Excisionase (Xis) is an accessory protein that is required for the site-specific excision reaction of the coliphages HK022 and λ. Xis binds in a strong cooperative manner to two tandem binding sites ...(X1 and X2) located on the P arm of the attachment (
att) sites on the phage genome. As a result of crosslinking experiments in vivo and in vitro of Xis-overexpressing cells, by gel filtration of purified Xis and by FRET analyses we show that Xis monomers of HK022 interact and form dimers that are not dependent on the single Cys residue of the protein and on the presence of DNA. The formation of the dimers may explain the strong binding cooperativity of Xis to its sites on DNA.
We recently re-inbred the original colony of SBH-SBN rats, a model of salt-induced hypertension. In the course of phenotyping the new colony, SBH/y were found to excrete a lower urine flow with a ...higher urine osmolality than SBN/y. Thus disparate water handling between the substrains, a phenotype characteristic of the original colony, was retained throughout the selection procedure and transmitted down the generations to the new colony. As water handling is directly linked to arginine vasopressin (AVP) and in view of potential linkage of this phenotype to salt sensitivity or resistance in terms of the development of hypertension, the AVP axis was further investigated in the new substrains. Basal plasma AVP levels were higher in SBH/y (2.86 +/- 0.22 pg/ml; n = 10) than in SBN/y (1.98 +/- 0.11 pg/ml; n = 10, P < 0.05). Water deprivation for 48 h increased plasma AVP levels severalfold in both substrains to similar levels. Niravoline, a kappa receptor agonist that inhibits central release of AVP, produced at 0.6 and 0.9 mg/kg a more profound diuretic effect in SBN/y than in SBH/y, suggesting greater pituitary release of AVP into the circulation of SBH/y. AVP mRNA contents were compared in SBH/y and SBN/y rats in whole hypothalamic extracts and in the supraoptic (SON) and paraventricular (PVN) nuclei by RNA protection assay. Under basal conditions, AVP mRNA content (in ng) in the hypothalamus of SBH/y was 4.48 +/- 0.52 (n = 29) and of SBN/y was 3.13 +/- 0.35 (n = 30), P < 0.05; in the SON of SBH/y, AVP mRNA content was 3.62 +/- 0.44 (n = 11) and of SBN/y was 2.21 +/- 0.54 (n = 10), P < 0.05; in the PVN of SBH/y, AVP mRNA content was 0.78 +/- 0.16 (n = 9) and of SBN/y was 0.77 +/- 0.13 (n = 11, not significant). Thus the differences in hypothalamic AVP mRNA were primarily in the SON. Water deprivation as well as salt loading (8% NaCl) induced a significant elevation in AVP mRNA content in SBN/y but a blunted response in SBH/y. These data suggest that there is genetically transmitted enhanced hypothalamic expression of the AVP gene in SBH/y compared with SBN/y which results, under basal conditions, in greater pituitary release of AVP, in higher plasma AVP levels, and in increased renal concentrating activity. As AVP has been implicated in various forms of hypertension, these findings render AVP a candidate gene for salt sensitivity or resistance in the Sabra rat model of hypertension.
The purpose of this study is to compare the baseline psychological distress and symptom profile of women undergoing either medical (with mifepristone) or surgical pregnancy termination and the ...psychological outcome 2 weeks after the procedure.
Women (
n=200) given free choice of pregnancy termination method, either medical or surgical, were assessed before pregnancy termination by a demographic questionnaire including questions regarding the choice of the method of pregnancy termination, the Brief Symptom Inventory (BSI), the Spielberger State Anxiety questionnaire and the Rotter Locus of Control Scale. Two weeks after the procedure, the BSI and Spielberger questionnaires were repeated.
Women with a smaller number of past pregnancies tended to choose the medical procedure. Reasons for choosing the medical procedure were fear of surgery, anesthesia and of future fertility difficulties. Prior to the procedure, the “medical group” had significantly higher levels of obsessive–compulsive symptoms, guilt and BSI general symptom index score, and a trend for higher interpersonal sensitivity and paranoid ideation. Postprocedure, both groups showed significant decline in anxiety levels and did not differ on most symptom parameters.
Women who chose to have a medical termination are marginally more symptomatic before the procedure than women choosing surgical termination. However, both methods of pregnancy termination resulted in significant reduction in preabortion psychological distress level.
The study examined respective perceptions of justice within leader-employee dyads. Questionnaires were administered to 152 such dyads in a variety of organizational settings. Employees’ perceptions ...of interactional justice were found to mediate the relationship between the leader’s evaluation of the relationship (i.e., equity and the quality of the relationship), on the one hand, and the employee’s evaluation of the relationship and perception of procedural justice, on the other. Both procedural justice and interactional justice were related to job satisfaction through a partial mediation of the employee’s perception of the quality of the relationship. The results are discussed in regard to the effect of the leader-member social exchange on perceptions of justice
The integrase encoded by the lambdoid phage HK022 (Int-HK022) resembles its coliphage λ counterpart (Int-λ) in the roles of the cognate DNA arm binding sites and in controlling the direction of the ...reaction. We show here that within mammalian cells, Int-HK022 does not exhibit such a control. Rather, Int-HK022 recombined between all ten possible pairwise att site combinations, including attB × attB that was more effective than the conventional integrative attP × attB reaction. We further show that Int-HK022 depends on the accessory integration host factor (IHF) protein considerably less than Int-λ and exhibits stronger binding affinity to the att core. These differences explain why wild-type Int-HK022 is active in mammalian cells whereas Int-λ is active there only as an IHF-independent mutant.
The integrase (Int) protein of coliphage HK022 catalyzes the site-specific integration and excision of the phage into and from its Escherichia coli host chromosome. Int expressed from a plasmid in ...COS1 monkey cells is localized in the nucleus, as is a fusion protein between Int and the green fluorescent protein (GFP). Mutation analysis of the GFP–Int fusion has revealed in Int two regions of positively charged amino acid residues that cooperate in the nuclear localization. One region harbors residues Arg90 and Arg93. The other, which spans residues 307–340 belongs to the catalytic domain of Int, is rich in basic residues and is strongly conserved within the Int protein family. Being localized in the nucleus renders Int of HK022 as a potential recombinase for site-specific gene manipulations in mammals.
Question: We studied the interactive effects of grazing and dwarf shrub cover on the structure of a highly diverse annual plant community. Location: Mediterranean, semi-arid shrubland in the Northern ...Negev desert, Israel. Methods: Variation in the biomass and plant density of annual species in the shrub and open patches was monitored during four years, inside and outside exclosures protected from sheep grazing, in two contrasting topographic sites: north and south-facing slopes that differed in their dominant dwarf shrubs species: Sarcopoterium spinosus and Corydothymus capitatus, respectively. Results: Above-ground biomass, density and richness of annual species were lower under the canopy of both shrub species compared to the adjacent open patches in the absence of grazing. Grazing reduced the biomass of annuals in open patches of both topographic sites, but not in the shrub patches. On the north-facing slope, grazing also reduced plant density and richness in the open patches, but increased plant density in the shrub patches. At the species level, various response patterns to the combined effects of grazing and patch type were exhibited by different annuals. Protection against the direct impacts of grazing by shrub cover as well as species-specific interactions between shrubs and annuals were observed. A conceptual mechanistic model explaining these interactions is proposed. Conclusion: In semi-arid Mediterranean shrublands grazing and dwarf shrub cover interact in shaping the structure of the annual plant community through (1) direct impacts of grazing restricted to the open patches, (2) species-specific facilitation/interference occurring in the shrub patches and (3) subsequent further processes occurring among the interconnected shrub and open patches mediated through variation in seed flows between patches. Nomenclature: Feinbrun-Dothan & Danin 1998.
Primary osteosarcomas of the bladder account for about 0.04% of bladder neoplasms. Most of the patients in the literature expired within 6 months and, in almost all of the cases in the literature, ...radical cystectomy with postoperative chemotherapy was the treatment choice. A 79-year-old gentleman presented with gross hematuria. Cystoscopy demonstrated a 2- to 3-cm tumour along the lateral wall of the bladder. The tumour was resected incompletely via initial transurethral resection of bladder tumour (TURBT), and a second TURBT was subsequently performed to fully resect the residual mass. Surgical pathology from these 2 resections revealed osteosarcoma with invasion into the muscularis propria. A cystoprostatectomy was performed and final pathologic specimen revealed high-grade CIS without evidence of residual osteosarcoma. Postoperatively, the patient did not receive chemotherapy or radiation and currently remains disease-free 2 years post-radical cystectomy. Only 33 well-documented cases of primary osteosarcoma of the bladder have been reported to date. However, there are only 3 cases in which TURBT resulted in complete resection.
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