Laser photoacoustic spectra of Sm3+ ion in Sm2O3 and SmCl3.6H2O in the spectral profile 484-542 nm

Microphone based photoacoustic (PA) spectrometer to study solids in powder form was designed and fabricated. Laser PA spectra of Sm3+ ion in Sm2O3 and SmCl3.6H2O microcrystalline powders were recorded first time in 484-542 nm spectral region at room temperature. Analysis of these PA spectra shows new information on the Stark components of ground and excited states of Sm3+ ion. A comparison of Stark energy levels of Sm3+ ion in both oxide and hexahydrated chloride hosts is presented here.

Field Evaluation of Tomato spotted wilt virus Resistance in Transgenic Peanut (Arachis hypogaea)

Spotted wilt, caused by Tomato spotted wilt virus (TSWV), is a devastating disease of many crops including peanut (Arachis hypogaea). Because the virus has a broad host range and is spread by ubiquitous thrips, disease management by traditional means is difficult. Developing new peanut cultivars with resistance to TSWV presents a significant challenge since existing genetic resistance in peanut germ plasm is limited. A genetic engineering approach appears to have great potential for resistance enhancement to TSWV. Transgenic peanut progenies that expressed the nucleocapsid protein of TSWV were subjected to natural infection of the virus under field conditions during the growing seasons of 1999 and 2000 in Tifton, GA, and in three locations (Tifton, GA, Marianna, FL, and Headland, AL) in 2001. Significantly lower incidence of spotted wilt was observed for the transgenic progeny in comparison to the nontransgenic checks in the field (in multiple years and locations) as well as during challenge inoculation under controlled environmental conditions. This transgenic event could potentially be used in a traditional breeding program to enhance host resistance.

First Report of Association of Tomato leaf curl virus-New Delhi with Yellow Mosaic Disease of Luffa cylindrica in India

Sponge gourd (Luffa cylindrica), an important cucurbitaceous vegetable in India, is affected by a disease (2) causing yellow spots on newly emerged leaves, mosaic, mild leaf curling and distortion, small leaves, and misshapen fruits. Nearly 100% of sponge gourd plants were symptomatic in Delhi. Geminivirus-like particles were observed with electron microscopy of uranyl acetate-stained leaf-dip preparations of the diseased plants collected from experimental fields at the Indian Agricultural Research Institute in New Delhi during May and June of 2002. The virus was transmitted by the whitefly (Bemisia tabaci) to sponge and ridge gourd (L. acutangula) after an acquisition and inoculation access period of 24 h each. Whitefly-inoculated plants produced typical yellow mosaic symptoms and contained geminate particles. Nucleic acid extracted from the field-infected and experimentally infected plants hybridized with ³²P-labeled probe to DNA-A of Indian cassava mosaic virus, suggesting association of a begomovirus. The viral DNA, isolated by the alkali denaturation method (1) from the experimentally infected sponge gourd plants, was cloned in pBS SK+ at the EcoRI site. A clone with an insert of 2,658 bp was sequenced (GenBank Accession Nos. AJ557219, AJ555488, and AY309957) which shared 89.6 to 95.1% identity with the DNA-A of different strains of Tomato leaf curl virus-New Delhi (ToLCV-NDe). The highest sequence identity (95.1%) was with the severe strain of ToLCV-NDe (GenBank Accession No. U15015). The data suggest that the begomovirus associated with the yellow mosaic disease of L. cylindrica in India is a putative strain of ToLCV-NDe. Reference: (1) K. M. Srivastava et al. J. Virol. Methods 51:297, 1995. (2) A. Varma and B. K. Giri. Virus diseases. Pages 225-245 in: Cucurbits. N. M. Nayar and T. A More, eds. Oxford and IBH Publishing House Private Ltd., New Delhi, India, 1998.

First Report of Natural Infection of Luffa acutangula by Watermelon bud necrosis virus in India

In August 2002, ridge gourd (Luffa acutangula) plant samples exhibiting yellowing of leaves were collected from the experimental farm of Tamil Nadu Agricultural University, Coimbatore, India. Mechanical inoculations of ridge gourd seedlings using the above samples resulted in chlorotic spots on inoculated leaves and vein clearing followed by chlorotic rings and yellow netting along veins of newly developed leaves. The virus was reisolated from the chlorotic spots of the seedlings. Extracts from the field samples as well as mechanically inoculated seedlings reacted with antiserum to Watermelon silver mottle virus (WSMoV) in direct antigen coating enzyme-linked immunosorbent assay, suggesting the association of a tospovirus belonging to WSMoV serogroup (2). Symptomatic leaves from the second mechanical passage exhibiting yellow netting along the veins were subjected to reverse transcription-polymerase chain reaction (1) to identify the genus Tospovirus. Using the primer pair (5'TCTGTCCT(C/T) TTGAA (G/T) GTCCA3' and 5'AGAGCAATCGAGGCGCT3') derived from the conserved sequences of Groundnut bud necrosis virus (GBNV) and WSMoV, part of the nucleocapsid (N) protein gene and the complete noncoding region upstream of the N gene's coding sequence were cloned and sequenced. Comparative sequence analysis of 291-bp region of the N gene revealed that the genus Tospovirus infecting ridge gourd shared maximum identity both at nucleotide (94%) and amino acid (97%) levels with the corresponding region of Watermelon bud necrosis virus (WBNV), which is a distinct species of WSMoV serogroup infecting watermelon in India (1). In contrast, only 76 to 81% and 82% identity at nucleotide and amino acid levels, respectively, was observed with the corresponding region of the N genes of GBNV and WSMoV. Natural infection of WBNV in cucurbits except watermelon in India is not known. To our knowledge, this is the first report of natural infection of ridge gourd by WBNV. References: (1) R. K. Jain et al. Arch. Virol. 143:1637, 1998. (2) J. W. Moyer. Tospoviruses (Bunyaviridae). Pages 1803-1807 in: Encyclopedia of Virology. A. Granoff and R. G. Webster, eds. Academic Press, New York, 1999.

Differential Response of Selected Peanut (Arachis hypogaea) Genotypes to Mechanical Inoculation by Tomato spotted wilt virus

Screening of peanut germ plasm for resistance to Tomato spotted wilt virus (TSWV) has been largely inefficient due to the lack of a screening technique based on mechanical transmission of the virus under controlled environmental conditions. We have studied the reaction of three peanut cultivars (Georgia Green, Georgia Runner, C-99R) and one breeding line (C11-2-39) using a highly efficient mechanical inoculation procedure. The disease response was studied at two temperature regimes, 25 to 30°C (low temperature) and 30 to 37°C (high temperature). Based on percent transmission, symptomatology, distribution of TSWV, and relative levels of TSWV nucleocapsid (N) protein, Georgia Runner and Georgia Green were found to be susceptible, whereas C-99R and C11-2-39 were resistant. Of the four genotypes tested, C11-2-39 had the highest level of resistance to TSWV. The results correlated with the field performance of the genotypes except in the case of Georgia Green, which could not be distinguished from TSWV-susceptible Georgia Runner. Exposure of the inoculated plants to higher temperature (30 to 37°C) resulted in a better resistant response as reflected by reduced systemic infection, localized symptom expression, restricted viral movement, and reduced levels of TSWV antigen. To our knowledge, this is the first report of differential response of peanut genotypes to TSWV using mechanical inoculation. The four peanut genotypes should be useful as reference standards for the initial screening and identification of sources of TSWV resistance in peanut germ plasm.

Evolutionary principles for generating protein mimetics: directed assembly of peptide loops on topological templates

A novel methodology for the reversible competitive condensation of peptide loops to chemoreactive topological templates is presented.

Evolutionary principles for generating protein mimetics: directed assembly of peptide loops on topological templates

A novel methodology for the reversible competitive condensation of peptide loops to chemoreactive topological templates is presented.

Factors Affecting Mechanical Transmission of Tomato spotted wilt virus to Peanut (Arachis hypogaea)

Evaluation of peanut germ plasm for Tomato spotted wilt virus (TSWV) resistance has been slowed by the difficulty in achieving a high rate of mechanical transmission of the virus to peanut. In this study, improvements were made and a highly efficient mechanical transmission protocol was developed. Several factors that affect the transmission efficiency were identified. Use of two antioxidants (sodium sulfite and mercaptoethanol) and two abrasives (Celite and Carborundum) and application of the inoculum by rubbing with a cotton swab dipped in the inoculum as well as pricking with an inoculation needle resulted in a significantly higher transmission rate. The most susceptible growth stage of peanut to TSWV inoculation was 2 to 3 days after germination (6 to 7 days after planting). The inoculation protocol consistently resulted in a higher percentage of infected plants from different sources of inoculum such as infected peanut, tobacco, and tomato.

Outbreak of Tomato spotted wilt virus in Tomato in Kenya

Tomato spotted wilt virus (TSWV) of the genus Tospovirus, family Bunyaviridae (1), causes an economically important virus disease in tomato in several parts of the world. The virus has a wide host range that includes numerous crops and weeds and is transmitted by at least seven species of thrips. Tomato crops in the Subukia, Bahati, and Kabazi areas of the Nakuru District in Kenya were affected by a disease suggestive of TSWV infection during the November 1999 to March 2000 tomato-growing season. Farmers reported up to 80% losses of their potential yields. Characteristic symptoms were noticed on fruits, especially when they were green. Distinct concentric rings on fruits, which later turned into brown, uneven ripening, were the most visible symptoms. Foliage did not develop pronounced symptoms, but mild bronzing was observed in a few cultivars. However, foliage senesced prematurely, starting with older leaves. Foliar symptoms were mistaken for blight infection, and as a result, excessive fungicides were applied that failed to manage the disease. To test for TSWV infection, tomato leaf samples collected from the fields were tested initially with a TSWV test kit (HortiTech, Horticulture Research International, Wellesbourne, UK), and the results were confirmed by double-antibody sandwich-enzyme-linked immunosorbent assay with antibodies from Agdia Inc. (Elkhart, IN). Further molecular characterization was done using reverse transcription-polymerase chain reaction (RT-PCR). Total RNA was extracted from symptomatic leaves of tomato cv. Money Maker using the RNeasy mini kit (Qiagen Inc., Valencia, CA). Using primers 5' TTAAGC AAGTTCTGTGAG 3' and 5' ATGTCTAAGGTTAAGCTC 3' specific to the nucleoprotein (N) gene of TSWV, the N gene was amplified by RT-PCR (2). A 777-bp product of the expected size was obtained from symptomatic plants, whereas no amplification was obtained from noninfected tomato. The PCR product was cloned into pGEM-T Easy (Promega, Madison, WI) and sequenced. A search of GenBank revealed a sequence identity of 95 to 99% with the N genes of known TSWV isolates. To our knowledge, this is the first report TSWV infection of tomato in Kenya. Considering its wide host range, future surveys should be directed toward estimating its incidence in tomato and other TSWV-susceptible crops, such as Irish potatoes, pepper, peanut (groundnut), beans, and a wide variety of ornamental cut flowers in Kenya. References: (1) J. W. Moyer. Tospoviruses (Bunyaviridae). Pages 1803-1807 in: Encyclopedia of Virology. A. Granoff and R. G. Webster, eds. Academic Press, San Diego, CA, 1999. (2) Jain et al. Plant Dis. 82:900, 1998.

First Report of Cabbage leaf curl virus (Family Geminiviridae) in Georgia

Cabbage and collard greens were inflicted with a previously undescribed virus-like disease during the fall 2000. Symptoms on leaves were yellow spots, vein clearing, mosaic, curling, and puckering. Symptomatic plants were widespread in Brooks, Colquitt, Grady, and Pierce counties in Georgia. Disease incidence ranged from 10 to 20% in the majority of the fields surveyed but some fields had 100% incidence. Fields were heavily infested by Bemisia argentifolii and the symptoms were suggestive of a whitefly-transmitted geminivirus infection. A polymerase chain reaction (PCR)-based diagnostic test for geminivirus was conducted. Total DNA was extracted from symptomatic cabbage and collard green plants collected from commercial fields. The two primers, 5'-GCCCACATYGTCTTYCCNGT-3' and 5'- GGCTTYCTRTACATRGG-3' (2,3), are "universal" for genus Begomovirus of family Geminiviridae. The primer pair could amplify a part of the replicase-associated protein and coat protein and the complete common region of DNA-A. The PCR gave a DNA band of expected size (1.1 kb) from both symptomatic cabbage and collard green samples, whereas no such product was obtained from healthy samples, suggesting that the causal agent could be a geminivirus. To establish the identity of the virus, the 1.1 kb PCR product was cloned into pGEM-T Easy (Promega) and sequenced. GenBank search showed that the geminivirus isolated in Georgia was most closely related (98% sequence identity) to Cabbage leaf curl virus (accession number U65529) reported from Florida (1). The virus was mechanically transmitted to healthy cabbage and collard green plants under experimental conditions. To our knowledge, this is the first report of Cabbage leaf curl virus from Georgia. References: (1) A. M. Abouzid et al. Phytopathology 82:1070, 1992. (2) S. S. Pappu et al. Plant Dis. 84:370, 2000. (3) M. R. Rojas et al. Plant Dis. 77:340-347, 1993.

Hyperkalaemic quadriparesis secondary to chronic diclofenac treatment

A 76 year old woman presented with a quadriparesis associated with hyperkalaemia. She had a 10 month history of treatment with oral diclofenac sodium. On admission she had hyperkalaemic metabolic acidosis with a normal anion gap and mild renal impairment. Her weakness resolved after withdrawal of diclofenac and medical correction of her hyperkalaemia. Non-steroidal anti-inflammatory drugs are known to cause hyperkalaemic acidosis and should be used with caution, especially in the presence of renal impairment.

Catastrophic antiphospholipid syndrome presenting as dilated cardiomyopathy with bilateral branch retinal artery thrombosis

Cardiac manifestation of antiphospholipid syndrome (APS) is mainly in the form of left-sided valvular insufficiency, intra-cardiac thrombi or coronary artery occlusion. Dilated cardiomyopathy is a rare but important cardiac manifestation of APS, and responds well to adequate anticoagulation and steroids. We describe a case in which APS presented with dilated cardiomyopathy and bilateral retinal artery thrombosis.

Emerging Plasmodium falciparum in an endemic area in Calcutta

Calcutta is now intensely malarious. Malarial infections are detected in every month. In an endemic area in central Calcutta a year-long study from August 1996 to July 1997 reveals that 31.47% of all cases are due to Plasmodium falciparum infection. A competition is going on between P vivax and P falciparum to gain upperhand. An equilibrium is there in the month of January (1997), when P vivax and P falciparum cases constitute 51.13% and 49.43% respectively. The highest and lowest percentage of P falciparum infection is in December 1996 (67.98%) and in May 1997 (0.89%) which is just reverse in the case of P vivax in December 1996 (33.60%) and in May 1997 (99.10%). Three imported cases of P malariae have been detected but the patients cannot be traced. Six cases of mixed infections have been found.

Determination of manganese in environmental samples (e.g. coal fly ash) by electrothermal AAS after its separation with a liquid chelating ion exchanger

An electrothermal atomic absorption spectrometric method is described for the determination of manganese in various coal fly ash samples after its separation with dissolved monothioxo-beta-diketone as chelating ion exchanger. The detection limit is 1 ng ml(-1). To study the accuracy of the method, a reference material of similar composition was analysed and recovery of spiked manganese was performed.

A comparison of the clinico-pathological features with stool pathogens in patients hospitalised with the symptom of diarrhoea

The clinico-pathological features of 515 adult patients admitted to a major Regional Infectious Diseases Unit in United Kingdom with the symptom complex of diarrhoea were compared to the pathogens detected in their stool specimens. Routine clinical examination supported by basic pathological and laboratory investigations identified 138 (28%) in whom the cause of diarrhoea was extragastrointestinal or non-infectious gastrointestinal. Of the 351 patients (72%) with infectious gastroenteritis 72 (21%) had campylobacter, 59 (17%) had salmonella (22% bacteraemic) and 16 (5%) shigella. Clostridium difficile toxin accounted for a further 15 (4%)--antibiotics had been the antecedent cause in only one half of these. Routine microscopical examination of the faeces for red and white cells distinguished many with "culture positive" diarrhoea from those with "culture negative" infectious diarrhoea. Although there are no clinico-pathological features which are unique to a particular pathogen and unequivocally suggest a particular pathogen, certain features did tend to present more often in association with particular microorganisms, and this knowledge may suggest a bacterial diagnosis whilst awaiting the definitive results of stool microbiology. These features include prior antimicrobial therapy with positive sigmoidoscopical/histological features: Cl. difficile; protracted diarrhoea in elderly severely dehydrated patients: salmonellosis; foreign travel in males with bloody diarrhoea: shigellosis; abdominal pain in younger patients with a small degree of vomiting: campylobacteriosis. Early diagnosis may then prove useful in rationalizing initial therapy, particularly the appropriate use of antimicrobials.