bluuebunny/crossref_metadata_2025 huggingface dataset:
A CTG Clade Candida Yeast Genetically Engineered for the Genotype-Phenotype Characterization of Azole Antifungal Resistance in Human-Pathogenic Yeasts
Authors: Accoceberry Isabelle , Rougeron Amandine , Biteau Nicolas , Chevrel Pauline , Fitton-Ouhabi Valérie , Noël Thierry
Published: October 2017

A strain of the opportunistic pathogenic yeast
Candida lusitaniae
was genetically modified for use as a cellular model for assessing by allele replacement the impact of lanosterol C14α-demethylase
ERG11
mutations on azole resistance.
Candida lusitaniae
was chosen because it is susceptible to azole antifungals, it belongs to the CTG clade of yeast, which includes most of the
Candida
species pathogenic for humans, and it is haploid and easily amenable to genetic transformation and molecular modeling. In this work, allelic replacement is targeted at the
ERG11
locus by the reconstitution of a functional auxotrophic marker in the 3′ intergenic region of
ERG11
. Homologous and heterologous
ERG11
alleles are expressed from the resident
ERG11
promoter of
C. lusitaniae
, allowing accurate comparison of the phenotypic change in azole susceptibility. As a proof of concept, we successfully expressed in
C. lusitaniae
different
ERG11
alleles, either bearing or not bearing mutations retrieved from a clinical context, from two phylogenetically distant yeasts,
C. albicans
and
Kluyveromyces marxianus
.
Candida lusitaniae
constitutes a high-fidelity expression system, giving specific Erg11p-dependent fluconazole MICs very close to those observed with the
ERG11
donor strain. This work led us to characterize the phenotypic effect of two kinds of mutation: mutation conferring decreased fluconazole susceptibility in a species-specific manner and mutation conferring fluconazole resistance in several yeast species. In particular, a missense mutation affecting amino acid K143 of Erg11p in
Candida
species, and the equivalent position K151 in
K. marxianus
, plays a critical role in fluconazole resistance.
Potency of Meropenem-Vaborbactam in Lung Surfactant
Authors: Rubio-Aparicio Debora , Loutit Jeff , Dudley Michael , Lomovskaya Olga
Published: October 2017

This study investigated whether pulmonary surfactant has an effect on the
in vitro
antibacterial activity of either meropenem alone or meropenem in combination with vaborbactam at a fixed concentration of 8 μg/ml against several
Klebsiella pneumoniae
carbapenemase (KPC)-producing strains of Gram-negative bacteria. Results showed that the potency of meropenem alone and that of meropenem-vaborbactam were not affected when tested with pulmonary surfactant.
A Systematic Review and Meta-analyses of the Clinical Epidemiology of Carbapenem-Resistant Enterobacteriaceae
Authors: van Loon Karlijn , Voor in ‘t holt Anne F. , Vos Margreet C.
Published: October 2017

Carbapenem-resistantEnterobacteriaceae(CRE) are major health care-associated pathogens and responsible for hospital outbreaks worldwide. To prevent a further increase in CRE infections and to improve infection prevention strategies, it is important to summarize the current knowledge about CRE infection prevention in hospital settings. This systematic review aimed to identify risk factors for CRE acquisition among hospitalized patients. In addition, we summarized the environmental sources/reservoirs and the most successful infection prevention strategies related to CRE. A total of 3,983 potentially relevant articles were identified and screened. Finally, we included 162 studies in the systematic review, of which 69 studies regarding risk factors for CRE acquisition were included in the random-effects meta-analysis studies. The meta-analyses regarding risk factors for CRE acquisition showed that the use of medical devices generated the highest pooled estimate (odds ratio [OR] = 5.09; 95% confidence interval [CI] = 3.38 to 7.67), followed by carbapenem use (OR = 4.71; 95% CI = 3.54 to 6.26). To control hospital outbreaks, bundled interventions, including the use of barrier/contact precautions for patients colonized or infected with CRE, are needed. In addition, it is necessary to optimize the therapeutic approach, which is an important message to infectious disease specialists, who need to be actively involved in a timely manner in the treatment of patients with known CRE infections or suspected carriers of CRE.
Urinary Tract Conditions Affect Fosfomycin Activity against Escherichia coli Strains Harboring Chromosomal Mutations Involved in Fosfomycin Uptake
Authors: Martín-Gutiérrez G. , Docobo-Pérez F. , Rodriguez-Beltrán J. , Rodríguez-Martínez J. M. , Aznar J. , Pascual A. , Blázquez J.
Published: October 2017

The steps by which
Escherichia coli
strains harboring mutations related to fosfomycin (FOS) resistance arise and spread during urinary tract infections (UTIs) are far from being understood. The aim of this study was to evaluate the effects of urine, pH, and anaerobiosis on FOS activity against a set of isogenic strains carrying the most prevalent chromosomal mutations conferring FOS resistance (Δ
uhpT
, Δ
glpT
, Δ
cyaA
, and Δ
ptsI
), either singly or in combination. We also studied fosfomycin-resistant
E. coli
clinical isolates from patients with UTI. Our results demonstrate that urinary tract physiological conditions might have a profound impact on FOS activity against strains with chromosomal FOS resistance mutations. Specifically, acidic pH values and anaerobiosis convert most of the strains categorized as resistant to fosfomycin according to the international guidelines to a susceptible status. Therefore, urinary pH values may have practical interest in the management of UTIs. Finally, our results, together with the high fitness cost associated with FOS resistance mutations, might explain the low prevalence of fosfomycin-resistant
E. coli
variants in UTIs.
Microbial Composition Predicts Genital Tract Inflammation and Persistent Bacterial Vaginosis in South African Adolescent Females
Authors: Lennard Katie , Dabee Smritee , Barnabas Shaun L. , Havyarimana Enock , Blakney Anna , Jaumdally Shameem Z. , Botha Gerrit , Mkhize Nonhlanhla N. , Bekker Linda-Gail , Lewis David A. , Gray Glenda , Mulder Nicola , Passmore Jo-Ann S. , Jaspan Heather B.
Published: October 2017

Young African females are at an increased risk of HIV acquisition, and genital inflammation or the vaginal microbiome may contribute to this risk. We studied these factors in 168 HIV-negative South African adolescent females aged 16 to 22 years. Unsupervised clustering of 16S rRNA gene sequences revealed three clusters (subtypes), one of which was strongly associated with genital inflammation. In a multivariate model, the microbiome compositional subtype and hormonal contraception were significantly associated with genital inflammation. We identified 40 taxa significantly associated with inflammation, including those reported previously (Prevotella,Sneathia,Aerococcus,Fusobacterium, andGemella) as well as several novel taxa (including increased frequencies of bacterial vaginosis-associated bacterium 1 [BVAB1], BVAB2, BVAB3,Prevotella amnii,Prevotella pallens,Parvimonas micra,Megasphaera,Gardnerella vaginalis, andAtopobium vaginaeand decreased frequencies ofLactobacillus reuteri,Lactobacillus crispatus,Lactobacillus jensenii, andLactobacillus iners). Women with inflammation-associated microbiomes had significantly higher body mass indices and lower levels of endogenous estradiol and luteinizing hormone. Community functional profiling revealed three distinct vaginal microbiome subtypes, one of which was characterized by extreme genital inflammation and persistent bacterial vaginosis (BV); this subtype could be predicted with high specificity and sensitivity based on the Nugent score (≥9) or BVAB1 abundance. We propose that women with this BVAB1-dominated subtype may have chronic genital inflammation due to persistent BV, which may place them at a particularly high risk for HIV infection.
Lactobacillus rhamnosus L34 Attenuates Gut Translocation-Induced Bacterial Sepsis in Murine Models of Leaky Gut
Authors: Panpetch Wimonrat , Chancharoenthana Wiwat , Bootdee Kanthika , Nilgate Sumanee , Finkelman Malcolm , Tumwasorn Somying , Leelahavanichkul Asada
Published: October 2017

Gastrointestinal (GI) bacterial translocation in sepsis is well known, but the role of
Lactobacillus
species probiotics is still controversial. We evaluated the therapeutic effects of
Lactobacillus rhamnosus
L34 in a new sepsis model of oral administration of pathogenic bacteria with GI leakage induced by either an antibiotic cocktail (ATB) and/or dextran sulfate sodium (DSS). GI leakage with ATB, DSS, and DSS plus ATB (DSS+ATB) was demonstrated by fluorescein isothiocyanate (FITC)-dextran translocation to the circulation. The administration of pathogenic bacteria, either
Klebsiella pneumoniae
or
Salmonella enterica
serovar Typhimurium, enhanced translocation. Bacteremia was demonstrated within 24 h in 50 to 88% of mice with GI leakage plus the administration of pathogenic bacteria but not with GI leakage induction alone or bacterial gavage alone.
Salmonella
bacteremia was found in only 16 to 29% and 0% of mice with
Salmonella
and
Klebsiella
administrations, respectively.
Klebsiella
bacteremia was demonstrated in 25 to 33% and 10 to 16% of mice with
Klebsiella
and
Salmonella
administrations, respectively.
Lactobacillus rhamnosus
L34 attenuated GI leakage in these models, as shown by the reductions of FITC-dextran gut translocation, serum interleukin-6 (IL-6) levels, bacteremia, and sepsis mortality. The reduction in the amount of fecal
Salmonella
bacteria with
Lactobacillus
treatment was demonstrated. In addition, an anti-inflammatory effect of the conditioned medium from
Lactobacillus rhamnosus
L34 was also demonstrated by the attenuation of cytokine production in colonic epithelial cells
in vitro
. In conclusion,
Lactobacillus rhamnosus
L34 attenuated the severity of symptoms in a murine sepsis model induced by GI leakage and the administration of pathogenic bacteria.
Novel Gene Encoding 5-Aminosalicylate 1,2-Dioxygenase from Comamonas sp. Strain QT12 and Catalytic Properties of the Purified Enzyme
Authors: Yu Hao , Zhao Shuxue , Guo Lizhong
Published: October 2017

The 1,125-bp
mabB
gene encoding 5-aminosalicylate (5ASA) 1,2-dioxygenase, a nonheme iron dioxygenase in the bicupin family that catalyzes the cleavage of the 5ASA aromatic ring to form
cis
-4-amino-6-carboxy-2-oxohexa-3,5-dienoate in the biodegradation of 3-aminobenzoate, was cloned from
Comamonas
sp. strain QT12 and characterized. The deduced amino acid sequence of the enzyme has low sequence identity with that of other reported ring-cleaving dioxygenases. MabB was heterologously expressed in
Escherichia coli
cells and purified as a His-tagged enzyme. The optimum pH and temperature for MabB are 8.0 and 10°C, respectively. Fe
II
is required for the catalytic activity of the purified enzyme. The apparent

K
m

and
V
max
values of MabB for 5ASA are 52.0 ± 5.6 μM and 850 ± 33.2 U/mg, respectively. The two oxygen atoms incorporated into the product of the MabB-catalyzed reaction are both from the dioxygen molecule. Both 5ASA and gentisate could be converted by MabB; however, the catalytic efficiency of MabB for 5ASA was much higher (∼70-fold) than that for gentisate. The
mabB
-disrupted mutant lost the ability to grow on 3-aminobenzoate, and
mabB
expression was higher when strain QT12 was cultivated in the presence of 3-aminobenzoate. Thus, 5ASA is the physiological substrate of MabB.

IMPORTANCE
For several decades, 5-aminosalicylate (5ASA) has been advocated as the drug mesalazine to treat human inflammatory bowel disease and considered the key intermediate in the xenobiotic degradation of many aromatic organic pollutants. 5ASA biotransformation research will help us elucidate the microbial degradation of these pollutants. Most studies have reported that gentisate 1,2-dioxygenases (GDOs) can convert 5ASA with significantly high activity; however, the catalytic efficiency of these enzymes for gentisate is much higher than that for 5ASA. This study showed that MabB can convert 5ASA to
cis
-4-amino-6-carboxy-2-oxohexa-3,5-dienoate, incorporating two oxygen atoms from the dioxygen molecule into the product. Unlike GDOs, MabB uses 5ASA instead of gentisate as the primary substrate.
mabB
is the first reported 5-aminosalicylate 1,2-dioxygenase gene.
Characterization of Copy Number Control of Two Haloferax volcanii Replication Origins Using Deletion Mutants and Haloarchaeal Artificial Chromosomes
Authors: Maurer Sandy , Ludt Katharina , Soppa Jörg
Published: October 2017

Haloferax volcanii
is polyploid and contains about 20 genome copies under optimal conditions. However, the chromosome copy number is highly regulated and ranges from two during phosphate starvation to more than 40 under conditions of phosphate surplus. The aim of this study was the characterization of the influence of two replication origins on the genome copy number. The origin repeats and the genes encoding
o
rigin
r
ecognition
c
omplex (ORC) proteins were deleted. The core origin oriC1-
orc1
(ori1) deletion mutant had a lower genome copy number and a higher level of fitness than the wild type, in stark contrast to the oriC2-
orc5
(ori2) deletion mutant. The genes adjacent to ori1 could not be deleted, and thus, at least two of them are probably essential, while deletion of the genes adjacent to ori2 was possible. Various fragments of and around the origins were cloned into a suicide plasmid to generate
h
aloarchaeal
a
rtificial
c
hromosomes (HACs). The copy number of the oriC1-
orc1
HAC was much higher than that of the oriC2-
orc5
HAC. The addition of adjacent genes influenced both the HAC copy number and the chromosome copy number. The results indicate that the origins of
H. volcanii
are not independent but that the copy number is regulated via a network of genes around the origins.

IMPORTANCE
Several species of archaea have more than one origin of replication on their major chromosome and are thus the only known prokaryotic species that allow the analysis of the evolution of multiorigin replication. The widely studied
Haloferax volcanii
H26 strain has a major chromosome with four origins of replication. Two origins, ori1 and ori2, were chosen for an in-depth analysis using deletion mutants and haloarchaeal artificial chromosomes. The analysis was not restricted to the core origin regions; origin-adjacent genes were also included. Because
H. volcanii
is polyploid, the effects on the chromosome copy number were of specific importance. The results revealed extreme differences between the two origins.
Stigma among Singaporean youth: a cross-sectional study on adolescent attitudes towards serious mental illness and social tolerance in a multiethnic population
Authors: Pang Shirlene , Liu Jianlin , Mahesh Mithila , Chua Boon Yiang , Shahwan Shazana , Lee Siau Pheng , Vaingankar Janhavi Ajit , Abdin Edimansyah , Fung Daniel Shuen Sheng , Chong Siow Ann , Subramaniam Mythily
Published: October 2017

Objectives

Stigma against mental illnesses is one of the significant obstacles faced by mental health service users and providers. It can develop at a young age and is also influenced by culture. Youths in Southeast Asian countries are under-represented in mental health research, thus this study aims to explore the dimensions of stigma and social tolerance and examine its correlates in the younger, multiethnic population of Singapore.

Design

An online survey collected data with sociodemographic questions, the Attitudes Towards Serious Mental Illness (Adolescent version) Scale, Social Tolerance Scale and an open-text question on words or phrases participants associated with the term ‘mental illness’. Principal component analysis and multiple regression models were conducted to investigate the factor structure of the attitudes and social tolerance scales and their sociodemographic correlates.

Participants

Participants included 940 youths aged 14–18 years old who were residing in Singapore at the time of the survey and were recruited through local schools.

Results

About a quarter of the students (22.6%) reported participating in mental health awareness campaigns while nearly half (44.5%) associated pejorative words and phrases with the term mental illness. The Attitudes Towards Serious Mental Illness (Adolescent version) Scale yielded five factors while the Social Tolerance Scale yielded two. Ethnicity, gender and nationality were significantly correlated with factors of both scales. Chinese youths showed higher sense of ’physical threat' and lower ’social tolerance' than those of other ethnicities. Females showed more ’wishful thinking', ’social concern' and ’social responsibility' towards the mentally ill than males.

Conclusions

The dimensions of stigma and social tolerance are different in Asian cultures compared with Western cultures. Sociodemographic differences in attitudes towards the mentally ill were found among youths living in Singapore. Misconceptions and negative attitudes towards mental illness are common, demonstrating a clear need for effective stigma reduction campaigns.
Impact of internal carotid endarterectomy on visual fields: a non-randomised prospective cohort study in Austria
Authors: Konstantiniuk Peter , Steinbrugger Iris , Koter Stephan , Muehlsteiner Johanna , Wedrich Andreas , Cohnert Tina
Published: October 2017

Purpose

The goal of this study was to determine whether internal carotid endarterectomy is associated with visual field changes.

Methods

Between March 2007 and December 2010, a cohort study involved 29 patients with stenosis of the carotid artery. All patients underwent ophthalmoscopy and kinetic visual field examination (Goldmann perimetry) preoperatively and postoperatively. Furthermore, a detailed area calculation was performed. On both the operated and the contralateral side, the areas surrounded by the different isopters (isopter areas) were determined and preoperative and postoperative values compared. The three isopters were classified from the centre to the periphery (I, II and III). Isopter area values are given as ratio compared with total perimetric circle. p Values <0.05 were considered to be statistically significant.

Results

1) The ophthalmologists assessment

Eight of eleven patients with precarotid endarterectomy impairments experienced focal or concentric improvement. Six cases with preoperative concentric narrowing of the isopters returned to normal or improved substantially. Three out of 18 patients with normal preoperative visual field presented with deteriorations after surgery, two cases with ipsilateral and one with contralateral focal impairment. In 15 cases, there was no preoperative or postoperative abnormality.

2) Area calculation (preoperative area, postoperative area, P)

Ipsilateral: isopter area I (0.015, 0.018, 0.131), isopter area II (0.107, 0.120, 0.087), isopter area III (0.392, 0.425, 0.015)

Contralateral: isopter area I (0.017, 0.021, 0.222), isopter area II (0.119, 0.125, 0.333), isopter area III (0.416, 0.434, 0.171)

Conclusions

We found a statistically significant extension of the ipsilateral peripheral isopter area (III). Further studies will focus on the question which subgroup is most likely to profit from internal carotid endarterectomy with respect to visual field changes.
Synovial fibroblasts in 2017
Authors: Ospelt Caroline
Published: October 2017

Stromal cells like synovial fibroblasts gained great interest over the years, since it has become clear that they strongly influence their environment and neighbouring cells. The current review describes the role of synovial fibroblasts as cells of the innate immune system and expands on their involvement in inflammation and cartilage destruction in rheumatoid arthritis (RA). Furthermore, epigenetic changes in RA synovial fibroblasts and studies that focused on the identification of different subsets of synovial fibroblasts are discussed.
A randomized, controlled, crossover study of appetite-related sensations after consuming snacks made from buckwheat
Authors: Defries Danielle M. , Petkau Jay C. , Gregor Terri , Blewett Heather
Published: October 2017

With the rising incidence of overweight and obesity in developed countries, there is an interest in developing food products that may aid in satiety and reduce energy intake. Buckwheat (Fagopyrum esculentum) is a gluten-free edible seed that has been previously shown to induce changes in postprandial concentrations of satiety hormones; however, subjective measures of appetite-related sensations and objective measures of energy intake at subsequent meals following buckwheat consumption have not been measured. Thirty-eight healthy adults were recruited to participate in a randomized, controlled, crossover trial with the main objective to determine if consuming snacks made from buckwheat would increase satiety and reduce energy intake compared with snacks comparable in serving size, physical characteristics, and nutrient composition. Water was included as a no-kilocalorie control. Participants received each of the treatments once separated by at least 7 days. Appetite related sensations were assessed using visual analog scales at fasting and after consuming the snack at 30-min intervals for 180 min. Lunch was provided at the clinic and the amount of food consumed was weighed. Participants recorded food intake for the rest of the day. Consuming buckwheat groats (32 g serving; 141 kcal) or pita bread made from buckwheat flour (50 g serving; 135 kcal) was not associated with changes in appetite related sensations or energy consumption compared with reference snack products made from corn or rice flour. Sensory questionnaires revealed that snacks made from buckwheat were liked to a similar degree or more as reference snack products, which shows commercial promise for developing buckwheat-containing snacks.
Lamin A/C mutation associated with lipodystrophy influences adipogenic differentiation of stem cells through interaction with Notch signaling
Authors: Perepelina K. , Dmitrieva R. , Ignatieva E. , Borodkina A. , Kostareva A. , Malashicheva A.
Published: October 2017

Lamins A and C are involved in many cellular functions, owing to its ability to bind chromatin and transcription factors and affect their properties. Mutations of the LMNA gene encoding lamin A/C affect differentiation capacity of stem cells. However, the signaling pathways involved in interactions with lamins during cellular differentiation remain unclear. Lipodystrophy associated with LMNA mutation R482L causes loss of fat tissue. In this study we investigated the role of LMNA mutation R482L in modulating Notch signaling activity in the adipogenic differentiation of mesenchymal stem cells. Notch was activated using lentiviral Notch intracellular domain. Activation of Notch was estimated through the expression of Notch-responsive genes by qPCR and by activation of a luciferase CSL-reporter construct. The effect of LMNA mutation on Notch activation and adipogenic differentiation was analyzed in cells bearing lentiviral LMNA WT or LMNA R482L. We show that, when Notch is activated, LMNA R482L contributes to down-regulation of Notch activation in undifferentiated and differentiated cells, and decreases adipogenic differentiation. Thus, lamin A/C interacts with Notch signaling, thereby influencing cellular differentiation, and point mutation in LMNA could halt this interaction.
Magnetic and pebble fabrics of glaciomarine diamictons in the Champlain Sea, Ontario, Canada
Authors: Gravenor C. P.
Published: October 2017

Glaciomarine diamicton(ite)s that contain articulated unbroken shell remains are usually assumed to have been deposited by the settling out of suspended mud with additions of coarse clasts derived from the melting of debris-laden floating ice. However, little is known about the magnetic and pebble fabrics of these composite sediments, and the purpose of this study is to describe and interpret the magnetic and pebble fabrics of fossiliferous glaciomarine diamictons found at three locations in the Champlain Sea, Ontario.At two of the three sites examined it is found that the long axes of the prolate and blade-shaped pebbles do not show well defined alignments, but they are not randomly distributed in either the horizontal or vertical planes. This observation and an analysis of the alignment of the magnetic particles in the matrix of the diamictons show that the diamictons have undergone syn- or post-depositional movement and fall into the category of glaciogenic subaquatic debris flows. At the third site the diamictons are stratified, and the magnetic fabric and field evidence show that post-depositional movement was caused by loading of sand layers into underlying muds.The results suggest that magnetic fabrics can be useful in interpreting pebble fabrics and that the dual approach may help to differentiate various types of glaciomarine diamicton(ite)s.
Stream Migration of Yearling Splake (Salvelinus fontinalis × S. namaycush) Planted in Georgian Bay
Authors: Berst A. H. , Payne N. R.
Published: October 2017

Yearling splake (Salvelinus fontinalis × S. namaycush) (F4, F5) released into Georgian Bay in 1971 and 1972, when lake surface temperatures averaged 5.5 C lower than the hatchery temperature, tended to move into streams within 3.6 km of the planting site where temperatures approached the hatchery temperature and the temperature preferendum of the hybrid. This tendency was not apparent in splake planted at later dates when the lake and hatchery temperatures were similar. Varying stream flows had no discernible effect on the migration of splake into the study streams.
Attempts to induce homoeologous pairing between wheat and Agropyron cristatum genomes
Authors: Jubault Mélanie , Tanguy Anne-Marie , Abélard Paulette , Coriton Olivier , Dusautoir Jean-Claude , Jahier Joseph
Published: October 2017

Agropyron cristatum (2n = 4x = 28, PPPP) possesses potentially valuable traits that could be used in wheat (Triticum aestivum) improvement through interspecific hybridization. Homoeologous pairing between wheat chromosomes and P chromosomes added to wheat in a set of wheat – A. cristatum addition lines was assessed. First, the Ph-suppressing effect of P chromosomes (except 7P) was analyzed. It was concluded that this system is polygenic with no major gene, and consequently, has no prospect in the transfer of alien genes from wild relatives. In a second step, the potential of the deletion ph1b of the Ph1 gene for inducing P–ABD pairing was evaluated. Allosyndetic associations between P and ABD genomes are very rare. This very low level of pairing is likely due to divergence in the repeated sequences between Agropyron and wheat genomes. Development of translocation lines using ionizing radiation seems to be a more suitable technique than homoeologous recombination to exploit the A. cristatum genome in wheat improvement.Key words: Triticum aestivum, Agropyron cristatum, addition line, GISH, Ph1 gene.
Synthesis of the diborylated ferrocene 1,1'-bis-(bis-pentafluorophenylboryl)ferrocene and the X-ray structure of its trimethylphosphine adduct
Authors: Carpenter Bryon E , Piers Warren E , McDonald Robert
Published: October 2017

The diborylated ferrocene compound 1,1'-Fc[B(C6F5)2]2 (2) was prepared via a transmetallation reaction involving 1,1'-Fc(HgCl)2 and two equivalents of ClB(C6F5)2. Although this reaction is very clean spectroscopically, isolated yields of 2 were never greater than 40% owing to the high solubility of the compound in non-donor solvents. Compound 2 is similar in its properties to the related monoborylated complex FcB(C6F5)2 (1) reported previously, particularly the UVvis spectrum, which exhibits an intense charge transfer absorption (λmax = 233 nm, ε = 1.64 × 104) assignable to an Fe dz 2 / dx 2  y 2 [Formula: see text] Bp transition. However, 2, is significantly more Lewis acidic than 1, reacting with weak donors such as acetonitrile at room temperature, and effecting methide abstraction from Cp2ZrMe2 under mild conditions. Complex 2 also forms a bis(trimethylphosphine) adduct (3), which was structurally characterized via X-ray crystallography.Key words: organoboranes, ferrocene derivatives, multidentate Lewis acids.
NUTRITION OF ANIMAL CELLS IN TISSUE CULTURE: VIII. DESOXYRIBONUCLEIC ACID PHOSPHORUS AS A MEASURE OF CELL MULTIPLICATION IN REPLICATE CULTURES
Authors: Healy George M. , Fisher Dorothy C. , Parker Raymond C.
Published: October 2017

A chemical method of estimating the size of cell populations in replicate cultures has been devised for use with certain cell strains from the mouse and rat. The method is based upon the determination of desoxyribonucleic acid phosphorus (DNAP). Although the method may be used as an alternative to the procedure of counting isolated, stained nuclei in a hemocytometer, it actually supplements such measurements and provides useful information on the DNA-content per cell. The method consists of a modified Schmidt and Thannhauser separation of ribonucleic acid (RNA) and desoxyribonucleic acid (DNA) followed by the spectrophotometric estimation of the orthophosphate. The present communication describes the procedures in detail and reports recoveries of RNAP and DNAP from mixtures of highly polymerized nucleic acids and various types of biological material. Good correlation was found between nuclear counts and DNAP values in natural media (containing horse serum and chick embryo extract) and in synthetic (chemically-defined) media. Finally, the efficiency of the dispensing apparatus most frequently employed in preparing replicate cultures from continuously stirred, washed cell suspensions has been determined by measuring the DNAP content of serially dispensed samples.
INCORPORATION OF RADIOACTIVE PHOSPHATE INTO NON-NUCLEOTIDE PROTEIN-BOUND PHOSPHORUS FRACTIONS OF RESPIRING CAT BRAIN SLICES
Authors: Findlay Muriel , Strickland K. P. , Rossiter R. J.
Published: October 2017

Slices of cat brain respiring in a Krebs–Ringer bicarbonate medium were found to incorporate inorganic phosphate labelled with P32 into two non-nucleotide protein-bound phosphorus fractions, which are referred to as the residue organic phosphorus (ROP) and the "phosphoprotein" (PP), respectively. The addition of glucose or mannose to the medium increased the incorporation into both fractions. The addition of fructose, galactose, pyruvate, lactate, succinate, or L-glutamate failed to increase the incorporation into either fraction.Anaerobic conditions, homogenization of the tissue, or the addition of a wide range of metabolic inhibitors (cyanide, azide, iodoacetate, fluoride, nembutal, malononitrile, chloretone) inhibited the incorporation. The incorporation was also inhibited by 2,4-dinitrophenol in concentrations that do not inhibit oxygen consumption.These results are compared and contrasted with previous findings on the incorporation of P32 into the lipid phosphorus and pentosenucleic acid of brain slices.
DIRECT CURRENT POTENTIAL AND pH OF SEVERAL VARIETIES OF SKIN NEOPLASMS
Authors: Inch W. R.
Published: October 2017

A study of 36 subjects having skin neoplasms of three degrees of malignancy is described. The hydrogen ion concentration was determined using a Beckman model G pH meter with glass and calomel electrodes while d-c. potentials were measured using a d-c. vacuum tube amplifier and silver – silver chloride electrodes.The results indicate that there is no correlation between malignancy and absolute value of potential, but a correlation between malignancy and pH difference (pH neoplasm − pH normal) and between malignancy and the 'extra positivity' (absolute d-c. potential − 0.059 pH difference) does exist.
THE ACTIONS OF α-TOCOPHEROL ON MAMMALIAN HEARTS
Authors: Lu F. C. , Allmark M. G. , Graham W. D.
Published: October 2017

The effects of α-tocopherol were studied in a large number of experiments using isolated perfused mammalian hearts as well as the dog heart in situ. Under these conditions no significant pharmacodynamic actions of this agent, either on the coronary flow or the heart contraction, were demonstrable.
ASSAY OF THYROTROPHIN BY THE ACCUMULATION OF RADIOACTIVE IODINE IN THE THYROID OF THE INTACT RAT
Authors: Stephenson N. R. , McKinley W. P. , Kavanagii P. J.
Published: October 2017

The ability of the thyroid gland of intact weanling rats to collect injected radioactive iodine was diminished by inclusion of a small amount of iodinated casein in the diet. The administration of exogenous thyrotrophin increased the thyroidal uptake of I131 in rats treated in this manner. Both the degree of inhibition of the thyroid and the ability of the animals to differentiate between dosage levels of thyrotrophin were dependent upon the amount of iodinated casein in the diet. Graded doses of thyrotrophin provided a linear log dose –response line over the range 0.01 to 0.08 U.S.P. units. The response approached a maximum value at dose levels above 0.16 U.S.P. units. The thyroid gland of the female weanling rat retained, on the average, significantly more radioactive iodine than that of the male weanling rat when stimulated by thyrotrophin. Although the hormonal response was not correlated with the body weight of the rats within dosage groups, more precise assays were obtained by equalizing the total weight of the rats in each dosage group before the assay. Relatively large doses of I131 appeared to have an adverse effect on the precision of the assay but did not influence the response to thyrotrophin.
DEPOLYMERIZATION OF DEXTRAN BY HYDROGEN PEROXIDE
Authors: Levi Irving , Lozinski Ezra
Published: October 2017

It was observed that when very dilute solutions of hydrogen peroxide were employed for the purpose of destroying pyrogens in aqueous dextran solutions, a marked depolymerization of the polysaccharide molecule occurred. Further study demonstrated this effect to occur over a wide range of temperature, pressure, time, and concentration of hydrogen peroxide. It was therefore possible to use hydrogen peroxide in place of the usual hydrolytic agents, such as acids, for the depolymerization of native dextran to smaller molecular weight fragments suitable for use as a blood plasma extender.
STUDIES WITH ALDOSTERONE
Authors: Venning E. H. , Giroud C. J. P. , Dyrenfurth I. , Beck J. C.
Published: October 2017

In 10 experiments, 50–98% of aldosterone added to urine could be recovered in the neutral fraction. Purification of the urinary extracts by various chromatographic procedures resulted in loss of activity. Following an intravenous administration of 600 μgm. aldosterone to an adrenalectomized patient, 13.3% was recovered in the urine in the neutral fraction. The greater part of this material was in the form of a conjugate.
STUDIES ON THE GLYCOPROTEINS OF THE DOMESTIC FOWL: II. THE HEXOSAMINE CONTENT OF CERTAIN TISSUES OF THE SEXUALLY IMMATURE PULLET AND SOME EFFECTS THEREON OF GONADAL HORMONES
Authors: Anastassiadis P. A. , Maw W. A. , Common R. H.
Published: October 2017

The concentration of total hexosamine (as free base) in the dry matter of tissues of the pullet was high in cartilage (8.0 mgm. per gm.) and in oviduct (6.4 mgm. per gm.); medium in comb and wattles, tendon, and lungs (3.0 to 5.5 mgm. per gm.); and low in voluntary muscle (1.5 mgm. per gm.). Dry defatted skin contained 8.3 mgm. per gm. Total serum hexosamine was 52 mgm. per 100 ml. and was increased significantly to about 67 mgm. per 100 ml. by treatment with estradiol benzoate (ODB) and to about 72 mgm. per 100 ml. by ODB plus testosterone propionate (TST). Serum protein was also increased significantly by the hormonal treatments, but to a relatively greater extent. The magnum of the hypertrophied oviducts of pullets treated with ODB was relatively high in dry matter (22.0%), and this dry matter was relatively rich in hexosamine (13.8 mgm. per gm.) and low in hydroxyproline (2.9 mgm. per gm.). The dry matter of the uterus and vagina was relatively low in hexosamine (6.0 mgm. per gm.) and rich in hydroxyproline (5.7 and 10.5 mgm. per gm. for uterus and vagina respectively). Concurrent administration of ODB and TST led to a greater degree of hypertrophy of the oviducts than did administration of ODB alone; both the weight and total hexosamine content of the magnum showed a greater relative increase than did the values for vagina and uterus. Some modifications of the method of determining the hexosamine content of tissues are described.
A NOTE ON THE STOIGHIOMETRY OF ADSORPTION OF ANIONS BY LYSOZYME
Authors: Colvin J. Ross
Published: October 2017

Ten adsorbed anions of monovalent methyl orange, Orange II, or picric acid are necessary and sufficient to precipitate one lysozyme molecule at pH 5.5 in 0.05 M acetate buffer at 32°, whereas only five of divalent 2,4-dinitro-1-naphthol-7-sulphonic acid (flavianic acid) are required. These results are consistent with a hypothesis of interacting hydration effects.
OBSERVATIONS ON THE ACTION OF HEXAMETHONIUM BROMIDE IN TOURNIQUET SHOCK IN RATS
Authors: Spoerel W. E. G. A.
Published: October 2017

Rats subjected to tourniquet shock were treated with hexamethonium bromide (C6), a ganglionic blocking agent. The effect of this agent on survival, blood pressure, fluid loss, and hemoconcentration was studied. Hemoglobin as determined by the cyanhemoglobin method was used as an indicator of hemoconcentration. The fluid loss into the injured hindlegs was measured by the estimation of the fluid content of muscle tissue. The survival rate was significantly improved by administration of C6 at the time the tourniquets were released. Treatment with C6 two and four hours after tourniquet release provided little or no protection. No difference in fluid loss could be detected between treated and untreated rats, but the hemoconcentration was less in treated animals and followed a different pattern. Treated rats showed no blood pressure response to the release of the tourniquets. The protection provided by C6 is thought to be due mainly to its effect on the general circulation.
THE EFFECTS OF ADRENAL CORTICAL EXTRACTS UPON CARBOHYDRATE METABOLISM WHEN MEDIUM COMPOSITION IS ALTERED
Authors: Clarke D. W.
Published: October 2017

The effects of adrenal cortical extract upon glucose uptake and upon glycogen synthesis in the isolated rat diaphragm were studied in three different media. The maximum inhibition by the extract upon the measured effects was seen in a medium which contained both sodium and potassium ions. In media which contained either of these alone as the major cation, there was no significant inhibition.
CARDIAC AUTOMATISM AND CHOLINE ACETYLATION IN RATS ON THIAMINE- AND PANTOTHENIC- ACID-DEFICIENT DIETS
Authors: Beznák A. B. L. , Alphen G. W. H. M. van
Published: October 2017

The choline acetylating activity of extracts of the acetone powders of hearts of rats fed on diets deficient in thiamine, in pantothenate, and in thiamine plus pantothenate was found to be the same as it was in rats on a complete synthetic diet, although severe changes in the electrocardiogram (e.c.g.) were present in rats on the two thiamine-deficient diets. These e.c.g. changes were the same as the ones described in rats on diets deficient in other factors besides thiamine. The rats on the pantothenic-acid-deficient diet grew as normals did and no e.c.g. abnormalities were seen in them. The symptoms of thiamine deficiency were attenuated and their appearance delayed when pantothenate also was deleted from the diet.
THE EFFECT OF CHLORPROMAZINE GIVEN WITH REINFUSION ON THE MORTALITY RATE FROM STANDARDIZED HEMORRHAGIC SHOCK IN THE RAT
Authors: Carruthers G. F. , Gowdey C. W.
Published: October 2017

Anesthetized rats were subjected to a standardized hemorrhagic shock procedure; one group (20 animals) served as controls and another group (eight animals) was injected with chlorpromazine. The treated animals died very quickly: only one survived more than 12 hr. and none 48 hr.; the average survival time of 18 control fatalities was 14.0 hr., and two lived. Of the various cardiovascular and respiratory indices measured, only the post-reinfusion arterial pressure was different in the treated from that in the control group. Differences between the control groups in this and in an earlier series (Downie and Stevenson (1955)) can probably be accounted for by differences in the temperature of the laboratory.
A THEORETICAL TREATMENT OF GLUCOSE REABSORPTION IN THE KIDNEY
Authors: Burgen A. S. V.
Published: October 2017

The equations for solute reabsorption in the proximal kidney tubule are derived, assuming Michaelis–Menten type kinetics and linear water reabsorption. Application of the equations to glucose shows that the transport system has a high affinity for glucose, being half saturated at less than 5 mgm. 100 ml. Most of the departure from ideal behavior of the human glucose saturation curve cannot be attributed to an unsaturated transport system. A dispersal of tubule absorptive capacity in a log-normal distribution can account for the curvature of the saturation curve.
ADAPTIVE ENZYME FORMATION BY DIHYDROSTREPTOMYCIN- DEPENDENT ESCHERICHIA COLI
Authors: Polglase W. J. , Peretz Susan , Roote Susan M.
Published: October 2017

An apparent requirement for dihydrostreptomycin for the formation of adaptive enzymes has been demonstrated in a strain of E. coli which requires this antibiotic for cell multiplication. The effect of dihydrostreptomycin on the formation of adaptive enzymes by E. coli has been shown to be consistent with the effect of the antibiotic on bacterial multiplication.
THE EFFECT OF THE SARINASE LEVELS OF LIVER ON THE SURVIVAL OF RABBITS INJECTED WITH SARIN
Authors: Adie Peter A.
Published: October 2017

The effect in rabbits of the sarinase levels of liver and plasma, and of cholinesterase levels of plasma on survival after repeated intraperitoneal or subcutaneous doses of sarin has been investigated. When the intraperitoneal route was used a significant correlation was found between liver sarinase and survival. Survival after subcutaneous injection was not affected by the liver sarinase. No correlation was found between plasma sarinase or plasma cholinesterase and survival for either the intraperitoneally or subcutaneously injected rabbits.
EXPERIMENTS ON THE USE OF SILICIC ACID FOR STEROID CHROMATOGRAPHY
Authors: Linford J. H.
Published: October 2017

Mixtures of pure sterols, and extracts of hydrolyzed urine, were chromatographed on columns of silicic acid. The results were observed spectrometrically using a sulphuric acid – methanol color reagent. Dry silicic acid retained or altered the sterols. When the silicic acid contained free water the sterols were distributed between the surface of the solid and the developing solvent. The adherence to the solid phase decreased with increase of free water and with increased solubility of the sterol in the solvent. As the free water was increased liquid–liquid partition was observed. The adherence of the sterol to the silica surface increased with the number of hydroxyl groups in the sterol molecule. Silicic acid columns are therefore particularly suited to the separation of sterols that differ in their number of hydroxyl groups and to the detection of the production of artifacts by loss of the hydroxyl group.
ENZYMATIC PROPERTIES OF BOVINE PLASMIN PREPARATIONS; EVIDENCE FOR SIMILARITY TO BUT NON-IDENTITY WITH TRYPSIN
Authors: Ronwin Edward
Published: October 2017

The enzymatic properties of both choloroform-only activated and trypsin–chloroform activated bovine fibrinolysin (plasmin) have been studied and compared with trypsin. These studies accentuate the remarkable similarity between plasmin and trypsin but definitely establish their distinct individuality and the validity of the procedure using trypsin to activate plasminogen to plasmin.
EXTRACELLULAR ORGANIC NITROGEN IN USTILAGO MAYDIS FERMENTATION BROTHS
Authors: Dulaney Eugene L. , Bilinski E. , McConnell W. B.
Published: October 2017

Free amino acids and small peptides make up most of the extracellular organic nitrogen in media from shaken and aerated Ustilago maydis fermentations. Of the 3.5 mgm./ml. ammonia nitrogen added, 2.9 mgm./ml. remained in the extracellular broth. This extracellular nitrogen contained 1.17 mgm./ml. of organic nitrogen and 1.74 mgm./ml. of residual ammonia nitrogen. At least 53% of extracellular organic nitrogen is in the form of free amino acids. Fifteen amino acids were estimated quantitatively in acid-hydrolyzed broth and a particularly high level of arginine (1.14 mgm./ml.) was found. The amounts of methionine and tryptophan in the broth were quite low but the lysine concentration 0.400 mgm./ml. was relatively high.
STUDIES OF FATTY ACID OXIDATION: 4. THE EFFECTS OF FATTY ACIDS ON THE OXIDATION OF OTHER METABOLITES
Authors: Scholefield P. G.
Published: October 2017

Fatty acids inhibit the oxidation of pyruvate by rat-kidney mitochondria but the extent of inhibition depends upon the nature and amount of agent added to stimulate the oxidation. The longer chain fatty acids are more effective inhibitors and, in general, the even-numbered fatty acids show greater inhibitory effects than the adjacent odd-numbered fatty acids. Under conditions where 2, 4-dinitrophenol (DNOP) and the fatty acids separately have little effect on the respiratory activity of rat-kidney mitochondria with pyruvate as substrate, the addition of both fatty acid and DNOP results in an extensive inhibition. At low concentrations the fatty acids are oxidized by rat-kidney mitochondria but at concentrations of 10−3 M and higher they inhibit their own oxidation, the oxidation of pyruvate, and those of the acids of the tricarboxylic acid cycle. The oxidation of pyruvate by rat-brain mitochondria is insensitive to decanoate but both the fumarate- and DNOP-stimulated oxidations of pyruvate are sensitive to the presence of decanoate. In contrast, Nembutal inhibits both the oxidation of pyruvate alone and the fumarate-stimulated oxidation of pyruvate. Possible mechanisms for the observed inhibitory effects of fatty acids are discussed.
PUNGENIN: A GLUCOSIDE FOUND IN LEAVES OF PICEA PUNGENS (COLORADO SPRUCE)
Authors: Neish A. C.
Published: October 2017

A new crystalline glucoside named pungenin (m.p. 198–199 °C., [Formula: see text], water) was isolated from leaves or leafy twigs of Picea pungens Engelm. collected during the winter months. It comprised about 5% of the dry weight. Hydrolysis of this glucoside gave 3,4-dihydroxyacetophenone and D-glucose. Methylation of pungenin gave a crystalline pentamethyl ether (m.p. 97 °C.) which gave isoacetovanillone on hydrolysis, and was found to be identical with the methyl ether obtained by complete methylation of isoacetovanillone-β-D-glucopyranoside. Pungenin is thus 3-(β-D-glucopyranosyloxy)-4-hydroxyacetophenone, a monoglucoside of 3,4-dihydroxyacetophenone.
THE EFFECT OF INGESTED CHLORTETRACYCLINE ON SOME HYDROLASES AND ORGANS ASSOCIATED WITH THE DIGESTIVE PROCESS IN GROWING PIGS: I. ASSAY METHODS FOR PROTEASE, AMYLASE, AND CELLULASE ACTIVITY
Authors: Vonk M. A. A. , McElroy L. W. , Berg R. T.
Published: October 2017

Methods are described for the determination of protease, amylase, and cellulase activity of unknown solutions permitting accurate measurements over a wide range of enzyme concentration in a single determination. Regression equations were obtained relating: (a) protease concentrations to the optical densities of casein hydrolyzates precipitated with an acetic acid solution (correlation coefficient, r = −0.9806; D.F. 70), (b) optical densities of starch–iodine complexes formed in starch hydrolyzates to amylase concentrations (multiple correlation coefficient, R = 0.9918; D.F. 62), and (c) cellulase concentrations to relative viscosities of carboxymethyl cellulose hydrolyzates (correlation coefficient, r = −0.9554; D.F. 34). The influence of chlortetracycline on the activity of these hydrolases in vitro was investigated and no effect was detected at a level of 5 p.p.m.
PAPER ELECTROPHORETIC SEPARATION OF WATER-SOLUBLE CASTOR BEAN PROTEINS
Authors: Adie P. A. , Robinson A. D.
Published: October 2017

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