Microdistribution of chironomids (Diptera: Chironomidae) in Alpine streams: an autoecological perspective

Chironomid communities from three glacial and three non-glacial high mountain streams in three Alpine river basins were analyzed (Conca, Niscli, Cornisello, NE Italy, 46°N, 10°E). Eighteen sampling reaches belonging to five stream types (kryal, subkryal, glacio-rhithral, kreno-rhithral, outlet) were investigated. At each reach, geomorphological, physical, chemical and biological data were collected. Field surveys were carried out during three periods per year from 1996 to 1998: immediately after spring snowmelt, in mid-summer and in early autumn. In all, 439 zoobenthos samples were collected from 5 to 10 microhabitats of 0.1m² in each reach and date using a standard pond net (mesh size of 250m). About 50% of individuals collected were chironomids (26673 specimens, 53 taxa), with densities ranging from 4 to 2652indm^–2. With few exceptions, they dominated as number of taxa and individuals in all reaches. Chironomid subfamilies Diamesinae and Orthocladiinae were most abundant, especially in glacial reaches, where Diamesa spp. constituted up to 100% of the total fauna. Chironomid distribution was analyzed in relation to 37 abiotic variables, referring to stream origin, hydrology, geomorphology, physics and chemistry. Diamesa steinboecki, D. latitarsis gr. A and Pseudokiefferiella parva were the taxa best associated with glacial conditions (i.e. high channel instability or presence of bedrock, high suspended solids and total phosphorous content, low conductivity and silica content, highly variable diel discharge and low mean temperature), while Pseudodiamesa branickii, Corynoneura spp., Eukiefferiella spp., Parorthocladius nudipennis, Tvetenia calvescens/bavarica, Thienemaniella spp. and Micropsectra atrofasciata were mostly associated with non-glacial conditions. Substratum particle size, water depth, current velocity, the presence of riffles/pools and of mosses/algae (Hydrurus foetidus) were the major factors affecting microdistribution of chironomids in the investigated streams.     

Formation ofα,ω-dodecanedioic acid andα,ω-tridecanedioic acid from different substrates by immobilized cells of a mutant ofCandida tropicalis

Summary The metabolic formation of either,-dodecanedioic acid or,-tridecanedioic acid from the individual n-alkane, n-alcohol, n-monoacid and,-diol with corresponding carbon chain length using K-carrageenan entrapped mutants S76 ofCandida tropicalis was studied. The immobilized cells of S76 could also directly produce-hydroxy acid and,-dioic acid from,-diol. With n-alcohol and n-monoacid as substrate, the amount of-hydroxy acid and,-dioic acid produced was also a function of the incubation time.The results demonstrated that in the immobilized cells of S76 the formation of,-dioic acid from n-alcohol can also run both via n-monoacid and via,-diol as well as in the normal cells of S76.     

The origin of Q-independent derivatives of phage lambda

Summary qsr (Q-independent) phages are characterised by the replacement of the region of the genome that contains Q, S, R, and the late gene promoter, P_R, with host-derived DNA that codes for functions analogous to those deleted. Restriction endonuclease analysis and DNA/DNA hybridisation methods have been used to show that p4 and qin A 3, two such Q-independent phages, are the product of recombination between and a defective lambdoid prophage (the qsr prophage) located at an as yet unidentified site in the E. coli K 12 chromosome. The qsr prophage is distinct from the defective lambdoid prophage Rac (Kaiser and Murray 1979). In the E. coli K 12 strain AB1157 from which qsr phages cannot be generated, the qsr prophage has suffered an internal deletion. That the qsr prophage appears not to carry a full complement of essential late genes suggests one explanation for its apparently defective nature.     

Virulence ofPythium spp. isolated from pond water

Pre-emergence damping-off tests indicate that Pythiumspp. from pond water can be divided into two categories: avirulent Pythium (P. diclinum, P. marsipium, P. middletonii, P. monospermum, P. pleroticum, P. undulatum)and weakly virulent Pythium (P. catenulatum, P. coloratum, P. dissotocum, P. papillatum, Pythium Group F, Pythium group HS, Pythium group P, Pythiumgroup T). Post-emergence damping-off tests indicate that the pythia tested can also be divided into three categories: avirulent Pythium (P. catenulatum, P. dissotocum, P. marsipium, P. monospermum, P, papillatum, P. pleroticum, P. undulatum, Pythium group F, Pythium group T),weakly virulent Pythium (P. coloratum, P. diclinum, P. middletonii, Pythiumgroup P and moderately virulent Pythium (Pythium group HS).     

Sources and inheritance of resistance to leaf curl virus in Lycopersicon

Summary One hundred and twenty-two varieties, lines and wild accessions of Lycopersicon were screened under three different regimes during the autumn/winter season of 1982–83 and 1983–84 for resistance to tomato leaf curl virus (TLCV). L. hirsutum f. glabratum (B6013) and L. hirsutum f. typicum (A1904) proved to be highly resistant to TLCV in all three environments. Various accessions of L. peruvianum were also highly resistant. L. pimpinellifolium (A1921) exhibited no TLCV symptoms within 90 days. Of the cultivated varieties, Acc 99 exhibited the minimim score for susceptibility; AC 142, Collection No. 2, Kalyanpur Angurlata and HS 101 had a low rating for virus incidence. The inheritance of resistance was studied in the interspecific crosses between a TLCV resistant line of L. pimpinellifolium (A1921) and five (HS 101, HS 102, HS 110, Pusa Ruby and Punjab Chhuhara) susceptible cultivars of L. esculentum. Parents, F₁, F₂ and backcross progenies were artificially inoculated with local strains of TLCV using vector the viruliferious whitefly, Bemisia tabaci (Genn.). Data indicated that the resistance of L. pimpinellifolium (A 1921) is monogenic and incompletely dominant over susceptibility.     

Regioselective preparation of 2′, 3′-di-O-acylribonucleosides carrying lipophilic acyl groups through a lipase-catalysed alcoholysis

Candida antarctica B lipase-catalysed alcoholysis of 2, 3, 5-tri-O-hexanoyluridine (1a), 2, 3, 5-tri-O-dodecanoyluridine (1b), 2, 3, 5-tri-O-hexanoylinosine (1c) and 2, 3, 5-tri-O-dodecanoylinosine (1d) proceeded regioselectively to produce the corresponding 2, 3-di-O-acylribonucleosides 2a–d, providing a simple and efficient access to these new lipophilic compounds. Contrasting to the alcoholysis, enzymatic hydrolysis of 1a–d using different enzymes and experimental conditions did not proceed regioselectively.     

Inheritance and linkage of isozyme loci in almond

The segregation of seven isozyme marker genes was investigated using eight controlled crosses in almond. The cultivar Nonpareil was the maternal parent in all crosses. Pollination was achieved using eight different cultivars, and a total of 3200 individual kernels were assessed. For each isozyme the goodness-of-fit test was used to test for departure from the expected frequencies assuming Mendelian inheritance. Given a higher than expected number of significant results for individual isozymes, independent segregation between pairs of isozymes was tested using the chi-square statistic on the resulting two-way contingency tables. In all crosses a highly significant association (P value< 0.001) was observed between (1) the AAT- 1 and IDH isozymes loci and (2) the LAP-1 and PGM-2 isozymes loci, which leads to the conclusion that the respective isozyme pairs are linked.In addition, a significant association (P value < 0.001) was observed between LAP-1 and GPI-2 when the pollen sources were Fritz, Mission, or Price, but this could not be tested for the remaining five pollen sources, Carmel, Grant, Keane, Ne plus Ultra, Peerless, because they are homozygous at these loci. If LAP-1 is linked with GPI-2 and PGM-2, it might be expected that we should find evidence of linkage between GPI-2 and PGM-2. The lack of a significant association between these two isozymes suggests that LAP-1 is located centrally on the chromosome. These three pairs of linked loci are the first to be reported in almond.     

Distance-constraint approach to protein folding. I. Statistical analysis of protein conformations in terms of distances between residues

A statistical analysis of protein conformations in terms of the distance between residues, represented by their C atoms, is presented. We consider four factors that contribute to the determination of the distanced _i,i+k between a given pair ofith and(i+k)th residues in the native conformation of a globular protein: (1) the distancek along the chain, (2) the size of the protein, (3) the conformational states of theith to(i+k)th residues, and (4) the amino acid types of the and(i+k)th residues. In order to account for the dependence on the distancek along the chain, the statistics are taken for three ranges, viz., short, medium, and long ranges (k8; 9k20; andk21; respectively). In the statistics of short-range distances, a mean distanceD _k and its standard deviationS _k are calculated for each value ofk, with and without taking into account the conformational states of all residues fromi toi+k (factors 1 and 3). As an Appendix, the relations for converting from the distances between residues into other conformational parameters are discussed. In the statistics of long-range distances, a reduced distanced* _ij (the actual distance divided by the radius of gyration) is used to scale the data so that they become independent of protein size, and then a mean reduced distanceD _l (a, a) and its standard deviation _l (a, a) are calculated for each amino acid pair (a, a) (factors 2 and 4). The effect of the neighboring residues along the chain on the value of the distanced* _ij is explored by a linear regression analysis between the actual reduced distanced* _ij and the mean value over theD _l for all possible pairs of residues in the two segments of the (i–2)th to the (i+2)th and the (j–2)th to the (j+2)th residues. The effect is assessed in terms of the tangentA _l (a, a) of the calculated regression line for each amino acid pair (a, a). In the statistics of medium-range distances, only factors 1 and 4 are considered, to simplify the analysis. The scaled distanced _i,i+k =(d _i,i+k -D _k )/S _k is used to eliminate the dependence onk, the distance along the chain. The propertiesD _m (a, a), _m (a, a) andA _m (a, a) corresponding toD _l (a, a), _l (a, a), andA _l (a, a), and also calculated for each amino acid pair (a, a). The results are interpreted as follows: the smaller values ofD _l (a, a) andD _m (a, a) indicate a preference of the pair (a, a) for a contact (e.g., pairs between hydrophobic amino acids, and pairs of Cys with aromatic amino acids), and the larger values of these quantities indicate a preference for distant mutual location (e.g., pairs between strong hydrophilic amino acids); the smaller values of _l (a, a) and _m (a, a) indicate a strong preference for either contact or noncontact (e.g., pairs between hydrophobic amino acids, and pairs between strong hydrophobic and hydrophilic amino acids, respectively), and the larger values of these quantities indicate the ambivalent/neutral nature of the preference for contact and noncontact (e.g., pairs containing Ser or Thr); the smaller values ofA _l (a, a) andA _m (a, a) indicate that the distance of an (a, a) pair is determined independently of the amino acid character of the neighboring residues along the chain (e.g., some pairs of Cys or Met with other amino acids) and the larger values of these quantities indicare that such amino acid character contributes strongly to the determination of the distance (e.g., pairs containing Ser or Thr, and pairs between amino acids with small side chains). The difference between the statistics for the long- and medium-range distances is also discussed; the former reflect the difference between the hydrophobic and hydrophilic character of the residues, but the latter cannot be easily interpretable only in terms of hydrophobicity and hydrophilicity. The data analyzed here are used in the optimization of an object function to compute protein conformation in a subsequent paper.     

Nucellar callus of ‘Femminello’ lemon,selected for tolerance toPhoma tracheiphila toxin,shows enhanced release of chitinase and glucanase into the culture medium

Phoma tracheiphila is the causative agent of the disease mal secco. Citrus cultivars differ substantially in respect to their sensitivity to the pathogenP. tracheiphila and its toxin. Some cultivars (e.g., Femminello lemon) are inherently sensitive while others (e.g., Tarocco orange) are tolerant. Cell lines derived from nucellar tissue of Femminello, Tarocco and a cell line selected for tolerance to the fungal toxin (Femminello-S) were used to study host-pathogen interaction. Our results showed that calli or conditioned media of Tarocco and Femminello-S inhibited the size of co-cultivated fungal colonies when compared to Femminello. In addition, conditioned medium of Tarocco as well as FemminelloS, but not Femminello, promoted bursting of hyphal tips. A ten-fold increase in chitinase and glucanase enzymatic activity, as evaluated by radiometric assay and laminarin hydrolysis respectively, was detected in Femminello-S extracellular extracts as compared to Femminello. An increase in chitinase was also shown by immunoblot analysis. Our findings suggest a positive correlation between the presence of chitinase and glucanase in the conditioned media of the cultured cells and the tolerance of those cells toP. tracheiphila toxin.     

The assignment of a Thinopyrum distichum (Thunb.) Löve-derived translocation to the long arm of wheat chromosome 7D using endopeptidase polymorphisms

Summary Endopeptidase zymograms of the translocation line Indis revealed the presence of several major and minor bands that had differential expression in coleoptile and seed tissues. While Indis lacks Ep-D1a, which is present in the parental cultivar Inia 66, it also may not express any of the Th. distichum bands. The Indis zymogram was found to be identical to that of an isogenic line of Inia 66 possessing Lr19. Since the absence of an Ep-D1a product appears to be linked to the 7DL translocation, it is possible to use the null condition as a marker for both the Lr19 or Indis translocations. The Indis translocation also did not show recombination with the cn-D1 chlorophyl mutant on 7DL, confirming that a part of 7D was involved. The results of a telocentric mapping experiment involving the 7D telosomes indicated that in Indis a chromosome segment from Th. distichum replaced a large section of 7DL of Inia 66.     

Natural 15N abundance in shrub and tree legumes,Casuarina, and non N2 fixing plants in Thailand

The leaves and nodules from the shrub and tree legumes, particularly, Aeschynomene spp., Sesbania spp., Mimosa spp. and Leucaena spp., and Casuarina spp. and the leaves from neighbouring non-fixing plants were analyzed for their natural abundances of ¹⁵N ( ¹⁵N).The ¹⁵N in the leaves of non-fixing plants was +5.9% on average, whereas those from shrub legumes and Casuarina spp. were lower and close to the values of atmospheric N₂, suggesting the large contribution of N₂ fixation as the N source in these plants. The ¹⁵N values of the leaves from tree legumes except for Leucaena spp. were between the shrub legumes and non-fixing plants, which suggests that the fractional contribution of fixed N₂ in tree legumes may be smaller than that in the shrub legumes. Casuarina spp. was highly dependent on N₂ fixation. The ¹⁵N values of the nodules from most of the shrub legumes investigated were higher than those of the leaves.     

Transformation of 16-dehydroprogesterone and 17α-hydroxyprogesterone by Mucor piriformis

Mucor piriformis was used to study the mode of transformation of 16-dehydroprogesterone (I, pregna-4, 16-diene-3, 20-dione) and 17-hydroxyprogesterone (II, 17-hydroxypregn-4-ene-3, 20-dione). Biotransformation products formed from I were 14-hydroxypregna-4, 16-diene-3, 20-dione (Ia), 7, 14-dihydroxypregna-4, 16-diene-3, 20-dione (Ib), 3, 7, 14-trihydroxy-5-pregn-16-en-20-one (Ic), and 3, 7, 14-trihydroxy-5-pregn-16-en-20-one (Id). Metabolites Ic and Id appear to be hitherto unknown. Time-course studies suggested that the transformation is initiated by hydroxylation at the 14-position (Ia) followed by hydroxylation at the 7-position (Ib). Microsomes (105,000 g sediment) prepared from 16-dehydroprogesterone-induced cells hydroxylate I to its 14-hydroxy derivative (Ia) in the presence of NADPH. Incubation of Ia with the organism resulted in the formation of Ib, Ic and Id. Biotransformation products formed from compound II were 17, 20-dihydroxypregn-4-en-3-one (IIa), 7, 17-dihydroxypregn-4-ene-3, 20-dione (IIb), 6, 17, 20-trihydroxypregn-4-en-3-one (IIc) and 11, 17, 20-trihydroxypregn-4-en-3-one (IId). Time-course studies indicated that IIa is the initial product formed, which is further hydroxylated either at the 6 or 11 position. Incubation of IIa with the organism resulted in the formation of IIc and IId. Reduction of the 4-en-3-one system and 20-keto group has not been observed before in organisms of the order Mucorales. In addition, M. piriformis has been shown to carry out hydroxylation at the C-6, C-7, C-11 and C-14 positions in the steroid molecules tested.     

Diversity of benthic macrofauna in the eastern English Channel: comparison among and within communities

The diversity of benthic macrofaunal assemblages in the eastern English Channel is described from 707 samples collected with a Rallier-du-Baty dredge during 1971–1975. Four assemblages were primarily defined by means of multivariate data analyses and clustering methods: the Abra alba community, the Ophelia borealis community, the pebbles community and a mixed assemblage of the first three communities. Spatial heterogeneity of these communities is significantly correlated with sedimentary characteristics, although local variability appears to be controlled by both physical and biological processes. Ecological diversity of these communities was analysed considering species richness (S), the Shannon diversity index (H), and rank-frequency diagrammes (RFD). These analyses were performed at two spatial scales: for a single sample, and for a 'site of 10 pooled samples. Thus, several sites were chosen in order to compare diversity patterns and species quantitative structure among and within the communities. The greatest species richness was recorded for the pebbles (57–69) and the A. alba (63–79) communities. In the former, high values may be due to the complexity of microhabitats and the large flux of food related to strong currents. In the latter, both organic matter and terrestrial inputs associated with the mud favour the presence of deposit-feeder organisms. No clear trend was observed among and within the community sites in terms of the species quantitative structure. Thus, convex RFD shapes were observed in three assemblages: the mixed assemblage (offshore site), the A. alba (North Sea), and the pebbles (Normandy coast). Sigmoid shapes were observed in the pebbles (Dover Strait) and A. alba (English coast) communities. Presumably, these shapes can be caused by the combined action of physical (strong currents, substrate stability, mud content in the sediments) and biological factors (co-occurrence of species from different communities, strong species recruitment, relative dominance of carnivorous species).     

Horizontal Gene Transfer of “Prototype” Nramp in Bacteria

Eukaryotic Nramp genes encode divalent metal ion permeases important for nutrition and resistance to microbial infection. Bacterial homologs encode proton-dependent transporters of manganese (MntH), and other divalent metal ions. Bacterial MntH were classified in three homology groups (A, B, C) and MntH C further subdivided in C, C, C. The proteins from C. tepidum (MntH B) and E. faecalis (MntH C1, 2), divergent in sequence and hydropathy profile, conferred increased metal sensitivity when expressed in E. coli, suggesting conservation of divalent metal transport function in MntH B and C. Several genomic evidence suggest horizontal gene transfer (HGT) of mntH C genes: (i) The enterobacteria Wigglesworthia mntH C gene is linked to an Asn t-RNA, and its sequence most conserved with Gram positive bacteria homologs; (ii) all the C genes identified in oral streptococcaceae are associated with different potentially mobile DNA elements; (iii) Lactococcus lactis and Burkholderia mallei genomes contain an mntH gene prematurely terminated and a novel full-length mntH C gene; (iv) remarkable sequence relatedness between the unicellular alga C. reinhardtii prototype Nramp and some MntH C (e.g., Nostoc spp., Listeria spp.) suggests HGT between Eukarya and Bacteria. Other prototype Nramp genes (intronless, encoding proteins strongly conserved with MntH A and B proteins) identified in invertebrates represent a possible source for transfer of Nramp genes toward opportunistic bacteria. This study demonstrates complex evolution of MntH in Bacteria. It is proposed that prototype Nramp are ancestors of bacterial MntH C proteins, which could facilitate bacterial infection. Equally contributing authors (Etienne Richer and Pascal Courville).     

Linear differentiation of cereal chromosomes

Summary The BSG test was used in a comparative study of the linear chromosome differentiation and the idiograms of T. Macha ssp. tubalicum v. letschchumicum Dek. et Men., T. georgicum Dek., T. timopheevi. Zhuk., T. carthlicum Nevski, T. dicoccum Schrank, v. rufum, T. durum Desf. v. Arnautka were compiled.The karyotype of each polyploid wheat species consists of two groups of chromosomes. The first is formed by ten pairs of constant chromosomes occurring almost in all species and the second by all the rest of the variable chromosomes that are either fully specific for the species in question or occur only in a few species. T. timopheevi largely differs from other species of polyploid wheats in the high level and specific localization of structural heterochromatin on chromosomes. The rols of introgression in wheat evolution and the necessity of establishing a General Cytological Nomenclature of Cereal Chromosomes are discussed.     

Oscillations in density and diversity ofPisidium communities in two biotopes in Southern Poland

Summary From September 1979 to October 1980 in two types of biotopes (in the stream at Kali and in the Biaa Przemsza River near Jaroszowiec, southern Poland)P.amnicum, P.milium, P.subtruncatum, P.nitidum, P.personatum, P.casertanum andP. sp.non det. were found.P.amnicum was accepted as an indicator species for the river community, andP.milium for the stream. The irregular changes of species composition of the sphaeriid community in the stream at Kali are rather accidental and the only temporary occurrence ofP.nitidum, P.personatum andP. sp.non det. in the Biaa Przemsza River might be connected with seasonal migration.The dominance structure of thePisidium community in the stream agrees with the model described by CONNELL (1977) for the communities of large sedentary animals and plants. The dominance relations in the river community are similar to the situation described by CONNELL (1977) as characteristic for small lakes and islands.The density of the Sphaeriidae on the chosen habitat in the Biaa Przemsza River oscillated between 300 and 3.300 ind./m² and it reached almost 130.000 ind./m² in the stream at Kali.The SHANNON-WIENER's diversity index (H) and that of equitability or evenness of species abundances (J) had low values during the whole period of investigation.This study was performed as part of the Problem MRII/15 of the Polish Academy of Sciences.     

Attraction of the bark beetle Tomicus piniperda and some other bark- and wood-living beetles to the host volatiles α-pinene and ethanol

The attraction of some bark- and ambrosia beetles as well as associated beetles to the host volatiles -pinene and ethanol was studied in field tests with flight barrier traps. Tomicus piniperda (L.) (Scolytidae), Thanasimus formicarius (L.) (Cleridae), and Rhizophagus ferrugineus (Payk.) (Rhizophagidae) were attracted by -pinene, while Hylurgops palliatus (Gyll.) and Trypodendron lineatum (Oliv.) (Scolytidae) were attracted by ethanol and Epuraea spp. (Nitidulidae) by both -pinene and ethanol. Combinations of -pinene and ethanol attracted high numbers of H. palliatus, T. lineatum, R. ferrugineus, Epuraea spp., and Glischrochilus spp. (Nitidulidae) and the catches increased with increasing release rates of ethanol. By contrast, lower numbers of T. piniperda were caught in traps baited with combinations of -pinene and ethanol than in traps baited with -pinene alone, and the catches of this species decreased with increasing release rates of ethanol. Traps baited with a combination of -pinene and ethanol or with -pinene alone caught similar numbers of T. formicarius. The results are discussed on the basis of species differences in preference for breeding substrate.

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Zusammenfassung Die Anlockung mehrerer Borkenkäfer und assoziierter Käferarten zu den flüchtigen Wirtsstoffen -Pinen und Äthanol wurde in Feldversuchen mit Flugbarrierenfallen studiert. Tomicus piniperda (L.) (Scolytidae), Thanasimus formicarius (L.) (Cleridae) und Rhizophagus ferrugineus (Payk.) (Rhizophagidae) wurden durch -Pinen angelockt, die Borkenkäfer Hylurgops palliatus (Gyll.) und Trypodendron lineatum (Oliv.) durch Äthanol und die Epuraea-Arten (Nitidulidae) durch sowohl -Pinen als auch Äthanol.Kombinationen von -Pinen und Äthanol lockten viele Individen von H. palliatus, T. lineatum, R. ferrugineus, Epuraea spp. und Glischrochilus spp. (Nitidulidae) an, und die Fänge nahmen mit zunehmender Äthanol-Abgabe zu. Umgekehrt wurden weniger T. piniperda in Fallen mit Kombinationen von -Pinen und Äthanol gefangen als in Fallen mit -Pinen allein, und die Waldgärtner-Fänge nahmen mit zunehmender Äthanol-Abgabe ab. Die Fänge von T. formicarius in Fallen mit einer Kombination von -Pinen und Äthanol unterschieden sich nicht von denen in Fallen mit nur -Pinen.Die Ergebnisse werden auf der Grundlage der Unterschiede zwischen den Arten in der Wahl des Brut-substrats besprochen.

     

Zoogeography and the predator-prey ‘arms race:’ A comparison of eriphia and nerita species from three faunal regions

We measured maximum shell diameters and thicknesses of Nerita funiculata Menke and N. scabricosta Lamarck (Gastropoda: Neritidae), and claw sizes and carapace widths of the predatory crab Eriphia squamata Stimpson (Brachyura: Xanthidae), from the Gulf of California (Eastern Pacific). We also tested the ability of E. squamata to crush Nerita shells of various sizes. We compared this data on predator-prey counteradaptations with previously published data for congeneric species from the Western Atlantic and Indo-West Pacific regions. In relative abilities of the crabs to crush gastropod shells, and of the gastropod shells to resist such crushing, the Eastern Pacific species were stronger than their counterparts in the Western Atlantic, but weaker than their Indo-West Pacific congeners, indicative of an intermediate level of faunal dominance or predator-prey arms race escalation.     

Chromosomal location of esterase,peroxidase and phosphoglucomutase isozyme structural genes in cultivated rye (Secale cereale L.)

Summary Isoelectric focusing of esterase (EST), peroxidase (PRX), and phosphoglucomutase (PGM) isozymes in Chinese Spring wheat, Imperial rye and several Chinese Spring/Imperial and Holdfast/King II addition, translocation and substitution lines revealed the chromosomal location of nine Est loci previously described and of one Prx and Pgm locus. Loci Est1, Est2, Est3, Est5, Est6 and Est7 were found on chromosome arm 5RL, Est8 and Est9 on chromosome 6R in Imperial rye, and the Est10 locus on chromosome arm 4RL in Imperial rye and King II rye. A discrepancy was found between the chromosomal location of the Prx locus in Imperial where chromosome 2R was responsible for the expression of the peroxidase enzyme, and King II with chromosome 1R carrying the Prx gene. As a possible explanation, the occurrence of translocation events during the production of wheat/rye aneuploid lines is discussed. The rye Pgm locus could be associated with chromosome 4RS in Imperial and King II rye. Except for the location of Est loci on chromosome 5RL, the results reported in this paper lend further evidence for the assumed homoeology relationships between the chromosomes of Triticinae and for the conservation of gene synteny groups during the evolution of the Triticeae tribe.     

Facile synthesis of 2′-substituted lactoses

Isopropylidenation of lactose with 2,2-dimethoxypropane in the presence ofp-toluenesulfonic acid gave two products, which were identified by¹H- and¹³C-NMR as 2,35,63,4-tri-O-isopropylidenelactose dimethyl acetal (1) and its 6-O-(2-methoxy)-isopropyl derivative (2). These products were used for the synthesis of 2-O-methyllactose (7), 2,6-di-O-methyllactose (9) and 2-O-benzyllactose (13).