Alterations inRhizobium trifolii catalase under water stress

Water stress resulted in a several-fold increase in the activity of catalase inRhizobium trifolii. Thermostability, pH and temperature profiles of the enzyme were altered by water stress.     

Transpiration in seven plant species colonizing a fishpond shore

In 7 species (Eleocharis palustris R. Br.,Juncus bufonius L.,Gypsophila muralis L.,Trifolium repens L.,Agrostis stolonifera L.,Potentilla anserina L. andAchillea millefolium L.) growing in a gradient of habitats from aquatic to terrestrial, on a sandy fishpond shore in Southern Bohemia, Czechoslovakia, the daily course of transpiration rate and water content was assessed gravimetrically in their cut-off transpiring parts on two typical summer days. Transpiration rate was largely controlled by microclimate but depressions occurred inJuncus and in some species growing in the drier habitats. The highest instantaneous transpiration rate and total daily transpiration per unit dry weight, about 100 mg g^?1 min^?1 and 50 g g^?1 d^?1, respectively, were recorded inAchillea andTrifolium. The water turnover rate ranged from 16.1 g g^?1 (H₂O) d^?1 inJuncus to 10.7 inGypsophila. The estimated daily maximum water saturation deficit was highest inEleocharis (45.7%) and lowest inAchillea (15.0%). The adaptational significance of the observed phenomena is discussed.     

Regulation of biosynthesis of secondary metabolites

Partially purified citrate synthase (EC 4.1.3.7) was isolated from submerged mycelium ofStreptomyces aureofaciens RIA 57, a strain producing chlortetracycline. Enzymatic activity was determined spectrophotometrically by means of 5,5′-dithio-bis-(2-nitrobenzoic acid). Citrate synthase was inhibited by ATP, inhibition being competitive with respect to acetyl coenzyme A. In 5mm concentration, ATP caused 55% inhibition of the enzyme. ADP, in the same concentration, caused 30% inhibition, while AMP caused none. Other natural nucleoside di- and triphosphates, in 1–5mm concentration, did not significantly affect citrate synthase inStreptomyces aureofaciens. Mg²⁺ inhibited the activity of the enzyme, but also reduced the negative effect of ATP. The role of ATP in regulation of the metabolic paths of acetyl CoA is discussed.     

The antibody response during amphibian ontogeny

The maturation of the anti DNP-response in adult and larval amphibians has been compared in two species of anurans,Rana catesbeiana andXenopus laevis. IgM responses were very similar in larvae and adults of both species. Specific IgG antibody synthesis, studied inRana catesbeiana only, was not obvious in larval primary response but was easily detectable in adults. Although metamorphosis results in profound changes in the lymphoid system associated with the apparent acquisition of self tolerance to new antigens, immunological memory of antigens injected during larval life ofRana andXenopus persists after the metamorphosis period.     

Analysis of theilv-linked genes that determine the morphology ofEscherichia coli Cells

The genetic location ofwee relative tocya was measured by cotransduction with a Tn5 insertion inilv. These experiments locatedwee at 84.8 min in the standardEscherichia coli map. Mutations incya andwee give rise to morphological changes, coccal morphology incya and short rods inwee, suggesting that both may be involved in the pathways of cell elongation. Addition of cAMP to the cultures reverted thecya but not thewee phenotype. Cells ofE. coli in the absence of thewee gene product were, contrary to what has been described forcya cells, as sensitive to mecillinam as in its presence. These results suggested that the action of Wee on elongation is exerted at a level different from that of adenyl cyclase.     

Mechanisms of Na+ uptake,ammonia excretion,and their potential linkage in native Rio Negro tetras (Paracheirodon axelrodi,Hemigrammus rhodostomus,and Moenkhausia diktyota)

Mechanisms of Na⁺ uptake, ammonia excretion, and their potential linkage were investigated in three characids (cardinal, hemigrammus, moenkhausia tetras), using radiotracer flux techniques to study the unidirectional influx (J _in), efflux (J _out), and net flux rates (J _net) of Na⁺ and Cl^?, and the net excretion rate of ammonia (J _Amm). The fish were collected directly from the Rio Negro, and studied in their native “blackwater” which is acidic (pH 4.5), ion-poor (Na⁺, Cl^? ~20 µM), and rich in dissolved organic matter (DOM 11.5 mg C l^?1). J _in ^Na , J _in ^Cl , and J _Amm were higher than in previous reports on tetras obtained from the North America aquarium trade and/or studied in low DOM water. In all three species, J _in ^Na was unaffected by amiloride (10^?4 M, NHE and Na⁺ channel blocker), but both J _in ^Na and J _in ^Cl were virtually eliminated (85–99 % blockade) by AgNO₃ (10^?7 M). A time course study on cardinal tetras demonstrated that J _in ^Na blockade by AgNO₃ was very rapid (<5 min), suggesting inhibition of branchial carbonic anhydrase (CA), and exposure to the CA-blocker acetazolamide (10^?4 M) caused a 50 % reduction in J _in ^Na _.. Additionally, J _in ^Na was unaffected by phenamil (10^?5 M, Na⁺ channel blocker), bumetanide (10^?4 M, NKCC blocker), hydrochlorothiazide (5 × 10^?3 M, NCC blocker), and exposure to an acute 3 unit increase in water pH. None of these treatments, including partial or complete elimination of J _in ^Na (by acetazolamide and AgNO₃ respectively), had any inhibitory effect on J _Amm. Therefore, Na⁺ uptake in Rio Negro tetras depends on an internal supply of H⁺ from CA, but does not fit any of the currently accepted H⁺-dependent models (NHE, Na⁺ channel/V-type H⁺-ATPase), or co-transport schemes (NCC, NKCC), and ammonia excretion does not fit the current “Na⁺/NH₄ ⁺ exchange metabolon” paradigm. Na⁺, K⁺-ATPase and V-type H⁺-ATPase activities were present at similar levels in gill homogenates, Acute exposure to high environmental ammonia (NH₄Cl, 10^?3 M) significantly increased J _in ^Na , and NH₄ ⁺ was equally or more effective than K⁺ in activating branchial Na⁺,(K⁺) ATPase activity in vitro. We propose that ammonia excretion does not depend on Na⁺ uptake, but that Na⁺ uptake (by an as yet unknown H⁺-dependent apical mechanism) depends on ammonia excretion, driven by active NH₄ ⁺ entry via basolateral Na⁺,(K⁺)-ATPase.     

Changes in cell surface anionogenic groups during differentiation ofHerpetomonas samuelpessoai mediated by dimethylsulfoxide

The surface anionic groups of untreated or dimethyl sulfoxide (DMSO)-treatedHerpetomonas samuelpessoai cells were analyzed by cell electrophoresis, ultrastructural cytochemistry, and identification of sialic acids using thin-layer chromatography. Differentiation ofH. samuelpessoai induced by DMSO treatment caused a significant increase in the net negative surface charge. In flagellates exposed to DMSO, more cationized ferritin, colloidal iron hydroxide, and sendai virus particles bound to the cell surface. Treatment of both untreated and DMSO-treated flagellates with neuraminidase decreased markedly the EPM of cells to the cathodic pole. These findings suggest that sialic acid residues are the major anionogenic groups exposed on the surface ofH. samuelpessoai. Thin-layer chromatography showed thatN-acetyl andN,O-diacylneuraminic acids, in equal proportions, were present inH. samuelpessoai. However,N-acetylneuraminic acid predominates in DMSO-treated cells.     

Abnormalities of blood selenium and glutathione peroxidase activity in patients with acquired immunodeficiency syndrome and aids-related complex

Severe protein-calorie malnutrition is common in patients with AIDS and could contribute to the progressive deterioration characteristic of that disease. Selenium deficiency could also have a negative impact on immune function and other organ functions vital for recovery from infectious diseases. Therefore, to assess any role for selenium in AIDS, we determined plasma and erythrocyte selenium levels and glutathione peroxidase activity in 13 patients with AIDS compared to 8 patients with AIDS-related complex (ARC) and 14 healthy controls. Plasma selenium levels were significantly reduced in AIDS patients compared to controls (p<.0001) and to ARC (p<.02). Erythrocyte selenium levels in both AIDS and ARC were also reduced compared to controls (p<.02), but not to each other. Glutathione peroxidase activity in AIDS was 28.9±1.4 U/g Hb vs 38.4±6.9 in ARC (p=NS) and 52.3±1.7 in controls (p<.0001 vs AIDS;p<.02 vs ARC). When all groups were combined, there were significant correlations between total lymphocyte count and both plasma selenium (r=.53;p<.002) and erythrocyte glutathione peroxidase activity (r=.65;p<.0001). In addition, strong correlations were noted between plasma selenium and serum albumin (r=.68;p<.0001), plasma selenium and glutathione peroxidase (r=.77;p<.0001), and glutathione peroxidase and hematocrit (r=.66;p<.0001). In AIDS or ARC, no correlations between selenium with disease duration or weight loss were present. We conclude that, in comparison to normals, patients manifesting infection with human immunodeficiency virus have evidence of selenium deficiency as determined by diminished plasma and erythrocyte levels and glutathione peroxidase activity. These abnormalities are most marked in patients with AIDS, but are also present in patients with AIDS-related complex. Selenium deficiency has important implications for the progression and pathogenesis of clinical disease in AIDS.     

Purification and mass spectrometry based characterization of a pediocin produced by Pediococcus acidilactici 13

Bacteriocins are antimicrobial peptides produced by several bacterial species. Among the bacteriocins pediocin-like bacteriocins have a significant inhibitory activity on the foodborne pathogens especially on Listeria monocytogenes. This study aims to select a simple and usable purification method to purify/concentrate the antimicrobial peptide and characterization of the bacteriocin produced by Pediococcus acidilactici 13 by using proteomic approaches which is a recent omic technology. For purification dialysis, ultrafiltration method was used, and as a result of this study the bacteriocin activity reached 819,200 AU/mL from 102,400 AU/mL initially. Two dimensional gel electrophoresis and then matrix-assisted laser desorption ionization/time of flight mass spectrometry (MALDI-TOF MS) analysis were carried out to identify the current bacteriocin and related proteins. Obtained data revealed similarity to pediocin PA-1 transport/processing ATP-binding protein PedD (accession number: P36497), pediocin operon PedC (accession number: Q68GC4) and bacteriocin pediocin PA-1 (accession number: P29430) from UniProtKB/Swiss-Prot databank, thus the bacteriocin produced by P. acidilactici 13 is considered similar to pediocin PA-1.     

Diversity and antibacterial activities of culturable fungi associated with coral Porites pukoensis

The diversity of coral associated fungi is not enough understood, especially for scleractinian corals. Members of Porites are common and dominant species of scleractinian corals. To date, the fungal communities associated with coral Porites pukoensis have been not reported. In this paper, the diversity and activity of coral associated fungi in P. pukoensis were explored, 23 fungal strains were isolated, belonging to 10 genera and Aspergillus sp. (30.4 %) was predominant fungal genera. The sequence of isolate C1-23 in GenBank was only 90 % similarity to the most closely related sequences. It is concluded that rich fungal symbionts are attached to P. pukoensis, the rate of isolates with antibacterial activity was up to 30 %, particularly some isolates showed stronger bioactivities to gram-negative bacteria. It is included that the diversity of coral associated fungi in P. pukoensis is abundant and its activity is obviously. So the activities of fungi in P. pukoensis were deserved for further study.     

New genera and species of Chrysobalanaceae from Malesia and Oceania

Two new genera of Chrysobalanaceae are described.Hunga distributed in New Caledonia, the Loyalty Islands and Papua and New Guinea, contains eight species, three new, and five formerly placed in the generaAngelesia, Licania andParinari.Kostermanthus is described to accommodate two species with united filaments formerly placed inParinari andAcioa. Both new genera are quite as distinct as others of the family and have been overlooked by undue emphasis placed on the single character of a bilocular ovary.Licania palawanensis Prance is also described; it is the second species of its genus from Malesia.     

Evidence for a fifth (G) region in theH-2 complex of the mouse

Antisera (B10.129×A)F₁ anti-P and (B10×A)F₁ anti-B10.P contain antibodies that define, in the PVP hemagglutination test, an antigen originally described as G or H-2.7. Of the independentH-2 haplotypes, the H-2.7 antigen is present inf, j, k, p, ands. In addition, the antisera also contain a weak cytotoxic antibody, distinct from anti-H-2.7. The cytotoxic antibody reacts with antigens controlled by theK orI regions. The hemagglutinating H-2.7 antibody does not have cytotoxic activity. The genetic determinant coding for antigen H-2.7 can be mapped into the chromosomal segment between theS andD regions. The H-2.7 antigen thus serves as a marker for a new region of theH-2 complex. The locus coding for antigen H-2.7 is designatedH-2 G and the correspondingH-2 regionG. The H-2.7 antigen has a tissue distribution distinct from that of the H-2 antigens controlled by theK orD regions. So far it could be detected primarily on erythrocytes.     

Histogenesis and localization of non-specific esterase in root tip

A procedure was developed for satisfactory freeze-sectioning of root tips. The use of Ca formol-fixed material kept and frozen in Holt's syrup is recommended. The existence and different localization of 2 fractions of non—specific esterase was verified in root tips ofVicia faba. The same results were revealed in fixed and unfixed material. The dynamics ofin situ reaction was followed with respect to optimal incubation time. The results with substrates of different chain length support the existence of 2 fraction of the studied enzyme, none of which, concerning substrate specificity, is a lipase. It follows from the present studies inVicia faba and other species (Cucurbita pepo, Lupinus albus, Pisum sativum Zea mays), that non-specific esterase localization is not directly given by histogenesis.     

Catechol-O-methyltransferase biochemical genetics: Human lymphocyte enzyme

Human erythrocyte (RBC) catechol-O-methyltransferase (COMT) is under genetic control. Experiments were performed to determine whether COMT in the human lymphocyte is regulated in parallel with RBC COMT. Supernatants of lymphocyte homogenates contained COMT activity. However, they also contained a potent COMT inhibitor, the effect of which could be negated by dilution. Lymphocyte COMT activity was maximal at a reaction pH of 7.7 and at a MgCl₂ concentration of 0.67mm. The apparent K _m value for 3,4-dihydroxybenzoic acid, the catechol substrate for the reaction, was 1.2×10^?5 m and that for S-adenosyl-l-methionine, the methyl donor, was 2.3×10^?6 m. An average of 48.3±3.3% (mean ± SEM) of the enzyme activity in crude lymphocyte homogenates from 3 subjects was removed by centrifugation at 100,000 g for 1 hr and was presumed to be membrane associated. The average COMT activity in lymphocytes isolated from blood of 23 randomly selected adult subjects was 14.0±1.2 units/10⁶ cells (mean ± SEM) or 913±69 units/mg protein. There was a significant correlation of relative RBC with relative lymphocyte COMT activity in these 23 subjects. The correlation coefficient was 0.733 (P<0.001) when lymphocyte enzyme activity was expressed per milligram of protein and 0.649 (P<0.001) when lymphocyte activity was expressed per 10⁶ cells. These results are compatible with the conclusion that the genetic polymorphism which regulates RBC COMT activity may also regulate the level of human lymphocyte COMT activity.     

Transplantation and immunoincompatibility reactions among reef-building corals

Intracolony or syngeneic transplants of pieces of living coral, either occurring naturally on reefs or produced experimentally, were consistently compatible. In contrast, intercolony allografts performed extensively inAcropora formosa and inPorites andrewsii were incompatible, as were allografts occurring naturally in additional species observed in reef communities. Diverse interspecific combinations of coral xenografts generally displayed greater incompatibilities. Four levels of immuno-reactivity, with manifestations ranging from mild to severe, were distinguishable as follows: a) contact avoidance reactions, b) allogeneic contact incompatibility, c) chronic xenogeneic incompatibility, and d) acute interspecific aggression.Allogeneic incompatibility, most studied inA. formosa, was characterized by soft tissue contact avoidance wherever possible; absence of tissue death despite extensive enforced contact (18–20 days); and late interfacial cementation terminating allogeneic soft tissue contact. The properties ofchronic xenogeneic incompatibility as found in diverse species combinations, are slow onset (>7 days), bidirectional or unidirectional killing in contact zones, and short-range or localized effectiveness.Acute interspecific aggression initiated byFungia fungites as a dominant “aggressor ” is distinguished by early occurrence (2–7 days) and unidirectional contact killing. The presence or absence of these acute xenogeneic reactions sharply discriminated between species within each of the generaAcropora, Pocillopora, andPorites. No hierarchy of aggressive interactions was evident at the generic level.     

The effect of Sa and MiniSa plasmids on the induction of plant crown galls and hairy roots byAgrobacterium tumefaciens andAgrobacterium rhizogenes

The Inc-W group plasmid Sa or its derivative MiniSa were introduced into two strains ofAgrobacterium tumefaciens with Ti plasmids, one strain ofA. tumefaciens with the Ri plasmid and oneA. rhizogenes strain with the Ri plasmid. The effect was similar in allAgrobacterium strains. The pSa suppressed fully the virulence ofAgrobacterium strains (i.e. their ability to induce tumor growths - crown galls or hairj⁷ roots) inKalanchoe plants and carrot root slices. The MiniSa plasmid caused only a slight decrease of the frequency and size of tumor growths induced. The mechanism of suppression of virulence by the Sa plasmid inAgrobacterium tumefaciens andAgrobacterium rhizogenes seems to be similar.     

Reducing the bioactivity of Tannerella forsythia lipopolysaccharide by Porphyromonas gingivalis

Tannerella forsythia is considered a pathogen of periodontitis and forms a biofilm with multi-species bacteria in oral cavity. Lipopolysaccharide is a powerful immunostimulator and induces inflammation and shock. The purpose of this study was to investigate the characteristics of T. forsythia LPS in its co-cultivation with Fusobacterium nucleatum or Porphyromonas gingivalis. T. forsythia was co-cultured in the presence and absence of F. nucleatum and P. gingivalis and then T. forsythia LPS was extracted. The extracts were analyzed by SDS-PAGE and NF-κB reporter CHO cell lines. THP-1 cells were treated with the LPS and evaluated induction of cytokine expression by real-time RT-PCR and ELISA. For analysis of the bioactivity of T. forsythia LPS, the binding assay on LPS-binding protein (LBP) and CD14 was processed. The extracts did not contaminate other molecules except LPS and showed TLR4 agonists. Co-cultured T. forsythia LPS with P. gingivalis exhibited a lower level of induction of TNF-α, IL-1β, and IL-6 expression than singleor co-cultured T. forsythia LPS with F. nucleatum in the conditions of human serum. However, the three T. forsythia LPS did not show difference of cytokine induction in the serum free conditions. Co-cultured T. forsythia LPS with P. gingivalis exhibited a lower affinity to LBP and CD14 as binding site of O-antigen and attached at a lower level to THP-1 cells compared to single- or co-cultured T. forsythia LPS with F. nucleatum. The virulence of T. forsythia LPS was decreased by co-culturing with P. gingivalis and their affinity to LBP and CD14 was reduced, which may due to modification of O-antigen chain by P. gingivalis.     

RNA silencing of the anionic peroxidase gene impairs potato plant resistance to Phytophthora infestans (Mont.) de Bary

Potato Solanum tuberosum L. plants expressing an antisense M21334 fragment were obtained by agrobacterial transformation. A manifold decrease in activity of anionic isoperoxidase with pI ～ 3.5 in the transformed plants demonstrated that the enzyme is encoded by M21334. The transformed plants showed a decrease in lignin accumulation and a dramatically lower resistance to the late blight agent Phytophthora infestans, implicating the enzyme in the response to P. infestans infection.     

Fumarate reduction inProteus mirabilis

1. Proteus mirabilis formed fumarate reductase under anaerobic growth conditions. The formation of this reductase was repressed under conditions of growth during which electron transport to oxygen or to nitrate is possible. In two of three tested chlorateresistant mutant strains of the wild type, fumarate reductase appeared to be affected.
2. Cytoplasmic membrane suspensions isolated from anaerobically grownP. mirabilis oxidized formate and NADH with oxygen and with fumarate, too.
3. Spectral investigation of the cytoplasmic membrane preparation revealed the presence of (probably at least two types of) cytochromeb, cytochromea ₁ and cytochromed. Cytochromeb was reduced by NADH as well as by formate to approximately 80%.
4. 2-n-Heptyl-4-hydroxyquinoline-N-oxide and antimycin A inhibited oxidation of both formate and NADH by oxygen and fumarate. Both inhibitors increased the level of the formate/oxygen steady state and the formate/fumarate steady state.
5. The site of inhibition of the respiratory activity by both HQNO and antimycin A was located at the oxidation side of cytochromeb.
6. The effect of ultraviolet-irradiation of cytoplasmic membrane suspensions on oxidation/reduction phenomena suggested that the role of menaquinone is more exclusive in the formate/fumarate pathway than in the electron transport route to oxygen.
7. Finally, the conclusion has been drawn that the preferential route for electron transport from formate and from NADH to fumarate (and to oxygen) includes cytochromeb as a directly involved carrier. A hypothetical scheme for the electron transport in anaerobically grownP. mirabilis is presented.