Isolation and screening of potential actinobacteria for rapid composting of rice straw

Rice straw is produced as a by-product from rice cultivation, which is composed largely of lignocellulosic materials amenable to general biodegradation. Lignocellulolytic actinobacteria can be used as a potential agent for rapid composting of bulky rice straw. Twenty-five actinobacteria isolates were isolated from various in situ and in vitro rice straw compost sources. Isolates A2, A4, A7, A9 and A24 were selected through enzymatic degradation of starch, cellulose and lignin followed by the screening for their adaptability on rice straw powder amended media. The best adapted isolate (A7) was identified as Micromonospora carbonacea. It was able to degrade cellulose, hemicelluloses and carbon significantly (P ≤ 0.05) over the control. C/N ratio was reduced to 18.1 from an initial value of 29.3 in 6 weeks of composting thus having the potential to be used in large scale composting of rice straw.     

Polygalacturonase activity and variation in ripening of papaya fruit with tissue depth and heat treatment

Effects of tissue position (viz. outer vs inner mesocarp) and heat treatment (48°C, 20 min) on variations in polygalacturonase (EC 3.2.1.15 and EC 3.2.1.67) activity and ripening of fruits of Carica papaya L. cv. Backcross Solo were investigated. Polygalacturonase activity increased during ripening concomitantly with an increase in tissue softness and soluble polyuronide level. Throughout ripening, inner mesocarp tissue was softer and contained higher polygalacturonase activity than outer mesocarp tissue. Titratable acidity as well as ß-galactosidase (EC 3.2.1.23) activity also increased during ripening; however, unlike polygalacturonase, their level or activity was lower in inner than in outer mesocarp. Ascorbic acid could partially account for the increase in titratable acidity during ripening but contributed very little to the differences in titratable acid levels between outer and inner mesocarp. Heat treatment had no effect on either fruit softness or titratable acidity, but it markedly reduced the increase in ascorbic acid and polygalacturonase activity during ripening. Ripening, as reflected by changes in tissue softness and polygalacturonase activity, progressed outwardly from the interior towards the exterior of the fruit. The effect of heat treatment in suppressing polygalacturonase activity was relatively greater in inner than in outer mesocarp, suggesting that sensitivity of the enzyme to heat treatment may vary with stage of ripeness of the tissue.     

Isolation and regional localization of a large collection (2,000) of single-copy DNA fragments on human chromosome 3 for mapping and cloning tumor suppressor genes

Summary A collection of 2,000 lambda phage-carrying human single-copy inserts (> 700 bp) were isolated from two chromosome-3 flow-sorted libraries. The single-copy DNA fragments were first sorted into 3p and 3q locations and about 700 3p fragments were regionally mapped using a deletion mapping panel comprised of two humanhamster and two-human-mouse cell hybrids, each containing a chromosome 3 with different deletions in the short arm. The hybrids were extensively mapped with a set of standard 3p markers physically localized or ordered by linkage. The deletion mapping panel divided the short arm into five distinct subregions (A-E). The 3p fragments were distributed on 3p regions as follows: region A, 26%; B, 31%; C, 4%; D, 4% and E, 35%. We screened 300 single-copy DNA fragments from the distal part of 3p (regions A and B) with ten restriction endonucleases for their ability to detect restriction fragment length polymorphisms (RFLPs). Of these fragments 110 (36%) were found to detect useful RFLPs: 35% detected polymorphisms with frequency of heterozygosity of 40% or higher, and 25% with frequency of 30% or higher. All polymorphisms originated from single loci and most of them were of the base pair substitution type. These RFLP markers make it possible to construct a fine linkage map that will span the distal part of chromosome 3p and encompasses the von Hippel-Lindau disease locus. The large number of single-copy fragments (2,000) spaced every 100–150 kb on chromosome 3 will make a significant contribution to mapping and sequencing the entire chromosome 3. The 300 conserved chromosome 3 probes will increase the existing knowledge of man-mouse homologies.     

Oil palm (Elaeis guineensis) protoplasts: isolation, culture and microcallus formation

Procedures are deseribed for the efficient isolation of protoplasts from a variety of oil palm (Elaeis guineensis Jacq.) tissues. Various factors including donor source, composition of enzyme mixture and culture medium affected the yield and viability of the protoplasts Polyembryogenic cultures of oil palm were the most suitable starting material in terms of yield, viability and metabolic competence. Pectolyase Y-23 in association with cellulase and hemicellulase was required for the efficient release of protoplasts from the oil palm tissues. Limited cell division to form microcallus was observed at very low frequency (<0.01%) when glutathione and catalase were incorporated in the culture medium.Abbreviations 2,4-d dichlorophenoxyacetic acid - DTT dithiothreitol - MES 2[N-morpholino] ethanesulphonic acid - NAA 1-naphthalene acetic acid - PVP polyvinylpyrrolidone     

Regulation of N-Methyl-d-aspartate receptor-mediated calcium transport and norepinephrine release in rat hippocampus synaptosomes by polyamines

The role of polyamines (PA) synthesis in NMDA receptor-mediated⁴⁵Ca²⁺ fluxes and norepinephrine release was studied in rat hippocampal synaptosomes. NMDA (50M) caused a sharp (>2-fold) transient increase in PA synthesis regulating enzyme, ornithine decarboxylase (ODC) activity with concomitant elevation in PA levels in the order putrescine>spermidine>spermine. ODC inhibitor, -difluoromethylornithine (DFMO), and NMDA antagonist, 2-amino-5-phosphonovaleric acid (D-AP5), both blocked increases in ODC activity and PA levels. Activation of NMDA receptors induced a sharp (3 to 4-fold) and quick (15 seconds) increase in⁴⁵Ca²⁺ uptake by synaptosomes within 15 seconds of exposure at 37°C. The efflux of⁴⁵Ca²⁺ and³H-norepinephrine (NE) release at 22°C from pre-loaded synaptosomes was also significantly (2 to 4-fold) enhanced by NMDA within 15 seconds. These NMDA receptor-mediated effects on calcium fluxes and NE release were blocked by NMDA receptor-antagonists (DAP-5 and MK-801) and PA synthesis inhibitor, DFMO and the DFMO inhibition nullified by exogenous putrescine. These observations establish that ODC/PA cascade play an important role in transduction of excitatory amino acid mediated signals at NMDA receptors.Special issue dedicated to Dr. Sidney Ochs.     

The isochore patterns of mammalian genomes and their phylogenetic implications

The compositional distributions of high molecular weight DNA fragments from 20 species belonging to 9 out of the 17 eutherian orders were investigated by analytical CsCl density gradient centrifugation and by preparative fractionation in Cs₂SO₄/BAMD density gradients followed by analysis of the fractions in CsCl. These compositional distributions reflect those of the isochores making up the corresponding genomes. A “general distribution” was found in species belonging to eight mammalian orders. A “myomorph distribution” was found in Myomorpha, but not in the other rodent infraorders Sciuromorpha and Histricomorpha, which share the general distribution. Two other distributions were found in a megachiropteran (but not in microchiropteran, which, again, shares the general distribution) and in pangolin (a species from the only genus of the order Pholidota), respectively. The main difference between the general distribution and all other distributions is that the former contains sizable amounts (6–10%) of GC-rich isochores (detected as DNA fragments equal to, or higher than, 1.710 g/cm³ in modal buoyant density), which are scarce, or absent, in the other distributions. This difference is remarkable because gene concentrations in mammalian genomes are paralleled by GC levels, the highest gene concentrations being present in the GC-richest isochores. The compositional distributions of mammalian genomes reported here shed light on mammalian phylogeny. Indeed, all orders investigated, with the exception of Pholidota, seem to share a common ancestor. The compositional patterns of the megachiropteran and of Myomorpha may be derived from the general pattern or have independent origins.     

Nanostructured material-based optical and electrochemical detection of amoxicillin antibiotic

The penicillin derivative amoxicillin (AMX) plays an important role in treating various types of infections caused by bacteria. However, excessive use of AMX may have negative health effects. Therefore, it is of utmost importance to detect and quantify the AMX in pharmaceutical drugs, biological fluids, and environmental samples with high sensitivity. Therefore, this review article provides valuable and up-to-date information on nanostructured material-based optical and electrochemical sensors to detect AMX in various biological and chemical samples. The role of using different nanostructured materials on the performance of important optical sensors such as colorimetric sensors, fluorescence sensors, surface-enhanced Raman scattering sensors, chemiluminescence/electroluminescence sensors, optical immunosensors, optical fibre-based sensors, and several important electrochemical sensors based on different electrode types have been discussed. Moreover, nanocomposites, polymer, and MXenes-based electrochemical sensors have also been discussed, in which such materials are being used to further enhance the sensitivity of these sensors. Furthermore, nanocomposite-based photo-electrochemical sensors and the market availability of biosensors including AMX have also been discussed briefly. Finally, the conclusion, challenges, and future perspectives of the above-mentioned sensing techniques for AMX detection are presented.     

Anopheles culicifacies: The occurrence of multiple insemination under laboratory conditions

Multiple insemination was detected under laboratory conditions in 38 of 399 females of Anopheles culicifacies Giles using a sex-linked, recessive eye-color marker system. Multiple mating occurred less frequently at low pair density and was not detected in a large cage. Remating after a 24-hr delay was detected in 5 of 131 families. The high incidence of multiple mating was attributed to interrupted copulations resulting in the transference of inadequate quantities of male accessory gland substance and/or by remating before insemination barriers were established after the initial insemination.

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Anopheles culicifacies giles: La presence d'inseminations multiples dans les conditions de laboratoire

Résumé Les inséminations multiples ont été mises en évidence dans les conditions de laboratoire chez 38 sur 399 femelles d'Anopheles culicifacies en utilisant un marqueur récessif colorant l'il, lié au sexe. Les copulations répétées sont moins fréquentes aux faibles densités et n'ont pas été observées dans de grandes cages. La recopulation après un délai de 24 h a été observée dans 5 familles sur 131. La haute fréquence de copulations multiples est envisagée comme conséquence de copulations interrompues, empéchant le transfert de quantités adéquates de sécrétions des glandes accessoires mâles et/ou par la recopulation avant que les barrières de non réceptivité aient été établies par l'insémination initiale.

     

Anopheles subpictus Grassi: Observations on survivorship and population size using mark-release-recapture and dissection methods

A mark-release-recapture experiment to estimate population survivorship and absolute size was performed with wild-caught An. subpictus adults at the village of Khano-Harni, Lahore District, Punjab Province, Pakistan during September 1978, the end of the monsoon rainy season, when temporal population abundance was maximized. Daily survival rate estimated from the recapture sequence of marked adults was low, males=0.192 and females=0.343. Survivorship for females estimated by several vertical age-grading procedures ranged from 0.347 to 0.628. Both stage- and age-specific life tables were calculated from vertical age-grading data determined by the dilatation method. Female and male population size was estimated byBailey 's modification of theLincoln Index and was found to average 4478.4 and 6106.8, respectively. The bionomics, survivorship and population size of An. subpictus in the Lahore are indicated that this species was probably not important in the transmission of human malaria.