Effect of oxytocin infusion on luteal blood flow and progesterone secretion in dairy cattle

The objective of this study was to investigate the effects of oxytocin infusion on corpus luteum (CL) function during early to mid-diestrus by measuring luteal size (LS) and luteal blood flow (LBF) along with plasma levels of progesterone (P4) and prostaglandin metabolites (13,14-dihydro-15-keto-prostaglandin F_2α, PGFM). On day (D) 7 of the estrus cycle (D1 = ovulation), seven cows received 100 IU of oxytocin (OXY) or placebo (PL) following a Latin square design. LS and LBF increased in both groups over time and no differences were observed between the groups. PGFM did not differ either within the groups over time or between the groups at any time point. P4 of the OXY group was higher compared to that of the the PL group 360 min after the infusion (p = 0.01) and tended to be higher at the time points 450 min, 48 h, and 72 h (all p = 0.08). Results from this study support the hypothesis that OXY is not directly involved in the mechanism(s) governing blood flow of the CL and has no remarkable effects either on luteal size or P4 and PGFM plasma levels. Further investigation is needed to elucidate the role of OXY in CL blood flow during early and late luteal phases.     

Clinical, histopathological and therapeutic considerations in a flock of sheep with facial staphylococcal-associated dermatitis

In a flock of 290 sheep, a total of 20 ewes (6.9%) with an age range of 1.5-4 years, developed a nonpruritic dermatitis characterized by alopecia/hypotrichosis, erythema, hyperpigmentation, crusting, superficial ulcers, exudation and thickening of the skin that was localized mainly to the peri-ocular area. Frequent and massive feeding of swarming sucking flies on the lesional sites was witnessed. In every instance (n = 6), Staphylococcus aureus was cultured from the exudate and the aseptically obtained skin biopsy samples from both recurrent and new cases. The main predisposing factor was the presence of small troughs, which forced the sheep to compete for food. Intramuscular administration of cefalexin for 7 days resulted in the resolution of lesions over a 2-week period. No further cases or recurrences were seen over the 16-month follow-up period. The main histopathological feature of this skin disease was a superficial and deep, perivascular to interstitial eosinophilic and mononuclear dermatitis.     

Cytotoxic activity of Origanum dictamnus

Several extracts of Origanum dictamnus, an endemic plant of Greece growing only in the island of Crete and the bioassay-directed isolated ursolic acid, were tested in vitro against the P388 (murine leukemia) and the human bronchial epidermoid cancer NSCLC-N6 (non small cell lung cancer) cell lines. Both the initial dichloromethane extract and the isolated from it ursolic acid exhibited cytotoxic activity. Ursolic acid was also tested in vivo, on murine ascite leukemia P388, where it exhibited at a dose of 50 mg/kg a marginal antileukemic activity.     

Greenhouse biofumigation with <Emphasis Type="Italic">Melia azedarach</Emphasis> controls <Emphasis Type="Italic">Meloidogyne</Emphasis> spp. and enhances soil biological activity

The need for environmentally friendly agricultural practices has led to the development of plant-based nematicides for root-knot nematode control. The efficacy of these botanicals has been tested primarily under laboratory and rarely under actual field conditions. Moreover, any side effects on non-target soil organisms that support soil biological activity are usually ignored. Herein, we evaluate the efficacy of Melia azedarach preparations against Meloidogyne spp. in a tomato greenhouse, by root gall examination and soil J2 enumeration. We also assessed side effects on soil microbes through PLFA analysis and microbivorous nematodes, and we quantified several plant growth parameters (e.g., fruit number and weight, root weight). Different treatments within the greenhouse included M. azedarach ripe fruit powder (MFP), ripe fruit water extract (MWE) and furfural, one of the principal active ingredients of M. azedarach and previously known to exhibit fumigant nematicidal activity. Results were compared to those obtained with the commercial nematicide oxamyl (Vydate^® 10 SL) and an untreated control. All treatments were repeated every 20 days throughout the cultivation period. MFP and MWE suppressed Meloidogyne spp. often at the same levels obtained by furfural and oxamyl treatments and enhanced soil biological activity, as indicated by the proliferation of soil microbes and microbial feeding nematodes. Furfural and oxamyl adversely affected the soil community, especially the free-living nematodes. Moreover, furfural was phytotoxic to tomato plants in spite of its natural origin.     

Male multiple matings and reproductive success in commodity-adapted strains of <Emphasis Type="Italic">Sitophilus oryzae</Emphasis>

Multiple matings occur in many species of stored-grain insect pests, such as the rice weevil Sitophilus oryzae (L.), with both female and male mating more than once and with more than one partner. Multiple female mating in S. oryzae increased lifetime fecundity by extending the period of time progeny were produced, but consequences of multiple male mating in S. oryzae were not yet studied although it is likely to increase male fitness by increasing offspring production. Here, the effects of polygynous mating on male mating behavior, success, and fitness were assessed in two strains of S. oryzae, one adapted to barley and another to wheat. Two insect strains were considered because they may differ in response depending on the host grain, which present distinct nutritional value to the insects. Mating by pairs formed between the two strains did not impact mating success, but wheat-adapted females exhibited longer mating duration, which was positively correlated with progeny production. Wheat-adapted males exhibited higher fertility than barley-adapted males. When male multiple matings were considered in successive polygynous matings, late matings led to lower non-cumulative values of progeny production, but higher cumulative performance, and wheat-adapted S. oryzae always performed better. Thus, male fitness and grain losses in wheat are higher than in barley, even when S. oryzae was adapted to the latter.     

Nitrogen Leaching Of Spring Wheat Genotypes (Triticum Aestivum L.) Varying In Nitrogen-Related Traits

Efficient use of nitrogen (N) by wheat crop and hence prevention of possible contamination of ground and surface waters by nitrates has aroused environmental concerns. The present study was conducted in drainage lysimeters for three years (1998–2000) to identify whether spring wheat genotypes (Triticum aestivum L.) that differ in N-related traits differ in N leaching and to relate parameters of N use efficiency (NUE) with parameters of N leaching. For this reason two spring wheat cultivars (‘Albis’ and ‘Toronit’) and an experimental line (‘L94491’) were grown under low (20 kg N ha^?1) and ample N supply (270 kg N ha^?1). The genotypes varied in parameters of NUE but not in N leaching. Grain yield of the high-protein line (‘L94491’) was, on average, 11% lower than that of ‘Toronit’ but among genotypes had significantly higher N in the grain (%), grain N yield, and N harvest index. Nitrogen lost through leaching was considerably low (0.42–0.52 g m^?2) mainly due to low volume of percolating water or the ability of the genotypes to efficiently exploit soil mineral N. There were no clear relationships between N-related genotype traits and N leaching, but across all treatments significantly negative correlations between volume of leachate and the amount of N in the total biomass and grain N yield existed.