Identification of Anguilla anguilla (L.) and Anguilla rostrata (Le Sueur) and their hybrids based on a diagnostic single nucleotide polymorphism in nuclear 18S rDNA

The variability of the nuclear 18S rDNA was examined for 10 species of freshwater eels: Anguilla anguilla, A. australis, A. dieffenbachii, A. japonica, A. marmorata, A. mossambica, A. nebulosa labiata, A. obscura, A. reinhardtii and A. rostrata. We observed that a single nucleotide polymorphism (SNP) separated A. anguilla and A. japonica from the remaining taxa. While this SNP marker may be used to identify hypothetical hybrids of A. japonica and sympatric eel species, we focused on Atlantic eels to evaluate the potential for this diagnostic chromosomal marker to discriminate between individuals of A. anguilla, A. rostrata and their hybrids.     

Extending the host range of the bioherbicidal fungus Colletotrichum gloeosporioides f. sp. aeschynomene

Spore formulations of the bioherbicidal fungus Colletotrichum gloeosporioides f. sp. aeschynomene (ATCC No. 20358) (CGA) were evaluated for control of three weed species: northern jointvetch (Aeschynomene virginica), Indian jointvetch (A. indica), and hemp sesbania (Sesbania exaltata) in greenhouse experiments. Mortality, dry weight reduction, and plant height reduction of A. virginica seedlings ranged from 98% to 100%, 15 days after inoculation with CGA in water, in an invert emulsion, or in Silwet L-77 surfactant. However, CGA in water caused no effects of these parameters on S. exaltata, and only slight effects on A. indica. A. indica and S. exaltata were also severely injured (mortality, dry weight and plant height reduction, 98–100%) by CGA in the invert emulsion or in Silwet L-77. The CGA in Silwet formulation incited severe disease development more rapidly than the invert emulsion or water formulations of CGA in all species. These results suggest that the host range of CGA can be expanded though formulation modification to enable this bioherbicide to control multiple weeds, thus making this product more economically acceptable.     

田菁种子中甘露糖磷酸变位酶（PMM）的纯化及其性质

利用 Sephadex G-200平板等电聚焦技术对田菁(Sesbania cannabina)种子中的 PMM进行了纯化。得到的 PMM 等电点为 pH5.0,在 SDS 聚丙烯酰胺凝胶电泳上表现为一条带,分子量为41 kD。酶活测定表明,PMM 的最适催化 pH 为7.3,其催化甘露糖-1-磷酸(M-1-P)到甘露糖-6-磷酸(M-6-P)反应的平衡常数为16.2。另外用酸水解法对田菁 PMM 的氨基酸组分进行了分折。     

Simultaneous RP-HPLC-PDA-RI separation and quantification of pinitol content in Sesbania bispinosa vis-à-vis harvesting age

Sesbania bispinosa belongs to the family Fabaceae contains appreciable percentage of antidiabetic cyclitol known as (+)-pinitol. A rapid high-performance liquid chromatography method has been developed for estimating the pinitol content in methanol extracts of S. bispinosa (roots, stems, leaves, flowers and pods) with respect to its harvesting age. Chromatographic separation was carried out on XBridge Amide column (250 mm x 4.6 mm, 3.5 μm coating) using isocratic elution of solvent system comprising water: acetonitrile (80:20) and water: acetonitrile (30:70) with 0.2% triethylamine at 30^°C. The RP-HPLC-PDA-RI and LC-MS/MS analyses have shown significant variations of pinitol content in roots, stems, leaves, flowers, and pods extracts of S. bispinosa with respect to a particular harvesting age. At pre-fruiting stage, the highest percentage of pinitol was detected in all the parts of the plant extracts (roots: 2.72%, stems: 2.81%, leaves: 2.32% and pods: 3.92%). Therefore, it is recommended to harvest the plant at pre-fruiting stage for getting highest amounts (0.16%) of total pinitol. As a result, the pinitol content might be employed as a reference marker to decide the harvesting age of S. bispinosa.     

Developing embryos of Sesbania sesban have unique potential to photosynthesize under high osmotic environment

This study has been carried out to investigate the photosynthetic activities in developing embryos of Sesbania sesban under a highly osmotic environment. In S. sesban, the embryo turns green/chlorophyllous at the early heart shape stage. Interestingly, despite being deeply embedded within the supporting tissues (several layers of pod wall, seed coat and endosperm) and developing in a highly osmotic environment, the growing embryo of the developing seed showed the presence of various components of photosynthetic machinery besides being chlorophyllous. The shade-adaptive nature of the photosynthetic machinery of the embryo is evident from (a) low chlorophyll a/b ratio, (b) photosystem (PS) II attaining maximal activity at low photon flux density and (c) lesser plastoquinone pool. The photosynthetic potential of the growing embryo seems to contribute towards seed filling as it has the potential not only to harvest light energy but also to fix CO2 as efficiently as other photosynthetic parts of S. sesban. In fact, ribulose-1,5 bisphosphate carboxylase purified from embryos manifested subunit composition similar to that of leaves. The PS II activity in leaves, cotyledonary leaves and pod wall declined sharply with increase in the level of NaCl and sucrose above 150 and 300 mmol, respectively. Amazingly, PS II activity in developing embryos was maximal in the presence of 250 mmol NaCl or 500 mmol sucrose and remained high even when NaCl and sucrose levels were increased to 500 and 1000 mmol, respectively. We hypothesize that the developing embryos have some factor(s) which protect(s) the photosynthetic machinery in an environment of high osmotic strength.     

A Soap Technique for Cell Separation to Study the Seed Coat of Sesbania punicea

A technique is described for separating plant cells used for morphological studies. The plant material is placed in a concentrated solution of olive oil castile soap for 1-2 days or more. The material is then thoroughly washed and placed between two glass slides. The upper glass slide is lifted from the lower one, then gently pressed down several times. Through this procedure Malpighian cells of the seed coat of Sesbania punicea. mesophyll cells of Euphorbia peplus and of Trifolium pratense and cortical cells of the aerial roots of Monstera deliciosa have been separated. Various shapes of the Malpighian cells of the Sesbania punicea seed coat can be observed along with intermediates.     

Behaviour and swimming performance of elvers of the American eel, Anguitta rostrata, in an experimental flume

Migrating elvers of the American eel, Anguilla rosirata , were examined in an experimental flume to determine the effect of water speed and presence of substrate on swimming performance. Use of the substrate as a resting area between movements increased with increasing water speed. The number of elvers moving in the boundary layer above the substrate was significantly greater than those moving in the water column. Swimming speed in the water column and along the substrate increased with water speed. Rate of progress over ground in the water column and boundary layer increased slightly with water speed initially, but subsequently declined in the boundary layer. Overall, swimming speed increased linearly with increasing water speed and net upstream progress remained constant with increasing water speed. Use of the boundary layer probably was restricted by the thickness of the layer as a function of water speed. The boundary layer should be used to maximize distance and minimize energy expense when migrating upstream. Elvers appear to use substrate to avoid free stream velocities and not as a medium for movement. Fifty per cent of all elvers tested in a chamber without substrate, which had no resting places, were unable to swim; thus migrations may be limited by the need to rest. The potential migration rate was estimated to approach 100m per day, based on movements in the substrate chamber.     

Plant gene expression during effective and ineffective nodule development of the tropical stem-nodulated legume Sesbania rostrata

The expression of plant genes during symbiosis of Sesbania rostrata with Rhizobium sp. and Azorhizobium caulinodans was studied by comparing two-dimensional PAGE patterns of in vitro translation products of poly(A)⁺ RNA from uninfected roots and stems with that of root and stem nodules. Both types of nodules are essentially similar, particularly when stem nodules are formed in the dark. We detected the specific expression of at least 16 genes in stem and root nodules and observed the stimulated expression of about 10 other genes in both nodules. Six of the nodule-specific translation products (apparent molecular masses around 16 kDa) cross-react with an antiserum raised against leghemoglobin purified from Sesbania rostrata stem nodules. During stem nodule development, most of the nodule-stimulated genes are expressed concomitantly with leghemoglobin at day 12 after inoculation. However, some genes are already stimulated at days 6–7, some others later in development (day 18), and some are transiently activated. Patterns of root nodules induced by either Azorhizobium caulinodans strain ORS571, capable of effective root and stem nodulation, or Rhizobium sp. strain ORS51, capable of effective root nodulation only, are very similar except for a specific 37.5 kDa polypeptide. Several types of ineffective stem and root nodules were studied; in every case the amount of leghemoglobin components appeared reduced together with most of the nodule-stimulated polypeptides.     

Rates of development of Hydrotaea rostrata under summer and winter (cyclic and constant) temperature regimes

The black carrion fly Hydrotaea rostrata Robineau-Desvoidy (Diptera: Muscidae) is a muscid, which occurs on approximately one-third of decomposing human corpses involved in homicide cases in south-western Australia. Work to date on its development rates is scant with only one published source available. The current study measured the precise developmental rates of this species using high repetition and sampling rates. A comparison was made of the developmental rates between constant and cyclic temperatures in winter and summer temperature regimes in south-western Australia. Developmental times for 90% of first stage larvae to emerge as adult flies are: summer constant, 21.6days, summer cyclic, 23.5 days, winter constant 64.5days and winter cyclic, 48.3 days. These data will allow forensic entomologists to make more accurate determinations of post-mortem intervals in cases where H. rostrata life history stages are present.