Search results for "urea"

Guaianolides and lignans from the aerial parts of Centaurea ptosimopappa.

2006

The genus Centaurea L. (Asteraceae, tribe Cardueae, subtribe Centaureinae) comprises ca. 600 species distributed in Asia, Europa, North Africa and America (Hickey and King, 1981; Heywood, 1979). Turkish flora numbers 187 species, 114 of which being endemic (Davis, 1975; Davis et al., 1988; Wagenitz et al., 1988; Guner et al., 2000; Duran and Duman, 2000; Turkoglu et al., 2003). Centaurea ptosimopappa Hayek is an endemic species distributed in the Mediterranean and South-Eastern Anatolian regions of Turkey; widespread and locally frequent in the Amanos and Casus mountains (Davis, 1975; Reeves and Adiguzel, 2004). Aerial parts of C. ptosimopappa were collected in Hatay, the Amanos Mountain ab…

La mediazione domanda offerta di lavoro ai tempi del Covid

2021

In this paper we face the trade off between labour demand and supply for graduates in the Covid Era.

Flow cytometry, sorting and immunocharacterization with proliferating cell nuclear antigen of cycling and non-cycling cells in synchronized pea root …

1997

In the 3-d-old 2-mm root tip of Pisum sativum L. cv. Lincoln the percentage of actively proliferating cells is estimated to be 70%. The remaining cells are non-cycling and arrested with 2C and 4C DNA content in G0 and in G2Q, respectively. In this work we studied the kinetic significance of these quiescent cells, using the sorting capabilities of flow cytometry and immunofluorescence techniques to detect the proliferation marker PCNA (proliferating cell nuclear antigen) inside cells within the different cell-cycle compartments. While in animal cells, PCNA is present at a high level only in actively proliferating cells, in 3-d-old pea root tips 95% of the cells are PCNA-positive. After flow …

Synthesis of huge macrocycles using two calix[4]arenes as templates.

2005

Macrocycles with up to 100 atoms have been synthesised using two calix[4]arenes as templates: first, (3,5-dialkenyloxy)phenyl groups are attached to the wide rim of a calix[4]arene via urea links, then the alkenyl groups are connected via a metathesis reaction using a tetratosylurea calix[4]arene for their correct prearrangement and finally the urea functions are cleaved to detach the newly formed macrocycles.

Xrcc2 deficiency sensitizes cells to apoptosis by MNNG and the alkylating anticancer drugs temozolomide, fotemustine and mafosfamide

2006

DNA double-strand breaks (DSBs) are potent killing lesions, and inefficient repair of DSBs does not only lead to cell death but also to genomic instability and tumorigenesis. DSBs are repaired by non-homologous end-joining and homologous recombination (HR). A key player in HR is Xrcc2, a Rad51-like protein. Cells deficient in Xrcc2 are hypersensitive to X-rays and mitomycin C and display increased chromosomal aberration frequencies. In order to elucidate the role of Xrcc2 in resistance to anticancer drugs, we compared Xrcc2 knockout (Xrcc2-/-) mouse embryonic fibroblasts with the corresponding isogenic wild-type and Xrcc2 complemented knockout cells. We show that Xrcc2-/- cells are hypersen…

Inhibition of O6-Methylguanine-DNA Methyltransferase by Glucose-Conjugated Inhibitors: Comparison with Nonconjugated Inhibitors and Effect on Fotemus…

2004

The DNA repair protein O(6)-methylguanine-DNA methyltransferase (MGMT) is an important suicide enzyme involved in the defense against O(6)-alkylating mutagens. It also plays a role in the resistance of tumors to anticancer drugs targeting the O(6)-position of guanine, such as temozolomide and fotemustine. Several potent MGMT inhibitors have been developed sensitizing cells to O(6)-alkylating agents. Aimed at targeting MGMT inhibitors to tumor cells, we synthesized MGMT inhibitory compounds conjugated with glucose to improve uptake in tumor cells. Here, we compared O(6)-benzylguanine, O(6)-2-fluoropyridinylmethylguanine (O(6)FPG), O(6)-3-iodobenzylguanine, O(6)-4-bromothenylguanine, and O(6)…

2021

The genus Centaurea is recognized in folk medicine for anti-inflammatory, anti-itch, antitussive, purgative, astringent, and tonic activities. To study the chemical determinant for antimicrobial activity essential oils (EOs), five Centaurea species were analyzed including: C. scoparia, C. calcitrapa, C. glomerata, C. lipii and C. alexandrina. Conventional hydro-distillation (HD) and microwave-assisted extraction (MAE), as new green technologies, were compared for the extraction of essential oils. GC/MS analysis identified 120 EOs including mostly terpenoid except from C. lipii and C. alexandrina in which nonterpenoids were the major constituents. Major terpenoids included spathulenol, caryo…

Milk production and physiological traits of ewes and goats housed indoor or grazing at different daily timing in summer

2009

During a 6 week trial in summer, 3 homogeneous groups, each consisting of 5 Comisana ewes and 5 Rossa Mediterranea goats, grazed watered forage resources during day (D) or night (N), or were housed indoor and supplied with mowed herbage (H). Maximum THI peaked at 94 at the end of July, and was almost constantly higher of 80. Milk yield was higher in N than in D and H goats, whereas N ewes produced more milk than H group, but their milk yield was higher than D ewes only in the period with the highest THI values. The lower urea in N goat milk, and the higher casein in N ewe milk, seem to indicate a better efficiency in dietary nitrogen utilization of night grazing animals. N ewes showed lower…

Relationships between dietary factors and milk urea nitrogen level in goats grazing herbaceous pasture

2008

This investigation aimed to individuate the dietary factors affecting the milk urea nitrogen (MUN) concentration in goats grazing herbaceous pasture and, particularly, to verify the relationship linking the diet crude protein (CP) content to MUN. A total of 205 individual observations regarding dietary and milk variables of 37 Girgentana goats involved in two experiments were used. Goats, averaging 154±14 days in milk and 38.1±5.4 kg of live weight, grazed on swards and received 500 g/d of barley meal. Sward biomass, herbage selected by goats and individual milk yield were measured and sampled weekly. The herbage intake and diet digestibility were estimated by the n-alkane met…

DINAMICA DEI NITRATI E MINERALIZZAZIONE DEL CARBONIO IN UN SUOLO A VIGNETO IN AMBIENTE SEMIARIDO

2013

La gestione agronomica del vigneto in ambiente semiarido è spesso caratterizzata sia dalle frequenti lavorazioni del suolo che dall’apporto di fertilizzanti inorganici, in particolare azotati. Tale gestione, congiuntamente alle caratteristiche pedo-climatiche tipiche dell’ambiente semiarido, causa spesso un depauperamento del contenuto in sostanza organica del suolo e, dall’altro lato, incrementa il rischio di dilavamento di nitrati dal suolo. Al fine di controbilanciare tali effetti indesiderati, sono state introdotte nella gestione del suolo a vigneto tecniche di agricoltura conservativa, quali l’introduzione delle cover crops e l’interramento, previa trinciatura, dei residui di potatura,…