Hypoglycemic and antihyperglycemic effect of Brassica juncea diet and their effect on hepatic glycogen content and the key enzymes of carbohydrate metabolism

Plants in the form of food or other remedial forms have been used for the treatment of various human ailments. Diabetes is one such disorder in which various form of plants and herbal remedies have been tried. Brassica juncea (BJ) seeds (Rai) are consumed in India as a spice in various food items. Previous studies have shown the hypoglycemic effect of this plant in rats. The present study was undertaken to study the hypoglycemic and anti-hyperglycemic of various strengths (5, 10 and 15%) of BJ seed diet in alloxan and streptozotocin induced diabetes in albino rats. In addition, key enzymes of carbohydrate metabolism (glucokinase – EC 2.7.1.1, hexokinase – EC 2.7.1.1, and phosphofructokinase – EC 2.7.1.11) and hepatic glycogen content was also assessed to understand the mechanism of action. BJ diet (10 and 15%) showed significant anti-hyperglycemic effect in alloxan (35 mg/kg) but not in STZ (60 mg/kg) rats. It also failed to modulate the hepatic glycogen content and enzyme activities.     

Experimental study on the origin of pancreatic endocrine cells in the toad Bufo bufo L.

Summary Ablation, transplantation and culture experiments were used to determine the respective roles of the pancreatic dorsal and ventral anlagen in the formation of the endocrine cells. Three successive waves of endocrine formation occur in the pancreas of Bufo bufo at three developmental stages (III₆, IV₁ and IV₂). Each wave is derived from a different source: the first originates from the dorsal anlage, the second from the exocrine tissue of the cortex of the pancreas and the third from the pancreatic duct. Each generation of islets has a specific composition of different cell types. The first wave is only composed of insulin islets; the second wave gives rise to single insulin, glucagon and somatostatin cells; while the third wave generates single cells synthesizing one of the three hormones, homogeneous islets of insulin cells, rare glucagon islets and heterogeneous islets containing insulin cells in the centre and a few glucagon or somatostatin cells at the periphery.     

Response of the blood glucose and the pancreatic islets of the lizard, Uromastix hardwicki (Gray) to exogenous insulin.

Uromastix hardwicki was found more resistant to insulin as compared to other poikilotherms and this insulin resistance appears to be related to the preponderance of glucagon secreting alpha-cells in this species. The magnitude and the persistence of hypolgycemia caused by insulin are directly dependent upon the quantity of the dose. The higher doses (2000 and 3000 U/kg) resulted into shocks, but the lack of correlation between hypoglycemia and shocks has been attributed to the direct effect of insulin on the nervous system. Histologically, insulin induced degranulation of both the beta- and alpha-cells. The physiological action of insulin is apparently greater at higher ambient temperature. The ability of insulin to damage beta- and alpha-cells in Uromastix hardwicki further gathers evidence for the similarity of these cell types with those of mammals and other vertebrates in being the source of insulin and glucagon respectively, and in controlling the blood glucose homeostasis in this lizard.     

Role of voltage-dependent ionic currents in coupling glucose stimulation to insulin secretion in canine pancreatic islet B-Cells

Summary Glucose-induced electrical activity in canine pancreatic islet B cells is distinct from that in rodent islets, though both display Ca²⁺-dependent insulin secretion. Rodent islet B cells undergo regular bursts of Ca²⁺-dependent action potentials, while canine islet B cells generate isolated Na⁺-dependent action potentials which often give way to a plateau depolarization. Here we present evidence to reconcile the species difference in electrical activity with the similarity of Ca²⁺ dependence of secretion. (i) In canine B cells increasing glucose concentrations produce membrane depolarization and increasing frequency of Na_o-dependent action potentials until a background membrane potential (-40mV) is reached where Na⁺ currents are inactivated. (ii) Voltage-dependent Ca²⁺ currents are present which are activated over the voltage excursion of the action potential (–50 to +20 mV) and inactivate slowly, (over seconds) in the range of the plateau depolarization (–40 to –25 mV). Hence, they are available to contribute to both phases of depolarization. (iii) Tetrodotoxin (TTX) reduces by half an early transient phase of glucosestimulated insulin secretion but not a subsequent prolonged plateau phase. The transient phase of secretion often corresponds well in time to the period of initial high frequency action potential activity. These latter results suggest that in canine B cells voltagedependent Na⁺ and Ca²⁺ currents mediate biphasic glucose-induced insulin secretion. The early train of Na⁺-dependent action potentials, by transiently activating Ca²⁺ channels and allowing pulsatile Ca²⁺ entry, may promote an early transient phase of insulin secretion. The subsequent sustained plateau depolarization, by allowing sustained Ca²⁺ entry, may permit steady insulin release.     

Method for isolation of pancreatic blood vessels,their culture and coculture with islets of langerhans

The only cure available for Type 1 diabetes involves the transplantation of islets of Langerhans isolated from donor organs. However, success rates are relatively low. Disconnection from vasculature upon isolation and insufficient rate of revascularization upon transplantation are thought to be a major cause, as islet survival and function depend on extensive vascularization. Research has thus turned toward the development of pretransplantation culture techniques to enhance revascularization of islets, so far with limited success. With the aim to develop a technique to enhance islet revascularization, this work proposes a method to isolate and culture pancreas-derived blood vessels. Using a mild multistep digestion method, pancreatic blood vessels were retrieved from whole murine pancreata and cultured in collagen Type 1. After 8 days, 50% of tissue explants had formed anastomosed microvessels which extended up to 300 μm from the explant tissue and expressed endothelial cell marker CD31 but not ductal marker CK19. Cocultures with islets of Langerhans revealed survival of both tissues and insulin expression by islets up to 8 days post-embedding. Microvessels were frequently found to encapsulate islets, however no islet penetration could be detected. This study reports for the first time the isolation and culture of pancreatic blood vessels. The methods and results presented in this work provide a novel explant culture model for angiogenesis and tissue engineering research with relevance to islet biology. It opens the door for in vivo validation of the potential of these pancreatic blood vessel explants to improve islet transplantation therapies. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 35: e2745, 2019.     

Adventitious shoot formation in cultures of 30-year-old Larix decidua,L. leptolepis,L. eurolepis,and L. laricina trees

Primordial shoot explants excised from buds of one Larix decidua tree, about 30 years old, produced more adventitious buds, elongating into shoots, when grown on half strength Litvay medium than when grown on other basal media. Thidiazuron and N₆-benzyladenine (BA) were equally effective in adventitious bud induction. In a comparative study of 30-year-old L. decidua, L. leptolepis, L. eurolepis, and L. laricina trees, explants from L. eurolepis and L. decidua produced a high number of cultures with adventitious buds that elongated into shoots; those from L. leptolepis were less productive, and those from L. laricina failed to form adventitious buds. The highest response was obtained with material collected in August and September, and in March and April; the lowest response occurred in explants from the October collection.     

Inhibition of chilling-induced photooxidative damage to leaves of Cucumis sativus L. by treatment with amino alcohols

The effect of pretreatment of cucumber (Cucumis sativus L.) roots with choline chloride or ethanolamine on leaf phospholipid composition and light-induced leaf damage during chilling was studied. Photooxidative chlorophyll degradation was similarly inhibited by both amino alcohols. The decrease of the chlorophyll a/chlorophyll b ratio and the increase of polyunsaturated-fatty-acid degradation during chilling in the light were equally inhibited by pretreatment with choline chloride or ethanolamine. Treatment with choline chloride and ethanolamine caused, respectively, 43% and 26% increases in the total phospholipid contents of the leaves. After treatment with choline chloride, the phosphatidylcholine content was higher than the content of phosphatidylethanolamine; the reverse was true after treatment with ethanolamine. The chlorophyll concentration increased less than the phospholipid concentration, resulting in a decreased chlorophyll/phospholipid ratio of treated leaves. During chilling in the light, degradation of phosphatidylcholine, ethanolamine and phosphatidyl glycerol occurred. Phosphatidyl glycerol was less sensitive than phosphatidylcholine and ethanolamine. The degradation was equally inhibited by pretreatment with either amino alcohol. Possible connections between the phospholipid content of leaf membranes and the inhibition of chilling-induced photooxidative leaf damage are discussed.Abbreviations CC choline chloride - Chl chlorophyll - EA ethanolamine - PC phosphatidyl choline - PE phosphatidyl ethanolamine - PG phosphatidyl glycerol     

Response of Pinus sylvestris L. to recent climatic events in the French Mediterranean region

Exceptional climatic events from 2003 to 2005 (scorching heat and drought) affected the whole of the vegetation in the French Mediterranean region and in particular the Scots pine (Pinus sylvestris L.), one of the most important forest tree species in this area. To understand its response to these extreme conditions, we investigated its radial growth, branch length growth, architectural development and reproduction for the period 1995–2005, and linked these variables to climatic parameters. We used four plots situated in southeastern France and presenting different levels of site quality and potential forest productivity. The results show that: (1) the climatic episode 2003–2005 was highly detrimental to the growth (bole and branches), crown development, and cone production but favored the production of male flowers; (2) these variables depend on climatic factors of both the current and previous years; (3) the 2003 scorching heat impact was strong but was mainly apparent from 2004; it was part of a 6-year-long unfavorable cycle beginning in 2000, characterized by high minimum and maximum temperatures and very dry springs; (4) in spite of a significant effect of site quality, the Scots pine’s response to extreme climatic conditions was homogeneous in the French Mediterranean area; and (5) the stress induced by poor site conditions generally resulted in the same consequences for tree growth, architecture, and reproduction as in unfavorable climatic conditions.     

Effects of anisotonicity on pentose-phosphate pathway,oxidized glutathione release and t-butylhydroperoxide-induced oxidative stress in the perfused liver of air-breathing catfish,<Emphasis Type="Italic">Clarias batrachus</Emphasis>

Both hypotonic exposure (185 mOsmol/l) and infusion of glutamine plus glycine (2 mmol/l each) along with the isotonic medium caused a significant increase of¹⁴CO₂ production from [1-¹⁴C]glucose by 110 and 70%, respectively, from the basal level of 18.4 ± 1.2 nmol/g liver/min from the perfused liver ofClarias batrachus. Conversely, hypertonic exposure (345 mOsmol/l) caused significant decrease of¹⁴CO₂ production from [1-¹⁴C]glucose by 34%.¹⁴CO₂ production from [6-¹⁴C]glucose was largely unaffected by anisotonicity. The steady-state release of oxidized glutathione (GSSG) into bile was 1.18 ±0.09 nmol/g liver/min, which was reduced significantly by 36% and 34%, respectively, during hypotonic exposure and amino acid-induced cell swelling, and increased by 34% during hypertonic exposure. The effects of anisotonicity on¹⁴CO₂ production from [1-¹⁴C]glucose and biliary GSSG release were also observed in the presence of t-butylhydroperoxide (50 (Amol/1). The oxidative stress-induced cell injury, caused due to infusion of t-butylhydroperoxide, was measured as the amount of lactate dehydrogenase (LDH) leakage into the effluent from the perfused liver; this was found to be affected by anisotonicity. Hypotonic exposure caused significant decrease of LDH release and hypertonic exposure caused significant increase of LDH release from the perfused liver. The data suggest that hypotonically-induced as well as amino acid-induced cell swelling stimulates flux through the pentose-phosphate pathway and decreases loss of GSSG under condition of mild oxidative stress; hypotonically swollen cells are less prone to hydroperoxide-induced LDH release than hypertonically shrunken cells, thus suggesting that cell swelling may exert beneficial effects during early stages of oxidative cell injury probably due to swelling-induced alterations in hepatic metabolism.     

Effects of N-dodecyloxymethylene-N-methylpiperidinium,N-dodecyloxymethylene-N-methylmorpholinium,and N,N-dimethylmorpholinium chlorides on seed germination and seedling growth in Papaver somniferum L.

N-dodecyloxymethylene-N-methylpiperidinium (DMMP) and N-dodecyloxy-methylene-N-methylmorpholinium chlorides (DMMM) inhibited seed germination and root growth in poppy, DMMP being more active than DMMM. Similar effects were not produced by N,N-dimethylmorpholinium chloride, a plant growth retardant. It is suggested that DMMP and DMMM act by interfering with cell permeability.     

Effect of water temperature on dietary protein requirement,growth and body composition of Asian catfish, Clarias batrachus fry

This study aimed to evaluate the protein requirement of Clarias batrachus fry, were estimated at two different water temperatures, 28 and 32 °C. The influence of dietary protein level and water temperature on body composition, weight gain, food and nutrient utilization were estimated. The Asian catfish, C. batrachus fry were fed four diets containing 28% (diet 1), 32% (diet 2), 36% (diet 3) and 40% (diet 4) protein levels and reared at two water temperatures 28 and 32 °C for 60 days. Fry fed with diet 3 containing 36% protein showed the highest mean final body weight at 32 °C. Final body weight was significantly (P<0.05) affected by dietary treatments and temperatures. Clarias batrachus fry raised at 28 °C had higher feed efficiency (93.20%) than the fry reared at 32 °C (87.58%) with 28% dietary protein level. Further, feed efficiency decreased with increase in dietary protein level. Higher daily protein retention (0.089%) observed at lower (0.0217 g) daily protein intake at 28 °C than 0.0283 g at 32 °C. While, optimal (0.0282 g) daily protein intake showed higher daily weight gain at 32 °C. Productive protein value (% PPV) was maximum (1.76%) at 32 °C than at 28 °C (0.76%). Final body lipid recorded higher value than initial body lipid at both the temperatures. Hepatosomatic index (HSI) observed to have been influenced (P<0.05) by diets and temperatures, while viscerosomatic index (VSI) affected (P<0.05) by only diets and not (P>0.05) by temperatures. The study concluded that the diet 3 containing 36% protein was optimal for growth of C. batrachus fry at both the temperatures.     

The response of Ceratophyllum demersum L. and Myriophyllum spicatum L. to reduced, ambient, and enhanced ultraviolet-B radiation

The response of Ceratophyllum demersum and Myriophyllum spicatum to three levels of UV-B radiation – reduced (ca. 50% reduction), ambient and enhanced UV-B radiation, simulating 17% ozone depletion – is discussed. The research revealed that UV-B stimulated the production of UV-B absorbing compounds in C. demersum, but not in M. spicatum. The relative amount of UV-B absorbing compounds was about four times lower in C. demersum. Enhanced UV-B also affected respiratory potential in C. demersum (on average 3.7 mg O₂/gDM/h), but no effect on M. spicatum (on average 5.5 mg O₂/gDM/h) was detected. Increased need for energy revealed that UV-B radiation exerted stress in C. demersum. No changes in chlorophyll a and no disturbance to photochemical efficiency due to UV-B were observed in either species.     

Growth strategy of an emergent macrophyte, Typha orientalis Presl, in comparison with Typha latifolia L. and Typha angustifolia L.

The growth strategy of an emergent plant, Typha orientalis Presl, was examined in experimental ponds in comparison with two other Typha species distributed in Japan, Typha latifolia L. and Typha angustifolia L. T. orientalis showed the greatest ability of vegetative reproduction at the expense of growth in height. T. orientalis started to produce new ramets earlier than T. latifolia and T. angustifolia. These results suggest that T. orientalis should be a rather pioneer-like species and would be restricted to disturbed habitats.     

Extract of Ocimum canum lowers blood glucose and facilitates insulin release by isolated pancreatic β-islet cells

Aqueous extract of Ocimum canum Sim, (Lamiaceae) is used by some Ghanaians to manage diabetes mellitus. In vivo modulation of levels of fasting blood glucose by 0. canum extract was evaluated in type-II diabetes mellitus using the C57BL/KsJ db/db genetically diabetic animal model, and its effects on glucose-stimulated insulin release in vitro were monitored using isolated rat pancreatic beta-islet cells. The results showed that fasting blood glucose levels and body weight decreased significantly (p < 0.05) in diabetic and non-diabetic C57BL/KsJ mice, which were administered aqueous extract of 0. canum. In vitro, the 0. canum extract significantly enhanced insulin release from isolated rat pancreatic beta-islet cells. Insulin release was found to be dependent on glucose concentration and increased with increasing O. canum concentration in the incubation medium up to an optimum extract concentration of 0.03 mg/ml. Release of the hormone decreased beyond this concentration of extract in the medium. Addition to the medium of Desmodium adscendens, a plant preparation used to manage inflammatory disorders, did not increase but rather inhibited insulin secretion by the pancreatic beta-islet cells. These results could explain the use of 0. canum in Ghanaian folk medicine to manage diabetes mellitus.     

Response of cytokinin concentration in the xylem exudate of bean (Phaseolus vulgaris L.) plants to decapitation and auxin treatment,and relationship to apical dominance

When xylem exudate of previously untreated Phaseolus vulgaris plants was analysed for cytokinins by radioimmunoassay, a low concentration (about 5 ng · ml^–1) was found. However, when the plants were decapitated about 16 h before the xylem exudate was collected, an almost 25-fold increase in cytokinin concentration was observed. Twenty-four hours after decapitation this increase even reached 4000 compared to control plants. Applying naphthaleneacetic acid (NAA) to the shoot of decapitated plants almost eliminated the effect of shoot tip removal on cytokinin concentration, suggesting that cytokinins in the xylem exudate of intact plants are under the control of the polar auxin transport system. Other xylem constituents, such as potassium or free amino acids did not show this strong increase after decapitation and did not respond to NAA application. It is concluded that the observed auxin/cytokinin interaction has an important regulatory role to play, not only in apical dominance but in many other correlative events as well.Abbreviations AD apical dominance - CKs cytokinin(s) - iAde/iAdo isopentenyladenine/iospentenyladenosine - NAA naphthaleneacetic acid - Z/ZR zeatin/zeatin riboside     

Fungal injury to seed tissues of Norway spruce,Picea abies (L.) Karst.

Norway spruce bore an abundance of cones in Finland in 2000, but these cones were often fungal-infected. The seeds had structural injuries that were revealed when seed samples were examined using light (LM) and a field emission scanning electron microscope (FESEM). Two main types of spores were found either in the tissues inside the seed coat or on the sarcotesta, the outermost layer of seed coat. The spores of Chrysomyxa pirolata appeared particularly in the nucellar tissue, where the cell walls were disintegrated at the middle lamellae and cytoplasm was disrupted. Degenerated remnants of fungal structures resembling aecial peridium were found close to aeciospores. The tissue of the megagametophyte differed also from that of a normal mature seed. Conidia of Thysanophora penicillioides were often encountered on the sarcotesta where the ordinary wax cover was missing. Fungal injury occurred in the nucellar layers that shelter the embryo and megagametophyte from desiccation and oxidation. Destruction of these structures together with rapid opening of the seed coat advance deterioration of seeds during storage and may cause unexpected economic losses in forest plant production.     

Sensitivity of Asellus aquaticus (L.) and Proasellus coxalis Dollf. (Crustacea,Isopoda) to Copper

The effects of Copper on the life-cycle of two crustacean isopods, Asellus aquaticus (L.) and Proasellus coxalis Dollf., are studied. ST₅₀ indicates that females and males are differently sensitive in comparison with juveniles. The two species do not show differences in sensitivity in the range of 0.01–15 mg·1^-1 between adults and juveniles. The effect of 0.005 mg·1^-1 Copper sulphate was strongest on embryonic and larval stages. Ecological implications are discussed.     

Taxonomic studies on three marine pleurostomatid ciliates, Litonotus bergeri nov. spec., L. blattereri nov. spec. and L. petzi nov. spec. (Ciliophora, Pleurostomatida) from North China Sea

The morphology and infraciliature of three pleurostomatid ciliates, Litonotus bergeri nov. spec., L. blattereri nov. spec. and L. petzi nov. spec., collected from mariculture ponds near Qingdao (Tsingtao), China, were investigated using live observations and the protargol impregnation method. These new species are distinguished from their congeners by a combination of characters including the typical distribution of extrusomes, i.e., along entire ventral margin, the number of macronuclear nodules, features and number of somatic kineties, living morphology, number and position of contractile vacuoles and their marine biotopes. Considering the distribution of extrusomes and general morphology, five new combinations are suggested, Litonotus vermiforme (Sauerbrey, 1928) nov. comb. [basionym: Loxophyllum vermiforme Sauerbrey, 1928], Litonotus levigatum (Sauerbrey, 1928) nov. comb. [basionym: Loxophyllum levigatum Sauerbrey, 1928], Litonotus undulatum (Sauerbrey, 1928) nov. comb. [basionym: Loxophyllum undulatum Sauerbrey, 1928], Loxophyllum pictus (Gruber, 1884) nov. comb. [basionym: Litonotus pictus Gruber, 1884] and Loxophyllum trichocystiferus (Foissner, 1984) nov. comb. [basionym: Litonotus trichocystiferus Foissner, 1984].