Role of Marine Fungi in the Biochemistry of the Oceans. V. Patterns of Constitutive Nutritional Growth Responses

Mutants of Apergillus nidulanswith lesions in a gene, areA (formerly called amdT), have been isolated by a variety of different selection methods. The areA mutants show a range of pleiotropic growth responses to a number of compounds as sole nitrogen sources, but are normal in utilization of carbon sources. The levels of two amidase enzymes as well as urease have been investigated in the mutants and have been shown to be affected by this gene. Most of the areA mutants have much lower amidase-specific activities when grown in ammonium-containing medium, compared with mycelium incubated in medium la9king a nitrogen source. Some of the areA. mutants do not show derepression of urease upon relief of ammonium repression. The dominance relationships of areA alleles have been investigated in� heterozygous diploids, and these studies lend support to the proposal that areA codes for a positively acting regulatory product. One of the new areA alleles is partially dominant to areA + and areA102. This may be a result of negative complementation or indicate that areA has an additional negative reiuIatory function. Investigation.of various amdR; areA double mutants has led to the conclusion that amdR and areA participate in independent regulatory circuits in the control of acetamide utilizatiol1. Studies on an amdRc; areA.double mutant indicate that areA is involved in derepression of acetamidase upon relief of ammo.nium repression.

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Akt2 Regulates Cardiac Metabolism and Cardiomyocyte Survival

Journal of Biological Chemistry ◽

10.1074/jbc.m513087200 ◽

2006 ◽

Vol 281 (43) ◽

pp. 32841-32851 ◽

Cited By ~ 110

Author(s):

Brian DeBosch ◽

Nandakumar Sambandam ◽

Carla Weinheimer ◽

Michael Courtois ◽

Anthony J. Muslin

Keyword(s):

Pressure Overload ◽

Cardiac Metabolism ◽

Cellular Protein ◽

Growth Responses ◽

Infarct Zone ◽

Targeted Disruption ◽

Cellular Processes ◽

Ligand Stimulation ◽

And Function

The Akt family of serine-threonine kinases participates in diverse cellular processes, including the promotion of cell survival, glucose metabolism, and cellular protein synthesis. All three known Akt family members, Akt1, Akt2 and Akt3, are expressed in the myocardium, although Akt1 and Akt2 are most abundant. Previous studies demonstrated that Akt1 and Akt3 overexpression results in enhanced myocardial size and function. Yet, little is known about the role of Akt2 in modulating cardiac metabolism, survival, and growth. Here, we utilize murine models with targeted disruption of the akt2 or the akt1 genes to demonstrate that Akt2, but not Akt1, is required for insulin-stimulated 2-[3H]deoxyglucose uptake and metabolism. In contrast, akt2-/- mice displayed normal cardiac growth responses to provocative stimulation, including ligand stimulation of cultured cardiomyocytes, pressure overload by transverse aortic constriction, and myocardial infarction. However, akt2-/- mice were found to be sensitized to cardiomyocyte apoptosis in response to ischemic injury, and apoptosis was significantly increased in the peri-infarct zone of akt2-/- hearts 7 days after occlusion of the left coronary artery. These results implicate Akt2 in the regulation of cardiomyocyte metabolism and survival.

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The role of nematodes, fungi, bacteria, and abiotic factors in the etiology of apple replant problems in the Granite Belt of Queensland

Australian Journal of Experimental Agriculture ◽

10.1071/ea9941177 ◽

1994 ◽

Vol 34 (8) ◽

pp. 1177 ◽

Cited By ~ 32

Author(s):

SR Dullahide ◽

GR Stirling ◽

A Nikulin ◽

AM Stirling

Keyword(s):

Abiotic Factors ◽

Dry Weight ◽

Pratylenchus Penetrans ◽

Growth Responses ◽

Granite Belt ◽

Pathogenicity Tests ◽

Phosphorus And Potassium ◽

Orchard Soils ◽

Fusarium Tricinctum

Investigations of apple replant failure in the Granite Belt suggested that the problem had a complex etiology. Soil fertility was an important factor because apple seedlings grew best in replant soils with high levels of nitrogen, phosphorus, and potassium. Consistent improvements in the growth of apple seedlings were obtained when typical orchard soils were treated with fenamiphos, confirming that lesion nematode was also an important component of the disease complex. Pratylenchus penetrans had been recognised as a pathogen of apples, and pathogenicity tests showed that P. jordanensis, another species widely distributed in the Granite Belt, had similar effects. Growth responses of apple seedlings were greater when soil was pasteurised than when it was treated with fenamiphos, suggesting that root pathogens other than nematodes were involved in apple replant failure. However, the primary cause probably differed between orchards because soils did not respond in the same manner to pasteurisation and nematicide treatments. Pathogenicity tests with 14 bacteria associated with apple roots showed no effect on the growth of apple seedlings. However, Fusarium tricinctum, Cylindrocarpon destructans, and Pythium sp. were implicated in the problem because they were consistently recovered from discoloured roots. In a factorial experiment involving nematodes and fungi in pots, P. jordanensis, P. penetrans, E. tricinctum, and C. destructans reduced the dry weight of apple roots but there was no interaction between nematodes and fungi.

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Diversity and species turnover on an altitudinal gradient in Western Cape, South Africa: baseline data for monitoring range shifts in response to climate change

Bothalia ◽

10.4102/abc.v38i2.287 ◽

2008 ◽

Vol 38 (2) ◽

Cited By ~ 9

Author(s):

L. Agenbag ◽

K. J. Elser ◽

G. F. Midgley ◽

C. Boucher

Keyword(s):

Climate Change ◽

Growth Form ◽

Species Turnover ◽

Moisture Gradient ◽

Range Shifts ◽

Western Cape ◽

Growth Responses ◽

Succulent Karoo ◽

Species Ranges

A temperature and moisture gradient on the equator-facing slope of Jonaskop on the Riviersonderend Mountain. Westem Cape has been selected as an important gradient for monitoring the effects of climate change on fynbos and the Fynbos- Succulent Karoo ecotone. This study provides a description of plant diversity patterns, growth form composition and species turnover across the gradient and the results of four years of climate monitoring at selected points along the altitudinal gradient.The aim o f this study is to provide data for a focused monitoring strategy for the early detection of climate change-related shifts in species’ ranges, as well as gaining a better understanding of the role of climate variability in shaping species growth responses, their distributions, and other ecosystem processes.

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ROLE OF MARINE FUNGI IN THE BIOCHEMISTRY OF THE OCEANS: III. GROWTH FACTOR REQUIREMENTS OF THE ASCOMYCETE HALOSPHAERIA MEDIOSETIGERA

Canadian Journal of Microbiology ◽

10.1139/m63-075 ◽

1963 ◽

Vol 9 (4) ◽

pp. 585-591 ◽

Cited By ~ 5

Author(s):

Peter L. Sguros ◽

Jacqueline Simms

Keyword(s):

Growth Factor ◽

Yeast Extract ◽

Gulf Stream ◽

Mycelial Growth ◽

Marine Fungi ◽

Wood Flour ◽

Aqueous Extracts ◽

Absolute Requirement ◽

Mycelial Development

Certain growth factor requirements of the cellulolytic marine ascomycete, Halosphaeria mediosetigera, in glucose – inorganic salts media, have been determined. Yeast extract, containing required nutrilites, proved superior to other empirical mixtures in the support of mycelial growth. Aqueous extracts of several varieties of wood flour could not replace yeast extract. Gulf Stream seawater was unable to provide the necessary growth factors. An absolute requirement for 5 to 10 μg thiamine per liter has been demonstrated for maximal mycelial development. Further data showed a requirement for biotin which was both partial and transient.

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Rewiring of auxin signaling under persistent shade

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1721110115 ◽

2018 ◽

Vol 115 (21) ◽

pp. 5612-5617 ◽

Cited By ~ 21

Author(s):

Ornella Pucciariello ◽

Martina Legris ◽

Cecilia Costigliolo Rojas ◽

María José Iglesias ◽

Carlos Esteban Hernando ◽

...

Keyword(s):

Physiological Role ◽

System Level ◽

Early Event ◽

Auxin Signaling ◽

Detailed Knowledge ◽

Shade Avoidance ◽

Growth Responses ◽

Molecular Events ◽

Elevated Expression

Light cues from neighboring vegetation rapidly initiate plant shade-avoidance responses. Despite our detailed knowledge of the early steps of this response, the molecular events under prolonged shade are largely unclear. Here we show that persistent neighbor cues reinforce growth responses in addition to promoting auxin-responsive gene expression in Arabidopsis and soybean. However, while the elevation of auxin levels is well established as an early event, in Arabidopsis, the response to prolonged shade occurs when auxin levels have declined to the prestimulation values. Remarkably, the sustained low activity of phytochrome B under prolonged shade led to (i) decreased levels of PHYTOCHROME INTERACTING FACTOR 4 (PIF4) in the cotyledons (the organs that supply auxin) along with increased levels in the vascular tissues of the stem, (ii) elevated expression of the PIF4 targets INDOLE-3-ACETIC ACID 19 (IAA19) and IAA29, which in turn reduced the expression of the growth-repressive IAA17 regulator, (iii) reduced abundance of AUXIN RESPONSE FACTOR 6, (iv) reduced expression of MIR393 and increased abundance of its targets, the auxin receptors, and (v) elevated auxin signaling as indicated by molecular markers. Mathematical and genetic analyses support the physiological role of this system-level rearrangement. We propose that prolonged shade rewires the connectivity between light and auxin signaling to sustain shade avoidance without enhanced auxin levels.

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