Antibody formation: initiation in "nonresponder" mice by macrophage synthetic polypeptide RNA

The RNA extracted from normal peritoneal macrophages exposed to a linear, random synthetic polypeptide, Glu(60)Ala(30)Tyr(10), initiated an immune response in C57B1/6J mice, although this strain responds very poorly to the antigen itself. From 10 to 150 micrograms of RNA obtained from mouse, rat, or rabbit macrophages was injected intraperitoneally into recipient mice, and specific antibody was detectable by passive hemagglutination 3 to 4 weeks later. Treatment of the RNA with ribonuclease destroyed its ability to initiate a specific immune response. The RNA contained by weight 0.02 percent of the (specific) antigen. The RNA obtained from cells incubated with a second polypeptide, Glu(36)Lys(24)Ala(40), initiated a response specific for this polymer. This RNA even when incubated in vitro with Glu(60)Ala(30)Tyr(10) failed to initiate antibody formation specific for Glu(60)Ala(30)Tyr(10).     

Solvent effects on the molecular properties of pectins

Measurements revealed that LiAc/HAc buffer, when compared with other solvents, gave relatively low values of turbidity for five commercial pectins with various apparent molar masses and degrees of methyl esterification (DE). Therefore, HPSEC with on-line light scattering and viscosity detection was employed to compare LiAc/HAc buffer against NaNO(3) solution, a commonly used mobile phase for measuring the molecular properties of these pectins and an additional pectin prepared by microwave extraction. Microwave-extracted pectin was included in the study for its higher molar mass and DE compared with commercial pectins. Most commercial samples were more soluble and had a higher molar mass when dissolved in NaNO(3) than in LiAc/HAc buffer, whereas the microwave-extracted pectin was more soluble in LiAc/HAc buffer and had about the same molar mass. Furthermore, association fragments of pectin contained in samples were more dissociated by LiAc/HAc buffer than by NaNO(3). For the samples studied, weight-average molar masses ranged from about 41000 to 307000, weight-average intrinsic viscosities from about 0.86 to 9.76 dL/g, z-average radii of gyration from about 13 to 45 nm, and Mark-Houwink constants from about 0.62 to 0.94.     

THE CHANGES IN RAT KIDNEY COCARBOXYLASE ASSOCIATED WITH THE INJURIOUS EFFECTS OF dl-SERINE

When rats on either a stock or a vitamin B deficient diet are given the amino acid dl-serine by stomach tube, there is a fall in the cocarboxylase concentration of the kidney. This organ exhibits marked damage. There is, also, a lessened tendency for cocarboxylase to disappear from the tissue homogenate upon anaerobic incubation in vitro. In animals on the stock diet, only, there is a recovery of the normal cocarboxylase level. The probable relation of these findings to the mechanism of the production of the injurious action of serine is discussed. We would like to acknowledge the helpful criticisms of Dr. C. Artom.     

Spatial analysis of seroconversion of sentinel cattle to bluetongue viruses in Queensland

Objective To assess quantitatively the spatial distribution of seroconversion of Queensland cattle to bluetongue viruses.
Design A sentinel herd study. Sample population Sixty-nine sentinel herds at 30 locations.
Procedure Spatial clustering of seroconversion to blue-tongue viruses was investigated during the period from 1990 to 1994.
Results Seroconversion to only two bluetongue virus serotypes, 1 and 21, was observed. The 14 herds, in which seroconversion to bluetongue virus serotype 1 was detected, were located only along the eastern coastal and subcoastal region of Queensland, and were significantly (P < 0.05) clustered. Locations at which seroconversion to serotype 21 was detected, were not significantly clustered. The results generally agree with field observations, except for the failure to detect seroconversion to bluetongue viruses in north-western Queensland.
Conclusion Bluetongue infection of cattle in north-western Queensland may be temporally sporadic. The dominance of serotype 1 in the Queensland cattle population may be the result of differential transmission by potential vector species. Long-term surveillance programs are important for defining disease status of animal populations.     

Alpaca plant poisonings: nitrate–nitrite and possible cyanide

Nitrate–nitrite poisoning killed four adult alpacas and induced the abortion of a full-term fetus after access to oaten hay ( Avena sativa ) containing 3.2% KNO₃ equivalent in dry matter. Necropsy findings were cyanosis, dark-coloured blood, and pulmonary congestion and oedema. Aqueous humour from two adults contained 25 mg NO₃/L and that from the fetus contained 10 mg NO₃/L. Cyanide poisoning possibly killed two adult wether alpacas that ate a garden-cultivated variety of Osteospermum ecklonis (South African daisy, bietou) with a cyanide potential of 6800 mg HCN/kg dry matter.     

Effect of Oxytocin Treatment on Artificial Insemination with Frozen–Thawed Semen in Murciano–Granadina Goats

The site where the semen is deposited appears to be one of the most important factors affecting pregnancy of inseminated goats. In Murciano–Granadina (MG) goats, post-cervical insemination is achieved in a limited number of females. An effective way to increase fertility rate could be by increasing post-cervical inseminations. Effect of exogenous oxytocin application to facilitate the cervical penetration and its effect on kidding rate and prolificacy in MG goats were investigated. Oestrus was synchronized using progesterone-impregnated sponges for 11 days. Females were randomly divided into three groups (n = 190) and received either an i.v. injection of 100 or 200 IU of oxytocin or saline solution 15 min before being inseminated. Data on semen deposition depth were recorded for each animal using a catheter scaled in centimetres (up to 4 cm). Depth of semen deposition was affected by the oxytocin treatment (p < 0.05). Oxytocin enhanced cervical passage only with the dose of 200 IU compared with the control group, increasing the deposition depth (2.9 cm vs 1.9 cm). No significant effect of oxytocin treatment on kidding rate and prolificacy was detected. Depth of semen deposition affected kidding rate (p < 0.01). In conclusion, oxytocin treatment improved the depth of semen deposition in AI of MG goats, but kidding rate and prolificacy was not affected. More studies must be conducted to assess the minimal effective dose required for sufficient cervical dilation, and to determine the effects of such doses of oxytocin on uterine motility, sperm transport and fertility in goats.     

A phenomenological model of dry matter partitioning among plant organs for simulation of potato growth

A mathematical model of the process of dry matter partitioning among plant organs during the autotrophic period of potato development is presented. The model consists of a system of differential equations based on the concept of a sink. The sink strength is proportional to the dry matter (DM) biomass, subject to total photosynthesis production. The ageing process is taken into account. The equations contain a set of parameters which are estimated by fitting the numerical solution to the empirical data recorded from growth analysis in field experiments.