Biosystematics and genetic relationships of Solea aegyptiaca and S. senegalensis

The isoenzymes from seven populations of Solea senegalensis or aegyptiaca were compared et 24–30 loci, six of which display significant differences in their allelic frequencies. In addition, these populations were compared to six other Soleidae species, namely Solea vulgaris, S. impar, S. lascaris, S. lutea, Michrochirus azevia, and M. variegatus. It was shown that S. senegalensis and S. aegyptiaca can be separated into two distinct genetic groups. Their high genetic similarity in comparison with the other species of Soleidae studied suggests that they have a common origin. The systematic status (species or semispecies) of these taxa could not, however, be elucidated. The high degree of genetic polymorphism observed in the regions where the two taxe are found together suggests that there still is some gene flow between them. However, this could be due to selection.     

Chromium picolinate supplementation improves insulin sensitivity in Goto-Kakizaki diabetic rats

Chromium picolinate (CrP) supplementation has been studied as a potential therapy of insulin resistance and lipid abnormalities. There have been some reports involving chromium supplementation in patients with diabetes, but the results are varied. The present study was conducted to assess the effects of CrP on insulin sensitivity and body weight in Goto-Kakizaki (GK) diabetic rats. We supplemented normal Sprague-Dawley (SD) rats and GK diabetic rats with supplemental CrP, 100 mg/kg/day once a day for 4 weeks. In the normal SD rats, the mean body weight of the control group increased by 50.5%, whereas that of the CrP-treated group increased by 65.9% (P < 0.05 vs control). Similarly, in the diabetic GK rats, CrP supplementation showed increased weight gain compared to the control group (133.4% vs 119.6% of the baseline weight, P < 0.01). Glucose tolerance tests (GTT) [ip injection of glucose; 2 g/kg] and insulin sensitivity tests [SQ injection of insulin (5 U/kg) plus ip injection of glucose (30 min after insulin injection)] were conducted. During insulin sensitivity tests at the end of treatment, the glucose levels were significantly lower in CrP-treated rats compared with the control rats (AUC_0→120; 113.1 ± 32.0 vs 170.5 ± 49.0 mg-min/mL, P < 0.05). During GTTs, the glucose levels and insulin concentrations in the CrP-treated rats were not different from those in the control rats.

The results of these studies suggest that CrP supplementation in GK diabetic rats leads to increase of weight gain and improvement of insulin sensitivity. This raises the possibility that CrP supplementation can be considered to improve carbohydrate metabolism in patients with type 2 diabetes mellitus.     

Isolation and characterization of Histophilus somni (Haemophilus somnus) in semen samples of rams with epididymitis

Histophilus somni (Haemophilus somnus) has been reported as the cause of epididymitis in rams. This bacterium has also been found in the preputial mucosa of rams without epididymitis lesions. H. somni is a bacterium that is difficult to characterize, since it is a pleomorphic Gram-negative bacilli of characteristics similar to Actinobacillus seminis, which is also found in ram epididymitis lesions. The objective of this work was to determine if H. somni (H. somnus) is involved in cases of sheep epididymitis. A clinical examination was performed in 160 rams, extracting semen by electro-ejaculation of 28 of them, which had epididymal lesions. The penis was exteriorized in order to avoid prepuce contamination. The semen samples were cultivated in chocolate agar in a 10% CO₂ environment. Two strains were isolated in pure culture with a colony morphology and microscopy similar to H. somni (H. somnus). These were identified using the API 20 E system, using as a control the reference strain of H. somnus (2336ATCC). One of the isolates (129H) resulted identical to the reference strain and the other (827) presented differences in the arginine decarboxylase, H₂S, catalase and inositol reactions, although these differences have been reported (in strains isolated from different geographic origins, animal species and anatomical region). To characterize the isolates, an electrophoretic analysis of total proteins was performed (PAGE–SDS) finding identical profiles between the reference strain of H. somnus and isolate 129H and similar in relation to isolate 827. The amplification of a fragment of approximately 407 bp was observed in the 129H isolate and the ATCC strain, but not in 827. In other samples, isolations were made of Brucella ovis, Corynebacterium spp., Staphylococcus and other pleomorphic Gram-negative bacilli similar to A. seminis. Therefore, it has been confirmed that H. somni is present in the reproductive tract of rams and it could be involved in the presentation of ovine epididymitis. It is important that we underline that this is the first report of H. somni isolation in Mexico from ram semen samples.     

The induction of sister-chromatid exchanges in Chinese hamster ovary cells by K-region epoxides and some dihydrodiols derived from benz[a]anthracene, dibenz[a,c]anthracene and dibenz[a,h]anthracene

Experiments were performed to investigate the effects of 3 polycyclic aromatic hydrocarbons, benz[a]anthracene, dibenz[a,c]anthracene and dibenz[a,h]anthracene and K-regio epoxides and some of their related dihydrodiols on the chromosomes of Chinese hamster ovary cells in vitro. Of the 3 hydrocarbons only benz[a]anthracene showed any activity in inducing sister-chromatid exchanges. The K-region epoxide and the 3,4-dihydrodiol have been found to be more active than the corresponding K-region or the other non K-region dihydrodiols derived from benz[a]anthracene. Athough dibenz[a,c]anthracene was almost inactive, the K-region 5,6-epoxide and all 3 possible dihydrodiols, the 1,2-, 3,4- and 10,11-diols were active in inducing increased numbers of sister-chromatid exchanges in the chromosomes of these cells. The 3,4-dihydrodiol of dibenz[a,h]anthrecene was also active in inducing sister-chromatid exchanges whereas the 1,2- and 5,6-dihydrodiols were only weakly active. This study provides some support for the suggestiion that the activation of these 3 hydrocarbons proceeds by the metabolic conversion of non K-region dihydrodiols into vicinal diol-epoxides.     

Crossed immunoelectrophoretic analyses of antigens from Trypanosoma lewisi and Trypanosoma musculi

Trypanosoma lewisi and Trypanosoma musculi were collected from immunosuppressed infected hosts and extracted with phosphate buffered saline. Antisera were obtained from rats repeatedly infected with T. lewisi or mice repeatedly infected with T. musculi. Cellular antigens (CAg) present in the extracts of the parasites were analyzed by microimmunodiffusion (MID), crossed immunoelectrophoresis (CIE) and tandem crossed immunoelectrophoresis (TCIE). Trypanosome extracts were absorbed with the heterologous hyperimmune antisera to examine shared and unique antigens of the parasites.

Extracts of T. lewisi formed four precipitin lines when reacted with hyperimmune rat antiserum and three precipitin lines were detected by mouse anti-T. musculi serum in MID analyses. T. musculi extract formed two precipitin lines with mouse hyperimmune serum and two precipitin lines with rat anti-T. lewisi serum in the MID tests. When T. lewisi was reacted with the homologous hyperimmune rat antiserum in CIE, 14 precipitin peaks developed, while T. musculi extract formed eight peaks with homologous mouse hyperimmune serum. Seven precipitin peaks developed when T. lewisi extract was reacted with the mouse antiserum and T. musculi extract formed eight peaks during its electrophoretic migration into rat anti-T lewisi serum. TCIE clearly showed that five T. lewisi CAg could not be detected in the T. musculi extract by the rat antiserum, while mouse anti-T. musculi serum formed six precipitin peaks with the T. lewisi extract and seven peaks with the homologous extract. One of the CAg present in the T. musculi extract was not found in the T. lewisi extract. Absorptions of the extracts with heterologous antisera and subsequent CIE against the homologous antisera indicated three of the CAg of T. lewisi were not shared by T. musculi, while a single antigen of T. musculi was not detected in T. lewisi. Although concentrations of antibodies in each of the antisera and CAg in the parasite extracts were not equivalent, the data indicated that a minimum of eight CAg are shared by these rodent trypanosomes and at least three antigens appeared to be unique to T. lewisi and a single antigen to T. musculi.     

Chloroplast DNA and the determination of species status in the Disa tripetaloides complex (Orchidaceae), and its relationships to three species Racemosae, section Disa

Disa cardinalis and three populations within the D. tripetaloides species complex contain variation in their chloroplast DNA (cpDNA) variability. All four taxa possessed unique cpDNAs and sequence divergence values ranged from 0.34 to 1.03%. A phylogeny of these genomes was reconstructed, along with the genomes of three other species, D. racemosa, D. uniflora and D. venosa, all of which are also section Disa and series RAcemosae, to determine the relationship of these closely related species to the D. tripetaloides complex. A phylogeny of the taxa using morphological data was also reconstructed. Outgroup comparison was made with D. sagittalis, a member of section Coryphaea. Although the molecular and morphological data were not completely congruent, both data types revealed D. cardinalis, rather than D. tripetaloides ssp. aurata, to be more closely allied with D. tripetaloides ssp. tripetaloides, suggesting that D. tripetaloides ssp. aurata should be elevated to species rank. Additionally, the high sequence divergence observed between the Natal and Cape populations, coupled with their geographical isolation and alternate flowering seasons, suggests that these two D. tripetaloides ssp. tripetaloides populations may, in fact, be more appropriately ranked as subspecies.     

The tegument of the monogenean gill parasites Dactylogyrus amphibothrium and D. hemiamphibothrium

The general features of the tegument of Dactylogyrus amphibothrium and D. hemiamphibothrium, gill parasites of the freshwater fish Acerina cernua, resemble those of other monogeneans. However, in D. amphibothrium the tegument bears spike-like structures associated with tegumental sacs and these have not previously been reported in monogeneans. The origin of the sacs and the possible functions of the spikes and sacs are discussed. It has been found that the tegument covering the two pads located on the ventral surface of D. amphibothrium does not differ in structure from the general body tegument; the pad regions are elevated above the general body surface because of the presence of large glandular sub-tegumentary organs which communicate with the receptaculum seminis. This indicates that the pads play a part in the reproductive biology of the parasite. In spite of the fact that the micro-environments of D. amphibothrium and D. hemiamphibothrium are the same or broadly similar, D. hemiamphibothrium has no spikes, tegumentary sacs or glandular pads and has only two kinds of tegumentary secretory inclusion compared with three kinds in D. amphibothrium. One of the three kinds of cyton in D. amphibothrium is restricted to the ventro-lateral regions of the posterior half of the body. The tegument of both D. amphibothrium and D. hemiamphibothrium differs from that of other adult monogeneans so far investigated in the presence of granular endoplasmic reticulum in the outer syncytial layer.     

细胞自噬在大鼠缺血/再灌注肺损伤中的调控作用

目的: 探讨细胞自噬在大鼠缺血/再灌注肺损伤中的作用。方法: 随机将40只SD大鼠分为5组(n=8),分别为 ① 假手术组(Sham组):只开胸3.5 h;② 缺血/再灌注组(I/R组):开胸夹闭肺门缺血0.5 h后再灌注3 h;③ 溶剂组(DMSO组):术前1 h腹腔注射DMSO溶液;④自噬激动剂组(Rap组):术前腹腔注射雷帕霉素溶液;⑤自噬抑制剂组(3-MA组):术前1 h腹腔注射3-MA溶液;后三组的其余操作同I/R组。实验结束后处死大鼠,取肺组织,记录并计算肺组织湿/干重比(W/D)、总肺含水量变化(TLW) ,光镜和电镜观察肺组织及细胞形态,计算肺泡损伤率(IAR),Western blot检测自噬相关蛋白的表达情况。结果: 相对于sham组,其余四组肺W/D、TLW、IAR均明显升高,自噬相关蛋白表达明显上升,p-AMPK、Beclin 1、LC3 II 蛋白明显增多,p-mTOR、p62蛋白明显减少(P＜0.05或P＜0.01),光镜下其余各组肺组织有不同程度的水肿渗出,肺泡结构紊乱,电镜下细胞超微结构损伤加重,部分可见自噬小体;与DMSO组相比,3-MA组肺W/D、TLW、IAR明显下降(P＜0.05或P＜0.01),自噬相关蛋白表达明显下降,肺间质水肿较轻,细胞渗出较少,细胞超微结构损伤减轻,未见自噬小体。而I/R、DMSO、Rap组的各项指标变化无统计学差异(P＞0.05)。结论: 肺缺血/再灌注可诱发细胞自噬增强,从而引起大鼠肺损伤。     

The Aspergillus niger carbon catabolite repressor encoding gene, creA

In order to undertake a comparative analysis of carbon catabolite repression in two Aspergillus species, the creA gene has been isolated from A. niger by cross hybridization, using the cloned A. nidulans gene. The A. niger gene has been shown to be functional in A. nidulans by heterologous complementation of the creA204 mutation of A. nidulans. Overall, the genes show 90% sequence similarity (82% identity) at the amino acid (aa) level. There were some striking similarities between the aa sequences encoded by the two fungal creA genes and two genes involved in carbon catabolite repression in Saccharomyces cerevisiae. The zinc-finger regions showed 96% similarity (84% identity) with the zinc-finger region of the MIG1 gene of S. cerevisiae. The CREA protein contains a stretch of 42 aa that is identical in A. niger and A. nidulans, and these show 81% similarity (33% identity) with a region of the S. cerevisiae RGR1 gene.     

Inhibitory effects of Hymenaea and Copaifera leaf resins on the leaf fungus, Pestalotia subcuticularis

Leaf resins in the leguminous genera Hymenaea and Copaifera may play a role in restricting infection by the associated leaf fungus, Pestalotia. We tested this hypothesis by assessing growth of the geographically widespread Pestalotia subcuticularis presented with different compositions of resins. Leaf resins of Hymenaea and Copaifera are composed of the same suite of sesquiterpene hydrocarbons, but these vary quantitatively to form discrete compositional patterns among individuals and populations. Leaf resins may also contain sesquiterpene oxides; caryophyllene oxide, which may have been formed from the caryophyllene precursor common in these resins, inhibited fungal growth in vitro.     

乳杆菌对致病假单胞菌的抑制作用研究进展*

假单胞菌污染事件在临床就医和日常饮食中频发,屡次产生致病、致死等恶劣后果,有效抑制致病假单胞菌并降低其耐药性作为解决该问题的关键手段,是目前的研究重点。相关研究表明益生菌等天然活性成分对假单胞菌产生多方面影响,以应用范围最广的益生菌——乳杆菌为例,综合国内外最新研究进展,论述了乳杆菌对假单胞菌的生物膜结构、生长活性、生物毒性、黏附细胞表面能力及被假单胞菌感染后的小鼠等产生的影响。深入挖掘乳杆菌等益生菌及其代谢产物成分的作用机制,是防治假单胞菌等微生物污染和感染的关键。     

Predation by Callinectes sapidus (Rathbun) within Spartina alterniflora (Loisel) marshes

This study examined predation by the blue crab, Callinectes sapidus Rathbun, within intertidal Spartina alterniflora (Loisel) marshes of Dauphin Island, Alabama. Species and size preferences displayed by the predator when foraging within the marsh were investigated using nektonic, epifaunal, and infaunal prey populations including Fundulus similis Baird and Girard, Littorina irrorata Say, and Geukensia demissa Dillwyn.

Short-term field experiments involving the use of predator inclusion cages, in which the relative abundances of all prey species and the density of macrophyte vegetation were manipulated, indicated that mean mortality differed significantly among species. Blue crabs exhibited a distinct species preference for Littorina, and to a lesser extent, for Fundulus. However, the predator rarely choses infaunal individuals. Within predator inclusion cages, size selection by the crabs among three size classes of each prey was evident for Littorina and Fundulus but not for Geukensia. Blue crabs tended to select intermediate-sized snails and large fish while not exhibiting a size preference for infaunal bivalves.

In the marsh, mean percentage of the Littorina population within the 14–18 mm size class exhibited an increased mortality as compared to two other size classes, which was negatively correlated with increasing tidal height. Such a relationship may have been due to a decreasing gradient of crab predation associated with increasing tidal height. Geukensia size class distributions showed little evidence of differences along the tidal height gradient. No data are available for Fundulus, a mobile species which would not experience such differential predation along a marsh gradient.

In comparing crab predation patterns among prey species, it is apparent that Callinectes utilizes prey species differentially. Such differential utilization may be based on optimization of energy yield and minimization of energy expenditure. Thus, the preference of blue crabs for nektonic and epifaunal prey is hypothesized to be the result of a smaller energy expediture as a result of the crab's visual evaluation of these prey. Infaunal prey species (e.g., Geukensia) require a greater energy investment because of the necessity of excavating the prey item. Such prey also allow little selection by size because of being cryptic.     

Deacidification by Schizosaccharomyces: interactions with Saccharomyces

The objective of this work was to study the partial consumption of malic acid in a semi-synthetic medium by Schizosaccharomyces yeast under wine-making conditions. The aim was to control the extent of deacidification by stopping the activity of Schizosaccharomyces by the addition of Saccharomyces yeast at different delayed intervals of time. This was thought possible because the Schizosaccharomyces yeasts are much more slower than the Saccharomyces yeasts and may be inhibited by the latter. In fact, the opposite was observed. Schizosaccharomyces exhibited a amensal effect against Saccharomyces: the Saccharomyces growth was inhibited by Schizosaccharomyces, this inhibition being proportional to the Schizosaccharomyces concentration, reversible, and sensitive to temperature. Such interactions similar to a killer effect have not been described before. At the same time a competition towards sugar was noted, being negative for Schizosaccharomyces since these yeasts have slower metabolic rates. Nevertheless, total demalication was nearly always possible because sufficient concentrations of Schizosaccharomyces were always reached. The delayed inoculation of Saccharomyces after Schizosaccharomyces was not a good solution to obtain partial deacidification.     

The Peniophorella praetermissa species complex (Basidiomycota)

The corticioid basidiomycete Peniophorella praetermissa has long been regarded as a morphologically variable species complex. An ITS-based phylogenetic study based on a worldwide sampling was carried out using parsimony and Bayesian inference. The resulting trees feature three major clades, further divided into well-supported subclades. These could be considered as distinct species, a contention that is further supported by crossing test data. Only two out of the eight phylogenetic lineages identified can be distinctly morphologically characterized: P. odontiaeformis and P. subpraetermissa. P. odontiaeformis is an odontioid species with a paleotropical distribution whereas the taxa in the remaining subclades have smooth basidiomata and are distributed in temperate areas. P. subpraetermissa is known only from the type collection and is distinguished microscopically by its reddish brown apically encrustated cystidia. Taxa in the remaining subclades are impossible to distinguish from each other morphologically, and therefore, are viewed as a species complex, P. praetermissa s. lat. One of the subclades, which is widely distributed but restricted to the Northern hemisphere, is proposed to represent P. praetermissa s. str. An epitype is selected from the same area as the holotype, among the specimens studied here. However, the geographically most widespread clade with many representatives from both hemispheres is here referred to as P. pertenuis, a taxon that was previously considered a synonym to P. praetermissa.     

Population studies in Artemisia tridentata ssp. vaseyana: Chromosome numbers and sesquiterpene lactone races

The sesquiterpene lactones and chromosome numbers for three chemical races of Artemisia tridentata ssp. vaseyana have been examined from four populations in western Montana. TLC analysis of the sesquiterpene lactones in the seeds and seed producing parents demonstrated that genetic exchange does occur between sympatric sesquiterpene lactone chemical races. However, other evidence suggests that introgression between these races is restricted to zones of sympatry. There appears to be no correlation between chromosome numbers and sesquiterpene lactone races.     

The metabolism of dihydrotachysterols: Renal side chain and non-renal nuclear hydroxylations in vivo and in vitro

The metabolism of dihydrotachysterol (DHT), a hydrogenated analogue of vitamin D, has been studied in vivo using man and rat and in vitro using the perfused rat kidney, and hepatoma (3B) and osteosarcoma (UMR-106) cell lines. In vivo a large number of metabolites appeared in the plasma of rats given DHT₂ and DHT₃. Of particular interest was a compound more polar than 25-hydroxy-DHT, which has been designated compound H. Further study of this compound showed that it was composed of two components, one (Ha) being in much lower concentration than the other (Hb). The production of T2/H (peak H from DHT₂) was demonstrated in human plasma after administration of oral DHT₂. Comparison of the metabolites formed in vivo with those isolated from the rat kidney perfused with 25-hydroxy-DHT₃ in vitro showed that 25-hydroxy-DHT₃ was metabolized along two metabolic pathways previously described for vitamin D, culminating in the production of 25-hydroxy-DHT₃-23,26-lactone and 23,25-dihydroxy-24-oxo-DHT₃. The osteosarcoma cell line metabolized 25-OH-DHT₃ in vitro along the same two metabolic pathways already demonstrated in the perfused rat kidney. More polar metabolites than compound H seen in rat plasma in vivo were shown to be metabolites of compound H and similar metabolites were also produced in the osteosarcoma cell line from chemically synthesized 1,25-dihydroxy-DHT₃. The hepatoma cell line 25-hydroxylated DHT and no feed-back inhibition was observed. Use of the hepatoma cell to 25-hydroxylate a number of chemically synthesized 1-hydroxy-DHTs indicated that compound Ha was indistinguishable from 1,25-dihydroxy-DHT whereas compound Hb is possibly 1β,25-dihydroxy-DHT. Studies with the VDR in both chick gut and calf thymus indicated that 1,25-dihydroxy-DHT is very effective in displacing radiolabelled 1,25-dihydroxyvitamin-D₃ and is thus most likely to be the calcaemic metabolite of DHT.