DDT-lipoprotein complex in the American cockroach hemolymph: A possible way of insecticide transport

The binding in vitro of ¹⁴C-DDT to proteins from the hemolymph of the American cockroach was shown by means of electrophoresis and isoelectric focusing on polyacrylamide gels. The study of ¹⁴C-DDT penetration into the insect implies the hemolymph as one of the possible manners by which this insecticide could penetrate the central nervous system, and other target organs. The possibility of DDT being transported by the hemolymph bound to lipoproteins is discussed.     

A New Type of Lysimeter

Two lysimeters are described. One has most of the weight of the soil container supported by its buoyancy in water, while the remaining weight is supported by a flexible water-filled bag on which it rests. The other has the whole of the weight of the soil container supported by the water-filled bag. In both instruments changes in weight of the soil container are measured as changes in water pressure in the bag.

The lysimeters respond readily to weight changes equivalent to o -oi in. of water on an area equal to that of the surface of the contained soil, and variations due to temperature changes can easily be allowed for.

The apparatus is simple and easy to build, free from the danger of leaks, and transportable. The components used are cheap and readily available, so that it is practicable to install a number of instruments for adequate replication in detailed studies of water use by crops under a variety of conditions. This has not usually been possible with existing lysimeter installations, mainly because of their cost.     

Dead wood in European beech (Fagus sylvatica) forest reserves

Data were analysed on the volume of dead wood in 86 beech forest reserves, covering most of the range of European beech forests. The mean volume was 130 m³/ha and the variation among reserves was high, ranging from almost nil to 550 m³/ha. The volume depended significantly on forest type, age since reserve establishment and volume of living wood. More dead wood was found in montane (rather than lowland/submontane) reserves, longer-established reserves (time since designation) and reserves with higher volumes of living wood.

On average, fallen dead wood contributed more to the total dead wood volume than standing dead wood. The percentage of dead wood that was standing was almost twice as high in montane than in lowland/submontane forest reserves (45% versus 25%). The volume of dead wood at selected sites changed considerably over time. The fluctuations were significantly higher in lowland/submontane than montane reserves, possibly connected with differences in the disturbance regimes and especially damage caused by windstorms. In NW Europe, the blow down of formerly managed, even-aged stands led to extraordinary high volumes of dead wood shortly after reserve establishment.

The implications for forest management and biodiversity conservation are discussed. An increase in dead wood volumes must be carried out in accordance with the local/regional forest type and disturbance regime. Thus, in order to fulfil the requirements of as many wood-depending organisms as possible, it is important to preserve not only larger amounts of dead wood, but also dead wood of different types and dimensions as well as securing a long-term continuity of dead wood.     

Effects of feed particle size at dietary presence of added organic acids on caecal parameters and the prevalence of Salmonella in fattening pigs on farm and at slaughter

In a field study with fattening pigs, effects of feed particle size at the dietary presence of organic acids on Salmonella prevalence were measured. On two farms (f1/f2), each holding ～800 pigs, diets based on finely ground (control) or coarsely ground ingredients (experiment) were fed as crumbs. On f1 both control and experimental grower and finisher diets contained identical concentrations of formic and propionic acid (0.4% and 0.2% respectively). On f2 only finisher diet of the experimental group contained 1.2% potassium diformate. At the start of the fattening period no statistical differences were measured between Salmonella prevalence in animals fed control and experimental diets on both farms. At slaughter Salmonella prevalence in caecal contents was lower (p < 0.05) on f1 in animals fed the experimental diet. Furthermore, the number of seronegative meat juice samples taken from these animals [optical density (OD) <10] was higher (p < 0.001); seropositive as well as distinct seropositive samples (OD ≥20 and ≥40 respectively) were less frequent (p < 0.01) compared to samples from animals fed the control diet. Feeding the experimental diet on f2 resulted in a lower Salmonella detection rate in faeces before slaughter (p < 0.01). Salmonella prevalence was lower in caecal content at slaughter for pigs fed the experimental diet compared to those fed control diet (p < 0.0001). The number of distinct seropositive meat juice samples (OD ≥40) was lower (p < 0.01) for pigs fed the experimental than for those fed the control diet. In comparison to pigs in the control group, starch concentrations in the caecal content from pigs in the experimental groups on both farms were higher (p < 0.05) and the pH values lower (p < 0.05). Propionate (p < 0.0001) and butyrate (p < 0.01) concentrations were higher in the caecal content taken from pigs in the experimental group on f2.     

Effect of egg turning and incubation time on carbonic anhydrase gene expression in the blastoderm of the Japanese quail (Coturnix c. japonica)

1. The gene expression of carbonic anhydrase, a key enzyme for the production of sub-embryonic fluid (SEF), was assessed in turned and unturned eggs of the Japanese quail. The plasma membrane-associated isoforms CA IV, CA IX, CA XII, CA XIV, and the cytoplasmic isoform CA II, were investigated in the extra-embryonic tissue of the blastoderm and in embryonic blood. 2. Eggs were incubated at 37.6 degrees C, c.60% RH, and turned hourly (90 degrees ) or left unturned. From 48 to 96 h of incubation mRNA was extracted from blastoderm tissue, reverse-transcribed to cDNA and quantified by real-time qPCR using gene-specific primers. Blood collected at 96 h was processed identically. 3. Blastoderm CA IV gene expression increased with the period of incubation only in turned eggs, with maxima at 84 and 96 h of incubation. Only very low levels were found in blood. 4. Blastoderm CA II gene expression was greatest at 48 and 54 h of incubation, subsequently declining to much lower levels and unaffected by turning. Blood CA II gene expression was about 25-fold greater than in the blastoderm. 5. The expression of CA IX in the blastoderm was the highest of all isoforms, yet unaffected by turning. CA XII did not amplify and CA XIV was present at unquantifiable low levels. 6. It is concluded that only gene expression for CA IV is sensitive to egg turning, and that increased CA IV gene expression could account for the additional SEF mass found at 84 to 96 h of incubation in embryos of turned eggs.     

Movement of Road Salt to a Small New Hampshire Lake

Runoff of road salt from an interstate highway in New Hampshire has led to contamination of a lake and a stream that flows into the lake, in spite of the construction of a diversion berm to divert road salt runoff out of the lake drainage basin. Chloride concentration in the stream has increased by over an order of magnitude during the 23 yr since the highway was opened, and chloride concentration in the lake has tripled. Road salt moves to the lake primarily via the contaminated stream, which provides 53% of all the chloride to the lake and only 3% of the total streamflow to the lake. The stream receives discharge of salty water from leakage through the diversion berm. Uncontaminated ground water dilutes the stream downstream of the berm. However, reversals of gradient during summer months, likely caused by transpiration from deciduous trees, result in flow of contaminated stream water into the adjacent ground water along the lowest 40-m reach of the stream. This contaminated ground water then discharges into the lake along a 70-m-wide segment of lake shore. Road salt is pervasive in the bedrock between the highway and the lake, but was not detected at all of the wells in the glacial overburden. Of the 500 m of shoreline that could receive discharge of saly ground water directly from the highway, only a 50-m-long segment appears to be contaminated.