Indomethacin and 20-hydroxyecdysone influence protein expression in a Spodoptera frugiperda nervous system cell line.

Insecticide mode of action studies provide insights into how new insecticidal actives function and contribute to assessing safety to humans and nontarget organisms. Insect cell lines that express potential target sites can serve as valuable tools in this effort. In this paper, we report on the influence of two signaling molecules on protein expression in a nervous system cell line established from Spodoptera frugiperda (Bayer/BCIRL-SfNS2-0714-TR). We selected this line because we established it in our laboratory and we are experienced in using it. Cells were exposed to the insect developmental hormone (1 µg/mL 20-hydroxyecdysone, 20E) and/or a cyclooxygenase (COX) inhibitor (25 µM indomethacin, INDO; inhibits prostaglandin [PG] biosynthesis) for 24 h (Day 2), 72 h (Day 4), or 120 h (Day 6). We selected a PG biosynthesis inhibitor because PGs act in many aspects of insect biology, such as embryonic development, immunity, and protein phosphorylation. We selected the developmental hormone, 20E, because it also acts in fundamental aspects of insect biology. We identified specific proteins via in silico analysis. Changes in protein expression levels were determined using liquid chromatography-mass spectrometry (MS) + MS-MS. The largest number of changes in protein expression occurred on Day 2. The combination of 20E plus INDO led to 222 differentially expressed proteins, which documents the deep significance of PGs and 20E in insect biology. 20E and, separately, INDO led to changes in 30 proteins each (p value < 0.01; >2X or <0.5X-fold changes). We recorded changes in the expression of 9 or 12 proteins (20E), 10 or 6 proteins (INDO), and 21 or 20 proteins (20E + INDO) on D4 and D6, respectively. While the cell line was established from neuronal tissue, the differentially expressed proteins act in a variety of fundamental cell processes. In this paper, we moved beyond a list of proteins by providing detailed, Gene Ontology term analyses and enrichment, which offers an in-depth understanding of the influence of these treatments on the SfNS2 cells. Because proteins are active components of cell physiology in their roles as enzymes, receptors, elements of signaling transduction pathways, and cellular structures, changes in their expression levels under the influence of signaling molecules provide insights into their function in insect cell physiology.

A content analysis of counseling psychology literature: Resilience against oppression among people of color.

The researchers analyzed articles from two flagship counseling psychology journals (i.e., Journal of Counseling Psychology and The Counseling Psychologist) to examine current understandings of resilience. There were 54 articles included in the final analysis that spanned the years 1997-2022. The researchers conducted a content analysis to identify, analyze, and report patterns across counseling psychology journals with regard to how resilience has been defined, the racial/ethnic groups that were of focus, and the forms of oppression that were studied or addressed. Five themes were generated that are a direct representation of the topics within previous literature on resilience in the field of counseling psychology. Those topics included: (a) ways of coping, (b) ethnic and racial identity, (c) advocacy/collective action, (d) personality factors, and (e) ability to endure stress and thrive. Implications for future research, clinical applications, mentoring, and advocacy are discussed. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Why can insects not biosynthesize cholesterol?

Two aspects of insect lipid biochemistry differ from the mammalian background. In one aspect, nearly a hundred years ago scientists demonstrated that the polyunsaturated fatty acid (PUFAs), linoleic acid (LA; 18:2n-6) is an essential nutrient in the diets of all mammals that have been studied in that regard. An unknown number of insect species are able to biosynthesize LA de novo. Some species take the biosynthesized LA into fatty acid elongation/desaturation pathways to produce other PUFAs, 18:3n-6, 20:3n-6 and 20:4n-6. A couple of species use the de novo produced LA to biosynthesize prostaglandins and other eicosanoids, short-lived signal moieties that mediate important physiological actions in immunity and reproduction. Insects differ from mammals, also, in their lack of genes that encode enzymes acting in biosynthesis of cholesterol. Insects require dietary cholesterol to meet their cellular, physiological, developmental, and reproductive needs. Looking at a broader view of invertebrate biochemistry, most protostomes lost all or most genes involved in cholesterol biosynthesis. The massive gene loss occurred during the Ediacaran Period, which lasted 96 million years, from the end of the Cryogenian Period (635 million years ago; MYA) to the beginning of the Cambrian Period (538.6 MYA). The key point here is that the inability to biosynthesize cholesterol is not limited to insects; it occured in most protostomes. We address the protostome need and benefits of acquiring exogenous sterols.

What is in a model?

After reading contradictory claims of model status for some insect species, we feel a brief discussion of the topic may be useful. Here, we document a few examples where clarity on model status seems to be lacking, briefly review work on widely recognized models, and offer criteria for including any given species as a model organism.

Differential contributions of synaptic and intrinsic inhibitory currents to speech segmentation via flexible phase-locking in neural oscillators.

Current hypotheses suggest that speech segmentation-the initial division and grouping of the speech stream into candidate phrases, syllables, and phonemes for further linguistic processing-is executed by a hierarchy of oscillators in auditory cortex. Theta (∼3-12 Hz) rhythms play a key role by phase-locking to recurring acoustic features marking syllable boundaries. Reliable synchronization to quasi-rhythmic inputs, whose variable frequency can dip below cortical theta frequencies (down to ∼1 Hz), requires "flexible" theta oscillators whose underlying neuronal mechanisms remain unknown. Using biophysical computational models, we found that the flexibility of phase-locking in neural oscillators depended on the types of hyperpolarizing currents that paced them. Simulated cortical theta oscillators flexibly phase-locked to slow inputs when these inputs caused both (i) spiking and (ii) the subsequent buildup of outward current sufficient to delay further spiking until the next input. The greatest flexibility in phase-locking arose from a synergistic interaction between intrinsic currents that was not replicated by synaptic currents at similar timescales. Flexibility in phase-locking enabled improved entrainment to speech input, optimal at mid-vocalic channels, which in turn supported syllabic-timescale segmentation through identification of vocalic nuclei. Our results suggest that synaptic and intrinsic inhibition contribute to frequency-restricted and -flexible phase-locking in neural oscillators, respectively. Their differential deployment may enable neural oscillators to play diverse roles, from reliable internal clocking to adaptive segmentation of quasi-regular sensory inputs like speech.

Identification and expression profiling of serine protease-related genes in Tenebrio molitor.

In insects, serine proteases and serine protease homologs (SPs/SPHs) are involved in a variety of physiological processes including digestion, development, and immunity. Here, we identified 112 SP and 88 SPH genes in the genome of the yellow mealworm, Tenebrio molitor. Based on the features of domain structure, they were divided into "S" group containing single Tryp-SPc or Tryp-SPHc domain, "C" group containing 1-4 CLIP domain (CLIPA-D) and "M" group containing the CBD, CUB, EGF, Fz, Gd, LDLa, PAN, SEA, SR, Sushi, and TSP domains, and have 115, 48, and 37 gene members, respectively. According to the active sites in the catalytic triad, the putative trypsin, chymotrypsin, or elastase-like enzyme specificity of the identified SPs/SPHs were predicted. Phylogenetic and genomic location analyses revealed that gene duplication exists in the large amount of SPs/SPHs. Gene expression profiling using RNA-seq data along with real time reverse transcription-polymerase chain reaction analysis showed that most SP/SPH genes display life stage specific expression patterns, indicating their important roles in development. Many SP/SPH genes are specifically or highly expressed in the gut, salivary gland, fat body, hemocyte, ovary, and testis, suggesting that they participate in digestion, immunity, and reproduction. The findings lay the foundation for further functional characterization of SPs/SPHs in T. molitor.

Comparative genomic analysis of carboxylesterase genes in Tenebrio molitor and other four tenebrionids.

Carboxylesterases (COEs) have various functions in wide taxons of organisms. In insects, COEs are important enzymes involved in the hydrolysis of a variety of ester-containing xenobiotics, neural signal transmission, pheromone degradation, and reproductive development. Understanding the diversity of COEs is basic to illustrate their functions. In this study, we identified 53, 105, 37, and 39 COEs from the genomes of Tenebrio molitor, Asbolus verucosus, Hycleus cichorii, and H. phaleratus in the superfamily of Tenebrionidea, respectively. Phylogenetic analysis showed that 234 COEs from these four species and those reported in Tribolium castaneum (63) could be divided into 12 clades and three major classes. The α-esterases significantly expanded in T. molitor, A. verucosus, and T. castaneum compared to dipteran and hymenopteran insects. In T. molitor, most COEs showed tissue and stage-specific but not a sex-biased expression. Our results provide insights into the diversity and evolutionary characteristics of COEs in tenebrionids, and lay a foundation for the functional characterization of COEs in the yellow mealworm.

Genome-wide and expression-profiling analyses of the cytochrome P450 genes in Tenebrionidea.

Cytochrome P450 monooxygenases (CYPs) are present in almost all areas of the tree of life. As one of the largest and most diverse superfamilies of multifunctional enzymes, they play important roles in the metabolism of xenobiotics and biosynthesis of endogenous compounds, shaping the success of insects. In this study, the CYPome (an omics term for all the CYP genes in a genome) diversification was examined in the four Tenebrionidea species through genome-wide analysis. A total of 483 CYP genes were identified, of which 103, 157, 122, and 101 were respectively deciphered from the genomes of Tebebrio molitor, Asbolus verucosus, Hycleus cichorii and Hycleus phaleratus. These CYPs were classified into four major clans (mitochondrial, CYP2, CYP3, and CYP4), and clans CYP3 and CYP4 are most diverse. Phylogenetic analysis showed that most CYPs of these Tenebrionidea beetles from each clan had a very close 1:1 orthology to each other, suggesting that they originate closely and have evolutionally conserved function. Expression analysis at different developmental stages and in various tissues showed the life stage-, gut-, salivary gland-, fat body-, Malpighian tubule-, antennae-, ovary- and testis-specific expression patterns of T. molitor CYP genes, implying their various potential roles in development, detoxification, immune response, digestion, olfaction, and reproduction. Our studies provide a platform to understand the evolution of Tenebrionidea CYP gene superfamily, and a basis for further functional investigation of the T. molitor CYPs involved in various biological processes.

Characterization and expression profiling of serine protease inhibitors in the yellow mealworm Tenebrio molitor.

Serine protease inhibitors (SPIs) act in diverse biological processes in insects such as immunity, development, and digestion by preventing the unwanted proteolysis. So far, the repertoire of genes encoding SPIs has been identified from few insect species. In this study, 62 SPI genes were identified from the genome of the yellow mealworm, Tenebrio molitor. According to their modes of action, they were classified into three families, serpin (26), canonical SPI (31), and α-macroglobulins (A2M) (5). These SPIs feature eight domains including serpin, Kazal, TIL, Kunitz, WAP, Antistasin, pacifastin, and A2M. In total, 39 SPIs contain a single SPI domain, while the others encode at least two inhibitor units. Based on the amino acids in the cleaved reactive sites, the abilities of these SPIs to inhibit trypsin, chymotrypsin, or elastase-like enzymes are predicted. The expression profiling based on the RNA-seq data showed that these genes displayed stage-specific expression patterns during development, suggesting to us their significance in development. Some of the SPI genes were exclusively expressed in particular tissues such as hemocyte, fat body, gut, ovary, and testis, which may be involved in biological processes specific to the indicated tissues. These findings provide necessary information for further investigation of insect SPIs.

Genomic and transcriptomic analyses of chitin metabolism enzymes in Tenebrio molitor.

Chitin is of great importance in the cuticle and inner cuticular linings of insects. Chitin synthases (CHSs), chitin deacetylases (CDAs), chitinases (CHTs), and ß-N-acetylhexosaminidases (HEXs) are important enzymes required for chitin metabolism, and play essential roles in development and metamorphosis. Although chitin metabolism genes have been well characterized in limited insects, the information in the yellow mealworm, Tenebrio molitor, a model insect, is presently still unavailable. With the help of bioinformatics, we identified 54 genes that encode putative chitin metabolism enzymes, including 2 CHSs, 10 CDAs, 32 CHTs, and 10 HEXs in the genome of T. molitor. All these genes have the conserved domains and motifs of their corresponding protein family. Phylogenetic analyses indicated that CHS genes were divided into two groups. CDA genes were clustered into five groups. CHT genes were phylogenetically grouped into 11 clades, among which 1 in the endo-ß-N-acetylglucosaminidases group and the others were classified in the glycoside hydrolase family 18 groups. HEX genes were assorted into six groups. Developmental and tissue-specific expression profiling indicated that the identified chitin metabolism genes showed dynamical expression patterns concurrent with specific instar during molting period, suggesting their significant roles in molting and development. They were predominantly expressed in different tissues or body parts, implying their functional specialization and diversity. The results provide important information for further clarifying their biological functions using the yellow mealworm as an ideal experimental insect.

Comparative genomic analysis of ABC transporter genes in Tenebrio molitor and four other tenebrionid beetles (Coleoptera: Tenebrionidea).

ATP-binding cassette (ABC) transporters, one of the largest transmembrane protein families, transport a diverse number of substate across membranes. Details of their diverse physiological functions have not been established. Here, we identified 87 ABC transporter genes in the genomes of Tenebrio molitor along with those from Asbolus verrucosus (104), Hycleus cichorii (65), and Hycleus phaleratus (80). Combining these genes (336 in total) with genes reported in Tribolium castaneum (73), we analyzed the phylogeny of ABC transporter genes in all five Tenebrionids. They are assigned into eight subfamilies (ABCA-H). In comparison to other species, the ABCC subfamily in this group of beetles appears expanded. The expression profiles of the T. molitor genes at different life stages and in various tissues were also investigated using transcriptomic analysis. Most of them display developmental specific expression patterns, suggesting to us their possible roles in development. Most of them are highly expressed in detoxification-related tissues including gut and Malpighian tubule, from which we infer their roles in insecticide resistance. We detected specific or abundant expressions of many ABC transporter genes in various tissues such as salivary gland, ovary, testis, and antenna. This new information helps generate new hypotheses on their biological significance within tissues.

The Wnt gene family in Tenebrio molitor and other coleopterans.

The Wnt gene family is involved in a wide range of developmental processes. Despite its significance, the evolution and function of Wnt genes remain largely unclear. Here, an exhaustive survey of Wnt genes was conducted in Tenebrio molitor and 17 other beetle genomes. A total of 146 Wnt genes were identified, creating a comprehensive coleopteran Wnt gene catalog. Comparative genomics indicates that dynamic evolutionary patterns of Wnt gene loss and duplication occurred in Coleoptera, leading to the diverse Wnt gene repertoire in various beetles. A striking loss of particular Wnt gene subfamilies occurs in Coleoptera. Remarkably, Wnt gene duplication was discovered for the first time in insects. Further analysis of Wnt gene expression in T. molitor indicates that each Wnt gene, including the duplicated ones, has a unique spatial or temporal expression pattern. The current study provides valuable insight into the evolution and functional validation of Wnt genes in Coleoptera.

The TGF-ß Receptor Gene Saxophone Influences Larval-Pupal-Adult Development in Tribolium castaneum.

The transforming growth factor-ß (TGF-ß) superfamily encodes a large group of proteins, including TGF-ß isoforms, bone morphogenetic proteins and activins that act through conserved cell-surface receptors and signaling co-receptors. TGF-ß signaling in insects controls physiological events, including growth, development, diapause, caste determination and metamorphosis. In this study, we used the red flour beetle, Tribolium castaneum, as a model species to investigate the role of the type I TGF-ß receptor, saxophone (Sax), in mediating development. Developmental and tissue-specific expression profiles indicated Sax is constitutively expressed during development with lower expression in 19- and 20-day (6th instar) larvae. RNAi knockdown of Sax in 19-day larvae prolonged developmental duration from larvae to pupae and significantly decreased pupation and adult eclosion in a dose-dependent manner. At 50 ng dsSax/larva, Sax knockdown led to an 84.4% pupation rate and 46.3% adult emergence rate. At 100 ng and 200 ng dsSax/larva, pupation was down to 75.6% and 50%, respectively, with 0% adult emergence following treatments with both doses. These phenotypes were similar to those following knockdowns of 20-hydroxyecdysone (20E) receptor genes, ecdysone receptor (EcR) or ultraspiracle protein (USP). Expression of 20E biosynthesis genes disembodied and spookier, 20E receptor genes EcR and USP, and 20E downstream genes BrC and E75, were suppressed after the Sax knockdown. Topical application of 20E on larvae treated with dsSax partially rescued the dsSax-driven defects. We can infer that the TGF-ß receptor gene Sax influences larval-pupal-adult development via 20E signaling in T. castaneum.

Octopamine signaling is involved in the female postmating state in Nilaparvata lugens Stål (Hemiptera: Delphacidae).

Mating triggers physiological and behavioral changes in female insects. In many species, females experience postmating behavioral and physiological changes that define a post-mated state. These changes are comprised of several conditions, including long-term refractoriness to re-mating and increased production and laying of eggs. Here, we report that mating led to several changes in brown planthopper (BPH) females, including increased octopamine (OA), cAMP concentrations, and activities of several enzymes. Mating also led to changes in the expression of several genes acting in female physiology, including those in the cAMP/PKA signal transduction pathway. OA injections into virgin females led to similar changes. RNAi silencing of the gene encoding tyramine ß-hydroxylase, involved in the final step in OA synthesis, led to decreased expression of these genes, and reduced the cAMP/PKA signaling. At the whole-organism level, the RNAi treatments led to reduced fecundity, body weights, and longevity. RNAi silencing of genes acting in OA signaling led to truncated ovarian development, egg maturation, and ovarian vitellogenin (Vg) uptake. The impact of these decreases is also registered at the population level, seen as decreased population growth. We infer that OA signaling modulates the postmating state in female BPH and possibly other hemipterans.

Prostaglandin A2 induces apoptosis in three cell lines derived from the fall armyworm, Spodoptera frugiperda.

Animals maintain homeostasis of cell numbers, constantly creating new cells and eliminating others. Programmed cell death, apoptosis, is a mechanism of cell elimination and it acts in many aspects of animal biology. Drawing on the biomedical background, several signals launch the apoptosis mechanisms, including prostaglandins (PGs). Based on this information, we posed the hypothesis that PGs similarly induce apoptosis in insect cell lines. We used three Spodoptera frugiperda cell lines, including two newly established, BCIRL-SfNS-0518B-YL derived from the central nervous system and BCIRL-Sf4FB-0614-SGS derived from fat body, and the commercially available Sf9 cells. Using a kinetic apoptosis kit, we found treating SfNS cells for 18 h with 15 or 20 µM PGA2 led to decreases in cell numbers, coupled with increased numbers of apoptotic and dead cells. Similar exposures to 10 µM PGA2 (24 h) led to substantial increases in apoptotic cells, confirmed by a terminal deoxynucleotidyl transferase dUTP nick end labeling assay on a flow cytometer. The influence of PGA2 treatments increased with dosage, as we recorded about 20% apoptosis at 24 h post-PGA2 treatments (10 µM) and about 34% apoptosis at 24 h post-30 µM treatments. PGA2 treatments led to 10- to 30-fold increases in messenger RNAs (mRNAs) encoding apoptosis-specific caspases-1, -2, -3, and -5 at 12 h and 40- to 60-fold increases in mRNAs encoding caspases-1 and -2, 10-fold increases for caspases-3 and -5 at 24 h. These findings strongly support our hypothesis that PGs induce apoptosis in an insect cell line and confirm an additional PG action in insect biology.

Silencing of a putative alanine aminotransferase (ALT) gene influences free amino acid composition in hemolymph and fecundity of the predatory bug, Cyrtorhinus lividipennis Reuter.

In Asian rice systems, Cyrtorhinus lividipennis Reuter is an important predator that preys on rice planthopper eggs and young nymphs, as a primary food source. Alanine aminotransferase (ALT) acts in many physiological and biochemical processes in insects. We cloned the full-length complementary DNA of C. lividipennis ClALT. Expression analysis showed higher expression in the fat body and midgut compared to other tissues. It is expressed in all C. lividipennis developmental stages and at least four organs. Silencing of ClALT by RNA interference significantly decreased the ClALT enzyme activity and ClALT expression compared to dsGFP-treated controls at 2 days after emergence (DAE). Silencing of ClALT influenced free hemolymph amino acid compositions, resulting in a reduction of Aspartic acid (Asp) and Alanine (Ala) proportions, and increased Cysteine (Cys) and Valine (Val) proportions in females at 2 DAE. dsClALT treatments led to decreased soluble total protein concentrations in ovary and fat body, and to lower reduced vitellogenin (Vg) expression, body weight, and the numbers of laid eggs. The double-stranded RNA viruse treatments also led to prolonged preoviposition periods and hindered ovarian development. Western blot analysis indicated that silencing ClALT also led to reduced fat body Vg protein abundance at 2 DAE. These data support our hypothesis that ClALT influences amino acid metabolism and fecundity in C. lividipennis.

Outcomes following revision of the revision total elbow arthroplasty.

BACKGROUND: There is very little information in the literature on the outcomes of revision of revision total elbow arthroplasty (RRTEA). Our aim was to report the outcomes of this rarely performed procedure. METHODS: We retrospectively identified all patients who had undergone RRTEA between 2007 and 2016. Outcomes were assessed clinically using a number of validated systems, and radiographs were reviewed for prosthesis alignment, cementation by Morrey grading, and heterotopic ossification. RESULTS: We identified 22 patients who underwent RRTEA. Of these patients, 14 were available for assessment (2 died of unrelated causes, 2 could not be contacted, 2 declined to participate because of travel difficulties, and 2 had incomplete data). At the final review, the median age was 73 years (range, 57-83 years), with a median follow-up period of 4.5 years (range, 2-7 years) since the last surgical procedure. The median number of previous revision arthroplasty procedures per patient was 3 (range, 2-6). The indications for RRTEA were aseptic loosening (60%), bushing wear (16%), fracture (14%), and infection (10%). Of the patients, 30% required extra-long or custom-made implants and 50% needed allograft augmentation. At final clinical assessment, 56% of patients had triceps insufficiency, the median flexion-extension arc was 90°, and the median prono-supination arc was 95°. The functional elbow scores revealed good outcomes in the majority of patients (median visual analog scale score, 5; median Oxford Elbow Score, 22; median Mayo Elbow Performance Index score, 55; and median QuickDASH [short version of Disabilities of the Arm, Shoulder and Hand questionnaire] score, 63). Eighty-one percent of patients were satisfied with their RRTEAs. Complications included infection in 2 patients (1 superficial and 1 deep), symptomatic aseptic humeral component loosening in 1, sensory ulnar nerve symptoms in 2, and radial nerve injury in 1. One patient required ulnar nerve release. Radiologic review revealed asymptomatic loosening in 1 patient (humeral component), and overall prosthesis alignment with cementation was adequate in 81%. Heterotopic ossification was present in 38% of cases. CONCLUSIONS: RRTEA is a satisfactory treatment option in these complex cases, with good short- to mid-term survival rates but a relatively high complication rate.

Revision total elbow arthroplasty: Is it safe to perform a single-stage revision for presumed aseptic loosening based on clinical assessment, normal inflammatory markers, and a negative aspiration?

BACKGROUND: Revision total elbow arthroplasty (TEA) is a challenging procedure that is becoming increasingly common. In our unit, we regard it as essential to exclude infection as the underlying cause of TEA loosening. In all patients with arthroplasty loosening, we undertake a careful history and examination, perform radiographs, monitor inflammatory markers, and undertake a joint aspiration. If any investigation suggests infection as the etiology, then a 2-stage revision is undertaken. Open biopsies are not routinely performed. The aim was to ascertain from our outcomes whether it is safe to perform a single-stage revision for presumed aseptic loosening using these criteria. METHODS: A retrospective review of a consecutive series of revision TEAs was performed in our unit over a 10-year period (2008-2018). Single-stage revisions performed for presumed aseptic loosening were identified. Case notes, radiographs, bloods, aspiration results, and microbiology of tissue samples taken at revision were reviewed. RESULTS: A total of 123 revision elbow arthroplasty cases were performed in the study period. Sixty cases were revised for preoperatively proven infection, instability, or implant failure and were excluded from this study. In 63 cases, aseptic loosening was diagnosed based on history, clinical examination, blood markers, and aspiration. There were 21 dual-component and 42 single-component revisions. In the dual-component revision group, tissue samples taken at the time of revision were positive in only 1 case (5%). In the single-component revision group, positive culture samples were present in 3 cases (7%). χ2 analysis showed no significant difference between single- and dual-component revisions (P = .76). No cases with positive culture samples from either group have required subsequent revision surgery. CONCLUSION: Given the results of this study, we conclude that is safe to perform single-stage revision arthroplasty for implant loosening based on history, examination, normal inflammatory markers, and negative aspiration results without the need for open biopsy.

Nursing and values-based leadership: A literature review.

AIM: To explore literature that supports an understanding of values-based leadership in nursing. BACKGROUND: Understanding values-based leadership in nursing means understanding several leadership theories such as authentic, servant and congruent leadership. EVALUATION: Electronic databases were systematically searched to locate studies with the terms values-based, authentic, servant and congruent leadership. The literature was assessed with the Joanna Briggs Institute Critical Appraisal Tools and the Preferred Reporting Items for Systematic Reviews and meta-analysis approach and a thematic analysis. KEY ISSUES: Existing evidence focuses on specific perspectives within three dominant leadership approaches under the umbrella of values-based leadership: authentic, servant and congruent leadership. Limited literature suggests that values-based leadership can support professional collaboration, enhanced trust and voice for nurses, support for staff well-being, empowerment, job satisfaction, patient-focused outcomes and quality care. CONCLUSIONS: A dearth of empirical literature concerning values-based leadership and nursing exists. Evidence suggests that authentic, servant and congruent leadership correlate with values-based leadership theories and core nursing values. IMPLICATIONS FOR NURSING MANAGEMENT: Nurse managers should recognize the potential benefits of a values-based leadership approach for staff well-being, enhanced professional collaboration and the nurses voice, improved insight into clinical leadership attributes and improvements in quality patient care.

Pesticide-Induced Planthopper Population Resurgence in Rice Cropping Systems.

Planthoppers are serious rice pests in Asia. Their population resurgence was first reported in the early 1960s, caused mainly by insecticides that indiscriminately killed beneficial arthropods and target pests. The subsequent resurgence involved two mechanisms, the loss of beneficial insects and insecticide-enhanced planthopper reproduction. In this review, we identify two forms of resurgence, acute and chronic. Acute resurgence is caused by traditional insecticides with rapid resurgence in the F1 generation. Chronic resurgence follows application of modern pesticides, including fungicides and herbicides, with low natural enemy toxicity, coupled with stimulated planthopper reproduction. The chemical-driven syndrome of changes leads to later resurgence in the F2 or later generations. Chronic resurgence poses new threats to global rice production. We review findings on the physiological and molecular mechanisms of chronic planthopper resurgence and suggest research directions that may help manage these new threats.