Relationship of the cGMP-binding activity to the cGMP-specific phosphodiesterase in Dictyostelium discoideum

1986 ◽  
Vol 64 (6) ◽  
pp. 528-534 ◽  
Author(s):  
A. M. Parissenti ◽  
M. B. Coukell

Optimal conditions for assaying and stabilizing the soluble cGMP-binding activity in Dictyostelium discoideum were established. Using these procedures, we investigated the relationship between the cGMP-binding activity and the cGMP-specific phosphodiesterase in this organism. In wild-type strains, the binding and phosphodiesterase activities were found to be regulated differently during development. Also, stmF mutants, which possess very low levels of cGMP-specific phosphodiesterase activity, exhibited normal levels of cGMP-binding activity. Fractionation studies revealed that the binding and phosphodiesterase activities could be resolved by DEAE-cellulose chromatography. Finally, the effect of pH on cGMP binding was different from that reported for cGMP-mediated activation of the phosphodiesterase. Taken together, these results indicate that the cGMP-binding protein and the cGMP-specific phosphodiesterase are probably unrelated. In addition, the cGMP-binding activity is not associated with cGMP-stimulated kinase activity and it does not elute from DEAE-cellulose like the highly conserved cGMP-dependent protein kinases found in other systems.

PEDIATRICS ◽  
1960 ◽  
Vol 26 (5) ◽  
pp. 817-821
Author(s):  
Thomas F. Dolan ◽  
Norman B. McCullough ◽  
Lewis E. Gibson

An unusual patient, characterized by recurrent infections, hepatosplenomegaly, low levels of gamma-globulin in the serum (400 mg/100 ml) and lymphocytosis, is described. The patient had pneumonia due to Nocardia asteroides followed by chronic Salmonella newport infection of 16 months' duration, kept in check by continuous antibiotic therapy. No antibodies were produced against specific antigenic challenges. The relationship of this case to those of congenital and acquired agammaglobulinemia is discussed.


2015 ◽  
Vol 67 (6) ◽  
pp. 1510-1518
Author(s):  
S.A. Headley ◽  
T.R. Santos ◽  
L. Bodnar ◽  
J.P.E. Saut ◽  
A.P. Silva ◽  
...  

This study investigated the occurrence of canine distemper virus (CDV) by evaluating the presence of viral RNA within urine samples of dogs from Uberlândia, MG, with clinical manifestations suggestive of infection by CDV by targeting the CDV N gene. Of the clinical samples collected ( n =33), CDV viruria was detected in 45.5%. Five dogs died spontaneously; all had characteristic CDV-associated histopathological alterations and demonstrated CDV viruria. Statistical analyses revealed that the age, gender, breed, or the organ system of the dog affected had no influence on the occurrence of canine distemper. Myoclonus and motor incoordination were the most significant neurological manifestations observed. A direct association was observed between keratoconjunctivitis and dogs with CDV viruria. These findings suggest that CDV viruria in symptomatic dogs might not be age related, and that symptomatic dogs can demonstrate clinical manifestations attributed to CDV without viruria identified by RT-PCR. Additionally, the results of the sequence identities analysed have suggested that all Brazilian wild-type strains of CDV currently identified are closely related and probably originated from the same lineage of CDV. Nevertheless, phylogenetic analyses suggest that there are different clusters of wild-type strains of CDV circulating within urban canine populations in Brazil.


1977 ◽  
Vol 67 (3) ◽  
pp. 391-404 ◽  
Author(s):  
E. A. Bernays ◽  
R. F. Chapman ◽  
E. M. Leather ◽  
A. R. McCaffery ◽  
W. W. D. Modder

AbstractField and laboratory studies at Ibadan, Nigeria, showed that the young nymphs of Zonocerus variegatus (L.) normally reject cassava after biting it and die if they are confined on growing leaves. Later instars will eat cassava, especially when deprived of food for some time, but the adults progressively lose weight when restricted to feeding on growing cassava. On cut cassava, on the other hand, extensive feeding occurs and normal growth is maintained. The change from unpalatability to acceptability occurs within about an hour of cutting and is apparently associated with wilting. Cassava produces latex, but this was not distasteful to Zonocerus. The readiness to feed on growing cassava was associated with low levels of hydrogen cyanide production by the leaves; wilted leaves still produced hydrogen cyanide, but at a lower rate than turgid, growing leaves. In the area around Ibadan, Zonocerus regularly defoliates cassava in the latter part of the dry season, probably because a shortage of attractive foods forces the insect to eat cassava.


2004 ◽  
Vol 3 (5) ◽  
pp. 1176-1184 ◽  
Author(s):  
Tong Gao ◽  
David Knecht ◽  
Lei Tang ◽  
R. Diane Hatton ◽  
Richard H. Gomer

ABSTRACT Little is known about how individual cells can organize themselves to form structures of a given size. During development, Dictyostelium discoideum aggregates in dendritic streams and forms groups of ∼20,000 cells. D. discoideum regulates group size by secreting and simultaneously sensing a multiprotein complex called counting factor (CF). If there are too many cells in a stream, the associated high concentration of CF will decrease cell-cell adhesion and increase cell motility, causing aggregation streams to break up. The pulses of cyclic AMP (cAMP) that mediate aggregation cause a transient translocation of Akt/protein kinase B (Akt/PKB) to the leading edge of the plasma membrane and a concomitant activation of the kinase activity, which in turn stimulates motility. We found that countin− cells (which lack bioactive CF) and wild-type cells starved in the presence of anticountin antibodies (which block CF activity) showed a decreased level of cAMP-stimulated Akt/PKB membrane translocation and kinase activity compared to parental wild-type cells. Recombinant countin has the bioactivity of CF, and a 1-min treatment of cells with recombinant countin potentiated Akt/PKB translocation to membranes and Akt/PKB activity. Western blotting of total cell lysates indicated that countin does not affect the total level of Akt/PKB. Fluorescence microscopy of cells expressing an Akt/PKB pleckstrin homology domain-green fluorescent protein (PH-GFP) fusion protein indicated that recombinant countin and anti-countin antibodies do not obviously alter the distribution of Akt/PKB PH-GFP when it translocates to the membrane. Our data indicate that CF increases motility by potentiating the cAMP-stimulated activation and translocation of Akt/PKB.


2005 ◽  
Vol 12 (4) ◽  
pp. 381-390 ◽  
Author(s):  
Mary C Corley ◽  
Ptlene Minick ◽  
R K Elswick ◽  
Mary Jacobs

This study examined the relationship between moral distress intensity, moral distress frequency and the ethical work environment, and explored the relationship of demographic characteristics to moral distress intensity and frequency. A group of 106 nurses from two large medical centers reported moderate levels of moral distress intensity, low levels of moral distress frequency, and a moderately positive ethical work environment. Moral distress intensity and ethical work environment were correlated with moral distress frequency. Age was negatively correlated with moral distress intensity, whereas being African American was related to higher levels of moral distress intensity. The ethical work environment predicted moral distress intensity. These results reveal a difference between moral distress intensity and frequency and the importance of the environment to moral distress intensity.


Sainteks ◽  
2020 ◽  
Vol 16 (2) ◽  
Author(s):  
S. Widyaningsih ◽  
A. Istifaraswati

The mental impact of cancer on patients is often severe. Patients who have been recently diagnosed with breast cancer tend to experience depression, emotional stress, disappointment, and even despair which later can damage their psychological well-being. This study aims to describe Psychological Well-being among breast cancer patients.134 breast cancer patients were recruited at the Out Patient Department (OPD) of Tugurejo Hospital Semarang city, Indonesia. The data were collected using Ryff Scale Psychological Well-being (RSPWB) questionnaire. Most of the respondents were middle-aged, married, unemployed and had been diagnosed with early stadium of breast cancer. Results showed approximately half of the total respondents (n=64%, 47.8%) experiencing low levels of psychological well-being over the entire period of the sickness. Among four subscales of psychological well-being, “positive relationship with others” subscale was reported to be very low among those respondents. However, almost two thirds of respondents perceived a higher degree of self-acceptance and life purpose while experiencing the illness. Nurses and healthcare providers need to be aware of the importance of counseling service and family/patients support group to improve the relationship of patients with others.Keywords: psychological well-being, breast cancer


Development ◽  
2001 ◽  
Vol 128 (1) ◽  
pp. 125-135 ◽  
Author(s):  
J.F. Reiter ◽  
Y. Kikuchi ◽  
D.Y. Stainier

Previous studies have indicated that gata5, a zinc-finger transcription factor gene, is required for the development of the zebrafish gut tube. Here, we show that gata5 mutants also display defects in the development of other endodermal organs such as the liver, pancreas, thyroid and thymus. gata5 is expressed in the endodermal progenitors from late blastula stages, suggesting that it functions early during endoderm development. We indeed find that during gastrulation stages, gata5 mutants form fewer endodermal cells than their wild-type siblings. In addition, the endodermal cells that form in gata5 mutants appear to express lower than wild-type levels of endodermal genes such as sox17 and axial/foxA2. Conversely, overexpression of gata5 leads to expanded endodermal gene expression. These data indicate that Gata5 is involved both in the generation of endodermal cells at late blastula stages and in the maintenance of endodermal sox17 expression during gastrulation. We have also analyzed the relationship of Gata5 to other factors involved in endoderm formation. Using complementary mutant and overexpression analyses, we show that Gata5 regulates endoderm formation in cooperation with the Mix-type transcription factor Bon, that Gata5 and Bon function downstream of Nodal signaling, and that cas function is usually required for the activity of Gata5 in endoderm formation. Finally, we show that fau/gata5, bon and cas exhibit dominant genetic interactions providing additional support that they function in the same pathway. Together, these data demonstrate that Gata5 plays multiple roles in endoderm development in zebrafish, and position Gata5 relative to other regulators of endoderm formation.


Development ◽  
1973 ◽  
Vol 29 (3) ◽  
pp. 647-661
Author(s):  
C. K. Leach ◽  
J. M. Ashworth ◽  
D. R. Garrod

The behaviour, during the multicellular phase of the life-cycle, of amoebae of Dictyostelium discoideum grown in different media is described. Amoebal populations were marked by growth-temperature-sensitive genetic lesions which do not interfere with developmental phenomena. The fate of cell populations was determined by measuring the relative number of mutant and wild-type cells at various stages in the life-cycle. Cells sort out during development in such a way that they may be ordered in a sequence in which those given early in the following list preferentially appear in the spore population when mixed with those given later in the list: cells grown in axenic medium + 86 mm glucose and harvested when in the exponential phase of growth; cells grown in axenic medium and harvested when in the exponential phase of growth; cells grown on bacteria and harvested when in the exponential phase of growth; cells grown in axenic medium + 86 mM glucose and harvested when in the stationary phase of growth. Chemotactic aggregation and grex migration are not essential for sorting-out to occur but, in the normal life-cycle, the cells of a grex formed from amoebae grown in different media have sorted out anteroposteriorly. The relationship between this sorting out behaviour and the mechanism of pattern formation in fruiting-body morphogenesis is discussed. Differences in density of the amoebae cannot account for the sorting out predispositions we observe.


1985 ◽  
Vol 5 (7) ◽  
pp. 1772-1779
Author(s):  
M A Snyder ◽  
J M Bishop ◽  
J P McGrath ◽  
A D Levinson

We constructed a mutant, called RSV-SF2, at the ATP-binding site of pp60v-src. In this mutant, lysine-295 is replaced with methionine. SF2 pp60v-src was found to have a half-life similar to that of wild-type pp60v-src and was localized in the membranous fraction of the cell. Rat cells expressing SF2 pp60v-src were morphologically untransformed and do not form tumors. The SF2 pp60v-src isolated from these cells lacked kinase activity with either specific immunoglobulin or other substrates, and expression of SF2 pp60v-src failed to cause an increase of total phosphotyrosine in the proteins of infected cells. Wild-type pp60v-src was phosphorylated on serine and tyrosine in infected cells, and the analogous phosphorylations could also be carried out in vitro. Phosphorylation of serine was catalyzed by a cyclic AMP-dependent protein kinase, and phosphorylation of tyrosine was perhaps catalyzed by pp60v-src itself. By contrast, SF2 pp60v-src could not be phosphorylated on serine or tyrosine either in infected cells or in vitro. These findings strengthen the belief that the phosphotransferase activity of pp60v-src is required for neoplastic transformation by the protein and suggest that the binding of ATP to pp60v-src elicits an allosteric change required for phosphorylation of serine in the protein.


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