Quality of paper boards from arecanut leaf sheath

A study was carried on utilizing arecanut leaf sheath for making paper boards. Paper boards were made with various combinations of arecanut leaf sheath with waste paper, 1:1, 1:2, 1:3, 3:1, 2:1, control (100% areca leaf sheath) and the qualities of these paper boards were tested as per the Bureau of Indian Standards (IS: 1060 (part-I)-1966). The paper boards made with more arecanut sheath materials had more resistance to water absorption. The addition of paper increased the substance weight of the paper boards. The 2:1 and 3:1 combinations of arecanut leaf sheath and waste paper had best tear strength, tensile strength, bursting strength and water resistance with minimum substance weight.

Immunology of the pathogen virulence and phytotoxin production in relation to disease severity: a case study in sheath blight of rice

Polyclonal antibodies against purified Rhizoctonia solani toxin obtained from infected rice sheath tissues (sheath blight toxin, SBT) and culture filtrates (culture filtrate toxin, CFT) were developed in rabbit and chicken. The IgG was isolated from serum and egg yolk of rabbit and chicken, respectively, and their specificity was investigated by indirect ELISA. Antibodies developed against CFT and SBT in rabbits exhibited relatively higher titer values when compared to chicken antibodies. Positive correlation was observed between the degree of sheath blighting and the levels of antigens induced by each isolate during sheath blight symptom development as detected by rabbit SBT antibody and the isolate RS7 was identified as most virulent. Optimization of incubation period for maximum toxin production in liquid medium and rice sheaths indicated that the production of CFT and SBT is maximum after 15 d and 6 d of pathogen inoculation. Studies of the possible translocation of RS-toxin in rice plants upon inoculation with R. solani showed downward translocation as detected by rabbit/chicken SBT antibodies. Since plant inoculation required a higher concentration of inoculum and maintenance of plants, serological assay by ELISA is more sensitive than whole-plant assays in detecting RS-toxin, with the advantage that ELISA also allows rapid determination of RS-toxin production.

Nonconventional carbon additions to azomethines. aryl amination/indoline synthesis by direct aryl radical addition to azomethine nitrogen

[reaction: see text]. The generality of a new method for aryl amination has been defined. Ketimines derived from o-bromophenethylamine cyclize to the N-substituted indoline when treated with nBu3SnH and a radical initiator. The pH-neutral conditions tolerate base- and acid-sensitive functionality. The observed regioselectivity is nonconventional for addition reactions involving carbon radicals and carbon-heteroatom pi-bonds.

Antifungal activity of chitinases produced by some fluorescent pseudomonads against Colletotrichum falcatum Went causing red rot disease in sugarcane

Chitinase production and growth of certain fluorescent pseudomonads isolated from sugarcane rhizosphere on different subtrates were studied. When chitin was substituted for glycerol in King's B medium, 3 of the 4 strains showed enhanced bacterial multiplication. Bacterial cells grown on chitin-containing medium showed enhanced antifungal activity against Colletotrichum falcatum Went causing red rot disease in sugarcane. Chitinase production was significantly higher when chitin was amended to King's B medium. Higher chitinase production was also recorded when fluorescent pseudomonad strains were grown in the medium containing crab-shell chitin. Cell-free bacterial culture filtrate from chitin-containing medium significantly inhibited mycelial growth of the pathogen. These cell-free conditioned media contained 3 to 7 polypeptides. Western blot analysis revealed five isoforms of chitinase with molecular masses of 47, 36, 32, 20 and 18.5 kDa. A possible role of chitinases in red rot disease management is discussed.

Oral lesions and conditions associated with human immunodeficiency virus infection in 300 south Indian patients

BACKGROUND

Human immunodeficiency virus infection/acquired immunodeficiency syndrome (HIV/AIDS) is a major health problem in India. The National AIDS Control Organisation (NACO) of India reports a seropositivity of 25.03 per thousand for the whole country, as of October 1999. In spite of this high prevalence there are very few reports of oral lesions and conditions in Indian HIV/AIDS patients, which are important in early diagnosis and management of these patients.

OBJECTIVE AND SETTING

The present report describes the oral lesions in 300 HIV positive symptomatic patients presenting to us at RAGAS-YRG CARE, a non-governmental organisation in Chennai, South India, over a period of 9 months in 1998.

METHOD

Lesions were diagnosed on clinical appearance using international criteria.

RESULTS

Of the 300 patients 89% had acquired the infection through heterosexual contact. There were 205 males and 95 females, aged from 7 months to 72 years. Forty-seven percent of the patients were in the age group 21-30 years. CD4 counts were ascertained for 105 patients, 64 (62%) had CD4 counts < or = 200. A total of 217 (72%) of the 300 patients had some oral lesion when examined. Gingivitis (47%) and pseudomembranous candidiasis (33%) were the most common oral lesions. The other oral lesions seen were oral mucosal pigmentation (23%), erythematous candidiasis (14%), periodontitis (9%), angular cheilitis (8%), oral ulcers (3%), oral hairy leukoplakia (3%), hyperplastic candidiasis (1%), oral submucous fibrosis (2%) and one case of leukoplakia.

CONCLUSIONS

Oral lesions occur commonly in HIV infection. A comprehensive oral examination may not only suggest HIV disease but may also be useful in monitoring the disease progression. This is a cost-effective procedure, which may be useful in screening large populations in developing countries like India.

Proteinmorphosis: a mechanical model for protein conformational changes

Proteinmorphosis is a physically-based interactive modeling system for simulating large or small conformational changes of proteins and protein complexes. It takes advantage of the cross-linked one-dimensional nature of protein chains. The user can, based on her chemical knowledge, pull pairs of points (lying either on a single protein or on different molecules) together by specifying geometric distance constraints. The resulting conformation(s) of the molecule(s) of interest is computed by an efficient finite element formalism taking into account elasticity of the protein backbone, van der Waals repulsions, hydrogen bonds, salt bridges and the imposed distance constraints. The conformational change is computed incrementally and the result can be visualized as an animation; complete interactivity is provided to position and view the proteins as desired by the user. Physical properties of regions on the protein can also be chosen interactively. The conformational change of calmodulin upon peptide binding is examined as a first experiment. It is found that the result is satisfactory in reproducing the conformational change that follows on peptide binding. We use Proteinmorphosis to study the cooperative hemoglobin oxygen binding mechanism in a second, more sophisticated, experiment. Different modeling strategies are designed to understand the allosteric (cooperative) binding process in this system and the results are found to be consistent with existing hypotheses.

Streptococcal emm types associated with T-agglutination types and the use of conserved emm gene restriction fragment patterns for subtyping group A streptococci

The T-agglutination types were determined for a diverse collection of 1531 group A streptococci for which the 5' M protein gene (emm) sequences had been analysed. The majority of the T-agglutination types correlated with previously seen M/emm/T-type associations; however, several new associations were found. Analysis of a subset of this collection -- which included 1157 clinical isolates with multiply encountered emm types -- found that emm amplicon restriction profiles of isolates sharing identical T types and opacity factor phenotypes are useful for detecting groups of isolates with identical emm genes. Many emm genes of known 5' sequence display a highly conserved restriction pattern amongst clinical isolates widely separated both geographically and temporally.

Combinatorial electrochemistry: A highly parallel, optical screening method for discovery of better electrocatalysts

Combinatorial screening of electrochemical catalysts by current-voltage methods can be unwieldy for large sample sizes. By converting the ions generated in an electrochemical half-cell reaction to a fluorescence signal, the most active compositions in a large electrode array have been identified. A fluorescent acid-base indicator was used to image high concentrations of hydrogen ions, which were generated in the electrooxidation of methanol. A 645-member electrode array containing five elements (platinum, ruthenium, osmium, iridium, and rhodium), 80 binary, 280 ternary, and 280 quaternary combinations was screened to identify the most active regions of phase space. Subsequent "zoom" screens pinpointed several very active compositions, some in ternary and quaternary regions that were bounded by rather inactive binaries. The best catalyst, platinum(44)/ruthenium(41)/osmium(10)/iridium(5) (numbers in parentheses are atomic percent), was significantly more active than platinum(50)/ruthenium(50) in a direct methanol fuel cell operating at 60 degreesC, even though the latter catalyst had about twice the surface area of the former.

Lymphoma of the lumbar nerve root: case report

BACKGROUND AND IMPORTANCE

Lymphoma deposits in the spine are typically extradural. However, we report the case of a 38-year-old man who had a peripheral T-cell lymphoma with both intra- and extradural involvement.

CLINICAL PRESENTATION

The patient presented with a 3-month history of right hip and thigh pain. Computed tomography and magnetic resonance imaging revealed features indistinguishable from those of a benign neurofibroma, except for a small area of T2-weighted signal abnormality in the third lumbar vertebral body.

INTERVENTION

A solitary lesion of the right third lumbar root with normal surrounding bone and soft tissue was excised at surgery. At immunohistopathological evaluation, a diagnosis was made of peripheral lymphoma. Postoperative evaluation did not reveal lymphoma in the cerebrospinal fluid, abdomen, chest, blood, or bone marrow. This case illustrates that lymphomas can grow in patterns indistinguishable from a tumor of a nerve root. Therefore, other treatment modalities would have been considered had the diagnosis of lymphoma been made preoperatively.

CONCLUSION

Involvement of a solitary nerve root by lymphoma, although rare, should be suspected in all cases of nerve root neurofibroma, and magnetic resonance imaging should be performed. Even minor signal abnormalities in adjoining vertebrae signal the possibility of malignancy. Percutaneous biopsy of suspicious bony lesions and systemic evaluation can demonstrate other sites of involvement, enabling the confirmation of the diagnosis and appropriate treatment without recourse to surgery.

Physiological basis in the assessment of ecotoxicity of pesticides to soil organisms

Earthworms are universally accepted as one of the most suitable and representative soil animals to be used for assessing chemical pollution in soils. Therefore, in this work earthworm species diverse in habitat and life-pattern are used and the effects of sublethal concentrations of terbuthylazine and carbofuran on the reproductive processes, respiration and excretion are investigated. The results show that even low and moderate concentrations of the pesticides can induce measurable physiological effects. Species-specific and substance-specific effects are noticeable in the worms.