The interaction of water flow and nutrients on aquatic plant growth

A long-term experiment was conducted to compare the effects of flowing and still water on growth, and the relationship between water flow and nutrients, in Aponogeton elongatus, a submerged aquatic macrophyte. A. elongatus plants were grown for 23 weeks with three levels of nutrition (0, 0.5 and 1g Osmocote Plus(R) fertiliser pot(-1)) in aquaria containing stirred or unstirred water. Fertilized plants grew much better than non-fertilized. The highest fertilizer level produced 29% wider leaves and 58% higher total dry weight in stirred water. Stirred water increased leaf area by 40% and tuber size by 81%, but only with the highest level of nutrition. These results suggest that this plant depends on its roots for mineral uptake, rather than from the open water, and the major limitation to growth in still water is the supply of dissolved inorganic carbon. It was the combined effects of nutrient availability and stirring that produced the strongest response in plant growth, morphology and composition. This study provides some explanation for the observations of others that these plants grow best in creeks or river systems with permanently flowing water.

Provision of 4-1BB ligand enhances effector and memory CTL responses generated by immunization with dendritic cells expressing a human tumor-associated antigen

Up-regulation of receptor-ligand pairs during interaction of an MHC-presented epitope on dendritic cells (DCs) with cognate TCR may amplify, sustain, and drive diversity in the ensuing T cell immune response. Members of the TNF ligand superfamily and the TNFR superfamily contribute to this costimulatory molecule signaling. In this study, we used replication deficient adenoviruses to introduce a model tumor-associated Ag (the E7 oncoprotein of human papillomavirus 16) and the T cell costimulatory molecule 4-IBBL into murine DCs, and monitored the ability of these recombinant DO to elicit E7-directed T cell responses following immunization. Splenocytes from mice immunized with DCs expressing E7 alone elicited E7-directed effector and memory CTL responses. Coexpression of 4-1BBL in these E7-expressing DO increased effector and memory CTL responses when they were used for immunization. 4-1BBL expression up-regulated CD80 and CD86 second signaling molecules in DO. We also report an additive effect of 4-IBBL and receptor activator of NF-kappaB/receptor activator of NF-kappaB ligand coexpression in E7-transduced DC inummogens on E7-directed effector and memory CTL responses and on MHC class II and CD80/86 expression in DCs. Additionally, expression of 4-1BBL in E7-transduced DCs reduced nonspecific T cell activation characteristic of adenovirus vector-associated immunization. The results have generic implications for improved or tumor Ag-expressing DC vaccines by incorporation of exogenous 4-1BBL. There are also specific implications for an improved DC-based vaccine for human papillomavirus 16-associated cervical carcinoma.

Radio frequency plasma-induced hydrogen bonding on kaolinite

The radio frequency (RF) plasma-modified surfaces of kaolinite were investigated by diffuse reflectance infrared Fourier transform spectroscopy (DRIFT) and deuteration techniques to determine the nature of RF plasma-induced surface functional groups, the altered sites in the lattice, and interaction mechanism between RF plasma and the surface of the kaolinite. It has been concluded that the RF plasma-induced infrared (IR) vibration absorption bands at 2805, 3010, and 3100 cm(-1) are attributable to the stretching vibration of hydrogen-bonded hydroxyl groups, and the band at 1407 cm(-1) is attributable to the bending vibration of (HO-)Al-O or (HO-)Si-O groupings with hydrogen-bonded hydroxyl groups. Structural alteration occurred on both the surface and subsurface region of the kaolinite during RF plasma treatment. Further structural alteration or adjustment was also observed on well-modified and well-deuterated kaolinite. There are two types of OD bands visible in the DRIFT spectra of this kaolinite, one type which decreased rapidly as a function of time in moist air, and the other which remained unchanged during the measurement. Furthermore, the appearance of broad IR bands at 3500-3100 cm(-1) as a result of deuteration is evidence of structural disturbance by RF plasma treatment lattice deuteration. An RF plasma-induced hydrogen bonding model on the surface of the kaolinite is proposed.

Interaction of directional, neuromuscular and egocentric constraints on the stability of preferred bimanual coordination patterns

We investigated how the relative direction of limb movements in external space (iso- and non-isodirectionality), muscular constraints (the relative timing of homologous muscle activation) and the egocentric frame of reference (moving simultaneously toward/away the longitudinal axis of the body) contribute to the stability of coordinated movements. In the first experiment, we attempted to determine the respective stability of isodirectional and non-isodirectional movements in between-persons coordination. In a second experiment, we determined the effect of the relative direction in external space, and of muscular constraints, on pattern stability during a within-person bimanual coordination task. In the third experiment we dissociated the effects on pattern stability of the muscular constraints, relative direction and egocentric frame of reference. The results showed that (1) simultaneous activation of homologous muscles resulted in more stable performance than simultaneous activation of non-homologous muscles during within-subject coordination, and that (2) isodirectional movements were more stable than non-isodirectional movements during between-persons coordination, confirming the role of the relative direction of the moving limbs in the stability of bimanual coordination. Moreover, the egocentric constraint was to some extent found distinguishable from the effect of the relative direction of the moving limbs in external space, and from the effect of the relative timing of muscle activation. In summary, the present study showed that relative direction of the moving limbs in external space and muscular constraints may interact either to stabilize or destabilize coordination patterns. (C) 2003 Published by Elsevier B.V.

Model studies on the role of citrate, malate and pectin esterification on the enzymatic degradation of Al- and Ca-pectate gels: possible implications for Al-tolerance

Aluminium (At) tolerance in plants may be conferred by reduced binding of Al in the cell wall through low root cation exchange capacity (CEC) or by organic acid exudation. Root CEC is related to the degree of esterification (DE) of pectin in the cell wall, and pectin hydrolysis plays a role in cell expansion. Therefore, it was hypothesised that Al-tolerant plants with a low root CEC maintain pectin hydrolysis in the presence of Al, allowing cell expansion to continue. Irrespective of the DE, binding of Al to pectin reduced the enzymatic hydrolysis of Al-pectin gels by polygalacturonase (E.C. 3.2.1.15). Pectin gels with calcium (Ca) were slightly hydrolysed by polygalacturonase. It was concluded, therefore, that Al tolerance conferred by low root CEC is not mediated by the ability to maintain pectin hydrolysis. Citrate and malate, but not acetate, effectively dissolved Al-pectate gel and led to hydrolysis of the dissolved pectin by polygalacturonase. The organic acids did not dissolve Ca-pectate, nor did they increase pectin hydrolysis by polygalacturonase. It was concluded that exudation of some organic acids can remove Al bound to pectin and this could alleviate toxicity, constituting a tolerance mechanism. (C) 2003 Editions scientitiques et medicales Elsevier SAS. All rights reserved.

Recombinant expression of Munc18c in a baculovirus system and interaction with syntaxin4

Two protein families that are critical for vesicle transport are the Syntaxin and Munc18/Sec1. families of proteins. These two molecules form a high affinity complex and play an essential role in vesicle docking and fusion. Munc18c was expressed as an N-terminally His-tagged fusion protein from recombinant baculovirus in Sf9 insect cells. His-tagged Munc18c was purified to homogeneity using both cobalt-chelating affinity chromatography and gel filtration chromatography. With this simple two-step protocol, 3.5 mg of purified Munc18c was obtained from a 1 L culture. Further, the N-terminal His-tag could be removed by thrombin cleavage while the tagged protein was bound to metal affinity resin. Recombinant Munc18c produced in this way is functional, in that it forms a stable complex with the SNARE interacting partner, syntaxin4. Thus we have developed a method for producing and purifying large amounts of functional Munc18c-both tagged and detagged-from a baculovirus expression system. We have also developed a method to purify the Munc18c:syntaxin4 complex. These methods will be employed for future functional and structural studies. Crown copyright (C) 2003 Published by Elsevier Inc. All rights reserved.

Agroamigo

No Nordeste, a agricultura familiar representa 82,9% da ocupa????o de m??o de obra no campo. O Banco do Nordeste desenvolveu o Agroamigo, uma inova????o em metodologia de concess??o de cr??dito para os agricultores familiares de baixa renda. O Agroamigo possibilita aos agricultores serem atendidos em suas pr??prias comunidades, diminuindo os deslocamentos para a ag??ncia, al??m de receberem acompanhamento e orienta????o de um especialista em atividades rurais. Possibilita a educa????o financeira sobre endividamento, planejamento financeiro, poupan??a, melhores formas de alocar recursos, uso correto do cr??dito e a import??ncia do retorno do recurso para o governo federal. O Agroamigo ?? o maior programa de microfinan??as rural do Brasil, tendo recebido reconhecimento nacional e internacional por seu modelo. Por conceder cr??dito de forma gradual e sequencial, tem promovido o desenvolvimento sustent??vel das atividades financiadas e reduziu a inadimpl??ncia de 63,94% para 4,68%

Caixas receptoras de correspond??ncias confeccionadas com material recicl??vel

Os Correios t??m como miss??o facilitar as rela????es pessoais e empresariais mediante a oferta de servi??os de correios com ??tica, competitividade, lucratividade e responsabilidade social. Fundamentada em objetivos estrat??gicos, como o de obter padr??es de qualidade e produtividade requeridos pelas partes interessadas e aumentar a percep????o da sociedade em rela????o ?? atua????o da ECT como empresa socialmente respons??vel, a Ag??ncia de Conchas/DR/SPI implantou a????o socioambiental e educacional com a comunidade: a instala????o de caixas receptoras de correspond??ncia em suas resid??ncias, utilizando materiais recicl??veis. O projeto proporcionou ganhos significativos para a Ag??ncia e para os mun??cipes na presta????o de um servi??o com maior qualidade e agilidade a partir da melhoria gradativa das condi????es de entrega nos novos bairros atendidos pelo servi??o, al??m da satisfa????o e do reconhecimento da sociedade com a a????o de inclus??o social

Avalia????o das pr??ticas de gest??o do conhecimento na ag??ncia nacional de telecomunica????es

A Gest??o do Conhecimento ?? de suma import??ncia para as organiza????es em que o conhecimento desempenha papel essencial. Nesses casos, o conhecimento afeta o trabalho e determina mudan??as irrevers??veis, tanto na vida das organiza????es como das pessoas que l?? trabalham. Este estudo analisa o processo de planejamento, implementa????o e desenvolvimento de pr??ticas de gest??o do conhecimento na Anatel, Ag??ncia Nacional de Telecomunica????es. ?? orientado por uma abordagem te??rica que foca, particularmente, na sociedade em rede (Castells, 1999) e nas dimens??es da Gest??o do Conhecimento (Angeloni, 2008). Um grupo de servidores da Anatel foi entrevistado e responderam a um question??rio com o objetivo de se avaliar sua familiaridade com pr??ticas de Gest??o do Conhecimento. A inclus??o da Gest??o do Conhecimento como t??pico da nova vers??o do Regimento Interno da Ag??ncia foi examinada, para verificar se representa passo estrat??gico para sua ado????o pela Ag??ncia. O estudo avalia a motiva????o para a ado????o da Gest??o do Conhecimento, investiga a ocorr??ncia de pr??ticas de Gest??o do Conhecimento na Anatel, bem como o est??gio de sua implementa????o e o alcance de sua ado????o entre os usu??rios da Ag??ncia e pela sociedade em geral. Finalmente, o estudo analisa se as iniciativas j?? tomadas para implementar a Gest??o do Conhecimento s??o consistentes com as diretrizes estabelecidas no novo Regimento Interno e se tais a????es s??o coordenadas de forma a promover a efic??cia da Gest??o do Conhecimento na Anatel

An??lise da estrutura organizacional da fiscaliza????o do transporte rodovi??rio na ag??ncia nacional de transportes terrestres

Fiscalizar a presta????o dos servi??os de transporte interestadual e internacional de passageiros e de transporte rodovi??rio de cargas ?? atribui????o da Superintend??ncia de Fiscaliza????o da Ag??ncia Nacional de Transportes Terrestres ??? ANTT. Esta pesquisa visa analisar a efici??ncia e efic??cia desta estrutura organizacional