Lessons from lonely flies: Molecular and neuronal mechanisms underlying social isolation.

Animals respond to changes in the environment which affect their internal state by adapting their behaviors. Social isolation is a form of passive environmental stressor that alters behaviors across animal kingdom, including humans, rodents, and fruit flies. Social isolation is known to increase violence, disrupt sleep and increase depression leading to poor mental and physical health. Recent evidences from several model organisms suggest that social isolation leads to remodeling of the transcriptional and epigenetic landscape which alters behavioral outcomes. In this review, we explore how manipulating social experience of fruit fly Drosophila melanogaster can shed light on molecular and neuronal mechanisms underlying isolation driven behaviors. We discuss the recent advances made using the powerful genetic toolkit and behavioral assays in Drosophila to uncover role of neuromodulators, sensory modalities, pheromones, neuronal circuits and molecular mechanisms in mediating social isolation. The insights gained from these studies could be crucial for developing effective therapeutic interventions in future.

FKBP1A upregulation correlates with poor prognosis and increased metastatic potential of HNSCC.

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common malignancy globally. The etiology of HNSCC is multifactorial, including cellular stress induced by a tobacco smoking, tobacco chewing excess alcohol consumption, and human papillomavirus infection. The induction of stress includes autophagy as one of the response pathways in maintaining homeostatic equilibrium. We evaluated the expression of autophagy-related genes in HNSCC tissues from RNA sequencing datasets and identified 19 genes correlated with poor prognosis and 18 genes correlated with improved prognosis of HNSCC patients. Further analysis of independent gene expression datasets revealed that ATG12, HSP90AB1, and FKBP1A are overexpressed in HNSCC and correlate with poor prognosis, whereas the overexpression of ANXA1, FOS, and ULK3 correlates with improved prognosis. Using independent datasets, we also found that ATG12, HSP90AB1, and FKBP1A expression increased with an increase in the T-stage of HNSCC. Among all the datasets analyzed, FKBP1A was overexpressed in HNSCC and was strongly associated with lymph node metastasis in multiple in silico datasets. In conclusion, our analysis indicates dynamic alterations in autophagy genes during HNSCC and warrants further investigation, specifically on FKBP1A and its role in tumor progression and metastasis.

Regulation of Social Stress and Neural Degeneration by Activity-Regulated Genes and Epigenetic Mechanisms in Dopaminergic Neurons.

Transcriptional and epigenetic regulation of both dopaminergic neurons and their accompanying glial cells is of great interest in the search for therapies for neurodegenerative disorders such as Parkinson's disease (PD). In this review, we collate transcriptional and epigenetic changes identified in adult Drosophila melanogaster dopaminergic neurons in response to either prolonged social deprivation or social enrichment, and compare them with changes identified in mammalian dopaminergic neurons during normal development, stress, injury, and neurodegeneration. Surprisingly, a small set of activity-regulated genes (ARG) encoding transcription factors, and a specific pattern of epigenetic marks on gene promoters, are conserved in dopaminergic neurons over the long evolutionary period between mammals and insects. In addition to their classical function as immediate early genes to mark acute neuronal activity, these ARG transcription factors are repurposed in both insects and mammals to respond to chronic perturbations such as social enrichment, social stress, nerve injury, and neurodegeneration. We suggest that these ARG transcription factors and epigenetic marks may represent important targets for future therapeutic intervention strategies in various neurodegenerative disorders including PD.

The neuropeptide Drosulfakinin regulates social isolation-induced aggression in Drosophila.

Social isolation strongly modulates behavior across the animal kingdom. We utilized the fruit fly Drosophila melanogaster to study social isolation-driven changes in animal behavior and gene expression in the brain. RNA-seq identified several head-expressed genes strongly responding to social isolation or enrichment. Of particular interest, social isolation downregulated expression of the gene encoding the neuropeptide Drosulfakinin (Dsk), the homologue of vertebrate cholecystokinin (CCK), which is critical for many mammalian social behaviors. Dsk knockdown significantly increased social isolation-induced aggression. Genetic activation or silencing of Dsk neurons each similarly increased isolation-driven aggression. Our results suggest a U-shaped dependence of social isolation-induced aggressive behavior on Dsk signaling, similar to the actions of many neuromodulators in other contexts.

Enabling cell-type-specific behavioral epigenetics in Drosophila: a modified high-yield INTACT method reveals the impact of social environment on the epigenetic landscape in dopaminergic neurons.

BACKGROUND: Epigenetic mechanisms play fundamental roles in brain function and behavior and stressors such as social isolation can alter animal behavior via epigenetic mechanisms. However, due to cellular heterogeneity, identifying cell-type-specific epigenetic changes in the brain is challenging. Here, we report the first use of a modified isolation of nuclei tagged in specific cell type (INTACT) method in behavioral epigenetics of Drosophila melanogaster, a method we call mini-INTACT. RESULTS: Using ChIP-seq on mini-INTACT purified dopaminergic nuclei, we identified epigenetic signatures in socially isolated and socially enriched Drosophila males. Social experience altered the epigenetic landscape in clusters of genes involved in transcription and neural function. Some of these alterations could be predicted by expression changes of four transcription factors and the prevalence of their binding sites in several clusters. These transcription factors were previously identified as activity-regulated genes, and their knockdown in dopaminergic neurons reduced the effects of social experience on sleep. CONCLUSIONS: Our work enables the use of Drosophila as a model for cell-type-specific behavioral epigenetics and establishes that social environment shifts the epigenetic landscape in dopaminergic neurons. Four activity-related transcription factors are required in dopaminergic neurons for the effects of social environment on sleep.

Repetitive aggressive encounters generate a long-lasting internal state in Drosophila melanogaster males.

Multiple studies have investigated the mechanisms of aggressive behavior in Drosophila; however, little is known about the effects of chronic fighting experience. Here, we investigated if repeated fighting encounters would induce an internal state that could affect the expression of subsequent behavior. We trained wild-type males to become winners or losers by repeatedly pairing them with hypoaggressive or hyperaggressive opponents, respectively. As described previously, we observed that chronic losers tend to lose subsequent fights, while chronic winners tend to win them. Olfactory conditioning experiments showed that winning is perceived as rewarding, while losing is perceived as aversive. Moreover, the effect of chronic fighting experience generalized to other behaviors, such as gap-crossing and courtship. We propose that in response to repeatedly winning or losing aggressive encounters, male flies form an internal state that displays persistence and generalization; fight outcomes can also have positive or negative valence. Furthermore, we show that the activities of the PPL1-γ1pedc dopaminergic neuron and the MBON-γ1pedc>α/ß mushroom body output neuron are required for aversion to an olfactory cue associated with losing fights.

Bioprospecting and biotechnological applications of fungal laccase.

Laccase belongs to a small group of enzymes called the blue multicopper oxidases, having the potential ability of oxidation. It belongs to enzymes, which have innate properties of reactive radical production, but its utilization in many fields has been ignored because of its unavailability in the commercial field. There are diverse sources of laccase producing organisms like bacteria, fungi and plants. In fungi, laccase is present in Ascomycetes, Deuteromycetes, Basidiomycetes and is particularly abundant in many white-rot fungi that degrade lignin. Laccases can degrade both phenolic and non-phenolic compounds. They also have the ability to detoxify a range of environmental pollutants. Due to their property to detoxify a range of pollutants, they have been used for several purposes in many industries including paper, pulp, textile and petrochemical industries. Some other application of laccase includes in food processing industry, medical and health care. Recently, laccase has found applications in other fields such as in the design of biosensors and nanotechnology. The present review provides an overview of biological functions of laccase, its mechanism of action, laccase mediator system, and various biotechnological applications of laccase obtained from endophytic fungi.

Evaluation of bioactive secondary metabolites from endophytic fungus Pestalotiopsis neglecta BAB-5510 isolated from leaves of Cupressus torulosa D.Don.

Six endophytic fungi were isolated from Cupressus torulosa D.Don and identified phenotypically and genotypically. The fungal cultures were further grown and the culture was extracted by two organic solvents methanol and ethyl acetate. The screening was carried out using the agar well diffusion method against human pathogen such as Escherichia coli, Salmonella typhimurium, Bacillus subtilis and Staphylococcus aureus. Isolated strain of Pestalotiopsis sp. was showing prominent antibacterial activity. The crude methanol and ethyl acetate extract of Pestalotiopsis sp. showed MIC of 6.25 mg/mL for S. typhimurium and S. aureus which showed its efficacy as a potent antimicrobial. The phytochemical screening revealed the existence of a diverse group of secondary metabolites in the crude extracts of the endophytic fungi that resembled those in the host plant extracts. On the basis of phenotypic characteristics and rDNA sequencing of the ITS region of the endophyte was identified as P. neglecta which turned out to be a promising source of bioactive compounds. There is little known about endophytes from C. torulosa D.Don. In this paper we studied in detail the identification of isolated endophytic fungi P. neglecta from C. torulosa D.Don and characterization of its active metabolite compounds. The partially purified second fraction (PPF) extracted from the fungal culture supernatant was subjected to gas chromatography followed by mass spectrometry which revealed the presence of many phytochemicals. These results indicate that endophytic fungi P. neglecta isolated from medicinal plants could be a potential source for bioactive compounds and may find potential use in pharmaceutical industry.

Modern molecular approaches for analyzing microbial diversity from mushroom compost ecosystem.

Biosphere is a store house of various microorganisms that may be employed to isolate and exploit microbes for environmental, pharmaceutical, agricultural and industrial applications. There is restricted data regarding the structure and dynamics of microbial communities in several ecosystems because only a little fraction of microbial diversity is accessible by culture methods. Owing to limitations of traditional enrichment methods and pure culture techniques, microbiological studies have offered a narrow portal for investigating microbial flora. The bacterial community represented by the morphological and nutritional criteria failed to provide a natural taxonomic order according to the evolutionary relationship. Genetic diversity among the isolates recovered from mushroom compost has not been widely studied. To understand genetic diversity and community composition of the mushroom compost microflora, different approaches are now followed by taxonomists, to characterize and identify isolates up to species level. Molecular microbial ecology is an emerging discipline of biology under molecular approach which can provide complex community profiles along with useful phylogenetic information. The genomic era has resulted in the development of new molecular tools and techniques for study of culturable microbial diversity including the DNA base ratio (mole% G + C), DNA-DNA hybridization, DNA microarray and reverse sample genome probing. In addition, non-culturable diversity of mushroom compost ecosystem can be characterized by employing various molecular tools which would be discussed in the present review.

ChIP for Hox proteins from Drosophila imaginal discs.

Chromatin immunoprecipitation (ChIP) is a technique that reveals in vivo location of a protein bound to DNA. ChIP coupled with DNA microarrays (ChIP-chip) or next-generation sequencing (ChIP-seq) allows for identification of binding sites of transcription factors on a global scale. Here we describe a protocol for ChIP to identify binding of the Ultrabithorax (Ubx) Hox transcription factors from imaginal discs of Drosophila larvae. The protocol can be extended to other model organisms and transcription factors.

Genome-level identification of targets of Hox protein Ultrabithorax in Drosophila: novel mechanisms for target selection.

Hox proteins are transcription factors and key regulators of segmental identity along the anterior posterior axis across all bilaterian animals. Despite decades of research, the mechanisms by which Hox proteins select and regulate their targets remain elusive. We have carried out whole-genome ChIP-chip experiments to identify direct targets of Hox protein Ultrabithorax (Ubx) during haltere development in Drosophila. Direct targets identified include upstream regulators or cofactors of Ubx. Homothorax, a cofactor of Ubx during embryonic development, is one such target and is required for normal specification of haltere. Although Ubx bound sequences are conserved amongst various insect genomes, no consensus Ubx-specific motif was detected. Surprisingly, binding motifs for certain transcription factors that function either upstream or downstream to Ubx are enriched in these sequences suggesting complex regulatory loops governing Ubx function. Our data supports the hypothesis that specificity during Hox target selection is achieved by associating with other transcription factors.