Decreased atrial natriuretic factor receptors and impaired cGMP generation in glomeruli from the cardiomyopathic hamster

To determine a possible basis for the decreased action of atrial natriuretic factors (ANF) in congestive heart failure, we compared the cardiomyopathic hamster (CMH) in frank congestive failure, and the age-matched, normal, F1B strain of Golden Syrian Hamsters. Scatchard analysis of competitive binding studies revealed two classes of glomerular receptors. The CMH exhibited decreased binding overall and a markedly decreased number of high affinity receptors but comparable receptor affinity compared to the F1B. In contrast, the low affinity receptor population in the CMH had a much greater affinity compared to the F1B while receptor number was similar. Plasma ANF levels were substantially elevated in the CMH compared to the F1B and in-vitro generation of cGMP was significantly lower in the CMH. Such abnormalities could contribute to the resistance to ANF in this disease.     

Storage of pollen grains of Crotalaria retusa in oils

Summary Attempts were made to store pollen grains of Crotalaria retusa L. in a mineral oil (paraffin oil) and two vegetable oils (soybean oil and olive oil). Under laboratory conditions pollen grains not stored in oil lost in vitro germinability within 15–30 days, while those stored in oils maintained some degree of germinability even after 60 days. Pollen samples stored in oils at –20° C did not show any decline in germinability or pollen tube vigour even after 6 months of storage. The results amply demonstrate the feasibility of using oils for short- and long-term pollen storage.     

Effect of dietary aflatoxin B1 on the growth response and haematologic changes of young Japanese quail

Feeding of aflatoxin B₁ at the rate of 0.5 ppm to young Japanese quail resulted in significant (p<0.01) decrease in body weight gain that became apparent on the third week. There was no significant difference in the mean values of haemoglobin, packed cell volume and total erythrocyte counts of quail chicks given aflatoxin B₁ in feed in comparison to those fed on a similar diet without aflatoxin. However, the total leucocyte count revealed an increase on the third week which was due to an increase in the percentage of heterophils and decrease in lymphocytes.     

Characterization and physiologic regulation of atrial natriuretic factor receptors in rabbit preglomerular renal microvessels.

There has been no direct demonstration of the presence of guanylate cyclase-linked atrial natriuretic factor receptors in renal preglomerular microvasculature. Using [125I]ANF, we have demonstrated the presence of high affinity (Kd = 80 pM) and low affinity (Kd = 7.2 nM) ANF receptors in membranes derived from rabbit renal preglomerular microvessels (afferent arterioles and interlobular arteries). These microvessels also exhibited the presence of particulate bound ANF-sensitive guanylate cyclase. The density of the high affinity ANF receptor in desoxycorticosterone-treated rabbits on a high-salt diet (31 +/- 3 fmol/mg protein) was nearly half of that seen in rabbits on a normal diet (53 +/- 4 fmol/mg protein; p less than 0.01, n = 4). Data from this study demonstrated the presence of renal preglomerular ANF receptors and suggested that these receptors (perhaps in addition to glomerular ANF receptors) may participate in the regulation of extracellular volume.     

Shift in product formation from acetate to ethanol using metabolic inhibitors inFusarium oxysporum

Summary Fusarium oxysporum 841 produces a mixture of ethanol and acetic acid from glucose, xylose or Avicel (microcrystalline cellulose) substrates. Some metabolic inhibitors viz. sodium azide, dinitrophenol and polyethylene glycol were used for shifting product formation from acetic acid to ethanol. Using these inhibitors 1.5- to 2- fold increase in ethanol production was achieved with significant repression (by 80 to 90%) of acetic acid. Almost theoretical yields of ethanol were obtained.     

Formation of acetic acid from cellulosic substrates byFusarium oxysporum

Summary Four strains of Fusarium oxysporum and a strain of Monilia brunnae were screened for their ability to convert cellulosic substrates into ethanol/acetic acid. These strains were found to utilize cellulose and produce extracellular cellulases. However, only F. oxysporum 841 was found to convert glucose, xylose, and cellulose into ethanol and acetic acid as major end-products under microaerobic conditions. Acetic acid at a level of 4.7 g/l resulted in a single-step process on potato pulp medium, indicating the potential of the strain for converting cellulosic substrates into acetic acid. Offprint requests to: K. Schügerl     

Studies on clinical signs and haematological alterations in pneumonic aspergillosis due to Aspergillus flavus in Japanese quail

Intratracheal inoculation of 2-week old quail chicks with Aspergillus flavus spores resulted in the development of clinical signs within 24 h of infection. These were characterized by dullness, depression, anorexia, accelerated breathing, gasping and prostration leading to death. These signs continued up to 7 days followed by considerable decrease in the intensity of the symptoms as well as number of birds showing clinical signs. Mortality occurred primarily in the first week with a majority of the birds dying from 2–4 days after infection. The overall mortality during a 6-week observation period was 25%. The average body weight of the infected chicks was slightly lower than that of controls; the difference being significant at 2, 3 and 42 days post-infection. There was no appreciable difference in the mean values of haemoglobin, packed cell volume and total erythrocyte count between the infected and control chicks at any stage of infection, but total leucocyte count revealed a significant increase (p<0.05) from 3–7 days post-infection. This was due to increase in the percentage of heterophils and decrease in lymphocytes.     

Solubilization of an Adenosine Uptake Site in Brain

Procedures are described for the solubilization of adenosine uptake sites in guinea pig and rat brain tissue. Using [3H]nitrobenzylthioinosine [( 3H]NBI) the solubilized site is characterized both kinetically and pharmacologically. The binding is dependent on protein concentration and is saturable, reversible, specific, and high affinity in nature. The KD and Bmax of guinea pig extracts are 0.13 +/- 0.02 nM and 133 +/- 18 fmol/mg protein, respectively, with linear Scatchard plots obtained routinely. Similar kinetic parameters are observed in rat brain. Adenosine uptake inhibitors are the most potent inhibitors of [3H]NBI binding with the following order of potency, dilazep greater than hexobendine greater than dipyridamole. Adenosine receptor ligands are much less potent inhibitors of binding, and caffeine is without effect. The solubilized adenosine uptake site is, therefore, shown to have virtually identical properties to the native membrane site. The binding of the adenosine A1 receptor agonist [3H]cyclohexyladenosine [( 3H]CHA) to the solubilized brain extract was also studied and compared with that of [3H]NBI. In contrast to the [3H]NBI binding site [3H]CHA binds to two apparent populations of adenosine receptor, a high-affinity site with a KD of 0.32 +/- 0.06 nM and a Bmax of 105 +/- 30 fmol/mg protein and a lower-affinity site with a KD of 5.50 +/- 0.52 nM and Bmax of 300 +/- 55 fmol/mg protein. The pharmacology of the [3H]CHA binding site is consistent with that of the adenosine receptor and quite distinct from that of the uptake [( 3H]NBI binding) site. Therefore, we show that the adenosine uptake site can be solubilized and that it retains both its binding and pharmacologic properties in the solubilized state.     

Mycoplasmalike Organisms (MLOs) Associated With the Witches' Broom Disease of Poplar

The witches' broom disease has been recently observed on poplars in Paris and its suburbs. The incidence of the disease appeared to be considerably high along main roads. The electron microscopic examination of 350 nm thick sieve tube sections revealed the presence of wall-less mycoplasmalike organisms (MLOs) in diseased samples of Populus alba var. nivea Wesm. They could not be found in their healthy counterparts.     

Structural studies on the specific capsular polysaccharide from Rhizobium trifolii, TA-1

The repeating unit of the specific capsular polysaccharide from the bacterium Rhizobium trifolii (TA)-1 has been shown to contain (a) terminal 4,6-O-(1-carboxyethylidene)-D-galactose (1 residue), (b) (1 → 3)-linked 4,6-O-(1-carboxyethylidene)-D-glucose (1 residue), (c) (1 → 4)-(1 → 6)-linked D-glucose (1 residue), (d) (1 → 4)-linked D-glucuronic acid (1 residue), and (e) (1 → 4)-linked D-glucose (4 residues). The pyruvylated sugars were shown to be positioned sequentially, and at least one other unit was interposed between them and the branch point.