Engineering the cellulolytic bacterium, Clostridium thermocellum, to co-utilize hemicellulose.

Consolidated bioprocessing (CBP) of lignocellulosic biomass holds promise to realize economic production of second-generation biofuels/chemicals, and Clostridium thermocellum is a leading candidate for CBP due to it being one of the fastest degraders of crystalline cellulose and lignocellulosic biomass. However, CBP by C. thermocellum is approached with co-cultures, because C. thermocellum does not utilize hemicellulose. When compared with a single-species fermentation, the co-culture system introduces unnecessary process complexity that may compromise process robustness. In this study, we engineered C. thermocellum to co-utilize hemicellulose without the need for co-culture. By evolving our previously engineered xylose-utilizing strain in xylose, an evolved clonal isolate (KJC19-9) was obtained and showed improved specific growth rate on xylose by ∼3-fold and displayed comparable growth to a minimally engineered strain grown on the bacteria's naturally preferred substrate, cellobiose. To enable full xylan deconstruction to xylose, we recombinantly expressed three different ß-xylosidase enzymes originating from Thermoanaerobacterium saccharolyticum into KJC19-9 and demonstrated growth on xylan with one of the enzymes. This recombinant strain was capable of co-utilizing cellulose and xylan simultaneously, and we integrated the ß-xylosidase gene into the KJC19-9 genome, creating the KJCBXint strain. The strain, KJC19-9, consumed monomeric xylose but accumulated xylobiose when grown on pretreated corn stover, whereas the final KJCBXint strain showed significantly greater deconstruction of xylan and xylobiose. This is the first reported C. thermocellum strain capable of degrading and assimilating hemicellulose polysaccharide while retaining its cellulolytic capabilities, unlocking significant potential for CBP in advancing the bioeconomy.

Immunity on ice: The impact of methamphetamine on peripheral immunity.

Methamphetamine (METH) regulation of the dopamine transporter (DAT) and central nervous system (CNS) dopamine transmission have been extensively studied. However, our understanding of how METH influences neuroimmune communication and innate and adaptive immunity is still developing. Recent studies have shed light on the bidirectional communication between the CNS and the peripheral immune system. They have established a link between CNS dopamine levels, dopamine neuronal activity, and peripheral immunity. Akin to dopamine neurons in the CNS, a majority of peripheral immune cells also express DAT, implying that in addition to their effect in the CNS, DAT ligands such as methamphetamine may have a role in modulating peripheral immunity. For example, by directly influencing DAT-expressing peripheral immune cells and thus peripheral immunity, METH can trigger a feed-forward cascade that impacts the bidirectional communication between the CNS and peripheral immune system. In this review, we aim to discuss the current understanding of how METH modulates both innate and adaptive immunity and identify areas where knowledge gaps exist. These gaps will then be considered in guiding future research directions.

Characterization of elbow flexion torque after nerve reconstruction of patients with traumatic brachial plexus injury.

BACKGROUND: The modified British Medical Research Council muscle grading system remains the primary method for assessing outcomes following surgical intervention despite its subjectivity and numerous inherent flaws. A new objective outcome measure of elbow function in patients with a brachial plexus injury is proposed. METHODS: 11 patients with a reconstructed brachial plexus (nerve reconstruction) and 10 unimpaired control subjects were evaluated. A custom apparatus measuring elbow flexion torque was developed. The subjects were asked to match their elbow flexion torque to a predefined torque. Time taken to achieve this predefined elbow flexion torque (latency) and duration of steady torque output were used as outcome measures. RESULTS: Healthy individuals were better at maintaining and regulating elbow torque. The patients with a brachial plexus injury showed similar latency while increasing their elbow torque (normalized to maximum elbow torque) but lacked the ability to modulate the latency with demand as the healthy subjects. INTERPRETATION: This novel measure provides objective information regarding the patient's ability to control elbow torque after nerve reconstruction.

Muscle activation for targeted elbow force production following surgical reconstruction in adults with brachial plexus injury.

Nerve transfer or grafting surgery to restore elbow flexion in peripheral nerve injuries has been an effective technique, but alters neuromuscular control compared with healthy individuals. This study compared neuromuscular control in the elbow flexors of 11 unimpaired control subjects and 11 adult patients with traumatic brachial plexus injury who underwent a nerve transfer or grafting procedure to the biceps motor branch to restore elbow flexion. The subjects performed a series of trials to generate a specific percentage of their maximum elbow torque. Each trial had an increasing and decreasing stairstep torque pattern that the subjects were asked to match. The amount of time that the subject's elbow torque was maintained within 5% of the target torque was calculated. The hypothesis was that there was a significant difference in the neuromuscular control between the two groups during elbow isometric torque generation. A secondary hypothesis was that a relationship existed between the neuromuscular control and the torque level for each group. The results demonstrated that neuromuscular control was different between the groups and there were significant differences in how torque levels are generated. The control group more easily modulated their myoelectric activation and achieved greater neuromuscular control variability with varying torque demand. The nerve transfer or grafting group could not modulate their myoelectric activation with changing torque demands. Further studies focusing on the improvement of neuromuscular control are needed to optimize functional outcomes in nerve injury patients.

Fall Prevention Training for Service Members With an Amputation or Limb Salvage Following Lower Extremity Trauma.

INTRODUCTION: Recent military conflicts have resulted in a significant number of lower extremity injuries to U.S. service members that result in amputation or limb preservation (LP) procedures. Service members receiving these procedures report a high prevalence and deleterious consequences of falls. Very little research exists to improve balance and reduce falls, especially among young active populations such as service members with LP or limb loss. To address this research gap, we evaluated the success of a fall prevention training program for service members with lower extremity trauma by (1) measuring fall rates, (2) quantifying improvements in trunk control, and (3) determining skill retention at 3 and 6 months after training. MATERIALS AND METHODS: Forty-five participants (40 males, mean [±SD] age, 34 ± 8 years) with lower extremity trauma (20 with unilateral transtibial amputation, 6 with unilateral transfemoral amputation, 5 with bilateral transtibial amputation, and 14 with unilateral LP procedures) were enrolled. A microprocessor-controlled treadmill was used to produce task-specific postural perturbations which simulated a trip. The training was conducted over a 2-week period and consisted of six 30-minute sessions. The task difficulty was increased as the participant's ability progressed. The effectiveness of the training program was assessed by collecting data before training (baseline; repeated twice), immediately after training (0 month), and at 3 and 6 months post-training. Training effectiveness was quantified by participant-reported falls in the free-living environment before and after training. Perturbation-induced recovery step trunk flexion angle and velocity was also collected. RESULTS: Participants reported reduced falls and improved balance confidence in the free-living environment following the training. Repeated testing before training revealed that there were no pre-training differences in trunk control. The training program improved trunk control following training, and these skills were retained at 3 and 6 months after training. CONCLUSION: This study showed that task-specific fall prevention training reduced falls across a cohort of service members with diverse types of amputations and LP procedures following lower extremity trauma. Importantly, the clinical outcome of this effort (i.e., reduced falls and improved balance confidence) can lead to increased participation in occupational, recreational, and social activities and thus improved quality of life.

A Comprehensive Review on the Supraclavicular Flap for Head and Neck Reconstruction.

ABSTRACT: The supraclavicular artery flap (SCF) is a highly vascularized fasciocutaneous flap overlying the shoulder. The flap was first described in 1979 by Lamberty but did not gain popularity until much later due to lack of a reliable technique. The main advantages of using the SCF include avoiding microsurgical techniques, requiring only a single-stage operation, shorter operative time compared with alternative options, and a wider patient population including those with comorbidities who may be excluded from more extensive operations including free flaps surgeries. The SCF has been successfully performed on individuals with advanced age, poor nutrition, cachexia, obesity, diabetes, tobacco use, severe chronic obstructive pulmonary disease, hypertension, coronary artery disease, peripheral vascular disease, supraventricular tachycardia, atrial fibrillation, heart failure, asthma, and steroid use. The largest disadvantages of the SCF include the possibility of distal tip necrosis, size limitation without pre-expansion, and a moderately visible donor site scar. The following review and meta-analysis of the SCF details its use historically as both an island and a pedicle flap, and its application in head and neck reconstruction.

IMU filter settings for high intensity activities.

BACKGROUND: Recommendations for cut-off frequencies for inertial measurement units (IMU) are either based on marker-based motion analysis or based on low intensity activities. The selection of filter cut-off frequencies can impact the extracted variables from the filtered signal. There are no recommendations for IMU filter settings when collecting biomechanical data of high intensity activities. RESEARCH QUESTION: What are appropriate IMU cut-off frequency filter settings for high intensity activities? METHODS: Ten unimpaired participants were studied during controlled postural perturbations using a microprocessor-controlled treadmill. Disturbances were delivered in forward and backward directions and incrementally increased in both directions until the participant was unable to maintain an upright posture and the trial resulted in a fall. An IMU was placed on their sternum to obtain trunk sagittal kinematics. Custom code was implemented to estimate trunk angle, angular velocity, and linear acceleration about the flexion-extension axis in the trunk IMU coordinate system. The three trials that resulted in falls in each direction for each participant (60 total trials) were analysed. These trials were limited to 500 msec of the disturbance period. The cut-off frequency was calculated for trunk kinematics using 99 percent of the energy spectrum (E99). RESULTS: The trunk flexion angle (4 ± 4 Hz) and linear acceleration (35 ± 10 Hz) cut-off frequencies agreed with previously reported values. The cut-off frequency for trunk flexion angular velocity (26 ± 7 Hz) was higher than values previously reported. SIGNIFICANCE: Selection of cut-off frequency should be based on segment accelerations and not simply activity or segment of interest. Deliberate selection and reporting of filter settings in biomechanics research will improve data quality, reliability of inferences, and reproducibility of studies.

Immune checkpoint blockade reprograms systemic immune landscape and tumor microenvironment in obesity-associated breast cancer.

Immune checkpoint blockade (ICB) has improved outcomes in some cancers. A major limitation of ICB is that most patients fail to respond, which is partly attributable to immunosuppression. Obesity appears to improve immune checkpoint therapies in some cancers, but impacts on breast cancer (BC) remain unknown. In lean and obese mice, tumor progression and immune reprogramming were quantified in BC tumors treated with anti-programmed death-1 (PD-1) or control. Obesity augments tumor incidence and progression. Anti-PD-1 induces regression in lean mice and potently abrogates progression in obese mice. BC primes systemic immunity to be highly responsive to obesity, leading to greater immunosuppression, which may explain greater anti-PD-1 efficacy. Anti-PD-1 significantly reinvigorates antitumor immunity despite persistent obesity. Laminin subunit beta-2 (Lamb2), downregulated by anti-PD-1, significantly predicts patient survival. Lastly, a microbial signature associated with anti-PD-1 efficacy is identified. Thus, anti-PD-1 is highly efficacious in obese mice by reinvigorating durable antitumor immunity. VIDEO ABSTRACT.

The Current Status of the Autologous Fat Grafting for Pediatric Craniofacial Patients.

Since its first introduction, autologous fat grafting (AFG) has undergone multiple refinements and has become a common treatment option within plastic surgery. It is a safe, quick, economical, and minimally invasive method for volume augmentation and is finding its own indications in the pediatric craniofacial surgery patients. Because there is currently a paucity of literature regarding the use of AFG in the pediatric population compared with the adults, the authors performed a systematic review of the literature using PubMed, Cochrane Library databases, and the Journal of Plastic and Reconstructive Surgery using the terms of fat grafting/lipofilling, fat grafting, and craniofacial surgery to include articles that contained pediatric patients. While reviewing AFG in the pediatric craniofacial patients, indications, technique, and challenges were specifically evaluated and an algorithm of approach was proposed. In current practice, the choice of microvascular free flap versus AFG is one of the surgeon preferences on a case-by-case basis. With the low complication rate and ease of use, selection of AFG for the repair of soft tissue defects in pediatric craniofacial patients is increasing and may come to surpass use of traditional invasive methods such as free flaps. It should also be considered as a useful adjunct to other concurrent invasive procedures, that is, bony adjustments.

Cross-sectional validation of inertial measurement units for estimating trunk flexion kinematics during treadmill disturbances.

Postural perturbation training has been shown to reduce falls. The key outcome measures are trunk flexion kinematics, at recovery step. Motion capture is typically used, but requires space and trained staff. Small, inexpensive, portable inertial measurement units (IMU) are preferred for routine clinical care. IMUs have been validated for trunk motion during walking and running on a treadmill, however treadmill fall prevention training generates higher accelerations. The purpose of this study was to validate the IMU estimate of trunk kinematics against motion capture during treadmill disturbances. Ten healthy young adults had an IMU with a retro-reflective marker triad placed on their sternum to estimate trunk kinematics. Disturbances, increasing in magnitude, were delivered until the harness supported at least 50% of the subject's weight. Equivalence testing (α = 0.05) demonstrated the trunk angle (TA) and angular velocity (TAV) measured by the IMU and motion capture were equivalent. The 95% Confidence Intervals (TA: [-1, 1], TAV: [0, 17]) were within the equivalence interval (TA: [-2, 2], TAV: [-20, 20]) and the p-Values (TA: 0.005, TAV: 0.011) were less than alpha. This data confirms that IMUs provide a valid method for measuring trunk kinematics during treadmill perturbation training.

Comparison of overhead harness configurations for measuring trunk kinematics during treadmill disturbances.

BACKGROUND: Research has shown that postural perturbation training reduces falls. Trunk kinematics, at recovery step, are key outcome measures. Fall prevention training programs are being developed for routine clinical care. In these programs, the subject is positioned on a treadmill and subjected to forward and backward disturbances which simulate trips and slips. The patient wears a safety vest attached to an overhead harness to create a secure environment. Motion capture is used to measure trunk kinematics. RESEARCH QUESTION: It is important to verify that trunk kinematics are independent of harness configuration. The purpose of this study was to compare the trunk flexion angle and angular velocity at recovery step after forward and backward disturbances on a treadmill measured by motion capture with the harness in both a fixed and free position. METHODS: Ten healthy young adults (5/10 female, age: 29.2 ± 6.3 years, BMI: 24.2 ± 2.4) participated in this study. The subjects had retro-reflective markers placed on key anatomical landmarks to measure trunk kinematics. The participants experienced forward and backward disturbances, which incrementally increased in intensity until the harness clearly supported the subjects for three disturbances in both directions. The order of harness configurations was randomized across subjects and each subject participated in two consecutive rounds of disturbances, one round for each harness configuration. Equivalence testing was performed to demonstrate that the harness configurations were equivalent (α = 0.05). RESULTS AND SIGNIFICANCE: The Equivalence Test demonstrated that the trunk angle (TA) and angular velocity (TAV) were equivalent for the different harness configurations. The 95% Confidence Intervals (TA: [-2, 1], TAV: [-18, 16]) were within the equivalence interval (TA: [-3, 3], TAV: [-20, 20]) and the p-Values (TA: 0.008, TAV: 0.034) were less than alpha. Trunk kinematics are independent of overheard harness configurations during treadmill induced disturbances for clinical postural perturbation training.

Patient-Reported and Objectively Measured Function Before and After Reverse Shoulder Arthroplasty.

BACKGROUND AND PURPOSE: Documenting functional outcomes after reverse shoulder arthroplasty (RSA) is critical to advancing patient care. The interplay been self-reported and objectively measured outcome measures has not been widely described. The utilization of wearable devices to document upper extremity limb activity is a new approach for objectively measuring outcomes. Therefore, the purpose of this study was to evaluate changes in pain, and self-reported function and objectively measured limb activity after RSA. We also assessed the influence of pain on self-reported function and objectively measured limb activity to determine the impact of pain on outcomes after RSA. MATERIALS: This study implemented a prospective, repeated-measures design. Fourteen patients undergoing RSA underwent testing before surgery, and 2 and 12 months after surgery. Patient-reported instruments included pain, Disabilities of Arm, Shoulder and hands (DASH), and physical component summary (PCS) of the 36-Item Short Form Health Survey. Objective limb activity (mean activity value, m/s/min epoch; inactive time, %; low activity, %; and high activity, %) was captured with triaxial accelerometers worn on the upper and lower arm. A repeated-measures ANOVA tested for differences across time. The Spearman rank-order correlation was calculated to evaluate the influence of pain on DASH, PCS scores, and mean limb activity. RESULTS: Patient-reported measures improved after surgery (pain, P < .01; DASH, P < .01; PCS, P = .01). No change in limb activity was found at 1 year compared with preoperative values for mean (forearm, P = 1.00; arm, P = .36), inactivity (forearm, P = .33; arm, P = .22), low (forearm, P = .77; arm, P = .11) or high (forearm, P = 1.00; arm, P = .20) activity. There was a relationship between pain and DASH scores 1 year after surgery (P = .04) but not before surgery (P = .16), or 2 months after surgery (P = .30). There was no relationship between pain and PCS scores at any time point (preoperative, P = .97; 2 months, P = .21; 1 year, P = .08) nor pain and limb activity (forearm: preoperative, P = .36; 2 months, P = .67; 1 year, P = .16; arm: preoperative, P = .97; 2 months, P = .59; 1 year, P = .51). CONCLUSIONS: RSA reduced pain and enhanced patient-perceived function. Objectively measured upper extremity limb activity is not different 1 year after surgery compared with preoperative levels. LEVEL OF EVIDENCE: III.

Verification of an improved hip joint center prediction method.

In motion analysis, the hip joint center (HJC) is used to define the proximal location of the thigh segment and is also the point about which hip moments are calculated. The HJC cannot be palpated; its location must be calculated. Functional methods have been proposed but are difficult to perform by some clinical populations. Therefore, regression methods are utilized, but yield large errors in estimating the HJC location. These prediction methods typically utilize the anterior and posterior superior iliac spines, where excessive adipose tissue makes correctly locating difficult. A new regression method (Hara) utilizes leg length and has been shown to improve HJC location in cadavers and less error than previous pelvic based regression methods, such as those proposed by Harrington et al. This study compared the accuracy of the HJC location calculated with both of the Harrington methods and the Hara method. The coronal knee angle was calculated for each method using a static motion analysis trial, and compared to the tibiofemoral angle measured on a gold standard digital full-leg coronal radiograph. This study demonstrated that the Hara method was more accurate than either of the Harrington methods. The mean error between the gold standard x-ray measurement and the motion analysis calculation for the Harrington (stepwise and LOOCV), the Harrington (linear regression), and Hara regression methods, respectively were 6.0°, 4.0°, and 1.8°. Accurately modeling the HJC is critical for data interpretation and patient care. This study confirmed that the Hara HJC regression method is valid in an in-vivo setting.

Expression of vascular endothelial growth factor A isoforms is dysregulated in women with endometriosis.

Angiogenesis is a critical step in the development of ectopic lesions during endometriosis. Although total vascular endothelial growth factor (VEGF) A is elevated in the peritoneal fluid of women with endometriosis, there are contradictory reports on how levels of total endometrial VEGFA are altered in this disease. Furthermore, limited research is available on different VEGFA isoforms in women with endometriosis. Thus, the aim of the present study was to analyse levels of various VEGFA isoforms in women with and without endometriosis at different stages of the menstrual cycle. Quantitative polymerase chain reaction analysis showed that total VEGFA was highest during menstruation in endometriosis compared with controls (P=0.0373). VEGF121 and VEGF189 were similarly highest during menstruation in endometriosis compared with controls (P=0.0165 and 0.0154 respectively). The present study is also the first to identify the natural expression of VEGF111 in human tissue, which is also highest during menstruation in endometriosis (P=0.0464). This discovery of the natural production of VEGF111 in human endometrium, as well as the upregulation of VEGFA isoforms during menstruation in endometriosis, may shed further light on the development and progression of the disease, and improve our understanding of the regulation of endometrial angiogenesis.

Extensive genetic differentiation detected within a model marsupial, the tammar wallaby (Notamacropus eugenii).

The tammar wallaby (Notamacropus eugenii) is one of the most intensively studied of all macropodids and was the first Australasian marsupial to have its genome sequenced. However, comparatively little is known about genetic diversity and differentiation amongst the morphologically distinct allopatric populations of tammar wallabies found in Western (WA) and South Australia (SA). Here we compare autosomal and Y-linked microsatellite genotypes, as well as sequence data (~600 bp) from the mitochondrial DNA (mtDNA) control region (CR) in tammar wallabies from across its distribution. Levels of diversity at autosomal microsatellite loci were typically high in the WA mainland and Kangaroo Island (SA) populations (A = 8.9-10.6; He = 0.77-0.78) but significantly reduced in other endemic island populations (A = 3.8-4.1; He = 0.41-0.48). Autosomal and Y-linked microsatellite loci revealed a pattern of significant differentiation amongst populations, especially between SA and WA. The Kangaroo Island and introduced New Zealand population showed limited differentiation. Multiple divergent mtDNA CR haplotypes were identified within both SA and WA populations. The CR haplotypes of tammar wallabies from SA and WA show reciprocal monophyly and are highly divergent (14.5%), with levels of sequence divergence more typical of different species. Within WA tammar wallabies, island populations each have unique clusters of highly related CR haplotypes and each is most closely related to different WA mainland haplotypes. Y-linked microsatellite haplotypes show a similar pattern of divergence although levels of diversity are lower. In light of these differences, we suggest that two subspecies of tammar wallaby be recognized; Notamacropus eugenii eugenii in SA and N. eugenii derbianus in WA. The extensive neutral genetic diversity and inter-population differentiation identified within tammar wallabies should further increase the species value and usefulness as a model organism.

The importance of pelvic nerve fibers in endometriosis.

Several lines of recent evidence suggest that pelvic innervation is altered in endometriosis-affected women, and there is a strong presumption that nerve fibers demonstrated in eutopic endometrium (of women with endometriosis) and in endometriotic lesions play roles in the generation of chronic pelvic pain. The recent observation of sensory C, sensory A-delta, sympathetic and parasympathetic nerve fibers in the functional layer of endometrium of most women affected by endometriosis, but not demonstrated in most women who do not have endometriosis, was a surprise. Nerve fiber densities were also greatly increased in myometrium of women with endometriosis and in endometriotic lesions compared with normal peritoneum. Chronic pelvic pain is complex, and endometriosis is only one condition which contributes to this pain. The relationship between the presence of certain nerve fibers and the potential for local pain generation requires much future research. This paper reviews current knowledge concerning nerve fibers in endometrium, myometrium and endometriotic lesions, and discusses avenues of research that may improve our knowledge and lead to enriched understanding and management of endometriotic pain symptoms.

Tibiofemoral alignment in posterior stabilized total knee arthroplasty: Static alignment does not predict dynamic tibial plateau loading.

For total knee arthroplasty (TKA), neutral mechanical alignment produces balanced static knee loading. Dynamically, knee loading is affected by more than limb static alignment. We compared static and dynamic knee loading following TKA. Fifteen TKA patients were evaluated pre-operatively and 2 months and 2 years post-operatively. Tibiofemoral angles and medial tibial plateau loading were calculated. Pre-operatively, static medial load was greater for varus than valgus knees. Post-operatively, no relationship existed between tibiofemoral angle and static medial plateau load. Pre-operatively and post-operatively, dynamic medial load was not dependent on tibiofemoral angle. While all patients achieved equal static plateau load distributions at 2 years, only 47% had dynamic medial load distributions of 50 ± 10%. Static tibiofemoral alignment alone does not predict dynamic tibial loading.

Novel approaches to objectively assess shoulder function.

BACKGROUND: The purpose of this study was to evaluate the effectiveness of existing technologies implemented in a novel manner to objectively capture upper extremity function. MATERIALS AND METHODS: Patients scheduled to undergo reverse shoulder arthroplasty were recruited for the study. Functional limb use was measured with triaxial accelerometers worn in the subjects' natural living environment. Functional reach area was captured by 3-dimensional motion analysis testing as subjects were asked to circumduct their limb, reaching as far as possible in a circular manner. Statistical testing (α ≤ .05) was performed by paired t tests to identify differences between limbs. RESULTS: There was no difference in functional limb activity between sides for the lower (P = .497) or upper arm (P = .918) for inactivity time. Mean activity was greater for the uninvolved limb compared with the involved limb (lower arm, P = .045; upper arm, P = .005). Low-intensity activity was greater for the involved arm compared with the uninvolved arm (lower arm, P = .007; upper arm, P = .015), whereas high-intensity activity was greater for the uninvolved arm (lower arm, P = .013; upper arm, P = .005). Radius of the functional reach area was greater for the uninvolved limb compared with the involved limb (P = .006). CONCLUSIONS: Novel methods of capturing function were effective in discerning differences in side-to-side abilities among patients scheduled to undergo reverse shoulder arthroplasty. These testing procedures may be used to capture function across a spectrum of shoulder diseases. These objective data are invaluable in assessing the impact of disease and recovery after intervention and obtaining reimbursement from third-party payers.

Dominance, body size and internal relatedness influence male reproductive success in eastern grey kangaroos (Macropus giganteus).

Knowledge of the determinants of reproductive success is essential for understanding the adaptive significance of particular traits. The present study examined whether particular behavioural, morphological, physiological or genetic traits were correlated with male dominance and reproductive success using three semi-free-ranging captive populations (n = 98) of the eastern grey kangaroo (Macropus giganteus). The morphological traits measured included bodyweight, head, forearm, tail, pes and leg length, forearm and bicep circumference, and testis size. Blood samples were collected to determine serum testosterone concentrations. All individuals were typed for 10 microsatellite loci and paternity determined for each pouch young. To determine the influence of relatedness and genetic diversity on male reproductive success, internal relatedness, standardised heterozygosity and mean d(2) were calculated. Dominant males sired a significantly higher proportion of offspring than smaller, lower-ranked males and had higher testosterone concentrations. Males that sired offspring were significantly heavier and had larger body size. Sires were significantly more heterozygous and genetically dissimilar to breeding females than non-sires. Despite the wealth of knowledge on the social organisation of kangaroos, this is the first study to assign parentage and male reproductive success using molecular evidence.