Influence of Clavicipitaceous Endophyte Infection in Ryegrass on Development of the ParasitoidMicroctonus hyperodaeLoan (Hymenoptera: Braconidae) inListronotus bonariensis(Kuschel) (Coleoptera: Curculionidae)

Laboratory experiments were conducted to examine the effect of ryegrass infection by the endophytic fungusAcremonium loliiLatch, Christensen and Samuels onMicroctonus hyperodaeLoan, a parasitoid ofListronotus bonariensis(Kuschel). Progression of parasitoids through the larval instar stages was shown to depend on adequate nutrition of the weevil host. Compared to confinement on endophyte-free ryegrass, parasitized weevils held on nonpreferred diets comprising leaf segments from endophyte-infected ryegrass and switchgrass contained parasitoid larvae with retarded development. Similarly, development of parasitoid larvae was retarded in hosts feeding on artificial diet containing diterpenes and alkaloids ofA. loliiorigin. Several diterpenes incorporated into the diet reduced survival of the parasitoid larvae. Attack rate of parasitoids was reduced when the quality of potential host weevils was compromised by confinement on nonpreferredA. lolii-infected ryegrass or without food for 14 days.     

Immunohistochemical localization of adenosine 3':5'-cyclic monophosphate in female ixodid tick Amblyomma americanum (L.) salivary glands

Localization of adenosine 3':5'-cyclic monophosphate (cyclic AMP) in alveoli of salivary glands of female Amblyomma americanum (L.) was accomplished with an indirect immunofluorescent technique. Little cyclic AMP fluorescence was seen in Type I alveoli in glands of unfed females but considerable fluorescence was seen in Type I alveoli of glands obtained from females that had fed. The most intense cyclic AMP fluorescence was observed in complex granular cells of Type II and III alveoli in glands of unfed females and glands from females in early stages of tick feeding. In the latter stages of tick feeding an increase in fluorescence in Type III alveoli was observed in cells near the lumen, possibly adluminal interstitial or transformed granular cells.     

System for DNA sequencing with resolution of up to 600 base pairs

A system capable of resolving about 500 bases is of interest for sequencing of longer DNA molecules. Studies on further optimization of resolution on DNA sequencing gels were carried out. The effect of physico-chemical properties of gels and buffers on resolution were tested, e.g. ionic strength and pH of buffers, different buffer systems, acrylamide concentration, crosslinker concentration, type of crosslinker, temperature of polymerization, denaturing conditions, gel length and thickness. Tested were as well different running conditions like electric field, gel temperature, dimension of sample slots. Gels 0.1-0.2 mm thick and up to 1.2 m long were cast and tested routinely. Gel lengths of 60-70 cm (for sequencing up to 350-400 bases) to about 100 cm (above 400 bases) are practicable. Little is gained in resolution by increasing the gel length from 1 to 1.2 m. Resolution was improved using 0.1 mm thick gels, at a higher pH value of 8.6-8.8, and molarity increased to 0.2 M. The sequencing pattern in the region of higher bases could be better resolved on a twice-magnified picture of that region on the autoradiogram. With the long gels (70-120 cm), it is advantageous to obtain the sequence overlap by running in parallel gels of different concentrations, without re-application of samples, all loaded at the same time. Buffer chamber for running of two of three gels and thermostating plates up to 1.2 m long were designed. In this way four to six thermostated gels can be run from a power supply with two inputs. Three 1 m long gels (concentrations: 4%, 6%, 12-16%) are loaded with several samples of DNA to be sequenced and run in parallel without re-application of the samples. With good samples, the sequence overlap from the gels could be counted up to 500 base pairs, with exceptionally good samples closer to 600 bases. At present this number seems to be near the limit of the resolving power of the polyacrylamide gels.     

The amino acid sequence of the tyrosyl-tRNA synthetase from Bacillus stearothermophilus

The primary structure of the tyrosyl-tRNA synthetase (TyrTS) of Bacillus stearothermophilus has been deduced from the nucleotide sequence of the cloned gene and from the amino acid sequence of peptides isolated from the purified enzyme. TyrTS (B. stearothermophilus) has a molecular weight of 47316 and the sequence is 56% homologous with that of TyrTS (Escherichia coli). The binding domain for the substrate intermediate tyrosyl adenylate is located in the N-terminal portion of the polypeptide and is highly conserved in both enzymes. Several lysine residues, which are shielded from acetylation in the TyrTS-tRNATyr complex, are also located in a stretch of highly conserved sequence.     

Activation by dopamine of patterned motor output from the buccal ganglia of Helisoma trivolvis

The buccal ganglia of the snail, Helisoma trivolvis, contain an intrinsic system of dopamine-containing neurons (Trimble, Barker, and Bullard, 1983). Dopamine, when bath applied to the isolated buccal ganglia, activates patterned motor output in a dose-dependent fashion. Haloperidol blocks the activating effect of dopamine, but the similar activation evoked by serotonin is not blocked by haloperidol. We suggest that there are two separate mechanisms for activating patterned motor output from the buccal ganglia. One is serotonergic, emanating from identified cerebral ganglion cells (Granzow and Kater, 1977), while the other is dopaminergic, involving neurons intrinsic to the buccal ganglia.     

4-Methylumbelliferyl esters as fluorogenic substrates for proteases

4-Methylumbelliferyl esters of amino acid derivatives have been synthesized using the carbodiimide, disulphite and carbonate methods. Of these, the first was shown capable of preparing 2-naphthyl and 4-methylumbelliferyl esters of benzoylglycine, benzyloxycarbonyl glycine and benzyloxycarbonyl-citrulline but not of benzoyl-N^G-nitroarginine. 2-Naphthyl benzoyl-N^G-nitroargininate was prepared successfully using di(2-naphthyl)sulphite. Bis(4-methylumbelliferyl)sulphite could not be prepared but 4-methylumbelliferyl benzoyl-N^G-nitroargininate was obtained by the use of an equilibrium method using diphenyl sulphite in the presence of 4-methylumbelliferone. A new reagent, phenyl 4-methylumbelliferyl carbonate, was synthesized and used for the preparation of the 4-methylumbelliferyl esters of benzoylglycine, benzyloxycarbonylglycine and benzoyl-N^G-nitroarginine. The 4-methylumbelliferyl esters of benzyloxycarbonylglycine and benzyloxycarbonylcitrulline were shown to be good substrates for the assay of proteases, including chymotrypsin (EC 3.4.21.1) and trypsin (EC 3.4.21.4). Disadvantages of 4-methylumbelliferyl esters are discussed.     

The genes coding for the cardiac muscle actin, the skeletal muscle actin and the cytoplasmic beta-actin are located on three different mouse chromosomes.

The actins are a group of highly conserved proteins encoded by a multigene family. We have previously reported that the skeletal muscle actin gene is located on mouse chromosome 3, together with several other unidentified actin DNA sequences. We show here that the gene coding for the cardiac muscle actin, which is closely related to the skeletal muscle actin (1.1% amino acid replacements), is located on mouse chromosome 17. The gene coding for the cytoplasmic beta-actin is located on mouse chromosome 5. Thus, these three actin genes are located on three different chromosomes.     

The production of the enzyme dextransucrase using nonaerated fermentation techniques

High yields of the enzyme dextransucrase have been produced repeatedly by fed-batch fermentation techniques. Activities in excess of 21.9 U/cm(3) have been obtained by culturing Leuconostoc mesenteroides NRRL B-512(F) under nonaerated fed-batch fermentation conditions. Aerobic fermentations carried out under identical conditions have consistently produced enzyme of less than 17 U/cm(3), but with no difference in the final cell concentration in the broth. Different types of yeast extract have been found to have significant effect on the final cell concentration and more especially on the enzyme activity with enzyme yields varying by as much as 50% when different types of yeast extracts were used.     

Longevity and fecundity ofAcarus siro on four field and eight storage fungi

Egg production and longevity of isolated pairs ofAcarus siro L., when fed on mycelial pellets of selected fungi from shake cultures, were compared with those on a control diet of wheatgerm and brewer's yeast. The mites were always less productive on the fungal diet. They did best on the yeastHansenula anomola and worst on the field fungusAlternaria alternata. There was very little difference between egg production on wheatgerm alone and that on the control diet of wheatgerm and yeast. On the control diet, males lived longer than females. Fungal diets usually shortened male lives, while in two-thirds of the cases female lifespans were unaffected.