bluuebunny/crossref_metadata_2025_split huggingface dataset:
Function and Redundancy of the Chaplin Cell Surface Proteins in Aerial Hypha Formation, Rodlet Assembly, and Viability in
Streptomyces coelicolor
Authors: Di Berardo Christina , Capstick David S. , Bibb Maureen J. , Findlay Kim C. , Buttner Mark J. , Elliot Marie A. 
Published: June 2008

ABSTRACT

The chaplins are a family of eight secreted proteins that are critical for raising aerial hyphae in
Streptomyces coelicolor
. These eight chaplins can be separated into two main groups: the long chaplins (ChpA to -C) and the short chaplins (ChpD to -H). The short chaplins can be further subdivided on the basis of their abilities to form intramolecular disulfide bonds: ChpD, -F, -G, and -H contain two Cys residues, while ChpE has none. A “minimal chaplin strain” containing only
chpC
,
chpE
, and
chpH
was constructed and was found to raise a substantial aerial mycelium. This strain was used to examine the roles of specific chaplins. Within this strain, the Cys-containing ChpH was identified as the major polymerization unit contributing to aerial hypha formation and assembly of an intricate rodlet ultrastructure on the aerial surfaces, and the two Cys residues were determined to be critical for its function. ChpC augmented aerial hypha formation and rodlet assembly, likely by anchoring the short chaplins to the cell surface, while ChpE was essential for the viability of wild-type
S. coelicolor
. Interestingly, the lethal effects of a
chpE
null mutation could be suppressed by the loss of the other chaplins, the inactivation of the twin arginine translocation (Tat) secretion pathway, or the loss of the rodlins.
Synthetic Lethality with the
dut
Defect in
Escherichia coli
Reveals Layers of DNA Damage of Increasing Complexity Due to Uracil Incorporation
Authors: Ting Helen , Kouzminova Elena A. , Kuzminov Andrei 
Published: June 2008

ABSTRACT

Synthetic lethality is inviability of a double-mutant combination of two fully viable single mutants, commonly interpreted as redundancy at an essential metabolic step. The
dut-1
defect in
Escherichia coli
inactivates dUTPase, causing increased uracil incorporation in DNA and known synthetic lethalities [SL(
dut
) mutations]. According to the redundancy logic, most of these SL(
dut
) mutations should affect nucleotide metabolism. After a systematic search for SL(
dut
) mutants, we did identify a single defect in the DNA precursor metabolism, inactivating thymidine kinase (
tdk
), that confirmed the redundancy explanation of synthetic lethality. However, we found that the bulk of mutations interacting genetically with
dut
are in DNA repair, revealing layers of damage of increasing complexity that uracil-DNA incorporation sends through the chromosomal metabolism. Thus, we isolated mutants in functions involved in (i) uracil-DNA excision (
ung
,
polA
, and
xthA
); (ii) double-strand DNA break repair (
recA
,
recBC
, and
ruvABC
); and (iii) chromosomal-dimer resolution (
xerC
,
xerD
, and
ftsK
). These mutants in various DNA repair transactions cannot be redundant with dUTPase and instead reveal “defect-damage-repair” cycles linking unrelated metabolic pathways. In addition, two SL(
dut
) inserts (
phoU
and
degP
) identify functions that could act to support the weakened activity of the Dut-1 mutant enzyme, suggesting the “compensation” explanation for this synthetic lethality. We conclude that genetic interactions with
dut
can be explained by redundancy, by defect-damage-repair cycles, or as compensation.
Engineering of Functional Replication Protein A Homologs Based on Insights into the Evolution of Oligonucleotide/ Oligosaccharide-Binding Folds
Authors: Lin Yuyen , Lin Li-Jung , Sriratana Palita , Coleman Kelli , Ha Taekjip , Spies Maria , Cann Isaac K. O. 
Published: June 2008

ABSTRACT

The bacterial single-stranded DNA-binding protein (SSB) and the archaeal/eukaryotic functional homolog, replication protein A (RPA), are essential for most aspects of DNA metabolism. Structural analyses of the architecture of SSB and RPA suggest that they are composed of different combinations of a module called the oligonucleotide/oligosaccharide-binding (OB) fold. Members of the domains
Bacteria
and
Eukarya
, in general, contain one type of SSB or RPA. In contrast, organisms in the archaeal domain have different RPAs made up of different organizations of OB folds. Interestingly, the euryarchaeon
Methanosarcina acetivorans
harbors multiple functional RPAs named MacRPA1 (for
M. acetivorans
RPA 1), MacRPA2, and MacRPA3. Comparison of MacRPA1 with related proteins in the publicly available databases suggested that intramolecular homologous recombination might play an important role in generating some of the diversity of OB folds in archaeal cells. On the basis of this information, from a four-OB-fold-containing RPA, we engineered chimeric modules to create three-OB-fold-containing RPAs to mimic a novel form of RPA found in
Methanococcoides burtonii
and
Methanosaeta thermophila
. We further created two RPAs that mimicked the RPAs in
Methanocaldococcus jannaschii
and
Methanothermobacter thermautotrophicus
through fusions of modules from MacRPA1 and
M. thermautotrophicus
RPA. Functional studies of these engineered proteins suggested that fusion and shuffling of OB folds can lead to well-folded polypeptides with most of the known properties of SSB and RPAs. On the basis of these results, different models that attempt to explain how intramolecular and intermolecular homologous recombination can generate novel forms of SSB or RPAs are proposed.
Primary aldosteronism and aldosterone-associated hypertension
Authors: Rayner B 
Published: June 2008

The field of primary aldosteronism (PA) and aldosterone-related hypertension has undergone rapid evolution. From a relatively rare curiosity PA has become a common problem particularly in selected hypertensive populations. Patients with PA and aldosterone-related hypertension appear to be at higher cardiovascular and renal risk than comparable patients with essential hypertension probably due to the pleiotropic effects of aldosterone. Aldosterone is also linked to metabolic syndrome and diabetes.The aldosterone-to-renin ratio (ARR) has allowed the widespread screening for PA, but the exact cut-off values may vary in different population groups. All patients with hypertension and hypokalaemia, and young patients with hypertension, hypertension with an incidental adrenal mass, and severe or resistant hypertension should be screened. The use of the ARR to screen all hypertensives for PA is controversial as the test lacks specificity and many patients with false-positive tests will undergo complex and expensive testing to confirm the diagnosis. The fludrocortisone suppression test, the saline infusion test or 24-hour aldosterone excretion may be used to confirm PA in patients with a positive ARR. Adrenal venous sampling is the most reliable test to detect the presence of an aldosterone-producing adenoma, but spiral CT scan or adrenocortical scintigraphy may be useful in centres without facilities for adrenal venous sampling.Spironolactone is emerging as an important antihypertensive agent in patients with resistant hypertension and aldosterone-related hypertension. The ARR may be a useful guide to drug selection in hypertensives patients, but further research is needed to make more definitive recommendations.
Prices in Mecca During the Mamluk Period
Authors: Mortel Richard T. 
Published: June 2008

AbstractThe political, social and economic history of western Arabia during the medieval period still remains terra incognita for the great majority of Islamicists, in spite of the intrinsic importance of the subject and the existence of a corpus of first-rate source materials. The goal of this article is to contribute to a deeper understanding of the economic history of Mecca through a detailed study of the available information regarding the prices of cereal grains and other foodstuffs there during the Mamluk period. So that the maximum advantage may be derived from the discussion, it will be preceeded by a short outline of the political history of Mecca during Mamluk times, as well as the salient features of its economy.
The Islamic Background To Indian History
Authors: Athar Ali M. 
Published: June 2008

AbstractThe medieval period of Indian history, as conventionally fixed by historians, c. 1000 to c. 1750 had so deep an imprint of Islam, that during much of the period, India could be held to belong culturally to the Islamic World, not on its periphery, but close to its core. It is, of course, the uniqueness of India's situation, that at the very same time, strictly in terms of its Hindu component, it could be said to be a world in its own right, with Islam only as a peripheral phenomenon. Yet, since the Islamic connexion greatly influenced the political structure, the fiscal system and even much of the network of internal commerce and external trade, it is crucial to understand the background that Islam provided to Indian history, or in other words, to understand Islamic history till the arrival of Islam in Northern India, c. 12001). A splendid effort to do so was provided by Professor Mohammad Habib in his introduction to a reprint of Vol. II of Elliot and Dowson's History of India as told by its Own Historians, Aligarh, 1952. A year later Hamilton Gibb came out with his well known essay, "An Interpretation of Islamic History", published in Journal of World
Origine, sens et survie du terme boécien «secundum placitum»
Authors: Engels J. 
Published: June 2008

AbstractLa première fois que SECUNDUM PLACITUM se présente chez Boèce, c'est dans sa traduction de la définition aristotélienne du nom du Peri Herméneias (I6 a I9): "Ovoμα μν oüv στ φων σημαντιΧ Χατ συνΧην...Ι qu'il rend: NOMEN ERGO EST VOX SIGNIFICATIVA SECUNDUM PLACITUM. L'expression y est le substitut de Χατ συνν qu'on interprète en général comme signifiant «par convention». En interprétant SECUNDUM PLACITUM de la même manière, on a l'avantage de faire correspondre parfaitement l'expression latine au sens usuel du terme grec. En a-t-on le droit? Ici surgissent deux problèmes connexes: Quel est le sens exact de Χατ συνΧην, quel est celui de SECUNDUM PLACITUM? Commençons par le premier.
Some new Evidence on twelfth century Logic
Authors: De Rijk L.M. 
Published: June 2008

AbstractIT is well known that the art of logic (logica or diale(c)tica) knew a remarkable flourishing period during the twelfth century. In the first half of the century its main centres in Paris were: the School of Notre DameI, of St. Victor2, of the Petit Pont3 and of Mont Ste Geneviève4. The present paper aims to offer some new evidence from the manuscripts on the teaching of logic as given in the School of Mont Ste
Prophecy and Ecstasy in Greco-Roman Religion and in 1 Corinthians
Authors: Callan Terrance 
Published: June 2008

AbstractWe have seen that in Greek prophètes means spokesman in a very general sense. Most characteristically it designates the medium, or mantis, at an oracle, who is considered a spokesman for the god of the oracle. This mantic prophecy is accompanied by trance, i.e., when the mantis functions as spokesman, his or her ordinary consciousness is replaced by another. However, in an effort to explain why oracles at Delphi are no longer given in verse, Plutarch develops a theory according to which even prophecy in this sense does not involve trance, but makes use of the ordinary consciousness of the mantis. In addition to this use of prophetes, it is also used to designate other spokesmen. Some of these are considered entranced, e.g., poets, the spokesmen of the Muses, in Plato's view. But most are not, e.g., poets according to the understanding of poetic inspiration reflected in Pindar, and those who functioned at oracles as spokesmen for the mantis. I have argued that the uses of prophètes in Greek correspond fairly well to the apparent range of meanings for nabi in the OT. But the use of prophètes to translate nabi involved a shift of emphasis: while in Greek prophètes mainly designates those who prophesy in trance, as a translation for nabi, prophètes mainly designates those whose prophecy is apparently not accompanied by trance. This can be seen clearly in Philo who knows of prophecy as a trance phenomenon, but who sees at least Moses mainly as a prophet whose prophecy does not involve trance. This understanding of prophecy results both from fidelity to scripture and from Philo's desire to praise Moses and account for certain difficulties in scripture.
The Behaviour of the Male Three-Spined Stickleback in a Natural Situation: a Quantitative Description
Authors: Wootton R.J. 
Published: June 2008

AbstractThe behaviour of male Three-spined Sticklebacks in a stretch of the River Wear in Durham City is described. Quantitative data on parental behaviour and the effects of creeping through agreed closely with data collected under laboratory conditions. A decrease in territory size during the parental phase was noted. Nest raiding and egg stealing were also observed. Circling and dorsal-pricking were important components of courtship behaviour.
The Role of the Epaulets in the Red-Winged Blackbird, (Agelaius Phoeniceus) Social System
Authors: Smith Douglas G. 
Published: June 2008

AbstractThe role of the epaulets of the male Red-winged blackbird, Agelaius phoeniceus, was examined. Territorial male Red-wings were captured and their epaulets blackened with Nyanzol D, a permanent black dye. The following results were obtained: 1) Sixty-four percent of the males with black epaulets lost their territories while only eight percent of the control males lost theirs. 2) Males with epaulets blackened prior to pair formation were still able to "attract" females and mate successfully. It was concluded that the epaulets communicate threat between rival males but that they have little if any role in intersexual encounters. The epaulets, therefore, have probably evolved in response to intrasexual (epigamic) selection pressure.
Sexual Behavior in Continuously Cycling Rats
Authors: Fitzroy Hardy Donna 
Published: June 2008

AbstractThe succession of vaginal and behavioral changes was followed throughout the estrous cycle of ten continuously cycling female rats. Interruption of cycles by pregnancy or pseudopregnancy was prevented by the use of the vaginal mask. The behavioral indices were Lordosis Quotient, a measure of sexual responsiveness, and Rejection Quotient, a measure of tolerance by the female of mounting by the male. Before the onset of lordosis, which took place during proestrus, females rejected males on many attempted mounts, although rejection decreased rapidly with rise in frequency of lordosis. Full receptivity was displayed for 6 to 9 hours, but females began to reject the males while still displaying high levels of lordosis. The total period of 19 hours over which lordosis is shown was divided into pre-heat, heat, and post-heat periods.
Socio-Ecological Implications of Individual Differences in Wolf Litters : a Developmental and Evolutionary Perspective
Authors: Fox M.W. 
Published: June 2008

AbstractIndividual differences in response to a number of animate and inanimate moving and non-moving stimuli were studied in 18 wolf cubs from four litters. Social rank was closely correlated with reactivity, exploratory behavior and prey-killing ability. A wide range of variability in test scores was found in all litters. It is proposed that pack integration and coordination of activities is enhanced by intra-specific socialization, social facilitation, and leader-follower relationships between subordinates and the more exploratory alpha individual. The evolutionary advantages of selection for individual differences or behavioral polymorphism within litters are discussed and inferences drawn for significance in pack formation. This hypothesis is supported by contrasting evidence of greater behavioral homogeneity in less social canids, where intra-specific aggression and mutual proximity intolerance prevents pack formation and leads to dispersal of the litter.
The Role of the Nasonov Gland Pheromone in Crop Communication By Honeybees (Apis Mellifera L.)
Authors: Free J.B. , Williams Ingrid H. 
Published: June 2008

Abstract
Honeybees were trained to forage at a dish of sucrose syrup. Those that danced on their return home showed a greater tendency to expose their Nasonov glands on later trips than those that did not dance, but, contrary to previous supposition, these two activities were not closely correlated; each may, therefore, be released by a different stimulus or, perhaps, by different intensities of the same stimulus.
The Effect of a Supra-Normal Threat Stimulus On the Growth Rates and Dominance Relationships of Pairs of Male and Female Golden Hamsters
Authors: Payne A.P. , Swanson H.H. 
Published: June 2008

Abstract
Weanling male and female golden hamsters were caged in matched-weight pairs on removal from their mothers. There were pairs of littermates and non-littermates of each sex. One partner of each pair was dyed on the chest with a black commercial hair-dye. Over 20 days, dyed animals of both sexes had a significantly higher growth rate than their untreated partners. In observations carried out between days 10-20 of the test period, dyed animals were found to be aggressively dominant over their untreated partners, and showed more aggressive behaviour. It is suggested that the growth of untreated animals was inhibited as a "stress" response either to the presence of the supra-normal threat stimulus, or to the aggressive relationship which resulted from it.
The Relation Between Eliciting Stimulus Strength and Habituation of the Threat Display in Male Siamese Fighting Fish, Betta Splendens
Authors: Figler Michael H. 
Published: June 2008

AbstractThe threat display of the male Siamese fighting fish (Betta spiendens) is a highly integrated phenomenon, involving approach, extension of the gill covers (opcrculae) and brachiostegal membranes, erection of the medial fins, intense deepening of body color, orientation movcmcnts, and undulatory movements. Many qualitatively different stimuli are capable of eliciting the complete threat display (e.g., live male Betta, mirror image, two dimensional cut-out). However, the relations between the initial eliciting strength of the threat stimulus and the degree of habituation, retention, and recovery of habituation have not been systematically investigated. These relations are important in an eliciting stimulus and competing response theory of habituation like that of RATNER (1970). To investigate the above relations, 40 adult male Bettas were randomly assigned to four independent groups (n = 10). Each S in a particular group was exposed to one of four different eliciting stimuli for two 40 minute sessions separated by a 24 hour rest period. The four thrcat elicitors were: a live unhabituated, highly responsive male Bettca (Unhab. male); a mirror image (Mirror) ; a livc habituatcd, relatively unrcsponsive male Betta (Hab. male) ; and a two dimensional cut-out of a male Betta in lateral display (Cut-out). During threc ro minute observation periods in each session, five different reliable components of the display were simultaneously recorded: air gulping frequency (AG), gill cover erection frequency (GF), gill cover erection duration (GD), fin erection frequency (FF), and fin erection duration (FD). For all five dependent measures, the Unhab. male stimulus was the strongest elicitor followed by the Mirror, Hab. male and Cut-out stimuli, respectively. Only two of the dependent measures (GD, FD) showed a systematic decrement for all stimulus groups. With respect to both of these measures, initial eliciting stimulus strength (response level during the first 10 minute observation) was positively related to absolute response decrement, and proportion of recovery of habituation. Initial eliciting stimulus strength was inversely related to the proportion of decrement across sessions, and the proporton of retention of habituation over a 24 hour period. Four of the threat components (GF, GD, FF, FD) were highly positively related. AG was shown not to be an integral component of the display, itself. The data provided support for portions of an eliciting stimulus and competing response theory of habituation.
Effects of Conspecifics and Vegetation On Nest Site Selection in Gasterosteus Aculeatus L
Authors: Jenni Donald A. 
Published: June 2008

AbstractVegetation and conspecific rivals both exert significant influences on the locations of territories as determined by the nest sites selected by naive male three-spined sticklebacks. The effect of a row of vegetation along one end of a tank depends on the size of the tank. In small tanks (up to I20 cm), a row of vegetation at one end repels males. In the 300 cm tank, a row of vegetation at one end did not appear to influence the overall distribution of nests, but those nesting in the end with the vegetation tended to nest in the vegetation. A row of vegetation at one end of the 600 cm ditch attracted some males who nested in the row. The remaining nests were located in the middle portion of the ditch,, and the end effect in the unplanted ditch disappeared. Thus the effect of a row of vegetation depends on the amount of open space available in front of it. In the 600 cm ditch, a row of vegetation standing away from the end attracted 65 per cent of the males who selected nest sites within and adjacent to the rows compared to 40 per cent when the row was at the end. The difference is not quite significant. With a rival behind a glass plate 30 cm from one end of the otherwise bare 600 cm tank, rival males selected nest sites at the opposite end of the tank. The repelling effect of a rival was effective over a relatively large distance in this bare environment. The repelling effect of the rival was exaggerated in some experiments in which a second glass plate was placed 30 cm from the opposite end. Separate experiments proved that a glass plate attracted males who tended to nest near it. The repelling effects of a rival was greatly reduced when a row of vegetation was placed at some distance from his territory boundary (glass plate).
The Effects of Ambient Temperature and Population Density On Aggression in Two Inbred Strains of Mice, Mus Musculus
Authors: Greenberg Gary 
Published: June 2008

AbstractI. 240 Male mice from the aggressive C57BL/I05 strain and non-aggressive A/J strain were subjected to temperatures of I8.3°C, 2I.I°C, 26.7°C, 32.2°C or 35°C for 24 hours. 2. The mice were then crowded in groups of 8 into enclosures with floor areas of 0.09, 0.2I, or 0.38 m2. 3. The frequency of aggression acts (biting frequency) was recorded for each animal 30, 60, and 90 min. after being put in the enclosures. 4. Aggression was lowest at I8.3°C and 35°C and tended to increase as the temperature increased from I8.3°C to 32.2°C. 5. There appeared to be more aggression in the more crowded conditions than in the less crowded conditions. 6. The results were attributed to metabolic changes induced by increasing temperature and to perceptual and proximity effects resulting from increasing population density.