Aspiration vs nonaspiration technique of cytodiagnosis--a critical evaluation in 160 cases

The two sampling techniques were studied in 160 randomly selected cases of superficial swellings in various sites of the body. They were sampled by fine needle aspiration (FNA) and by non-aspiration (NA) (a needle without application of aspiration pressure). Cell samples were cytologically assessed and critically evaluated using five objective parameters. Contamination with blood was more in lymphnode, thyroid and liver lesions in aspiration smears than NA smears and values were statistically significant. Similarly when compared for the degree of cellular trauma and cellular degeneration statistically significant better results were obtained by nonaspiration technique for lymphnode lesions. Regarding amount of cellular material obtained by FNA, statistical significant better results were found for breast lesions only. Statistically significant better maintenance of architecture was observed only for thyroid lesions by NA technique. Better average scores were observed by NA technique for lymphnode and thyroid only. Categorizing all the smears obtained by FNA & NA on the basis of their scores according to predetermined criteria, greater number of diagnostically adequate specimens were obtained by FNA than by NA but the number of diagnostically superior specimens obtained by NA technique was found to be more than that by FNA. The difference was found to be statistically significant. However the number of inadequate smears was also more by NA technique than by FNA technique.

Common nitrogen control of caesium uptake, caesium toxicity and ammonium (methylammonium) uptake in the cyanobacterium Nostoc muscorum

Studies were carried out to examine the role of ammonium transport activity in the control of caesium uptake and toxicity in Nostoc muscorum. The results showed a definite specific role of the ammonium-repressible/derepressible ammonium transport system of the cyanobacterium in caesium uptake, accumulation and toxicity. Furthermore, the results showed that N. muscorum can acquire resistance against diazotrophically-associated caesium toxicity when supplied with ammonium as a nitrogen source. In addition, alternatively, a mutant strain was Cs-resistant in the absence of any effect on NH(+4)-transport, suggesting that Cs+ resistance may be determined at more than one cellular site.

Mutational analysis of the NH4+-nitrogen controls that regulate ammonium transport activity, heterocyst differentiation, nitrogenase activity and the heterocyst-spacing pattern in the cyanobacterium Nostoc muscorum

Mutational analysis of the genetic determinants mediating NH(4+)-nitrogen regulating effects on NH(4+)-transport activity, heterocyst differentiation, nitrogenase activity and heterocyst pattern formation was carried out in Nostoc muscorum. Evidence suggested the operation of three separate genetic determinants in such nitrogen control; one mediating NH(4+)-repression control on both heterocyst formation and NH(4+)-transport activity, a second (Nif-R) mediating NH(4+)-repression control on nitrogenase synthesis/activity and a third (Pat-R) essential for intercalary heterocyst formation/distribution. Ammonia itself functioned as repressor signal of heterocyst formation and nitrogenase synthesis/activity and the glutamine synthetase enzyme played no role in the repression/derepression control of heterocyst development and functional nitrogenase formation.

Mutational replacement of molybdenum by vanadium in assimilation of N2 or NO3- as nitrogen source in the cyanobacterium Nostoc muscorum

Tungsten resistant (Wr) mutants of Het+Nif+Nia+, Het+Nif-Nia+ and Het+Nif+Nia- strains of Nostoc muscorum were isolated with severely defective molybdate transport activity. All such mutants showed vanadium (V)-dependent nitrogenase activity and/or nitrate reductase activity and V-dependent growth on N2-nitrogen and/or NO3(-)-nitrogen and V-dependent NO3(-)-repression of heterocyst formation and nitrogenase activity. None of them grew with molybdenum (Mo) under parallel growth condition. Results strongly suggest the ability of V to replace Mo in N2-assimilation or NO3(-)-assimilation under Mo-deficiency.

Dopaminergic regulation of luteinizing hormone-releasing hormone release at the median eminence level: immunocytochemical and physiological evidence in hens

Theoretically, the most effective inhibitory control of hypophysiotropic luteinizing hormone-releasing hormone (LHRH) release might occur through a presynaptic inhibition of LHRH neuronal terminals at the median eminence (ME) level. Since: (a) we have recently reported the existence of synaptic contacts between dopamine- and LHRH-containing processes in the ewe ME, and (b) nutritional deprivation induces an ovulatory failure in both birds and mammals, we have assessed the possibility that the anovulatory state induced by feed withdrawal (FW) in laying hens, might be caused by a dopaminergic inhibition of LHRH release at the ME level. Laying hens at the start (35 weeks old) and end (75 weeks old) of their commercial egg-laying life were killed at 0, 1, 2 and 4 days after FW. Serum luteinizing hormone (LH) and progesterone (P4), in vitro release of LHRH by isolated ME, and LHRH content in ME and preoptic area (POA) were determined by RIA. ME content of dopamine (DA) and its main metabolite 3,4-dihydroxyphenylacetic acid (DOPAC) were assessed by LCED. The distribution of LHRH and tyrosine hydroxylase (TH)-containing processes at the ME level of the hen was determined immunocytochemically. In the hen, LHRH-containing cell bodies are localized in the anterior hypothalamus and medial POA. LHRH-containing axons project toward the ME and infundibulum through the ventral-lateral hypothalamus. TH-containing perikarya are concentrated in the arcuate nucleus and in the adjacent part of the periventricular nucleus, dorsal to the arcuate. TH-containing axons converge toward the ME and descend into the infundibulum. Dense concentrations of TH- and LHRH-containing processes are located in the lateral and mediobasal portions of the external layer of the ME, providing opportunities for synaptic interactions between them. Ovulatory failure and regression of the ovary and reproductive tract occurred 2-3 days after FW at the end, but not at the beginning of the hen's commercial egg-laying life. After FW, hens at the end of their productive life had higher (p less than 0.01) tuberoinfundibular DA turnover, produced less LHRH, and had lower serum LH and P4 than hens undergoing FW at the beginning of their productive life. In addition, in vitro release of HRH from denervated ME tissue of hens undergoing FW at the end of their commercial egg-laying life was higher and was reversed in a dose-dependent fashion by DA, but not by serotonin. Thus, the ovulatory failure associated with FW in laying hens might be caused by a presynaptic inhibition of in vivo LHRH release at the level of ME hypothalamic neuronal terminals.

Evidence for a role of glutamine synthetase in assimilation of amino acids as nitrogen source in the cyanobacterium Nostoc muscorum

Methylammonium/ammonium ion, glutamine, glutamate, arginine and proline uptake, and their assimilation as nitrogen sources, was studied in Nostoc muscorum and its glutamine synthetase-deficient mutant. Glutamine served as nitrogen source independent of glutamine synthetase activity. Glutamate was not metabolised as a nitrogen source but still inhibited nitrogenase activity and diazotrophic growth. Glutamine synthetase activity was essential for the assimilation of N2, ammonia, arginine and proline as nitrogen sources but not for the control of their transport, heterocyst formation, and production of ammonia or aminoacid dependent repressor signal for N2-fixing heterocysts. These results also suggest that glutamine synthetase serves as the sole route of ammonia assimilation and glutamine synthesis, and ammonia per se as the repressor signal for N2-fixing heterocysts and methylammonium (ammonium) transport.

Evidence for energy-dependent copper efflux as a mechanism of Cu2+ resistance in the cyanobacterium Nostoc calcicola

Wild-type Nostoc calcicola carried out oxygenic photosynthesis extremely sensitive to copper. A Cu(2+)-resistant mutant (Cu-R1) of the cyanobacterium grew normally at high concentrations of Cu2+. Its ability to grow under such conditions was found to be due to mutational acquisition of an energy-dependent efficient system of Cu(2+)-efflux, which rendered Cu(2+)-inhibited oxygenic photosynthesis fully reversible.

Relationship of blood markers to disease severity and drug efficacy in rat adjuvant arthritis

Rat adjuvant arthritis (AA) was used as a model to evaluate several blood markers as possible predictive indicators of drug efficacy. AA was induced in Sprague-Dawley rats by the injection of complete Freund's adjuvant into the right hind foot pad. The rats were dosed p.o. from day 18 to day 31 with levamisole (10 mg/kg), indomethacin (1 mg/kg), diclofenac sodium (0.5 & 1 mg/kg), and prinomide (10 & 20 mg/kg). Disease severity was assessed by paw circumference on day 31. The following blood markers were analyzed: hyaluronate by ELISA, prostaglandin E2 by RIA, ESR by micro-dispette, total PMN by Technicon H-1, and albumin by BCG dye. Blood marker correlation (r) to disease severity was: hyaluronate (0.71), prostaglandin E2 (0.58), ESR (0.52), PMN (0.58), and albumin (-0.71). The relative rank order of drug efficacy (indomethacin, diclofenac sodium, and prinomide) did not differ using the change in paw circumference (day 31-day 17) or blood markers. Levamisole exacerbated the disease as measured by all the above parameters. Thus, these blood markers provide additional information for the statistical evaluation of drugs in rat adjuvant arthritis.

Pharmacological modulation of rat monocytes: in vivo effects on Ia expression and interleukin-1 production

We have shown that during the developing phase of adjuvant disease (AD) in rats the expression of MHC class II (Ia) antigens on blood monocytes (BM) was enhanced. The results of a study in established AD are reported now. Four agents were tested: indomethacin and diclofenac-sodium (1 mg/kg/day); levamisole and prinomide (10 mg/kg/day), administered orally from day 18-31 after induction of AD. We assessed the following BM parameters: Ia expression, interleukin-1 (sIL-1) production, and membrane bound IL-1 (mIL-1). In AD Ia expression was enhanced, no changes occurred in mIL-1 or sIL-1. Indomethacin treatment reduced sIL-1 production, levamisole Ia expression and mIL-1 activity, prinomide all three parameters measured and diclofenac, though clinically effective, none.

Influence of different forms of nitrogen on uptake of ammonium, glutamate and glutamine in the cyanobacterium Nostoc muscorum

Effect of various types of nitrogen nutrition was studied on the uptake of ammonium, glutamate and glutamine by Nostoc muscorum and its Het-Nif- mutant. Ammonium nitrogen acted as a potent inhibitor/repressor of ammonium, glutamate and glutamine transport. Nitrate nitrogen was found to be a strong inhibitor/repressor of ammonium transport, a partial inhibitor/repressor of glutamate transport but, caused a partial stimulation of glutamine transport.

Genetic transformation of glutamine auxotrophy to prototrophy in the cyanobacterium Nostoc muscorum

Glutamine auxotrophic (Gln-) and L-methionine D,L-sulfoximine (MSX) resistant (MSXr) mutants of N. muscorum were isolated and characterized for nitrogen nutrition, nitrogenase activity, glutamine synthetase (GS) activity and glutamine amide, alpha-keto-glutarate amido transferase (GOGAT) activity. The glutamine auxotroph was found to the GOGAT-containing GS-defective, incapable of growth with N2 or NH4+ but capable of growth with glutamine as nitrogen source, thus, suggesting GS to be the primary enzyme of both ammonia assimilation and glutamine formation in the cyanobacterium. The results of transformation and reversion studies suggests that glutamine auxotrophy is the result of a mutation in the gln A gene and that gln A gene can be transferred from one strain to another by transformation.

EVIDENCE FOR INTERGENERIC TRANSFORMATION IN FILAMENTOUS, DIAZOTROPHIC CYANOBACTERIA

A clonal population of a mutant Nostoc muscorum, with the ability to assimilate azide as a fixed nitrogen source, was used as a source of donor DNA for transforming Anabaena doliolum from an azide-sensitive to an azide-assimilating phenotype. The donor DNA. transformed A. doliolum efficiently and the transformation process was sensitive to DNAase, resistant to RNAase A, dependent on photosynthetic light and required a specific contact period between donor DNA and recipient cells. The gene(s) responsible for azide assimilation appear to be located on chromosomal DNA and not on plasmid DNA. The transformants of A. doliolum resemble the azide assimilating mutant strain of N. muscorum in respect of (1) azide repression of heterocyst and nitrogenase formation, (2) azide-dependent increase in phycocyanin to chlorophyll ratio. These results suggest that the chromosomal DNA of mutant N. muscorum, and not its plasmid DNA, is the carrier of genetic information for its azide assimilatory phenotype and that this can be transferred efficiently to A. doliolum.

CARBON NUTRITION AND THE REGULATION OF UPTAKE HYDROGENASE ACTIVITY IN FREE-LIVING AND SYMBIOTIC ANABAENA CYCADEAE

Anabaena cycadeae was grown with N₂ as nitrogen source, either photoautotrophically in light or with glucose as carbon source in darkness. The rate of growth was much slower in darkness but the heterocyst frequency was much the same; nitrogenase activity (on a chlorophyll basis) was about half that of light-grown cells. Light-grown organisms contained uptake hydrogenase activity but dark-grown organisms did not. The addition of glucose to light-grown organisms was followed by the disappearance of uptake hydrogenase activity over the following 48 hours and the disappearance was independent of light. Heterocyst frequency and nitrogenase activity were much less affected by glucose addition. A. cycadeae growing symbiotically in cycad roots had much higher heterocyst frequency and nitrogenase activity than the free-living form but no detectable uptake hydrogenase activity. It is suggested that the rate of supply of carbohydrate to the heterocyst controls the development of uptake hydrogenase activity and that the absence of this activity in the symbiotic cyanobacteria indicates that the organisms in the cycad roots have an ample supply of carbohydrate.

REGULATION BY AZIDE OF HETEROCYST AND NITROGENASE IN AZIDE-RESISTANT MUTANTS OF THE CYANOBACTERIUM, NOSTOC MUSCORUM

A novel class of azide-resistant mutants of N, muscorum is described in which azide caused inhibition of heterocyst differentiation and nitrogen fixation without causing inhibition of growth. The results indicate the utilization of azide, as a fixed nitrogen source, by the mutant strain. An increase in the ability to take up azide and in the phycocyanin/chlorophyll ratio following growth of the mutant in azide-containing medium are additional findings which support the conclusion that the mutant utilizes azide as a source of nitrogen. In the parental strain, Ca²⁺ -dependent and Mg²⁺ -dependent ATPases, and cellular nitrate reductase were inhibited by azide. The corresponding ATPases from the mutant strain were not inhibited by azide. There was evidence, in cell-free extracts, for an enzyme system which utilized azide as an electron acceptor and NADPH-ferredoxin as electron donor. The activity of this system was significantly higher (on a protein basis) in cells of the mutant grown on azide than in cells of either the parent or the mutant when grown on nitrate. It is suggested that the azide resistance of this class of mutant is due to a mutation which leads to azide resistant Ca²⁺ - and Mg²⁺ - ATPases. Such a mutation may allow an azide utilizing system, inherently present in both parent and mutant strains, to be expressed.

Loss of aerobic nitrogen fixation associated with kasugamycin resistance in the heterocystous nitrogen-fixing, streptomycin resistant blue-green alga Nostoc muscorum

Heterocystous N2-fixing, Streptomycin resistant (Het (+)Nif(+)Str-R) Nostoc muscorum produces two groups of Kasugamycin resistant (Kas-R) phenotypes: one group showing normal heterocyst frequency and normal aerobic growth with N2 as a nitrogen source, the other group showing loss of growth with N2 as nitrogen source under aerobic growth conditions. Examination of strains showing Kas-R associated loss of aerobic N2 growth shows them to comprise three classes: Class A showing loss of both heterocyst and nitrogenase activity, class B showing formation of heterocyst but no nitrogenase activity and class C lacking heterocyst but containing microaerobic nitrogenase activity. The three classes of mutants revert to aerobic prototrophy with almost similar frequency of about 10(-6) suggesting them to have arisen as a result of single mutational events. Their reversion to prototrophy is simultaneously accompanied by the loss of Kas-R phenotype. All the phenotypic revertants in general appear more or less similar to the parental strain in respect to heterocyst formation, aerobic N2 growth and Kasugamycin sensitivity (Kas-S).

Evidence for ammonia as an inhibitor of heterocyst and nitrogenase formation in the cyanobacterium Anabaena cycadeae

Growth and regulation of heterocyst and nitrogenase by fixed nitrogen sources were studied comparatively in parent and glutamine auxotrophic mutant of Anabaena cycadeae. The parent strain grew well on N2, NH+4 or glutamine while the mutant strain grew on glutamine but not on N2 or NH+4. The total lack of active glutamine synthetase in the mutant strain thus appears to be the reason for its observed lack of growth in N2 or NH+4, which explains why it is a glutamine auxotroph and at the same time shows glutamine synthetase to be the sole primary ammonia assimilating enzyme. NH+4 repression of heterocyst and nitrogenase in the mutant and the parental strains and their derepression by L-methionine-DL-sulfoximine suggest that NH+4 per se and not glutamine synthetase mediated pathway of ammonia assimilation is the initial repressor signal of heterocyst and nitrogenase in A. cycadeae.

Inhibition of photosystem II of nitrogen-fixing blue-green alga Nostoc linckia by the rice-field herbicide benthiocarb

Effects of rice-field herbicide benthiocarb (S(4-chlorobenzyl)-N,N-diethyl thiolcarbamate) was studied on the nitrogen-fixing blue-green alga Nostoc linckia. The herbicide caused inhibition of growth and heterocyst formation, an increase in intensity of photoacoustic signals, and a four-fold reduction in oxygen evolution, but did not affect dark O2-uptake. The inhibition of growth and heterocyst formation was relieved by 500 micrograms/ml glucose. A Het-Nif- mutant of Nostoc muscorum failed to show an increase in reversion, frequency after treatment with 10 micrograms/ml benthiocarb for 1 hr.

Studies on Claviceps parasitic on Panicum species in India

Panicum repens and P. antidotale were found to be infected with Claviceps sp. This is the first report of ergot on P. repens. The pyrenomycete produced abundant sclerotia on the host plants. The sclerotia contained 0.71 and 0.68% alkaloids, respectively, which predominantly consisted of chanoclavine, festuclavine and agroclavine. The infected grasses were possibly mycotoxic. Submerged cultures of Claviceps strain isolated from Panicum spp. produced significant amount of chanoclavine, festuclavine and agroclavine. No pharmaceutically important alkaloid was found in sclerotia or in submerged culture.