Multiple origins of obligate nematode and insect symbionts by a clade of bacteria closely related to plant pathogens.

Obligate symbioses involving intracellular bacteria have transformed eukaryotic life, from providing aerobic respiration and photosynthesis to enabling colonization of previously inaccessible niches, such as feeding on xylem and phloem, and surviving in deep-sea hydrothermal vents. A major challenge in the study of obligate symbioses is to understand how they arise. Because the best studied obligate symbioses are ancient, it is especially challenging to identify early or intermediate stages. Here we report the discovery of a nascent obligate symbiosis in Howardula aoronymphium, a well-studied nematode parasite of Drosophila flies. We have found that Haoronymphium and its sister species harbor a maternally inherited intracellular bacterial symbiont. We never find the symbiont in nematode-free flies, and virtually all nematodes in the field and the laboratory are infected. Treating nematodes with antibiotics causes a severe reduction in fly infection success. The association is recent, as more distantly related insect-parasitic tylenchid nematodes do not host these endosymbionts. We also report that the Howardula nematode symbiont is a member of a widespread monophyletic group of invertebrate host-associated microbes that has independently given rise to at least four obligate symbioses, one in nematodes and three in insects, and that is sister to Pectobacterium, a lineage of plant pathogenic bacteria. Comparative genomic analysis of this group, which we name Candidatus Symbiopectobacterium, shows signatures of genome erosion characteristic of early stages of symbiosis, with the Howardula symbiont's genome containing over a thousand predicted pseudogenes, comprising a third of its genome.

A highly divergent Wolbachia with a tiny genome in an insect-parasitic tylenchid nematode.

Wolbachia symbionts are the most successful host-associated microbes on the planet, infecting arthropods and nematodes. Their role in nematodes is particularly enigmatic, with filarial nematode species either 100% infected and dependent on symbionts for reproduction and development, or not at all infected. We have discovered a highly divergent strain of Wolbachia in an insect-parasitic tylenchid nematode, Howardula sp., in a nematode clade that has not previously been known to harbour Wolbachia. While this nematode is 100% infected with Wolbachia, we did not detect it in related species. We sequenced the Howardula symbiont (wHow) genome and found that it is highly reduced, comprising only 550 kilobase pairs of DNA, approximately 35% smaller than the smallest Wolbachia nematode symbiont genomes. The wHow genome is a subset of all other Wolbachia genomes and has not acquired any new genetic information. While it has lost many genes, including genes involved in cell wall synthesis and cell division, it has retained the entire haem biosynthesis pathway, suggesting that haem supplementation is critical. wHow provides key insights into our understanding of what are the lower limits of Wolbachia cells, as well as the role of Wolbachia symbionts in the biology and convergent evolution of diverse parasitic nematodes.

The Sacred Ibis debate: The first test of evolution.

In 1798, Napoleon Bonaparte's army invaded Egypt, returning with many treasures including large numbers of Sacred Ibis mummies. The ancient Egyptians revered the ibis and mummified literally millions of them. The French naturalist Georges Cuvier used these mummies to challenge an emerging idea of the time, namely Jean-Baptiste Lamarck's theory of evolution. Cuvier detected no measurable differences between mummified Sacred Ibis and contemporary specimens of the same species. Consequently, he argued that this was evidence for the "fixity of species." The "Sacred Ibis debate" predates the so-called "Great Debate" between Cuvier and Geoffroy Saint-Hilaire and the publication of Darwin's On the Origin of Species five decades later. Cuvier's views and his study had a profound influence on the scientific and public perception of evolution, setting back the acceptance of evolutionary theory in Europe for decades.

AI-deploying organizations are key to addressing 'perfect storm' of AI risks.

We argue that a perfect storm of five conditions heightens the risk of harm to society from artificial intelligence: (1) the powerful, invisible nature of AI, (2) low public awareness and AI literacy, (3) rapid scaled deployment of AI, (4) insufficient regulation, and (5) the gap between trustworthy AI principles and practices. To prevent harm, fit-for-purpose regulation and public AI literacy programs have been recommended, but education and government regulation will not be sufficient: AI-deploying organizations need to play a central role in creating and deploying trustworthy AI in line with the principles of trustworthy AI, and taking accountability to mitigate the risks.

Dynamic changes in Wolbachia infection over a single generation of Drosophila suzukii, across a wide range of resource availability.

Wolbachia bacteria are maternally inherited symbionts that commonly infect terrestrial arthropods. Many Wolbachia reach high frequencies in their hosts by manipulating their reproduction, for example by causing reproductive incompatibilities between infected male and uninfected female hosts. However, not all strains manipulate reproduction, and a key unresolved question is how these non-manipulative Wolbachia persist in their hosts, often at intermediate to high frequencies. One such strain, wSuz, infects the invasive fruit pest Drosophila suzukii, spotted-wing drosophila. Here, we tested the hypothesis that wSuz infection provides a competitive benefit when resources are limited. Over the course of one season, we established population cages with varying amounts of food in a semi-field setting and seeded them with a 50:50 mixture of flies with and without Wolbachia. We predicted that Wolbachia-infected individuals should have higher survival and faster development than their uninfected counterparts when there was little available food. We found that while food availability strongly impacted fly fitness, there was no difference in development times or survival between Wolbachia-infected and uninfected flies. Interestingly, however, Wolbachia infection frequencies changed dramatically, with infections either increasing or decreasing by as much as 30% in a single generation, suggesting the possibility of unidentified factors shaping Wolbachia infection over the course of the season.

Genetic diversity despite population collapse in a critically endangered marine fish: the smalltooth sawfish (Pristis pectinata).

Sawfish (family Pristidae) are among the most critically endangered marine fish in the world, yet very little is known about how genetic bottlenecks, genetic drift, and inbreeding depression may be affecting these elasmobranchs. In the US Atlantic, the smalltooth sawfish (Pristis pectinata) has declined to 1-5% of its abundance in the 1900s, and its core distribution has contracted to southwest Florida. We used 8 polymorphic microsatellite markers to show that this remnant population still exhibits high genetic diversity in terms of average allelic richness (18.23), average alleles per locus (18.75, standard deviation [SD] 6.6) and observed heterozygosity (0.43-0.98). Inbreeding is rare (mean individual internal relatedness = -0.02, SD 0.14; F(IS) = -0.011, 95% confidence interval [CI] = -0.039 to 0.011), even though the estimated effective population size (N(e)) is modest (250-350, 95% CI = 142-955). Simulations suggest that the remnant smalltooth sawfish population will probably retain >90% of its current genetic diversity over the next century even at the lower estimate of N(e). There is no evidence of a genetic bottleneck accompanying last century's demographic bottleneck, and we discuss hypotheses that could explain this. We also discuss features of elasmobranch life history and population biology that could make them less vulnerable than other large marine vertebrates to genetic change associated with reduced population size.

Pleistocene population expansions of Antarctic seals.

We sequenced a portion (c. 475 bp) of the mitochondrial control region of three species of Antarctic phocid carnivores (Weddell seal, Leptonychotes weddellii, N = 181; crabeater seal, Lobodon carcinophaga, N = 143; and Ross seal, Ommatophoca rossii, N = 41) that live seasonally or permanently in the fast ice and seasonal pack ice of the western Amundsen and Ross seas of western Antarctica. We resolved 251 haplotypes with a haplotype diversity of 0.98 to 0.99. Bayesian estimates of Theta from the program LAMARC ranged from 0.075 for Weddell seals to 0.576 for crabeater seals. We used the values of theta to estimate female effective population sizes (N(EF)), which were 40,700 to 63,000 for Weddell seals, 44,400 to 97,800 for Ross seals, and 358,500 to 531,900 for crabeater seals. We used mismatch distributions to test for historical population size expansions. Weddell seals and crabeater seals had significant, unimodal mean pairwise difference distributions (P = 0.56 and 0.36, respectively), suggesting that their populations expanded suddenly around 731,000 years ago (Weddell seals) and around 1.6 million years ago (crabeater seals). Both of these expansions occurred during times of intensified glaciations and may have been fostered by expanding pack ice habitat.

Compounding parenteral nutrition: reducing the risks.

Compounding parenteral nutrition, either manually or with an automated compounding device, requires aseptic conditions and trained personnel. The revised version of United States Pharmacopeia Chapter <797> is a comprehensive document that describes standards and procedures to minimize the risk of contamination of compounded parenteral products. The chapter includes evidence-based instructions for pharmacy design, washing, garbing, cleaning, quality assurance, and personnel training and evaluation designed to improve compounding practices in all pharmacies that compound parenteral products. Because parenteral nutrition is a compounded product mixed from multiple additives, it is important to maintain these standards, especially when using an automated compounding device. This article is an overview of United States Pharmacopeia Chapter <797>, with special emphasis on parenteral nutrition.

Mitogenomic diversity in Sacred Ibis Mummies sheds light on early Egyptian practices.

The ancient catacombs of Egypt harbor millions of well-preserved mummified Sacred Ibis (Threskiornis aethiopicus) dating from ~600BC. Although it is known that a very large number of these 'votive' mummies were sacrificed to the Egyptian God Thoth, how the ancient Egyptians obtained millions of these birds for mummification remains unresolved. Ancient Egyptian textual evidences suggest they may have been raised in dedicated large-scale farms. To investigate the most likely method used by the priests to secure birds for mummification, we report the first study of complete mitochondrial genomes of 14 Sacred Ibis mummies interred ~2500 years ago. We analysed and compared the mitogenomic diversity among Sacred Ibis mummies to that found in modern Sacred Ibis populations from throughout Africa. The ancient birds show a high level of genetic variation comparable to that identified in modern African populations, contrary to the suggestion in ancient hieroglyphics (or ancient writings) of centralized industrial scale farming of sacrificial birds. This suggests a sustained short-term taming of the wild migratory Sacred Ibis for the ritual yearly demand.

Technology in Parenteral Nutrition Compounding.

Technology is constantly being used in novel ways, and its use in the practice of medicine is no exception. Examples of this include computer physician order entry, barcode-medication scanning, electronic health records (EHRs), and bedside patient charts, to name a few. Compounding parenteral nutrition has been included in this technological revolution, with improvements such as barcode-assisted medication preparation systems and EHR-to-compounder interfaces. Along with some of these electronic advancements come the inevitable improvements and challenges, which are explored in this article.

Genetics and Genomics of an Unusual Selfish Sex Ratio Distortion in an Insect.

Diverse selfish genetic elements have evolved the ability to manipulate reproduction to increase their transmission, and this can result in highly distorted sex ratios [1]. Indeed, one of the major explanations for why sex determination systems are so dynamic is because they are shaped by ongoing coevolutionary arms races between sex-ratio-distorting elements and the rest of the genome [2]. Here, we use genetic crosses and genome analysis to describe an unusual sex ratio distortion with striking consequences on genome organization in a booklouse species, Liposcelis sp. (Insecta: Psocodea), in which two types of females coexist. Distorter females never produce sons but must mate with males (the sons of nondistorting females) to reproduce [3]. Although they are diploid and express the genes inherited from their fathers in somatic tissues, distorter females only ever transmit genes inherited from their mothers. As a result, distorter females have unusual chimeric genomes, with distorter-restricted chromosomes diverging from their nondistorting counterparts and exhibiting features of a giant non-recombining sex chromosome. The distorter-restricted genome has also acquired a gene from the bacterium Wolbachia, a well-known insect reproductive manipulator; we found that this gene has independently colonized the genomes of two other insect species with unusual reproductive systems, suggesting possible roles in sex ratio distortion in this remarkable genetic system.

Nutrition support in pancreatitis.

Nutrition support is especially important in patients who have pancreatitis, as these patients have high metabolic needs and are usually unable to ingest sufficient calories from an oral diet because of pain or intestinal dysfunction. Clinicians must assess severity of the disease carefully, as initiation and timing of nutrition support are crucial. Depending on the severity, early nutrition support may be unnecessary, while late support ultimately may lead to worse outcomes. Route of nutrition support also plays an important role in treatment. The clinician has many alternatives from which to choose, including enteral nutrition given nasogastrically or nasojejunally, or parenteral nutrition given through a central line. This article explores the role of nutrition support in the outcome of pancreatitis and provides guidelines to aid the clinician in caring for patients who have acute and chronic pancreatitis.

Paternal Genome Elimination in Liposcelis Booklice (Insecta: Psocodea).

How sex is determined in insects is diverse and dynamic, and includes male heterogamety, female heterogamety, and haplodiploidy. In many insect lineages, sex determination is either completely unknown or poorly studied. We studied sex determination in Psocodea-a species-rich order of insects that includes parasitic lice, barklice, and booklice. We focus on a recently discovered species of Liposcelis booklice (Psocodea: Troctomorpha), which are among the closest free-living relatives of parasitic lice. Using genetic, genomic, and immunohistochemical approaches, we show that this group exhibits paternal genome elimination (PGE), an unusual mode of sex determination that involves genomic imprinting. Controlled crosses, following a genetic marker over multiple generations, demonstrated that males only transmit to offspring genes they inherited from their mother. Immunofluorescence microscopy revealed densely packed chromocenters associated with H3K9me3-a conserved marker for heterochromatin-in males, but not in females, suggesting silencing of chromosomes in males. Genome assembly and comparison of read coverage in male and female libraries showed no evidence for differentiated sex chromosomes. We also found that females produce more sons early in life, consistent with facultative sex allocation. It is likely that PGE is widespread in Psocodea, including human lice. This order represents a promising model for studying this enigmatic mode of sex determination.

An Institutional Change in Continuous Renal Replacement Therapy: Nutrition Support Team Resolves Resultant Severe Hypophosphatemia.

BACKGROUND: Critically ill patients with acute kidney injury may require parenteral nutrition (PN) and continuous renal replacement therapy (CRRT). Introduction of a phosphate-free premixed renal replacement fluid without system-wide education in May 2011 resulted in increased incidence of hypophosphatemia, necessitating change in practice. Changes included (1) maximizing phosphate in PN, (2) modifying the CRRT order set, and (3) developing a CRRT competency evaluation for nutrition support team members. This study evaluates the effect of these changes on the incidence of hypophosphatemia. METHODS: Phosphate levels and predicated probability of hypophosphatemia were evaluated for patients receiving PN and CRRT over 3 time periods: prior to implementing the changes (preimplementation), during change implementation (intermediate), and following implementation (postimplementation). Hypophosphatemia was defined as a serum phosphate level <2.5 mg/dL. Generalized linear mixed models were applied for statistical analysis. RESULTS: The retrospective study includes 336 measures from 49 patients. Patients in the intermediate and postimplementation periods were not significantly different from each other and had significantly higher mean phosphate levels than patients in the preimplementation period (P < .0001). They were also less likely to develop hypophosphatemia compared with preimplementation patients (intermediate: odds ratio [OR], 0.07; 95% confidence interval [CI], 0.03-0.18, P < .0001; postimplementation: OR, 0.09; 95% CI, 0.03-0.27, P < .0001). CONCLUSIONS: Modifications in phosphate dosing together with CRRT education reduced the incidence of hypophosphatemia in PN patients receiving CRRT. Communication of significant changes in clinical care should be shared with all services prior to implementation. Communication and planning between services caring for complex patients are necessary to prevent systems-based problems.

An Institutional Change in Continuous Renal Replacement Therapy.

BACKGROUND: Critically ill patients with acute kidney injury may require parenteral nutrition (PN) and continuous renal replacement therapy (CRRT). Introduction of a phosphate-free premixed renal replacement fluid without system-wide education in May 2011 resulted in increased incidence of hypophosphatemia, necessitating change in practice. Changes included (1) maximizing phosphate in PN, (2) modifying the CRRT order set, and (3) developing a CRRT competency evaluation for nutrition support team members. This study evaluates the effect of these changes on the incidence of hypophosphatemia. METHODS: Phosphate levels and predicated probability of hypophosphatemia were evaluated for patients receiving PN and CRRT over 3 time periods: prior to implementing the changes (preimplementation), during change implementation (intermediate), and following implementation (postimplementation). Hypophosphatemia was defined as a serum phosphate level <2.5 mg/dL. Generalized linear mixed models were applied for statistical analysis. RESULTS: The retrospective study includes 336 measures from 49 patients. Patients in the intermediate and postimplementation periods were not significantly different from each other and had significantly higher mean phosphate levels than patients in the preimplementation period ( P < .0001). They were also less likely to develop hypophosphatemia compared with preimplementation patients (intermediate: odds ratio [OR], 0.07; 95% confidence interval [CI], 0.03-0.18, P < .0001; postimplementation: OR, 0.09; 95% CI, 0.03-0.27, P < .0001). CONCLUSIONS: Modifications in phosphate dosing together with CRRT education reduced the incidence of hypophosphatemia in PN patients receiving CRRT. Communication of significant changes in clinical care should be shared with all services prior to implementation. Communication and planning between services caring for complex patients are necessary to prevent systems-based problems.

Use of Premixed Parenteral Nutrition During a Phosphate Shortage in a Non-Critically Ill Population.

BACKGROUND: Drug shortages pose prescribing problems to clinicians. During fiscal year (FY) 2014, an acute shortage of intravenous potassium phosphate (K-Phos IV), a common supplement in parenteral nutrition (PN), prompted the use of premixed instead of individualized PN to conserve K-Phos IV. Here we quantify the K-Phos IV conserved by using premixed PN and the associated cost differences. MATERIALS AND METHODS: Costs of preparing premixed PN vs individualized PN of equivalent composition were calculated for FY 2014 at a single-center tertiary care facility. Quantity and cost of K-Phos IV saved were calculated based on the number of premixed PN prescriptions. Costs for FY 2015 were projected based on drug costs from July 2014. RESULTS: During FY 2014, prescribing premixed in lieu of individualized PN conserved 16,440 mmol K-Phos IV but increased the cost of PN by $4080.45. However, increases in K-Phos IV cost at the end of FY 2014 resulted in premixed PN as a relatively less expensive therapy than individualized PN for our institution. Cost savings of $7092.20 due to use of premixed PN is projected for FY 2015. CONCLUSIONS: Prescribing premixed PN conserves K-Phos IV during shortages, but it increased direct drug spending in non-critically ill patients at our institution during FY 2014. Persistent shortages can drive market costs of K-Phos IV, however, necessitating frequent reconsideration of resource utilization.

Use of Piggyback Electrolytes for Patients Receiving Individually Prescribed vs Premixed Parenteral Nutrition.

BACKGROUND: Parenteral nutrition (PN) is available as individualized prescriptions frequently prepared with an automated compounding device or as commercially prepared premixed solutions. Our institution exclusively used individualized PN until an amino acid shortage forced a temporary switch to premixed solutions. In general, premixed solutions contain lower electrolyte levels than individualized formulations prescribed for patients with normal organ function. We aimed to quantify supplemental intravenous piggyback (IVPB) electrolyte use in adult patients receiving individualized and premixed PN and to quantify any effect on difference in the cost of therapy. METHODS: We compared use of supplemental IVPB electrolytes administered to patients receiving PN during consecutive periods prior to and during the amino acid shortage. Electrolyte IVPBs tabulated were potassium chloride, 10 and 20 mEq; magnesium sulfate, 2 g and 4 g; potassium phosphate, 7.5 and 15 mmol; and sodium phosphate, 7.5 and 15 mmol IVPB. RESULTS: There was no statistical difference in the number of PN formulations administered per day during each period (14.7 ± 3.9 vs 14.0 ± 2.6, individualized vs premixed, respectively). Total IVPB electrolytes prescribed per day increased significantly from the individualized PN period to the premixed PN period (7.03 ± 3.8 vs 13.8 ± 6.8; P < .0001). The additional IVPB electrolyte supplementation required in patients receiving premixed PN was associated with an additional $11,855.74 cost per 30 days of therapy compared with those who received individualized PN. CONCLUSION: Inpatient use of premixed PN results in a significant increase in IVPB electrolyte supplementation and cost compared with individualized PN use.