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PubMed1998

Health examinations and clinical diagnostic procedures of ratites.

It is important to remember when performing health examinations and clinical diagnostic procedures on ratites that all protocols mentioned in this article should be followed; this includes reviewing history, environmental evaluation, proper handling, complete hands-on physical examination, diagnostic testing, and postmortem examination. The individual ratite examination is becoming rare, but veterinarians and producers must remember that individual birds make up the flock. Flock health is maintained by diagnosing disease and health problems early in the most susceptible animals. The most successful producers will use veterinarians as a major element to their management program to raise the most desirable birds for the future of the industry.

Animals↗
PubMed1998

Ratite reproduction.

The role of the veterinarian in ostrich production in the future will be to develop least-cost management programs. This article focuses on the ostrich as the only current commercially viable ratite species. Managing a successful ranch involves disease prevention, genetic selection, environmental management, and nutrition.

Animals↗
PubMed2000

Periosteal bone growth rates in extant ratites (ostriche and emu). Implications for assessing growth in dinosaurs.

The first quantitative experimental data on growth dynamics of the primary cortical bone of young ratites demonstrate the following. 1) From hatching to 2 months of age, cortical thickness remains constant, thereby expressing equilibrium between periosteal bone deposition and an endosteal bone resorption. 2) Radial growth rates of the diaphyseal bone cortex are high (10-40 microns.day-1 on average--maximum 80 microns.day-1) in the hindlimb (femur, tibiotarsus and tarsometatarsus). Wing bones are smaller and later developed. They have lower rates of radial osteogenesis (2-14 microns.day-1). 3) High growth rates are linked to densely vascularized primary bone belonging to the reticular or laminar tissue types. Growth rates fall when bone vascular density decreases. These results emphasize the importance of examining a large number of skeletal elements in order to build a precise knowledge of the general relationship between bone growth rate and bone tissue type. They also stress the potential of bone growth rate quantification among extinct tetrapods, including non-avian dinosaurs.

Animals↗
PubMed2003

Young's modulus varies with differential orientation of keratin in feathers.

Feathers are composed of a structure that, whilst being very light, is able to withstand the large aerodynamic forces exerted upon them during flight. To explore the contribution of molecular orientation to feather keratin mechanical properties, we have examined the nanoscopic organisation of the keratin molecules by X-ray diffraction techniques and have confirmed a link between this and the Young's modulus of the feather rachis. Our results indicate that along the rachis length, from calamus to tip, the keratin molecules become more aligned than at the calamus before returning to a state of higher mis-orientation towards the tip of the rachis. We have also confirmed the general trend of increasing Young's modulus with distance along the rachis. Furthermore, we report a distinct difference in the patterns of orientation of beta-keratin in the feathers of flying and flightless birds. The trend for increased modulus along the feathers of volant birds is absent in the flightless ostrich.

Animals↗
PubMed2001

Gas exchange and energy metabolism of the ostrich (Struthio camelus) embryo.

We measured oxygen consumption (V(O(2))) and carbon dioxide emission (V(CO(2))) rates, air-cell gas partial pressures of oxygen (P(A)O(2)) and CO(2) (P(A)CO(2)), eggshell water vapour conductance and energy content of the ostrich (Struthio camelus) egg, 'true hatchling' and residual yolk, and calculated RQ and total oxygen consumption (V(O(2)tot)) for ostrich eggs incubated at 36.5 degrees C and 25% relative humidity. The V(O(2)) pattern showed a drop of approximately 5% before internal pipping. V(O(2)) just prior to internal pipping agrees with allometric calculations. Despite the higher incubation temperature compared to other studies, and the resultant shorter incubation duration (42 days), V(O(2)tot) (91.7 l kg(-1)) was similar to a previously reported value. RQ values during the second half of incubation (approx. 0.68) were lower than expected for lipid catabolism. Prior to internal pipping, P(A)O(2) and P(A)CO(2) were 98 and 48.3 torr (13.1 and 6.4 kPa), respectively. The growth pattern of the ostrich embryo is different from the typical precocial pattern, showing a time delay in the rapid growth phase. As a result, the lowered overall energy expenditure for tissue maintenance, as compared to other species, is reflected in the low yolk utilization and high residual yolk fraction of the whole hatchling dry mass. These could also result from the relatively short incubation period of the ostrich egg, thereby evading desiccation by excess water loss.

Animals↗
PubMed2003

Does the ostrich (Struthio camelus) coprodeum have the electrophysiological properties and microstructure of other birds?

The ostrich is unique among birds in having complete separation of urine and faeces. The coprodeal epithelium is thus during dehydration exposed to a fluid 500 mOsm hyperosmotic to plasma. We have investigated whether the coprodeum is adapted like a mammalian bladder. The coprodeal epithelium was studied by electrophysiology in the Ussing chamber, and the anatomy by light microscopy and scanning electron microscopy. ELECTROPHYSIOLOGY: The short-circuit current (SCC) and open circuit electrical potential difference were recorded. The change induced by 0.1 mmol mucosal amiloride was recorded. An average basal SCC of 162+/-29 microA/cm(2) was observed, and a resistance of 297+/-34 Omega cm(2) calculated. These values are as observed in other avian coprodea. The resistance is much lower than in mammalian bladders (10000 Omega cm(2)). The amiloride-sensitive SCC, equal to net sodium absorption, was approximately 5 micromol/cm(2)h as observed in other avian species. ANATOMY: The mucosal membrane is composed of broad irregular folds with very short intestinal glands containing an unusually high proportion of goblet cells. CONCLUSION: The ostrich coprodeum is not adapted like a mammalian bladder. The abundance of goblet cells results in a copious secretion of mucus that establishes a thick unstirred layer giving effective osmotic protection.

Animals↗
PubMed2001

Purification and partial characterisation of alpha(2)-antiplasmin and plasmin(ogen) from ostrich plasma.

This study reports the isolation and partial characterisation of the ostrich serpin, alpha(2)AP, and its target enzyme, ostrich plasmin, in its active and inactive proenzyme, namely plasminogen, forms. Ostrich alpha(2)AP was purified using L-lysine-Sepharose chromatography, ammonium sulfate fractionation, and Super Q-650S and ostrich LBSI-Sepharose chromatographies. It revealed a M(r) of 84 K (thousand) and had one and two N-terminal amino acids in common with 11 of those of human and bovine alpha(2)AP, respectively. It showed the largest inhibitory effect on ostrich plasmin, followed by bovine trypsin and plasmin, respectively, and much less plasmin inhibition than bovine aprotinin, but much more so than human alpha(2)AP, DFP and EACA. Ostrich plasminogen was highly purified after L-lysine-Sepharose chromatography and showed a M(r) of 92 K, a total of 775 amino acids and its N-terminal sequence showed approximately 53% identity with those of human, rabbit, cat, and ox plasminogens. Ostrich plasmin, obtained by the urokinase-activation of ostrich plasminogen, revealed a M(r) of 78 K, a total of 638 amino acids, an N-terminal sequence showing two to four residues identical to five of those of human, cat, dog, rabbit, and ox plasmins, and pH and temperature optima of 8.0 and 40 degrees C, respectively.

Amino Acid Sequence↗
PubMedDate not supplied

Purification and characterization of ostrich prothrombin.

The work focused on the penultimate enzyme, prothrombin, in the coagulation cascade. Prothrombin was purified and characterized from ostrich plasma. The results obtained contribute to a better understanding of blood coagulation in the ostrich and the evolution of prothrombin and the coagulation cascade. Prothrombin was purified from ostrich plasma by barium chloride precipitation, ammonium sulfate fractionation, and DEAE-cellulose and Cu(2+)-chelate Sepharose chromatography. Ostrich prothrombin exhibited a M(r) of 72,800 and a pI of 6.9 using SDS-PAGE and PAG-isoelectrofocusing, respectively. The N-terminal sequence of ostrich prothrombin showed 78 and 87% identity with human and bovine, respectively. The cDNA was isolated from ostrich liver and the predicted amino acid sequence compared with those from other species. Ostrich prothrombin shares sequence identity with chicken (84%), human (60%), bovine (59%), rat (60%), mouse (59%) and hagfish (50%) prothrombin, suggesting a common function of prothrombin in these vertebrates. Amino acid sequence identities indicate that the thrombin beta-chain (62%) and the propeptide-Gla (75%) domains are the regions most constrained for the common functions of vertebrate prothrombins. Ostrich prothrombin, therefore, shows similarity in structure to other vertebrate prothrombins.

Amino Acid Sequence↗
PubMed2002

The purification and characterisation of m-calpain from ostrich brain.

Calpains are intracellular cysteine proteases activated in a Ca(2+)-dependent manner. The purpose of the present study was to investigate the physico-chemical and kinetic properties of ostrich brain m-calpain. m-Calpain was purified by successive chromatographic steps on Toyopearl-Super Q 650s and Pharmacia Mono Q HR 5/5 columns. A Ca(2+) concentration of 5mM and a casein concentration of 5mg/ml were found to be necessary for optimum calpain activity. Ostrich m-calpain exhibited a M(r) of 84K using SDS-PAGE and a M(min) of 79.3K from amino acid analysis. The pH and temperature optima were found to be 7.5 and 37 degrees C, respectively. The amino acid composition of m-calpain revealed 700 residues. The N-terminal sequence of m-calpain showed sequence identity with chicken (27%), human (23%) and rabbit (18%) and Schistoma mansoni (9%).

Amino Acid Sequence↗
PubMed2002

The purification and characterization of mu-calpain and calpastatin from ostrich brain.

Calcium-activated neutral proteinases (CANPs) and their endogenous specific inhibitor calpastatin are found in a wide variety of vertebrate and invertebrate tissues. The CANPs are cysteine proteinases that have an absolute requirement for Ca(2+) for activity. mu-Calpain and calpastatin were purified by successive chromatographic steps on Toyopearl-Super Q 650S and Pharmacia Mono Q HR 5/5 columns. The enzyme has a M(r) of 84KDa using sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE), a M(min) of 79KDa from amino acid analysis and an pI of 5.2. Calpastatin has a M(r) of 323KDa using denaturing gradient PAGE and a pI of 4.7. The amino acid composition of mu-calpain revealed 689 residues and the pH and temperature optima were found to be 7.5 and 37 degrees C, respectively. mu-Calpain underwent a Ca(2+)-dependent autoproteolysis producing a fragment of 82KDa. The N-terminal sequence of mu-calpain showed 24 and 18% sequence identity with human and bovine mu-calpain.

Amino Acid Sequence↗
PubMed2002

Ostrich antithrombin III: kinetics and mechanism of inhibition of ostrich thrombin.

A kinetic investigation of ostrich thrombin specificity, its regulation and evolutionary development in comparison to those of other well-characterised species may contribute to the understanding of the structure-function relationships of thrombin. Antithrombin III (ATIII) was purified from ostrich plasma by heparin-Sepharose and Super Q-650S chromatography. It exhibited a M(r) of 59.2K and a pI in the range of 5.2-6.0. The ostrich N-terminal sequence was compared to those of other known species and showed the highest identity with rabbit ATIII (31%). Inhibition studies included the interaction of ostrich and human ATIII with bovine, human and ostrich thrombin. At a 2:1 molar ratio of ostrich ATIII to enzyme, 20 and 40% remaining activity was found for bovine and ostrich thrombin, respectively. Ostrich thrombin exhibited a pH and temperature optimum of 9.0 and 60 degrees C, respectively. Hydrolysis of seven peptide p-nitroanilide substrates by ostrich thrombin revealed D-Phe-Pip-Arg-pNA (k(cat)/K(m)=9.65 microM(-1)s(-1)) as the substrate with the highest catalytic efficiency. The effect of monovalent cations on ostrich thrombin catalysis revealed enhanced activity with Na(+). The calculated K(i) values for the complex formation between ostrich thrombin and ostrich (9.29 x 10(-11)M) and human (9.66 x 10(-11)M) ATIII are comparable to reported results. The results obtained from the present study confirmed that ostrich thrombin and ATIII are closely related to the corresponding molecules of other species in terms of physicochemical and kinetic properties.

Animals↗
PubMed1999

The isolation and partial characterization of precursor forms of ostrich carboxypeptidase.

Ostrich carboxypeptidases A and B were recently purified and characterized. The aim of this study was to isolate and purify, and partially characterize in terms of molecular weight, pI, amino acid composition and N-terminal sequencing, the precursor forms of carboxypeptidases from the ostrich pancreas. Inhibition studies with soybean trypsin inhibitor and activation studies with three proteases (bovine trypsin, bovine chymotrypsin and porcine elastase) were performed on crude ostrich acetone powder and the carboxypeptidase A and B activities were determined. SDS-PAGE was carried out after every incubation to monitor the rate and degree of conversion of a M(r) 66K component to procarboxypeptidase and carboxypeptidase A and B. The precursor forms were purified by Toyopearl Super Q and Pharmacia Mono Q chromatography. All three proteases converted the M(r) 66K component to procarboxypeptidases and carboxypeptidases over a set time interval, with carboxypeptidase A and B activities being detected in the acetone powder. Chymotrypsin was the preferred protease since it exhibited a more controlled activation of the procarboxypeptidases. The amino acid composition of procarboxypeptidase A revealed 525 residues. The N-terminal sequence of procarboxypeptidase A showed considerable homology when compared with several other mammalian sequences. M(r) and pI values of 52K and 5.23 were obtained for procarboxypeptidase A, respectively. This study indicated that ostrich procarboxypeptidase A is closely related to other mammalian procarboxypeptidase A molecules in terms of physicochemical properties.

Acetone↗
PubMed1998

Experimental infection of ostriches with Crimean-Congo haemorrhagic fever virus.

Following the occurrence of an outbreak of Crimean-Congo haemorrhagic fever (CCHF) among workers at an ostrich abattoir in South Africa in 1996, 9 susceptible young ostriches were infected subcutaneously with the virus in order to study the nature of the infection which they undergo. The ostriches developed viraemia which was demonstrable on days 1-4 following infection, with a maximum intensity of 4.0 log10 mouse intracerebral LD50/ml being recorded on day 2 in 1 of the birds. Virus was detectable in visceral organs such as spleen, liver and kidney up to day 5 post-inoculation, 1 day after it could no longer be found in blood. No infective virus was detected in samples of muscle, but viral nucleic acid was detected by reverse transcription-polymerase chain reaction in muscle from a bird sacrificed on day 3 following infection. It was concluded that the occurrence of infection in ostriches at abattoirs could be prevented by keeping the birds free of ticks for 14 days before slaughter.

Abattoirs↗
PubMed1999

The histidine-rich protamine from ostrich and tinamou sperm. A link between reptile and bird protamines.

We have characterized for the first time the proteins of two different species of palaeognathous birds, Struthio camelus australis (ostrich) and Nothoprocta perdicaria sanborni (Chilean tinamou). Similar to what had been previously reported in neognaths, the electrophoretic mobility, amino acid composition, and primary structure of the main protamine (P-II) component of these two species of birds are similar. However, in contrast to neognathous birds, the protamines from paleognaths display a higher electrophoretic mobility and a significantly different amino acid composition and protein sequence. The sperm and the main protamine component P-II from the ostrich reveal structural and compositional characteristics intermediate between neognathous birds and reptiles. The marked differences between the protamines and sperm structure of neognaths and paleognaths provide support to a phylogenetic relationship between neornithine birds in which these two groups represent two separate phylogenetic lines. Furthermore, these results shed some additional light on the controversial origin of birds. They provide further molecular support to the fossil record that suggests that reptiles and birds are closely related.

Alligators and Crocodiles↗
PubMed2001

Sweetness and enzymatic activity of lysozyme.

Hen egg lysozyme elicits a sweet taste sensation for human beings. Effects of reduction of disulfide bonds, heat treatment, and chemical modification of hen egg lysozyme on both sweetness and hydrolytic activity were investigated. Both the sweetness and enzymatic activities were lost when the intradisulfide linkage in a lysozyme molecule was reduced and S-3-(trimethylated amino) propylated. The sweetness and enzymatic activity of lysozyme were lost on heating at 95 degrees C for 18 h. These facts suggest that tertiary structures of lysozyme are indispensable for eliciting a sweet taste as well as enzymatic activity. Although the modification of carboxyl residues in a lysozyme by glycine methylester or aminomethansulfonic acid resulted in the loss of enzymatic activity by blocking the catalytic residues, the sweetness was fully retained. These results indicate that the sweetness of lysozyme was independent of its enzymatic activity. The lysozyme purified from goose egg white similarly elicited a sweet taste, although goose (g-type) lysozyme is quite different from hen egg lysozyme (c-type) on the basis of structural, immunological, and enzymatic properties. These findings indicate that a specific protein property of lysozyme is required for sweetness elicitation and that the enzymatic activity and carbohydrates produced by enzymatic reaction are not related to the sweet taste.

Animals↗
PubMedDate not supplied

Insight into residues critical for antithrombin function from analysis of an expanded database of sequences that includes frog, turtle, and ostrich antithrombins.

Complete sequences were determined for frog, turtle, and ostrich antithrombins. Protein sequence comparisons with the other 10 known antithrombin sequences and with sequences of other serpins have provided striking evidence for the conservation of the heparin activation mechanism and new insight into those residues important for heparin binding, for heparin activation, and for reactive center loop function, as well as an indication of which glycosylation sites might be needed for function. Importantly, an understanding of, as yet, poorly understood antithrombin-protein interactions will be greatly aided by this expanded database and comparative analysis.

Amino Acid Sequence↗
PubMed1999

Limb deformities of farmed ostrich (Struthio camelus) chicks in Botswana.

Limb deformities were detected in 135 out of 885 ostrich chicks, giving a prevalence of 15.3%. Tibiotarsal rotation affected 73% of the chicks with limb deformities, whereas rolled toes accounted for 36%. The right leg was more often affected than the left leg. The incidence of limb deformities was highest in 2- to 3-week-old ostrich chicks. The incidence of limb deformities was highest at the beginning of the breeding season and lowest towards the end, when it was relatively warmer. The mean serum manganese and zinc levels in deformed ostrich chicks were higher than the levels reported for normal chicks.

Age Factors↗