The role of the FliK molecular ruler in hook‐length control in Salmonella enterica

A molecular ruler, FliK, controls the length of the flagellar hook. FliK measures hook length and catalyses the secretion‐substrate specificity switch from rod‐hook substrate specificity to late substrate secretion, which includes the filament subunits. Here, we show normal hook‐length control and filament assembly in the complete absence of the C‐ring thus refuting the previous ‘cup’ model for hook‐length control. Mutants of C‐ring components, which are reported to produce short hooks, show a reduced rate of hook–basal body assembly thereby allowing for a premature secretion‐substrate specificity switch. Unlike fliK null mutants, hook‐length control in an autocleavage‐defective mutant of flhB, the protein responsible for the switch to late substrate secretion, is completely abolished. FliK deletion variants that retain the ability to measure hook length are secreted thus demonstrating that FliK directly measures rod‐hook length during the secretion process. Finally, we present a unifying model accounting for all published data on hook‐length control in which FliK acts as a molecular ruler that takes measurements of rod‐hook length while being intermittently secreted during the assembly process of the hook–basal body complex.     

Efficacy of dietary supplemental insoluble fibrous materials in ameliorating adverse effects of coccidial challenge in broiler chickens

ABSTRACT

The current experiment was designed to examine effects of dietary supplemental sunflower hulls (SH) and rice hulls (RH) on growth performance, carcass traits, intestinal morphology, lesion score and oocyst shedding in broiler chickens exposed to coccidial challenge. A total of 540 broiler chickens (Ross 308) were assigned to six dietary treatments based on a factorial arrangement (2 × 3) across 1–14, 14–28 and 28-42-d periods. Experimental treatments consisted of broiler chickens without or with coccidial challenge each offered with three different diets: a basal diet or basal diet supplemented with either RH or SH at 40 g/kg diet, respectively. Infection with Eimeria impaired daily weight gain (DWG) and feed conversion ratio (FCR) of broiler chickens during growing period (p < 0.05) while supplementation of SH or RH reduced the adverse effect of coccidiosis so that birds had similar DWG to those fed the basal diet without infection. However, only dietary SH improved the FCR of broilers challenged with coccidiosis. Regardless of coccidial challenge, dietary access to insoluble fibre improved performance of broilers across the growing period (p < 0.05); however, this effect was not observed during the entire rearing period. Relative weights of liver and pancreas were increased in birds subjected to coccidial challenge on d 21 of age (p < 0.05). Moreover, relative weights of the intestinal segments were enhanced (p < 0.05). Furthermore, gizzard weights were higher in birds receiving diets added with fibre (p < 0.05). Infection with coccidiosis decreased villus height and villus height to crypt depth ratio in duodenum of broilers which received the basal diet compared with those fed the same feed without coccidial challenge (p < 0.05). However, supplemental SH could decrease the negative effect of infection on the noted intestinal morphometric attributes. Similarly, a marked reduction was observed for lesion score and faecal oocyst excretion of challenged broilers fed on dietary supplemental fibre (p < 0.05). In conclusion, supplementation of insoluble fibre could ameliorate negative effects of coccidial challenge on DWG of broiler chickens and inclusion of SH in diet of birds exposed to Eimeria infection could be recommended.     

Light rhythmic exercise with dietary milk fat globule membrane improves physical fitness in an elderly Japanese population: a double-blind randomized placebo-controlled trial

Abstract

This study aimed to investigate the efficacy of home-based, light gymnastic exercise plus dietary milk fat globule membrane (MFGM) intake on physical fitness of an elderly Japanese sample in a pilot, double-blind, randomized, placebo-controlled trial. Seventy-one subjects (male, n = 13; female, n = 58) were randomly assigned into two groups: placebo (n = 35 [male, n = 6; female, n = 29]) and MFGM group (n = 36 [male, n = 7; female, n = 29]). The intervention was eight weeks. Subjects ingested either MFGM (1 g/day) or placebo tablets daily and engaged in an exercise program daily. Physical function tests were performed at baseline and after four and eight weeks. Foot tapping and open–close stepping scores significantly increased from baseline to eight weeks in the MFGM group. Study results suggest daily MFGM ingestion might further enhance the effects of light-intensity exercise in healthy elderly people.     

The mouth apparatus of the Cambrian gilled lobopodian Pambdelurion whittingtoni

Omnidens is a large feeding apparatus composed of circlets of teeth, first documented from the early Cambrian of China. Originally interpreted as the oral cone of a radiodontan, it was later reinterpreted as the introvert of a priapulan. In both cases the Omnidens mouthparts underpinned estimates of gigantic (c. 2 m) body size. Recent evidence has been used to suggest that pharyngeal teeth and radially‐arranged oral plates in the stem‐group onychophoran Hallucigenia and the lower stem‐group euarthropod Jianshanopodia are homologous to structures of the introvert in priapulans and other scalidophorans, and are thus primitive characters for moulting animals (Ecdysozoa) as a whole. Here we show that the early Cambrian gilled lobopodian Pambdelurion whittingtoni from Sirius Passet, Greenland, possesses a mouth apparatus identical to Omnidens, being composed of the same three zones with detailed similarities of sclerites in each zone. An oral cone with rings of pharyngeal teeth, radial plates and outer scalid‐like plates are ecdysozoan characters retained in the euarthropod stem group. Omnidens from China probably belongs to an unrecognized Pambdelurion‐like animal rather than being part of a giant priapulan.     

Influence of roughage/concentrate ratio and linseed oil on the concentration of trans-fatty acids and conjugated linoleic acid in duodenal chyme and milk fat of late lactating cows

Abstract

The objective of the study was to investigate the influence of two roughage-to-concentrate ratios, with or without linseed oil supplementation, on the flow of fatty acids in the intestinal chyme and the secretion in milk fat in late lactating cows. Seven late lactating cows fitted with cannulae in the dorsal rumen and simple T-shaped cannulae in the proximal duodenum were randomly assigned to four experimental periods applying an incomplete replicated 2×2 Latin square design. The rations consisted of meadow hay and a concentrate mixture given in a ratio of 70 : 30 or 30 : 70 on dry matter basis. The basal rations were fed without or with 200 g linseed oil daily. After three weeks of adaptation, samples from the duodenal chyme were taken to study the flow of fatty acids. Additionally, milk samples were analysed for their milk fat composition. Decreasing roughage/concentrate ratio and linseed oil supplementation significantly increased the flow of monounsaturated fatty acids (MUFA), trans-fatty acids (tFA) and conjugated linoleic acids (CLA) in the duodenum. Furthermore, linseed oil increased the flow of saturated fatty acids (SFA) in the duodenum. Higher concentrate portion (H 30) and linseed oil supplementation significantly decreased the milk fat content. SFA were lower (p < 0.05) and MUFA were higher (p < 0.05) in milk fat after linseed oil supplementation; H 30 resulted in more polyunsaturated fatty acids (PUFA, p < 0.05) in the milk. Linseed oil supplementation significantly increased tFA and CLA in milk fat. The higher CLA content in milk fat as compared to that in the digesta suggests that a substantial endogenous synthesis of CLA in the mammary gland tissue through Δ9-desaturase took place. Between 21% and 48% of duodenal t11-C_18:1 were converted into c9, t11-CLA in milk fat.     

The Nature and Organization of Filaments in the Oral Apparatus of Tetrahymena1

ABSTRACT. Filaments in the oral apparatus of Tetrahymena appear similar, but not identical, to the intermediate filaments of multicellular organisms. The mean diameter of filaments measured in the present study was 16.4 nm, but the range of variation was much greater than has been reported for intermediate filaments. The organization of filaments within the oral apparatus has been studied by indirect immunofluorescence microscopy and immunogold localization at the electron microscopical level using antiserum raised in rabbits against the major subunit protein of the oral filaments (87K). The filaments were found to be organized into cables, networks, and chambers or cages which encase the basal bodies. At the highest level of organization, the filaments connect into a rigid framework capable of maintaining the overall architecture in the absence of microtubules. Like intermediate filaments, the oral filaments are insoluble at high ionic strength, have evolutionarily non-conservative subunit proteins, are probably non-contractile, and serve to stabilize persistent cellular architecture.     

Association of Per3 length polymorphism with susceptibility of Alzheimer disease (AD) in Chinese population

Objectives: The association of Per3 length polymorphism with susceptibility of Alzheimer Disease (AD) was examined in the present study. Methods: This study was constructed using the case-control method and investigated the association of Per3 length polymorphism with susceptibility of AD. Genotypes of APOE and Per3 length were determined by a PCR restriction fragment length polymorphism detection method. Results: In this study, we gathered 130 unrelated AD patients and 188 controls in performing an analysis the association of Per3 length polymorphism with susceptibility of AD. In the whole sample or APOE ε4 non-carriers, an increased prevalence of five repeat homozygotes of Per3 length in AD patients had significant higher than that in controls (in the whole sample: χ² = 7.261,= 0.0176; in APOE ε4 non-carriers: χ² = 6.086, p = 0.030). And, among APOE ε4 carriers, an increased prevalence of five repeat homozygotes of Per3 length in AD patients had also significant higher than that in controls (χ² = 3.893, p = 0.0319). Conclusions: Among APOE ε4 non-carriers, five repeat homozygotes of Per3 length was associated with a high susceptibility of AD among APOE ε4 carriers and non-carriers.     

Plant growth promoting rhizhobacteria (PGPR)-mediated root proliferation in black pepper (Piper nigrum L.) as evidenced through GS Root software

Abstract

Pseudomonas fluorescens strains which are proven biocontrol agents in black pepper against foot rot (caused by Phytophthora capsici ) were also found to enhance root proliferation and fibre root production. Experiments conducted in the greenhouse with five efficient strains of P. fluorescens (IISR-6, IISR-8, IISR-11, IISR-13 and IISR-51) showed that the bacterial strains could significantly increase the root biomass of the plants (30 – 135%). Parameters for total root length, root area and root tips were estimated by scanning the entire root system and analysis through GS Root® software (PP systems, Winterstreet, USA). All the strains increased the root length in the treated plants (12 – 127%), the highest being with IISR-6, which was on a par with IISR-11 and IISR-51. A similar trend was observed with the total root area after bacterization (43 – 200%). The P. fluorescens treated plants had a higher number of feeder roots as evidenced by the increased number of root tips (82 – 137%). The enhanced growth parameters upon root bacterization could be corroborated with the production of the plant growth hormones IAA & GA by the bacterial strains and their P-solubilization potential.     

Mating and prey stage affecting life history,reproduction and life table of the predacious mite Phytoseiulus macropilis (Banks) (Acari: Phytoseiidae)

Abstract

Two factors were examined to determine their effect on the life history, reproduction and life table parameters in the predacious mite Phytoseiulus macropilis (Banks) in the laboratory. The factors studied included multiple mating and various prey stages of Tetranychus urticae Koch. When females fed on mixed actives (protonymphs and deutonymphs) of T. urticae, the fecundity of females mated more than once was 1.7 times higher than in females mated only once, also oviposition period and adult longevity was longer. The adult longevity and life span of P. macropilis were similar when fed on mixed actives, eggs (0 – 24-h-old) and (0 – 48-h-old) of T. urticae, while both periods were increased and reproduction was higher when fed on older eggs (72 – 96-h-old) of T. urticae. The total number of eggs deposited by females was significantly higher on eggs of (various ages) than on mixed actives of T. urticae. Life table parameters showed that a diet of (72 – 96-h-old) eggs of T. urticae provided the longest generation time (11.066 days) and female longevity (33.54 days) as well as the highest intrinsic rate of natural increase (rm = 0.36755) and greatest total fecundity which resulted in the highest net reproductive rate (Ro = 58.4136) value. The adult female consumed daily an average of 6.8 mixed actives of T. urticae during its life cycle, while it was increased to 13.6 during the oviposition period. The daily (72 – 96-h-old) eggs of T. urticae consumed by female P. macropilis during its life cycle and adult longevity was significantly higher than that recorded on either (0 – 24-h-old) or (0 – 48-h-old) eggs of T. urticae.     

Comparative ontogeny of the feeding apparatus of sympatric drums (Perciformes: Sciaenidae) in the Chesapeake Bay

The anatomy of the feeding apparatus in fishes, including both oral and pharyngeal jaw elements, is closely related to the ecology of a species. During ontogeny, the oral and pharyngeal jaws undergo dramatic changes. To better understand how such ontogenetic changes occur and relate to the feeding ecology of a species, ontogenetic series of four closely related members of the family Sciaenidae (Cynoscion nebulosus, Cynoscion regalis, Micropogonias undulatus, and Leiostomus xanthurus) were examined. Sciaenids were selected because as adults they exhibit considerable specialization of the feeding apparatus correlated with differences in foraging habitats. However, it is not clear when during ontogeny the structural specializations of the feeding apparatus develop, and thereby enable early life history stage (ELHS) sciaenids to partition their foraging habitats. A regression tree was recovered from the analysis and three divergences were identified during ontogeny. There are no measurable differences in elements of the feeding apparatus until the first divergence at 8.4 mm head length (HL), which was attributed to differences in average gill filament length on the second ceratobranchial. The second divergence occurred at 14.1 mm HL and was associated with premaxilla length. The final divergence occurred at 19.8 mm HL and was associated with differences in the toothed area of the fifth certatobranchial. These morphological divergences suggest that ELHS sciaenids may be structurally able to partition their foraging habitats as early as 8.4 mm HL. J. Morphol. 277:183–195, 2016. © 2015 Wiley Periodicals, Inc.     

Effect of Adopters' Lifestyles and Animal-Care Knowledge on Their Expectations Prior to Companion-Animal Guardianship

Human expectations can greatly affect the human–companion animal relationship, sometimes putting nonhuman animals at risk for relinquishment. At 20 animal shelters in Southern Ontario, Canada, potential adopters (N = 234) completed a questionnaire regarding their lifestyle, companion animal-care knowledge, and preadoption expectations of their adopted companion animals. Linear mixed models were used to assess the associations of adopters' lifestyles and companion animal-care knowledge with their expectations for animal behavior, the human–companion animal relationship, and the effort required in companion-animal guardianship. Dog adopters had higher expectations than cat adopters for their companion animal's behavior (p < .001), the human–companion animal relationship (p < .001), and the effort required in companion-animal guardianship (p < .001). Adopters' human relationship statuses were also associated with expectations for the human–companion animal relationship (p = .002). As adopters' companion animal-care knowledge increased, so did their expectations for the effort required in companion-animal guardianship (p < .001). An understanding of adopters' expectations prior to adoption will help animal shelters better match, educate, and prepare adopters for their lives with companion animals.     

Association between red blood cell distribution width and long-term mortality among patients undergoing percutaneous coronary intervention with previous history of cancer

Abstract

Background: The number of patients suffering from coronary heart disease with cancer is rising. There is scarce evidence concerning the biomarkers related to prognosis among patients undergoing percutaneous coronary intervention (PCI) with cancer. Thus, the aim of this study was to investigate the association between red blood cell distribution width (RDW) and prognosis in this population.

Methods: A total of 172 patients undergoing PCI with previous history of cancer were enrolled in this retrospective study. The endpoint was long-term all-cause mortality. According to tertiles of RDW, the patients were classified into three groups: Tertile 1 (RDW <12.8%), Tertile 2 (RDW ≥12.8% and <13.5%) and Tertile 3 (RDW ≥13.5%).

Results: During an average follow-up period of 33.3 months, 29 deaths occurred. Compared with Tertile 3, mortality of Tertile 1 and Tertile 2 was significantly lower in the Kaplan–Meier analysis. In multivariate Cox regression analysis, RDW remained an independent risk factor of mortality (HR: 1.938, 95% CI: 1.295–2.655, p?<?0.001). The all-cause mortality in Tertile 3 was significantly higher than that in Tertile 1 (HR: 5.766; 95% CI: 1.426–23.310, p?=?0.014).

Conclusions: An elevated RDW level (≥13.5%) was associated with long-term all-cause mortality among patients undergoing PCI with previous history of cancer.     

IMMUNOLOCALIZATION OF CENTRIN IN OXYRRHIS MARINA (DINOPHYCEAE)1

A new polyclonal antibody was raised against centrin isolated from the flagellate green alga Spermatozopsis similis (Chlorophyta; anti-SSC). It stains by immunofluorescence and immunoelectron microscopy well-known reference systems for centrin like the nucleus–basal body connectors in Chlamydomonas reinhardtii (Chlorophyta) and the system II fibers (rhizoplasts) of Scherffelia dubia (Chlorophyta). In addition, it recognizes in immunoblots a single 20-kDa protein in isolated cytoskeletons of Spermatozopsis similis and Tetraselmis striata (Chlorophyta) as well as purified centrin isolated from Tetraselmis striata. Using this antibody, centrin was localized in whole cells and isolated cytoskeletons of Oxyrrhis marina Dujardin (Dinophyceae) by immunofluorescence and immunogold electron microscopy. In the flagellar apparatus of O. marina, five different structures were antigenic. Four short fibers (connectives 1–4) link the basal bodies to the four major fibrous flagellar roots, which do not cross-react with anti-centrin. The most prominent of the labeled structures (connective 5), a crescent-shaped fiber, extends from the flagellar canal of the transverse flagellum along the base of the tentacle to the flagellar canal of the longitudinal flagellum, interconnecting the distal parts of the microtubular roots/bands in the basal apparatus. For most of its length, it underlies and is connected to a transversely oriented subamphiesmal microtubular band. In immunoblot analyses, anti-SSC recognizes only a single 20-kDa protein in cytoskeletons of O. marina. Functional and phylogenetic aspects of centrin-containing structures in dinoflagellates are discussed.     

First Jurassic dinosaur tracksite from Guizhou Province,China: morphology,trackmaker and paleoecology

Abstract

Sauropod tracks from the Early Jurassic Maanshan Member of the Ziliujing Formation in the Dazhuanwan area of Guizhou represent the first Jurassic dinosaur track record for this province. The best preserved and longest trackway is narrow gauge (Brontopodus type), and indicates a relatively small trackmaker (footprint length ~35.0 cm). In conjunction with sauropodomorph skeletal remains these tracks suggest that basal sauropodomorphs and primitive sauropods coexisted in this region during the Early Jurassic. This pattern is same in the Lufeng and Sichuan basins. Thus, sauropod tracks from southwest China are diverse in the Early Jurassic, and include narrow gauge Parabrontopodus, wide gauge Brontopodus-type, and basal sauropodomorph tracks.     

Day-night variations in pro-oxidant reactions of hypothalamic,hepatic and pancreatic tissue in mice with spontaneous obesity (Neotomodon alstoni)

Objectives: The present work compares the pro-oxidant properties in hypothalamic, hepatic, and pancreatic tissue of spontaneously obese and lean Neotomodon alstoni during day and night. Methods: Lipid peroxidation from hypothalamus, liver, and pancreas from lean and obese mice were quantified by the two-thiobarbituric acid method. Lipid peroxidation in vivo was also determined by means of detection of conjugated dienes in lipid extracts. Results: Hypothalamic tissue from obese Neotomodon showed a notorious increase (nearly 700%) in the production of thiobarbituric acid-reactive substances (TBARS) at day, either in basal as well as in an assay supplemented with Fe²⁺; the presence of conjugated dienes was also notably greater (76%) at day. Hypothalamus of lean mice presented an increase (170%) in assay supplemented with Fe²⁺. Hepatic tissue in obese mice showed diurnal increasing in TBARS + Fe²⁺ (34%) and in conjugated dienes (38%), while lean mice showed only a diurnal increase (45%) in TBARS + Fe²⁺. Pancreatic tissue from obese mice presented a diurnal increasing in basal TBARS (130%) but a decrease (72%) in TBARS + Fe²⁺. Presence of conjugated dienes was also decreased during the day in lean (60%) and in obese (40%) mice. Conclusions: In the obese Neotomodon, there is a larger day–night change in pro-oxidant status in the hypothalamus and in pancreas than the one observed in the liver, suggesting a differential equilibrium between oxidative reactions and antioxidant defenses in the different tissues during the day–night cycle.     

The conodont animal

A unique specimen of a small, elongate, soft-bodied animal from the Lower Carboniferous of the Edinburgh district, Scotland, is described. The head expands anteriorly into two lobate structures flanking a central lumen; behind this lies a conodont apparatus, apparently in situ, consisting of an aligned set of ramiform elements followed by a pair of ozarkodiniform elements and one of platform elements. From the morphology of the platform elements the animal has been identified as Clydagnathus? cf. cavusformis. Repeated structures which may represent segments are evident in the posterior part of the trunk, which bears a posterior and a caudal fin, each supported by rays. The animal shows similarities to both chordates and chactognaths, but the evidence supports its assignment to a separate phylum, the Conodonta. The function of the conodonts remains equivocal, but it seems more likely that they served as teeth than as internal supports.     

Paleobiology of the Late Cretaceous sclerorhynchid sawfish,Ischyrhiza mira (Elasmobranchii: Rajiformes), from North America based on new anatomical data

Abstract

We describe seven associated skeletal remains of Ischyrhiza mira, a Late Cretaceous sclerorhynchid sawfish, from the Campanian?lower Maastrichtian of Tennessee and Alabama, U.S.A., to decipher its paleobiology. Ischyrhiza mira had about 16 or 17 functional spines and about the same number of replacement spines on each side of the rostrum in which tall erect spines occupied the anterior one-half to two-third of the rostrum followed posteriorly by smaller spines. Whereas small hat-shaped dermal denticles were distributed on the rostrum, large thorn-like dermal denticles were present on the dorsal side of the body characteristic of sluggish, benthic batoids. We concur with the interpretation that specimens previously identified as rostral spines of Peyeria are actually enlarged thorn-like dermal denticles of a sclerorhynchid. We suggest that the ratio between the rostrum length and total body length of sclerorhynchids was generally about 1:3.27. Our vertebra-based ontogenetic analysis of I. mira gives an age estimate of 12.4 years for a 190-cm-long individual, the size at birth of about 0.5 m, and the maximum possible length for the species of no more than 3 m. Compared to extant pristid sawfishes, I. mira probably became sexually mature much earlier with a slightly faster rate of rostrum development.     

Effects of Enterococcus faecalis on egg production,egg quality and caecal microbiota of hens during the late laying period

This study was conducted to determine the effects of diet supplementation of laying hens with Enterococcus faecalis (EF) on egg production, egg quality and caecal microbiota. A total of 360 Hy-Line Brown laying hens (72 weeks old) were divided into three groups with four replicates of 30 birds each. The laying hens were fed with the basal diet (Control), the basal diet + 3.75 · 10⁸ cfu EF/kg (Group I) or the basal diet + 7.5 · 10⁸ cfu EF/kg (Group II). The experiment lasted for 45 d. Eggs and caecal samples were collected at the end of the experiment. Results showed that dietary supplementation with EF did not affect the average daily egg weight, cracked egg rate, mortality and egg quality. However, EF supplementation caused a significantly increased laying rate and decreased feed/egg ratio (p < 0.05). The differences in caecal microbiota between Group II and the Control were significant. The relative abundance of Verrucomicrobia and Cyanobacteria at the phylum level, Rikenellaceae, Christensenellaceae and Veillonellaceae at the family level, and the Faecalibacterium, Christensenellaceae R-7 group and Eubacterium coprostanoligenes group at the genus level changed significantly in Group II compared with the Control (p < 0.05). In conclusion, the tested dietary supplementations with EF improved product performance and affected the caecal microbial community structure of laying hens during the late laying period.     

Daily rhythms after vaccination on specific and non-specific responses in Nile tilapia (Oreochromis niloticus)

ABSTRACT

We evaluated the daily changes in immunological and hematological factors in tilapia (Oreochromis niloticus) after an immunization period with a subsequent challenge. Experiments were divided into two phases: Phase 1 (immunization): 144 fish were distributed into two groups with 72 fish in six tanks. One group (T1) was immunized, comprising six vaccination time points (ZT schedule = ZT2 h, ZT6 h, ZT10 h, ZT14 h, ZT18 h, ZT22 h). The same schedule was applied to the other group, but with saline solution (non-vaccinated: T2). Both groups remained in the laboratory for 30 days (considered the immunization period). Phase 2 (challenge): on day 30, both vaccinated and non-vaccinated groups were challenged with Streptococcus agalactiae (2.0 × 10⁷ CFU mL^?1) following the same ZT schedule to stimulate the immune response without leading to widespread infection and mortality. On day 45, blood and head kidney samples were collected during the same ZT schedule. The variations in time of the following parameters within each group were evaluated: hematology, peroxidase activity, IgM, tnf-α3, tgf-β1, il-1β and il-12 gene expression. No significant mortality was observed for the groups or the ZT schedule (p > 0.05). Daily rhythms with diurnal acrophases were found in T2 for il12, tnf-α3 and tgf-β1 expression gene, while the acrophases of the peroxidase level, hematocrit and thrombocytes were at nighttime (p < 0.05). In contrast, most of the parameters in the vaccinated tilapia showed no daily rhythms (p > 0.05), except IgM. For all the parameters, the interaction effect between time and treatment (vaccinated and non-vaccinated groups) depended on ZT. Our results reveal that the humoral and non-specific immune system displayed a circadian rhythm based on the light-dark cycle, which could be affected by the vaccination procedure in tilapia.     

Developmental Aspects of Ultrastructure and Histochemistry of the Stylar Transmitting Tissue of Nicotiana sylvestris

The structure and histochemistry of the solid style of Nicotiana sylvestris Speg. and Comes have been studied by light and electron microscopy. The transmitting tissue develops large intercellular spaces filled with secretions rich in proteins and carbohydrates during maturation. The cells possess large nuclei, numerous plastids with starch grains, mitochondria, ribosomes and well developed endoplasmic reticulum and golgi apparatus. The plastids in the stylar region immediately below the stigma produce electron-dense osmiophilic substances which are probably transferred into the cytoplasm by a process resembling budding-off of vesicles. The Golgi apparatus may use the starch grains as a source of sugars for the synthesis and secretion of extracellular polysaccharides. The structural and cytochemical differences between the glandular cells of the stigma and the stylar transmitting tissue are discussed.