Avian Cerebellar Floccular Fossa Size Is Not a Proxy for Flying Ability in Birds

Extinct animal behavior has often been inferred from qualitative assessments of relative brain region size in fossil endocranial casts. For instance, flight capability in pterosaurs and early birds has been inferred from the relative size of the cerebellar flocculus, which in life protrudes from the lateral surface of the cerebellum. A primary role of the flocculus is to integrate sensory information about head rotation and translation to stabilize visual gaze via the vestibulo-occular reflex (VOR). Because gaze stabilization is a critical aspect of flight, some authors have suggested that the flocculus is enlarged in flying species. Whether this can be further extended to a floccular expansion in highly maneuverable flying species or floccular reduction in flightless species is unknown. Here, we used micro computed-tomography to reconstruct “virtual” endocranial casts of 60 extant bird species, to extract the same level of anatomical information offered by fossils. Volumes of the floccular fossa and entire brain cavity were measured and these values correlated with four indices of flying behavior. Although a weak positive relationship was found between floccular fossa size and brachial index, no significant relationship was found between floccular fossa size and any other flight mode classification. These findings could be the result of the bony endocranium inaccurately reflecting the size of the neural flocculus, but might also reflect the importance of the flocculus for all modes of locomotion in birds. We therefore conclude that the relative size of the flocculus of endocranial casts is an unreliable predictor of locomotor behavior in extinct birds, and probably also pterosaurs and non-avian dinosaurs.     

Visualization of layers lining the lung of the South American lungfish (Lepidosiren paradoxa) and a comparison with the frog and rat.

Comarisons have been made of the structure of layers lining the lungs of lungfish, frog and rat using material fixed by perfusion of the pulmonary circulation of physiological pressures and at normal air pressures within the lung. The lining consists of a thin densely osmiophilic surface layer which covers a much thicker hypophase of generally floccular appearance. Tubular myelin, present in the frog and rat lung lining, was not observed in the layers lining the lung of Lepidosiren.     

Ultrastructure of the endolymphatic sac in the larva of the Japanese red-bellied newt Cynops pyrrhogaster

The ultrastructure of the endolymphatic sac (ES) of the late stage larva of the Japanese red-bellied newt, Cynops pyrrhogaster (stage 57), was examined by light and transmission electron microscopy. The two endolymphatic sacs are located at the dorsal-medial side of the otic vesicle on the dorsal-lateral side of the midbrain in the cranial cavity. The wall of the sac is composed of a layer of cubical epithelial cells with loose, interposed intercellular spaces. The sac contains a large luminal cavity, in which endolymph and numerous otoconia are present. The epithelial cells of different portions of the sac have a similar structure. These cells contain an abundance of cytoplasmic organelles, including ribosomes, Golgi complexes, and numerous vesicles. Two types of vesicles are found in the epithelial cells: the “floccular” vesicle and the “granular” vesicle. The floccular vesicles are located in the supra- and lateral-nuclear cytoplasm and contain flocccular material. The granular vesicles have a fine granular substance and are usually situated apposed to the apical cell membrane. The granular vesicles are suggested to be secreted into the lumen, while the floccular vesicles are thought to be absorbed from the lumen and conveyed to the intercellular spaces by the epithelial cells. The apical surfaces of the epithelial cells bear numerous microvilli. Apparently floating cells, which bear long microvilli on the free surfaces, are observed in the lumen of the ES. Based on the fine structure, the function of the endolymphatic sac of the newt Cynops pyrrhogaster is discussed.     

Glycogen metabolism in the prelaid chick embryo.

Glycogen metabolism has been studied during the development of the early chick embryo, at the cytochemical and ultrastructural levels. Two waves of glycogen synthesis and breakdown have been found. In the first, free clusters of glycogen particles are synthesized at late oogenesis. These clusters are found later in invaginations of the membrane of vesicles containing a floccular material (FLOV). The glycogen clusters are degraded there during ovulation and the first hours in the oviduct. The second wave of glycogen synthesis begins before cleavage, reaching a maximum at mid-uterine age. This second wave occurs in another type of vesicle (GLYV), which eventually disintegrates releasing free clusters of glycogen granules. This glycogen is degraded in membranous structures containing a floccular material, as in the first wave of degradation. The degradation ends at the late uterine stages, and at the same time numerous ribosomes are formed. This period corresponds to area pellucida formation, which probably depends on the energy liberated during the second wave of glycogen degradation.     

Specific Biological Traits of Males of the Blue Crab Paralithodes platypusin the Northeast Part of the Sea of Okhotsk

Data on body size, composition, and mass; peculiarities of molting; and number and seasonal migrations of males of the blue king crab Paralithodes platypusfrom the northeast part of the Sea of Okhotsk are presented. It was found that the main aggregations of juveniles (up to 65% of the total number) are located in the south of the population area. Males molt once every two years, and the relative number of groups molting in alterating years was equal. Mass molting was observed at the end of June and July. Mass migration of males to shoals occurred in June, and their return occurred in October.     

Depression of the vestibulo-ocular and optokinetic responses by intrafloccular microinjection of GABA-A and GABA-B agonists in the rabbit

The functional implication of the cerebellar flocculus in regulation of the VOR and OKR gain has mostly been studied by lesion experiments, and the hypotheses derived from these experiments are not always in line with one another. In the present study, a reversible method was used to inhibit floccular Purkinje cells. The GABA-A agonist muscimol or the GABA-B agonist baclofen were bilaterally injected into the flocculus of rabbits, and the effects of these injections on the gain of the VOR and OKR were studied. Both drugs induced a reduction by at least 50% of the gain of the VOR in light and darkness, and of the OKR. Although GABA-A and GABA-B receptors are known to have different cerebellar localizations, muscimol and baclofen injections resulted in quantitatively similar effects. It is suggested that these GABA-agonists cause either direct or indirect inhibition of floccular Purkinje cells, thus reducing modulation of the firing rate of these neurons by afferent mossy and climbing fibers. Because the flocular Purkinje cells act out of phase with the vestibular neurons which drive the oculomotor neurons, a reduced output of floccular Purkinje cells would result in a reduction of the VOR and OKR gain. These experiments provide strong evidence that the cerebellar flocculus has a positive influence on the basic VOR and OKR gain.     

Dynamics of microbial community structure of and enhanced biological phosphorus removal by aerobic granules cultivated on propionate or acetate

Aerobic granules are dense microbial aggregates with the potential to replace floccular sludge for the treatment of wastewaters. In bubble-column sequencing batch reactors, distinct microbial populations dominated propionate- and acetate-cultivated aerobic granules after 50 days of reactor operation when only carbon removal was detected. Propionate granules were dominated by Zoogloea (40%), Acidovorax, and Thiothrix, whereas acetate granules were mainly dominated by Thiothrix (60%). Thereafter, an exponential increase in enhanced biological phosphorus removal (EBPR) activity was observed in the propionate granules, but a linear and erratic increase was detected in the acetate ones. Besides Accumulibacter and Competibacter, other bacterial populations found in both granules were associated with Chloroflexus and Acidovorax. The EBPR activity in the propionate granules was high and stable, whereas EBPR in the acetate granules was erratic throughout the study and suffered from a deterioration period that could be readily reversed by inducing hydrolysis of polyphosphate in presumably saturated Accumulibacter cells. Using a new ppk1 gene-based dual terminal-restriction fragment length polymorphism (T-RFLP) approach revealed that Accumulibacter diversity was highest in the floccular sludge inoculum but that when granules were formed, propionate readily favored the dominance of Accumulibacter type IIA. In contrast, acetate granules exhibited transient shifts between type I and type II before the granules were dominated by Accumulibacter type IIA. However, ppk1 gene sequences from acetate granules clustered separately from those of propionate granules. Our data indicate that the mere presence of Accumulibacter is not enough to have consistently high EBPR but that the type of Accumulibacter determines the robustness of the phosphate removal process.     

Floccular complex spike response to transparent retinal slip.

The flocculus of the rabbit is involved in the plasticity of compensatory eye movements. It is generally assumed that the climbing fiber input to floccular Purkinje cells encodes "retinal slip," which in turn would be a measure for the oculomotor performance error. To test this, we used transparent motion stimuli, creating a retinal slip signal that broke up this relation. We recorded the ensuing oculomotor behavior and complex spike activity of floccular Purkinje cells. Complex spike modulation in response to transparent stimulation was identical to that of a single optokinetic pattern, despite considerably different retinal slip. These results suggest that the climbing fiber code may be effectively related to the eye movement performance error, rather than to retinal slip.     

Determination of the extraction kinetics for the quantification of polyhydroxyalkanoate monomers in mixed microbial systems

For the first time, a systematic approach was conducted to determine the key factors influencing the kinetics of hydroxyalkanote (HA) extraction in biological systems. Six mixed microbial systems where polyhydroxyalkanoate (PHA) is produced were evaluated. Experiments were carried out for full-scale and lab-scale activated sludge systems using different configurations (containing floccular or granular sludge), as well as specific PHA accumulating cultures that contain high or low intracellular PHA fractions. The overall reaction was limited by the kinetics of the PHA hydrolysis in floccular cultures, whereas in granular cultures, it was limited by the cell lysis step. The monomeric composition of the polymer also had an impact on the HA extraction rate: higher acid concentration and a longer digestion time should be employed when cells accumulate monomers with more substituents, such as hydroxy-2-methylbutyrate (H2MB) and hydroxy-2-methylvalerate (H2MV). This study optimised the method for HA extraction, which impacts the assessment of the quantity and quality of PHA biopolymers.     

Ultrastructural Features of Host-Parasite Relationship in Oral Candidiasis

In oral candidiasis, many keratinized epithelial cells and cells of Candida albicans are shed. Scales from patients with oral candidiasis were used for electron microscopic study of the epithelial-fungal relationship. Scales, scraped from the tongue and oral mucosa, were fixed for fungi. Electron microscopic observations showed cells of C. albicans outside, penetrating, or within the epithelial cells. Extracellular fungi possessed a floccular material adherent to the outer surface of the cell wall. Intracellular fungi lacked the floccular material which appeared to detach as fungi invaded the epithelial cells. Large vacuoles, which sometimes contained myelin figures, occupied the cytoplasm of fungal cells. Epithelial cells frequently contained several fungi. Discontinuous plasma membranes marked sites of fungal entry. Cytoplasmic areas devoid of fungi showed many tonofibrils, but the cytoplasm adjacent to fungi often lacked tonofibrils. Micrographs suggested that fungal cells lysed the tonofibrils. Bacteria were abundant in the scrapings, but always occupied an extracellular position.     

Evidence for bacteriophage activity causing community and performance changes in a phosphorus-removal activated sludge

Bacteria are known to play important roles in biogeochemical cycles and biotechnology processes, but little is known about the influence of bacteriophage on these processes. A major impediment to the study of host-bacteriophage interactions is that the bacteria and their bacteriophage are often not available in a pure culture. In this study, we detected an unexpected decline in the phosphorus-removal performance of a granular laboratory-scale wastewater treatment reactor. Investigations by FISH, transmission electron microscopy and proteomics led us to hypothesize that a bacteriophage infection of the uncultured Candidatus 'Accumulibacter phosphatis' was responsible for the decline in performance. Further experiments demonstrated that the addition of a putative bacteriophage-rich supernatant, obtained from the previous failed reactor to phosphorus-removal reactors, caused a decrease in the abundance of Accumulibacter in both granular and floccular activated sludges. This coincided with increases in bacteriophage-like particles and declining phosphorus-removal performance. The granular sludge did not recover after the attack, but the floccular sludge regained Accumulibacter numbers and phosphorus-removal performance. These findings suggest that bacteriophage may play a significant role in determining the structure and function of bacterial communities in activated sludges.     

Migrations of Fish in Lake Glubokoе

Daily and seasonal cyclicity, directivity, and area of the fish migration in the main ecological zones of Lake Glubokoe have been revealed with the help of hydroacoustic complexes. Mass appearance of fish in the epipelagial and profundal of the water body is observed at dusk and at night, and they return to the littoral and sublittoral with the dawn. In the summer, vertical migrations of fish occur mainly in the near-surface layers of the water column, and the fish also occupy the profundal in late autumn.     

Uptake of tritiated uteroglobin by the endometrium of the rabbit during peri-implantation

Summary Uteroglobin, labelled with N-succinimidyl-(2–3³H)-propionate, was applied in vivo for 3 h to pregnant rabbit uteri 7 and 9 days after mating. Light- and electronmicroscopic autoradiographs showed that the endometrial epithelium, both ciliated and non-ciliated cells, is able to take up³H-uteroglobin, however, with differing intensity. Large areas of labelling were found in the luminal epithelium, whereas the glandular epithelium contained fewer silver grains. Moreover, intensively labelled single cells or symplasms occurred in both luminal and glandular epithelium. They were identified as degenerating or dead cells. After internalization by pinocytosis or phagocytosis, the tritiated uteroglobin was observed in multivesicular bodies or in lysosomes with floccular content. Later, radioactivity was either found within residual bodies or distributed throughout the entire epithelium and the subepithelial stroma, i.e., the silver grains could no longer be assigned to specific cell organelles.     

Mass mortality of Sardinella aurita Valenciennes (Pisces, Clupeidae) in Thessaloniki Bay (Macedonia, Greece)

Mass mortality of Sardinella aurita was observed in Thessaloniki Bay during an abrupt temperature fall in February 1991. The mass of dead fish was estimated to be about 79.4 tonnes.     

4-Aminopyridine Does Not Enhance Flocculus Function in Tottering,a Mouse Model of Vestibulocerebellar Dysfunction and Ataxia

The potassium channel antagonist 4-aminopyridine (4-AP) improves a variety of motor abnormalities associated with disorders of the cerebellum. The most rigorous quantitative data relate to 4-AP''s ability to improve eye movement deficits in humans referable to dysfunction of the cerebellar flocculus. Largely based on work in the ataxic mouse mutant tottering (which carries a mutation of the Cacna1a gene of the P/Q voltage-activated calcium channel), 4-AP is hypothesized to function by enhancing excitability or rhythmicity of floccular Purkinje cells. We tested this hypothesis by determining whether systemic or intrafloccular administration of 4-AP would ameliorate the eye movement deficits in tottering that are attributable to flocculus dysfunction, including the reductions in amplitude of the yaw-axis vestibulo-ocular reflex (VOR) and vision-enhanced vestibulo-ocular reflex (VVOR), and the optokinetic reflex (OKR) about yaw and roll axes. Because tottering''s deficits increase with age, both young and elderly mutants were tested to detect any age-dependent 4-AP effects. 4-AP failed to improve VOR, VVOR, and OKR gains during sinusoidal stimuli, although it may have reduced the tendency of the mutants'' responses to VOR and VVOR to decline over the course of a one-hour recording session. For constant-velocity optokinetic stimuli, 4-AP generated some enhancement of yaw OKR and upward-directed roll OKR, but the effects were also seen in normal C57BL/6 controls, and thus do not represent a specific reversal of the electrophysiological consequences of the tottering mutation. Data support a possible extra-floccular locus for the effects of 4-AP on habituation and roll OKR. Unilateral intrafloccular 4-AP injections did not affect ocular motility, except to generate mild eye elevations, consistent with reduced floccular output. Because 4-AP did not produce the effects expected if it normalized outputs of floccular Purkinje cells, there is a need for further studies to elucidate the drug''s mechanism of action on cerebellar motor dysfunction.     

Microbial dynamics in anaerobic enrichment cultures degrading di-n-butyl phthalic acid ester

Although anaerobic biodegradation of di-n-butyl phthalic acid ester (DBP) has been studied over the past decade, only little is known about the microorganisms involved in the biological anaerobic degradation pathways. The aim of this work is to characterize the microbial community dynamics in enrichment cultures degrading phthalic acid esters under methanogenic conditions. A selection pressure was applied by adding DBP at 10 and 200 mg L(-1) in semi-continuous anaerobic reactors. The microbial dynamics were monitored using single strand conformation polymorphism (SSCP). While only limited abiotic losses were observed in the sterile controls (20-22%), substantial DBP biodegradation was found in the enrichment cultures (90-99%). In addition, significant population changes were observed. The dominant bacterial species in the DBP-degrading cultures was affiliated to Soehngenia saccharolytica, a microorganism described previously as an anaerobic benzaldehyde degrader. Within the archaeal community, there was a shift between two different species of the genus Methanosaeta sp., indicating a highly specific impact of DBP or degradation products on archaeal species. RNA-directed probes were designed from SSCP sequences, and FISH observations confirmed the dominance of S. saccharolytica, and indicated floccular microstructures, likely providing favourable conditions for DBP degradation.     

The evolutionary significance of mass extinctions

Local extinctions of populations, species or groups of species in a particular area are commonly observed by biologists. There are also historical records of the total extinction of single species such as the Dodo, the Great Auk and the Tasmanian Wolf. Mass extinctions are on a much larger scale, and their study is based on the fossil record. The aims of this review are to explore the nature of mass extinctions and their evolutionary significance. The key questions are: what is mass extinction, what are the causes of mass extinctions, do mass extinctions follow a regular pattern, and how do mass extinctions affect our understanding of evolutionary processes?     

Metagenomic and metaproteomic analyses of Accumulibacter phosphatis‐enriched floccular and granular biofilm

Biofilms are ubiquitous in nature, forming diverse adherent microbial communities that perform a plethora of functions. Here we operated two laboratory‐scale sequencing batch reactors enriched with Candidatus Accumulibacter phosphatis (Accumulibacter) performing enhanced biological phosphorus removal. Reactors formed two distinct biofilms, one floccular biofilm, consisting of small, loose, microbial aggregates, and one granular biofilm, forming larger, dense, spherical aggregates. Using metagenomic and metaproteomic methods, we investigated the proteomic differences between these two biofilm communities, identifying a total of 2022 unique proteins. To understand biofilm differences, we compared protein abundances that were statistically enriched in both biofilm states. Floccular biofilms were enriched with pathogenic secretion systems suggesting a highly competitive microbial community. Comparatively, granular biofilms revealed a high‐stress environment with evidence of nutrient starvation, phage predation pressure, and increased extracellular polymeric substance and cell lysis. Granular biofilms were enriched in outer membrane transport proteins to scavenge the extracellular milieu for amino acids and other metabolites, likely released through cell lysis, to supplement metabolic pathways. This study provides the first detailed proteomic comparison between Accumulibacter‐enriched floccular and granular biofilm communities, proposes a conceptual model for the granule biofilm, and offers novel insights into granule biofilm formation and stability.     

N-乙酰半胱氨酸改善大鼠心肌梗死后心室结构重塑的研究

目的：探讨N-乙酰半胱氨酸（N-acetylcysteine,NAC）对大鼠心肌梗死（myocardial infarction,MI）后心室结构重塑的影响及其潜在机制。方法：Sprague-Dawley（SD）大鼠96只,随机分为空白对照组（blank control,BC组）6只,余90只制作心肌梗死模型,成功存活24小时后随机分为NAC干预组（NAC）34只,生理盐水对照组（NS）32只,NAC组腹腔注射NAC[0.2 mg·kg-1.2d-1],NS组腹腔注射同等剂量的生理盐水。连续干预4周后,超声心动图检测大鼠收缩期左室后壁厚度（systolic left ventricular posterior wallthickness,LVPW;s）,舒张期左室后壁厚度（diastolic left ventricular posterior wall thickness,LVPW;d）,收缩期室间隔厚度（systolicinterventricular septal thickness,IVS;s）,舒张期室间隔厚度（diastolic interventricular septal thickness,IVS;d）,左室质量指数（LV Mass）及校正后的左室质量指数（LV Mass Corrected）等,还原型谷胱甘肽（glutathione,GSH）和氧化型谷胱甘肽（glutathione disulfide,GSSG）检测试剂盒检测心肌组织中GSH的含量,并计算大鼠的存活率。结果：与BC组相比,NS组左室后壁厚度明显变薄,室间隔厚度显著减小,GSH含量明显减少,存活率明显下降,左室质量指数及校正后的左室质量指数明显增大,差异均具有显著统计学意义（P〈0.05）;NAC组左室后壁厚度、室间隔厚度等未见明显减小,左室质量指数及校正后的左室质量指数未见明显增大GSH含量未见明显降低,差异均不具有统计学意义（P〈0.05）,但存活率明显下降,差异具有统计学意义（P〈0.05）;与NS组相比,NAC组左室后壁厚度增厚,室间隔厚度显著提高,左室质量指数及校正后的左室质量指数明显减小,GSH含量明显增高,差异均具有统计学意义（P〈0.05）,但存活率无明显统计学差异（P〉0.05）。结论：NAC能改善大鼠心肌梗死后心室结构的重塑,可能与抑制氧化应激,增加GSH的含量有关,但其对心肌梗死后大鼠的存活率无明显影响。     

Modified enrichment-serology procedure for detection of salmonellae in soy products.

A modified enrichment-serology (MES) procedure was used to reduce the time necessary for salmonella analysis. Naturally contaminated samples of soy products were preenriched in 1% proteose peptone for 6 h at 37 degrees C followed by inoculation into tetrathionate broth for 18 h at 37 degrees C. Two drops of the tetrathionate sample were inoculated into M broth. After incubation at 37 degrees C for 6 h, 0.85 ml of the mixture was formolized, and 0.1 ml of polyvalent H antiserum was added. After incubation in water bath at 50 degrees C for 1 h, the appearance of a typical floccular flagellar precipitate was observed in tubes positive for salmonellae. Over 3,000 samples were subjected to standard biochemical and serological procedures, and the results were compared with those of the MES method with a 96.7% correlation. Eleven of the samples (0.3%) were false-negative with the MES procedure, and 3% were false-negative with the U.S. Food and Drug Administration Bacteriological Analytical Manual procedure. The 3% negative samples by this latter procedure were subsequently found to be positive by the MES procedure. The MES procedure reduced the time required for salmonella analysis from 4 days to 32 h.