Spawning seasons of Rasbora tawarensis (Pisces: Cyprinidae) in Lake Laut Tawar,Aceh Province,Indonesia

Background  

Rasbora tawarensis is an endemic freshwater fish in Lake Laut Tawar, Aceh Province, Indonesia. Unfortunately, its status is regarded as critical endangered with populations decreasing in recent years. To date no information on the spawning activities of the fish are available. Therefore, this study provides a contribution to the knowledge on reproductive biology of R. tawarensis especially on spawning seasons as well as basic information for conservation of the species.     

Asp-376-Glu substitution endows target-site resistance to AHAS inhibitors in Limnocharis flava,an invasive weed in tropical rice fields

Limnocharis flava (L.) Buchenau is a problematic weed in rice fields and water canals of Southeast Asia, and in Malaysia this invasive aquatic weed species has evolved multiple resistance to synthetic auxin herbicide and acetohydroxyacid synthase (AHAS) inhibitors. In this study, it was revealed that, a single nucleotide polymorphism (SNP) at amino acid position 376, where C was substituted to G at the third base of the same codon (GAC to GAG), resulting in Aspartate (Asp) substitution by Glutamate (Glu) was the contributing resistance mechanism in the L. flava population to AHAS inhibitors. In vitro assay further proved that, all the L. flava individuals carrying AHAS resistance mutation exhibited decreased-sensitivity to AHAS inhibitors at the enzyme level. In the bensulfuron-methyl whole-plant bioassay, high resistance indices (RI) of 328- and 437-fold were recorded in the absence and presence of malathion (the P450 inhibitor), respectively. Similarly, translocation and absorption of bensulfuron-methyl in both resistant and susceptible L. flava populations showed no remarkable differences, hence eliminated the possible co-existence of non-target-site resistance mechanism in the resistant L. flava. This study has confirmed another new case of a target-site resistant weed species to AHAS-inhibitors.     

Syntheses, structures and vibrational spectroscopy of some 1:1 and 1:2 adducts of silver(I) oxyanion salts with 2,2′-bis(pyridine) chelates

Syntheses and room-temperature single-crystal X-ray structure determinations are recorded for a number of adducts of 1:1 stoichiometry of silver(I) oxyanion salts (perchlorate, nitrate, trifluoroacetate (‘tfa’) (increasing basicity)) with 2,2′-bis(pyridine) ligands (2,2′-bipyridyl, ‘bpy’; 2,2′-biquinolyl, ‘bq’; 2,2′-dipyridylketone, ‘dpk’; 2,9-dimethylphenanthroline, ‘dmp’). The adducts take two forms: (a) neutral mononuclear molecules, in which the 2,2′-bis(pyridine) ligand behaves as a chelate, with the silver coordination number dependent on the denticity of the anion; these are Agtfa:bpy (1:1) and AgClO₄:bq (1:1) (and various (ionic) acetonitrile or pyridine solvates AgClO₄:bq/dmp:MeCN/py (1:1:1), in which the solvent molecules are coordinated); and (b) one-dimensional polymers. The latter are diverse: in AgClO₄:bpy, dpk (1:1), the anion is discrete, the polymer made up of an array of two-coordinate silver atoms linked by bpy ligands twisted about their central connecting element. In AgNO₃:bpy, bq (1:1), the bpy ligands are chelating with the oxyanions bridging, cf. previously reported AgNO₃:dpk (1:1), in which the nitrate chelates the metal, with the dpk bridging, chelating N,O to one silver, while the other nitrogen bridges to the next. With Agtfa, a novel binuclear adduct has been isolated in conjunction with the hydrated ligand, Agtfa:dpk:(dpk · H₂O) (1:1:2). The far-IR spectra of several of these complexes show bands that can be assigned to the ν(AgN) modes, the positions of these bands correlating well with the relative Ag-N bond lengths.Syntheses and single-crystal X-ray structural characterizations are also reported for various adducts of silver(I) perchlorate, nitrate and trifluoromethanesulfonate with bpy, bq, ‘phen’ (= 1,10-phenanthroline), and ‘dmp’, of stoichiometry AgX:L (1:2). In each case the complex is ionic [AgL₂]X; the silver atom is four-coordinate, but diverse and remarkable variations in stereochemistries associated with changes in the interligand N-Ag-N angles, presumably influenced by the different packing arrangements, are observed.     

Phenological growth stage of tropical shallot (Allium cepa L. Aggregatum group) planted from seed in lowland area based on the BBCH scale

Shallot (Allium cepa L. Aggregatum group) is an important Allium plant commonly grown in tropical countries, including Indonesia, and it is used as spice for daily cooking, medicine, cosmetics and dietary supplements. Since shallot is predominantly propagated vegetatively by bulbs, it augments pathogen accumulation which influences low seed bulb management as well as productivity. Hence, utilisation of seeds/True Seed Shallot (TSS) emerges an alternative propagation material. However, no information is available on the growth stages of shallot plants from TSS. The phenological growth stages of tropical shallot planted in lowland areas using seeds in accordance with the Biologische Bundesanstalt, Bundessortenamt nd CHemische Industrie (BBCH) scale are first described here. Five introduced TSS cultivars, that is, Tuk Tuk, Lokananta, Sanren, Maserati, Tropix and four landraces TSS cultivars, that is, Bima, Biru Lancor, Pancasona and Trisula, were used as planting materials to develop an extended numerical BBCH scale for the identification of different phenological growth stages of shallot from seed. The study was conducted in lowland areas under tropical conditions of Indonesia. Based on BBCH scale, phenology of tropical shallot from seed in lowland area exhibited five of the 10 principal stages (0–9): germination (stage 0), leaf development (stage 1), formation of lateral shoot/tiller of pseudostem (stage 2), development of bulb (harvestable vegetative part) (stage 4), and senescence (stage 9). The codification of the different growth stages is essential in determination of the correct timing for better crop management, particularly for transplanting, fertilisation, control of weeds, disease and pest, plant growth regulators application and harvest time. As an implication, these BBCH scales could be used in plant breeding activities to shorten the TSS life cycle.     

Inhibitory evaluation of Curculigo latifolia on α-glucosidase,DPP (IV) and in vitro studies in antidiabetic with molecular docking relevance to type 2 diabetes mellitus

The inhibition of α-glucosidase and DPP enzymes capable of effectively reducing blood glucose level in the management of type 2 diabetes. The purpose of the present study is to evaluate the inhibitory potential of α-glucosidase and DPP (IV) activity including with the 2-NBDG uptake assay and insulin secretion activities through in vitro studies. The selected of active compounds obtained from the screening of compounds by LC-MS were docked with the targeted enzyme that involved in the mechanism of T2DM. From the results, root extracts displayed a better promising outcome in α-glucosidase (IC₅₀ 2.72 ± 0.32) as compared with the fruit extracts (IC₅₀ 3.87 ± 0.32). Besides, root extracts also displayed a better activity in the inhibition of DPP (IV), enhance insulin secretion and glucose uptake activity. Molecular docking results revealing that phlorizin binds strongly with α-glucosidase, DPP (IV) and Insulin receptor (IR) enzymes with achieving the lowest binding energy value. The present work suggests several of the compounds have the potential that contribute towards inhibiting α-glucosidase and DPP (IV) and thus effective in lowering post-prandial hyperglycaemia.     

Linocarpon angustatum sp. nov., andNeolinocarpon nypicola sp. nov. from petioles ofNypa fruticans, and a list of fungi from aerial parts of this host

Two new ascomycetes,Linocarpon angustatum sp. nov. andNeolinocarpon nypicola sp. nov., are described from petioles ofNypa fruticans in Malaysia.Linocarpon angustatum differs from species in the genus in having needle-shaped ascospores.Neolinocarpon nypicola differs from species in the genus in having filiform ascospores which gradually taper towards the ends, and ascomata developing within well developed stromata. These new species are compared with existing species and illustrated with interference light micrographs. The fungi known from aerial parts ofNypa fruticans are listed.