Long-term effects of dietary isoflavones on uterine gene expression profiles

Isoflavones (ISOs) are bioactive food ingredients of the traditional East Asian diet and currently discussed as alternatives to classical hormone replacement therapies and for reducing the prevalence of hormone-dependent cancers. Although there are many studies on ISOs, not much is known about their long-term effects.Therefore, we performed an animal experiment analyzing the effects of three different diets: a phytoestrogen-free diet, a diet supplemented with genistein (700 μg/g diet) and an ISO-high diet (232 μg daidzein and 240 μg genistein/g) at two distinct time points, juvenile (21 days) and adult (97 days). Exposure started prior to mating of the parents and throughout the life of the offspring.We observed a stronger increase of uterine wet weights in juvenile offspring with genistein exposure (1018 ± 350 mg/kg BW) than with ISO-high diet (497 ± 133 mg/kg BW). Whereas the expression of proliferation related genes (PCNA; Ki67; IGF-1; IGF-1R), analyzed by real-time-qPCR and Western blot, were significantly down-regulated in juvenile animals exposed to genistein. Additionally, genistein exposure led to estrogenic responses, observed upon increase of complement C3 and decrease of estrogen receptors gene expressions, while the exposure to ISO-high diet did not show these effects.In conclusion, both the time point on which phytoestrogen exposure starts together with the composition of the ingested phytoestrogen containing diet are of great importance for the biological response of the offspring.     

Territorial behaviour in southern impala rams (Aepyceros melampus Lichtenstein)

The role of territoriality was investigated by studying 25 impala rams at a reserve in the Waterberg region of South Africa (23°45′S, 28°23′E). Mean territorial tenure was 67.25 days (range 23–99), with a mean territory size of 21.0 ± 11.27 ha, compared with home ranges of 34.1 ± 9.03 ha for territorial rams and 58.8 ± 33.35 ha for bachelor rams, using the fixed kernel method. Territory boundaries remained constant, whilst the area surrounding important features such as water holes, appears to be neutral in terms of territoriality. The rut, as evidenced from peaks in chasing and roaring, lasted for 2 months from 10 April to 10 June 2001, with intensified behaviour including matings observed from 16 May to 4 June 2001. Territorial rams chase and roar more than bachelors. Flehmen and display behaviours are performed by all rams, whilst fights and other reproductive behaviours are generally rare. Bachelors browse more than territorial rams. Only bachelors spar and allogroom, and orally groom themselves more than territorial rams.     

New selective and differential medium for Vibrio cholerae and Vibrio vulnificus

Thiosulfate-citrate-bile salts-sucrose agar has been routinely used for the isolation of pathogenic vibrios, although its selectivity for Vibrio cholerae and Vibrio vulnificus is inadequate. Therefore, a new plating medium, cellobiose-polymyxin B-colistin agar, was developed for the isolation of these two species. Cellobiose-polymyxin B-colistin agar demonstrated a significant advantage over other media designed for the isolation or differentiation of vibrios: of both the 136 strains representing 19 Vibrio species and the marine isolates of the genera Pseudomonas, Flavobacterium, and Photobacterium, only V. vulnificus and V. cholerae were able to grow. Furthermore, the fermentation of cellobiose by V. vulnificus allowed for the easy differentiation of these two species. This medium offers significant potential as a selective and differential medium for these two pathogenic vibrios.     

Xanthophylls and abscisic Acid biosynthesis in water-stressed bean leaves

Experiments were designed to obtain evidence about the possible role of xanthophylls as abscisic acid (ABA) precursors in water-stressed leaves of Phaseolus vularis L. Leaves were exposed to ¹⁴CO₂ and the specific activities of several major leaf xanthophylls and stress-induced ABA were determined after a chase in ¹²CO₂ for varying periods of time. The ABA specific radioactivities were about 30 to 70% of that of lutein and violaxanthin regardless of the chase period. The specific activity of neoxanthin, however, was only about 15% of that of ABA. The effects of fluridone on xanthophyll and ABA levels and the extent of labeling of both from ¹⁴CO₂ were determined. Fluridone did not inhibit the accumulation of ABA when leaves were stressed once, although subsequent stresses in the presence of fluridone did lead to a reduced ABA accumulation. The incorporation of ¹⁴C from ¹⁴CO₂ into ABA and the xanthophylls was inhibited by fluridone and to about the same extent. The incorporation of ¹⁸O into ABA from violaxanthin which had been labeled in situ by means of the violaxanthin cycle was measured. The results indicated that a portion of the ABA accumulated during stress was formed from violaxanthin which had been labeled with ¹⁸O. The results of these experiments are consistent with a preformed xanthophyll(s) as the major ABA precursor in water-stressed bean leaves.     

Conversion of xanthoxin to abscisic Acid by cell-free preparations from bean leaves

Cell-free extracts from the leaves of Phaseolus vulgaris L. convert xanthoxin to abscisic acid. The enzyme activity in dialyzed or acetone-precipitated extracts shows a strong dependence on either NAD or NADP. The enzyme activity appears to be cytosolic with no significant activity observed in chloroplasts. The activity was observed in extracts from roots of Phaseolus vulgaris, and also in extracts prepared from the leaves of Pisum sativum L., Zea mays L., Cucurbita maxima Duchesne, and Vigna radiata L. Neither water stress nor cycloheximide appear to significantly affect the level of enzyme activity in leaves. No intermediates between xanthoxin and abscisic acid were detected.     

Amino acid-dependent transport of sugars by Fusobacterium nucleatum ATCC 10953.

Resting cells of Fusobacterium nucleatum 10953 (grown previously in a medium containing glucose) failed to accumulate glucose under aerobic or anaerobic conditions. However, the addition of glutamic acid, lysine, or histidine to anaerobic suspensions of cells caused the immediate and rapid accumulation of glucose. Except for the amino acid-dependent transport of galactose and fructose (the latter being transported at approximately one-third the rate of glucose), no other sugars tested were accumulated by the resting cells. Amino acid-dependent uptake of sugar(s) by F. nucleatum was abolished by exposure of cells to air, and under aerobic conditions the rates of fermentation of glutamic acid and lysine were less than 15% of the rates determined anaerobically. The energy necessary for active transport of the sugars (acetyl phosphate and ATP) is derived from the anaerobic fermentation of glutamic acid, lysine, or histidine. Competition studies revealed that glucose and galactose were mutual and exclusive inhibitors of transport, and it is suggested that the two sugars (Km = 14 microM) are translocated via a common carrier. The products of amino acid-dependent sugar transport were recovered from resting cells as ethanol-precipitable, high-molecular-weight polymers. Polymer formation by F. nucleatum, during growth in medium containing glucose or galactose, was confirmed by electron microscopy.     

Age-related changes in oxidized proteins

We have previously described the oxidative inactivation of several key metabolic enzymes by a variety of mixed function oxidation systems. Because many of the enzymes which are inactivated have been shown by others to accumulate as inactive or less active forms during cellular aging, we have examined the levels of oxidatively modified proteins in two model systems used for studies on aging. The results show that levels of oxidatively modified proteins increase with age in circulating erythrocytes, and this change is correlated with the loss of marker enzyme activity. Our studies also show that in cultured fibroblasts from normal donors the levels of oxidatively modified proteins increase only after the age of 60. However, the levels of oxidatively modified proteins in fibroblasts from individuals with progeria or Werner's syndrome are significantly higher than age-matched controls. Moreover, treatment of glucose-6-phosphate dehydrogenase with a mixed function oxidation system leads to oxidative modification and increased heat lability of the enzyme. Taken together these results suggest that loss of functional enzyme activity and increased heat lability of enzymes during aging may be due in part to oxidative modification by mixed function oxidation systems.