Investigating Bacopa monnieri L. Therapeutic Potential for the Treatment of Neurological Diseases

The popular perennial creeping plant known as Bacopa monnieri (also known as Brahmi) is being utilized in the Indian Ayurvedic medicine practice. It has a variety of bioactive phytoconstituents that have been used therapeutically to treat a number of serious illnesses. Ancient Vedic scholars used this herb because of its pharmacological effects, particularly as a nerve booster and nootropic supporter. However, it is vital to comprehend the active phytochemical components of Bacopa monnieri extract (BME) and their molecular mechanisms in order to better grasp the effect of BME on neurological illnesses and diseases. Understanding its active phytochemical constituents and their molecular processes is essential. Numerous clinical investigations indicated that BME may have neuroprotective benefits, so it is worthwhile to re-evaluate this wellknown plant. Here, we focused on neurological problems as we examined the pharmacological and phytochemical characteristics of BME. For their effective usage in neuroprotection and cognition, many clinical concerns and the synergistic potential of Bacopa extract have been investigated. Alzheimer's disease is a neurological condition caused by the production of reactive oxygen species, which also causes amyloid-beta (A) and tau protein aggregation and increases neuro-inflammation and neurotoxicity. Our review offers a more indepth molecular understanding of the neuroprotective functions of BME, which can also be connected to its therapeutic management of neurological illnesses and cognitive-improving effects.

Markers of Oxidative Stress and Tyrosinase Activity in Melasma Patients: A Biochemical Investigation

BACKGROUND

Melasma is a skin hyperpigmentary disorder that develops over time. Genetic factors, oxidative stress, female sex hormones, and UV light may all play a role in the disorder's progression.

AIMS

To compare the levels of oxidative stress and tyrosinase activity in melasma patients with healthy volunteers.

METHODS

After written consent, 130 patients were enrolled in a case-control study. 65 cases were of melasma disorder, and 65 were served as control. Homogenized skin tissues were taken and used to estimate superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH), glutathione peroxidase (GPx) (antioxidants), malondialdehyde (MDA) and tyrosine hydroxylase (TH).

RESULTS

Melasma patients had lower basal levels of systemic antioxidants than healthy subjects. Tyrosinase activity was shown to be greater in lesional skin than in non-lesional skin. In controls, there was a good positive relationship between TH and MDA and an excellent negative relationship between GPx and GSH. In melasma patients, there were significant associations between CAT, GPx, SOD and MDA.

CONCLUSIONS

Increased oxidative stress may affect tyrosinase activity and eumelanin synthesis via the anabolic pathway of melanin synthesis, according to our findings. In conclusion, we discovered a negative relationship between antioxidants and tyrosinase activity.

Red Seaweed-derived Compounds: A Desired Approach for Treating Cancer

Cancer is a collection of diseases in which aberrant cells grow uncontrolled and invade surrounding tissues. Cancer can be classified as carcinoma, sarcoma, leukemia, or lymphoma. The deadliest cancers are lung, breast, colorectal, pancreatic, and prostate. Chemotherapy, surgery, and radiotherapy are the usual cancer treatments. However, drug resistance poses a significant barrier to cancer treatment. Macroalgae are wellknown producers of bioactive compounds with antimicrobial, antioxidant, anti-inflammatory, and anti-cancer properties. Red algae, in particular, are a prominent source of bioactive substances, such as polysaccharides, phenolic compounds, lipids, sterols, alkaloids, and terpenoids. Therefore, molecules from marine resources could be an appealing way to identify new cancer treatment alternatives. This study aimed to provide a brief overview of what is currently known regarding the potential of red macroalgae in cancer treatment by discussing the primary therapeutic targets of the disease and identifying compounds or extracts with bioactive characteristics against them.

Lesional Temporal Lobe Epilepsy: Does the “Uncommon” Differ from the Common?

Objectives This study aims to evaluate the subgroup consisting of uncommon pathological entities presenting with temporal lobe epilepsy (TLE).

Methodology Twenty-four consecutively operated patients of lesional temporal lobe epilepsy were included in the study. Eleven cases were identified that had pathologies implicated as “uncommon” in previously done studies on the pathology of TLE. A subgroup analysis consisting of these uncommon lesions was done for clinical presentation and seizure outcome. The seizure outcome was assessed in terms of Engel and International League Against Epilepsy (ILAE) classification.

Results Nine different pathological entities were identified within the study group. The mean age at surgery was 18.6 years (range 2–30 years). The mean duration of epilepsy was 48.3 months and the average duration of follow-up was 39.2months. All patients had seizures as the only complaint except three. Three patients had focal-aware seizures, two had focal motor onset, and the rest all had focal-unaware seizures. Seven patients were seizure free and the average age at diagnosis for these patients was 15.4 years (range 2–24 years.). The duration of seizure in the postoperative seizure-free group was 29.7 months and it was 81 months for the other group. All the patients with persistent postoperative seizures had focal-unaware seizures preoperatively.

Conclusion Despite the small and heterogeneous nature of this subgroup of uncommon lesions causing temporal lobe epilepsy, the clinical presentation, prognostic factors, and seizure outcome are similar to the cohort of common pathologies, including mesial temporal sclerosis.

Correlation of Oxidative Stress with Melasma: An Overview

Melasma is a hypermelanotic skin disorder characterized by dark brown macules of symmetrical sizes and shapes that develop over time. Apart from the multiple etiological factors for melasma, such as hormonal imbalances, thyroid dysfunction, drugs, and contraceptive pills, a new and significant cause has been discovered: the effect of oxidative stress. Oxidative stress is the result of disequilibrium between reactive oxygen species and antioxidants in the cells. It is a key element that can cause skin hypopigmentation or hyperpigmentation. The physiological significance of reactive oxygen species and its function in skin health are addressed in this study. The development process and pathophysiology of reactive oxygen species with melasma disorder are also highlighted and the advantages of integrating antioxidants in clinical and experimental environments are discussed.

Liquid-based cytology versus conventional cytology in fine-needle aspirates of salivary gland neoplasms

Background

Liquid-based cytology (LBC) is a method of retrieving and processing of cytological material for the assessment of both gynecological and nongynecological cases introduced in 1996. Mostly conventional smears (CS) are prepared in Indian scenario; however, due to increasing popularity of LBC in nongynecology specimens, LBC is also used in few centers for diagnosing salivary gland neoplasm.

Aim

The aim of this study is to compare CS and LBC in fine-needle aspiration cytology (FNAC) of the salivary gland neoplasms in terms of cytomorphological details, adequacy, ease of interpretation, pitfalls, and diagnostic efficiency.

Materials and Methods

We conducted a prospective, observational, comparative study which included 64 salivary gland neoplasms. Both CS and LBC (SurePath) were prepared as per standard protocols and examined.

Results and Conclusion

In our study, specificity and positive predictive value of both the techniques (conventional and LBC) were found to be 100%. Sensitivity of both the techniques was found to be similar (66.7%). Negative predictive value and diagnostic accuracy of conventional technique were found to be almost similar to that of LBC technique (97.6% vs. 97.2% and 97.7% vs. 97.4%). In terms of adequacy and cellularity, CSs were better than LBC. Ease of interpretation was better with CSs due to abundant chondromyxoid stroma, an important clue in the diagnosis of pleomorphic adenoma. Nuclear details and background were better in LBC as compared to CS. Hence, we conclude that in salivary gland FNAC, both CS and LBC have similar diagnostic efficiency. however, interpretation of conventional smears is easier than Liquid Based Cytology especially in cases of pleomorphic adenoma. However, some advantages of LBC in respect to conventional cytology, with better-preserved morphology obtained from LBC becomes furthermore obligatory.

Tea in chemoprevention of cancer

This review summarizes available information on epidemiological and experimental data showing an association of tea consumption with cancer prevention. Studies showing cancer risk associated with tea consumption are also summarized. Tea is grown in about 30 countries and, next to water, is the most widely consumed beverage in the world. Experimental studies demonstrating the chemopreventive effects of tea have been conducted principally with green tea; limited studies have also assessed the usefulness of black tea. Majority of these studies have been carried out in skin tumor model system where consumption through drinking water of water extracts of tea or a polyphenolic fraction isolated from tea has been shown to afford protection against chemical carcinogen- or ultraviolet radiation-induced skin tumorigenesis. Tea consumption has also been shown to afford protection against chemical carcinogen-induced lung, forestomach, esophagus, duodenum, pancreas, liver, breast and colon carcinogenesis in specific bioassay models. Evidence has also accumulated showing that tea polyphenols prevent tumor promoter- and ultraviolet B-induced inflammatory responses in murine skin. The species and strains of animals, dose, route, frequency and duration of carcinogen administration, as well as types, route of administration and duration of tea or its polyphenolic component(s) treatment are described in detail. A brief description regarding mechanism(s) responsible for the broad chemopreventive effects of tea is provided. Epidemiologic studies, though inconclusive, in general suggest a possible preventive effect of tea consumption on human cancer. On the basis of available information, epidemiologic and experimental studies are ongoing to draw the possible relationship between tea consumption and cancer causation and prevention. Appropriate strategies for future clinical chemoprevention trials to translate animal data to human cancer risk are warranted.

Assessment of drain water receiving effluent from tanneries and its impact on soil and plants with particular emphasis on bioaccumulation of heavy metals

In the present study, impact of tannery and other industrial effluents on the physico-chemical characteristics of loamy drain water and their consequent impact on soil and plants irrigated with effluent have been studied. The study reveals most of the parameter pH, BOD5 and COD at sampling station I was higher than station II. Waste water quality at both Stations I and II exceeded prescribed limits (BIS) for safe disposal of effluents into the surface water Samples of soil and vegetables from the land irrigated with loamy drain water has been collected and analyzed for Cu, Zn, Ni, Cr Pb and Cd. The different metals showed different enrichment factor for loamy drain water irrigated soil and are as follows: Cd 30% (max), Pb 26%, Zn 18%, Cr 5%, Cu 5%, Ni 2% (min). For plant samples collected at polluted sites are Ni 46% spinach (whole plant) (max), Zn 42% spinach (whole plant), Cr 39% spinach (whole plant), Cu 33% spinach (whole plant), Pb 20% potato tuber, Cd 20% potato tuber (min). The levels of Zn 145, Cu 5.25, and Ni 39.25 microg/ g in spinach, Pb 29.25, Cr 38. 25 and Cd 3.2 microg/g in potato tuber grown on polluted soil irrigated with contaminated drain water were found more than the reference value, which may create chronic health hazard problem to human and cattle through food chain in long run. Accumulation of toxic heavy metals may be build up in the agriculturally productive land where it is treated with contaminated effluent enrich with metals in turn bio-concentrated in the edible fodder/plants.

Structural basis of the carbohydrate specificities of jacalin: an X-ray and modeling study

The structures of the complexes of tetrameric jacalin with Gal, Me-alpha-GalNAc, Me-alpha-T-antigen, GalNAcbeta1-3Gal-alpha-O-Me and Galalpha1-6Glc (mellibiose) show that the sugar-binding site of jacalin has three components: the primary site, secondary site A, and secondary site B. In these structures and in the two structures reported earlier, Gal or GalNAc occupy the primary site with the anomeric carbon pointing towards secondary site A. The alpha-substituents, when present, interact, primarily hydrophobically, with secondary site A which has variable geometry. O-H..., centered pi and C-H...pi hydrogen bonds involving this site also exist. On the other hand, beta-substitution leads to severe steric clashes. Therefore, in complexes involving beta-linked disaccharides, the reducing sugar binds at the primary site with the non-reducing end located at secondary site B. The interactions at secondary site B are primarily through water bridges. Thus, the nature of the linkage determines the mode of the association of the sugar with jacalin. The interactions observed in the crystal structures and modeling based on them provide a satisfactory qualitative explanation of the available thermodynamic data on jacalin-carbohydrate interactions. They also lead to fresh insights into the nature of the binding of glycoproteins by jacalin.

A simple 'paper smear' method for dry collection, transport and storage of cervical cytological specimens for rapid screening of HPV infection by PCR

Human papillomaviruses (HPVs) are major pathogens associated with the development of cancer of the uterine cervix, the most common malignant tumour of women worldwide. Reliable diagnosis of HPV infection, particularly the 'high-risk' types (16/18), may facilitate early identification of 'high-risk' populations for developing cervical cancer and may augment the sensitivity and specificity of primary cervical cancer screening programmes by complementing the conventional Pap test. A simple paper smear method has been developed for dry collection, transport and storage of cervical smears/scrapes at room temperature for subsequent detection of HPV DNA by PCR assay. Imprint biopsies, blood and fine-needle aspirates were also collected by this method. The cervical scrapes or other body fluids were smeared (within 0.5-1 cm diameter) and dried on to sterile small slides made of Whatman 3MM filter paper, and stored individually at room temperature or at 4 degrees C. A small piece (2-3 mm) of the paper smear was punched or cut out with a sterile surgical blade, boiled in an eppendorf tube containing 50 microl of distilled water for 5 min and used directly for PCR amplification. The quality and quantity of DNA derived from paper smears and the results of PCR amplifications for HPV type 16, BRCA1 and p53 genes were identical to those obtained from the same samples following collection in PBS, storage (-70 degrees C) and phenol-chloroform-based DNA extraction. DNA was stable in the paper smears for up to a year, whether stored at room temperature or at 4 degrees C. This method is simple, rapid and cost-effective, and can be effectively employed for large-scale population screening, especially for regions where the specimens are to be transported from distant places to the laboratory.

Human hair colonizing fungi in water sediments of India

Out of 144 samples of water sediments, 183 isolates belonging to 9 genera and 22 species were isolated. Fifty-nine isolates of Acremonium, 26 of Chrysosporium indicum, 22 of Chrysosporium keratinophilum, 17 of Malbranchea sp. and 10 of Microsporum gypseum were recovered. Acremonium implicatum, Chrysosporium georgii, Chrysosporium xerophilum and Geomyces pannorum were reported for the first time from India.

Studies on the function of yeast protein disulfide isomerase in renaturation of proteins

Renaturation of two enzymes lacking disulfide bonds, citrate synthase (CS), and glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and another protein containing disulfide bonds, lysozyme (LZM), were studied in order to dissect the possible chaperone function from the isomerase function of yeast protein disulfide isomerase (PDI). Our findings suggest no independent chaperone activity of yeast PDI with respect to the two enzymes lacking disulfide bonds, GAPDH and CS, since neither of these enzymes required PDI for renaturation. In contrast, a high level of renaturation of LZM was observed in the presence of PDI. Renaturation of LZM involved formation and rearrangement of disulfide bonds. Additional studies using LZM as a substrate were done to examine the role of cysteine residues in the two active sites of PDI. Studies with a series of cysteine to serine mutants and truncation mutants of yeast PDI revealed that the two active sites of PDI were not equal in activity. An intramolecular disulfide bond in at least one active site of PDI was required for the oxidation of reduced LZM. The first cysteine in each active site was necessary for disulfide bond rearrangement, i.e., isomerization, in LZM, while the second cysteine was not.

Cutaneous photoprotection from ultraviolet injury by green tea polyphenols

BACKGROUND

In animal models, extracts from green tea have been shown to be remarkably effective at reducing the severity of adverse human health effects of overexposure to ultraviolet (UV) radiation. Although sunscreens and other photoprotective measures have traditionally been used for this purpose, there is a need for additional measures and natural products are increasingly being explored for that purpose.

OBJECTIVE

Our purpose was to evaluate the effect of polyphenols from green tea on parameters associated with acute UV injury.

METHODS

Areas of skin of normal volunteers were treated with an extract of green tea or one of its constituents. Thirty minutes later, the treated sites were exposed to a 2 minimal erythema dose solar simulated radiation. UV-treated skin was examined clinically for UV-induced erythema, histologically for the presence of sunburn cells or Langerhans cell distributions, or biochemically for UV-induced DNA damage.

RESULTS

Application of green tea extracts resulted in a dose-dependent inhibition of the erythema response evoked by UV radiation. The (-)-epigallocatechin-3-gallate (EGCG) and (-)-epicatechin-3-gallate (ECG) polyphenolic fractions were most efficient at inhibiting erythema, whereas (-)-epigallocatechin (EGC) and (-)-epicatechin (EC) had little effect. On histologic examination, skin treated with green tea extracts reduced the number of sunburn cells and protected epidermal Langerhans cells from UV damage. Green tea extracts also reduced the DNA damage that formed after UV radiation.

CONCLUSION

Polyphenolic extracts of green tea are effective chemopreventive agents for many of the adverse effects of sunlight on human health and may thus serve as natural alternatives for photoprotection.

P53 tumor suppressor gene mutations in hepatocellular carcinoma patients in India

BACKGROUND

Specific mutations of the p53 tumor suppressor gene in hepatocellular carcinoma (HCC) have been reported from several parts of the world, but to the authors' knowledge to date the status of this gene has not been studied in HCC patients in India, where HCC is one of the major cancers and the frequency of chronic hepatitis B virus (HBV) as well as hepatitis C virus (HCV) infection and exposure to dietary aflatoxin B(1) is very high. The most frequent mutation of the p53 gene in HCC is an AGG(Arg) to AGT(Ser) missense mutation at codon 249 of exon 7.

METHODS

Liver biopsy specimens from 21 HCC patients and 10 healthy controls were obtained through surgery or by needle biopsy technique. Phenol-chloroform-extracted DNA specimens were employed for the detection of HBV infection and p53 gene mutations. Nucleotide mutations of exons 4-9 of the p53 gene were analyzed by polymerase chain reaction (PCR), single strand confirmation polymorphism, and direct sequencing. Third-generation sandwich enzyme-linked immunosorbent assay (ELISA) was used for the serologic detection of HBV and HCV infection.

RESULTS

Analysis of exons 4-9 of the p53 gene revealed only 3 mutations (3 of 21 specimens, 14.28%; 95% confidence interval, -0.7-29.3), 2 mutations at codon 249 showing G-->T transversions, and 1 mutation (4.7%) at codon 250 with a C-->T transition. The base substitutions at the third base of codon 249 resulted in a missense mutation leading to a change in amino acid from arginine to serine whereas at codon 250 it caused a change from proline to serine. Dot blot hybridization and PCR for HBV DNA from HCCs revealed 58.8% (10 of 17 specimens) and 90. 47% (19 of 21 specimens), positivity, respectively. ELISA for hepatitis B virus surface antigen in serum showed a positivity of 71. 42% (15 of 21 specimens), but there was only 40% positivity (8 of 20 specimens) for hepatitis B virus envelope antigen whereas 6 of 17 patients (35.29%) showed the presence of antibodies against hepatitis B virus envelope protein. No patient was found to be positive for the HCV antibody.

CONCLUSIONS

The very low frequency of p53 mutations and the extremely high frequency of HBV infection (> 90%) in HCC indicate that the mutations in the p53 gene frequently found in HCC reported from different endemic areas of the world may not play a direct role in the development of HCC in India. HBV infection and, possibly, exposure to the dietary aflatoxin B(1) appear to play major roles in the molecular pathogenesis of HCC in India.

P53 tumor suppressor gene mutations in hepatocellular carcinoma patients in India

BACKGROUND

Specific mutations of the p53 tumor suppressor gene in hepatocellular carcinoma (HCC) have been reported from several parts of the world, but to the authors' knowledge to date the status of this gene has not been studied in HCC patients in India, where HCC is one of the major cancers and the frequency of chronic hepatitis B virus (HBV) as well as hepatitis C virus (HCV) infection and exposure to dietary aflatoxin B(1) is very high. The most frequent mutation of the p53 gene in HCC is an AGG(Arg) to AGT(Ser) missense mutation at codon 249 of exon 7.

METHODS

Liver biopsy specimens from 21 HCC patients and 10 healthy controls were obtained through surgery or by needle biopsy technique. Phenol-chloroform-extracted DNA specimens were employed for the detection of HBV infection and p53 gene mutations. Nucleotide mutations of exons 4-9 of the p53 gene were analyzed by polymerase chain reaction (PCR), single strand confirmation polymorphism, and direct sequencing. Third-generation sandwich enzyme-linked immunosorbent assay (ELISA) was used for the serologic detection of HBV and HCV infection.

RESULTS

Analysis of exons 4-9 of the p53 gene revealed only 3 mutations (3 of 21 specimens, 14.28%; 95% confidence interval, -0.7-29.3), 2 mutations at codon 249 showing G-->T transversions, and 1 mutation (4.7%) at codon 250 with a C-->T transition. The base substitutions at the third base of codon 249 resulted in a missense mutation leading to a change in amino acid from arginine to serine whereas at codon 250 it caused a change from proline to serine. Dot blot hybridization and PCR for HBV DNA from HCCs revealed 58.8% (10 of 17 specimens) and 90. 47% (19 of 21 specimens), positivity, respectively. ELISA for hepatitis B virus surface antigen in serum showed a positivity of 71. 42% (15 of 21 specimens), but there was only 40% positivity (8 of 20 specimens) for hepatitis B virus envelope antigen whereas 6 of 17 patients (35.29%) showed the presence of antibodies against hepatitis B virus envelope protein. No patient was found to be positive for the HCV antibody.

CONCLUSIONS

The very low frequency of p53 mutations and the extremely high frequency of HBV infection (> 90%) in HCC indicate that the mutations in the p53 gene frequently found in HCC reported from different endemic areas of the world may not play a direct role in the development of HCC in India. HBV infection and, possibly, exposure to the dietary aflatoxin B(1) appear to play major roles in the molecular pathogenesis of HCC in India.

Thermodynamic analysis of chitooligosaccharide binding to Urtica dioica agglutinin by isothermal titration calorimetry

UDA (Urtica dioica agglutinin) contains two hevein like domains with two non-identical interacting sites and is specific for chitooligosaccharides. The binding of chitooligosaccharides to UDA was studied by Isothermal Titration Calorimetry. Each site is composed of three subsites, each binding to a sugar residue. Thermodynamic parameters obtained show that while chitobiose has two independent non-interacting sites, chitotriose, chitotetrose and chitopentose have two interacting sites on each monomer of UDA. Values of binding enthalpy (deltaH) increase almost by a factor of 7 in going from chitobiose to chitotriose indicating the existence of three subsites in the combining site of UDA. The binding constant for chitotetrose and chitopentose increase without any further enhancement in the values of deltaH indicating that for oligomers larger than chitotriose interaction is favoured entropically.

Hepatitis G virus (HGV) infection & its pathogenic significance in patients of cirrhosis

In the present study the hepatitis G virus (HGV) infection and its pathogenic significance in patients of cirrhosis were assessed using reverse transcription plus nested polymerase chain reaction (RT-PCR). Serum samples were collected from a total of 50 patients of histologically proven non-alcoholic cirrhosis and from a control group consisting of 50 healthy voluntary blood donors. HGV RNA was detected by RT-PCR using primer sequences located in the conserved NS3 helicase region of HGV genome. Serological evaluation for markers of chronic infection with HBV (HBsAg, IgG anti-HBc, HBeAg) and HCV (anti-HCV) was carried out using commercially available kits. HBV DNA and HCV RNA were also tested by PCR in those samples that were found to be non-B, non-C by serological assays. Serological evidence of exposure to HBV was found in 31 (62%) and to HCV in 15 (30%) patients. HGV RNA was detected in 6 (12%) cirrhosis patients and in 2 (4%) healthy blood donors but the difference between the two groups was not statistically significant. Of the 6 HGV positive patients, 2 were coinfected with HBV, 1 with HCV, while the remaining 3 belonged to non-B, non-C category. No significant difference was observed in the clinical and biochemical profiles of HGV-positive and HGV-negative patients except that a history of blood transfusion was significantly (P < 0.005) more common in the former. The findings indicate that the HGV infection is commonly observed in both cirrhosis patients as well as healthy blood donors. A significant association of the virus with blood transfusion is indicative of a parenteral route of transmission. The observations of this study also suggest that the pathogenic role of HGV in the causation of liver disease may be insignificant.

Identification of cysteine and lysine residues present at the active site of beef liver glutamate dehydrogenase by o-phthalaldehyde

Beef liver glutamate dehydrogenase (GDH) is inactivated by the bifunctional reagent, o-phthalaldehyde. The initial rate of inactivation follows pseudo first-order kinetics. The reaction of the enzyme with o-phthalaldehyde results in isoindole derivative formation which is characterized by typical fluorescence emission and excitation maximum at 410 nm and 337 nm, respectively. The inactivation of GDH by o-phthalaldehyde is partially prevented by alpha-ketoglutaric acid, whereas NADH does not provide any protection. This clearly indicates that cysteine and lysine residues are located near the alpha-ketoglutaric acid binding center. The dissociation constant of 2.2 mM was obtained for enzyme-alpha-ketoglutaric acid complex. Stoichiometry of o-phthalaldehyde binding with glutamate dehydrogenase showed that the formation of approximately one isoindole derivative per subunit of glutamate dehydrogenase is accompanied by complete loss of activity.

Genetic transformation of glutamine auxotrophy to prototrophy in the cyanobacterium Nostoc muscorum

Glutamine auxotrophic (Gln-) and L-methionine D,L-sulfoximine (MSX) resistant (MSXr) mutants of N. muscorum were isolated and characterized for nitrogen nutrition, nitrogenase activity, glutamine synthetase (GS) activity and glutamine amide, alpha-keto-glutarate amido transferase (GOGAT) activity. The glutamine auxotroph was found to the GOGAT-containing GS-defective, incapable of growth with N2 or NH4+ but capable of growth with glutamine as nitrogen source, thus, suggesting GS to be the primary enzyme of both ammonia assimilation and glutamine formation in the cyanobacterium. The results of transformation and reversion studies suggests that glutamine auxotrophy is the result of a mutation in the gln A gene and that gln A gene can be transferred from one strain to another by transformation.