Respiratory findings in art students

Art students are exposed to many noxious agents during their training. We studied respiratory findings in a cohort of the 117 art students in order to investigate the potential effects of these toxic agents in the art student's environment. A group of 88 medical students matched for age, sex and smoking, not exposed to known environmental pollutants were studied as controls for respiratory symptoms. Respiratory symptoms acute and chronic were evaluated by modifying the British Medical Research Council questionnaire. Lung function studies were performed with a spirometer (Jaeger, Germany) measuring maximum expiratory flow-volume (MEFV) curves. Significantly higher prevalences of most of the chronic respiratory symptoms were recorded in art compared to medical students (p < 0.05). Art students who were smokers had significantly higher prevalences of many of the chronic respiratory symptoms than nonsmoking art students. High prevalences of acute symptoms related to the study environment were recorded for art students. Odds ratios in male art students were significant for chronic cough, chronic phlegm and chronic bronchitis for the risk factors of exposure and smoking. Significantly decreased lung function was recorded for FVC, FEF50 and FEF25 in male and FVC, and FEF25 in female art students. Smokers and nonsmokers had similar reductions of lung function. Our data indicate that art students may be at risk of developing chronic respiratory symptoms and lung function changes as a result of their exposure and their smoking habits.     

Functional analysis of plasma prophenoloxidase system in the marine mussel Perna viridis

The role of prophenoloxidase (proPO) system in recognition and phagocytosis of yeast cells by hemocytes was examined in vitro using whole plasma and proPO system isolated from the plasma of the marine mussel, Perna viridis. The proPO was isolated from the plasma by ammonium sulphate precipitation and gel filtration. The final proPO preparation was homogeneous in native PAGE, and could be activated by trypsin, α-chymotrypsin and pronase-E. Laminarin (a polymer of β-1, 3-glucan) and lipopolysaccharides (LPS) from diverse bacterial species effectively activated the isolated proPO, demonstrating the ability of this proenzyme to interact directly with microbial surface components. The susceptibility of proPO activation to inhibition by serine protease inhibitors such as soybean trypsin inhibitor (STI) or p-nitrophenyl-p′-guanidinobenzoate (p-NPGB), indicates that the isolated fraction may contain an integral serine protease domain in an inactive state. The presence of laminarin- or LPS-activated whole plasma of P. viridis facilitated adherence of yeast cells to hemocyte surface as well as eventually stimulated phagocytic uptake of the target cells by hemocytes, and no such hemocytic response was recorded with STI controls. This and other results strongly suggest that the intermediary factors generated during activation of plasma proPO system by non-self molecules play a key role in recognition and opsono-phagocytosis by hemocytes. However, the proPO system isolated from P. viridis plasma, after activation with microbial surface components, failed to show an opsonic effect.     

γ–aminobutyric acid promotes stem elongation in Stellaria longipes: The role of ethylene

The response of stems to GABA was biphasic in that lower concentrations of GABA (upto 500 µM) promoted stem elongation, but higher concentrations of GABA inhibited stem elongation. An optimal GABA concentration of 250 µM produced maximum stem elongation. The higher GABA concentrations also stimulated 1-aminocyclopropane-1-carboxylate (ACC) synthase (EC 4.4.1.14) mRNA accumulation and ethylene production. Results suggest that the inhibitory effect of higher GABA concentrations on stem elongation is partly mediated by ethylene.     

Synthesis of hexaploid (AABBCC) somatic hybrids: a bridging material for transfer of ‘tour’ cytoplasmic male sterility to different Brassica species

Most of the alloplasmic cytoplasmic male sterility (CMS) systems are known to be associated with a number of floral abnormalities that result from nuclear-cytoplasmic incompatibilities. One such system, tour, which is derived from Brassica tournefortii, induces additional floral abnormalities and causes chlorosis in Brassica spp. While the restorer for this CMS has been reported to be present in B. napus, in B. juncea, where the abnormalities are more pronounced, no restorer has yet been identified. Rectification of these floral abnormalities through mitochondrial recombinations and chloroplast replacement might result in the improvement of this CMS system. As organelle recombinations can possibly be achieved only by somatic cell hybridization, fusion experiments were carried out between hygromycin-resistant B. juncea AABB carrying tour cytoplasm and phosphinotricin-resistant, normal B. oleracea CC to generate AABBCC hexaploid somatic hybrids. The presence of selectable marker genes facilitated the selection of hybrids in large numbers. The resulting hybrids showed wide variation in floral morphology and organelle composition. Regenerants with normal, male-sterile flowers having recombinant tour-or oleracea-type mitochondria and oleracea-type chloroplasts were obtained. Hybrids with male-fertile flowers were also obtained that had recombined tour mitochondria. The AABBCC hexaploid hybrids synthesized in the present study were successfully utilized as a bridging material for transferring variability in the organelle genome simultaneously to all the digenomic Brassica species, and all of these hybrids are now being stabilized through repeated backcrosses to the allopolyploid crop brassicas.     

Transfer of Brassica tournefartii (TT) genes to allotetraploid oilseed Brassica species (B. juncea AABB, B. napus AACC, B. carinata BBCC): homoeologous pairing is more pronounced in the three-genome hybrids (TACC, TBAA, TCAA, TCBB) as compared to allodiploids (TA, TB, TC)

For the transfer of genes from B. tournefortii (TT) to the allotetraploid oilseed brassicas, B. juncea AABB, B. carinata BBCC and B. napus AACC, B. tournefortii was first crossed with the three basic diploid species, B. campestris (AA), B. nigra (BE) and B. oleracea (CC), to produce the allodiploids TA, TB and TC. These were tetraploidized by colchicine treatment to produce the allotetraploids TTAA, TTBB and TTCC, which were further crossed with B. juncea and B. napus to produce three-genome hybrids with substitution-type genomic configurations: TACC, TBAA and TCAA. These hybrids along with another hybrid TCBB produced earlier, the three allodiploids, their allotetraploids and the four diploid parent species were studied for their male meiotic behaviour. The diploid parent and the allotetraploids (TTAA, TTBB and TTCC) showed regular meiosis although the pollen viability was generally low in the allotetraploids. In the allodiploids (TA, TB and TC) only some end-to-end associations were observed without any clearly discernible chiasmata or exchange points. Chromosomes involved in end-to-end associations were randomly distributed at the metaphase/anaphase-I stages. In contrast, the three-genome hybrids (TACC, TBAA, TCAA and TCBB) showed normal bivalents whose number exceeded the expected bivalent values. Bivalents arising out of homoeologous pairing were indistinguishable from normal pairs by their disjunction pattern but could be distinguished on the basis of the heteromorphy of the homoeologous chromosomes. The three-genome hybrids could be backcrossed to allotetraploid oilseed brassicas as they had some fertility. In contrast, the allodiploids could neither be selfed nor back-crossed. On the basis of their meiotic stability, in terms of more pronounced homoeologous pairing and fertility for backcrossing, the three-genome configurations provide the best possible situation for the introgression of alien genes from the secondary gene pool to the allotetraploid oilseed crops B. juncea, B. napus and B. carinata.     

Nature and distribution of copper in green lagoon crab Scylla serrata (Forskal)

In Scylla serrata (Forskal), copper is present in detectable quantities in all tissues except the central nervous system. 75% of animal's total copper is found in the haemolymph, hepatopancreas, and cuticle. Both the haemolymph and the hepatopancreas share equally ≈ 60% of the animal's total copper. Copper is found in the TCA-soluble and insoluble fractions of water-soluble tissue extracts and in the chloroform : methanol-soluble and insoluble fractions of water-insoluble residue from the hepatopancreas. No other tissue has all the fractions of copper. In haemolymph copper is present only in the TCA-insoluble fraction. The TCA-soluble fraction is also absent in muscles. The absence of any lipid-bound copper in other tissues and the presence of copper in all fractions from the hepatopancreas indicates that this tissue may play a major role in the mobilization, conservation and detoxication of copper.     

Effect of differential housing in mice on natural killer cell activity, tumor growth, and plasma corticosterone.

Various forms of stress have been shown to alter natural killer (NK) cell activity and tumorigenesis; however, few studies have measured these two variables simultaneously. Isolation of mice was utilized as a model of stress by which to study NK cell activity and pulmonary metastatic response following a tumor challenge. Male C3H mice were group or individually housed for 3 weeks, after which CIRAS 3 fibrosarcoma tumor cells or the tumor vehicle was injected intravenously (tail vein), NK cell activity, pulmonary metastasis, and plasma corticosterone were measured 1, 7, and 21 days following tumor cell inoculation. Individually housed mice, irrespective of tumor or vehicle condition, had a higher NK response on Day 1 relative to group-housed animals (P less than 0.001). By Day 21, tumor condition, rather than housing, was the major significant factor affecting NK activity (P less than 0.001). Nevertheless, individually housed, tumor-injected mice still had higher NK activity compared with the other treatment groups on Day 21. No effect of housing condition was present for the incidence of pulmonary metastases or frequency of metastases in affected animals. Plasma corticosterone levels generally increased over the study period, with no housing or injection effects at Days 1 and 7. Individually housed, vehicle-injected mice had higher corticosterone levels at Day 21 (P less than 0.01). These data suggest that in response to housing condition, NK cell activity differs in tumor-bearing mice and vehicle controls. Furthermore, CIRAS 3 pulmonary tumor formation is not affected by differences in NK activity consequent to housing condition. Plasma corticosterone does not appear to be a major in vivo regulator of NK activity in this experimental tumor system. Finally, the interpretation of housing effects on NK activity and plasma corticosterone levels depends on the temporal window in which sampling occurs.     

Growth Stimulation by Conditioned Medium and Spermidine in Low-Density Suspension Cultures of Rice

Suspension cultures of Oryza sativa L. var IR 20 grew in Murashigeand Skoog medium (MS) supplemented with 2,4-D and kinetin ina density-dependant manner with a critical minimum inoculation-densityof 10,000 cells ml^–1. Conditioned medium obtained fromthese cultures and added to MS+2,4-D+kinetin induced the growthof cultures at 1,000 cells ml^–1. Growth stimulation byconditioned medium was mimicked by spermidine but not by otherpolyamines viz. putrescine and spermine. This is the first reportof a polyamine substituting for conditioned medium in cultures. ² Present address: Vice-Chancellor, Pondicherry University,Pondicherry 605 014, India.