Showing papers by "Rakesh K. Jain published in 2007"

Angiogenesis in brain tumours

Abstract: Despite aggressive surgery, radiotherapy and chemotherapy, malignant gliomas remain uniformly fatal. To progress, these tumours stimulate the formation of new blood vessels through processes driven primarily by vascular endothelial growth factor (VEGF). However, the resulting vessels are structurally and functionally abnormal, and contribute to a hostile microenvironment (low oxygen tension and high interstitial fluid pressure) that selects for a more malignant phenotype with increased morbidity and mortality. Emerging preclinical and clinical data indicate that anti-VEGF therapies are potentially effective in glioblastoma — the most frequent primary brain tumour — and can transiently normalize tumour vessels. This creates a window of opportunity for optimally combining chemotherapeutics and radiation.

Effect of vascular normalization by antiangiogenic therapy on interstitial hypertension, peritumor edema, and lymphatic metastasis: insights from a mathematical model.

Abstract: Preclinical and clinical evidence shows that antiangiogenic agents can decrease tumor vessel permeability and interstitial fluid pressure (IFP) in a process of vessel "normalization." The resulting normalized vasculature has more efficient perfusion, but little is known about how tumor IFP and interstitial fluid velocity (IFV) are affected by changes in transport properties of the vessels and interstitium that are associated with antiangiogenic therapy. By using a mathematical model to simulate IFP and IFV profiles in tumors, we show here that antiangiogenic therapy can decrease IFP by decreasing the tumor size, vascular hydraulic permeability, and/or the surface area per unit tissue volume of tumor vessels. Within a certain window of antiangiogenic effects, interstitial convection within the tumor can increase dramatically, whereas fluid convection out of the tumor margin decreases. This would result in increased drug convection within the tumor and decreased convection of drugs, growth factors, or metastatic cancer cells from the tumor margin into the peritumor fluid or tissue. Decreased convection of growth factors, such as vascular endothelial growth factor-C (VEGF-C), would limit peritumor hyperplasia, and decreased VEGF-A would limit angiogenesis in sentinel lymph nodes. Both of these effects would reduce the probability of lymphatic metastasis. Finally, decreased fluid convection into the peritumor tissue would decrease peritumor edema associated with brain tumors and ascites accumulation in the peritoneal or pleural cavity, a major complication with a number of malignancies.

Tumor microenvironment abnormalities: causes, consequences, and strategies to normalize.

Abstract: A solid tumor is an organ-like entity comprised of neoplastic cells and non-transformed host stromal cells embedded in an extracellular matrix. The expression of various genes is influenced by interactions among these cells, surrounding matrix, and their local physical and biochemical microenvironment. The products encoded by these genes, in turn, control the pathophysiological characteristics of the tumor, and give rise to the abnormal organization, structure, and function of tumor blood vessels. These abnormalities contribute to heterogeneous blood flow, vascular permeability, and microenvironment. Proliferating tumor cells produce solid stress which compresses blood and lymphatic vessels. As a result of vessel leakiness and lack of functional lymphatics, interstitial fluid pressure is significantly elevated in solid tumors. Each of these abnormalities forms a physiological barrier to the delivery of therapeutic agents to tumors. Furthermore, the metabolic microenvironment in tumors such as hypoxia and acidosis hinder the efficacy of anti-tumor treatments such as radiation therapy and chemotherapy. A judicious application of anti-angiogenic therapy has the potential to overcome these problems by normalizing the tumor vessels and making them more efficient for delivery of oxygen and drugs. Combined anti-angiogenic and conventional therapies have shown promise in the clinic.

Endothelial cells derived from human embryonic stem cells form durable blood vessels in vivo.

Abstract: We describe the differentiation of human embryonic stem (hES) cells into endothelial cells using a scalable two-dimensional method that avoids an embryoid-body intermediate. After transplantation into severe combined immunodeficient (SCID) mice, the differentiated cells contributed to arborized blood vessels that integrated into the host circulatory system and served as blood conduits for 150 d.

A protocol for phenotypic detection and enumeration of circulating endothelial cells and circulating progenitor cells in human blood

Abstract: Blood circulating endothelial cells (CECs) and circulating hematopoietic progenitor cells (CPCs) represent two cell populations that are thought to play important roles in tissue vascularization. CECs and CPCs are currently studied as surrogate markers in patients for more than a dozen pathologies, including heart disease and cancer. However, data interpretation has often been difficult because of multiple definitions, methods and protocols used to evaluate and count these cells by different laboratories. Here, we propose a cytometry protocol for phenotypic identification and enumeration of CECs and CPCs in human blood using four surface markers: CD31, CD34, CD133 and CD45. This method allows further phenotypic analyses to explore the biology of these cells. In addition, it offers a platform for longitudinal studies of these cells in patients with different pathologies. The protocol is relatively simple, inexpensive and can be adapted for multiple flow cytometer types or software. The procedure should take 2–2.5 h, and is expected to detect 0.1–6.0% viable CECs and 0.01–0.20% CPCs within blood mononuclear cell population.

Active versus passive mechanisms in metastasis: do cancer cells crawl into vessels, or are they pushed?

Abstract: Although millions of cells are shed from a tumour every day, haematogenous metastasis is believed to be very inefficient. This inefficiency is widely assumed to be a result of the destruction of cells in the bloodstream by shear stress and the immune system and a slow rate of extravasation and proliferation in the stroma at a secondary site. Here, we propose that, whereas active intravasation of cells into the circulation is important in some tumours, others might shed cells passively into the blood or lymphatic vessels without the involvement of active cell migration. We discuss the evidence for and against this passive-shedding hypothesis and the implications for future treatments.

Robust 3-D Modeling of Vasculature Imagery Using Superellipsoids

Abstract: This paper presents methods to model complex vasculature in three-dimensional (3-D) images using cylindroidal superellipsoids, along with robust estimation and detection algorithms for automated image analysis. This model offers an explicit, low-order parameterization, enabling joint estimation of boundary, centerlines, and local pose. It provides a geometric framework for directed vessel traversal, and extraction of topological information like branch point locations and connectivity. M-estimators provide robust region-based statistics that are used to drive the superellipsoid toward a vessel boundary. A robust likelihood ratio test is used to differentiate between noise, artifacts, and other complex unmodeled structures, thereby verifying the model estimate. The proposed methodology behaves well across scale-space, shows a high degree of insensitivity to adjacent structures and implicitly handles branching. When evaluated on synthetic imagery mimicking specific structural complexities in tumor microvasculature, it consistently produces ubvoxel accuracy estimates of centerlines and widths in the presence of closely-adjacent vessels, branch points, and noise. An edit-based validation demonstrated a precision level of 96.6% at a recall level of 95.4%. Overall, it is robust enough for large-scale application

Matrix Metalloproteinases-1 and -8 Improve the Distribution and Efficacy of an Oncolytic Virus

Abstract: Oncolytic viral vectors show enormous potential for the treatment of many solid tumors. However, these vectors often suffer from insufficient delivery within tumors, which limits their efficacy in both preclinical and clinical settings. We have previously shown that tumor collagen can significantly hinder diffusion, and that its degradation can enhance the distribution and efficacy of an oncolytic herpes simplex virus (HSV) vector. Here, we identify two members of the matrix metalloproteinase (MMP) family of enzymes, MMP-1 and MMP-8, which can modulate the tumor matrix and enhance HSV delivery and efficacy. We show that overexpression of MMP-1 and MMP-8 in the human soft tissue sarcoma HSTS26T leads to a significant depletion of tumor-sulfated glycosaminoglycans. This increases the hydraulic conductivity of these tumors and enhances the flow of virus during injection. In control tumors, injected virus accumulates primarily in the periphery of the tumor. In contrast, we observed a more widespread distribution of virus around the injection site in MMP-1- and MMP-8-expressing tumors. Due to this enhanced vector delivery, MMP-expressing tumors respond significantly better to oncolytic HSV treatment than control tumors. Thus, these findings introduce a new approach to improve the delivery and efficacy of oncolytic viral vectors: modulation of tumor glycosaminoglycans to enhance convection.

Antiangiogenics: The Potential Role of Integrating This Novel Treatment Modality With Chemoradiation for Solid Cancers

Abstract: Although still in very early stages of clinical development, the combination of antiangiogenics with contemporary chemoradiotherapy regimens has emerged as a feasible and promising approach to many cancers. We review the rationale and the current understanding of antiangiogenics and their therapeutic potential in combination with chemoradiotherapy. Finally, we offer a perspective on future research directions aimed at making this complex therapeutic approach successful in the clinic.

Role of Perfusion CT in Glioma Grading and Comparison with Conventional MR Imaging Features

Abstract: BACKGROUND AND PURPOSE: Perfusion imaging using CT can provide additional information about tumor vascularity and angiogenesis for characterizing gliomas. The purpose of our study was to demonstrate the usefulness of various perfusion CT (PCT) parameters in assessing the grade of treatment-naive gliomas and also to compare it with conventional MR imaging features. MATERIALS AND METHODS: PCT was performed in 19 patients with glioma (14 high-grade gliomas and 5 low-grade gliomas). Normalized ratios of the PCT parameters (normalized cerebral blood volume [nCBV], normalized cerebral blood flow [nCBF], normalized mean transit time [nMTT]) were used for final analysis. Conventional MR imaging features of these tumors were assessed separately and compared with PCT parameters. Low- and high-grade gliomas were compared by using the nonparametric Wilcoxon 2-sample tests. RESULTS: Mean nCBV in the high- and low-grade gliomas was 3.06 ± 1.35 and 1.44 ± 0.42, respectively, with a statistically significant difference between the 2 groups (P = .005). Mean nCBF for the high- and low-grade gliomas was 3.03 ± 2.16 and 1.16 ± 0.36, respectively, with a statistically significant difference between the 2 groups (P = .045). Cut points of >1.92 for nCBV (85.7% sensitivity and 100% specificity), >1.48 for nCBF (71.4% sensitivity and 100% specificity), and 1.92 or nCBF of >1.48 improved the sensitivity and specificity to 92.9% and 100%, respectively. The sensitivity and specificity for diagnosing a high-grade glioma with conventional MR imaging were 85.7% and 60%, respectively. CONCLUSIONS: PCT can be used for preoperative grading of gliomas and can provide valuable complementary information about tumor hemodynamics, not available with conventional imaging techniques. nCBV was the single best parameter correlating with glioma grades, though using nCBF when nCBV was 1.92 was found to identify the high-grade gliomas.

Antiangiogenic therapy for normalization of atherosclerotic plaque vasculature: a potential strategy for plaque stabilization.

Abstract: Angiogenesis within human atherosclerotic plaques has an important role in plaque progression as immature blood vessels leak red blood cells and inflammatory mediators into the plaque center. Accumulation of free cholesterol from red blood cell membranes potentially increases the size of the necrotic core and triggers a chain of events that promote plaque destabilization. Antiangiogenic agents have been shown to prune some tumor vessels and 'normalize' the structure and function of the remaining vasculature, thereby improving the access of chemotherapeutic agents to tumors. We propose that antiangiogenic therapy can similarly stabilize vulnerable 'rupture-prone' plaques by pruning and normalizing immature intraplaque vessels, preventing further intraplaque hemorrhage. This normalization would limit necrotic core enlargement, further luminal narrowing and the degree of inflammation. Such normalization has been realized using vascular endothelial growth factor antagonists for the treatment of cancer and age-related macular degeneration. The development of this novel approach to prevent plaque progression might add to the armamentarium of preventive measures for acute myocardial infarction, stroke and sudden cardiac death.

Complete pathological response to bevacizumab and chemoradiation in advanced rectal cancer

Abstract: Localized rectal adenocarcinoma responds well to 5-fluorouracil/radiation-based therapy. Willett et al. present the case of a 55-year-old woman who was diagnosed with extensive and locally invasive carcinoma of the rectum and received bevacizumab in combination with chemoradiotherapy. Upon completion of neoadjuvant therapy, the patient underwent abdominoperineal resection with posterior vaginectomy, hysterectomy and bilateral salpingo-oophorectomy. The authors discuss the complete response seen in this patient and insights into the application and clinical management of using anti-VEGF therapy with chemoradiation. Background Localized rectal cancer responds well to 5-fluorouracil and radiation-based regimens. A phase I–II trial is currently testing the efficacy of adding bevacizumab, a VEGF-specific antibody, to standard chemoradiotherapy. The case presented here is a complete pathological response seen in a patient with extensive and locally invasive carcinoma after receiving this combined treatment. Investigations Physical examination, rectal ultrasound, PET–CT scan, laboratory tests, proctoscopic examination, chest radiograph, rectal forcep biopsies with immunohistochemistry, and protein and flow cytometric analyses. Diagnosis Large, invasive, ultrasound stage T4 carcinoma of the rectum, which was positive for survivin. Management One 2-week cycle of bevacizumab alone, followed by 3 cycles of bevacizumab with continuous 5-fluorouracil infusion, and external-beam radiation therapy given 5 days per week to the pelvis, abdominoperineal resection with posterior vaginectomy, hysterectomy and bilateral salpingo-oophorectomy.

A phase II study of sunitinib in patients with advanced hepatocellular carcinoma

Abstract: 4637 Background: Patients (pts) with advanced hepatocellular carcinoma (HCC) have a poor prognosis. HCC is a highly vascular tumor with increased levels of angiogenic factors including VEGF and VEG...

Bacillus lehensis sp. nov., an alkalitolerant bacterium isolated from soil.

Abstract: A Gram-positive, endospore-forming, alkalitolerant bacterial strain, designated MLB2T, was isolated from soil from Leh, India, and was subjected to a polyphasic taxonomic study. The strain exhibited phenotypic properties that included chemotaxonomic characteristics consistent with its classification in the genus Bacillus. Growth was observed at pH 7.0-11.0, but not at pH 6.0. The DNA G+C content was 41.4 mol%. The highest level of 16S rRNA gene sequence similarity was with Bacillus oshimensis JCM 12663T (98.8 %). However, DNA-DNA hybridization experiments indicated low levels of genomic relatedness with the type strains of B. oshimensis (62 %), Bacillus patagoniensis (55 %), Bacillus clausii (51 %) and Bacillus gibsonii (34 %), the species with which strain MLB2T formed a coherent cluster (based on the results of the phylogenetic analysis). On the basis of the phenotypic characteristics and genotypic distinctiveness of strain MLB2T, it should be classified within a novel species of Bacillus, for which the name Bacillus lehensis sp. nov. is proposed. The type strain is MLB2T (=MTCC 7633T=JCM 13820T).

Non-Uniform Plasma Leakage Affects Local Hematocrit and Blood Flow: Implications for Inflammation and Tumor Perfusion

Abstract: Vessel leakiness is a hallmark of inflammation and cancer. In inflammation, plasma extravasation and leukocyte adhesion occur in a coordinated manner to enable the immune response, but also to maintain tissue perfusion. In tumors, similar mechanisms operate, but they are not well regulated. Therefore, blood perfusion in tumors is non-uniform, and delivery of blood-borne therapeutics is difficult. In order to analyze the interplay among plasma leakage, blood viscosity, and vessel geometry, we developed a mathematical model that explicitly includes blood cells, vessel branching, and focal leakage. The results show that local hemoconcentration due to plasma leakage can greatly increase the flow resistance in individual vascular segments, diverting flow to other regions. Similarly, leukocyte rolling can increase flow resistance by partially blocking flow. Vessel dilation can counter these effects, and likely occurs in inflammation to maintain blood flow. These results suggest that potential strategies for improving perfusion through tumor networks include (i) eliminating non-uniform plasma leakage, (ii) inhibiting leukocyte interactions, and (iii) preventing RBC aggregation in sluggish vessels. Normalization of tumor vessels by anti-angiogenic therapy may improve tumor perfusion via the first two mechanisms.

Down-regulation of placenta growth factor by promoter hypermethylation in human lung and colon carcinoma.

Abstract: Two recent clinical trials have shown that the placenta growth factor (PlGF) is up-regulated after bevacizumab treatment in colorectal cancer and after SU11248 treatment in metastatic renal cell carcinoma. The regulation of expression for the vascular endothelial growth factor (VEGF) has been well documented in human tumors; however, the data for PlGF are lacking. We investigated the epigenetic regulation of PlGF and correlated the results with clinicopathologic features. We used plgf promoter analysis, cDNA microarray, immunohistochemistry, and Northern blot analysis to determine the expression level of PlGF in 22 human lung carcinoma and 11 colorectal tumors and in 12 cell lines. Sodium bisulfite modification of genomic DNA followed by methylation-specific PCR (MSP) and sequencing were used to determine the methylation status of the PlGF promoter. Treatments with 5-aza-2'-deoxycytidine and trichostatin A (TSA) were used to reactivate PlGF expression. Significance analysis showed that PlGF expression level was low in human lung and colorectal tumor tissues and in cell lines. PlGF gene promoter was hypermethylated. Treatment with the demethylating agent 5-Aza-dC restored PlGF transcript expression in the lung and colon carcinoma cell lines. By combining the results from cDNA microarray, immunohistochemistry, and MSP, we report, for the first time, that the PlGF gene promoter is methylated, and methylation may be one of the mechanisms that contributes to the low PlGF expression level in human lung and colorectal tumor tissues and cell lines.

Targeted Therapy in Rectal Cancer

Abstract: Epidermal growth factor receptor (EGFR) and vascular endothelial growth factor (VEGF) are often overexpressed in colorectal cancer and are associated with inferior outcomes. Based on successful randomized phase III trials, anti-EGFR and anti-VEGF therapeutics have entered clinical practice. Cetuximab (Erbitux), an EGFR-specific antibody, is currently approved in the United States in combination with irinotecan (Camptosar) for patients with metastatic colorectal cancer refractory to irinotecan or as a single agent for patients unable to tolerate irinotecan-based therapy. In retrospective analyses, patients with EGFR-expressing rectal cancer undergoing neoadjuvant radiation therapy had a significantly inferior disease-free survival and lower rates of achieving pathologic complete response. Based on the positive data in metastatic colorectal cancer and synergy with radiation therapy seen in preclinical models, there is a strong rationale to combine cetuximab with neoadjuvant radiation therapy and chemotherapy in rectal cancer. Bevacizumab (Avastin), a VEGF-specific antibody, was the first antiangiogenic agent to be approved in the United States for use in combination with standard chemotherapy in the first- and second-line of treatment in metastatic colorectal cancer. VEGF-targeted therapy may lead to indirect killing of cancer cells by damaging tumor blood vessels, and may increase the radiosensitivity of tumor-associated endothelial cells. VEGF blockade can also "normalize" tumor vasculature, thereby leading to greater tumor oxygenation and drug penetration. This review will address completed and ongoing trials that have established and continue to clarify the effects of these agents in rectal cancer.

Ultrasound biomicroscopic quantification of the change in anterior chamber angle following laser peripheral iridotomy in early chronic primary angle closure glaucoma.

Abstract: To prospectively evaluate by ultrasound biomicroscopy (UBM) and gonioscopy the anterior chamber angle widening following laser peripheral iridotomy (LPI) in eyes with early chronic primary angle closure glaucoma (CACG). A total of 55 eyes of 55 patients with CACG presenting with less than 180° peripheral anterior synechiae (PAS) were enrolled in the study. Angles were assessed by gonioscopy (Shaffer's grading) and UBM, before and 4 weeks after LPI. The angle opening distance at 250 and 500 μm from the scleral spur (AOD 250 and AOD 500) was computed. Results were analysed using the Wilcoxon signed-rank test. In the quadrant with LPI, the mean gonioscopy grade increased significantly from 0.45 to 1.45 (P<0.001) and the mean AOD 250 and AOD 500 increased from 38.5±25.9 to 83.5±48.4 μm (P<0.001) and 110.2±80.9 to 170.6±83.4 μm (P<0.001), respectively. The angles widened significantly in the opposite quadrant on UBM (AOD 250: 48.8±31.5–82.7±43.9 μm, P<0.001; AOD 500:117.2±65.5–172.2±81.7 μm; P<0.001), but the median gonioscopy grade remained unchanged. LPI significantly widened the anterior chamber angle in the quadrant with LPI and the quadrant furthest away in patients of CACG with established glaucomatous damage. This change was much better appreciated by the UBM than gonioscopy.

A phase II trial of AZD2171 (cediranib), an oral pan-VEGF receptor tyrosine kinase inhibitor, in patients with recurrent glioblastoma

Abstract: 2001 Background: AZD2171 (cediranib) is a potent, oral pan-VEGF receptor tyrosine kinase inhibitor with a half-life of 20 hours compatible with once-daily dosing. A primary target of AZD2171, VEGFR...

Human Tumor Xenografts Recurring after Radiotherapy Are More Sensitive to Anti–Vascular Endothelial Growth Factor Receptor-2 Treatment than Treatment-Naive Tumors

Abstract: The effects of antiangiogenic therapy on tumors relapsing after irradiation are not known To this end, we irradiated human tumors growing sc in nude mice with a single dose of 20 or 30 Gy Compared with primary (treatment-naive) xenografts, the growth rate of recurrent tumors was 16-fold slower, which is consistent with the known "tumor bed effect" For similar size tumors, recurrences had fewer functional vessels, a reduced vessel coverage by perivascular cells, and were more necrotic Placenta growth factor concentration was significantly lower in relapses, whereas vascular endothelial growth factor (VEGF) levels were similar between primary and recurrent tumors On the other hand, fibrillar collagen deposition was significantly increased in recurrent tumors This radiation-induced fibrosis was partially responsible for the slower growth of recurrences; the it injection of collagenase increased the growth rate of tumor relapses without affecting primary tumor growth The mouse-specific VEGF receptor 2-blocking antibody DC101 induced a 22-fold longer growth delay in recurrent tumors compared with treatment-naive tumors DC101 significantly decreased the interstitial fluid pressure and did not change the functional vessel density and perivascular cell coverage in both tumor variants Interestingly, DC101 induced a rapid (2 days after treatment initiation) and significant decrease in tumor cell proliferation in recurrent but not in primary tumors Thus, our results show that the stromal compartment and the response to antiangionenic therapy of primary and in-field recurrent tumors are significantly different Our findings suggest that antiangiogenic agents could be effective in the treatment of patients with relapses after radiotherapy

Antiangiogenic agents for the treatment of glioblastoma

Abstract: Glioblastomas are highly vascularized and, therefore, antiangiogenic agents are increasingly being explored as therapeutic options. This review summarizes the present data on antiangiogenic agents in glioblastoma treatment. The angiogenic pathway in gliomas and the proposed mechanisms of antiangiogenic agents are reviewed briefly, and details of the drugs in clinical trial are provided. In addition to their effects on blood vessels, these agents also have potent antiedema effects that may have therapeutic benefit. The review concludes with a discussion of the role of biomarkers and neuroimaging in the assessment of tumor response. Although preliminary studies of these drugs in glioblastoma have been promising, larger prospective trials that include survival as an end point will be required to determine the ultimate utility of this class of agents. It seems likely that a combination of antiangiogenesis agents with other cytotoxic therapies will be required to achieve maximal efficacy.

Antagonistic and antimicrobial activities of some bacterial isolates collected from soil samples.

Abstract: Thirty seven bacterial cultures isolated from soil samples obtained from different locations were tested for their antagonistic activity against some fungal pathogens, viz., Sclerotium rolfsii, Fusarium oxysporum and Rhizoctonia solani, causal agents of collar rot of sunflower, wilts and root rots, respectively. Among them, 5 bacterial strains, viz., A1 6 (Bacillus sphaericus), K1 24 (Pseudomonas fluorescens), M1 42 (Bacillus circulans), M1 66 (Bacillus brevis) and T1 22 (Bacillus brevis) showed positive antagonistic activity. M1 66 was the most effective in inhibiting mycelial growth of S. rolfsii in vitro followed by M1 42, T1 22, K1 24 and A1 6. Only one bacterial strain i.e. M1 42 exhibited antagonistic activity against F. oxysporum, and none of the bacterial strains gave positive activity against R. solani. Furthermore, antimicrobial activities of all the 5 strains were checked against different test organisms. These strains showed their extensive inhibition effect particularly against gram-positive test bacteria (Staphylococcus aureus and Bacillus subtilis) and the test fungal strain (Candida albicans). On the other hand, B. brevis M1 66 and B. brevis T1 22 strains had an inhibitory effect against gram positive and gram-negative test bacteria (Escherichia coli and Proteus vulgaris) as well as the test fungal strain.

Complete genome sequence of an isolate of Papaya ringspot virus from India.

Abstract: Both conventional and genetically engineered (transgenic) resistance strategies have been successfully deployed to manage Papaya ringspot virus (PRSV) in papaya in Taiwan and the USA [3]. The success of both resistance strategies depends on the genetic diversity of the PRSV population [3]. The PRSV genome is well characterized, and complete genome sequence of eleven PRSV isolates, one each from Hawaii and Mexico, two each from Brazil (two W isolates) and Thailand (one P isolate and one W isolate), and five isolates from Taiwan (four P isolates and one W isolate) are available [1, 2, 7, 8]. However, information on the complete genome sequence of PRSV from India is lacking. Here, we report the complete genome sequence of an isolate of PRSV (designated as PRSVDEL) from India and its comparison with other isolates. Provenance of the virus material

Study of methanol-induced phenotypic changes in a novel strain of Acinetobacter lwoffii.

Abstract: A Gram-negative bacterial strain designated LS2 isolated from Lahaul-Spiti valley of North India was shown to produce pink pigment while utilizing methanol as sole source of carbon and energy. Interestingly, pigment production was inducible in nature since the organism did not produce any pigment when grown on other carbon sources. Based on phenotypic and phylogenetic characterization the non-pigmented methylotroph was identified as a novel strain of Acinetobacter lwoffii MTCC 8288 (DQ144736). By means of spectral and mass analyses the pigment was characterized as bacterioruberin-like carotenoid molecule. Here, the carotenoid pigment may form an important part of the antioxidant defense mechanism against oxidative stress imparted by methanol. The methanol utilization pathway in strain LS2 was deciphered by showing the presence of functional methanol dehydrogenase and formaldehyde dehydrogenase genes. In addition, to investigate methanol induced physiological changes, comparative fatty acid profile was analysed and distinctive qualitative as well as quantitative differences in fatty acid content were observed. Therefore, we suggest that strain LS2 exhibiting such unique phenotypic property should be assigned a taxonomic position other than the pigmented and non-pigmented methylotrophs.

Characterization of Two Novel Biovar of Agrobacterium tumefaciens Isolated from Root Nodules of Vicia faba

Abstract: A total of eight strains of bacteria were isolated from the root nodule of Vicia faba on the selective media of Rhizobium. Two of these strains produced phenotypically distinct mucoid colonies (one slow growing and the other fast growing) and were examined using a polyphasic approach for taxonomic identification. The two strains (MTCC 7405 and MTCC 7406) turned out to be new strains of biovar 1 Agrobacterium rather than Rhizobium, as they showed growth on alkaline medium as well as on 2% NaCl and neither catabolized lactose as the carbon source nor oxidized Tween-80. The distinctness between the two strains was marked with respect to their growth on dextrose and the production of lysine dihydrolase, ornithine decarboxylase and DNA G + C content. 16S rDNA sequencing and their comparison with the 16S rDNA sequences of previously described agrobacteria as well as rhizobia strains confirmed the novelty of the two strains. Both of the strains clustered with strains of Agrobacterium tumefaciens in the 16S rDNA-based phylogenetic tree. The phenotypic and biochemical properties of the two strains differed from those of the recognized biovar of A. tumefaciens. It is proposed that the strains MTCC 7405 and MTCC 7406 be classified as novel biovar of the species A. tumefaciens (Type strains MTCC 7405 = DQ383275 and MTCC 7406 = DQ383276).