Chromosomal polymorphisms involving telomere fusion,centromeric inactivation and centromere shift in the ant Myrmecia (pilosula) n=1

Detailed karyological surveys of the ant Myrmecia pilosula species group, which is characterized by the lowest chromosome number in higher organisms (2n=2), were attempted. We revealed that this species has developed highly complicated chromosomal polymorphisms. Their chromosome numbers are in the range 2n=2, 3, and 4, and six polymorphic chromosomes are involved, i.e., two for chromosome 1 (denoted as SM₁ and ST₁), three for chromosome 2 (A₂, A₂, and M₂), and M₍₁₊₂₎ for the 2n=2 karyotype. We suggested that these chromosomes were induced from a pseudo-acrocentric (A ₁ ^M ) and A₂ as follows: (1) A ₁ ^M SM₁ or ST₁ by two independent pericentric inversions; (2) A₂A₂M₂ by chromosomal gap insertion and centromere shift; and (3) ST₁+A₂M₍₁₊₂₎ by telomere fusion, where (3) means that the 2n=2 karyotype was derived secondarily from a 2n=4 karyotype. It is a noteworthy finding that active nucleolus organizer (NOR) sites, in terms of silver staining, are tightly linked with the centromere in this species, and that both the centromere and NOR of A₂ were inactivated after the telomere fusion.     

Reproductive isolation between the two forms ofPanonychus akitanus Ehara (Acarina: Tetranychidae)

Crossing experiments were carried out between the stiped-egg form collected from Sapporo (43°04N) and Machida (35°33N), and the stipeless-egg form ofPanonychus akitanus Ehara from Tomakomai (42°37N) and Imagane (42°34N). Intra-form crosses gave a high proportion of female progeny, but inter-form crosses only male progeny, suggesting that fertilization did not take place. The number of eggs laid during the first 10 days of the oviposition period was greater in intra-form crosses than in inter-form crosses (P<0.001). The latter, except for the cross between the Sapporo and the Imagane populations, had similar egg production to virgin females (P<0.05).Mated females showed a greater daily oviposition rate than virgin females. However, the latter drastically increased their oviposition rate after mating with their sons. The two forms are thus reproductively isolated.     

The molecular basis of HbH disease in Taiwan

Summary We have determined the molecular characteristics of -thalassemia in 12 HbH subjects from Taiwan by restriction endonuclease mapping with -and -specific probes. We have found four types of defects in the -thalassemia-2 genetic determinant: ^3.7 type I; ^4.2; ^CS; and ^T. All HbH subjects carried the ——^SEA genotype in the -thalassemia-1 determinant. At least two different subtypes of ——^SEA genotype were observed in this study.     

Ammonium sorption to channel and riparian sediments: A transient storage pool for dissolved inorganic nitrogen

Sediment (0.5 mm–2.0 mm grain size) was incubated in nylon bags (200 m mesh) below the water table in the channel and in two transects of shallow wells perpendicular to the banks (to 18 m) of a third-order stream during August, 1987. One transect of wells drained steep old-growth forest, and the other a steep 23 year-old clear-cut partially regenerated in alder. At approximately 6-week intervals between October, 1987, and June, 1988, bags were retrieved. Total exchangeable ammonium was determined on sediment, and dissolved oxygen, nitrate and ammonium were determined in stream and well water. Exchangeable ammonium ranged from 10 eq/100 g of sediment in the stream where nitrification potential and subsurface exchange with stream water were high, to 115 eq/100 g sediment 18 m inland where channel water-groundwater mixing and nitrification potential were both low. Sorbed ammonium was highest during summer/autumn base flow and lowest during winter storm flow. Both channel and well water contained measurable dissolved oxygen at all times. Ammonium concentration was typically < 10 g-N/L in channel water, increased with distance inland, but did not exceed 365 g-N/L at any site. Nitrate concentration was typically higher in well water than channel water. Nitrate levels increased dramatically in wells at the base of the clear-cut following the onset of autumn rains. The results indicate a potential for temporary storage of ammonium on riparian sediments which may influence biotic nitrogen cycling, and alter the timing and form of dissolved inorganic nitrogen transport from the watershed.     

Water stress-induced oxidative damage and antioxidant responses in micropropagated banana plantlets

Oxidative injury and antioxidant responses were investigated in two banana genotypes (Musa AAA Berangan and Musa AA Mas) subjected to 40 % PEG-induced water stress. PEG treatment resulted in oxidative injury, as expressed in increased lipid peroxidation and reduced membrane stability index, in both cultivars; however, greater oxidative injury was detected in Mas. Under PEG treatment, catalase activity and glutathione reductase activity were enhanced in both cultivars, but were higher in Mas. Ascorbate peroxidase activity was enhanced in Berangan under water stress, but was unaffected in Mas. Meanwhile, superoxide dismutase activity was inhibited in both cultivars under water stress, but higher activity was detected in Berangan. Higher ascorbate peroxidase and superoxide dismutase activities were associated with greater protection against water stress-induced oxidative injury.     

The distribution of short chain carboxylic acids in eutrophic drainage channels

The concentration of the C₂–C₅ carboxylic acids in the water column and sediment of shallow, eutrophic, drainage channels (Lewes Brooks, UK) were measured by gas chromatography. The concentrations of these acids were negatively correlated with dissolved oxygen. The highest concentrations of acetate (up to 200 M), propanoate (up to 38 M) and butanoate (up to 1.2 M) were measured during the summer in the water above the sediment, which became hypoxic during this period. Both acetate and propanoate concentrations declined at night. High concentrations of the acids were also recorded in reedbeds, which were also hypoxic. Only acetate was detected in the sediment pore water (up to 168 M). Its concentration declined during the autumn and winter and with increasing depth within the sediment.Author for Correspondence     

Hydrogen isotope discrimination in higher plants: Correlations with photosynthetic pathway and environment

Summary The ratio of deuterium to hydrogen (expressed as D) in hydrogen released as water during the combustion of dried plant material was examined. The D value (metabolic hydrogen) determined on plant materials grown under controlled conditions is correlated with pathways of photosynthetic carbon metabolism. C₃ plants show mean D values of-132 for shoots and -117 for roots; C₄ plants show mean D values of -91 for shoots and-77 for roots and CAM plants a D value of-75 for roots and shoots. The difference between the D value of shoot material from C₃ and C₄ plants was confirmed in species growing under a range of glasshouse conditions. This difference in D value between C₃ and C₄ species does not appear to be due to differences in the D value (tissue water) in the plants as a result of physical fractionation of hydrogen isotopes during transpiration. In C₃ and C₄ plants the hydrogen isotope discrimination is in the same direction as the carbon isotope discrimination and factors contributing to the difference in D values are discussed. In CAM plants grown in the laboratory or collected from the field D values range from-75 to +50 and are correlated with ¹³C values. When deprived of water, the D value (metabolic hydrogen) in both soluble and insoluble material in leaves of Kalanchoe daigremontiana Hamet et Perr., becomes less negative. These changes may reflect the deuterium enrichment of tissue water during transpiration, or in field conditions, may reflect the different D value of available water in areas of increasing aridity. Whatever the origin of the variable D value in CAM plants, this parameter may be a useful index of the water relations of these plants under natural conditions.     

Primary structure of hemoglobin β-chain fromColumba livia (gray wild pigeon)

Primary structure of -chain of pigeon is presented. It was determined by amino acid sequence analysis of intact -chain and its peptides obtained by the enzymatic and chemical cleavage. Comparison of amino acid sequence of the chain with other available data shows 14 Ile, 61 Lys, and 113 Ile as residues specific to pigeon. One important replacement at ₁₁ contact is 55 MetSer.     

Ganglioside-cholera toxin interactions: a binding and lipid monolayer study

Summary On t.l.c. plates ¹²⁵I-cholera toxin binds to a disialoganglioside tentatively identified as GD_lb with about 10 times less capacity than to ganglioside GM₁. Binding of labeled toxin to both gangliosides was abolished in presence of excess amounts of unlabeled B subunit. Ganglioside extracts from human or pig intestinal mucosa showed toxin binding to gangliosides GM₁ and GD_1b. In ganglioside-containing lipid monolayers the penetration of the toxin was independent of the ganglioside binding capacity.Abbreviations GM₂ Gal-NAc14Gal(3-2NeuAc)14G1c1Cer - GM₁ Gal3Ga1-NAc14Gal(32NeuAc)14G1c11Cer - GD_1a NeuAc23Ga113Gal-NAc14Gal(32NeuAc)14G1c11Cer - GD1b Gall3Gal-NAcl4Gal(32NeuAc82NeuAc)14Glc11Cer - GT_1b NeuAc23Ga113Ga1-NAcal4Gal(3-2NeuAc82NeuAc)14G1c11Cer - dpPC 1,2-hexadecanoyl-sn-glycero-3-phosphocholine - dpPE 1,2-hexadecanoyl-sn-glycero-3-phosphoethanolamine     

The Biogeochemical Cycle of Methane on the Northwestern Shelf of the Black Sea

Seasonal investigations of methane distribution and rates of its oxidation and generation in the water column and sediments of the Black Sea northwestern shelf were carried out within the framework of the interdisciplinary projects European River–Ocean Systems (EROS-2000, EROS-21) and Biogenic Gases Exchange in the Black Sea (BigBlack) in August 1995, May 1997, and December 1999. Experiments that involved the addition of ¹⁴CH₃COONa and ¹⁴CO₂ to sediment samples showed the main part of methane to be formed from CO₂. Maximum values of methane production (up to 559 mol/(m² day)) were found in coastal sediments in summer time. In winter and spring, methane production in the same sediments did not exceed 3.6–4.2 mol/(m² day). The ¹³C values of methane ranged from –70.7 to –81.8, demonstrating its microbial origin and contradicting the concept of the migration of methane from cold seeps or from the oil fields located on the Black Sea shelf. Experiments that involved the addition of ¹⁴CH₄ to water and sediment samples showed that a considerable part of methane is oxidized in the upper horizons of bottom sediments and in the water column. Nevertheless, it was found that, in summer, part of the methane (from 6.8 to 320 mol/(m² day)) arrives in the atmosphere.     

A ‘minimum stress inflexion’ in relation to environmental and biotic influences on the dynamics of subtidal encrusting communities?

The sedentary fauna of sublittoral boulders was studied at five sites with very different environmental conditions within Lough Hyne Marine Nature Reserve (51° 30 N, 9° 18 W). The degree of competition was assessed through the construction of competitive hierarchies built up from the results of nearly 3000 interactions between organisms. Communities at all sites were predominantly hierarchically organised with few stand-offs recorded. Density of interactions was correlated with total space occupation. Flow speed at all sites was logged over 24 h and this factor also correlated with space occupation. Degree of disturbance was assessed through the use of marked boulders at each site. Species diversity peaked where all factors were moderate and was lowest at extreme sites. The effects of these environmental variables and biotic factors in determining community composition are discussed, and a working model detailing a Minimum Stress Inflexion is described. This represents an extension of the intermediate disturbance hypothesis in that it is proposed that disturbance in this system may serve to reduce sediment load as opposed to preventing space monopolisation in the classical model.     

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.     

Effects of mine drainage on the river hayle,cornwall a) factors affecting concentrations of copper,zinc and iron in water,sediments and dominant invertebrate fauna

Concentrations of copper, zinc and iron were measured in waters, sediments and invertebrates collected from the River Hayle. In river water at least 70% of copper and iron was associated with the particulate fraction whereas 80% of zinc was in the soluble form. Although total concentrations of zinc in water exceeded those of copper approximately ten fold, copper predominated over zinc in the sediments by a factor of approximately three. Iron was the most abundant metal recorded in both water and sediments.Seasonal differences in total metal content of waters suggested that concentrations of copper, zinc and iron increased during. periods of high flow and decreased during lower flows. Copper concentrations in the sediment, unlike zinc and iron, showed markedly higher values during the summer sampling period when flows were minimal.In the free-living Trichoptera larvae, concentrations of copper and zinc in the tissue appeared to follow copper and zinc levels in the water. Similar relationships in Odonata and Plecoptera larvae were not obtained. Factors affecting animal/metal relationships are discussed with particular reference to adaptation shown by organisms exposed to high concentrations of heavy metals in their environment.Department of Applied Biology, Cambridge     

Effects of sulfate concentration in the overlying water on sulfate reduction and sulfur storage in lake sediments

We investigated the effects of sulfate concentration on sulfate reduction and net S storage in lake sediments using³⁴S as a tracer. The water overlying intact sediment cores from the hypolimnion of Mares Pond, MA, was replaced with two Na₂ ³⁴SO₄ solutions at either ambient (70 M) or elevated (260 M) sulfate concentrations. The ³⁴S of the added sulfate was 4974 . Over two months, the net sulfate reduction rate in the ambient sulfate treatment was zero, while the net rate for the high sulfate treatment was 140 moles/m²/d. The water overlying the cores was kept under oxic conditions and the sediment received no fresh carbon inputs, thus the net rate reported may underestimate the in situ rate. Gross sulfate reduction rates calculated by isotope dilution were approximately 350 moles/m²/d for both treatments. While the calculation of gross sulfate reduction rates in intact sediment cores can be complicated by differential diffusion of³⁴S and³²S, isotopic fractionation, and the possible formation of ester sulfates, we believe these effects to be small. The results suggest that sulfate reduction is not strongly sulfate-limited in Mares Pond. The difference in net sulfate reduction rates between treatments resulted from a decrease in sulfide oxidation and suggests the importance of reoxidation in controlling net S storage in lake sediments. In both treatments the CRS and organic S fractions were measurably labelled in³⁴S. Below the sediment surface, the CRS fraction was the more heavily labelled storage product for reduced sulfides.     

Kinetics of Δψ-Dependent Sucrose Transport in Plasma Membrane Vesicles from Higher Plant Cells

The inside-out vesicles of plasma membranes were isolated from pumpkin stem cells, and the kinetics of sucrose efflux induced by the K⁺-diffusion potential (_D) was studied by measuring light transmission. Two phases differing in their rates and duration were identified in _D-dependent changes of light transmission. The increase in _Delevated the rate and magnitude of the fast phase in light transmission changes but did not markedly affect the rate of the slow phase. These two phases also differed in their sensitivity to inhibitors and to changes in sucrose concentration in the external medium. Measurements of _Dduring sucrose transport by means of the fluorescence probe dis-C₃-(5) revealed differences in the magnitude of _Dand its stability in vesicles loaded with sucrose and mannitol, as well as under the action of inhibitors. The two-phase dependence of sucrose efflux from vesicles on the applied diffusion potential is discussed in the context of modern concepts on the functioning of sucrose carriers in the membranes.     

Characterization of chromosomes with hybrid genes for Hb Lepore-Washington,Hb Lepore-Baltimore,Hb P-Nilotic,and Hb Kenya

Summary This study concerns the characterization of chromosomes with hybrid genes for Hb Lepore-Washington (44 chromosomes), for Hb Lepore-Baltimore (5 chromosomes), for Hb P-Nilotic (8 chromosomes), and for Hb Kenya (7 chromosomes) by determining a relatively large number of restriction enzyme polymorphism. Two, and possibly three, different Hb Lepore-Washington chromosomes were identified by specific haplotypes, while the haplotype of the Hb Lepore-Baltimore chromosome had its own characteristic pattern. A likely conclusion is that the crossovers leading to the formation of these chromosomes have occurred as independent events within the populations. Chromosomes with the -Lepore-Washington hybrid gene maintained specific characteristies (such as increased Hb F levels in heterozygotes, and high or low ^G values in this Hb F) which have been observed in normal individuals with chromosomes having comparable haplotypes. Only one haplotype was observed for each of the chromosomes carrying either the -P-Nilotic hybrid gene or the ^A hybrid gene of Hb Kenya.     

Heritable variation in the phaseolin protein of nondomesticated common bean,Phaseolus vulgaris L.

Summary Crude protein extracts from single seeds of nondomesticated Mexican bean accessions were analysed by SDS polyacrylamide gel electrophoresis for variability in phaseolin protein. Six new phaseolin types; M1, M2, M3, M4, M5, M6, which contained polypeptides within the same range of molecular weights (51,000 to 45,000 daltons) as occur in the S, T and C phaseolin types of cultivated beans were identified. No T and C types were found among the non-domesticated Mexican accessions, and the S type occurred in less than 7% of the seeds screened. Genetic analyses of F₂ progenies from crosses between Sanilac (S), and five of the M types showed that each M phaseolin phenotype was allelic to the S type and expressed codominantly.     

Recent history of Lake Ladoga

Combined paleolimnological investigations of a 1.8 m sediment core from the deepest north-western part of Lake Ladoga show stratigraphic changes in granulometric and chemical composition, organic matter content, diatom species composition and chlorophyll a concentration. The sediment accumulation rate was calculated and 5 stages of lake history over the last 4 000 years were described. Changes in lake environment were mainly caused by changes in climate and lake water balance. Human impact on the lake was also traced.     

Adoptions expérimentales de larves entre des fourmis de genres différents (II):Myrmica laevinodis Nylander etAnergates atratulus Schenck

Résumé Nous avons fait élever des larves d'Anergates atratulus par des ouvrières deMyrmica laevinodis à 22°C. Pour y parvenir, il n'est pas utile de faire hivernerensemble les larves d'Anergates et les ouvrières deMyrmica. La présence de larves autochtones n'empêche pas lesMyrmica d'élever des larves d'Anergates. Dans toutes les expériences lesMyrmica ont été soumises au fridavant de recevoir des larves d'Anergates. Aucune reine deMyrmica n'a été utilisée dans ces expériences.Sur les 64 larves d'Anergates que nous avons utilisées, 38 se sont transformées en imagos. C'est au début de l'adoption et au moment des métamorphoses que périrent la plupart des 26Anergates perdus. Les femelles vécurent en général 2 ou 3 jours et cherchèrent très tôt à quitter le nid natal. Les mâles vécurent 2 à 3 semaines.

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Summary Larvae ofAnergates atratulus were experimentally reared by workers ofMyrmica laevinodis, at 22°C. An overwintering of both larvae ofAnergates and workers ofMyrmica is not necessary for the success of that experiment. The presence of larvae ofMyrmica does not keep theMyrmica from rearing larvae ofAnergates. The workers ofMyrmica have been cooled, in all the experiments, before receiving larvae ofAnergates. No queen ofMyrmica have been used in that experiments.38 of the 64 larvae ofAnergates used became imagos. Most of the 26 lostAnergates died at the beginning of the adoption and during the metamorphosis. The females lived generally 2 or 3 days and tried, very early, to leave their native nest. The males lived 2 or 3 weeks.

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Anergates atratulus Myrmica laevinodis, 22 . bmecme Anergates Myrmica. Myrmica Anergates. Myrmica Anergates. Myrmica . 64 Anergates , 38 . 26 Anergates 2 3 . 2 3 .

     

Regulators of cell division in plant tissues. XVI

Summary [³H]Zeatin was supplied through the transpiration stream to radish (Raphanus sativus L.) seedlings with roots excised. Formation of dihydrozeatin was not detected but numerous other metabolites were formed, including adenine, adenosine, AMP, zeatin riboside and zeatin riboside-5-monophosphate. However, in labelled seedlings which had been left in water for 15 h, an unknown compound (raphanatin) was the dominant metabolite and accounted for about 25% of the total radioactivity extracted. A procedure for the isolation of this metabolite was devised and yielded 70 g from 1600 seedlings. Raphanatin was characterized by mass and ultraviolet spectra and has been identified as 7-glucosylzeatin. It is an active and very stable metabolite which was located mainly in the cotyledon laminae and may be a storage form of the hormone. In contrast, labelled nucleotides, the other major metabolites of zeatin, were largely confined to the hypocotyls and petioles. Zeatin riboside-5-monophosphate was the dominant metabolite in hypocotyls of de-rooted seedlings supplied with zeatin for 0.5–2 h. The majority of the radioactivity in the xylem sap was due to zeatin, but about 10% was present as zeatin riboside; nucleotides accounted for less than 10% of the radioactivity and labelled raphanatin was not detected.For Part XV, see Letham (1973).