A New Begomovirus Species Causing Tomato Leaf Curl Disease in Patna, India

During December of 2007, a severe leaf curl disease of tomato (ToLCD) occurred in tomato-growing areas in the Patna District of Bihar, India. Viral DNA was isolated from symptomatic tomato plants (2) and begomovirus association was confirmed by PCR using DNA-A degenerate primers (3). Isolated viral DNA was restricted with KpnI and full-length genome was cloned in pUC18. DNA-β was amplified using degenerate primers (1) and cloned in pTZ57RT. Partial tandem repeats of viral genome and DNA-β could infect Nicotiana benthamiana and tomato through Agrobacterium-mediated inoculation. Infected test plants exhibited typical symptoms characteristic of ToLCD. Full-length viral genome (GenBank Accession No. EU862323) consists of 2,752 nt and showed the highest identity (85.8%) with Tomato leaf curl Laos virus-[Laos] (GenBank Accession No. AF195782). The satellite DNA-β component (GenBank Accession No. EU862324) consists of 1,349 nt and showed the highest identity (75.8%) with Tomato leaf curl Joydebpur betasatellite (GenBank Accession No. AJ966244). On the basis of the ICTV species demarcation criteria of 89% of DNA-A sequence identity, the present isolate was considered as a new begomovirus species and named Tomato leaf curl Patna virus (ToLCPaV). Since the isolated DNA-β satellite shares less than 78% identity, it is considered a new species of betasatellite and the name, Tomato leaf curl Patna betasatellite (ToLCPaB) is proposed. These results show that severe ToLCD in Patna is caused by a newly identified species of begomovirus and betasatellite. References: (1) R. W. Briddon et al. Mol. Biotechnol 20:315, 2002. (2) S. Chakraborty et al. Phytopathology 93:1485, 2003. (3) S. D. Wyatt and J. K. Brown. Phytopathology 86:1288, 1996.

Generation of Bessel beams using a terahertz quantum cascade laser

We report the generation of Bessel beams using polytetrafluoroethene conical lenses and a quantum cascade laser emitting at 2.8 THz. The formation of a central beam spot that retains its size over distances exceeding the characteristic Rayleigh range is demonstrated, and the power transport properties of these beams are compared with those obtained using parabolic reflectors. These lenses could provide an attractive alternative to parabolic reflectors for terahertz imaging applications where a large depth of focus and/or efficient and controllable coupling of radiation onto a small target are desirable.

Cervical spine motion during flexible bronchoscopy compared with the Lo-Pro GlideScope

BACKGROUND

The most appropriate device for tracheal intubation in patients with potential cervical spine injury remains controversial. We hypothesized that the Lo-Pro GlideScope (LP-G) videolaryngoscope would not cause significantly greater cervical spine movement than fibreoptic bronchoscopy even in the non-immobilized spine.

METHODS

Twenty-eight healthy adults requiring intubation for radiographic procedures were randomized to either the LP-G or the flexible bronchoscope (FB) devices. Continuous fluoroscopy was used to assess cervical spine movement during tracheal intubation. The point of maximum movement was compared with baseline for change in angulation between Occiput (Occ)-C1, Occ-C2, Occ-C4, Occ-C5, C1-2, C2-4, and C4-5. Measurements were made by two independent observers. The change in angulation was also measured for tongue pull and jaw thrust, manoeuvres for enlarging the pharyngeal space, before FB intubation.

RESULTS

LP-G resulted in greater cervical extension compared with FB for every angle calculated, statistically significant between Occ-C1 (P<0.05), Occ-C2 (P<0.05), and Occ-C4 (P<0.01). Tongue pull resulted in significantly less cervical spine motion than FB intubation at Occ-C1, Occ-C2, Occ-C4, and Occ-C5 (P<0.05). When jaw thrust was added to tongue pull, there was a tendency for greater movement than FB intubation at Occ-C1, Occ-C2, and Occ-C3. This was statistically significant at Occ-C1 and Occ-C3 (P<0.05) for one of the two observers.

CONCLUSIONS

During intubation under general anaesthesia, LP-G resulted in greater cervical movement than FB when no cervical immobilization was used in adults without cervical disease. Airway manoeuvres performed before FB, especially jaw thrust, also resulted in cervical spine movement.

Vertebral artery dissection with a normal-appearing lumen at multisection CT angiography: the importance of identifying wall hematoma

BACKGROUND AND PURPOSE

CT angiography (CTA) is widely used and may be the only vascular imaging technique ordered for emergent evaluation of neurovascular disease. With thin-section multisection CTA, the resolution of vessel wall imaging has improved. We describe cases of acute vertebral artery dissection (VAD) in which the only abnormality on CTA was a characteristic thickening of the wall of the V3 portion of the vertebral artery (VA). The arterial lumen at the dissection site was normal in caliber. This type of dissection is easily overlooked if only lumen-opacifying studies such as contrast MR angiography (MRA) or conventional angiography are performed. We highlight the importance of recognizing this finding, the "suboccipital rind" sign, in the V3 portion, a segment commonly affected in VAD. The purpose of our study was to review the CTA imaging characteristics of patients with VAD in the V3 portion compared with normal controls.

MATERIALS AND METHODS

Our imaging data base was reviewed for cases of acute VAD and the presence of a "suboccipital rind" sign. A control group of 50 patients was randomly recruited from a group of patients undergoing CTA. The VA luminal diameter, the wall thickness (total diameter-luminal diameter), and the ratio of luminal diameter/total diameter were measured along 5 adjacent V3 segments and were compared between the 2 groups.

RESULTS

There was no evidence of luminal tapering or narrowing in the dissected VAs compared with controls (P = .1). The average wall thickness of the dissection group was 2.96 mm greater than that for the control group (P < .001; 95% confidence interval, 2.6-3.3). There was a significant difference in the ratio of lumen diameter/lumen+wall diameter in dissected segments compared with controls (P < .001).

CONCLUSIONS

Cross-sectional vascular imaging is often performed with multisection helical CTA for a variety of concerns, some without neurologic symptoms. Our study confirms that in cases of the "suboccipital rind" sign, the lumen appears normal in caliber, with wall thickening as the only imaging sign of VAD. In our center, this clinically occult VAD would influence management, with patients usually treated with antiplatelet agents. We caution against using only luminal-opacifying techniques such as contrast-enhanced MRA or conventional angiography to exclude VAD because they are limited in the evaluation of mural hematoma.

Phytoremediation efficiency of Portulaca tuberosa rox and Portulaca oleracea L. naturally growing in an industrial effluent irrigated area in Vadodra, Gujrat, India

Phytoremediation is a novel, solar-driven and cost-effective technology for the remediation of heavy metal contaminated environments through exploitation of plants ability to accumulate heavy metals in their harvestable shoot parts. In the present investigation, we collected plants of two species of Portulaca i.e. P. tuberosa and P. oleracea from field sites in Vadodra, Gujrat, India. At one site, field was being irrigated with industrial effluent while at other with tube well water. Analysis of heavy metals was performed in industrial effluent, tube well water, soils irrigated with them, and in different parts viz., roots, stem, leaves and flowers of the plant samples. Industrial effluent and soil irrigated with it had very high level of heavy metals (Fe, Zn, Cd, Cr and As) as compared to the tube well water and soil irrigated with that. Plants of both the species growing in effluent irrigated soils showed high accumulation of metals in all plant parts with the maximum being in roots and the least in flowers. Interestingly, both species of Portulaca hyperaccumulated more than one heavy metal viz., Cd, Cr and As. The total shoot concentrations (microg g(-1) dw) of Cd, Cr and As in P. tuberosa were 1,571, 7,957 and 3,118, respectively while in P. oleracea, these were 1,128, 7,552 and 2,476, respectively. Portulaca plants have good biomass and high regeneration potential; hence appear to be suitable for the remediation of effluent (metal) contaminated areas.

Isolation and characterization of high quality DNA from marine benthic macroalgae

The isolation of high quality DNA is essential for many molecular biology applications including polymerase chain reaction (PCR) and endonuclease restriction digestion based techniques. An easy and inexpensive protocol has been developed for extracting genomic DNA from seven species of algae viz. Lola capillaries, Enteromorpha intestinalis, Ulva lactuca and Rhizoclonium sp belonging to Chlorophyceae, Catenella nipae, Polysiphonia mollis belonging to Rhodophyceae and Dictyota ceylanica belonging to Phaeophyceae group were collected from the coastal regions of Sunderban delta in West Bengal, India dominantly growing on mud flats, bark of different mangrove trees, pneumatophores, stilt roots, concrete surfaces, wooden and bamboo poles, sides of the boats and other water vehicles inundated during high tides. The DNA was found suitable for restriction endonuclease digestion and PCR amplification with randomely amplified polymorphic DNA (RAPD) primers. The A260/A280 ratio of 1.15 0.14 to 1.94 indicated little contamination from proteins and polysaccharides. The PCR amplification with RAPD primers showed its suitability in PCR based techniques and the restriction digestion with Eco RV confirmed its suitability for hybridization based techniques. The protocol is equally good for isolating DNA from both fresh as well as preserved materials.

Comparison of arsenic concentrations in simultaneously-collected groundwater and aquifer particles from Bangladesh, India, Vietnam, and Nepal

One of the reasons the processes resulting in As release to groundwater in southern Asia remain poorly understood is the high degree of spatial variability of physical and chemical properties in shallow aquifers. In an attempt to overcome this difficulty, a simple device that collects groundwater and sediment as a slurry from precisely the same interval was developed in Bangladesh. Recently published results from Bangladesh and India relying on the needle-sampler are augmented here with new data from 37 intervals of grey aquifer material of likely Holocene age in Vietnam and Nepal. A total of 145 samples of filtered groundwater ranging in depth from 3 to 36 m that were analyzed for As (1-1000 mug/L), Fe (0.01-40 mg/L), Mn (0.2-4 mg/L) and S (0.04-14 mg/L) are compared. The P-extractable (0.01-36 mg/kg) and HCl-extractable As (0.04-36 mg/kg) content of the particulate phase was determined in the same suite of samples, in addition to Fe(II)/Fe ratios (0.2-1.0) in the acid-leachable fraction of the particulate phase. Needle-sampler data from Bangladesh indicated a relationship between dissolved As in groundwater and P-extractable As in the particulate phase that was interpreted as an indication of adsorptive equilibrium, under sufficiently reducing conditions, across 3 orders of magnitude in concentrations according to a distribution coefficient of 4 mL/g. The more recent observations from India, Vietnam and Nepal show groundwater As concentrations that are often an order of magnitude lower at a given level of P-extractable As compared to Bangladesh, even if only the subset of particularly reducing intervals characterized by leachable Fe(II)/Fe >0.5 and dissolved Fe >0.2 mg/L are considered. Without attempting to explain why As appears to be particularly mobile in reducing aquifers of Bangladesh compared to the other regions, the consequences of increasing the distribution coefficient for As between the particulate and dissolved phase to 40 mL/g for the flushing of shallow aquifers of their initial As content are explored.

Comparison of arsenic concentrations in simultaneously-collected groundwater and aquifer particles from Bangladesh, India, Vietnam, and Nepal

One of the reasons the processes resulting in As release to groundwater in southern Asia remain poorly understood is the high degree of spatial variability of physical and chemical properties in shallow aquifers. In an attempt to overcome this difficulty, a simple device that collects groundwater and sediment as a slurry from precisely the same interval was developed in Bangladesh. Recently published results from Bangladesh and India relying on the needle-sampler are augmented here with new data from 37 intervals of grey aquifer material of likely Holocene age in Vietnam and Nepal. A total of 145 samples of filtered groundwater ranging in depth from 3 to 36 m that were analyzed for As (1-1000 mug/L), Fe (0.01-40 mg/L), Mn (0.2-4 mg/L) and S (0.04-14 mg/L) are compared. The P-extractable (0.01-36 mg/kg) and HCl-extractable As (0.04-36 mg/kg) content of the particulate phase was determined in the same suite of samples, in addition to Fe(II)/Fe ratios (0.2-1.0) in the acid-leachable fraction of the particulate phase. Needle-sampler data from Bangladesh indicated a relationship between dissolved As in groundwater and P-extractable As in the particulate phase that was interpreted as an indication of adsorptive equilibrium, under sufficiently reducing conditions, across 3 orders of magnitude in concentrations according to a distribution coefficient of 4 mL/g. The more recent observations from India, Vietnam and Nepal show groundwater As concentrations that are often an order of magnitude lower at a given level of P-extractable As compared to Bangladesh, even if only the subset of particularly reducing intervals characterized by leachable Fe(II)/Fe >0.5 and dissolved Fe >0.2 mg/L are considered. Without attempting to explain why As appears to be particularly mobile in reducing aquifers of Bangladesh compared to the other regions, the consequences of increasing the distribution coefficient for As between the particulate and dissolved phase to 40 mL/g for the flushing of shallow aquifers of their initial As content are explored.

To dope Mn2+ in a semiconducting nanocrystal

It has been an outstanding problem that a semiconducting host in the bulk form can be doped to a large extent, while the same host in the nanocrystal form is found to resist any appreciable level of doping rather stubbornly, this problem being more acute in the wurtzite form compared to the zinc blende one. In contrast, our results based on the lattice parameter tuning in a Zn(x)Cd(1-x)S alloy nanocrystal system achieves approximately 7.5% Mn(2+) doping in a wurtzite nanocrystal, such a concentration being substantially higher compared to earlier reports even for nanocrystal hosts with the "favorable" zinc-blende structure. These results prove a consequence of local strains due to a size mismatch between the dopant and the host that can be avoided by optimizing the composition of the alloyed host. Additionally, the present approach opens up a new route to dope such nanocrystals to a macroscopic extent as required for many applications. Photophysical studies show that the quantum efficiency per Mn(2+) ion decreases exponentially with the average number of Mn(2+) ions per nanocrystal; en route, a high quantum efficiency of approximately 25% is achieved for a range of compositions.

Early diagnosis of pancreatic cancer: neutrophil gelatinase-associated lipocalin as a marker of pancreatic intraepithelial neoplasia

Pancreatic cancer is a highly lethal malignancy with a dismal 5-year survival of less than 5%. The scarcity of early biomarkers has considerably hindered our ability to launch preventive measures for this malignancy in a timely manner. Neutrophil gelatinase-associated lipocalin (NGAL), a 24-kDa glycoprotein, was reported to be upregulated nearly 27-fold in pancreatic cancer cells compared to normal ductal cells in a microarray analysis. Given the need for biomarkers in the early diagnosis of pancreatic cancer, we investigated the expression of NGAL in tissues with the objective of examining if NGAL immunostaining could be used to identify foci of pancreatic intraepithelial neoplasia, premalignant lesions preceding invasive cancer. To examine a possible correlation between NGAL expression and the degree of differentiation, we also analysed NGAL levels in pancreatic cancer cell lines with varying grades of differentiation. Although NGAL expression was strongly upregulated in pancreatic cancer, and moderately in pancreatitis, only a weak expression could be detected in the healthy pancreas. The average composite score for adenocarcinoma (4.26+/-2.44) was significantly higher than that for the normal pancreas (1.0) or pancreatitis (1.0) (P<0.0001). Further, although both well- and moderately differentiated pancreatic cancer were positive for NGAL, poorly differentiated adenocarcinoma was uniformly negative. Importantly, NGAL expression was detected as early as the PanIN-1 stage, suggesting that it could be a marker of the earliest premalignant changes in the pancreas. Further, we examined NGAL levels in serum samples. Serum NGAL levels were above the cutoff for healthy individuals in 94% of pancreatic cancer and 62.5% each of acute and chronic pancreatitis samples. However, the difference between NGAL levels in pancreatitis and pancreatic cancer was not significant. A ROC curve analysis revealed that ELISA for NGAL is fairly accurate in distinguishing pancreatic cancer from non-cancer cases (area under curve=0.75). In conclusion, NGAL is highly expressed in early dysplastic lesions in the pancreas, suggesting a possible role as an early diagnostic marker for pancreatic cancer. Further, serum NGAL measurement could be investigated as a possible biomarker in pancreatitis and pancreatic adenocarcinoma.

Avonex Combination Trial in relapsing—remitting MS: rationale, design and baseline data

Objective To review the rationale, design and baseline data of the Avonex Combination Trial (ACT), an investigator-run study of intramuscular interferon beta-1a (IM IFNβ-1a) combined with methotrexate (MTX) and/or IV methylprednisolone (IVMP) in relapsing—remitting multiple sclerosis (RRMS) patients with continued disease activity on IM IFNβ-1a monotherapy.

Methods Eligibility criteria included RRMS, Expanded Disability Status Scale score 0—5.5, and ≥1 relapse or gadolinium-enhancing MRI lesion in the prior year while on IM IFNβ-1a monotherapy. Subjects continued IFNβ-1a 30 mcg IM weekly and were randomized in a 2 × 2 factorial design to adjunctive weekly placebo or MTX 20 mg PO, with or without IVMP 1000 mg/day for three days every other month. ACT was industry-supported, and collaboratively designed and governed by an Investigator Steering Committee with independent Advisory and Data Safety Monitoring Committees. Study operations, MRI analysis and aggregated data were managed by the Cleveland Clinic MS Academic Coordinating Center.

Results In total 313 subjects were enrolled with clinical and MRI characteristics typical of RRMS. Most subjects (86.9%) qualified with a clinical relapse, with or without an enhancing MRI lesion, in the preceding year. At baseline, 21.4% had enhancing lesions, and 5.1% had anti-IFNβ neutralizing antibodies. ACT's management and operational structures functioned well.

Conclusion This study provides an innovative model for academic—industry collaborative MS research and will enhance understanding of the utility of combination therapy for RRMS patients with continued disease activity on an established first-line treatment. Multiple Sclerosis 2008; 14: 370—382. http://msj.sagepub.com

Supervirulent pseudorecombination and asymmetric synergism between genomic components of two distinct species of begomovirus associated with severe tomato leaf curl disease in India

Isolates of two distinct begomovirus species, the severe strain of the species Tomato leaf curl New Delhi virus (tomato leaf curl New Delhi virus-[India:New Delhi:Severe:1992]; ToLCNDV-[IN:ND:Svr:92], bipartite) and the Varanasi strain of the species Tomato leaf curl Gujarat virus (tomato leaf curl Gujarat virus-[India:Varanasi:2001]; ToLCGV-[IN:Var:01], mono/bipartite) infect tomato (Lycopersicon esculentum) and cause severe yield losses in northern India. This study investigated the infectivity properties of genomic components of these two species. Both pseudorecombinants were infectious in Nicotiana benthamiana, Nicotiana tabacum and L. esculentum. Enhanced pathogenicity was observed when DNA-A of ToLCNDV-[IN:ND:Svr:92] was trans-complemented with ToLCGV-[IN:Var:01] DNA-B, and was consistently associated with an increase in accumulation of ToLCGV-[IN:Var:01] DNA-B. Mixed infection of ToLCNDV-[IN:ND:Svr:92] and ToLCGV-[IN:Var:01] always showed extremely severe symptoms, suggesting a synergistic interaction between these two viruses. Southern blot analysis of viral DNAs from infected plants showed a significantly higher level of accumulation of both ToLCNDV components and DNA-B of ToLCGV-[IN:Var:01] with no alteration to levels of DNA-A of ToLCGV-[IN:Var:01]. Symptom development and/or higher infectivity of the supervirulent pseudorecombinants correlated with the increased levels of DNA-B accumulation. Protoplast replication assays revealed that enhanced infectivity by the pseudorecombinant occurred at the level of replication, as DNA-A of ToLCNDV-[IN:ND:Svr:92] enhanced ToLCGV-[IN:Var:01] DNA-B replication, whose accumulation was in turn increased by ToLCGV-[IN:Var:01] DNA-A. This is the first report demonstrating a virulent pseudorecombinant between two distinct species of begomoviruses that infect tomato, and is the second report on synergism between begomoviruses. The results revealed that ToLCGV-[IN:Var:01] DNA-B is capable of associating with different DNA-A components, despite having different iteron sequences.

Alberta Stroke Program Early CT Scoring of CT perfusion in early stroke visualization and assessment

BACKGROUND AND PURPOSE

Qualitative CT perfusion (CTP) assessment by using the Alberta Stroke Program Early CT Score (ASPECTS) allows rapid calculation of infarct extent for middle cerebral artery infarcts. Published thresholds exist for noncontrast CT (NCCT) ASPECTS, which may distinguish outcome/complication risk, but early ischemic signs are difficult to detect. We hypothesized that different ASPECTS thresholds exist for CTP parameters versus NCCT and that these may be superior at predicting clinical and radiologic outcome in the acute setting.

MATERIALS AND METHODS

Thirty-six baseline acute stroke NCCT and CTP studies within 3 hours of symptoms were blindly reviewed by 3 neuroradiologists, and ASPECTS were assigned. Treatment response was defined as major neurologic improvement when a > or =8-point National Institutes of Health Stroke Scale improvement at 24 hours occurred. Follow-up NCCT ASPECTS and 90-day modified Rankin score (mRS) were radiologic and clinical reference standards. Receiver operating characteristic curves derived optimal thresholds for outcome.

RESULTS

Cerebral blood volume and NCCT ASPECTS had similar radiologic correlations (0.6 and 0.5, respectively) and best predicted infarct size in the absence of major neurologic improvement. A NCCT ASPECT threshold of 7 and a cerebral blood volume threshold of 8 discriminated patients with poor follow-up scans (P < .0002 and P = .0001) and mRS < or =2 (P = .001 and P < .001). Only cerebral blood volume predicted major neurologic improvement (P = .02). Interobserver agreement was substantial (intraclass correlation coefficient, 0.69). Cerebral blood volume ASPECTS sensitivity, specificity, positive predictive value, and negative predictive value for clinical outcome were 60%, 100%, 100%, and 45%, respectively. No patients with cerebral blood volume ASPECTS <8 achieved good clinical outcome.

CONCLUSION

Cerebral blood volume ASPECTS is equivalent to NCCT for predicting radiologic outcome but may have an additional benefit in predicting patients with major neurologic improvement.

Zero kinetic energy spectroscopy of hydroquinone-water (1:1) complex: A probe for conformer assignment

Zero kinetic energy (ZEKE) photoelectron spectroscopy of the hydroquinone-water (HQW) complex was carried out to characterize its S(1)-S(0) resonantly enhanced multiphoton ionization (REMPI) spectrum in terms of the cis and trans conformers. The ZEKE spectra of the hydroquinone isomers show differences in the Franck-Condon (FC) activity of a few ring modes, viz., modes 15, 9b, and 6b, due to the different symmetries of the two isomers. These modes were used as a "diagnostic tool" to carry out the categorical assignment of the REMPI spectrum of the HQW complex. It was found that the FC activity of these diagnostic modes in the cationic ground state (D(0)) of the water complex is similar as that of the monomer. The two lowest energy transitions in the REMPI spectrum of the water complex, 33,175 and 33,209 cm(-1), were reassigned as the band origins of the cis and trans hydroquinone-water complexes, which is opposite of the previous assignment. The intermolecular stretching mode (sigma) of the complex shows a long progression, up to v(')=4, in the cationic ground state and is strongly coupled to other observed ring modes. The Franck-Condon factors for different members in the progression were calculated using the potential energy surfaces computed ab initio. These agree well with the observed intensity patterns in the progression. The ionization potential of the trans and cis complexes was determined to be 60,071+/-4 and 60,024+/-4 cm(-1), respectively.

Nasopharyngeal liposarcoma MRI imaging features and a review of the literature

We present a case of liposarcoma in a 37-year-old female with a chronic history of nasal stuffiness. MR imaging revealed a fatty lesion in the nasopharynx. Subsequent tissue sampling and histopathology demonstrated features consistent with a liposarcoma.

A New Begomovirus Species Causing Leaf Curl Disease of Radish in India

Leaf curl disease of radish (RLCD) was observed for the first time in India in commercial fields and kitchen gardens of the Varanasi District and adjoining areas of eastern Uttar Pradesh during November 2003. Infected plants exhibited typical upward and downward leaf curling, leaf distortion, reduction of leaf area, and conspicuous enations on the underside of the leaves. Incidence of RLCD was estimated to be between 10 and 40% depending on the cultivars used. Electron microscopic observation revealed typical geminate particles in infected leaf samples. The causal virus could be transmitted to radish cv. Minu Early by whiteflies (Bemisia tabaci) and grafting. Inoculated plants developed symptoms similar to those observed in naturally infected radish plants. Viral DNA was isolated from artificially inoculated symptomatic radish plants (4) followed by concentration of super-coiled DNA by alkaline denaturation (1). The presence of a geminivirus was confirmed by PCR using DNA-A degenerate primers (3), and a 1.5-kb amplified product was obtained from six artificially and three naturally infected plants. Amplification of the full-length DNA-A was achieved using a primer combination derived from sequences obtained from a 1.5-kb amplicon. Amplification of 1.3-kb DNA-β sequences was achieved using specific primers (2) in three infected plants. Sequence analysis revealed that DNA-A (GenBank Accession No. EF 175733) contained 2,756 nt and DNA-β contained 1,358 nt (GenBank Accession No. EF 175734). DNA-A of the causal virus shares 87.7% identity with Tomato leaf curl Bangladesh virus (GenBank Accession No. AF 188481) and 62% identity with Mungbean yellow mosaic India virus (GenBank Accession No. AF126406). The begomovirus DNA-A sequence associated with RLCD contained seven open reading frames (AV1, AV2, AC1, AC2, AC3, AC4, and AC5). The DNA-β associated with RLCD shared the highest nucleotide sequence identity (84.9%) with DNA-β of Tobacco leaf curl virus isolate NIB 12-1 (GenBank Accession No. AJ316033) reported from Pakistan. Despite exhaustive attempts to amplify a putative viral B-component using degenerate primers based on the intergenic region sequence of the DNA-A or sequences that are highly conserved for other begomoviruses, no DNA-B component was detected. On the basis of DNA-A sequence analysis, the ICTV species demarcation criteria of 89% sequence identity, and genome organization, the virus causing RLCD should be considered a new Begomovirus species, for which the name Radish leaf curl virus (RLCV) is proposed. To our knowledge, this is the first report of the association of a Begomovirus with a disease of radishes in India. References: (1) H. C. Birnboim and J. Doly. Nucleic Acids Res. 7:1513, 1979. (2) R. W. Briddon et al. Mol. Biotechnol. 20:315, 2002. (3) M. R. Rojas et al. Plant Dis. 77:340, 1993. (4) K. M. Srivastava et al. J. Virol. Methods 51:297, 1995.

Synthesis of CdSe nanocrystals in a noncoordinating solvent: effect of reaction temperature on size and optical properties

Colloidal synthesis of high quality CdSe nanocrystals with controllable size and tunable properties have been one of the most important topics of research over the last decade, in view of its huge technological potentials. CdSe is one of the most studied nanocrystals of this category because of its photoluminescence tunability across the visible spectrum. We have synthesized CdSe nanocrystals using CdO precursor in a noncoordinating solvent and studied the effect of the reaction temperature on the size and optical properties of the nanocrystals. The size of the nanocrystals could be varied systematically in the range of 3.5 to 6.6 nm diameter with a remarkably narrow size distribution by controlling only the reaction temperature, without any need for a post-synthesis processing. The band gap and the corresponding band edge emission could be tuned across the entire visible range by tuning the size of the nanocrystals. The narrow width of the photoluminescence emissions of different colours (blue to red) make these nanocrystals a potential candidate for different optical and optoelectronic devices.

Distribution and possible source of trace elements in the sediment cores of a tropical macrotidal estuary and their ecotoxicological significance

The paper presents the first document regarding concentration, distribution and possible sources of selected trace elements (Cu, Fe, Mn, Zn, Cr, Co, Ni, Pb, Al, B and Ba) in core sediments (<63 micro particle size) from the lower stretch of Hugli (Ganges) estuary, northeast coast of Bay of Bengal by ICP-AES and EDXRF to evaluate geochemical processes influencing their distribution and possible environmental consequences. The levels of elements showed a wide range of variations in different core depths, in upper and lower intertidal zones as well as among three sampling stations. The most interesting feature of the study is the downward increase of concentrations of majority of the elements reaching overall maximum values at a depth of 20-28 cm in upper littoral zone of the site located in the extreme downstream stretch of the estuary. Values of organic carbon showed very strong positive correlations with most of the elements as revealed by correlation matrix (r) values. The interelemental relationship revealed the identical behavior of element during its transport in the estuarine environment. The overall variation in concentration can be attributed to differential discharge of untreated effluents originating from industrial, agricultural, and aquacultural sources as well as from domestic sewage along with the fishing and boating activities. The resulting compositional dataset was tested by principal component analyses and cluster analyses. Pollution load index (PLI) and index of Geoaccumulation (Igeo) revealed overall low values but the enrichment factors (EFs) for Pb were typically high for all the stations. The mean concentrations of Zn and to some extent Cu exceeded the Effects Range-Low (ER-L) values in the majority of the cases indicating that there may be some ecotoxicological risk to organisms living in sediments. The concentration of the trace elements reported in this work is useful as baselines for comparison in future sediment quality studies.