Lesions of the Basal Forebrain Cholinergic System in Mice Disrupt Idiothetic Navigation

Loss of integrity of the basal forebrain cholinergic neurons is a consistent feature of Alzheimer’s disease, and measurement of basal forebrain degeneration by magnetic resonance imaging is emerging as a sensitive diagnostic marker for prodromal disease. It is also known that Alzheimer’s disease patients perform poorly on both real space and computerized cued (allothetic) or uncued (idiothetic) recall navigation tasks. Although the hippocampus is required for allothetic navigation, lesions of this region only mildly affect idiothetic navigation. Here we tested the hypothesis that the cholinergic medial septo-hippocampal circuit is important for idiothetic navigation. Basal forebrain cholinergic neurons were selectively lesioned in mice using the toxin saporin conjugated to a basal forebrain cholinergic neuronal marker, the p75 neurotrophin receptor. Control animals were able to learn and remember spatial information when tested on a modified version of the passive place avoidance test where all extramaze cues were removed, and animals had to rely on idiothetic signals. However, the exploratory behaviour of mice with cholinergic basal forebrain lesions was highly disorganized during this test. By contrast, the lesioned animals performed no differently from controls in tasks involving contextual fear conditioning and spatial working memory (Y maze), and displayed no deficits in potentially confounding behaviours such as motor performance, anxiety, or disturbed sleep/wake cycles. These data suggest that the basal forebrain cholinergic system plays a specific role in idiothetic navigation, a modality that is impaired early in Alzheimer’s disease.     

Plant contents and quality of makhana (Euryale ferox)

Summary As a part of integrated study of makhana, the mineral contents of the plant parts and the fruits of makhana (Euryale ferox) have been presented here. It has been observed that the fruits were not only rich in minerals but also in protein. The plant parts also contained high amounts of micronutrients. Its fruits are, therefore, a good supplement for minerals which are produced from otherwise agriculturally waste (water-logged) areas.     

In vitro regeneration of Ruscus hypophyllum L. plants

Callus cultures were established from stem explants of Ruscus hypophyllum on a modified basal medium of Murashige and Skoog (1962) supplemented with 1 mg l^-1 2,4-D+0.1 mg l^-1 BAP. The optimal 2,4-D concentration for promoting shoot bud formation and growth was 0.05 mg l^-1 along with 0.5 mg l^-1 BAP. Sixty percent of rootless shoots produced flowers on the regenerating medium. Rooting was induced when shoots were transferred to half strength MS inorganic salts supplemented with 2 mg l^-1 IBA. Eighty percent of plants transferred to soil have survived.     

The effect of 2-deoxy-D-glucose on insulin release by neonatal rat B cells in culture

The culture for 7 days in medium with 5.5 mM glucose and 1 mM 2-deoxy-D-glucose enhanced the glucose sensitivity of neonatal rat B cells, and even stimulated their growth in vitro. Also, 2-deoxy-D-glucose supplementation maintained insulin release evoked by leucine and 2-ketoisocaproate from B cells at day 7 at levels several times higher than at day 1. The effect of leucine was greatly augmented by glutamine, whereas that of the 2-keto acid remained almost unchanged irrespective of the presence of glutamine. These results suggest an increase in oxidative catabolism of medium nutrients in B cells grown in medium with 2-deoxy-D-glucose for 7 days, and such metabolic changes may promote the growth of B cells in vitro.     

Litter and soil biodiversity jointly drive ecosystem functions

The decomposition of litter and the supply of nutrients into and from the soil are two fundamental processes through which the above- and belowground world interact. Microbial biodiversity, and especially that of decomposers, plays a key role in these processes by helping litter decomposition. Yet the relative contribution of litter diversity and soil biodiversity in supporting multiple ecosystem services remains virtually unknown. Here we conducted a mesocosm experiment where leaf litter and soil biodiversity were manipulated to investigate their influence on plant productivity, litter decomposition, soil respiration, and enzymatic activity in the littersphere. We showed that both leaf litter diversity and soil microbial diversity (richness and community composition) independently contributed to explain multiple ecosystem functions. Fungal saprobes community composition was especially important for supporting ecosystem multifunctionality (EMF), plant production, litter decomposition, and activity of soil phosphatase when compared with bacteria or other fungal functional groups and litter species richness. Moreover, leaf litter diversity and soil microbial diversity exerted previously undescribed and significantly interactive effects on EMF and multiple individual ecosystem functions, such as litter decomposition and plant production. Together, our work provides experimental evidence supporting the independent and interactive roles of litter and belowground soil biodiversity to maintain ecosystem functions and multiple services.     

Antioxidant and Antidiabetic Properties of Extracts from Three Underutilized Food Plants of North East India

Three underutilized leafy vegetables Sarcochlamys pulcherrima (Roxb.) Gaudich (SP), Ipomoea aquatica Forssk. (IA) and Zanthoxylum rhetsa (Roxb.) DC (ZR) were extracted with different solvents viz. 95 % ethyl alcohol, methanol and hot water. The extracts were evaluated for their antioxidant potential via DPPH, ABTS and FRAP assay along with electroanalytical studies using cyclic voltammetry. The antidiabetic potential was determined by recording their α-amylase and α-glucosidase inhibitory assay. The total phenolic content (TPC), total flavonoid content (TFC) and the liquid chromatography-mass spectrometry (LC/MS) based phytochemical profiles of the extracts were also determined. All three extracts of SP exhibited significant antioxidant capacity. The antidiabetic potential of the IA and ZR extracts was found to be higher than or at par with that of standard acarbose. LC/MS studies reveal the presence of hitherto reported antioxidant and antidiabetic compounds like gamma-aminobutyric acid, cinnamic acid, caffeic acid, α-viniferin, piperlonguminine, niacin, kaempferol, etc., in the extracts.     

Normal rat kidney proximal tubule cells in primary and multiple subcultures

Summary Anin vitro model to establish primary and subcultures of rat kidney proximal tubule (RPT) cells is described. After excising the kidneys and separating the cortex, the cortical tissue is digested with the enzyme DNAse-collagenase (Type I) resulting in a high yield of viable RPT Cells. The isolated RPT cells are then seeded onto rat tail collagen-coated surfaces and grown to confluency in a serum-free, hormonally defined medium. The cell yield can be increased by transfering the conditioned medium on Day 1 to more rat tail collagen-coated surfaces. RPT cell attachment and morphology was better on rat tail collagen-coated surfaces than on bovine collagen Type I coated surfaces. The culture medium was a 1∶1 mixture of Ham’s F-12 and Dulbecco’s modified Eagle’s medium supplemented with bovine serum albumin, insulin, transferrin, selenium, hydrocortisone, triiodothyronine, epidermal growth factor, and glutamine. The RPT cells became confluent in 7–10 d, at which point they could be subcultured by trypsinizing and growth in the same medium. In some studies, 10 ng/ml cholera toxin was added to the culture medium. We could passage the RPT cells up to 14 times in the presence of cholera toxin. The cells were investigated for activity of several markers. The cells were histochemically positive for alkaline phosphatase and γ-glutamyl transpeptidase activity and synthesized the intermediate filament pankeratin. The RPT cells displayed apically directed sodium-dependent active glucose transport in culture. Hence, the RPT cells retain structural and functional characteristics of transporting renal epithelia in culture. This rat cell culture model will be a valuable tool for substrate uptake and nephrotoxicity studies.     

Interaction of lentil lectin with human platelets. Evidence against glycoprotein II as aggregation mediator

Human platelets bind on an average of 5 × 10⁵ molecules of lentil lectin/cell with an apparent dissociation constant of 3 × 10^?7 M. The lectin binds mainly to surface glycoprotein II with an apparent molecular weight of 125,000. Lentil lectin neither caused aggregation nor did it inhibit platelet aggregation by other agents. It had no influence on the binding of thrombin to platelets or on thrombin-induced clot retraction. The hypothesis that glycoprotein II mediates platelet aggregation needs reevaluation.     

Rhizogenesis fromNigella sativa protoplasts

Summary Protoplasts were isolated for the first time from cell suspensions ofNigella sativa. These were then cultured in media and observed at regular intervals. Different concentrations of auxin and kinetin were tried with success to obtain root from the callus tissues of the protoplasts.     

Spoil characteristics and vegetation development of an age series of mine spoils in a dry tropical environment

A series of coal mine spoils (5, 10, 12, 16 and 20-yr old) in a dry tropical environment was sampled to assess the changes with time in spoil characteristics, species composition and plant biomass. Coarse fragments (>2 mm) decreased with age of mine spoil while the proportion of 0.2–0.1 mm particles increased. Total soil N, mineral N, NaHCO₃-extractable Pi, and exchangeable K increased with age of mine spoil and these parameters were lower in mine spoils than native forest soil even after 20 years of succession. Exchangeable Na decreased with age of mine spoil and in 20-yr old spoil it was higher than native forest soil. Plant community composition changed with age. Only a few species participated in community formation. Species richness increased with age, while evenness and species diversity declined from 5-yr old to 16-yr old community with an increase in the 20-yr old community. A reverse trend occurred for concentration of dominance. Area-weighted shoot and root biomass of other species increased with the age of the mine spoil while that of Xanthium strumarium patches declined with age. Data collected on spoil features, microbial C, N and P, and shoot and root biomass when subjected to Discriminant Analysis indicated a continued profound effect of age. 10 and 12-yr old mine spoils were closer to each other, and 5 and 20-yr old spoils were farthest apart.