Mechanism of inhibition caused by long-chain fatty acids in anaerobic digestion process

The inhibitory effect of long-chain fatty acids on the anaerobic digestion process was examined in batch experiments using synthetic substrates. The addition of long-chain fatty acids caused the appearance of the appearance of the lag period in the methane production from acetate and in the degradation of both long-chain fatty acids and n-butyrate. Methane production from hydrogen proceeded without lag period although its rate was lowered. Fermentation of glucose was not inhibited. Neutral fat in the whole milk was easily hydrolyzed to long-chain fatty acids, which brought about the inhibition. The addition of calcium chloride reduced the inhibitory effect of long-chain fatty but it did not do so after the culture had been exposed to long-chain fatty acids for more than several hours. The addition of calcium carbonate could not reduce the inhibition because of its insolubility.     

Analysis of common antigen of flagella in Bacillus cereus and Bacillus thuringiensis

Abstract Flagellar antigen of Bacillus cereus H.1 was purified and tested for serodiagnostic antigen by ELISA. The antibody against the flagellar antigen of B. cereus H.1 reacted not only with the homologous specific antigen but also reacted with the flagellar antigens of 23 strains of B. cereus . This common flagellar antigen of B. cereus was found to be due to 61-kDa protein by SDS-PAGE and immunoblot assay. Monoclonal antibody H15A5 against common antigenic epitope of B. cereus also reacted with flagellar antigens of 21 strains of Bacillus thuringiensis by ELISA. This monoclonal antibody reacted with the 61-kDa protein of the flagella of B. cereus H.1 and H.2 and B. thuringiensis Kurstaki HD1, Alesti and Aizawai juroi by immunoblot analysis. These results indicated that the common antigenic epitope of the 61-kDa protein existed in the flagella both of B. cereus and B. thuringiensis .     

Primary Infection of Barley by Erysiphe graminis f. sp. hordei in Relation to Leaf-Age Dependent Resistance and the Roles of the Epidermis and Mesophyll in this Resistance

Abstract The infection frequency of both compatible and incompatible races of Erysiphe graminis f. sp. hordei decreased gradually with increasing leaf age on undetached primary barley leaves. The length of secondary hyphae of the compatible race was approximately the same regardless of age, but secondary hyphae were slightly longer on younger seedlings than on older seedlings in the case of the incompatible race. Both the infection frequency and length of secondary hyphae of the two races weredistinctly different. On composite sections produced by exchanging the epidermal layers of young and relatively mature primary leaves, the infection frequency of the compatible race was higher on the epidermis of young leaves than on the epidermis of older, leaves, regardless of which mesophyll was under the epidermis. The epidermis appears to play a major role in age-dependent resistance, while the mesophyll may act disparately by providing a factor promotive to mildew infection in addition to supporting the resistance function of the epidermis.     

Inhibition of ATPase Activity in Pea Plasma Membranes In Situ by a Suppressor from a Pea Pathogen, Mycosphaerella pinodes

A pathogenic fungus of pea, Mycosphaerella pinodes, secretesa so-called "suppressor" in its pycnospore germination fluid.The suppressor blocks the defense responses and induces localsusceptibility (accessibility) in pea plants to agents thatare not pathogenic in pea. The suppressor nonspecifically inhibitsthe ATPase activity in plasma membranes prepared from pea, soybean,kidney bean, cowpea and barley plants. However, cytochemicalstudies by electron microscopy indicate that the suppressorspecifically inhibits the ATPase in pea cell membranes, butnot in those of four other plant species tested. That is, thespecificity of the suppressor appears at the cell and/or tissuelevel, but is not evident in vitro. Furthermore, the inhibitoryeffect of the suppressor is temporary because the ATPase activityrecovers 9 h after the treatment. A similar effect was observedafter inoculation with M. pinodes but not with a nonpathogenof pea, M. ligulicola. The role of the suppressor in host-parasitespecificity is discussed. (Received April 9, 1991; Accepted August 6, 1991)     

Changes in proteoglycan composition during development of rat skin. The occurrence in fetal skin of a chondroitin sulfate proteoglycan with high turnover rate

Extraction of the skin of newborn rat yielded two populations of galactosaminoglycan-containing proteoglycan: a Mr = 111,000-200,000 dermatan sulfate proteoglycan (DS-PG) with a Mr congruent to 55,000 core glycoprotein and a Mr congruent to 10(6) chondroitin sulfate proteoglycan (CS-PGs) composed of two subpopulations with different size core-glycoproteins (Mr congruent to 480,000 and 520,000). Tryptic peptide mapping of chondroitinase-treated DS-PG and CS-PGs indicated that the peptide patterns observed with the two core molecules from CS-PGs were identical with each other but distinct from the peptide pattern of the DS-PG core molecule. It is likely therefore that the two forms of CS-PGs are derived from the same gene product by post-translational modification or partial degradation, but DS-PG is derived from a distinct gene product. Comparison of the concentration (hexuronate/DNA) of the proteoglycans in newborn and fetal rat skin showed an age-related change in proteoglycan composition; at 4 days before birth, the uronic acid proportions, DS-PG:CS-PGs, were about 14:1 and during the next 4 days, DS-PG increased 2.2-fold whereas CS-PGs decreased 4-fold. On a per DNA basis, the rate of [3H]serine incorporation into CS-PGs was 2.5 times the rate for DS-PG at 4 days before birth but decreased by 95% during the next 4 days. The rate for DS-PG also decreased but to a much lesser extent, so that by 2 days before birth, it began to exceed the rate for CS-PGs. The striking change in the concentration and labeling rate of CS-PGs can be interpreted either as a decrease of CS-PGs synthesis, or as an increase of CS-PGs breakdown, or both, a process which might be involved in the transition of extracellular matrix from a fetal type to a newborn or adult type.     

Fine structure and lectin histochemistry of the apical surface of the free neuromast of Lampetra japonica

The surface coat, ciliary process, and microvilli of the lamprey neuromast were examined with electron microscopy after tannic acid prefixation and lectin histochemistry. The neuromast was found to exist in the form of a dermal mound with a furrow in the middle. On the bottom of the furrow, the hair cell was characterized by a kinocilium and 15–20 stereocilia, arranged along the longitudinal axis of the furrow. Spanning structures were demonstrated between the kinocilium and stereocilia as well as between stereocilia. The surface coat, enhanced by tannic acid prefixation, was particularly rich over the surface of the supporting cell; by contrast, it was thin over the hair cell. Some lectins (PNA, GS-I, SBA, WGA) showed affinity to the surface coat of the supporting cell as well as the hair cell, and the others (RCA-I, MPA, ConA) showed affinity only to the supporting cell. These differences in the structure and affinities of the surface coat suggest an extracellular milieu highly specialized for the hair cell in this particular form of the mechanoreceptor.     

Aluminum Toxicity: A Case Study on Tobacco (<i>Nicotiana tabacum</i> L.)

Aluminum is an abundant metal in the earth’s crust that turns out to be toxic in acidic environments. Many plants are affected by the presence of aluminum at the whole plant level, at the organ level, and at the cellular level. Tobacco as a cash crop (Nicotiana tabacum L.) is a widely cultivated plant worldwide and is also a good model organism for research. Although there are many articles on Al-phytotoxicity in the literature, reviews on a single species that are economically and scientifically important are limited. In this article, we not only provide the biology associated with tobacco Al-toxicity, but also some essential information regarding the effects of this metal on other plant species (even animals). This review provides information on aluminum localization and uptake process by different staining techniques, as well as the effects of its toxicity at different compartment levels and the physiological consequences derived from them. In addition, molecular studies in recent years have reported specific responses to Al toxicity, such as overexpression of various protective proteins. Besides, this review discusses data on various organelle-based responses, cell death, and other mechanisms, data on tobacco plants and other kingdoms relevant to these studies.     

Stimulation of glycosaminoglycan sulfotransferase from chick embryo cartilage by basic proteins and polyamines

A soluble glycosaminoglycan sulfotransferase (3'-phosphoadenylylsulfate:chondroitin 4'-sulfotransferase, EC 2.8.2.5) from chick embryo cartilage has been prepared free from endogenous acceptor. The reaction with this enzyme preparation was stimulated by basic proteins and polyamines, the degree of stimulation being dependent on the chemical nature of both basic compounds and acceptor glycosaminoglycans. A maximum stimulation was obtained when protamine (basic compound) and chondroitin (acceptor) were involved in the reaction mixture at a molar ratio of protamine to repeating disaccharide units of chondroitin, 1:100. The stimulation of sulfotransferase activity by basic substances was much higher than that by Mn2+. However, increasing the Mn2+ concentration immediately reduced the stimulation by basic substances. The Km value for 3'-phosphoadenosine 5'-phosphosulfate of the sulfotransferase, when chondroitin was used as acceptor, was 1 . 10(-6) M in the presence of 25 microgram/ml protamine, compared to 2 . 10(-5) M in the absence of protamine. These observations indicate that the basic proteins and polyamines may interact with acceptor polysaccharide, thereby causing an increase in the affinity of the enzyme toward 3'-phosphoadenosine 5'-phosphosulfate.     

Separation and properties of five glycosaminoglycan sulfatases from rat skin.

Chondroitin sulfates, dermatan sulfate, heparan sulfate, heparin, keratan sulfate, and oligosaccharides derived from these sulfated glycosaminoglycans have been used for the measurement of sulfatase activity of rat skin extracts. Chromatographic fractionation of the extracts followed by specificity studies demonstrated the existence of five different sulfatases, specific for 1) the nonreducing N-acetylglucosamine 6-sulfate end groups of heparin sulfate and keratan sulfate, 2) the nonreducing N-acetylgalactosamine (or galactose) 6-sulfate end groups of chondroitin sulfate (or keratan sulfate), 3) the nonreducing N-acetylgalactosamine 4-sulfate end groups of chondroitin sulfate and dermatan sulfate, 4) certain suitably located glucosamine N-sulfate groups of heparin and heparan sulfate, or 5) certain suitably located iduronate sulfate groups of heparan sulfate and dermatan sulfate. Two arylsulfatases, one of which was identical in its chromatographic behaviors with the third enzyme described above, were also demonstrated in the extracts. These results taken together with those previously obtained from studies on human fibroblast cultures suggest that normal skin fibroblasts contain at least five specific sulfatases and diminished activity of any one may result in a specific storage disease.