Biochemical properties of pigeon milk and its effect on growth

Summary The avian juvenile food pigeon milk was studied for its chemical composition and effect on growth in vivo and in vitro. Pigeon milk on a wet weight basis consisted of 9–13% protein, 9–11% fat, 0.9–1.5% carbohydrate, 0.8–1.1% ash, 0.10–0.12% non-protein nitrogen, energy content 5.6–6.8 kcal·g^-1. Except for proteins there was little or no decrease in pigeon milk constitutents during the first week of secretion. Pigeon milk proteins consisted of trichloroacetic acid (precipitable), trichloroacetic acid (soluble), and free amino acid components in the ranges 8.4–12.1%, 0.5–0.7% and 1.4–2.5%, respectively; whereas the level of trichloroacetic acid (precipitable) and trichloroacetic acid (soluble) components decreased by about 30%, that of the free amino acids increased by 9% in the first week. About 0.6–1.0% of pigeon milk sugar was found in the trichloroacetic acid (soluble) fraction and increased by 67% in the first week. The remainder was found in the trichloroacetic acid (precipitable) fraction and did not change during this period. Major lipids of pigeon milk were the neutral lipids (7.8–8.4%); the minor lipids were glycolipids (0.9–1.6%), phospholipids (0.5–1.4%) and cholesterol (0.5–0.6%). Squabs fed pigeon milk increased their body weight by 22-fold in the first 3 weeks after hatching, and crude extracts of pigeon milk stimulated the growth of cultured hamster ovary cells. These results reflect the ability of pigeon milk to stimulate growth both in vivo and in vitro.Abbreviations AOAC association of official analytical chemists - BRIT board of radiation and isotope technology - CHO chinese hamster ovary - DNA deoxyribonucleic acid - EDTA ethylenediaminetetra-acetic acid - FCS foetal calf serum - GF growth factor - GS goat serum - MEM minimum essential medium - NPN nonprotein nitrogen - PBS phosphate-buffered saline - PM pigeon milk - TCA(P) trichloroacetic acid precipitable fraction - TCA(S) trichloroacetic acid soluble fraction     

Comparative studies on the wide frequency band electrocardiogram and vectorcardiogram in pigeon and mouse

Wide frequency band ECG and vectorcardiogram in anesthetized pigeon and mouse were studied from the standpoint of comparison. The key results were as follows: in pigeon, the direction of the main QRS was inverted in leads II, III and aVF, and upright in lead aVR, which was contrary to that in mouse. The T wave was upright in leads II, III and aVF, but inverted in lead aVR in pigeon, which was the same as that in mouse. In pigeon, there was a large notch on the upstroke of the S wave in lead II without exception, but there was no such notch in the corresponding lead in mouse. The QRS vector loop in the frontal plane lay between -90 and -180 degrees in pigeon, while that of mouse lay between 0 and 90 degrees. The relative power of high frequency range (80-1000 Hz) of the QRS in lead II was approximately 15% in pigeon, but 55% in mouse. The direction of the main QRS was contrary in pigeon and mouse because the subepicardial muscles were depolarized before the subendocardial muscles in pigeon, but the latter were depolarized before the former in mouse. The direction of the T waves was the same in both pigeon and mouse because subepicardial muscles were all repolarized before subendocardial muscles.     

Comparative studies on the growth dynamics of two genetically distinct isolates of Giardia duodenalis in vitro.

The in vitro growth behaviour of the intestinal protozoan Giardia duodenalis was studied in detail and comparisons were made between two genetically and biologically distinct cloned isolates. Replicates of each clone were grown at six different initial cell concentrations and in culture media at four different pH values. Significant differences in in vitro growth were found between the two isolates, BAH12 and P1. BAH12 had a specific narrow pH requirement, with satisfactory growth only obtained at pH 6. The mean generation time of BAH12 at pH 6 between days 1 and 3 was 10.8 h, compared to an average of 6 h for the same period for P1, both at pH 6 and pH 7. Comparative health of cultures was assessed during both the pH and growth experiments using a suite of six variables. Consistent changes in the health of cultures over time were found to reflect growth behaviour over time. These results provide the first detailed evidence that genetically different isolates of Giardia may differ in such fundamental biological parameters as growth rate and pH requirements. These differences may have important epidemiological and taxonomic implications.     

Bismuth-inhibitory effects on bacteria and stimulation of fungal growth in vitro

Bismuth salicylate was found to inhibit the growth of a range of bacteria and yeast, “Candida albicans”. In general the growth of bacteria did not result in increase in bismuth solubilisation, in contrast, bismuth solubilisation increased following the growth of C. albicans. A significant increase in the biomass (dry weight) of Aspergillus niger and Aspergillus oryzae occurred in vitro when these fungi were grown in the presence of bismuth salicylate. Biomass increase occurred over a range of bismuth compound additions, which in the case of A. oryzae was associated with increase in the solubilisation of the insoluble bismuth compounds.     

Comparative studies of cytokinins on in vitro propagation of Bacopa monniera

A mass in vitro propagation system for Bacopa monniera (L.) Wettst. (Scrophulariaceae), a medicinally important plant, has been developed. A range of cytokinins have been investigated for multiple shoot induction with node, internode and leaf explants. Of the four cytokinins (6-benzyladenine, thidiazuron, kinetin and 2-isopentenyladenine) tested thidiazuron (6.8 μM) and 6-benzyladenine (8.9 μM) proved superior to other treatments. Optimum adventitious shoot buds induction occurred at 6.8 μM thidiazuron where an average of 93 shoot buds were produced in leaf explants after 7 weeks of incubation. However, subculture of leaf explants on medium containing 2.2 μM benzyladenine yielded a higher number (129.1) of adventitious shoot buds by the end of third subculture. The percentage shoot multiplication (100%) as well as the number of shoots per explant remained the high during the first 3 subculture cycles, facilitating their simultaneous harvest for rooting. In vitro derived shoots were elongated on growth regulator-free MS medium and exhibited better rooting response on medium containing 4.9 μM IBA. After a hardening phase of 3 weeks, there was an almost 100% transplantation success in the field. This revised version was published online in June 2006 with corrections to the Cover Date.     

Comparative in vitro cytogenetic studies in mercury-exposed human lymphocytes

As part of a long-term cytogenetic research project on mercury, we studied the in vitro clastogenic capacity of HgCl2 and CH3HgCl as well as their influence on chromosome segregation by means of a computer-aided chromosome distribution study in metaphase plates. As in other in vitro studies published elsewhere, we exposed human peripheral blood lymphocytes to different concentrations of the mercury compound during a limited period of the pre-DNA synthetic stage (G1-S) or from that stage up to mitosis (G1-M). For both exposure periods and both mercury compounds we observed a rather important clastogenic effect as well as a dissociation of the (normally highly associated) acrocentrics. The results do indicate, in conjunction with previously published data, that mercury compounds alter the chromosome segregation at lower concentrations than those observed for clastogenicity. Moreover, the effects on chromosome segregation are not necessarily due to binding to spindle proteins. Binding to--and inactivation of RNA polymerase I may for example be another mechanism of action which is more important for the inorganic form of mercury than for the organic form.     

Comparative studies on lipid and colony-stimulating factor-induced macrophage growth

We previously reported that lipids such as cholesterol esters, triglycerides, and some phospholipids that constitute cell membranes or serum lipoproteins induced growth of mouse peritoneal macrophages in vitro. In this paper, we compared the macrophage growth-stimulating activity of cardiolipin (CL), an active phospholipid with that of CSF-1. Growth kinetics and maximal degree of growth of exudated macrophages induced by CL were similar to those of CSF-1. CL did not stimulate macrophages to release soluble macrophage growth factors. Also, the activity of CL was not blocked as much by anti-CSF-1, suggesting that most of the effect of CL was direct and not mediated by CSF-1 or other protein factors. There was no synergistic effect between CL and CSF-1. CL induced growth of both exudate and resident macrophages, whereas CSF-1 induced very little resident macrophage growth. Furthermore, although the growth-stimulating activities of both substances were inhibited by IFN-gamma and TNF, CL was more resistant to these inhibitory effects. These results suggest that the lipid has some different characters from CSF-1 and may induce the growth of resident macrophages in inflammations or tumors.