共查询到20条相似文献,搜索用时 15 毫秒
1.
Maltotriose is metabolized by baker’s and brewer’s yeast only oxidatively, with a respiratory quotient of 1.0, the
being, depending on the strain used, 0–11, as compared with
of 6–42μL CO2 per h per mg dry substance. The transport appeared to proceed by facilitated diffusion (no effects of NaF, iodoacetamide
and 3-chlorophenylhydrazonomalononitrile) with a KT of more than 50mm and was inhibited by maltose > maltotriose > methyl-α-D-glucoside > maltotetraose >D-fruetose >D-glucose. The transport was present constitutively in bothSaccharomyces cerevisiae (baker’s yeast) and inS. uvarum (brewer’s yeast) and it was not significantly stimulated by preincubation with glucose or maltose. The pH optimum was 4.5–5.5,
the temperature dependence yielded an activation energy of 26 kJ/mol. 相似文献
2.
K. A. Aliferis S. Jabaji 《Metabolomics : Official journal of the Metabolomic Society》2010,6(1):96-108
Rhizoctonia solani AG-3 is a soilborne plant pathogen that forms resting vegetative structures called sclerotia. These compact structures are
crucial to the pathogen’s survival and pathogenesis. The metabolic changes occurring during sclerotia development were monitored
using proton nuclear magnetic resonance (1H NMR) spectroscopy and gas chromatography–mass spectrometry (GC-MS). The validation, discrimination, and the establishment
of correlative relationships between metabolite signals were performed by principal component analysis (PCA) and partial least
squares-discriminant analysis (PLS-DA). The results of the analyses suggested that out of the 116 compounds that were simultaneously
analyzed and compared using GC-MS, α-α-trehalose, d-glucose, 9-(Z)-octadecenoic and 9,12-octadecadienoic acids, xylitol, and glucitol were key metabolites that were highly dependent on the
developmental stage of the sclerotia contributing to their discrimination and classification. Furthermore, the application
of 1H NMR and GC-MS metabolic fingerprinting on the same biological sample provided complementary information illustrating the
value of this integrated approach in the study of metabolic changes in fungal structures. 相似文献
3.
M. J. A. Simpson 《International journal of primatology》1988,9(3):257-274
Ten-to 17-week-old rhesus monkey infants that received hits from companions other than their mother at high rates (relative
to their rates of involvement in playful social encounters with those companions) tended to be members of mother-infant dyads
that were vigilant. Criteria of vigilance were frequent contacts between mother and infant during the first 5 sec of the infants’
social encounters and/or a bias of mother-infant contacts toward that time. Infants that received few hits per encounter came
from both vigilant and nonvigilant dyads. When analyzed alone, mothers’ rates showed the same trends. High levels of vigilance
tended to reduce infants’rates of making social contacts. Maternal social rank and other measures of the infants’ social involvement
were not correlated with vigilance. There is no evidence that mothers and infants were in conflict with each other about interrupting
the infants’ encounters. Understanding vigilance becomes important whenever vigilant activity conflicts with other activities.
Special problems arise because decisions about vigilance levels require judgments of risk based on the kinds of events that
occur only rarely if vigilance is effective. A model providing a framework for studies of vigilance against the risks of infants’
social activities was developed. It recognizes that (1) risk-reducing vigilant behavior can conflict with acquiring information
about risk; (2) in social situations where reliable estimates of risk are impossible, individuals might follow rules of thumb (e.g., be
restrictive) rather than modify behavior moment by moment according to the current situation;and (3) at the dyad’s optimum balance between vigilance for the current infant and investment in subsequent off-spring, the
infant will not be totally protected, so that while dyads at higher risks are more vigilant, the risks are also realized to
a greater extent (e.g., itin terms of the number of hits received per encounter). 相似文献
4.
A. C. D’Andrea 《Economic botany》2008,62(4):547-566
T’ef (
Eragrostis tef
) in Ancient Agricultural Systems of Highland Ethiopia. T’ef (Eragrostis tef) has been cultivated in the Horn of Africa for at least 2,000 years. The earliest known agricultural systems in this region
date to the Pre-Aksumite period (800–400 b.c.) and appear to have focused on Near Eastern crops, with indigenous African species increasing in importance during Aksumite
times (400 b.c.–a.d. 700). While palaeoethnobotanical data are available from Pre-Aksumite and late Aksumite periods, macroscopic botanical remains
from the site of Ona Nagast, northern Ethiopia, provide a first glimpse of agricultural systems dating to Proto-Aksumite (400–50
b.c.), Early to Classic (50 b.c.–a.d. 340), and Post-Aksumite (a.d. 700–900) times. Archaeological t’ef remains from Ona Nagast are examined in detail. Guidelines are developed for the identification
of t’ef grains preserved on archaeological sites, with a focus on how to differentiate them from seeds of wild Eragrostis species. Charring experiments reveal that in some cases t’ef may not survive high temperatures tolerated by larger cereal
grains, such as wheat and barley. The domestication history of t’ef appears to be different from some other cereals, a factor
which may explain the preponderance of indeterminate Eragrostis seeds in archaeological samples. Selection of large seed size and intensified tillage were not key factors in t’ef domestication.
Early cultivators were likely selecting for increased branching and higher percentage seed set under conditions of minimal
tillage. 相似文献
5.
Magdalena Janus 《International journal of primatology》1989,10(3):243-261
Play, grooming, and proximity, and the degree to which these were reciprocated between pairs, were studied in immature sibling
and nonsibling rhesus monkeys (Macaca mulatta)in four established captive groups over two seasons. “Interaction reciprocity” and “partner reciprocity” were assessed for
each dyad for each of the three behaviors. In play, interaction reciprocity was based on the ratio between the play initiations
by each dyad member,in grooming on the ratio between the grooming durations by each dyad member, and in proximity on the relative responsibility
for proximity maintenance. Two or three most frequent (top) partners for each behavior were found for each individual. If
two monkeys were among each other’s top partners, they were said to be reciprocal partners. Monkeys played with nonsiblings
as much as with siblings but spent more time grooming and in proximity with siblings than with nonsiblings. Same-age nonsiblings
(peers) were more frequent partners than other nonsiblings for each behavior. Siblings’ grooming interactions were more reciprocal
than those of nonsiblings. There was no such effect for play and proximity. All-male dyads tended to be more reciprocal in
play interactions, and all-female dyads tended to be more reciprocal in grooming interactions. In play, but not in grooming
or proximity, the interaction reciprocity of reciprocal partners was higher than that of nonreciprocal dyads. It is argued
that the three behaviors have similar roles in infant’s social development but they differ in the expression of this role.
Hence the reciprocity patterns vary with the behavior. 相似文献
6.
Marques MP Gil FP Calheiros R Battaglia V Brunati AM Agostinelli E Toninello A 《Amino acids》2008,34(4):555-564
The present study aims at determining the structure-activity relationships (SAR’s) ruling the biological function of MGBG
(methylglyoxal bis(guanylhydrazone)), a competitive inhibitor of S-adenosyl-l-methionine decarboxylase displaying anticancer activity, involved in the biosynthesis of the naturally occurring polyamines
spermidine and spermine. In order to properly understand its biochemical activity, MGBG’s structural preferences at physiological
conditions were ascertained, by quantum mechanical (DFT) calculations. 相似文献
7.
A 2 × 2 factorial arrangement of treatments in randomized design was conducted to investigate the effect of different selenomethionine
(SM) sources and levels on the productive performance of breeder hens and the Se distribution in the inclusion of eggs and
serum and tissues of breeder hens and its offspring. A total of 480 Ling-Nan-Huang breeder hens, 48 weeks of age, were allocated
to four treatments, each of which included three replicates of 40 hens. Pretreatment period was 2 weeks, and the experiment
lasted 8 weeks. Two SM forms of dl-SM and l-SM were supplemented at 0.15 or 0.30 mg Se/kg into the basal diet. Results showed that the Se level of 0.15 mg/kg supplemented
in the diet, compared to 0.30 mg/kg, significantly elevated the percentage of egg production (p < 0.05), hatchability (p < 0.01), and birthrate (p < 0.01), whereas the Se level of 0.30 mg/kg led to a higher Se content in egg contents, serum, and all tissues (p < 0.01). In addition, the form of dl-SM showed a significant increase in Se content of egg inclusion (p < 0.01), serum (p < 0.01), and all tissues (p < 0.01, except breeder hens’ pancreas and its offspring’s liver and breast muscle). The birthrate and yolk Se content were
markedly influenced by the interaction between Se source and Se level (p < 0.01). The above results suggested that dl-SM, compared to l-SM, had a similar equal effect on the performance of breeder hens, but dl-SM was superior to l-SM with respect to selenium distribution in egg inclusion, serum, and tissues. 相似文献
8.
Summary
Staphylococcus aureus can be enumerated in foods by the use ofChapman’s special medium (3), under application of the drop plate technique, recommended byMiles andMisra (6).
Colonies ofS.aureus so obtained can easily be macroscopically differentiated from aerobic sporeformers which grow also on this medium. The colonies
can be used immediately for testing their coagulase reaction. 相似文献
9.
Jean Ritter 《Plant Ecology》1972,25(1-4):357-365
Conclusions L’important mémoire deJ. Braun-Blanquet (1971) sur les Associations des basmarais suisses ainsi que d’autres travaux (E. Oberdorfer, 1970;H. Ellenberg, 1963), permettent d’affirmer que les groupements de l’Eriophorion latifoliae (Br.-Bl. et Tx. 43) et des Caricetalia Davallianae
(Br.-Bl. 49) sont représentés dans l’ensemble de la cha?ne alpine sur substrat riche en calcium et, en général, à partir de
l’étage montagnard supérieur.
Dans les Alpes et Préalpes fran?aises, plusieurs auteurs ont décrit des groupements du Caricion Davallianae (M. Guinochet
en Tinée et en Haute-Savoie, 1938 et 1939;G. Aubert, L. Borel, A. Lavagne etP. Moutte dans l’étage subalpin de la feuille d’Embrun-Est, 1965).
Dans le Vercors, seuleCh. Faure (1968) signale simplement l’existence du Caricion Davallianae (Klika 34) dans la partie septentrionale du massif (feuille
de Vif).
Enfin, dans les Préalpes du sud où les étages montagnard et, a fortiori, subalpin sont peu ou pas représentés.A. Archiloque, L. Borel etA. Lavagne (1970) constatent l’absence du Cratoneurion commutati (W. Koch. 28) et du Caricion Davallianae (Klika 34) sur la feuille
de Javie (préalpes de Digne).
Bien que la nature de la roche-mère soit déterminante pour l’existence des groupements de source et bas-marais alcalins, c’est
en définitive la relative permanence de l’alimentation en eau courante et fra?che qui représente le facteur décisif pour ces
associations. Dans la région étudiée, celles-ci sont à leur limite méridionale, ce qui confirme—s'il en était besoin—l’originalité
et la richesse de ce secteur des Préalpes.
Laboratoire de Taxonomie Expérimentale et de Phytosociologie de la Faculté des Sciences de BESAN?ON (25)—FRANCE. 相似文献
10.
Résumé Des adultes d’Ooencyrtus kuvanae (Howard) sortis d’œufs deLymantria dispar (L.) récoltés au Maroc et aux états-Unis ont été élevés séparément mais simultanément dans les mêmes conditions abiotiques.
On a évalué chez ces adultes des caractéristiques bionomiques telles que la longévité, la proportion de ♀ fécondes, la fécondité
réelle moyenne, la durée de la période de ponte et le pourcentage d’œufs viables développés par parthénogenèse. Chez la progéniture,
on a évalué la survie des larves et la proportion de ♀.
Aucune différence significative entre les 2 souches n’est apparue. Des croisements entre les 2 souches ont donné une descendance
comportant des proportions équivalentes de ♀.O. kuvanae avait été introduit au Maroc en 1926 depuis les états-Unis. Ainsi, 50 années d’acclimatation de ce parasite au Maroc (soit
près de 500 générations) n’ont pas modifié ses potentialités et n’ont pas suffi à induire chez lui une nouvelle race géographique.
Summary Adults ofOoencyrtus kuvanae (Howard) were recovered from eggs ofLymantria dispar (L.) collected in Morocco and in the U.S.A. They were reared separately and simultaneously under identical laboratory conditions. Various biological characteristics of adults from both sources were compared including longevity, proportion of fertilized versus unfertilized females, fecundity, duration of the oviposition period, and the percentage of viable eggs produced by virgin females. Also the survival of the larvae and the sex ratio of the 2 cultures were evaluated. Crossbreeding individuals of the 2 cultures resulted in a similar proportion of females in the progeny. In general there were no significan differences found between the 2 cultures.O. kuvanae had been introduced in Morocco in 1926 from the U.S.A. The adaptation of this parasite to conditions in Morocco during the ensuring 50 years since its establishment (about 500 generations) did not appear to modify the biotic potential of this species nor was it sufficient to induce the development of a new geographic race.相似文献
11.
Walter W. Ferguson 《Primates; journal of primatology》1989,30(4):561-569
Leonard andHegmon (1987) compare a series of dental metrics of ‘Australopithecus afarensis
Johanson, White, andCoppens, 1978’ with criteria for modern apes, to test the hypothesis that ‘A. afarensis’ represents a single species. They also compare the morphology of the lower third premolar. The dental breadth of ‘A. afarensis’ shows a wide range of variation, particularly in the lower third premolar morphology which displays greater variation than
in modern apes—yet the study concludes that the single species hypothesis cannot be rejected.
The study is flawed by applying criteria for pongids inappropriate for a hominid. When ‘A. afarensis’ is compared with criteria for hominids, the range of variation in dental size, breadth, and third premolar morphology is
greater than that in any hominid species. The single species hypothesis is, therefore, once again rejected. Moreover, the
name ‘A. afarensis’ is preoccupied byPraeanthropus africanus (Weinert) and must be dropped. 相似文献
12.
The aim of this study was to determine the levels of tissue and blood zinc (Zn), copper (Cu), magnesium (Mg) in nitric oxide
(NO) synthase blockade-induced hypertension. A group of albino rats received a NO synthase inhibitor, N
G
-nitro-l-arginine-methyl ester (l-NAME, 60 mg/kg/d) in their drinking water for 21 d. l-NAME intake caused a progressive rise in this group’s resting mean arterial blood pressure compared to a control group (p<0.01). There were no differences between the groups with regard to tissue and blood levels of Zn or Cu; however, Mg concentrations
were significantly lower in the hypertensive rats’ erythrocytes (20.2% reduction from control levels), cerebral cortex (17.0%),
heart (9.1%), renal cortex (12%), renal medulla (16.7%), and in the tissues of the caval vein (23.7%), mesenteric artery (29.8%),
renal artery (18.4%), and renal vein (22.1%). There were no significant Mg concentration changes in the hypertensive group’s
plasma, cerebellum, liver, duodenum, or aortal tissue. These findings suggest that Mg depletion may play a role in the blood
pressure rise that occurs in the model of chronic NO synthase inhibition-induced hypertension. 相似文献
13.
Pedro Américo D. Dias Ariadna Rangel-Negrin Joaquim J. Veà Domingo Canales-Espinosa 《Primates; journal of primatology》2010,51(1):91-94
Coalitions influence the establishment and maintenance of social relationships among males in primate species. In this study,
we compare the social behavior of males between two groups of Alouatta palliata: a group that was recently taken over by a coalition of two males (Mt), and a group that had a stable composition for at
least 9 months (Rh). We predicted that coalition partners would be more cooperative and less competitive than dyads formed
by immigrant and long-term resident males, and dyads formed by long-term resident males. Additionally, we predicted that these
dyadic trends should be reflected in more competition and less cooperation in the group that was taken over. As predicted,
the coalition partners of Mt showed the highest levels of cooperation among all dyads and the second lowest rate of agonism.
Cooperation was higher in the group that had a stable composition. Results from this study suggest that the social relationships
of male mantled howlers vary as a function of familiarity between males and that in the context of coalitionary takeovers,
coalitionary males are highly cooperative. Cooperation is lower in groups recently taken over and competition is more intense,
perhaps as a consequence of the process of establishment and reorganization of power relationships within some dyads. In the
future, we must determine the frequency of coalitionary takeovers in this population and assess its ultimate consequences
for male–male social relationships. 相似文献
14.
Kristian Kaufmann Nicole Shen Laura Mizoue Jens Meiler 《Journal of molecular modeling》2011,17(2):315-324
The PDZ domain is an interaction motif that recognizes and binds the C-terminal peptides of target proteins. PDZ domains are
ubiquitous in nature and help assemble multiprotein complexes that control cellular organization and signaling cascades. We
present an optimized energy function to predict the binding free energy (ΔΔG) of PDZ domain/peptide interactions computationally.
Geometry-optimized models of PDZ domain/peptide interfaces were built using Rosetta, and protein and peptide side chain and backbone degrees of freedom are minimized simultaneously. Using leave-one-out cross-validation,
Rosetta’s energy function is adjusted to reproduce experimentally determined ΔΔG values with a correlation coefficient of 0.66 and
a standard deviation of 0.79 kcal mol−1. The energy function places an increased weight on hydrogen bonding interactions when compared to a previously developed
method to analyze protein/protein interactions. Binding free enthalpies (ΔΔH) and entropies (ΔS) are predicted with reduced
accuracies of R = 0.60 and R = 0.17, respectively. The computational method improves prediction of PDZ domain specificity from sequence and allows design
of novel PDZ domain/peptide interactions. 相似文献
15.
Neisseria meningitidis, a gram negative bacterium, is the leading cause of bacterial meningitis and severe sepsis. Neisseria meningitidis genome contains 2,160 predicted coding regions including 1,000 hypothetical genes. Re-annotation of N. meningitidis hypothetical proteins identified nine putative peptidases. Among them, the NMB1620 protein was annotated as LD-carboxypeptidase
involved in peptidoglycan recycling. Structural bioinformatics studies of NMB1620 protein using homology modeling and ligand
docking were carried out. Structural comparison of substrate binding site of LD-carboxypeptidase was performed based on binding
of tetrapeptide substrate ‘l-alanyl-d-glutamyl-meso-diaminopimelyl-d-alanine’. Inspection of different subsite-forming residues showed changeability in the S1 subsite across different bacterial
species. This variability was predicted to provide a structural basis to S1-subsite for accommodating different amino acid
residues at P1 position of the tetrapeptide substrate ‘l-alanyl-d-glutamyl-meso-diaminopimelyl-d-alanine’. 相似文献
16.
In mitochondria, oxidative phosphorylation and enzymatic oxidation of biogenic amines by monoamine oxidase produce reactive
oxygen and nitrogen species, which are proposed to cause neuronal cell death in neurodegenerative disorders, including Parkinson’s
and Alzheimer’s disease. In these disorders, mitochondrial dysfunction, increased oxidative stress, and accumulation of oxidation-modified
proteins are involved in cell death in definite neurons. The interactions among these factors were studied by use of a peroxynitrite-generating
agent, N-morpholino sydnonimine (SIN-1) and an inhibitor of complex I, rotenone, in human dopaminergic SH-SY5Y cells. In control cells,
peroxynitrite nitrated proteins, especially the subunits of mitochondrial complex I, as 3-nitrotyrosine, suggesting that neurons
are exposed to constant oxidative stress even under physiological conditions. SIN-1 and an inhibitor of proteasome, carbobenzoxy-l-isoleucyl-γ-t-butyl-l-analyl-l-leucinal (PSI), increased markedly the levels of nitrated proteins with concomitant induction of apoptosis in the cells.
Rotenone induced mitochondrial dysfunction and accumulation and aggregation of proteins modified with acrolein, an aldehyde
product of lipid peroxidation in the cells. At the same time, the activity of the 20S β-subunit of proteasome was reduced
significantly, which degrades oxidative-modified protein. The mechanism was proved to be the result of the modification of
the 20S β-subunit with acrolein and to the binding of other acrolein-modified proteins to the 20S β-subunit.
Increased oxidative stress caused by SIN-1 treatment induced a decline in the mitochondrial membrane potential, ΔΨm, and activated
mitochondrial apoptotic signaling and induced cell death in SH-SY5Y cells. As another pathway, p38 mitogen-activated protein
(MAP) kinase and exracellular signal-regulated kinase (ERK) mediated apoptosis induced by SIN-1. On the other hand, a series
of neuroprotective propargylamine derivatives, including rasagiline [N-propargyl-1(R)aminoindan]and (−)deprenyl, intervened in the activation of apoptotic cascade by reactive oxygen species-reactive nitrogen
species in mitochondria through stabilization of the membrane potential, ΔΨm. In addition, rasagiline induced antiapoptotic
Bcl-2 and glial cell line-derived neurotrophic factor (GDNF) in SH-SY5Y cells, which was mediated by the ERK-nuclear factor
(NF)-κB pathway. These results are discussed in relation to the interaction of oxidative stress and mitochondria in the regulation
of neuronal death and survival in neurodegenerative diseases. 相似文献
17.
Kosei Izawa Koshin Kimura Alejandro Samper Nieto 《Primates; journal of primatology》1979,20(4):503-512
Ateles generally lives in small temporary subgroups. The authors studied the grouping of the monkey for two months and obtained
data concerning the subgroup size, composition, and inter-individual relationships. In general, the data agreed with that
obtained byKlein (1972). However, they discovered that large subgroups of the monkey were observed only in relation to the utilization of
a special place, the “salado” site. The authors discuss the reason for this. Criticism is given ofKlein's suggestions that the unique grouping ofAteles is a form of social adaptation to its palm-fruit eating behavior and that peripheral males exist in its social structure. 相似文献
18.
Lynn A. Fairbanks 《International journal of primatology》1988,9(5):425-441
Social relationships of 30 infants with their maternal grandmothers were studied in a captive colony of vervet monkeys (Cercopithecus aethiops sabaeus).Grandmothers and grandinfants formed affiliative relationships with one another that could be distinguished from the infant’s
relationships with nonkin adult females and with other adult female kin. The intensity of the grandmother—grandinfant relationship
varied according to several factors which were related to the infant’s vulnerability to mortality and to the grandmother’s
ability to provide effective social support. High-ranking grandmothers spent more time near their grandinfants, and initiated
more grooming and caretaking of their grandinfants, than did lower-ranking grandmothers. Grandmothers spent more time near
their daughter’s first surviving infant than near later-born infants, and when grandmothers had more than one adult daughter,
they spent more time near the infant of the younger daughter. These results, combined with the fact that the presence of a
maternal grandmother has been associated with a reduction in the rate of infant mortality in this colony (Fairbanks and McGuire,
1986), suggest that grandmothers are actively contributing to the reproductive success of their adult daughters and to the
survival of their infant grandoffspring. 相似文献
19.
Summary In roots which had been kept for ten days at 5–6°C the observed frequency of metaphase and anaphase reductional groupings
(R. G’s) was lower, that of prophase R. G’s higher, than in simultaneously fixed roots kept at 21–22°C. The frequency of R.
G’s can undergo considerable changes independent of temperature.
It appears highly likely that a process of somatic reduction may start from R. G’s but its successful conclusion would be,
at least in onion, a very rare event. In the present material the probability of a mitosis becoming a R. G. that finally leads
to a haploid cell with a complete genome is almost certainly less than 10−5 and more likely less than 10−6.
Contribution from the Programme in Cytology, Department of Botany, University of Wisconsin, Madison, supported by grants to
late Dr.C. Leonard Huskins from the American Cancer Society upon recommendation of the Committee on Growth of the National Research Council, from the
Rockefeller Foundation and from the Research Committee of the Graduate School with funds supplied by the Wisconsin Alumni
Research Foundation. 相似文献
20.
Gilligan’s (1982) refinement of Kohlberg’s theory on moral development operates on two theses: (1) females, more so than males,
reach moral decisions based on the personalities of the relevant individuals; and (2) female behaviors stemming from moral
decisions are based upon “care” and “responsibility for others.” This article accepts the first thesis but argues that the
second is incorrect. That is, self-interest—i.e., aiding “blood” kin and/or carefully monitoring reciprocity—rather than “altruism”
is argued to be the operant dynamic in forging distaff morality and resultant behavior. Six empirical examples are presented
as contraindicative of Gilligan’s second thesis. Finally, it is suggested that selection for the psychological traits of independence
and the mastery of subtle social chess yielded ancestral females who had more descendants—us—than did females with alternative
profiles.
Nancy S. Coney is a professor at Western Illinois University and is interested in both clinical and nonclinical aspects of
women’s psychology.
Wade C. Mackey is interested in biocultural anthropology and has authored two books on fathering:Fathering Behaviors (Plenum, 1995) andThe American Father (Plenum, 1996). 相似文献