In vitro evaluation of combination of Trichoderma harzianum and chitosan for the control of sapstain fungi

In vitro assays were undertaken to evaluate the control of two sapstain fungi, Leptographium procerum and Sphaeropsis sapinea by a combination of chitosan or chitosan oligomer and an albino strain of Trichoderma harzianum. Spore germination and hyphal growth of the test fungi were assessed on media amended with chitosan or chitosan oligomer with and without T. harzianum using either simultaneous inoculation with test fungus or inoculation 1, 2, or 3 days after pre-infection with test fungus.There was no mycelial growth of the test fungi regardless of chitosan concentrations used when either L. procerum or S. sapinea was simultaneously inoculated with T. harzianum. However, the dose–response of chitosan or chitosan oligomer on the test fungi was apparent when T. harzianum was not simultaneously inoculated with test fungus but introduced later. There was a greater growth reduction at higher concentrations (0.075–0.1% v/v) of chitosan, and overall chitosan oligomer was more effective than chitosan aqueous solution.Chitosan alone was able to restrict or delay the germination of spores but the combination of chitosan and T. harzianum inhibited spore germination and hence colony formation of test fungi regardless of time delay.     

Cytology of collagenous spherulosis of the breast: a diagnostic dilemma – report of three cases

Collagenous spherulosis is a rare incidental finding seen in association with benign breast lesions. Cytological findings in three cases of collagenous spherulosis diagnosed on fine needle aspiration are presented. The presence of hyaline pink globules surrounded by benign myoepithelial cells in Giemsa stained smears was a diagnostic feature. Associated lesions were atypical papillary hyperplasia (2) and fibroadenoma (1). Adenoid cystic carcinoma was the close differential diagnosis on cytology. Awareness of this entity is important to avoid a false positive diagnosis of malignancy.     

Sexual generation and overwintering of the peach leaf curling aphid Brachycaudus helichrysi (Kalt.) in Himachal Pradesh, India

Autumn migrants preferred to settle on the dorsal leaf surface of peach with gynoparae being more numerous than alate males. These return migrants on peach were similar to those described by others except for a comparatively smaller processus terminalis. Among the oviparae with metatibial pseudosensoria. most (62.5%) had six antennal subdivisions; 25% possessed five antennal subdivisions and half of these were parasitised. Oviparae were bigger than those previously described on plum/damson but their processus terminalis was comparatively shorter. Ultimate instar nymphs were without pseudosensoria and had 5–seg-mented antennae, the VI segment being cleaved from the meriston during the final moult. Alate males mated with the oviparae, mating duration being 3 to 6 min. Oviparae contained, at the most, two well developed eggs at one time, and normally deposited eggs singly during November-December. Most eggs hatched within 20–28 days but those laid in December during colder weather took up to 50 days to hatch. By midJanuary most eggs had hatched. Fundatrix developmental rate was dependent on sap-flow. Overwintering occurred as the fundatrix.     

Urinary Steroid Chromatograms from Children

DURING a longitudinal investigation on the changes in urinary steroid profile with sexual maturation in healthy children, a new steroid-like substance, giving most of the well known steroid reactions, was found¹. Since then, the substance has appeared consistently in microgram quantities on urinary steroid chromatograms in our laboratory², running close to 11β-hydroxyandrosterone in the Bush B3 system³. Similar substances have been noted by other workers (Drs D. M. Cathro, C. C. Forsyth and J. Bertrand, personal communications). Children suffering from lipodystrophy, progeria and leucine-sensitive hypoglycaemia excreted this substance in larger quantities than the normals⁴.     

Studies in the Physiology of Parasitism: XXV. Some Propertles of the Pectic Enzymes secreted by Pythium debaryanum

The pectic enzymes of Pythium debaryanum have been comparedwith those from two other soft-rot causing organisms, Erwiniaaroideae and Botrytis cinerea, by their effects (viscosity reduction,acid production, and reducing power) on 1 per cent, solutionsof (a) high methoxyl pectin, (b) sodium polypectate, and (c)sodium pectate (2 types). The Pythium debaryanum preparationdiffered particularly in giving no increase in reducing poweror evidence of galacturonic-acid-like derivatives. It maceratedthe walls of potato-tissue freely but had nopolygalacturonaseor pectinesterase activity.     

Characterization of a Highly pH Stable Chi-Class Glutathione S-Transferase from Synechocystis PCC 6803

Glutathione S-transferases (GSTs) are multifunctional enzymes present in virtually all organisms. Besides having an essential role in cellular detoxification, they also perform various other functions, including responses in stress conditions and signaling. GSTs are highly studied in plants and animals; however, the knowledge regarding GSTs in cyanobacteria seems rudimentary. In this study, we report the characterization of a highly pH stable GST from the model cyanobacterium- Synechocystis PCC 6803. The gene sll0067 was expressed in Escherichia coli (E. coli), and the protein was purified to homogeneity. The expressed protein exists as a homo-dimer, which is composed of about 20 kDa subunit. The results of the steady-state enzyme kinetics displayed protein’s glutathione conjugation activity towards its class specific substrate- isothiocyanate, having the maximal activity with phenethyl isothiocyanate. Contrary to the poor catalytic activity and low specificity towards standard GST substrates such as 1-chloro-2,4-dinitrobenzene by bacterial GSTs, PmGST B1-1 from Proteus mirabilis, and E. coli GST, sll0067 has broad substrate degradation capability like most of the mammalian GST. Moreover, we have shown that cyanobacterial GST sll0067 is catalytically efficient compared to the best mammalian enzymes. The structural stability of GST was studied as a function of pH. The fluorescence and CD spectroscopy in combination with size exclusion chromatography showed a highly stable nature of the protein over a broad pH range from 2.0 to 11.0. To the best of our knowledge, this is the first GST with such a wide range of pH related structural stability. Furthermore, the presence of conserved Proline-53, structural motifs such as N-capping box and hydrophobic staple further aid in the stability and proper folding of cyanobacterial GST- sll0067.     

Differential protein expression in the metal-reducing bacterium Geobacter sulfurreducens strain PCA grown with fumarate or ferric citrate

Geobacter sulfurreducens, generally considered to be a strict anaerobe, is a predominant microbe in subsurface environments, where it utilizes available metals as electron acceptors. To better understand the metabolic processes involved in the metal-reduction capability of this microbe, the proteins expressed by cells grown anaerobically with either fumarate or ferric citrate as electron acceptor were compared. Proteins were separated by 2-DE under denaturing or nondenaturing conditions, and proteins varying in abundance with a high level of statistical significance (p<0.0001) were identified by peptide mass analysis. Denaturing 2-DE revealed significant differences in the relative abundance of the membrane proteins OmpA and peptidoglycan-associated lipoprotein, several metabolic enzymes, and, in addition, superoxide dismutase and rubredoxin oxidoreductase. Nondenaturing 2-DE revealed elevated catalase in cells grown with ferric citrate. These results suggest that, in addition to adjustments in membrane transport and specific metabolic pathways in response to these two different electron acceptors, distinct differences exist in the oxidative environment within the cell when fumarate or soluble ferric citrate is provided as electron acceptor. Although an anaerobe, G. sulfurreducens appears to have alternate mechanisms for dealing with reactive oxygen species in response to increased intracellular soluble iron.     

Preferential Growth of Haploid Plant Cells <Emphasis Type="Italic">in vitro</Emphasis>

HAPLOIDS from higher eukaryotes are of great importance for genetic analysis¹. The observation of Morpurgo² that haploid segregants can be obtained from diploid lines of Aspergillus nidulans by parafluorophenylalanine (PFP) treatment suggests that defined chemical manipulations may be useful in generating and maintaining haploid cells in cultures of higher plants. Parafluorophenylalanine has been found to induce haploidization not only in some species of Aspergillus, but also in some other genera of fungi such as Ustilago³.     

Leucine Aminopeptidase Activity in Tall and Dwarf Cultivars of Rice at Successive Stages of Development

Studies to determine the variations in leucine aminopeptidase(LAP) activity in tall and dwarf cultivars of rice were conductedby horizontal starch gel electrophoresis. The samples were takenat weekly intervals starting with soaked seeds (12 h) untilthe post-panicle stage. There is a distinct pattern of LAP isoenzymesin tall and dwarf cultivars studied. Some isoenzymes appearat a particular developmental stage and others disappear whilesome remain fairly constant once they are formed. A tall cultivar(Hansraj) shows greater fluctuations during the course of developmentthan the dwarf cultivars. These studies throw light on the transitorynature of these enzymes and show apparently differential geneaction.