鸵鸟性别鉴定的分子标记方法

鸵鸟(Struthiocamelus)属于平胸总目鸟类,雌雄鸵鸟在性成熟前外部形态相同,很难通过外观和形态来鉴定性别,给早期分群饲养造成了很大的困难。实验利用鸵鸟羽毛提取基因组DNA,之后利用EE0.6和CHD基因中2个引物组合对3对已知性别和9只未知性别鸵鸟的性别基因片段进行特异性扩增。结果显示,这对引物组合在雄性鸵鸟的DNA中未扩增出片段,在雌性鸵鸟DNA中扩增出1条片段,可以对鸵鸟的性别作出准确鉴定,从而解决幼雏期鸵鸟难以从外貌上区分其性别的问题。     

Ostrich (Struthio camelus) carboxypeptidase A: Purification,kinetic properties and characterization of the pancreatic enzyme

• 1.1. Carboxypeptidase A and carboxypeptidase A,-type from the pancreas of the ostrich were purified by water extraction of acetone powder, aminobenzylsuccinic acid affinity and hydroxylapatite chromatography.
• 2.2. The final preparations were homogeneous when subjected to SDS-PAGE and PAGE. The M, values obtained from SDS-PAGE for CPAp and CPA,-type were 34,600 and 34,400, respectively.
• 3.3. The effects of inhibitors (1,10 phenanthroline and indole-3-acetic acid), pH and temperature on CPA activity were examined. K_i-values for CPI, PPA, D-phe, D-trp and aminobenzylsuccinic acid were determined.
• 4.4. K_m, k_cat and k_cat/K_m values were determined for hipp-phe, cbz-gly-phe, cbz-(gly)₂-phe, cbz-gly-leu, cbz-(gly)₂-leu and cbz-(gly)₂-val.
• 5.5. N-terminal sequencing and amino acid analysis were performed for CPA_β and CPA_τ-type.

     

The Tarsometatarsus of the Ostrich Struthio camelus: Anatomy,Bone Densities,and Structural Mechanics

Background

The ostrich Struthio camelus reaches the highest speeds of any extant biped, and has been an extraordinary subject for studies of soft-tissue anatomy and dynamics of locomotion. An elongate tarsometatarsus in adult ostriches contributes to their speed. The internal osteology of the tarsometatarsus, and its mechanical response to forces of running, are potentially revealing about ostrich foot function.

Methods/Principal Findings

Computed tomography (CT) reveals anatomy and bone densities in tarsometatarsi of an adult and a young juvenile ostrich. A finite element (FE) model for the adult was constructed with properties of compact and cancellous bone where these respective tissues predominate in the original specimen. The model was subjected to a quasi-static analysis under the midstance ground reaction and muscular forces of a fast run. Anatomy–Metatarsals are divided proximally and distally and unify around a single internal cavity in most adult tarsometatarsus shafts, but the juvenile retains an internal three-part division of metatarsals throughout the element. The juvenile has a sparsely ossified hypotarsus for insertion of the m. fibularis longus, as part of a proximally separate third metatarsal. Bone is denser in all regions of the adult tarsometatarsus, with cancellous bone concentrated at proximal and distal articulations, and highly dense compact bone throughout the shaft. Biomechanics–FE simulations show stress and strain are much greater at midshaft than at force applications, suggesting that shaft bending is the most important stressor of the tarsometatarsus. Contraction of digital flexors, inducing a posterior force at the TMT distal condyles, likely reduces buildup of tensile stresses in the bone by inducing compression at these locations, and counteracts bending loads. Safety factors are high for von Mises stress, consistent with faster running speeds known for ostriches.

Conclusions/Significance

High safety factors suggest that bone densities and anatomy of the ostrich tarsometatarsus confer strength for selectively critical activities, such as fleeing and kicking predators. Anatomical results and FE modeling of the ostrich tarsometatarsus are a useful baseline for testing the structure’s capabilities and constraints for locomotion, through ontogeny and the full step cycle. With this foundation, future analyses can incorporate behaviorally realistic strain rates and distal joint forces, experimental validation, and proximal elements of the ostrich hind limb.     

Histochemical Characterization and Distribution of Fiber Types in the Pectoralis Muscle of the Ostrich (Struthio camelus) and Emu (Dromaius novaehollandiae)

The muscle fibers of the pectoralis (M. pectoralis pars thoracicus) of a male and a female ostrich (Struthio camelus) and a male and a female emu (Dromaius novaehollandiae) were studied histochemically for succinate dehydrogenase and myofibrillar adenosine triphosphatase. Slow-tonic (ST), fast-twitch oxidative-glycolytic (FOG) and fast-twitch glycolytic (FG) fibers were approximately equal in number and distribution in the emu pectoralis examined. In the ostriches, both predominantly FG and approximately equal areas, were present. ST fibers were significantly (P ≤ 0.05) larger than the similarly (P ≥ 0.05) sized FG and FOG fibers in the female ostrich and emus. In the male ostrich ST fibers were smaller (P ≤ 0.05) than FG fibers, neither of which were significantly (P ≥ 0.05) different from FOG fibers. The ratites have the greatest percentage and widest distribution of ST fibers found in any avian pectoralis studied to date. This could represent the ancestoral avian pectoralis, neoteny or an effect of flightlessness. ST fibers are used in the maintenance of posture, which is probably the main role of the pectoralis in the emu. The predominantly FG areas of the ostrich are indicative of an additional function, namely, behavioural display. Sexual dimorphism in the ostrich pectoralis is strongly suggested.     

Egyptian Vultures Neophron percnopterus and Ostrich Struthio camelus eggs: the origins of stone-throwing behaviour

Experiments were carried out on wild and hand-reared Egyptian Vultures to investigate the origins of the stone-throwing this species uses to break into Ostrich eggs. There was no evidence of cultural transmission for stone-throwing through copying experienced birds. A naïve captive-reared bird threw stones once an Ostrich egg had been linked with a food reward. The origins of aimed stone-throwing are probably related to the unaimed throwing of small eggs, since the actions are similar, and all tested birds strongly preferred to throw rounded or egg-like stones, rather than jagged ones, at Ostrich eggs.     

Mechanics of running of the ostrich (Struthio camelus)

Ostriches have been filmed running fast in their natural habitat. A female ostrich has been dissected and the principal bones, muscles and tendons in a leg have been measured. It is calculated that stresses up to 240 kN m⁻² and 40 MN m⁻², respectively, act in the digital flexor muscles and their tendons during running. Tensile and compressive stresses up to about 70MNm⁻² and 110 MNm⁻² act in the tibiotarsus. A large proportion of the energy which would otherwise be required for running is probably saved by elastic storage in tendons. Comparisons are made with the legs of flying birds and of antelopes.     

Ostrich (Struthio camelus) eggshell matrix contains two different C-type lectin-like proteins. Isolation, amino acid sequence, and posttranslational modifications

Comparative analysis of the human and mouse genomic sequences downstream of the apolipoprotein E gene (APOE) revealed a highly conserved element with previously undefined function. In reporter gene transfection studies, this element which is located approximately 42 kb distal to APOE was found to have silencer activity in a subset of cell lines examined. Analysis of transgenic mice containing a fusion construct linking this distal 631 bp conserved element to a reporter gene comprised of the human APOE gene with its proximal promoter resulted in robust brain expression of the transgenic human apoE mRNA in three independent transgenic lines, supporting the identification of a novel brain controlling region (BCR). Further studies using immunohistochemistry revealed widespread human apoE localization throughout the brains of the BCR-apoE transgenic mice with prominent expression in the cortex and diencephalon. In addition, double-label immunofluorescence performed on brain sections and cultures of primary cortical cells localized human apoE protein to cortical neurons and microglia. These studies demonstrate that comparative sequence analysis is a successful strategy to predict candidate regulatory regions in vivo, although they do not imply that this element controls apoE expression physiologically.     

Breeding biology of ostriches (Struthio camelus) in the Serengeti ecosystem, Tanzania

Ostrich breeding behaviour in the Serengeti ecosystem, Tanzania was investigated for differences in laying dates between low altitude western area (WA) and high altitude eastern area (EA) populations. Ostriches in WA laid eggs significantly earlier than in EA. The differences could be attributed to topography and rainfall pattern. Reliable rains in lower altitudes ensure availability of food that in turn influences the whole process of the reproductive cycle. Clutches were contributed by several females with a nest having up to 38 eggs. We also compared the frequency of observation of predators, ostriches, nests, 'singletons' (single eggs laid randomly) and broods between the two areas. There was no significant difference between WA and EA in 1) ostrich/nest ratio, indicating similar breeding densities; 2) ostrich/predator and predator/nest ratios, indicating that predation pressure was equally high; 3) nest/singleton and predator/singleton ratios, indicating that loss of nests did not vary between areas. However, there were significantly more predators, nests and ostriches compared to broods in EA than in WA, indicating a significantly lower reproductive success in EA. Using metapopulation terminology, ostriches in EA could be regarded as a 'sink' population and those in WA as a 'source' population, but investigations over longer time-periods are needed to further resolve if this is the case.     

Differentiation of the acrosomal complex in ostrich (Struthio camelus) spermatids

The acrosomal complex of ostrich sperm consists of a small, cone-shaped acrosome and a slender, cylindrical perforatorium housed within a deep endonuclear canal. The perforatorium is almost exclusively endonuclear in location and is only covered by the acrosome at its point of origin in the apical subacrosomal space. The development of the acrosome is generally similar to that described in other non-passerine birds. Small proacrosomal granules (vesicles) emanating from the Golgi apparatus coalesce to form a large, membrane-bound acrosomal vesicle filled with homogeneous, electron-dense material. The acrosomal vesicle attaches to the nucleus via a shallow depression and subsequently collapses to form the typical cap-like acrosome of non-passerine birds. In ostrich spermatids the endonuclear canal becomes obvious when the collapsed acrosomal vesicle has assumed a dumbbell-shaped appearance. The perforatorium, which originates from moderately electron-dense material contained within the apical subacrosomal space, expands within the deepening endonuclear canal. The material of the perforatorium does not originate in the form of an obvious granule as in chicken and budgerigar spermatids. Indications are that in ostrich spermatids the developing acrosome plays a role in the shaping of the tip of the nucleus. The perforatorium, however, appears to represent a residual structure that has no specifically identified function. © 1996 Wiley-Liss, Inc.     

Tibiofibular junction of the South African ostrich (Struthio camelus australis)

The tibiofibular junction of the South African ostrich (Struthio camelus australis) consists of the Ligg. tibiofibularia caudale, craniale proximale and distale, obliquum, and interosseum. The motion range of the fibula, respective to the tibiotarsus, averaged 35°. This junction is, however, not freely mobile as there is a resting position from which the fibula can be pronated an average of 14° (counterclockwise motion of the right fibula from the proximal view) and supinated an average of 21°. Flexion and inward rotation of the tibiotarsus causes fibular supination. This behavior is induced by the lateral meniscus (which follows the movements of the femur on the plateau of the tibiotarsus) and the femorofibular joint surfaces. As the fibular attachment of the popliteus muscle cannot migrate medially, due to its relative fixation by the femorofibular joint surfaces, fibula supination (tibiotarsus pronation), caused by contraction of the popliteus muscle leads to an inward rotation of the tibiotarsus relative to the femur. The ligaments impede excessive pro- and supination. Except for the Lig. tibiofibulare craniale distale, all ligaments also comprise fibers taut in intermediate positions—the Ligg. obliquum and interosseum each have a fiber bundle that is taut in all positions. Tibiotarsus and fibula have no joint surfaces for a common articulation. Hence, the proximal junction should not be termed “articulation” (especially with regard to the distal “syndesmosis”). © 1996 Wiley-Liss, Inc.     

Hematologic and blood chemistry values of the Masai ostrich (Struthio camelus)

Normal mean values for hematocrit, hemoglobin concentration, erythrocyte and leukocyte counts, hematimetric indices, erythrocyte dimensions, glucose, urea, uric acid, cholesterol, creatinine, total bilirubin, serum aspartate aminotransferase, serum alanine aminotransferase, alkaline phosphatase, creatinine phosphokinase, lactic dehydrogenase, inorganic phosphorus, chloride, total plasma protein, sodium, potassium, calcium, and magnesium were obtained from the blood or plasma of four Masai ostriches (Struthio camelus) when juveniles at 5 mo of age and as adults 1 yr later in the Barcelona Zoo (Spain). Young ostriches had significantly lower concentrations of hematocrit, hemoglobin concentration, calcium, and magnesium, and higher levels of total protein and potassium, than the adult individuals. The rest of the parameters were not significantly different between the two age groups. The data obtained provide reference values for Masai ostriches.     

A preliminary microsatellite genetic map of the ostrich (Struthio camelus)

Molecular genetic maps can provide information for the identification and localization of major genes associated with quantitative traits. However, there are currently no published genetic linkage maps for any ratites. Herein, a preliminary genetic map of ostrich was developed using a two-generation ostrich reference family by linkage analysis of 104 polymorphic microsatellite markers, including 40 novel markers reported in this study. A total of 35 microsatellite markers were placed into 13 linkage groups. Five linkage groups are composed of three or more loci, whereas the remaining eight groups each contained two markers. The sex-averaged map spans 365.4 cM. The marker interval of each linkage group ranges from 5.3 to 25.4 cM, and the average interval distance is 16.61 cM. The male map covers 342.7 cM, with an average intermarker distance of 15.58 cM, whereas the female map is 456.7 cM, with the average intermarker spacing of 20.76 cM. In order to screen the orthologous loci between ostrich and chicken, all of the flanking sequences of the 104 polymorphic loci, nine monomorphic loci and a further 12 reported microsatellite loci for ostrich were screened against the chicken genomic sequence using the BLAST algorithm (Altschul et al., 1990), and corresponding orthologs were found for 13 sequences. The microsatellite loci and genetic map developed in this study will be useful for QTL mapping, population genetics and phylogenetic studies in the ratite. In addition, the 13 orthologous loci identified in this study will be advantageous to the construction of a comparative genetic map between chicken and ostrich.     

Laying, egg and hatchability characteristics in ostrich (Struthio camelus) at different age

The experimental material comprised 7 ostrich families (7 males and 14 females) of which five families were at the age of 7 and two at the age of 5 years. In the course of the entire reproductive season, the following parameters were analysed: length of the laying period, mean laying rate, number of eggs laid by one female, proportion ofhatching eggs, egg weight and shape, egg weight lost during incubation, egg fertilisation, percentage of dead embryos and unhatched chicks, hatchability from fertilised and set eggs. Seven year-old ostriches were characterised by shorter laying period (134 days) but, at the same time, by higher proportions of hatching eggs. This group was also characterised by high egg fertilisation (79.7%) as well as high hatchability indices at simultaneous highest embryo mortality during incubation (11.6 %). Five year-old ostriches exhibited a longer laying period (175 days) during which females laid more eggs (49 pcs.). In addition, this group was characterised by a smaller proportion of hatching eggs, better egg fertilisation indices (83.5%) and hatchability results. Moreover, the determined higher egg shape index indicates that the 5 year-old females laid eggs which were more spherical. Recapitulating, the obtained results indicate that, under Polish conditions, better indices of laying performance, egg fertilisation and hatchability were observed in the group of 5 year-old ostriches.     

Prevalence of antibodies to Toxoplasma gondii in ostriches (Struthio camelus)

Serum samples from 973 ostriches (Struthio camelus) in Canada were examined for antibodies to Toxoplasma gondii by the modified agglutination test incorporating mercaptoethanol and formalin-fixed whole tachyzoites. Twenty-eight (2.9%) of the 973 birds were found to be seropositive for antibodies to T. gondii at titers of 1:25 in 15 birds, 1:50 in 12 birds, and 1:500 in 1 bird. This is the first record of T. gondii exposure in ostriches, and it supports the hypothesis that all avian species are susceptible to Toxoplasma infection. Nevertheless, the results of this study suggest that the risk of acquiring toxoplasmosis from ostriches as a food source is low.     

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.     

The isolation and characterization of serum albumin from the ostrich (Struthio camelus)

Ostrich serum albumin (OsSA) was purified by a combination of heat fractionation and polyethylene glycol precipitation. Equilibrium centrifugation revealed a relative molecular mass of 71,666 for the purified monomer, whereas the presence of a dimeric form was confirmed by means of PAGE and SDS-PAGE analysis. Compared to other species, relatively high levels of proline, glycine, isoleucine and histidine together with lowered amounts of half cystine, phenylalanine and arginine were observed in OsSA. A single N-terminal aspartic acid was identified. Isolated chicken adipocytes revealed a significantly lower in vitro lipolytic responsiveness towards added glucagon when OsSA replaced bovine serum albumin (BSA) in the medium (Km = 6.359 and 1.135 nM, Vm = 36.70 and 46.72 nmol/hr/micrograms adipocyte DNA for OsSA and BSA respectively).     

A search for genetic markers associated with egg production in the ostrich (Struthio camelus)

The aim of the current study was to search for genetic markers, microsatellite loci associated with laying performance in ostriches. The material consisted of two groups of ostrich hens characterized by high or low laying performance (over 75 and less than 25 eggs per season, respectively). The investigation covered 30 microsatellite loci characteristic for the ostrich (the CAU group) and led to identification of significant differences in allele and genotype frequencies between the two groups of hens considered. Out of a total of 30 microsatellite loci examined, 28 showed different alleles in relation to analyzed performance groups. In hens of high laying performance (HP group, n = 12), specific alleles occurred in 23 microsatellite loci (40 alleles of 243 identified), while in those of low egg production (LP group, n = 12), they occurred in 22 (51 alleles of 243 identified). The results indicate the usefulness of the microsatellite loci as the potential genetic markers associated with laying performance that can be applied for genetic improvement of ostrich flocks.