NISCAIR Online Periodicals Repository Collection: IJEB Vol.44(04) [April 2006]

Effect of UV-B on photosynthesis, membrane lipids and MAAs in marine cyanobacterium, Phormidium corium (Agardh) Gomont

Wed, 29 Mar 2006 22:58:59 GMT

Title: Effect of UV-B on photosynthesis, membrane lipids and MAAs in marine cyanobacterium, Phormidium corium (Agardh) Gomont

Authors: Bhandari, Rupali; Sharma, Prabhat Kumar

Abstract: UV-B radiation (0.8±0.1 mW cm^-2) and UV-B radiation supplemented with low intensity PAR (~80 m mol m^-2s^-1) affected photosynthesis at the level of antenna system as well as PS II reaction centre (F_o and F_m declined) in Phormidium corium (Agardh) Gomont. UV-B radiation resulted in decline in sugar content, peroxidation of membrane lipids as well as quantitative and qualitative changes in phosphoglycolipids and neutral lipids. Fatty acid profile did not show any qualitative changes due to the treatment, however, UV-B supplemented with low PAR resulted in slightly higher level of unsaturation. P. corium synthesized MAAs in response to UV-B. Quantity of MAAs increased when UV-B treatment was supplemented with low level PAR.

Page(s): 330-335

Siderophores of halophilic archaea and their chemical characterization

Wed, 29 Mar 2006 22:58:59 GMT

Title: Siderophores of halophilic archaea and their chemical characterization

Authors: Dave, B P; Anshuman, Kena; Hajela, Puja

Abstract: Nine halophilic archaea viz., Halobacterium salinarum, Halobacterium sp.1, Halobacterium sp.2, Halobaculum sp., Halococcus saccharolyticus, Halorubrum saccharovorum, Haloterrigena turkmenica, Halogeometricum sp. and Natrialba sp. isolated from marine salterns around Bhavnagar coast were screened for siderophore production. Five isolates viz., Halococcus saccharolyticus, Halorubrum saccharovorum, Haloterrigena turkmenica, Halogeometricum sp. and Natrialba sp. produced siderophores as evidenced by positive reaction in FeCl₃ test, CAS assay and CAS agar plate test. Determination of chemical nature of siderophores by chemical assays and bioassays identified them as carboxylates. Quantification of siderophores indicated Halorubrum saccharovorum to be the maximum siderophore producer (2.62 RE mg/ml) and Halococcus saccharolyticus to be the least (1.33 RE mg/ml). The present study is the first report on siderophore production in Indian haloarchaeal strains. Mechanism of iron assimilation in four non-siderophore isolates still needs to be investigated further.

Page(s): 340-344

Effect of plantain banana on gastric ulceration in NIDDM rats: Role of gastric mucosal glycoproteins, cell proliferation, antioxidants and free radicals

Wed, 29 Mar 2006 22:58:59 GMT

Title: Effect of plantain banana on gastric ulceration in NIDDM rats: Role of gastric mucosal glycoproteins, cell proliferation, antioxidants and free radicals

Authors: Kumar, M Mohan; Joshi, M C; Prabha, T; Dorababu, M; Goel, R K

Abstract: Methanolic extract of Musa sapientum var. Paradisiaca (MSE, 100 mg/kg) was studied for its antiulcer and mucosal defensive factors in normal and non-insulin dependent diabetes mellitus (NIDDM) rats. NIDDM was induced by administering streptozotocin (STZ, 70 mg/kg, ip) to 5 days old rat pups. The animals showing blood glucose level > 140mg/dL after 12 weeks of STZ administration were considered as NIDDM positive. Effects of MSE were compared with known ulcer protective drug, sucralfate (SFT, 500 mg/kg) and anti-diabetic drug glibenclamide (GLC, 0.6 mg/kg) when administered orally, once daily for 6 days against gastric ulcers (GU) induced by cold-restraint stress (CRS) and ethanol and subsequent changes in gastric mucosal glycoproteins, cell proliferation, free radicals (lipid peroxidation and nitric oxide) and anti-oxidants enzymes (super oxide dismutase and catalase) and glutathione (GSH) levels. MSE showed better ulcer protective effect in NIDDM rats compared with SFT and GLC in CRS-induced GU. NIDDM caused a significant decrease in gastric mucosal glycoprotein level without having any effect on cell proliferation. However, all the test drugs reversed the decrease in glycoprotein level in NIDDM rats, but cell proliferation was enhanced in case of MSE alone. Both CRS or NIDDM as such enhanced gastric mucosal LPO, NO and SOD, but decreased CAT levels while CRS plus NIDDM rats caused further increase in LPO and NO level without causing any further changes in SOD and CAT level. MSE pretreatment showed reversal in the levels of all the above parameters better than GLC. Ethanol caused a decrease in glutathione level which was further reduced in NIDDM-ethanol rats. MSE reversed the above changes significantly in both normal as well as in NIDDM rats, while GLC reversed it only in NIDDM rats. However, SFT was ineffective in reversing the changes induced by CRS or ethanol or when given in NIDDM-CRS or NIDDM-ethanol rats. The results indicated that the ulcer protective effect of MSE could be due to its predominant effect on mucosal glycoprotein, cell proliferation, free radicals and antioxidant systems.

Page(s): 292-299

Hepatoprotective activity of Psidium guajava Linn. leaf extract

Wed, 29 Mar 2006 22:58:59 GMT

Title: Hepatoprotective activity of Psidium guajava Linn. leaf extract

Authors: Roy, Chanchal K; Kamath, Jagadish V; Asad, Mohammed

Abstract: The study was designed to evaluate the hepatoprotective activity of P. guajava in acute experimental liver injury induced by carbon tetrachloride, paracetamol or thioacetamide and chronic liver damage induced by carbon tetrachloride. The effects observed were compared with a known hepatoprotective agent, silymarin. In the acute liver damage induced by different hepatotoxins, P. guajava leaf extracts (250 and 500mg/kg, po) significantly reduced the elevated serum levels of aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase and bilirubin. The higher dose of the extract (500 mg/kg, po) prevented the increase in liver weight when compared to hepatoxin treated control, while the lower dose was ineffective except in the paracetamol induced liver damage. In the chronic liver injury induced by carbon tetrachloride, the higher dose (500 mg/kg, po) of P. guajava leaf extract was found to be more effective than the lower dose (250 mg/kg, po). Histological examination of the liver tissues supported the hepatoprotection. It is concluded that the aqueous extract of leaves of guava plant possesses good hepatoprotective activity.

Page(s): 305-311