Intermediary Regions Research Articles

Improving sustainable performance of China's new energy industry through collaborative innovation network resilience

The sustainable development of the new energy industry is crucial and needs support from collaborative innovation networks (CINs). However, CINs may face hindrances or interruptions under multiple risk shocks, impeding their effectiveness in promoting sustainable performance (SP). Enhancing CIN resilience is essential for the normal operation of CINs and requires support from the innovation ecosystem. This study aims to improve CIN resilience by optimizing innovation ecological factors, thereby improving the SP of new energy industry. The study selects China's new energy industry as the empirical object. Firstly, the impacts of CIN resilience on SP are explored through regression analysis. Secondly, the impacts of nine driving factors proposed based on innovation ecosystem on CIN resilience were uncovered by the temporal exponential random graph model. Lastly, network simulation was utilized to study how to optimize CIN resilience through network edge addition strategies and identify key regional cooperations for enhancing CIN resilience more effectively. The results indicate that: (1) CIN resilience can improve SP, with adaptive capacity exerting the most promotional effect. (2) Innovation ecological factors dynamically and heterogeneously drive CIN resilience. Innovative market subjects and technical environments exhibit substantial positive impacts on CIN resilience. (3) Promoting innovation cooperations of intermediary bridge regions can optimize CIN resilience. This study offers practical strategies for Chinese local governments and other countries or regions to formulate effective industrial policies and provides valuable insights for new energy enterprises.

Overview of Brazilian Higher Education: The Perspective of the Civil Engineering Program

This scientific article proposes an enhanced analysis of Higher Education Institutions (HEIs) in Brazil, focusing on Public HEIs (Federal, State, and Municipal) and Private HEIs (Community-based, Confessional, Philanthropic, and for-profit). The adopted approach stems from a meticulous historical analysis of face-to-face Civil Engineering courses, considering the various intermediary regions in Brazil. The study is based on data from the National Higher Education Assessment System (SINAES), the Higher Education Census, as well as demographic and territorial data provided by IBGE, and information from CONFEA. The theoretical framework of this article is grounded in the essential concepts of Brazilian Higher Education, Higher Education Institutions, the National Higher Education Assessment System, Civil Engineering Courses, and the Civil Construction Industry. A relevant factor incorporated into this analysis is the impact of territory, encompassing not only physical and environmental characteristics but also cultural and infrastructural issues.

Diffusion tensor imaging of optic neuropathies: a narrative review.

Diffusion tensor imaging (DTI) has been implemented in a breadth of scientific investigations of optic neuropathies, though it has yet to be fully adopted for diagnosis or prognosis. This is potentially due to a lack of standardization and weak replication of results. The aim of this investigation was to review DTI results from studies specific to three distinct optic neuropathies in order to probe its current clinical utility. We reviewed the DTI literature specific to primary open-angle glaucoma (POAG), optic neuritis (ON), and traumatic optic neuropathy (TON) by systematically searching the PubMed database on March 1st, 2023. Four distinct DTI metrics are considered: fractional anisotropy (FA), along with mean diffusivity (MD, axial diffusivity (AD), and radial diffusivity (RD). Results from within-group, between-group, and correlational studies were thoroughly assessed. POAG studies most consistently report a decrease in FA, especially in the optic radiations, followed in prevalence by an increase in RD and then MD, whilst AD yields conflicting results between studies. It is notable that there is not an equal distribution of investigated DTI metrics, with FA utilized the most, followed by MD, RD, and AD. Studies of ON are similar in that the most consistent findings are specific to FA, RD, and MD. These results are specific to the optic nerve and radiation since only one study measured the intermediary regions. More studies are needed to assess the effect that ON has on the tracts of the visual system. Finally, only three studies assessing DTI of TON have been performed to date, displaying low to moderate replicability of results. To improve the level of agreement between studies assessing each optic neuropathy, an increased level of standardization is recommended. Both POAG and ON studies have yielded some prevalent DTI findings, both for contrast and correlation-based assessments. Although the clinical need is high for TON, considering the limitations of the current diagnostic tools, too few studies exist to make confident conclusions. Future use of standardized and longitudinal DTI, along with the foreseen methodological and technical improvements, is warranted to effectively study optic neuropathies.

Lateral Entorhinal Cortex Suppresses Drift in Cortical Memory Representations.

Memory retrieval is thought to depend on the reinstatement of cortical memory representations guided by pattern completion processes in the hippocampus. The lateral entorhinal cortex (LEC) is one of the intermediary regions supporting hippocampal-cortical interactions and houses neurons that prospectively signal past events in a familiar environment. To investigate the functional relevance of the activity of the LEC for cortical reinstatement, we pharmacologically inhibited the LEC and examined its impact on the stability of ensemble firing patterns in one of the efferent targets of the LEC, the medial prefrontal cortex (mPFC). When male rats underwent multiple epochs of identical stimulus sequences in the same environment, the mPFC maintained a stable ensemble firing pattern across repetitions, particularly when the sequence included pairings of neutral and aversive stimuli. With LEC inhibition, the mPFC still formed an ensemble pattern that accurately captured stimuli and their associations within each epoch. However, LEC inhibition markedly disrupted its consistency across the epochs by decreasing the proportion of mPFC neurons that stably maintained firing selectivity for stimulus associations. Thus, the LEC stabilizes cortical representations of learned stimulus associations, thereby facilitating the recovery of the original memory trace without generating a new, redundant trace for familiar experiences. Failure of this process might underlie retrieval deficits in conditions associated with degeneration of the LEC, such as normal aging and Alzheimer's disease.SIGNIFICANCE STATEMENT To recall past events, the brain needs to reactivate the activity patterns that occurred during those events. However, such reinstatement of memory traces is not trivial because it goes against the natural tendency of the brain to restructure the activity patterns continuously. We found that dysfunction of a brain region called the LEC worsened the drift of the brain activity when rats repeatedly underwent the same events in the same room and made them behave as if they had never experienced these events before. Thus, the LEC stabilizes the brain activity to facilitate the recovery of the original memory trace. Failure of this process might underlie memory problems in elderly and Alzheimer's disease patients with the degenerated LEC.

I-SATA: A MATLAB based toolbox to estimate current density generated by transcranial direct current stimulation in an individual brain

Objective. Transcranial Direct Current Stimulation (tDCS) is a technique where a weak current is passed through the electrodes placed on the scalp. The distribution of the electric current induced in the brain due to tDCS is provided by simulation toolbox like Realistic volumetric Approach based Simulator for Transcranial electric stimulation (ROAST). However, the procedure to estimate the total current density induced at the target and the intermediary region of the cortex is complex. The Systematic-Approach-for-tDCS-Analysis (SATA) was developed to overcome this problem. However, SATA is limited to standardized (MNI152) headspace only. Here we develop individual-SATA (i-SATA) to extend it to individual head. Approach. T1-weighted images of 15 subjects were taken from two Magnetic Resonance Imaging scanners of different strengths. Across the subjects, the montages were simulated in ROAST. i-SATA converts the ROAST output to Talairach space. The x, y and z coordinates of the anterior commissure (AC), posterior commissure (PC), and Mid-Sagittal (MS) points are necessary for the conversion. AC and PC are detected using the acpcdetect toolbox. We developed a method to determine the MS in the image and cross-verified its location manually using BrainSight®. Main results. Determination of points with i-SATA is fast and accurate. The i-SATA provided estimates of the current-density induced across an individual’s cortical lobes and gyri as tested on images from two different scanners. Significance. Researchers can use i-SATA for customizing tDCS-montages. With i-SATA it is also easier to compute the inter-individual variation in current-density across the target and intermediary regions of the brain. The software is publicly available.

Prefrontal–hippocampal interactions in episodic memory

The roles of the hippocampus and prefrontal cortex (PFC) in memory processing - individually or in concert - are a major topic of interest in memory research. These brain areas have distinct and complementary roles in episodic memory, and their interactions are crucial for learning and remembering events. Considerable evidence indicates that the PFC and hippocampus become coupled via oscillatory synchrony that reflects bidirectional flow of information. Furthermore, newer studies have revealed specific mechanisms whereby neural representations in the PFC and hippocampus are mediated through direct connections or through intermediary regions. These findings suggest a model of how the hippocampus and PFC, along with their intermediaries, operate as a system that uses the current context of experience to retrieve relevant memories.

Histopathological effects of the herbicide atrazine on gills of the Brazilian endemic bivalve Diplodon expansus

ABSTRACTDue to their benthic filter-feeding habits and high bioaccumulation potential of metals and organic compounds, bivalve molluscs have been widely used in studies in the field and laboratory to assess the toxic effects of several compounds discharged in rivers, oceans and estuaries. However, most ecotoxicological studies use invasive exotic species, while the response of native species is poorly known. The Brazilian endemic species Diplodon expansus occurs in rivers near areas of intense agricultural activity, and atrazine is currently one of the main residues of pesticides found in water bodies of the Brazilian territory. This study was aimed at examining the toxicity of different atrazine concentrations to a Brazilian native mollusc by analysing the histology, histochemistry and ultrastructure of its gill filaments. The cells that comprise the frontal and intermediary regions of gill filaments were the most affected by the herbicide and responses associated with damage and protection were observed. The response of tissues and cells were dose-dependent. Higher concentrations of herbicide caused more severe alterations in large areas of the gills. The persistence of the alterations observed might result in severe functional problems in the gills of these animals, negatively affecting their performance and health.

Hepatocyte nuclear factor 4α (HNF4α) in coordination with retinoic acid receptors increases all-trans-retinoic acid-dependent CYP26A1 gene expression in HepG2 human hepatocytes.

CYP26A1 expression is very highly induced by retinoic acid (RA) in the liver, compared to most other tissues, suggesting that a liver-enriched factor may be required for its physiological transcriptional response. HNF4α is a highly conserved liver-specific/enriched member of nuclear receptor superfamily. In this study, we hypothesized that HNF4α and RARs may cooperate in an RA-dependent manner to induce a high level of CYP26A1 expression in liver cells. Partial inhibition of endogenous HNF4α by siRNA reduced the level of RA-induced CYP26A1 mRNA in HepG2 cells. Cotransfection of HNF4α, with or without RARs, demonstrated RA-dependent activation of a human CYP26A1 promoter-luciferase construct. Analysis of a 2.5-kbp putative CYP26A1 promoter sequence identified five potential HNF4α DNA response elements: H1 located in a proximal region overlapping with an RAR element-1 (RARE1 or R1); H2 and H3 in the distal region, close to RARE2 (R2) and RARE3 (R3); and H4 and H5 in intermediary regions. In EMSA and ChIP analyses HNF4α and RARs binding in the proximal and distal CYP26A1 promoter regions was significantly higher in RA-treated cells. Mutational analysis of the individual HNF4α DNA-response elements identified H1 as the major site for HNF4α binding because mutation of H1 inhibited the promoter activity by ~90%, followed by H2 mutation with less than 40% inhibition. Our results indicate that HNF4α coordinates with RARs in an RA-dependent manner to strongly induce CYP26A1 gene expression in the liver, which may explain the high level of response to RA observed in vivo.

Hungary and the Balkans

As regards the Balkans, Hungary is one of the intermediary regions in Europe. At the same time, the Balkans is the tie-up territory between Turkey, one of the emerging regions today, and Hungary, which aims to cooperate with it. Being a NATO and EU member state it takes part in the geopolitical games that are played between the EU, Russia, the USA and some of the countries of the Islamic world. These dealings fundamentally determine tasks in Hungarian foreign policy, cultural policy, economic policy, security- and defence policy for the forthcoming decades. Hungary acts as a gate between Western Europe and the Balkans. This role used to be more dominant in previous centuries of Hungarian history than it is today, not least because the country's size and strength significantly decreased after the Trianon Treaty. Many of the historical, imperial reflexes have remained, but without any imperial gravity. Today we are just one of the intermediary regions that have relations with the Balkans and form a bridge to Europe. The accelerated alteration in the world order, the BRICS countries and the emergence of some important middle-sized states, such as Turkey, make adaptation inevitable for our country. This is what the policy of 'Eastern opening' is about.

Hepatocyte nuclear factor 4α (HNF4α) in coordination with retinoic acid receptors (RARs) increases all‐trans‐retinoic acid (RA)‐dependent CYP26A1 gene expression in hepatocytes

CYP26A1, a cytochrome P450, catalyzes exclusively the oxidative inactivation of all‐trans‐RA, the major hormonal metabolite of vitamin A. RA is a pan‐agonist of RARs, promoting RAR binding to DNA response elements of numerous genes. CYP26A1 is very highly induced by RA in the liver, generally to a greater extent than in other tissues, suggesting that a liver‐specific factor may be required for its physiological transcriptional response. In this study, we cotransfected HNF4α, with or without RARs, and demonstrated RA‐dependent activation of a human CYP26A1 promoter‐luciferase construct in HepG2 cells. Analysis of a 2.5‐kbp putative CYP26A1 promoter sequence identified 5 putative HNF4α DNA response elements: H1 located in a proximal region overlapping with an RAR element‐1 (RARE1); H2 and H3 in the distal region, close to RARE2 and RARE3; and H4 and H5 in intermediary regions. Chromatin immunoprecipitation analysis showed significantly increased binding of HNF4α and RARs in the proximal and distal CYP26A1 promoter regions in RA‐treated cells, as compared to the control. Mutational analysis of the individual HNF4α DNA‐response elements identified H1 as the major site for HNF4α binding because H1 mutation inhibited the promoter activity by ~90%, followed by H2 and H3 mutation each with ~50% inhibition. Therefore, our results indicate that HNF4α, as a liver‐enriched nuclear transcription factor, may coordinate with RARs to strongly induce CYP26A1 gene by RA, which may explain the high level of response to RA observed in the liver. (NIH CA‐90214)

Liver and gallbladder cancer in immigrants to Sweden

Background The changes of cancer incidence upon immigration can be used as an estimator of environmental influence on cancer risk. We studied site-specific liver and biliary cancers in first-generation immigrants to Sweden with an aim to search for aetiological clues and to find evidence for indigenous incidence rates. Material and methods We used the nation-wide Swedish Family-Cancer Database to calculate standardised incidence ratios (SIRs) in immigrants compared to native Swedes. Results A total of 1428 cancers were identified in immigrants whose median ages (years) at immigration were 27 for men and 26 for women and whose median diagnostic ages were 64 and 66, respectively. The highest SIRs of 6.7 for primary liver cancer were observed for men from East Asia and sub-Saharan Africa. Increased SIRs were recorded for male immigrants from previous Yugoslavia (1.78), Southern Europe (2.91), Turkey (2.15) and Asian Arab countries (2.89). For gallbladder cancer, only women from the Indian subcontinent (3.84) and Chile (2.34) had increased risk while some Northern European immigrants showed decreased risks. Conclusions Primary liver cancer was increased in immigrants from endemic regions of hepatitis B virus infection but also from large regions lacking cancer incidence data, North Africa, Asian Arab countries, Turkey and previous Yugoslavia; these are probably intermediary risk regions for this infection. The consideration of these regions as risk areas would justify active diagnostic and vaccination programs. The increase in gallbladder cancer in Chileans and Indians suggests that some persistent damage was inflicted before emigration, characterisation of which will be a challenge for aetiological studies.

Structure and dynamics of the periphytic algae community of Iraí reservoir, Paraná State, Brazil

In order to analyze the structure and dynamics of the periphytic community in Iraí reservoir, which is considered a eutrophic environment, samples were taken in two seasons: summer (April) and winter (September) of 2002, in littoral areas from three regions of the reservoir (upper, intermediary and lower). Aquatic macrophytes were used as sampling substrates, because they were found in all sampling sites. A total of 297 species was recorded (225 in April, 73 exclusive to this season; and 224 in September, with 72 exclusive taxa). Bacillariophyceae predominated in all regions in both seasons, in number of species as well as in density. There were differences in richness among zones; intermediary and lower regions were more similar, mainly in September. The periphytic algae density differed significantly between seasons (F = 16,48; p = 0,002), with lower values in the summer. No significant difference in density was recorded among zones.

Cosmarium (Desmidiaceae, Zygnemaphyceae) da ficoflórula perifítica do reservatório de Rosana, bacia do rio Paranapanema, Paraná/São Paulo, Brasil

Com este trabalho, objetivou-se divulgar espécies pertencentes ao gênero Cosmarium Corda, da comunidade perifítica de três regiões do reservatório de Rosana, Sul do Brasil. As amostras foram coletadas durante o período de verão e inverno em distintas regiões ao longo do eixo rio-barragem do reservatório. Os substratos coletados, sempre na região litorânea e em todos os pontos de coleta, foram pecíolos de Eichhornia azurea Kunth. Foram identificados 48 táxons, distribuídos nas regiões fluvial, intermediária e lacustre. Dentre estes táxons, 45 foram registrados para o período do verão e 31 para o inverno. Maior riqueza de espécies ocorreu na região lacustre para ambos os períodos de coleta. Cosmarium abbreviatum Raciborski var. minus (West & West) Krieger & Gerloff, C. granatum Brébisson ex Ralfs, C. pseudoconnatum Nordstedt, C. punctulatum Brébisson e C. quadrum Lundell var. minus Nordstedt ocorreram em todas as regiões amostradas e em ambos os períodos.

Alterações do epitélio branquial e das lamelas de tilápias (Oreochromis niloticus) causadas por mudanças do ambiente aquático em tanques de cultivo intensivo

Objetivou-se analisar o comportamento do epitélio branquial de tilápias, cultivadas em tanques posicionados em diferentes altitudes e interconectados por tubos de PVC. Filamentos branquiais de quatro espécimes de quatro tanques (T1, T2, T3 e T4) interconectados seqüencialmente foram submetidos à rotina histológica, para obtenção de cortes de 5µm de espessura, os quais foram corados com Hematoxilina-Eosina, ou submetidos à técnica histoquímica para glicoconjugados: PAS + solução de diástase ou Alcian Blue pH 2,5 ou Alcian Blue pH 1,0. Considerando as regiões basal, intermediária e apical dos filamentos, mensurou-se a área lamelar e contou-se o número de células mucosas em cada uma dessas regiões, o que correspondia a 0,56 mm². Verificou-se que a concentração de oxigênio, pH e a temperatura se reduziam progressivamente com a passagem da água de um tanque para outro. Em função disso, constatou-se um aumento abrupto do número de células mucosas e da área lamelar no T2, e uma redução progressiva destas medidas nos tanques que recebiam água do T2. Além disso, observou-se nos animais do T2, T3 e T4, descolamento do epitélio branquial, hiperplasia celular no espaço interlamelar e telangectasias. Conclui-se que o ambiente aquático de tanques interconectados seqüencialmente por tubos de PVC se altera ao passar de um tanque para o outro, e que estas flutuações físico-químicas se refletem no comportamento do epitélio branquial através de variações da área lamelar e do número de células mucosas.

VHF/UHF radar observations of tropical mesoscale convective systems over southern India

Abstract. Several campaigns have been carried out to study the convective systems over Gadanki (13.5° N, 79.2° E), a tropical station in India, using VHF and UHF radars. The height-time sections of several convective systems are investigated in detail to study reflectivity, turbulence and vertical velocity structure. Structure and dynamics of the convective systems are the main objectives of these campaigns. The observed systems are classified into single- and multi-cell systems. It has been observed that most of the convective systems at this latitude are multi-cellular in nature. Simultaneous VHF and UHF radar observations are used to classify the observed precipitating systems as convective, intermediary and stratiform regions. Composite height profiles of vertical velocities in these regions were obtained and the same were compared with the profiles obtained at other geographical locations. These composite profiles of vertical velocity in the convective regions have shown their peaks in the mid troposphere, indicating that the maximum latent heat is being released at those heights. These profiles are very important for numerical simulations of the convective systems, which vary significantly from one geographical location to the other. Keywords. Meteorology and atmospheric dynamics (Mesoscale meteorology; Convective processes) – Radio science (Remote sensing)

Aspectos anatômicos e fisiológicos de plantas de guaco submetidas a diferentes fotoperíodos

O guaco (Mikania glomerata Sprengel) é espécie de uso medicinal conhecida pela atividade broncodilatadora. Muitos estudos têm evidenciado mudanças nas características anatômicas e fisiológicas de plantas medicinais sob influência de condições de radiação. Neste trabalho analisou-se a influência de fotoperíodos (8; 12; 16 e 20 h) na anatomia foliar, nos teores de clorofila e condutância estomática em três regiões da planta. Após 90 dias de tratamento, plantas adultas e com diferentes tamanhos influenciados pelos fotoperíodos foram submetidas às avaliações anatômicas e fisiológicas. Os teores de clorofila foram maiores nos fotoperíodos de 8 e 12 h nas regiões superior e mediana da planta e menores no fotoperíodo de 8 h na região basal. A condutância e densidade estomática apresentaram relação inversa ao aumento do fotoperíodo, sendo significativamente decrescente do ápice para a base da planta. Houve aumento da espessura da epiderme adaxial nas regiões mediana e basal da planta até o fotoperíodo de 16 h. Nestas regiões houve aumento progressivo do parênquima esponjoso até o fotoperíodo de 20 h. Verificou-se modificações no tamanho e organização dos feixes vasculares influenciadas pelos fotoperíodos.

The interposito-rubrospinal system. Anatomical tracing of a motor control pathway in the rat

The cerebello-rubromotor pathway, impinging on both spinal and facial motor nuclei, has been traced in the rat, using the bidirectional transport of horseradish peroxidase-wheat germ agglutinin conjugate. After injection of the tracer in the red nucleus (NR), retrograde labelling shows a topical arrangement of the cerebellorubral connection. The nucleus lateralis projects to the parvocellular NR (NRp) and the nucleus interpositus to the magnocellular NR (NRm). The nucleus interpositus anterior (NIA) reaches the entire NRm and this projection is topographically arranged: the medial NIA sends fibres ventrally, the lateral NIA dorsally. The medial two-thirds of the nucleus interpositus posterior (NIP) project only to the medial aspect of the NRm, with no apparent organization. No connection has been found between the lateral third of NIP and the NRm. After injection of the tracer in the spinal cord or the nucleus of the facial nerve, retrograde labelling is observed almost throughout the entire caudorostral extent of the NR, although labelling is more scant in NRp than in NRm. Rubrospinal and rubrofacial projections are somatotopically arranged in the dorsoventral direction: ventrolateral regions of NR reach the lumbar cord, medioventral regions the lower cervical levels, intermediary regions the upper cervical levels and finally the dorsalmost part of the NR projects to the nucleus of the facial nerve. After injection of the tracer in the cerebellar nuclei, anterograde labelling in the NR shows that interpositorubral connections determine two subregions in the NR: a lateral one under the exclusive control of the NIA, and a medial one under the control of both NIA-NIP afferents. It confirms in addition the topography of the NIA-NRm projection and shows the preponderant participation of the NIA afferents to the interpositorubral connection. Thus, it appears from our results that the cerebellorubral arrangement matches, to a great extent, the “rubromotor” efferent organization.

Regulation of Ketogenesis

The analysis of the initial-rate kinetics of the liver mitochondrial acetyl-CoA acetyltransferase (acetoacetyl-CoA thiolase) in the direction of acetoacetyl-CoA synthesis under product inhibition was performed. 1. Acetyl-CoA acetyltransferase shows a hyperbolic response of reaction velocity to changes in acetyl-CoA concentrations with an apparent Km of 0.237 +/- 0.001 mM. 2. CoASH is a (non-competitive) product inhibitor with a Kis of 22.6 microM and shifts the apparent Km for acetyl-CoA to the physiological concentration of this substrate in mitochondria (S0.5 = 1.12 mM in the presence of 121 microM CoASH). 3. CoASH causes a transformation of the Michaelis-Menten kinetics into initial-rate kinetics with four intermediary plateau regions. 4. The product analogue desulpho-CoA triggers a negative cooperativity as to the dependence of the reaction velocity on the acetyl-CoA concentration. These product effects drastically desensitize the acetyl-CoA acetyltransferase in its reaction velocity response to the acetyl-CoA concentrations and simultaneously extend the substrate dependence range. Thus a control of acetoacetyl-CoA synthesis by the substrate is established over the physiological acetyl-CoA concentration range. We suggest that this control mechanism is the key in establishing the rates of ketogenesis.

A critical analysis of kinetic data of 3‐hexulosephosphate synthases MICHAELIS‐MENTEN or complex characteristics

AbstractInvestigations of the 3‐hexulosephosphate synthase (HPS) from different methylotrophic bacteria have revealed apparent discrepancies in kinetic behaviour. In all methanol‐utilizing species investigated by us the kinetic characteristics showed intermediary plateau regions. Therefore, this behaviour is assumed to be a general feature of the HPS from all non‐methane‐utilizing methylotrophic bacteria. However, this assumption is in contrast to the results of other authors. Both for Methylomonas M15 (SAHM et al. 1976) and Methylomonas aminofaciens 77 a (KATO et al. 1977, 1978) MICHAELIS‐MENTEN kinetics of the HPS were stated.To check the validity of our assumption we have analyzed the kinetic data given by others. Indications of the existence of intermediary plateau regions could be found with the enzyme from Arthrobacter globiformis (BYKOVSKAYA and VORONKOV 1977) and Methylomonas aminofaciens 77 a (KATO et al. 1978). Furthermore, biphasic ARRHENIUS plots indicate a multiple character of the HPS from these species as could already be demonstrated with the enzyme from Bacterium MB 58 and Pseudomonas oleovorans. In addition, causes which may obscure the detection of intermediary plateau regions are demonstrated.

A critical analysis of kinetic data of 3-hexulosephosphate synthases. Michaelis-Menten or complex characteristics.

Investigations of the 3-hexulosephosphate synthase (HPS) from different methylotrophic bacteria have revealed apparent discrepancies in kinetic behaviour. In all methanol-utilizing species investigated by us the kinetic characteristics showed intermediary plateau regions. Therefore, this behaviour is assumed to be a general feature of the HPS from all non-methane-utilizing methylotrophic bacteria. However, this assumption is in contrast to the results of other authors. Both for Methylomonas M15 (SAHM et al. 1976) and Methylomonas aminofaciens 77a (KATO et al. 1977, 1978) MICHAELIS-MENTEN kinetics of the HPS were stated. To check the validity of our assumption we have analyzed the kinetic data given by others. Indications of the existence of intermediary plateau regions could be found with the enzyme from Arthrobacter globiformis (BYKOVSKAYA and VORONKOV 1977) and Methylomonas aminofaciens 77a (KATO et al. 1978). Furthermore, biphasic ARRHENIUS plots indicate a multiple character of the HPS from these species as could already be demonstrated with the enzyme from Bacterium MB 58 and Pseudomonas oleovorans. In addition, causes which may obscure the detection of intermediary plateau regions are demonstrated.