Interrelationships among physicochemical properties, absorption and anthelmintic activities of 2-desoxoparaherquamide and selected analogs

The interrelationships between physicochemical properties, absorption and potency of 2-desoxoparaherquamide and five analogs, representing a new anthelmintic class, were evaluated in in vitro and in vivo assays. At pH 7.5, rates of drug absorption by the gastrointestinal nematode Haemonchus contortus and jird small intestine, parameterized by the permeability coefficient, P(e), ranged from 1.2-2.4 x 10(-4) cm/min (nematode) to 2.5-5.5 x 10(-3) cm/min (jird). In the jird intestine, absorption was pH-dependent, with P(e) at pH 7.5 being twice that at pH 4.5, reflecting the negative influence of protonation on transport of these weakly basic molecules. Each compound rapidly paralyzed H. contortus during in vitro exposure to therapeutically relevant concentrations (1-10 microm). The kinetics of drug action on motility in vivo mirrored their in vitro effects; motility concentrations were reduced in nematodes collected from jird stomach 3 h following oral drug dosing, by which time > or =50% clearance of the parasites had occurred. The nematode/medium partition coefficient K ranged from 10.1 to 16.1, consistent with the lipophilic nature of the compounds. The time required to reduce motility in vitro by 50% (t50*) and P(e) were used to determine C(n)*, the concentration of drug in the nematode at t50*, as an indicator of intrinsic potency. In the jird, the apparent potencies of the compounds were insensitive to route of administration (i.e. oral = i.v. = i.p. = i.m.) for H. contortus and two other gastrointestinal nematodes, Ostertagia ostertagi and Trichostrongylus colubriformis; topical administration, however, required three to 10-fold higher doses for equivalent efficacy.     

Relationship between early post-mortem muscle pH and shortening-induced toughness in the Pectoralis major muscle of processed broilers air-chilled at 0 degrees C and -12 degrees C

1. An experiment was conducted to investigate the development of shortening-induced toughness in the Pectoralis major (PM) muscles of commercially processed broilers, air-chilled at 0 degrees C and -12 degrees C, as a function of muscle pH early post-mortem. Electrical stimulation was used immediately after stunning and neck cutting to provide carcases with pH values 15 min post-mortem (pH15 min) ranging between 6.79 and 5.85. 2. The deep PM muscle temperatures of carcases chilled at -12 degrees C were lower (cooler) after primary chilling and at 215 min post-mortem than those chilled at 0 degrees C, although chilling regimen had no major effect on pH values over the 24 h post-mortem period. However, carcases chilled at -12 degrees C had longer sarcomeres, lower cooking losses and lower shear force values than those chilled at 0 degrees C. 3. Correlation analysis of the results for both chilling regimens clearly demonstrated that over the pH15min range 6.79 to 5.85, carcases with the lowest pH15min values had the shortest sarcomeres, the highest cooking losses and the toughest meat. In addition, there was no evidence to support the occurrence of cold shortening within this population. This suggests that an early onset of rigor at higher temperatures in broiler carcases, as well as inducing rigor shortening and toughness, might also induce greater protein denaturation and subsequent loss of water holding capacity as manifested in increased cooking losses. 4. Quadratic regression curves showed that over the pH15min range 6.80 to 6.30, only the fast chilling regimen at -12 degrees C could inhibit rigor shortening and minimise changes in cooking loss and shear force values. However, neither chilling regimen was effective in preventing severe rigor shortening, increased cooking losses and adverse toughness in carcases with pH15min values below 6.30. 5. The benefits of fast chilling carcases with pH15min values above 6.3 can also be quantified in terms of carcases exceeding a 4.00 kg/cm2 toughness threshold. Only 1.9% of these carcases chilled at -12 degrees C exceeded this limit (maximum shear force value of 4.72 kg/cm2) compared to 34.9% of the carcases chilled at 0 degrees C (maximum shear force value of 8.46 kg/cm2), further emphasising the considerable reduction in textural variability and improvement in tenderness gained by fast air-chilling at -12 degrees C.     

Role of melanopsin in circadian responses to light

Melanopsin has been proposed as an important photoreceptive molecule for the mammalian circadian system. Its importance in this role was tested in melanopsin knockout mice. These mice entrained to a light/dark cycle, phase-shifted after a light pulse, and increased circadian period when light intensity increased. Induction of the immediate-early gene c-fos was observed after a nighttime light pulse in both wild-type and knockout mice. However, the magnitude of these behavioral responses in knockout mice was 40% lower than in wild-type mice. Although melanopsin is not essential for the circadian clock to receive photic input, it contributes significantly to the magnitude of photic responses.     

“华杂4号”油菜试验示范及特征特性研究

试验和示范证明 ,引进的新品种“华杂 4号”具有优质、高产、多抗的优良综合性状 ,是信阳市发展农业产业化的优质油菜杂交品种之一 ,提出了在信阳市种植“华杂 4号”高产栽培的关键技术措施     

Mitochondrion-rich cells distribution,Na<Superscript>+</Superscript>/K<Superscript>+</Superscript>-ATPase activity and gill morphometry of the Amazonian freshwater stingrays (Chondrichthyes: Potamotrygonidae)

Detailed measurements of gill area and constituent variables (total filament number, total filament length and mean filament length), and immunolocalization of the α-subunit of Na⁺/K⁺-ATPase and Na⁺/K⁺-ATPase activity were performed on both hemibranchs of all five arches of freshwater potamotrygonid stingrays (Paratrygon aiereba and Potamotrygon sp.). Both species exhibit similar mass-specific gill area, 89.8 ± 6.6 and 91.5 ± 4.3 mm² g⁻¹ for P. aiereba and Potamotrygon sp., respectively. The density of Na⁺/K⁺-ATPase-rich MRCs and Na⁺/K⁺-ATPase activity was higher in the 4th gill arch in both species. The Na⁺/K⁺-ATPase activity was positively correlated to the Na⁺/K⁺-ATPase-rich (Na⁺/K⁺-ATPase rich) mitochondrion-rich cell (MRC) distribution among the gill arches of P. aiereba but not in Potamotrygon sp. The levels Na⁺/K⁺-ATPase activity were not correlated to the gill surface area among the arches for both rays’ species. Considering that the Na⁺/K⁺-ATPase-rich MRC is the main site for active ion transport in the gill epithelia and Na⁺/K⁺-ATPase activity plays a crucial role in osmoionoregulatory function, we suggesting that 4th gill arch is more relevant for osmoregulation and ion balance in these potamotrygonids.     

Necrotic enteritis in collared (Pecari tajacu) and white-lipped (Tayassu pecari) peccaries

An outbreak of necrotic enteritis caused by Clostridium perfringens type C was diagnosed in captive collared (Pecari tajacu) and white-lipped (Tayassu pecari) peccaries housed in the Laboratory of Applied Ethology of Universidade Estadual de Santa Cruz located in Ilhéus, State of Bahia, Brazil. Four collared peccaries and three white-lipped peccaries, all juveniles (25-105 days old), were affected. For all affected animals, lethargy and inappetance were followed by sudden death within 24 hours. Histopathology of intestinal wall, culture of C. perfringens type C, and the identification of beta-toxin from intestinal content confirmed the diagnosis.     

茄子夏秋防虫网覆盖栽培技市

茄子是夏秋主要蔬菜之一，但夏秋栽培易发生各种病虫害，特别是近年来随着设施园艺的发展，温室、连栋大棚、大棚等设施周年生产，白粉虱、烟粉虱等病虫害发生加重，防治难度加大，大量用药普遍，不但增加成本，还严重影响茄子的品质。为解决这一问题，2005—2007年我市推广茄子夏秋季防虫网覆盖栽培技术，取得了较理想的效果，而且生产出了A级绿色产品。现将该技术介绍如下：