bluuebunny/crossref_metadata_2025 huggingface dataset:
Cultured rat cortical astrocytes synthesize melatonin: absence of a diurnal rhythm
Authors: Liu Ya‐Jing , Zhuang Jun , Zhu Hong‐Yan , Shen Yu‐Xian , Tan Zhong‐Lin , Zhou Jiang‐Ning
Published: June 2007

Abstract:  Melatonin not only plays a major role in the regulation of circadian rhythms, but is also involved in antioxidative defense and immunomodulation. Circulating melatonin levels are derived primarily from the pineal gland while other sources of melatonin have also been reported. Here, we show for the first time that astrocytes from the rat cortex and glioma C6 cell line synthesize melatonin in vitro. In addition, we show the presence of serotonin, the precursor of melatonin and the two key enzymes in the pathway of melatonin synthesis, i.e. N‐acetyltransferase and hydroxyndole‐O‐methyltransferase in the cultured rat cortical astrocytes. Release of melatonin into the culture medium showed no diurnal changes. These point to astrocytes as a local source of melatonin in the rat brain. Its exact physiological function remains a topic for future studies.
Bisquaternary Oximes as Reactivators of Tabun‐Inhibited Human Brain Cholinesterases: An in vitro Study
Authors: Kuca Kamil , Jun Daniel , Cabal Jiri , Musilova Lucie
Published: June 2007

Abstract:   Intoxications caused by tabun nerve agent are generally very hard to treat by convential acetylcholinesterase (AChE) reactivators. Due to this, new AChE reactivators are still developed. In this study, we have tested three new promising bisquaternary AChE reactivators: K027, K033 and K048. These reactivators were previously tested on rat brain homogenate. To mimic reality, we studied the potency of these new oximes to reactivate tabun‐inhibited human brain cholinesterases. As is evident from the results, reactivator K048 (reactivation 40%) surpassed all reactivators tested in this study [including the most promising ones, namely trimedoxime (37%) and obidoxime (33%)]. Moreover, if compared to our previous results from rat brain studies, species differences were demonstrated.
Comparison of methods for determining platelet numbers and volume in cavalier King Charles spaniels
Authors: Bertazzolo W. , Comazzi S. , Sesso L. , Scarpa P. , Ru G. , Paltrinieri S.
Published: June 2007

Objective:The purpose of this study was to compare platelet concentration in cavalier King Charles spaniels (CKCS) measured by different methods commonly used in veterinary hospitals and commercial laboratories.

Methods:Blood samples obtained from 41 (CKCS) were analysed by impedance cell counter, laser cell counter and microscopic estimation. Quantitative buffy coat analysis was performed only on 17 samples, selected from (CKCS) that had low platelet counts detected by cell counters. Platelet counts, platelet estimations and platelet parameters using these different methods were compared.

Results:The median platelet number was lower when estimated using impedance cell counter (1363×109/l) with respect to laser cell counter (1723×109/l), microscopic estimation (2383×109/l) or quantitative buffy coat analyser (2923×109/l) (P<0·01). Although impedance cell counter, laser cell counter and microscopic estimation were positively correlated, there was no acceptable agreement among methods. (CKCS) with macrothrombocytes in blood smears had significantly lower counts on impedance cell counter, laser cell counter and microscopic estimation. The percentages of (CKCS) with platelet count < 1003×109/l were 34·1 per cent (impedance cell counter), 26·8 per cent (laser cell counter), 22·0 per cent (microscopic estimation) (not statistically different) and 5·8 per cent (quantitative buffy coat analyser) (P<0·05).

ClinicalSignificance:(CKCS) with macrothrombocytosis have low platelet counts on impedance cell counters, laser cell counters and microscopic estimation. (CKCS) with low platelet counts may have a normal platelet crit detected by a quantitative buffy coat analyser and thus a normal circulating platelet mass.
Recurrent supraventricular arrhythmias in a dog with atrial myocarditis and gastritis
Authors: Tyszko C. , Bright J. M. , Swist S. L.
Published: June 2007

This report describes a dog with recurrent atrial fibrillation and atrial flutter associated with chronic gastritis. Although no underlying structural heart disease was apparent antemortem or on gross post‐mortem examination, chronic atrial myocarditis was seen on histopathological examination. Atrial myocarditis is a recognised cause of atrial fibrillation in human beings with presumed lone fibrillation, and an association between supraventricular tachyarrhythmias and infectious agents has been made.
Set up of trials, reporting and publishing
Authors: Mayr W. R.
Published: June 2007

General guidelines to set up trials or experiments are presented, as well as guidelines to report and publish the results that have been obtained.
Getting the best out of human leucocyte antigen typing
Authors: Faner R. , Palou E. , Juan M. , Pujol Borrell R.
Published: June 2007

Getting value out of human leucocyte antigen (HLA) laboratories requires not only good technology and software but also an understanding of the role of HLA in the immune response and in immunopathology. In this paper, we give some historical background that explains why HLA remains a difficult subject for most laboratory and clinical scientists and we comment on what is known of their function as antigen‐presenting molecules. We review then the state of knowledge on the genetics of HLA, which still contains many unresolved questions, not all that surprising since, despite the myriad of association studies, only three extended haplotypes have been fully sequenced to date. The HUGO and HapMap projects have revealed the daunting complexity of this genomic region that not only contains a extremely high density of genes, but it is also the most actively transcribed region of the human genome, probably because it contains many histone‐ and tRNA‐coding genes. Finally, the main typing techniques and what the future may bring are briefly discussed.
Cord blood banking: ethical and cost–benefit aspects
Authors: Querol S.
Published: June 2007

Cord blood represents a new source of stem cells on the edge of fetal and postnatal life. Increasing interest in stem cell therapy has moulded cord blood banking scope, evolving to a multidisciplinary platform exceeding the classic field of haemotherapy. This review intends to re‐analyse this and presents the new aspects of cord blood banking that direct it to a model of cell pharmacy in a globalized world.
Screening of anti‐HPA‐1a antibodies in HPA‐1a‐negative mothers
Authors: Husebekk A. , Kjær Killie M. , Kjeldsen‐Kragh J. , Skogen B.
Published: June 2007

Results from a study of more than 100 000 pregnant women show that the pathophysiology of neonatal alloimmune thrombocytopenia (NAIT) and haemolytic disease of the newborn (HDN) has many equalities [1]. It has been reported that NAIT is more than three times more frequent compared with HDN. This makes it tempting to consider a design for screening for HPA 1a negativity and follow up in/after the pregnancy based on the same principles as for RhD‐negative pregnant women. Even without available vaccination, it is strongly indicated that screening and Caesarean section 2–4 weeks prior to term in mothers with the HPA‐1a‐negative platelet type, reduce neonatal morbidity and mortality due to NAIT.
Blood transfusion services in the countries that joined EU in the last years: Poland
Authors: Łętowska M. , Antoniewicz‐Papis J.
Published: June 2007

The activity of Polish Blood Transfusion Service (BTS) is based on the Public Blood Transfusion Service Act voted by the Polish Parliament. There are 21 regional blood transfusion centers, one military blood transfusion center and one blood transfusion center (BTC) of the Ministry of Internal Affairs. The Institute of Haematology and Transfusion Medicine (IHTM) is responsible for issuing guidelines for blood transfusion medicine. All BTCs must have an accreditation from the Ministry of Health. In Poland, there is a national system of haemovigilance. Hospitals are obliged to immediately report all post‐transfusion complications and ‘near‐miss’ events. Immunological, viral, bacterial as well as transfusion‐related acute lung injury reactions are supervised by IHTM. Qualification improvement and training of personnel is one of the priorities of Polish BTS.
Data interchange and related technologies in transfusion medicine
Authors: Bruce P.
Published: June 2007

The transfusion medicine data interchange needs involve varying types of equipment and systems including blood collection and processing systems, component separation automation, laboratory instruments and automation systems (e.g. the ones used for screening of infectious markers), and various information management systems (e.g. laboratory information management systems donation/production management, and invoicing systems). Interfacing challenges and extra costs arise due to a lack of a common and open definition for the instrument interface, and a lack of a common conceptual framework for data interchange between systems and instruments. Standardization of data interchange is a need recognized by the end users and vendors. This is why the ISBT has launched a new Automated System Interface Task Force in September 2006 to establish a standard specification for transferring information between equipment and information management systems.
Blood transfusion services in countries that joined the EU in the last years: Czech Republic
Authors: Turek P. , Zimová R.
Published: June 2007

The Czech Republic is a country in the middle of Europe with 10·3 million inhabitants and 80 000 km2. It became a European Union (EU) member in 2004. Blood transfusion service is disperse, hospital based. Blood is collected mostly from voluntary non‐remunerated blood donors and the country is self‐sufficient in blood components and plasma for fractionation. Predeposit autologeous programme is popular and covers around 4·5% of red cells needs. Donor population is stable and relatively safe. Total of 21 HIV positive donors have been detected during last 20 years, the incidence of hepatitis in blood donors is decreasing being below 0·10 pro mille for hepatitis B virus and below 0·20 pro mille for hepatitis C virus in 2005. European standards have been accepted and implemented during last 15 years; safety (quality) and general availability being the priorities. Donor selection, blood collection, processing and testing comply with EU directives. Producers of blood components (blood establishments) are under control of the state authority (State Institute for Drug Control). Recommendations based on expert opinion are available for clinical use of blood. Adverse effects of treatment are followed and investigated. Costs of blood components and plasma products are covered by general health insurance.
Errare humanum est ... but it is also human to prevent errors
Authors: Cummins D.
Published: June 2007

Identification errors remain the most serious and the most common type of error in blood transfusion practice. Adverse events may occur when a patient has similar or identical identifiers to another patient (a ‘doppelgänger’), is doubly registered (a ‘duplicate registration’), or when registration details are derived from two or more separate sources (a ‘hybrid registration’). Such categorization provides a valuable conceptual framework for the development of appropriate risk management strategies.

 Distinguishing doppelgängers from duplicate registrations is not always easy. A search of the Harefield Hospital Patient Administration System (PAS) database revealed 39 registrations that shared a forename, surname and date of birth with at least one other registration. Thirty‐seven of these cases involved a duplicate registration, one involved a hybrid registration, and one involved a doppelgänger. A national strategic tracing service is available in the UK to help resolve difficult cases.

 Little attention has been directed at the extent to which risk reduction strategies in this area are in conflict with political and regulatory agendas. Most notable are initiatives that aim to preserve patient confidentiality. The less that is known about an individual, the greater is the risk he will be mistaken for someone who possesses similar identifiers to himself.

 An important, but largely unexplored, contributor to patient identification errors is innate cognitive bias. The fundamental concept underlying all blood transfusion – unique patient identity – is inherently ambiguous and vulnerable to a range of misperceptions, particularly with regard to the twin themes of coincidence and uniqueness. A major challenge will be to develop approaches in practice and education that are suitably informed by insights gleaned from cognitive and evolutionary psychology.
Process controls to avert mistransfusion
Authors: AuBuchon J. P.
Published: June 2007

The key to error reduction in medicine is to focus on the process being applied and not just those performing the process. As human error is inevitable, it is necessary to evaluate and re‐design processes so that errors cannot happen or are reliably detected and interdicted before patient harm is the outcome. One tool that is useful to ensure that a process has been completed correctly is a ‘process control’, a step in a process the successful completion of which ensures that all preceding critical steps have been accomplished successfully. (An example from immunohematology is the use of ‘check cells’.) To reduce the risk of mistransfusion, for example, process controls can be applied by using bedside systems that apply to the patient's bar‐coded identification to the label of a pretransfusion testing sample or by using a mechanical barrier system to ensure that the person who gave that sample is the one receiving the transfusion. Other approaches include the use of remote‐release refrigeration systems or the use of only Group O red cells for transfusion until the patient's ABO group has been confirmed on a second sample. Applying techniques like this would significantly reduce the ongoing – but avoidable – catastrophes of acute hemolytic transfusion reactions.
Potential applications of dendritic cells
Authors: De Vries I. Jolanda M. , Punt C. J. A. , Adema G. J. , Figdor C. G.
Published: June 2007

Dendritic cells (DCs) are the professional antigen‐presenting cells of the immune system. Following infection or inflammation they undergo a complex process of maturation, and migrate to lymph nodes where they present antigens to T cells. Their decisive role in inducing immunity formed the rationale for DC immunotherapy: DCs loaded with tumor antigens are injected into cancer patients to stimulate T cells to eradicate tumors. Effective immune responses and favourable clinical outcomes have indeed been observed, but only in a minority of patients.

For effective immunotherapy DCs need to traffic throughout the vascular and lymphatic system to reach the T‐cells located within lymph nodes. Though most immunotherapeutic agents are administered intravenously, DCs are predominantly administered intradermally. We observed that < 5% of intradermally administered mature DCs reach the draining lymph nodes amounting to inefficient homing. Despite this low number we could measure effective immune responses in some patients, but generally this may be too low.

We demonstrated that DC maturation is a prerequisite to exert their immunostimulatory capacity in vivo. Immuno‐monitoring revealed a remarkable difference in immune responses. In patients vaccinated with immature DC the KLH responses as well as DTH reactivity against KLH and tumor‐peptides were weak and absent, respectively. In contrast, in patients vaccinated with mature DC a pronounced T cell as well a B cell response (IgG) against KLH were observed. Analysis of the response against the tumor peptides demonstrated little or no reactivity in blood. However, following intradermal administration of a delayed type hypersensitivity (DTH) challenge with gp100‐ and tyrosinase‐peptide loaded DC essentially all patients vaccinated with mature DC showed a positive induration. Moreover, we showed the predictive value of the presence or absence of antigen‐specific T cells in biopsies from DTH sites. In clinically responding patients, T cells specific for the antigen preferentially accumulated in the DTH site in accordance with the applied antigen in the DTH challenge.
Government, media and decision making in blood transfusion
Authors: AuBuchon J. P.
Published: June 2007

Ensuring continued financial and moral support of a transfusion system's operation is essential. Although the public remains concerned about problems that have been greatly reduced in magnitude, such as HIV and HCV, we will need to engage them in the problems we now wish to address that are less well‐known to them. To do this, we will need to present the information in formats that they understand, framed in ways that are most likely to result in public support. While acknowledging the psychological factors that provoke dread and outrage in the media, presenting all that we know in an open manner and engaging the public through transparent decision making should provide us their support to tackle the problems that pose the greatest risk to their safety when transfused.
Effect of recipient immune status on the persistence and clinical consequences of transfused leucocytes
Authors: Reed William , Utter Garth H. , Lee Tzong‐Hae , Busch Michael P.
Published: June 2007

The presence of a population of allogeneic cells underlies and partially defines both microchimerism (MC) and graft‐versus‐host disease (GVHD). Although the relationship between these two apparently distinct clinical entities is not well understood, it is plausible that progenitor cell dose, histocompatibility, recipient immune status and genetic profile all help determine whether allogeneic cells die, persist as a minor population or proliferate in a GVHD response. Although MC has been described, at low levels, in association with pregnancy and autoimmune disease, much higher levels of MC have recently been found in association with blood transfusion. This transfusion‐associated microchimerism (TA‐MC) has thus far been identified only in patients multiply transfused for severe traumatic injury, which is well documented to induce broad short‐term suppression of both the innate and adaptive arms of the host immune system. In this review, we will summarize the limited available data concerning the clinical, immunologic and genetic settings in which TA‐MC and GVHD develop and examine the factors that may influence their development. We will not address humoral alloimmunization as a result of transfusion here because its relationship to donor leucocyte persistence is unknown.
Controversy concerning platelet dose
Authors: Heddle N. M.
Published: June 2007

The highest level of support for evidence based decisions is the randomized controlled trial (RCT); however, RCT results are only useful if the study has strong internal and external validity. There have been a number of clinical trials that have addressed the issue of the optimal platelet dose; however, none of these studies have provided definitive data on the optimal platelet dose due to a variety of methodological issues associated with the study designs. Currently two randomized controlled trials have been implemented to address the issue of optimal platelet dose. The results of these trials will not be available until 2007–2008. The BEST (Biomedical Excellence for Safer Transfusion) Collaborative has initiated a platelet dose study comparing the frequency of WHO bleeding Grade 2 with low and standard dose platelets. The Transfusion Medicine/ Haemostasis Clinical Trials Network (CTN) is also performing a platelet dose study comparing three treatment strategies (high, standard and low dose platelets). There were numerous methodological issues that had to be considered when designing these two studies. More recently some European investigators have questioned the need for prophylactic platelet transfusions and several studies are currently underway to investigate the efficacy of changing this practice.
European best practice in blood transfusion: improvement of quality‐related processes in blood establishments
Authors: Seidl Christian , O’Connell Marie , Delayney Frances , Douglas Angus McMillan , Gorham Martin , Van Krimpen Petra , Letowska Magdalena , Sobaga Leslie , De Wit Jeroen , Seifried Erhard ,   on behalf of the Project's participants
Published: June 2007

Transfusion medicine is an expanding field comprising the interaction between several medical disciplines. Looking at the ‘vein to vein process’ covering the donation of blood by the voluntary donor up to the application of blood components to patients, modern blood transfusion services comprise a large variety of sociomedical functions. The production of standard cellular blood components, such as erythrocyte and thrombocyte concentrates, plasmatic blood components as well as special cellular components such as blood stem cells, mesenchymal cells or granulocytes will require an extensive laboratory testing repertoire to monitor product quality and safety. The European blood legislation has defined several key quality elements to achieve good manufacturing practice in the field of blood transfusion. In addition, GMP/GLP and ISO standards are used inter alia by blood establishments. Following the call for proposal in the field of public health by the European Commission, a consortium of blood establishments from 16 European member, acceding and EFTA states has been established in order to survey the individual quality management systems used by the participants and to developed guidelines for quality systems. These guidelines are aimed at assisting blood establishments in preparing for government inspections as required by Directive 2002/98/EC. They could also be used to adapt existing procedures to comply with current EU requirements and/or to prepare for accreditation and certification of these institutions. Major benefits from those quality management systems are (1) the definition of an overall quality policy, (2) improved personnel responsibility, qualification and training, (3) error and risk assessment system, (4) continuous improvement, (5) improved resource management, (6) performance improvement. The definition of cost–benefit relation between certification and accreditation of blood establishments will depend on the individual institution itself and the amount of processes covered. With the release of the new EU Directive 2005/62/EC, there are currently EU requirements available that describe in detail relevant processes to be covered by quality system following good practice used in blood establishments. A future challenge for transfusion medicine would be optimizing the synergetic effects expressed by the EU directive, GMP and ISO standards.
Hepatitis B and blood transfusion
Authors: Roth W. K.
Published: June 2007

Hepatitis B is caused by infection with pandemic hepatitis B virus (HBV) and has a serious impact on blood safety worldwide. Active immunization is an efficient preventive measure particularly in countries with medium and high HBV prevalence. However, as long as only some countries have started immunization programmes for their younger population and escape mutants occur, stringent donor selection and testing is presently the only approach to reduce the risk of transfusion transmitted HBV infections. Surrogate testing for alanine aminotransferase (ALT) has shown its limitations and has mostly been discontinued especially since sensitivity and specificity of hepatitis B surface antigen (HBsAg) tests have been continuously improved. However, there remains a significant risk by donations from freshly infected donors who have not yet developed detectable HBsAg levels and donations by donors with occult infection that are HBsAg‐negative but HBV DNA‐positive. Nucleic acids amplification technology (NAT) has been applied primarily to close the diagnostic window between HBV infection and HBsAg detection and has shown to be effective either in testing donor samples in mini‐pools or by individual donation (ID) testing. It has also been shown that mini‐pool NAT may not be sufficiently sensitive to identify occult chronic carriers who show very low virus concentrations in their plasma. For those chronically infected donors, highly sensitive mini‐pool NAT with specific enrichment procedures and ID NAT may be required. Anti‐HBc testing would be the most sensitive approach resulting in highest yield rates for occult carriers. However, for medium and high prevalence countries, deferral rates would be extremely high with negative effects on the blood supply. Inactivation would be a reasonable alternative but at very high costs and is presently not applicable to all blood components. Future scenarios will most probably be diverse, depending on the prevalence in a given country, its resources and the vaccination status of its population.
Effect of hypoxia on fatigue development in rat muscle composed of different fibre types
Authors: Howlett Richard A. , Hogan Michael C.
Published: June 2007

This study investigated the relationship between hypoxia and the rate of fatigue development in contracting rat hindlimb muscles composed primarily of different fibre types. Hindlimb muscles of 11 rats were exposed, and the soleus (SOL) and gastrocnemius/plantaris (GP) were each isolated with circulation intact and attached to individual force transducers. Rats were then equilibrated with either normoxic (N; arterial partial pressure of O2 87.7 ± 1.5 mmHg) or hypoxic conditions (H; arterial partial pressure of O2 30.0 ± 2.4 mmHg) using an inspired O2 fraction of 0.21 and 0.10, respectively. The stimulation protocol consisted of 2 min each at 0.125, 0.25, 0.33 and 0.5 tetanic contractions s−1 sequentially for both conditions. Following the 8 min stimulation period, relative developed muscle tension (% of maximal) was nearly identical for both H and N in SOL (54.2 ± 3.5 versus 54.3 ± 4.2%), but was significantly (P < 0.05) lower in H than N (10.8 ± 0.9 versus 43.0 ± 8.9%) in GP, indicating a greater amount of fatigue during hypoxia only in the GP. Soleus phosphocreatine (PCr) content fell to similar levels (24.1 ± 1.6 versus 21.1 ± 4.9 mmol (kg dry weight (dw))−1) during both H and N, but in the white portion of the gastrocnemius (WG), PCr was significantly lower following H than N (14.3 ± 1.5 versus 34.0 ± 6.0 mmol (kg dw)−1). Similarly, muscle lactate increased in both fibre types at fatigue, but only in WG was the increase significantly greater with H (SOL 7.1 ± 2.0 versus 5.3 ± 1.1 mmol (kg dw)−1; WG 13.7 ± 4.5 versus 5.3 ± 2.2 mmol (kg dw)−1). Increases in calculated muscle [H+], free ADP and free AMP were similar between N and H in SOL but were significantly greater during H compared with N in WG. These data demonstrate that hypoxia induces greater fatigue and disruption of cellular homeostasis in rat hindlimb muscle composed primarily of fibres with low oxidative capacity compared with those of a more oxidative type.
Role of vascular bed compliance in vasomotor control in human skeletal muscle
Authors: Zamir M. , Goswami R. , Salzer D. , Shoemaker J. K.
Published: June 2007

The current view of neurogenic vasomotor control in skeletal muscle is based largely on changes in vascular bed resistance. The purpose of this study was to determine to what extent vascular bed compliance may also play a role in this regulation. For this purpose, pressure waveforms (Millar and Finometer) and flow waveforms (Doppler ultrasound) were measured simultaneously in the brachial artery of seven healthy individuals during physiological manoeuvres which were expected to produce non‐neurogenic changes in resistance (wrist‐cuff occlusion; n= 5) or compliance (arm elevation; n= 6) of the forearm vascular bed. Vascular resistance (R) was calculated from the average flow and pressure values. A lumped Windkessel model was used to obtain vascular bed compliance (C) from these concurrently measured waveforms. Compared with baseline (3.81 ± 1.59 ml min−1 mmHg−1), wrist occlusion increased R (65 ± 75%; P < 0.05) with minimal change in C (−15 ± 16%; n.s.). Compared with the arm in neutral position (0.0075 ± 0.003 ml mmHg−1), elevation of the arm above heart level produced a 86 ± 41% increase in C (P < 0.05) with little change in R (−5 ± 11%). In addition, neurogenic changes were assessed during lower body negative pressure (LBNP) and a cold pressor test (CPT; n= 7). Lower body negative pressure induced a 29 ± 24% increase in R and a 26 ± 12% decrease in C (both P < 0.05). The CPT induced no consistent change in R but a 22 ± 7% reduction in C (P < 0.05). It was concluded that vascular bed compliance is an independent variable which should be considered along with vascular bed resistance in the mechanics of vasomotor regulation in skeletal muscle.
Formate as an Auxiliary Substrate for Glucose-Limited Cultivation of
Penicillium chrysogenum
: Impact on Penicillin G Production and Biomass Yield
Authors: Harris Diana M. , van der Krogt Zita A. , van Gulik Walter M. , van Dijken Johannes P. , Pronk Jack T.
Published: June 2007

Production of β-lactams by the filamentous fungus
Penicillium chrysogenum
requires a substantial input of ATP. During glucose-limited growth, this ATP is derived from glucose dissimilation, which reduces the product yield on glucose. The present study has investigated whether penicillin G yields on glucose can be enhanced by cofeeding of an auxiliary substrate that acts as an energy source but not as a carbon substrate. As a model system, a high-producing industrial strain of
P. chrysogenum
was grown in chemostat cultures on mixed substrates containing different molar ratios of formate and glucose. Up to a formate-to-glucose ratio of 4.5 mol·mol
−1
, an increasing rate of formate oxidation via a cytosolic NAD
+
-dependent formate dehydrogenase increasingly replaced the dissimilatory flow of glucose. This resulted in increased biomass yields on glucose. Since at these formate-to-glucose ratios the specific penicillin G production rate remained constant, the volumetric productivity increased. Metabolic modeling studies indicated that formate transport in
P. chrysogenum
does not require an input of free energy. At formate-to-glucose ratios above 4.5 mol·mol
−1
, the residual formate concentrations in the cultures increased, probably due to kinetic constraints in the formate-oxidizing system. The accumulation of formate coincided with a loss of the coupling between formate oxidation and the production of biomass and penicillin G. These results demonstrate that, in principle, mixed-substrate feeding can be used to increase the yield on a carbon source of assimilatory products such as β-lactams.
Control of
Mycosphaerella graminicola
on Wheat Seedlings by Medical Drugs Known To Modulate the Activity of ATP-Binding Cassette Transporters
Authors: Roohparvar Ramin , Huser Aurelie , Zwiers Lute-Harm , De Waard Maarten A.
Published: June 2007

Medical drugs known to modulate the activity of human ATP-binding cassette (ABC) transporter proteins (modulators) were tested for the ability to potentiate the activity of the azole fungicide cyproconazole against in vitro growth of
Mycosphaerella graminicola
and to control disease development due to this pathogen on wheat seedlings. In vitro modulation of cyproconazole activity could be demonstrated in paper disk bioassays. Some of the active modulators (amitriptyline, flavanone, and phenothiazines) increased the accumulation of cyproconazole in
M. graminicola
, suggesting that they reversed cyproconazole efflux. However, synergism between cyproconazole and modulators against
M. graminicola
on wheat seedlings could not be shown. Despite their low in vitro toxicity to
M. graminicola
, some modulators (amitriptyline, loperamide, and promazine) did show significant intrinsic disease control activity in preventive and curative foliar spray tests with wheat seedlings. The results suggest that these compounds have indirect disease control activity based on modulation of fungal ABC transporters essential for virulence and constitute a new class of disease control agents.
Effect of Nutrient Starvation on the Cellular Composition and Metabolic Capacity of
Saccharomyces cerevisiae
Authors: Albers Eva , Larsson Christer , Andlid Thomas , Walsh Michael C. , Gustafsson Lena
Published: June 2007

This investigation addresses the following question: what are the important factors for maintenance of a high catabolic capacity under various starvation conditions?
Saccharomyces cerevisiae
was cultured in aerobic batch cultures, and during the diauxic shift cells were transferred and subjected to 24 h of starvation. The following conditions were used: carbon starvation, nitrogen starvation in the presence of glucose or ethanol, and both carbon starvation and nitrogen starvation. During the starvation period changes in biomass composition (including protein, carbohydrate, lipid, and nucleic acid contents), metabolic activity, sugar transport kinetics, and the levels of selected enzymes were recorded. Subsequent to the starvation period the remaining catabolic capacity was measured by addition of 50 mM glucose. The results showed that the glucose transport capacity is a key factor for maintenance of high metabolic capacity in many, but not all, cases. The results for cells starved of carbon, carbon and nitrogen, or nitrogen in the presence of glucose all indicated that the metabolic capacity was indeed controlled by the glucose transport ability, perhaps with some influence of hexokinase, phosphofructokinase, aldolase, and enolase levels. However, it was also demonstrated that there was no such correlation when nitrogen starvation occurred in the presence of ethanol instead of glucose.
Phylogenetic and Metabolic Diversity of
Planctomycetes
from Anaerobic, Sulfide- and Sulfur-Rich Zodletone Spring, Oklahoma
Authors: Elshahed Mostafa S. , Youssef Noha H. , Luo Qingwei , Najar Fares Z. , Roe Bruce A. , Sisk Tracy M. , Bühring Solveig I. , Hinrichs Kai-Uwe , Krumholz Lee R.
Published: June 2007

We investigated the phylogenetic diversity and metabolic capabilities of members of the phylum
Planctomycetes
in the anaerobic, sulfide-saturated sediments of a mesophilic spring (Zodletone Spring) in southwestern Oklahoma. Culture-independent analyses of 16S rRNA gene sequences generated using
Planctomycetes
-biased primer pairs suggested that an extremely diverse community of
Planctomycetes
is present at the spring. Although sequences that are phylogenetically affiliated with cultured heterotrophic
Planctomycetes
were identified, the majority of the sequences belonged to several globally distributed, as-yet-uncultured
Planctomycetes
lineages. Using complex organic media (aqueous extracts of the spring sediments and rumen fluid), we isolated two novel strains that belonged to the
Pirellula-Rhodopirellula-Blastopirellula
clade within the
Planctomycetes
. The two strains had identical 16S rRNA gene sequences, and their closest relatives were isolates from Kiel Fjord (Germany), Keauhou Beach (HI), a marine aquarium, and tissues of marine organisms (
Aplysina
sp. sponges and postlarvae of the giant tiger prawn
Penaeus monodon
). The closest recognized cultured relative of strain Zi62 was
Blastopirellula marina
(93.9% sequence similarity). Detailed characterization of strain Zi62 revealed its ability to reduce elemental sulfur to sulfide under anaerobic conditions, as well as its ability to produce acids from sugars; both characteristics may potentially allow strain Zi62 to survive and grow in the anaerobic, sulfide- and sulfur-rich environment at the spring source. Overall, this work indicates that anaerobic metabolic abilities are widely distributed among all major
Planctomycetes
lineages and suggests carbohydrate fermentation and sulfur reduction as possible mechanisms employed by heterotrophic
Planctomycetes
for growth and survival under anaerobic conditions.
Genetic Diversity of Rhizobia Associated with
Acacia longifolia
in Two Stages of Invasion of Coastal Sand Dunes
Authors: Rodríguez-Echeverría Susana , Crisóstomo João A. , Freitas Helena
Published: June 2007

We examined the genetic diversity of root nodule bacteria associated with the Australian legume
Acacia longifolia
in two stages of invasion of a coastal sand dune system. All isolates belonged to the genus
Bradyrhizobium.
A higher diversity was found in the long-established trees. The results suggest the introduction of exotic bradyrhizobia with the plant.
Germination of
Bacillus cereus
Spores Is Induced by Germinants from Differentiated Caco-2 Cells, a Human Cell Line Mimicking the Epithelial Cells of the Small Intestine
Authors: Wijnands L. M. , Dufrenne J. B. , van Leusden F. M. , Abee T.
Published: June 2007

Spores of 11 enterotoxigenic strains of
Bacillus cereus
isolated from foods and humans adhered with similar efficiencies to Caco-2 cells, whereas subsequent germination triggering was observed with only 8 of these strains. Notably, Hep-2 cells did not trigger germination, while spores of all strains displayed similar germination efficiencies in brain heart infusion broth.
Mutual Dependence of
Candida albicans
Est1p and Est3p in Telomerase Assembly and Activation
Authors: Hsu Min , Yu Eun Young , Singh Sunitha M. , Lue Neal F.
Published: June 2007

Telomerase is an RNA-protein complex responsible for extending one strand of the telomere terminal repeats. Analysis of the telomerase complex in budding yeasts has revealed the presence of one catalytic protein subunit (Est2p/TERT) and at least two noncatalytic components (Est1p and Est3p). The TERT subunit is essential for telomerase catalysis, while the functions of Est1p and Est3p have not been precisely elucidated. In an earlier study, we showed that telomerase derived from a
Candida est1
-null mutant is defective in primer utilization in vitro; it exhibits reduced initiation and processivity on primers that terminate in two regions of the telomere repeat. Here we show that telomerase derived from a
Candida est3
-null mutant has nearly identical defects in primer utilization and processivity. Further analysis revealed an unexpected mutual dependence of Est1p and Est3p in their assembly into the full telomerase complex, which accounts for the similarity between the mutant enzymes. We also developed an affinity isolation and an in vitro reconstitution protocol for the telomerase complex that will facilitate future mechanistic studies.
Identification and Characterization ofCPS1as a Hyaluronic Acid Synthase Contributing to the Pathogenesis ofCryptococcus neoformansInfection
Authors: Jong Ambrose , Wu Chun-Hua , Chen Han-Min , Luo Feng , Kwon-Chung Kyung J. , Chang Yun C. , LaMunyon Craig W. , Plaas Anna , Huang Sheng-He
Published: June 2007

Cryptococcus neoformansis a pathogenic yeast that often causes devastating meningoencephalitis in immunocompromised individuals. We have previously identified theC. neoformans CPS1gene, which is required for a capsular layer on the outer cell wall. In this report, we investigate the function of theCPS1gene and its pathogenesis. We demonstrated that treatment of yeast with either 4-methylumbelliferone or hyaluronidase resulted in a reduction of the level ofC. neoformansbinding to human brain microvascular endothelial cells (HBMEC). Yeast extracellular structures were also altered accordingly in hyaluronidase-treated cells. Furthermore, observation of yeast strains with different hyaluronic acid contents showed that the ability to bind to HBMEC is proportional to the hyaluronic acid content. A killing assay withCaenorhabditis elegansdemonstrated that theCPS1wild-type strain is more virulent than thecps1Δ strain. WhenCPS1is expressed inSaccharomyces cerevisiaeandEscherichia coli, hyaluronic acid can be detected in the cells. Additionally, we determined by fluorophore-assisted carbohydrate electrophoretic analysis that hyaluronic acid is a component of theC. neoformanscapsule. The size of hyaluronic acid molecules is evaluated by gel filtration and transmission electron microscopy studies. Together, our results support thatC. neoformans CPS1encodes hyaluronic acid synthase and that its product, hyaluronic acid, plays a role as an adhesion molecule during the association of endothelial cells with yeast.
Trichoderma atroviride
PHR1, a Fungal Photolyase Responsible for DNA Repair, Autoregulates Its Own Photoinduction
Authors: Berrocal-Tito Gloria M. , Esquivel-Naranjo Edgardo U. , Horwitz Benjamin A. , Herrera-Estrella Alfredo
Published: June 2007

The photolyases, DNA repair enzymes that use visible and long-wavelength UV light to repair cyclobutane pyrimidine dimers (CPDs) created by short-wavelength UV, belong to the larger photolyase-cryptochrome gene family. Cryptochromes (UVA-blue light photoreceptors) lack repair activity, and sensory and regulatory roles have been defined for them in plants and animals. Evolutionary considerations indicate that cryptochromes diverged from CPD photolyases before the emergence of eukaryotes. In prokaryotes and lower eukaryotes, some photolyases might have photosensory functions.
phr1
codes for a class I CPD photolyase in
Trichoderma atroviride. phr1
is rapidly induced by blue and UVA light, and its photoinduction requires functional blue light regulator (BLR) proteins, which are White Collar homologs in
Trichoderma
. Here we show that deletion of
phr1
abolished photoreactivation of UVC (200 to 280 nm)-inhibited spores and thus that PHR1 is the main component of the photorepair system. The 2-kb 5′ upstream region of
phr1
, with putative light-regulated elements, confers blue light regulation on a reporter gene. To assess
phr1
photosensory function, fluence response curves of this light-regulated promoter were tested in null mutant (Δ
phr1
) strains. Photoinduction of the
phr1
promoter in Δ
phr1
strains was >5-fold more sensitive to light than that in the wild type, whereas in PHR1-overexpressing lines the sensitivity to light increased about 2-fold. Our data suggest that PHR1 may regulate its expression in a light-dependent manner, perhaps through negative modulation of the BLR proteins. This is the first evidence for a regulatory role of photolyase, a role usually attributed to cryptochromes.
Crystal Structures of the Receiver Domain of the Response Regulator PhoP from
Escherichia coli
in the Absence and Presence of the Phosphoryl Analog Beryllofluoride
Authors: Bachhawat Priti , Stock Ann M.
Published: June 2007

The response regulator PhoP is part of the PhoQ/PhoP two-component system involved in responses to depletion of extracellular Mg
2+
. Here, we report the crystal structures of the receiver domain of
Escherichia coli
PhoP determined in the absence and presence of the phosphoryl analog beryllofluoride. In the presence of beryllofluoride, the active receiver domain forms a twofold symmetric dimer similar to that seen in structures of other regulatory domains from the OmpR/PhoB family, providing further evidence that members of this family utilize a common mode of dimerization in the active state. In the absence of activating agents, the PhoP receiver domain crystallizes with a similar structure, consistent with the previous observation that high concentrations can promote an active state of PhoP independent of phosphorylation.
Cell-Wide Responses to Low-Oxygen Exposure inDesulfovibrio vulgarisHildenborough
Authors: Mukhopadhyay Aindrila , Redding Alyssa M. , Joachimiak Marcin P. , Arkin Adam P. , Borglin Sharon E. , Dehal Paramvir S. , Chakraborty Romy , Geller Jil T. , Hazen Terry C. , He Qiang , Joyner Dominique C. , Martin Vincent J. J. , Wall Judy D. , Yang Zamin Koo , Zhou Jizhong , Keasling Jay D.
Published: June 2007

The responses of the anaerobic, sulfate-reducing organismDesulfovibrio vulgarisHildenborough to low-oxygen exposure (0.1% O2) were monitored via transcriptomics and proteomics. Exposure to 0.1% O2caused a decrease in the growth rate without affecting viability. Concerted upregulation of the predicted peroxide stress response regulon (PerR) genes was observed in response to the 0.1% O2exposure. Several of the candidates also showed increases in protein abundance. Among the remaining small number of transcript changes was the upregulation of the predicted transmembrane tetraheme cytochromec3complex. Other known oxidative stress response candidates remained unchanged during the low-O2exposure. To fully understand the results of the 0.1% O2exposure, transcriptomics and proteomics data were collected for exposure to air using a similar experimental protocol. In contrast to the 0.1% O2exposure, air exposure was detrimental to both the growth rate and viability and caused dramatic changes at both the transcriptome and proteome levels. Interestingly, the transcripts of the predicted PerR regulon genes were downregulated during air exposure. Our results highlight the differences in the cell-wide responses to low and high O2levels inD. vulgarisand suggest that while exposure to air is highly detrimental toD. vulgaris, this bacterium can successfully cope with periodic exposure to low O2levels in its environment.
Deletion of theparA(soj) Homologue inPseudomonas aeruginosaCauses ParB Instability and Affects Growth Rate, Chromosome Segregation, and Motility
Authors: Lasocki Krzysztof , Bartosik Aneta A. , Mierzejewska Jolanta , Thomas Christopher M. , Jagura-Burdzy Grazyna
Published: June 2007

TheparAandparBgenes ofPseudomonas aeruginosaare located approximately 8 kb anticlockwise fromoriC. ParA is a cytosolic protein present at a level of around 600 molecules per cell in exponential phase, but the level drops about fivefold in stationary phase. Overproduction of full-length ParA or the N-terminal 85 amino acids severely inhibits growth ofP. aeruginosaandP. putida. Both inactivation ofparAand overexpression ofparAintransinP. aeruginosaalso lead to accumulation of anucleate cells and changes in motility. Inactivation ofparAalso increases the turnover rate (degradation) of ParB. This may provide a mechanism for controlling the level of ParB in response to the growth rate and expression of theparABoperon.