Stages of growth

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Postlarval development of Nicolea uspiana (Polychaeta: Terebellidae)

Postlarval development of Nicolea uspiana (Polychaeta: Terebellidae)

ABSTRACT. The postlarval development of Nicolea uspiana (Nogueira, 2003), a small intertidal terebellid polychaete from rocky habitats on the southeastern and southern Brazilian coast, was studied based on postlarval, juvenile and adult specimens. The specimens, ranging from 8 to 43 segments, were collected between May 2006 and May 2007. The youngest postlarval specimen was found crawling outside of the tube. In specimens at different stages of growth, the number of ocelli and tentacles increased; the first pair of nephridial papillae appeared early (before 8-segmented specimen), and the second and third pairs appeared later (31-segmented specimen); the circulatory system only devel- oped when the first pair of branchial bulbs arose (32-segmented specimen), and the second branchial pair appeared later (40-segmented specimen); and the inversion of the uncini positions in some rows occurred in the transition from larva to juvenile (17-segmented specimen). In the course of development, segments 2-3 lost the notochaetae, and segments 3-4 lost the neurochaetae. The changes involved in the development from postlarval to adult animals are illustrated by SEM micrographs and photographs.
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Crop -glucanase activity limits the effectiveness of a recombinant cellulase used to supplement a barley-based feed for free-range broilers

Crop -glucanase activity limits the effectiveness of a recombinant cellulase used to supplement a barley-based feed for free-range broilers

Consumer interest in specialty poultry products derived from free-range or organic production systems has been steadily increasing (Fanatico et al., 2006). Under these systems, animals have access to the outdoors to promote foraging, feed selection and activity, thus improv- ing birds’ general welfare. In Europe, poultry used under these systems may be derived from slow-growing genotypes that are slaughtered at later stages of the growth cycle, generally between weeks 11 and 14 of age. It has been suggested that slow-growing birds are more adapted to less intensive production systems while the quality of their meat is more appropriate for a specialty or gourmet market (Gordon and Charles, 2002). In a recent study we showed that a complex mixture of cellulases and hemicellulases is unable to promote the nutritive value of legume-based pastures used by free-range broilers of a slower-growing genotype (Ponte et al., 2008). Although exogenous plant cell wall hydrolases may not be effective for releasing more energy from plant biomass, it remains to be established if these biocatalysts permit greater incorporation of cereals rich in soluble NSP in the diets of free-range broilers. Specifically, it is still unknown if cellulases and hemicellulases can improve the nutritive value of cereal-based diets for free-range pastured poultry of slower-growing genotypes slaughtered at later stages of growth. In addition, it is well established that individual recombinant enzymes are as efficient as complex enzyme mixtures in decreas- ing the digesta viscosity of broilers of fast- growing genotypes raised under the current intensive production systems that are fed on cereals rich in soluble NSP (Philip et al., 1995; Fontes et al., 2004). However, the possibility of using individual recombinant enzyme to depolymerise the anti-nutritive -glucans found in barley-based diets for free-range broilers of slow-growing genotypes remains to be investigated.
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COTTON RESPONSE TO WATER DEFICITS AT DIFFERENT GROWTH STAGES

COTTON RESPONSE TO WATER DEFICITS AT DIFFERENT GROWTH STAGES

ABSTRACT – Water deficit at certain cotton growth stages can cause severe damage to crop development, affecting physiological processes and reducing reproductive structures, with consequent yield losses. The objective of this study was to evaluate the response of cotton cultivars under water deficit applied at different stages of the crop cycle. We compared the number of bolls per meter, cotton yield, and water use efficiency for eight different cotton cultivars under a water deficit of 15 days. We selected the following growth stages: Emergence (EM), First Square (FS), First Flower (FL), Peak Bloom (PB), and First Open Boll (FOB). The control treatment was irrigated with 100% ETc. The experiment was conducted in Apodi, RN State of Brazil, semiarid region, using a sprinkler irrigation system. The number of bolls per meter, cotton yield, and water use efficiency were influenced by the interaction of cultivars x deficit periods. Lowest values were observed for water suppression in the FL and PB stages. When the water deficit was imposed in the initial stages of growth (EM to FS) or after the FOB stage, the cotton yield reduction was not significant. At the same stage and water deficit, the behavior of the different cultivars was similar. Producers are urged to take this information into account when developing irrigation schemes for cotton crops, thereby avoiding water deficits during the most critical periods of the crop cycle.
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Evaluating Changes In Fertility Status Of An Alfisol Under Different Growth Stages Of Cassava Manihot Esculenta Crantz

Evaluating Changes In Fertility Status Of An Alfisol Under Different Growth Stages Of Cassava Manihot Esculenta Crantz

Akinyemi (2011) and Gliesman (2011) had demonstrated positive and highly significant responses of cassava to fertilizer application, especially during the early stages of growth. Although, cassava derives immense benefits from fertilizer application, nevertheless, for high and sustained productivity, there is a dire need for properly timed fertilizer application in such a way the application will coincide with the most critical stage of growth in cassava, when the demand for nutrients is highest. The most critical stage in vegetative growth phase of cassava, when the demand for nutrients is highest can be determined by monitoring changes in soil nutrient status under different growth stages of cassava. Consequent upon this, a two – year field experiment was designed to appraise changes in nutrient status of an Alfisol under different growth stages of cassava
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Gene expression during oogenesis in the Mozambique tilapia (O. Mossambicus)

Gene expression during oogenesis in the Mozambique tilapia (O. Mossambicus)

Tilapias show a variety of physiological adaptations that allow them to live in different environmental conditions, disturbing local ecosystems where they are introduced by human hand, where they reproduce at faster rates as their cycles are short and constant. They have complex behaviours, with species in the Oreochromis and Sarotherodon genus exhibiting parental care. Thus, they have become a preferred research species. Knowledge on their physiology might benefit the medical sciences, the fisheries industry, environmentsl sciences and aquaculture, which is still the major player in sex genes research, as tilapias fish are the second most cultured species worldwide and there are problems with their high spawning rates as these originate high density stocks in tanks. There is considerable information concerning the hypothalamus-pituitary-gonadal axis in vertebrates, with gonadotrophins (FSH and LH) playing stimulating roles in development of the ovary and maturation of oocytes. Other hormones and factors are involved, mediating the actions of these or as products of their induction. The early stages of development of the ovarian follicle and the enveloped oocytes are still poorly described, with FSH being considered the first inducer for decades. This implies a role for local factors that are regulating the early stages of growth. Recently, TGF-β family member activin has been shown to induce FSH incorporation by the follicles and other members of this family also seem to have an important role in the ovary, such as BMPs and GDFs. Some other factors were studied in this thesis for expression patterns throughout oocyte development. With this objective, ovaries from 8 females were extracted and dissected under a binocular amplifier with groups of oocytes in 4 different stages being collected for each. RNA was extracted and purified and turned into cDNA by reverse transcription. Genes with preferential expression in ovary (determined by subtractive hybridization and then with semi- quantitative RT-PCR) were tested by RT-PCR in oocytes and band intensity was quantified using Quantity One from Biorad, using as reference 18S rRNA. These genes include FoxL2, CYP19a, Vasa, RBMX, BMP-R IB, CPI-17, Aly and other unidentified fragments: SART, PPMP (homolog sequences but not confirmed) and XP2 (putative new protein) and clone 26 (no homolog sequence known). Results show significant differences among the 4 oocyte stages for practically every gene tested, except for Aly and SART. Correlations among some of the genes also show they might have related functions in the process.
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Differential Expression of Notch Signaling-related Transcripts Accompanies Pro-thymocyte Proliferation and Phenotype Transition Induced by Epidermal Growth Factor plus Insulin in Fetal Thymus Organ Cultures

Differential Expression of Notch Signaling-related Transcripts Accompanies Pro-thymocyte Proliferation and Phenotype Transition Induced by Epidermal Growth Factor plus Insulin in Fetal Thymus Organ Cultures

RPA assessment of differential expression of death- related transcripts in EGF- and EGF+INS-FTOCs - Pro- liferation and rescue from death are hardly unraveled pro- cesses in the thymus, sometimes sharing signal trans- ducers, as is the case of FADD (Newton et al. 2000). We thus investigated the expression of death-related tran- scripts, some of which are developmentally regulated in this organ (Chao & Korsmeyer 1998, Tomayko et al. 1999, Newton et al. 2000). We used RPA with probe sets that cover both pro- and anti-apoptotic factors associated with Bcl-family- and TNFR-family-related signaling. If normal- ized for loading on the basis of constitutively expressed transcripts (G3PDH and L32), similar patterns of expres- sion were seen in both EGF- and EGF+INS- transcripts, including those for FADD (Fig. 1). Low levels of signal for Fas were present in these RNAs, when compared to Con- trol-FTOC-derived RNAs (Fig. 1A), consistent with Fas expression being restricted, among immature subsets, to DP cells (Newton et al. 2000). The overall ratio of Bcl- family death antagonists to agonists, which determines the susceptibility to death stimuli (Chao & Korsmeyer 1998), was also maintained in EGF- and EGF+INS- derived transcripts (Fig. 1B).
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Variable Responses to Carbon Utilization between Planktonic and Biofilm Cells of a Human Carrier Strain of Salmonella enterica Serovar Typhi.

Variable Responses to Carbon Utilization between Planktonic and Biofilm Cells of a Human Carrier Strain of Salmonella enterica Serovar Typhi.

strain would serve as a good model for this study to explore the adaptive mech- anism of S. Typhi in two different physiology states, biofilm and planktonic. Furthermore, the ability of S. Typhi to survive outside the human host that remains largely unclear, would be in- vestigated. In this study, differential carbon catabolism of the strain in planktonic and biofilm stages was measured using the high-throughput Biolog Phenotype MicroArray (PM) and Mini- mum Biofilm Eradication Concentration (MBEC) biofilm inoculator (96-well peg lid) [8]. Met- abolic activity was measured by detecting a color change in the tetrazolium dye when there is bacterial respiration in each well. The described method can easily be performed and it pro- vides important insights into the metabolic properties of S. Typhi in planktonic and biofilm cells, as well as carbon substrates that induce the biofilm formation. PM technology has been reported to be used in many studies to reveal metabolic properties of various bacteria [9–13]. However, studies describing the metabolic activity of bacterial biofilms are limited [14]. The objectives of this work were to (i) determine the differences in carbon catabolism of a human carrier S. Typhi strain during planktonic and biofilm state; and (ii) identify the specific carbon substrates that will induce the transition of planktonic cells to form biofilm.
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Effect of Post-Infiltration Soil Aeration at Different Growth Stages on Growth and Fruit Quality of Drip-Irrigated Potted Tomato Plants (Solanum lycopersicum).

Effect of Post-Infiltration Soil Aeration at Different Growth Stages on Growth and Fruit Quality of Drip-Irrigated Potted Tomato Plants (Solanum lycopersicum).

No previous study had specifically examined the response of sub-surface drip-irrigated pot- ted tomato plants at different growth stages to post-infiltration soil aeration. Increasing levels of drip irrigation at a given frequency would supply more soil water available for transpiration, and generally this would increase growth and yield. On the other hand increasing drip-irriga- tion levels also result in lower levels post-infiltration soil aeration. Rawls et al.[34] reported a geometric mean bubbling pressure of 33 for 689 samples silty clay loam soils. Since there was 22.5 cm depth of soil in the pots, it would be expected that there would be little tendency for gravitational drainage from the pots, and that the soil in the vicinity of the sub-surface drip emitters would be close to saturation immediately after irrigation. Since redistribution in finer textured soils is generally slow, this saturated zone would be expected to persist for some time after irrigation. This extent of this zone would also increase with increasing irrigation volumes required to compensate for consumptive use by the plants over time, and maintain the target volumetric soil water content. Any positive effect of post-infiltration aeration would be related primarily on how well the injected air stream permeates this zone and promotes enhanced root activity and overall plant growth and development.
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Single-cell census of mechanosensitive channels in living bacteria.

Single-cell census of mechanosensitive channels in living bacteria.

culturing conditions. In this work we describe these changes quantitatively by determining the Fano factor empirically from the distributions and by fitting a gamma distribution to the histograms of MscL monomers at the single cell level (red curves of Figure 4 and parameters listed in Table S2). The gamma distribution is derived from a model which assumes: the mRNA expression level is determined by a single-state, unregulated promoter; the proteins are expressed in translational bursts from a single copy of mRNA; the number of proteins per burst event is described by an exponential distribution; and the translation events are uncorre- lated in time. There is no transcriptional ‘‘feedback’’ such as auto- regulation or regulation by another gene. The rate of translation is a constant. This distribution accurately describes the measured expression levels of a few simple model genetic circuits in E. coli [46,47]. For low stress conditions (exponential phase and/or media without supplemented salt), the gamma distribution represent the data well. In stationary phase, when significant regulation by RpoS occurs, or in the presence of salt, when osmotic induction occurs, the gamma distribution does not provide a good fit for our data. This suggests that a simple single-promoter state model of transcription [35] may not be adequate to quantitatively describe the observed increase in MscL expression under these conditions. We must bear in mind that the conditions leading to the derivation of model distributions make specific assumptions about both transcription and translation that may not be satisfied in the context of these genes. For example, distributions more complicated than the gamma distribution can arise when there is a multiple-state promoter or multiple promoters involved [48]. Further, the regulatory behavior of RpoS introduces another layer of complexity not considered in these models. It may not even be possible to distinguish between different biophysical models solely on the basis of fitting calculated distributions to measured steady-state protein distributions [49]. As a result, it is really only as a point of departure that we make preliminary fits to our data in terms of gamma distributions, knowing full well that the situation can be (and is) more complicated. In many ways, our thinking is analogous to that used when Hill functions are used to fit binding data since such fits can provide a convenient summary of large quantities of data [50] without necessarily reflecting any underlying mechanistic picture of the binding process.
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Development and optimization of production and purification of the human protein BMP-2 in Escherichia coli for biomedical applications

Development and optimization of production and purification of the human protein BMP-2 in Escherichia coli for biomedical applications

IMAC separates proteins on the basis of a reversible interaction between target protein through histidine residues (or Trp and Cys) present on their surface and divalent metal ions (e.g., Ni 2+ , Cu 2+ , Zn 2+ , Co 2+ ) immobilized via a chelating ligand. In the particular case of this study, nickel was used as immobilized ligand, which allows the affinity of histidines tail present in FH8BMP-2 protein. Immobilized metal ion Affinity Chromatography with nickel (IMAC-Ni) purification experiments involves the following steps: equilibration of the column with binding buffer containing a low concentration of imidazole, which is a counter ligand that binds to the immobilized nickel. Then sample is applied to the column, but before is adjusted to the same imidazole concentration; in this stage, proteins with histidines bind while displacing the imidazole counter ligands. The third step is column wash and then elution of the target protein using a higher concentration of imidazole. Instead of imidazole gradient, it is important to note that these experiments can also be performed using a pH gradient. Final step corresponds to column regeneration, when all molecules that still remained are removed.
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Reproduction of the flatfish Achirus lineatus (Pleuronectiformes: Achiridae) in Paranaguá Bay, state of Paraná, a subtropical region of Brazil

Reproduction of the flatfish Achirus lineatus (Pleuronectiformes: Achiridae) in Paranaguá Bay, state of Paraná, a subtropical region of Brazil

The size of individuals was assessed through the varia- tions in the means for total length (Lt) and total weight (Wt) of individuals (grouped sexes). The seasons of the year were taken as the treatments, and the individuals the replicates; thus, a parametric analysis of variance (ANOVA) was applied, fol- lowed by Tukey’s post hoc test, in order to identify which means differed throughout the year. In order for the ANOVA to be applied, the assumptions of normality and homogeneity of the variances were verified through the Shapiro-Wilk test and the Levene test, respectively (Q UINN & K EOUGH 2002).
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Feeding habits of Carabidae (Coleoptera) associated with herbaceous plants and the phenology of coloured cotton

Feeding habits of Carabidae (Coleoptera) associated with herbaceous plants and the phenology of coloured cotton

Flowering herbaceous plants and weed plants were grown along the edges (1 × 10 m) of the cotton area (Figure 1). The following flowering herbaceous plants (FHPs) were included: sweet alyssum (Lobularia maritima (L.) (Brassicaceae)), marigold (Tagetes erecta L. (Asteraceae)), and buckwheat (Fagopyrum esculentum Moench (Polygonaceae)). One of the edges was formed by weed plants: Amaranthus retroflexus L., Alternanthera tenella Colla and Amaranthus spinosus L. (Amaranthaceae); Sida spinosa L. (Malvaceae); Digitaria insularis (L.), Eleusine indica (L.) Gaer and Cenchrus echinatus L. (Poaceae); Acanthospermum hispidum DC. (Asteraceae); Portulaca oleracea L. (Portulacaceae); Richardia brasiliensis Gomes (Rubiaceae); Euphorbia heterophylla L. and Chamaesyce hyssopifolia (L.) Small (Euphorbiaceae); Commelina benghalensis L. (Commelinaceae); Indigofera hirsuta L. (Fabaceae); and Ipomea grandifolia (Dammer) O'Donell (Convolvulaceae). The FHP species were planted using seedlings or seeds, and they were allowed to grow for a period of time to match the phase of flowering of these plants with the beginning of sampling of carabids on cotton.
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Dental Press J. Orthod.  vol.16 número5 en a15v16n5

Dental Press J. Orthod. vol.16 número5 en a15v16n5

Objective: The aim of this paper is to emphasize the organization of the information avail- able in exams and along the orthodontics treatment of growing individuals, which are used as guidance to predict the pubertal growth spurt. Conclusion: Such information provide op- portunities to increment the diagnosis and prognosis of these cases and in making planning decisions, treatment evolution and the retention phase, mainly for those patients presenting malocclusions associated to skeletal disharmonies.

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MELHORAMENTO POR HAPLODIPLOIDIZAÇÃO ANDROGENÉTICA:VARIAÇÃO GENOTÍPICA NO TAMANHO DAS ANTERAS E NO ESTÁGIO DE DESENVOLVIMENTO DOS MICRÓSPOROS EM AVEIA

MELHORAMENTO POR HAPLODIPLOIDIZAÇÃO ANDROGENÉTICA:VARIAÇÃO GENOTÍPICA NO TAMANHO DAS ANTERAS E NO ESTÁGIO DE DESENVOLVIMENTO DOS MICRÓSPOROS EM AVEIA

ABSTRACT: Oat (Avena spp.) is poorly responsive to the haplodiploidization process, which leads to the production of homozygous lines in one step, increasing breeding efficiency. Androgenetic haploids in small grain cereal crops are obtained from microspores cultured at the mononucleate stage, which can be identified by the size of anthers. In order to identify the appropriate anther size for in vitro culture, microspore cytological analyses were made in Avena sativa cultivars UPF 7, UPF 18, UFRGS 14, Stout and Avena sterilis CAV 3361, cultivated in growth chamber under controlled light and temperature conditions. Variation was observed within and among genotypes for anther size at each microspore developmental stage and according to the position of spikelets in the panicle. Architecture variation in panicle shape and non-linear microsporogenesis maturation increased the challenge of identifying potentially androgenetic oat anthers. Cytological screening before culture is critical in identifying microspores at the right stage for oat androgenesis.
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RELATIONSHIPS BETWEEN GRAIN YIELD AND ACCUMULATION OF BIOMASS, NITROGEN AND PHOSPHORUS IN COMMON BEAN CULTIVARS

RELATIONSHIPS BETWEEN GRAIN YIELD AND ACCUMULATION OF BIOMASS, NITROGEN AND PHOSPHORUS IN COMMON BEAN CULTIVARS

and nutrient accumulation after pod setting was related with a lower grain yield and amounts of N and P in grains (Figure 3). Westermann et al. (1985) also observed that two bean lines with similar patterns of growth and N accumulation during vegetative development had distinct final grain yields. The high N requirement of bean seed induces N remobilization from vegetative tissues, and a concomitant degradation of leaf proteins inducing leaf senescence that results in declined canopy photosynthesis (Lynch & White, 1992). Evidence of a positive relation between the length of the pod filling period, that could provide larger amounts of photosynthates for growing seeds, and grain yield on common bean, suggests that extended leaf area duration would be required for high- yielding bean cultivars (Ranalli & Cubero, 1997). This indicates that grain yield of common bean is not intrinsically associated with the vegetative vigor at flowering, and that some mechanisms during early pod filling can strongly influence the final crop yield. The continuous acquisition of N and P during later growth stages most likely plays a key role in improving grain yield of common bean.
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Functional studies on BolA and related genes:

Functional studies on BolA and related genes:

37 complement to control width and linear axis dimensions respectively, MreB is alone in its task to maintain cell shape determination in E. coli (Jones et al., 2001). MreB protein requires the membrane and periplasmic dimer MreC, the integral membrane MreD and RodA proteins (but not PBP2) to localize correctly (Esue et al., 2005; Karczmarek et al., 2007; Kruse et al., 2005; van den Ent et al., 2001; van den Ent et al., 2006). Moreover MreB as Mlc actively segregate the chromosomes (Kruse et al., 2003), eventually through the interaction with SetB (a sugar membrane transport protein) (Espeli et al., 2003; Liu JY, 1999), localizing origins of replication towards opposite cell halves (Gitai Z, 2004 ; Soufo and Graumann, 2003) [like ParM which requires ATP and is regulated by ParR (Moller-Jensen et al., 2002; Moller-Jensen et al., 2003)] and generate cell polarity by spacially arranging polar proteins (Gitai Z, 2004 ). MreB seems to achieve equal cell partition by duplication and segregation to opposite poles of a doublet ring structure formed in both halves of dividing cells in a previous and independent even of cytokinesis(Vats and Rothfield, 2007). MreB seems to be recruited to induce proper placement of the murein biosynthetic machinery and may be transiently assembled or work as a permanent scaffold for elongation (Osborn and Rothfield, 2007). Finally, crescentin is a recently studied intermediate filaments-like bacterial protein that polymerizes into 10nm thick filaments, specifically localizes in the concave faced cytoplasm of Caulobacter (Ausmees, 2006).
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Basal Salt Requirements Differ According to Culture Stage and Cultivar in Date Palm Somatic Embryogenesis

Basal Salt Requirements Differ According to Culture Stage and Cultivar in Date Palm Somatic Embryogenesis

The current study demonstrated that the response of different genotypes to different formulations varies, indicating an interaction between medium formulation and genotype. The phenomenon of genotype dependency in response to in vitro date palm manipulations is well documented in various plant species (Karami, 2008; Shirani et al., 2010) as well as date palm (Al-Khayri and Al-Bahrany, 2004). The results have shown that the effect of basal media formulations can be influenced by various date palm genotypes. Analogous to this finding, several investigations have shown variable responses of different cultivars to different media formulations in a number of plant species (Khanna and Raina, 1998; Perez-Tomero and Burgos, 2000; Khatun et al., 2003). In oil palm (Elaeis guineensis Jacq.), the highest embryogenic callus formation from zygotic embryo explants, somatic embryogenesis and germination were achieved using N6 medium as compared to MS medium (Thuzar et al., 2010). However, other cultivars of oil palm exhibited the best responses using Y3 medium as compared to N6 and MS media (Muniran et al., 2008). Rafiq et al. (2005) observed interactions between media and different maize (Zea mays L.) genotypes in a study involving callus induction and plant regeneration using various media formulations including MS, LS, B5 and N6. Gonzalez et al. (2001) demonstrated a strong influence of genotype on callus induction and plant regeneration from immature embryos of durum wheat
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Mat. Res.  vol.8 número2

Mat. Res. vol.8 número2

There are few bubbles on the unphosphated magnet surface im- mediately after immersion. After 15 seconds, H 2 bubbles completely covered the surface of the unphosphated magnet, suggesting fast kinetics of nucleation and growth on the surface. The phosphated magnets showed different behavior depending on phosphating con- ditions. The specimen phosphated in solution A for 4 hours showed bubbles on its surfaces after only 15 seconds of immersion and fast growth kinetics from that time onwards. The magnets phosphated in solution A for 18 hours demonstrated the best corrosion perform- ance among all the specimens that were tested. On these specimens, only a few bubbles nucleated on its surface after 120 seconds of im- mersion in the acid solution. Phosphating in molybdate containing solution (solution B), resulted in improved corrosion resistance of the magnet surfaces compared to unphosphated specimens, but the increase in phosphating time in this solution was not as effective as that in the solution without molybdate. A comparison of the magnet
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Screening a bacterium and its effect on the biological degumming of

Screening a bacterium and its effect on the biological degumming of

ABSTRACT: Biological degumming is an eco-friendly, efficient, high-quality and low-cost method that has become the leading bast fiber degumming technology. However, bacterial strains with short degumming cycles, high gum removal rates and small fiber damage are few. To screen high quality microbial resources with bast-fiber biological degumming function, soil samples were collected from a continuously cultivated banana plantation and then used to be enriched by ramie and kenaf materials in turn. A selective pectin-degrading medium was used to screen for excellent bacteria. A dominant bacterial strain was identified by phenotypic and genotypic characteristics, and its biological degumming effects on ramie and kenaf were verified by a com- prehensive evaluation system. Results showed that seven bacterial strains secreting pectinase were obtained and the largest hydrolysis circle with a diameter ratio H/C of 2.4 was produced by the bacterial strain hn1-1, which was preliminarily identified as the Bacillus cereus by colony mor- phological characteristics and 16S rDNA sequence (GenBank accession number: KX013542) cluster analysis. The fiber production of ramie and kenaf degummed by B. cereus hn1-1 for 10 h were 72 % and 76 %, the residual gum rates were 4 % and 5 %, respectively. These values satisfied the textile industry requirement of < 6 % residual gum rate. Therefore, an effective biological degumming bacterium, B. cereus, was identified using a pectin-hydrolysis selective medium through a simple, economical, and time-saving method. Furthermore, the biological degumming technology by B. cereus for ramie and kenaf had a short cycle, ideal removal gum rate, and high-quality and productive fiber output.
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A high speed detection platform based on surface-enhanced Raman scattering for monitoring antibiotic-induced chemical changes in bacteria cell wall.

A high speed detection platform based on surface-enhanced Raman scattering for monitoring antibiotic-induced chemical changes in bacteria cell wall.

We report here a new diagnostic platform that reveals chemical features associated with the bacterial envelope. Using the cell wall SERS spectra as fingerprints for individual bacteria, this system can potentially differentiate known or even unknown microbes. However, although some bacteria, such as S. aureus and E. coli, do possess hallmark SERS spectra for species identification, there are bacteria whose SERS profiles significantly overlap such that this hinders differential diagnosis. Furthermore, at the subspecies level, although certain strains of Klebsiella pneumoniae are distinguishable by SERS due mainly to variation in capsule formation (data not shown), the current SERS detection method alone cannot unequivocally tell, within this bacterial species, one strain from another. Further improvements in data analysis might enhance the differentiation power; however, we do realize that compared to genome sequencing, PCR reactions or even mass spectrometry- based proteomics analysis, the SERS spectra described here lack the specificity at a molecular level that will allow the definitive assigning of bacterial identity. Nevertheless, taking advantages of the new method’s convenience, rapidity, stability and especially its high sensitivity, we demonstrate here several novel applications and functional tests that cannot be easily achieved by other platforms. Specifically, we found that the microbes’ proliferation state and its susceptibility to antibiotics can be rapidly uncovered by studying the dynamic changes that occur in the SERS profiles in live bacteria. Since SERS detection is based on revealing the ‘‘chemical features’’ of the bacterial envelope rather than by monitoring the progress of a biological event, such as division, the SERS method is especially useful for the analysis of slow-growing bacteria, which typically may take weeks during laboratory tests.
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