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1.
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
2.
The strain Penicillium purpurogenum P-26 was subjected to UV irradiation and N-methyl-N′-nitro-N-nitrosoguanidine treatment and mutants were isolated capable of synthesizing cellulase under the conditions of a high concentration
of glucose. Initially mutants resistant to catabolite repression by 2-deoxy-D-glucose were isolated on Walseth’s cellulose/agar plates containing 15–45 mM 2-deoxy-D-glucose. These mutants were again screened for resistance to catabolite repression by glycerol or glucose on Walseth’s cellulose/agar
plates containing 50 g/l glycerol or 50 g/l glucose respectively. Four mutants with different sizes of clearing zone on Walseth’s
cellulose/agar plates containing 50 g/l glucose were selected for flask culture. Among them, the mutant NTUV-45-4 showed better
carboxymethylcellulase activity in flask culture containing 1% Avicel plus 3% glucose than did the parental strain.
Received: 9 October 1995/Received revision: 27 November 1995/Accepted: 8 January 1996 相似文献
3.
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
4.
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
5.
M. Hayat 《BioControl》1970,15(4):387-399
An account of the Indian forms belonging to the familySigniphoridae is given. The family is represented by two genera namely,Thysanus
Walker andChartocerus
Motschulsky. The genusThysanus with the speciesT. ater
Walker is reported for the first time from India, and is redescribed in greater detail. The subdivision of the genusChartocerus into three subgenera (Chartocerus s. str.,Xana
Kurdjumov, andSigniphorina
Nikol’skaja.) proposed byRosanov (1965) is accepted. In the subgenusXana two new species are described and two already known species are recorded. In the subgenusSigniphorina one new species is described. A new generic character in the subgenital plate of the genusThysanus is proposed. The generic character in the subgenital plate of the genusChartocerus described byMan Mohan (1963) is confirmed.
Résumé La famille desSigniphoridae est représentée par deux genres:Thysanus Walker etChartocerus Motschulsky. Le genreThysanus avec l’espèceT. ater Walker est indiquée pour la première fois de l’Inde et est redécrite avec plus de détails. La subdivision du genreChartocerus en trois sous-genres (Chartocerus s. str.,Xana Kurdjumov etSigniphorina Nikol’skaja proposée parRosanov (1965) est acceptée. Dans le sous-genreXana deux nouvelles espèces (C. (X.) hyalipennis sp. n. etC. (X.) walkeri sp. n.) sont décrites et deux espèces déjà connues sont répertoriée. Parmi celles-ciC. (X.) kurdjumovi (Nikol’skaja) est mentionnée pour la première fois en Inde. Les males de l’espèceC. (X.) kerrichi sont décrits. Dans le sous-genreSigniphorina une nouvelle espèce est décrite.相似文献
6.
Nicole Hawlitzky 《BioControl》1979,24(3):237-245
Résumé Quand des œufs d’ages variés (1 h à 5 j) du lépidoptèreAnagasta kuehniella
Zell. sont offerts aux femelles parasites dePhanerotoma flavitestacea
Fisch., l’endroit où l’œuf du parasite est déposé, dépend du stade de développement de l’œuf h?te au moment de l’oviposition.
Lorsque l’œuf h?te est agé de 1 h à 3 j, la ponte a lieu dans le vitellus. Par contre, si l’œuf du parasite est déposé dans
un œuf agé de 4 jours ou plus, il est directement pondu dans l’embryon h?te.
Selon ces résultats, il semble que la pénétration de l’œuf du parasite ou de la larve est due uniquement à un mouvement passif
causé par la migration du vitellus dans le tube digestif moyen de l’embryon h?te.
Ces différents points et l’effet de la piq?re de l’ovipositeur sur l’embryon h?te, la nature de l’élimination des larves surnuméraires
sont discutés.
Summary When lepidopterous eggs of varied ages (1 hour to 5 days) are offered to parasitic females ofPhanerotoma flavitestacea Fisch., the location where the parasitic egg is deposited, depends on the developmental stage of the host egg at the time of oviposition. When the host egg is 1 hour to 3 days old, the laying takes place in the yolk. On the other hand, if the parasite egg is deposited in a four day old or an older host egg, it is directly laid in the host embryo. According to these results, it seems that the penetration of the parasitic egg or larva is only a passive movement caused by the migration of the yolk into the midgut of the host embryo. These different points and the effect of the sting of the ovipositor on the host embryo, the nature of the elimination of the supernumerary larva, are discussed.相似文献
7.
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
8.
l-DOPA is an amino acid derivative and most potent drug used against Parkinson’s disease, generally obtained from Mucuna pruriens seeds. In present communication, we have studied the in vitro production of l-DOPA from l-tyrosine by novel bacterium Bacillus sp. JPJ. This bacterium produced 99.4% of l-DOPA from l-tyrosine in buffer (pH 8) containing 1 mg ml−1 cell mass incubated at 40°C for 60 min. The combination of CuSO4 and l-ascorbic acid showed the inducing effect at concentrations of 0.06 and 0.04 mg ml−1, respectively. The activated charcoal 2 mg ml−1 was essential for maximum bioconversion of l-tyrosine to l-DOPA and the crude tyrosinase activity was 2.7 U mg−1 of tyrosinase. Kinetic studies showed significant values of Y
p/s (0.994), Q
s (0.500) and q
s (0.994) after optimization of the process. The production of l-DOPA was confirmed by analytical techniques such as HPTLC, HPLC and GC–MS. This is the first report on rapid and efficient
production of l-DOPA from l-tyrosine by bacterial source which is more effective than the plant, fungal and yeast systems. 相似文献
9.
Résumé Après l’éclosion de la larve du parasitePhanerotoma flavitestacea
Fisch., la membrane embryonnaire persiste pendant 3,5 jours. Différents r?les de cette membrane sont envisagés et discutés. Trois
d’entre eux sont retenus (alimentation et protection de la larve parasite et action sur le développement ultérieur de l’h?te).
Ce choix est basé sur nos propres observations biologiques et physiologiques et celles de divers auteurs concernant d’autres
insectes entomophages.
Summary After the hatching of the parasitic larva,Phanerotoma flavitestacea Fisch., the embryonic membrane persists around it during three days and a half. The different hypothetical roles of this membrane are discussed. Three are retained, on the base of our biological and physiological observations interesting this larva or different authors’ observations concerning other entomophagous insects. These roles are alimentary and protective functions for the parasite and action on the host physiology.相似文献
10.
Horinouchi N Ogawa J Kawano T Sakai T Saito K Matsumoto S Sasaki M Mikami Y Shimizu S 《Biotechnology letters》2006,28(12):877-881
A one-pot enzymatic synthesis of 2′-deoxyribonucleoside from glucose, acetaldehyde, and a nucleobase was established. Glycolysis by baker’s yeast (Saccharomyces cerevisiae) generated ATP which was used to produce d-glyceraldehyde 3-phosphate production from glucose via fructose 1,6-diphosphate. The d-glyceraldehyde 3-phosphate produced was transformed to 2′-deoxyribonucleoside via 2-deoxyribose 5-phosphate and then 2-deoxyribose 1-phosphate in the presence of acetaldehyde and a nucleobase by deoxyriboaldolase, phosphopentomutase expressed in Escherichia coli, and a commercial nucleoside phosphorylase. About 33 mM 2′-deoxyinosine was produced from 600 mM glucose, 333 mM acetaldehyde and 100 mM adenine in 24 h. 2′-Deoxyinosine was produced from adenine due to the adenosine deaminase activity of E. coli transformants. 相似文献
11.
The biometals iron (Fe), manganese (Mn) and copper (Cu) have been associated to Parkinson’s disease (PD) and Parkinsonism.
In this work, we report for the first time that acute (15 mM for up to 5 days) or chronic (0.5 mM for up to 15 days) Fe, Mn
and Cu exposure significantly reduced life span and locomotor activity (i.e. climbing capabilities) in Drosophila melanogaster. It is shown that the concentration of those biometals dramatically increase in Drosophila’s brain acutely or chronically fed with metal. We demonstrate that the metal accumulation in the fly’s head is associated
with the neurodegeneration of several dopaminergic neuronal clusters. Interestingly, it is found that the PPL2ab DAergic neuronal
cluster was erode by the three metals in acute and chronic metal exposure and the PPL3 DAergic cluster was also erode by the
three metals but in acute metal exposure only. Furthermore, we found that the chelator desferoxamine, ethylenediaminetetraacetic
acid, and d-penicillamine were able to protect but not rescue D. melanogaster against metal intoxication. Taken together these data suggest that iron, manganese and copper are capable to destroy DAergic
neurons in the fly’s brain, thereby impairing their movement capabilities. This work provides for the first time metal-induced
Parkinson-like symptoms in D. melanogaster. Understanding therefore the effects of biometals in the Drosophila model may provide insights into the toxic effect of metal ions and more effective therapeutic approaches to Parkinsonism. 相似文献
12.
Kornelia Ellwanger Andre Eich Michael Nickel 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》2007,193(1):1-11
Sponges (Porifera) are nerve- and muscleless. Nevertheless, they react to external stimuli in a coordinated way, by body contraction,
oscule closure or stopping pumping activity. The underlying mechanisms are still unknown, but evidence has been found for
chemical messenger-based systems. We used the sponge Tethya wilhelma to test the effect of γ-aminobutyric acid (GABA) and glutamate (l-Glu) on its contraction behaviour. Minimal activating concentrations were found to be 0.5 μM (GABA) and 50 μM (l-Glu), respectively. Taking maximum relative contraction speed and minimal relative projected body area as a measure of the
sponge’s response, a comparison of the dose–response curves indicated a higher sensitivity of the contractile tissue for GABA
than for l-Glu. The concentrations eliciting the same contractile response differ by about 100-fold more than the entire concentration
range tested. In addition, desensitising effects and spasm-like reactions were observed. Presumably, a GABA/l-Glu metabotropic receptor-based system is involved in the regulation of contraction in T. wilhelma. We discuss a coordination system for sponges based on hypothetical chemical messenger pathways.
Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorized users.
K. Ellwanger and A. Eich contributed equally and designed and performed experiments, analysed data and revised the paper,
M. Nickel designed the study and experiments, analysed data, prepared the figures, wrote and revised the paper. 相似文献
13.
Walter W. Ferguson 《Primates; journal of primatology》1989,30(3):383-387
A partial mandible with two molars intact was recovered between 1981 and 1984 from deposits of the Middle Pliocene at Tabarin,
in Kenya. It has been described and assigned toAustralopithecus cf.afarensis
Johanson, White, andCoppens, 1978, with the condition that if ‘A. afarensis’ is revised, then the attribution may change. The taxon ‘A. afarensis’ was found to be invalid and was revised. The smaller specimens of ‘A. afarensis,’ to which the Tabarin mandible was said to be similar, were redescribed asHomo antiquus
Ferguson, 1984. Since the Tabarin mandible andH. antiquus are successive transients of the same gens and are allopatric, the Tabarin hominid population is described as an earlier
chronosubspecies,Homo antiquus praegens ssp. n. 相似文献
14.
Studies on the <Emphasis Type="Italic">Pycnoporus sanguineus</Emphasis> CCT-4518 laccase purified by hydrophobic interaction chromatography 总被引:1,自引:0,他引:1
A laccase from Pycnoporus sanguineus was purified by two steps using phenyl-Sepharose columm. A typical procedure provided 54.1-fold purification, with a yield
of 8.37%, using syringaldazine as substrate. The molecular weight of the purified laccase was 69 and 68 kDa as estimated by
12% (w/v) SDS-PAGE gel and by gel filtration, respectively. The K
m values for the substrates ABTS, syringaldazine, and guaiacol were 58, 8.3, and 370 μM, respectively. The enzyme’s pH optimum
for syringaldazine was 4.2 and optimal activity was 50°C. The enzyme showed to be thermostable because when kept at 50°C for
24 and 48 h it retained 93 and 76% activity. This laccase was inhibited by l-cysteine, β-mercaptoethanol, NaN3, NaF, and HgCl2. 相似文献
15.
Charl��ne Bouchaud Margareta Tengberg Patricia Dal Pr�� 《Vegetation History and Archaeobotany》2011,20(5):405-417
The discovery of seeds and textiles from Gossypium (cotton) in Achaemenian levels of the mid-6th–late 4th century b.c. at Qal’at al-Bahrain, Bahrain and in early 1st millennium a.d. at Mada’in Salih, Saudi Arabia, reveals the role played by the Arabian Peninsula as a textile production centre during the
centuries before and after the beginning of the Christian era. Both these sites were situated on important trade routes, overseas
(Qal’at al-Bahrain) and overland (Mada’in Salih), and it is likely that at least part of the cotton production was intended
for trade, complementing and perhaps competing with other sources of cotton textiles in the contemporary Middle East. In the
arid climate of the Arabian Peninsula, cotton was probably grown in association with irrigated date palm gardens where a wide
array of other crops was grown, as is shown by the analysis of charred seeds and wood from occupation levels at both sites.
The present article places these particular finds in the larger context of cotton cultivation in the Middle East and India. 相似文献
16.
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
17.
S. G. Atienza M. J. Giménez A. Martín L. M. Martín 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2000,101(5-6):970-976
Eighty-eight lines of the species Hordeum chilense Roem. et Schult., representative of the variability found in the latter’s distribution zone, were analysed. Monomeric prolamins
(protein fraction corresponding to wheat gliadins) were studied using the SDS-PAGE technique. The analysis of the different
bands was performed using the programme BioImage
™
Whole Band Analyzer. Jaccard’s coefficient of similarity was calculated, and the lines were grouped by cluster analysis using UPGMA. A great
variability was found between the different lines studied. Forty-two different bands were identified, all of which were polymorphic.
Sixty-eight different patterns of monomeric prolamins were identified within the 82 lines studied. A dendrogram was obtained
from the analysis of the groups. No relationship between the distribution of the variability in the dendrogram and the geographical
origin or the ecological characteristics of the species could be detected. It is concluded that H. chilense is an important pool of variability for storage proteins that could be used in cereal breeding.
Received: 10 January 2000 / Accepted: 21 March 2000 相似文献
18.
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
19.
The present study reports a simple rapid method for isolating the zinc-containing metalloprotease camelysin from Bacillus thuringiensis subsp. israelensis (Bti) by extraction from intact bacterial cells with egg l-α-phosphatidylcholine containing monolamellar liposomes, followed by separation on a sucrose gradient. Characterization of
the isolated camelysin revealed a molecular weight of 23 kDa and a pI of 6.2. The camelysin exhibited maximal activity against the substrate azocasein at a temperature of 37°C and pH 7.5. However,
the enzyme’s activity remained high also at basic pH values (8–10). In a rich growth medium (LB), camelysin appeared at the
late logarithmic phase of Bti growth and reached its maximum in the stationary phase. Camelysin was shown to activate the protoxins Cyt1Aa and Cyt2Ba produced
by Bti. The hemolytic activity of Cyt1Aa increased from 40 to 70% and that of Cyt2Ba from 6 to 50% in the presence of 50% (w/w)
camelysin. It is concluded that these protoxins can be activated not only by insect gut proteases, but also by the endogeneous
metalloprotease camelysin of the Bti bacterium. 相似文献
20.
This work studied the effect of two cell-surface lectins isolated from the nitrogen-fixing soil bacterium Azospirillum brasilense Sp7 and from its mutant defective in hemagglutinating activity, A. brasilense Sp7.2.3, on the activities of α-glucosidase, β-glucosidase and β-galactosidase in the exocomponent, membrane and apoplast
fractions of wheat-seedling roots. Lectin (40 μg mL−1) incubation for 1 h of the plant fractions increased the enzymes’ activities; both wild-type and mutant lectins were most
stimulatory to the activities of all the exocomponent-fraction enzymes studied and to the apoplast-fraction β-glucosidase.
Pretreatment of the lectins with their carbohydrate hapten, L-fucose, lowered the effect. The observed differences in the lectins’ ability to influence enzyme catalytic activity are explained
by change in the antigenic properties of the mutant lectin. 相似文献