Verrucosamide,a Cytotoxic 1,4-Thiazepane-Containing Thiodepsipeptide from a Marine-Derived Actinomycete

A new cytotoxic thiodepsipeptide, verrucosamide (1), was isolated along with the known, related cyclic peptide thiocoraline, from the extract of a marine-derived actinomycete, a Verrucosispora sp., our strain CNX-026. The new peptide, which is composed of two rare seven-membered 1,4-thiazepane rings, was elucidated by a combination of spectral methods and the absolute configuration was determined by a single X-ray diffraction study. Verrucosamide (1) showed moderate cytotoxicity and selectivity in the NCI 60 cell line bioassay. The most susceptible cell lines were MDA-MB-468 breast carcinoma with an LD₅₀ of 1.26 µM, and COLO 205 colon adenocarcinoma with an LD₅₀ of 1.4 µM. Also isolated along with verrucosamide were three small 3-hydroxy(alkoxy)-quinaldic acid derivatives that appear to be products of the same biosynthetic pathway.     

Getting cosy in freshwater: Assumed to be brackish pike are not so brackish after all

Pike (Esox lucius) occupy coastal streams and rivers of the Baltic Sea, where they attain large sizes (>5 kg). These large sizes are perhaps due to the fact that they can tolerate relatively high salinities and can thus forage in the nearby more productive brackish environments. In an attempt to quantify the extent to which pike utilise brackish environments, and to provide some insight into the underlying causes for brackish water migrations, we tagged 30 pike from a western Baltic river with acoustic transmitters and were able to track 21 individuals for 1 year. Based on experienced from local anglers, this population was assumed to be brackish in nature, where individuals underwent freshwater migrations to spawn. Our findings however suggest that the smallest and most active individuals make short exits into brackish waters and do so on rare occasions. Our results further indicate that neither sex nor size is related to activity level. We suggest that these patterns reflect two distinct behaviours—active and passive—and that large pike can be supported by the food availability in the river, without the need to venture into coastal zones, thus defying the conventional view that Baltic pike are all brackish in nature.     

The value of sea urchin,Lytechinus variegatus,egesta consumed by shrimp,Litopenaeus vannamei

Sea urchins produce high‐energy, membrane‐bound fecal pellets that contain residual nutrients and large quantities of microbiota. These egesta are readily consumed by the shrimp, Litopenaeus vannamei. Egesta of the sea urchin, Lytechinus variegatus, were evaluated as a feed supplement or total replacement for a commercial shrimp diet. Shrimp were stocked at 0.49 g ± 0.06 g initial body weight and housed individually in 2.8‐L tanks in a commercial recirculating zebrafish system. Shrimp were assigned to one of six diets: commercial shrimp feed, reference sea urchin feed, collected dried sea urchin egesta, collected wet sea urchin egesta, half ration of shrimp feed and half collected wet sea urchin egesta, and egesta naturally produced by two sea urchins in polyculture. Equivalent dry matter amounts of each diet were proffered to shrimp in each treatment twice daily, except for those that had complete access to natural egesta excreted by sea urchins in polyculture. Sea urchins were proffered a reference sea urchin feed at 2% body weight daily. After 27 days, shrimp proffered collected dried or wet egesta did not differ significantly in percent weight gain and showed the lowest weight gain. The percent weight gain of shrimp fed the commercial shrimp diet did not differ significantly from that of the shrimp fed half commercial shrimp diet and half egesta. The highest weight gain was recorded for those shrimp that consumed the untouched egesta produced by sea urchins in polyculture. These data suggest that consumed egesta have noteworthy nutritional value and therefore would be beneficial to the culture of extractive species in an integrated multitrophic aquaculture system.     

Early interspecific dynamics,dry matter production and nitrogen use in Kernza (Thinopyrum intermedium) – alfalfa (Medicago sativa L.) mixed intercropping

ABSTRACT

The global interest in growing perennial grain crops such as intermediate wheatgrass (Thinopyrum intermedium) (Kernza) for production of food and feed is increasing. Intercropping Kernza with legumes may be a sustainable way of supplying nitrogen to soil and associated intercrop. We determined the competitive interactions between intercropped Kernza (K) and alfalfa (Medicago sativa L.) (A) under three inorganic nitrogen (N) rates N0, N1, N2 (0, 200, 400 kg ha^?1) and five species relative frequencies (SRF) (100%K:0%A, 75%K:25%A, 50%K:50%A, 25%K:75%A and 0% K:100%A) in mixed intercrops (MI) in a greenhouse pot experiment. After 11 weeks of growth. Kernza dry matter yield (DM) and N accumulated (NACC) were low, but alfalfa DM and NACC high at 0 kg N ha^?1. 200 and 400 kg N ha^?1 fertiliser application increased the competitive ability (CA) of Kernza and reduced the CA of alfalfa. SRF had large impacts on alfalfa DM, NACC and NFIX only at 0 kg N ha^?1 fertiliser, and insignificant impacts on Kernza at all N fertiliser levels, indicating that adjustment of SRF may not be an effective way to modulate the interspecific competition of Kernza. Further research on the other factors that influence the interspecific competition are warranted.     

Intercropping fenugreek (Trigonella foenum‐graecum L.) and barley (Hordeum vulgare L.) with and without biochar: Tests along a competition gradient

Integrating soil amendment biochar to legume‐based intercropping systems may amplify the intercropping benefits and lead to more sustainable production due to its positive effects on the soil physicochemical and biological environment. Fenugreek (Trigonella foenum‐graecum) is a legume used in an intercropping system in several countries in Southern Europe, the Middle East, and Asia. A barley cultivar and an Iranian fenugreek ecotype were studied in two replacement series experiments to find the best combination of the two species as well as the effect of adding biochar to the soil. Fenugreek and barley were grown in 4‐L pots in five density combinations (20:0, 15:5, 10:10, 5:15, 0:20) with and without application of biochar in sandy loam soil. The biomass, nitrogen (N) and carbon (C) amount of the two crops were measured fifty days after sowing, and the Relative Yield Total (RYT) was estimated. Our results showed that biochar application resulted in a higher total biomass, N and C amount in all combinations of fenugreek and barley. Total biomass was increased by biochar 19.2% when fenugreek was grown alone and 8.1 and 12.9% in series with 25 and 50% barley when biochar was added, respectively. Biochar increased dry matter, N and C accumulation in both crop species in the mixtures. An exception was the C amount of barley which was not influenced by biochar in intercropping. RYT values were largest for biomass, C and N amount in mixtures with 15 fenugreek plants per pot and 5 barley plants per pot corresponding to approximately 400 fenugreek plants per m mixed with 130 barley plants per m². Biochar application increased RYT of the total dry weight by 2.7 and 5.5% in mixtures of 25 and 50% barley plants, RYT of the total nitrogen by 0.8% in mixtures with 25% barley plants, and RYT of the total carbon by 2.7 and 6.6% in mixtures with 25 and 50% barley plants. The RYT values declined with increasing number of barley plants as a result of a less competitive ability of fenugreek when growing in high barley densities. The yield was highest with intercropping but monoculture of barley also resulted in high yields. The total highest yield was found when approximately 130 fenugreek plants per m² were mixed with 400 barley plants per m². Mixtures with 75% fenugreek and 25% barley obtained RYT values larger than 1 for biomass, carbon and nitrogen percentages.     

Intravenous sufentanil‐midazolam versus sevoflurane anaesthesia in medetomidine pre‐medicated Himalayan rabbits undergoing ovariohysterectomy

ObjectiveTo compare physiological effects of sufentanil-midazolam with sevoflurane for surgical anaesthesia in medetomidine premedicated rabbits.Study designProspective, randomized controlled experimental study.AnimalsEighteen female Himalayan rabbits, weight 2.1 ± 0.1 kg.MethodsPremedication with 0.1 mg kg⁻¹ medetomidine and 5 mg kg⁻¹ carprofen subcutaneously, was followed by intravenous anaesthetic induction with sufentanil (2.3 μg mL⁻¹) and midazolam (0.45 mg mL⁻¹). After endotracheal intubation, anaesthesia was maintained with sufentanil-midazolam (n = 9) or sevoflurane (n = 9). Ovariohysterectomy was performed. Intermittent positive pressure ventilation was performed as required. Physiological variables were studied perioperatively. Group means of physiologic data were generated for different anaesthetic periods. Data were compared for changes from sedation, and between groups by anova. Post-operatively, 0.05 mg kg⁻¹ buprenorphine was administered once and 5 mg kg⁻¹ carprofen once daily for 2–3 days. Rabbits were examined and weighed daily until one week after surgery.ResultsSmooth induction of anaesthesia was achieved within 5 minutes. Sufentanil and midazolam doses were 0.5 μg kg⁻¹ and 0.1 mg kg⁻¹, during induction and 3.9 μg kg⁻¹ hour⁻¹ and 0.8 mg kg⁻¹ hour⁻¹ during surgery, respectively. End-tidal sevoflurane concentration was 2.1% during surgery. Assisted ventilation was required in nine rabbits receiving sufentanil-midazolam and four receiving sevoflurane. There were no differences between groups in physiologic data other than arterial carbon dioxide. In rabbits receiving sevoflurane, mean arterial pressure decreased pre-surgical intervention, heart rate increased 25% during and after surgery and body weight decreased 4% post-operatively. Post-operative problems sometimes resulted from catheterization of the ear artery.ConclusionSevoflurane and sufentanil-midazolam provided surgical anaesthesia of similar quality. Arterial blood pressure was sustained during sufentanil-midazolam anaesthesia and rabbits receiving sevoflurane lost body weight following ovariohysterectomy. Mechanical ventilation was required with both anaesthetic regimens.Clinical relevanceAnaesthesia with sufentanil-midazolam in medetomidine premedicated healthy rabbits is useful in the clinical and the research setting, as an alternative to sevoflurane.     

Assessing the influence of mechanical ventilation on blood gases and blood pressure in rattlesnakes

ObjectiveTo characterize the impact of mechanical positive pressure ventilation on heart rate (HR), arterial blood pressure, blood gases, lactate, glucose, sodium, potassium and calcium concentrations in rattlesnakes during anesthesia and the subsequent recovery period.Study designProspective, randomized trial.AnimalsTwenty one fasted adult South American rattlesnakes (Crotalus durissus terrificus).MethodsSnakes were anesthetized with propofol (15 mg kg⁻¹) intravenously, endotracheally intubated and assigned to one of four ventilation regimens: Spontaneous ventilation, or mechanical ventilation at a tidal volume of 30 mL kg⁻¹ at 1 breath every 90 seconds, 5 breaths minute⁻¹, or 15 breaths minute⁻¹. Arterial blood was collected from indwelling catheters at 30, 40, and 60 minutes and 2, 6, and 24 hours following induction of anesthesia and analyzed for pH, PaO₂, PaCO₂, and selected variables. Mean arterial blood pressure (MAP) and HR were recorded at 30, 40, 60 minutes and 24 hours.ResultsSpontaneous ventilation and 1 breath every 90 seconds resulted in a mild hypercapnia (PaCO₂ 22.4 ± 4.3 mmHg [3.0 ± 0.6 kPa] and 24.5 ± 1.6 mmHg [3.3 ± 0.2 kPa], respectively), 5 breaths minute⁻¹ resulted in normocapnia (14.2 ± 2.7 mmHg [1.9 ± 0.4 kPa]), while 15 breaths minute⁻¹ caused marked hypocapnia (8.2 ± 2.5 mmHg [1.1 ± 0.3 kPa]). Following recovery, blood gases of the four groups were similar from 2 hours. Anesthesia, independent of ventilation was associated with significantly elevated glucose, lactate and potassium concentrations compared to values at 24 hours (p < 0.0001). MAP increased significantly with increasing ventilation frequency (p < 0.001). HR did not vary among regimens.Conclusions and clinical relevanceMechanical ventilation had a profound impact on blood gases and blood pressure. The results support the use of mechanical ventilation with a frequency of 1–2 breaths minute⁻¹ at a tidal volume of 30 mL kg⁻¹ during anesthesia in fasted snakes.     

Plywood frame corner joints with glued-in hardwood dowels

This paper presents research on plywood frame corners jointed to glulam beams and columns by means of glued-in hardwood dowels. The frame corner was made of a solid block of ordinary plywood of the same width as the glulam beams and with plies parallel to the plane of the frame to avoid splitting due to stress perpendicular to the grain. Hardwood dowels with a diameter of 12mm and a maximum glued-in length of 120mm were glued into drilled holes in the plywood corner and glulam beam ends parallel to the grain direction of the beams to form a momentresisting joint. Static bending tests were conducted of frame corners with 100 X 200mm² and 120 X 420mm² beam cross sections. Bending capacities of the joints corresponding to a modulus of rupture of the jointed glulam beams of about 30MPa were obtained for both closing and opening moments for the small cross sections, and about 22MPa was obtained for the large cross sections. Simple design models for calculation of joint strength and rotational stiffness are also presented.     

Necrophylactic periderm formation in the roots of western larch and Douglas‐fir trees infected with Armillaria ostoyae. II. The response to the pathogen

Periderm formation was studied in bark samples collected from the roots of western larch (Larix occidentalis) and Douglas‐fir (Pseudotsuga menziesii) trees infected with Armillaria ostoyae. Necrophylactic periderms were formed in advance of infection and successfully restricted continued fungal spread in 68 and 45% of the samples collected from 10‐ and 27‐year‐old western larch, respectively. However, all periderms formed in 11‐ and 25‐year‐old Douglas‐fir had been breached by the advancing fungus. In both species, necrophylactic periderms were commonly breached at the junction of the periderm with the vascular cambium. In western larch, stone phellem often comprised the external phellem layer of necrophylactic periderms with multiple bands of phellem. In 27‐year‐old western larch, infection was often confined to discrete lesions bounded by multiple periderms with multiple bands of phellem. In both tree species, phellem production was greater in response to infection than in response to abiotic wounding.