Bioactive humulene derivatives from Asteriscus vogelii

The bioactive fractions obtained from the extract of Asteriscus vogelii afforded a new humulene derivative, the 8-oxo-6,7,9,10-tetrahydrohumulen-1,12-olide (1), in addition to the known asteriscunolides A (2), C (3) and D (4), and the acids 8-oxo-alpha-humula-6Z,9Z-dien-12-oic acid (5), 8-oxo-alpha-humula-6E,9Z-dien- 12-oic acid (6) and 8-oxo-alpha-humula-6E,9E-dien-12-oic acid (7), characterized as their methyl esters. Evaluation of their phytotoxic and cytotoxic activities was accomplished. Compounds 3 and 4 gave the highest inhibition of plant cell cultures and of the plant Lemna paucicostata. Compound 4 was also the most active against P-338 lymphoma in mice, A-549 carcinoma of human lung, HT-29 carcinoma of human colon and MEL-28 human melanoma.     

Carbon monoxide is the heme oxygenase product with a pyretic action: evidence for a cGMP signaling pathway

We have recently reported that the central heme oxygenase (HO) pathway has an important role in the genesis of lipopolysaccharide fever. However, the HO product involved, i.e., biliverdine, free iron, or carbon monoxide (CO), has not yet been identified with certainty. Therefore, in the present study, we tested the thermoregulatory effects of all HO products. Body core temperature (T(c)) and gross activity of awake, freely moving rats was measured by biotelemetry. Intracerebroventricular administration of heme-lysinate (152 nmol), which induces the HO pathway, evoked a marked increase in T(c), a response that was attenuated by intracerebroventricular pretreatment with the HO inhibitor zinc deuteroporphyrin 2,4-bis glycol (200 nmol), indicating that an HO product has a pyretic action in the central nervous system (CNS) of rats. Besides, heme-lysinate also increased gross activity, but no correlation was found between this effect and the increase in T(c). Moreover, intracerebroventricular biliverdine or iron salts at 152 nmol, a dose at which heme-lysinate was effective in increasing T(c), produced no change in T(c). Accordingly, intracerebroventricular treatment with the iron chelator deferoxamine elicited no change in basal T(c) and did not affect heme-induced pyresis. However, heme-induced pyresis was completely prevented by the soluble guanylate cyclase (sGC) inhibitor 1H-[1,2,4]oxadiazolo[4,3,-a]quinoxaline-1-one. Because biliverdine and iron had no thermoregulatory effects and CO produces most of its actions via sGC, these data strongly imply that CO is the only HO product with a pyretic action in the CNS.     

Central CO-heme oxygenase pathway raises body temperature by a prostaglandin-independent way.

Recently, the carbon monoxide (CO)-heme oxygenase pathway has been shown to play an important role in fever generation by acting on the central nervous system, but the mechanisms involved have not been assessed. Thus the present study was designed to determine whether prostagandins participate in the rise in body temperature (T(b)) observed after induction of the CO-heme oxygenase pathway in the central nervous system. Intracerebroventricular (ICV) injection of heme-lysinate (152 nmol/4 microl), which is known to induce the CO-heme oxygenase pathway, caused an increase in T(b) [thermal index (TI) = 5.3 +/- 0.5 degrees C. h], which was attenuated by ICV administration of the heme oxygenase inhibitor ZnDPBG (200 nmol/4 microl; TI = 2.5 +/- 1.7 degrees C. h; P < 0.05). No change in T(b) was observed after intraperitoneal injection of the cyclooxygenase inhibitor indomethacin (5 mg/kg), whereas indomethacin at the same dose attenuated the fever induced by ICV administration of lipopolysaccharide (LPS) (10 ng/2 microl) (vehicle/LPS: TI = 4.5 +/- 0.5 degrees C. h; indomethacin/LPS: TI = 1.7 +/- 1.0 degrees C. h; P < 0.05). Interestingly, indomethacin did not affect the rise in T(b) induced by heme-lysinate (152 nmol/4 microl) ICV injection (vehicle/heme: TI = 4.5 +/- 1.4 degrees C. h; indomethacin/heme: TI = 4.2 +/- 1.0 degrees C. h). Finally, PGE(2) (200 ng/2 microl) injected ICV evoked a rise in T(b) that lasted 1.5 h. The heme oxygenase inhibitor ZnDPBG (200 nmol/4 microl) failed to alter PGE(2)-induced fever. Taken together, these results indicate that the central CO-heme oxygenase pathway increases T(b) independently of prostaglandins.     

Indomethacin impairs LPS-induced behavioral fever in toads.

We tested the hypothesis that PGs mediate lipopolysaccharide (LPS)-induced behavioral fever in the toad Bufo paracnemis. Measurements of preferred body temperature (T(b)) were performed with a thermal gradient. Toads were injected intraperitoneally with the cyclooxygenase inhibitor indomethacin (5 mg/kg), which inhibits PG biosynthesis, or its vehicle (Tris) followed 30 min later by LPS (0.2 and 2 mg/kg) into the lymph sac. LPS at the dose of 0.2 mg/kg caused a significant increase in T(b) from 7 to 10 h after injection, and then T(b) returned toward baseline values. LPS at the dose of 2 mg/kg produced a different pattern of response, with a longer latency to the onset of fever (10th h) and a longer duration (until the end of the experiment at the 15th h). Tris significantly attenuated the fever induced by LPS at 0.2 mg/kg, but not at 2 mg/kg. Moreover, indomethacin completely blocked the fever evoked by LPS (2 mg/kg). These results indicate that the behavioral fever induced by LPS in toads requires the activation of the COX pathway, suggesting that the involvement of PG in fever has an ancient phylogenetic history and that endogenous PGs raise the thermoregulatory set point to produce fever, because behavioral thermoregulation seems to be related to changes in the thermoregulatory set point.     

Temperature and respiratory function in ectothermic vertebrates

Pulmonary ventilation is adjusted to maintain balance between O₂ demands and CO₂ elimination, which is essential for acid–base status in land ectothermic vertebrates. Rising temperatures cause increases in O₂ consumption (Q₁₀ effect) and decreases in the O₂ affinity of hemoglobin (a rightward shift in the oxygen–hemoglobin dissociation curve). These changes in air-breathing ectotherms are not proportional, i.e., the increased ventilation is relatively smaller than the change in metabolic rate. Therefore, the ratio between ventilation and metabolic rate is reduced, and consequently blood pH changes inversely with temperature. The combination of high temperatures and hypoxia exposure results in an amplified increase of ventilation, which may be explained by the balance between increased O₂-demand and decreased O₂-supply as well as increased O₂-chemoreceptors sensitivity. High temperature also increases pulmonary diffusing capacity. Global warming is expected to have significant impacts on the world’s climate, with temperature changes affecting living organisms, in relation to their physiology and distribution. These physiological mechanisms and their capacity to respond appropriately to temperature illustrate the complexity of the relationship between ambient temperature and the respiratory function in ectothermic vertebrates, which are particularly susceptible to change in their environment.     

The Use of an Automated System (GreenFeed) to Monitor Enteric Methane and Carbon Dioxide Emissions from Ruminant Animals

Ruminant animals (domesticated or wild) emit methane (CH₄) through enteric fermentation in their digestive tract and from decomposition of manure during storage. These processes are the major sources of greenhouse gas (GHG) emissions from animal production systems. Techniques for measuring enteric CH₄ vary from direct measurements (respiration chambers, which are highly accurate, but with limited applicability) to various indirect methods (sniffers, laser technology, which are practical, but with variable accuracy). The sulfur hexafluoride (SF₆) tracer gas method is commonly used to measure enteric CH₄ production by animal scientists and more recently, application of an Automated Head-Chamber System (AHCS) (GreenFeed, C-Lock, Inc., Rapid City, SD), which is the focus of this experiment, has been growing. AHCS is an automated system to monitor CH₄ and carbon dioxide (CO₂) mass fluxes from the breath of ruminant animals. In a typical AHCS operation, small quantities of baiting feed are dispensed to individual animals to lure them to AHCS multiple times daily. As the animal visits AHCS, a fan system pulls air past the animal’s muzzle into an intake manifold, and through an air collection pipe where continuous airflow rates are measured. A sub-sample of air is pumped out of the pipe into non-dispersive infra-red sensors for continuous measurement of CH₄ and CO₂ concentrations. Field comparisons of AHCS to respiration chambers or SF₆ have demonstrated that AHCS produces repeatable and accurate CH₄ emission results, provided that animal visits to AHCS are sufficient so emission estimates are representative of the diurnal rhythm of rumen gas production. Here, we demonstrate the use of AHCS to measure CO₂ and CH₄ fluxes from dairy cows given a control diet or a diet supplemented with technical-grade cashew nut shell liquid.     

Caffeine Ingestion Increases Estimated Glycolytic Metabolism during Taekwondo Combat Simulation but Does Not Improve Performance or Parasympathetic Reactivation

ObjectivesThe aim of this study was to evaluate the effect of caffeine ingestion on performance and estimated energy system contribution during simulated taekwondo combat and on post-exercise parasympathetic reactivation.MethodsTen taekwondo athletes completed two experimental sessions separated by at least 48 hours. Athletes consumed a capsule containing either caffeine (5 mg∙kg^-1) or placebo (cellulose) one hour before the combat simulation (3 rounds of 2 min separated by 1 min passive recovery), in a double-blind, randomized, repeated-measures crossover design. All simulated combat was filmed to quantify the time spent fighting in each round. Lactate concentration and rating of perceived exertion were measured before and after each round, while heart rate (HR) and the estimated contribution of the oxidative (W_AER), ATP-PCr (W_PCR), and glycolytic (W_[La-]) systems were calculated during the combat simulation. Furthermore, parasympathetic reactivation after the combat simulation was evaluated through 1) taking absolute difference between the final HR observed at the end of third round and the HR recorded 60-s after (HRR_60s), 2) taking the time constant of HR decay obtained by fitting the 6-min post-exercise HRR into a first-order exponential decay curve (HRR_τ), or by 3) analyzing the first 30-s via logarithmic regression analysis (T30).ResultsCaffeine ingestion increased estimated glycolytic energy contribution in relation to placebo (12.5 ± 1.7 kJ and 8.9 ± 1.2 kJ, P = 0.04). However, caffeine did not improve performance as measured by attack number (CAF: 26. 7 ± 1.9; PLA: 27.3 ± 2.1, P = 0.48) or attack time (CAF: 33.8 ± 1.9 s; PLA: 36.6 ± 4.5 s, P = 0.58). Similarly, RPE (CAF: 11.7 ± 0.4 a.u.; PLA: 11.5 ± 0.3 a.u., P = 0.62), HR (CAF: 170 ± 3.5 bpm; PLA: 174.2 bpm, P = 0.12), oxidative (CAF: 109.3 ± 4.5 kJ; PLA: 107.9 kJ, P = 0.61) and ATP-PCr energy contributions (CAF: 45.3 ± 3.4 kJ; PLA: 46.8 ± 3.6 kJ, P = 0.72) during the combat simulation were unaffected. Furthermore, T30 (CAF: 869.1 ± 323.2 s; PLA: 735.5 ± 232.2 s, P = 0.58), HRR_60s (CAF: 34 ± 8 bpm; PLA: 38 ± 9 bpm, P = 0.44), HRRτ (CAF: 182.9 ± 40.5 s, PLA: 160.3 ± 62.2 s, P = 0.23) and HRR_amp (CAF: 70.2 ± 17.4 bpm; PLA: 79.2 ± 17.4 bpm, P = 0.16) were not affected by caffeine ingestion.ConclusionsCaffeine ingestion increased the estimated glycolytic contribution during taekwondo combat simulation, but this did not result in any changes in performance, perceived exertion or parasympathetic reactivation.     

Cyanobacteria in mangrove ecosystems

Mangroves are subject to the effects of tides and fluctuations in environmental conditions, which may reach extreme conditions. These ecosystems are severely threatened by human activities despite their ecological importance. Although mangroves are characterized by a highly specialized but low plant diversity in comparison to most other tropical ecosystems, they support a diverse microbial community. Adapted microorganisms in soil, water, and on plant surfaces perform fundamental roles in nutrient cycling, especially nitrogen and phosphorus. Cyanobacteria contribute to carbon and nitrogen fixation and their cells act as phosphorus storages in ecosystems with extreme or oligotrophic environmental conditions such as those found in mangroves. As the high plant productivity in mangroves is only possible due to interactions with microorganisms, cyanobacteria may contribute to these ecosystems by providing fixed nitrogen, carbon, and herbivory-defense molecules, xenobiotic biosorption and bioremediation, and secreting plant growth-promoting substances. In addition to water, cyanobacterial colonies have been detected on sediments, rocks, decaying wood, underground and aerial roots, trunks, and leaves. Some mangrove cyanobacteria were also found in association to algae or seagrasses. Few studies on mangrove cyanobacteria are available, but together they have reported a substantial number of species in these ecosystems. However, the cyanobacterial diversity in this biome has been traditionally underestimated. Though mangrove communities generally host cyanobacterial taxa commonly found in marine environments, unique microhabitats found in mangroves potentially harbor several undescribed cyanobacterial taxa. The relevance of cyanobacteria for mangrove conservation is highlighted in their use for the recovery of degraded mangroves as biostimulants or in bioremediation.     

Morphological differences among egg nests and adult individuals of Cicadatra persica (Hemiptera,Cicadidae), distributed in Erneh,Syria

The aim of this study is determining the different patterns of egg nests and the morphological differences between the specimens of Cicadatra persica Kirkalidy, 1909 (Hemiptera: Cicadidae) distributed in fruit orchards in Erneh located on AL-Sheikh mountain south west of Syria. The appearance of 80 egg nests was studied, and the results showed that there were two basic patterns of egg nests laid by Cicadatra persica, 90% of the egg nests were of the first pattern (consists of several adjacent slits), while 10% of them were of the second pattern (consists of several divergent slits). A random sample consisting of 300 specimens (150 males and 150 females) were also studied concentrating on the differences in the color of the supra-antennal plate and in the number of spurs on the tibia of the hind legs. The results showed that there were two basic patterns of individuals based on the differences in the color of supra-antennal plate. The first pattern (individuals with yellow supra-antennal plates), constituted more than 90%, and the second one (individuals with black supra-antennal plates) constituted less than 10%. The results also showed that there were 27 different patterns based on the number of spurs on the tibia of the hind legs. One of them was a common pattern (2, 3) whose individuals have 2 spurs on the upper side of the tibia of the hind legs and 3 spurs on the lateral side of the tibia of the hind legs. The total percent of this common pattern was 76%. The other 26 patterns were different from each other, and the total percent of all these different patterns was 24%.     

Collagenase predigestion on paraffin sections enhances collagen immunohistochemical detection without distorting tissue morphology

Reliable immunohistochemical detection of collagen in formalin fixed, paraffin embedded tissues requires protease digestion. While these pan-proteases (pepsin, trypsin, protease K, etc.) enhance collagen detection, they also digest many other tissue proteins and produce poor cellular morphology and unrecognizable cellular structures. Balancing the conditions (protease type, concentration, incubation time and temperature) to digest some, but not all, proteins in a tissue section while optimizing collagen detection requires one to compromise improved collagen immunolabeling with adequate cellular morphology. Furthermore, optimal conditions for digesting tissue proteins to enhance collagen detection vary among tissue types and their fixation. Although brain is not typically subject to these deleterious consequences, structures such as epithelium, spermatids, stroma etc. and other tissues with complicated histology are profoundly affected. To resolve this technical dilemma, we discovered a novel use for collagenase to enhance collagen immunodetection without affecting the noncollagen proteins, thereby preserving tissue morphology. Collagenase, which is typically used in vitro for disassociation of cells, has never been used reliably on formalin fixed, paraffin embedded tissue sections. This new use of collagenase for immunohistochemistry promotes increased collagen immunolabeling, is easy to use, is versatile, and allows preservation of tissue structure that provides maximal and accurate histological information.