Beef Quality Assurance national rancher survey: program participation, best management practices, and motivations for joining future sustainability programs.

Till date, with over 137,000 certified members, the most successful rancher educational program has been the Beef Quality Assurance (BQA) program. The BQA program was established in the mid-1990's to improve animal health and welfare with a primary objective to reduce the incidence of injection site lesions by instructing producers to administer injections in the neck only. The present study investigated the drivers of this success to inform future rancher education programs around agricultural sustainability. An online multistate survey was administered to cattle ranchers in collaboration with state cattlemen's associations to better understand rancher motivations for adopting new practices and to gain insight on current involvement in BQA. In total, the survey consisted of 45 questions and was divided into 3 sections: (1) rancher demographics, (2) BQA participation and current best management practice (BMP) application, and (3) willingness to join new rancher educational programs. Data from 842 respondents are including in this study. Of the survey participants, 70% were currently BQA certified or had been BQA certified at one time, and 30% had never been certified. Ranchers who were BQA certified at any time were less likely to administer injections in areas other than the neck compared to ranchers who were not certified (P < 0.05), demonstrating the effectiveness of the BQA program. More than 80% of survey respondents who joined the BQA program stated they believed the BQA program improved animal health and welfare on their operation (n = 617). Among those who had not joined the BQA program, 40% believed BQA practices did not align with their ranching operation, while 38% had not heard of the BQA program (n = 256). The survey indicated that male ranchers, those with more years ranching, those with a larger percent of income coming from ranching, and ranches with larger total acres grazed were more likely to be BQA certified at any time (P < 0.05). Finally, ranchers who were BQA certified at any time were more likely to state that joining a rancher sustainability program would be beneficial to their operation. In conclusion, not only did the survey provide valuable insight into BQA program adoption but highlighted how BQA pedagogy and program structure may be a suitable framework for creating future rancher sustainability programs.

Molecular mapping of thrombin-receptor interactions.

In addition to its procoagulant and anticoagulant roles in the blood coagulation cascade, thrombin works as a signaling molecule when it interacts with the G-protein coupled receptors PAR1, PAR3, and PAR4. We have mapped the thrombin epitopes responsible for these interactions using enzymatic assays and Ala scanning mutagenesis. The epitopes overlap considerably, and are almost identical to those of fibrinogen and fibrin, but a few unanticipated differences are uncovered that help explain the higher (90-fold) specificity of PAR1 relative to PAR3 and PAR4. The most critical residues for the interaction with the PARs are located around the active site where mutations affect recognition in the order PAR4 > PAR3 > PAR1. Other important residues for PAR binding cluster in a small area of exosite I where mutations affect recognition in the order PAR1 > PAR3 > PAR4. Owing to this hierarchy of effects, the mutation W215A selectively compromises PAR4 cleavage, whereas the mutation R67A abrogates the higher specificity of PAR1 relative to PAR3 and PAR4. 3D models of thrombin complexed with PAR1, PAR3, and PAR4 are constructed and account for the perturbations documented by the mutagenesis studies.

Determinants of thrombin specificity.

Thrombin recognizes a number of natural substrates that are responsible for important physiologic functions. Its high specificity is controlled by residues within the active site, and by separate recognition sites located on the surface of the enzyme. A number of studies have addressed the question of how thrombin changes its specificity from fibrinogen to protein C, switching from a procoagulant to an anticoagulant enzyme. Site directed mutagenesis studies have revealed important aspects of how this switch takes place. Specifically, residues W215 and E217 have emerged as key residues in controlling the interaction with fibrinogen in that mutation of these residues compromises the procoagulant function of the enzyme up to 500-fold. The loss of fibrinogen clotting reaches 20,000-fold in the double mutant W215A/E217A, whereas protein C activation is compromised less than sevenfold. These findings demonstrate that thrombin specificity can be dissected at the molecular level using Ala-scanning mutagenesis and the procoagulant function of the enzyme can be abrogated rationally and selectively. It is now possible to extend this strategy to the study of other interactions of thrombin, as well as to related serine proteases.

Rational design of a potent anticoagulant thrombin.

Thrombin acts as a procoagulant when it cleaves fibrinogen and promotes the formation of a fibrin clot and functions as an anticoagulant when it activates protein C with the assistance of the cofactor thrombomodulin. The dual function of thrombin in the blood poses the challenge to turn the enzyme into a potent anticoagulant by selectively abrogating fibrinogen cleavage. Using functional and structural data, we have rationally designed a thrombin mutant, W215A/E217A, that cleaves fibrinogen with a value of k(cat)/K(m) about 20,000-fold slower than wild-type but activates protein C in the presence of thrombomodulin with a specificity comparable with wild-type. This mutant demonstrates for the first time that the relative specificity of thrombin toward fibrinogen and protein C can be completely reversed.

Dual role of PKC in modulating pharmacomechanical coupling in fetal and adult cerebral arteries.

This study tested the hypothesis that protein kinase C (PKC) has dual regulation on norepinephrine (NE)-mediated inositol 1,4, 5-trisphosphate [Ins (1,4,5)P(3)] pathway and vasoconstriction in cerebral arteries from near-term fetal ( approximately 140 gestational days) and adult sheep. Basal PKC activity values (%membrane bound) in fetal and adult cerebral arteries were 38 +/- 4% and 32 +/- 4%, respectively. In vessels of both age groups, the PKC isoforms alpha, beta(I), beta(II), and delta were relatively abundant. In contrast, compared with the adult, cerebral arteries of the fetus had low levels of PKC-epsilon. In response to 10(-4) M phorbol 12,13-dibutyrate (PDBu; PKC agonist), PKC activity in both fetal and adult cerebral arteries increased 40-50%. After NE stimulation, PKC activation with PDBu exerted negative feedback on Ins(1,4,5)P(3) and intracellular Ca(2+) concentration ([Ca(2+)](i)) in arteries of both age groups. In turn, PKC inhibition with staurosporine resulted in augmented NE-induced Ins(1,4,5)P(3) and [Ca(2+)](i) responses in adult, but not fetal, cerebral arteries. In adult tissues, PKC stimulation by PDBu increased vascular tone, but not [Ca(2+)](i). In contrast, in the fetal artery, PKC stimulation was associated with an increase in both tone and [Ca(2+)](i). In the presence of zero extracellular [Ca(2+)], these PDBu-induced responses were absent in the fetal vessel, whereas they remained unchanged in the adult. We conclude that, although basal PKC activity was similar in fetal and adult cerebral arteries, PKC's role in NE-mediated pharmacomechanical coupling differed significantly in the two age groups. In both fetal and adult cerebral arteries, PKC modulation of NE-induced signal transduction responses would appear to play a significant role in the regulation of vascular tone. The mechanisms differ in the two age groups, however, and this probably relates, in part, to the relative lack of PKC-epsilon in fetal vessels.

"Who knows the power of his bones". Reburial redux.

This paper discusses the repatriation of human remains to indigenous peoples in Australia and the United States and the role anthropologists play in the construction of past, present, and future identities for contemporary indigenous peoples. Using examples from both countries, I suggest that many of the participants at the reburials, and in the events leading up to them, were not only reburying their dead ancestors and addressing religious concerns, but were also redeeming past social injustices, renegotiating the status quo, and affirming their modern social and religious identity--all important issues for Fourth World peoples living in First World nation-states today. Reburials are powerful social dramas, testimony to the complex historical relationships between and among all concerned, living and dead, indigenous and non-indigenous. I also argue that as Fourth World peoples attempt to renegotiate the status quo by turning to the past and reburying their ancestors, the important role of anthropologists in this effort should be considered in terms of both practice and theory. Because of the combination of heritage/cultural resource management legislation, government regulations, a changing professional ethic in regards to issues of repatriation, anthropologists in all subdisciplines are increasingly involved in the witting and unwitting reproduction of indigenous social orders. The implications of this and its ethical dilemmas for anthropologists working in all the subdisciplines and in varied workplaces are explored. The necessity of working with indigenous communities is underscored and suggestions for working toward a common universal heritage are presented.

The H-mshi antigen is conserved among standard BALB/cBy, C57BL/6J, and wild-derived CAST/Ei and SPRET/Ei inbred strains of mice.

The recessive male sterility and histoincompatibility mutation (mshi) arose spontaneously in the standard inbred mouse strain BALB/cBy. In addition to generating sterility in homozygous males, mshi controls the loss of a minor histocompatibility antigen designated H-mshi. To determine whether the H-mshi antigen normally expressed by the BALB/cBy strain (H-mshi(c)) is the same as or different from the antigen (H-mshi(x)) expressed by the standard inbred C57BL/6J strain or the wild-derived CAST/Ei and SPRET/Ei strains, animals heterozygous for the mutant antigen-loss allele (H-mshi-) and H-mshi(x) were grafted with tail skin from BALB/cBy mice. The long-term retention of grafts by these hosts indicates that the H-mshi antigen encoded by the BALB/cBy, C57BL/6J, CAST/Ei, and SPRET/Ei strains is histogenically identical. Conservation of this minor histocompatibility antigen among these evolutionarily diverse strains suggests that H-mshi encodes a functionally important cellular product(s).

Molecular genetic mapping of the mouse male sterility and histoincompatibility (mshi) mutation on proximal chromosome 10.

The recessive male sterility and histoincompatibility (mshi) mutation in the mouse generates pleiotropic effects on histocompatibility and male reproduction, while female mutants appear to be reproductively normal. We have mapped the mshi mutation to mouse Chromosome (Chr) 10 by analysis of 126 progeny from an intraspecific backcross. Our analysis both places the male sterility and histoincompatibility controlled by mshi within a 20-cM interval between the markers D10Mit51/D10Mit212 and D10Mit170 and has allowed the ordering of several other microsatellite markers on Chr 10 that were previously unresolved. The high-resolution backcross panel we describe should facilitate the isolation of more tightly linked probe sequences and, ultimately, the molecular identification of the gene or genes affected by this interesting mutation.