Genetic variation in the orientation of nuclear spindles during the development of asci in Neurospora

The effect of a single mutant gene, peak-2, in Neurospora crassa is to alter the ascus from one in which the eight spores are linearly arranged to one in which the eight spores are arranged non-linearly. The same gene transferred to N. tetrasperma determines an ascus similar to that of the mutant N. crassa but in striking contrast to the normal ascus for N. tetrasperma, which includes four heterokaryotic spores, linearly arranged. A comparative cytological study has been made on asci from both species, including material from zygotes that are homozygous normal, heterozygous for peak-2, and homozygous for peak-2. The observed morphogenetic differences are closely related to differences in nuclear spindle orientation, which in turn are correlated with the geometry of the cell. The observations are shown to bear on the basis of pseudohomothallism in N. tetrasperma. Speculations on the importance of the cell wall in relation to spindle orientation are presented. Differences of expression of peak-2 in the different species are discussed.     

Reperti Teratologici in Tulipa Gesneriana L. Var. Spathulata (Bert.)

Summary

Here is described by the author a teratological case of Tulipa Gesneriana L. v. spathulata (Bert.) which is notable for the concomitance of several anomalies in a single individual:

a) irregular number of the leaves;

b) scape ending with three flowers which are anomalous;

c) two from the above mentioned flowers have tetracarpellary pistil;

d) the third flower has an androecium which is formed by three external stames and, besides, by three other stames which are smaller than the first-ones and are also inglobed in a bypertrophic esacarpellary pistill.     

Re-validation of Gonorhynchus adiscus and G. diplochilus (Teleostei: Cyprinidae) using morphological and molecular data

Small and silvery cyprinid species from eastern Iran which are usually known as Crossocheilus latius are reviewed based on morphological and molecular characters of the mtDNA COI barcode region. We demonstrate that fishes which had been identified as Crossocheilus Kuhl & van Hasselt, 1823 in Iran actually belong to the genus Gonorhynchus McClelland, 1838 with two species: G. adiscus (Annandale, 1919) and G. diplochilus (Heckel, 1838), which are rediagnosed here. Both species are well distinguished by gill raker counts, number of scales between anus and anal fin, barbel size and minimum body depth. G. adiscus and G. diplochilus are also distinguished by molecular characters of the mtDNA COI barcode region. Both species are phylogenetically close to Gonorhynchus latius (Hamilton, 1822) which is restricted to India, Nepal and Bangladesh and to G. burmanicus (Hora, 1936), restricted to India and Myanmar. All of these four related taxa are phylogenetically closer to the genus Garra than the genus Crossocheilus (restricted to south-east Asia).     

Early Palaeogene Louisinidae (Macroscelidea,Mammalia), their relationships and north European diversity

Seventeen species from the Palaeocene and Early Eocene of northern Europe, of which 12 are new, are described belonging to the extinct macroscelidean family Louisinidae, raised here from subfamily rank. These species belong to nine genera, of which five are new. The new genera are Walbeckodon , Berrulestes , Gigarton , Thryptodon , and Prolouisina . The new species are Walbeckodon krumbiegeli , Walbeckodon girardi , Paschatherium levei , Berrulestes phelizoni , Berrulestes pellouini , Berrulestes poirieri , Gigarton meyeri , Gigarton sigogneauae , Gigarton louisi , Thryptodon brailloni , Louisina marci , and Teilhardimys brisswalteri . Prolouisina is erected for ‘Louisina’atavella Russell, 1964. Cladistic analysis was undertaken to understand the relationships within the Louisinidae and between them and the North American family Apheliscidae, in which they had earlier been included as a subfamily. Louisinidae are shown to be sister group to a clade consisting of Apheliscidae plus Amphilemuridae and part of a paraphyletic and polyphyletic Adapisoricidae, all of which are tentatively considered to be stem members of the order Macroscelidea. The most primitive macroscelidid, Chambius, from the Early Eocene of northern Africa is nested within Apheliscidae when postcranial characters were included, but in a majority of cases within the Louisinidae when postcranial characters were excluded. Most species from northern Europe became extinct at the end of the Palaeocene, although the genus Paschatherium survived for much of the Early Eocene and Teilhardimys survived into the earliest Eocene. © 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 164 , 856–936.     

Tissue-specific expression of the PAL3 promoter requires the interaction of two conserved cis sequences

The bean PAL2 and PAL3 promoters confer expression in overlapping sets of tissue types in transgenic tobacco. The PAL3 promoter contains motifs that resemble two AC cis elements which are required for tissue-specific expression of the PAL2 promoter. The functions of these motifs in the PAL3 promoter were determined by analysis of mutated PAL3 promoter-GUS constructs in transgenic tobacco. This revealed that the AC motifs are necessary for tissue-specific expression of the PAL3 promoter. Therefore, a key role is indicated for AC elements, which are Myb-protein binding sites, in regulating tissue-specific expression of the bean PAL gene family.     

The question of cosmopolitanism in the deep-sea ostracod fauna: the example of the genus Pedicythere

Deep-sea Pedicythere species which had been earlier considered as pan-abyssal in distribution are shown to be composite species including similar, but separate species in the Pacific, Indian and Atlantic oceans. Morphology and distribution of Pedicythere are analysed. A key to well-described Cenozoic species and forms in open nomenclature which are referred to Pedicythere is presented, together with an annotated checklist of species. Five new species of Pedicythere are described from the South China Sea: P. hirundo sp. nov., P. gibbera sp. nov., P. dentata sp. nov., P. arator sp. nov. and P. nivea sp. nov.     

A genetic and biochemical study of streptomycin- and spectinomycin-resistance in Salmonella typhimurium

Summary In Salmonella typhimurium, streptomycin resistance can occur by mutation at the strA or the strB mutants have altered ribosomes which are refractory to the drug in cell-free amino acid incorporation systems, and in ³H-dihydrostreptomycin binding studies. StrB mutants, unlike the strA mutants, are resistant to several aminoglycoside antibiotics and resistance is not due to a mutational change in the cell's protein synthetic machinery. Spectinomycin resistant mutants of S. typhimurium also fall into two classes, only one of which is ribosomal in mechanism. The spcA and spcB loci are closely linked to strA, aroC, and argG on the S. typhimurium linkage map.     

New species and new records of smut fungi from China

This paper deals with six species of smut fungi which were collected in the provinces Yunnan and Gansu in China. Among them, Anthracoidea yunnanensis and Entorrhiza guttiformis are new species. Sporisorium andropogonis-annulati, which is a new combination, Sporisorium montaniensis, Urocystis pseudoanemones, and Ustilago griffithsii are new records for China.     

Expression of fungal genes involved in penicllin biosynthesis

Carbon catabolite repression and pH regulation are regulatory circuits with a wide domain of action in the Plectomycetes. Penicillin biosynthesis is one of the pathways which are under their control. The conclusions obtained so far, which are based on studies of the genetic and molecular regulation of the penicillin pathway of Aspergillus nidulans, would have been much harder to produce using an organism such as Penicillium chrysogenum (the industrial penicillin producer). However, A. nidulans and P. chrysogenum are close in terms of their phylogeny and one can reasonably predict that the conclusions about A. nidulans, which are summarized in this review and which are of unquestionable biotechnological relevance, will be extrapolable to the industrial organism.     

Recenti progressi e problemi nelle ricerche pteridologiche

Abstract

Recent advances and problems in pteridological research. - The first part of this invited lecture deals with the taxonomic position of the Pteridophyta in the Vegetable Kingdom (Chart 1) and particularly the recognition of them as an independent division, distinct from Bryophyta as well as from Spermatophyta but nearer the latter than to the former. Accordingly, in the author's opinion, the Cormobionta can be subdivided into two main groups (Chart 1, and Fig. 2): the Bryophytonta, with the sole division of Bryophyta, and the Stelophytonta, consisting of the Pteridophyta and Spermatophyta. The Bryophytonta are regarded as a conservative phyletic line with low perspective power, running independently since the most remote time from the Stelophytonta (Fig. 1), which, rich in evolutive potentialities, were by far more successful than the former. The extant Pteridophyta are classified according to the scheme proposed by the author in 1977, which shows all taxa from the rank of subdivision to that of family (Chart 2).

The second part of the lecture is mainly devoted to the results of some recent cytogenetic investigations on the Pteridophytes. First of all, information is given on the processes by which the diploids give rise to other entities mainly autotetraploids and allotetraploids (Figs. 3 & 4). Recent cytogenetic investigations have greatly contributed to the knowledge of the genesis of many European, Mediterranean, Macaronesian and North American species. This lecture deals with the species of some of these genera.

The genus Polypodium is represented in Europe by three species, a diploid, a tetraploid and a hexaploid, the probable interrelationships in them are shown in Fig. 5. The origin of the tetraploid, P. vulgare, is not definitely ascertained, but presumably its parents are two species which do not occur at present in Europe and thus its formation is presumably rather ancient; its centre of origin is uncertain.

The genus Cheilanthes (excl. Notholaena and Cosentinia) is represented in the Mediterranean Region, Europe and Macaronesia by seven species: four diploids and three allotetraploids (Fig. 6). Three other allotetraploids would be theoretically possible, but they are so far unknown. Presumably their formation did not take place since their ranges are geographically far apart from each other. The species of Cheilanthes are regarded as relicts of the xerophilous palaeomediterranean flora. In connection with this subject, the scarcity of strongly xerophilous plants among the Pteridophyta and their scattered occurrence in different families and orders is pointed out.

Asplenium is circumscribed in a narrow sense, and Ceterach, Phyllitis and Pleurosorus are regarded as independent genera. The interrelationships of diploids, hybrids and tetraploids, both auto- and allotetraploids, are shown in Chart 3 which also gives the genomic formulae of the pertinent hybrids, whose names are given in an independent list. The scheme shows also those tetraploids and hybrids which have been synthesized but are not yet found in nature; while those diploids which produce neither hybrids with the other species and between themselves, nor tetraploid progeny are left out. Some observations of various nature pertinent to several species are made in addition to the scheme. Particular attention is paid to the delayed allopolyploidy. This kind of ploidy, in our case an allotetraploidy, is interpreted as an attempt of some species to give a tetraploid progeny, when the hybridization between their diploids is prevented by ecological or chorological barriers, or by a too scarce affinity. An example of the process of formation of delayed allotetraploidy is given in Fig. 7.

The two small satellite genera Ceterach and Phyllitis are able to produce hybrids with Asplenium from which they probably took rise in remote times. One of these intergeneric hybrids is × Asplenoceterach; of which the best known is × A. badense, which is regarded as a delayed allotetraploid (Fig. 7). Other presumed hybrids between these genera are × A. barrancense and × A. newmanii. The latter is not yet cytologically investigated. The intergeneric hybrids between Asplenium and Phyllitis are named × Asplenophyllitis. All of them are triploid and those which have been found in nature are included in a scheme (Fig 8) in which the relationships of their common diploid parent, Phyllitis scolopendrium subsp. scolopendrium with four different tetraploid parents are shown.

Two of the satellite genera of Asplenium, namely Ceterach and Phyllitis, hybridize between themselves as well. Perhaps the plant found recently in Corsica and named Asplenium dutartrei belongs to it. However, Ceterach and Phyllitis are, with certainty, the parents of a very interesting fern endemic to the Quarner islands (Yugoslavia) formerly known as Phyllitis hybrida or Scolopendrium hybridum. It is the sole member of the allotetraploid genus Phyllitopsis, described recently by Reichstein. It has been synthesized under experimental conditions and is originated by hybridization between the diploids Ceterach officinarum subsp. bivalens and Phyllitis sagittata followed by chromosome doubling (Fig. 9). The formation of this genus is particularly interesting since it allows us to presume that a process of this kind might have occurred in other families and thus explaining the origin of some genera in which the base number is tetraploid or even hexaploid or octoploid, in comparison with the diploid base number of most genera of the same family.     

Corticioid fungi from the Kimberley Region,Western Australia

Summary  Corticioid fungi from the Kimberley Region of Western Australia are reviewed. 31 species are reported, of which five, Aleurodiscus kimberleyanus, Athelopsis vesicularis, Dendrothele cornivesiculosa, Hyphoderma tubulicystidium, and Phanerochaete subcrassispora are described as new. Grandinia glauca is given the new combination Grammothele glauca, and Hydnum investiens the new combination Phanerochaete investiens. A further eight species are recorded which have not previously been reported from Australia.     

Biogeography and conservation biology of Florida's Geolycosa wolf spiders: threatened spiders in endangered ecosystems

The state of Florida has a complex biogeography which is the product of past sea level changes and associated ocean currents creating numerous inland sand ridge systems which are home to a unique biota adapted to the seasonally dry conditions found on these sandy uplands. Among these xeric-adapted taxa is a suite of wolf spider species in the genus Geolycosa. Geolycosa wolf spiders are habitat specialists and poor dispersers, and many taxa have ranges restricted to specific ridge systems. We found that the six Geolycosa species typical of Florida's scrubs and sandhills (G. escambiensis Wallace, G. ornatipes (Bryant), G. micanopy Wallace, G. patellonigra Wallace, G. hubbelli Wallace and G. xera McCrone) have current distributions that correlate with the historical biogeography of the state. There are species typical of the Lake Wales Ridge and associated ridges (G. xera and G. hubbelli), species found on the more coastal ridges (G. patellonigra and G. micanopy) and species whose ranges are divided by the Apalachicola River drainage (G. escambiensis and G. ornatipes). We also found that Geolycosa wolf spiders tend to occur in species pairs which use different microhabitats: those which burrow in areas covered in leaf litter, and those which use only barren sites. These latter species require habitat management plans that include burns, that maintain the habitat in an open condition.     

A comparative ultrastructural study of blood cells from nine insect orders

Summary An ultrastructual study of hemocytes from 9 different insect orders has led to the identification of 8 cell types: (1) Plasmatocytes, whose cytoplasm is filled with small dense lysosomes and large heterogeneous structures, are phagocytic cells. (2) Granulocytes, filled with uniformly electron dense granules, are involved in capsule formation. (3) Coagulocytes, which contain granules and structured globules and which possess a well developed RER, are involved in phagocytosis. (4) Spherule cells are filled with large spherical inclusions. (5) Oenocytoids are large cells with few cytoplasmic organelles. These 5 hemocyte types represent the majority of insect blood cells. (6) Prohemocytes, blastic cells which are one of the stem cells of hemocytes, are very few in number in each species investigated. (7) Thrombocytoids and (8) Prodocytes are restricted to a small number of insect species.The ultrastructural characteristics of these hemocyte types are discussed.     

中国腐霉属的水生种类

腐霉属是一个世界广布分类群,迄今为止已报道约100种.它们主要分布于土坡中,条件适合时侵染植物引起病害,造成多种经济植物的重大损失.腐霉也见水中,它们既可寄生于藻类及一些小动物上,也可腐生于动植物残骸上.在研究微生物与水质关系时,腐霉的作用是不可忽视的.在发酵工业上,腐霉可望用于生产多种酶类及转化街族化合物,所以它是一个经济意义较重要的类群.     

Common ancestry between IncN conjugal transfer genes and macromolecular export systems of plant and animal pathogens

The DNA sequence of a cluster of pKM101 conjugal transfer genes was determined and aligned with the genetic map of the plasmid. Eighteen genes were identified, at least eight and probably 11 of which are required for efficient conjugation. These tra genes are homologous to and colinear with genes found in the virB operon of Agrobacterium tumefaciens TI plasmids. Seven pKM101 tra genes are also homologous to ptl genes of Bordetella pertussis, which direct the export of pertussis toxin. We used TnphoA to construct translational fusions between pKM101 genes and the Escherichia coli phoA gene, which encodes alkaline phosphatase, and provide evidence that at least 11 of the 18 genes are either fully or partially exported from the cytoplasm.     

Insertion mutations in the control region of the galactose operon of E. coli. II. Physical characterization of the mutations

Summary Four gal negative mutations, which affect the expression of the gal operon severely as described in the preceding paper (Saedler et al.), are characterized as insertions of DNA by CsCl density gradient centrifugation of transducing phages carrying the mutations and by electron microscopy of hybrid DNA molecules in which the insertion forms a singlestranded loop.Mutation galOP _in 308 is shown by both procedures to be about twice as large as the three other insertions, which are similar in size. The length of the insertions as determined by electron microscopy corresponds to about 1500 nucleotide pairs galOP _in 308 and 800, 700, and 700 nucleotide pairs for galOP _in 128, 141, and 306 respectively. Single-stranded regions are seen in hybrid molecules prepared between DNAs from galOP _in 306 and 128, 141 or 308 as well as from galOP _in 308 and 128. No such single-stranded regions are observed in hybrid molecules between DNAs from galOP _in 128 and 141.Thus, at least three of the four insertions are not identical.     

GENETIC VARIATION AND JUVENILE SURVIVAL IN RED DEER

The survival of red deer (Cervus elaphus L.) calves to two years of age was examined in relation to electrophoretic variation in a population on the Scottish island of Rhum. Survival was analyzed using logistic analysis in which the “phenotypic” factors birth weight, birth date, subdivision of the study area, cohort, and sex, which affect the probability of a calf's survival, were taken into account. All three polymorphic loci examined, Mpi, Idh-2, and Trf (each with two detected alleles) are significantly associated with juvenile survival. At Mpi, there is selection against one allele, f (or an allele at a linked locus), and there are indications that this effect is stronger in females than males. For Idh-2, overall, the heterozygote class survives better than the two homozygotes, which survive equally well. However, again there is a difference between the sexes; female heterozygotes survive much better than homozygotes, whereas male homozygotes survive better than heterozygotes, and the difference in survival is smaller. Furthermore, there is an interaction involving Mpi, Idh-2, and survival in which Mpi^f carriers that are also Idh-2 homozygotes survive very badly compared with other Mpi-Idh-2 combinations, which all survive equally well. For Trf, the heterozygote class survives best, and there is also a difference in survival between the two homozygote classes. Genotype frequencies in the adult population are consistent with the results for calf survival, in that the Mpi^f frequency is lower in succeeding cohorts of surviving adults, whereas no significant gene frequency change is apparent for Idh-2 or Trf.     

Theory of transport in linear biological systems: I. Fundamental integral equation

The conditions under which the output,γ _b (t), of a biological system is related to the input,γ _a (t), by an integral equation of the typeγ _b (t) = ∫ ₀ ^t γ _a (ω)w(t−ω)dω, where ω(t) is a transport functioncharacteristic of the system, are analyzed in detail. Methods of solving this type of integral equation are briefly discussed. The theory is then applied to problems in tracer kinetics in which input and output are sums of exponentials, and explicit formulae, which are applicable whether or not the pool is uniformly mixed, are derived for “turnover time” and “pool” size.     

Initiation of DNA replication in Escherichia coli: RNase H-deficient mutants do not require the dnaA function

Summary A series of temperature-resistant revertants were isolated from strains of Escherichia coli K12 carrying a temperature-sensitive mutation in the dnaA gene. Four independent revertants were found which still carry the original ts mutation. The ability of these strains to grow at high temperature is due to a suppressor mutation, called sin. All four sin mutations are located between the genes metD and proA on the genetic map of E. coli, which suggests that they all affect the same gene. The sin suppressors, which were isolated for their ability to suppress one dnaA mutation, are also able to suppress three other temperature-sensitive dnaA mutations, but they are not able to suppress mutations in either of the two genes dnaB or dnaC. The sin suppressors alone do not confer any particular phenotype on bacteria, but they are deficient in the enzyme RNase H. On the basis of these findings we propose that the function of the dnaA protein is to protect a DNA-RNA hybrid at the origin of replication against RNase H.