Mechanism and sterochemistry of vinyl group formation in haem biosynthesis

1972 ◽  
pp. 1263 ◽  
Author(s):  
Z. Zaman ◽  
M. M. Abboud ◽  
M. Akhtar
Keyword(s):  
Group Formation ◽  
Haem Biosynthesis ◽  
Vinyl Group

scholarly journals Anaerobic and aerobic coproporphyrinogen III oxidases of Rhodopseudomonas spheroides. Mechanism and stereochemistry of vinyl group formation

1983 ◽  
Vol 209 (3) ◽  
pp. 709-718 ◽  
Author(s):  
J S Seehra ◽  
P M Jordan ◽  
M Akhtar
Keyword(s):  
Hydrogen Atom ◽  
Group Formation ◽  
Side Chains ◽  
Improved Method ◽  
Conversion Formula ◽  
Coproporphyrinogen Iii Oxidase ◽  
Rhodopseudomonas Spheroides ◽  
Vinyl Group

An improved method for the preparation of various species of porphobilinogen stereospecifically labelled with 3H in the side chains (at C-6, C-7 and C-8) is described. These labelled samples were used to study the mechanism and stereochemistry of anaerobic as well as aerobic coproporphyrinogen III oxidase of light-grown Rhodopseudomonas spheroides. It was shown that both the oxidases catalyse the conversion of the propionate side chains of coproporphyrinogen III into the vinyl groups of protoporphyrinogen IX, (formula; see text) with the labilization of the pro-S-hydrogen atom at the beta-position. These results are similar to those previously recorded for such conversions in animal and plant systems. In the light of the cumulative information available to date, mechanisms for the conversion, (formula; see text) are discussed and doubt is cast on the participation of hydroxylated intermediates in the process.

Sulfhydryl bond formation is a prerequisite for proper cycling of centrosomes and chromosomes in mammalian tissue culture cells

1993 ◽  
Vol 51 ◽  
pp. 342-343
Author(s):  
Heide Schatten ◽  
Neidhard Paweletz ◽  
Ron Balczon
Keyword(s):  
Tissue Culture ◽  
Cell Cycle Progression ◽  
Group Formation ◽  
Sulfhydryl Group ◽  
Mammalian Tissue ◽  
Mitotic Chromosomes ◽  
Microtubule Network ◽  
Culture Cells ◽  
Tissue Culture Cells ◽  
Transmission Electron

To study the role of sulfhydryl group formation during cell cycle progression, mammalian tissue culture cells (PTK2) were exposed to 100¼M 2-mercaptoethanol for 2 to 6 h during their exponential phase of growth. The effects of 2-mercaptoethanol on centrosomes, chromosomes, microtubules, membranes and intermediate filaments were analyzed by transmission electron microscopy (TEM) and by immunofluorescence microscopy (IFM) methods using a human autoimmune antibody directed against centrosomes (SPJ), and a mouse monoclonal antibody directed against tubulin (E7). Chromosomes were affected most by this treatment: premature chromosome condensation was detected in interphase nuclei, and the structure in mitotic chromosomes was altered compared to control cells. This would support previous findings in dividing sea urchin cells in which chromosomes are arrested at metaphase while the centrosome splitting cycle continues. It might also support findings that certairt-sulfhydryl-blocking agents block cyclin destruction. The organization of the microtubule network was scattered probably due to a looser organization of centrosomal material at the interphase centers and at the mitotic poles.

Promoting Women’s Entrepreneurship in Lebanon: Enhancing Empowerment or Vulnerability?

1970 ◽  
pp. 39-47
Author(s):  
Nabil Abdo
Keyword(s):  
Low Income ◽  
Women Entrepreneurs ◽  
Group Formation ◽  
Business Groups ◽  
Economic Empowerment ◽  
Sustainable Livelihood ◽  
Business Skills ◽  
Palestinian Women ◽  
Support Organizations ◽  
And Training

The International Labour Organization in Beirut has been running a project in the Palestinian Camps of Nahr El Bared and Ein El Helweh entitled “Palestinian Women Economic Empowerment Initiative”. The project started in 2011 and targets lowincome Palestinian women entrepreneurs through a threefold strategy: giving out loans and grants to women business groups in order to expand their businesses; training women entrepreneurs to enhance their business skills; and building the capacity of support organizations in order to improve business development services for women entrepreneurs and training them to be formally certified to deliver business group formation training. The project builds on the potential of business groups in assuring the protection of Palestinian women entrepreneurs from risks through resilience, pooling of resources, and collective voice. The objectives are to assure a sustainable livelihood for Palestinian women entrepreneurs through supporting them in expanding their businesses beyond survivalist low-income activities

Beautiful or White? Discrimination in Group Formation

2008 ◽  
Author(s):  
Marco Castillo ◽  
Ragan Petrie ◽  
Maximo A. Torero
Keyword(s):  
Group Formation

scholarly journals The origins of the state: technology, cooperation and institutions

2020 ◽  
pp. 1-15
Author(s):  
Giacomo Benati ◽  
Carmine Guerriero
Keyword(s):  
Bronze Age ◽  
State Formation ◽  
Risk Sharing ◽  
Group Formation ◽  
Public Spending ◽  
Stable State ◽  
The State ◽  
State Institutions ◽  
Production Conditions ◽  
Alternative Theories

Abstract We develop a theory of state formation shedding light on the rise of the first stable state institutions in Bronze Age Mesopotamia. Our analysis suggests that the mix of adverse production conditions and unforeseen innovations pushed groups favored by old technologies to establish the state by granting political and property rights to powerless individuals endowed with new and complementary skills. Through these reforms, the elite convinced the nonelite that a sufficient part of the returns on joint investments would be shared via public spending and, thus, to cooperate and accumulate a culture of cooperation. Different from the main alternative theories, we stress that: (1) group formation is heavily shaped by unforeseen shocks to the returns on both risk-sharing and innovation; (2) complementarity in group-specific skills, and not violence, is key determinant of state formation; (3) military, merchant and, especially, religious ranks favored state formation and culture accumulation.

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