bluuebunny/crossref_metadata_2025 huggingface dataset:
Relationships among rat numbers, abundance of oil palm fruit and damage levels to fruit in an oil palm plantation
Authors: PUAN Chong Leong , GOLDIZEN Anne W. , ZAKARIA Mohamed , HAFIDZI Mohd N. , BAXTER Greg S.
Published: June 2011

The relationships between vertebrate pests and crop damage are often complex and difficult to study. In palm oil plantations rodents remain the major pests, causing substantial monetary losses. The present study examined the numerical and functional responses of rodents to changes in the availability of oil palm fruit and the damage associated with that response. For the study, 200 traps were set in pairs on a 10 × 10 trapping grid for 3 consecutive nights in each of 6 study plots at 8‐week intervals in a 2569 ha oil palm plantation at Labu, Negeri Sembilan state in Peninsular Malaysia over 14 months. A total of 1292 individual rats were captured over 25 200 trap‐nights. Animals were identified, aged, sexed, weighed and measured. An index of the relative abundance of rats was calculated based on trapping success. Damage to infructescences was assessed at each trap point. Regardless of the age of palms, there were positive and significant relationships between the relative abundance of rats and numbers of infructescences. The levels of damage to infructescences were significantly correlated with the relative abundance of rats. A steep increase in damage was observed with an increase in mature infructescences, indicating a feeding preference of rats for mature infructescences. For both males and females of all rat species, there were weak and non‐significant correlations between body condition and infructescence numbers. These results indicated that there was a numerical and a functional response by rats to the availability of palm fruit and a resulting increase in depredation of oil palm fruits. The ways in which this information might aid in future pest control are discussed.
The neuroevolution of empathy
Authors: Decety Jean
Published: June 2011

There is strong evidence that empathy has deep evolutionary, biochemical, and neurological underpinnings. Even the most advanced forms of empathy in humans are built on more basic forms and remain connected to core mechanisms associated with affective communication, social attachment, and parental care. Social neuroscience has begun to examine the neurobiological mechanisms that instantiate empathy, especially in response to signals of distress and pain, and how certain dispositional and contextual moderators modulate its experience. Functional neuroimaging studies document a circuit that responds to the perception of others’ distress. Activation of this circuit reflects an aversive response in the observer, and this information may act as a trigger to inhibit aggression or prompt motivation to help. Moreover, empathy in humans is assisted by other domain‐general high‐level cognitive abilities, such as executive functions, mentalizing, and language, which expand the range of behaviors that can be driven by empathy.
Social isolation
Authors: Cacioppo John T. , Hawkley Louise C. , Norman Greg J. , Berntson Gary G.
Published: June 2011

Social species, by definition, form organizations that extend beyond the individual. These structures evolved hand in hand with behavioral, neural, hormonal, cellular, and genetic mechanisms to support them because the consequent social behaviors helped these organisms survive, reproduce, and care for offspring sufficiently long that they too reproduced. Social isolation represents a lens through which to investigate these behavioral, neural, hormonal, cellular, and genetic mechanisms. Evidence from human and nonhuman animal studies indicates that isolation heightens sensitivity to social threats (predator evasion) and motivates the renewal of social connections. The effects of perceived isolation in humans share much in common with the effects of experimental manipulations of isolation in nonhuman social species: increased tonic sympathetic tonus and HPA activation; and decreased inflammatory control, immunity, sleep salubrity, and expression of genes regulating glucocorticoid responses. Together, these effects contribute to higher rates of morbidity and mortality in older adults.
Prognostic significance of PaO2/PaCO2 ratio in normotensive patients with pulmonary embolism
Authors: Ozsu Savas , Abul Yasin , Yilmaz Ismail , Ozsu Asiye , Oztuna Funda , Bulbul Yilmaz , Ozlu Tevfik
Published: June 2011

Introduction:  Risk stratification remains controversial in patients with normotensive pulmonary embolism (PE). The debate has recently focused right ventricular dysfunction detected by echocardiography or spiral computed tomography (CT) and cardiac biomarkers.

Objectives:  The utility of the PaO2/PaCO2 ratio to predict the short‐term prognosis of PE is not currently known and that is the aim of the present study.

Materials and Methods:  This study retrospectively enrolled 99 (34 males, 65 females, 67 ± 15 years) consecutive patients with acute PE, diagnosed by spiral chest tomography pulmonary angiography (CTPA).On admission, cardiac troponin T (cTn‐T) was measured and on CTPA both right ventricle diameter and left ventricle diameter was calculated (RV/LV ratio). During the first 24 h after admission, all the patients had initial arterial blood gas collected under room air. Receiver‐operating characteristic (ROC) analysis was performed to determine the optimal PaO2/PaCO2, RV/LV ratio and cTn‐T cutoff level with regard to prognosis.

Results:  In‐hospital mortality was 12.1% and all‐cause 90‐day mortality was 15.2%. Ten of 15 patients who died had a PaO2/PaCO2 ≤ 1.8 based on ROC analysis (P < 0.014).The cutoff level of PaO2/PaCO2 ≤ 1.8 had a high negative predictive value of 93% for mortality. Multivariable analysis revealed that PaO2/PaCO2 ≤ 1.8 Hazard Ratio (HR): 16.8 [95% CI: 2.6–108, P < 0.003] was the most significant independent predictor, whereas cTn‐T, pO2 < 60 mmHg and cardiac failure were nonsignificant factors. In addition, PaO2/PaCO2 ≤ 1.8 showed significant survival differences for overall mortality rates in Kaplan–Meier analysis (P < 0.012).

Conclusion:  The PaO2/PaCO2 measurement is a highly useful and practical measurement to predict prognosis in patients with acute PE. Moreover, it appears to be a more accurate predictor than RV/LV ratio and cTn‐T levels in patients with normotensive PE.

Please cite this paper as: Ozsu S, Abul Y, Yilmaz I, Ozsu A, Oztuna F, Bulbul Y and Ozlu T. Prognostic significance of PaO2/PaCO2 ratio in normotensive patients with pulmonary embolism. Clin Respir J 2012; 6: 104–111.
The prevalence of chronic obstructive pulmonary disease in Uppsala, Sweden – the Burden of Obstructive Lung Disease (BOLD) study: cross‐sectional population‐based study
Authors: Danielsson Patrik , Ólafsdóttir Inga Sif , Benediktsdóttir Bryndis , Gíslason Thórarinn , Janson Christer
Published: June 2011

Objectives:  To estimate chronic obstructive pulmonary disease (COPD) prevalence in Uppsala and the impact of risk factors on disease prevalence using the standardised methods of the Burden of Obstructive Lung Disease (BOLD) study initiative.

Methods:  Randomly selected participants, aged 40 years or more (n = 548) responded to a questionnaire regarding smoking habits, respiratory symptoms, medical history, and exposure to airway irritants. Spirometry, with a post‐bronchodilator test, was performed and COPD defined as post‐bronchodilatory forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) < 0.70 or FEV1/FVC < lower limit of normality (LLN). Circulatory inflammatory markers were measured.

Results:  COPD prevalence was 16.2%, which was the fourth lowest prevalence of COPD, compared with 12 other BOLD centres. Main risk factors for COPD were increasing age [odds ratio (OR) = 2.08 per 10 years] and smoking (OR = 1.33 per 10 pack years). Higher education was protective (OR = 0.70 per 5 years). Previous tuberculosis was an almost significant risk factor for COPD (P = 0.08). Subjects with COPD reported more respiratory symptoms but only 29% had previous doctor diagnosed COPD, asthma, chronic bronchitis or emphysema. Participants with COPD had higher levels of C‐reactive protein (P = 0.01), but no difference was observed in interleukin 6 (IL‐6) levels. Using LLN instead of the fixed FEV1/FVC ratio reduced the prevalence of COPD to 10%.

Conclusion:  COPD prevalence in Uppsala was similar to other BOLD centres in high‐income countries. Apart from known COPD risk factors (age, smoking, lower educational level), a history of tuberculosis may be associated with COPD even in high‐income countries. COPD remains under‐diagnosed, as only 29% of subjects with COPD had a previously diagnosed lung disorder.

Please cite this paper as: Danielsson P, Ólafsdóttir IS, Benediktsdóttir B, Gíslason T and Janson C. The prevalence of chronic obstructive pulmonary disease in Uppsala, Sweden – the Burden of Obstructive Lung Disease (BOLD) study: cross‐sectional population‐based study. Clin Respir J 2012; 6: 120–127.
Risk Factors for Human Rabies in China
Authors: Gong Z. , He F. , Chen Z.
Published: June 2011

In China, we have witnessed an increasing incidence of rabies in recent years and the number of deaths ranked first among the 39 notifiable infectious diseases. We conducted a case–control study to identify risk factors for human rabies infection and disease to recommend prevention and treatment among people exposed to rabies. Exposure site, pre‐exposure prophylaxis and post‐exposure prophylaxis were significantly associated with rabies infection. Exposure site at upper limb and trunk or at lower limb were at lower risk as compared with head‐exposed patients. The OR was 0.09(95% CI: 0.009–0.93) and 0.01(95% CI: 0.001–0.115) respectively. Pre‐exposure prophylaxis (OR = 0.05, 95% CI: 0.03–0.11) and post‐exposure prophylaxis (OR = 0.02, 95% CI: 0.01–0.40) were both protective factors as compared with no prophylaxis. For patients who had post‐exposure prophylaxis, dose for the first injection and immunity procedure were significantly associated with rabies infection.
Impact of fusion to Gαi2 and co-expression with RGS proteins on pharmacological properties of human cannabinoid receptors CB1R and CB2R
Authors: Sutor Sarah , Heilmann Jörg , Seifert Roland
Published: June 2011

Objectives

G protein coupled receptor (GPCR)-Gα fusion proteins are often employed to investigate receptor/G protein interaction. In this study, the impact of Gα fusion proteins on pharmacology of CBRs, both mediating signals through Gαi proteins, were investigated. Gαi2 was fused to the C-terminus of the CBRs or co-expressed with non-fused Gαi2 in Sf9 cells, always together with Gβ1γ2. Furthermore, the impact of RGS proteins on CBR signaling in combination with the CBR fusion approach was examined, using RGS4 and RGS19 as paradigms.

Methods

CBR ligands were characterized in the steady-state GTPase assay and pharmacological properties of ligands in the different test systems were correlated.

Key findings

Fusion of CBRs to Gαi2 enhanced the maximal stimulatory effects of ligands compared to the co-expression system, especially for CB2R. RGS4, but not RGS19, behaved as a GTPase-activating protein at CBRs in the Gαi2 co-expression and fusion system. Fusion of GPCR, most prominently CB2R, to Gαi2, and co-expression with RGS4 altered the pharmacological properties of ligands.

Conclusions

Our data suggest that fusion of CB2R to Gαi2 and co-expression with RGS4 impedes with conformational changes. Moreover, our results support the concept of ligand-specific receptor conformations. Finally, this paper describes the most sensitive CBR test system currently available.
Application of hydrotropy to transdermal formulations: hydrotropic solubilization of polyol fatty acid monoesters in water and enhancement effect on skin permeation of 5-FU
Authors: Takahashi Koichi , Komai Megumi , Kinoshita Natsumi , Nakamura Emi , Hou Xiao-Long , Takatani-Nakase Tomoka , Kawase Masaya
Published: June 2011

Objectives

A hydrotropic formulation containing a percutaneous enhancer was developed for the transdermal formulation of a water-soluble drug and the solubilizing mechanisms of a percutaneous enhancer in water by a hydrotropic agent were investigated. The enhancement effect was also compared with the hydrotropic formulation and the other formulations using ethanol, propylene glycol or mixed micelles.

Methods

Sodium salicylate (SA) and sodium benzoate (BA) were selected as hydrotropic agents, and polyol fatty acid ester (POFE) and 5-fluorouracil (5-FU) were selected as a percutaneous enhancer and a water-soluble drug, respectively. Near-infrared (NIR) spectrophotometric and 1H NMR spectroscopic studies were carried out to investigate the solubilizing mechanisms. The mean particle size in the hydrotropic formulation was measured. The in-vitro skin permeation of 5-FU and the accumulation in the skin of propylene glycol monocaprylate (PGMC), one of the monoesters of POFE, from the hydrotropic formulation or the other formulations were investigated by using Franz-type diffusion cell.

Key findings

The presence of SA and BA had a visible effect on the O–H stretching band of water in the NIR region. The surface tension of SA and BA aqueous solutions was found to decrease with an increase in SA or BA concentration. Although SA interacted with PGMC in the presence of water, it did not interact with PGMC in the absence of water. Mean particle size in a solution consisting of 5% (v/v) PGMC and 30% SA aqueous solution was approximately 14 nm. 1H NMR spectroscopic studies indicated that the hydrotropic salts formed aggregates with which PGMC interacted from the outside. The hydrotropic formulation prepared in this study enhanced skin permeation of 5-FU when compared with the other formulations.

Conclusions

SA and BA solubilized monoesters of POFE in water, and SA interacted with PGMC in water. The hydrotropic formulation prepared in this study significantly enhanced skin permeation of 5-FU compared with the other formulations. The results suggest that a hydrotropic formulation containing PGMC may be a useful transdermal formulation for water-soluble drugs.
Cytotoxic evaluation and induction of mitochondria-mediated apoptosis in human leukaemia HL-60 cells by Carissa spinarum stem isolate
Authors: Sehar Irum , Pal Harish Chandra , Shukla Sangeeta , Bhushan Shashi , Hamid Abid , Gupta Bishan Dutt , Saxena Ajit Kumar
Published: June 2011

Objective

To evaluate Carissa spinarum stem isolate for its anti-cancer therapeutic potential.

Methods

The n-butanol fraction of aqueous extract from Carissa spinarum stem was assessed for its cytotoxic and pro-apoptotic activity.

Key findings

We report for the first time the anti-cancer potential of C. spinarum stem aqueous extract (CSE) and its n-butanol fraction (CSF). Both inhibited cell proliferation of various human cancer cell lines in which leukaemia HL-60 cells treated with CSF showed maximum growth inhibition having an inhibitory concentration (IC50) value of 34.58 ± 0.91 µg/ml. In addition, CSF induced concentration-dependent apoptosis in HL-60 cells as measured by various end-points (e.g. Annexin V binding, DNA laddering, apoptotic body formation and an increase in hypodiploid subG0 DNA content). Moreover, persistent levels of reactive oxygen species caused translocation of Bax to mitochondria and Bcl-2 degradation, which led to loss of mitochondrial membrane potential and release of cytochrome c to the cytosol. These events were associated with significant activation of caspase-3, caspase-6 and caspase-9 leading to poly (ADP-ribose) polymerase cleavage.

Conclusion

All the above parameters revealed that CSF induced apoptosis through the mitochondrial dependent pathway in HL-60 cells.
Inhibition of ketamine-induced hyperlocomotion in mice by the essential oil of Alpinia zerumbet: possible involvement of an antioxidant effect
Authors: de Araújo Fernanda Yvelize Ramos , de Oliveira Gersilene Valente , Gomes Patrícia Xavier Lima , Soares Marília Almeida , Silva Maria Izabel Gomes , Carvalho André Férrer , de Moraes Manoel Odorico , de Moraes Maria Elisabete Amaral , Vasconcelos Silvânia Maria Mendes , Viana Glauce Socorro Barros , de Sousa Francisca Cléa Florenço , Macêdo Danielle Silveira
Published: June 2011

Objectives

The antipsychotic, hypnotic, myorelaxant and antioxidant effects of the essential oil of Alpinia zerumbet (EOAZ) were studied.

Methods

EOAZ (50, 100 and 200 mg/kg i.p.) was administered once to mice for the determination of antipsychotic activity (evaluated by ketamine-induced hyperlocomotion), hypnotic activity (induced by sodium pentobarbital, 40 mg/kg i.p.), motor coordination (rotarod test), antioxidant effects (determination of lipid peroxidation and GSH levels), as well as alterations in nitric oxide levels (determination of nitrite content).

Key findings

EOAZ at doses of 100 and 200 mg/kg prevented ketamine hyperlocomotion, as did haloperidol (0.2 mg/kg i.p). EOAZ at a dose of 200 mg/kg decreased sleep latency, while all doses increased sleeping time. There was no effect on motor coordination. The in-vitro antioxidant capacity of the oil caused a decrease in lipid peroxidation and increase in GSH levels. EOAZ also prevented the decrease in nitrite content caused by oxidative stress.

Conclusions

The results suggest antipsychotic and antioxidant effects for the EOAZ that may have promising efficacy for the treatment of schizophrenia.
The Instantaneous Efficiency of Epicyclic Gears in Flight Control Systems
Authors: Wang Anngwo , Gitnes Seth , El-Bayoumy Lotfi
Published: June 2011

The instantaneous efficiency of an epicyclic gear rotary actuator is an important factor in sizing flight control systems where compound epicyclic gear trains are typically used. The efficiency variation can be smooth or fluctuating depending on the combination and timing of the teeth of ring, planet, and sun gears. In this paper, the instantaneous efficiency characteristics of synchronous and nonsynchronous actuators under forward-driving with opposing load and reverse-driving with aiding load are investigated. The emphasis will be on instantaneous, rather than average efficiency of gears. Several gear arrangements are considered: external and internal gears, simple planetary gears and compound planetary gears. Efficiency will be discussed considering not only the geometry of the mating gears, but also the relative phasing of the planet gears relative to the sun and ring gears. Synchronous compound epicyclic gears are shown to have large fluctuation in their instantaneous efficiency. When reverse-driving efficiency falls below 0%, the unit cannot be back-driven and will chatter. Nonsynchronous compound gears have a smaller variation in instantaneous efficiency. However, extra care must be taken in timing the compound planet gears, as well as clocking position of compound planet gears relative to ring gears and the sun gear.
Energy Based Functional Decomposition in Preliminary Design
Authors: Pailhès Jérôme , Sallaou Mohammed , Nadeau Jean-Pierre , Fadel Georges M.
Published: June 2011

This paper presents an energy based approach to functional decomposition that is applicable to the top down design (system to subsystems to components) of mechanical systems. The paper shows that the main functions of convert and transmit are sufficient to focus on the “functional flow” or main energy flow resulting in the specific action sought as a result of the artifact being designed, and can be expanded upon at the lowest level when looking for specific solutions based upon the energy and mass balances and the knowledge within the design team. This approach considers function as a transformation and also fits the approach presented in TRIZ. The standard energy, material, and signal flows are seen as forms of energy flows, and it is only their transformation and transmission that is sought. This simplified approach, coupled with an aspect of control and interaction between a reference state and the artifact or between various components is sufficient to comprehensively describe the system that matches very nicely the value function approach of Miles. Furthermore, as these interactions can be considered as artifact-artifact affordances when considering the artifact for either artifact interaction or within an environment, its relation to the user and to the reference state can be addressed during the design phase, in addition to the functions.
Submerged Conidiation and Product Formation by Aspergillus niger at Low Specific Growth Rates Are Affected in Aerial Developmental Mutants
Authors: Jørgensen Thomas R. , Nielsen Kristian F. , Arentshorst Mark , Park JooHae , van den Hondel Cees A. , Frisvad Jens C. , Ram Arthur F.
Published: June 2011

Exposure to an aerial environment or severe nutrient limitation induces asexual differentiation in filamentous fungi. Submerged cultivation of
Aspergillus niger
in carbon- and energy-limited retentostat cultures both induces and fuels conidiation. Physiological and transcriptomic analyses have revealed that this differentiation strongly affects product formation. Since conidiation is inherent in the aerial environment, we hypothesized that product formation near zero growth can be influenced by affecting differentiation or development of aerial hyphae in general. To investigate this idea, three developmental mutants (Δ
fwnA
,
scl-1
, and
scl-2
mutants) that have no apparent vegetative growth defects were cultured in maltose-limited retentostat cultures. The secondary-metabolite profile of the wild-type strain defined flavasperone, aurasperone B, tensidol B, and two so far uncharacterized compounds as associated with conidium formation, while fumonisins B
2
, B
4
, and B
6
were characteristic of early response to nutrient limitation by the vegetative mycelium. The developmental mutants responded differently to the severe substrate limitation, which resulted in distinct profiles of growth and product formation.
fwnA
encodes the polyketide synthase responsible for melanin biosynthesis during aerial differentiation, and we show that conidial melanin synthesis in submerged retentostat cultures and aurasperone B production are
fwnA
dependent. The
scl-1
and
scl-2
strains are two UV mutants generated in the Δ
fwnA
background that displayed reduced asexual conidiation and formed sclerotium-like structures on agar plates. The reduced conidiation phenotypes of the
scl-1
and
scl-2
strains are reflected in the retentostat cultivation and are accompanied by elimination or severely reduced accumulation of secondary metabolites and distinctly enhanced accumulation of extracellular protein. This investigation shows that submerged conidiation and product formation of a mitosporic fungus cultured at low specific growth rates can be fundamentally affected by interfering with the genetic program for differentiation of aerial hyphae, opening new perspectives for tailoring industrial performance.
Comparison of Innovative Molecular Approaches and Standard Spore Assays for Assessment of Surface Cleanliness
Authors: Cooper Moogega , La Duc Myron T. , Probst Alexander , Vaishampayan Parag , Stam Christina , Benardini James N. , Piceno Yvette M. , Andersen Gary L. , Venkateswaran Kasthuri
Published: June 2011

A bacterial spore assay and a molecular DNA microarray method were compared for their ability to assess relative cleanliness in the context of bacterial abundance and diversity on spacecraft surfaces. Colony counts derived from the NASA standard spore assay were extremely low for spacecraft surfaces. However, the PhyloChip generation 3 (G3) DNA microarray resolved the genetic signatures of a highly diverse suite of microorganisms in the very same sample set. Samples completely devoid of cultivable spores were shown to harbor the DNA of more than 100 distinct microbial phylotypes. Furthermore, samples with higher numbers of cultivable spores did not necessarily give rise to a greater microbial diversity upon analysis with the DNA microarray. The findings of this study clearly demonstrated that there is not a statistically significant correlation between the cultivable spore counts obtained from a sample and the degree of bacterial diversity present. Based on these results, it can be stated that validated state-of-the-art molecular techniques, such as DNA microarrays, can be utilized in parallel with classical culture-based methods to further describe the cleanliness of spacecraft surfaces.
Marine Isolates of Trichoderma spp. as Potential Halotolerant Agents of Biological Control for Arid-Zone Agriculture
Authors: Gal-Hemed Inbal , Atanasova Lea , Komon-Zelazowska Monika , Druzhinina Irina S. , Viterbo Ada , Yarden Oded
Published: June 2011

The scarcity of fresh water in the Mediterranean region necessitates the search for halotolerant agents of biological control of plant diseases that can be applied in arid-zone agriculture irrigated with saline water. Among 29
Trichoderma
strains previously isolated from Mediterranean
Psammocinia
sp. sponges, the greatest number of isolates belong to the
Trichoderma longibrachiatum
-
Hypocrea orientalis
species pair (9),
H. atroviridis/T. atroviride
(9), and
T. harzianum
species complex (7), all of which are known for high mycoparasitic potential. In addition, one isolate of
T. asperelloides
and two putative new species,
Trichoderma
sp. O.Y. 14707 and O.Y. 2407, from Longibrachiatum and Strictipilosa clades, respectively, have been identified.
In vitro
salinity assays showed that the ability to tolerate increasing osmotic pressure (halotolerance) is a strain- or clade-specific property rather than a feature of a species. Only a few isolates were found to be sensitive to increased salinity, while others either were halotolerant or even demonstrated improved growth in increasingly saline conditions.
In vitro
antibiosis assays revealed strong antagonistic activity toward phytopathogens due to the production of both soluble and volatile metabolites. Two marine-derived
Trichoderma
isolates, identified as
T. atroviride
and
T. asperelloides
, respectively, effectively reduced
Rhizoctonia solani
damping-off disease on beans and also induced defense responses in cucumber seedlings against
Pseudomonas syringae
pv. lachrimans. This is the first inclusive evaluation of marine fungi as potential biocontrol agents.
Identification and Characterization of UndA
HRCR-6
, an Outer Membrane Endecaheme
c
-Type Cytochrome of Shewanella sp. Strain HRCR-6
Authors: Shi Liang , Belchik Sara M. , Wang Zheming , Kennedy David W. , Dohnalkova Alice C. , Marshall Matthew J. , Zachara John M. , Fredrickson James K.
Published: June 2011

UndA
HRCR-6
was identified from the metal-reducing bacterium
Shewanella
sp. strain HRCR-6. Both
in vivo
and
in vitro
characterization results indicate that UndA
HRCR-6
is an outer membrane endecaheme
c
-type cytochrome and probably has a key functional role in the extracellular reduction of iron [Fe(III)] oxides and uranium [U(VI)] by
Shewanella
sp. HRCR-6.
Natural Competence and Recombination in the Plant Pathogen Xylella fastidiosa
Authors: Kung Stephanie H. , Almeida Rodrigo P. P.
Published: June 2011

Homologous recombination is one of many forces contributing to the diversity, adaptation, and emergence of pathogens. For naturally competent bacteria, transformation is one possible route for the acquisition of novel genetic material. This study demonstrates that
Xylella fastidiosa
, a generalist bacterial plant pathogen responsible for many emerging plant diseases, is naturally competent and able to homologously recombine exogenous DNA into its genome. Several factors that affect transformation and recombination efficiencies, such as nutrient availability, growth stage, and methylation of transforming DNA, were identified. Recombination was observed in at least one out of every 10
6
cells when exogenous plasmid DNA was supplied and one out of every 10
7
cells when different strains were grown together
in vitro
. Based on previous genomic studies and experimental data presented here, there is mounting evidence that recombination can occur at relatively high rates and could play a large role in shaping the genetic diversity of
X. fastidiosa
.
Interface of Candida albicans Biofilm Matrix-Associated Drug Resistance and Cell Wall Integrity Regulation
Authors: Nett Jeniel E. , Sanchez Hiram , Cain Michael T. , Ross Kelly M. , Andes David R.
Published: June 2011

Candida albicans
frequently infects medical devices by growing as a biofilm, i.e., a community of adherent organisms entrenched in an extracellular matrix. During biofilm growth,
Candida
spp. acquire the ability to resist high concentrations of antifungal drugs. One recently recognized biofilm resistance mechanism involves drug sequestration by matrix β-1,3 glucan. Using a candidate gene approach, we investigated potential
C. albicans
β-1,3-glucan regulators, based on their homology to
Saccharomyces cerevisiae
, including
SMI1
and protein kinase C (PKC) pathway components. We identified a role for the
SMI1
in biofilm matrix glucan production and development of the associated drug resistance phenotype. This pathway appears to act through transcription factor Rlmp and glucan synthase Fks1p. The phenotypes of these mutant biofilms mimicked those of the
smi1
Δ/
smi1
Δ biofilm, and overexpression of
FKS1
in the
smi1
Δ/
smi1
Δ mutant restored the biofilm resistant phenotype. However, control of this pathway is distinct from that of the upstream PKC pathway because the
pkc1
Δ/
pkc1
Δ,
bck1
Δ/
bck1
Δ,
mkk2
Δ/
mkk2
Δ, and
mkc1
Δ/
mkc1
Δ biofilms retained the resistant phenotype of the parent strain. In addition, resistance to cell-perturbing agents and gene expression data do not support a significant role for the cell wall integrity pathway during the biofilm formation. Here we show that Smi1p functions in conjunction with Rlm1p and Fks1p to produce drug-sequestering biofilm β-glucan. Our work provides new insight into how the
C. albicans
biofilm matrix production and drug resistance pathways intersect with the planktonic cell wall integrity pathway. This novel connection helps explain how pathogens in a multicellular biofilm community are protected from anti-infective therapy.
Uracil-DNA Glycosylase of Thermoplasma acidophilumDirects Long-Patch Base Excision Repair, Which Is Promoted by Deoxynucleoside Triphosphates and ATP/ADP, into Short-Patch Repair
Authors: Moen Marivi N. , Knævelsrud Ingeborg , Haugland Gyri T. , Grøsvik Kristin , Birkeland Nils-Kåre , Klungland Arne , Bjelland Svein
Published: June 2011

Hydrolytic deamination of cytosine to uracil in DNA is increased in organisms adapted to high temperatures. Hitherto, the uracil base excision repair (BER) pathway has only been described in two archaeons, the crenarchaeon
Pyrobaculum aerophilum
and the euryarchaeon
Archaeoglobus fulgidus
, which are hyperthermophiles and use single-nucleotide replacement. In the former the apurinic/apyrimidinic (AP) site intermediate is removed by the sequential action of a 5′-acting AP endonuclease and a 5′-deoxyribose phosphate lyase, whereas in the latter the AP site is primarily removed by a 3′-acting AP lyase, followed by a 3′-phosphodiesterase. We describe here uracil BER by a cell extract of the thermoacidophilic euryarchaeon
Thermoplasma acidophilum
, which prefers a similar short-patch repair mode as
A. fulgidus
. Importantly,
T. acidophilum
cell extract also efficiently executes ATP/ADP-stimulated long-patch BER in the presence of deoxynucleoside triphosphates, with a repair track of ∼15 nucleotides. Supplementation of recombinant uracil-DNA glycosylase (rTaUDG; ORF Ta0477) increased the formation of short-patch at the expense of long-patch repair intermediates, and additional supplementation of recombinant DNA ligase (rTalig; Ta1148) greatly enhanced repair product formation. TaUDG seems to recruit AP-incising and -excising functions to prepare for rapid single-nucleotide insertion and ligation, thus excluding slower and energy-costly long-patch BER.
Different Conformations of the Kinase-On and Kinase-Off Signaling States in the Aer HAMP Domain
Authors: Watts Kylie J. , Johnson Mark S. , Taylor Barry L.
Published: June 2011

HAMP domains are sensory transduction modules that connect input and output domains in diverse signaling proteins from archaea, bacteria, and lower eukaryotes. Here, we employedin vivodisulfide cross-linking to explore the structure of the HAMP domain in theEscherichia coliaerotaxis receptor Aer. Using an Aer HAMP model based on the structure ofArchaeoglobus fulgidusAf1503-HAMP, the closest residue pairs at the interface of the HAMP AS-1 and AS-2′ helices were determined and then replaced with cysteines and cross-linkedin vivo. Except for a unique discontinuity in AS-2, the data suggest that the Aer HAMP domain forms a parallel four-helix bundle that is similar to the structure of Af1503. The HAMP discontinuity was associated with a segment of AS-2 that was recently shown to interact with the Aer-PAS sensing domain. The four-helix HAMP bundle and its discontinuity were maintained in both the kinase-on and kinase-off states of Aer, although differences in the rates of disulfide formation also indicated the existence of different HAMP conformations in the kinase-on and kinase-off states. In particular, the kinase-on state was accompanied by significantly increased disulfide formation rates at the distal end of the HAMP four-helix bundle. This indicates that HAMP signaling may be associated with a tilting of the AS-1 and AS-2′ helices, which may be the signal that is transmitted to the kinase control region of Aer.
Taking the Escherichia coli TonB Transmembrane Domain “Offline”? Nonprotonatable Asn Substitutes Fully for TonB His20
Authors: Swayne Cheryl , Postle Kathleen
Published: June 2011

The TonB system of Gram-negative bacteria uses the proton motive force (PMF) of the cytoplasmic membrane to energize active transport of nutrients across the outer membrane. The single transmembrane domain (TMD) anchor of TonB, the energy transducer, is essential. Within that TMD, His20 is the only TMD residue that is unable to withstand alanine replacement without a loss of activity. H20 is required for a PMF-dependent conformational change, suggesting that the importance of H20 lies in its ability to be reversibly protonated and deprotonated. Here all possible residues were substituted at position 20 (H20X substitutions). The His residue was also relocated throughout the TonB TMD. Surprisingly, Asn, a structurally similar but nonprotonatable residue, supported full activity at position 20; H20S was very weakly active. All the remaining substitutions, including H20K, H20R, H20E, and H20D, the obvious candidates to mimic a protonated state or support proton translocation, were inactive. A second-site suppressor, ExbB(A39E), indiscriminately reactivated the majority of H20 substitutions and relocations, including H20V, which cannot be made protonatable. These results suggested that the TonB TMD was not on a proton conductance pathway and thus only indirectly responds to PMF, probably via ExbD.
Cryptococcus neoformans Requires a Functional Glycolytic Pathway for Disease but Not Persistence in the Host
Authors: Price Michael S. , Betancourt-Quiroz Marisol , Price Jennifer L. , Toffaletti Dena L. , Vora Haily , Hu Guanggan , Kronstad James W. , Perfect John R.
Published: June 2011

Cryptococcus neoformansis an important fungal pathogen of immunocompromised individuals, with a close relative,Cryptococcus gattii, emerging as a serious threat for the immunocompetent. During initial infection,C. neoformanscolonizes the airspaces of the lungs, resulting in pneumonia, and subsequently migrates to the central nervous system (CNS). We sought to understand fungal carbon utilization during colonization of these fundamentally different niches within the host, in particular the roles of gluconeogenesis and glycolysis. We created mutants at key points in the gluconeogenesis/glycolysis metabolic pathways that are restricted for growth on lactate and glucose, respectively. A phosphoenolpyruvate carboxykinase mutant (thepck1∆mutant), blocked for entry of 2- and 3-carbon substrates into gluconeogenesis and attenuated for virulence in a murine inhalation model, showed wild-type (WT) persistence in a rabbit cerebrospinal fluid (CSF) model of cryptococcosis. Conversely, both the pyruvate kinase (pyk1∆) and the hexose kinase I and II (hxk1∆/hxk2∆) mutants, which show impaired glucose utilization, exhibited severely attenuated virulence in the murine inhalation model of cryptococcosis and decreased persistence in the CNS in both the rabbit CSF and the murine inhalation models while displaying adequate persistence in the lungs of mice. These data suggest that glucose utilization is critical for virulence ofC. neoformansand persistence of the yeast in the CNS.

IMPORTANCECryptococcus neoformansis an emerging fungal pathogen of humans and is responsible for approximately 625,000 deaths annually among those suffering from HIV infection/AIDS. The ability of this fungus to persist in the host, coupled with its propensity to colonize the CNS, makes the understanding of nutrient acquisition in the host a primary concern. In this study, we report a requirement of glucose utilization for virulence ofC. neoformansthat is separate from its role in ATP production in the pathogen. Furthermore, we show that inhibition of glycolysis is a viable antifungal drug target, and impaired ATP production via thePYK1deletion may serve as a model for dormant/chronic fungal infection in the host. Taken together, these results demonstrate the critical importance of understanding basic metabolic processes of the fungus in the context of host-pathogen interactions.
Fertility and whelping complications in bitches following correction of vaginal abnormalities
Authors: Moxon R. , England G. C. W.
Published: June 2011

The fertility and whelping complications of normal bitches and of bitches that had had surgery to correct a vaginal abnormality of varying severities were compared retrospectively. Reproductive performance and whelping statistics were compared between 37 bitches that had been diagnosed with a vaginal abnormality and 37 age‐ and breed‐matched bitches with no history of vaginal abnormalities. There were no significant differences in reproductive performance between the affected and control bitches. When analysed by the severity of the abnormality, pregnancy rates were significantly lower for the group of bitches with the most severe abnormalities compared with the group of bitches that had mild vaginal abnormalities. Furthermore, the bitches that had severe abnormalities were significantly more likely to require a caesarean section than those with mild abnormalities.
RECURRENT TWO-DIMENSIONAL SEQUENCES GENERATED BY HOMOMORPHISMS OF FINITE ABELIAN p-GROUPS WITH PERIODIC INITIAL CONDITIONS
Authors: PRUNESCU MIHAI
Published: June 2011

We prove that if a recurrent two-dimensional sequence with periodic initial conditions coincides in a sufficiently large starting square with a two-dimensional sequence produced by an expansive system of context-free substitutions, then they must coincide everywhere. We apply this result for some examples built up by homomorphisms of finite abelian p-groups, in particular for Pascal's Triangle modulo pk, Pascal's Triangles modulo 2 with non-trivial periodic borders, and Sierpinski's Carpets with non-trivial periodic border. All these particular cases justify the conjecture that recurrent two-dimensional sequences generated by homomorphisms of finite abelian p-groups with periodic initial conditions can always be alternatively generated by expansive systems of context-free substitutions.
Preparation of99mTc(CO)3-TPPS4and its biological behavior evaluation
Authors: Yang Yuqing , Song Hu , Song Hongtao , Zhao Weiwei , Pu Manfei
Published: June 2011

99mTc(CO)3-TPPS4was prepared via the precursor [99mTc(CO)3(H2O)3]+and a preliminary investigation on its stability and behavior in Hep2 tumor cells and hepatoma-bearing mice were conducted. Labeling yield and stability of99mTc(CO)3-TPPS4was radioactively analyzed by paper chromatography. Hep2 tumor cells were incubated with99mTc(CO)3-TPPS4complex system in the substrate and isolated from the substrate for radioactivity count. Then99mTc(CO)3-TPPS4complex system was intravenously injected in hepatoma-bearing mice and directly injected in tumor tissue of the mice. Mice were photographed using SPECT. Labeling yields of99mTc(CO)3-TPPS4were more than 90% at pH = 7–8, 30 min, in a boiling bath, and it was stable for at least 14 h at pH = 2–8, rt ~95 °C. The uptake of99mTc(CO)3-TPPS4in HepG2 tumor cells was only 3–4% with the maximum uptake-time of 20 min. The SPECT images of hepatoma-bearing nude mice showed no uptake or little retention of99mTc(CO)3-TPPS4in the tumor tissue. Then the differences between99mTc(CO)3-TPPS4and TPPS4were analyzed by fluoroscopy and molecular structure. It was found that the paper chromatography, HepG2 tumor cell uptake and the optimized porphyrin ring conformation of99mTc(CO)3-TPPS4were quite different from those of TPPS4. It was indicated that99mTc(CO)3-TPPS4had no uptake or little retention in hepatic tumors, unlike those biological behaviors of TPPS4. This may be due to the modification of porphyrin ring conformation of TPPS4by99mTc(CO)3core.
cGMP phosphodiesterase inhibition improves the vascular and metabolic actions of insulin in skeletal muscle
Authors: Genders A. J. , Bradley E. A. , Rattigan S. , Richards S. M.
Published: June 2011

There is considerable support for the concept that insulin-mediated increases in microvascular blood flow to muscle impact significantly on muscle glucose uptake. Since the microvascular blood flow increases with insulin have been shown to be nitric oxide-dependent inhibition of cGMP-degrading phosphodiesterases (cGMP PDEs) is predicted to enhance insulin-mediated increases in microvascular perfusion and muscle glucose uptake. Therefore, we studied the effects of the pan-cGMP PDE inhibitor zaprinast on the metabolic and vascular actions of insulin in muscle. Hyperinsulinemic euglycemic clamps (3 mU·min−1·kg−1) were performed in anesthetized rats and changes in microvascular blood flow assessed from rates of 1-methylxanthine metabolism across the muscle bed by capillary xanthine oxidase in response to insulin and zaprinast. We also characterized cGMP PDE isoform expression in muscle by real-time PCR and immunostaining of frozen muscle sections. Zaprinast enhanced insulin-mediated microvascular perfusion by 29% and muscle glucose uptake by 89%, while whole body glucose infusion rate during insulin infusion was increased by 33% at 2 h. PDE2, -9, and -10 were the major isoforms expressed at the mRNA level in muscle, while PDE1B, -9A, -10A, and -11A proteins were expressed in blood vessels. Acute administration of the cGMP PDE inhibitor zaprinast enhances muscle microvascular blood flow and glucose uptake response to insulin. The expression of a number of cGMP PDE isoforms in skeletal muscle suggests that targeting specific cGMP PDE isoforms may provide a promising avenue for development of a novel class of therapeutics for enhancing muscle insulin sensitivity.
SPARC regulates collagen interaction with cardiac fibroblast cell surfaces
Authors: Harris Brett S. , Zhang Yuhua , Card Lauren , Rivera Lee B. , Brekken Rolf A. , Bradshaw Amy D.
Published: June 2011

Cardiac tissue from mice that do not express secreted protein acidic and rich in cysteine (SPARC) have reduced amounts of insoluble collagen content at baseline and in response to pressure overload hypertrophy compared with wild-type (WT) mice. However, the cellular mechanism by which SPARC affects myocardial collagen is not clearly defined. Although expression of SPARC by cardiac myocytes has been detected in vitro, immunohistochemistry of hearts demonstrated SPARC staining primarily associated with interstitial fibroblastic cells. Primary cardiac fibroblasts isolated from SPARC-null and WT mice were assayed for collagen I synthesis by [3H]proline incorporation into procollagen and by immunoblot analysis of procollagen processing. Bacterial collagenase was used to discern intracellular from extracellular forms of collagen I. Increased amounts of collagen I were found associated with SPARC-null versus WT cells, and the proportion of total collagen I detected on SPARC-null fibroblasts without propeptides [collagen-α1(I)] was higher than in WT cells. In addition, the amount of total collagen sensitive to collagenase digestion (extracellular) was greater in SPARC-null cells than in WT cells, indicating an increase in cell surface-associated collagen in the absence of SPARC. Furthermore, higher levels of collagen type V, a fibrillar collagen implicated in collagen fibril initiation, were found in SPARC-null fibroblasts. The absence of SPARC did not result in significant differences in proliferation or in decreased production of procollagen I by cardiac fibroblasts. We conclude that SPARC regulates collagen in the heart by modulating procollagen processing and interactions with fibroblast cell surfaces. These results are consistent with decreased levels of interstitial collagen in the hearts of SPARC-null mice being due primarily to inefficient collagen deposition into the extracellular matrix rather than to differences in collagen production.
Comparative gene responses to collected ambient particles in vitro: endothelial responses
Authors: Aung Hnin H. , Lame Michael W. , Gohil Kishorchandra , He Guochun , Denison Michael S. , Rutledge John C. , Wilson Dennis W.
Published: June 2011

Epidemiologic studies associate exposure to ambient particulate matter (APM) with increased cardiovascular mortality. Since both pulmonary inflammation and systemic circulation of ultrafine particles are hypothesized as initiating cardiovascular effects, we examined responses of potential target cells in vitro. Human aortic endothelial cells (HAEC) were exposed to 10 μg/ml fine and ultrafine APM collected in an urban setting in summer 2006 or winter 2007 in the San Joaquin Valley, California. RNA isolated after 3 h was analyzed with high-density oligonucleotide arrays. Summer APM treatment affected genes involved in xenobiotic and oxidoreductase activity, transcription factors, and inflammatory responses in HAEC, while winter APM had a robust xenobiotic but lesser inflammatory response. Real-time polymerase chain reaction analysis confirmed that particulate matter (PM)-treated HAEC increased mRNA levels of xenobiotic response enzymes CYP1A1, ALDH1A3, and TIPARP and cellular stress response transcription factor ATF3. Inflammatory response genes included E-selectin, PTGS2, CXCL-2 (MIP-2α), and CCL-2 (MCP-1). Multiplex protein assays showed secretion of IL-6 and MCP-1 by HAEC. Since induction of CYP1A1 is mediated through the ligand-activated aryl hydrocarbon receptor (AhR), we demonstrated APM induced AhR nuclear translocation by immunofluorescence and Western blotting and activation of the AhR response element using a luciferase reporter construct. Inhibitor studies suggest differential influences of polycyclic aromatic hydrocarbon signaling, ROS-mediated responses and endotoxin alter stress and proinflammatory endothelial cell responses. Our findings demonstrate gene responses correlated with current concepts that systemic inflammation drives cardiovascular effects of particulate air pollution. We also demonstrate a unique pattern of gene responses related to xenobiotic metabolism in PM-exposed HAEC.