RESUMO
BACKGROUND: Neisseria gonorrhoeae is identified as a priority pathogen due to its capacity to rapidly develop antimicrobial resistance (AMR). Following the easing of SARS-CoV-2 pandemic travel restrictions across international borders in the state of New South Wales (NSW), Australia, a surge of gonococcal isolates with raised ceftriaxone MIC values were detected. METHODS: All N. gonorrhoeae isolates (nâ=â150) with increased ceftriaxone MIC values in NSW between 1 January 2021 and July 2022 from males and females from all sites were sequenced. RESULTS: A new emergence and rapid expansion of an N. gonorrhoeae ST7827 clone was documented within NSW, Australia and provides further evidence of the ability of N. gonorrhoeae to undergo sufficient genomic changes and re-emerge as a geographically restricted subclone. Mapping AMR determinants to MIC results did not reveal any genomic pattern that correlated with MIC values. CONCLUSIONS: The rapid dissemination and establishment of this clone at the population level is a new and concerning demonstration of the agility of this pathogen, and underscores concerns about similar incursions and establishment of MDR clones. Moreover, it is notable that in this context the AMR genotype-phenotype correlates remain unclear, which requires further investigation to enable better understanding of genomic aspects of AMR in N. gonorrhoeae.
Assuntos
Gonorreia , Neisseria gonorrhoeae , Genótipo , Fenótipo , Áustria/epidemiologia , Neisseria gonorrhoeae/efeitos dos fármacos , Neisseria gonorrhoeae/genética , Gonorreia/epidemiologia , Ceftriaxona/farmacologia , Filogenia , HumanosRESUMO
The United Kingdom has a national immunization programme which includes annual influenza vaccination in school-aged children, using live attenuated influenza vaccine (LAIV). LAIV is given annually, and it is unclear whether repeat administration can affect immunogenicity. Because LAIV is delivered intranasally, pre-existing local antibody might be important. In this study, we analysed banked samples from a study performed during the 2017/18 influenza season to investigate the role of pre-existing influenza-specific nasal immunoglobulin (Ig)A in children aged 6-14 years. Nasopharyngeal swabs were collected prior to LAIV immunization to measure pre-existing IgA levels and test for concurrent upper respiratory tract viral infections (URTI). Oral fluid samples were taken at baseline and 21-28 days after LAIV to measure IgG as a surrogate of immunogenicity. Antibody levels at baseline were compared with a pre-existing data set of LAIV shedding from the same individuals, measured by reverse transcription-polymerase chain reaction. There was detectable nasal IgA specific to all four strains in the vaccine at baseline. However, baseline nasal IgA did not correlate with the fold change in IgG response to the vaccine. Baseline nasal IgA also did not have an impact upon whether vaccine virus RNA was detectable after immunization. There was no difference in fold change of antibody between individuals with and without an URTI at the time of immunization. Overall, we observed no effect of pre-existing influenza-specific nasal antibody levels on immunogenicity, supporting annual immunization with LAIV in children.
Assuntos
Anticorpos Antivirais/imunologia , Imunogenicidade da Vacina/imunologia , Imunoglobulina A/imunologia , Vacinas contra Influenza/imunologia , Influenza Humana/imunologia , Cavidade Nasal/imunologia , Administração Intranasal , Adolescente , Criança , Feminino , Humanos , Imunoglobulina G/imunologia , Vírus da Influenza A Subtipo H1N1/imunologia , Vírus da Influenza A Subtipo H3N2/imunologia , Vacinas contra Influenza/administração & dosagem , Influenza Humana/prevenção & controle , Influenza Humana/virologia , Masculino , Cavidade Nasal/virologia , Vacinação/métodos , Vacinas Atenuadas/administração & dosagem , Vacinas Atenuadas/imunologia , Eliminação de Partículas Virais/imunologiaRESUMO
Cases of glioblastoma multiforme (GBM) metastasizing to the leptomeninges or the intramedullary spine are rare and their prognosis are relatively poor. We present a case of supratentorial glioblastoma WHO grade IV which was later diagnosed to have cervical intramedullary metastasis 7 months after the primary surgery.
Assuntos
Neoplasias Encefálicas , Medula Cervical , Craniotomia/métodos , Glioblastoma/secundário , Laminectomia/métodos , Lobo Parietal , Neoplasias da Medula Espinal , Lobo Temporal , Adulto , Antineoplásicos/uso terapêutico , Protocolos Antineoplásicos , Neoplasias Encefálicas/patologia , Neoplasias Encefálicas/fisiopatologia , Neoplasias Encefálicas/cirurgia , Medula Cervical/diagnóstico por imagem , Medula Cervical/cirurgia , Descompressão Cirúrgica/métodos , Evolução Fatal , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Estadiamento de Neoplasias , Lobo Parietal/diagnóstico por imagem , Lobo Parietal/cirurgia , Radioterapia/métodos , Neoplasias da Medula Espinal/diagnóstico , Neoplasias da Medula Espinal/fisiopatologia , Neoplasias da Medula Espinal/secundário , Neoplasias da Medula Espinal/cirurgia , Técnicas Estereotáxicas , Lobo Temporal/diagnóstico por imagem , Lobo Temporal/cirurgia , Tomografia Computadorizada por Raios X/métodosRESUMO
By midcentury, the U.S.A. will be more ethnically and racially diverse. Skin of colour will soon constitute nearly one-half of the U.S. population, and a full understanding of skin conditions that affect this group is of great importance. Structural and functional differences in the skin, as well as the influence of cultural practices, produce variances in skin disease and presentation based on skin type. In the skin of colour population, dyschromia is a growing concern, and a top chief complaint when patients present to the physician. A thorough understanding of the aetiology and management strategies of facial hyperpigmentation is of importance in caring for those afflicted and also in the development of new therapies.
Assuntos
Dermatoses Faciais/etiologia , Hiperpigmentação/etiologia , Administração Cutânea , Infecções por Alphavirus/complicações , Infecções por Alphavirus/etnologia , Febre de Chikungunya , Dermabrasão/métodos , Fármacos Dermatológicos/uso terapêutico , Combinação de Medicamentos , Dermatoses Faciais/etnologia , Dermatoses Faciais/terapia , Humanos , Hiperpigmentação/etnologia , Hiperpigmentação/terapia , Terapia a Laser/métodos , Líquen Plano/complicações , Líquen Plano/etnologia , Líquen Plano/terapia , Nevo/complicações , Nevo/etnologia , Nevo/terapia , Ocronose/complicações , Ocronose/etnologia , Ocronose/terapia , Neoplasias Cutâneas/complicações , Neoplasias Cutâneas/etnologia , Neoplasias Cutâneas/terapiaRESUMO
Alteration and abnormal epigenetic mechanisms can lead to the aberration of normal biological functions and the occurrence of several diseases. The histone deacetylase (HDAC) family of enzymes is one of the prime regulators of epigenetic functions modifying the histone proteins, and thus, regulating epigenetics directly. HDAC1 is one of those HDACs which have important contributions to cellular epigenetics. The abnormality of HDAC is correlated to the occurrence, progression, and poor prognosis in several disease conditions namely neurodegenerative disorders, cancer cell proliferation, metastasis, chemotherapy resistance, and survival in various cancers. Therefore, the progress of potent and effective HDAC1 inhibitors is one of the prime approaches to combat such diseases. In this study, both regression and classification-based molecular modelling studies were conducted on some AR-42 derivatives as HDAC1 inhibitors to elucidate the crucial structural aspects that are responsible for regulating their biological responses. This study revealed that the molecular polarizability, van der Waals volume, the presence of aromatic rings as well as the higher number of hydrogen bond acceptors might affect prominently their inhibitory activity and might be responsible for proper fitting and interactions at the HDAC1 active site to pertain effective inhibition.
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Histona Desacetilases , Relação Quantitativa Estrutura-Atividade , Histona Desacetilases/metabolismo , Fenilbutiratos , Proliferação de CélulasRESUMO
Present communication reports the physico-chemical and biological quality of seawater and status of benthos of a highly industrialized shore of the north-western coastline of India. The coastal area considered for the present study, encircled by a variety of industries, was divided into two sampling sites and monitored for two consecutive years. Results of the water quality suggest that the obtained values of the physical and chemical parameters of seawater were comparable with data reported earlier. However, data obtained in the biological parameters of the seawater showed a declining trend. Results of the intertidal macrofaunal diversity studies revealed that the muddy upper littoral zones were represented by few species of coelenterata, porifera, arthropoda and mollusca. In the rocky-muddy middle littoral zones, gastropods, stars fishes, corallites, crabs, polychetes and tubeworms were present, whereas, predominantly rocky lower littoral zones were comparatively rich in macrofaunal diversity with small patches of coral colonies. However, when the results obtained in the present study was compared with that of earlier reported data, it was clear that the macrofaunal diversity indeed declined considerably over the years. This may be due to habitat destruction and habitat alteration in the coastline caused by increased anthropogenic activities in the area. Seasonal variations in the population density and abundance were observed in most of the faunal groups except in sessile corals and sponges. This may be due to local migration of the faunal groups towards deeper regions of the Gulf, as supported by the analysis of similarity, to avoid influx of freshwater during monsoon, and high temperature during summer and post monsoon seasons. The overall assessment of different parameters of this study revealed that though the physico- chemical characteristics of the seawater did not varied much from the earlier reported status, the biological characteristics of the seawater and intertidal zone was affected possibly by a high degree of anthropogenic pressure.
Assuntos
Biodiversidade , Indústrias , Invertebrados , Estações do Ano , Poluentes da Água , Água/química , Animais , Índia , Resíduos Industriais , Fitoplâncton , Fatores de Tempo , ZooplânctonRESUMO
Xanthogranulomatous pyelonephritis (XGP) is an uncommon and distinct type of chronic infective pyelonephritis causing destruction of the kidney, severely affecting the renal function. The perinephric adipose tissue and peritoneum is not uncommonly involved. The study was undertaken to decipher the clinicopathologic spectrum of XGP. Forty cases of XGP were diagnosed on histopathology over a period of 13 years (2005-2017). Relevant clinical details and radiological findings were recorded from the case files. Out of a total of 40 cases, 26 were female and 14 were male with a mean age of 39.5 ± 13.6 years. Flank pain was the most common presenting symptom. All the patients had unilateral disease and underwent nephrectomy for a nonfunctional kidney. Gross examination showed enlarged kidney with replacement of cortico-medullary tissue by yellow nodular areas of fatty tissue and dilatation of the pelvicalyceal system. Thirty-six (90%) cases had nephrolithiasis. Histologically, the characteristic feature was the existence of lipid-laden foamy macrophages. Renal parenchymal involvement was diffuse in majority (31, 77.5%). Two (5.0%) of the patients had coexisting carcinoma in the same kidney. Histopathologic examination gives the definitive diagnosis of XGP which relies on the characteristic morphology. Surgical intervention in the form of nephrectomy is the treatment of choice and offers good treatment outcomes.
RESUMO
The accumulation of dicarboxylic acids, particularly long chain, is a prominent feature of Reye's syndrome and diseases of peroxisomal metabolism. We assessed the omega-oxidation of a spectrum of fatty acids in rats and asked whether pretreatment of rats with aspirin, which is known to predispose children to Reye's syndrome, would affect omega-oxidation of long chain fatty acids. We found that aspirin increased liver free fatty acids and increased the capacity for omega-oxidation three- to sevenfold. Omega-oxidation of long chain substrate was stimulated to a greater degree than medium chain substrate and was apparent within one day of treatment, at serum aspirin concentrations below the therapeutic range in humans. The apparent Km for lauric acid was 0.9 microM and 12 microM for palmitate. We also found a difference in the storage stability of activity toward medium and long chain substrate. Saturating concentrations of palmitate had no effect on the formation of dodecanedioic acid, whereas laurate decreased but never eliminated the omega-oxidation of palmitate. 97% of the total laurate omega-oxidative activity recovered was found in the microsomes, but 32% of palmitate omega-oxidative activity was present in the cytosol. These results demonstrate that aspirin is a potent stimulator of omega-oxidation and suggest that there may be multiple enzymes for omega-oxidation with overlapping substrate specificity.
Assuntos
Aspirina/toxicidade , Ácidos Dicarboxílicos/metabolismo , Ácidos Graxos/metabolismo , Síndrome de Reye/induzido quimicamente , Animais , Técnicas In Vitro , Fígado/metabolismo , Masculino , Oxirredução , Ratos , Ratos EndogâmicosRESUMO
Msx2, a member of the highly conserved and widely distributed msh homeobox gene family, is expressed in a variety of sites in the vertebrate embryo, including craniofacial structures, heart, limb buds and otic and optic vesicles. In many of these sites, its expression is regulated by tissue interactions. Here we address the cis-trans regulatory interactions that direct Msx2 expression to specific regions of the embryo and enable it to respond to tissue interactions. We created a series of Msx2-lacZ fusion constructs with varying amounts of Msx2 genomic sequences. These were introduced into mouse embryos and their expression monitored by staining for beta-galactosidase activity. A construct bearing 5.2 kb of 5' flanking sequence, the intron, both exons and 3 kb of 3' flanking sequence was expressed in a pattern that closely resembled that of the endogenous Msx2 gene. In the E12.5 embryo, sites of expression included craniofacial mesenchyme, portions of the neural ectoderm, mesoderm in the distal limb bud and the overlying apical ectodermal ridge (AER). Removal of intronic and 3' UTR sequences slightly altered the pattern of Msx2 expression in the neural ectoderm of the E12 embryo. Deletion of 5' flanking sequences to -0.5 kb eliminated Msx2 expression in all sites except the AER. The proximal Msx2 promoter, including sequences required for the AER-specific expression of the -0.5 lacZ transgene, is highly conserved between mouse and human, one stretch exhibiting 100% identity over 72 bp. This conservation suggests that the AER element is under remarkably tight evolutionary constraint.
Assuntos
Extremidades/embriologia , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Genes Homeobox , Sequência de Aminoácidos , Animais , Composição de Bases , Sequência de Bases , Desenvolvimento Embrionário e Fetal/genética , Feminino , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos CBA , Camundongos Transgênicos , Dados de Sequência Molecular , Iniciação Traducional da Cadeia Peptídica , Regiões Promotoras GenéticasRESUMO
Leprosy, manifesting during adolescence when significant physical and emotional changes are taking place, poses further stress and strain both on the individual and on the family. Based on hospital records, focus group discussions and in-depth interviews, data on 258 adolescent leprosy patients seen at a leprosy referral hospital in Kolkata, India, are presented. The male-female sex ratio was 1.93:1, 56.6% were multibacillary patients and 13.2% had grade 2 disability. At the time of final follow up, 10% of PB and 33% of MB patients had already discontinued treatment. The commonest complication was reaction (14.5%). Adolescents were still dependent on their parents for health matters. Data obtained from questionnaires confirmed the role of social stigma in hiding, delay in starting of MDT and defaulting. Frequent hospital admissions resulted in loss of jobs and disruption of studies and caused psychological disturbances. It is critical to identify and treat adolescent leprosy on a priority basis. Health education and counselling programmes must be more focused and acceptable. Further research is necessary.
Assuntos
Hanseníase/epidemiologia , Adolescente , Atitude Frente a Saúde , Família/psicologia , Feminino , Humanos , Índia/epidemiologia , Hanseníase/tratamento farmacológico , Hanseníase/microbiologia , Hanseníase/psicologia , Masculino , Prevalência , Psicologia do Adolescente , Estereotipagem , Inquéritos e QuestionáriosRESUMO
TCF21 is a basic helix-loop-helix transcription factor that has recently been implicated as contributing to susceptibility to coronary heart disease based on genome wide association studies. In order to identify transcriptionally regulated target genes in a major disease relevant cell type, we performed siRNA knockdown of TCF21 in in vitro cultured human coronary artery smooth muscle cells and compared the transcriptome of siTCF21 versus siCONTROL treated cells. The raw (FASTQ) as well as processed (BED) data from 3 technical replicates per treatment has been deposited with Gene Expression Omnibus (GSE44461).
RESUMO
Mesenchymal stem cells give rise to the progenitors of many differentiated phenotypes, including osteocytes, chrondocytes, myocytes, adipocytes, fibroblasts, and marrow stromal cells, which are capable of self-renewal and undergo expansion in the presence of transforming growth factor-beta1 (TGF-beta1). The present study was designed to test the concept that mesenchymal progenitor cells could be selected and expanded by virtue of their intrinsic physiologic responses to TGF-beta1. Human bone marrow aspirates were initially cultured, under low serum conditions, in collagen pads or gels impregnated with a genetically engineered TGF-beta1 fusion protein bearing an auxiliary von Willebrand's factor-derived collagen-binding domain (TGF-beta1-vWF). Histologic examination of TGF-beta1-vWF-supplemented collagen pads from 8-day cultures revealed the selective survival of a population of mononuclear blastoid cells. The TGF-beta-responsive cells were expanded to form stromal/fibroblastic colonies by serum reconstitution, and further to form osteogenic colonies upon supplementation with osteoinductive factors. In comparative studies, both marrow-derived progenitor cells and mature stromal cells were transduced with a retroviral vector bearing a human factor IX construct. Both the transduced progenitor cells and mature stromal cells expressed the factor IX transgene at levels comparable to those reported for human fibroblasts. Transplantation of murine progenitor cells bearing the human factor IX vector into syngeneic B6CBA mice resulted in detectable circulating levels of the human factor IX antigen. Taken together, these data demonstrate a novel physiologic approach for the selection of mesenchymal precursor cells followed by mitotic expansion, transduction, and transplantation of these progenitor cells with retroviral vectors bearing therapeutic genes.
Assuntos
Células da Medula Óssea , Fator IX/uso terapêutico , Células-Tronco/citologia , Fator de Crescimento Transformador beta/farmacologia , Fator de von Willebrand/farmacologia , Animais , Contagem de Células , Separação Celular , Colágeno/fisiologia , Fator IX/genética , Expressão Gênica , Vetores Genéticos , Humanos , Camundongos , Camundongos Endogâmicos CBA , Ratos , Ratos Endogâmicos F344 , Proteínas Recombinantes de Fusão/farmacologia , Retroviridae/genética , Transplante de Células-Tronco , Células-Tronco/efeitos dos fármacos , TransfecçãoRESUMO
The homeobox gene Msx-2 is expressed specifically in sites of skin appendage formation. To explore its part in skin morphogenesis, we produced transgenic mice expressing Msx-2 under the control of the cytomegalovirus promoter. The skin of these transgenic mice was flaky, exhibiting desquamation and shorter hairs. Histologic analysis showed thickened epidermis with hyperproliferation, which was restricted to the basal layer. Hyperkeratosis was also evident. A wide zone of suprabasal cells were misaligned and coexpressed keratins 14 and 10. There was reduced expression of integrin beta 1 and DCC in the basal layer. Hair follicles were misaligned with a shrunken matrix region. The dermis showed increased cellularity and empty vacuoles. We suggest that Msx-2 is involved in the growth control of skin and skin appendages.
Assuntos
Anormalidades Múltiplas/genética , Proteínas de Ligação a DNA/genética , Epiderme/anormalidades , Genes Homeobox/genética , Folículo Piloso/anormalidades , Animais , Expressão Gênica , Proteínas de Homeodomínio , Camundongos , Camundongos Transgênicos , Pele/crescimento & desenvolvimentoRESUMO
Developmental studies of oncogene expression implicate the Fos and Jun family of transcription factors in the regulation of bone growth and differentiation. Promoters of many developmentally regulated genes, including osteocalcin, a marker of osteoblast differentiation, contain AP-1 sites that bind Fos/Jun dimers. Here, we demonstrate that the selective expression of fos- and jun-related genes is functionally related to the stage of osteoblast growth and differentiation in vitro. During osteoblast proliferation, nuclear protein levels of all seven activating protein-1 (AP-1) members are maximal. Subsequently, during the period of extracellular matrix maturation, levels decline. In fully differentiated osteoblasts, Fra-2 and (to a lesser extent) Jun D are the principal AP-1 members detectable by Western blot analysis. AP-1 complex composition and binding activity also exhibit developmental changes. All Fos and Jun family members are involved in AP-1 complex formation in proliferating cells, whereas Fra-2 and Jun D predominate in AP-1 complexes in differentiated osteoblasts. Overexpression of Fos and Jun family members in ROS 17/2.8 cells markedly affects the expression of an osteocalcin promoter-chloramphenicol acetyltransferase construct. Coexpression of only one AP-1 pair, Fra-2 and Jun D, stimulated reporter expression, whereas coexpression of other AP-1 pairs down-regulated expression (i.e. c-jun and any Fos family member) or had no effect (i.e. Fra-1 and Jun B). Promoter deletion analyses indicate that these effects are site specific. Consequential effects of Fra-2 on osteoblast differentiation are further demonstrated by antisense studies in which osteoblast differentiation and the development of a bone tissue-like organization were suppressed. Consistent with recent findings suggesting that AP-1 complex composition can selectively regulate gene transcription, our findings demonstrate that differential expression of Fos and Jun family members could play a role in the developmental regulation of bone-specific gene expression and, as a result, may be functionally significant for osteoblast differentiation.
Assuntos
Proteínas de Ligação a DNA/fisiologia , Osteoblastos/fisiologia , Proteínas Proto-Oncogênicas c-fos/fisiologia , Proteínas Proto-Oncogênicas c-jun/fisiologia , Fatores de Transcrição/fisiologia , Animais , Diferenciação Celular , Senescência Celular , Antígeno 2 Relacionado a Fos , Expressão Gênica , Osteoblastos/citologia , Osteocalcina/genética , Ratos/embriologia , Fator de Transcrição AP-1/metabolismoRESUMO
Preparation of 9-[(3-18F-fluoro-1-hydroxy-2-propoxy)methyl]-guanine ([18F]-FHPG) for clinical use, and its evaluation as a positron emission tomography (PET) imaging agent for gene incorporation and expression in tumors are reported. In vitro studies in human colon cancer cells, HT-29, transduced with the retroviral vector G1Tk1SvNa and nontransduced (wild type) showed 4, 8, 12, and 15 times higher uptake of the probe in 1, 3, 5, and 7 h, respectively, in transduced cells compared with the controls. In vivo studies in tumor-bearing nude mice demonstrated that the tumor uptake of the radiotracer is three and six-fold higher in 2 and 5 h, respectively, in transduced cells compared with the control cells. These results suggest that [18F]-FHPG is a potential in vivo PET imaging agent for monitoring gene incorporation and expression in gene therapy of cancer.
Assuntos
Radioisótopos de Flúor , Ganciclovir/análogos & derivados , Terapia Genética , Neoplasias Experimentais/terapia , Tomografia Computadorizada de Emissão , Animais , Cromatografia Líquida de Alta Pressão , Ganciclovir/farmacocinética , Células HT29 , Humanos , Camundongos , Camundongos NusRESUMO
The coastal teleost species, Periophthalmus dipes, commonly known as the mudskipper, was exposed to three sublethal concentrations (5, 10 and 15 mg/l) of potassium chromate for three exposure durations (2, 4 and 6 days). The study compares the dose- and duration-dependent effects of Cr(VI), as potassium chromate, on the ATPase systems in various organs of this fish species. In this study, effects of Cr(VI) stress on total ATPase, (Na+,K+)-ATPase, (Ca+2)-ATPase, (Mg+2)-ATPase, (Ca+2, HCO3-)-ATPase and (Mg+2,HCO3-)-ATPase in gills, kidney and intestine were estimated. A general dose- and duration-dependent inhibitory trend was observed. However, it is evident that exposure duration is more important then dose in the inhibition of the activity of the enzymes. At some concentrations, initial stimulation of the activity of some enzymes were also noticed. However, maximum inhibition was observed in higher Cr(VI) concentrations exposed for the longest time. It is possible that this inhibition of the ATPases by Cr(VI) blocked the active transport system of the gill epithelial as well as chloride cells, glomerular and epithelial cells of the tubules and thus altered the osmoregulatory mechanism of the fish. It appears that this heavy metal ion alters the membrane permeability of the intestinal epithelial cells and other layer of cells by altering the activity of ATPases, resulting in a breakdown of the active transport mechanism needed for the absorption of nutrients, ions and metabolites.
Assuntos
Adenosina Trifosfatases/metabolismo , Cromatos/toxicidade , Brânquias/efeitos dos fármacos , Intestinos/efeitos dos fármacos , Rim/efeitos dos fármacos , Compostos de Potássio/toxicidade , Absorção , Adenosina Trifosfatases/efeitos dos fármacos , Animais , Transporte Biológico Ativo , Relação Dose-Resposta a Droga , Peixes , Brânquias/enzimologia , Intestinos/enzimologia , Rim/enzimologia , Poluentes Químicos da Água/toxicidadeRESUMO
Most aphids show cyclical parthenogenesis, have short generation times and complete several generations each season. Two hypotheses have been proposed to account for the adaptive seasonal trends observed in the reproductive strategies of aphids. Firstly, individuals of each generation modify their reproductive strategy in direct response to the conditions they experience during their development. Secondly, the reproductive strategies of the different generations are to a large extent programmed and anticipate seasonal trends in habitat quality. These hypotheses were tested by rearing individuals of three generations of the host-alternating willow-carrot aphid, Cavariella aegopodii, on both willow and carrot. This revealed that the way this aphid allocates resources to gonads and lipid reserves is independent of an aphid's weight and the host plant on which it is reared. In addition each generation shows a specific relationship between offspring size and adult size, which tends to keep the absolute investment in individual offspring relatively constant from generation to generation, inspite of the big differences in adult size between generations. That is, through programmed allometric engineering aphids anticipate the predictable seasonal trends in habitat quality and so more closely track their resources, investing relatively more in gonads when food quality is high and relatively more in lipoidal reserves when food quality is poor.
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Macrophomina phaseolina, the well-known jute pathogenic fungus produces very low levels of both extra- and intracellular carboxymethylcellulase even in the absence of any cellulose as carbon source in the medium. However, the production of these enzymes is greatly induced by soluble carboxymethylcellulose. The carboxymethylcellulase in M. phaseolina is repressed by glucose.
Assuntos
Celulase/biossíntese , Fungos Mitospóricos/enzimologia , Carboximetilcelulose Sódica/metabolismo , Celulase/metabolismo , Meios de Cultura , Grão Comestível , Indução Enzimática , Repressão Enzimática , Glucose/farmacologia , beta-Glucosidase/metabolismoRESUMO
Primary malignant giant cell tumour of bone is extremely rare. It is distinctly separate from benign metastasising giant cell tumour of bone and secondary malignant giant cell tumour which occurs in response to radiotherapy and repeated curettage of benign giant cell tumor. The tumor has high mortality rate. It usually affects lower end of femur and upper end of tibia. Two usually affects lower end of femur and upper end of tibia. Two cases, on involving upper end of tibia and other in vertebra are discussed. Extreme paucity of literature prompted to publish this article. A short review of radiological appearance, histopathological findings and treatment modalities is highlighted.