Growth inhibition of herpes simplex virus-type 1 in calphostin C-treated astrocytes

The aim was to evaluate the effects of calphostin C (CC), a protein kinase C inhibitor, on lytic herpes simplex virus-type 1 infection of cultured rat astrocytes. At 24 h postinjection, the cell culture receiving CC treatment at 50 nM concentration showed decreased cell detachment and retraction versus untreated infected controls; likewise, the infective virus yield was significantly lower in a dose-dependent manner. In contrast, image analysis failed to disclose differences in viral antigen immunolabeling at low drug concentrations thus suggesting that CC-induced inhibition of cytopathic effects and infectivity taken place through mechanisms not involving viral protein synthesis. Given the low dose required and the apparent lack of cytotoxic effects, present findings encourage additional studies on CC antiviral potential in the whole organism.     

Shortening of the poly(A) region of mouse globin messenger RNA

Nucleated erythroid cells isolated from the spleens of anemic mice were used to investigate the processing of the polyadenylic acid region of globin mRNA. Cells were labeled in media containing [3H] adenosine and transferred to media containing no radioactive precursor and incubated further in the presence or absence of actinomycin D. After various times following the transfer of the cells, globin mRNA was isolated using a combination of oligo(dT)-cellulose affinity chromatography, sucrose density centrifugation, and globin cDNA (the complementary DNA copy of globin mRNA)-cellulose affinity chromatography. The size of the poly(A) region was determined by polyacrylamide gel electrophoresis of the T1 and pancreatic RNase-resistant fragments. The prelabeled poly(A) region which initially comprises approximately 150 adenylate residues was found to become shorter with time, both in cells incubated in medium containing no radioactive precursor and in the presence of actinomycin D. After 9 h of incubation in the presence of actinomycin D, two major size classes of poly(A) were observed, one containing 35 to 45 adenylic acid residues and the other containing 55 to 65 residues. These two size classes are similar to those found in circulating reticulocytes suggesting that the poly(A) shortening observed in these cell incubation studies is similar to that which occurs in vivo. Two protein synthesis inhibitors, emetine and cycloheximide, were investigated with respect to their effect on poly(A) shortening. Neither drug inhibited the shortening of the poly(A) region of globin mRNA, suggesting that protein synthesis is not required for this process to occur.     

Identification of male-specific volatiles from nearctic and neotropical stink bugs (Heteroptera: Pentatomidae)

Males of the Central American stink bug species,Euschistus obscurus, produce an attractant pheromone composed of a blend of compounds characteristic of North AmericanEuschistus spp. and the South American soybean pest,E. heros. The range ofE. obscurus extends into the southern United States, the species is easy to rear, and males produce an exceptionally large quantity of pheromone (>0.5µg/day/male). These factors madeE. obscurus useful for characterizing the novel pheromone components ofE. heros without importing this pest species into the United States.Euschistus obscurus males produce methyl (2E,4Z)-decadienoate (61 %) in abundance, which is characteristic of North American species, and methyl 2,6,10-trimethyltridecanoate (27%), the main male-specific ester ofE. heros. The chirality ofEuschistus spp. methyl-branched esters, and field activity of synthetic formulations, remain to be determined.     

Ribosomal protein L7/L12 is required for optimal translation

We have tested the performance in vitro of Escherichia coli ribosomes containing or lacking the protein L7/L12. When the experiments are performed in an optimized mixture of ions (polymix), L7/L12 is required for maximal rate of synthesis as well as for minimal missense error frequency. The results in conventional Tris/Mg2+/NH4Cl buffers are different; in these buffers, only the rate of synthesis is strongly dependent on the presence of L7/L12. In addition, we show that there is a large difference between the optimal Mg2+ concentration required for speed of translation and that for accuracy of translation in conventional buffer. These optima are very close in polymix. Finally, we show that the contribution of L7/L12 to the speed of translation is obscured in translation systems that are limited by substrates. We conclude that it is not possible to analyze details of the mechanism of translation in conventional buffers.     

Optimizing nutrient ratios in milk replacers for calves less than five weeks of age

In trials 1A and 1B, the objective was to determine whether crude protein (CP) concentration could be lowered from 27% CP if Lys and Met were held constant. Forty-five calves per trial were fed milk replacer (MR) powders that contained 23, 25, or 27% CP (dry matter basis) from whey protein. Each MR powder contained 17% fat, 2.44% Lys, 0.75% Met, and 1.56% Thr by adding l-Lys, dl-Met, and l-Thr, and were fed at 0.681 kg/d. In trial 2, the objective was to estimate an optimal CP-to-energy ratio for 2 different amounts of MR fed. Ninety-six calves were fed 1 of 8 MR powders (dry matter basis): 1) 23% CP fed at 0.545 kg/d, 2) 25% CP fed at 0.545 kg/d, 3) 27% CP fed at 0.545 kg/d, 4) 29% CP fed at 0.545 kg/d, 5) 23% CP fed at 0.654 kg/d, 6) 25% CP fed at 0.654 kg/d, 7) 27% CP fed at 0.654 kg/d, and 8) 29% CP fed at 0.654 kg/d. In each MR, l-Lys and dl-Met were added to achieve a Lys:CP ratio of 0.09 and a Met:Lys ratio of 0.31. Holstein calves initially 2 to 3 d old and 43 ± 1 kg of body weight (BW) from 1 farm were fed MR until weaning at 28 d and were monitored for a total of 56 d. Calves were fed an 18% CP starter and water free choice from d 1 and were housed in individual pens bedded with straw in a naturally ventilated nursery with no added heat. Trials 1A and 1B were analyzed individually as completely randomized designs with repeated measures in a mixed model. Trial 2 was analyzed as a completely randomized block design with a factorial arrangement of 2 rates and 4 CP concentrations with repeated measures in a mixed model. In trials 1A and 1B, preweaning average daily gain (ADG) and feed efficiency declined as CP declined. Postweaning performance did not differ among treatments. In trial 2, preweaning ADG was greater and starter intake was lower at the high MR compared with the low MR feeding rate. Pre- and postweaning and overall ADG increased quadratically as CP increased. Preweaning MR rate interacted with CP; thus, at the low MR rate, providing 3.26 Mcal of metabolizable energy (ME)/d (0.0656 Mcal/kg of BW daily), 51.5 g of CP/Mcal of ME was the optimal ratio in the MR (25% CP, 17% fat, 2.26% Lys, and 0.68% Met) to maximize ADG. At the high ME intake, providing 3.71 Mcal/d (0.0743 Mcal/kg of BW daily), 55.0 g of CP/Mcal of ME was the optimal ratio in the MR (27% CP, 17% fat, 2.44% Lys, 0.75% Met) to maximize ADG.