Grapefruit and oroblanco enhance hepatic detoxification enzymes in rats: possible role in protection against chemical carcinogenesis

Citrus fruits are considered to be functional foods that promote good health. This study was carried out to assess the effect of oroblanco and grapefruit consumption on hepatic detoxification enzymes. Male Sprague-Dawley rats were provided with either regular drinking water (control) or experimental treatments of oroblanco juice, grapefruit juice, or a sugar mix for 6 weeks. After 1 week of treatment, half the animals in each group were injected with the procarcinogen 1,2-dimethylhydrazine. Grapefruit juice significantly increased activity and expression of the hepatic phase I enzyme, cytochrome P450 CYP1A1, with a marked trend toward enhanced NAD(P)H:quinone reductase (QR) activity. Oroblanco juice significantly increased glutathione S-transferase phase II enzyme activity along with CYP1A1 expression and a notable trend toward increased activity of both CYP1A1 and QR. These results suggest that these citrus fruits are bifunctional inducers, modulating both phase I and phase II drug-metabolizing enzymes to enhance hepatic detoxification.     

Bacterial infective arthritis of the coxofemoral joint in dogs with hip dysplasia

The objective of this study was to describe seven cases of unilateral bacterial infective coxarthritis from a total of 19 cases of bacterial infective arthritis (BIA), presenting over a two year period. We recorded the history, clinical signs, diagnostic process, treatment and clinical outcome in these cases. The data were obtained from medical records, review of the radiographs, and telephone follow-up with the owners. All of the dogs in this study had severe chronic osteoarthritis secondary to hip dysplasia, which caused periodic hind limb lameness. They were all admitted with severe acute hind-limb lameness. Pelvic radiographs were performed under general anaesthesia shortly after presentation, followed immediately by arthrocentesis of the affected joint. The synovial fluid was evaluated microscopically by direct smear and a sample was sent for culture and sensitivity. An attempt was not made to drain or lavage the affected joint during the course of treatment. The initial choice of antibiotics was empiric and subsequently modified, as required, based on the sensitivity results. Four of the dogs showed a rapid return to weight-bearing after the initiation of antibiotic treatment, and all of the patients returned to their pre-BIA level of function. Neither recurrent infections nor any adverse sequela requiring further intervention were reported by the owners on telephone follow-up.     

From killer to carer: steroid hormones and paternal behaviour

Mammalian parental investment (i.e. care of descendant offspring) is largely biased towards maternal contributions due to the specific feeding needs of mammalian offspring; however, varying degrees of paternal investment have been reported in about 10% of all mammalian species. Within the order Carnivora, paternal contribution to rearing offspring is particularly high: an estimated 32% of all studied carnivore species exhibit direct paternal care. Despite the prominence of paternal investment in carnivores, the endocrine basis of this behaviour is not well understood. This review examines the current – highly constrained – state of knowledge about the endocrine basis of carnivore paternal investment. We attempt to link changes in androgen and glucocorticoid levels with variation in direct and indirect paternal care behaviour making specific predictions regarding the way forward. Well-studied species, such as bat-eared foxes (Otocyon megalotis), dwarf mongoose (Helogale parvula) and meerkats (Suricata suricatta), where social dynamics are relatively well understood, can act as ideal model systems through which we may further investigate the endocrine basis of paternal investment in carnivores.     

Natural compounds derived from foods modulate nitric oxide production and oxidative status in epithelial lung cells

The effects of natural antioxidants on nitric oxide (NO) modulation and oxidative status were determined in rat epithelial lung cells (L-2). Cells were stimulated with cytokines and treated with one of the following: resveratrol, soybean saponin group B (SSB), quercetin, genistein, olive leaf polyphenol concentrate (OLPC), or N-acetyl-L-cystein (NAC). NAC had no effect on NO levels, whereas resveratrol and OLPC were found to be effective in reducing nitrite levels, modifying iNOS mRNA, and decreasing free radical production. OLPC affected the levels of MnSOD while resveratrol did not, indicating that they act via different pathways. Quercetin and genistein reduced nitrite levels without affecting iNOS levels, presumably by scavenging NO. SSB did not affect nitrite levels, but exposure did reduce iNOS mRNA expression and protein levels, possibly due to antioxidant activity. Naturally occurring antioxidants, in particular resveratrol and OLPC, may have therapeutic potential in the treatment of inflammatory diseases.     

Effect of phosphorus concentration in irrigation water on the development of jojoba cuttings

The effect of different phosphorus (P) levels in irrigation water on root and shoot development and elemental composition was studied in plantlets of two clones of jojoba, 64 and 879–154. High P in the irrigation water inhibited root development in both clones but to a greater degree for clone 879–154. Low P resulted in a decrease in magnesium (Mg) and calcium (Ca) content in the leaves, but had no effect on shoot growth or chlorophyll concentration.     

Survival,regrowth and rubber production of clipped guayule plants: Effects of irrigation regime,season and line

Guayule (Parthenium argentatum A. Gray) plants of USDA lines 11604,12229 and 11591 were subjected to irrigation regimes of 300,450, and 650 mm/per year and clipped at different ages over a period of several years. Survival, regrowth rates, biomass production, and rubber and resin accumulation in the plants after cutting at ground level were monitored. A survival rate of 92-100% was recorded in plants clipped in February (end of the dormant period) or October (just before the dormant period). In plants cut in summer (July) survival was less and presumably dependent on plant water status and age. No significant differences were evident among the different lines. The best plant development as determined by rate of height increase occurred in plants clipped in February. Total biomass production and total rubber yield (rubber or biomass at the time of cutting plus rubber or biomass at the second harvest) were lower in clipped than in unclipped plants. The reduction in rubber yield was most pronounced in plants of the medium and high water treatments.     

Long-term effect of irrigation with saline water on the development and productivity of jojoba clones

Summary

Three commercial clones of jojoba (Simmondsia chinensis) (64, Q-106 and 879–154) were planted in June 1991 at the Ramat Negev Experimental Station (Israel) and fertigated with water at three salinity levels, 1.2, 3.4 or 6.2 dS m^?1. The effects of salinity over three and a half years on key metabolic activities, on plant growth and development, on flowering characteristics, and on yield were studied. Salinity barely inhibited the rate of net photosynthesis, although it did reduce stomatal conductivity by about 50%. Salinity also affected the water status of the plants by reducing water potential. Growth of the plants was not greatly affected by salinity. It was found that jojoba plants accumulate sodium and chloride ions in their leaves and use a strategy typical of many halophytes to cope with the salinity. The effect of salinity on flower development was also studied, since the vitality of flowers is a key factor in obtaining seeds. Salinity did not affect the timing of the breaking of flower bud dormancy in the 1992-93 season, although it did delay flower bud growth in clones Q-106 and 64. Salinity brought forward the flowering of clone 879–154 by about a fortnight in the 1993-94 season, but did not affect the flowering pattern of the other clones. Fruit set was not inhibited by salinity in the 1994 or 1995 season, and no significant effects were found on yield and wax content in 1994 season, but yield was reduced by salinity in the 1995 season.     

The importance of pH in food selection by the tobacco whitefly,Bemisia tabaci

The tobacco whitefly,Bemisia tabaci Gennadius, was found to differentiate between pH values at the leyel of 0.25. It had a clear preference for media with pH values of 6.0 to 7.25 offeredin vitro, in both choice and no-choice situations, when “resting whiteflies” or survival was measured. The whiteflies showed a clear preference for a sucrose concentration of 15%. The addition of 10% sucrose to buffers at various pH values did not change the pattern of their pH preference. Inin vivo experiments whiteflies preferred old cotton leaves (120 days) to younger leaves (60 days). The pH of old leaves was 6.8 while that of young leaves was 5.9. These results may explain the fact that whiteflies attacked cotton plants in commercial fields only late in the season, when the pH values of the cotton leaves exceeded pH 6.