Investigating the lignocellulolytic gut microbiome of huhu grubs (Prionoplus reticularis) using defined diets and dietary switch.

The huhu beetle (Prionoplus reticularis) is the largest endemic beetle found throughout Aotearoa New Zealand, and is characterised by feeding on wood during its larval stage. It has been hypothesised that its gut microbiome plays a fundamental role in the degradation of wood. To explore this idea we examined the fungal and bacterial community composition of huhu grubs' frass, using amplicon sequencing. Grubs were reared on an exclusive diet of either a predominantly cellulose source (cotton) or lignocellulose source (pine) for 4 months; subsequently a diet switch was performed and the grubs were grown for another 4 months. The fungal community of cellulose-reared huhu grubs was abundant in potential cellulose degraders, contrasting with the community of lignocellulose-reared grubs, which showed abundant potential soft rot fungi, yeasts, and hemicellulose and cellulose degraders. Cellulose-reared grubs showed a less diverse fungal community, however, diet switch from cellulose to lignocellulose resulted in a change in community composition that showed grubs were still capable of utilising this substrate. Conversely, diet seemed to have a limited influence on huhu grub gut bacterial communities.

A genus in the bacterial phylum Aquificota appears to be endemic to Aotearoa-New Zealand.

Allopatric speciation has been difficult to examine among microorganisms, with prior reports of endemism restricted to sub-genus level taxa. Previous microbial community analysis via 16S rRNA gene sequencing of 925 geothermal springs from the Taupo Volcanic Zone (TVZ), Aotearoa-New Zealand, revealed widespread distribution and abundance of a single bacterial genus across 686 of these ecosystems (pH 1.2-9.6 and 17.4-99.8 °C). Here, we present evidence to suggest that this genus, Venenivibrio (phylum Aquificota), is endemic to Aotearoa-New Zealand. A specific environmental niche that increases habitat isolation was identified, with maximal read abundance of Venenivibrio occurring at pH 4-6, 50-70 °C, and low oxidation-reduction potentials. This was further highlighted by genomic and culture-based analyses of the only characterised species for the genus, Venenivibrio stagnispumantis CP.B2T, which confirmed a chemolithoautotrophic metabolism dependent on hydrogen oxidation. While similarity between Venenivibrio populations illustrated that dispersal is not limited across the TVZ, extensive amplicon, metagenomic, and phylogenomic analyses of global microbial communities from DNA sequence databases indicates Venenivibrio is geographically restricted to the Aotearoa-New Zealand archipelago. We conclude that geographic isolation, complemented by physicochemical constraints, has resulted in the establishment of an endemic bacterial genus.

Contribution of soil bacteria to the atmosphere across biomes.

The dispersion of microorganisms through the atmosphere is a continual and essential process that underpins biogeography and ecosystem development and function. Despite the ubiquity of atmospheric microorganisms globally, specific knowledge of the determinants of atmospheric microbial diversity at any given location remains unresolved. Here we describe bacterial diversity in the atmospheric boundary layer and underlying soil at twelve globally distributed locations encompassing all major biomes, and characterise the contribution of local and distant soils to the observed atmospheric community. Across biomes the diversity of bacteria in the atmosphere was negatively correlated with mean annual precipitation but positively correlated to mean annual temperature. We identified distinct non-randomly assembled atmosphere and soil communities from each location, and some broad trends persisted across biomes including the enrichment of desiccation and UV tolerant taxa in the atmospheric community. Source tracking revealed that local soils were more influential than distant soil sources in determining observed diversity in the atmosphere, with more emissive semi-arid and arid biomes contributing most to signatures from distant soil. Our findings highlight complexities in the atmospheric microbiota that are relevant to understanding regional and global ecosystem connectivity.

Forecasting the future of life in Antarctica.

Antarctic ecosystems are under increasing anthropogenic pressure, but efforts to predict the responses of Antarctic biodiversity to environmental change are hindered by considerable data challenges. Here, we illustrate how novel data capture technologies provide exciting opportunities to sample Antarctic biodiversity at wider spatiotemporal scales. Data integration frameworks, such as point process and hierarchical models, can mitigate weaknesses in individual data sets, improving confidence in their predictions. Increasing process knowledge in models is imperative to achieving improved forecasts of Antarctic biodiversity, which can be attained for data-limited species using hybrid modelling frameworks. Leveraging these state-of-the-art tools will help to overcome many of the data scarcity challenges presented by the remoteness of Antarctica, enabling more robust forecasts both near- and long-term.

The spatial distribution and biogeochemical drivers of nitrogen cycle genes in an Antarctic desert.

Antarctic deserts, such as the McMurdo Dry Valleys (MDV), represent extremely cold and dry environments. Consequently, MDV are suitable for studying the environment limits on the cycling of key elements that are necessary for life, like nitrogen. The spatial distribution and biogeochemical drivers of nitrogen-cycling pathways remain elusive in the Antarctic deserts because most studies focus on specific nitrogen-cycling genes and/or organisms. In this study, we analyzed metagenome and relevant environmental data of 32 MDV soils to generate a complete picture of the nitrogen-cycling potential in MDV microbial communities and advance our knowledge of the complexity and distribution of nitrogen biogeochemistry in these harsh environments. We found evidence of nitrogen-cycling genes potentially capable of fully oxidizing and reducing molecular nitrogen, despite the inhospitable conditions of MDV. Strong positive correlations were identified between genes involved in nitrogen cycling. Clear relationships between nitrogen-cycling pathways and environmental parameters also indicate abiotic and biotic variables, like pH, water availability, and biological complexity that collectively impose limits on the distribution of nitrogen-cycling genes. Accordingly, the spatial distribution of nitrogen-cycling genes was more concentrated near the lakes and glaciers. Association rules revealed non-linear correlations between complex combinations of environmental variables and nitrogen-cycling genes. Association rules for the presence of denitrification genes presented a distinct combination of environmental variables from the remaining nitrogen-cycling genes. This study contributes to an integrative picture of the nitrogen-cycling potential in MDV.

Unique Geothermal Chemistry Shapes Microbial Communities on Mt. Erebus, Antarctica.

Mt. Erebus, Antarctica, is the world's southernmost active volcano and is unique in its isolation from other major active volcanic systems and its distinctive geothermal systems. Using 16S rRNA gene amplicon sequencing and physicochemical analyses, we compared samples collected at two contrasting high-temperature (50°C-65°C) sites on Mt. Erebus: Tramway Ridge, a weather-protected high biomass site, and Western Crater, an extremely exposed low biomass site. Samples were collected along three thermal gradients, one from Western Crater and two within Tramway Ridge, which allowed an examination of the heterogeneity present at Tramway Ridge. We found distinct soil compositions between the two sites, and to a lesser extent within Tramway Ridge, correlated with disparate microbial communities. Notably, pH, not temperature, showed the strongest correlation with these differences. The abundance profiles of several microbial groups were different between the two sites; class Nitrososphaeria amplicon sequence variants (ASVs) dominated the community profiles at Tramway Ridge, whereas Acidobacteriotal ASVs were only found at Western Crater. A co-occurrence network, paired with physicochemical analyses, allowed for finer scale analysis of parameters correlated with differential abundance profiles, with various parameters (total carbon, total nitrogen, soil moisture, soil conductivity, sulfur, phosphorous, and iron) showing significant correlations. ASVs assigned to Chloroflexi classes Ktedonobacteria and Chloroflexia were detected at both sites. Based on the known metabolic capabilities of previously studied members of these groups, we predict that chemolithotrophy is a common strategy in this system. These analyses highlight the importance of conducting broader-scale metagenomics and cultivation efforts at Mt. Erebus to better understand this unique environment.

A Pilot Quality Improvement Project to Reduce Intraoperative MRI Hypothermia in Neurosurgical Patients.

Intraoperative hypothermia increases patient morbidity, including bleeding and infection risk. Neurosurgical intraoperative magnetic resonance imaging (iMRI) can lead to hypothermia from patient exposure and low ambient temperature in the MRI suite. This quality improvement project aimed to reduce the risk of hypothermia during pediatric neurosurgery laser ablation procedures with iMRI. The primary aim was to increase the mean lowest core temperature in pediatric patients with epilepsy during iMRI procedures by 1 °C from a baseline mean lowest core temperature of 34.2 ± 1.2 °C within 10 months and sustain for 10 months. Methods: This report is a single-institution quality improvement project from March 2019 to June 2021, with 21 patients treated at a pediatric hospital. After identifying key drivers, temperature-warming interventions were instituted to decrease hypothermia among patients undergoing iMRI during neurosurgery procedures. A multidisciplinary team of physicians, nurses, and MRI technologists convened for huddles before each case. Interventions included prewarmed operating rooms (ORs), blanket coverings, MRI table and room; forced-air blanket warming, temperature monitoring in the OR and iMRI environments; and the MRI fan turned off. Results: Data were analyzed for five patients before and nine patients after the institution of the temperature-warming elements. The sustainment period included 15 patients. The mean lowest intraoperative temperature rose from 34.2 ± 1.3 °C in the preintervention period to 35.5 ± 0.6 °C in sustainment (P = 0.004). Conclusion: Hybrid OR and MRI procedures increase hypothermia risk, which increases patient morbidity. Implementation of a multidisciplinary, multi-item strategy for patient warming mitigates the risk.

Gastric Band Insertion to Revise Sleeve Gastrectomy: A Case Report.

Bariatric surgery for the treatment of obesity, first introduced in the 1950s and 1960s, is now relatively commonplace. Often patients will first have an adjustable gastric band inserted, as this does not require altering or removing parts of the gastrointestinal tract. This procedure is associated with short hospital stays and quick recoveries and may be adjusted without further surgery. Typically only after banding fails mechanically or fails to bring about a satisfactory reduction in body mass index (BMI) do patients undergo further bariatric procedures which involve altering or removing parts of the gastrointestinal tract. Recent research has suggested that gastric banding is associated with greater weight reduction results as a secondary or follow-up procedure following a failed initial bariatric surgery. Here we report the case of a 43-year-old female with a history of cryptogenic organizing pneumonitis, gastroesophageal reflux disease (GERD), asthma, obesity, and prior sleeve gastrectomy who underwent a laparoscopic gastric band insertion to revise the prior sleeve gastrectomy, in reverse of the typical sequence of bariatric surgeries.

Chronic Appendicitis, the Lesser-Known Form of Appendiceal Inflammation: A Case Report.

Chronic appendicitis is a rare condition involving appendiceal inflammation as these conditions typically present acutely and are treated with appendectomy. However, in a small minority of patients, appendicitis can have a mild presentation and become recurrent or chronic appendicitis. Due to the acute nature and immediate treatment of patients presenting with typical symptoms of appendicitis, chronic appendicitis has been often overlooked and/or misdiagnosed. We present a case in which a 50-year-old male presented with right lower quadrant (RLQ) pain of one-month duration. Computed tomography (CT) imaging showed evidence of lymph node enlargement near the patient's appendix, raising suspicion of chronic appendicitis. The patient underwent a successful laparoscopic appendectomy.

Peanut-Related Perforated Diverticulitis Before the Age of 60.

We present a case in which a 55-year-old male with a past medical history of systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) presented with sharp, worsening right-sided abdominal pain radiating across the entire abdomen after eating peanuts. Computed tomography (CT) imaging showed evidence of acute sigmoid diverticulitis complicated by a walled-off perforation. The patient's past medical history suggested previous recurrent episodes of diverticulitis. Our patient underwent exploratory laparotomy, sigmoid colon resection with low anterior anastomosis and proctocolectomy, and loop ileostomy. During treatment, the sigmoid colon was found to be very indurated and abnormally going all the way down to the peritoneal reflection. Appropriate identification of the patient's condition and timely intervention resulted in a successful outcome.

Biogeochemical feedbacks to ocean acidification in a cohesive photosynthetic sediment.

Ecosystem feedbacks in response to ocean acidification can amplify or diminish diel pH oscillations in productive coastal waters. Benthic microalgae generate such oscillations in sediment porewater and here we ask how CO2 enrichment (acidification) of the overlying seawater alters these in the absence and presence of biogenic calcite. We placed a 1-mm layer of ground oyster shells, mimicking the arrival of dead calcifying biota (+Calcite), or sand (Control) onto intact silt sediment cores, and then gradually increased the pCO2 in the seawater above half of +Calcite and Control cores from 472 to 1216 µatm (pH 8.0 to 7.6, CO2:HCO3- from 4.8 to 9.6 × 10-4). Porewater [O2] and [H+] microprofiles measured 16 d later showed that this enrichment had decreased the O2 penetration depth (O2-pd) in +Calcite and Control, indicating a metabolic response. In CO2-enriched seawater: (1) sediment biogeochemical processes respectively added and removed more H+ to and from the sediment porewater in darkness and light, than in ambient seawater increasing the amplitude of the diel porewater [H+] oscillations, and (2) in darkness, calcite dissolution in +Calcite sediment decreased the porewater [H+] below that in overlying seawater, reversing the sediment-seawater H+ flux and decreasing the amplitude of diel [H+] oscillations. This dissolution did not, however, counter the negative effect of CO2 enrichment on O2-pd. We now hypothesise that feedback to CO2 enrichment-an increase in the microbial reoxidation of reduced solutes with O2-decreased the sediment O2-pd and contributed to the enhanced porewater acidification.

Composite Vascularized Autograft Elbow Transplant: A Case Report.

CASE: A 37-year-old man presented with an absent right elbow joint secondary to trauma, subsequent ankylosis, total elbow arthroplasty (TEA), and TEA explantation after infection. The patient also had a contralateral complete brachial plexus injury, but an intact elbow joint. Given that the patient had a functional right hand/wrist, composite vascularized autograft elbow transplant was performed from left to right upper extremity. Four years postoperatively, the patient could independently complete activities of daily living. CONCLUSION: This case is the first to report composite vascularized autograft elbow transplant. Although indications are limited, this case illuminates novel uses of standard techniques for a difficult problem.

Microbial Succession under Freeze-Thaw Events and Its Potential for Hydrocarbon Degradation in Nutrient-Amended Antarctic Soil.

The polar regions have relatively low richness and diversity of plants and animals, and the basis of the entire ecological chain is supported by microbial diversity. In these regions, understanding the microbial response against environmental factors and anthropogenic disturbances is essential to understand patterns better, prevent isolated events, and apply biotechnology strategies. The Antarctic continent has been increasingly affected by anthropogenic contamination, and its constant temperature fluctuations limit the application of clean recovery strategies, such as bioremediation. We evaluated the bacterial response in oil-contaminated soil through a nutrient-amended microcosm experiment using two temperature regimes: (i) 4 °C and (ii) a freeze-thaw cycle (FTC) alternating between -20 and 4 °C. Bacterial taxa, such as Myxococcales, Chitinophagaceae, and Acidimicrobiales, were strongly related to the FTC. Rhodococcus was positively related to contaminated soils and further stimulated under FTC conditions. Additionally, the nutrient-amended treatment under the FTC regime enhanced bacterial groups with known biodegradation potential and was efficient in removing hydrocarbons of diesel oil. The experimental design, rates of bacterial succession, and level of hydrocarbon transformation can be considered as a baseline for further studies aimed at improving bioremediation strategies in environments affected by FTC regimes.

Gene expression profiling of brain endothelial cells after experimental subarachnoid haemorrhage.

Subarachnoid haemorrhage (SAH) is a type of hemorrhagic stroke that is associated with high morbidity and mortality. New effective treatments are needed to improve outcomes. The pathophysiology of SAH is complex and includes early brain injury and delayed cerebral ischemia, both of which are characterized by blood-brain barrier (BBB) impairment. We isolated brain endothelial cells (BECs) from mice subjected to SAH by injection of blood into the prechiasmatic cistern. We used gene expression profiling to identify 707 unique genes (2.8% of transcripts, 403 upregulated, 304 downregulated, 24,865 interrogated probe sets) that were significantly differentially expressed in mouse BECs after SAH. The pathway involving prostaglandin synthesis and regulation was significantly upregulated after SAH, including increased expression of the Ptgs2 gene and its corresponding COX-2 protein. Celecoxib, a selective COX-2 inhibitor, limited upregulation of Ptgs2 in BECs. In this study, we have defined the gene expression profiling of BECs after experimental SAH and provide further insight into BBB pathophysiology, which may be relevant to other neurological diseases such as traumatic brain injury, brain tumours, ischaemic stroke, multiple sclerosis, and neurodegenerative disorders.

Persistent Small Bowel Obstruction due to Small Bowel Adenocarcinoma: A Case Report.

Small bowel obstruction (SBO), of both partial and complete types, is a condition predominantly caused by intra-abdominal adhesions and hernias. However, a known but very uncommon cause of SBO is malignancies, which are more complicated than those caused by adhesions and hernias, and associated with poorer prognoses; of these, small bowel adenocarcinoma is an even rarer etiology of SBO. The majority of SBO cases that are treated have resolution of symptoms and do not have recurrence/persistence of the condition; however, reports suggest that approximately one-fifth of SBO cases that are treated will result in recurrence/persistence of SBO requiring repeat admission. Here we report the case of an 89-year-old female with a past medical history of right lower extremity deep venous thrombosis, inferior vena cava filter placement, iron deficiency anemia, diverticular disease, internal hemorrhoids, sick sinus syndrome, emphysema, hypertension, dyslipidemia, and hypothyroidism, who presented with diarrhea and intermittent dark stool. Abdominal computed tomography (CT) while in the emergency department initially showed possible ischemic bowel and SBO. After an exploratory laparotomy with small bowel resection and adhesiolysis, pathological analysis of a resected specimen showed infiltrating small bowel adenocarcinoma. Persistence of symptoms necessitated subsequent abdominal imaging, which demonstrated persistent SBO, which was treated with a second exploratory laparotomy with small bowel resection and end ileostomy.

Cholecystoduodenal Fistula Evading Imaging and Endoscopic Retrograde Cholangiopancreatography: A Case Report.

Cholecystoduodenal fistulas are a type of internal biliary fistula that occur due to chronic inflammation of the gallbladder/biliary tree; if left untreated, perforation and necrosis can occur. Cholecystoduodenal fistulas are often difficult to diagnose due to their non-specific signs and symptoms. Since the widespread use of techniques such as magnetic resonance cholangiopancreatography and imaging modalities such as computed tomography, the frequency of reports describing intraoperative cholecystoduodenal fistula has reduced dramatically. Here, we report the case of a 54-year-old female who presented with a two-day history of non-radiating epigastric abdominal pain, initially diagnosed with acute cholecystitis and choledocholithiasis. Upon undergoing laparoscopic cholecystectomy, she was found to have extensive fibrosis of the gallbladder, adhesions, and an impacted gallstone in the wall of the gallbladder. Imaging and endoscopic retrograde cholangiopancreatography performed prior to surgery did not detect a cholecystoduodenal fistula that was discovered intraoperatively. She was treated successfully with laparoscopic cholecystectomy and repair of the duodenum.

Geochemically Defined Space-for-Time Transects Successfully Capture Microbial Dynamics Along Lacustrine Chronosequences in a Polar Desert.

The space-for-time substitution approach provides a valuable empirical assessment to infer temporal effects of disturbance from spatial gradients. Applied to predict the response of different ecosystems under current climate change scenarios, it remains poorly tested in microbial ecology studies, partly due to the trophic complexity of the ecosystems typically studied. The McMurdo Dry Valleys (MDV) of Antarctica represent a trophically simple polar desert projected to experience drastic changes in water availability under current climate change scenarios. We used this ideal model system to develop and validate a microbial space-for-time sampling approach, using the variation of geochemical profiles that follow alterations in water availability and reflect past changes in the system. Our framework measured soil electrical conductivity, pH, and water activity in situ to geochemically define 17 space-for-time transects from the shores of four dynamic and two static Dry Valley lakes. We identified microbial taxa that are consistently responsive to changes in wetness in the soils and reliably associated with long-term dry or wet edaphic conditions. Comparisons between transects defined at static (open-basin) and dynamic (closed-basin) lakes highlighted the capacity for geochemically defined space-for-time gradients to identify lasting deterministic impacts of historical changes in water presence on the structure and diversity of extant microbial communities. We highlight the potential for geochemically defined space-for-time transects to resolve legacy impacts of environmental change when used in conjunction with static and dynamic scenarios, and to inform future environmental scenarios through changes in the microbial community structure, composition, and diversity.

A core phyllosphere microbiome exists across distant populations of a tree species indigenous to New Zealand.

The phyllosphere microbiome is increasingly recognised as an influential component of plant physiology, yet it remains unclear whether stable host-microbe associations generally exist in the phyllosphere. Leptospermum scoparium (manuka) is a tea tree indigenous to New Zealand, and honey derived from manuka is widely known to possess unique antimicrobial properties. However, the host physiological traits associated with these antimicrobial properties vary widely, and the specific cause of such variation has eluded scientists despite decades of research. Notably, the manuka phyllosphere microbiome remains uncharacterised, and its potential role in mediating host physiology has not been considered. Working within the prevailing core microbiome conceptual framework, we hypothesise that the phyllosphere microbiome of manuka exhibits specific host association patterns congruent with those of a microbial community under host selective pressure (null hypothesis: the manuka phyllosphere microbiome is recruited stochastically from the surrounding environment). To examine our hypothesis, we characterised the phyllosphere and associated soil microbiomes of five distinct and geographically distant manuka populations across the North Island of New Zealand. We identified a habitat-specific and relatively abundant core microbiome in the manuka phyllosphere, which was persistent across all samples. In contrast, non-core phyllosphere microorganisms exhibited significant variation across individual host trees and populations that was strongly driven by environmental and spatial factors. Our results demonstrate the existence of a dominant and ubiquitous core microbiome in the phyllosphere of manuka, supporting our hypothesis that phyllosphere microorganisms of manuka exhibit specific host association and potentially mediate physiological traits of this nationally and culturally treasured indigenous plant. In addition, our results illustrate biogeographical patterns in manuka phyllosphere microbiomes and offer insight into factors contributing to phyllosphere microbiome assembly.

Abiotic factors influence patterns of bacterial diversity and community composition in the Dry Valleys of Antarctica.

The Dry Valleys of Antarctica are a unique ecosystem of simple trophic structure, where the abiotic factors that influence soil bacterial communities can be resolved in the absence of extensive biotic interactions. This study evaluated the degree to which aspects of topographic, physicochemical and spatial variation explain patterns of bacterial richness and community composition in 471 soil samples collected across a 220 square kilometer landscape in Southern Victoria Land. Richness was most strongly influenced by physicochemical soil properties, particularly soil conductivity, though significant trends with several topographic and spatial variables were also observed. Structural equation modeling (SEM) supported a final model in which variation in community composition was best explained by physicochemical variables, particularly soil water content, and where the effects of topographic variation were largely mediated through their influence on physicochemical variables. Community dissimilarity increased with distance between samples, and though most of this variation was explained by topographic and physicochemical variation, a small but significant relationship remained after controlling for this environmental variation. As the largest survey of terrestrial bacterial communities of Antarctica completed to date, this work provides fundamental knowledge of the Dry Valleys ecosystem, and has implications globally for understanding environmental factors that influence bacterial distributions.