Morphogenesis in the Mycelium: Control of Lateral Hypha Frequency in Mucor hiemalis by Amino-Acids

A method is described for the perfusion of growing mycelialmargins with solutions and for the measurement of their effectupon the frequency of lateral hypha production. Perfusion with water induces in Mucor hiemalis Wehm. a highlateral branch frequency which is only moderately diminishedif a minerals+ thiamin+ glucose solution is used. Additionsof various materials to this basal solution may promote or stronglydepress lateral branching. Internode lengthening agents areenzymic digest of casein, or its acid hydrolysate or dialysate,at pH 50. About half the activity of casein hydrolysate is foundwith favourable mixtures of amino-acids, and with arginine orlysine. Some degree of activity is also found with six otheramino-acids alone, Ca(NO₂)₂, uracil plus adenine, and otheras yet unidentified materials. Internode shortening effects are demonstrated for five amino-acidsand asparagine. Evidence is given of interactions between acids. Growth of the fungus for 14 hours removes the internode lengtheningquality from dilute malt-extract medium, and during the sametime its amino nitrogen is markedly reduced. Various inactive materials are mentioned and possible mechanismsof activity are discussed.     

Primary cutaneous coccidioidomycosis; the criteria for diagnosis and a report of a case

Study was made of a case of coccidioidomycosis known to have resulted from primary inoculation of the organisms into the skin. Clinical observations and laboratory data were obtained at the time of clinical illness and for a period of five years thereafter. From the information thus obtained and correlation of it with what already was known of coccidioidomycosis, it was concluded that the disease originates very rarely as the result of primary cutaneous inoculation. In most instances lesions suspected to be of this type have actually resulted by dissemination of the organisms to the skin from a previously unrecognized pulmonary focus. Primary cutaneous coccidioidomycotic lesions closely resemble the primary cutaneous lesions (chancres) in other infectious granulomata, such as syphilis, tuberculosis and sporotrichosis. Spontaneous involution should occur within three months and then there should be immunity to reinfection in all but one or two per thousand instances. From these observations certain criteria were evolved by which to determine in a case of coccidioidomycosis with cutaneous manifestations whether or not the infecting organism entered through the skin.     

Nutritional and Other Aspects of Fruit-body Production in Pure Cultures of Collybia velutipes (Curt.) Fr.

Fruit-body production of Collybia velutipes on a synthetic mediumconsisting of minerals, asparagine, sucrose, and vitamin B₁has been studied. Compared with others tested this medium favouredfructification rather than mycelium growth. Primordia aroseon culturea between pH 5•2 and 7•2 approximately.Relatively low initial concentration of asparagine, high initialconcentration of sucrose, and increases in volume (without essentialincrease of the air interface) of media resulted in enhanceddry weights of sporophore crops. These factors variously affectedmycelium yields and the times of primordium production. Detailsof growth, sporophore production, maximum yield, and changesin the medium are given.     

Evolution in Apiales: nuclear and chloroplast markers together in (almost) perfect harmony

Relationships within the angiosperm order Apiales have long been difficult to interpret. Traditionally, the order comprised two families, Apiaceae and Araliaceae. Recent studies, however, suggest three additional lineages should also be recognized in the order (Pittosporaceae plus two tribes segregated from Araliaceae, Mackinlayeae and Myodocarpeae), and that one taxon (Apiaceae subfamily Hydrocotyloideae) is polyphyletic. Nuclear data also support the placement of five enigmatic genera ( Aralidium , Griselinia , Melanophylla , Pennantia and Torricellia ) within an expanded Apiales. To date, detailed molecular studies of Apiales have relied largely on data derived from plastid sequences, especially mat K and rbc L. To test and complement the results of these studies, the 26S (large subunit) of nuclear ribosomal DNA was sequenced and analysed phylogenetically. Results from this study confirm that Apiales comprise five major lineages: core Apiaceae, core Araliaceae, Pittosporaceae, the Mackinlaya group and the Myodocarpus group. Moreover, using an expanded sampling of members of subfamily Hydrocotyloideae, the nature and extent of the polyphyly is confirmed, with members of this taxon found among four distinct clades within Apiales. © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 144 , 123–147.     

The Change of Tropism in Polyporus brumalis Stipes and the Effect of Directional Stimuli on Pileus Differentiation

The directional influences of light and gravity upon the developmentof pileate and epileate sporophores of Polyporus brumalis, producedin pure culture, have been investigated. Growth in the dimiticfruit-body has a considerable subapical component which in thestipe is responsible for tropistic curvature. The stipe is competentto react negatively to unilateral gravitational and positivelyto unilateral photic stimulation throughout development, butwhen both stimulioperate phototropism masks geotropism. If illuminatedfrom one side the growing epileate stipe is strongly positivelyphototropic but as the pileus reaches a characteristic diameterthe stipe becomes negatively geotropic. Experiments with changingdirection of illumination and with artificial pilei of blackpaper suggest that the change of tropism is explicable by theshading action of the expanding pileus on the sub-pilcal photoperceptiveand photoreactive region of the stipe. Developing sporophores continuously rotated with reference tofixed directions of gravitational and light stimulation andothers with stipes inverted as a result of illumination frombelow during development have in common that the morphologicallyupper surface of the pileus always develops towards and approximatelyat right angles to the direction from which the maximum lightintensity is received. Normal but inverted stipes and dissepimentsshow no tendency to geotropic reorientation.     

The Influence of Factors of the Aeration Complex and Light upon Fruit-body Form in Pure Cultures of an Agaric and a Polypore

Methods involving controlled temperature and illumination, continuouslyrenewed sterile culture atmosphere of defined gaseous compositionand vapour pressure, and automatic replacement of water lossfrom the medium have been applied to the analysis of sporophoreform in Collybia velutipes and Polyporus brumalis. In P. brumalisprogressive suppression of the pileus but enhanced stipe elongationoccurs as light intensity (over a certain range) or transpirationalwater-loss are reduced. These factors act additively. Cap expansionin C. velutipes requires light and is, in addition, inhibitedby an atmospheric staling agent removable by KOH and replaceableby CO₂. Data and observations on conditions affecting timesof production, numbers and dimensions of fruit-bodies are given,especially for P. brumalis. Other aeration factors are consideredbut shown to have no morphological effect.     

Translocation and Pileus Formation in Polyporus brumalis

The already-known promotion of pileus formation in pure culturesof Poly-porus brumalis by heightened evaporating conditionsis shown to be associated with enhanced translocation ratesinto the fruit-body (as investigated by dyes). This does notresult in changed proportions of dry matter or potassium inthe tissues at the stipe apex, but accelerated growth (dry-weightbasis) occurs in this region. Reduction of concentration ofthe medium (and hence probably of the concentration of the translocationstream) diminishes pileus production. Light intensity has onlya minor effect on dye transport. Fruit-bodies arrested in growthor killed show a negligible capacity for dye transport.