Evolution of nesting strategies of ants: genetic evidence from different population types of Formica ants

Genetic population structure was studied in two types of populations in the ants Formica exsecta and F. pressilabris: populations consisting of single-nest colonies (monodomy) and populations consisting of multi-nest colonies (polydomy). These characteristics seem to be associated with the number of egg-laying females (gynes) in a nest, mating structure of the population, sex ratio and male size variation. The monodomous populations are characterized by single-gyne nests, the population sex ratio is either I:1 or female-biased, males are mainly large-sized, and there is slight inbreeding in the population. The polydomous populations have multi-gyne nests with gynes related to each other, sex ratio is strongly male-biased, most males are small-sized, and there is slight genetic microdifferentiation within the populations. Diploid males found in a polydomous F. pressilabris population suggest that the population is inbred and isolated. Habitat localization is presented as a plausible explanation for the evolution of the polygynous and polydomous population structure.     

Production of second generation triploid and tetraploid rainbow trout by mating tetraploid males and diploid females — Potential of tetraploid fish

Summary First generation tetraploids were produced by hydrostatic pressure treatment before the first cleavage and raised until the adult stage. Their survival and growth were severely depressed when compared to the diploid control: after two years, no ovulated females were found although males produced sperm at 1 and 2 years of age and were mated individually with diploid females. The progenies were consistently normal with high survival rates. They were found to be almost all triploids by karyology, which failed to detect a significant rate of aneuploidies. However, the fertilizing ability of tetraploid males was always low (0 to 97% of the control; average 40%). Several arguments presented here support the hypothesis that diploid spermatozoas, which are wider than haploid ones, would be frequently blocked during their penetration through the micropyle canal. Second generation tetraploids were produced after such matings by heat shocks, causing the retention of the second polar body. Their survival and growth were much more satisfactory than in the first generation, although still lower than in diploid and triploid controls issuing from diploid parents. Performances of second generation triploids were comparable to those of diploids, and slightly better than those of conventional triploids issuing from diploid parents. 94.5% of the second generation tetraploids were male.     

Effects of intravenous epinephrine on macaque platelets

Blood was obtained from three species of macaques for a study of platelets. A rapidly mobilizable platelet pool was demonstrated in rhesus macaques given intravenous epinephrine. The number of platelets/ml of blood increased about 30% 3 to 5 min after epinephrine was given. The size distributions of the platelets were similar before and after injection. Platelet aggregability was increased after injection. Basal platelet aggregabilities, as measured by platelet aggregate ratios, were similar in rhesus macaques. Celebes black macaques, and human subjects, but were significantly greater in cynomolgus macaques than in the other three species.     

Relationship between chloroplast structure and O2 evolution rate of leaf discs in plants from different biotopes in South Finland

Abstract The chloroplast ultrastructure, especially the thylakoid organization, the polypeptide composition of the thylakoid membranes and photosynthetic O₂ evolution rate, chlorophyll (Chl) content and Chi a/b ratio were studied in leaves of nine plants growing in contrasting biotopes in the wild in South Finland. All the measurements were made at the beginning of the period of main growth on leaves approaching full expansion, when the CO₂-saturated O₂ evolution rate (measured at 20°C and 1500 μmol photons m^?2s^?1) was at a maximum, ranging from 19.2 to 6.9 μmol O₂ cm^?2 h^?1. Among the species, the Chi a/b ratio varied between 3.75 and 2.71. In the mesophyll chloroplasts, the ratio of the total length of appressed to non-appressed thylakoid membranes varied between 1.07 and 1.79, the number of partitions per granum varied between 2.8 and 12.0 and the grana area between 21 and 42% of the chloroplast area. There was a significant relationship between the rate of O₂ evolution of the leaf discs and the thylakoid organization in the mesophyll chloroplasts. The higher the O₂ evolution rate, the lower was the ratio of the total length of appressed to non-appressed thylakoid membranes and also the lower the grana area. Although the relationship of the photosynthetic rate with the Chi content and the Chi a/b ratio of the leaves was not as clear, a significant negative correlation existed between the Chi a/b ratio and the ratio of appressed to non-appressed thylakoid membranes, indicating lateral heterogeneity in the distribution of different Chl- protein complexes.     

Statistic evaluation of the influence of species variation,culture conditions,surface wettability and fluid shear on attachment and biofilm development of marine bacteria

A budding coccoid bacterium, (CH1), a Vibrio sp. and a Pseudomonas sp. were investigated for factors governing their attachment to glass surfaces in static batch culture and laminar flow continuous culture systems. An analysis of variance showed that the three species exhibited very different responses. For CH1 attachment was dependent on cell density, incubation time and nutrient concentration. The Vibrio sp. was affected by nutrient concentration while the attachment of the Pseudomonas sp. was independent of cell density, incubation time and nutrient concentration. A comparison of attachment to hydrophilic and hydrophobic surfaces showed that attachment of the Vibrio sp. and CH1 to hydrophilic surfaces was 3 and 10 times greater respectively than to hydrophobic surfaces while Pseudomonas attached in equal numbers to both surfaces. The continuous culture system with defined flow hydrodynamics and growth conditions at steady state revealed a random sampling effect 3 times smaller than the batch culture system did. When the biofilm development of Pseudomonas sp. was followed during 46 h at different fluid shear under laminar and turbulent flow conditions, the former biofilm reached 3.3·10⁸ cells·cm^-2 and the latter 8.2·10⁷ cells·cm^-2.Non-common abbreviation NSS Nine salt solution     

Study on growth and biomass of underground organs ofTypha angustata Bory & Chaub

Underground and aboveground biomass and their ratios at flowering time in different natural stands of Typha angustata near Jaipur, India were studied in the field and experimentally over a period of eleven months (June to April). The underground biomass was 40–50% of the aboveground biomass in both natural and experimental conditions.     

Specific photoperiodic stimulation of dry matter production in a high-latitude cultivar of Poa pratensis

Vegetative plants of Poa pratensis L. cv. Holt (origin 69°N) raised in short days gave large and significant increases in plant dry weight, plant height and leaf area upon exposure to continuous light, compared with 8-h short days, at essentially identical daily inputs of radiant energy (8-h summer daylight ± low intensity extension). For example, by the fourth harvest (after 26, 34 and 46 days at 21, 15 and 9°C, respectively), the dry weights of plants in long days were 81, 163 and 195% greater than those of the corresponding short-day controls at the respective temperatures. Plant leaf areas in long days were between two and four times as large as control values by the end of the experiment. This was mainly due to increased leaf length caused by long-day stimulation of cell extension and division. However, the photoperiod did not affect the partitioning of assimilates amongst leaves, culms and stolons. Most of these effects could also be brought about by exogenous gibberellin application to plants in short days. However, in contrast to the effect of long days, gibberellin treatment also induced stem internode elongation even in these vegetative plants. Examination by standard growth analysis procedures revealed that the observed increases in relative growth rate were due primarily to increased net assimilation rate followed, several days later, by increases in leaf area ratio when newly-emerged leaves began to constitute a significant proportion of the leaf area. It is concluded that these reactions are of great adaptive significance for growth at the marginal temperatures prevailing at high latitudes.     

Enhancement of the repair of carcinogen-induced DNA damage in the hamster pancreas by dietary selenium

We measured single strand breaks (SSB) in pancreas DNA produced by N-nitrosobis(2-oxopropyl)amine (BOP) in hamsters fed purified diets containing added sodium selenite (Se) at 0.0, 0.1 and 5.0 ppm. There were fewer SSB in those given the 5.0 ppm Se diet throughout the experiment. One hour after dosing with BOP (20 mg/kg), there were 2.26 ± 0.47, 2.83 ± 0.43 and 1.74 ± 0.43 SSB per 10⁸ daltons (mean ± S.E.M.) respectively in the three groups. The SSB were repaired faster in the 5.0 ppm Se-fed group. The approximate half-lives of the SSB were 33, 30 and 8 days, respectively. In the hamsters fed 5.0 ppm Se there was a small, statistically significant increase in pancreatic DNA synthesis. Autoradiographic analysis indicated that this was repair synthesis. In a second experiment, hamsters were fed one of the three diets prior to and for 2 days after administration of a single dose of BOP (20 mg/kg). They were then fed the 5.0 ppm Se diet for 5 days. The number of SSB was compared with those in hamsters fed their original diet for 7 days after BOP dosing. There was a statistically significant difference in the number of SSB in the hamsters fed 0.1 ppm Se before and for 2 days after BOP. In these hamsters there were 1.21 ± 0.24 SSB per 10⁸ daltons compared with 3.19 ± 0.4 (mean ± S.E.M.). These results suggest high levels of dietary Se stimulate the repair of carcinogen-induced DNA damage.     

Is male back space limiting? An investigation into the reproductive demography of the giant water bug,Abedus indentatus (Heteroptera: Belostomatidae)

Because male giant water bugs in the subfamily Belostomatinae provide parental care by brooding eggs on their back, an accurate assessment can be made of both the actual and potential reproductive capacity of males. Two operational sex-ratio (OSR) indices were developed and empirically measured for a population of giant water bug, Abedus indentatus,in California. One index was based on reproductive rates measured in the laboratory; the other index was based on reproductive resources observed in the field. Both OSR indices suggest that the operational sex ratio fluctuates between maleskewed ratios in the summer and femaleskewed ratios in the winter. This pattern appears to be the consequence of two factors. First, the adult sex ratio is significantly female biased. Second, although males can outreproduce females at high ambient temperatures, the reverse is true at low temperatures. Possible reasons for the female-skewed adult sex ratio are examined, including differential recruitment, differential mortality, and sampling bias.     

Thiol-dependent passive K:Cl transport in sheep red blood cells: X. A hydroxylamine-oxidation induced K:Cl flux blocked by diethylpyrocarbonate

Summary Hydroxylamine, a potent oxidizing agent used to reverse carbethoxylation of histidine by diethylpyrocarbonate, activated Cl-dependent K flux (KCl cotransport) of low K sheep red blood cells almost sixfold. When KCl cotransport was already stimulated by N-ethylmaleimide, hydroxylamine caused an additional twofold activation suggesting modification of sites different from those thiol alkylated. This conclusion was supported by the finding that hydroxylamine additively augmented also the diamide-induced KCl flux (Lauf, P.K. 1988.J. Membrane Biol. 101:179–188) with dithiothreitol fully reversing the diamide but not the hydroxylamine effect. Stimulation of KCl cotransport by hydroxylamine was completely inhibited by treatment with diethylpyrocarbonate also known to prevent KCl cotransport stimulation by N-ethylmaleimide, both effects being independent of the order of addition. Hence, although the effect of carbethoxy modification on KCl flux cannot be reversed by hydroxylamine and thus excludes histidine as the target for diethylpyrocarbonate, our finding reveals an important chemical determinant of KCl cotransport stimulation by both hydroxylamine oxidation and thiol group alkylation.