Studies on the Growth of Basidiomycetes in Soil

Fructifications of basidiomycetes have been collected at LakenheathWarren, and thirty-nine species have been obtained from fivegrassland soils. The different soils have been found to havedifferent species growing upon them and most species occur onthe alkaline-slightly acid grasslands. Highly acid grasslandat Lakenheath has a poor fungus flora. Studies have been made of the regions in the soil in which themycelia of certain of these basidiomycetes occur, and attemptshave been made to isolate these fungi from soil. Some specieshave been found to inhabit the litter zone rather than the minerallayers of the soil. A few form extensive rhizomorph systemswhich may penetrate deeply into the soil. A few species of ringfungi, such as Marasmius oreades, Psalliota arvensis, and Tricholomanudum, have been found to possess a well-defined mycelial zonein the soil, from which the fungus could be isolated. Profile studies have shown that the mycelial zones of thesespecies contain a restricted population of microfungi, bothfewer species and fewer colonies, as compared with the normalsoil around. Ascomycetes, such as Arachniotus, Chaetomium, Gymnoascus,and Penicillium, have been isolated more frequently from mycelialzones than from normal soil.     

The Diatom Genus Tabellaria: II. Taxonomy and Morphology of the Plankton Varieties

Plankton samples of Tabellaria from all the lakes of the EnglishLake District have been examined and evidence of morphologicallydistinct populations has been found in samples from (a) a singlelake at one time, (b) different lakes, and (c) a single lakeat different times. Clone cultures have been used to study thenature of these differences. Fifteen characters have been foundto show quantitative or qualitative variation in plankton populationsof Tabellaria, and the morphological diversity of differentpopulations is largely due to different combinations of thesecharacters. All known plankton populations of Tabellaria arereferred to the species T. flocculosa.     

Starch Grain Casts and Moulds in Eocene (Tertiary) Fossil Mangrove Hypocotyls

Further examples of the recently reported fossil starch graincasts and moulds in the fossil mangrove Ceriops cantiensis Chandlerfrom the London Clay (Eocene) of the Isle-of-Sheppey, Kent,England have now been discovered. In addition, similar structureshave been found in the fossil hypocotyls of Palaeobruguieraelongata Chandler from Herne Bay, Kent and also in four recentlycollected hypocotyls of a new species of fossil mangrove fromSheppey. Starch grains from herbarium material of the extantmangrove genera, Bruguiera and Ceriops, have been examined forcomparison with the fossil forms. starch grain casts, fossil, mangrove, hypocotyls, palaeobotany, Eocene, framboids, Rhizophoraceae, Bruguiera sexangula, Ceriops cantiensis, Palaeobruguiera elongata     

Physiologic Races of the Brown Rust of Brome Grasses

A number of cultures of the brown rust of Brome grasses havebeen isolated and maintained as single-spore strains. By theirinfection reactions on a representative selection of Brormusspp. at least five physiologic races have been characterized.Two of these have host-ranges confined to a single section ofthe genus, but others have a much wider host-range within thegenus. The uredospore stage of all was identical. Studies ofthe teleutospores have been limited and knowledge of the speciesof rust involved is incomplete. All belong to the group-speciesPuccinia dispersa Erikss. & Henn.; the species P. brominaErikss. and P. symphyti-bromorum Müller were included amongthe cultures studied, possibly also P. bromi-maximi Guyot. Ina large series of inoculations, over a period of in all 14 years,all physiologic races have been remarkably stable in their infectiontypes and host-range, and no confirmation of Marshall Ward's‘bridging-host’ theory has been obtained. Cultivationof two physiologic races for 164 generations on Bromus arduennensis,a species considered by Ward to have special significance asa bridging-host, induced no changes in their host-range.     

Observations with the Electron Microscope on Biciliate and Quadriciliate Zoospores in Green Algae

Quadriciliate zoospores of Draparnaldia and biciliate zoosporesof Chaetomorpha have been examined using our previous methods.New features have been seen in both, chiefly in connexion withthe basal organs which attach the cilia to the cytoplasm ofthe parent cell.     

The Olfactory System as a Model for the Analysis of the Contribution of Gene Expression to Programmed Cell Death

The process of programmed cell death is frequently attenuatedby inhibitors of protein and RNA synthesis. This implies thatgene expression is necessary for the active elimination of somecell types. Genes such as bcl-2 and bax have been implicatedin the direct control of cell death, while cellular immediate-earlygenes (clEGs), such as c-fos and c-jun have been repeatedlyassociated with neuronal degeneration. We are using the olfactoryneuroepithelium as a model system to investigate the role thatexpression of such genes might play in cell death. The advantagesof this system is that even in the adult, there is spontaneousdegeneration of olfactory receptor neurons followed by theirreplacement by the division and differentiation of precursors.Futhermore, the receptor neurons can be induced to die synchronouslyby removal of the olfactory bulb or intranasal administrationof toxic agents. We have generated fos-lacZ and jun-lacZ transgenicmice that can be used to assess expression of c-fos and c-junfollowing these various manipulations. In addition, a line oftransgenic mice has been derived that express Bcl-2 under thecontrol of the olfactory receptor protein promoter. These micehave high levels of Bcl-2 selectively in receptor neurons ofthe primary neuro-epithelium and vomeronasal organ. Since insome circumstances, Bcl-2 can protect against programmed celldeath these mice are being assessed for neuronal turnover underbasal conditions and following olfactory bulbectomy.     

SIZE AND SEX IN CYPRAEIDAE

Samples of Cypraea (Notocypraea) angustata Gmelin 1791 and ofCypraea errones L. 1758 have been measured, and the sex of theindividuals determined. The males of C. angustatawere foundto be significantly shorter than the females. Differences betweenother dimensions in this species, and between all dimensionsmeasured in C. errones, were of little significance It has recently been shown (Griffiths, 1961) that the malesof Umbilia hesitata Iredale were greater in length than thefemales. Other evidence in this paper, and some subsequent measurementsmade by Schilder and Schilder (1961) have suggested that theconverse might be true for some other species of CYPRAEIDAE Sample groups of shells of C. errones and C.(N) angustata havenow been measured. The shells were then cut open, and thesexof the animal determined by the presence or absence of a penis.The results are givenin Tables I and II (Received 10 March 1961;     

A Comparative Study of Certain Seed Isoenzymes in the Ten Chromosome Complex of Brassica Campestris and its Allies

A gel electrophoretic study has been carried out on the seedisoenzymes of n = 10 members of the genus Brassica. Eleven isoenzymesystems have been studied and the distribution of the isoenzymesused to indicate a possible relationship between the major recognizedtaxa. Three basic centres of the complex have been indicated:Indo-European, China and Mediterranean as exemplified by B.campestris (turnip/turnip-rape), B. chinensis and B. tournefortii(wild turnip) respectively.     

Observations on Phragmosomes

Bodies thought to be equivalent to the phragmosomes describedby Porter and Caulfield in Onion root tips have been demonstratedin the cytoplasm of Equisetum (mother cell), Pinns (embryo),and Anthoceros (capsule meristem). Their behaviour during stagesof mitosis from metaphase to telophase has been traced in Anthocerosand they have been shown to persist and perhaps to increaseafter mitotic growth has ceased. Though commonly associatedin a characteristic way with the spindle and cell plate, thereis no positive evidence in favour of a causal connexion witheither. Bipartition of individual phragmosomes occurs in relationto the equatorial plane of the spindle but multiplication mayalso occur in other ways at other times. No function can yetbe assigned to them nor has a developmental sequence been traceablebetween phragmosomes and any other cell component. They aretherefore provisionally regarded as organelles sui generis.     

Descriptions of some planktonic larvae of the Calappidae (Crustacea: Decapoda; Brachyura)

Some unidentified planktonic larval stages have been assignedto the Calappidae using Rice's key of Brachyura families. Zoeastage I from the eastern region of the Algerian coast (westernMediterranean Sea) has been attributed, according to Manningand Holthuis (1980), to Calappa granulata (L.), the only recordedrepresentative of the family from the Mediterranean Sea. Zoealstages 1-lV from the Jordanian coast of the Gulf of Aqaba, NorthernRed Sea, have been reported to the subfamily Matutinae. Comparisonsof larvae of Calappa and of Hepatus and then, of larvae of Hepatusand of Matuta, show that Hepatus larvae are more closely relatedto those of Calappa, while those of Matuta are clearly distinct.It s suggested to place the genus Hepatus with the Calappinae.Guinot (1966. 1978) placed some genera, including Hepatus. ina 'unit parthenoxystomienne, lea Aethrinae'. Larval developmentis unknown for Aethra, Actaeomorpha. Hepatella andOsachila.However, comparison of Hepatus larvae with those of Parthenopidaeshows that larval characters, particularly the setation of theendopod of the first maxilliped, are not conclusive for supportingsuch a regrouping. Moreover, the Calappidae have a combinationof primitive and advanced features which suggest that theirgrouping in the Oxystomata seems more likely to be an adaptationto a similar way of life. The morphotypal taxon Oxystornatahas been definitively rejected by Guinot (1978).     

Observations on the Life History of the Haptophycean Alga Pleurochrysis scherffelii with Special Reference to the Microanatomy of the Different Types of Motile Cells

The coccolith-bearing phase of Pleurochrysis scherffelii hasbeen examined with the electron microscope for the first time.Coccolith and scale structure, haptonema morphology, and themicroanatomy of the protoplast have been recorded and shownto agree closely with those of Hymenomonas carterae and theHymenomonas stage of Apistonema previously investigated by thepresent author. Comparative observations have been made on thevegetative phase and non-coccolith-bearing swarmers of Pleurochrysisscherffelii and these differ significantly in scale morphologyfrom the coccolith-bearing phase although the haptonema of theswarmers is similar. Certain developmental observations havebeen included in the investigation and the taxonomic significanceof the findings is discussed in a preliminary way.     

The Effects of Griseofulvin on Certain Phytopathogenic Fungi

In vitro and in vivo investigations have been carried out intothe reaction of actively growing hyphae of Botrytis spp. onencountering an environment containing griseofulvin. In vitro, the reactions noted were slowing of the growth rate,stimulation to branching, abnormal appearance of hyphal protoplasm,and loss of rigidity of the hyphal membrane in the region ofthe tip. The antibiotic is not translocated within the mycelium. In vivo, Botrytis tulipae was incapable of penetrating cellmembranes in the stem of tulips watered with griseofulvin. Theantibiotic was shown to delay or to prohibit the penetrationof onion epithelium by B. allii, depending on concentration.The characteristic curling and stunting of hyphae caused bygriseofulvin have both been observed to occur in plant cells.     

A Study of 'Phloeotracheids' in Haustoria of Santalaceous Root Parasites using Scanning Electron Microscopy

Tracheary elements within haustoria of six santalaceous rootparasites have been examined by scanning electron microscopywith particular reference to those cells which contain granules.These cells have been called ‘phloeotracheids’ byearly workers. The granules lie free within the lumen of thecell from which a protoplast is absent at maturity. The granulesoccur in short vessel elements and in imperforate cells whichare thought to represent a specialized type of tracheid. Phloeotracheidsare confirmed in Exocarpus bidwilliiand Mida salicifolia andreported for the first time in Buckleya distichophylla, Comandraumbellata, Nestronia umbellataand Pyrularia pubera. The structureof phloeotracheids shown by scanning electron microscopy isdiscussed in relation to previous studies.     

Tumour-like anomalies on copepods may be wounds from parasites

Tumour-like anomalies have been reported from planktonic copepods,and these protuberances have been suggested to be cancer tumoursor Ellobiopsid ectoparasites. However, endoparasites, such asBlastodinium, may also produce such protuberances that persistafter the parasite has left its host.     

Electron Microscopic Observations of the Structure of Sieve-connexions in the Phloem of Angiosperms and Gymnosperms

The sieve elements of Pinus silvestris L., Sorbus aucupariaL., Vitis vinifera L., and Cucurbita pepo L. have been examinedelectron microscopically in ultra-thin section, and the structuresof the corresponding sieve areas or sieve plates have been describedand compared. In Pinus the sieve areas contain groups of connectingstrands which enter the wall from the lumen side as individualsbut coalesce within it in the median cavity. This cavity hasdeveloped by wall breakdown in the middle lamella and primarywall region and corresponds to the median nodule visible undera light microscope. Neither in this nor in the other speciesobserved is there any visible closing membrane. Structural differences between the four species are shown tosuggest that the major evolutionary trend in the evolution ofspecialized conducting strands has been the enlargement of theconnecting strands from groups of small separate strands toa smaller number of larger strands as the median cavity becomesenlarged to form a canal through the wall. The connecting strands appear invariably to be dense, highlyosmiophilic and continuous with the cytoplasmic surface of thecell. No signs of micropores or of other tubular structure inthe strands have been found. The structures thus revealed aremore nearly compatible with active transport of materials acrossthe sieve plate than they are with any purely physical mechanism.It is suggested that they are incompatible with any mass flowhypothesis.     

Character Displacement in Frogs

Additional evidence has accumulated over the past 20 years regardingthe significance of the anuran mating call and regarding reinforcementof this premating isolating mechanism when hybridization occursin zones of symnatry. No two sympatric species have the samecall. That the mating call is a home-specific mate attractanthas been demonstrated in five major anuran families. Discriminationagainst hybrid calls versus homospecific calls has been demonstratedin Bufo and Hyla. Principal examples of presumed reinforcementcontinue to be in Gastrophryne, Acris, and the Australian Hylaewingi group. Reinforcement may be the basis for striking differentiationof some populations of Scaphiopus bombifrons. Sympatric speciespairs of anurans show greater differentiation in call than doallopatric pairs in the same group. One hybridizing situationin Bufo appears to have changed over 30 years to discrete populationswithout intermediate calls. Effective call differences can evolvewithout sympatry, and there are sympatric situations in whichno reinforcement is evident.     

The origin of metazoan complexity: porifera as integrated animals

Sponges [Porifera] are the phylogenetically oldest metazoanphylum still extant today; they share the closest relationshipwith the hypothetical common metazoan ancestor, the Urmetazoa.During the past 8 years cDNAs coding for proteins involved incell-cell- and cell-tissue interaction have been cloned fromsponges, primarily from Suberites domuncula and Geodia cydoniumand their functions have been studied in vivo as well as invitro. Also, characteristic elements of the extracellular matrixhave been identified and cloned. Those data confirmed that allmetazoan phyla originate from one ancestor, the Urmetazoa. Theexistence of cell adhesion molecules allowed the emergence ofa colonial organism. However, for the next higher stage in evolution,individuation, two further innovations had to be formed: theimmune- and the apoptotic system. Major defense pathways/moleculesto prevent adverse effects against microbes/parasites have beenidentified in sponges. Furthermore, key molecules of the apoptoticpathway(s), e.g., the pro-apoptotic molecule comprising twodeath domains, the executing enzyme caspases, as well as theanti-apoptotic/cell survival proteins belonging to the Bcl-2family have been identified and cloned from sponges. Based onthese results—primarily obtained through a molecular biologicalapproach—it is concluded that cell-cell- and cell-matrixadhesion systems were required for the transition to a colonialstage of organization, while the development of an immune systemas well as of apoptotic processes were prerequisites for reachingthe integrated stage. As the latter stage already exists insponges, it is therefore likely that the hypothetical ancestor,the Urmetazoa, was also an "integrated colony."     

Morphological characterization of adult Artemia (Crustacea, Branchiopoda) from different geographical origins. American populations

The morphological characterization of adult Artemia femalesbelonging to 25 different populations from all over the Americashas been accomplished. The measures of 12 different parametershave been taken from individuals of each population raised understandardized culture conditions from nauplii to adult. Theyhave been analyzed through multivariate discriminant proceduresin order to establish relationships among the different populations,as well as to have a tool to assign new sets of data for unknownpopulations to one of the groups analyzed here. We have beenable to clearly separate the populations of the two differentspecies analyzed (Artemia persimilis and Artemia franciscana).In addition, we distinguish three different clusters of populationsamong the A.franciscana populations: North American athalassicinland populations, individuals from the Caribbean coast areaand populations from the Pacific Ocean shore.     

Understanding vertebrate brain evolution

Four major questions can be asked about vertebrate brain evolution:1) What major changes have occurred in neural organization andfunction? 2) When did these changes occur? 3) By what mechanismsdid these changes occur? 4) Why did these changes occur? Comparativeneurobiologists have been very successful in recognizing majorchanges in brain structure. They have also made progress inunderstanding the functional significance of these changes,although this understanding is primarily limited to sensorycenters, rather than integrative or motor centers, because ofthe relative ease of manipulating the relevant stimuli. Althoughneuropaleontology continues to provide important insights intowhen changes occurred, this approach is generally limited torecognizing variation in overall brain size, and sometimes brainregions, as interpreted from the surface of an endocranial cast.In recent years, most new information regarding when neuralchanges occurred has been based on cladistical analysis of neuralfeatures in extant taxa. Historically, neurobiologists havemade little progress in understanding how and why brains evolve.The emerging field of evolutionary developmental biology appearsto be the most promising approach for revealing how changesin development and its processes produce neural changes, includingthe emergence of novel features. Why neural changes have occurredis the most difficult question and one that has been the mostignored, in large part because its investigation requires abroad interdisciplinary approach involving both behavior andecology.