Common Phenotypic Traits Research Articles

Mouse models for inherited monoamine neurotransmitter disorders.

Several mouse models have been developed to study human defects of primary and secondary inherited monoamine neurotransmitter disorders (iMND). As the field continues to expand, current defects in corresponding mouse models include enzymes and a molecular co-chaperone involved in monoamine synthesis and metabolism (PAH, TH, PITX3, AADC, DBH, MAOA, DNAJC6), tetrahydrobiopterin (BH4) cofactor synthesis and recycling (adGTPCH1/DRD, arGTPCH1, PTPS, SR, DHPR), and vitamin B6 cofactor deficiency (ALDH7A1), as well as defective monoamine neurotransmitter packaging (VMAT1, VMAT2) and reuptake (DAT). No mouse models are available for human DNAJC12 co-chaperone and PNPO-B6 deficiencies, disorders associated with recessive variants that result in decreased stability and function of the aromatic amino acid hydroxylases and decreased neurotransmitter synthesis, respectively. More than one mutant mouse is available for some of these defects, which is invaluable as different variant-specific (knock-in) models may provide more insights into underlying mechanisms of disorders, while complete gene inactivation (knock-out) models often have limitations in terms of recapitulating complex human diseases. While these mouse models have common phenotypic traits also observed in patients, reflecting the defective homeostasis of the monoamine neurotransmitter pathways, they also present with disease-specific manifestations with toxic accumulation or deficiency of specific metabolites related to the specific gene affected. This review provides an overview of the currently available models and may give directions toward selecting existing models or generating new ones to investigate novel pathogenic mechanisms and precision therapies.

Comparison of the Accuracy in Provisional Diagnosis of 22q11.2 Deletion and Williams Syndromes by Facial Photos in Thai Population Between De-Identified Facial Program and Clinicians.

There are more than 6000 genetic syndromes, therefore the recognition of facial patterns may present a challenge for clinicians. The 22q11.2 deletion syndrome (22q11.2 DS) and Williams syndrome (WS) are two different genetic syndromes but share some common phenotypic traits and subtle facial dysmorphisms. Therefore, any tool that would help clinicians recognize genetic syndromes would likely result in a more accurate diagnosis. The syndrome identification accuracy was compared between 2 different facial analysis algorithms (DeepGestalt and GestaltMatcher) of the Face2Gene (F2G) tool and a group of 9 clinicians with different levels of expertise before and after using F2G for a cohort of 64 Thai participants' frontal facial photos divided into 3 groups of 22q11.2 DS, WS and unaffected controls. The higher accuracy from the DeepGestalt algorithm than from clinicians was demonstrated, especially when comparing between the two syndromes. The accuracy was highest when clinicians use the tool combined with their own decision-making process. The tool's second algorithm, GestaltMatcher revealed clear separation among these three groups of photos. The result of F2G outperforming clinicians was not surprising. However, the highest increase in accuracy was with nondysmorphology clinicians using F2G. Face2Gene would be a useful tool to help clinicians in facial recognition of genetic syndromes, before ordering specific tests to confirm the definite diagnosis.

Addressing Doxorubicin Resistance in Bone Sarcomas Using Novel Drug-Resistant Models.

Bone sarcomas have not shown a significant improvement in survival for decades, due, in part, to the development of resistance to current systemic treatments, such as doxorubicin. To better understand those mechanisms mediating drug-resistance we generated three osteosarcoma and one chondrosarcoma cell lines with a stable doxorubicin-resistant phenotype, both in vitro and in vivo. These resistant strains include a pioneer model generated from a patient-derived chondrosarcoma line. The resistant phenotype was characterized by a weaker induction of apoptosis and DNA damage after doxorubicin treatment and a lower migratory capability. In addition, all resistant lines expressed higher levels of ABC pumps; meanwhile, no clear trends were found in the expression of anti-apoptotic and stem cell-related factors. Remarkably, upon the induction of resistance, the proliferation potential was reduced in osteosarcoma lines but enhanced in the chondrosarcoma model. The exposure of resistant lines to other anti-tumor drugs revealed an increased response to cisplatin and/or methotrexate in some models. Finally, the ability to retain the resistant phenotype in vivo was confirmed in an osteosarcoma model. Altogether, this work evidenced the co-existence of common and case-dependent phenotypic traits and mechanisms associated with the development of resistance to doxorubicin in bone sarcomas.

Basket Trials: Review of Current Practice and Innovations for Future Trials.

Advances in biology and immunology have elucidated genetic and immunologic origins of cancer. Innovations in sequencing technologies revealed that distinct cancer histologies shared common genetic and immune phenotypic traits. Pharmacologic developments made it possible to target these alterations, yielding novel classes of targeted agents whose therapeutic potential span multiple tumor types. Basket trials, one type of master protocol, emerged as a tool for evaluating biomarker-targeted therapies among multiple tumor histologies. Conventionally conducted within the phase II setting and designed to estimate high and durable objective responses, basket trials pose challenges to statistical design and interpretation of results. This article reviews basket trials implemented in oncology studies and discusses issues related to their statistical design and analysis.

Description of the first Spanish case of Gerstmann–Sträussler–Scheinker disease with A117V variant: clinical, histopathological and biochemical characterization

Gerstmann–Sträussler–Scheinker disease (GSS) is a rare neurodegenerative illness that belongs to the group of hereditary or familial Transmissible Spongiform Encephalopathies (TSE). Due to the presence of different pathogenic alterations in the prion protein (PrP) coding gene, it shows an enhanced proneness to misfolding into its pathogenic isoform, leading to prion formation and propagation. This aberrantly folded protein is able to induce its conformation to the native counterparts forming amyloid fibrils and plaques partially resistant to protease degradation and showing neurotoxic properties. PrP with A117V pathogenic variant is the second most common genetic alteration leading to GSS and despite common phenotypic and neuropathological traits can be defined for each specific variant, strikingly heterogeneous manifestations have been reported for inter-familial cases bearing the same pathogenic variant or even within the same family. Given the scarcity of cases and their clinical, neuropathological, and biochemical variability, it is important to characterize thoroughly each reported case to establish potential correlations between clinical, neuropathological and biochemical hallmarks that could help to define disease subtypes. With that purpose in mind, this manuscript aims to provide a detailed report of the first Spanish GSS case associated with A117V variant including clinical, genetic, neuropathological and biochemical data, which could help define in the future potential disease subtypes and thus, explain the high heterogeneity observed in patients suffering from these maladies.

Functional Studies of Genetic Variants Associated with Human Diseases in Notch Signaling-Related Genes Using Drosophila.

Rare variants in the many genes related to Notch signaling cause diverse Mendelian diseases that affect myriad organ systems. In addition, genome- and exome-wide association studies have linked common and rare variants in Notch-related genes to common diseases and phenotypic traits. Moreover, somatic mutations in these genes have been observed in many types of cancer, some of which are classified as oncogenic and others as tumor suppressive. While functional characterization of some of these variants has been performed through experimental studies, the number of "variants of unknown significance" identified in patients with diverse conditions keeps increasing as high-throughput sequencing technologies become more commonly used in the clinic. Furthermore, as disease gene discovery efforts identify rare variants in human genes that have yet to be linked to a disease, the demand for functional characterization of variants in these "genes of unknown significance" continues to increase. In this chapter, we describe a workflow to functionally characterize a rare variant in a Notch signaling related gene that was found to be associated with late-onset Alzheimer's disease. This pipeline involves informatic analysis of the variant of interest using diverse human and model organism databases, followed by in vivo experiments in the fruit fly Drosophila melanogaster. The protocol described here can be used to study variants that affect amino acids that are not conserved between human and fly. By "humanizing" the almondex gene in Drosophila with mutant alleles and heterologous genomic rescue constructs, a missense variant in TM2D3 (TM2 Domain Containing 3) was shown to be functionally damaging. This, and similar approaches, greatly facilitate functional interpretations of genetic variants in the human genome and propel personalized medicine.

Biomechanics of T Cell Dysfunctions in Chronic Diseases.

Understanding the mechanisms behind T cell dysfunctions during chronic diseases is critical in developing effective immunotherapies. As demonstrated by several animal models and human studies, T cell dysfunctions are induced during chronic diseases, spanning from infections to cancer. Although factors governing the onset and the extent of the functional impairment of T cells can differ during infections and cancer, most dysfunctional phenotypes share common phenotypic traits in their immune receptor and biophysical landscape. Through the latest developments in biophysical techniques applied to explore cell membrane and receptor–ligand dynamics, we are able to dissect and gain further insights into the driving mechanisms behind T cell dysfunctions. These insights may prove useful in developing immunotherapies aimed at reinvigorating our immune system to fight off infections and malignancies more effectively. The recent success with checkpoint inhibitors in treating cancer opens new avenues to develop more effective, targeted immunotherapies. Here, we highlight the studies focused on the transformation of the biophysical landscape during infections and cancer, and how T cell biomechanics shaped the immunopathology associated with chronic diseases.

Trends in morphological relationships among Gangetic Cyprinids

Cyprinidae is the predominant and most diverse taxonomic group of freshwater fishes, exhibiting enormous diversity in shape, size and biology. The morphological diversity of Indian Cyprinids especially the Gangetic Cyprinids is largely unquantified. Geometric morphometrics (GM) approach is an efficient tool to quantify overall body shape variations and has wide application in taxonomic, evolutionary and ecological studies. In this study, digital photographs of 47 Cyprinid fish species from Ganga River were used to measure geometric body shape so as to evaluate interspecific morphometric relationships. Combined results of principal component analysis (PCA), canonical variate analysis (CVA) and Cluster analysis (CA) revealed interspecific differences in Cyprinid fishes. Phenogram showed that all the species of different genus like Barilius, Garra, Labeo, Pethia, Schizothorax and Tor are clustered together in their respective group. This indicates that species of respective genus share common phenotypic traits and there is evolutionary relatedness among them. The present study showcases the efficient use of digital images and strongly supports the application of cost–effective GM method in discriminating distinct groups and representing the morphological relationships between species of Cyprinid fishes. Overall, we suggest that the body shape disparity and proximity among groups can therefore be used as an effective approach in rapid diagnosis of a species and understanding evolutionary relationships between species.

Spatio-temporal correlates of gene expression and cortical morphology across lifespan and aging

Evidence from neuroimaging and genetic studies supports the concept that brain aging mirrors development. However, it is unclear whether mechanisms linking brain development and aging provide new insights to delay aging and potentially reverse it. This study determined biological mechanisms and phenotypic traits underpinning brain alterations across the lifespan and in aging by examining spatio-temporal correlations between gene expression and cortical volumes using datasets d with the age range from 2 to 82 years. We revealed that a large proportion of genes whose expression was associated with cortical volumes across the lifespan were in astrocytes. These genes, which showed up-regulation during development and down-regulation during aging, contributed to fundamental homeostatic functions of astrocytes. Included among these genes were those encoding components of cAMP, Ras, and retrograde endocannabinoid signaling pathways. Genes associated with cortical volumes in the same data aged above 55 years were also enriched for the sphingolipid, renin-angiotensin system (RAS), proteasome, and TGF-β signaling pathway, which is linked to senescence-associated secretory phenotypes. Neuroticism, drinking, and smoking were the common phenotypic traits in the lifespan and aging, while memory was the unique phenotype associated with aging. These findings provide biological mechanisms mirroring development and aging as well as unique to aging.

Clinicopathological and dermoscopic features of amelanotic and hypomelanotic melanoma: a retrospective multicentric study.

Amelanotic and hypomelanotic melanoma (AHM) has a higher risk of delayed diagnosis and a significant lower 5-year melanoma-specific survival compared to pigmented melanoma. Our aim was the evaluation of the clinicopathological/dermoscopic features of amelanotic melanoma (AM) and hypomelanotic melanoma (HM). All participants had a personal history of AHM. We defined HM as showing clinical/dermoscopic pigmentation in<25% of the lesion's surface and histopathological focal pigmentation, while AM as melanomas with clinical/dermoscopic and histopathological absence of pigmentation. The most common phenotypic traits among the 145 AHM patients were as follows: phototype II, blue-grey eyes, and dark brown hair. Red hair was present in 23.8% AHM cases (AM=22.60%; HM=25.80%). The most affected area was the back (29.5%). A total of 67.1% were classified as AM and 32.9% as HM. The most represented hair colors in AM and HM were, respectively, blonde and dark brown hair. Median Breslow thickness was 1.7 mm, superficial spreading melanoma (SSM) and nodular melanoma (NM) were the most represented histotypes, and mitotic rate >1×mm2 was reported in 73.3% cases, and regression was significantly more present in HM. Dermoscopy showed high prevalence of white structureless zones (63.4%), linear looped vessels (58.8%), linear irregular vessels (50.0%), and arborizing vessels (47.2%). Multivariate logistic regression confirmed the association between the presence of pigmentation and the following: histological regression, dermoscopic globules, and arborizing vessels. Predominance of red hair in AHM patients was not confirmed. AHM affects mostly intermittent sun-exposed body areas. The deeper median Breslow thickness (versus pigmented melanoma), the association of AM with the nodular histotype, and the high mitotic rate highlight the AHM's aggressiveness. HM's higher levels of regression can be explained by the presence of pigmentation, driving the underlying immune response. AHM showed a polymorphous vascular pattern and significant presence of arborizing vessels (especially HM).

Aging-associated sinus arrest and sick sinus syndrome in adult zebrafish.

Because of its powerful genetics, the adult zebrafish has been increasingly used for studying cardiovascular diseases. Considering its heart rate of ~100 beats per minute at ambient temperature, which is very close to human, we assessed the use of this vertebrate animal for modeling heart rhythm disorders such as sinus arrest (SA) and sick sinus syndrome (SSS). We firstly optimized a protocol to measure electrocardiogram in adult zebrafish. We determined the location of the probes, implemented an open-chest microsurgery procedure, measured the effects of temperature, and determined appropriate anesthesia dose and time. We then proposed an PP interval of more than 1.5 seconds as an arbitrary criterion to define an SA episode in an adult fish at ambient temperature, based on comparison between the current definition of an SA episode in humans and our studies of candidate SA episodes in aged wild-type fish and Tg(SCN5A-D1275N) fish (a fish model for inherited SSS). With this criterion, a subpopulation of about 5% wild-type fish can be considered to have SA episodes, and this percentage significantly increases to about 25% in 3-year-old fish. In response to atropine, this subpopulation has both common SSS phenotypic traits that are shared with the Tg(SCN5A-D1275N) model, such as bradycardia; and unique SSS phenotypic traits, such as increased QRS/P ratio and chronotropic incompetence. In summary, this study defined baseline SA and SSS in adult zebrafish and underscored use of the zebrafish as an alternative model to study aging-associated SSS.

La onomástica de nombres erróneos en la construcción de andinidad fallida y débil andeancia: el imperativo de microrefugios bioculturales en los Andes

Buscamos (re)construir una narrativa geocrítica para la esencia del paisaje al (re)escribir las especificidades de montaña que impriman atributos culturales en los paisajes andinos tropicales y templados, creando un trilema de identidad único para la gente de las tierras altas de América del Sur. Usamos la onomástica como un estudio de la individualidad errada con un enfoque post-estructuralista para definir “lo andino” dentro de la geoecología humanística; por lo tanto, incorporamos nociones relacionadas con los atributos fenotípicos de Andeanidad, junto con las propiedades crípticas emergentes de Andeancia y las condiciones místicas de espiritualidad de Andeanitud, para producir una nueva trifecta de construcción ecoregional, con una epistemología desafiante para el paisaje patrimonial biocultural basado en el conocimiento tradicional, apropiado dialécticamente de lo viejo a lo nuevo, de lo foráneo a lo nativo y de lo original a lo copiado. Por lo tanto, la dinámica identidad heterogénea imaginada de la gente andina está caracterizada por un flujo dinámico y evolutivo del paisaje montano. Argumentamos que la nomenclatura aún se adapta a marcos de cambio ambiental global; así, está aún sujeta a deterioro a no ser que ciertos microrefugios bioculturales puedan mantener la memoria del paisaje andino vivo. Con una revisión de la hermenéutica de Andes, debido a las variantes (c.f. grafiosis) que incorporaron palabras basadas en Kichwa, Kañary o Mapudungun en el léxico hegemónico del expansionismo colonial de los términos castellanos, apelamos a la inclusión de los descriptores vernáculos en vez del santoral romano y la efemérides patriótica utilizada para nombrar los atributos geográficos en la Sudamérica andina. Pedimos restaurar los descriptores vernáculos con el lenguaje usado por los pueblos originarios, su toponimia y onomatopeya, para atraer el reconocimiento político y para vigorizar el orgullo del patrimonio ancestral de las comunidades de montaña para refuerzo de su bienestar en los microrefugios bioculturales. Al cambiar los nombres impuestos por la geografía imperial colonial a las palabras vernáculas u otros locativos no hegemónicos de escolaridad decolonial, se ayudará a obtener un mejor ‘sentido del lugar’ en los Andes e incrementará la posibilidad de (super)vivencia y (re)generación de los paisajes productivos socioecológicos ancestrales andinos.

The impact of immobilisation and inflammation on the regulation of muscle mass and insulin resistance: different routes to similar end-points.

Loss of muscle mass and insulin sensitivity are common phenotypic traits of immobilisation and increased inflammatory burden. The suppression of muscle protein synthesis is the primary driver of muscle mass loss in human immobilisation, and includes blunting of post‐prandial increases in muscle protein synthesis. However, the mechanistic drivers of this suppression are unresolved. Immobilisation also induces limb insulin resistance in humans, which appears to be attributable to the reduction in muscle contraction per se. Again mechanistic insight is missing such that we do not know how muscle senses its “inactivity status” or whether the proposed drivers of muscle insulin resistance are simply arising as a consequence of immobilisation. A heightened inflammatory state is associated with major and rapid changes in muscle protein turnover and mass, and dampened insulin‐stimulated glucose disposal and oxidation in both rodents and humans. A limited amount of research has attempted to elucidate molecular regulators of muscle mass loss and insulin resistance during increased inflammatory burden, but rarely concurrently. Nevertheless, there is evidence that Akt (protein kinase B) signalling and FOXO transcription factors form part of a common signalling pathway in this scenario, such that molecular cross‐talk between atrophy and insulin signalling during heightened inflammation is believed to be possible. To conclude, whilst muscle mass loss and insulin resistance are common end‐points of immobilisation and increased inflammatory burden, a lack of understanding of the mechanisms responsible for these traits exists such that a substantial gap in understanding of the pathophysiology in humans endures.

ACTUALY QUESTIONS OF FORENSC MEDICAL DERMATOGLIFICS

The article examines the historical information regarding the use of dermatoglyphics during the identification of an unknown person. Outlined by new perspectives of using modern developments in the field of forensic criminology in studying skin patterns and the development of diagnostic algorithms common phenotypic traits of human. The analysis of the latest scientific publications on the given problem was carried out.

EXPRESS PREDICTION OF EXTERNAL DISTINCTIVE FEATURES OF PERSON USING THE PROGRAM OF DERMATOGLYPHICS FOR PREDICTION

The aim of our study was to investigate the current state of computer identification applications, such as artificial neural networks. The material of our study were antroposcopic and anthropometric parameters obtained from 180 male and females aged 18–55 years living in the Ivano-Frankivsk region and belonging to Boiko, Lemko or Hutsul ethno-territorial group. Prints of comb pattern of the toes obtained by scanning with Futronic's FS80 USB2.0 Fingerprint Scanner using the program ftrScanApiEx.exe. followed by the transfer of data to a personal computer. For statistical processing of the obtained data we use STATISTICA 12 from the company StatSoft. Construction of neural networks was carried out using Neural Networks. As a result of our research there was carried out the prediction of anthropometric and antroposcopic parameters (ethno-territorial and gender belonging, etc.) through the use of dermatoglyphic parameters of the hands and feet in 180 people living in the Ivano-Frankivsk region. The proposed method allowed to obtain the results with a forecasts probability 73–90 %. The use of above algorithm of actions allowed a 50 % increase of quality of identification of unknown person for using dermatoglyphic method and 67 % facilitatation of the process of identification (of quantitative and qualitative calculations, determining correlations between parameters) in comparison with previously known manner. Therefore, our proposed method can be used as an express diagnostics of common phenotypic traits of the person (ethno-territorial affiliation, gender, etc.) at admission of mass victims (natural disasters, acts of terrorism, armed conflicts, man-made disasters, etc.), it doesn’t not require a long time for conducting, specially trained staff and is inexpensive.Conclusions: The possibility of predicting external-recognizing features of a person such as etno-racial belonging, sex, anthropometric and antroposcopic parameters will allow widely use dermatoglyphic method at the level with other methods in conducting forensic identification of impersonal, fragmented and putrefactive modified corpses.

History of development and up-to-date tendency

The article examines the historical information regarding the use of dermatoglyphics during the identification of an unknown person. Outlined by new perspectives of using modern developments in the field of forensic criminology in studying skin patterns and the development of diagnostic algorithms common phenotypic traits of man.

Genotypic and phenotypic relatedness of Pseudomonas aeruginosa isolates among the major cystic fibrosis patient cohort in Italy.

BackgroundPseudomonas aeruginosa is the predominant pathogen associated with the decline of pulmonary function in cystic fibrosis (CF) patients. Both environment-to-host acquisition and patient-to-patient transmission have been described for P. aeruginosa infection. Epidemic clones and bacterial phenotypic adaptation to the CF lung have been recognised as independent risk factors for disease progression. So far, there is no established link between genotypic prevalence and phenotypic traits. Here, we look at the major CF patient cohort in Italy to identify shared P. aeruginosa clones and associated common phenotypic traits.ResultsA comprehensive analysis of P. aeruginosa genotypes to determine the presence of high-risk shared clones and their association to specific phenotypic traits has been performed in a major Italian CF centre. Pulsed-field gel electrophoresis (PFGE) of P. aeruginosa isolates from 338 CF subjects identified 43 profiles shared by two or more patients and 214 profiles exclusive to individual patients. There was no evidence of a P. aeruginosa outbreak, but four most prevalent pulsotypes were detected. Common phenotypic traits were recorded intra-pulsotypes, but we detected heterogeneity inter-pulsotypes. Two of the four major pulsotypes included P. aeruginosa isolates with hallmarks of adaptation to the CF airways, including loss of motility, low production of siderophore, pyocyanin and proteases, and antibiotic resistance. One of these pulsotypes grouped a high percentage of hypermutable isolates. No clear correlation between epidemiological and clinical data was found.ConclusionsWe conclude that CF patients of this cohort shared common pulsotypes, but their phenotypic heterogeneity indicates an absence of specific traits associated to P. aeruginosa genotypic prevalence.Electronic supplementary materialThe online version of this article (doi:10.1186/s12866-016-0760-1) contains supplementary material, which is available to authorized users.

Functional dyadicity and heterophilicity of gene-gene interactions in statistical epistasis networks

BackgroundThe interaction effect among multiple genetic factors, i.e. epistasis, plays an important role in explaining susceptibility on common human diseases and phenotypic traits. The uncertainty over the number of genetic attributes involved in interactions poses great challenges in genetic association studies and calls for advanced bioinformatics methodologies. Network science has gained popularity in modeling genetic interactions thanks to its structural characterization of large numbers of entities and their complex relationships. However, little has been done on functionally interpreting statistically inferred epistatic interactions using networks.ResultsIn this study, we propose to characterize gene functional properties in the context of interaction network structure. We used Gene Ontology (GO) to functionally annotate genes as vertices in a statistical epistasis network, and quantitatively characterize the correlation between the distribution of gene functional properties and the network structure by measuring dyadicity and heterophilicity of each functional category in the network. These two parameters quantify whether genetic interactions tend to occur more frequently for genes from the same functional category, i.e. dyadic effect, or more frequently for genes from across different functional categories, i.e. heterophilic effect.ConclusionsBy applying this framework to a population-based bladder cancer dataset, we were able to identify several GO categories that have significant dyadicity or heterophilicity associated with bladder cancer susceptibility. Thus, our informatics framework suggests a new methodology for embedding functional analysis in network modeling of statistical epistasis in genetic association studies.

Staphylococcus pseudintermedius can be misdiagnosed as Staphylococcus aureus in humans with dog bite wounds.

The purpose of this study was to investigate whether S. pseudintermedius is misdiagnosed as S. aureus by clinical laboratories when isolated fromhumans with dog bite wounds. In addition, we attempted to determine whether S. pseudintermedius isolates related to dog bite wounds share phenotypic and genotypic traits. S. pseudintermedius was identified by PCR targeting the nuc gene. Isolates were tested for antibiotic susceptibility using VetMIC GP-mo microdilution panels. The occurrence of genes encoding leukocidins, exfoliatins, pyrogenic toxin superantigens and enterotoxins was determined by PCR. The relatedness of S. pseudintermedius isolates was investigated using Multi Locus Sequence Typing (MLST). Out of 101 isolates defined as S. aureus by human clinical microbiology laboratories, 13 isolates were re-identified as S. pseudintermedius and one isolate was confirmed to carry the mecA gene, i.e. methicillin-resistant (MRSP). The MRSP isolate was also defined as multi-resistant. Two methicillin-susceptible S. pseudintermedius isolates were also multi-resistant and five were susceptible to all antibiotics tested. With the exception of three S. pseudintermedius isolates belonging to multi locus sequence type (MLST) 158, all the isolates belonged to unique STs. All isolates contained lukS/F-I, siet and se-int, and expA were identified in two isolates and expB and sec canine-sel in one isolate respectively. S. pseudintermedius is frequently misdiagnosed as S. aureus from humans with dog bite wounds showing that it can act as an opportunistic pathogen in humans. No common phenotypic and genotypic traits shared by the S. pseudintermedius isolates could be identified.

Isolation and characterization of diverse antimicrobial lipopeptides produced by Citrobacter and Enterobacter.

BackgroundIncreasing multidrug-resistance in bacteria resulted in a greater need to find alternative antimicrobial substances that can be used for clinical applications or preservation of food and dairy products. Research on antimicrobial peptides including lipopeptides exhibiting both narrow and broad spectrum inhibition activities is increasing in the recent past. Therefore, the present study was aimed at isolation and characterization of antimicrobial lipopeptide producing bacterial strains from fecal contaminated soil sample.ResultsThe phenotypic and 16S rRNA gene sequence analysis of all isolates identified them as different species of Gram-negative genera Citrobacter and Enterobacter. They exhibited common phenotypic traits like citrate utilization, oxidase negative and facultative anaerobic growth. The HPLC analysis of solvent extracts obtained from cell free fermented broth revealed the presence of multiple antimicrobial lipopeptides. The comprehensive mass spectral analysis (MALDI-TOF MS and GC-MS) of HPLC purified fractions of different isolates revealed that the lipopeptides varied in their molecular weight between (m/z) 607.21 to 1536.16 Da. Isomers of mass ion m/z 984/985 Da was produced by all strains. The 1495 Da lipopeptides produced by strains S-3 and S-11 were fengycin analogues and most active against all strains. While amino acid analysis of lipopeptides suggested most of them had similar composition as in iturins, fengycins, kurstakins and surfactins, differences in their β-hydroxy fatty acid content proposed them to be isoforms of these lipopeptides.ConclusionAlthough antimicrobial producing strains can be used as biocontrol agents in food preservation, strains with ability to produce multiple antimicrobial lipopeptides have potential applications in biotechnology sectors such as pharmaceutical and cosmetic industry. This is the first report on antibacterial lipopeptides production by strains of Citrobacter and Enterobacter.