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1.
Two varieties of grain sorghum were harvested at 10 intervals from 35–189 days post planting. Leaf, stem and head portions were separated before being prepared for chemical analysis or ensiled for 30 days in 1-1 silos with or without preservatives. The taller variety (FS-1b) accumulated 60% more dry matter than ORO-T with advancing plant maturity, while whole plant crude protein content decreased from near 20 to less than 7% for both varieties. Dry matter ensiling loss (DMEL) was different (P < 0.05) for each plant portion, but was lower and less variable after the 77-day harvest. Immature leaves and heads resulted in the greatest average DMEL of 31 and 24%, respectively. Propionic acid decreased DMEL, while an ammonia solution was ineffective when compared to control leaf, stem and heads. The DMEL of leaves was influenced (P < 0.05) by a varietal × modulus of fineness interaction while the stem exhibited an interaction with plant maturity × modulus of fineness. Modulus of fineness was not associated with levels of organic acid production in silages, but plant maturity significantly influenced acetic, propionic and butyric acid production in heads. These data indicated that numerous combinations of silage preservation techniques affected DMEL of sorghum plant portions at different maturities. 相似文献
2.
Virginia Edgcomb William Orsi John Bunge Sunok Jeon Richard Christen Chesley Leslin Mark Holder Gordon T Taylor Paula Suarez Ramon Varela Slava Epstein 《The ISME journal》2011,5(8):1344-1356
Microbial diversity and distribution are topics of intensive research. In two companion papers in this issue, we describe the results of the Cariaco Microbial Observatory (Caribbean Sea, Venezuela). The Basin contains the largest body of marine anoxic water, and presents an opportunity to study protistan communities across biogeochemical gradients. In the first paper, we survey 18S ribosomal RNA (rRNA) gene sequence diversity using both Sanger- and pyrosequencing-based approaches, employing multiple PCR primers, and state-of-the-art statistical analyses to estimate microbial richness missed by the survey. Sampling the Basin at three stations, in two seasons, and at four depths with distinct biogeochemical regimes, we obtained the largest, and arguably the least biased collection of over 6000 nearly full-length protistan rRNA gene sequences from a given oceanographic regime to date, and over 80 000 pyrosequencing tags. These represent all major and many minor protistan taxa, at frequencies globally similar between the two sequence collections. This large data set provided, via the recently developed parametric modeling, the first statistically sound prediction of the total size of protistan richness in a large and varied environment, such as the Cariaco Basin: over 36 000 species, defined as almost full-length 18S rRNA gene sequence clusters sharing over 99% sequence homology. This richness is a small fraction of the grand total of known protists (over 100 000–500 000 species), suggesting a degree of protistan endemism. 相似文献
3.
L M Garcia-Segura R Martinez-Rodriguez I Suarez B Fernandez-Ruiz 《Acta anatomica》1979,103(2):231-237
Myelin-associated carbohydrates were studied by means of histochemical techniques in the central nervous system of birds and mammals. Polianions in the surface of myelin and in interfascicular oligodendroglia were detected using histochemical techniques. Glycoproteins were studied by means of concanavalin A. The Con-A-PO-DAB sequence was used. Concanavalin-A-binding sites were detected in oligodendroglia and on the myelin surface. Similar results were observed in both birds and mammals. The processes of the interfascicular oligodendroglia also contain carbohydrates. A close association between the carbohydrates of these glial processes and the myelin surface carbohydrates was demonstrated, and their probable identity is assumed. 相似文献
4.
Lorences, E. P., Suárez, L. and Zarra, I. 1987. Hypocotyl growth of Pinus pinaster seedlings. Changes in the molecular weight distribution of hemicellulosic polysaccharides.
The changes in the molecular weight distribution of water-soluble hemicelluloses and xyloglucan during hypocotyl growth of intact seedlings of Pinus pinaster Aiton were investigated. The mass-average molecular weight of total polysaccharides of the hemicellulose fraction soluble in 4% KOH dramatically increased during hypocotyl growth while xyloglucan slightly decreased. These phenomena were due to an increase in the degree of polymerization of an arabinogalactan and a slight depolymer-ization in the xyloglucan present in this fraction. In the hemicellulose fraction soluble in 24% KOH, xyloglucan increased its degree of polymerization from day 7 to 10 after which it decreased slightly. The xyloglucan of the hemicellulose fraction soluble in 4% KOH may thus be involved in cell wall loosening which makes cell wall expansion possible during hypocotyl growth. 相似文献
The changes in the molecular weight distribution of water-soluble hemicelluloses and xyloglucan during hypocotyl growth of intact seedlings of Pinus pinaster Aiton were investigated. The mass-average molecular weight of total polysaccharides of the hemicellulose fraction soluble in 4% KOH dramatically increased during hypocotyl growth while xyloglucan slightly decreased. These phenomena were due to an increase in the degree of polymerization of an arabinogalactan and a slight depolymer-ization in the xyloglucan present in this fraction. In the hemicellulose fraction soluble in 24% KOH, xyloglucan increased its degree of polymerization from day 7 to 10 after which it decreased slightly. The xyloglucan of the hemicellulose fraction soluble in 4% KOH may thus be involved in cell wall loosening which makes cell wall expansion possible during hypocotyl growth. 相似文献
5.
A Shafiee M Vosooghi C G Francisco R Freire R Hernandez J A Salazar E Suarez S Sotheeswaran A A Gunatilaka 《Steroids》1987,49(4-5):397-402
The chemical synthesis and physical data of several new esters of testosterone (17 beta-hydroxyandrost-4-en-3-one), which contain either a halogeno or an alkoxy substituent in the acid chain, are reported. 相似文献
6.
S S Suarez 《Biology of reproduction》1987,36(1):203-210
Sperm transport and motility were studied through the transparent walls of the mouse oviduct by direct microscopic observation and videomicrography. Observations were made on excised female tracts 1-2 h post-coitus (pc) and 1-2 h before and after the approximate time of ovulation. Motile sperm were seen at the uterine entrance to the uterotubal junction (UTJ) in all females at 1-2 h pc, but in fewer females at later times. The intramural UTJ was usually constricted and held few sperm. The extramural UTJ and adjacent lower isthmus contained many motile sperm at 1-2 h pc. Apparently, the column of sperm moved upwards because in some females, sperm were found in the upper isthmus and not in the UTJ at the later time points. Few sperm were seen in the ampulla in the periovulatory period, and none at 1-2 h pc. There appeared to be two mechanisms retaining sperm in the lower oviduct: immobilization and adherence to the epithelium. Columns of immotile sperm were seen in the lower isthmus of some females. Motile sperm usually appeared to adhere by their heads to the oviductal epithelium, only occasionally breaking free to move vigorously about the lumen. 相似文献
7.
A C Enders I K Liu J Bowers K C Lantz S Schlafke S Suarez 《Biology of reproduction》1987,37(2):453-466
Fertilization and early development in the horse were studied by recovering oviductal ova at various times after postovulatory mating. Ova collected between 7 and 22 h post coitum (pc) were examined for evidence of fertilizing sperm, cellular changes accompanying fertilization, and pronuclear development. Five ova collected between 7 and 9 h pc contained a marginal metaphase plate, but had no indication of sperm components; three of these, however, showed reduced numbers of cortical granules. Two activated ova (10 and 14 h pc) were in telophase of the second meiotic division, following incorporation of the fertilizing sperm. The fertilizing sperm was situated in a slight elevation; the nucleus was expanding but lacked a nuclear envelope. The pronuclear stage in the horse began as early as 12 h pc, and lasted at least until 21 h pc. Sperm tail remnants were seen in 5 of 7 pronuclear-stage ova, although the crowding of the cytoplasm with clusters of lipid and vacuoles made discerning sperm tail remnants difficult. The spindles of the metaphase stage of the second meiotic division were oriented radially, that is, at right angles to the cell surface, in all but one ovum, so this orientation is not a response to fertilization. 相似文献
8.
In an attempt to show that the open field can still be used as a valid measure of fear, Jones (1983) has reported a failure to replicate some of our findings. The present studies show that this was due to procedural and methodological differences. For instance, we found that birds tested in a novel environment behaved quite differently from those, as in Jones' case, which were placed in one resembling the home cage. Moreover, birds housed in isolation for two days prior to testing reacted differently than those, as again in Jones' case, which were reared in isolation from hatching to the time of testing. The results were interpreted as being consistent with our view that open-field behaviour reflects a conflict between the need to reinstate contact with conspecifics on the one hand, and evade predation on the other. 相似文献
9.
Z Suarez de Mata M E Zarranz R Lizardo H J Saz 《Archives of biochemistry and biophysics》1983,226(1):84-93
2-Methylacetoacetyl-CoA and 3-keto-2-methyl pentanoyl-CoA have been proposed to be intermediates in the synthesis of 2-methylbutyrate and 2-methylvalerate, respectively, by Ascaris lumbricoides muscle. These volatile acids are major fermentation products of Ascaris metabolism. 2-Methylacetoacetyl-CoA reductase has been purified 532-fold from Ascaris muscle to yield a homogeneous preparation which contained a single protein species as observed on discontinuous polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. The purification procedure utilized subcellular fractionation, affinity chromatography on NAD+ agarose, and ion-exchange chromatography on DEAE-cellulose. A constant activity ratio for ethyl 2-methylacetoacetate and acetoacetyl-CoA was observed during purification, indicating that the same enzyme catalyzed both reactions. In addition, the purified protein catalyzed the NADH-dependent reduction of ethyl-3-keto-2-methyl pentanoate at essentially the same rate as it did ethyl 2-methylacetoacetate. The purified enzyme is a basic protein with an isoelectric point of 8.45 at 4 degrees C. The molecular weight of the native protein (Mr = 64,000 by exclusion chromatography) and the size of the subunit (Mr = 30,000 by dodecyl sulfate-polyacrylamide electrophoresis) indicate that the enzyme is composed of two subunits of the same molecular weight. Substrate-specificity studies, undertaken with the purified protein, demonstrated that the ethyl esters can substitute for the coenzyme A derivatives but this substitution results in an active substrate only when a branched 2-methyl group is present. The straight-chain ethyl ester is inactive. Kinetic constants for the substrates and nucleotides were determined. The role of the CoA esters as the physiological substrates for the Ascaris enzyme is substantiated. When assayed in the reductive direction with ethyl 2-methylacetoacetate as substrate, the activity of the purified enzyme was inhibited not only by coenzyme A as previously reported, but also by acetyl-CoA. The physiological implications of these inhibitions are discussed. 相似文献
10.
Movement characteristics and acrosomal status of rabbit spermatozoa recovered at the site and time of fertilization 总被引:3,自引:0,他引:3
Rabbit spermatozoa were recovered from the oviductal ampullae 11 h postcoitus by an oil microflush technique. Their movement was evaluated in the ampullar fluid, or in ampullar fluid diluted with in vitro fertilization medium, in slide preparations which were approximately 25 micron or 100 micron deep. The movement of these sperm was compared with the movement of ejaculated sperm in diluted semen. Movement parameters measured from videotapes recorded by a high-speed camera were coded according to treatment and entered into a microcomputer for statistical analysis. A total of 157 spermatozoa were recovered from the oviducts of 16 does: 152 were motile and 126 were free-swimming. Nearly all of the free-swimming sperm swam in trajectories whose average paths were circular. The flagellar beat pattern of the circular swimmers was asymmetric and nearly planar, and the sperm did not roll. Spermatozoa observed in 25-micron slide preparations produced smaller flagellar bends than sperm swimming in 100-micron preparations and tended to swim in larger circles which were oriented in the plane of the slide. Spermatozoa observed within the cumulus matrix moved in a slow, erratic, sinuous manner, but resumed rapid circling upon leaving the matrix. It was concluded that the ampullar sperm were hyperactivated, retaining this physiological condition as they entered the cumulus. The movement qualitatively resembled that of hyperactivated guinea pig and hamster spermatozoa because these species effectively swim in circles. In contrast, 80% of the ejaculated spermatozoa swam in linear trajectories, resulting from relatively symmetrical, flagellar beat patterns. The percentage of rolling spermatozoa and the rolling frequencies were less in the 25-micron than the 100-micron slide preparations. Thus, the movement parameters of both ampullar and ejaculated spermatozoa were affected by the geometry of their observation chambers. This influence should be taken into account when observing sperm motility in vitro. It could also be important in vivo, where changes in sperm movement in response to epithelial surfaces might provide an advantage for reaching the cumulus mass. Ninety-eight percent of the motile ampullar sperm were observed to have acrosomes, including all spermatozoa found within the cumulus matrix. 相似文献