Dynamics of chemiluminescence response of Syrian hamster blood neutrophils to the growth of 10 different strains of tumor cells]

The production of H2O2 by blood neutrophils of Syrian hamsters, bearing 10 different transplanted tumors was studied at different stages of tumor growth by the luminol-dependent chemiluminescence (CL) test. It was demonstrated that during the tumors growth, two types of the blood neutrophils CL reaction can be registered. The first type of reaction represents very early and significant decrease of spontaneous CL of blood neutrophils, already evident before the appearance of palpable tumor nodules in animals, bearing in vivo selected cell strains. Subsequent subcutaneous tumor appearance in the animals was followed by increased CL of neutrophils. The second type of reaction was characteristic for in vitro transformed cells never selected in vivo. In this case the increase of CL of blood neutrophils at early stages of tumor growth was followed with the decrease of this activity at the period of active tumor growth. Possible relation of this reactions to the survival and growth of different tumor cells in vivo is discussed.     

Effects of organic fluorosilicone compounds on the development of tumors in mice

The influence of new synthesized fluoro-silicium-organic complexes on the virus-induced Rauscher leukosis and cell-transferred MX-11 mouse sarcoma was studied. We also studied the cytotoxic effects of these complexes in vitro in the human CaOv cells. Two complexes from seven studied were cytotoxic for CaOv cells. Five complexes from seven studied diminished the mortality of animals with MX-11 tumors on the 27-th day of observation, but the total life duration of the animals in the experimental group was the same as in controls. One complex from seven studied increased the life duration of mice with MX-11 tumors. No effects were noted in relation to mice virus-induced Rauscher leukosis.     

The prickly pear (Opuntia ficus-indica [Cactaceae]) in South Africa: Utilization of the naturalized weed,and of the cultivated plants

In spite of successful biological control efforts, vast areas of South Africa remain infested with the spiny prickly pear weed, Opuntia ficus-indica. These remnant populations, which vary from sparse to dense and which are more or less stable, are confined mainly to the eastern Cape. They provide a popular fruit and a limited source of income for certain sectors of the population in these areas. In terms of existing legislation, there are, however, restrictions on the large-scale utilization of these fruit. A novel method for mass-rearing the cochineal insect, Dactylopius coccus, for the commercial production of a red dye (carminic acid) has been developed. The cultivated spineless prickly pear has recently been enjoying renewed attention from researchers and growers alike. Whereas it has traditionally been cultivated mainly as a droughtresistant fodder crop, and is still popular as such, it is now increasingly recognised as a fruit, in its own right, with considerable promise as a commercial crop for local and export markets. There is also a need to encourage the use of very young cladodes (nopalitos) as a highly nutritious vegetable for human consumption in South Africa.     

Combined use of extraction and genetic engineering for protein purification: recovery of beta-galactosidase fused proteins.

Partitioning of beta-galactosidase in aqueous two-phase systems of poly(ethylene glycol) and potassium phosphate is reviewed. The affinity of Escherichia coli beta-galactosidase for the PEG-rich phase dominates also in beta-galactosidase fusion proteins and the concept of using beta-galactosidase as an affinity handle for extraction of other proteins, after fusion, is discussed. A hypothesis is presented, assuming that tryptophan residues at the surface of beta-galactosidase is responsible for its partitioning to the PEG rich phase, and the concept of poly-tryptophan handles fused to the target protein for extraction is introduced.     

The Force-Frequency Dependence in the Heart Papillary Muscle of Ground Squirrel as a Reflection of Changes in the Functional State of Animals during the Annual Cycle

Biophysics - Abstract—A study was conducted to explore the characteristics of the dependence of the contraction force (isometric mode at 30°C) on the frequency of stimulation...     

Comparative phylogeography of two co‐distributed but ecologically distinct rainbowfishes of far‐northern Australia

Aim

To test the influence of historical and contemporary environment in shaping the genetic diversity of freshwater fauna we contrast genetic structure in two co‐distributed, but ecologically distinct, rainbowfish; a habitat generalist (Melanotaenia splendida) and a habitat specialist (M. trifasciata).

Location

Fishes were sampled from far northern Australia (Queensland and Northern Territory).

Methods

We used sequence data from one mitochondrial gene and one nuclear gene to investigate patterns of genetic diversity in M. splendida and M. trifasciata to determine how differences in habitat preference and historical changes in drainage boundaries affected patterns of connectivity.

Results

Melanotaenia splendida showed high levels of genetic diversity and little population structure across its range. In contrast, M. trifasciata showed high levels of population structure. Whereas phylogeographic patterns differed, both species showed a strong relationship between geographical distance and genetic differentiation between populations. Melanotaenia splendida showed a shallower relationship with geographical distance, and genetic differentiation was best explained by stream length and a lower scaled ocean distance (11.98 times coast length). For M. trifasciata, genetic differentiation was best explained by overwater distance between catchments and ocean distance scaled at 1.16 × 10⁶ times coast length.

Main conclusions

Connectivity of freshwater populations inhabiting regions periodically interconnected during glacial periods appears to have been affected by ecological differences between species. Species‐specific differences are epitomized here by the contrast between co‐distributed congeners with different habitat requirements: for the habitat generalist, M. splendida, there was evidence for greater historical genetic connectivity with oceans as a weaker barrier to gene exchange in contrast with the habitat specialist, M. trifasciata.     

Effect of overproduction of heat shock chaperones GroESL and DnaK on human procollagenase production in Escherichia coli.

The effect of overexpression of the heat shock chaperone genes dnaK and groESL on heterologous protein production in Escherichia coli was examined, using a set of related human procollagenase proteins. A diverse range of effects on protein solubility, secretion, and accumulation was observed, and these effects were highly dependent on the particular chaperone/procollagenase pairing involved. Both chaperones caused a large increase in the apparent solubility of a fusion of the LamB signal peptide to procollagenase. GroESL had no effect on the accumulation of mature (secreted) procollagenase, while DnaK suppressed secretion considerably. In the absence of a signal peptide, overexpression of either chaperone resulted in a dramatic increase in both solubility and accumulation of procollagenase. The 10-fold increase in accumulation was associated with an increase in in vivo protein half-life.