Protein degradation in aged nematodes (Turbatrix aceti).

The rates of degradation of total soluble proteins in the free-living nematode, $\text{Turbatrix aceti}$, have been estimated by following the loss of acid-insoluble insoluble radioactivity from protein during a nonradioactive chase period after initial labeling with [³⁵S]methionine. These proteins appear to lose label kinetically as a homogeneous class in age-synchronized nematode populations. However, proteins are degraded more slowly in senescent cultures than in young cultures. Protein degradation rates decline progressively during nematode aging. These findings suggest that the protein degradative system in T. aceti may become partially defective with advancing age which may result in the accumulation of aberrant protein molecules in senescent organisms.     

Synthesis of novel nitric oxide (NO)-releasing esters of timolol

A novel class of timolol derivatives with nitric oxide (NO)-donating moieties achieved chemical stability yet under physiologically relevant conditions released timolol and NO. Hindered esters A were designed and synthesized, whose ‘triggered’ release relied on enzymatic hydrolysis of the nitrate ester in A to B, that in turn cyclized to liberate timolol.     

Endophytic bacterial flora in the stem tissue of a tropical maize (<Emphasis Type="Italic">Zea mays</Emphasis> L.) genotype: isolation,identification and enumeration

The genotypic diversity of indigenous bacterial endophytes within stem of tropical maize (Zea mays L.) was determined in field and greenhouse experiments. Strains were isolated from stem tissues of a tropical maize cultivar (PEHM-1) by trituration and surface disinfestation and their population dynamics was determined. Endophytes were found in most of the growing season at populations ranging from 1.36–6.12 × 10⁵ colony-forming units per gram fresh weight (c.f.u./gm fw) of stem. Analysis of these bacterial endophytes using Gas Chromatography—Fatty Acid Methyl Ester (GC-FAME) led to the identification of Bacillus pumilus, B. subtilis, Pseudomonas aeruginosa and P. fluorescens as the relatively more predominant group of bacterial species residing in maize stem. When the maize seedlings grown in a greenhouse were inoculated with these four isolates individually, their population densities decreased (1.6–3.1 × 10⁵ c.f.u./gm fw of stem) as compared to the field-grown maize (1.8–3.8 × 10⁵ c.f.u./gm fw of stem). The highest persistence, however, was recovered in the case of B. subtilis with a population density of 3.1 × 10⁵ c.f.u./gm fw of stem tissue on 28 days after emergence (DAE). This is the first report on population dynamics of bacterial endophytes from tropical maize and the results establish that symptomless populations of bacteria exist in the maize stem.     

Learning-related synaptic plasticity: LTP and LTD.

The past several years have seen studies of synaptic plasticity in both invertebrate and vertebrate nervous systems come of age and lead to important new findings. In particular, current evidence points to a possible presynaptic site for long-term potentiation and the involvement of a retrograde messenger from the postsynaptic neuron. Recent advances in both cerebellar and cortical forms of long-term depression are also discussed.     

Interfacial Effects of Tin Oxide Atomic Layer Deposition in Metal Halide Perovskite Photovoltaics

Metal halide perovskites offer a wide and tunable bandgap, making them promising candidates for top‐cell absorbers in tandem photovoltaics. In this work, the authors aim to understand the atomic layer deposition (ALD) precursor–perovskite interactions of the tin oxide ALD system and the role of organic fullerenes at the perovskite–tin oxide interface while establishing a framework for developing alternative perovskite‐compatible ALD processes in the future. It is shown, in the case of tin oxide ALD growth with tetrakis(dimethylamino)tin(IV) and water on FA_0.83Cs_0.17Pb(I_0.83Br_0.17)₃ perovskite, that perovskite stability is most sensitive to metal–organic exposure at elevated temperatures with an onset near 110 °C, resulting in removal of the formamidinium cation. Transitioning from ALD to pulsed‐chemical vapor deposition tin oxide growth can minimize the degradation effects. Investigation of fullerenes at the perovskite interface shows that thin fullerene layers offer minor improvements to perovskite stability under ALD conditions, but significant enhancement in carrier extraction. Fullerene materials are undesirable due to fabrication cost and poor mechanical stability. Compositional tuning of the perovskite material can improve the fullerene‐free device performance. This method is demonstrated with a bromine‐rich perovskite phase to enable an 8.2% efficient perovskite device with all‐inorganic extraction layers.     

Cannabinoid Modulation of Eukaryotic Initiation Factors (eIF2α and eIF2B1) and Behavioral Cross-Sensitization to Cocaine in Adolescent Rats

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Structural analysis of protein tyrosine phosphatase 1B reveals potentially druggable allosteric binding sites

Catalytic proteins such as human protein tyrosine phosphatase 1B (PTP1B), with conserved and highly polar active sites, warrant the discovery of druggable nonactive sites, such as allosteric sites, and potentially, therapeutic small molecules that can bind to these sites. Catalyzing the dephosphorylation of numerous substrates, PTP1B is physiologically important in intracellular signal transduction pathways in diverse cell types and tissues. Aberrant PTP1B is associated with obesity, diabetes, cancers, and neurodegenerative disorders. Utilizing clustering methods (based on root mean square deviation, principal component analysis, nonnegative matrix factorization, and independent component analysis), we have examined multiple PTP1B structures. Using the resulting representative structures in different conformational states, we determined consensus clustroids and used them to identify both known and novel binding sites, some of which are potentially allosteric. We report several lead compounds that could potentially bind to the novel PTP1B binding sites and can be further optimized. Considering the possibility for drug repurposing, we discovered homologous binding sites in other proteins, with ligands that could potentially bind to the novel PTP1B binding sites.     

In vitro culture provides additional variation for pigeonpea

Summary The present study is an attempt to exploit somaclonal variation for the varietal improvement of pigeonpea [Cajanus cajan (L) Millsp.]. The pigeonpea plants were regenerated from cotyledon explants, and their progeny was screened for variability. The regenerated R1 plants exhibited a spectrum of alterations in floral morphology and architecture that were absent in the control population. The field-sown R2 plants segregated for traits such as flower color, leaf shape, seed size, color and strophiolation, flowering habit, and fertility. Tissue culture produced different mutational events resulting in both dominant and recessive alleles. Significant variation was observed for plant height, seed mass, and damage due to the insect pest Helicoverpa armigera. The R3 plants, obtained from seed of R2 generation selected for traits such as white seed coat, strophiolation, reduced plant height, seed mass and low damage due to Helicoverpa, maintained the traits when compared with the seed-derived control populations. The results indicate a definite gene for white seed coat and the possibility of additional genes for pest tolerance and high seed mass in an adapted background. Submitted as Journal Article No. 1906 by International Crops Research Institute for the Semi-Arid Tropics (ICRISAT).