the embryos. In the study, the majority of pluripotency-associated genes showed higher expression in A grade immature oocytes. Therefore, it is concluded that the A grade oocytes appeared to be more developmental competent and are suitable candidates for nuclear cloning research in buffalo. In buffalo, NANOG, OCT4, SOX2, and c-MYC are highly expressed in blastocysts compared with the other stages of embryos.


PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0227724
Author(s):  
Gina Paola Rodriguez-Castaño ◽  
Federico E. Rey ◽  
Alejandro Caro-Quintero ◽  
Alejandro Acosta-González

Flavonoids are a common component of the human diet with widely reported health-promoting properties. The gut microbiota transforms these compounds affecting the overall metabolic outcome of flavonoid consumption. Flavonoid-degrading bacteria are often studied in pure and mixed cultures but the multiple interactions between quercetin-degraders and the rest of the community have been overlooked. In this study, a comparative metataxonomic analysis of fecal communities supplemented with the flavonoid quercetin led us to identify a potential competitive exclusion interaction between two sequence variants related to the flavonoid-degrading species, Flavonifractor plautii, that belong to the same genus but different species. During incubation of fecal slurries with quercetin, the relative abundance of these two variants was inversely correlated; one variant, ASV_65f4, increased in relative abundance in half of the libraries and the other variant, ASV_a45d, in the other half. This pattern was also observed with 6 additional fecal samples that were transplanted into germ-free mice fed two different diets. Mouse’s diet did not change the pattern of dominance of either variant, and initial relative abundances did not predict which one ended up dominating. Potential distinct metabolic capabilities of these two Flavonifractor-related species were evidenced, as only one variant, ASV_65f4, became consistently enriched in complex communities supplemented with acetate but without quercetin. Genomic comparison analysis of the close relatives of each variant revealed that ASV_65f4 may be an efficient utilizer of ethanolamine which is formed from the phospholipid phosphatidylethanolamine that is abundant in the gut and feces. Other discordant features between ASV_65f4- and ASV_a45d-related groups may be the presence of flagellar and galactose-utilization genes, respectively. Overall, we showed that the Flavonifractor genus harbors variants that present a pattern of negative co-occurrence and that may have different metabolic and morphological traits, whether these differences affect the dynamic of quercetin degradation warrants further investigation.


1973 ◽  
Vol 29 (02) ◽  
pp. 490-498 ◽  
Author(s):  
Hiroh Yamazaki ◽  
Itsuro Kobayashi ◽  
Tadahiro Sano ◽  
Takio Shimamoto

SummaryThe authors previously reported a transient decrease in adhesive platelet count and an enhancement of blood coagulability after administration of a small amount of adrenaline (0.1-1 µg per Kg, i. v.) in man and rabbit. In such circumstances, the sensitivity of platelets to aggregation induced by ADP was studied by an optical density method. Five minutes after i. v. injection of 1 µg per Kg of adrenaline in 10 rabbits, intensity of platelet aggregation increased to 115.1 ± 4.9% (mean ± S. E.) by 10∼5 molar, 121.8 ± 7.8% by 3 × 10-6 molar and 129.4 ± 12.8% of the value before the injection by 10”6 molar ADP. The difference was statistically significant (P<0.01-0.05). The above change was not observed in each group of rabbits injected with saline, 1 µg per Kg of 1-noradrenaline or 0.1 and 10 µg per Kg of adrenaline. Also, it was prevented by oral administration of 10 mg per Kg of phenoxybenzamine or propranolol or aspirin or pyridinolcarbamate 3 hours before the challenge. On the other hand, the enhancement of ADP-induced platelet aggregation was not observed in vitro, when 10-5 or 3 × 10-6 molar and 129.4 ± 12.8% of the value before 10∼6 molar ADP was added to citrated platelet rich plasma (CPRP) of rabbit after incubation at 37°C for 30 second with 0.01, 0.1, 1, 10 or 100 µg per ml of adrenaline or noradrenaline. These results suggest an important interaction between endothelial surface and platelets in connection with the enhancement of ADP-induced platelet aggregation by adrenaline in vivo.


1965 ◽  
Vol 50 (2) ◽  
pp. 301-309 ◽  
Author(s):  
Jürg Müller

ABSTRACT An extract of human urine, which was previously shown to stimulate aldosterone production by rat adrenal sections, was further purified. Evidence was obtained that its aldosterone-stimulating effect was due to the presence of ammonium ions. Addition of ammonium chloride and of urine extract to the incubation medium caused identical increases in aldosterone production in vitro. In addition to ammonium ions, rubidium and caesium ions also stimulated aldosterone production up to 250% that of control values without a significant effect on corticosterone production. Similar dose-response curves were obtained when increasing concentrations of potassium, ammonium, rubidium and caesium ions were tested. Aldosterone production was maximal at concentrations of 7 mval/1 and was significantly lower at higher concentrations. When ammonium chloride and ACTH were simultaneously added to the incubation medium, the production of aldosterone and of corticosterone was lower than with ACTH alone. On the other hand, the stimulating activity on aldosterone and corticosterone production by »TPN« (NADP) and glucose-6-phosphate was enhanced by the simultaneous addition of ammonium chloride.


1974 ◽  
Vol 77 (1) ◽  
pp. 64-70 ◽  
Author(s):  
Gustav Wägar

ABSTRACT Whether the short-term regulation of thyroidal protein synthesis by TSH occurs at the transcriptional or the translational level was tested by measuring the effect of actinomycin D (act D) on the TSH-induced stimulation of L-14C-leucine incorporation into the thyroidal proteins of rats. TSH was injected 6 h before the rats were killed. The thyroid glands were then removed and incubated in vitro in the presence of L-14C-leucine for 2 h. The pronounced stimulation of leucine incorporation in the TSH-treated animals was depressed as compared with controls but still significant even when the animals had been pre-treated with 100 μg act D 24 and 7 h before sacrifice. On the other hand, act D strongly decreased incorporation of 3H-uridine into RNA. Short-term regulation of thyroidal protein synthesis by TSH appears to be partly but not wholly dependent on neosynthesis of RNA. Hence regulation may partly occur at the translation level of protein synthesis.


1993 ◽  
Vol 62 (3) ◽  
pp. 619-624 ◽  
Author(s):  
Yu Zhu ◽  
Tetsuyuki Takemoto ◽  
Susumu Yazawa

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 461d-461
Author(s):  
Richard L. Bell ◽  
Ralph Scorza ◽  
Chinnathambi Srinivasan

An efficient regeneration/transformation system was developed for `Beurre Bosc' pear. Young leaves were harvested from in vitro shoots proliferated on a medium containing MS basal salts and 5 BAP, 0.5 μM IBA, and 0.6M3. Shoot regeneration was optimized using a modification of the medium of Chevreau and Leblay (1993). Explants were cultured on shoot induction medium contained 10 μM TDZ and 1 μM IBA for 4 weeks in the dark, and then transfered to a similar, but auxinless, regeneration medium until shoots developed, usually after an additional 4 to 8 weeks. Leaf tissues were transformed by co-cultivation for 3 days with Agrobacterium tumefaciens EHA101 carrying a pGA482 plasmid containing NPTII, GUS, and rolC genes, followed by cultivation on SIM containing 300 mg/L timentin. Putative transgenic plants were selected on shoot induction medium containing 80mg/L kanamycin, and multiplied on shoot proliferation medium. Four clones were confirmed as transgenic using the GUS histochemical assay and Southern blots for the NPTII and rolC genes. Plants of each clone have been rooted and successfully transfered to the greenhouse for further analysis of gene expression.


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