Abstract. The aims of the present study were to clarify the effect of kisspeptin-10 (Kp10) on the secretion of luteinizing hormone (LH), follicle-stimulating hormone (FSH) and growth hormone (GH) in prepubertal male and female cattle. The experiments were performed from May to June using five male (4-6 months old) and five female (5-6 months old) Japanese Black calves. A single intravenous (iv) injection of Kp10 (5 μg/kg body weight (b.w.): 3.85 nmol/ kg b.w.)significantly stimulated the release of LH and FSH in male and female calves (P<0.05). A single intramuscular injection of Kp10 (5 μg/kg b.w.) also significantly stimulated the release of LH and FSH in male calves (P<0.05), though the response was smaller than that to the iv injection. The injection of Kp10 did not alter the basal plasma concentration of GH in male or female calves. The area under the curve (AUC) of both LH and FSH for a 120-min period after the iv injection of Kp10 was significantly greater in the males than females (P<0.05). These results show that Kp10 can stimulate the release of LH and FSH in calves of both sexes and that the response to the peptide is greater in males at this age. They also show that Kp10 has no effect on the release of GH in male and female calves and that the LH-and FSHreleasing effect of Kp10 is greater after an iv injection than after an im injection in calves. Key words: Cattle, Follicle-stimulating hormone (FSH), Growth hormone (GH), Kisspeptin-10, Luteinizing hormone (LH) (J. Reprod. Dev. 55: 650-654, 2009) he pituitary's release of gonadotropins, luteinizing hormone (LH) and follicle-stimulating hormone (FSH), is essential to normal gonadal development and function [1], such as ovulation in females and spermatogenesis in males [2]. The brain-pituitarygonadal axis is operated by the decapeptide gonadotropin-releasing hormone (GnRH) in the mammalian brain. However, recently, the KiSS-1/GPR54 system in the hypothalamus was implicated in the regulation of this axis [3][4][5].Kisspeptin is the product of the KiSS-1 gene, which encodes a 145-amino acid peptide that is further processed to generate biologically active peptides of various lengths (10-54 amino acids) termed kisspeptins [5,6]. Kisspeptin neurons are found in the hypothalamus [7][8][9], and kisspeptins strongly stimulate the secretion of gonadotropin through a G protein-coupled receptor known as GPR54 [3][4][5]. The actions of these peptides are thought to involve mainly stimulating GnRH's neuronal activity through GPR54 [3][4][5].An administration of kisspeptin, either centrally or peripherally, has been shown to elicit the release of gonadotropins in ruminants [10][11][12][13][14][15] as well as in rats [16,17], pigs [18], monkeys [19] and humans [20,21]. However, in cattle, only two in vivo studies have been conducted [13,14], and the precise effects of kisspeptin on the secretion of pituitary hormones under physiological conditions are unknown.Puberty as a successful reproductive event is closely related to interactions between the gonadotropic axis ...

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Chromium (Cr) is a toxic heavy metal that contaminates soil and water resources after its discharge from different industries. A pot experiment was conducted to determine the effects of single and/or combined application of sodium nitroprusside (SNP) (250 μM) and sodium hydrogen sulfide (NaHS) (1 mM) on growth, photosynthetic pigments, gas exchange characteristics, oxidative stress biomarkers, antioxidant machinery (enzymatic and non-enzymatic antioxidants), ion uptake, organic acid exudation, and Cr uptake of spinach (Spinacia oleracea L.) exposed to severe Cr stress [Cr: 0 (no Cr), 150, and 300 μM]. Our results depicted that Cr addition to the soil significantly (P &lt; 0.05) decreased plant growth and biomass, gas exchange attributes, and mineral uptake by S. oleracea when compared to the plants grown without the addition of Cr. However, Cr toxicity boosted the production of reactive oxygen species (ROS) by increasing the content of malondialdehyde (MDA), which is the indication of oxidative stress in S. oleracea, and was also manifested by hydrogen peroxide (H2O2) content and electrolyte leakage to the membrane-bound organelles. The results showed that the activities of various antioxidative enzymes, such as superoxidase dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX), and the content of non-enzymatic antioxidants, such as phenolic, flavonoid, ascorbic acid, and anthocyanin, initially increased with an increase in the Cr concentration in the soil. The results also revealed that the levels of soluble sugar, reducing sugar, and non-reducing sugar were decreased in plants grown under elevating Cr levels, but the accumulation of the metal in the roots and shoots of S. oleracea, was found to be increased, and the values of bioaccumulation factor were &lt;1 in all the Cr treatments. The negative impacts of Cr injury were reduced by the application of SNP and NaHS (individually or combined), which increased plant growth and biomass, improved photosynthetic apparatus, antioxidant enzymes, and mineral uptake, as well as diminished the exudation of organic acids and oxidative stress indicators in roots of S. oleracea by decreasing Cr toxicity. Here, we conclude that the application of SNP and NaHS under the exposure to Cr stress significantly improved plant growth and biomass, photosynthetic pigments, and gas exchange characteristics; regulated antioxidant defense system and essential nutrient uptake; and balanced organic acid exudation pattern in S. oleracea.

Soil contamination with toxic heavy metals [such as lead (Pb)] is becoming a serious global problem due to the rapid development of the social economy. However, accumulation of Pb in plant parts is very toxic for plant growth and decreases crop yield and productivity. In the present study, we have investigated the different concentrations of Pb in the soil i.e., [0 (no Pb), 50, and 100 mg kg–1] to study plant growth and biomass, photosynthetic pigments and gas exchange characteristics, oxidative stress indicators and the response of various antioxidants (enzymatic and non-enzymatic), nutritional status of the plant, organic acid exudation pattern and also Pb accumulation in the roots and shoots of the plants of two varieties of tomato (Solanum lycopersicum L.) i.e., Roma and Cchuas, grown under different levels of synergic acid [no spray (NS), water spray (WS), 0.3-0.5°μM]. Results from the present study showed that the increasing levels of Pb in the soil decreased non-significantly (P &lt; 0.05) shoot length, root length, shoot fresh weight, root fresh weight, shoot dry weight, root dry weight, chlorophyll-a, chlorophyll-b, total chlorophyll, carotenoid content, net photosynthesis, stomatal conductance, transpiration rate, soluble sugar, reducing sugar, non-reducing sugar contents, calcium (Ca2+), magnesium (Mg2+), iron (Fe2+), and phosphorus (P) contents in the roots and shoots of the plants. However, Pb toxicity also induced oxidative stress in the roots and shoots of the plants by increasing malondialdehyde (MDA), hydrogen peroxide (H2O2), and electrolyte leakage (EL) which also induced increased the compounds of various enzymatic and non-enzymatic antioxidants and also organic acids exudation pattern in the roots such as fumaric acid, acetic acid, citric acid, formic acid, malic acid, oxalic acid contents and increased the concentration of Pb in different parts of the plants. Results also show that the Cchuas showed better growth and development compared to Roma, under the same levels of Pb in the soil. The alleviation of Pb toxicity was induced by the application of synergic acid, and results showed that the application of synergic acid increased plant growth and biomass and also increased the gas exchange characteristics and antioxidant capacity in the roots and shoots of the plants. Research findings, therefore, suggested that synergic acid application can ameliorate Pb toxicity in S. lycopersicum varieties and result in improved plant growth and composition under metal stress as depicted by balanced exudation of organic acids.

Phytoremediation is an ecofriendly technique to clean heavy metals from contaminated soil by the use of high biomass producing plant species. Chelators can help to improve this biological technique by increasing metal solubility. Therefore, a pot experiment was conducted to determine the effect of the chelators EDTA and citric acid (CA) in phytoremediation of Ni contaminated soil by using Brassica napus (canola). Two cultivars of B. napus, Con-II (tolerant) and Oscar (sensitive), were selected after screening and exposed to NiSO4 at 30 ppm at the time of sowing. CA (10 mM) and EDTA (1.5 mM) were applied either alone or in combination with each other after two weeks of Ni treatments. Different parameters like morpho-physiological and biochemical data were recorded after 15 days of chelate application. The results highlighted the successful use of chelating agents (CA and EDTA) not only to ameliorate Ni stress but also to enhance Ni accumulation which is prerequisite for phytoremediation. The basal application of 10 mMCA and 1.5 mM EDTA concentration proved to be effective for the growth of plants. The combination of chelating agents failed to show any synergistic effects.

Drought is one of the most damaging abiotic stress that hinder plant growth and development. The present study aimed to determine the effects of various Ca/Mg quotients under polyethylene glycol (PEG)–induced osmotic stress on growth, uptake and translocation of Ca and Mg in Avena sativa (L). Plants were grown in nutrient solution supplemented with three different Ca/Mg molar quotients (0.18, 2, and 4). After 30 days plants were exposed to two different PEG (Polyethylene glycol) concentrations (0.6 MPa & 0.2 MPa) for 8 days, and solutions were renewed after 4 days. A solution containing Ca and Mg nutrients has mitigated the negative impact caused via osmotic stress on relative growth rate (RGR), absolute growth rate (AGR), crop growth rate (CGR), leaf area ratio (LAR), Leaf index ratio (LAI), root-shoot ratio (RSR), water use efficiency (WUE) and net assimilation rate (NAR). In addition, it adversely affected germination parameters, including final emergence percentage (FEP), mean germination time (MGT), Timson germination Index (TGI), germination rate index (GRI) and percent field capacity (%FC), of oat (Avena sativa L.). Mg and Ca in shoot and root and Ca translocation factor decreased with increasing Ca in solution, while Mg translocation factor increased with increasing Ca in nutrient solution. In this work, the combined effects of various Ca/Mg quotients and osmotic stress produced by polyethylene glycol (PEG) in different concentrations (0.6 MPa, 0.2 MPa) on the growth and element uptake of Avena sativa L. are examined. As a result, the Ca/Mg Quotient may naturally combat the moderate drought stress experienced by field crops.

Fungal and mycotoxin contamination of milk products constitute a potential hazard to human health and food safety. Isolation and identifications of mold and yeast out of 140 milk products samples collected from dairy shops in Qena, Egypt were done through conventional microbiological methods. Aflatoxin-M1, aflatoxin-B1 and ochratoxin-A were characterized by thin-layer chromatography; aflR regulatory gene identified by using PCR. Marine algal extracts of Halimeda opuntia, Padina pavonica and Turbinaria decurrens species were studied for their antimicrobial activity. Overall of 80 and 64% dairy products samples were positive for mold and yeast contamination. A total of 38 mold and 15 yeast species were isolated. Aspergillus and Candida spp. were the most abundant isolated species. Furthermore 25, 40 and 27% of cheese and 71, 78 and 73.3 of dairy desserts samples were contaminated with AFM1, AFB1 and OTA, respectively; with average estimated dietary intake level much more than the acceptable daily intake for infant and adult. PCR identified aflR gene among four selected aflatoxigenic A. flavus. The major constituents of H. opuntia extract were 2,4-Decadienal, (E,E)-(21.56%) and 9,12-Octadecadienoic acid (Z,Z)-(36.16%). Ethyl acetate extract of Halimeda opuntia (3mg/ml) exhibited the strongest fungicidal activity with inhibition zones of 16.5 and 22.3 mm against A. flavus and A. niger. It exhibited potent candidacidal activity against C. tropicalis; 11 log10 orders of killing at 750 µg/ml. The discovered antimicrobial activity of H. opuntia is a promising candidate for designing novel antifungal agents which can be used in food preservatives and medicine industry.