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991.
Integrating classical biological control with other management techniques such as herbicide, fire, mechanical control, grazing, or plant competition, can be the most effective way to manage invasive weeds in natural areas and rangelands. Biological control agents can be protected from potential negative impacts of these weed control methods through untreated refugia or by applying the treatment at a time when the agent is not vulnerable. A literature review of experiments that integrated biological control with other management strategies from 1987 to 2017 yielded 39 terrestrial and 16 aquatic studies. The tactics most frequently integrated with biological control were herbicide applications and plant competition. Despite numerous examples of successful programs and calls for more widespread integration of biological control with other weed management strategies, there was no increase in the number of studies reported annually over time. Additional studies investigating the ecological and economic benefits of integrated weed management are needed. 相似文献
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994.
Corinne Rocchini Roswitha M. Marx Joachim Schnorr von Carosfeld Harold E. Kasinsky Ellen Rosenberg Freya Sommer Juan Ausio 《Journal of molecular evolution》1996,42(2):240-246
We have analyzed the chromosomal protein composition of the sperm from several species belonging to three different classes (Hydrozoa, Scyphozoa, Anthozoa) of the phylum Cnidaria. In every instance, the sperm nuclear basic proteins (SNBPs) were found to consist of one to two major protein fractions that belong to the histone H1 family, as can be deduced from their amino acid composition and solubility in dilute perchloric acid, and the presence of a trypsin-resistant core. In those species where mature spawned sperm could be obtained, we were able to show that these proteins completely replace the somatic histones from the stem cells that are present at the onset of spermatogenesis. The presence of a highly specialized histone H1 molecule in the sperm of this phylum provides support for the idea that the protamine-like proteins (PL) from higher groups in the phylogenetic tree (and possibly protamines as well) may all have evolved from a primitive histone H1 ancestor. 相似文献
995.
Alison Galloway Mary Ellen Morbeck Adrienne L. Zihlman 《Primates; journal of primatology》1996,37(4):443-455
Male and female chimpanzees from Gombe National Park, Tanzania (Pan troglodytes schweinfurthii) differ in live body weights but not in cranial capacity or fore-and hindlimb long bone lengths. Skeletal dimensions of the
limbs and vertebral column indicate a mosaic of sex differences. Vertebral column measurements generally are greater in males.
While linear measurements identify differences in the breadth and depth of the lower cervical and upper thoracic vertebrae,
areal assessments show significant differences in weight-bearing surfaces throughout the thoracic and lumbar segments. These
can be interpreted in terms of distribution of weight and body composition (i.e. amount of musculature). 相似文献
996.
T. E. Gottschalk J. E. Nielsen P. Rasmussen 《Applied microbiology and biotechnology》1996,45(1-2):240-244
An endogenous β-glucuronidase that hydrolyses the chromogenic substrate 5-bromo-4-chloro-3-indolyl-β-D-glucuronide (X-gluc) in Aspergillus niger is reported. The activity was induced when the fungus was grown in media containing xylan, but was either very low, or absent,
when grown on glucose. Endogenous β-glucuronidase was primarily located in newly formed hyphae, and was apparent at pH values
between 3 and 6. Hydrolysis of X-gluc was sensitive to the inhibitor D-saccharic acid 1,4-lactone and was irreversibly inactivated by heating. The bacterial uidAβ-glucuronidase reporter gene was strongly expressed in the hyphae of transformed A. niger but, in contrast to the endogenous activity, the enzyme was also active at pH 7–8.5. Histochemical localization of uidA expression in A. niger, without interference from the endogenous β-glucuronidase activity, was achieved by staining at this pH.
Received : 22 March 1995/Received last revision : 17 August 1995/Accepted : 22 August 1995 相似文献
997.
Biochemical and molecular characterization of the oxidative branch of glycerol utilization by Citrobacter freundii. 总被引:5,自引:4,他引:1 下载免费PDF全文
Glycerol dehydrogenase (EC 1.1.1.6) and dihydroxyacetone kinase (EC 2.7.1.29) were purified from Citrobacter freundii. The dehydrogenase is a hexamer of a polypeptide of 43,000 Da. The enzyme exhibited a rather broad substrate specificity, but glycerol was the preferred substrate in the physiological direction. The apparent Kms of the enzyme for glycerol and NAD+ were 1.27 mM and 57 microM, respectively. The kinase is a dimer of a polypeptide of 57,000 Da. The enzyme was highly specific for the substrates dihydroxyacetone and ATP; the apparent Kms were 30 and 70 microM, respectively. The DNA region which contained the genes encoding glycerol dehydrogenase (dhaD) and dihydroxyacetone kinase (dhaK) was cloned and sequenced. Both genes were identified by N-terminal sequence comparison. The deduced dhaD gene product (365 amino acids) exhibited high degrees of homology to glycerol dehydrogenases from other organisms and less homology to type III alcohol dehydrogenases, whereas the dhaK gene product (552 amino acids) revealed no significant homology to any other protein in the databases. A large gene (dhaR) of 1,929 bp was found downstream from dhaD. The deduced gene product (641 amino acids) showed significant similarities to members of the sigma 54 bacterial enhancer-binding protein family. 相似文献
998.
Christian Schobert Pia Großmann Maren Gottschalk Ewald Komor Attila Pecsvaradi Uta zur Mieden 《Planta》1995,196(2):205-210
The cut hypocotyl of Ricinus communis L. seedlings exudes phloem sap which contains a characteristic set of proteins (Sakuth et al. 1993, Planta 191, 207–213). These sieve-tube exudate proteins were probed with antibodies to highly conserved proteins, namely ribulose 1,5-bisphosphate carboxylase-oxygenase (Rubisco), Rubisco subunit-binding protein, heat-shock protein (HSP 70), chaperonin GroEL and ubiquitin. Homologous proteins in the sieve-tube exudate were identified with antisera to HSP 70, Rubisco-subunit-binding protein and ubiquitin. Ribulose-1,5-bisphosphate carboxylase-oxygenase, which was present in the tissue, was not detected. Of all the cross-reactive proteins detected, ubiquitin was special because the ubiquitin-to-protein ratio in the sieve-tube exudate was higher than in both the surrounding hypocotyl and in the cotyledonary tissues. Therefore, ubiquitin features properties which favour its transfer into the sieve tubes and which might rely on efficient transport through plasmodesmata. It is assumed that chaperones and ubiquitin are needed for the maintenance of sieve-tube function, e.g. to ensure correct folding of proteins. Their possible involvement in protein translocation through plasmodesmata from companion cells to sieve tubes is discussed.Abbreviations HSP
heat-shock protein
- Rubisco
ribulose1,5-bisphosphate carboxylase-oxygenase
- RBP
Rubisco-subunit-binding protein
- STEP
sieve-tube exudate protein
This research was supported by a TEMPUS grant European Community, Brüssel to E.K., which enabled the stay of A.P. The authors thank Dr. A. Bachmair (Institut für Botanik, Universität Wien, Austria), Prof. D. Wolf and Dr. A. Finger (Institut für Biochemie, Universität Stuttgart, Germany), Dr. S. Jentsch (Friedrich-Miescher Laboratorium, Max-Planck Institut Tübingen, Germany), Prof. U. Kull (Biologisches Institut, Universität Stuttgart, Germany), and Dr. T. Gatenby (Dupont, Wilmington, Del., USA) for generous supply of antisera used in this study. Improvement of English style was due to D. Schobert-Wiese. 相似文献
999.
1000.
Ellen M. Lake Hua Jiang Frederick R. Blattner Julius Adler 《Cellular and molecular neurobiology》1995,15(2):283-288
Summary 1. This research was carried out to compareEscherichia coli bacteria with animals in their response tol-aspartate andl-glutamate and their analogues.2. Various analogues of aspartate and glutamate known to be neurotransmitters at synapses were shown to be attractants forE. coli.3. The amino acid sequences of the animal receptors and the bacterial receptor, however, have no detectable relationship. Based on the amino acid sequence, evolutionarily the two systems appear not to be related. 相似文献