Functional metagenomics reveals differential chitin degradation and utilization features across free-living and host-associated marine microbiomes

BACKGROUND

Chitin ranks as the most abundant polysaccharide in the oceans yet knowledge of shifts in structure and diversity of chitin-degrading communities across marine niches is scarce. Here, we integrate cultivation-dependent and -independent approaches to shed light on the chitin processing potential within the microbiomes of marine sponges, octocorals, sediments, and seawater.

RESULTS

We found that cultivatable host-associated bacteria in the genera Aquimarina, Enterovibrio, Microbulbifer, Pseudoalteromonas, Shewanella, and Vibrio were able to degrade colloidal chitin in vitro. Congruent with enzymatic activity bioassays, genome-wide inspection of cultivated symbionts revealed that Vibrio and Aquimarina species, particularly, possess several endo- and exo-chitinase-encoding genes underlying their ability to cleave the large chitin polymer into oligomers and dimers. Conversely, Alphaproteobacteria species were found to specialize in the utilization of the chitin monomer N-acetylglucosamine more often. Phylogenetic assessments uncovered a high degree of within-genome diversification of multiple, full-length endo-chitinase genes for Aquimarina and Vibrio strains, suggestive of a versatile chitin catabolism aptitude. We then analyzed the abundance distributions of chitin metabolism-related genes across 30 Illumina-sequenced microbial metagenomes and found that the endosymbiotic consortium of Spongia officinalis is enriched in polysaccharide deacetylases, suggesting the ability of the marine sponge microbiome to convert chitin into its deacetylated-and biotechnologically versatile-form chitosan. Instead, the abundance of endo-chitinase and chitin-binding protein-encoding genes in healthy octocorals leveled up with those from the surrounding environment but was found to be depleted in necrotic octocoral tissue. Using cultivation-independent, taxonomic assignments of endo-chitinase encoding genes, we unveiled previously unsuspected richness and divergent structures of chitinolytic communities across host-associated and free-living biotopes, revealing putative roles for uncultivated Gammaproteobacteria and Chloroflexi symbionts in chitin processing within sessile marine invertebrates.

CONCLUSIONS

Our findings suggest that differential chitin degradation pathways, utilization, and turnover dictate the processing of chitin across marine micro-niches and support the hypothesis that inter-species cross-feeding could facilitate the co-existence of chitin utilizers within marine invertebrate microbiomes. We further identified chitin metabolism functions which may serve as indicators of microbiome integrity/dysbiosis in corals and reveal putative novel chitinolytic enzymes in the genus Aquimarina that may find applications in the blue biotechnology sector. Video abstract.

End-of-life issues

A patient's desire to discuss end-of-life (EOL) choices may be among the most stressful situations for clinicians. Research confirms the importance of discussions between caregivers and patients or their surrogates about options for current and future care. Often, terminally ill patients want to discuss EOL options to avoid undue suffering, pain, and other symptoms and want some reassurance that caregivers can provide effective physical, psychosocial, and spiritual care. Patients often approach nurses first and ask for their assistance before they ask other professionals; they are more likely to ask nurses in home care than in other settings.

Treating attention deficit hyperactivity disorder

Attention deficit hyperactivity disorder (ADHD) is a chronic childhood disorder characterized by inattention, distractibility, impulsivity, and restlessness. ADHD symptoms impair the child's ability to function at home, in school, and in the community. When ADHD is untreated, the child is at increased risk for school failure, substance abuse, and psychiatric disorders. New clinical practice guidelines from the American Academy of Pediatrics specify diagnosis and treatment for childhood ADHD, including psychosocial interventions, psychopharmacology, educational modifications, skill training, and social support.

Evaluating and managing intimate partner violence

An estimated 18% to 25% of female primary care and prenatal patients suffer from intimate partner violence, and 31% to 44% of women report some abuse during their lifetimes. Violence is often unreported because women fear the batterer's reprisals, time-consuming court procedures, shame, blame, and unreliable legal sanctions. Screening for domestic violence should be a routine aspect of health care. Clinicians must ask direct questions about violence and detect subtle and overt clues. This article presents the historical context of violence and examines screening, evaluation, treatment, and ethics.

Understanding oncology nurses' difficulties caring for suicidal people

Clinical challenges occur when patients consider suicide. Despite improved treatment, people with cancer have an increased risk of suicide. While previous research examined patients' perspectives, this study describes the nurse's perspective of difficulty of caring for suicidal patients. Suicidal ideas constitute common psychiatric complications of cancer, however we know little of the nurse's difficulties in care giving. As part of a larger study of oncology nurses' knowledge, we randomly surveyed 1,200 clinical oncology nurses and 434 returned completed questionnaires (37%). This paper describes content analysis of oncology nurses' narratives about their difficulties responding to suicidal patients. Six categories emerged: religious/other values, uncomfortable feelings, inadequate knowledge, personal experiences, and weight of professional responsibility which made it difficult for most nurses to care for suicidal patients. Some nurses reported they had no difficulties. Care giving is also difficult because the patient's right to choose suicide may conflict with the nurse's professional obligation to prevent suicide.

Pediatric epilepsy: primary care treatment and health care management

Childhood seizures are encountered frequently in the primary care setting. Seizures can cause considerable embarrassment and discomfort--as well as dangerous consequences--if not properly treated. Accurate diagnosis often depends on history and a parent's or teacher's clear and reliable description of the seizure. About two-thirds of properly treated patients achieve seizure remission within 10 years of diagnosis. In this article, the authors review standards of treatment and present the latest findings on the treatment of epilepsy. The goal of pharmacologic treatment is to reduce the frequency of seizures with few adverse effects. Because all antiepileptic drugs affect cognition to same degree, diminishing the potential cognitive and psychosocial effects of epilepsy is also a treatment goal. Commonly used and new antiepileptic drugs are discussed. Patient education is an important part of care and requires discussion of beliefs about epilepsy, lifestyle, self-esteem, and resources.

Rational suicide among patients who are terminally ill

Patients' end-of-life decisions challenge nurses. Often, aggressive, life prolonging strategies create ethical dilemmas for nurses when patients decide to stop treatment. In Oregon, assisted suicide is legal and will have a profound effect on nursing practice. When a patient considers suicide, nurses need to examine the patient's mental health, symptom management, and rational decision-making ability. Evaluation of suicide risk is a priority. Nurses need to recognize that medical land psychological symptoms often trigger thoughts of suicide, but prompt treatment of pain and symptoms also reduces suicide risk. Ethical issues and guidelines for management of patients considering suicide and evaluation of rationality are presented.

Diagnosis and treatment of major depression among people with cancer

Although depressive disorders are common among 20-25% of people with cancer, they are frequently unrecognized. Untreated depression in the presence of comorbid conditions may result in more frequent clinic visits, increased costs, extended hospitalization, and reduced compliance and quality-of-life. Oncology clinicians need not have psychiatric expertise to play a major role in the detection and treatment of depression and in the prevention of suicide. Using early detection and screening tools, the nurse can identify depressed patients and can collaborate in their treatment. Approximately 80-90% of depressed patients are effectively treated with psychotherapy, and/or pharmacologic, or somatic, interventions. Failure to diagnose or reluctance to treat depression among patients with cancer is a common error and can increase morbidity and mortality.

Exploring a life history of HIV disease and self-caring: Alfredo's story

Alfredo's story is part of a larger phenomenological study of nursing, self care, and HIV disease that incorporated the anthropological tradition of reconstructing a life-story in the person's own words. This exemplar emphasizes Alfredo's shifts perspective organized around three turnings, or shifts in perspective, which are illustrated with narrative text and discussed. The three turnings include becoming HIV-infected, becoming a positive force, and reclaiming self. Implications for nursing include the importance of story telling in life history, the value of knowing the patient as a person, the positive impact of negative events, and the educational impact of a paradigm case.

Managing depression among people with HIV disease

Many people with HIV suffer from depression, which responds to antidepressants, counseling, education, and cognitive strategies. Untreated depression hinders treatment compliance and increases risk of suicide. Management and complications of major depression are described. The evaluation of rational suicide is examined. Clinicians who treat this population need to respond therapeutically to patients with depression and suicidal ideas.

Diagnosis and treatment of panic disorder and generalized anxiety in primary care

Anxiety is one of the common yet underdiagnosed mental health problems of Americans; as many as 20% of people seeking primary care have symptoms of treatable anxiety disorders. Untreated anxiety increases costly visits to urgent care. Clinicians need to screen for anxiety among patients at risk who have physical symptoms such as shortness of breath, nervousness, gastrointestinal upset, palpitations, muscle aches, tension, and insomnia. Other diagnostic clues include restlessness, nervousness, phobias, trembling, fatigue, and shaking. Onset typically occurs in the 20s but may occur at any age. Symptoms of two anxiety disorders, generalized anxiety disorder (GAD) and panic disorder, are discussed. A combination of treatments including antidepressant and anxiolytic medications, behavioral treatments, education (e.g., self-management, relaxation), and counseling (e.g., coping strategies) have high success rates; psychiatric consultations or referrals are useful.

Management of suicidal patients with HIV disease

Suicidal acts among people with HIV disease exceed those among the general population. Stress from the HIV diagnosis, treatment, and medications can lead to depression, which increases suicide risk. High quality care of depressed persons depends on sound scientific knowledge of evaluation of suicide. Incidence, epidemiology, risk factors, evaluation, and treatment of suicidal people are the core of this article. A patient's comment, "I'd be better off dead," deserves investigation as a cry for help and a clue to impending suicide.

Messages of psychiatric patients who attempted or committed suicide

The stigma attached to suicide, and a qualitative analysis of psychiatric patients' suicide messages that emerged from a study of psychological characteristics and communications of suicidal psychiatric patients, are described. In this retrospective study, the suicide messages from clinical records of 25 suicide completers and a matched cohort of suicide attempters from a Veterans Affairs Medical Center were analyzed. A qualitative method developed by Leenaars in 1992 was used to examine themes in suicide messages. Analysis indicated that clear suicidal messages are sent by most psychiatric patients, and that some useful distinctions exist between messages of completers and attempters. Suicide messages offer worthwhile indicators of suicide that assist clinicians in their therapeutic and preventive roles. The themes of the psychiatric patients' suicide messages included unbearable psychological pain, interpersonal relations, and aggression-rejection. The present study enhances clinicians' recognition of themes in suicide messages and improves the estimation of suicide risk among psychiatric patients.

Psychotherapist reactions to the suicide of a patient

A patient's suicide may evoke the therapist's personal grief and influence professional competence or suicide prevention skills. The incidence of suicide by patients in therapy is examined and empirical studies of therapist response--which commonly includes grief, guilt, self-blame, anger, fear, and self-doubt--are reviewed. Bereavement theories and support programs are described.

Nurses' grief

Bereavement, a well-established threat to health and work performance, is one of the most universal human responses that nurses experience. Because patient death is frequent, oncology nurses commonly experience bereavement; they may identify with the family, feel sad at the death, or feel awkward in responding to a death. After patients die, nurses manage bereavement tasks such as making sense of the death, managing mild to intense emotions, and realigning relationships. These tasks become more difficult when multiple deaths are encountered or when a conflict about the death occurs. Understanding theories, models, tasks, and factors influencing their bereavement may help nurses to facilitate their own grief and to reduce bereavement overload. The purpose of this article is to review knowledge and factors that influence nurses' bereavement and offer guidelines for managing grief. Information for this article was derived from several sources: (a) a review of existing literature; (b) clinical experience; and (c) analysis of personal inventories from over 300 nurses attending the authors' bereavement workshops.

Oncology nurses' knowledge and misconceptions about suicide

Nurses' knowledge of suicide has been underinvestigated. This article summarizes a survey of oncology nurses' knowledge and misconceptions about suicide. Nurses' knowledge of risk factors, suicide potential, and management of a suicidal patient were examined after nurses read a vignette about a suicidal patient with cancer. Analysis included descriptive statistics and content analysis. Approximately 20% of nurses underestimated the patient's suicide risk. Nurses correctly identified an average of three of eight risk factors, but 61% misidentified worries and fears as suicide risk factors or indicators of suicide risk. More than 60% of nurses correctly identified saying goodbye, giving away a treasured object, being a widower, and wishing to be dead as risk factors. Few knew that race/ethnicity (3.23%), male gender (23.66%), and age (31.18%) were risk factors. Undiagnosed mental disorders also increase suicide risk. Physicians and nurses often fail to ask oncology patients about depression, and depressed patients often report only physical symptoms and minimize their depression or suicidal ideas. Before committing suicide, 8 of 10 suicidal people had asked for better management of their physical symptoms, but their suicide risk was not detected. After recognizing any indicator of suicide risk, a nurse should assess risk factors, detect clues, and estimate individual lethality. Few (15.12%) nurses asked about a suicide plan as a nursing assessment, and 37% of the nurses used consultation. Less than one-third of nurses recommended providing safety, protecting the patient, or taking suicide precautions. Such evidence indicates the need for education to enhance knowledge and skill building to improve the interviewing and care of suicidal patients.

Evaluating depression among patients with cancer

The stress, diagnosis, and treatment of cancer cause substantial psychiatric morbidity that is treatable. Chemotherapy or other cancer treatments cause 40% to 60% of patients' emotional distress. Major depression develops in approximately 25% of patients with cancer, and less severe depressive symptoms develop in many patients, but fewer than half of the patients with symptoms are offered treatment. Alleviating major depression improves the quality of life for these patients with cancer. These patients, particularly during terminal illness, have an increased risk of suicide. Clinicians proficient in psychosocial assessment can detect subtle signs, monitor risk factors, reduce major depression with cognitive strategies, and prevent complications. Untreated major depression lowers life expectancy and treatment compliance and increases risk of suicide and cardiac disease. In this article, incidence of major depression among patients with cancer is discussed. Guidelines for diagnosis, correcting myths, and detecting major depression are suggested. Effective cognitive strategies for intervention are described; medical treatment is briefly reviewed. Detection and evaluation of suicide risk are discussed.

Self-care, psychological distress, and HIV disease

Self-care behaviors may be positive (healthy) or negative (unhealthy). Many factors may influence whether individuals choose healthy or unhealthy self-care behaviors. This study examined the relationships of perceived impact of HIV status, distress, and subsequent changes in self-care activities among men and women who were at risk for or infected with HIV. Significant findings included a positive correlation between the number of symptoms experienced and both depression and change toward unhealthy self-care behaviors. The impact of event avoidance and depression were associated with changes to unhealthy self-care behaviors, although hopelessness was associated with fewer unhealthy changes.

Evaluating suicide risk in the medically ill patient

Common medical conditions, treatments, medications, and depression can increase the risk of suicide, which is the eighth leading cause of death in the United States. Health care providers are in key positions to prevent suicide because most people seek medical treatment for physical symptoms and they give clues before they commit suicide. Unfortunately, suicide risk typically remains undetected because suicide clues, including depression, are overlooked. This article reviews assessment of suicide risk, incidence of completed suicide, and interventions in primary care settings. Suicide lethality, therapeutic strategies, and referrals are considered. Depression is discussed because it is the most common precipitant of suicide in primary care.

The challenge of ritualistic child abuse

Survivors of ritual abuse have endured physical and psychosexual trauma typically compounded by mind-altering drugs. Some abused children have never known a trustworthy adult to protect them from harm. Children often cope with the anxiety and terror of abuse through psychological defenses such as denial, self-hypnosis, and dissociation, but more extreme responses such as self-mutilation or multiple personalities may occur. Reports of ritual abuse of children are so shocking and bizarre that professionals initially respond with confusion and disbelief (Cozolino, 1989). Nurses need to assess clues and detect symbols of abuse in drawings or flashbacks, to build trust, and to monitor their attitudes and countertransference. Nurses are in a critical position to detect and begin healing wounds of ritual abuse.

Deliberate Self-Injury: Management in a Psychiatric Setting

Self-injury is a significant clinical problem of psychiatric patients, although the prevalence of self-injury in specific disorders is unclear. Nurses can assess and intervene in the psychological causes and behavioral sequelae self-injury. Each patient's early history, dynamics, and motives for self-injury require evaluation. Behavioral techniques (eg, reinforcement) and psychodynamic techniques, such as exploring feelings and anxiety, can help patients understand their self-destructive tendencies. Patients can learn to anticipate anxiety-provoking situations, plan strategies to manage anxiety, cope with feelings, and reduce self-injury.

Electroconvulsive therapy

Electroconvulsive therapy treatment for severely depressed adults is increasing because it economically and rapidly reduces symptoms in most patients. Improved administration and unilateral electrode placement have decreased complications. However, concern exists about cognitive and other adverse effects of electroconvulsive therapy. Nurses are in a critical position to educate patients about electroconvulsive therapy, to be advocates for patients' rights, and to monitor responses to treatment. Because both depression and electroconvulsive therapy may impair cognitive functioning, nurses should renegotiate patients' consent during electroconvulsive therapy. Nurses who know, research, and evaluate memory and confusion can effectively observe and diminish the side effects of electroconvulsive therapy.

Using hypnosis with children for pain management

Although nurses are in a strategic position to use hypnosis to manage a child's cancer pain, many lack the knowledge, the skill, or the exposure to the clinical effectiveness of hypnosis. Hypnosis has been a potent analgesic and anesthetic agent for more than 100 years; it reduces a child's cancer pain and the pain associated with painful procedures. Nurses can use hypnosis to help children diminish pain and cope with lumbar punctures (LPs), bone marrow aspirations (BMAs), and nausea or vomiting from chemotherapy. This article's purpose is to discuss myths, contraindications, research, processes, and effectiveness of hypnosis as a strategy for managing the cancer pain of school-age children. Vignettes from the author's clinical practice illustrate concepts and procedures.

Clinical hypnosis with school-age children

Despite the fact that nurses are in key positions to learn and use hypnosis to bolster a child's symptom management, ability to solve problems, or self-esteem, they lack knowledge about the clinical effectiveness of hypnosis. Substantial clinical literature demonstrates that hypnosis effectively reduces anxiety, enhances coping, and has been used successfully to treat behavior disorders, school phobias, and sleep disorders. Hypnosis can effectively reduce a child's anxiety and symptoms and has few side effects when used competently. With education and supervision, nurses can effectively use hypnosis to improve a child's mastery and self-esteem and to reduce severe levels of anxiety.

Adolescent suicide: assessment and intervention

Understanding how to prevent suicide, the third leading cause of adolescent death, is the focus of this article. To prevent suicide, the nurse assesses risk factors, covert messages, overt suicide clues, and intervenes with the adolescent and family. Suicide risk and hopelessness decrease as suicidal youths learn to clarify problems, rally significant others, expand resources and use safe coping strategies. Interventions include a no-suicide contract, family therapy and school suicide prevention programs. Nurses can identify the youth at risk for suicide and, in many cases, provide the therapy that helps prevent suicide. Vignettes illustrate strategies that effectively reduce suicide risk.