■ Abstract Apoptosis is a genetically programmed, morphologically distinct form of cell death that can be triggered by a variety of physiological and pathological stimuli. Studies performed over the past 10 years have demonstrated that proteases play critical roles in initiation and execution of this process. The caspases, a family of cysteine-dependent aspartate-directed proteases, are prominent among the death proteases. Caspases are synthesized as relatively inactive zymogens that become activated by scaffold-mediated transactivation or by cleavage via upstream proteases in an intracellular cascade. Regulation of caspase activation and activity occurs at several different levels: ( a) Zymogen gene transcription is regulated; ( b) antiapoptotic members of the Bcl-2 family and other cellular polypeptides block proximity-induced activation of certain procaspases; and ( c) certain cellular inhibitor of apoptosis proteins (cIAPs) can bind to and inhibit active caspases. Once activated, caspases cleave a variety of intracellular polypeptides, including major structural elements of the cytoplasm and nucleus, components of the DNA repair machinery, and a number of protein kinases. Collectively, these scissions disrupt survival pathways and disassemble important architectural components of the cell, contributing to the stereotypic morphological and biochemical changes that characterize apoptotic cell death.

Mammalian caspases: structure ,a ctivation ,s ubstrates, and functions during apoptosis

Since the first identification of renin by Tigerstedt and Bergmann in 1898, the renin-angiotensin system (RAS) has been extensively studied. The current view of the system is characterized by an increased complexity, as evidenced by the discovery of new functional components and pathways of the RAS. In recent years, the pathophysiological implications of the system have been the main focus of attention, and inhibitors of the RAS such as angiotensin-converting enzyme (ACE) inhibitors and angiotensin (ANG) II receptor blockers have become important clinical tools in the treatment of cardiovascular and renal diseases such as hypertension, heart failure, and diabetic nephropathy. Nevertheless, the tissue RAS also plays an important role in mediating diverse physiological functions. These focus not only on the classical actions of ANG on the cardiovascular system, namely, the maintenance of cardiovascular homeostasis, but also on other functions. Recently, the research efforts studying these noncardiovascular effects of the RAS have intensified, and a large body of data are now available to support the existence of numerous organ-based RAS exerting diverse physiological effects. ANG II has direct effects at the cellular level and can influence, for example, cell growth and differentiation, but also may play a role as a mediator of apoptosis. These universal paracrine and autocrine actions may be important in many organ systems and can mediate important physiological stimuli. Transgenic overexpression and knock-out strategies of RAS genes in animals have also shown a central functional role of the RAS in prenatal development. Taken together, these findings may become increasingly important in the study of organ physiology but also for a fresh look at the implications of these findings for organ pathophysiology.

Physiology of local renin-angiotensin systems.

Significance of biogenic amines to food safety and human health

Analysis of nitrite and nitrate in biological fluids by assays based on the Griess reaction: appraisal of the Griess reaction in the L-arginine/nitric oxide area of research.

A review of using Griess Reaction method to determine nitric oxide production in biological systems.

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Measurement of Nitric Oxide Production in Biological Systems by Using Griess Reaction Assay

Spectrophotometric Determination of Serum Nitrite and Nitrate by Copper–Cadmium Alloy

In chickens, high levels of dietary zinc cause molting, and the reproductive system undergoes complete remodeling concomitant to feather replacement. In the present study, the expression profiles of cytokines and chemokines were investigated in the ovary and oviduct of control hens and of hens induced to molt by zinc feeding. The zinc-induced feed-intake suppression, the changes in corticosterone levels, the immune cell populations in the reproductive tract, and the apoptosis of reproductive tissues were analyzed. The expression of mRNAs for interleukin-6 (IL-6), interferon-γ (IFN-γ), the avian ortholog of mammalian IL-8 (chCXCLi2), and a chicken MIP-1β-like chemokine (chCCLi2) in the ovary and of mRNAs for IL-1β, IL-6, IFN-γ, transforming growth factor-β2, chCXCLi2, and chCCLi2 in the oviduct were upregulated significantly during zinc-induced molting. A simultaneous feed-intake reduction was observed with higher expression of cytokines and chemokines. The results of the present investigation also suggested that the upregulation of corticosterone was closely associated with the increased expression of cytokines and chemokines. An increase in apoptosis within reproductive tissue during tissue regression was also noted. We had previously observed the upregulation of these cytokines expression in an earlier study (molting by feed withdrawal). However, the pattern and the level of expression were different among these two methods. These findings indicate that cytokines might be a common mediator of tissue regression during molting induced by diverse methods, although the pattern of induction is different. Thus, a high dose of dietary zinc seems to induce reproductive regression via the upregulation of cytokines and chemokines, the suppression of feed intake, and the increase in serum corticosterone, resulting finally in the apoptosis of reproductive tissues.

High doses of dietary zinc induce cytokines, chemokines, and apoptosis in reproductive tissues during regression

Cytokines in reproductive remodeling of molting White Leghorn hens.

1. This experiment was to investigate the effects of increasing dietary vitamin E on physical and biochemical characteristics of semen in Indian reared Kadaknath (KN) cockerels. DL-alpha-Tocopherol acetate was used as the source of vitamin E. 2. A total of 135 one-day-old male KN chicks were randomly selected and divided into 9 groups with 15 chicks in each group (3 dietary treatments x 3 replicates). 3. The basal diet contained 15 IU (10 mg) vitamin E/kg and the two experimental diets were supplemented with 150 IU (100 mg) and 300 IU (200 mg) vitamin E/kg (diets T(2) and T(3), respectively). 4. Physical characteristics in terms of semen volume, sperm concentration, sperm motility and percentage live sperm did not differ significantly, whereas proportion of abnormal and dead spermatozoa were significantly lower and fertility higher in the T(2) group. 5. Biochemical characteristics in term of quantities of protein and nitric oxide (NO) did not differ significantly, whereas the quantity of glucose, acid phosphatase (ACP) and vitamin E were significantly higher in the T(2) group. 6. In contrast, the quantities of alkaline phosphatase (ALP), glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT) were significantly lower in T(2) group and higher in the T(1) (control) group. 7. From this study it can be concluded that moderate supplementation of dietary vitamin E may be beneficial for physical and biochemical characteristics of semen in Indian reared KN cock.

Jag Mohan

Papers

Spectrophotometric Determination of Serum Nitrite and Nitrate by Copper–Cadmium Alloy

High doses of dietary zinc induce cytokines, chemokines, and apoptosis in reproductive tissues during regression

Cytokines in reproductive remodeling of molting White Leghorn hens.

Effect of higher dietary vitamin E concentrations on physical and biochemical characteristics of semen in Kadaknath cockerels

Effects of hemicastration and castration on foam production and its relationship with fertility in male Japanese quail.