Hasel-Pollengehalt der Luft in Mitteleuropa

Jahreszeitliche und tageszeitliche Veränderungen des Haselpollengehalts der Luft nach Untersuchungen aus den Jahren 1967 bis 1972 an elf mitteleuropäischen Meßstellen. Vergleich mit einigen anderen europäischen Daten über den Haselpollengehalt der Luft. In Mitteleuropa kamen die meisten Haselpollen zu Beginn oder gegen Ende des Monats März vor. Stündliche Höchstwerte wurden in den Tag- und Abendstunden gemessen. Morgens kamen keine hohen Stundenwerte vor. Temperaturmessungen lassen vermuten, daß für hohe Haselpollengehalte der Luft in Norddeutschland höhere Temperaturen nötig sind als in südwestdeutschen Gebieten.     

Studies on an Indian polydesmoid millipede Streptogonopus phipsoni Life cycle and swarming behaviour of the larvae

The adults of Streptogonopus phipsoni (Pocock), an Indian polydesmoid millipede, emerge from the soil at the onset of the monsoon and mate. Eggs are laid in the soil and the adults die. The larvae leave the soil at stadium III and, apart from moulting periods, remain on the surface until the end of the monsoon. The larvae are aggregated in swarms, usually consisting of several hundred individuals. They are active on open ground, including metalled roads, during daylight, but usually spend the night in an inactive state under cover of stones or vegetation. If a swarm is disturbed, the individuals scatter but later reaggregate.
Laboratory experiments show that the larvae are sensitive to light even though they lack eyes, and if given a choice spend more time in the light than the dark. Just before and after moulting however they spend more time in the dark than in the light.
Experiments were carried out on the reactions of the larvae to aquatic suspensions of benzaldeyde, since this substance is related to components of the exudate of the repugnatorial glands; strong concentrations (10^-1) repelled the larvae, whilst weak concentrations (10^-6) attracted them. It is suggested that swarms may be dispersed or reaggregated by the effects of variations in concentration of components of the exudates. The benefits to the larvae which may result from swarming are discussed.     

Effect of inhibition of thromboxane production on the leukotriene D4-mediated bronchoconstriction in the guinea pig

Leukotriene D₄ (LTD₄) administered intravenously to anesthetized, spontaneously breathing guinea pigs elicited decreases in dynamic lung compliance (C_dyn) and airway conductance (G_AW) with a maximal response achieved at 0.5 min. Simultaneously, plasma levels of thromboxane metabolite, TxB₂, and the prostacyclin metabolite, 6-keto-PGF_1α, increased 10-fold over pre-LTD₄ levels. Pretreatment of the guinea pigs with meclofenamic acid delayed the onset of the LTD₄-induced bronchoconstriction, antagonized the magnitude of the decreases in C_dyn and G_AW, and blocked the increase in plasma TxB₂ and 6-keto-PGF_1α levels. The thromboxane synthetase inhibitor, UK 37,248, suppressed the LTD₄-induced bronchoconstriction, while it completely blocked TxB₂ production without significantly affecting 6-keto-PGF_1α. The SRS-A end organ antagonist, FPL 55712, blocked both the LTD₄-induced bronchoconstriction and the production of the arachidonic acid metabolites. These results suggest that thromboxane A₂ plays an important role in mediating part of the bronchoconstriction elicited by intravenously administered LTD₄ in the guinea pig.     

The influence of biomass and structure of the crustacean plankton on the water transparency in the Saidenbach storage reservoir

Planktonic crustacean biomass as well as structure are important factors influencing water transparency. The significant dependence of the water quality (Secchi depth) on the concentration and the share of the Daphnia biovolume and not on the total Crustacea biovolume in the Saidenbach reservoir indicates that the density of the Crustacea is only a measure of the cleaning performance, if Daphnia dominates. Using the mean size, the influence of the crustacean structure on the Secchi depth can be recorded. If big size categories prevail (like Daphnia) the water transparency is high. The mainly occurrence of little species (Mesocyclops, Bosmina) results in lower Secchi depths. However, a well defined (significant) relationship is being prevented by the different feeding behaviour of the several species.     

[3H]MK-801 Binding to N-Methyl-d-Aspartate Receptors Solubilized from Rat Brain: Effects of Glycine Site Ligands, Polyamines, Ifenprodil, and Desipramine

The N-methyl-D-aspartate (NMDA) receptor is thought to contain several distinct binding sites that can regulate channel opening. In the present experiments, the effects of ligands for these sites have been examined on [3H]MK-801 binding to a soluble receptor preparation, which had been passed down a gel filtration column to reduce the levels of endogenous small-molecular-weight substances. Glycine site agonists, partial agonists, and antagonists gave effects similar to those observed in membranes [EC50 values (in microM): glycine, 0.31; D-serine, 0.20; D-cycloserine, 1.46; (+)-HA-966, 4.06; and 7-chlorokynurenic acid, 1.81]. Spermine and spermidine enhanced [3H]MK-801 binding to the soluble receptor preparation (EC50, 4.3 and 20.1 microM, respectively), whereas putrescine and cadaverine gave small degrees of inhibitions. When spermine and spermidine were tested under conditions where [3H]MK-801 binding approached equilibrium, their ability to enhance [3H]MK-801 binding was much reduced, a result suggesting that the polyamines increase the rate to equilibrium. Putrescine antagonised the effects of spermine. Ifenprodil reduced [3H]MK-801 binding under both equilibrium and nonequilibrium conditions, although the high-affinity component of inhibition described in membranes was not observed. Ifenprodil antagonised spermine effects in an apparently noncompetitive manner. Desipramine was able to give total inhibition of specific [3H]MK-801 binding under nonequilibrium conditions with an IC50 of 4 microM, and this value was unaltered when [3H]MK-801 binding was allowed to reach equilibrium. These results suggest that the sites mediating the effects of glycine and its analogues, polyamines and desipramine are integral components of the NMDA receptor protein.     

Biochemical and physiological characterization of the efrotomycin fermentation

Summary An efrotomycin fermentation was characterized through physical, chemical and biochemical studies. Growth of the actinomycete,Nocardia lactamdurans occurred during the first 50 h of the fermentation cycle at the expense of glucose, protein, and triglycerides. The initiation of efrotomycin biosynthesis was observed when glucose dropped to a low concentration. Upon glucose depletion, cell growth ceased and a switch in the respiratory quotient occurred. Efrotomycin biosynthesis was supported by the utilization of soybean oil and starch. Analysis of triglyceride metabolism showed that no diglycerides or monoglycerides accumulated during the fermentation. The activity of extracellular enzymes (lipase, protease, and amylase) increase during the cell growth phase and decreased significantly after 150 h. The concentrations of DNA, tetrahydro-vitamin K₂ (a membrane component), and free amino acids in the supernatant increased dramatically late in the fermentation cycle (225 h), indicating massive cell lysis. During this same time period, a reduction in cellular respiratory activity and efrotomycin biosynthesis were observed.