Effect of environmental conditions on decomposition in eight woody species of a dry tropical forest

Litter decay is a significant part of carbon budget. Due to strong environmental control, the changes in the environment may drastically influence the litter decay rates. Litter decomposition of eight dry tropical woody species, viz. Shorea robusta, Buchanania lanzan, Diospyros melanoxylon, Lagerstroemia parviflora, Lannea coromandelica, Terminalia tomentosa, Holarrhena antidysenterica and Lantana camara was studied to document the effect of intra-annual changes in the environment. Litter decomposition was monitored at monthly intervals at five sites using litter bag technique over an annual cycle in a dry tropical deciduous forest of Vindhyan highland, India. Weight loss differed among species and through months, and ranged from 15.38% in L. camara at Kotwa site in January to 30.72% in T. tomentosa at Hathinala site in August. Peak weight loss occurred in August and averaged 46.2% across species and sites. Nitrogen and phosphorus mineralization rates also varied significantly from species to species. T. tomentosa having higher nitrogen content and lower C/N ratio than other species exhibited faster weight loss. Nitrogen and phosphorus contents of litter showed significant positive correlation with weight loss. C/N ratio was negatively related to decay constant, and the weight loss was positively related to the soil surface temperature as well as soil moisture content.     

Cell-free DNA as a prognostic marker in stage I non-small-cell lung cancer patients undergoing stereotactic body radiotherapy

Abstract

Objective: To evaluate whether plasma cell-free DNA (cfDNA) was related to clinical outcome in inoperable stage I non-small cell lung cancer (NSCLC) patients undergoing stereotactic body radiotherapy (SBRT).

Materials and methods: Plasma cfDNA was assessed at baseline, before the last day and 45 days after the end of SBRT, in 22 NSCLC patients. Twenty-two healthy controls were also evaluated.

Results: Plasma cfDNA was higher in patients than in controls. An association with unfavourable disease-free survival was found for continuous baseline cfDNA increments (HR?=?5.9, 95%CI: 1.7–19.8, p?=?0.04).

Conclusion: Plasma cfDNA may be a promising prognostic biomarker in high-risk NSCLC patients.     

THE PROCESSING OF UNCONFINED,NATURALLY ENTRAINED LEAVES IN TWO LOW-ORDER SOUTHERN AFRICAN MOUNTAIN STREAMS

Summary

Breakdown of unconfined and confined leaves of the riparian tree Brabejum stellatifolium L. was investigated in two low order mountain streams (Window Stream and Langrivier) in the southwestern Cape, South Africa. At both sites, 5000 unconfined leaves were released in April and another 5000 in December 1990. The leaves were marked and half of them presoaked in river water prior to release. Leaves reaching a net 100 m below the point of release were removed periodically. On termination of the experiments, the study reaches were cleared of the remaining marked leaves. The distance which these leaves had travelled, and the retentive feature at which they were found were recorded. All leaves were weighed after recovery. In December 1990, leaves confined in coarse-mesh bags were placed on the stream beds of the two sites. Decay rates of unconfined leaves differed between streams and seasons but not between wetted and dry leaves or those of contrasting initial size and weight. In winter, breakdown of unconfined leaves was rapid (t₅₀ of 6.6d and 23.9d for Langrivier and Window Stream respectively). In summer, breakdown of unconfined leaves was slower (t₅₀ of 58d, Langrivier), but more rapid than leaves confined in mesh bags (t₅₀ of 77d, Langrivier). Distance travelled downstream had no significant effect on leaf breakdown. Different retentive features resulted in different rates of decay. Leaf weight loss in winter and summer at both sites was greatest in riffles (17–80%) and runs (21–78%). In all cases, stranded (exposed and out of the water) leaves lost the least weight (4–38%).     

支气管动脉灌注化疗与栓塞治疗中晚期肺癌的疗效观察

目的：对比分析支气管动脉灌注化疗与支气管动脉灌注化疗十栓塞术治疗中晚期肺癌的临床疗效。方法：将我院2011年1月-2013年1月期间收治的76例中晚期肺癌患者随机分为两组,即观察组38例,对照组38例。观察组患者行支气管动脉灌注化疗联合栓塞术治疗,对照组患者行单纯支气管动脉灌注化疗治疗。分别对两组患者治疗后的临床治疗效果进行评价,同时观察两组患者治疗后的不良反应及并发症的发生情况。结果：观察组患者临床治疗的总有效率为84．21％,对照组为64．78％．两组比较,差异具有统计学意义（P〈0．05）。两组患者治疗后,观察组患者总不良反应率为23．67％,对照组为21．04％,两组比较．差异无统计学意义（P〉0．05）。且经对症处理后,均得到有效改善。结论：支气管动脉灌注化疗联合栓塞术治疗中晚期肺癌的,临床疗效明显优于单纯支气管动脉灌注化疗,且无明显不良反应及并发症的发生,安全性好,值得临床推广与应用。     

Evolution of larval segment position across 12 Drosophila species*

Many developmental traits that are critical to the survival of the organism are also robust. These robust traits are resistant to phenotypic change in the face of variation. This presents a challenge to evolution. In this article, we asked whether and how a well-established robust trait, Drosophila segment patterning, changed over the evolutionary history of the genus. We compared segment position scaled to body length at the first-instar larval stage among 12 Drosophila species. We found that relative segment position has changed many times across the phylogeny. Changes were frequent, but primarily small in magnitude. Phylogenetic analysis demonstrated that rates of change in segment position are variable along the Drosophila phylogenetic tree, and that these changes can occur in short evolutionary timescales. Correlation between position shifts of segments decreased as the distance between two segments increased, suggesting local control of segment position. The posterior-most abdominal segment showed the highest magnitude of change on average, had the highest rate of evolution between species, and appeared to be evolving more independently as compared to the rest of the segments. This segment was exceptionally elongated in the cactophilic species in our dataset, raising questions as to whether this change may be adaptive.     

Biostratigraphy and stage boundaries of the upper Cretaceous–early Paleogene successions in southern Galala area,North-Eastern Desert,Egypt

The foraminiferal contents of three surface sections [Gebel Tarboul, Wadi Tarfa (WT) and Bir Dakhl (BD) sections] in southern Galala area, North-Eastern Desert, Egypt, have been studied in detail and used in biostratigraphy and chronostratigraphy of the upper Cretaceous–Paleogene successions. Sixty-nine planktonic foraminiferal species belonging to 23 genera have yielded 17 biozones. They are given in ascending order: Globotruncana aegyptiaca Interval Zone (IZ), Gansserina gansseri IZ, Contusotruncana contusa–Racemiguembelina fructicosa IZ, Abathomphalus mayaroensis IZ, P1c, P2, P3, P3a, P3b, P4, P4a, P4b, P4c, P5, E1, E2, E3, E4 and E5. Moreover, local and widespread regional hiatus was detected in the pelagic to hemipelagic sequence during Cretaceous–Paleogene boundary in southern Galala Sub-basin. This hiatus corresponds to the Early Maastrichtian–Early Eocene in Gebel Tarboul, the interval between Late Maastrichtian–Early Paleocene throughout WT sequences and Late Maastrichtian–Late Paleocene in BD section.     

Subunit Secondary Structure in Filamentous Viruses: Predictions and Observations

Abstract

The algorithm of Gamier, Osguthorpe and Robson (J. Mol. Biol. 120, 97–120, 1978) for prediction of protein secondary structure has been applied to the coat protein sequences of six filamentous bacteriophages: fd, Ifl, IKe, Pfl, Xf and Pf3. For subunits of Class I virions (fd, Ifl, IKe), the algorithm predicts a very high percentage of helix in comparison to other structure types, which is in accord with the results of laser Raman and circular dichroism measurements. For subunits of the Class II virions (Pfl, Xf, Pf3), the algorithm consistently predicts a predominance of β structure, which is compatible with the demonstrated facility for conversion of Class II subunits from α-helix to β-strand under appropriate experimental conditions (Thomas, Prescott and Day, J. Mol. Biol. 165, 321–356, 1983). Even when the algorithm is biased to favor helix, the Class II virion subunits are predicted to contain considerably more strand than helix. Qualitatively similar results are obtained using the algorithm of Chou and Fasman {Adv. Enzym. 47, 45–148,45-148). Therefore, both predictive and experimental methods indicate a distinction between Gass I and II subunits, which is reflected in a greater tendency of the latter to adopt other than uniform β-helical conformation. The results suggest a possible model for the disassembly of filamentous viruses which may involve the unraveling of coat protein helices at the N terminus.     

METAMORPHOSIS OF THE LARVA OF THE POLYCHAETE ARENICOLA CRISTATA. MORPHOLOGY OF THE ‘HOUR-GLASS’ STAGE

The constricted ‘waist’ of the metamorphosing larva of the polychaete Arenicola cristata is described, using light and electron microscopy. The constriction is shown to be the consequence of the discharge and collapse of a post-trochal ring of epithelial cells which remain as functional components of the post-metamorphic juvenile. Morphological differentiation of neuro-effector and interneuronal contacts is initiated at this time. Muscular and neural changes are discussed in terms of their role in effecting metamorphosis.