Metabolic engineering of Escherichia coli W3110 strain by incorporating genome-level modifications and synthetic plasmid modules to enhance L-Dopa production from glycerol.

L-Tyrosine which is one of the terminal metabolites of highly regulated aromatic amino-acid biosynthesis pathway in Escherichia coli is a precursor for synthesis of L-Dopa. In this study, we report over production of L-Dopa by enhancing expression of rate limiting isoenzyme of shikimate kinase (aroL), chorismate synthase (aroC), aromatic-amino-acid aminotransferase (tyrB) and 3-phosphoshikimate 1-carboxyvinyltransferase (aroA) form a plasmid module harboring five enzymes under two inducible promoters converting shikimate to tyrosine. 4-hydroxyphenylacetate-3-hydrolase (hpaBC) which converts L-Tyrosine to L-Dopa was expressed constitutively from a separate plasmid module. Feedback deregulated expression of 3-Deoxy-D-arabinoheptulosonate-7-phosphate (DAHP) synthase (aroG*) replacing wild type aroG under its natural promoter led to enhancement of L-Dopa production. Deletion of transcriptional repressor tyrR and links to other competing pathways improved titers of L-Dopa. We focused on having a balanced flux by constitutive expression of pathway enzymes from plasmid constructs rather than achieving higher amounts of catalytic protein by induction. We observed glycerol when used as a carbon source for the final strain led to low acid production. The best performing strain led to decoupling of acid production and product formation in bioreactor. Fed batch analysis of the final strain led to 12.5 g/L of L-Dopa produced in bioreactor.

Synthesis of dopamine in E. coli using plasmid-based expression system and its marked effect on host growth profiles.

L-Dopa and dopamine are important pathway intermediates toward the synthesis of catecholamine such as epinephrine and norepinephrine from amino acid L-tyrosine. Dopamine, secreted from dopaminergic nerve cells, serves as an important neurotransmitter. We report the synthesis of dopamine by extending the aromatic amino acid pathway of Escherichia coli DH5α by the expression of 4-hydroxyphenylacetate-3-hydrolase (HpaBC) from E. coli and an engineered dopa decarboxylase (DDC) from pig kidney cell. The activity of HpaBC and DDC require 200 µM iron supplementation and 50 µM vitamin B6, respectively as additives to the growth media. The maximum concentration of L-dopa and dopamine obtained from the broth was around 26 and 27 mg/L after 24 hr of separate shake flask studies. We observed that in the presence of dopamine synthesized in vivo host growth was remarkably enhanced. These observations lead us to an interesting finding about the role of these catecholamines on bacterial growth. It is clear that synthesis of dopamine in vivo actually promotes growth much efficiently as compared to when dopamine is added to the system from outside. From HPLC and GC-MS data it was further observed that L-dopa was stable within the observable time of experiments whereas dopamine actually was subjected to degradation via oxidation and host consumption.

Influence of omega-3 fatty acids on Tamoxifen-induced suppression of rat mammary carcinogenesis.

We report here a detailed time course study of the individual and combined chemopreventive effects of Tamoxifen (Tam) and a high fish oil (FO) diet on multiple histologic parameters of mammary carcinogenesis. Groups of female Sprague-Dawley rats were injected ip with 1-methyl-1-nitrosourea at 50 days of age and assigned to either a control diet (20% corn oil [CO]) or a FO-rich diet (10% FO + 10% CO) in the presence and absence of Tam in the diet (0.6 ppm). Rats were sacrificed at weeks 4 (before palpable tumors), 8 and 12 (when ∼90% of control rats had palpable tumors). Our results demonstrate a major effect of Tam in inhibiting the development of early preneoplastic lesions. FO, while having a marginal protective effect of it own, enhanced the antitumor action of Tam on all histologic parameters of carcinogenesis, although the effects of the combination were not statistically different from those of Tam alone. The combination of FO and Tam was the only intervention that induced regression of established preneoplastic lesions. We also found that in contrast to plasma, only target tissue n-3 fatty acids (FAs) levels correlated with select tissue biomarkers of carcinogenesis whose expression was altered in a manner predictive of a protective effect. Our results demonstrating the potentially superior chemopreventive efficacy of Tam and n-3FA have important translational implications. Our data also emphasize the importance of local factors in affecting target tissue levels and biologic effects of n-3FA.

Case Report: Primary Squamous Cell Carcinoma of the Orbit in a Patient With Carney's Syndrome Treated With Multidisciplinary Approaches.

BACKGROUND: Squamous cell carcinoma (SCC) is a rare malignancy of invasive epithelium with keratinocyte differentiation, and it is the most common form of eyelid malignant neoplasm, comprising 5%-10% of malignancies. While SCC rarely affects the orbit, it may be involved through local invasion from a cutaneous primary site or extension by perineural invasion. Only 12 cases of primary orbital SCC have been reported until now. Here, we present a case of primary carcinoma of the right orbit with coexisting Carney's syndrome, a rare genetic disorder associated with multiple endocrine neoplasias (MEN) syndromes. CASE: A 62-year-old South Asian male presented with a painful swelling in the lateral aspect of the right eyebrow and protrusion of the eyeball in August 2020. He had a history of excision of Right atrial Myxoma in March 2020. Orbital computerized tomography (CT) and positron emission tomography (PET-CT) scans revealed an enhancing soft tissue lesion in the right orbit with the involvement of frontal and ethmoid sinuses. Biopsy confirmed HPV-related poorly differentiated SCC, positive for HPV-related markers. The patient received concurrent chemo irradiation with Cisplatin. Follow-up PET-CT done 3 months later showed a new lesion appeared in the right orbital region and right lobe of thyroid. Later had surgical excision and total thyroidectomy, and histopathological examination (HPE) from orbit was reported as invasive SCC and from the thyroid was reported as synchronous papillary thyroid cancer. The patient's proptosis resolved, and subsequent PET-CT and magnetic resonance imaging (MRI) scans did not show any residual or recurrent disease. CONCLUSION: Primary SCC of the orbit is an extremely rare disease, and this case report presents the 13th reported case and the first one associated with Carney's syndrome. As there is no standard treatment regimen for primary SCC of the orbit, this case highlights the use of multimodality treatment, including surgical excision and chemo irradiation. The findings emphasize the importance of early detection and management of this uncommon and life-threatening condition, providing hope for patients and aiding in the prevention of recurrence.

Discordance in Recommendation Between Next-Generation Sequencing Test Reports and Molecular Tumor Boards in India.

PURPOSE: Accurate understanding of the genomic and transcriptomic data provided by next-generation sequencing (NGS) is essential for the effective utilization of precision oncology. Molecular tumor boards (MTBs) aim to translate the complex data in NGS reports into effective clinical interventions. Often, MTB treatment recommendations differ from those in the NGS reports. In this study, we analyze the discordance between these recommendations and the rationales behind the discordances, in a non-high-income setting, with international input to evaluate the necessity of MTB in clinical practice. METHODS: We collated data from MTB that were virtually hosted in Chennai, India. We included patients with malignancies who had NGS reports on solid tissue or liquid biopsies, and excluded those with incomplete data. MTB forms and NGS reports of each clinical case were analyzed and evaluated for recommendation concordance. Concordance was defined as an agreement between the first recommendation in the MTB forms and the therapeutic recommendations suggested in the NGS report. Discordance was the absence of the said agreement. The rationales for discordance were identified and documented. RESULTS: Seventy MTB reports were analyzed with 49 cases meeting the inclusion criteria. The recommendation discordance was 49% (24 of 49). Discordant recommendations were mainly due to low level of evidence for the drug (75% of cases). CONCLUSION: The discordance between MTB and NGS vendor recommendations highlights the clinical utility of MTB. The educational experiences provided by this initiative are an example of how virtual academic collaborations can enhance patient care and provider education across geographic borders.

Dietary selenium supplementation modifies breast tumor growth and metastasis.

The survival rate for breast cancer drops dramatically once the disease progresses to the metastatic stage. Selenium (Se) is an essential micronutrient credited with having high anticancer and chemopreventive properties. In our study, we investigated if dietary Se supplementation modified breast cancer development in vivo. Three diets supplemented with sodium selenite, methylseleninic acid (MSA) or selenomethionine (SeMet), as well as a Se-deficient and a Se-adequate diet were fed to mice before mammary gland inoculation of 4T1.2 cells. The primary tumor growth, the numbers of cancer cells present in lungs, hearts, livers, kidneys and femurs and several proinflammatory cytokines were measured. We found that inorganic selenite supplementation provided only short-term delay of tumor growth, whereas the two organic SeMet and MSA supplements provided more potent growth inhibition. These diets also affected cancer metastasis differently. Mice fed selenite developed the most extensive metastasis and had an increased incidence of kidney and bone metastasis. On the other hand, mice fed the SeMet diet showed the least amount of cancer growth at metastatic sites. The MSA diet also provided some protection against breast cancer metastasis although the effects were less significant than those of SeMet. The cytokine profiles indicated that serum levels of interlukin-2, interleukin-6, interferon γ and vascular endothelial growth factor were elevated in SeMet-supplemented mice. There was no significant difference in tumor growth and the patterns of metastasis between the Se-deficient and Se-adequate groups. Our data suggest that organic Se supplementation may reduce/delay breast cancer metastasis, while selenite may exacerbate it.

Changes in proteomic profiles in different prostate lobes of male rats throughout growth and development and aging stages of the life span.

BACKGROUND: Aging-related changes in important cellular pathways in the prostate may promote a permissive environment for an increased risk for prostatic disease development such as prostate cancer. Our objectives were to examine for such changes, by systematically determining the effects of growth and development and aging on proteomic profiles in different lobes of the rat prostate. METHODS: Prostate lobes (dorsolateral lobe, DL and ventral lobe, VL) were obtained from male Fisher rats of various ages representing young (4 months), mature (12 months), old (18 months), and very old (24 months). Differentially expressed proteins between age groups in each lobe were identified using a proteomic approach, isobaric Tags for Relative and Absolute Quantitation (iTRAQ). Select changes in the DL and VL were verified by immunoblot analysis. RESULTS: iTRAQ identified 317 proteins with high confidence. iTRAQ discovered 12 and 6 proteins significantly modulated in response to growth and development in the DL and VL, respectively, and 42 and 29 proteins significantly modulated in response to aging in the DL and VL, respectively. Proteins modulated during growth and development in the DL and VL are involved in a variety of biological processes including cell communication and development, whereas proteins modulated during aging were predominantly related to antioxidant activity and immunity. Immunoblot analysis verified age-related changes for α-1 antitrypsin, annexin A1, hypoxia up-regulated protein 1, and 78 kDa glucose-regulated protein. CONCLUSIONS: Aging results in changes in numerous prostatic proteins and pathways which are mainly linked to inflammation and may lead to prostatic disease development.

Drug Development in Low- and Middle-Income Countries: Opportunity or Exploitation?

Low- and middle-income countries (LMICs) represent a diverse group of regions with varied cancer presentation. Drug development and accessibility across these regions have primarily been dependent on the trials initiated and conducted across high-income countries. Representation of LMIC regions in these trials in terms of study population has been minimal, leading to inequitable distribution of optimal and affordable cancer care. In spite of many challenges, LMICs have now increasingly been able to contribute to anticancer drug development. The opportunities present in LMICs must be explored and used in conjunction with due collaborative efforts from high-income countries, health care planners, and regulatory agencies. Global drug development trials should not only factor in suitable representation of LMICs but also design studies with pragmatic objectives and endpoints so that the trial results lead to equitable and affordable cancer care. Strengthening collaboration between cancer researchers from LMICs and high-income countries and empowering the local investigator with adequate resources will help remove current disparities.

Proteomic profiling of human plasma by iTRAQ reveals down-regulation of ITI-HC3 and VDBP by cigarette smoking.

Biomarkers in noninvasive fluids indicative of cigarette smoke's effects are urgently needed. In this pilot study, we utilized the proteomic approach, isobaric Tags for Relative and Absolute Quantitation (iTRAQ), to identify differentially expressed plasma proteins in healthy cigarette smokers compared to healthy nonsmokers; select proteins were further confirmed by immunoblot analysis. Significant, differentially expressed proteins identified in the plasma separated subjects based on their condition as smokers or nonsmokers. Several of the proteins identified in this study are associated with immunity and inflammatory responses and have been shown to be associated with tobacco-related diseases, including chronic obstructive pulmonary disease (COPD) and lung cancer. Proteins up-regulated in smokers included complement component 8 polypeptide chains α, ß, and γ, and mannose-binding protein C, and proteins down-regulated included inter-α-trypsin inhibitor heavy chain H3 (ITI-HC3) and vitamin D-binding protein (VDBP). In addition, gelsolin and vitronectin, known tissue leakage proteins, were up- and down-regulated, respectively. Our results demonstrate for the first time that chronic cigarette smoking can influence the expression profile of the human plasma proteome. Proteins identified in this pilot study may serve as candidate biomarkers of diseases resulting from exposure to cigarette smoke in future molecular epidemiological studies.

Modulations of benzo[a]pyrene-induced DNA adduct, cyclin D1 and PCNA in oral tissue by 1,4-phenylenebis(methylene)selenocyanate.

Tobacco smoking is an important cause of human oral squamous cell carcinoma (SCC). Tobacco smoke contains multiple carcinogens include polycyclic aromatic hydrocarbons typified by benzo[a]pyrene (B[a]P). Surgery is the conventional treatment approach for SCC, but it remains imperfect. However, chemoprevention is a plausible strategy and we had previously demonstrated that 1,4-phenylenebis(methylene)selenocyanate (p-XSC) significantly inhibited tongue tumors-induced by the synthetic 4-nitroquinoline-N-oxide (not present in tobacco smoke). In this study, we demonstrated that p-XSC is capable of inhibiting B[a]P-DNA adduct formation, cell proliferation, cyclin D1 expression in human oral cells in vitro. In addition, we showed that dietary p-XSC inhibits B[a]P-DNA adduct formation, cell proliferation and cyclin D1 protein expression in the mouse tongue in vivo. The results of this study are encouraging to further evaluate the chemopreventive efficacy of p-XSC initially against B[a]P-induced tongue tumors in mice and ultimately in the clinic.

Long-term survival in recurrent adrenocortical cancer.

Adrenocortical carcinoma (ACC) comprises approximately 0.02% of all malignant tumours, which are a very small fraction of a group of cancers that affect in 0.7 to 2 in 1 000 000 people per year. Recurrence is very common even after complete resection and prognosis is poor. We report a case of a sporadic form of ACC found in a 41-year-old Asian Bangladeshi man. His tumour was surgically excised completely with negative margins and he did not receive any adjuvant therapy. Four years later, adrenal adenoma was developed at his opposite side which was also excised. Then after a total duration of 7 years, he developed recurrence in both adrenal glands and extensive metastases to bilateral lungs, liver and abdominal wall. As per FIRM-ACT study, we started treatment with etoposide, doxorubicin, cisplatin plus mitotane (EDP-M), and the patient responded dramatically. He became symptom free and achieved radiological partial response just on completion of three cycles. To our knowledge, this is the first case of ACC in Bangladesh published in the literature. Managing rare cancers is always challenging due to the fact that clinicians lack practical experience in it. We believe that patient with a rare cancer with poor prognosis like ACC may also survive long, and extensive metastases can also be controlled.

The organoselenium compound 1,4-phenylenebis(methylene)selenocyanate inhibits 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone-induced tumorgenesis and enhances glutathione-related antioxidant levels in A/J mouse lung.

Selenium, in the form of 1,4-phenylenebis(methylene)selenocyanate (p-XSC) but not Se-enriched yeast (Se-yeast), was highly effective at inhibiting lung tumors induced by the tobacco specific nitrosamine (TSNA) 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) in A/J mice and at reducing NNK-induced DNA methylation and 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels in the lung. Our goal was to determine if p-XSC but not Se-yeast is effective at inducing levels of glutathione (GSH)-related antioxidants and reducing markers of GSH oxidation in the NNK-induced lung tumor model. In the first bioassay, 6-week-old mice were fed either control or experimental diets (containing 10 ppm as selenium from p-XSC or Se-yeast) and, beginning at 8 weeks of age, received NNK (3 micromol) by gavage once weekly for 8 weeks. After 18 weeks, p-XSC significantly reduced NNK-induced tumor burden by 74% (10.4 +/- 6.0 versus 2.7 +/- 1.5 tumors/mouse, P < 0.001) and tumor incidence from 96% to 68% (P < 0.01), whereas, Se-yeast had no effect. Lung GSH levels were unchanged by either NNK or Se-yeast, but were increased 70% in mice treated with both NNK and p-XSC (P < 0.01) and 41% in mice treated with p-XSC alone. In the second bioassay, the time course of effects of p-XSC was examined. As early as one week after initiation of p-XSC feeding lung and blood selenium levels were increased nearly six- and two-fold, respectively. Increases of 120% for GSH and 65% for Cys were observed in p-XSC groups compared to controls within one week after initiation of p-XSC feeding (P < 0.01). The levels of protein-bound:free GSH ratios and Cys ratios were significantly decreased in p-XSC-treated mice, regardless of NNK status, suggesting a decrease in the levels of oxidative stress. Altogether, these results indicate that p-XSC is a potent inducer of GSH and related thiol antioxidants in the lung leading to decreased levels of oxidative stress and suggest that p-XSC inhibits tumor formation, in part, by protecting against oxidative damage.

A novel biologically active acid stable liposomal formulation of docosahexaenoic acid in human breast cancer cell lines.

PURPOSE: The risk of breast cancer can be influenced by certain dietary components, such as the amount and type of dietary fatty acids ingested. Docosahexaenoic acid (DHA), a component of fish oil, is known to suppress rat mammary carcinogenesis, reduce cell growth and induce apoptosis in human breast cancer cell lines. The purpose of this study was to develop a novel nanoliposomal formulation that would encapsulate a concentrated amount of DHA and utilize lipids that could protect DHA from pH fluctuations and oxidation. METHODS: We developed an acid stable liposome formulation of DHA by utilizing ether and phytanyl lipids similar in structure to those found in Archaea, known to endure high acidity and temperature; we compared its biological activities with free DHA in human breast cancer cells. RESULTS: The mean size of the liposomal DHA was 137 ± 12 nm with a slightly negative charge; the encapsulation efficiency of DHA in the liposomes as determined by LC-MS/MS ranged from 60 to 80%; our formulation is resistant to oxidation and stable over a range of pH (1.0-7.4) at 37 °C for a duration of two hours. In MCF-7 cells, liposomal DHA (IC50 38.8 µM) significantly reduced cell viability more effectively than free DHA (IC50 72.5 µM, p = 0.0017). In MDA-MB-231 cells, liposomal DHA was also marginally more effective. Liposomal DHA was more effective than free DHA in inducing apoptosis in both cell lines. It altered proteins involved in cell growth, cell cycle, and apoptosis more effectively than free DHA in both cell lines; it up-regulated p21 and cleaved PARP, while P-AKT and P-S6 were down-regulated. CONCLUSIONS: We developed a novel biologically active acid stable liposomal DHA as a potentially useful formulation for breast cancer prevention.

Comparative excretion and tissue distribution of selenium in mice and rats following treatment with the chemopreventive agent 1,4-phenylenebis(methylene)selenocyanate.

In a previous preliminary investigation, we reported on the excretion, tissue disposition and metabolism of the chemopreventive agent 1,4-phenylenebis(methylene)selenocyanate (p-XSC) in the rat, but similar studies in the mouse have not been explored. Following the oral administration of p-XSC (50 micromol/kg body weight), selenium excretion in feces was comparable to that in urine in mice, but in rats, feces was the major route of excretion. Tetraselenocyclophane (TSC) was the major metabolite detected in mouse and rat feces. In both species, levels of selenium in exhaled air were negligible. At termination, in the mouse, the stomach had the highest selenium content followed by liver and blood, but lung and kidney contained negligible levels of selenium; in the rat, the selenium level in liver was the highest followed by kidney, stomach, blood and lung. The identification of TSC as a fecal metabolite in both species let us to postulate the following metabolic pathway: p-XSC-->glutathione conjugate (p-XSeSG)-->a selenol (p-XSeH)-->TSC. Since the glutathione conjugate appears to be the proximal precursor for the selenol metabolite that may be an important intermediate in cancer chemoprevention, we report for the first time the synthesis of p-XSeSG and its other potential metabolites, namely the cysteine- and N-acetylcysteine-conjugates of p-XSC. HPLC analysis of the urine and bile showed a few metabolites of p-XSC; none of which eluted with the synthetic standards described above. When we examined the conversion of p-XSC and p-XSeSG in vitro using rat cecal microflora, TSC was formed from p-XSeSG but not from p-XSC. The formation of TSC from p-XSC in vivo but not in vitro suggests that p-XSC needs to be metabolized to p-XSeSG or an intermediate derived from its further metabolism. Thus, p-XSeSG was given orally to rats and the results showed that the pattern of selenium excretion after p-XSeSG treatment was similar to that of p-XSC; TSC was also identified as a fecal metabolite of p-XSeSG. It may be that the conversion of p-XSeSG to TSC is too facile, or the mere conjugation of p-XSC with glutathione does not occur in rats and mice.

Sister Mary Jospeh's nodule as initial presentation of carcinoma caecum-case report and literature review.

Umbilical metastases [Sister Mary Joseph's nodules (SMJN)] are relatively rare and are associated usually with advanced intra-abdominal tumors from the gastrointestinal tract (GIT) or from the gynecological malignancies and they carry poor prognosis. Here we report a case of carcinoma caecum whose initial presentation was with umbilical metastases and a review of literature in relation to the umbilical metastases from colonic tumors.

Early Glottic Squamous Cell Carcinoma in a 16-Year-Old: Case Report, Review of the Literature and Pediatric Head and Neck Radiotherapy Guidelines.

Squamous cell carcinoma in children and adolescents is extremely rare. Less than 80 case reports have been reported in the literature since it was first reported in 1868. In this article, we intend to report a case where a 16-year-old girl who presented with complaints of change in voice was found to have early-stage vocal cord carcinoma on evaluation.

Genetic and environmental influences on plasma vitamin D binding protein concentrations.

Recent studies suggest that low vitamin D-binding protein (VDBP aka group-specific complement or Gc) concentrations may be linked with inflammatory-mediated conditions, including asthma, chronic obstructive pulmonary disease, and cancer. However, these studies may be confounded by substantial racial and ethnic or genetic differences. The purpose of this study was to test the hypothesis that circulating VDBP concentrations are significantly associated with genetic ancestry. We used a validated high-performance liquid chromatography tandem mass spectrometry assay of 25-hydroxyvitamin D3 and its downstream metabolite 24,25-dihydroxyvitamin D3. VDBP concentrations (milligrams per liter) were measured in duplicate using a commercial enzyme-linked immunosorbent assay among healthy African American (n = 56) and Caucasian American (n = 60) participants. Ancestry informative markers across the genome were used to estimate individual genetic ancestry proportions, designed to robustly distinguish between West African and European ancestry. Genotype-defined Gc isoforms were defined using rs7041 and rs4588 combination groups. VDBP concentration was correlated with both Gc isoform (r = 0.93, P < 0.001) and West African genetic ancestry (r = -0.66, P < 0.001). In the final model, Gc isoform, the catabolic ratio of serum vitamin D, oral contraceptive use, and body mass index remained significantly associated with VDBP concentration, after adjustment for genetic ancestry. Failure to adjust for Gc isoform may lead to spurious associations in studies of VDBP concentration and disease risk, particularly when the condition of interest may also be associated with genetic ancestry. The higher circulating VDBP concentrations and higher vitamin D catabolic rate among Caucasian Americans observed here appear to be consistent with lower bone mineral density and racial and ethnic differences in vitamin D-inducing cytokines.

Influence of DNA structures on the conversion of sanguinarine alkanolamine form to iminium form.

Sanguinarine exhibits pH dependent structural equilibrium between iminium form (structure I) and alkanolamine form (structure II) with a pKa of 7.4 as revealed from spectrophotometric titration. The titration data show that the compound exists almost exclusively as structure I and structure II in the pH range 1 to 6 and 8.5 to 11, respectively. The interaction of structure I and structure II to several B-form natural and synthetic double and single stranded DNAs has been studied by spectrophotometric, spectrofluorimetric and circular dichroic measurements in buffers of pH 5.2 and pH 10.4 where the physicochemical properties of DNA remain in B-form structure. The results show that structure I bind strongly to all B-form DNA structures showing typical hypochromism and bathochromism of the alkaloid's absorption maximum, quenching of steady-state fluorescence intensity and perturbations in circular dichroic spectrum. The structure II does not bind to DNA, but in presence of large amount of DNA significant population of structure I is generated, which binds to DNA and forms a structure I-DNA intercalated complex. The nature and magnitude of the spectral pattern are very much dependent on the structure as well as base composition of each DNA. The generation of the structure I from structure II is significantly affected by increasing ionic strength of the medium. The conversion of structure II to structure I in presence of high concentration of DNA in solution is explained through formation of a binding equilibrium process between structure II and structure I-DNA intercalated complex.