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1.
BMC Genomics ; 21(1): 799, 2020 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-33198642

RESUMO

BACKGROUND: Common bean is an important staple crop in the tropics of Africa, Asia and the Americas. Particularly smallholder farmers rely on bean as a source for calories, protein and micronutrients. Drought is a major production constraint for common bean, a situation that will be aggravated with current climate change scenarios. In this context, new tools designed to understand the genetic basis governing the phenotypic responses to abiotic stress are required to improve transfer of desirable traits into cultivated beans. RESULTS: A multiparent advanced generation intercross (MAGIC) population of common bean was generated from eight Mesoamerican breeding lines representing the phenotypic and genotypic diversity of the CIAT Mesoamerican breeding program. This population was assessed under drought conditions in two field trials for yield, 100 seed weight, iron and zinc accumulation, phenology and pod harvest index. Transgressive segregation was observed for most of these traits. Yield was positively correlated with yield components and pod harvest index (PHI), and negative correlations were found with phenology traits and micromineral contents. Founder haplotypes in the population were identified using Genotyping by Sequencing (GBS). No major population structure was observed in the population. Whole Genome Sequencing (WGS) data from the founder lines was used to impute genotyping data for GWAS. Genetic mapping was carried out with two methods, using association mapping with GWAS, and linkage mapping with haplotype-based interval screening. Thirteen high confidence QTL were identified using both methods and several QTL hotspots were found controlling multiple traits. A major QTL hotspot located on chromosome Pv01 for phenology traits and yield was identified. Further hotspots affecting several traits were observed on chromosomes Pv03 and Pv08. A major QTL for seed Fe content was contributed by MIB778, the founder line with highest micromineral accumulation. Based on imputed WGS data, candidate genes are reported for the identified major QTL, and sequence changes were identified that could cause the phenotypic variation. CONCLUSIONS: This work demonstrates the importance of this common bean MAGIC population for genetic mapping of agronomic traits, to identify trait associations for molecular breeding tool design and as a new genetic resource for the bean research community.


Assuntos
Phaseolus , África , Ásia , Mapeamento Cromossômico , Secas , Phaseolus/genética , Fenótipo , Melhoramento Vegetal , Locos de Características Quantitativas
2.
World J Microbiol Biotechnol ; 33(11): 198, 2017 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-28988302

RESUMO

Alginate is a linear polysaccharide that can be used for different applications in the food and pharmaceutical industries. These polysaccharides have a chemical structure composed of subunits of (1-4)-ß-D-mannuronic acid (M) and its C-5 epimer α-L-guluronic acid (G). The monomer composition and molecular weight of alginates are known to have effects on their properties. Currently, these polysaccharides are commercially extracted from seaweed but can also be produced by Azotobacter vinelandii and Pseudomonas spp. as an extracellular polymer. One strategy to produce alginates with different molecular weights and with reproducible physicochemical characteristics is through the manipulation of the culture conditions during fermentation. This mini-review provides a comparative analysis of the metabolic pathways and molecular mechanisms involved in alginate polymerization from A. vinelandii and Pseudomonas spp. Different fermentation strategies used to produce alginates at a bioreactor laboratory scale are described.


Assuntos
Alginatos/metabolismo , Azotobacter vinelandii/crescimento & desenvolvimento , Pseudomonas/crescimento & desenvolvimento , Alginatos/química , Azotobacter vinelandii/genética , Azotobacter vinelandii/metabolismo , Reatores Biológicos , Fermentação , Ácido Glucurônico/química , Ácido Glucurônico/metabolismo , Ácidos Hexurônicos/química , Ácidos Hexurônicos/metabolismo , Redes e Vias Metabólicas , Peso Molecular , Pseudomonas/genética , Pseudomonas/metabolismo
3.
Zootaxa ; 3785: 87-94, 2014 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-24872173

RESUMO

The third instar larvae of Gepus invisus and Solter liber are comparatively described and illustrated for the first time with a particular emphasis on genus level characters. Larval morphology confirms a close relationship between these genera as they differ only in minor characters.


Assuntos
Insetos/anatomia & histologia , Insetos/classificação , África do Norte , Animais , Demografia , Larva/anatomia & histologia , Larva/classificação , Oriente Médio , Especificidade da Espécie
4.
J Surg Case Rep ; 2024(4): rjae234, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38638927

RESUMO

Impalement injuries happen when an object penetrates a body cavity or organ and remains in situ. We present a case of a 35-year-old fisherman whose act of violence resulted in the lodging of an antique iron spear in segment V of the liver, which was then referred to our institution on the day after the accident. Despite the challenges posed by patient transfer, diagnosis, resuscitation, and, most importantly, handling in the operating room, the object was successfully removed via hepatotomy, and the patient is now in good health. Impalement by an ancient African iron spear, repurposed as a fishing tool in modern times, remains undocumented in the literature, necessitating reporting and a call for further research by the medical community into managing impalement injuries of varying severity.

5.
Ann Occup Hyg ; 57(8): 1020-9, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23704136

RESUMO

BACKGROUND: There are increasing reports of allergies and respiratory symptoms among workers in the fish processing industry, coinciding with an increasing use of high-pressure water in the processing plants. However, few studies have measured exposure in these work environments. OBJECTIVES: The aim of this study was to characterize the occupational exposure of workers to herring antigen and to screen environmental factors at a herring (Clupea harengus) plant in which new and more encapsulated filleting machines had been installed. To assist in this, a method to assess airborne exposure to herring allergen was needed. METHODS: Exposure to airborne herring antigen, mould spores, and endotoxin were measured during work. Antigen exposure was assessed using a newly developed sensitive (detection limit, 0.1 ng ml(-1)) rabbit polyclonal sandwich enzyme-linked immunosorbent assay against the major herring muscle protein allergen, parvalbumin. Aerosols were measured by mass concentration (DataRAM) and number of particles (Climet I-500). RESULTS: Personal geometric mean herring allergen exposure was 986 ng m(-3) at the old filleting workstations and 725 ng m(-3) at the new workstations (difference not significant). Outside the production room, the level was ~130 ng m(-3). Number of particles and mass concentration were both significantly lower around the new machines than around the old machines (P < 0.001 and P < 0.0001, respectively). The highest particle count was seen for the 0.3-0.5 µm fraction, with more than 400,000 particles per cubic metre air. Endotoxin concentration in the air varied between 3 and 92 EU m(-3), with the highest levels when the catch mainly contained herring that had eaten krill or seaweed. CONCLUSIONS: We developed a sensitive method to detect herring antigen. High exposure to herring antigen was measured during filleting work. The particles in the air around the fillet machines were mainly <0.5 µm and the newer encapsulated machines generated fewer particles. It is important to reduce occupational exposure of workers to aerosols by improving the ventilation system, machines, and organization of work.


Assuntos
Poluentes Ocupacionais do Ar/análise , Alérgenos/análise , Exposição por Inalação/análise , Exposição Ocupacional/análise , Parvalbuminas/análise , Aerossóis , Alérgenos/imunologia , Animais , Asma Ocupacional/epidemiologia , Asma Ocupacional/etiologia , Asma Ocupacional/imunologia , Peixes , Indústria de Processamento de Alimentos , Humanos , Exposição por Inalação/efeitos adversos , Exposição Ocupacional/efeitos adversos , Parvalbuminas/imunologia , Sistema Respiratório
6.
Zootaxa ; 3721: 488-94, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-26120688

RESUMO

The third instar larva of Distoleon annulatus (Klug, 1834) is described for the first time and compared with the larva of the other known species of the genus in Europe: D. tetragrammicus (Fabricius, 1798). Diagnostic characters of the larvae of the genus Distoleon, as well as the interspecific differences, are provided and illustrated. Larvae of Distoleon appear to be morphologically conservative and they are mainly recognized by means of the pigmentation pattern.


Assuntos
Insetos/classificação , Larva/crescimento & desenvolvimento , Estruturas Animais/anatomia & histologia , Estruturas Animais/crescimento & desenvolvimento , Animais , Tamanho Corporal , Europa (Continente) , Feminino , Insetos/anatomia & histologia , Insetos/crescimento & desenvolvimento , Larva/anatomia & histologia , Larva/classificação , Masculino
7.
J Surg Case Rep ; 2023(1): rjac616, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36636655

RESUMO

Tessier no. 7 clefts are characterized by macrostomia, facial muscular diastasis and maxillary and zygomatic bone abnormalities. It is caused by a lack of ectomesenchyme formation or penetration of the maxillary and mandibular processes during the fourth and fifth weeks of development. A case of bilateral transverse facial cleft with an accessory maxilla and an osseous choristoma is presented. The diagnosis of accessory maxilla was based on clinical findings due to the inaccessibility of orthopantomography and computed tomography scan. Orbicularis oris muscle reconstruction, cheiloplasty and excision of accessory maxilla were done. Histopathological examination of the bony lesion showed an osseous choristoma. There were no postoperative complications or local recurrence of the lesion excised. This case report demonstrates the importance of early diagnosis and intervention in maxillofacial congenital anomalies. Cheiloplasty restores function and gives the patient a natural appearance. The excision of accessory bone prevents further complications in the child's growth.

8.
J Surg Case Rep ; 2023(5): rjad275, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37220593

RESUMO

Mesenteric cysts are uncommon intra-abdominal lesions that account for only one in every 100 000 adult hospitalizations. Their diagnosis is based on a comprehensive clinical examination as well as radiological modalities such as ultrasonography and computed tomography (CT) scans, and it is usually a clinical challenge because of non-specific symptoms. We present our first case of a 51-year-old man with a simple mesenteric cyst accompanying acute appendicitis diagnosed by CT scan of the abdomen and treated by exploratory laparotomy, complete enucleation of the cyst and appendectomy with a 10 month follow-up without complications or recurrence. This type of presentation has not been thoroughly investigated, with only two children reported during our literature review. Even if there is a high level of suspicion, a CT scan is required for confirmation.

9.
J Surg Case Rep ; 2022(11): rjac546, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36452280

RESUMO

The incidence of the Pfannenstiel incisional hernia (IH) is the lowest of all IHs, it can occur due to patient-related factors or faulty technique in closure of the deeper layer. The use of prosthetic mesh repair is heralding a new era of tension-free herniorrhaphy, while the optimal location for its implantation remains controversial. As a result, no strategy or technique has become the gold standard for its repair. We report our first experience with an IH through Pfannenstiel in a 49-year-old obese female patient. Inlay polypropylene open mesh repair was performed. As the only complication, the patient presented with a seroma in the wound, which was aspirated, and she is currently asymptomatic with outpatient consultation follow-up. Pfannenstiel IHs have received minimal attention on the optimal surgical approach and postoperative results, making this case a good starting point for future studies.

10.
J Surg Case Rep ; 2021(11): rjab481, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34858574

RESUMO

Cervical necrotizing fasciitis represents an aggressive form of deep neck space infection with a high mortality rate. The origin is generally odontogenic, in most cases, resulting from a dental abscess. A series of three cases developed after local application of herbal medicine in patients with no co-morbidities and with a history of a toothache in the lower quadrants for >2 weeks is presented. All patients were managed with antibiotics, extraction of offending tooth and serial wound debridement. Two patients recovered with a resultant skin defect on the neck and one died due to multiple organ failure. This case series demonstrated that early diagnosis, prompt surgical intervention and appropriate medical treatment are very important to increase patient survival. Late report to hospital because of financial constraints and over-reliance on herbal preparation could lead to the development of serious complication in patients with dental infections and could even lead to death of the patient.

11.
J Biotechnol ; 139(1): 95-101, 2009 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-18984020

RESUMO

The grapevine genetic transformation programs have relayed on the use of solid media-based somatic embryogenesis. To reach a high throughput of candidate gene evaluation in 'Thompson Seedless', a semi-automatic system allowing viable transformation of explants was designed. An intermediate procedure using liquid media and agitated flasks was first characterized, leading to reduction in the biomass duplication time of pro-embryogenic (PE) cells from 30 d in dishes to 14 d. The oxygen transfer coefficient value in this system was 213h(-1) at 120rpm and 25 degrees C with a 16/8-h (light/darkness) photoperiod. The scaling-up to the air-lift bioreactor decreased the biomass duplication time of PE cells up to 5.3 d post-inoculation (pi) and an average volumetric productivity of 1.6g/(dxL). Although slight browning was seen in the explants during the phase of 8-14 d pi, no losses in their viability and regenerative capability were observed. Cultured cells showed normal elongation in the transition from heart- to the torpedo-shape and finally to advanced developmental stages, with radicle emergence and whole plant generation. Agrobacterium-mediated transformation of cells was efficiently incorporated after this multiplication process by use of conventional procedures in dishes, allowing the generation of transgenic plantlets confirmed by PCR.


Assuntos
Reatores Biológicos , Engenharia Genética/métodos , Plantas Geneticamente Modificadas , Transformação Genética , Vitis/embriologia , Vitis/genética , Análise de Variância , Biomassa , Células Cultivadas , Desenho de Equipamento , Técnicas de Transferência de Genes , Oxigênio/metabolismo , Sacarose/metabolismo , Técnicas de Cultura de Tecidos , Vitis/citologia
12.
Zootaxa ; 4612(3): zootaxa.4612.3.3, 2019 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-31717052

RESUMO

Four new species of Plega Navás, 1928 (Mantispidae: Symphrasinae) from Mexico are herein described and illustrated, namely P. mixteca sp. n. from Oaxaca and Jalisco, P. stangei sp. n. from Morelos and Oaxaca, P. sonorae sp. n. from Sonora, and P. spinosa sp. n. from Guerrero, Jalisco, Morelos, Nayarit, Oaxaca, Puebla, and Veracruz. Including these new species, Plega's diversity raises to 17 described species, of which 12 are recorded from Mexico, and one of them, Plega variegata Navás, 1928, is herein proposed as nomen dubium. A taxonomic key to the known species of Plega from Mexico is provided.


Assuntos
Colubridae , Holometábolos , Animais , México
13.
J Aerosol Med Pulm Drug Deliv ; 31(1): 61-70, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-28768120

RESUMO

BACKGROUND: Preclinical evaluation of new chemical entities (NCEs) designed to be administered by inhalation route requires lung administration to rodents, especially in the discovery phase. Different administration methods have been used until now, but more efforts are required to obtain controlled and reproducible lung deposition when only small amounts of neat powder material are available. METHODS: The PreciseInhale platform used in the present study enables well-controlled powder aerosol exposures with only small amounts of micronized neat material, providing data on inhalation pharmacokinetic (PK) of NCEs at a very early stage. The DustGun aerosol technology uses compressed air to generate a respirable aerosol from milligram-amounts of powder that is delivered to one animal at a time. The new methodology was used to investigate the inhalation PK and lung retention in the rat of the novel Chiesi PDE4 inhibitor CHF6001 in three exposure models of the PreciseInhale platform: nose-only, intratracheally intubated rat, and the isolated, ventilated, and perfused rat lung. Results were compared with data from two other pulmonary delivery systems commonly used in preclinical studies: liquid instillation and powder insufflation. RESULTS: Administration of micronized CHF6001 using the PreciseInhale system yielded lung exposures in the same range as the other tested devices, but the reproducibility in lung deposition was improved. The initial amount of CHF6001 in lungs at the first sampling time point was close to the predetermined target dose. Tracheal deposition with PreciseInhale (0.36 ± 0.22 µg) was significantly less than with other tested delivery systems: PennCentury (23.7 ± 3.2 µg) and Airjet (25.6 ± 7.2 µg). CONCLUSIONS: The PreciseInhale platform enabled the administration of CHF6001 powder with good accuracy and reproducibility, with low tracheal deposition. The new platform can be used at an early discovery stage to obtain inhalatory PK data for respirable aerosols of neat NCE powder without excipients and with minimal use of dry powder formulation work.


Assuntos
Sistemas de Liberação de Medicamentos , Pulmão/metabolismo , Inibidores da Fosfodiesterase 4/farmacocinética , Sulfonamidas/farmacocinética , para-Aminobenzoatos/farmacocinética , Administração por Inalação , Aerossóis , Animais , Avaliação Pré-Clínica de Medicamentos/métodos , Feminino , Masculino , Modelos Biológicos , Inibidores da Fosfodiesterase 4/administração & dosagem , Pós , Ratos , Ratos Sprague-Dawley , Reprodutibilidade dos Testes , Sulfonamidas/administração & dosagem , Tecnologia Farmacêutica/métodos , Distribuição Tecidual , Traqueia/metabolismo , para-Aminobenzoatos/administração & dosagem
14.
Zootaxa ; 4196(2): zootaxa.4196.2.2, 2016 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-27988672

RESUMO

A new antlion (Neuroptera Myrmeleontidae Myrmeleontini), Myrmeleon almohadarum  sp. nov., is described from southern Spain and Tunisia. The new taxon is closely related  to the mostly sympatric M. inconspicuus Rambur and M. mariaemathildae Pantaleoni, Cesaroni & Nicoli Aldini but differing in body pattern, wing venation and larval chaetotaxy. The validity of the new species is also supported by a phylogenetic analysis based on COI sequences. The larva of this new species is described and compared with congeners. M. almohadarum appears to be associated with sandy environments.


Assuntos
Insetos/anatomia & histologia , Insetos/classificação , Animais , Feminino , Insetos/genética , Larva/anatomia & histologia , Masculino , Filogenia , Análise de Sequência de DNA , Espanha , Especificidade da Espécie , Tunísia
15.
Inflammation ; 29(1): 39-45, 2005 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16502345

RESUMO

Exposure in swine confinement buildings induces an intense airway inflammation. Twenty-two volunteers, of whom eleven wore a half-mask, were exposed for 3 hr in a swine barn. Blood samples were drawn before and after exposure. The ratio C3b/totalC3 in plasma decreased from 6.8 to 5.0% (p = 0.02) without mask and from 6.6 to 5.9% (p = 0.01) with mask (p = 0.67 between groups). The ratio Bb/totalB decreased from 14.5 to 13.5% (p < 0.01) without and 14.6-13.3% (p = 0.09) with mask (p = 0.25 between groups). Epithelial cells (A549) incubated up to 24 hr with 0.1 mg/mL dust suspensions were analysed for C3, IL-6 and IL-8 secretion. Cumulative C3 synthesis of dust stimulated cell cultures was 43,000 pg/mL compared to 25,000 pg/mL in unstimulated cells. Cumulative dust-induced IL-6 and IL-8 secretion was 200 and 3000 pg/mL, respectively and below detection in unstimulated cells. The activation of complement in vivo and induced C3 synthesis by epithelial cells suggests a role of complement in the airway reaction to organic dust exposure.


Assuntos
Poluentes Ocupacionais do Ar , Complemento C3/análise , Fator B do Complemento/metabolismo , Poeira , Exposição Ocupacional , Suínos/imunologia , Adulto , Animais , Carcinoma/patologia , Linhagem Celular Tumoral , Complemento C3/metabolismo , Complemento C3b/análise , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Interleucina-6/análise , Interleucina-8/análise , Neoplasias Pulmonares/patologia , Masculino , Pessoa de Meia-Idade
16.
J Biotechnol ; 209: 31-40, 2015 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-26080080

RESUMO

Lactulose and galacto-oligosaccharides (GOS) are well recognized prebiotics derived from lactose. In the synthesis of lactulose with ß-galactosidases GOS are also produced, but the ratio of lactulose and GOS in the product can be tuned at will, depending on the operation conditions, so to obtain an optimal product distribution in terms of prebiotic potential. The selectivity of fermentation of each carbohydrate alone as well as mixtures of both was determined using pH-controlled anaerobic batch cultures with faecal inoculum. Within the experimental range considered, lactulose/GOS molar ratio of 4 resulted in the highest selectivity for Bifidobacterium and Lactobacillus/Enterococcus, so this ratio was selected as the target for the synthesis of lactulose from fructose and lactose with Aspergillus oryzae ß-galactosidase. Synthesis was optimized using response surface methodology, considering temperature, initial concentrations of acceptor sugars and fructose/lactose molar ratio as key variables, with the aim of maximizing lactulose yield at the optimal product distribution in terms of prebiotic potential (lactulose/GOS molar ratio of 4). Under optimal conditions (50°C, 50%w/w total initial concentrations of sugars and fructose/lactose molar ratio of 6.44), lactulose yield of 0.26g of lactulose produced per g of initial lactose was obtained at the optimal product distribution.


Assuntos
Bactérias Anaeróbias/metabolismo , Lactulose/biossíntese , Oligossacarídeos/biossíntese , beta-Galactosidase/metabolismo , Técnicas de Cultura Celular por Lotes , Fezes/microbiologia , Fermentação , Frutose/metabolismo , Galactose/metabolismo , Fármacos Gastrointestinais/metabolismo , Prebióticos
17.
Toxicology ; 185(1-2): 9-16, 2003 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-12505440

RESUMO

We have found that incubation of heparin plasma with Ni(2+) or Co(2+) at concentrations below 100 microM can stimulate the conversion of complement factor C3 to C3b faster than magnesium, which is the natural cofactor in the alternative complement activation. This conversion was monitored by light absorbance measurement after separation by isotachophoresis, immunofixation and protein staining. The generation of C3b stimulated by these metals (<0.5 mM) proceeds up to about four times faster than the stimulation by Mg(2+). Half of total C3 in the incubation media was converted by Ni(2+) or Co(2+) at 0.5 mM after 20 min at 37 degrees C. Increasing Ni(2+) concentrations over 0.5 mM decreased the C3 conversion rate. Activation of C3 stimulated by Ni(2+), Co(2+) and Mg(2+) was concomitant with the conversion of complement factor B to Bb, but complement factor C4 was not affected by the activation. The conversion of B to Bb was monitored after separation by isotachophoresis and immunoblotting. Other divalent metal ions tested, namely Ca(2+), Ba(2+), Cu(2+) and Zn(2+), did not stimulate the complement cascade. We postulate that the increased rate of C3-fragment production induced by nickel or cobalt ions is central for the immunotoxicity of these metals.


Assuntos
Cobalto/farmacologia , Ativação do Complemento , Complemento C3/metabolismo , Magnésio/farmacologia , Níquel/farmacologia , Animais , Relação Dose-Resposta a Droga , Eletroforese em Gel de Ágar , Humanos
18.
Electron. j. biotechnol ; 42: 1-5, Nov. 2019. tab, graf
Artigo em Inglês | LILACS | ID: biblio-1087340

RESUMO

Background: Fermentation strategies for bioethanol production that use flocculating Saccharomyces cerevisiae yeast need to account for the mechanism by which inhibitory compounds, generated in the hydrolysis of lignocellulosic materials, are tolerated and detoxified by a yeast floc. Results: Diffusion coefficients and first-order kinetic bioconversion rate coefficients were measured for three fermentation inhibitory compounds (furfural, hydroxymethylfurfural, and vanillin) in self-aggregated flocs of S. cerevisiae NRRL Y-265. Thièle-type moduli and internal effectiveness factors were obtained by simulating a simple steady-state spherical floc model. Conclusions: The obtained values for the Thiéle moduli and internal effectiveness factors showed that the bioconversion rate of the inhibitory compounds is the dominant phenomenon over mass transfer inside the flocs.


Assuntos
Saccharomyces cerevisiae/metabolismo , Biocombustíveis , Leveduras , Benzaldeídos , Biodegradação Ambiental , Inativação Metabólica , Difusão , Floculação , Furaldeído/análogos & derivados
19.
Zootaxa ; 3835(3): 364-70, 2014 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-25081458

RESUMO

The larva of Tricholeon relictus, a Spanish endemic antlion of Afrotropical affinities, is described and illustrated for the first time also providing a comparison with the only other European member of the tribe Dendroleontini, Dendroleon pantherinus. The larva of this species is synanthropic but probably originally lived in cave-like habitats.


Assuntos
Insetos/classificação , Larva/crescimento & desenvolvimento , Estruturas Animais/anatomia & histologia , Estruturas Animais/crescimento & desenvolvimento , Animais , Tamanho Corporal , Ecossistema , Feminino , Insetos/anatomia & histologia , Insetos/crescimento & desenvolvimento , Larva/anatomia & histologia , Larva/classificação , Tamanho do Órgão
20.
PLoS One ; 9(8): e105993, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25162704

RESUMO

Alginates are polysaccharides used as food additives and encapsulation agents in biotechnology, and their functional properties depend on its molecular weight. In this study, different steady-states in continuous cultures of A. vinelandii were established to determine the effect of the dilution rate (D) and the agitation rate on alginate production and expression of genes involved in alginate polymerization and depolymerization. Both, the agitation and dilution rates, determined the partitioning of the carbon utilization from sucrose into alginate and CO2 under oxygen-limiting conditions. A low D (0.07 h(-1)) and 500 rpm resulted in the highest carbon utilization into alginate (25%). Quantitative real-time polymerase chain reaction was used to determine the transcription level of six genes involved in alginate polymerization and depolymerization. In chemostat cultures at 0.07 h(-1), the gene expression was affected by changes in the agitation rate. By increasing the agitation rate from 400 to 600 rpm, the algE7 gene expression decreased tenfold, whereas alyA1, algL and alyA2 gene expression increased between 1.5 and 2.8 times under similar conditions evaluated. Chemostat at 0.07 h(-1) showed a highest alginate molecular weight (580 kDa) at 500 rpm whereas similar molecular weights (480 kDa) were obtained at 400 and 600 rpm. The highest molecular weight was not explained by changes in the expression of alg8 and alg44 (genes involved in alginate polymerization). Nonetheless, a different expression pattern observed for lyases could explain the highest alginate molecular weight obtained. Overall, the results suggest that the control of alginate molecular weight in A. vinelandii cells growing in continuous mode is determined by a balance between the gene expression of intracellular and extracellular lyases in response to oxygen availability. These findings better our understanding of the biosynthesis of bacterial alginate and help us progress toward obtain tailor-made alginates.


Assuntos
Azotobacter vinelandii/metabolismo , Regulação Bacteriana da Expressão Gênica , Genes Bacterianos , Microbiologia Industrial , Oxigênio/metabolismo , Alginatos , Azotobacter vinelandii/genética , Biomassa , Carbono/metabolismo , Meios de Cultura/química , Fermentação , Ácido Glucurônico/biossíntese , Ácidos Hexurônicos , Peso Molecular , Sacarose/metabolismo
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