锥状施克里普藻孢囊的多种形态特征

休眠孢囊是某些甲藻生活史的重要阶段,它被认为是甲藻赤潮爆发的种源。通过观察我国沿海海域采集的锥状施克里普藻（Scrippsiella trochoidea（Stein）Loeblich）休眠孢囊的类型以及形态特征,并将实验条件下形成的休眠孢囊与海区沉积物中休眠孢囊的形态特征进行比较,结果表明,锥状施克里普藻细胞在20°C、12小时光照/12小时黑暗、f/2培养基和f/2-N培养基中分别培养至第14天和第8天,可以观察到休眠孢囊的产生。培养30天后,培养液中有大量休眠孢囊,将藻液避光保存90天后,观察到培养基中有4种类型的休眠孢囊产生：（1）球形到椭球形（长25-39μm）,钙质外壁,稀疏或密被钙质附属物（长1-4μm）;（2）球形（直径为29-35μm）,钙质外壁,附属物非钙质（长0.5-1.5μm）;（3）球形到椭球形（长29-35μm）,钙质,表面光滑,无附属物;（4）球形（直径24-35μm）,有机外壁,无附属物。第1种类型的孢囊最为常见,分别占到2种培养条件下所得全部孢囊的77.70%和95.18%。从沉积物中所得的孢囊多属于第1种类型。分析了实验条件下形成不同类型休眠孢囊的原因和比例,同时探讨了海区沉积物中形成多种孢囊形态特征的原因,为锥状施克里普藻孢囊的生态研究提供了依据。     

锥状施克里普藻孢囊的多种形态特征

休眠孢囊是某些甲藻生活史的重要阶段, 它被认为是甲藻赤潮爆发的种源。通过观察我国沿海海域采集的锥状施克里普藻(Scrippsiella trochoidea (Stein) Loebl ich)休眠孢囊的类型以及形态特征, 并将实验条件下形成的休眠孢囊与海区沉积物中休眠孢囊的形态特征进行比较, 结果表明, 锥状施克里普藻细胞在20°C、12小时光照/12小时黑暗、f/2培养基和f/2-N培养基中分别培养至第14天和第8天, 可以观察到休眠孢囊的产生。培养30天后, 培养液中有大量休眠孢囊, 将藻液避光保存90天后, 观察到培养基中有4种类型的休眠孢囊产生: (1)球形到椭球形(长25-39 μm), 钙质外壁, 稀疏或密被钙质附属物(长1-4 μm); (2)球形(直径为29-35 μm), 钙质外壁, 附属物非钙质(长0.5-1.5 μm); (3) 球形到椭球形(长29-35 μm), 钙质, 表面光滑, 无附属物; (4) 球形(直径24-35 μm ), 有机外壁, 无附属物。第1种类型的孢囊最为常见, 分别占到2种培养条件下所得全部孢囊的77.70%和95.18%。从沉积物中所得的孢囊多属于第1种类型。分析了实验条件下形成不同类型休眠孢囊的原因和比例, 同时探讨了海区沉积物中形成多种孢囊形态特征的原因, 为锥状施克里普藻孢囊的生态研究提供了依据。     

Germination of Azotobacter vinelandii Cysts: Sequence of Macromolecular Synthesis and Nitrogen Fixation

Azotobacter vinelandii cysts undergo conversion to vegetative cells in Burk's nitrogen-free medium utilizing glucose, sucrose, or acetate. In 1% glucose, this overall process was complete in 8 hr and consisted of a germination and an outgrowth phase. Respiration, ribonucleic acid, and protein synthesis began soon after the addition of the germinant, and these processes proceeded at rates characteristic of the germination. The rates of respiration and synthesis increased sharply between 4 and 5 hr, the beginning of the outgrowth, at which time deoxyribonucleic acid synthesis and nitrogen fixation began. Respiration, macromolecular synthesis and nitrogen fixation continued at high rates until the emergence of vegetative cells from the cyst coats.     

Cysts of Azotobacter vinelandii with Double Coats

Cyst germination was studied in cultures of Azotobacter vinelandii ATCC 12837. The existence of cysts enclosed by double coats is described.     

Prevalence of Incidental Pancreatic Cysts on 3 Tesla Magnetic Resonance

Objectives

To ascertain the prevalence of pancreatic cysts detected incidentally on 3-Tesla magnetic resonance imaging (MRI) of the abdomen and correlate this prevalence with patient age and gender; assess the number, location, and size of these lesions, as well as features suspicious for malignancy; and determine the prevalence of incidentally detected dilatation of the main pancreatic duct (MPD).

Methods

Retrospective analysis of 2,678 reports of patients who underwent abdominal MRI between January 2012 and June 2013. Patients with a known history of pancreatic conditions or surgery were excluded, and the remaining 2,583 reports were examined for the presence of pancreatic cysts, which was then correlated with patient age and gender. We also assessed whether cysts were solitary or multiple, as well as their location within the pancreatic parenchyma, size, and features suspicious for malignancy. Finally, we calculated the prevalence of incidental MPD dilatation, defined as MPD diameter ≥ 2.5 mm.

Results

Pancreatic cysts were detected incidentally in 9.3% of patients (239/2,583). The prevalence of pancreatic cysts increased significantly with age (p<0.0001). There were no significant differences in prevalence between men and women (p=0.588). Most cysts were multiple (57.3%), distributed diffusely throughout the pancreas (41.8%), and 5 mm or larger (81.6%). In 12.1% of cases, cysts exhibited features suspicious for malignancy. Overall, 2.7% of subjects exhibited incidental MPD dilatation.

Conclusions

In this sample, the prevalence of pancreatic cysts detected incidentally on 3T MRI of the abdomen was 9.3%. Prevalence increased with age and was not associated with gender. The majority of cysts were multiple, diffusely distributed through the pancreatic parenchyma, and ≥ 5 mm in size; 12.1% were suspicious for malignancy. An estimated 2.7% of subjects had a dilated MPD.     

棉花种子萌发过程中子叶蛋白体变化

对棉花种子萌发过程中子叶细胞内蛋白体的变化进行了详细的观察。干种子内存在仅由蛋白质基质组成无内含物的蛋白体,含有球状晶体的蛋白体和无含球状晶体和拟晶体的蛋白体。种子萌发过程中蛋白体逐渐液泡化,其降解方式可分为三种类型：（１）内部降解类型：（２）周边降解类型;（３）内部和周边同时降解类型。文中还一步进行了不同降解类型与酶的分布,蛋白体存在部位和萌发时间进程之间的关系。     

Comparative Outcomes of the Two Types of Sacral Extradural Spinal Meningeal Cysts Using Different Operation Methods: A Prospective Clinical Study

This prospective study compares different clinical characteristics and outcomes of patients with two types of sacral extradural spinal meningeal cysts (SESMC) undergoing different means of surgical excision. Using the relationship between the cysts and spinal nerve roots fibers (SNRF) as seen under microscope, SESMCs were divided into two types: cysts with SNRF known as Tarlov cysts and cysts without. The surgical methods were tailored to the different types of SESMCs. The improved Japanese Orthopedic Association (IJOA) scoring system was used to evaluate preoperative and postoperative neurological function of the patients. Preoperative IJOA scores were 18.5±1.73, and postoperative IJOA scores were 19.6±0.78. The difference between preoperative and postoperative IJOA scores was statistically significant (t = -4.52, p = 0.0001), with a significant improvement in neurological function after surgery. Among the improvements in neurological functions, the most significant was sensation (z=-2.74, p=0.006), followed by bowel/bladder function (z=-2.50, p=0.01). There was a statistically significant association between the types of SESMC and the number (F=12.57, p=0.001) and maximum diameter (F=8.08, p=0.006) of the cysts. SESMC with SNRF are often multiple and small, while cysts without SNRF tend to be solitary and large. We advocate early surgical intervention for symptomatic SESMCs in view of significant clinical improvement postoperatively.     

Scanning electron microscopic studies on the external morphology of Azotobacter vinelandii during encystment and germination.

Aspects of the external morphology of Azotobacter vinelandii cells during encystment and germination processes were observed with scanning electron microscopy. Most of the vegetative cells have a smooth surface but some have warty surfaces. The intact cysts have wrinkled surfaces and occasional small heaves. Mucoid materials are present on the surface of the cysts. During the encystment process, an extensive peeling-off of coat materials was noted, then the excretion and aggregation of new capsular materials was immediately followed. The germination process was initiated by an expansion of the central body (the cell), then the emerging of this cell from the cyst coats was observed.     

CONTROL OF GERMINATION OF ALEXANDRIUM TAMARENSE (DINOPHYCEAE) CYSTS FROM THE LOWER ST. LAWRENCE ESTUARY (CANADA)

Cysts of the toxic dinoflagellate Alexandrium tamarense (Lebour) Balech 1992 from the lower St. Lawrence estuary were used in a test of the following hypotheses: (1) cyst germination is triggered by a change in temperature, and (2) germination rate varies throughout the year and is controlled by a circannual internal biological clock. Results show that cyst germination was not affected significantly by temperature of incubation over the range 1°–16° C, and light showed no significant stimulation of germination. This is supported by the lack of effect of cyst incubation conditions during evaluation of the seasonal changes in germination rate (two temperatures: 4° and 15° C, and two light conditions: darkness and 150 μmol photons·m^?2·s^?1). Thus, direct environmental control through short-term increases in temperature and exposure to light has no effect on the germination of the cysts tested. The rate of germination, observed monthly over a 16-month period, showed low germination (<20%) over most of the period tested, except for a maximum reaching more than 50% germination in August to October of the second year of the experiment. This pattern was observed for cysts both from monthly field collections and from laboratory-stored cysts kept under constant environmental conditions (4° C, in the dark). The peak in germination observed under constant environmental conditions (in the laboratory), the almost coincidental increase in cyst germination observed for the field-collected cysts, and the absence of effects of temperature and light during incubation could be explained either by a temperature-controlled cyst maturation period (the time-temperature hypothesis of Huber and Nipkow 1923) or by the presence of an internal biological clock. However, the large decline in the rate of germination 2 months after the maximum provides strong support for the biological clock hypothesis. The ca. 12-month maturation (dormancy) period observed for the laboratory-stored cysts is the longest reported for this species to our knowledge; this might be related to the low storage temperature (4° C), which is close to bottom temperatures generally encountered in this environment (0° to 6° C). Similar field and laboratory storage temperatures could explain the coincidental increase in germination rate in the fall of the second year if cyst maturation is controlled by temperature. A fraction of the laboratory-stored cysts did not follow a rhythmic pattern: A rather constant germination rate of about 20% was observed throughout the year. This continuous germination of likely mature cysts may supplement the local blooms of this toxic dinoflagellate, as these often occur earlier than peak germination observed in late summer. It seems that two cyst germination strategies are present in the St. Lawrence: continuous germination after cyst maturation, with temperature controlling the length of the maturation period, and germination controlled by a circannual internal rhythm.     

Infection of Acanthamoeba polyphaga with Simkania negevensis and S. negevensis Survival within Amoebal Cysts

Simkania negevensis, a novel microorganism belonging to the family Simkaniaceae in the order Chlamydiales, has an intracellular developmental cycle during which two morphological entities, elementary bodies (EB) and reticulate bodies (RB), are seen by electron microscopy. Rates of seropositivity to the organism are high in certain population groups, and S. negevensis has been associated with respiratory illness in humans. This study reports for the first time the ability of S. negevensis to survive and grow inside Acanthamoeba polyphaga in addition to its known ability to grow in cell cultures of human or simian origin. Infectivity of S. negevensis and growth in amoebae were monitored by immunoperoxidase assays. Long-term persistence and exponential growth of S. negevensis in amoebal trophozoites were demonstrated by infectivity assays and by electron microscopy. EB and dividing RB of S. negevensis were observed within inclusion bodies inside A. polyphaga. When S. negevensis-infected A. polyphaga amoebae were exposed to adverse conditions resulting in encystation of the amoebae, several possible outcomes were observed: cysts containing both normal amoebic cytoplasm and S. negevensis; cysts in which S. negevensis cells were relegated to the space between cyst walls; and cysts containing S. negevensis, but apparently lacking amoebal cytoplasm. S. negevensis within dried amoebal cysts was capable of long-term survival. The possibility that amoebae may have a role in natural transmission of S. negevensis needs to be investigated.     

Morphology of the cyst of Giardia microti by light and electron microscopy

Cysts of Giardia microti, isolated from feces and intestinal contents of Microtus ochrogaster, were examined by light and electron microscopy. These cysts differed morphologically from cysts of other G. duodenalis morphological types in that these cysts often contained two apparently differentiated trophozoites with mature ventral discs. Cysts more closely resembling those reported for G. lamblia and G. muris were in greater abundance in preparations made from intestinal contents and were interpreted as immature cysts. "Multiple fission" cysts, reported in G. muris and G. microti by earlier workers, were not observed; however, endosymbiotic bacteria were found in the cysts of G. microti and may have been responsible for reports of multiple fission in the cysts of Giardia.     

Characterization of the central body of theAzotobacter cyst

Filar micrometer measurements of the central body during its conversion to the vegetative cell indicated an initial spherical body of about 1.7 microns in diameter. The central body first increases in diameter then elongates such that its length is 2–2.5 times the diameter. Central bodies supplemented with casein hydrolysate in addition to sucrose formed vegetative cells in only 8 hr instead of the usual 12. Central bodies were quite susceptible to lysis by EDTA-lysozyme or citrate-lysozyme, but relatively insensitive to citrate-EDTA or single employment of EDTA or citrate. Comparative electron microscopy of cysts and central bodies following sonication revealed little alteration in cysts but reduction of central bodies to cellular debris after only 2 min. Central bodies were resistant to bacteriophage adsorption at 0 hr and required about 4 hr incubation before adsorption could occur.This work was supported by U.S.Public Health Service grant AI-05551 from the National Institute of Allergy and Infectious Diseases. Bacteriophage A-22 was kindly provided by Dr. O. Wyss, University of Texas, Austin.     

Morphology and Round Body Formation in Vibrio marinus

The morphology of Vibrio marinus MP-1 was studied by phase and electron microscopy. The ultrastructure of the vibrio form of V. marinus was found to be typically gram-negative with a trilaminar plasma membrane and cell wall. The coccoid or round bodies noted in otherwise pure cultures of V. marinus were frequently found in early and late stationary phase of growth. The round bodies in ultrathin section were found to contain at least one, and often three or four, cell units. Three types of round bodies were observed in ultrathin section, each differing in size and behavior: "spherules," "spheres" or the "round body," and "giant cells" or "macrospheres." The round bodies appeared to be associated with, or to result from, the constrictive cell division of V. marinus.     

Incidence of Spinal Perineurial (Tarlov) Cysts among East-European Patients

The spinal perineurial cyst (Tarlov) is a dilatation between the perineurium and endoneurium of spinal nerve roots, located at level of the spinal ganglion and filled with cerebrospinal fluid but without communication with the perineurial subarachnoid space. The aim of the study was to evaluate it incidence among East-European patients. The retrospective data collected during various magnetic resonance spinal examinations and stored on the picture archiving and communication system was analyzed for an incidence of perineurial cysts. From among 842 patients that underwent examination, 75 cases perineurial cysts were revealed. In 22 cases single anomalies were found. In remaining 53 cases, multiple uni- or less frequently bilateral changes were noted. The most common position was the sacral canal, particularly the level of S2 and S3. Occasionally, cysts were also visible on the cervical, thoracic and lumbar level. Incidence of sacral perineurial cysts was significantly higher in females than in males. Similar data was found for single and multiple changes despite of their localization. Insignificant changes were seen for patient age and cyst size. Perineurial spinal cysts were the most frequently observed on the sacral level and such changes were more common in females.     

Cytology of lepidoptera. III. Giant cysts: A morphological trait of apyrene spermatogenesis in an Ephestia kuehniella strain

A comparative investigation of testicular eupyrene cysts (in larvae) and apyrene cysts (in pupae) of Ephestia kuehniella laboratory strains was conducted using light and electron microscopy. Eupyrene cysts in the first meiotic division contained 64 spermatocytes, which showed only moderate asynchrony. In one of the strains, a wild-type strain, L, normal-sized cysts occurred together with abnormally large cysts. These are called giant cysts in this article. One of the premeiotic cysts, early giant cysts, studied in detail, contained approximately a fourfold number of cells compared with the number in a eupyrene cyst of the same stage. In cysts harboring spermatocytes and spermatids, late giant cysts, cell differentiation was highly asynchronous. Failure in one of two control mechanisms in early cyst development may have caused the appearance of the cysts. Control of cell division might have been sloppy in apyrene spermatogonia. Hence, the spermatogonia within the cyst could have passed through additional division cycles. Alternatively, the giant cysts may have originated from more than one predefinitive gonial cell enclosed in a common envelope of sheath cells. As a third possibility, giant cysts could have arisen by fusion of normal cysts at a later stage. In either case, this is evidence that separation of eupyrene and apyrene pathways is earlier than was previously expected. In two other Ephestia strains, apyrene sperm development proceeded without formation of giant cysts. One was a mutant strain, a, and the other one was a recently established wild-type strain, Sbr. Apyrene sperm development is considered an example of degenerate evolution in which enhanced variability between species and even between populations of one species is a common phenomenon.     

The life cycle of Gyrodinium instriatum (Dinophyceae) in culture*

The life cycle events of an unarmored dinoflagellate Gyrodinium instriatum Freudenthal et Lee has been investigated using clonal cultures. After the inoculation of vegetative cells into fresh medium, clumping of gametes was observed after a period of 10 days. In the clumps, a number of gametes were observed to be swimming in close contact with each other, pairing successively and then forming a plano-zygote. This clumping behavior is considered to be useful in the performance of sexual reproduction, particularly in the event of low cell density, because it increases the chance of fusion. Gametes of this species were most often isogarnous, although apparent amsogamous fusions were occasionally observed. When planozygotes were isolated and placed in fresh medium, they enlarged their size and finally divided into two cells. The daughter cells continued to multiply by binary fission and produced vegetative cells. Thus, G. instriatum has an alternative cycle between vegetative cells and zygotes without a hypnozygote stage. However, cysts of this species were transformed from large motile cells (pre-cyst cells) which are oblong and dorso-ventrally flattened in shape. These mottle pre-cyst cells have two longitudinal flagella, which may indicate that cysts of this species are of zygote origin. On the basis of these results, the relationship between zygotes and pre-cysts of G. instriatum is discussed. Excystment was enhanced by dark and cold treatments prior to the incubation for germination experiments with a germination success rate of 26–64%. Encystment was greatly inhibited by the lack of dark and cold treatments.     

Changes in Ultrastructure and Subunit Composition of Protein Body in Rice Endosperm during Germination

Changes in ultrastructure of protein bodies in subaleurone cells of rice endosperm during germination were studied by transmission electron microscopy. The subaleurone cells contained two different types of protein bodies: PB-I (spherical) and PB-II (crystalline). Both types of protein bodies were deconstructed during germination. But there was a considerable difference in digestibility between PB-I and PB-II. PB-II which did not have a dense core was easily digested from the central portion when germination began. At 6 days of germination, PB-II was almost deconstructed. On the other hand, PB-I which displayed concentric rings with a dense core was digested from the outside after 3 days of germination. At 9 days of germination, many kernels of the spherical protein bodies remained.

Changes in subunit composition of protein bodies during germination were investigated by SDS-polyacrylamide gel electrophoresis. Protein body fractions were isolated from germinating grains at various stages by enzymatic digestion and two-phase system, then subjected to SDS-polyacrylamide gel. As germination proceeded, 15 (b₁), 20 (d₁), 24 (e), 35 (f₁) and 37 (f₃) kdaltons subunits decreased. On the other hand, 16 (b₂), 21 (d₂) and 36 (f₂) k daltons subunits remained at the later stage of germination. We think that PB-I contains b₂, d₂ and f₂ subunits and is attacked only from the outside at middle and later stages of germination by de novo protease. On the contrary, PB-II contains b₁ d₁ e, f₁ and f₃ subunits is utilized at an early stage of germination. PB-II may possibly contain latent protease. The breakdown process of PB-I was by exo-type digestion, on the contrary, that of PB-II was by endo-type digestion.     

Use of enlarged cells and nuclei for studying mitosis inNeurospora

Summary Mitotic division stages studied by light microscopy in differentNeurospora crassa cell types clearly resemble prophase, metaphase, anaphase, and telophase stages of higher eukaryotes. 1. When conidia are cultured in liquid medium containing 3.22 M ethylene glycol, they grow without cell division, forming giant spheres with multiple nuclei. In a few giant cells, nuclear numbers remain small (1 to 3) but the nuclei become very large. Seven large chromosomes are seen in some nuclei suggesting polyteny, 14 or more chromosomes are seen in other, very large nuclei, indicating polyploidy. Cell volume and nuclear volume are positively correlated in giant cells. Nuclear divisions are not synchronous within individual multinucleate giant cells. 2. Nuclear division stages were also observed in crosses heterozygous for the dominant mutant banana where haploid prefusion nuclei in late-forming croziers revert to mitosis. Swollen ascogenous hyphae become highly multinucleate after several rounds of mitosis. Mitosis is completely synchronous in nuclei of the same crozier cyst, providing replicate information for unambiguous identification of division stage. 3. Observations are also reported of mitosis in a cell-wall deficient slime strain. Previous observations on mitosis in large nuclei of the ascus are summarized for comparison. The nucleolus persists throughout mitosis in the giant cells, multinucleate reverted croziers, and in the cell-wall deficient slime strain. It is expelled from the dividing nuclei in the ascus. Spindles and spindle pole bodies, which are normally conspicuous in asci, are also seen in normal and reverted croziers, but they have not been clearly identified in the ethylene glycol-induced giant cells.     

番茄种子及萌发过程中蛋白体超微结构的研究

对番茄种子蛋白体的结构,类型及萌发过程中的变化进行了详细观察,未萌发种子蛋白体周围由一单层膜包裹,内部为蛋白质基质及分布其中的内含物３部分组成,根据内含物形态和性质上的不同可分为球状晶体,拟晶体和簇晶体３种形式,根据蛋白体所含内含物的不同,将蛋白体划分为５种基本类型：（１）基质蛋白体;（２）球状晶体蛋白体;（３）拟晶体蛋白体;（４）簇晶体蛋白体;（５）复合蛋白体。萌发过程中,蛋白体逐渐降解并液泡化     

Oxygen Uptake In Cysts and Trophozoites of Giardia Lamblia

ABSTRACT. Oxygen uptake in cysts and trophozoites of the parasitic protozoan Giardia lamblia was examined. Both showed oxygen uptake activity, but that of cysts was only 10% to 20% that of trophozoites. Oxygen dependence of oxygen uptake in cysts and trophozoites showed oxygen maxima above which oxygen uptake decreased. the oxygen concentration at which the oxygen uptake rate was greatest was higher for trophozoites than for cysts. the effect of various inhibitors on cyst and trophozoithe oxygen uptake suggested that flavoproteins and quinones play some role in oxygen uptake. the substrate specificities and the effect of inhibitors on G. lamblia trophozoites were similar to those observed for G. muris. Metronidazole, the drug most commonly used in treatment of giardiasis, inhibited oxygen uptake and motility in trophozoites; however, it had no obvious effect on either oxygen uptake or excystation in cysts. Menadione, a redox cycling naphthaquinone, first stimulated, then completely inhibited, oxygen uptake in cysts and trophozoites; a complete loss of cyst viability and trophozoite motility was also observed. the effect of menadione on G. Iamblia may indicate that redox cycling compounds have potential as chemotherapeutic agents for the treatment of giardiasis.