Indian Journal of Experimental Biology

 

Total visitors: 1,482  since 24-08-06

VOLUME 44

NUMBER 9

SEPTEMBER 2006

CODEN : IJEB (A6) 44(9) 679-772 (2006)

ISSN : 0019-5189

 

CONTENTS

 

Review Article

 

Genetic basis of HIV-1 resistance and susceptibility: An approach to understand correlation between human genes and HIV-1 infection

 

683

        Vijay Kumar, O Prakash, S Manpreet, G Sumedh & B Medhi

 

 

 

Papers

 

Differential role of MAP kinase isoforms in malachite green transformed Syrian hamster embryo fibroblasts in culture

 

693

        Bipasha Bose, Rekha R Gour, Leena Motiwale & K V K Rao

 

 

 

Neuroprotective effect of BDNF in young and aged 6-OHDA treated rat model of Parkinson disease

 

699

        Shalini Singh, Riyaz Ahmad, Deepti Mathur, Ravinder Kumar Sagar, Bal Krishana, Rajesh Arora & Rakesh Kumar Sharma

 

 

 

Long term excessive Zn–supplementation promotes metabolic syndrome-X in Wistar rats fed sucrose and fat rich semisynthetic diet

 

705

        S K Taneja, R Mandal & S Girhotra

 

 

 

Effect of AC II, a herbal formulation on radiation-induced immunosuppression in mice

719

        Sheeja T Tharakan, Girija Kuttan, Ramadasan Kuttan, M Kesavan, Sr Austin &
K Rajagopalan

 

 

 

Immunostimulatory effect of Tinospora cordifolia Miers leaf extract in Oreochromis mossambicus


726

        D Samuel Sudhakaran, P Srirekha, L D Devasree, S Premsingh  & R Dinakaran Michael

 

 

 

Cumulative antioxidant defense against oxidative challenge in galactose-induced cataractogenesis in Wistar rats

 

733

        T N Raju, C Sanat Kumar, V Rajani Kanth, B Venkata Ramana & P Uma Maheswara Reddy, P Suryanarayana & G Bhanuprakash Reddy

 

 

 

Evaluation of herbal coccidiostat ‘Coxynil’ in broiler

740

        N V Kurkure, S W Kolte, A G Bhandarkar & D R Kalorey

 

 

 

Biochemical effects of Nigella sativa L seeds in diabetic rats

745

        M Kaleem, D Kirmani, M Asif, Q Ahmed & Bilqees Bano

 

 

 

Prepatent detection of Fasciola gigantica infection in bovine calves using metacercarial antigen

 

749

        R Velusamy, B P Singh, S Ghosh, D Chandra, O K Raina, S C Gupta & A K Jayraw

 

 

 

Bioactivity of marine organisms: Part X - Screening of some marine fauna from the Indian coasts

 

754

        V Lakshmi , A K Goel, M N Srivastava & Ram Raghubir

 

 

Efficient protocols for in vitro regeneration of Pennisetum glaucum (L) Br.

757

        S Arockiasamy, S Sahaya Rani, S Ignacimuthu & G Melchias

 

 

In vitro propagation of threatened terrestrial orchid, Malaxis khasiana Soland ex. Swartz through immature seed culture

 

762

        Chitta Ranjan Deb & Temjensangba

 

 

 

Catalytic and regulatory properties of sulphur metabolizing enzymes in cyanobacterium Synechococcus elongatus PCC 7942

 

767

        Anuradha Jain, Deepti Verma & Divya Bagchi

 

 

 

Announcements

682

47th Annual Conference of Association of Microbiologists of India (AMI)

 

SFRR-India National Satellite Meeting and International Conference on Free Radicals in Clinical and Laboratory Medicine

 

 

 

Announcements

47th Annual Conference of Association of Microbiologists of India (AMI)

6-8 December 2006, Bhopal

 

Organized by the Department of Biotechnology, Barkatullah University, Bhopal, the theme of the conference is “Microbiology: The Challenges Ahead” focusing on the biotechnology based on live microorganisms relevant to all major areas of microbiology like, Microbial biotechnology, Industrial microbiology, Food microbiology, Microbial technologies for environmental management, Agricultural microbiology, Medical and veterinary biotechnology, and Patents & IPR. The conference will have following sessions: Plant-microbe interaction; Microbial community systematics & evolution; Microbial genomics & proteomics; Environmental bioremediation; Bioenergy & biocatalysts; Biomolecules; Marine microbes & their potential; Food-borne infections, and Newer vaccines & diagnostics. For details, please contact: Dr. Anil Prakash, Organizing Secretary, Dept. of Biotechnology & Bioinformatics Centre, Barkatullah University, Bhopal 462026, India. Telephone: (O): +91-755-2677748, 2677749; Fax: +91-755-2485656, 2581835. email: ami2006@rediffmail.com; ami47_2006@rediffmail.com . Website: www.bioinfobubpl.nic.in; www.ami2006.org

 

 

 

 

 

SFRR-India National Satellite Meeting

and

International Conference on Free Radicals In Clinical and Laboratory Medicine

4-5 January 2007, Cochin, India

 

Organized by the Department of Biochemistry, Amrita, Institute of Medical Sciences, the Society For Free Radical Research (SFRR; www.sfrr-india.org) satellite meeting and the conference will be held at Amrita Institute of Medical Sciences, Cochin, India on 4-5 January 2007. The topic to be covered will be Free Radicals on Health and Diseases with special reference to Clinical and Laboratory Medicine. Renowned scientists from India and abroad will share their experience. For further details please contact: The Organizing Secretary, Department of Biochemistry, Amrita Institute of Medical Sciences, Elamakkara P.O., Cochin 682026, India. E-mail: biochemistry@aims.amrita.edu

 

 

 

                                                    

Author Index

Ahmad Riyaz

699

Ahmed Q

745

Arockiasamy S

757

Arora Rajesh

699

Asif M

745

Austin Sr

719

Bagchi Divya

767

Bal Krishana

699

Bano Bilqees

745

Bhandarkar A G

740

Bose Bipasha

693

Chandra D

749

Deb Chitta Ranjan

762

Devasree L D

726

Ghosh S

749

Girhotra S

705

Goel A K

754

Gour Rekha R

693

Gupta S C

749

Ignacimuthu S

757

Jain Anuradha

767

Jayraw A K

749

Kaleem M

745

Kalorey D R

740

Kanth V Rajani

733

Kesavan M

719

Kirmani D

745

Kolte S W

740

Kumar C Sanat

733

Kumar Vijay

683

Kurkure N V

740

Kuttan Girija

719

Kuttan Ramadasan

719

Lakshmi V

754

Mandal R

705

Manpreet S

683

Mathur Deepti

699

Medhi B

683

Melchias G

757

Michael R Dinakaran

726

Motiwale Leena

693

Prakash O

683

Premsingh S

726

Raina O K

749

Rajagopalan K

719

Raju T N

733

Ram Raghubir

754

Ramana B Venkata

733

Rani S Sahaya

757

Rao K V K

693

Reddy G Bhanuprakash

733

Reddy P Uma Maheswara

733

Sagar Ravinder Kumar

699

Sharma Rakesh Kumar

699

Singh B P

749

Singh Shalini

699

Srirekha P

726

Srivastava M N

754

Sudhakaran D Samuel

726

Sumedh G

683

Suryanarayana P

733

Taneja S K

705

Temjensangba

762

Tharakan Sheeja T

719

Velusamy R

749

Verma Deepti

767

 

 

 

Keyword Index

Activated charcoal

762

AIDS

683

Aldose reductase

733

Antioxidant enzymes

733

Antioxidants

745

Bajra

757

Bioactivity

754

Bovine calves

749

Brain derived neurotropic  factor

699

Broilers

740

Catalytic property

767

Cataract

733

Curcumin

733

Cyanobacterium

767

Diabetes mellitus

745

Dyslipidemia

705

ELISA

749

Embryo cell

693

Fasciola gigantica

749

Fauna

754

Free radicals

745

Galactose

733

Herbal coxidiostat

740

Herbal drugs

719

HIV-1

683

HLA

683

Hypertension

705

Immature seed culture

762

Immunology

740

Immunostimulants

726

Immunosuppression

719

In vitro hardening

762

Increased S-phase

693

Leaf base

757

Malachite green

693

Malignant transformation

693

MAP kinases

693

Marine organism

754

Mass multiplication

762

Mature embryo

757

Metabolic syndrome-X

705

Metacercarial antigen

749

MHC

683

Neuroprotection

699

NIDDM

705

Nigella sativa

745

Obesity

705

Oreochromis mossambicus

726

Oxidative damage

733

Oxidative stress

745

Parkinson disease

699

Pearl millet

757

Plant growth regulators

762

Poaceae

757

Radiation damage

719

Rat

699

Regeneration

757

Regulatory property

767

Sulphur metabolizing enzyme

767

Synechococcus elongates

767

Syrian hamster embryo cells

693

Tilapia

726

Tinospora cordifolia

726

Traditional medicine

719

Vitamin-E

733

Zn- supplementation

705

 

 

 

Review Article

 

Indian Journal of Experimental Biology

Vol. 44, September 2006, pp. 683-692

 

 

 

Genetic basis of HIV-1 resistance and susceptibility: An approach to understand correlation between human genes and HIV-1 infection

Vijay Kumar, O Prakash, S Manpreet, G Sumedh & B Medhi

 

HIV infection is the serious medical and public health issue of present generation. By 2005, it has already infected a cumulative total of more than sixty million people worldwide and the number of HIV positive cases are rising day by day. India is currently estimated to have about 5.1 million infected persons with HIV-1 or AIDS (second only to South Africa) and this number could increase to 24 million in the next ten years. This pandemic situation of the AIDS stimulated a plethora of longitudinal cohort studies which are designed to document medical heterogeneity as well as to mitigate the factors that regulate the HIV-1 infection, disease progression and the immune defenses. In recent years these genetic studies have led to the discovery of various MHC and non MHC encoded genes, which directly or indirectly influence the susceptibility and resistance to HIV infection and AIDS.

These genes and their mutated forms and their products which play a major role in determining the susceptibility or resistance to HIV-1 infection and AIDS. These genes have been categorized into MHC or non MHC encoded genes. The MHC encoded genes which determine HIV resistance or susceptibility are HLA-B57, HLA-B58, HLA-B27, HLA-Bw4 and HLA-A11 in Southeast Asians. On the other hand, non MHC encoded genes are CCR5, CCR2, RANTES, CXCL12, CXCR6, CCL3L1, Interleukin-10 (IL-10), and interferon gamma. The site specific mutations in these genes determine the susceptibility or resistance to HIV-1 infection and AIDS. In future the study of host genes in relation to HIV-1 infection may provide the researchers to develop newer chemotherapeutic approaches to prevent or cure HIV-1 infection effectively.]

 

Papers

 

Indian Journal of Experimental Biology

Vol. 44, September 2006, pp.693-698

 

Differential role of MAP kinase isoforms in malachite green transformed Syrian hamster embryo fibroblasts in culture

Bipasha Bose, Rekha R Gour, Leena Motiwale & K V K Rao

 

Received 5 January 2006; revised 25 May 2006

Malachite green (MG) induces DNA damage and malignant transformation of Syrian hamster embryo (SHE) cells in primary culture. In the present study, we have studied the role of all the three isoforms of mitogen activated protein (MAP) kinases i.e. ERK (extracellular regulated kinase), JNK (JUN- N- terminal kinase) and p38 kinase during transformation of SHE cells by MG. The results showed that transformed cells were associated with a decreased expression of phosphoactive ERK and JNK and increased expression of p38 kinase as evident from the Western blot, immunofluorescence and flow cytometry studies. Also, a persistent nuclear localization of p38 kinase was observed in the transformed cells. The present study indicated that p38 kinase was present at higher levels and seemed to be associated with transformation, which suggested that inhibitors of p38 kinase could serve in general as potential agents for selective cancer therapy.

 

 

Indian Journal of Experimental Biology

Vol. 44, September 2006, pp.699-704

 

 

Neuroprotective effect of BDNF in young and aged 6-OHDA treated rat model of Parkinson disease

Shalini Singh, Riyaz Ahmad, Deepti Mathur, Ravinder Kumar Sagar & Bal Krishana*

 

and

Rajesh Arora & Rakesh Kumar Sharma

 

Received November 2005; revised 19 April 2006

Brain derived neurotrophic factor (BDNF) has been shown to exert trophic effects on dopaminergic neurons against 6-hydroxydopamine (6-OHDA) in young rat. Since the degeneration of substantia nigra dopaminergic neurons that occurs in Parkinson’s disease is more often than not confined to elderly individuals, it is of interest to determine whether the effects of BDNF against 6 hydroxydopamine (6-OHDA) in young rats can be extended to aged animals. 6-hydroxydopamine was stereotaxically injected into the striatum of young (3-months) and aged (24-months) rats, which were treated two hours earlier with BDNF. 6-OHDA results in almost complete destruction of substantia nigra pars compacta dopaminergic neurons. BDNF injection significantly changed apomorphine induced rotations from 132 ± 15 to 181 ± 10, staircase test from 73 ± 2% to 61 ± 3%, initiation time from 7 ± 2  to 12 ± 1 sec, and disengage time from 80 ± 7  to 90 ± 5 sec in young and aged animals, respectively. It is concluded that BDNF causes the limited behavior recovery of striatal DA systems from 6-OHDA toxicity in aged animals.

 

 

Indian Journal of Experimental Biology

Vol. 44, September 2006, pp.705-718

 

 

Long term excessive Zn–supplementation promotes metabolic syndrome-X in Wistar rats fed sucrose and fat rich semisynthetic diet

S K Taneja, R Mandal & S Girhotra

 

Received 31 August 2005; revised 2 June 2006

During the last two decades Zinc (Zn) as a micronutrient is being used indiscriminately in agricultural and husbandry practices and also in baby foods and multivitamin supplements with a view that Zn is non-toxic and promotes linear growth and body weight in the consumers. The long-term effect of increasing Zn load in the body has not been worked out so far. In this study, three groups of rats were fed on a semi-synthetic diet containing 20 mg (control, group-I), 40 mg (group-II) and 80 mg Zn /kg (group-III) diet respectively for 6 months. The results revealed that the gain in body weight increased in rats in Zn-concentration dependent manner. The urine examined on weekly basis showed glucosuria in group-II on week 10 and in group-III on week 8 and thereafter. The arterial blood pressure was significantly higher in group-II and III than their control counter parts on monthly basis. Histochemical examination of skin revealed an increase in the number of adipocytes filled with triglycerides making a subcutaneous fatty tissue thicker in group-II and group-III than that of control group. The blood profile after 180 days of dietary treatment, displayed a significant rise in glucose, total lipids, cholesterol, triglycerides, LDL-cholesterol, VLDL-cholesterol, insulin, cortisol and aldosterone whereas HDL-cholesterol, T3, T4 and TSH showed a reduction in their levels in the blood serum. The tissue metal status showed an increase of Zn, Cu and Mg in the serum, a rise in Zn in liver, hair and abdominal muscles and fall in Cu and Mg concentrations in liver, hair and abdominal muscles. This data suggest that Zn in excess in diet when fed for longer periods of time induces metabolic syndrome-X.

 

 

Indian Journal of Experimental Biology

Vol. 44, September 2006, pp.719-725

 

 

Effect of AC II, a herbal formulation on radiation-induced
immunosuppression in mice

Sheeja T Tharakan, Girija Kuttan & Ramadasan Kuttan

 

and

M Kesavan, Sr Austin & K Rajagopalan

 

Received 1 September 2005; revised 8 June 2006

A single dose of 6 Gy irradiation significantly reduced the total WBC count while in herbal formulation (AC II) treated groups it was found to be significantly increased. Similarly bone marrow cellularity and a-esterase positive cells, which were lowered by radiation, were partly restored in AC II treated groups. The data indicate that AC II can overcome the immunosuppression produced by irradiation.

 

 

Indian Journal of Experimental Biology

Vol. 44, September 2006, pp.726-732

 

 

Immunostimulatory effect of Tinospora cordifolia Miers leaf extract in
Oreochromis mossambicus

D Samuel Sudhakaran , P Srirekha , L D Devasree, S Premsingh  & R Dinakaran Michael

 

 

Received 17 March 2005; revised 5 May 2006

Immunostimulatory effect of leaf extract of T. cordifolia on (i) specific immunity (antibody response), (ii) non-specific immunity (neutrophil activity) and (iii) disease resistance against Aeromonas hydrophila was investigated in
O. mossambicus. Ethanol and petroleum ether extracts of the leaves were used. Both ethanol and petroleum ether extracts administered at doses of 0.8, 8 or 80 mg/kg body weight, prolonged the peak primary antibody titres upto one to three weeks. Ethanol extract at the dose of 8 mg/kg and petroleum ether extract at the doses of 0.8 or 8 mg/kg enhanced the secondary antibody response. All the doses of ethanol extract significantly enhanced neutrophil activity. Fish injected with petroleum ether or ethanol extract at a dose of 8 mg/kg were protected against experimental infection with virulent
A. hydrophila. The results indicates the potential of T. cordifolia leaf extracts for use as an immunoprophylactic to prevent diseases in finfish aquaculture.

 

 

Indian Journal of Experimental Biology

Vol. 44, September 2006, pp.733-739

 

 

Cumulative antioxidant defense against oxidative challenge in galactose-induced cataractogenesis in Wistar rats

T N Raju, C Sanat Kumar, V Rajani Kanth, B Venkata Ramana & P Uma Maheswara Reddy

 

and

P Suryanarayana & G Bhanuprakash Reddy

 

Received 23 December 2005; revised 1 May 2006

Natural dietary ingredients are known for their antioxidant activity. Of such, curcumin, the active principle of turmeric, at 0.01% in the diet proved as pro-oxidative in galactose-induced cataract in vivo. The purpose of this study was to investigate the effect of vitamin E (VE), a well-known antioxidant, in combination with curcumin on the onset and maturation of galactose induced cataract. Periodic slit-lamp microscope examination indicated that in combination with vitamin-E, 0.01% curcumin (G-IV) delayed the onset and maturation of galactose-induced cataract. Biochemical analyses revealed that combined treatment of 0.01% curcumin and vitamin-E diet exhibited an efficient antioxidant effect, as it inhibited lipid peroxidation and contributed to a distinct rise in reduced glutathione content. The results indicate that natural dietary ingredients are effective in combination rather than the individual administration as they are complementing each other in reducing the risk of galactose induced cataract.

 

 

Indian Journal of Experimental Biology

Vol. 44, September 2006, pp.740-744

 

 Evaluation of herbal coccidiostat ‘Coxynil’ in broiler

N V Kurkure, S W Kolte, A G Bhandarkar & D R Kalorey

 

Received 8 July 2005; revised 8 May 2006

Anticoccidial efficacy of "Coxynil" a polyherbal preparation was tested against Eimeria tenella in broilers. Body weight of birds challenged with E. tenella in Coxynil treated groups was higher as compared to Coxynil untreated. Oocyst out put, lesion score, HI titres against New Castle disease virus were significantly higher in Coxynil supplemented groups in comparison to Coxynil un-supplemented groups. Examination of ceaca of the birds, revealed that the Coxynil interfered with life cycle of coccidia. The typical second generation schizonts were absent in ceacal section of Coxynil treated groups. The results indicate that Coxynil is effective herbal coccidiostat.

 

 

Indian Journal of Experimental Biology

Vol. 44, September 2006, pp.745-748

 

 

Biochemical effects of Nigella sativa L seeds in diabetic rats

M Kaleem, D Kirmani, M Asif, Q Ahmed & Bilqees Bano*

 

Received 16 March 2005; revised 19 May 2006

Oral administration of ethanol extract of N. sativa seeds (300 mg/kg body weight/day) to streptozotocin induced diabetic rats for 30 days significantly reduced the elevated levels of blood glucose, lipids, plasma insulin and improved altered levels of lipid peroxidation products (TBARS and hydroperoxides) and antioxidant enzymes like catalase, superoxide dismutase, reduced glutathione and glutathione peroxidase in liver and kidney. The results confirm the antidiabetic activity of N. sativa seeds extract and suggest that because of its antioxidant effects its administration may be useful in controlling the diabetic complications in experimental diabetic rats.

 

 

Indian Journal of Experimental Biology

Vol. 44, September 2006, pp.749-753

 

 

Prepatent detection of Fasciola gigantica infection in bovine calves using metacercarial antigen

R Velusamy, B P Singh, S Ghosh, D Chandra, O K Raina, S C Gupta & A K Jayraw

 

Received 31 March 2006; revised 30 May 2006

Metacercarial antigen of Fasciola gigantica was evaluated for early immunodiagnosis of experimental bovine fasciolosis using ELISA and Western blot. In ELISA, the experimental F. gigantica infection was detected as early as 2 weeks post-infection (WPI). The gradual increasing trend of antibody level was observed from 2 to 7 WPI, followed by a plateau, which was maintained up to 14 WPI. In Western blot, sera from experimentally infected calves recognized one distinct polypeptide of 21 kDa in fractionated metacercarial antigen as early as 10 th day post infection. From 2 WPI, more polypeptide bands were reacting. Recognition of these protein bands persisted till the end of the experiment (14 WPI). Cattle sera collected from the field showed 34.5% seroprevalence of fasciolosis by ELISA using MAg. Comparative immunoblot studies of metacercarial antigen with anti-Gigantocotyle explanatum and anti-Paramphistomum epiclitum sera revealed that 21 and 25 kDa polypeptides of metacercarial antigen did not cross-react with any of these sera and appear to be unique to F. gigantica and having the desirable qualities of early and specific immunodiagnosis.

 

 

Indian Journal of Experimental Biology

Vol. 44, September 2006, pp.754-756

 

 

Bioactivity of marine organisms: Part X ľ Screening of some marine fauna from the Indian coasts

V Lakshmi, A K Goel , M N Srivastava  & Ram Raghubir

 

Received 25 November 2005

Methanolic and chloroform-methanol extracts of 25 identified species of marine fauna have been screened for a wide range of biological activities. Of these, 2 extracts exhibited diuretic activity, while antibacterial, antiviral, oxytocic and spasmolytic activities, were observed in 1 extract each.

 

 

Indian Journal of Experimental Biology

Vol. 44, September 2006, pp.757-761

 

 

Efficient protocols for in vitro regeneration of Pennisetum glaucum (L) Br.

S Arockiasamy, S Sahaya Rani, S Ignacimuthu & G Melchias

 

Received 2 November 2005; revised 10 March 2006

A system was developed for in vitro regeneration of Pennisetum glaucum through organogenesis and somatic embryogenesis. Mature embryo and leaf base explants of Pennisetum glaucum (L) Br. cv HH B60 (Poaceae) were cultured on Murashige and Skoog agar medium supplemented with 11.3 µM of 2,4-D for callus induction. Embryogenic calli were induced within eight weeks. Percentage of callus induction and somatic embryogenesis was significantly higher in mature embryo than leaf base explants. Maximum shoot regeneration was obtained via organogenesis on MS medium supplemented with 4.43 µM of BAP and 4.64 µM of kinetin from the calli of both the explants. The frequency of plant regeneration through somatic embryogenesis was comparatively lower than organogenesis. Regeneration frequency was higher in mature embryo explants than leaf base explants. The shoots regenerated via organogenesis were elongated and rooted efficiently on MS medium supplemented with IBA (0.49 µM). The rooted plantlets were hardened and transferred to soil.

 

 

 

Indian Journal of Experimental Biology

Vol. 44, September 2006, pp.762-766

 

 

In vitro propagation of threatened terrestrial orchid, Malaxis khasiana
Soland ex. Swartz through immature seed culture

Chitta Ranjan Deb & Temjensangba

 

Received 22 September 2005; revised 30 May 2006

Rapid in vitro propagation of the terrestrial orchid, M. khasiana through immature seed culture was achieved. Immature seeds of 8-9 week after pollination (WAP) cultured on MS medium (2% sucrose) supplemented with 500 mgl-1 casein-hydrolysate and 1 mM N6-benzyladenine (BA) exhibited germination of 75% seeds after 107 days of culture and subsequently supported the development of PLBs. Subsequent culture on MS medium enriched with 6 mM of indole-3-acetic acid (IAA), 18 mM each of BA and kinetin induced multiple shoots and plantlets. Transfer of PLBs to MS medium with 0.1% activated charcoal (AC) facilitated rapid proliferation of PLBs, while AC at 0.2% favored shoot bud induction and rhizome enlargement. The plantlets, developed on medium with IAA, BA and kinetin, after hardening in vitro for 8-10 weeks were planted in community pots and transferred to poly-house. The plantlets showed 65% survival under field conditions.

 

 

Indian Journal of Experimental Biology

Vol. 44, September 2006, pp.767-772

 

 

Catalytic and regulatory properties of sulphur metabolizing enzymes in cyanobacterium Synechococcus elongatus PCC 7942

Anuradha Jain, Deepti Verma & Divya Bagchi

 

Received 16 December 2005; revised 20 April 2006

Synechococcus elongatus PCC 7942 was able to grow with several S sources. The sulphur metabolizing enzymes viz. ATP sulphurylase, cysteine synthase, thiosulphate reductase and L- and D-cysteine desulphydrases were regulated by sulphur sources, particularly by sulphur amino acids and organic sulphate esters. Sulphur starvation reduced ATP sulphurylase and cysteine synthase whereas reduced glutathione appreciated Cys degradation activity. With partially purified enzymes apparent Km values for sulphate, ATP, D- and L-Cys, thiosulphate, sulphide and O-acetyl serine were in a range of 12-50 µM. p-Nitrophenyl sulphate inhibited ATP sulphurylase competitively. Met was a feedback inhibitor of several key enzymes.