Floater interference reflects territory quality in the Spanish Imperial EagleAquila adalberti: a test of a density-dependent mechanism

Microtubules (MTs) often form a polarized array with minus-ends anchored at the centrosome and plus-ends extended towards the cell margins. Plus-ends display behavior known as dynamic instability, – transitions between rapid shortening and slow growth. It is known that dynamic instability is regulated locally to ensure entry of MTs into nascent areas of cytoplasm, but details of this regulation remain largely unknown. Here, we test alternative hypothesis for the local regulation of MT behavior. We used microsurgery to isolate a portion of peripheral cytoplasm from MTs growing from the centrosome, crating cytoplasmic areas locally depleted of MTs. We found that in sparsely populated areas MT plus-ends persistently grew or paused but never shortened. In contrast, plus-ends that entered regions of cytoplasm densely populated with MTs frequently transitioned to shortening. Persistent growth of MTs in sparsely populated areas could not be explained by a local increase in concentration of free tubulin subunits or elevation of Rac1 activity proposed to enhance MT growth at the cell leading edge during locomotion. These observations suggest the existence of a MT-density dependent mechanism regulating MT dynamics that determines dynamic instability of MTs in densely populated areas of the cytoplasm and persistent growth in sparsely populated areas. [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text]

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The adiponectin paralog CTRP9 but not CTRP7 mediates anti-oxidative effects in adult rat cardiomyocytes through an AMPK, adiponectin receptor and calreticulin dependent mechanism

Diabetologie und Stoffwechsel ◽

10.1055/s-0035-1549595 ◽

2015 ◽

Vol 10 (S 01) ◽

Author(s):

L Li ◽

D Stumpp ◽

B Siegler ◽

M Micoogullari ◽

B Niemann ◽

...

Keyword(s):

Adiponectin Receptor ◽

Rat Cardiomyocytes ◽

Adult Rat ◽

Oxidative Effects ◽

Dependent Mechanism

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Platelet Mobilization Induced by PAF and Its Role in the Thrombocytosis Triggered by Adrenaline in Rats

Thrombosis and Haemostasis ◽

10.1055/s-0038-1647127 ◽

1989 ◽

Vol 62 (04) ◽

pp. 1107-1111 ◽

Cited By ~ 5

Author(s):

Hugo C Castro-Faria-Neto ◽

Patricia T Bozza ◽

Marco A Martins ◽

Paulo M F L Dias ◽

Patricia M R Silva ◽

...

Keyword(s):

Receptor Antagonists ◽

Blood Samples ◽

Platelet Counts ◽

Platelet Number ◽

Edta Solution ◽

Web 2086 ◽

Dependent Mechanism

SummaryThe injection of PAP (6 μg/kg, i. v.) induced, in rats, haemoconcentration accompanied by an increase in the platelet number, as attested by the counts of platelets in blood samples diluted in formalin-free EDTA solution. This increase was significant at 15 min, peaked from 1 to 4 h and returned to basal levels 24 h after the lipid administration. The release of platelets induced by PAP was inhibited dose-dependently by specific PAP receptor antagonists such as WEB 2086 (0.5-2 mg/kg), BN 52021 and 48740 RP (5-25 mg/kg). Furthermore, platelet mobilization was clearly impaired in splenectomized animals stimulated by PAP, whereas thrombocytopenia and haemoconcentration by the same stimulus were intact. It was also noted that a second injection of PAP, 24 h after the initial stimulation with the lipid, failed to induce an increase in platelet counts, indicating autodesensitization. Desensitization to PAP or pretreatment with PAP antagonists clearly prevented the increase in the platelet counts after stimulation by adrenaline (15 μg/kg). These findings suggest that, in rats, PAP can induce release of platelets by a spleen-dependent mechanism and that this lipid may be relevant to the thrombocytosis triggered by adrenaline.

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Urbanization impacts on production and recruitment of Fundulus heteroclitus in salt marsh creeks

Marine Ecology Progress Series ◽

10.3354/meps13378 ◽

2020 ◽

Vol 645 ◽

pp. 187-204

Author(s):

PJ Rudershausen ◽

JA Buckel

Keyword(s):

Salt Marsh ◽

Salt Marshes ◽

Fundulus Heteroclitus ◽

Multiple Factor Analysis ◽

Southeastern Usa ◽

Density Dependent ◽

Dependent Relationship ◽

Juvenile Abundance ◽

The Relationship ◽

Throw Trap

It is unclear how urbanization affects secondary biological production in estuaries in the southeastern USA. We estimated production of larval/juvenile Fundulus heteroclitus in salt marsh areas of North Carolina tidal creeks and tested for factors influencing production. F. heteroclitus were collected with a throw trap in salt marshes of 5 creeks subjected to a range of urbanization intensities. Multiple factor analysis (MFA) was used to reduce dimensionality of habitat and urbanization effects in the creeks and their watersheds. Production was then related to the first 2 dimensions of the MFA, month, and year. Lastly, we determined the relationship between creek-wide larval/juvenile production and abundance from spring and abundance of adults from autumn of the same year. Production in marsh (g m-2 d-1) varied between years and was negatively related to the MFA dimension that indexed salt marsh; higher rates of production were related to creeks with higher percentages of marsh. An asymptotic relationship was found between abundance of adults and creek-wide production of larvae/juveniles and an even stronger density-dependent relationship was found between abundance of adults and creek-wide larval/juvenile abundance. Results demonstrate (1) the ability of F. heteroclitus to maintain production within salt marsh in creeks with a lesser percentage of marsh as long as this habitat is not removed altogether and (2) a density-dependent link between age-0 production/abundance and subsequent adult recruitment. Given the relationship between production and marsh area, natural resource agencies should consider impacts of development on production when permitting construction in the southeastern USA.

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