Isolation of cold stress-responsive genes from Lepidium latifolium by suppressive subtraction hybridization

Suppression subtraction hybridization (SSH) libraries were constructed from RNA isolated from leaves of control and cold stress-induced Lepidium latifolium, a cold-tolerant plant species from high altitudes for isolation of cold-responsive genes. A total of 500 clones were obtained from the cold stress library. Dot blot expression analysis identified 157 clones that were upregulated and 75 that were downregulated during cold stress. These clones selected on the basis of their expression patterns on dot blot were sequenced. As much as 27 and 17 genes were identified from the forward and reverse libraries, respectively. The genes identified revealed homology with genes involved in diverse processes such as gene regulation/signaling, photosynthesis, DNA damage repair protein, pathogenesis-related protein, senescence-associated proteins and proteins with unknown functions.     

Phytoestrogenic effects of black tea extract (Camellia sinensis) in an oophorectomized rat (Rattus norvegicus) model of osteoporosis

The adverse side effects of currently available anti-osteoporotic agents warrant the search for compounds with less toxic effects. In this study, we assessed the phytoestrogenic potentiality of whole aqueous extract of black tea (BTE) in a bilaterally oophorectomized rat model (2.5%, 1 ml/100 g body weight/day for 28 days). Although the supplementation was given for 28 days but, sign of revival of copulation period (estrous stage) from non-receptive diestrous stage was first noticed after 21 days of BTE supplementation in bilaterally oophorectomized rats. This was accompanied by a significant increase in serum estradiol level. To test whether this increase in serum estradiol level could have an influence upon the oophorectomy-induced damage of bone, we assessed marker parameters of bone resorption and osteoclastic activity (tartrate-resistant acid phosphatase), collagen degradation (urinary hydroxyproline), bone loss (bone ash mineral content) and bone breaking strength (bone density). Results indicated that increase in serum estradiol level after BTE supplementation could significantly diminish oophorectomy-induced decaying changes in bone. This study proposes that aqueous BTE may be assessed as a phytoestrogenic compound for prevention against estrogen deficiency-related osteoporotic damages.     

Type II phosphatidylinositol 4-kinase(s) in cell signaling cascades

Phosphorylated derivatives of phosphatidylinositol (PtdIns) are key components of many signaling cascades. Many isoforms of PtdIns kinases, PtdIns phosphate kinases and phosphatases use these lipids in amazing networks of signaling cascades that are yet to be understood fully. PtdIns 4-kinase(s) phosphorylates PtdIns at the 4th -OH position of inositol head group and are classified in to type II and III PtdIns 4-kinases. While type III PtdIns 4-kinases are implicated in vesicular trafficking, type II PtdIns 4-kinases are suggested to play a role in cell signaling, cytoskeletal rearrangements, cell motility and in microbial pathogenicity. This paper reviews the role of type II PtdIns 4-kinases in cell signaling cascades in health and disease.     

Ultrastructure of the corpus luteum of antarctic seals during pregnancy

Summary The fine structure of granulosa lutein cells from three crabeater seals, Lobodon carcinophagus, and two leopard seals, Hydrurga leptonyx, has been studied from early through mid-pregnancy. Analysis of the arrangement and modifications of the cytoplasmic organelles and inclusions has revealed three types of lutein cells throughout the corpus. Type I cell typically possesses a central nucleus and cytoplasm containing very large amounts of smooth and/or fenestrated endoplasmic cisternae which frequently extend from the juxta-nuclear to the periphery of the cell. Type II cell contains a central or eccentric nucleus, moderate amounts of peripheral, smooth and fenestrated cisternae which often form large and concentric membranous whorls, numerous mitochondria and small lipid droplets. Frequently these cells show polarity in the arrangement of the cytoplasmic organelles and inclusions. Type III cell contains predominant large lipid droplets, many mitochondria, and small amounts of smooth and fenestrated cisternae. In light microscopy the type I cell is evenly granular, while the type III cell is highly vacuolated. Type II cells have both granular and vacuolated conditions. Ultrastructural features of type I and II cells suggest that they probably secrete most of the steroids, whereas the primary role of the type III cells appear to be lipid storage.This research was supported by National Science Foundation, Grant No. 1325 from the Office of Antarctic Biology.