Antibody-catalyzed porphyrin metallation

An antibody elicited to a distorted N-methyl porphyrin catalyzed metal ion chelation by the planar porphyrin. At fixed Zn2+ and Cu2+ concentrations, the antibody-catalyzed reaction showed saturation kinetics with respect to the substrate mesoporphyrin IX (2) and was inhibited by the hapten, N-methylmesoporphyrin IX (1). The turnover number of 80 hour-1 for antibody-catalyzed metallation of 2 with Zn2+ compares with an estimated value of 800 hour-1 for ferrochelatase. The antibody also catalyzed the insertion of Co2+ and Mn2+ into 2, but it did not catalyze the metallation of protoporphyrin IX (3) or deuteroporphyrin IX (4). The antibody has high affinity for several metalloporphyrins, suggesting an approach to developing antibody-heme catalysts for redox or electron transfer reactions.     

Pregnancy Rates in Angus Cross Beef Cows Bred at Observed Oestrus With or Without Second GnRH Administration in Fixed‐Time Progesterone‐Supplemented Ovsynch and CO‐Synch Protocols

Crossbred cows (n = 1073) from five locations had oestrous cycles synchronized with 100 μg of GnRH IM and insertion of controlled internal drug release device (CIDR) on Day 0 followed by 25 mg of PGF_2α IM and CIDR removal on Day 7. Kamar^® patches were placed on all cows at CIDR removal. Cows were observed three times daily for oestrus after PGF_2α administration. In the Ovsynch‐CIDR group, cows detected in oestrus (n = 193) within 48 h after PGF_2α were inseminated using the AM–PM rule. Among these cows, 80 received and 113 did not receive a second GnRH at 48 h after PGF_2α. Cows (n = 345) not detected in oestrus received a second GnRH at 48 h after PGF_2α on Day 9, and fixed‐time AI 16 h after the GnRH on Day 10. In the CO‐Synch‐CIDR group, cows detected in oestrus (n = 224) within 48 h after PGF_2α were inseminated using the AM–PM rule. Among these cows, 79 received and 145 did not receive a second GnRH at 64 h after PGF_2α. Cows (n = 311) not detected in oestrus received a second GnRH on Day 10 at the time of AI, 64 h after PGF_2α. The AI pregnancy rates were not different between the Ovsynch‐CIDR and CO‐Synch‐CIDR groups (p = 0.48). There were no differences in the AI pregnancy rates for cows inseminated at a fixed time (p = 0.26) or at detected oestrus (p = 0.79) between the treatment groups. Among cows inseminated in oestrus, there were no differences in the AI pregnancy rates between cows that received or did not receive the second GnRH (p = 0.47). In conclusion, acceptable AI pregnancy rates can be achieved with or without inclusion of oestrus detection in the Ovsynch‐CIDR and CO‐Synch‐CIDR protocols. Among cows detected in oestrus, cows that received a second GnRH yielded similar pregnancy rates when compared with cows that did not receive the second GnRH.     

Fertility of Angus cross beef heifers after GnRH treatment on day 23 and timing of insemination in 14‐day CIDR protocol

This study compared artificial insemination pregnancy rate (AI‐PR) between 14‐day CIDR‐GnRH‐PGF2α‐GnRH and CIDR‐PGF2α‐GnRH synchronization protocol with two fixed AI times (56 or 72 hr after PGF2α). On day 0, heifers (n = 1311) from nine locations assigned body condition score (BCS: 1, emaciated; 9, obese), reproductive tract score (RTS: 1, immature, acyclic; 5, mature, cyclic) and temperament score (0, calm; and 1, excited) and fitted with a controlled internal drug release (CIDR, 1.38 g of progesterone) insert for 14 days. Within herd, heifers were randomly assigned either to no‐GnRH group (n = 635) or to GnRH group (n = 676), and heifers in GnRH group received 100 μg of GnRH (gonadorelin hydrochloride, IM) on day 23. All heifers received 25 mg of PGF2α (dinoprost, IM) on day 30 and oestrous detection aids at the same time. Heifers were observed for oestrus thrice daily until AI. Within GnRH groups, heifers were randomly assigned to either AI‐56 or AI‐72 groups. Heifers in AI‐56 group (n = 667) were inseminated at 56 hr (day 32 PM), and heifers in AI‐72 group (n = 644) were inseminated at 72 hr (day 33 AM) after PGF2α administration. All heifers were given 100 μg of GnRH concurrently at the time AI. Controlling for BCS (p < .05), RTS (p < .05), oestrous expression (p < .001), temperament (p < .001) and GnRH treatment by time of insemination (p < .001), the AI‐PR differed between GnRH treatment [GnRH (Yes – 60.9% (412/676) vs. No – 55.1% (350/635); p < .05)] and insemination time [AI‐56 – 54.6% (364/667) vs. AI‐72 – 61.8% (398/644); (p < .01)] groups. The GnRH treatment by AI time interaction influenced AI‐PR (GnRH56 – 61.0% (208/341); GnRH72 – 60.9% (204/335); No‐GnRH56 – 47.9% (156/326); No‐GnRH72 – 62.8% (194/309); p < .001). In conclusion, 14‐day CIDR synchronization protocol for FTAI required inclusion of GnRH on day 23 if inseminations were to be performed at 56 hr after PGF2α in order to achieve greater AI‐PR.     

Lamellar pro-inflammatory cytokine expression patterns in laminitis at the developmental stage and at the onset of lameness: innate vs. adaptive immune response

REASONS FOR PERFORMING STUDY: Recent research has indicated that inflammation plays a role in the early stages of laminitis and that, similar to organ failure in human sepsis, early inflammatory mechanisms may lead to downstream events resulting in lamellar failure. Characterisation of the type of immune response (i.e. innate vs. adaptive) is essential in order to develop therapeutic strategies to counteract these deleterious events. OBJECTIVES: To quantitate gene expression of pro-inflammatory cytokines known to be important in the innate and adaptive immune response during the early stages of laminitis, using both the black walnut extract (BWE) and oligofructose (OF) models of laminitis. METHODS: Real-time qPCR was used to assess lamellar mRNA expression of interleukins-1beta, 2, 4, 6, 8, 10, 12 and 18, and tumour necrosis factor alpha and interferon gamma at the developmental stage and at the onset of lameness. RESULTS: Significantly increased lamellar mRNA expression of cytokines important in the innate immune response were present at the developmental stage of the BWE model, and at the onset of acute lameness in both the BWE model and OF model. Of the cytokines characteristic of the Th1 and Th2 arms of the adaptive immune response, a mixed response was noted at the onset of acute lameness in the BWE model, whereas the response was skewed towards a Th1 response at the onset of lameness in the OF model. CONCLUSIONS: Lamellar inflammation is characterised by strong innate immune response in the developmental stages of laminitis; and a mixture of innate and adaptive immune responses at the onset of lameness. POTENTIAL RELEVANCE: These results indicate that anti-inflammatory treatment of early stage laminitis (and the horse at risk of laminitis) should include not only therapeutic drugs that address prostanoid activity, but should also address the marked increases in lamellar cytokine expression.     

The effect of N placement on grass weeds and winter wheat responses in three tillage systems

Field studies were conducted for three seasons (1978–1979, 1979–1980 and 1981–1982) on a Palouse silt loam near Pullman, Washington, to compare the effects of broadcast and deep banding of nitrogen (N) fertilizer beneath winter wheat (Triticum aestivum L.) seed on N uptake and dry matter production of downy brome (Bromus tectorum L.) and jointed goatgrass (Aegilops cylindrica Host.), and on N uptake, dry matter production and grain yields of winter wheat. Three tillage systems were used: conventional tillage; shallow roto-tilling, or no-tillage prior to planting. Rates of N were 0, 65, 130 and 190 kg N ha⁻¹ as ammonium nitrate. Additional plots were maintained free of weeds at the 130 kg N ha⁻¹ rate. In 1983–1984, deep banding of the fertilizer between rows in a paired-row configuration was compared to surface-broadcast N fertilizer using N rates of 0, 45, 90 and 135 kg N ha⁻¹. There were no significant differences between broadcast and deep-band application of N on grass weed N uptake or dry matter production with mold-board plowed or no-tillage, but there was greater weed growth with surface-broadcast N with shallow roto-tilling. Wheat N uptake, growth and grain yields were consistently higher with band-applied N compared to broadcast N. The yield response to banding N was the same with or without the presence of grass weeds.     

Sectional notes

American Journal of Potato Research -