The distribution and time dependence of total phosphorus (TP), dissolved inorganic phosphate (PO4P), total nitrogen (TN), chlorophyll a (Chl), dichromate oxidizability (CODCr), permanganate oxidizability (CODMn), water colour (Col) and transparency (SD), pH, dissolved oxygen (O2) and oxygen saturation (O2%) in the surface water of Lake Peipsi-Pihkva are studied by using 65-parameter regression models with the help of the SAS system. The yearly means, polarity and seasonal dependence of each investigated parameter during 1985–1994 are estimated from fitted models. The bulk of data consists of 456 to 1149 measurements per parameter. L. Peipsi-Pihkva appears to be polar with respect to the majority of the studied parameters. The content of TP, PO4P, TN, Chl, CODCr, CODMn, and Col decrease from south to north, while SD has an opposite trend. pH, O2, and O2% are quite uniform all over the lake. L. Peipsi is eutrophic, L. Pihkva is hypertrophic. The lake is influenced by significant yearly and seasonal changes. It is concluded that the Velikaja River is the main source of pollution for L. Peipsi-Pihkva. 相似文献
Diel vertical migration (DVM) and diel feeding rhythm of two cladocerans, Daphnia longispina and Bosmina coregoni were investigated at the pelagic area of Lake Toya (Hokkaido, Japan) in May, August and October 1992. Both species performed nocturnal DVM. The amplitude of DVM, however, became smaller from May to October. Such seasonal variations in DVM could not be explained by light penetration and/or water temperature. The two species had a clear feeding rhythm; they fed at night in May and October but also after sunrise in August. These feeding rhythms appeared to be related to the light-dark cycle, but were not necessarily associated with their DVM. We suggest that the diel feeding rhythm and DVM are regulated independently by light cues. 相似文献
Investigations on the leachate bioavailability, leaching rate, and lactic acid accumulation properties of plastic composite supports (PCS) were essential for large-scale or long-term lactic acid fermentation. Leachates from PCS and polypropylene discs (controls) were analyzed by the micro-Kjeldahl method; by absorbances at 260, 275, and 280 nm; and by bioassays with Lactobacillus casei subsp. rhamnosus (ATCC 11443). The amount of leached nitrogen in a 20-ml initial soaking solution had a high correlation with the soaking solution's cell density (r = 0.87) and absorbance at 260 nm (r = 0.95). Leaching rates of various PCS were evaluated by 20 20-ml simulated repeated-batch fermentations (RBF). PCS with only yeast extract as the minor agricultural ingredient had a high leaching rate and leached out 51 to 60% of the total nitrogen during the first RBF. PCS blended with dried bovine albumin, dried bovine erythrocytes, and/or soybean flour had slowed nutrient leaching (20 to 30% of the initial leached nitrogen). Hence, they could still maintain 1 g of lactic acid per liter and measurable cell density (absorbance at 620 nm, 0.4 to 0.6) at the 20th 20-ml RBF. Lactic acid accumulation properties of PCS were evaluated by soaking the supports in a 30% lactic acid solution for 72 h at 45(deg)C. The lactic acid-soaked supports were rinsed three times and then heat treated (121(deg)C, 15 min) in 15 ml of deionized water. The results showed that lactic acid accumulation in PCS was mainly due to absorption and had no correlation with lactic acid production or biofilm formation. 相似文献
A Chinese landrace of barley, Mokusekko 3, is unique in being completely resistant against all strains of barley yellow mosaic
virus (BaYMV). The present investigation revealed that the resistance of Mokusekko 3 is governed by two recessive genes. As
one of the resistance genes was known to be tightly linked with alleles at the Est complex locus, consisting of the Est1, Est2 and Est4 loci for esterase isozymes, each of the resistance genes could be separated by means of marker-assisted selection using an
isozyme allelic combination as a marker. One of the resistance genes, ym1, is linked to K (hooded lemma) and gl3 (glossy leaf 3) with recombination values of 25.3% and 9.7% respectively, and these three genes are located in the order
K-gl3-ym1 on chromosome 4. Another newly designated resistance gene, ym5, is linked to alleles at the Est complex locus and cu2 (curly growth 2), with recombination values of 1.9% and 19.5% respectively, in the order cu2-Est-ym5 from proximal to distal on the long arm of chromosome 3. The complete resistance of Mokusekko 3 is caused by combining two
resistance genes, ym1 and ym5. However, almost all the “resistant” cultivars derived from crosses with Mokusekko 3 are susceptible to the recently detected
strain BaYMV-III in Japan, since they contain only one resistance gene, ym5. Marker-assisted selection to combine resistance genes into a cultivar is discussed for the breeding of stabilizing resistance
to BaYMV.
Received: 23 September 1996 / Accepted: 8 November 1996 相似文献
Several recent studies have suggested seemingly contrasting roles of SIRT2 in inflammation: Our previous cell culture study has indicated that SIRT2 siRNA-produced decrease in SIRT2 levels can lead to significant inhibition of lipopolysaccharides (LPS)-induced activation of BV2 microglia, suggesting that SIRT2 is required for LPS-induced microglial activation. In contrast, some studies have suggested that SIRT2 deficiency can lead to increased inflammation. In our current study, we used a mouse model of neuroinflammation to determine the roles of SIRT2 in LPS-induced inflammation. We found that administration of SIRT2 inhibitor AGK2 can significantly decrease LPS-induced increases in CD11b signals and the mRNA of TNF-α and IL-6. We further found that AGK2 can block LPS-induced nuclear translocation of NFκB. In addition, our study has shown that AGK2 can decrease not only LPS-induced increase in TUNEL signals—a marker of apoptosis-like damage, but also LPS-induced increases in the levels of active Caspase-3 and Bax. Collectively, our current in vivo study, together with our previous cell culture study, has suggested that SIRT2 is required for LPS-induced neuroinflammation and brain injury.