Cell Division of Escherichia coli: Control by Membrane Organization

Cells of certain strains of Escherichia coli, after transfer from 37 to 45 C and incubation for 16 min, were observed to swell and subsequently divide synchronously. This swelling and the resulting stretching of the membrane are proposed to be the basis for the synchronous division. Four lines of evidence support this hypothesis. First, osmotic protection by the addition of either sodium chloride or sucrose at the time of heat shock prevents both swelling and synchrony. Second, a mutant neither swelled nor divided synchronously after heat shock. Third, cells grown for several generations with 10% sucrose in the medium swelled and divided synchronously upon transfer to medium without sucrose. Fourth, the mutant not synchronized by heat shock also swelled and underwent synchronous division after the osmotic shift. A tentative model is suggested for the normal control of division, based on membrane configuration at the septation site.     

Design,synthesis and biological evaluation of 4-benzoyl-1-dichlorobenzoylthiosemicarbazides as potent Gram-positive antibacterial agents

Twelve 4-benzoyl-1-dichlorobenzoylthiosemicarbazides have been tested as potential antibacterials. All the compounds had MICs between 0.49 and 15.63?µg/ml toward Micrococcus luteus, Bacillus cereus, Bacillus subtilis and Staphylococcus epidermidis indicating, in most cases, equipotent or even more effective action than cefuroxime. In order to clarify if the observed antibacterial effects are universal, further research were undertaken to test inhibitory potency of two most potent compounds 3 and 11 on clinical isolates of Staphylococcus aureus. Compound 11 inhibited the growth of methicillin-sensitive S. aureus (MSSA) at MICs of 1.95–7.81?µg/ml, methicillin-resistant S. aureus (MRSA) at MICs of 0.49–1.95?µg/ml and MDR–MRSA at MIC of 0.98 and 3.90?µg/ml, respectively. Finally, inhibitory efficacy of 3 and 11 on planktonic cells and biofilms formation in clinical isolates of S. aureus and Haemophilus parainfluenzae was tested. The majority of cells in biofilm populations of MSSA and MRSA were eradicated at low level of 3, with MBICs in the range of 7.82–15.63?µg/ml.     

Identifying novel regulators of shoot meristem development

New organs are initiated throughout the life span of higher plants. This process occurs at the shoot meristem, which is initiated during embryogenesis and is later responsible for generating the above-ground portion of the plant. The shoot meristem can be thought of as having two zones, a central zone containing meristematic cells in an undifferentiated state, and a surrounding peripheral zone where cells enter a specific developmental pathway toward a differentiated state. Recent advances have revealed several genes that specifically regulate meristem development inArabidopsis. However, extensive mutagenesis by several labs have identified only a handful, of loci that appear to specifically regulate shoot meristem development. We have undertaken an enhancer/suppressor mutagenesis of an existing meristem mutant (clv1) and have identified novel regulators of meristem development. The extended abstract of a paper presented at the 13th International Symposium in Conjugation with Award of the International Prize for Biology “Frontier of Plant Biology”     

Effect of dexamethasone and hydrocortisone on the course of superovulation in cattle

The effect of hydrocortisone and dexamethasone on superovulation was examined in 12 cows. On the day PMSG was given, each animal received either the first of five daily doses of 250 mg succinate hydrocortisone or one injection of 30 mg dexamethasone. In the 48-hr interval between the injection of PMSG and PGF(2)alpha, the concentration of progesterone rose from 6.97 to 10.22 ng/ml in the experimental groups and only to about 2.8 ng/ml in the control group. In the following days progesterone increased even more, from 15.7 to 26.0 ng/ml seven days after estrus in the experimental group and to 19.25 ng/ml in the control group. The group which received dexamethasone had an average of 4.7 corpora lutea and one embryo flushed per animal. The hydrocortisone group had an average of 2.5 corpora lutea and one cow had two embryos. The control group had 6.2 corpora lutea and 5.2 embryos per animal.     

Leaf micromorphology and leaf glandular hair ontogeny of Myoporum bontioides A. Gray

Myoporum bontioides A. Gray (Myoporaceae), a red list plant in Japan, is restricted to only a few East Asian countries like China, Japan and Taiwan, associated to some true mangroves. The leaf is isolateral and has a thick cuticle; stomata are anomocytic, sunken and have a beak‐shaped cuticular outgrowth at the inner and outer side of the stomatal pore (ledges); profuse glandular hairs are scattered on both leaf surfaces of young leaves. The mesophyll is compact with palisade and spongy parenchyma cells in the young stage, but at maturity profuse intercellular spaces can be observed. Secretory ducts occur in young leaves. Pear‐shaped glandular hairs protrude from the epidermal layer. Hair primordia are well distinct by their larger size and undergo divisions to produce two laterally placed basal cells, two stalk cells and four radiating terminal cells. The cuticle layers of the terminal cells are often separated from the cell wall to form a space, in which ions accumulate for excretion. Inner walls of the basal cells are connected with the mesophyll. Though ontogeny and structure of glandular hairs have resemblance to typical mangroves, considering leaf micromorphology, this plant is better termed as “mangrove associate” instead of “true mangrove”. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

下肢动脉硬化闭塞症血管成形术的疗效观察

目的:探讨血管成形术治疗下肢动脉硬化闭塞症的临床应用价值。方法:对我院78例下肢动脉硬化闭塞患者的临床资料进行回顾性分析。78例患者(98条血管)术前经CTA诊断后,行腔内血管成形术(PTA)和血管支架植入术治疗,治疗后随访1~18个月,分析踝/肱指数(ABI)、血管内径、皮温及足背动脉搏动的变化。结果:成功完成77例(98.7%)患者、97条(99.0%)患肢的PTA和支架植入术,除1例下肢动脉完全闭塞患者导丝未能成功通过病变导致介入失败外,其余病例经介入治疗后均开通,术中所有病例均未发生血肿、血管壁破裂、穿孔或内支架移位,远端血管血栓栓塞等并发症。术后,患者下肢缺血症状消失或明显减轻,踝/肱指数(ABI)由术前(0.39±0.23)恢复至(0.86±0.26),下肢血管内径及足背动脉搏动均明显改善。结论:PTA和血管支架植入术是一种治疗下肢动脉硬化闭塞症安全有效的方法,成功率高,并发症少,再狭窄率低。     

SARS—CoV N蛋白与病毒mRNA相互作用的初步研究

SARS冠状病毒(SARS-CoV)是一种新型的冠状病毒,其基因组大小约为30,000 nt,为单股正链RNA。病毒基因中的1-72个核甘酸为前导序列。核衣壳(Nucleocapsid,N)蛋白是冠状病毒的主要结构蛋白,它在病毒基因转录,翻译以及病毒颗粒包装中起重要作用。在本研究中,我们通过PCR的方法从SARS-CoV cDNA中克隆N基因,将基因克隆到大肠杆菌表达载体中,经表达纯化获得大量重组蛋白,通过亲和层析和凝胶过滤层析获得高纯度的N蛋白。同时构建前导RNA的转录模板,经体外转录得到地高辛标记的RNA。使用Northwestern分析技术,我们证实纯化的N蛋白在体外可以与RNA发生特异性的结合。N蛋白与病毒RNA的结合特性及其在病毒生活周期中的所起作用的初步研究,为下一步设计出有效的阻断病毒周期从而达到抗病毒目的的药物或疫苗奠定了基础。     

Identity of tendon stem cells – how much do we know?

Tendon stem cells are multi‐potent adult stem cells with broad differentiation plasticity that render them of great importance in cell‐based therapies for the repair of tendons. We called them tendon‐derived stem cells (TDSCs) to indicate the tissue origin from which the stem cells were isolated in vitro. Based on the work of other sources of MSCs and specific work on TDSCs, some properties of TDSCs have been characterized / implicated in vitro. Despite these findings, tendon stem cells remained controversial cells. This was because MSCs residing in different organs, although very similar, were not identical cells. There is evidence of differences in stem cell‐related properties and functions related to tissue origins. Similar to other stem cells, tendon stem cells were identified and characterized in vitro. Their in vivo identities, niche (both anatomical locations and regulators) and roles in tendons were less understood. This review aims to summarize the current evidence of the possible anatomical locations and niche signals regulating the functions of tendon stem cells in vivo. The possible roles of tendon stem cells in tendon healing and non‐healing are presented. Finally, the potential strategies for understanding the in vivo identity of tendon stem cells are discussed.     

The Welfare of Bears in Zoos: A Case Study of Poland

The welfare of captive bears became a big issue of concern in Poland when a case of a bear being ill-treated became a high-profile case in the media. This case created a challenge to verify, study, and understand the main problems associated with bear keeping so that zoos could significantly improve the conditions in which they keep bears or ensure they keep bears at the minimum required standards. The results presented here are from 1 of the few countrywide studies of captive bear conditions conducted in all the captive institutions in Poland that keep bears. Thirteen institutions kept bears at the time of the study (2007–2009), including 54 individuals of 5 species. Major welfare problems were identified, and the results have been used to challenge zoos to address the changes required and focus the government's attention on areas that require legislative improvement.