Effect of antiserum to luteinizing hormone (LHAS) on the physiology of the epididymis and accessory glands in the albino rat

Rabbit antiserum specific to ovine luteinizing hormone free of contaminating antibodies to nonspecific proteins and FSH was administered to adult, intact rats at a dose of 0.1 and 0.2 ml/day for five days. LHAS had no effect on the weights of the epididymis but decreased their secretory activity to castrate level. Administration of 0.2 ml of LHAS or castration resulted in a marked and comparable reduction in the weights and secretory activity of the accessory glands. LHAS, even at a lower dose (0.1 ml/day), caused a significant reduction in the content of sialic acid in the vas deferons and Cowper's glands. These results are discussed in relation to the factors that regulate the functions of the epididymis and accessory glands.

Hierarchical modelling of acclimatory processesstar, open

The term acclimation has been used with several connotations in the field of acclimatory physiology. An attempt has been made, in this paper, to define precisely the term “acclimation” for effective modelling of acclimatory processes. Acclimation is defined with respect to a specific variable, as cumulative experience gained by the organism when subjected to a step change in the environment. Experimental observations on a large number of variables in animals exposed to sustained stress, show that after initial deviation from the basal value (defined as “growth”), the variables tend to return to basal levels (defined as “decay”). This forms the basis for modelling biological responses in terms of their growth and decay. Hierarchical systems theory as presented by Mesarovic, Macko & Takahara (1970) facilitates modelling of complex and partially characterized systems. This theory, in conjunction with “growth-decay” analysis of biological variables, is used to model temperature regulating system in animals exposed to cold. This approach appears to be applicable at all levels of biological organization. Regulation of hormonal activity which forms a part of the temperature regulating system, and the relationship of the latter with the “energy” system of the animal of which it forms a part, are also effectively modelled by this approach. It is believed that this systematic approach would eliminate much of the current circular thinking in the area of acclimatory physiology.

Selective attention in a synchronising bushcricket: physiology

Synchronising bushcricket males achieve synchrony by delaying their chirps in response to calling neighbours. In multi-male choruses, males that delay chirps in response to all their neighbours would remain silent most of the time and be unable to attract mates. This problem could be overcome if the afferent auditory system exhibited selective attention, and thus a male interacted only with a subset of neighbours. We investigated whether individuals of the bushcricket genus Mecopoda restricted their attention to louder chirps neurophysiologically, behaviourally and through spacing. We found that louder leading chirps were preferentially represented in the omega neuron but the representation of softer following chirps was not completely abolished. Following chirps that were 20 dB louder than leading chirps were better represented than leading chirps. During acoustic interactions, males synchronised with leading chirps even when the following chirps were 20 dB louder. Males did not restrict their attention to louder chirps during interactions but were affected by all chirps above a particular threshold. In the field, we found that males on average had only one or two neighbours whose calls were above this threshold. Selective attention is thus achieved in this bushcricket through spacing rather than neurophysiological filtering of softer signals.

Selective attention in a synchronising bushcricket: physiology, behaviour and ecology

Synchronising bushcricket males achieve synchrony by delaying their chirps in response to calling neighbours. In multi-male choruses, males that delay chirps in response to all their neighbours would remain silent most of the time and be unable to attract mates. This problem could be overcome if the afferent auditory system exhibited selective attention, and thus a male interacted only with a subset of neighbours. We investigated whether individuals of the bushcricket genus Mecopoda restricted their attention to louder chirps neurophysiologically, behaviourally and through spacing. We found that louder leading chirps were preferentially represented in the omega neuron but the representation of softer following chirps was not completely abolished. Following chirps that were 20 dB louder than leading chirps were better represented than leading chirps. During acoustic interactions, males synchronised with leading chirps even when the following chirps were 20 dB louder. Males did not restrict their attention to louder chirps during interactions but were affected by all chirps above a particular threshold. In the field, we found that males on average had only one or two neighbours whose calls were above this threshold. Selective attention is thus achieved in this bushcricket through spacing rather than neurophysiological filtering of softer signals.

Selective attention in a synchronising bushcricket: physiology, behaviour and ecology

Synchronising bushcricket males achieve synchrony by delaying their chirps in response to calling neighbours. In multi-male choruses, males that delay chirps in response to all their neighbours would remain silent most of the time and be unable to attract mates. This problem could be overcome if the afferent auditory system exhibited selective attention, and thus a male interacted only with a subset of neighbours. We investigated whether individuals of the bushcricket genus Mecopoda restricted their attention to louder chirps neurophysiologically, behaviourally and through spacing. We found that louder leading chirps were preferentially represented in the omega neuron but the representation of softer following chirps was not completely abolished. Following chirps that were 20 dB louder than leading chirps were better represented than leading chirps. During acoustic interactions, males synchronised with leading chirps even when the following chirps were 20 dB louder. Males did not restrict their attention to louder chirps during interactions but were affected by all chirps above a particular threshold. In the field, we found that males on average had only one or two neighbours whose calls were above this threshold. Selective attention is thus achieved in this bushcricket through spacing rather than neurophysiological filtering of softer signals.

Choosing an appropriate index to construct dominance hierarchies in animal societies: a comparison of three indices

A plethora of indices have been proposed and used to construct dominance hierarchies in a variety of vertebrate and invertebrate societies, although the rationale for choosing a particular index for a particular species is seldom explained. In this study, we analysed and compared three such indices, viz Clutton-Brock et al.'s index (CBI), originally developed for red deer, Cervus elaphus, David's score (DS) originally proposed by the statistician H. A. David and the frequency-based index of dominance (FDI) developed and routinely used by our group for the primitively eusocial wasps Ropalidia marginata and Ropalidia cyathiformis. Dominance ranks attributed by all three indices were strongly and positively correlated for both natural data sets from the wasp colonies and for artificial data sets generated for the purpose. However, the indices differed in their ability to yield unique (untied) ranks in the natural data sets. This appears to be caused by the presence of noninteracting individuals and reversals in the direction of dominance in some of the pairs in the natural data sets. This was confirmed by creating additional artificial data sets with noninteracting individuals and with reversals. Based on the criterion of yielding the largest proportion of unique ranks, we found that FDI is best suited for societies such as the wasps belonging to Ropalidia, DS is best suited for societies with reversals and CBI remains a suitable index for societies such as red deer in which multiple interactions are uncommon. (C) 2009 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.

Retention Time Variability as a Mechanism for Animal Mediated Long-Distance Dispersal

Long-distance dispersal (LDD) events, although rare for most plant species, can strongly influence population and community dynamics. Animals function as a key biotic vector of seeds and thus, a mechanistic and quantitative understanding of how individual animal behaviors scale to dispersal patterns at different spatial scales is a question of critical importance from both basic and applied perspectives. Using a diffusion-theory based analytical approach for a wide range of animal movement and seed transportation patterns, we show that the scale (a measure of local dispersal) of the seed dispersal kernel increases with the organisms' rate of movement and mean seed retention time. We reveal that variations in seed retention time is a key determinant of various measures of LDD such as kurtosis (or shape) of the kernel, thinkness of tails and the absolute number of seeds falling beyond a threshold distance. Using empirical data sets of frugivores, we illustrate the importance of variability in retention times for predicting the key disperser species that influence LDD. Our study makes testable predictions linking animal movement behaviors and gut retention times to dispersal patterns and, more generally, highlights the potential importance of animal behavioral variability for the LDD of seeds.

Better early osteogenesis of electroconductive hydroxyapatite-calcium titanate composites in a rabbit animal model

In view of the fact that bone healing can be enhanced due to external electric field application, it is important to assess the influence of the implant conductivity on the bone regeneration in vivo. To address this issue, this study reports the in vivo biocompatibility property of multistage spark plasma sintered hydroxyapatite (HA)-80 wt % calcium titanate (CaTiO3) composites and monolithic HA, which have widely different conductivity property (14 orders of magnitude difference). The ability of bone regeneration was assessed by implantation in cylindrical femoral bone defects of rabbit animal model for varying time period of 1, 4, and 12 weeks. The overall assessment of the histology results suggests that the progressive healing of bone defects around HA-80 wt % CaTiO3 is associated with a better efficacy with respect to (w.r.t) early stage neobone formation, which is histomorphometrically around 140% higher than monolithic HA. Overall, this study demonstrates that the in vivo biocompatibility property of HA-80 wt % CaTiO3 with respect to local effects after 12 weeks of implantation is not compromised both qualitatively and quantitatively, and a comparison with control implant (HA) points toward the critical role of electrical conductivity on better early stage bone regeneration. (c) 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 842-851, 2014.

In vitro osteogenic cell proliferation, mineralization, and in vivo osseointegration of injection molded high-density polyethylene-based hybrid composites in rabbit animal model

The present work reports the biocompatibility property of injection molded HDPE-HA-Al2O3 hybrid composites. In vitro cytocompatibility results reveal that osteogenic cell viability and bone mineralization are favorably supported in a statistically significant manner on HDPE-20% HA-20% Al2O3 composite, in comparison to HDPE-40 wt.% HA or HDPE-40 wt.% Al2O3. The difference in cytocompatibility property is explained in terms of difference in substrate wettability/surface energy and importantly, both the cell proliferation at 7 days or bone mineralization at 21 days on HDPE-20% HA-20% Al2O3 composite are either comparable or better than sintered HA. The progressive healing of cylindrical femoral bone defects in rabbit animal model was assessed by implantation experiments over 1, 4 and 12 weeks. Based on the histological analysis as well as histomorphometrical evaluation, a better efficacy of HDPE-20% HA-20% Al2O3 over high-density polyethylene (HDPE) for bone regeneration and neobone formation at host bone-implant interface was established. Taken together, the present study unequivocally establishes that despite the presence of 20% Al2O3, HDPE-based hybrid composites are as biocompatible as HA in vitro or better than HDPE in vivo.

Turing and animal coat patterns

The present article describes a beautiful contribution of Alan Turing to our understanding of how animal coat patterns form. The question that Turing posed was the following. A collection of identical cells (or processors for that matter), all running the exact same program, and all communicating with each other in the exact same way, should always be in the same state. Yet they produce nonhomogeneous periodic patterns, like those seen on animal coats. How does this happen? Turing gave an elegant explanation for this phenomenon, namely that differences between the cells due to small amounts of random noise can actually be amplified into structured periodic patterns. We attempt to describe his core conceptual contribution below.

Development, in vitro and in vivo characterization of zoledronic acid functionalized hydroxyapatite nanoparticle based formulation for treatment of osteoporosis in animal model

We investigated the potential of using novel zoledronic acid (ZOL)-hydroxyapatite (HA) nanoparticle based drug formulation in a rat model of postmenopausal osteoporosis. By a classical adsorption method, nanoparticles of HA loaded with ZOL (HNLZ) drug formulation with a size range of 100-130 nm were prepared. 56 female Wistar rats were ovariectomized (OVX) or sham-operated at 3 months of age. Twelve weeks post surgery, rats were randomized into seven groups and treated with various doses of HNLZ (100, 50 and 25 mu g/kg, intravenous single dose), ZOL (100 mu g/kg, intravenous single dose) and HA nanoparticle (100 mu g/kg, intravenous single dose). Untreated OVX and sham OVX served as controls. After three months treatment period, we evaluated the mechanical properties of the lumbar vertebra and femoral mid-shaft. Femurs were also tested for trabecular microarchitecture. Sensitive biochemical markers of bone formation and bone resorption in serum were also determined. With respect to improvement in the mechanical strength of the lumbar spine and the femoral mid-shaft, the therapy with HNLZ drug formulation was more effective than ZOL therapy in OVX rats. Moreover, HNLZ drug therapy preserved the trabecular microarchitecture better than ZOL therapy in OVX rats. Furthermore, the HNLZ drug formulation corrected increase in serum levels of bone-specific alkaline phosphatase, procollagen type I N-terminal propeptide, osteocalcin, tartrate-resistant acid phosphatase 5b and C-telopeptide of type 1 collagen better than ZOL therapy in OVX rats. The results strongly suggest that HNLZ novel drug formulation appears to be more effective approach for treating severe osteoporosis in humans. (C) 2014 Elsevier B.V. All rights reserved.

A Kunitz-type serine protease inhibitor from Butea monosperma seed and its influence on developmental physiology of Helicoverpa armigera

A protease inhibitor from the seeds of Butea monosperma (BmPI) was purified, characterized and studied for its influence on developmental physiology of Helicover-pa armigera. BmPI on two-dimensional separations indicated the presence of a 14 kDa protein with an isoelectric point in the acidic region (pl 5.6). Multiple Sequence Analysis data suggested that the BmPI contains a sequence motif which is conserved in various trypsin and chymotrypsin inhibitors of Kunitz-type. The inhibitor exhibited trypsin inhibitory activity in a broad range of pH (4-10) and temperature (10-80 degrees C). The enzyme kinetic studies revealed BmPI as a competitive inhibitor with a K-i value of 1.2 x 10(-9) M. In vitro studies with BmPI indicated measurable inhibitory activity on total gut proteolytic enzymes of H. armigera (IC(50)2.0 mu g/ml) and bovine trypsin. BmPI supplemented artificial diet caused dose dependent mortality and reduction in growth and weight. The fertility and fecundity of H. armigera, declined whereas the larval-pupal duration of the insect life cycle extended. These detrimental effects on H. armigera suggest the usefulness of BmPl in insect pest management of food crops. (C) 2014 Elsevier Ltd. All rights reserved.

Novel Functions of (p)ppGpp and Cyclic di-GMP in Mycobacterial Physiology Revealed by Phenotype Microarray Analysis of Wild-Type and Isogenic Strains of Mycobacterium smegmatis

The bacterial second messengers (p)ppGpp and bis-(3'-5')-cyclic dimeric GMP (c-di-GMP) regulate important functions, such as transcription, virulence, biofilm formation, and quorum sensing. In mycobacteria, they regulate long-term survival during starvation, pathogenicity, and dormancy. Recently, a Pseudomonas aeruginosa strain lacking (p) ppGpp was shown to be sensitive to multiple classes of antibiotics and defective in biofilm formation. We were interested to find out whether Mycobacterium smegmatis strains lacking the gene for either (p)ppGpp synthesis (Delta rel(Msm)) or c-di-GMP synthesis (Delta dcpA) would display similar phenotypes. We used phenotype microarray technology to compare the growth of the wild-type and the knockout strains in the presence of several antibiotics. Surprisingly, the Delta rel(Msm) and Delta dcpA strains showed enhanced survival in the presence of many antibiotics, but they were defective in biofilm formation. These strains also displayed altered surface properties, like impaired sliding motility, rough colony morphology, and increased aggregation in liquid cultures. Biofilm formation and surface properties are associated with the presence of glycopeptidolipids (GPLs) in the cell walls of M. smegmatis. Thin-layer chromatography analysis of various cell wall fractions revealed that the levels of GPLs and polar lipids were reduced in the knockout strains. As a result, the cell walls of the knockout strains were significantly more hydrophobic than those of the wild type and the complemented strains. We hypothesize that reduced levels of GPLs and polar lipids may contribute to the antibiotic resistance shown by the knockout strains. Altogether, our data suggest that (p)ppGpp and c-di-GMP may be involved in the metabolism of glycopeptidolipids and polar lipids in M. smegmatis.