Tau PTM Profiles Identify Patient Heterogeneity and Stages of Alzheimer's Disease.

To elucidate the role of Tau isoforms and post-translational modification (PTM) stoichiometry in Alzheimer's disease (AD), we generated a high-resolution quantitative proteomics map of 95 PTMs on multiple isoforms of Tau isolated from postmortem human tissue from 49 AD and 42 control subjects. Although Tau PTM maps reveal heterogeneity across subjects, a subset of PTMs display high occupancy and frequency for AD, suggesting importance in disease. Unsupervised analyses indicate that PTMs occur in an ordered manner, leading to Tau aggregation. The processive addition and minimal set of PTMs associated with seeding activity was further defined by analysis of size-fractionated Tau. To summarize, features in the Tau protein critical for disease intervention at different stages of disease are identified, including enrichment of 0N and 4R isoforms, underrepresentation of the C terminus, an increase in negative charge in the proline-rich region (PRR), and a decrease in positive charge in the microtubule binding domain (MBD).

Ice-Binding Proteins and Their Function.

Ice-binding proteins (IBPs) are a diverse class of proteins that assist organism survival in the presence of ice in cold climates. They have different origins in many organisms, including bacteria, fungi, algae, diatoms, plants, insects, and fish. This review covers the gamut of IBP structures and functions and the common features they use to bind ice. We discuss mechanisms by which IBPs adsorb to ice and interfere with its growth, evidence for their irreversible association with ice, and methods for enhancing the activity of IBPs. The applications of IBPs in the food industry, in cryopreservation, and in other technologies are vast, and we chart out some possibilities.

A peptide-binding domain shared with an Antarctic bacterium facilitates Vibrio cholerae human cell binding and intestinal colonization.

Vibrio cholerae, the causative agent of the disease cholera, is responsible for multiple pandemics. V. cholerae binds to and colonizes the gastrointestinal tract within the human host, as well as various surfaces in the marine environment (e.g., zooplankton) during interepidemic periods. A large adhesin, the Flagellar Regulated Hemagglutinin A (FrhA), enhances binding to erythrocytes and epithelial cells and enhances intestinal colonization. We identified a peptide-binding domain (PBD) within FrhA that mediates hemagglutination, binding to epithelial cells, intestinal colonization, and facilitates biofilm formation. Intriguingly, this domain is also found in the ice-binding protein of the Antarctic bacterium Marinomonas primoryensis, where it mediates binding to diatoms. Peptide inhibitors of the M. primoryensis PBD inhibit V. cholerae binding to human cells as well as to diatoms and inhibit biofilm formation. Moreover, the M. primoryensis PBD inserted into FrhA allows V. cholerae to bind human cells and colonize the intestine and also enhances biofilm formation, demonstrating the interchangeability of the PBD from these bacteria. Importantly, peptide inhibitors of PBD reduce V. cholerae intestinal colonization in infant mice. These studies demonstrate how V. cholerae uses a PBD shared with a diatom-binding Antarctic bacterium to facilitate intestinal colonization in humans and biofilm formation in the environment.

Controlled Self-Assembly of Nanoscale Superstructures in Phase-Change Ge-Sb-Te Nanowires.

Controlled growth of semiconductor nanowires with atomic precision offers the potential to tune the material properties for integration into scalable functional devices. Despite significant progress in understanding the nanowire growth mechanism, definitive control over atomic positions of its constituents, structure, and morphology via self-assembly remains challenging. Here, we demonstrate an exquisite control over synthesis of cation-ordered nanoscale superstructures in Ge-Sb-Te nanowires with the ability to deterministically vary the nanowire growth direction, crystal facets, and periodicity of cation ordering by tuning the relative precursor flux during synthesis. Furthermore, the role of anisotropy on material properties in cation-ordered nanowire superstructures is illustrated by fabricating phase-change memory (PCM) devices, which show significantly different growth direction dependent amorphization current density. This level of control in synthesizing chemically ordered nanoscale superstructures holds potential to precisely modulate fundamental material properties such as the electronic and thermal transport, which may have implications for PCM, thermoelectrics, and other nanoelectronic devices.

Adhesin domains responsible for binding bacteria to surfaces they colonize project outwards from companion split domains.

Bacterial adhesins attach their hosts to surfaces that the bacteria will colonize. This surface adhesion occurs through specific ligand-binding domains located towards the distal end of the long adhesin molecules. However, recognizing which of the many adhesin domains are structural and which are ligand binding has been difficult up to now. Here we have used the protein structure modeling program AlphaFold2 to predict structures for these giant 0.2- to 1.5-megadalton proteins. Crystal structures previously solved for several adhesin regions are in good agreement with the models. Whereas most adhesin domains are linked in a linear fashion through their N- and C-terminal ends, ligand-binding domains can be recognized by budding out from a companion core domain so that their ligand-binding sites are projected away from the axis of the adhesin for maximal exposure to their targets. These companion domains are "split" in their continuity by projecting the ligand-binding domain outwards. The "split domains" are mostly ß-sandwich extender modules, but other domains like a ß-solenoid can serve the same function. Bioinformatic analyses of Gram-negative bacterial sequences revealed wide variety ligand-binding domains are used in their Repeats-in-Toxin adhesins. The ligands for many of these domains have yet to be identified but known ligands include various cell-surface glycans, proteins, and even ice. Recognizing the ligands to which the adhesins bind could lead to ways of blocking colonization by bacterial pathogens. Engineering different ligand-binding domains into an adhesin has the potential to change the surfaces to which bacteria bind.

Horizontal Gene Transfer in Vertebrates: A Fishy Tale.

The recent assembly of the herring genome suggests this fish acquired its antifreeze protein gene by horizontal transfer and then passed a copy on to the smelt. The direction of gene transfer is confirmed by some accompanying transposable elements and by the breakage of gene synteny.

CD57 defines a novel cancer stem cell that drive invasion of diffuse pediatric-type high grade gliomas.

BACKGROUND: Diffuse invasion remains a primary cause of treatment failure in pediatric high-grade glioma (pHGG). Identifying cellular driver(s) of pHGG invasion is needed for anti-invasion therapies. METHODS: Ten highly invasive patient-derived orthotopic xenograft (PDOX) models of pHGG were subjected to isolation of matching pairs of invasive (HGGINV) and tumor core (HGGTC) cells. RESULTS: pHGGINV cells were intrinsically more invasive than their matching pHGGTC cells. CSC profiling revealed co-positivity of CD133 and CD57 and identified CD57+CD133- cells as the most abundant CSCs in the invasive front. In addition to discovering a new order of self-renewal capacities, i.e., CD57+CD133- > CD57+CD133+ > CD57-CD133+ > CD57-CD133- cells, we showed that CSC hierarchy was impacted by their spatial locations, and the highest self-renewal capacities were found in CD57+CD133- cells in the HGGINV front (HGGINV/CD57+CD133- cells) mediated by NANOG and SHH over-expression. Direct implantation of CD57+ (CD57+/CD133- and CD57+/CD133+) cells into mouse brains reconstituted diffusely invasion, while depleting CD57+ cells (i.e., CD57-CD133+) abrogated pHGG invasion. CONCLUSION: We revealed significantly increased invasive capacities in HGGINV cells, confirmed CD57 as a novel glioma stem cell marker, identified CD57+CD133- and CD57+CD133+ cells as a new cellular driver of pHGG invasion and suggested a new dual-mode hierarchy of HGG stem cells.

A transgenic mouse model of Down syndrome acute lymphoblastic leukemia identifies targetable vulnerabilities.

Not available.

Isotope Dilution Space Ratio Declines Above the Age of 60 Years, Potentially Impacting Estimates of Total Energy Expenditure by the Doubly Labeled Water Method1-3, *, ˆ.

Doubly labeled water is gold standard for measuring total energy expenditure (TEE). Measurements using the method are sensitive to the isotope dilution space ratio (DSR). Accuracy and precision of the method might be improved if we could identify factors influencing DSR. We evaluated the potential associations of age, sex, ethnicity, anthropometry, body composition, turnover rates of the isotopes, and geographical elevation with DSR. We used univariate regression analysis to explore the relationships between the continuous variables and analysis of variance to test the relationships between the categorical variables with DSR. Subsequently, we used General Linear Modeling (GLM) and One-way ANOVA to evaluate the simultaneous associations of age, sex, ethnicity, fat-free mass (FFM) and fat mass (FM) on DSR. From 5,678 measurements complied from studies around the world with diverse ethnicity and living at various elevations, the average DSR was 1.0364 ± 0.0141 (mean ± SD). No meaningful physiological effect of any of the continuous and categorical variable on DSR was detected. GLM analysis revealed no effect of FFM and FM (P > 0.33) on DSR, but DSR decreased with age (P < 0.001) among those 60 years of age and older regardless of sex. Among the White who were younger than 60 years of age, DSR was not related to FFM and FM (P = 0.73) but was affected by both age and sex (P < 0.001). Previous estimates of age-related decline in TEE may have overestimated TEE at age 90. Validation studies on older participants are required to confirm this finding.

Protein inclusion into ice can dissociate subunits.

An antifreeze protein's inclusion into ice can be used to purify it from other proteins and solutes. Domains that are covalently attached to the antifreeze protein are also drawn into the ice such that the ice-binding portion of the fusion protein can be used as an affinity tag. Here we have explored the use of ice-affinity tags on multi-subunit proteins. When an ice-binding protein was attached as a tag to multisubunit complexes a substantial portion of each multimer dissociated during overgrowth by the ice. The protein subunit attached to the affinity tag was enriched in the ice and the other subunit was appreciably excluded. We suggest that step growth of the advancing ice front generates shearing forces on the bound complex that can disrupt non-covalent protein-protein interactions. This will effectively limit the use of ice-affinity tags to single subunit proteins.

Resonant domain-wall-enhanced tunable microwave ferroelectrics.

Ordering of ferroelectric polarization1 and its trajectory in response to an electric field2 are essential for the operation of non-volatile memories3, transducers4 and electro-optic devices5. However, for voltage control of capacitance and frequency agility in telecommunication devices, domain walls have long been thought to be a hindrance because they lead to high dielectric loss and hysteresis in the device response to an applied electric field6. To avoid these effects, tunable dielectrics are often operated under piezoelectric resonance conditions, relying on operation well above the ferroelectric Curie temperature7, where tunability is compromised. Therefore, there is an unavoidable trade-off between the requirements of high tunability and low loss in tunable dielectric devices, which leads to severe limitations on their figure of merit. Here we show that domain structure can in fact be exploited to obtain ultralow loss and exceptional frequency selectivity without piezoelectric resonance. We use intrinsically tunable materials with properties that are defined not only by their chemical composition, but also by the proximity and accessibility of thermodynamically predicted strain-induced, ferroelectric domain-wall variants8. The resulting gigahertz microwave tunability and dielectric loss are better than those of the best film devices by one to two orders of magnitude and comparable to those of bulk single crystals. The measured quality factors exceed the theoretically predicted zero-field intrinsic limit owing to domain-wall fluctuations, rather than field-induced piezoelectric oscillations, which are usually associated with resonance. Resonant frequency tuning across the entire L, S and C microwave bands (1-8 gigahertz) is achieved in an individual device-a range about 100 times larger than that of the best intrinsically tunable material. These results point to a rich phase space of possible nanometre-scale domain structures that can be used to surmount current limitations, and demonstrate a promising strategy for obtaining ultrahigh frequency agility and low-loss microwave devices.

Accelerated fragmentation of two thermoplastics (polylactic acid and polypropylene) into microplastics after UV radiation and seawater immersion.

To better understand the fate and assess the ingestible fraction of microplastics (by aquatic organisms), it is essential to quantify and characterize of their released from larger items under environmental realistic conditions. However, the current information on the fragmentation and size-based characteristics of released microplastics, for example from bio-based thermoplastics, is largely unknown. The goal of our work was to assess the fragmentation and release of microplastics, under ultraviolet (UV) radiation and in seawater, from polylactic acid (PLA) items, a bio-based polymer, and from polypropylene (PP) items, a petroleum-based polymer. To do so, we exposed pristine items of PLA and PP, immersed in filtered natural seawater, to accelerated UV radiation for 57 and 76 days, simulating 18 and 24 months of mean natural solar irradiance in Europe. Our results indicated that 76-day UV radiation induced the fragmentation of parent plastic items and the microplastics (50 - 5000 µm) formation from both PP and PLA items. The PP samples (48 ± 26 microplastics / cm2) released up to nine times more microplastics than PLA samples (5 ± 2 microplastics / cm2) after a 76-day UV exposure, implying that the PLA tested items had a lower fragmentation rate than PP. The particles' length of released microplastics was parameterized using a power law exponent (α), to assess their size distribution. The obtained α values were 3.04 ± 0.11 and 2.54 ± 0.06 (-) for 76-day UV weathered PP and PLA, respectively, meaning that PLA microplastics had a larger sized microplastics fraction than PP particles. With respect to their two-dimensional shape, PLA microplastics also had lower width-to-length ratio (0.51 ± 0.17) and greater fiber-shaped fractions (16%) than PP microplastics (0.57 ± 0.17% and 11%, respectively). Overall, the bio-based PLA items under study were more resistant to fragmentation and release of microplastics than the petroleum-based PP tested items, and the parameterized characteristics of released microplastics were polymer-dependent. Our work indicates that even though bio-based plastics may have a slower release of fragmented particles under UV radiation compared to conventional polymer types, they still have the potential to act as a source of microplastics in the marine environment, with particles being available to biota within ingestible size fractions, if not removed before major fragmentation processes.

Modern multiligament knee injury surgical reconstruction techniques can achieve excellent knee function and patient satisfaction, with low complication rates.

PURPOSE: To report on the recovery of strength and functional capacity symmetry following multiligament knee surgical reconstruction (MLKR), as well as the capacity of athletes to return to sport. METHODS: This prospective cohort study recruited 47 patients undergoing MLKR between February 2018 and July 2021. Forty patients had full outcome assessment postoperatively at 6, 12 and 24 months and were included in the analysis, 75% were knee dislocation one injuries and 60% were injured playing sport. Patient-reported outcome measures (PROMs) assessed included the International Knee Documentation Committee score, the Knee Outcome Survey, the Lysholm Knee Score and the Tegner Activity Scale (TAS). Patient satisfaction was also assessed. Objective assessment included assessment of active knee flexion and extension range of motion (ROM), the single (single horizontal hop for distance [SHD]) and triple (triple horizontal hop for distance [THD]) hop tests for distance and peak isokinetic knee flexor/extensor torque. RESULTS: All PROMs significantly improved (p < 0.001) from presurgery to 24 months postsurgery. At 24 months, 70% of patients were satisfied with their sports participation. Active knee flexion (p < 0.0001) and extension (p < 0.0001) ROM significantly improved over time, as did the limb symmetry indices (LSIs) for the SHD (p < 0.0001), THD (p < 0.0001), peak knee extensor (p < 0.0001) and flexor (p = 0.012) torque. While LSIs for the SHD, THD and knee flexor strength tended to plateau by 12 months, knee extensor strength continued to improve from 12 to 24 months. CONCLUSIONS: The majority of patients undergoing modern MLKR surgical techniques and rehabilitation can achieve excellent knee function, with low complication rates. LEVEL OF EVIDENCE: Level IV.

Patients undergoing multiligament knee reconstruction injured during pivoting sports demonstrate similar clinical, functional and return to sport outcomes by 2 years compared with those undergoing anterior cruciate ligament reconstruction.

PURPOSE: This study investigates the clinical and activity-based outcomes after anterior cruciate ligament reconstruction (ACLR) versus multiligamentous knee reconstruction (MLKR) following a pivoting sports injury. METHODS: Fifty MLKR patients were included, of which 20 (40%) were injured during pivoting sports. A further 50 patients undergoing ACLR following an injury during pivoting sports were consecutively recruited for comparison. Patients were assessed before the surgery and at 6-, 12- and 24 months with patient-reported outcome measures (PROMs) including the International Knee Documentation Committee (IKDC) form, Tegner activity scale (TAS) and anterior cruciate ligament return to sport after injury (ACL-RSI) score. Knee movement, the single (SHD) and triple (THD) hop tests for distance, and peak isokinetic knee extensor and flexor strength were assessed, with Limb Symmetry Indices (LSIs) calculated. Outcomes were compared across groups: (1) ACLR (n = 50), (2) MLKR (n = 50) and (3) MLKR due to pivoting sport injury (n = 20). RESULTS: IKDC, TAS and ACL-RSI scores remained lower (p < 0.05) in the full MLKR versus ACLR cohort at all timepoints. Comparing the ACLR and MLKR cohort that had injuries specifically during pivoting sports, the IKDC (p < 0.001) and TAS (p = 0.009) were higher in the ACLR group at 6 months, and the ACL-RSI was higher at 6 (p < 0.001) and 12 (p = 0.007) months, there were no further differences. Hop and knee extensor strength LSIs were lower (p < 0.05) in the full MLKR (versus ACLR) cohort at all timepoints (apart from the 24-month SHD LSI). However, the ACLR group only demonstrated greater LSIs than the pivoting sport MLKR for the SHD at 6 months (p < 0.001), and knee extensor strength at 6 (p < 0.001) and 12 (p < 0.001) months. CONCLUSIONS: While the recovery of patients undergoing MLKR due to a pivoting sports injury is delayed compared with their ACLR counterparts, the clinical outcome and activity profile are similar by 24 months. LEVEL OF EVIDENCE: Level IV.

Emigration of post-spawned twaite shad Alosa fallax, an anadromous and iteroparous fish, in a highly fragmented river.

Anthropogenic barriers are widely known to negatively impact the spawning migrations of anadromous fishes, by delaying or preventing passage upstream. Although the impacts of barriers on emigrating post-spawned adults are less well studied, they could potentially impact the fitness and subsequent return rates of iteroparous species. In this study, passive acoustic telemetry was used to track the emigrations of 53 twaite shad Alosa fallax in the River Severn basin in their first spawning migration a year after being tagged, giving insights into their emigration movements and the impacts of anthropogenic weirs on these movements. A. fallax began their emigrations after spending varying amounts of time and migrating various distances within the river, with late-emigrating individuals moving fastest and most directly. Emigrations became faster and more direct the further downstream individuals were from their furthest upstream extent. Downstream passage delays at weirs increased emigration times by a median of 61%, with environmental conditions (i.e., temperature, flow, and tidal influence on river level) having little influence on downstream passage at weirs with no modifications to facilitate fish passage. As weir-induced emigration delays are suggested to deplete energy reserves (when energy levels are already depleted post-spawning), limit spawning opportunities (by preventing access to downstream spawning habitat), and expose individuals to increased predation risk and suboptimal conditions (e.g., high temperatures), these delays can potentially diminish the benefits of iteroparity. The evidence presented here suggests that more consideration should be given to the potential impacts of anthropogenic barriers on the emigrations of iteroparous species when assessing river connectivity or undertaking barrier mitigation.

Combining acoustic telemetry with archival tagging to investigate the spatial dynamic of the understudied pollack, Pollachius pollachius.

Combining fish tracking methods is a promising way of leveraging the strengths of each approach while mitigating their individual weaknesses. Acoustic telemetry provides presence information as the fish move within receiver range, eliminating the need for tag recovery. Archival tags, on the other hand, record environmental variables on tag retrieval, enabling continuous path reconstruction of a fish beyond coastal regions. This study capitalizes on the combination of both methods for geolocating pollack, Pollachius pollachius, an understudied species of the northeast Atlantic, where declining stocks are raising concern. Essential knowledge of population structure and connectivity between essential habitats is critically lacking and could help inform stock assessment and management. The aims of the study were (1) to evaluate the feasibility of double-tagging pollack, known for being challenging to tag, and (2) to track seasonal movements across the Channel to gain first insights into pollack spatial ecology. In 2022, an extensive network of acoustic receivers was been deployed in the Channel along the French, English, and Belgian coasts as part of the Fish Intel project. We tagged 83 pollack with acoustic transmitters, among which 48 were double-tagged with data storage tags. Post-tagging survival assessment, conducted on a subset of 35 individuals, revealed a successful procedure with a 97% short-term survival rate. By October 2023, the acoustic telemetry network detected 30 out of 83 pollack at least once, with no large-scale movements observed across the Channel. Presence in the network fluctuates seasonally, peaking in summer, particularly among immature fish. Integrating acoustic detections with temperature and depth time series in a geolocation model enabled trajectory reconstruction of 10 recaptured pollack, seven of which were detected by the network. This combined tracking approach revealed coastal movements along the coast of Brittany in France, highlighting the ecological significance of the Iroise Sea for pollack throughout the year, particularly in summer. The geolocation model also suggested movements towards the entrance of the western Channel. This study highlights the complementarity of acoustic telemetry and archival tagging in reconstructing fish movements in their natural environment. As data accumulate, these innovative tracking methods promise to continually unveil new insights into the spatial ecology of the understudied pollack, which is essential for the species' management.

Legacy effects of historical gold mining on floodplains of an Australian river.

The gold rush at the end of the nineteenth century in south-eastern Australia resulted in the mobilization and re-deposition of vast quantities of tailings that modified the geomorphology of the associated river valleys. Previous studies of contamination risk in these systems have either been performed directly on mine wastes (e.g., battery sand) or at locations close to historical mine sites but have largely ignored the extensive area of riverine alluvial deposits extending downstream from gold mining locations. Here we studied the distribution of contaminant metal(loids) in the Loddon River catchment, one of the most intensively mined areas of the historical gold-rush period in Australia (1851-1914). Floodplain alluvium along the Loddon River was sampled to capture differences in metal and metalloid concentrations between the anthropogenic floodplain deposits and the underlying original floodplain. Elevated levels of arsenic up to 300 mg-As/kg were identified within the anthropogenic alluvial sediment, well above sediment guidelines (ISQG-high trigger value of 70 ppm) and substantially higher than in the pre-mining alluvium. Maximum arsenic concentrations were found at depth within the anthropogenic alluvium (plume-like), close to the contact with the original floodplain. The results obtained here indicate that arsenic may pose a significantly higher risk within this river catchment than previously assessed through analysis of surface floodplain soils. The risks of this submerged arsenic plume will require further investigation of its chemical form (speciation) to determine its mobility and potential bioavailability. Our work shows the long-lasting impact of historical gold mining on riverine landscapes.

Increase of Severe Pulmonary Infections in Adults Caused by M1UK Streptococcus pyogenes, Central Scotland, UK.

We characterized the epidemiology, host-pathogen characteristics, and outcomes of severe adult pulmonary Streptococcus pyogenes infections that coincided with a high community caseload in central Scotland, UK. The pulmonary infections had high illness and death rates and were associated with socioeconomic deprivation, influenza A co-infection, and the M1UK lineage of S. pyogenes.

Effect of the snake venom component crotamine on lymphatic endothelial cell responses and lymph transport.

OBJECTIVE: The pathology of snake envenomation is closely tied to the severity of edema in the tissue surrounding the area of the bite. Elucidating the mechanisms that promote the development of such severe edema is critical to a better understanding of how to treat this life-threatening injury. We focused on one of the most abundant venom components in North American viper venom, crotamine, and the effects it has on the cells and function of the lymphatic system. METHODS: We used RT-PCR to identify the location and relative abundance of crotamine's cellular targets (Kvα channels) within the tissues and cells of the lymphatic system. We used calcium flux, nitrate production, and cell morphometry to determine the effects of crotamine on lymphatic endothelial cells. We used tracer transport, node morphometry, and node deposition to determine the effects of crotamine on lymph transport in vivo. RESULTS: We found that genes that encode targets of crotamine are highly present in lymphatic tissues and cells and that there is a differential distribution of those genes that correlates with phasic contractile activity. We found that crotamine potentiates calcium flux in human dermal lymphatic endothelial cells in response to stimulation with histamine and sheer stress (but not alone) and that it alters the production of nitric oxide in response to shear as well as changes the level of F-actin polymerization of those same cells. Crotamine alters lymphatic transport of large molecular weight tracers to local lymph nodes and is deposited within the node mostly in the immediate subcapsular region. CONCLUSION: This evidence suggests that snake venom components may have an impact on the function of the lymphatic system. This needs to be studied in greater detail as there are numerous venom components that may have effects on aspects of the lymphatic system. This would not only provide basic information on the pathobiology of snakebite but also provide targets for improved therapeutics to treat snakebite.

An assessment of the downstream implications of blood culture collection and transit.

The implications of the variables within the pre-analytical phase of blood culture processing are poorly understood. This study aims to explore the effect of transit times (TT) and culture volume, on time to microbiological diagnosis and patient outcomes. Blood cultures received between 1st March and 31st July 2020/21 were identified. TT, time in incubator (TII), and for positive samples, request to positivity times (RPT) were calculated. Demographic details were recorded for all samples, and culture volume, length of stay (LoS), and 30-day mortality for patients with positive samples. Statistical analysis examined how culture volume and TT effected culture positivity and outcome; in the context of the 4-h national TT target. Totally, 14,375 blood culture bottles were received from 7367 patients; 988 (13.4%) were positive for organisms. There was no significant difference between TT of negative and positive samples. The RPT was significantly lower for samples with TT < 4 h (p < 0.001). Culture bottle volume did not affect RPT (p = 0.482) or TII (p = 0.367). A prolonged TT was associated with a longer length-of-stay in those with a bacteraemia with a significant organism (p = 0.001). We found shorter blood culture transportation time was associated with a significantly faster time of positive culture reporting, while optimal blood culture volume did not make a significant impact. Delays in reporting for significant organisms correspond to a prolonged LoS. Laboratory centralisation makes achieving the 4-h target a logistical challenge; however, this data suggests such targets have significant microbiological and clinical impacts.