Three-dimensional organization of actin cytoskeleton and podosomal contact structures in neoplastic cells in vitro

In spontaneously metastasizing rat RPS sarcoma cells, a 3D structure of oblique F-actin cables was observed which was associated with active cell migration in vitro. This led us to further comparative investigations of several other neoplastic and normal cell populations in vitro for F-actin structures using confocal laser scanning microscopy (CLSM). Various forms of F-actin cytoskeleton were observed and the incidence of podosome-related contact structures appeared to be associated with malignancy, interpreted as metastatic capacity.     

Smaller muscle ATP reduction in women than in men by repeated bouts of sprint exercise.

It was hypothesized that the reduction of high-energy phosphates in muscle after repeated sprints is smaller in women than in men. Fifteen healthy and physically active women and men with an average age of 25 yr (range of 19-42 yr) performed three 30-s cycle sprints (Wingate test) with 20 min of rest between sprints. Repeated blood and muscle samples were obtained. Freeze-dried pooled muscle fibers of types I and II were analyzed for high-energy phosphates and their breakdown products and for glycogen. Accumulation of plasma ATP breakdown products, plasma catecholamines, and blood lactate, as well as glycogen reduction in type I fibers, was all lower in women than in men during sprint exercise. Repeated sprints induced smaller reduction of ATP and smaller accumulation of IMP and inosine in women than in men in type II muscle fibers, with no gender differences in changes of ATP and its breakdown products during the bouts of exercise themselves. This indicates that the smaller ATP reduction in women than in men during repeated sprints was created during recovery periods between the sprint exercises and that women possess a faster recovery of ATP via reamination of IMP during these recovery periods.     

Effects of frost hardening on the composition of galactolipids and phospholipids occurring during isolation of chloroplast thylakoids from needles of scots pine

Frost hardening of seedlings of Scots pine (Pinus sylvestris) at a non-freezing temperature of 4°C resulted in a 2-fold increase of the acyl lipids of the needles. This was because of increases in phospholipids and triglycerides. The galactolipid content of the needles was almost the same in unhardened and frost-hardened seedlings. In unhardened seedlings the mol ratio of monogalactosyl diacylglycerol (MGDG) to digalactosyl diacylglycerol (DGDG) was 1.7 ± 0.3 and 0.9 ± 0.2 in needles and isolated thylakoids, respectively. Corresponding ratios for frost-hardened seedlings were 1.5 ± 0.2 and 0.3 ± 0.03. The lower ratios found in isolated thylakoids, particularly in thylakoids from frost-hardened seedlings, are suggested to depend on the enzyme galactolipid: galactolipid galactosyltransferase being active during the isolation procedure. This is deduced from the result that the content of MGDG decreased and that of DGDG and 1.2 diglycerides increased. Needles of Scots pine also contain phospholipidase D. This enzyme was active during thylakoid preparation, particularly after frost hardening, as judged from the large amount of phosphatidic acid found the in thylakoid fraction isolated from frost-hardening needles. The fatty acid composition of the acyl lipids showed no major changes due to hardening at non-freezing temperature.     

Local and regional assessments of the impacts of plant invaders on vegetation structure and soil properties of Mediterranean islands

Aims Although biological invasions occur throughout the world, and some invaders are widespread in many habitats, few studies on the ecological impact of invaders have examined multiple sites. We tested how the impact of three widespread plant invaders changed depending on the identity of the species and the invaded island. We also tested whether relative species loss was lower in species‐rich communities than in species‐poor ones. Location We conducted floristic surveys and soil analyses in eight Mediterranean Basin islands: Crete and Lesbos (Greece), Sardinia (Italy), Corsica, Bagaud and Porquerolles (France), and Mallorca and Menorca (Spain). Methods We compared native species richness and diversity, proportion of life forms, soil percentage nitrogen, percentage organic carbon, C/N, and soil pH in nearby paired plots of 2 × 2 m: one control and one invaded by either the deciduous tree Ailanthus altissima, the succulent subshrubs Carpobrotus spp. or the annual geophyte Oxalis pes‐caprae, across eight Mediterranean Basin islands. Results On average, the presence of invaders reduced species diversity, Carpobrotus spp. exhibiting the largest impact and Oxalis the least. However, the relative impact was island‐dependent, and was positively but weakly associated with the species richness of the recipient community. Therophytes were the life form that experienced the largest decrease across islands. The effects of invasion on soil properties were very variable. Total N changed (increased) only in plots invaded by Ailanthus, significantly decreasing the C/N ratio. The presence of this tree increased soil pH, whereas the opposite was found in plots invaded by the other two species. Organic C increased in plots invaded by Ailanthus and Carpobrotus species. Main conclusions By conducting an analysis at multiple sites, we found that the three plant invaders had an impact on plant community structure not entirely concordant with changes in soil properties. The impacts depended on the identity of the species and of the invaded island, suggesting that impact of invaders is context‐specific. The impact in terms of species loss was not lower in species‐rich than in species‐poor communities.     

Sensitive detection of transglycosylating activity of xyloglucan endotransglycosylase/hydrolase (XTH) after isoelectric focusing in polyacrylamide gels.

The paper describes a sensitive and rapid zymogram technique for detection of transglycosylating activity (XET) of xyloglucan endotransglycosylase/hydrolase (XTH; EC 2.4.1.207) in polyacrylamide isoelectric focusing gels. After the electrophoresis, the separating gel was overlaid and incubated with an agarose detection gel containing XET substrates: tamarind-seed xyloglucan as the glycosyl donor and sulphorhodamine-labeled xyloglucan-derived oligosaccharides (XGO-SRs) as the glycosyl acceptors. The transglycosylation catalyzed by XTH caused incorporation of the fluorescent label into the high-M(r) polysaccharide. Selective removal of unreacted XGO-SRs from the agarose replicas by washing with organic solvents revealed the zones corresponding to XET activity as bright pink fluorescent spots under UV-light. The method appears suitable for a number of purposes such as analysis of the isoenzyme composition of XTHs with XET activity in crude extracts from various plants and plant organs, monitoring the enzyme expression at various stages of plant development and/or for checking enzyme purity in the course of its isolation procedure.     

Trapping sand flies (Diptera: Psychodidae) in the Emilia-Romagna region of northern Italy.

The efficiency and practicality of two trapping methods for adult Phlebotomine sand flies in two areas of the Emilia-Romagna region (Italy) were evaluated. Suction traps (CO2) and sticky traps (ST) were used to collect sand flies every two weeks, from June to September, 1999, from 16:00 to 07:00. Two CO2 traps were activated at the same time for each area (one with light and one without light), whereas 38 (four with light and 34 without lights) and 48 (four with light and 44 without) sticky traps were activated in Borghi and Longiano, respectively. An Index of Apparent Abundance (IAA) was calculated for each trap type and area. A total of 2,253 sand flies was trapped over the four-month period, with 1,765 collected from Borghi and 488 from Longiano. Phlebotomus perfiliewi was the most abundant species collected, comprising 99.6% and 84.6% of the total flies trapped in Borghi and Longiano, respectively. Other species were also collected within the two areas (Phlebotomus perniciosus and Phlebotomus mascittii) but were not considered for further analyses due to low catches. Significantly more specimens were caught using CO2 than sticky traps and the addition of a light source also improved the catches, however, a significantly greater number of female specimens were collected by a CO2 trap without a light source. Phlebotomus perfiliewi thus appears to show a photophobic reaction in the case of females when trapped using CO2/light attractants.     

Pyruvate metabolism in germinating seeds during natural anaerobiosis

Lactate as well as ethanol is formed in seeds of soybean, maize, pea, bean, lentil and broad-bean in the course of germination during the so-called natural anaerobiosis. After 0 to 30 h of germination a concentration peak of lactate appears. Maximum in ethanol content is found after 40 h. The amount of ethanol is higher big more than one order of magnitude as compared to the amount of lactate. Both products of anaerobiosis occur in germinating seeds irrespective of the type of reserve substances. In contrast to alcohol dehydrogenase lactate dehydrogenase (EC 1. 1. 1. 27) is present in the dry seeds too. Its activity decreases during the first 12 h of germination. It is in this stage that its substrate, lactate, is usually present at a maximal concentration. During the later stages of germination the amount of lactate decreases and enzyme activity rises. There exists a reciprocal relationship between enzyme activity and substrate concentration. In the case of alcohol dehydrogenases (EC 1. 1. 1. 1) the maximum concentration of ethanol precedes the peak of enzyme activity.     

In Vitro and In Vivo Studies of Streptomycin-Dependent Cholera Vibrios

Streptomycin-dependent cholera vibrio strains were derived from Inaba, Ogawa, and NAG vibrios by the method of Mel. These phenotypes grew more slowly and attacked fermentable substances after a longer period of time than the streptomycin-sensitive parent strains. Rabbits injected with streptomycin-sensitive strains and their streptomycin-dependent forms showed homologous agglutinin production. Patas monkeys fed with 10(9) streptomycin-dependent strains shed them for 1 to 2 days without ill effect, whereas the same number of streptomycin-independent organisms caused disease. The possibility of the application of multiple doses of streptomycin-dependent organisms in oral immunization against cholera was considered.